comparative evaluation of two techniques in achieving

8/2/2019 Comparative Evaluation of Two Techniques in Achieving

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Original Article

Comparative Evaluation of Two Techniques in AchievingBalanced Occlusion in Complete DenturesLt Col M Kumar', Col DSJ D'Souza+AbstractBackground: This study was undertaken to evaluate new teehnique, whieh claims to reduce treatment time while retaining thequality of treatment. The aim of this study was to compare complete dentures made by two techniques: with the use of face bowand without the use of face how.Methods: Twenty edentulous subjects were seleeted and each one received two pairs of complete dentures. Dentures were madefrom duplicated casts and eaeh one followed dift'erent techniques. One teehnique used face-how. Teeth were set using individualizedwax rims as guides. In other teebnique an articulator was used, whieh avoids face-how and teeth were set by the cast-analysismethod. The number of occlusal contacts in centric relation and excursive movements were registered, in addition to this theopinion of patients regarding denture bearing during oral fanctions were taken.Result: Both groups had dentures with balanced occlusion, but the teehnique that avoids face-how presented better results inregard to time taken, esthetics, comfort and stability. Balanced occlusion was provided even without face-how and could be analternative to obtain adequate complete dentures with a better progu08is.Conclusion: For achieving better quality of denture in the form of esthetics, phonetics and fanction in short duration of time; anew teehnique was used to establish balanced occlusion in complete denture prostheses.MJAFI 2010; 66 : 362-366Key Words: Complete dentures; Articolators; Occlusion

IntroductionOcclusion is a factor that is common to all branchesof dentistry. I t is a term generally accepted todescribe the contact relationship of the upper and lowerteeth [1]. Occlusion is defined as the static relationshipbetween incising and masticating surfaces of themaxillary and mandibular teeth. There are numerousconcepts, techniques, and philosophies concerningcomplete denture occlusion. There has been a perplexinglack ofconcern regarding concepts, principles, theoriesand methods of evaluating and understanding themasticatory system. There are many kinds of occlusionwhich are significant in complete prosthodontics.Balanced occlusion refers to the occlusion withsimultaneous contacts of the occlusal surfaces of theteeth on both sides of the arch, regardless of themandibular position.

"A phrase was coined in the mid '60s to explain themovements of dentures that occurred irrespective ofthe occlusal scheme used, which stated "enter bolus,exit balance" [2]. In an artificial dentition, with denturebases ouly really being controlled by muscle activities(albeit to varying degrees), it becomes imperative thatbalancing contacts occur as soon as possible into, around,

and out of centric occlusion, so as to minimize anymovement of the denture bases. Centric occlusion isthe most frequently used position during mastication butalso during swallowing, an action that occurs about 1500times in 24 hours, and so any slide into centric occlusion,the position adopted during swallowing, should bebalanced to minimize denture movement and undueforces being exerted on the base. Other actions alsotake place that can jeopardize even the most idealarrangement of artificial teeth and denture bases. Theocclusal scheme for complete dentures should be one inwhich there are as many contacts around the arch aspossible at all excursive movements away from, andback into, centric occlusion.

One of he most important requirements for successfulcomplete dentures is a balanced articulation. Anadequate occlusal scheme allows better distribution ofmasticatory forces, improves denture efficiency andstability. In order to achieve this, it is necessary toreproduce centric relation and use an adequatearticulator [3]. Articulators reproduce patientcharacteristics with more accuracy [4,5]. However, fullyadjustable articulators are not practical, since theypresent high cost, demand knowledge on equipment and

'Reader, Depar1ment of Dental Surgery, Anned Forces Medical College, Pune-40. +Commanding Officer, 200 MDC, C/o 56 APO.Received: 08.09.09; Accepted : 02.07.10 E-mail: [email protected]


