a critical evaluation of different methods of recording

International Journal of Advancements in Research & Technology, Volume 2, Issue 12, December-2013ISSN 2278-7763

Copyright 2013 SciResPub. IJOART

A Critical Evaluation of different methods of recording centric jaw relation of completelyedentulous individuals - An In Vivo Study *

Dr C Sabarigirinathan1, Dr K Vinayagavel 2, Dr C Gunasekar 3, Dr Vikas 4, Dr Rupkumar 5, Dr Jeyanthi Kumari 6

1,2,5,6 (Dept of Prosthodontics, TamilNadu Government Dental College, Chennai, India ); 3 (Senior Staff Surgeon ( Dental ) ESICPGIMSR, KK Na-gar, Chennai, India ); 4 ( Private practitioner, Delhi, India)Email: [email protected], [email protected], [email protected]

ABSTRACT Accurate recording of maxillomandibular relations plays a pivotal role in the success of the complete denturerehabilitation. The centric relation is a repeatable and recordable relation which remains constant throughout life. There arevarious techniques used to record centric jaw relation namely 1.Intra oral graphic tracing 2.Extra oral gothic arch tracing 3.Nickand Notch method 4.Mush bite technique. This study was attempted to evaluate the efficacy, consistency and relative accuracyof the various methods used to record centric jaw relations.

Keywords : Articulator,Centric relation, Face bow transfer, Split cast technique

1 INTRODUCTION

The accurate recording and transfer of jaw rela-tion records[1] from the edentulous patient to the articulatoris essential for the restoration of function, speech, facialappearance, and maintenance of the comfort to patientsstomatognathic system. The patients maxillomandibularrelationships are dynamic and changes have been observedas age advances. Yoshiyuki Watanabe[2] has mentionedthat occlusal stability is an important aspect for success ofprosthetic treatment, and can only be achieved with an ac-curate determination of the mandibular position.

There are only approximate guides available to de-termine where to place the teeth; two of the most importantof these are vertical and horizontal relationship[3] of themandible to the maxillae, when constructing a completedenture. In dentulous patients proprioceptive impulsesfrom periodontal ligament guide the mandibular move-ments. Edentulous patients do not have any propriocep-tive guidance from their teeth to guide the mandibularmovements. The sources of proprioceptive impulses for anedentulous patient are transferred to the temporomandibu-lar joint.

For the rehabilitation of an edentulous patient,a learnable, repeatable and recordable maxilla to mandiblerelation is required, which remains constant throughoutthe life. There is substantial evidence indicating that, whendental influences are eliminated, a healthy elevating mus-culature will position the condyle in its most anterior andsuperior bracing position against the eminence. This seated

condylar position has been referred to as centric relation.

Centric and eccentric relations of mandible canbe recorded through check bites, graphic recordings, func-tional recordings and cephalometrics. These records arethen transferred to a semiadjustable articulator so that itcan be set to simulate the various jaw movements[4]. Thisstudy is an attempt to compare the relative accuracy of thethree different methods of recording centric relation usingintraoral tracing method as a standard. The comparison ofthe four registered records of centric relation will be doneusing SpiltCast mounting [5] on semiadjustable articulatorand by using another modified Ashs free plane articulator.

The methods used for recording centric relationmay be classified broadly as static or functional, and eachof these may be extraoral and intraoral techniques. Thestatic methods [3] are those that involve first placing themandible in centric relation with the maxillae and thenmaking a record of the relationship of the two occlusionrims to each other. The functional methods [3] are those thatinvolve functional activity or movement of the mandible atthe time the record is made. Accurate records of centricrelation have been made by all the methods in both classes.

The aims and objectives of the study were(1) To compare the efficiency of high tracer[6] , conven-

tional intraoral tracer [6] , mush bite technique[5]and Nick and Notch [5] method

5in determining

centric relation.(2) To evaluate the consistency of centric relation rec-

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ords obtained with four different techniques(3) To compare the deviation of centric relation rec-

ords in horizontal plane obtained with three dif-ferent techniques to those obtained with intraoraltracing technique, and

(4) To evaluate the deviation of centric relation recordsobtained with four different techniques using SplitCast technique

2 Materials and methods :

Ten edentulous patients who exhibited goodhealth, average neuromuscular coordination, and relativelygood ridges were selected at random from Department ofProsthodontics, Tamil Nadu Govt. Dental College & Hospi-tal, Chennai, India. Equal numbers of male and female pa-tients were selected between age group of 50 to 60 years. Atotal number of 10 edentulous individuals with class I skel-etal relationship were subjected to this study. The patientswere informed about the study and their written informedconsent was obtained before the commencement of thisprocedure.

