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The E

ffect of Airborne-particle A

brasion on the Surface C

haracteristics of M

onolithic Zirconia and the S

hear Bond S

trength

치 학 사학 문

The Effect of Airborne-particle Abrasion on the

Surface Characteristics of Monolithic Zirconia

and the Shear Bond Strength

다양한 샌드블라스 조건

지 코니아 물 레진 시 트

결합강도에 미치는 과에 한 연

2013 2월

울 학 학원

치 과학과 치과보철학전공

문 지

2

0

1

3

문

지

치 학 사학 문


Surface Characteristics of Monolithic Zirconia

and the Shear Bond Strength

다양한 샌드블라스 조건

지 코니아 물 레진 시 트

결합강도에 미치는 과에 한 연

2013 2월

울 학 학원

치 과학과 치과보철학 공

문 지

학 문 원문제공 비스에 한 동

본 학 문에 하여 울 학 가 아래 같 학 문 저 물

제공하는 것에 동 합니다.

1. 동 사항

① 본 문 보존 나 등 통한 라 비스 적 로 복

제할 경우 저 물 내 변경하지 않는 내에 복제 허 합

니다.

② 본 문 지 하여 등 정보통신망 통한 문

또는 전 복 제 포 전 시 무료로 제공하는 것에 동 합니다.

2. 개 (저 ) 무

본 문 저 타 에게 양도하거나 또는 허락하는 등 동 내

변경하고 할 는 학(원)에 공개 보 또는 해지 즉시 통

보하겠습니다.

3. 울 학 무

① 울 학 는 본 문 에 제공할 경우 저 보 치(DRM)

사 하여야 합니다.

② 울 학 는 본 문에 한 공개 보나 해지 신청 시 즉시 처리

해야 합니다.

문제 : The effect of airborne-particle abrasion on the surface characteristics of monolithic zirconia and the shear bond strength

학 : □ 사 ■ 사

학 과 : 치 과학과 (치과보철학전공)

학 : 2010-31187

연 락 처 :

저 : 문 지 ( )

제 : 2012 11 월 23

울 학 귀하


Surface Characteristics of Monolithic Zirconia and

the Shear Bond Strength

2013

Ji-Eun Moon, DDS, MSD

Department of Prosthodontics, Graduate School, Seoul National University

(Directed by Prof., Sung-Hun Kim, DDS, PhD)

2

CONTENTS

ABSTRACT --------------------------------------------------------------- 3

1. INTRODUCTION ------------------------------------------------------- 5

2. MATERIAL and METHODS

2. 1. Evaluation of microstructural changes of airborne-particle

abraded monolithic zirconia ceramic ------------------------------- 9

2. 2. Shear bond strength of resin cement ------------------------------- 16

3. RESULTS

3. 1. Microstructural changes -------------------------------------------- 19

3. 2. Shear bond strength ------------------------------------------------- 39

4. DISCUSSION ------------------------------------------------------------- 48

5. CONCLUSIONS --------------------------------------------------------- 56

REFERENCES ----------------------------------------------------------- 57

APPENDIX

KOREAN ABSTRACT

3

ABSTRACT

Purpose. This study was designed to evaluate the effects of several airborne-

particle abrasion protocols on the surface characteristics of monolithic

zirconia and to examine the effect of protocol choice on the shear bond

strength of resin cement.

Material and Methods. Two forms of monolithic zirconia specimens, 375

bar-shaped (45 × 4 × 3 mm) and 500 disc-shaped (Ø 9 × 1 mm), were

divided into 25 groups. All specimens were abraded with one of three

different sizes of alumina particles (25, 50 or 125 μm), two different

pressures (2 or 4 bar), two distinct application times (10 or 20s) and two

distinct incidence angles (45 or 90°). The bar-shaped specimens were used

for a 3-point bending test and determination of flexural strengths; Weibull

parameters were calculated for these specimens. The transformed

monoclinic phase (XM) was examined with X-ray diffractometry and Raman

spectrometry. Surface characteristics were investigated with SEM, confocal

laser scanning microscopy and AFM. The disc-shaped specimens were used

to determine the shear bond strength of resin cement (Panavia F2.0) before

and after thermocycling (5000 cycles). The fractured surfaces were

examined with SEM. All data were analyzed using 4-way ANOVA and a

multiple comparisons Scheffé test (α = .05).

4

Results. Specimens abraded with the 25 μm particles showed significantly

increased flexural strength compared to the control group; however,

differences between specimens abraded with 50 and 125 μm were

insignificant. The particle size and abrasion pressure and time significantly

affected the flexural strength, while the incidence angle was insignificant.

The XM and surface roughness were proportional to the size, pressure, time

and incidence angle. The Raman spectrum analysis showed a higher

proportion of the monoclinic phase as the depth of the specimen was closer

to the abraded surface. Under SEM and AFM observation, the larger particle

groups showed a more substantial roughening effect. In bonding with resin

cement, the highest shear bond strength after thermocycling was obtained by

the abrasion with 50 μm particles at 4 bar for 20s, regardless of incidence

angle.

Conclusion. Airborne-particle abrasion causes modification of the specimen

flaw distribution, transformation of the crystal structure, and an increase in

the shear bond strength of resin cement. Based on this study, the

recommended protocol for airborne-particle abrasion is a 50 μm particle

surface at 4 bar for 20s using an angle of either 45° or 90°.

Keyword: Monolithic Y-TZP; Airborne-particle abrasion; Phase transformation; Flexural strength; Shear bond strength Student number: 2010 – 31187

5

1. INTRODUCTION

In response of the high demand for highly esthetic, metal-free and

biocompatible restoration materials with high flexural strength, various

types of all-ceramic systems have been developed in the last few decades. In

a systematic review, all-ceramic crowns showed comparable survival rates

to metal-ceramic crowns when used in the anterior and or premolar regions,

but had a significantly higher fracture rate when used in the posterior region

[1]. Substantial effort has been put forth in the development of more reliable

all-ceramic systems. In the early 1990s, yttria-stabilized tetragonal zirconia

polycrystal (Y-TZP) was introduced to dentistry as a core material for all-

ceramic restorations. It is fabricated through the computer-aided

design/computer-aided manufacturing (CAD/CAM) technique. Compared to

other all-ceramic systems, results with Y-TZP have been encouraging, as it

has shown high resistance to fracture [2, 3].

Although damage to a zirconia framework has been reported only rarely,

chipping or fracturing of the ceramic veneer has been proposed as the most

frequent reason for failure of zirconia-based restorations [4-6]. Chip-off

fractures occur at a rate between 0% and 69% after 36 to 60 months of

follow-up [4-6]. Therefore, in order to increase the success rate of

restoration and overcome the chipping problem, zirconia restoration without

6

veneering ceramic, called a monolithic zirconia restoration system, was

introduced. Currently, monolithic zirconia restorations are constructed by

CAD/CAM and then only polished or characterized using a glaze layer.

Many studies of monolithic zirconia restorations have shown improved

clinical and laboratory results [7-9]. Their strong bond strength is

indispensable for the long-term durability of restorations. Manufacturers

also claim that zirconia ceramic restorations can be successfully cemented

with either conventional or adhesive cements. Nevertheless, some zirconia

fixed partial dentures (FPDs) show reduced retention with abutments. A

strong, durable resin bond to dental ceramics is established by the formation

of chemical bonds and micromechanical interlocking, and achieving reliable

and stable bond to zirconia remains a challenge [10, 11]. As zirconia has a

polycrystalline structure and limited vitreous phase, neither hydrofluoric

acid etching nor silanization can achieve durable zirconia-resin bonding [10,

12]. Thus, various surface treatments have been introduced to establish

durable adhesion between zirconia and dental resin cement.

For chemical bonding, many studies have shown that functional monomers

containing 4-Methacryloyloxyethyl Trimellitate Anhydride (4-META) and

10-Methacryloyloxydecyl Dihydrogen Phosphate (MDP) act as coupling

agents [11, 13, 14]. Moreover, recent studies showed that zirconia primers

and chemically adhesive resin cement have reliable bond strength. [14, 15].

7

For mechanical interlocking, airborne-particle abrasion has been used to

clean the surface, removes impurities, increases surface roughness, and

modify the surface energy and wettability. In addition, airborne-particle

abrasion provides the mechanical impingement of particles on the surface

[16-18], which results in a roughened surface and allows the resin cement to

flow into these micro-retentions and create a stronger micromechanical

interlock [19]. Airborne-particle abrasion with alumina has been identified

as a key factor in achieving a durable bond for zirconia-based ceramics [20-

24]. Different sizes of abrasive alumina particles (25, 50, 115, 125, 150 μm)

have been used, without evidence of the superiority of one over another [10,

11, 13, 25]. However, recent in vitro studies report that airborne-particle

abrasion may have a deleterious effect on the zirconia surface due to the

creation of microcracks, which might reduce the flexural strength [26, 27].

Moreover, the tetragonal phase of Y-TZP is converted to the monoclinic

phase with volume expansion (4 – 5%) under the high stresses caused by

airborne-particle abrasion, and this unique transformation can produce

different types of damage that affect the structural integrity and material

reliability [28]. Specifically, this process may result in an increase in the

crack propagation resistance of Y-TZP for a certain period of time,

functioning as a toughening mechanism [18, 29]. Conversely, since the

presence of the monoclinic structure is unstable and stressful, there is a

higher tendency for the zirconia ceramic in this phase to be fragile. Thus, it

8

may result in an increase in the fracture tendency over the longer term [26,

30, 31]. The counteracting effects of abrasion on the flexural strength of Y-

TZP are controversial in terms of effective power and duration of abrasion,

and the role of surface flaws acting as the stress concentrators relative to the

stress-induced surface compressive layer [26, 32-35].

Although several surface treatments have been recently described [10, 19,

36-40], the selection of the most appropriate airborne-particle abrasion

protocol on for Y-TZP remains controversial. Moreover, no literature

describing the t→m transformation of Y-TZP under various airborne-particle

abrasion could be found. Thus, it is necessary to determine the optimum

protocol for airborne-particle abrasion for monolithic zirconia restoration, in

order to consistently achieve a more favorable clinical outcome.

The purpose of this study was to evaluate several airborne-particle abrasion

protocols and determine how they affect monolithic zirconia in terms of

flexural strength, surface characteristics, and reliability. The shear bond

strength between the abraded monolithic zirconia and resin cement was also

evaluated. The null hypothesis to be tested was that there was no difference

in flexural strength, surface characteristics or shear bond strength of resin

cement before and after thermocycling among groups treated with various

airborne-particle abrasion protocols.

9

2. MATERIAL and METHODS

2. 1. Evaluation of microstructural changes of airborne-particle

abraded monolithic zirconia ceramic

2. 1. 1. Preparation of the specimens

Three-hundreds seventy-five specimens (45 × 4 × 3 mm) of densely sintered

high-purity monolithic zirconia ceramic (Zmatch, Dentaim, Seoul, Korea) –

which consisted of 94 - 95% ZrO2 and HfO2, 5 ± 0.2% Y2O3 and ≤ 0.25%

Al2O3 – were fabricated. The samples, denoted “as-received”, were wet

ground in sequence, first with 300 grit diamond grinding disc and

sequentially with 6, 3 and 1 μm diamond slurry. The grinding and polishing

were performed in order to minimize surface defects on the specimens

before testing.

2. 1. 2. Surface treatment by modifying alumina air abrasion conditions

Bar-shaped specimens were randomly divided into 25 groups (n = 15), and

for each group a different surface treatment was applied to the top surface of

the specimens (Group B to Y). Group A was the control with surface

remaining in the ‘as-received’ state. For alumina particle abrasion,

specimens were mounted in a sample holder at a distance of 10 mm from tip

of the sandblaster unit (AX-B3, AxianMedical Co., Tianjin, China),

equipped with a nozzle of 5 mm in diameter. Specimens were abraded with

10

Fig. 1. Schematic diagram (a) and total specimens (b) of bar-shaped monolithic zirconia specimen for 3-point bending test recommended ISO 6872:2008.