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Comparative Evaluation of Two Techniques in Achieving Balanced Occlusion in Complete Dentures 363long chair side time. On the other hand, nonadjustablearticulators are easy to handle, but fail to obtain abalanced occlusion and dentist spends much time onocclusal adjustments [6,7]. Considering theaforementioned statements, semi adjustable articulatorsseem to present the most adequate effectivenesslhandingrelation for complete dentures. These articulators areeasy to handle and allow a full balanced occlusion duringmandibular excursions, comprising individualcharacteristics of each patient. Face-bow is widely usedto transfer the pati ent's occlusal plane incli nation to thesemi adjustable art iculators. In the same manner,individual compensating curves, following patient pathangles for mandibular movements are estabilished.However, using face bow and estabilishing compensatorycurves could be troublesome in cases of elderly and i l lpatients. Although the useof a face bow presents manytheoretical advantages, they not necessarily producebetter clinical results. The information given in this papermight save time, and thereby allow prosthodontists andgeneral dental off icers in armed forces to rehabilitateand restore a large number of patients. I t would alsohelp in a better understanding of the dynamics ofcomplete denture prostheses and thus improve treatmentand training in this institotion.Material andMethods

In this study two dif ferent techniquesof complete denturesconstructionwere compared. The first used face-bow and asemi-adjustable articulator, HananH2 (HanauEng. CO. BuffaloUSA).The second used a semi-adjustable arti culator (Stratos100, Ivoclar, Liechteinstein), which avoids the use of facebow, using an averagemouoting based upon patient's castsanalysis. Therefore, there is a constant endeavor to explorenewer techniques that would simpli fy procedures and savetime.

Completely edentulous subjects with well formed ridgeswith class Ijaw relation wereselected for this study. Twentysuch subjects were restored with two sets of completedentures, fabricated by each of the two techniquesuodervaluation.After initi al exantinationandthe impressionprocedures the functi onal casts soobtained were duplicatedwith sil icone. Casts obtainedwereseparated into two groupswhich were mouotedon two dif ferent types of semi adjustablearticulators. Casts in technique I were mounted using a facebow ina HanauH2 articulator (Hanau Eng. CO. Buff alo,USA).Casts in technique I I were mouotedwi thout face bow recordin a Stratos 100 arti culator, (Ivociar,Liechtenstein). Followi ngarticulation, teeth setting was carried out using the sametypesof teethset (Ivostar-Gnathostar,Ivocior,Leichtenstein).There after al l t he dentures were processed i n conventionalmanner.TechniqueI

The upper cast wasmouotedby facebow technique, (Fig.I). Lower castswere then al igned andfixed to the arti culatorMIMI, Vol. 66, No.4, 2010

in centric relation posit ion. Horizontal and lateral condyl arguidance was indivi sual ised by following the individualcentric and protrusive relation records. The teeth setti ng wascarried out and occlusion was corrected by means of finegritty stones to obtain a balanced articulation in protrusiveand lateral mandibul ar excursions (Fig. 2).TechniqueI I

Here the castswere mouoted on the articulatorsbasedonaverage values. This technique was specific to this type ofarticulator and was developed to avoid the useof face bow.The lower cast was fi xed to the lower part of he arcon typeofarticulatorby means of a horizontal guide appl iance (Fig. 3),specific to this instrument, which detemtine the arbitraryocclusal plane util izing the pati ent's retro molarpadand labialfrenum, for reference, as i t appeared on the cast. Once thelower cast was fi xed to the arti culator with the plaster, therims incentric relation were placed over the lower cast. Thisal lowed the posi tioning of the upper cast which was fixedwith plaster. Teeth sett ing in this technique was carried outas per he methodof Bi o functional Prosthetic System (Ivoclor,Liechtenstein) with the help of a two dimensional template(Fig. 4). The technique described by the manufacturer usescast analysis, as wel l as the relation between dental archesand anatomic criteria, l ike palate, retro molar pad, rugae onpalate and maxillary tuberosities .These procedures wereperformed observ ing adequate overbite, and to obtainedbalanced occlusion (Fig. 5).