Grouping of Samples: The readings taken in this studywere broadly grouped in two main groups :Group 1: Readings evaluated with the help of Spilt Castmounting.Group 2: Readings evaluated with the help of ModifiedAsh Free plane Articulator.Each group was further subdivided into 4 subgroups,namely(1) Intraoral tracing records evaluated with split castmounting designated as 1A(2) Extraoral tracing records evaluated with split castmounting designated as 1B(3) Nick and Notch occlusal records evaluated with splitcast mounting designated as 1C(4) Mush Bite technique records evaluated with split castmounting designated as 1D(5) Intraoral records evaluated with modified Ashs freeplane articulator designated as 2A(6) Extraoral records evaluated with modified Ashs freeplane articulator designated as 2B(7) Nick and Notch records evaluated with modified Ashsfree plane articulator designated as 2C(8) Mush Bite technique records evaluated with modifiedAshs free plane articulator designated as 2D

MethodologyDiagnosis and Impression Making: Edentulous individu-

als of age ranging from 51 to 60 years were taken in thisstudy.Primary impression was made with Type II impres-sion compound and primary casts were made. Customtrays on these primary impressions were fabricated withchemically activated denture base resin (DPI, India) with1.5mm wax spacer. Trays were trimmed and checked forextension in the patients mouth. Then border molding wasdone with low fusing tracing compound and secondaryimpression was made with Zinc Oxide Eugenol impressionpaste, the impression was poured with Type III dentalstone to obtain the master casts. This master cast was thenduplicated with reversible hydrocolloid to get two pairs ofupper and lower casts. Four pair of record bases havingsame thickness and extension was made with heat activat-ed acrylic resin.

FaceBow record was made with Dentatus face-bow and transferred to the Dentatus semiadjustable articu-lator . The upper cast was mounted on the upper memberof the articulator by using Split Cast Technique. Intraoraltracing, extraoral tracing, nick and notch method and mushbite technique were repeated 5 times and the most repeatedrecord was accepted.

Evaluation of the centric jaw relation recorded with fourdifferent registration methods:

1. Evaluation of extraoral tracing records in split casttechnique: The occlusal rims with extraoral recordings are seat-ed on the mounted upper and lower casts in semiadjustablearticulator. Record bases are checked for complete seatingon the mounted casts. Three reference points are made onthe upper split cast, one anterior to the incisive papilla andtwo posterolaterally, each made 10 mm anterior to the pos-terior border of the maxillary tuberosity. After seating, thearticulator was closed in centric position according to theinterocclusal records obtained. The discrepancy betweenthe cast and the split is measured with the help of a digitalVernier calliper. The readings are noted at all the three ref-erence points; one anterior and two posterolateral whichare already marked.

2.Evaluation of Nick and Notch method in split cast tech-nique : The centric relation records taken with Nick andNotch technique are properly seated on the mounted castson semiadjustable articulator. After seating, the articulatoris closed in centric position according to occlusal obtainedand the discrepancy between the cast and the split is meas-

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ured with digital Vernier calliper. The readings are noted atall the three reference points; one anterior and two poster-olateral.

3.Evaluation of Mush bite technique in split cast tech-nique : The records made with Mush bite technique areplaced on casts in the semiadjustable articulator and thediscrepancy at the split is noted and measured with digitalVernier calliper on all the three reference points as de-scribed above.