(a)

(b)

11

25, 50 or 125 μm alumina particles (Cobra, Renfert GmbH, Hilzingen,

Germany) at an air pressure of 2 or 4 bar for 10 or 20 seconds. Incidence

angle of particle delivery was maintained at 45 or 90° [41]. Airborne-paricle

abrasion protocols for each group were shown in Table 1.

2. 1. 3. X-ray diffractometry and Raman spectroscopy analysis

Before and after the airborne-particle abrasion, randomly selected

specimens of all groups were examined to analyze the crystalline phases by

X-ray diffractometry (D8 DISCOVER, Bruker, Karlsruhe, Germany). X-ray

diffraction data was collected with 2θ diffractometer using the Cu-Kα

radiation. Diffractogram was obtained from 20° to 40°, at a scan speed of

5°/min and a step size of 0.02° covering the location of the highest peaks of

t and m phases. Refinement of the data was carried out using a graphing

software (Origin 5.0 Professional, Originlab, Northampton, MA, USA). The

monoclinic peak intensity ratio (XM) on the specimen’s surface was

calculated according to the method of Garvie and Nicholson (Eq. 1) [42].

XM = ( ) ( )

( ) ( ) ( ) (Eq. 1)

Im and It represent the integrated intensity (area under the peaks) of the

monoclinic and tetragonal peaks, respectively.

Raman spectra were collected with a triple monochromator spectrometer

12

Table 1. Experimental groups with the various airborne-particle abrasion conditions

Group Size of

particle (μm) Pressure (bar) Time (s) Angle (°)

A (Control) No treatment

B

25

2

10 45

C 10 90

D 20 45

E 20 90

F

4

10 45

G 10 90

H 20 45

I 20 90

J

50

2

10 45

K 10 90

L 20 45

M 20 90

N

4

10 45

O 10 90

P 20 45

Q 20 90

R

125

2

10 45

S 10 90

T 20 45

U 20 90

V

4

10 45

W 10 90

X 20 45

Y 20 90

13

(MonoRa 750i, Dongwoo optron, Kwangju, Korea). The Ar laser (488 nm

wavelength) beam was focused using an optical microscope with ×100 long-

focal objective. Sample exploration and record spectra were performed in

steps of -1 μm [43].

2. 1. 4. Scanning electron microscopy, confocal laser scanning microscopy

and Atomic force microscopy analysis

Randomly selected specimens from all groups were gold-coated with a

sputter coater (SC7620 Mini Sputter Coater, Polaron, Schwalbach, Germany)

and the fractured surfaces were examined using the scanning electron

microscope (FE-SEM, S-4700, HITACHI, Tokyo, Japan) at ×500 and ×5000

magnification. Typical cases were used for illustration.

Confocal laser scanning microscopy (LSM 5 Pascal, Carl Zeiss Microscopy,

Göttingen, Germany) was performed to evaluate surface roughness (Sa) of

the experimental groups. A 543 nm HeNe laser (1 mW) was used as a light

source, and the specimens were examined at ×200 magnification. The

measuring area was 450 × 450 μm, and the height of the z-stack was 30 μm

in 1 μm intervals.

Atomic force microscope (SPA-400, Seiko instruments, Chiba, Japan),

operated in contact mode with 10 μm tip height, no rotation of cone angle

14

and 125 μm cantilever length, was used to obtain a quantitative and

qualitative data. This obtained a 3-dimensional image of the microstructural

surface located in the center of the samples. Images with 256 × 256 pixels

were acquired with a scan size of 20 × 20 μm and a scan rate of 0.65 Hz.

2. 1. 5. Flexural strength test

After the different surface treatments were done, 3-point bending test was

performed at a cross-head speed of 1 mm/min in a universal testing machine

(Model 3345, Instron, Canton, MA, USA) according to the ISO 6872:2008

(Fig. 2). Maximum load to failure was recorded, and the flexural strength

(sf ) was calculated in MPa (Eq. 2).

s =

(Eq. 2)

P is the fracture load (N), l is the span size (30 mm), w is the specimen

width (4 mm) and b is the thickness of the specimen (3 mm).

2. 1. 6. Statistical analysis

Statistical analyses were performed using 4-way ANOVA and Scheffé

multiple comparisons. The 4 factors used for the analyses were particle size,

pressure, time and incidence angle. The overall significance level was set to

α = .05, statistical software (SPSS 20.0; SPSS Inc., Chicago, IL, USA) was

used for calculations.

15

In addition, the strength distributions of quasi-brittle materials like ceramics

are more properly described by Weibull statistics rather than mean strength

values determined based on a Gaussian strength distribution [44]. The

Weibull modulus m was used to assess the variability of strength, where the

smaller m the lower the reliability of strength. The basic form of the Weibull

distribution is shown as follows (Eq. 3) [45, 46].

= 1 − exp − σ

σ

(Eq. 3)

Pf is the probability of failure, σ is the stress applied during testing, and σ0 is

the Weibull characteristic strength which is calculated at 63.21% failure

probability. m is then calculated from the straight line of a slope obtained by

plotting (Eq. 4).

=

σ

σ (Eq. 4)

16

2. 2. Shear bond strength of resin cement

2. 2. 1. Preparation of the specimens

Five-hundreds disc-shaped specimens (ø 9 × 1 mm) were fabricated (Fig. 2a

and 2b) and then sintered in the relevant equipment and equally divided into

25 groups (n = 20). Airborne-particle abrasion protocols were the same as

described in section 2. 1. 2.

2. 2. 2. Bonding procedure

All specimens were ultrasonically cleaned in distilled water for 5 minutes

[47], and were embedded in polytetrafluoroethylene (PTFE) molds (10 mm

in inner diameter, 20 mm in outer diameter, and 11 mm in height) using

polymethyl methacrylate (Vertex-Dental, Dentimex, Zeist, Netherlands),

constructing abraded surface of the disc that remained uncovered for the

resin cement. Commercially available dual-cured resin cement (Panavia F

2.0, Lot no. A paste-00535A and B-paste 00101A, Kuraray Medical Co. Ltd.,

Osaka, Japan) was chosen. A PTFE ring with an opening (3 mm in inner

diameter and 3 mm in depth) was then positioned on the abraded surface of

the specimen. The resin cement was mixed and packed into the PTFE ring

incrementally using hand instrument by the same operator (Fig. 2c) and then

left to polymerize completely for 30 minutes at 23 ± 1 °C after 20 seconds

LED light curing (Elipar™ S10, 3M ESPE, St.Paul, MN, USA). After the

setting, the half of each group (n = 10) was subjected to thermocycling

17

Fig. 2. Schematic diagrams (a) and total specimens (b) of disc-shaped monolithic zirconia specimen. PTFE mold embedded zirconia disc and adhered resin cement (c).

(a)

(b)

(c)

18

for 5000 cycles between 5 and 55 °C. The dwelling time at each temperature

was 30 seconds, and the transfer time from one bath to another was 2

seconds [35]. The remained subgroups (n = 10) were tested after 24 hours

without thermocycling.

2. 2. 3. Shear bond strength test

The specimen was mounted in the jig of a universal testing machine (Model

3345, Instron, Canton, MA, USA) and the shear stress was applied at a

constant crosshead speed of 1 mm/min until fracture between zirconia and

resin cement occurred. Maximum load to failure was recorded, and shear

bond strength was calculated in MPa before and after thermocycling [35].

2. 2. 4. Scanning electron microscopy

Fracture surface of selected specimens was gold coated with a sputter coater

and was examined using SEM (FE-SEM, S-4700, HITACHI, Tokyo, Japan)

at ×30 and ×500 magnification.

2. 2. 5. Statistical analysis

The shear bond strengths were tested with 4–way ANOVA for the

interpretation of the surface treatment differences before and after

thermocycling. The overall significance level was set to α = .05, and a

statistical software (SPSS 20.0, SPSS Inc., Chicago, IL, USA) was used for

calculations.

19

3. RESULTS

3. 1. Microstructural changes of specimens

The flexural strengths of specimens were presented in Fig. 3(a) – 3(g). The

mean strength, characteristic strength (σ0) and Weibull modulus (m) for

experimental groups were listed in Table 2(a) – 2(c). In this study, the mean

flexural strength ranged from 1179 ± 74.1 MPa to 2695 ± 283.1 MPa, the

characteristic strength ranged from 1212 MPa to 2827 MPa, and Weibull

modulus ranged from 7 to 20. The specimens tested in the control group

showed the mean flexural strength for 1454 ± 93.6 MPa, σ0 for 1496MPa

and m for 18. When specimens were abraded with 25 μm alumina particles,

there was significant increase in the flexural strength compared to the

control group. However, with 50 and 125 μm alumina particle, there was no

significant difference. Higher pressure and longer abrasion time increased

the flexural strength with 25 μm particle size; abrasion under 4 bar and 20

seconds significantly increased the strength compared to 2 bar and 10

seconds. However, these tendencies became unclear with other particle sizes.

Weibull moduli were decreased in experimental groups except for Group B

and C.

Table 3 summarized the overall 4-way ANOVA on the flexural strength of

3-point bending test. The 3 main factors (alumina particle size, pressure and

20

Fig. 3(a). The plot of flexural strength against failure probability (%) for Group A specimens “as-received”.

3-point bending fracture strength

Fai

lure

pro

bab

ilit

y (

%)

21

Fig. 3(b). The plot of flexural strength against failure probability (%) for Group B – E specimens with 25 μm alumina particles at 2 bar, variable 10 or 20 s from an angle of 45 or 90°.

Fig. 3(c). The plot of flexural strength against failure probability (%) for Group F – I with 25 μm alumina particles at 4 bar, variable 10 or 20 s from an angle of 45 or 90°.



Fai

lure

pro

bab

ilit

y (

%)

Fai

lure

pro

bab

ilit

y (

%)

22

Fig. 3(d). The plot of flexural strength against failure probability (%) for Group J – M with 50 μm alumina particles at 2 bar, variable 10 or 20 s from an angle of 45 or 90°.

Fig. 3(e). The plot of flexural strength against failure probability (%) for Group N – Q with 50 μm alumina particles at 4 bar, variable 10 or 20 s from an angle of 45 or 90°.



Fai

lure

pro

bab

ilit

y (

%)

Fai

lure

pro

bab

ilit

y (

%)

23

Fig. 3(f). The plot of flexural strength against failure probability (%) for Group R – U with 125 μm alumina particles at 2 bar, variable 10 or 20 s from an angle of 45 or 90°.

Fig. 3(g). The plot of flexural strength against failure probability (%) for Group V – Y with 125 μm alumina particles at 4 bar, variable 10 or 20 s from an angle of 45 or 90°.