The same operator carried out all procedures. The timetaken i n carrying out various procedures that were notcommon to the two techniques wasnoted. After fabrication,each pair of dentures was tried in pati ent's mouth. Occlusalcontactsof eachpair wereregistered wi th articulating paper,individuallyanda recordwaskept. The patient was suppli edwith one pair of dentures for 10 days before helshe wasrecal led to answer a questi ouoaire. Thereafter the other pairwas i nserted and patient was asked to answer thequestiouoaire after another 10 days. The results concerningthe number of contacts achieved by each techuique andquestiouoaire were statisticall y analyzedby Test of Proportionanalysis and Wi lcoxon Test.Results

In technique II, face bow recording, mounting on thearticulator i n that particular position, gothic arch tracing,recording of centric and protrusive check records andprogrammingof Hanau H2 articulator wereavoided. Hencetime taken in fabrication of complete denture with balancedocclusion in technique II was very less as compare totechnique I.

At denture del ivery appointment, oul y onepair of denturewas given to the patient. Occiusal contacts were registeredwith articulating paper. They were counted at the upperdenture, confirmed at the lower denture and signed. Tominimize errors, contacts were done twice in each person, ina total of 20 samples. Patients were instructedto return after10 days and then answered the Group A part of anappropriatequestionnaire (Annexure I). Thesecondpair of dentures were


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Kumar and D'Souza

Fig. 1 :Cast mounted in theHanau articulator withface-bow (GroupA) . Fig. 2 : Teeth mounting Pig. 3:Horizontalguideof heStratos100articulatorconcluded in the Hanau politionod over the lower cut.articu1ator.

Fig. 4 : Horizontal guide II Pig. 5 : Teethmounting at Strawsrepo&itioDCd to Ihe upper part 100 artiadatorofStratoilOOaDd position thepo!itmiOl" Iowet- teeththen deliveredaDd procedures were repeated. After wearingperiod. patients were asked to choose ODe of those pairs,which were allo signed. Resul ts concerning aboutquestionnaire and number of contacts of groups A and Bwere stati stically analyzedby the Test of Proportion analysisand Wilcoxon Test wi th a significance level of 6%. To accessdifferences between the groups about thesecriteria, WLicoxonTest was used to verify occlusal contacts and Test ofProportionAnalysis wasmade for questionnaire answers.

Occlusal contacts presented a statisticall y signi fi cantdifference betwccn theaverageof GroupsA and B for centricrelation(p::O.OOS) and left.lateralmovement (p::O.OI0),in whicltgroup B presented the greater number of contacts. At rightlateral movement there was a tendency of group B to presenthighernumberof contactl (p=O.065), due to theproximity ofp-value estabUshed of 6%. There was no statisticallysignif icant di f ferencebetwrengroups of dentures (p=O.331)for protrusive movements(Thble 1).Lateral movements weresubdivided into working and non-working sides or thebalancing side, wheren protrusive movements wereseparated in anterior and posterior contac:u. Concerningworking side at lateral movements, dentures in group Apresented worse results than dentures in group B. at ri ghtIak:raJ.movcmco1S (p=(UXl7),but at eft ateral~ herewas no statisticall y signif icamdif ference (p:::::O.I02) as shownin Table 2. Adif f"erentsituation was found in henon-workingsideor the balancing side. n which Group A obtained worseresults at left lateral movement (p:::::O.023), No statisticallysigni f icant dif ferences were observed for right lateral

A na.sun 1Queatlo_aln about complete denture beariagName of the Patient: ........................................... Date: ...............ETaJ.uattoD of Group A dentlll'U ....de byl l l iDI tecbnique IL Comfort durin, wearing period:

[ ] Bm [ ] Saril factory [ ] Very Good2. Stability:[] Om [ J SadlflCtol)'3. BeariD., du.ria. 'PCIll:i.llI :

[ ] B.s [ ] Sadlfactory4. Be.in, durlA, cbewin,:

[ ] B.s [ ] Saril factory D Very GoodEnl Uoa of C~p dCDtara IIlIM1c by Uial tec.llaique D

nate : ...............1. Comfort durin. weMiDJ period:

[ ] Bad [ ] Sallifactory D Very Good2. Stability:

[ ] Bm [ ] Sarilfactory D Very Good3. Be.rinJ; dlJrlq: Jped.l.nl:[ J Bm [ J SariJfactory [ J Very Good