Evaluation of centric jaw relation by modified Ashs freeplane articulator:

The centric relation records made with intraoraltechnique were taken and seated on the other set of dupli-cated casts, and mounted on the modified Ashs free planearticulator. Care should be taken so that the incisal rodshould remain stabilized in the centre of the graph which isfixed on the incisal table. The plaster is allowed to set. Nowthe centric jaw relation records made with extraoral Gothicarch tracing technique are seated on the mounted cast inthe modified Ash free plane articulator.The shift of incisalrod on the graph paper with extraoral records is noted inanteroposterior and lateral directions. The readings weremeasured with digital Vernier calliper. The extraoral Gothic arch tracing records were takenout from the modified Ashs free plane articulator and cen-tric jaw relation recordings taken with Nick and notchmethod were transferred on the mounted casts on Modi-fied Ashs free plane articulator. The shift of the incisal rodis measured on the graph paper with the help of digitalVerniercalliper, in anteroposterior and lateral directions.Readings (discrepancies) in anteroposterior direction, i.e., Xaxis are taken as negative, whereas readings (discrepan-cies) in lateral direction, i.e., Y axis were taken as positive.Similarly the Nick and Notch method records were re-moved from the modified Ashs free plane articulator andthe centric relation record taken with Mush bite techniquewere transferred on the mounted casts on modified Ashsfree plane articulator. The shift of the incisal rod in thegraph paper was measured with the digital Vernier caliperas explained above.

Fig 1 : Face Bow Record

Fig 2 : Extraoral Gothic arch Tracing

Fig 3 : Nick & Notch Record

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3 Results : This clinical study was performed to evaluatethe more accurate method of recording centric jaw relationin edentulous individuals.

The basic data of the results of this study areshown in annexure from Table III to Table IV. Table III de-picts the measurements noted by using split cast mountingfor various subgroups based on different recording meth-ods. In this table the readings of intraoral subgroup wascategorized under subgroup 1A. This was considered asthe control group. Each measurement was repeated fivetimes and the mean is taken. The other records taken withother three different techniques were categorized undersubgroup1B as reading of extraoral gothic arch tracing,subgroup1C as reading taken with the help of nick andnotch technique and subgroup 1D as the readings takenwith the help of mush bite technique. The measurements atall the three points (two lateral points and one anterior) aretaken as described earlier and mean values were taken.

Statistical Analysis :

Interpretation of results :

In this study, the discrepancy of centric relationrecordings was evaluated among four different recordings,taking intraoral records as control, by using split cast tech-nique. Then, the results were analyzed using the followingstatistical analysis. One way ANOVA test was used to as-sess the significant difference between different groupsbased on arc of closure tracing measurements. Table III depicts the split cast mounting discrepan-cies for various groups based on different methods andalso shows the mean and standard deviation of the varioussubgroups.

Table IV depicts mean and standard deviation ofdifferent measurement among various subgroups evaluat-ed by split cast mounting.

Table Ia shows the statistical evaluation of oneway ANOVA test between different groups. ANOVA re-sults show that the treatment between the columns and theresidual within the columns were statistically significantat1% level.

In Table Ib, NEWMAN KEULS multiple com-parison test depicts the different groups were statisticallysignificant at 1% level such asGroup 1A vs Group 1DGroup 1A vsGroup1CGroup 1Avs Group1B Group 1B vs Group1D Group 1B vsGroup1C Group 1C vs Group I D

Fig 4 : Measurement of discrepancy on semi adjustablearticulator ( lateral )

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Table II : Measurement taken with different recordingtechniques with the help of modified Ashs free plane ar-ticulator (in mm.)

Table II shows the measurements taken with the help ofmodified Ashs free plane articulator. In this table X andY denotes the discrepancy in the anterolateral and lateraldirections. ve sign is taken for only graphical representa-tion which otherwise has no significance.

4 Discussion :

The success of complete denture is determinedby correct recording of maxillomandibular relationship.Centric relation is the repeatable position. Patient will becomfortable to perform all the functional and parafunc-tional movements in this position. Centric relation recordscan be established by various methods. This study wasconducted to evaluate the consistency of various methodsof recording centric relation. In this study the methodsused to record centric jaw relation were(1) Intraoral tracing technique,(2) Extraoral Gothic arch tracing technique,(3) Nick and Notch technique, and(4) Mush bite technique. First two techniques are most frequentlyused in measuring centric jaw relation. According toMichman and Langer the intraoral tracing technique gavebetter results than the commonly used method of an inter-occlusal record, made with the use of wax rims alone.Krishan K,Kapur and A. Albert Yurkstas also told that in-traoral tracing procedureand extraoral tracing procedurewere more consistent as compared to waxregistrationmethod. Tench also quoted a statement and agreed withthe Gysi arrow point technique is the only means thatshould be used in any practice to establish the most im-portant single measurement taken in construction of fulldentures, the centric occlusion relation of mandible tomaxilla.