Fai

lure

pro

bab

ilit

y (

%)

Fai

lure

pro

bab

ilit

y (

%)

24

Table 2(a). The influence of 25 μm alumina particle size, air stream delivery pressure, application time and incidence angle of particle delivery on the flexural strengths, characteristic strengths, Weibull modulus, monoclinic phase contents and surface roughness

Control Experimental

Size (μm)

As-received

25

Pressure (bar)

2 4

Time (s) 10 20 10 20

Angle (°) 45 90 45 90 45 90 45 90

Group A B C D E F G H I

Mean strength

(MPa)

1454 (93.6)

1245 (72.6)

1179 (74.1)

1498 (207.4)

1597 (165.2)

1725 (218.6)

2047 (274.6)

2695 (283.1)

2554 (215.2)

σ0 (MPa) 1496 1279 1212 1597 1668 1823 2176 2827 2656

m 18 20 18 8 11 9 8 11 14

XM 0 16 22 25 32 26 31 31 32

Sa (μm) 0.07

(0.002) 0.34

(0.007) 0.34

(0.030) 0.33

(0.015) 0.39

(0.022) 0.49

(0.020) 0.54

(0.013) 0.58

(0.031) 0.64

(0.013)

� σ0 = Characteristic strength; m = Weibull modulus; XM = Monoclinic phase contents; Sa = Surface roughness

25

Table 2(b). The influence of 50 μm alumina particle size, air stream delivery pressure, application time and incidence angle of particle delivery on the flexural strengths, characteristic strengths, Weibull modulus, monoclinic phase contents and surface roughness of groups


Experimental

Size (μm) 50

Pressure (bar)

2 4

Time (s) 10 20 10 20

Angle (°) 45 90 45 90 45 90 45 90

Group J K L M N O P Q

Mean strength

(MPa)

1697 (179.0)

1682 (165.5)

1580 (173.8)

1679 (234.6)

1568 (209.8)

1320 (191.1)

1356 (219.9)

1346 (177.1)

σ0 (MPa) 1778 1758 1660 1794 1671 1413 1457 1426

m 11 12 10 8 8 8 7 9

XM 27 37 34 36 29 34 34 37

Sa (μm) 0.44

(0.032) 0.49

(0.007) 0.50

(0.016) 0.62

(0.018) 0.55

(0.017) 0.58

(0.029) 0.61

(0.010) 0.67

(0.037)

26

Table 2(c). The influence of 125 μm alumina particle size, air stream delivery pressure, application time and incidence angle of particle delivery on the flexural strengths, characteristic strengths, Weibull modulus, monoclinic phase contents and surface roughness


Experimental

Size ( μm ) 125

Pressure (bar)

2 4

Time (s) 10 20 10 20

Angle (°) 45 90 45 90 45 90 45 90

Group R S T U V W X Y

Mean strength

(MPa)

1330 (137.9)

1351 (115.9)

1410 (138.8)

1541 (119.8)

1412 (150.5)

1426 (152.1)

1618 (179.0)

1525 (226.3)

σ0 (MPa) 1393 1404 1478 1596 1483 1494 1734 1628

m 11 13 12 15 11 12 11 7

XM 30 33 33 38 35 36 38 40

Sa (μm) 0.44

(0.013) 0.45

(0.019) 0.57

(0.006) 0.58

(0.020) 0.74

(0.013) 0.89

(0.016) 0.84

(0.040) 0.91

(0.055)

27

time) significantly affected the flexural strength, however incidence angle

did not. Interactions were significant except for size × incidence angle,

pressure × incidence angle, and time × incidence angle. The highest strength

were obtained in groups abraded with 25 μm, 4 bar, 20 seconds and 45°

(Group H, σ0 = 2827 MPa).

Fig. 4 presented the Raman spectra obtained in Group U at several depths.

Tetragonal phase was observed with intense peaks at 147, 265 and 320 cm-1.

Conversely, the monoclinic intense peaks at 181 and 190 cm-1 were

observed in the spectra of the most external area. These peaks disappeared

near the 10 μm depth.

The relative monoclinic phases (XM) of each group were summarized in

Table 2 and Fig. 5. XM increased with larger particle size, higher pressure,

longer time and larger incidence angle except for Group K, ranged from 0%

(control group) and 16% (Group B) to 40% (Group Y). The X-ray

diffraction spectra of control group and experimental Group Y, the latter

having the highest monoclinic contents among the experimental groups,

were shown in Fig. 6(a) – 6(b). The XM values were 0% and 40%,

respectively. Group A spectrum only has one t peak at 30.2°, while m peaks

were shown at both sides of reduced and broadened t peak in Group Y

spectrum. These results confirmed that the observed asymmetry in the

28

Table 3. Summary of 4-way ANOVA for flexural strength conducted at each level of interacting factor

Source Sum of

Square df

Mean

Square F P

Size 8702236.7 2 4351118.4 131.6 .000

Pressure 4848104.8 1 4848104.8 146.6 .000

Time 3724864.3 1 3724864.3 112.6 .000

Angle 11211.3 1 11211.3 .3 .561

Size × Pressure 20677986.9 2 10338993.5 312.7 .000

Size × Time 5909509.0 2 2954754.5 89.4 .000

Size × Angle 108795.1 2 54397.6 1.6 .194

Pressure × Time 353001.5 1 353001.5 10.7 .001

Pressure × Angle 126075.5 1 126075.5 3.8 .052

Time × Angle 3900.6 1 3900.6 .1 .731

Size × Pressure × Time 904131.4 2 452065.7 13.7 .000

Size × Pressure × Angle 257834.3 2 128917.2 3.9 .021

Size × Time × Angle 457854.7 2 228927.4 6.9 .001

Pressure × Time × Angle 348755.6 1 348755.6 10.5 .001

Size × Pressure × Time × Angle 588903.8 2 294451.9 8.9 .000

Error 11573738.0 350 33067.8

Total 1012104439.0 375

29

Fig. 4. Raman spectra obtained in Group U at several depths. The monoclinic doublets at 181 – 190 cm-1 were evident in the spectra of the most external area, but closer to surface.

30

Fig. 5. Monoclinic contents of each group after airborne-particle abrasion.

Group

Mo

nocl

inic

phas

e co

nte

nts

(%

)

31

spectrum of Group Y was due to the concentrated stress in the region of

abraded surface. Fig. 6(c) showed the spectra of Group B, J and R

specimens, which presented the effect of alumina particle size. The XM

values were 16%, 27% and 30%, respectively. A decrease and broadness in

the intensity of t peak was observed when the size of alumina particles

increased from 25 to 125 μm, thus meaning the increase of the XM values.

Fig. 6(d) showed the spectra of Group M, N, O and Q. Group M and Q

showed the effect of pressure, Group N and O showed the effect of

incidence angle, and Group O and Q showed the effect of time. Pressure,

time and incidence angle had increasing effects on t→m transformation. The

XM values of Group M, N, O and Q were 36%, 29%, 34% and 37%,

respectively.

The surface roughness values (Sa) measured by confocal laser scanning

microscopy were presented in Table 2. These data suggested that the

interaction of different size of particle, pressure, time and angle promoted

different topograghic patterns on the monolithic zirconia ceramic surfaces.

The representative surface images showing differences of surfaces could be

observed from the reconstructed 3D images of Group A, B and Y in Fig. 7(a)

– 7(c). Mean surface roughness of specimens abraded with alumina particle

ranged from 0.33 ± 0.015 μm to 0.91 ± 0.055 μm. The control group (Fig.

7a) had the mean Sa of 0.07 ± 0.002 μm, while Group B had the smallest

32

Fig. 6(a). X-ray diffraction patterns obtained from Group A. Group A spectrum only has one t peak at 30.2°, and no m peak around 29° and 31° was observed.

Fig. 6(b). X-ray diffraction patterns obtained from Group Y. Group Y spectrum shows the m peaks around 29° and 31° and the broadened t peak.

t

m m

2θ (degree)

Inte

nsi

ty

Inte

nsi

ty

2θ (degree)

t

33

Fig. 6(c). X-ray diffraction patterns obtained from Group B, J and R.

t

m m

Inte

nsi

ty

2θ (degree)

34

Fig. 6(d). X-ray diffraction patterns obtained from Group M, N, O and Q which were abraded with 50 μm alumina particles.

m m

t

Inte

nsi

ty

2θ (degree)

35

Fig. 7. The representative confocal laser scanning microscopy images of the selected groups. (a) Control group; (b) the smallest Sa value among abraded groups – Group B; (c) the highest Sa value among abraded groups – Group Y.

36

value of 0.34 ± 0.007 μm and Group Y had the highest value of 0.91 ± 0.055

μm (Fig. 7c). The mean Sa values increased with larger particle size, higher

pressure, longer time, larger incidence angle except for Group B and C

(Both Sa = 0.34 μm).

Microscopic examination revealed the change of the topographic surfaces of

monolithic zirconia ceramics after airborne-particle abrasion with alumina

(Fig. 8). After airborne-particle abrasion with different particle sizes of

alumina, scanning electron microscopy observations revealed an increase in

surface roughness in accordance with the increase of Sa value. In control

group, no micro-retentive pattern could be detected (Fig. 8a and 8b). After

airborne-particle abrasion with 25 μm, the smooth surface was roughened

and polished pattern was no longer seen (Fig. 8c and 8d). This treatment

produced a coarse surface with grooves and sharp edges. With particle size

of 125 μm, strong abrasion conditions created a similar but more roughened

surface (Fig. 8e and 8f).

Fig. 9 shows the microstructural surface image of Group L obtained by

atomic force microscopy which exhibits the erosive wear facet and focal

surface profile. The ‘as-received’ surface of control group is shown in Fig.

10a, which exhibited a few small spikes. Fig. 10b shows the engraved

surface after abrasion with 125 μm, 4 bar, 20 seconds and 90° (Group Y).

37

Fig. 8. Scanning electron micrographs (the left sides magnification ×500 and the right sides ×5000) of zirconia surfaces; (a, b) Control group; (c, d) Group B which had the smallest mean Sa value; (e, f) Group Y which had the highest mean Sa value. The mean Sa values were 0.07 ± 0.002 μm, 0.34 ± 0.007 μm and 0.91 ± 0.055 μm, respectively.

38

Fig. 9. Alumina-abraded nanostructural image of erosive wear facet observed by atomic force microscopy, representative image of Group L.

Fig. 10. Representative microstructural images by atomic force microscopy. (a) Control group; (b) Group Y. Control group had the maximum height of 190.08 nm, but Group Y had the maximum height of 3262.85 nm.

39

3. 2. Shear bond strength of resin cement

3. 2. 1. Shear bond strength and effect of thermocycling

The mean and standard deviations of the shear bond strength in all groups

were listed in Table 4 and illustrated in Fig. 11(a)-11(c). Table 5 and Table 6

summarized the overall 4-factor ANOVA on the shear bond strength before

and after thermocycling. In this study, the mean shear bond strength of resin

cement ranged from 10.8 ± 2.52 MPa to 18.3 ± 3.64 MPa before

thermocycling and from 6.1 ± 2.84 MPa to 12.7 ± 3.38 MPa after

thermocycling. The control group showed the mean shear bond strength of

6.7 ± 1.92 MPa before thermocycling and 3.0 ± 1.12 MPa after

thermocycling. Airborne-particle abrasion significantly increased the bond

strength, while thermocycling decreased the bond strength of resin cement.

In thermocycling groups, strong shear bond strengths were observed in

groups abraded with 50 μm, 4 bar, 20 seconds in both 45° and 90° (Group P

and Q). On the other hand, weak shear bond strengths were observed in

groups abraded with 125 μm, 2 bar and 10 seconds in both angles (Group R

and S). Groups abraded with 50 μm exhibited significantly higher values on

a similar surface roughness level measured with 25 or 125 μm. The 3 main

factors (alumina particle size, pressure and time) affected the bond strength

with resin cement, however incidence angle did not.

