Concepts of occlusion in prosthodontics: A literature review,

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1 Review Article Concepts of occlusion in prosthodontics: A literture review, prt I V. Rngrjn, B. Gjpthi, P. B. Yogesh, M. Mohmed Irhim, R. Gnesh Kumr, Prsnn Krthik Deprtment of Prosthodontics, Sri Venkteswr Dentl College nd Hospitl, Thlmur, Chenni, Tmil Ndu, Indi Astrct Occlusion nd its reltionship to the function of the stomtognthic system hve een widely studied in dentistry since mny decdes. This series of rticles descrie out occlusion in the complete denture, fixed prtil denture, nd implnts. Prt I nd II of this rticles series descrie concepts nd philosophies of occlusion in complete denture. So fr, ville reserch hs not concluded superior tooth form or occlusl scheme to stisfy the requirements of completely edentulous ptients with respect to comfort, mstiction, phonetics, nd esthetics. Since then, severl lnced nd nonlnced rticultion concepts were proposed in the literture. A lnced rticultion ppers to e most pproprite ecuse of tooth contcts oserved during nonfunctionl ctivities of ptients. This rticle discusses out evolution of different concepts of occlusion nd occlusl schemes in complete denture occlusion. Key Words: Articultion, complete denture, occlusion Address for correspondence: Dr. B. Gjpthi, Deprtment of Prosthodontics, Sri Venkteswr Dentl College nd Hospitl, Off OMR, Ner Nvlur, Thlmur, Chenni , Tmil Ndu, Indi. E mil: drgjpthi@gmil.com Received: 7 th June, 2015, Accepted: 13 th June, 2015 INTRODUCTION Dentte sttus cn ffect diet, nutritionl sttus, nd generl helth. A complete mxillry denture cn hve n impct on tste nd swllowing ility. Mstictory efficiency in complete denture werers is pproximtely 80% lower thn in people with nturl dentition. Other fctors tht ffect chewing ility include moile teeth, one resorption, reduced sensory perceptions, nd motor impirment. [1] The erly history of the first rtificil tooth is oscure, ut it is known tht 100s of yers go, teeth were crved from Quick Response Code: Access this rticle online Wesite: stone, wood, ivory, nd metl. Humn teeth were lso used in erly dentures. Every time opposing teeth contct there is resultnt force. Although this force my vry in mgnitude nd direction, it must lwys e resisted y supporting tissues. Some dentists elieve there should e cusps on the teeth nd tht they must e in complete hrmony with the dynmics of temporomndiulr joint function. Other dentists elieved tht the teeth should not hve cusps. There re numerous concepts, techniques, nd philosophies concerning complete denture occlusion. [2,3] This is n open ccess rticle distriuted under the terms of the Cretive Commons Attriution NonCommercil ShreAlike 3.0 License, which llows others to remix, twek, nd uild upon the work non commercilly, s long s the uthor is credited nd the new cretions re licensed under the identicl terms. For reprints contct: reprints@medknow.com DOI: / How to cite this rticle: Rngrjn V, Gjpthi B, Yogesh PB, Irhim MM, Kumr RG, Krthik P. Concepts of occlusion in prosthodontics: A literture review, prt I. J Indin Prosthodont Soc 2015;15: The Journl of Indin Prosthodontic Society Pulished y Wolters Kluwer - Medknow