The intraoral tracing procedure has also beencriticized by many prosthodontists. Their main objectionswere based on the general disadvantages of a central bear-ing point device. Trapozzano stated the use of the centralbearing point is based on the fallacious assumption thatthe central bearing point will produce equalization of pres-sure. Trapozzano maintained that the wax recording meth-od was the most accurate method because of the greaterability to equalize or centralize pressure with this tech-nique. In this study the four techniques were taken forevaluation, two are graphic tracing technique and two arewax recording methods, and intraoral tracing technique istaken as control group. Semi adjustable Dentatus articulator was usedin the study for evaluation of the consistency of differentrecords by using split cast mounting.

The methods of evaluation used in this study were(1) Split cast mounting and(2) Modified Ashs free plane articulator.

The modified articulator concept used in the pre-sent study is modification of the instrument used byKrishan K. Kapur in 1957.

In this present study four different techniques for re-cording centric relation were used; namely,(1) Intraoral graphic tracing (subgroup 1A &2A),(2) Extraoral Gothic arch tracing (subgroup 1B &2B),(3) Nick and Notch method (subgroup 1C &2C) and(4) Mush bite technique (subgroup1D & 2D).Intraoral recordings were taken as control group.

According to the results, among the other threegroups, extraoral groups give the closest reading to thecontrol group, the mush bite records show the maximumdeviation, the nick and notch records fall in between thetwo. Group 1B and 2B show least deviation in the range of1mm.Subgroups 1C and 2C show a deviation upto 3mm andsubgroups 1D and 2D show maximum deviation upto4mm in split cast mounting evaluation. After analysing the data obtained from thestudy, it was found that when the different subgroups werecompared with control subgroup, mush bite technique forregistration of centric relation showed maximum discrep-ancy. The difference was statistically significant withp



The readings of extraoral Gothic arch techniquefound to the closest to the control subgroup. Graph 1 com-pares discrepancy among different subgroups evaluatedwith split cast mounting. Subgroup-1A (control) is closestto subgroup-1B (extraoral Gothic arch tracing). And sub-group-1D shows an average discrepancy of more than4mm. Table II shows the measurements taken with dif-ferent recording techniques with the help of modifiedAshs free plane articulator. In this table it can be observedthat Mush bite record subgroup gave a discrepancy upto amaximum of 3.3mm. And extraoral Gothic arch tracingrecords showed least discrepancy. These findings are inaccordance with the previous literature. Graph 2 showedthe representation of discrepancies of four subgroupswhich are evaluated with modified Ashs free plane articu-lator. In this graphical representation it can be visualizedthat the maximum discrepancy is shown by blue and or-ange colour columns. The positive values describe the dis-crepancy in lateral direction and the negative values in theanteroposterior direction. Control subgroup columns arenot visible because the reading is kept as zero. As describedin table II, extraoral Gothic arch tracing subgroups 2BX and2BY showed least height columns and can be interpreted asleast deviated from control.

5 Summary and conclusion :

An accurate centric jaw relationship recordis important when constructing dentures. It is a three-dimensional record and, to be accurate for a given individ-ual, the relationship, anteroposteriorly and laterally, shouldbe recorded at the occlusal vertical dimension deemed cor-rect for the individual. This study demonstrates a signifi-cant statistical difference between the recordings takenwith intraoral tracing technique and among other sub-groups evaluated by two techniques.The recordings weremade with the extraoral Gothic arch tracing technique val-ues were closer to the control as compared with two othersubgroups in both the evaluations.

Furthermore this study does not show the su-periority of any of method for recording centric jaw rela-tion on one another. This study only shows the deviation ofthe recordings made with four different techniques amongdifferent subgroups.

Accurate records for centric jaw relation can be madewith any of these techniques, but the chances of errors aremore in tactile methods as compared to graphic methods.