40

Table 4. Means and standard deviations in parenthesis of the shear bond strength (MPa) of resin cement investigated before and after thermocycling

Group 0 thermocycles 5000 thermocycles

A (Control) 6.7 (1.92) 3.0 (1.12)

B 11.3 (3.73) 6.9 (3.56)

C 11.6 (2.77) 8.3 (2.36)

D 12.8 (1.76) 8.5 (3.87)

E 13.3 (4.42) 8.4 (2.07)

F 11.8 (3.40) 8.6 (2.57)

G 11.7 (1.62) 8.8 (2.97)

H 14.8 (2.46) 9.4 (2.80)

I 12.7 (3.44) 8.9 (2.62)

J 13.7 (3.88) 12.1 (2.57)

K 12.2 (2.12) 11.3 (2.61)

L 14.7 (3.94) 10.3 (2.07)

M 15.3 (3.13) 11.4 (2.82)

N 15.5 (2.08) 10.4 (2.56)

O 15.3 (3.78) 11.1 (2.28)

P 18.1 (4.41) 12.6 (3.73)

Q 18.3 (3.64) 12.7 (3.38)

R 10.8 (2.52) 6.1 (2.84)

S 10.8 (3.16) 6.2 (1.36)

T 11.3 (0.56) 10.6 (3.51)

U 12.0 (1.99) 11.1 (3.71)

V 12.0 (3.70) 9.4 (2.82)

W 11.5 (0.61) 10.4 (2.89)

X 12.6 (3.69) 9.9 (2.39)

Y 12.1 (2.07) 9.8 (2.52)

41

Fig. 11(a). Box-plot diagram comprising the shear bond strengths (MPa) of control group and groups abraded with 25 μm.

Group

Str

ength

(M

Pa)

42

Fig. 11(b). Box-plot diagram comprising the shear bond strengths (MPa) of control group and groups abraded with 50 μm.

Group

Str

ength

(M

Pa)

43

Fig. 11(c). Box-plot diagram comprising the shear bond strengths (MPa) of control group and groups abraded with 125 μm.

Group

Str

ength

(M

Pa)

44

Table 5. Summary of 4-way ANOVA for the shear bond strength before thermocycling conducted at each level of interacting factor

Source Sum of Square

Df Mean

Square F P

Size 613.7 2 306.9 37.7 .000

Pressure 114.8 1 114.8 14.1 .000

Time 164.0 1 164.0 20.2 .000

Angle 2.9 1 2.9 0.4 .551

Size × Pressure 62.0 2 31.0 3.8 .024

Size × Time 30.0 2 14.8 1.8 .165

Size × Angle 0.7 2 0.4 - .956

Pressure × Time 1.4 1 1.4 0.2 .677

Pressure × Angle 6.7 1 6.7 0.8 .366

Time × Angle 1.0 1 1.0 0.1 .724



Size × Time × Angle 12.7 2 6.3 0.8 .461


Size × Pressure × Time ×

Angle 2.0 2 1.0 0.1

.885

Error 1,830.3 225 8.1

Total 44,994.2 250

45

Table 6. Summary of 4-way ANOVA for the shear bond strength after thermocycling conducted at each level of interacting factor

Source Sum of Square

Df Mean

Square F P

Size 405.3 2 202.7 29.0 .000

Pressure 49.1 1 49.1 7.1 .008

Time 81.4 1 81.4 11.7 .001

Angle 5.3 1 5.3 0.8 .382

Size × Pressure 9.4 2 4.7 0.7 .510

Size × Time 40.8 2 20.4 2.9 .055

Size × Angle 0.5 2 0.2 - .968

Pressure × Time 9.2 1 9.2 1.3 .252

Pressure × Angle 0.4 1 0.4 0.1 .818

Time × Angle 1.1 1 1.1 0.2 .685



Size × Time × Angle 7.9 2 3.9 0.6 .570


Size × Pressure × Time ×

Angle 7.2 2 3.6 0.5

.597

Error 1,568.1 225 7.0

Total 15,106.4 250

46

Interaction of alumina particle size × pressure significantly affected the

shear bond strength before thermocycling, and interaction of particle size ×

pressure × time was statistically significant after thermocycling. This

finding meant that there was a certain combination of particle size ×

pressure × time for creating higher shear bond strength after aging treatment

process. Based on this study, these combinations were 50 μm, 4 bar and 20

seconds regardless of incidence angle.

Fig. 12 showed the representative SEM images of the fractured interfaces in

control group, Group R and Group Q, having the shear bond strengths of 3.0

± 1.12 MPa, 6.9 ± 3.56 MPa and 12.7 ± 3.38 MPa, respectively. In control

group (Fig. 12a and 12b), there were no remnant of resin cement on the

fractured surface. Group R (Fig. 12c and 12d), which had the lowest shear

bond strength (6.9 ± 3.56 MPa), showed adhesive failure mode at

zirconia/cement interface. Group Q (Fig. 12e and 12f), which had the

highest shear bond strength (12.7 ± 3.38 MPa), exhibited adhesive failure

mode with more remnants of the resin cement on zirconia surface.

47

Fig. 12. Scanning electron micrograghs (the left sides magnification ×30 and the right sides ×500) of zirconia surfaces; (a, b) Control group; (c, d) Group R which had the lowest shear bond strength to resin cement; (e, f) Group Q which had the highest shear bond strength to resin cement. The mean strength values after thermocycling were 3.0 ± 1.12 MPa, 6.9 ± 3.56 MPa and 12.7 ± 3.38 MPa, respectively.

48

4. DISCUSSION

The current investigation revealed a significant effect of several alumina

airborne-particle abrasion protocols on the flexural strength and

characteristics of monolithic zirconia ceramics. The flexural strength was

increased with higher pressure and longer time but was unaffected by the

incidence angle. In addition, the 2-way interactions containing the incidence

angle factor were all insignificant. However, the 3-way interaction and 4-

way interaction containing incidence angle factor were significant. This

means that the incidence angle factor is only significant in terms of the how

it affects the differences in the effects between other parameters. The

alumina particle size of 25 μm significantly increased the flexural strength,

while specimens treated with particle sizes of 50 and 125 μm were not

statistically different from the control group. The surface roughness,

transformed monoclinic contents and concentrated stress during airborne-

particle abrasion may have effects on the flexural strength of the monolithic

zirconia ceramics through multiple mechanisms. Therefore, the null

hypothesis that there is no difference in the flexural strength and

characteristics by modifying alumina airborne-particle abrasion protocols on

monolithic zirconia was rejected. In addition, the shear bond strength of the

alumina airborne-particle abraded monolithic zirconia surface after

thermocycling was significantly higher than that of the ‘as-received’

49

specimen. These results support the rejection of the null hypothesis that

shear bond strength of resin cement to the abraded monolithic zirconia

surface would not be different from that to a ‘as-received’ one, and that

thermocycling does not affect shear bond strength of resin cement to the

abraded surface.

In this study, airborne-particle abrasion provided a powerful method for

improvement of both flexural strength and bond strength of resin cement at

the cost of a somewhat lower degree of reliability. According to Kosmac et

al. [16], this finding is likely explained by considering two competing

factors influencing the strength of surface-treated Y-TZP ceramics. One is

residual surface compressive stresses which contribute to strengthening, and

the other is the mechanically-induced surface flaws which cause strength

degradation. Compressive stresses are formed due to t→m transformation,

which increase the flexural strength of zirconia ceramics by resisting crack

propagation [2, 16, 33, 34]. However, under clinical conditions where the

material is exposed to thermal and mechanical cycling in an aqueous

environment over long periods, fracture initiation at lower levels of applied

stress is enhanced [16]. The amount of tetragonal phase that is able to

transform to monoclinic under compression is one of the main features of

zirconia ceramics, because this determines the fracture toughness [48].

50

The variability in strength of ceramics is primarily due to the extreme

sensitivity to the presence of cracks of different sizes [49]. For a given

ceramic material, the distribution of crack size, shape, and orientation

differs from sample to sample. Thus, Weibull proposed two parameter

distribution functions to characterize the strength of brittle materials and the

Weibull distribution function is widely used to model or characterize the

flexural strength of various brittle materials including dental ceramics [44,

45, 49]. Strength variability is usually characterized using the Weibull

distribution, which is based on the premise that the weakest link in a body

determines to overall strength. It is also well described [45, 46] that such

measured strength changes due to differences in test specimen size and

configuration can be quantitatively predicted using Weibull parameters. The

distribution function relates the cumulative probability of failure under

stress to two parameters, the Weibull modulus (m) and the Weibull

characteristic strength (σ0). The Weibull modulus describes the relative

spread of strength values in the asymmetrical distribution, with high m

corresponding to less spread. On the other hands, a large value of Weibull

modulus ensures a smaller variability in strength estimation [44, 50, 51].

Large ranges of flexural strength and Weibull modulus values for zirconia

ceramics have been reported in the literature. For Y-TZP, the flexural

strength varies from 700 to 1200 MPa and the Weibull modulus from 10 to

18 [16, 18, 50, 52, 53].

51

In this study, the mean values of the monolithic zirconia characteristic

strength ranged from 1212 to 2827 MPa, and Weibull modulus from 7 to 20.

There were significant effects of airborne-particle size, notably the 25 and

50 μm particle sizes, on the flexural strength and Weibull characteristic

strength, which generally also resulted in a decrease in reliability in all but

two groups (Groups B and C). Interestingly, an increase in particle size (125

μm) produced a decrease in the flexural strength data and reliability (Table

2). Due to high stresses developed during abrasion with 125 μm particle size,

severe surface cracks were formed which likely reduced the strength and

reliability of the material [16, 54]. The effect of the large-sized particles on

the zirconia specimen may produce unstable flaws or substrate damage with

microcracks.

Low particle velocity with small size, low pressure and low angle has a

reduced rate of surface erosion [41], and hence it would appear that particles

at 45° are more likely to safely abrade brittle substrates in combination with

a low air stream pressure. At low velocity and relatively smaller particle

sizes (25 and 50 μm), a significant increase in Weibull modulus and

characteristic strength, representing an improvement in the reliability of the

flexural strength data, was observed with a decrease in the incidence angle,

whereas at high velocity and a 125 μm particle size, a decrease in the

Weibull modulus and characteristic strength of the specimens was observed.

52

When an abrasive particle is pressed against the surface of the monolithic

zirconia specimen, a contact stress field is generated which, for the various

airborne-particle abrasion protocols used here, was able to reach a

magnitude sufficient to induce the t→m transformation up to a depth of 10

μm, as shown in Fig. 4. In X-ray diffraction data, the amount of monoclinic

phase (XM) was increased with larger particle size, higher pressure, longer

time and larger incidence angle. This is consistent with various in vitro

studies which have shown that the amount of monoclinic phase produced

varied according to these four factors [17, 35, 40]. Interestingly, in this study,

the incidence angles factor took precedence over time factor in certain

groups (Groups G and H, Groups K and L, Groups O and P, Groups S and

T). Except the weakest conditions (Groups C and D) and the strongest

conditions (Groups W and X), the same trends for variation in the incidence

angle were shown over time under the same pressure conditions throughout

the X-ray diffraction spectra. In addition, the combination of the incidence

angle and the abrading time seemed more important than pressure in m

transformation phase. All groups with protocols that included 2 bar, 20

seconds and 90° parameters exhibited higher XM than those with protocols

that called for 4 bar, 10 seconds and 45°.

Sa data in our study suggest that the interaction of different size of particle,

pressure, time and angle promote different topographic patterns on the

53

monolithic zirconia ceramic surfaces. It is noteworthy that surface

roughness of groups with 10 seconds and 90° was similar to that of groups

with 20 seconds and 45° at the same pressure, and that the relative

monoclinic phase contents were similar in both groups. It is possible that

lower particle velocity may cause smaller surface fragments to be broken

thereby increasing surface roughness without introducing more detrimental

defects in spite of longer abrading time. With smaller particle sizes, it will

then be favorable to either increase the incidence angle and shorten the

abrading time or decrease the angle and extend the abrading time. When 125

μm-sized alumina was employed, the surface roughness (Sa) value increased

reflecting the relative “chipping” phenomenon at the zirconia surface.