2 CONCEPTS OF COMPLETE DENTURE OCCLUSION [2,3] Rngrjn, et l.: Concepts of occlusion in prosthodontics: A literture review Sttic concept The sttic reltions in occlusion include centric occlusion, protrusive occlusion, right nd left lterl occlusion. All of these reltions must e lnced with the simultneous contcts of ll the teeth on oth sides of the rch t their very first contct. The cuspl inclines should e developed so tht the teeth cn glide from more centric occlusion to eccentric positions without interference nd without the introduction of rotting or tipping forces. Dynmic concept The dynmic concept of occlusion is primrily concerned with opening nd closing movements involved in mstiction. Jw movements nd tooth contcts re mde, s the teeth of one jw glide over the teeth of the opposing jw. Movements of the mndile which occur when the teeth re not in contct re termed s free movements. Occlusl rehilittion in complete denture fll into four occlusl concepts [4] Unlnced rticultion Blnced rticultion Liner or monoplne rticultion Lingulized rticultion. position, the occlusl contct forces re directed towrd the ridges on the working side nd wy from the ridges on the lncing side [Figure 2]. Sers concept [ 5] Sers in 1922 with his chewing memers nd in 1927 with chnnel teeth (oth were nonntomic teeth) developed lnced occlusion y curved occlusl plne nteroposteriorly nd lterlly or with the use of second molr rmp. In centric occlusion, nonntomic teeth will exert contct forces towrd the ridges [Figure 3]. In the right lterl position, the occlusl contct forces directed towrd the ridge on the working side nd towrd the uccl side of the ridge on the lncing side [Figure 3]. Plesure concept [5] In 1937, Dr. Mx Plesure presented n occlusl scheme clled the plesure curve, in which reverse curve is used in the icuspid re for lever lnce, flt scheme of occlusion is set in the first molr re, nd sphericl scheme set in the second molr re y rising the uccl incline to provide for CONCEPTS PROPOSED TO ATTAIN BALANCED OCCLUSION [5] Gysi concept In 1914, 33 cuspl form ws introduced y Gysi. He gve n inclintion of 33 to the cuspl inclines to hrmonize them with the condylr inclintion of 33 to the horizontl. In lterl mndiulr movements, cusps contct ilterlly to enhnce the stility of the dentures. In centric occlusion, the mstictory forces directed towrd the ridges [Figure 1]. In right lterl position, the occlusl contct forces re directed wy from the ridges. In extreme working lterl position, contcts on oth cusps incline, contct force re lso directed outside the ridges [Figure 1]. French concept [5] According to the concept, the occlusl surfce of the mndiulr posterior teeth hd een reduced to increse the stility of the dentures. The mxillry posterior teeth hve slight lingul occlusl inclines of 5 for first premolr, 10 for second premolr, nd 15 for first nd second molrs, so tht lnced occlusion could e developed lterlly s well s nteroposteriorly y the rrngement of teeth on curved occlusl plne. In centric occlusion, hlf of width of mndiulr posterior teeth helps to direct the mstictory forces in uccl direction to the mndiulr residul ridge [Figure 2]. In right lterl Figure 1: () Gysi s concept: In centric occlusion () Gysi s concept: In right lterl position Figure 2: () French s concept: In centric occlusion () French s concept: In right lterl position Figure 3: () Ser s concept: In centric occlusion () Ser s concept: In right lterl position The Journl of Indin Prosthodontic Society Jul-Sep 2015 Vol 15 Issue 3 201

3 Rngrjn, et l.: Concepts of occlusion in prosthodontics: A literture review lncing contct in lterl position. The distl of the second molr cn lso e elevted to produce compensting curve for protrusive lnce [Figure 4]. Plesure rtionlized tht the occlusion should e of specil design due to the instility of the lower denture. Resultnt forces should e directed verticlly nd or lingully. In centric occlusion, contct forces re directed towrd the ridges [Figure 4] nd in right lterl working position, the occlusl forces re directed towrd the lingul side of the lower ridge on the working side nd towrd the uccl side of the lower ridge on the lncing side depending on the inclintion of second molr rmp [Figure 4c]. Frush concept [5] In 1967, Frush gve the Liner occlusl concept, which employed n ritrry rticultor lnce, followed y introrl corrections to otin lnce. A single mesiodistl ridge on the lower posterior teeth contcted flt occlusl surfce of the upper posterior teeth set t n ngle to the horizontl. The intention ws to eliminte deflective occlusl contcts nd incresed stility. In centric occlusion, contct forces directed towrd the ridges ccording to the liner occlusl concept [Figure 5]. In right lterl position, the contct forces towrd the ridge on the working side nd slightly towrd the uccl side of the lower ridge on the lncing side t given inclintion of 6 [Figure 5]. Figure 4: () Plesure curve () Plesure s concept: In centric occlusion (c) Plesure s concept: In right lterl position Figure 5: () Frush s concept: In centric occlusion () Frush s concept: In right lterl position c Hnu s quint [2,3,6] In 1925, Rudolph L. Hnu presented discussion pper entitled, Articultion: Defined, nlyzed, nd formulted [Figure 6]. He elieved rticultion of rtificil teeth ws relted to nine fctors: Horizontl condylr inclintion Compensting curve Protrusive incisl guidnce Plne of orienttion Buccolingul inclintion of tooth xes Sgittl condylr pthwy Sgittl incisl guidnce Tooth lignment Reltive cusp height. He mthemticlly chrted the nine fctors nd listed the lws of lnced rticultion in series of 44 sttements. Hnu comined the originl nine fctors nd reduced them to five. Thielemnn susequently simplified Hnu s fctors in formul for lnced rticultion. [K I]/[OP C OK]. Figure 6: The rticultion quint Where, K = Condyle guidnce. I = Incisl guidnce. C = Cusp height inclintions. OP = Inclintion of the occlusl plne. OK = Curvture of the occlusl surfces. Trpozzno concept [6] Trpozzno reviewed Hnu s five fctors nd decided tht only three fctors were ctully concerned in otining 202 The Journl of Indin Prosthodontic Society Jul-Sep 2015 Vol 15 Issue 3