ACKNOWLEDGMENT

Authors acknowledge the great help received from thescholars whose articles are cited and included in referencesof this manuscript. The authors are also grateful to authors,editors and publishers of all those articles, journals andbooks from where the literature for this article has beenreviewed and discussed. Authors are grateful to IJOARTeditorial board members and IJOART team of reviewerswhohave helped to bring quality to this manuscript.

References :

1. Earle S. Smith, Vertical dimension and centric jaw rela-tion in complete denture construction. Journal of Prostheticdentistry, January 1958.

2. Yoshiyuki Watanabe. Use of personal computers forGothic arch tracing: Analysis and evaluation of horizontalmandibular positions with edentulous prosthesis. Journalof Prosthetic Dentistry, Volume 82 Number 5.

3. Bouchers Prosthodontic Treatment for Edentulous Pa-tients. 2nd Edition

4. A Albert Yurkstas and Krishan K. Kapur. Factors influ-encing centric jaw relation in edentulous mouths, , Journalof Prosthetic Dentistry 1964 November

5. Garret D. Barret. Reproducible splitcast procedure forremounting the complete denture master cast. The Journalof Prosthetic Dentistry, Volume 54, Issue 5.

6. V. V. Nandini, K. C. Nair, M. C. Sudhakar*, T. S. Podu-val. Comparative evaluation of hight tracer, Chandra trac-er, intraoral tracer, functiograph and checkbite: A clinicalstudy., journal of Indian prosthodontic society, March 2005,Vol 5, Issue 1

7. J. Mishman and A. Langer, Comparison of three methodsof registering centric relation for edentulous patients, Jour-nal of Prosthetic Dentistry, Volume 13, Number 2

Annexure :

Table III: The split cast mounting measurements for vari-ous groups based on different method

Patie

Meas-ure-mentreplica-tion

Group1Amm

Group 1Bmm

Group 1Cmm

Group 1Dmm

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nt

1 A 0 Lt Lat=1.2Rt Lat=1.4Ant=2.3Mean=1.6333

Lt Lat=3.4Rt Lat=3.5Ant=4.2Mean=3.7

LtLat=3.9RtLat=3.8Ant=4.9Mean=4.2

B 0 Lt Lat=1.3Rt Lat=1.3Ant=2.3Mean=1.6333



C 0 Lt Lat=1.4Rt Lat=1.2Ant=2.2Mean=1.6



D 0 Lt Lat=1.2Rt Lat=1.3Ant=2.4Mean=1.63333



E 0 Lt Lat=1.3Rt Lat=1.3Ant=2.3Mean=1.63333



SD

0 0.014898928

0.079580572

0.099713104

NMEA

0 1.6266 3.6599 4.1119

Pa-tient

Meas-ure-mentreplica-tion

Group1Amm

Group 1Bmm

Group 1Cmm

Group 1Dmm



LtLat=3.8RtLat=4.1Ant=5.1Mean=4.

3333B 0 Lt Lat=1.4

Rt Lat=1.4Ant=2.5Mean=1.7666












SD 0 0.043463916

0.036533095

0.027873339

MEAN

0 1.7599 3.85998 4.3398










37









SD 0 0.047141045

0.033350007

0.040824845

MEAN

0 1.5666 3.7999 4.266
















SD 0.043315009

0.043452411

0.036505726

MEAN

1.826 3.83998 4.3596
















SD 0 0.047146347

0.04336125

0.029952162

MEAN

0 1.6666 3.6398 4.4799







38



5333C 0 Lt Lat=1.3

Rt Lat=1.3Ant=2.2Mean=1.6









SD 0 0.052621022

0.043396221

0.043463916

MEAN

0 1.633 3.705 4.5599













0333




SD 0 0.0181341950.0278966490.079593134

0.0181341950.0278966490.079593134

0.0181341950.0278966490.079593134

MEAN

0 1.7531 3.6065 4.1399
















SD 0 0.037925018

0.036522148

0.040824845

39



MEAN

0 1.4465 3.5932 4.4666
















SD 0 0.04944482

0.023571405

0.050532496

MEAN

0 1.673 3.7 4.3199







3










SD 0 0.037998553

0.029834745

0.05054416

MEAN

0 1.6531 3.6865 4.2466

Table IV: Mean and standard deviation of differentmeasurement locations among various groups by splitcast mounting.

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a critical evaluation of different methods of recording

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