4. BeariDJ Wtinl chom,:[ ] Bad [ ] SallJfactory D Very Good

Preference: Deotwc A Denture BPatietll paIUle: .....................................................movement (p=().233)m .wino ogroupB (Table3). Reganlingprotrusive movement (Table 4), there was no statisticallysignificant difference between denture groups both foranterior (p:::tO.72S) and pOlterior contacts (p:::tO.373).Coolideringall movement! analyzed,denturesfromgroup B,on average. obtained greater number of occlusal contactsthan dentures from group A. According to questionnaire, itwas observed. that denture B had better acceptance bypatients. due to theanawcn "Bad" (p=O.l7) and "Very Good"(p=O .057) there was a statistically significant differencebetween groups A and B (Table5) .After theanalysis, i t couldbe observed that group A wu. composed by dentures madewith faco-bow using technique 1andgroup B, made withoutfac&-bow using technique l l .Discussion

I t was observed. that dentures in Group B. madewithout use of face ~bow presented higher number of

JUAn, \bL 66. No.4, 2010


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Comparative Evaluation of Two Techniques in Achieving Balanced Occlusion in Complete Dentures 365Table 1Number of occlusal contacts in groups A and B

ontacts Centric relation Left lateral movement Right lateral movement Protrusive movementGroup A Group B Group A Group B Group A Group B Group A Group B

Average 11.90 19.10 12.40Variance 6.77 10.10 25.38n 20 20 20p-value 0.005 0.010n=sample sizeTable 2Number of occlusal contacts at working side in groups A andBWorking side Left lateral movement Right lateral movement

Group A Group B Group A Group BAverage 6.50 7.70 6.40 8.40Variance 6.06 8.90 6.71 7.82

n 20 20 20 20p-value 0.102 0.007n=sample sizeTable 3Number of occlusal contacts at balancing side in groups Aand BBalancing side Left lateral movement Right lateral movement

Group A Group B Group A Group BAverage 5.90 7.60 6.20 7.10Variance 6.99 6.93 3.96 3.88

n 20 20 20 20p-value 0.023 0.233n=sample sizeocclusal contacts incentric relation thanGroup A for allmandibular positions. Itmightbe due to technique, whichshows an inherent difficulty: the resin bases have notenough retention at the time of obtaining individualcompensating curves [8,9]. Therefore; the occlusalplanes could be inadequately related to alveolar ri dges.In Group B denture were made using the teeth mountingguideof Stratos 100 articulator, which allows to obtainan arbitrary occlusal plane at the time of teeth setting.This procedure avoids the error due to technique usedin Group I as described above. Both groups presentedsimilar results i n excursive awmovements, establishinga balanced arti culation. Sl ightly better results could beseen for Group B, probably referred to the sameinaccuracy related to the useof standard guides for teethsetti ng. Group B presented better esthetic than GroupA. It could be due to the technique used in setting ofteeth. Group A teeth setting depends on dentist andtechnician's ability to achieve all esthetic requirementsduring wax rims indivi dualization. Group B teeth settingrespects cast analysis, which reproduces individualcharacteristics, despite dental staff 's ability to reproduceesthetics. Group B received more favourable answersMIMI, Vol. 66, No.4, 2010

15.3027.3420

12.60 15.50 15.70 17.4018.93 20.06 17.34 24.9320 20 20 20

0.065 0.331

Table 4Number of occlusal contacts at protrusive movementsbetween groups A and B

rotrusive Anterior Posteriorovement Group A Group B Group A Group B

AverageVariance

np-valuen=sample sizeTable 5

4.603.8220

0.725

4.704.9020

Patients answers regarding denture

11.107.6620

0.373

12.7014.23

20

nswer Group A Group B p-valueBadSatisfactoryVery good

25%35%40%

0%30%70%

0.170.7360.057

thanGrOUpA f or chewing and speaking functions. Thisresult confi rms that comfort, stabil i ty and less stress tothe supporting tissues come from anadequate balancedocclusion [10]. Thus, since Group B presented greateraesthetics and comfort, al l patients preferred denturesfrom this group.Consideri ng the methodology applied and the sampleanalyzed, one can conclude that both groups obtained

balanced occlusion and occlusal contacts i n allmandibular excursions. However, Group B presentedbetter results than Group A, even without face-bow.StratoslOO articulator presented an unexpectedperformance and could be used as a source to obtainbalanced occlusion during complete denture fabrication.Conclusion

