assessment of bone density-ortho / orthodontic courses by indian dental academy

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INDIAN DENTAL ACADEMY

Leader in continuing dental educationwww.indiandentalacademy.com


Dr. K. Praveen KumarPG

Narayana Dental college & Hospital

AJODO - JANUARY 2008;133:30-7

DENSITY OF THE ALVEOLAR AND BASAL BONES OF THE MAXILLA

AND THE MANDIBLEby

Hyo-Sang Park, Youn-Ju Lee, Seong-Hwa Jeong


PURPOSE

To investigate and evaluate the density of the alveolar and basal bones of the maxilla and the mandible.


WHY - DENSITYIT DETERMINES

TREATMENT PLANNINGIMPLANT DESIGNSURGICAL APPROACHHEALING TIMEINITIAL PROGRESSIVE BONE LOADINGSUCCESS RATE


INTRODUCTION

CLASSIFICATION

LEONARD LINKOW (1970)

CLASS – I : Ideal bone type with evenly spaced

trabeculae and small cancellated spaces.

CLASS – II : Slightly larger cancellated spaces with less

uniformity of the osseous pattern.

CLASS – III : Large marrow filled spaces exist between

bone trabeculae.


LEKHOLM AND ZARB (1985)

QUALITY – I : Homogenous compact boneQUALITY – II : Thick layer of compact bone

surrounding a core of dense trabecular

bone.QUALITY – III : Thin layer of cortical bone

surrounding dense trabecular bone of

favorable strength.QUALITY – IV : Thin layer of cortical bone

surrounding a core of low density trabecular

bone.


MISCH’S CLASSIFICATION(1988)

D1 bone – >1250 HU. ( DENSE CORTICAL)

D2 bone – 850 – 1250 HU ( POROUS CORTICAL)

D3 bone – 350 – 850 HU ( COARSE TRABECULAR)

D4 bone – 150 – 350 HU ( FINE TRABECULAR)

D5 bone – <150 HU ( SOFT)


ADVANTAGESTo overcome problems associated with anchorage

loss.

Easy placement and easy removal.

Immediate loading

Minimal anatomical limitations of their small size.

Low cost compared with other skeletal anchorage options.

No patient compliance.


DISADVANTAGESDisplacement on loading.

Threatens adjacent dental roots or vital organs.


INDICATIONSEn-masse retraction of the Anterior and posterior

teeth.

Retraction of the whole dentition.

Molar distalization.

Molar uprighting.

Protraction of molars.

Forced eruption of the canines.

Lingual orthodontic treatment.


CONTRAINDICATIONSAbsolute contraindication: Severe systemic disorder, eg: osteoporosis. Psychiatric diseases, eg: psychoses

dysmorphobia. Alcoholics drug abusers.

Relative contraindications: Insufficient volume of bone Poor bone quality Patients undergoing radiation therapy Insulin dependent diabetes Heavy smokers


IMPLANT TYPES – ORTHODONTICS

MINI SCREWS

MINI PLATES

MICRO SCREWS

DENTAL IMPLANTS


MOST RECOMMENDED SITESMid palatine area.The alveolar bone between the maxillary 2nd

premolar & molar.The Mandibular 1st and 2nd molars.


OTHER POSSIBLE SITESRetromolar area.The chinThe inferior ridge of the piriform

aperture(ANS).The inferior ridge of the Zygomatic archThe maxillary tuberosityThe mandibular body


FACTORS AFFECTING SUCCESS

HOST – BONE DENSITY

IMPLANT – SIZE, SHAPE, SURFACE, COMPOSITION

SURGICAL METHOD – OPEN – CLOSED METHOD


METHODSMANUAL BONE MAPPING

RADIOGRAPHIC IOPA ORTHOPANOGRAM LATERAL CEPHALOGRAM

IMAGING COMPUTER TOMOGRAM SCANNING ( CT- SCAN

)


MATERIALS AND METHODSSAMPLE SIZE - 63 23 Men (Ages, 29 ± 10.9) 40 Women (Ages, 25.6 ± 7.6)

63 sets of CT images were collected

V-WORKS IMAGING software (Cybermed, Seoul, Korea)


STATISTICAL ANALYSISSAS software (version 8.01; SAS, Cary, NC).

Combined sample was used for the statistical analysis as there was no no difference between Men and Women.