Various in vitro studies have shown that airborne-particle abrasion with

alumina is an essential step in achieving a durable bond to high strength

ceramics [10, 13, 14, 26]. However, despite the increase in bond strength

between the resin cement and zirconia ceramics, the application of airborne-

particle abrasion on such ceramics is controversial due to the possible

introduction of flaws and microcracks [55, 56]. As expected, the application

of airborne-particle abrasion to monolithic zirconia specimens resulted in a

significant increase in shear bond strength, as observed in the values of

shear bond strength in both pre- and post-thermocycled specimens’

compared to the ‘as-received’ monolithic zirconia specimens. In bonding

54

with resin cement after thermocycling, the highest shear bond strength was

observed in groups abraded with 50 μm particles, whereas the lowest shear

bond strength in groups abraded with 125 μm. In other words, groups

abraded with 125 μm exhibited significantly lower shear bond strength

compared to the 50 μm abrasion-groups, despite having similar surface

roughness levels.

The difference in shear bond strength values of the two groups decreased

after thermocycling. This finding suggested that thermocycling significantly

reduces the shear bond strength regardless of alumina particle size in

airborne-particle abrasion. This result is in accordance with other studies

showing the relative insignificance of the particle size difference in abrasion

when the outcome of interest is the production of a durable bond between

Y-TZP and resin cement [10, 25, 57]. Moreover, these results indicate that,

while airborne-particle abrasion of monolithic zirconia produces superficial

irregularities corresponding to the certain abrasion protocol, the effect of

severe-sized undercuts is limited considering its contribution to the increase

of surface roughness. Ultimately, the recommended mean size of alumina

particle is 50 μm considering its ideal contribution to surface roughness and

monoclinic phase, providing optimal shear bond strength, and its cleaning

effect on the inner surface of restorations.

55

In this study, shear bond strengths were significantly decreased regardless of

the size of alumina particle for surface treatment after 5,000 thermocycles.

Interaction of particle size × pressure × time was not significant before

thermocycling; however, it became statistically significant after

thermocycling. This change may suggest that the interaction of the three

factors (particle size, pressure, time) maintains the long-term resin bond

strength of monolithic zirconia ceramics [57].

In short, the interaction between the abrasive particle and the substrate

surface clearly relies on complex interactions and cannot be explained by a

simple theoretical model. The alteration of the flaw population of the

specimen is often indiscriminate but may have dramatic effects on the

longevity of a restoration. Airborne-particle abrasion with alumina increases

the monolithic zirconia surface area and increases the surface area allowed,

to an even greater extent, for the reaction between the resin cement and

zirconia ceramics. This study suggests that airborne-particle abrasion with

mean particle size of 50 μm, 4 bars and 20 seconds in both angles of

incidence is effective for reliability of monolithic zirconia ceramics and for

strong and durable bond formation with resin cement.

This study is not without limitation; this study did not include a group with

a longer artificial aging time or comparison with other resin cements

56

containing different functional monomers, which could have affected the

bond strength of the monolithic zirconia ceramics. Such data would be

beneficial for estimating the long-term prognosis for monolithic zirconia

restoration. Further studies to determine how to reduce the monoclinic phase

and experiments using crown-shaped specimens of monolithic zirconia

ceramic are needed.

57

5. CONCLUSIONS

Airborne-particle abrasion with alumina modifies the initial flaw

distribution and transforms the crystal phase which affects the stability of

monolithic zirconia ceramics, and increases the shear bond strength with

resin cement. The recommended protocol based on this study is airborne-

particle abrasion with 50 μm alumina particles, 4 bar of pressure, and 20

seconds of application time either 45° or 90° incidence angles.

58

[1] Pjetursson BE, Sailer I, Zwahlen M, Hammerle CH. A systematic review of the survival and complication rates of all-ceramic and metal-ceramic reconstructions after an observation period of at least 3 years. Part I: Single crowns. Clin Oral Impl Res 2007;18 Suppl 3:73-85.

[2] Luthardt RG, Holzhuter M, Sandkuhl O, Herold V, Schnapp JD, Kuhlisch E, Walter M. Reliability and properties of ground Y-TZP-zirconia ceramics. J Dent Res 2002;81:487-91.

[3] Ernst CP, Doz P, Cohnen U, Stender E, Willershausen B. In vitro retentive strength of zirconium oxide ceramic crowns using different luting agents. J Prosthet Dent 2005;93:551-8.

[4] Larsson C, Vult von Steyern P. Five-year follow-up of implant-supported Y-TZP and ZTA fixed dental prostheses. A randomized, prospective clinical trial comparing two different material systems. Int J Prosthodont 2010;23:555-61.

[5] Sailer I, Feher A, Filser F, Luthy H, Gauckler LJ, Scharer P, Hammerle CH. Prospective clinical study of zirconia posterior fixed partial dentures: 3-year follow-up. Quintessence Int 2006;37:685-93.

[6] Tinschert J, Schulze KA, Natt G, Latzke P, Heussen N, Spiekermann H. Clinical behavior of zirconia-based fixed partial dentures made of DC-Zirkon: 3-year results. Int J Prosthodont 2008;21:217-22.

[7] Rojas-Vizcaya F. Full Zirconia Fixed Detachable Implant-Retained Restorations Manufactured from Monolithic Zirconia: Clinical Report after Two Years in Service. J Prosthodont 2011;20:570-6.

[8] Preis V, Behr M, Hahnel S, Handel G, Rosentritt M. In vitro failure and fracture resistance of veneered and full-contour zirconia restorations. J Dent 2012;40:921-8.

[9] Beuer F, Stimmelmayr M, Gueth JF, Edelhoff D, Naumann M. In vitro performance of full-contour zirconia single crowns. Dent Mater 2012;28:449-56.

[10] Kern M, Wegner SM. Bonding to zirconia ceramic: adhesion methods and their durability. Dent Mater 1998;14:64-71.

[11] Blatz MB, Sadan A, Kern M. Resin-ceramic bonding: a review of the literature. J Prosthet Dent 2003;89:268-74.

[12] Janda R, Roulet JF, Wulf M, Tiller HJ. A new adhesive technology for all-ceramics. Dent Mater 2003;19:567-73.

[13] Hummel M, Kern M. Durability of the resin bond strength to the alumina ceramic Procera. Dent Mater 2004;20:498-508.

REFERENCES

59

[14] Blatz MB, Sadan A, Martin J, Lang B. In vitro evaluation of shear bond strengths of resin to densely-sintered high-purity zirconium-oxide ceramic after long-term storage and thermal cycling. J Prosthet Dent 2004;91:356-62.

[15] Lüthy H, Loeffel O, Hammerle CHF. Effect of thermocycling on bond strength of luting cements to zirconia ceramic. Dent Mater 2006;22:195-200.

[16] Kosmac T, Oblak C, Jevnikar P, Funduk N, Marion L. The effect of surface grinding and sandblasting on flexural strength and reliability of Y-TZP zirconia ceramic. Dent Mater 1999;15:426-33.

[17] Sato H, Yamada K, Pezzotti G, Nawa M, Ban S. Mechanical properties of dental zirconia ceramics changed with sandblasting and heat treatment. Dent Mater J 2008;27:408-14.

[18] Curtis AR, Wright AJ, Fleming GJ. The influence of surface modification techniques on the performance of a Y-TZP dental ceramic. J Dent 2006;34:195-206.

[19] Senyilmaz DP, Palin WM, Shortall AC, Burke FJ. The effect of surface preparation and luting agent on bond strength to a zirconium-based ceramic. Oper Dent 2007;32:623-30.

[20] Al-Dohan HM, Yaman P, Dennison JB, Razzoog ME, Lang BR. Shear strength of core-veneer interface in bi-layered ceramics. J Prosthet Dent 2004;91:349-55.

[21] Oh WS, Shen C. Effect of surface topography on the bond strength of a composite to three different types of ceramic. J Prosthet Dent 2003;90:241-6.

[22] Valandro LF, Ozcan M, Bottino MC, Bottino MA, Scotti R, Bona AD. Bond strength of a resin cement to high-alumina and zirconia-reinforced ceramics: the effect of surface conditioning. J Adhes Dent 2006;8:175-81.

[23] Awliya W, Oden A, Yaman P, Dennison JB, Razzoog ME. Shear bond strength of a resin cement to densely sintered high-purity alumina with various surface conditions. Acta Odontol Scand 1998;56:9-13.

[24] Derand P, Derand T. Bond strength of luting cements to zirconium oxide ceramics. Int J Prosthodont 2000;13:131-5.

[25] Tsuo Y, Yoshida K, Atsuta M. Effects of alumina-blasting and adhesive primers on bonding between resin luting agent and zirconia ceramics. Dent Mater J 2006;25:669-74.

[26] Zhang Y, Lawn BR, Rekow ED, Thompson VP. Effect of sandblasting on the long-term performance of dental ceramics. J Biomed Mater Res B. Appl Biomater 2004;71:381-6.

[27] Zhang Y, Lawn BR, Malament KA, Van Thompson P, Rekow ED. Damage accumulation and fatigue life of particle-abraded ceramics. Int J Prosthodont 2006;19:442-8.

60

[28] Gupta TK. Strengthening by Surface Damage in Metastable Tetragonal Zirconia. J Am Ceram Soc 1980;63:117.

[29] Casucci A, Osorio E, Osorio R, Monticelli F, Toledano M, Mazzitelli C, Ferrari M. Influence of different surface treatments on surface zirconia frameworks. J Dent 2009;37:891-7.

[30] Christel P, Meunier A, Heller M, Torre JP, Peille CN. Mechanical properties and short-term in-vivo evaluation of yttrium-oxide-partially-stabilized zirconia. J Biomed Mater Res 1989;23:45-61.

[31] Sato T, Shimada M. Transformation of yttria-doped tetragonal ZrO2 polycrystals by annealing in water. J Am Ceram Soc 1985;68:356-9.

[32] Green DJ. A technique for introducing surface compression into zirconia ceramics. J Am Ceram Soc 1983;66:C178-C9.

[33] Kosmac T, Oblak C, Jevnikar P, Funduk N, Marion L. Strength and reliability of surface treated Y-TZP dental ceramics. J Biomed Mater Res 2000;53:304-13.

[34] Guazzato M, Quach L, Albakry M, Swain MV. Influence of surface and heat treatments on the flexural strength of Y-TZP dental ceramic. J Dent 2005;33:9-18.

[35] Moon JE, Kim SH, Lee JB, Ha SR, Choi YS. The effect of preparation order on the crystal structure of yttria-stabilized tetragonal zirconia polycrystal and the shear bond strength of dental resin cements. Dent Mater 2011;27:651-63.

[36] Della Bona A, Donassollo TA, Demarco FF, Barrett AA, Mecholsky JJ, Jr. Characterization and surface treatment effects on topography of a glass-infiltrated alumina/zirconia-reinforced ceramic. Dent Mater 2007;23:769-75.

[37] Oyague RC, Monticelli F, Toledano M, Osorio E, Ferrari M, Osorio R. Effect of water aging on microtensile bond strength of dual-cured resin cements to pre-treated sintered zirconium-oxide ceramics. Dent Mater 2009;25:392-9.

[38] Oyague RC, Monticelli F, Toledano M, Osorio E, Ferrari M, Osorio R. Influence of surface treatments and resin cement selection on bonding to densely-sintered zirconium-oxide ceramic. Dent Mater 2009;25:172-9.

[39] Uo M, Sjogren G, Sundh A, Goto M, Watari F, Bergman M. Effect of surface condition of dental zirconia ceramic (Denzir) on bonding. Dent Mater J 2006;25:626-31.

[40] Hallmann L, Ulmer P, Reusser E, Hammerle CH. Surface characterization of dental Y-TZP ceramic after air abrasion treatment. J Dent 2012;40:723-35.

[41] Addison O, Marquis PM, Fleming GJ. The impact of modifying alumina air abrasion parameters on the fracture strength of a porcelain laminate restorative material. Dent Mater 2007;23:1332-41.

61

[42] Garvie RC. Phase analysis in zirconia systems. J Am Ceram Soc 1972;55:303-5.