Oneof he most important requirements for successfulcomplete dentures is achieving balanced occlusion. Inorder to achieve this, i t s necessary to reproduce centricrelation and use an adequate articulator.Arti culators reproduce pati ent's characteristics wi thmore accuracy. However, fully adjustable articulatorsare not practical, since they present high cost, demandknowledgeof equipment and require long chair side time.

On the other hand, non adjustable articulators are easyto handle, but do not help nachieving balanced occlusion,


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resulting in prolong chair side time spent on occlusaladjustments. Therefore, semi adjustable articulatorsseem to present the most adequate effecti ve tool forcomplete dentures. These articulators have been foundto be easy to handle and allows in achieving a fullbalanced occlusion during mandibular excursions,accommodating individual characteristicsofeach patient.Face bows have been widely used to transfer patient'socclusal plane inclination to semi adjustable arti culators.However, there is not enough evidence to suggest thatthe useof face bow result in increased clinical quality.

I t is concluded that both groups obtained balancedocclusion and occlusal contacts in all mandibularexcursions, however, Group B presented better resultsthan Group A, even wi thout face-bow. Oneof the mostcompelling challenges facing the service prosthodontistis the responsibility to provide quality dentores to anever-increasing patient clientale within the availableconstrains of time and manpower resources. Quiteobviously, the increased amount of time spent intreatment would result in lesser numberof patients whocould be rehabilitated. I t is with this background thatthis stody was undertaken to evaluate new technique,which claimed to reduce treatment time while retainingthe quality of treatment.Conflictsofinterest

This study hasbeen financed by researchgrants from the0/0DGAFMS,NewDelhi.

Intell ectual Contri butionofAuthorsStudy Concept: Lt Col M Kumar

Kumar and D'Souza

Drafting & M anuscri pt Revision: Lt Col M KumarStatistical A nal ysis: Col DSJ D'Souza, Lt Col M KumarStudy Super visi on: Lt Col M Kumar, Col DSJ D'SouzaReferences1. Winkler S. Complete denture: Essentials of complete denture

prosthodontics. 2'" Edition America AITBS Publi shers 2004.2. Boucher CO. Swenson's complete dentures. (jhEdition. CanadaCV Mosby Publications.1970.3 Ash M. Phil osophy of occlusion, Past and Present. DentalClinicsof North America 1995; 39: 233-51.4. Cclenza FW, Nascdkin JF. Occlusion: The state of the art.Quintensence, Chicago 1978.S. Boucher CO. Discussion on laws of articulation. J ProsthetDent 1963; 13: 45-8.6. Lang BR. Complete denture occlusion. Dental ClinicsofNorthAmerica 1996; 40: 85-98.7. Hanau RL. Articulation dermed, analysed and formulated. JAm Dent Assoc 1926; 13: 1694.8. Zarb Bolender. Prosthodonti c Rx for edentulous patients; 12thedition Canada Mosby 2005.9. RamfjordSP. Thesignificanceof recent researchon occlusionfor the teaching and practice of dentistry. J Prosthet Dent1966; 16: 96-103.10. Sharry JJ. Complete Denture Prosthodontics; 2'" editionEngland McGraw-Hill Book Company 1962.

ERRATUMCase Report: "A Case ofIntravaginal Foreign Body" MJAFI July 2010; 66 266-8.For: Sqn Ldr N Magon, Clinical Tutor (Deptof Obstetric & Gynaecology), AFMC, Pune-40.Read: Sqn Ldr N Magon, Resident (Dept of Obstetric & Gynaecology), AFMC, Pune-40.The error is regretted.

M IM I , Vol. 66, No.4, 2010

comparative evaluation of two techniques in achieving

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