1 way analysis of variance (ANOVA) is performed to analyze differences of bone density at the incisor, canine, premolar, molar, retromolar and tuberosity areas in the maxilla and the mandible.

Tukey multiple range test was used for multiple comparisons.

The Student ‘t’ test is used to evaluate differences between the alveolar and the basal bones, and the difference between the maxilla and the mandible.


Error possibilitiesTo calculate the errors of measurement, 69

randomly selected measurement sites were measured 1 month later.

The measurement error was calculated based on the differences between the first and second measured values with the paired ‘t’ test.

There was no significant difference between the two measurements according to Dahlberg’s formula.


RESULTSMAXILLA – BASAL AND ALVEOLAR ( CANCELLOUS BONE ) The overall bone density between 280 – 500 HU Except for the lowest in the tuberosity area 151 HU

MAXILLARY ALVEOLAR BONE ( CORTICAL BONE )The overall bone density between 810 – 940 HU EXCEPT for maxillary tuberosity – 443 HU (Buccal

cortical). - 615 HU (Palatal

cortical).MAXILLARY BASAL BONE ( CORTICAL BONE )The overall bone density between 835 – 1113 HU EXCEPT for maxillary tuberosity – 542 HU


MANDIBULAR ALVEOLAR BONE ( CANCELLOUS BONE ) The overall bone density between 300 – 500 HU MANDIBULAR BASAL BONE ( CANCELLOUS BONE ) The overall bone density between 170 – 440 HU

MANDIBULAR ALVEOLAR BONE ( CORTICAL BONE ) The overall bone density between 810 – 1580 HU MANDIBULAR BASAL BONE ( CORTICAL BONE ) The overall bone density between 1320 – 1560 HU THE RANGE INCREASED GRADUALLY FROM INCISOR

TO RETROMOLAR AREA.


DISCUSSIONJaffin and Berman reportd, implant failure rate was 3% for type – 1, 2, 3 bone densities 35% for type – 4 bone density( According to Lekholm and Zarb bone quality

description )

Truhlar etal concluded that failure rate was Q1>Q2>Q3

Placement of implants in D1 bone was less successful than D2 and D3 bones.


Comparisons of densities between alveolar and basal bones of the mandible ( *P < 0.05 ).


Comparisons of density between maxillary and mandibular alveolar bones (*P <0.05 )


Comparisons of bone density of the paramedian area at the canine and molar of the buccal alveolar and basal bones


Cancellous bone did not show much difference between the maxilla and the mandible.

Cortical bone in the maxilla is much thinner and less dense than in the mandible.


CONCLUSIONBasal bone generally showed higher density

than that of alveolar bone.

Cortical bone of the mandible was denser than that of the maxilla, where as cancellous bone had similar densities between the mandible and the maxilla with some exception.

These data could provide valuable information when selecting sites and choosing placement methods for mini screw and micro screw implants.


REVIEW OF LITERATUREThe normal human/primate craniofacial skeleton,

including the mandible, is known to grow in a symmetric

manner bilaterally with complex interactions between

specific growth sites and local remodeling.(AJO-D,1988 Feb).


REFERENCE

Skeletal anchorage system for open bite correction – Umemori M, Sugawara J, Mitani H, AJODO 1999 ; 115: 166-74.

The possibility of skeletal anchorage – Creekmore TD, JCO 1983; 17: 266-69.

Micro-implant anchorage for treatment of skeletal class I bialveolar protrusion – Park HS, Bae Sm, Kyung HM, JCO 2001; 35: 417-22.

The efficient use of midpalatal mini screw implants – Lee JS, Kim DH, Park YC, Kyung SH, AO 2004;74:711-14.

A density comparison of human alveolar and retromolar bone – Buck DL, Wheeler PW, AO 1969; 39: 133-36.


Craniomandibular morphology with computed tomography - Miller, Cann, Nielsen, and Roda (AJO-DO), Volume 1988 Feb (117 - 125).

Factors affecting the clinical success of screw implants used as orthodontic anchorage – Park HS, Jeong SH, AJODO 2006;130:18-25.

The effect of altered bone metabolism on orthodontic tooth movement - Midgett RJ, Shaye R, Fruge JF AJO 1981; 80: 256-62.

Temperatures measured in human cortical bone when drilling – Matthews LS, Hirsch C, J Bone Joint Surg Am 1972;54:297-308.


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assessment of bone density-ortho / orthodontic courses by indian dental academy

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