[43] Munoz-Tabares JA, Jimenez-Pique E, Reyes-Gasga J, Anglada M. Microstructural changes in ground 3Y-TZP and their effect on mechanical properties. Acta Mater 2011;59:6670-83.

[44] Weibull W. A statistical distribution function of wide applicability. J Appl Mech-T Asme 1951;18:293-7.

[45] Ritter JE. Predicting lifetimes of materials and material structures. Dent Mater 1995;11:142-6.

[46] Quinn JB, Quinn GD. A practical and systematic review of Weibull statistics for reporting strengths of dental materials. Dent Mater 2010;26:135-47.

[47] Yun JY, Ha SR, Lee JB, Kim SH. Effect of sandblasting and various metal primers on the shear bond strength of resin cement to Y-TZP ceramic. Dent Mater 2010;26:650-8.

[48] Juy A, Anglada M. Surface phase transformation during grinding of Y-TZP. J Am Ceram Soc 2007;90:2618-21.

[49] Basu B, Tiwari D, Kundu D, Prasad R. Is Weibull distribution the most appropriate statistical strength distribution for brittle materials? Ceram Int 2009;35:237-46

[50] Tinschert J, Natt G, Mohrbotter N, Spiekermann H, Schulze KA. Lifetime of alumina- and zirconia ceramics used for crown and bridge restorations. J Biomed Mater Res B Appl Biomater 2007;80B:317-21

[51] Thompson GA. Determining the slow crack growth parameter and Weibull two-parameter estimates of bilaminate disks by constant displacement-rate flexural testing. Dent Mater 2004;20:51-62.

[52] Lin WS, Ercoli C, Feng C, Morton D. The effect of core material, veneering porcelain, and fabrication technique on the biaxial flexural strength and weibull analysis of selected dental ceramics. J Prosthodont 2012;21:353-62.

[53] Luthardt RG, Holzhüter MS, Rudolph H, Herold V, Walter MH. CAD/CAM-machining effects on Y-TZP zirconia. Dent Mater 2004;20:655-62.

[54] Wang H, Aboushelib MN, Feilzer AJ. Strength influencing variables on CAD/CAM zirconia frameworks. Dent Mater 2008;24:633-8.

[55] Wegner SM, Gerdes W, Kern M. Effect of different artificial aging conditions on ceramic-composite bond strength. Int J Prosthodont 2002;15:267-72.

[56] Atsu SS, Kilicarslan MA, Kucukesmen HC, Aka PS. Effect of zirconium-oxide ceramic surface treatments on the bond strength to adhesive resin. J Prosthet Dent 2006;95:430-6.

[57] Phark JH, Duarte S, Jr., Blatz M, Sadan A. An in vitro evaluation of the long-term resin bond to a new densely sintered high-purity zirconium-oxide ceramic surface. J Prosthet Dent 2009;101:29-38.

APPENDIX

2

1. Raw data of fracture strengths (MPa) by 3-point bending test

No. Group

A B C D E F G H I

1 1314 1103 1226 1627 1624 1604 1959 2809 3000

2 1321 1254 1252 1408 1265 1516 1403 2722 2451

3 1349 1303 1239 1388 1678 2038 2109 2688 2194

4 1363 1217 1237 1459 1647 1550 1833 2697 2510

5 1412 1251 1100 1557 1727 1532 2116 3120 2490

6 1420 1153 1059 1477 1787 1503 2063 2532 2615

7 1432 1241 1047 1378 1325 1800 1842 2564 2765

8 1446 1353 1148 1352 1441 1725 2029 2419 2571

9 1459 1342 1101 1834 1532 1642 2014 3012 2461

10 1483 1211 1262 1749 1781 1869 1954 2889 2329

11 1536 1220 1150 1823 1453 1966 2434 2811 2558

12 1536 1203 1213 1485 1543 2070 1822 2357 2364

13 1559 1201 1165 1016 1789 1846 2390 2889 2470

14 1568 1264 1262 1396 1712 1340 2339 2016 2942

15 1610 1363 1215 1525 1589 1874 2397 2904 2592

Mean 1454 1245 1178 1498 1593 1725 2047 2695 2554

SD 94 73 74 207 165 219 275 283 215

3

No. Group

J K L M N O P Q

1 1918 1831 1405 1629 1573 1198 1397 1555

2 1922 1828 1689 1961 1390 1495 1166 1569

3 1558 1465 1524 1393 1419 1259 1764 1646

4 1706 1629 1540 1557 1548 1072 1395 1171

5 1607 1547 1754 1426 2047 1131 1187 1183

6 1759 1555 1766 2090 1622 1256 1655 1341

7 2075 1768 1510 1552 1985 1264 1285 1253

8 1726 1539 1700 1601 1350 1176 1295 1257

9 1550 1749 1510 1545 1449 1207 1137 1483

10 1798 1545 1662 1894 1629 1281 1715 1528

11 1529 1826 1458 2167 1405 1279 1555 1250

12 1776 1725 1983 1557 1722 1720 1089 1100

13 1482 2047 1393 1564 1400 1675 1261 1216

14 1526 1464 1371 1634 1470 1506 1287 1174

15 1518 1710 1428 1616 1517 1289 1148 1463

Mean 1697 1682 1580 1679 1568 1320 1356 1346

SD 179 165 174 235 210 191 220 177

No. Group

R S T U V W X Y

1 1314 1399 1629 1450 1339 1397 1602 1040

2 1210 1481 1348 1694 1594 1289 1504 1414

3 1152 1425 1409 1584 1117 1400 1225 1673

4 1362 1390 1458 1486 1530 1548 1688 1802

5 1241 1480 1387 1719 1350 1428 1597 1579

6 1221 1226 1361 1542 1455 1371 1702 1725

7 1341 1427 1274 1736 1506 1284 1531 1607

8 1534 1439 1336 1673 1552 1503 1638 1458

9 1477 1229 1371 1384 1219 1633 1871 1530

10 1370 1427 1338 1469 1485 1426 1528 1780

11 1176 1460 1199 1502 1139 1210 1623 1436

12 1252 1148 1333 1559 1409 1499 1844 1318

13 1455 1295 1762 1544 1557 1678 1354 1806

14 1229 1178 1490 1395 1454 1148 1867 1528

15 1610 1254 1450 1384 1475 1579 1694 1176

Mean 1330 1351 1410 1541 1412 1426 1618 1525

SD 138 116 139 120 150 152 179 226

4

2. Weibull distribution graphs. The slope is Weibull modulus (X-axis = ln(strength); Y-axis = lnln(1/(1-Pf)); Pf = failure probability)

Control group

5

(2) Airborne-particle abrasion with 25 μm alumina – Group B to I.

6

(3) Airborne-particle abrasion with 50 μm alumina – Group J to Q.

7

(3) Airborne-particle abrasion with 125 μm alumina – Group R to Y.

8

3. Raw data of surface roughness (Sa) estimated by confocal laser scanning microscopy

No. Group

A B C D E F G H I

1 0.067 0.345 0.339 0.343 0.387 0.481 0.546 0.597 0.650

2 0.068 0.304 0.373 0.336 0.364 0.474 0.530 0.607 0.633

3 0.071 0.332 0.313 0.315 0.408 0.512 0.556 0.549 0.624

Mean 0.069 0.339 0.342 0.331 0.386 0.489 0.544 0.584 0.636

SD 0.002 0.007 0.030 0.015 0.022 0.020 0.013 0.031 0.013

No. Group

J K L M N O P Q

1 0.407 0.494 0.495 0.600 0.534 0.546 0.604 0.637

2 0.470 0.485 0.523 0.616 0.542 0.579 0.608 0.710

3 0.445 0.499 0.494 0.636 0.566 0.604 0.623 0.671

Mean 0.441 0.493 0.504 0.617 0.547 0.576 0.612 0.673

SD 0.032 0.007 0.016 0.018 0.017 0.029 0.010 0.037

No. Group

R S T U V W X Y

1 0.454 0.462 0.564 0.562 0.738 0.904 0.870 0.966

2 0.436 0.45 0.576 0.602 0.729 0.897 0.798 0.891

3 0.429 0.425 0.567 0.576 0.755 0.874 0.865 0.859

Mean 0.440 0.446 0.569 0.580 0.741 0.892 0.844 0.905

SD 0.013 0.019 0.006 0.020 0.013 0.016 0.040 0.055

9

4. X-ray diffractometry graphs

(1) Control group

2θ (degree)

Inte

nsi

ty

10

(2) Airborne-particle abrasion with 25 μm alumina– Group B to I.

2θ (degree)

2θ (degree)

Inte

nsi

ty

Inte

nsi

ty

11

(3) Airborne-particle abrasion with 50 μm alumina – Group J to Q.

2θ (degree)

2θ (degree)

Inte

nsi

ty

Inte

nsi

ty

12

(4) Airborne-particle abrasion with 125 μm alumina – Group R to Y.

Inte

nsi

ty

Inte

nsi

ty

2θ (degree)

2θ (degree)

13

5. Raw data of shear bond strength before thermocycling with resin cement

No. Group

A B C D E F G H I

1 4.2 7.7 11.2 15.2 9.7 10.7 11.3 16.5 13.6

2 6.5 10.0 13.2 14.1 15.4 12.6 10.4 11.7 13.0

3 6.5 15.5 15.5 11.7 20.0 7.7 13.4 13.1 9.0

4 6.7 15.1 8.7 11.7 9.5 17.0 10.1 17.7 17.8

5 9.6 8.3 9.5 11.2 12.1 11.1 13.5 15.4 10.1

6 4.2 7.7 11.2 15.2 9.7 10.7 11.3 16.5 13.6

7 6.5 10.0 13.2 14.1 15.4 12.6 10.4 11.7 13.0

8 6.5 15.5 15.5 11.7 20.0 7.7 13.4 13.1 9.0

9 6.7 15.1 8.7 11.7 9.5 17.0 10.1 17.7 17.8

10 9.6 8.3 9.5 11.2 12.1 11.1 13.5 15.4 10.1

Mean 6.7 11.3 11.6 12.8 13.3 11.8 11.7 14.9 12.7

SD 1.92 3.73 2.77 1.76 4.42 3.40 1.62 2.46 3.44

No. Group

J K L M N O P Q

1 10.6 10.3 20.1 12.4 18.9 10.6 12.3 21.3

2 18.3 12.3 10.7 14.1 15.4 20.0 20.6 18.0

3 17.6 14.5 12.0 16.0 13.7 16.0 20.5 12.5

4 10.5 14.0 13.2 13.6 13.9 12.4 22.5 18.3

5 11.7 9.8 17.4 20.4 15.5 17.3 14.5 21.5

6 10.6 10.3 20.1 12.4 18.9 10.6 12.3 21.3

7 18.3 12.3 10.7 14.1 15.4 20.0 20.6 18.0

8 17.6 14.5 12.0 16.0 13.7 16.0 20.5 12.5

9 10.5 14.0 13.2 13.6 13.9 12.4 22.5 18.3

10 11.7 9.8 17.4 20.4 15.5 17.3 14.5 21.5

Mean 13.7 12.2 14.7 15.3 15.5 15.3 18.1 18.3

SD 3.88 2.12 3.94 3.13 2.08 3.78 4.41 3.64

14

No. Group

R S T U V W X Y

1 9.0 8.6 11.6 9.9 13.4 11.5 10.7 15.5

2 9.2 13.6 11.1 15.1 10.6 11.1 9.4 12.3

3 11.7 7.9 12.0 11.2 15.6 11.0 9.7 10.4

4 14.8 9.1 10.5 12.7 14.3 12.5 17.3 11.7

5 9.1 14.8 11.3 11.2 6.3 11.2 15.8 10.5

6 9.0 8.6 11.6 9.9 13.4 11.5 10.7 15.5

7 9.2 13.6 11.1 15.1 10.6 11.1 9.4 12.3

8 11.7 7.9 12.0 11.2 15.6 11.0 9.7 10.4

9 14.8 9.1 10.5 12.7 14.3 12.5 17.3 11.7

10 9.1 14.8 11.3 11.2 6.3 11.2 15.8 10.5

Mean 10.8 10.8 11.3 12.0 12.0 11.5 12.6 12.1

SD 2.52 3.16 0.56 1.99 3.70 0.61 3.70 2.07

15

6. Raw data of shear bond strength after thermocycling with resin cement

No. Group

A B C D E F G H I

1 3.6 4.8 5.8 12.0 9.4 8.2 11.1 7.3 9.6

2 4.3 2.4 10.6 12.9 11.0 11.5 6.1 7.0 12.7

3 3.3 10.0 10.8 4.1 8.6 6.3 12.0 9.2 7.6

4 2.2 10.9 8.2 7.7 7.2 6.1 5.3 14.0 8.8

5 1.5 6.2 6.2 5.6 5.6 11.1 9.3 9.7 5.6

6 3.6 4.8 5.8 12.0 9.4 8.2 11.1 7.3 9.6

7 4.3 2.4 10.6 12.9 11.0 11.5 6.1 7.0 12.7

8 3.3 10.0 10.8 4.1 8.6 6.3 12.0 9.2 7.6

9 2.2 10.9 8.2 7.7 7.2 6.1 5.3 14.0 8.8

10 1.5 6.2 6.2 5.6 5.6 11.1 9.3 9.7 5.6

Mean 3.0 6.9 8.3 8.5 8.4 8.6 8.8 9.4 8.9

SD 1.12 3.56 2.36 3.87 2.07 2.57 2.97 2.80 2.62

No. Group

J K L M N O P Q

1 10.8 6.8 13.1 7.4 13.1 8.3 8.3 16.7

2 14.7 13.2 8.5 13.9 11.7 13.0 15.6 12.6

3 14.3 13.0 9.3 11.7 11.9 12.6 15.9 9.3

4 8.5 11.8 12.0 9.9 7.3 8.9 14.5 15.5

5 12.4 11.9 8.8 14.1 8.1 12.6 8.9 9.5

6 10.8 6.8 13.1 7.4 13.1 8.3 8.3 16.7

7 14.7 13.2 8.5 13.9 11.7 13.0 15.6 12.6

8 14.3 13.0 9.3 11.7 11.9 12.6 15.9 9.3

9 8.5 11.8 12.0 9.9 7.3 8.9 14.5 15.5

10 12.4 11.9 8.8 14.1 8.1 12.6 8.9 9.5

Mean 12.1 11.3 10.3 11.4 10.4 11.1 12.6 12.7

SD 2.57 2.61 2.07 2.82 2.56 2.28 3.73 3.38

16

No. Group

R S T U V W X Y

1 3.8 8.4 8.4 7.7 11.1 13.1 11.8 12.5

2 6.1 5.2 7.3 14.8 4.5 7.8 7.7 7.1

3 10.9 5.2 11.6 9.6 11.5 10.1 7.5 9.0

4 5.3 6.6 16.2 8.1 9.7 13.7 9.5 12.5

5 4.3 5.6 9.5 15.4 10.1 7.5 12.8 8.1

6 3.8 8.4 8.4 7.7 11.1 13.1 11.8 12.5

7 6.1 5.2 7.3 14.8 4.5 7.8 7.7 7.1

8 10.9 5.2 11.6 9.6 11.5 10.1 7.5 9.0

9 5.3 6.6 16.2 8.1 9.7 13.7 9.5 12.5

10 4.3 5.6 9.5 15.4 10.1 7.5 12.8 8.1

Mean 8.4 8.6 9.8 10.3 9.5 10.1 10.7 10.5

SD 3.95 2.97 3.16 3.07 2.57 2.72 3.16 3.15

17

7. Statistical Results 4-way ANOVA and multiple comparison Sheffé test (α = .05) 1) Fracture strengths of monolithic zirconia specimens

Between-Subjects Factors

Value Label N

Size

1 25 120

2 50 120

3 125 120

4 Control 15

Pressure

1 2 bar 180

2 4 bar 180

3 Control 15

Time

1 10 s 180

2 20 s 180

3 Control 15

Angle

1 45° 180

2 90° 180

3 Control 15

18

Tests of Between-Subjects Effects Dependent Variable: strength

Source Type III Sum of

Squares df

Mean

Square F Sig.

Corrected Model 47331413.957a 24 1972142.248 59.639 .000

Intercept 587025775.613 1 587025775.613 17752.175 .000

Size 8702236.717 2 4351118.358 131.582 .000

Pressure 4848104.803 1 4848104.803 146.611 .000

Time 3724864.336 1 3724864.336 112.643 .000

Angle 11211.336 1 11211.336 .339 .561

Size × Pressure 20677986.906 2 10338993.453 312.660 .000

Size × Time 5909509.006 2 2954754.503 89.354 .000

Size × Angle 108795.139 2 54397.569 1.645 .194

Pressure × Time 353001.469 1 353001.469 10.675 .001

Pressure × Angle 126075.469 1 126075.469 3.813 .052

Time × Angle 3900.625 1 3900.625 .118 .731



Size × Time × Angle 457854.717 2 228927.358 6.923 .001


Size × Pressure × Time × Angle 588903.817 2 294451.908 8.904 .000

Error 11573738.000 350 33067.823

Total 1012104439.000 375

Corrected Total 58905151.957 374

a. R Squared = .804 (Adjusted R Squared = .790)

Estimated Marginal Means

Grand Mean

Dependent Variable: strength

Mean Std. Error 95% Confidence Interval

Lower Bound Upper Bound

1594.323a 9.390 1575.854 1612.792

a. Based on modified population marginal mean.

19

Post Hoc Tests

① Size

Multiple Comparisons Dependent Variable: strength

Scheffé

(I) Size (J) Size Mean

Difference (I-J) Std. Error Sig.

95% Confidence Interval


25

50 293.7333* 23.47617 .000 227.7855 359.6811 125 356.7917* 23.47617 .000 290.8439 422.7395 Control 363.1500* 49.80047 .000 223.2536 503.0464

50

25 -293.7333* 23.47617 .000 -359.6811 -227.7855 125 63.0583* 23.47617 .067 -2.8895 129.0061 Control 69.4167* 49.80047 .585 -70.4797 209.3131

125

25 -356.7917* 23.47617 .000 -422.7395 -290.8439 50 -63.0583* 23.47617 .067 -129.0061 2.8895 Control 6.3583* 49.80047 .999 -133.5381 146.2547

Control

25 -363.1500* 49.80047 .000 -503.0464 -223.2536 50 -69.4167* 49.80047 .585 -209.3131 70.4797 125 -6.3583* 49.80047 .999 -146.2547 133.5381

Based on observed means.

The error term is Mean Square (Error) = 33067.823.

*. The mean difference is significant at the .05 level.

Homogeneous Subsets

strength

Scheffé

Size N Subset

1 2

Control 15 1453.8667 125 120 1460.2250 50 120 1523.2833 25 120 1817.0167 Sig. .366 1.000

Means for groups in homogeneous subsets are isplayed. Based on observed means.


a. Uses Harmonic Mean Sample Size = 43.636.

b. The group sizes are unequal. The harmonic mean of the group sizes is used.

Type I error levels are not guaranted. c. Alpha = .05.

20

② Pressure


Scheffé

(I)

Pressure

(J)

Pressure

Mean Difference

(I-J) Std. Error Sig.

95% Confidence

Interval

Lower

Bound

Upper

Bound

2 bar 4 bar -232.0944* 19.16821 .000 -279.2149 -184.9740 Control 30.2611* 48.86954 .826 -89.8729 150.3951

4 bar 2 bar 232.0944* 19.16821 .000 184.9740 279.2149 Control 262.3556* 48.86954 .000 142.2215 382.4896

Control 2 bar -30.2611* 48.86954 .826 -150.3951 89.8729 4 bar -262.3556* 48.86954 .000 -382.4896 -142.2215

Based on observed means. The error term is Mean Square (Error) = 430.679.


Homogeneous Subsets

strength

Scheffé

Pressure N Subset

1 2

Control 15 1453.8667

2 bar 180 1484.1278

4 bar 180 1716.2222

Sig. .766 1.000

Means for groups in homogeneous subsets are displayed. Based on observed

means. The error term is Mean Square (Error) = 33067.823.



Type I error levels are not guaranteed.

c. Alpha = .05.

21

③ Time


Scheffé

(I) Time (J) Time Mean

Difference (I-J)

Std. Error Sig.

95% Confidence

Interval

Lower

Bound

Upper

Bound

10 s 20 s -203.4389* 19.16821 .000 -250.5593 -156.3185 Control 44.5889* 48.86954 .660 -75.5451 164.7229

20 s 10 s 203.4389* 19.16821 .000 156.3185 250.5593 Control 248.0278* 48.86954 .000 127.8938 368.1618

Control 10 s -44.5889* 48.86954 .660 -164.7229 75.5451 20 s -248.0278* 48.86954 .000 -368.1618 -127.8938




Homogeneous Subsets

strength

Scheffé

Time N Subset

1 2

Control 15 1453.8667

10 s 180 1498.4556

20 s 180 1701.8944

Sig. .561 1.000






c. Alpha = .05.

22

④ Incidence angle


Scheffé

(I)

Angle

(J)

Angle

Mean Difference

(I-J) Std. Error Sig.


Lower

Bound

Upper

Bound

45° 90° -11.1611* 19.16821 .844 -58.2815 35.9593Control 140.7278* 48.86954 .017 20.5938 260.8618

90° 45° 11.1611* 19.16821 .844 -35.9593 58.2815Control 151.8889* 48.86954 .009 31.7549 272.0229

Control 45° -140.7278* 48.86954 .017 -260.8618 -20.593890° -151.8889* 48.86954 .009 -272.0229 -31.7549




Homogeneous Subsets

strength

Scheffé

Angle N Subset

1 2

Control 15 1453.8667

45° 180 1594.5944

90° 180 1605.7566

Sig. 1.000 .964





Type I error levels are not guaranteed. c. Alpha = .05.

23

2) Shear bond strengths before thermocycling


Value Label N

Size

1 25 80

2 50 80

3 125 80

4 Control 10

Pressure

1 2 bar 120

2 4 bar 120

3 Control 10

Time

1 10 s 120

2 20 s 120

3 Control 10

Angle

1 45° 120

2 90° 120

3 Control 10

24

Tests of Between-Subjects Effects Dependent Variable: Strength

Source Type III Sum

of Squares df

Mean

Square F Sig.


Intercept 22610.990 1 22610.990 2779.529 .000

Size 613.721 2 306.861 37.722 .000

Pressure 114.817 1 114.817 14.114 .000

Time 164.011 1 164.011 20.162 .000

Angle 2.904 1 2.904 .357 .551

Size × Pressure 61.961 2 30.981 3.808 .024

Size × Time 29.545 2 14.773 1.816 .165

Size × Angle .732 2 .366 .045 .956

Pressure × Time 1.411 1 1.411 .173 .677

Pressure × Angle 6.667 1 6.667 .820 .366

Time × Angle 1.014 1 1.014 .125 .724

Size × Pressure × Time 3.121 2 1.561 .192 .826

Size × Pressure × Angle 10.885 2 5.443 .669 .513

Size × Time × Angle 12.652 2 6.326 .778 .461


Size × Pressure × Time × Angle 1.984 2 .992 .122 .885

Error 1830.336 225 8.135

Total 44994.220 250




Grand Mean

Dependent Variable: Strength



12.919a .180 12.564 13.275


25

Post Hoc Tests

① Size

Multiple Comparisons Dependent Variable: Strength

Scheffé

(I) Size (J) Size

Mean

Difference

(I-J)

Std. Error Sig.



25

50 -2.8550* .45097 .000 -4.1253 -1.5847

125 .8950 .45097 .271 -.3753 2.1653

Control 5.8250* .95664 .000 3.1304 8.5196

50

25 2.8550* .45097 .000 1.5847 4.1253

125 3.7500* .45097 .000 2.4797 5.0203

Control 8.6800* .95664 .000 5.9854 11.3746

125

25 -.8950 .45097 .271 -2.1653 .3753

50 -3.7500* .45097 .000 -5.0203 -2.4797

Control 4.9300* .95664 .000 2.2354 7.6246

Control

25 -5.8250* .95664 .000 -8.5196 -3.1304

50 -8.6800* .95664 .000 -11.3746 -5.9854

125 -4.9300* .95664 .000 -7.6246 -2.2354




Homogeneous Subsets

Strength

Scheffé

Size N Subset

1 2 3

Control 10 6.7000

125 80 11.6300

25 80 12.5250

50 80 15.3800

Sig. 1.000 .698 1.000






c. Alpha = .05.

26

② Pressure

Multiple Comparisons


Scheffé

(I)

Pressure

(J)

Pressure

Mean

Difference

(I-J)

Std. Error Sig.


Lower

Bound

Upper

Bound

2 bar 4 bar -1.3833* .36821 .001 -2.2907 -.4760

Control 5.7867* .93876 .000 3.4734 8.0999

4 bar 2 bar 1.3833* .36821 .001 .4760 2.2907

Control 7.1700* .93876 .000 4.8568 9.4832

Control 2 bar -5.7867* .93876 .000 -8.0999 -3.4734

4 bar -7.1700* .93876 .000 -9.4832 -4.8568




Homogeneous Subsets

Strength

Scheffé

Pressure N Subset

1 2

Control 10 6.7000

2 bar 120 12.4867

4 bar 120 13.8700

Sig. 1.000 .223






c. Alpha = .05.

27

③ Time



Scheffé

(I)

Time

(J)

Time

Mean

Difference

(I-J)

Std. Error Sig.



10 s 20 s -1.6533* .36821 .000 -2.5607 -.7460

Control 5.6517* .93876 .000 3.3384 7.9649

20 s 10 s 1.6533* .36821 .000 .7460 2.5607

Control 7.3050* .93876 .000 4.9918 9.6182

Control 10 s -5.6517* .93876 .000 -7.9649 -3.3384

20 s -7.3050* .93876 .000 -9.6182 -4.9918




Homogeneous Subsets

Strength

Scheffé

Time N Subset

1 2

Control 10 6.7000

10 s 120 12.3517

20 s 120 14.0050

Sig. 1.000 .118






c. Alpha = .05.

28

④ Incidence angle



Scheffé

(I)

Angle

(J)

Angle

Mean

Difference

(I-J)

Std. Error Sig.


Lower

Bound

Upper

Bound

45° 90° .2200 .36821 .837 -.6873 1.1273

Control 6.5883* .93876 .000 4.2751 8.9016

90° 45° -.2200 .36821 .837 -1.1273 .6873

Control 6.3683* .93876 .000 4.0551 8.6816

Control 45° -6.5883* .93876 .000 -8.9016 -4.2751

90° -6.3683* .93876 .000 -8.6816 -4.0551




Homogeneous Subsets

Strength

Scheffé

Angle N Subset

1 2

Control 10 6.7000

90° 120 13.0683

45° 120 13.2883

Sig. 1.000 .962






c. Alpha = .05.

29

3) Shear bond strengths after thermocycling


Value Label N

Size

1 25 80

2 50 80

3 125 80

4 Control 10

Pressure

1 2 bar 120

2 4 bar 120

3 Control 10

Time

1 10 s 120

2 20 s 120

3 Control 10

Angle

1 45° 120

2 90° 120

3 Control 10

30

Tests of Between-Subjects Effects Dependent Variable: Strength

Source Type III Sum

of Squares df

Mean

Square F Sig.


Intercept 11288.656 1 11288.656 1619.757 .000

Size 405.304 2 202.652 29.078 .000

Pressure 49.142 1 49.142 7.051 .008

Time 81.434 1 81.434 11.685 .001

Angle 5.340 1 5.340 .766 .382

Size × Pressure 9.421 2 4.711 .676 .510

Size × Time 40.827 2 20.414 2.929 .055

Size × Angle .450 2 .225 .032 .968

Pressure × Time 9.204 1 9.204 1.321 .252

Pressure × Angle .368 1 .368 .053 .818

Time × Angle 1.148 1 1.148 .165 .685


Size × Pressure × Angle 4.260 2 2.130 .306 .737

Size × Time × Angle 7.862 2 3.931 .564 .570

Pressure × Time × Angle 3.901 1 3.901 .560 .455

Size × Pressure × Time × Angle 7.203 2 3.601 .517 .597

Error 1568.104 225 6.969

Total 25106.400 250




Grand Mean




9.451a .167 9.122 9.780


31

Post Hoc Tests

① Size


Scheffé

(I) Size (J) Size Mean

Difference (I-J)

Std.

Error Sig.



25

50 -3.0475* .41741 .000 -4.2233 -1.8717

125 -.7275 .41741 .388 -1.9033 .4483

Control 5.4825* .88547 .000 2.9883 7.9767

50

25 3.0475* .41741 .000 1.8717 4.2233

125 2.3200* .41741 .000 1.1442 3.4958

Control 8.5300* .88547 .000 6.0358 11.0242

125

25 .7275 .41741 .388 -.4483 1.9033

50 -2.3200* .41741 .000 -3.4958 -1.1442

Control 6.2100* .88547 .000 3.7158 8.7042

Control

25 -5.4825* .88547 .000 -7.9767 -2.9883

50 -8.5300* .88547 .000 -11.0242 -6.0358

125 -6.2100* .88547 .000 -8.7042 -3.7158




Homogeneous Subsets

Strength

Scheffé

Size N Subset

1 2 3

Control 10 2.9800

25 80 8.4625

125 80 9.1900

50 80 11.5100

Sig. 1.000 .776 1.000






c. Alpha = .05.

32

② Pressure


Scheffé

(I)

Pressure

(J)

Pressure

Mean

Difference

(I-J)

Std. Error Sig.


Lower

Bound

Upper

Bound

2 bar 4 bar -.9050* .34082 .031 -1.7448 -.0652

Control 6.2883* .86891 .000 4.1472 8.4295

4 bar 2 bar .9050* .34082 .031 .0652 1.7448

Control 7.1933* .86891 .000 5.0522 9.3345

Control 2 bar -6.2883* .86891 .000 -8.4295 -4.1472

4 bar -7.1933* .86891 .000 -9.3345 -5.0522




Homogeneous Subsets

Strength

Scheffé

Pressure N Subset

1 2

Control 10 2.9800

2 bar 120 9.2683

4 bar 120 10.1733

Sig. 1.000 .471






c. Alpha = .05.

33

③ Time


Scheffé

(I) Time (J) Time

Mean

Difference

(I-J)

Std. Error Sig.



10 s 20 s -1.1650* .34082 .003 -2.0048 -.3252

Control 6.1583* .86891 .000 4.0172 8.2995

20 s 10 s 1.1650* .34082 .003 .3252 2.0048

Control 7.3233* .86891 .000 5.1822 9.4645

Control 10 s -6.1583* .86891 .000 -8.2995 -4.0172

20 s -7.3233* .86891 .000 -9.4645 -5.1822




Homogeneous Subsets

Strength

Scheffé

Time N Subset

1 2

Control 10 2.9800

10 s 120 9.1383

20 s 120 10.3033

Sig. 1.000 .288





Type I error levels are not guaranteed

c. Alpha = .05.

34

④ Incidence angle


Scheffé

(I)

Angle

(J)

Angle

Mean

Difference (I-J)

Std.

Error Sig.



45° 90° -.2983 .34082 .682 -1.1382 .5415

Control 6.5917* .86891 .000 4.4505 8.7328

90° 45° .2983 .34082 .682 -.5415 1.1382

Control 6.8900* .86891 .000 4.7489 9.0311

Control 45° -6.5917* .86891 .000 -8.7328 -4.4505

90° -6.8900* .86891 .000 -9.0311 -4.7489




Homogeneous Subsets

Strength

Scheffé

Angle N Subset

1 2

Control 10 2.9800

45° 120 9.5717

90° 120 9.8700

Sig. 1.000 .921






c. Alpha = .05.

문 록

다양한 샌드블라스 건 단 지 코니아

물 레진 시 트 착강도에 미치는

과에 한 연

울 학 학원 치 과학과 치과보철학 공

(지도 수 훈)

문 지

연 : 지 코니아 보철물 간 안 레진시 트 착

하여 시행하는 샌드블라스 지 코니아 상 변 야 하고

아가 물 에 향 주 문에 샌드블라스 건 달리하여

단 지 코니아 물 레진시 트 착력 측 하여

건 가진 샌드블라스 프로 콜 시하고 한다.

재료 : 샌드블라스 건 – 알루미 (25, 50, 125㎛),

사 압력(2bar, 4bar), 사 각도(45°, 90°), 사 시간(10 , 20 )

달리하고 포함하여 25개 그룹 단 지 코니아

시편 비하 다. 시편 강도실험 하여 bar 태(45 × 3 ×

4mm) 시편 그룹당 15개씩 하여 에 한 건 로

샌드블라스 시행한 3 강도 시행하고 블 계수

특 강도 계산하 다. 또한 X 통한 단사 상 변 측 ,

공 주사 레 미경 한 거칠 측 , 원 력 미경

통한 찰, 라만 한 에 상 변 ,

주사 미경 통한 찰하 다. 동시에 원 태(Ø 9 ×

1mm) 시편 그룹당 20개씩 비하여 레진시 트 ( 비아 F2.0)

착 후에 각 그룹당 10개씩 2개 하 그룹 로 다시 한 후

한쪽만 5000 열순 시행하여 열순 과 후 레진시 트

결합강도 차 측 하여 비 하 다.

통계는 4개 변수 상 고려한 사원 산 통하여

하고 검 그룹 리 Sheffé 사후검

시행하여 동 집단 하 다 (α = .05)

결 과 : 블 포에 특 강도는 25㎛에 가 게 타났

같 내에 는 변태강 상과 미 재료 강도에 동시에

향 쳤다. 25㎛에 는 변태강 향 로 강도가 게

가하 50과 125㎛ 강도는 과 통계

견 지 않았다. 거칠 는 가 클수록, 압력 수록, 시간

수록, 각도가 클수록 가하 다. 단사 가 클수록, 압력

수록, 각도가 클수록 많 생하 지만 시간 차 는 크지 않았다.

라만 에 알루미늄 사 드 가 마찰시킨 에

단사 포비 에 가 울수록 많 재하 10㎛

후에 는 사라짐 보 다. 원 력 미경 통한 재료

찰 보 에 비해 실험 에 게는 10 , 많게는 18

상 로 들 찰할 수 었 주사 미경 통해

가 클수록, 압력 크고 시간 수록 거칠고 큰 틈과 철 가진

지 코니아 볼 수 었다. 레진 시 트 결합력 열순

후 50㎛에 가 게 타났 같 내에 시간

수록, 압력 수록 게 결합력 찰 었다.

크 , 압력, 시간, 각도 4개 각도 한 지 3개

가 강도 레진시 트 단강도 값에 는 향

미치는 것 로 타났다.

결 론 : 알루미 한 샌드블라스 단 지 코니아

결 변 시키고 결함 포 꾸어 강도

물 에 향 미쳤 레진시 트 결합강도 게

가시켰다. 실험에 하여 천 는 샌드블라스 건 각도

상 없 50㎛, 4 bar, 20 다.

주 어: 단 지 코니아, 강도, 상 변 , 결합강도, 레진시 트

학 : 2010-31187

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