4 Rngrjn, et l.: Concepts of occlusion in prosthodontics: A literture review lnced occlusion. He eliminted the plne of orienttion since its loction is highly vrile within the ville inner ridge spce. He lso suggested tht the occlusl plne cn e locted t vrious heights to fvor weker ridge [Figure 7]. Trpozzno stted, no need for compensting curve, s it is osolete since the cuspl ngultion will produce lnced occlusion. Boucher concept [2,3,6,7] There re three fixed fctors: The orienttion of the occlusl plne, the incisl guidnce, nd the condylr guidnce The ngultion of the cusp is more importnt thn the height of the cusp The compensting curve enles one to increse the effective height of the cusps without chnging the form of the teeth. The lott concept [2,3,6,7] He stted the lws s follows: The greter the ngle of the condyle pth, the greter is the posterior seprtion The greter the ngle of the overite (verticl overlp), the greter is the seprtion in the nterior region nd the posterior region regrdless of the ngle of the condylr pth The greter the seprtion of the posterior teeth, the greter, or higher, must e the compenstion curve Posterior seprtion compenstion curve to lnce the occlusion requires the introduction of the plne of orienttion [Figure 8] The greter the seprtion of the teeth, the greter must e the posterior teeth. Figure 7: Trpozzno s trid of occlusion Figure 8: The lws of occlusion (Lott) Bernrd levin s concept [2,3,6,7] Bernrd Levin s concept of the lws of rticultion is quite similr to Lott s, ut he eliminted the plne of orienttion [Figure 9]. He hs nmed the four fctors s Qud. The essentils re s follows: The condylr guidnce is fixed nd is recorded from the ptient. The lncing condylr guidnce includes the working condyle Bennett movement, which my or my not ffect lterl lnce The incisl guidnce is usully otined from the ptient s esthetic nd phonetic requirements. However, it cn e modified for specil requirements, e.g., reduction of the incisl guidnce is considered to e helpful when the residul ridges re flt The compensting curve is the most importnt fctor for otining lnce. Monoplne or low cusp teeth must employ the use of compensting curve Cusp teeth hve the inclines necessry for otining Figure 9: Levin s concept lnced occlusion ut nerly lwys re used with compensting curve. The Qud is reltively esy to understnd nd use. The concept of controlling posterior seprtion is n The Journl of Indin Prosthodontic Society Jul-Sep 2015 Vol 15 Issue 3 203

5 Rngrjn, et l.: Concepts of occlusion in prosthodontics: A literture review importnt gol for chieving ilterlly lnced denture occlusion. According to Brien R. Lng tooth forms or molds re of four types [3,4,7] Antomic Nonntomic Zero degree Cuspless teeth. Cuspless teeth re teeth designed without cuspl prominence on the occlusl surfce. DISCUSSION the eccentric movements nd cuse inflmmtion leding to ccelerted one resorption. Though some uthors rgue tht these contcts other thn mstiction re not likely to e mde with ny gret del of force, it is seen tht mny ptients enjoy comfort only when the eccentric lnce is present. Equl contct of ll posterior teeth (centric occlusion) in centric reltion is essentil for the helth of the mucos. [10-12] It hs een determined y studies tht mesured the force necessry to msticte food cn vry from 5 to 175 pounds with nturl teeth. This wide rnge of force is due to person s choice of foods, the condition of the supporting structures of the teeth, integrity of the crown, nd suject s musculr development. [2] Blnced Occlusion is defined s the ilterl, simultneous, nterior, nd posterior occlusl contct of teeth in centric nd eccentric positions. Blnced occlusion in complete dentures is unique, s it does not occur with nturl teeth. If it occurs in nturl teeth, it is considered s premture contct on the nonworking side nd is considered to e pthologic. Usully, ntomic teeth re used to rrnge teeth in lnced occlusion [Figure 10 c]. Nonntomicl teeth cn e used with lncing rmps. [2,3] Importnce The concept ws originlly put forth to enhnce the retention of complete dentures during mstiction. However, it ecme pprent tht even grin of food on the working side elimintes the lnce on the nonworking side. It ws ptly summrized s enter olus, exit lnce y Shepprd. [8] Allen A. Brewer nd Donld C. Hudson hve shown tht complete denture teeth do contct t times during mstiction. However, it will lst for 17 min in dy. [9] Blnce is now deemed necessry during mny excursive movements such s swllowing sliv, closing to reset dentures, nd ruxism performed y ptients in etween mels. Hence, if the lnce is not present, the ses could shift, tip or torque on their foundtions during Figure 10: () Blnced occlusion: In centric occlusion, () lnced occlusion: In right lterl position, (c) lnced occlusion: In protrusive position c The force used in mstiction y denture ptients hs een studied, nd the findings re significnt. In study of 100 denture werers with ges vrying from 26 to 83 yers, the verge force in the molr nd icuspid re during mstiction ws pounds. The force exerted in the incisor re dropped to nine pounds. Gis et l. showed tht the verge closing force during mstiction of complete denture werers is only 11.7 pounds, which is considerly elow the wekest closing force of sujects with nturl teeth. The comprison etween nturl nd rtificil teeth shows tht complete denture werers cn exert only from 10% to 15% of the force of ptient with good nturl teeth. It ppers, therefore, tht the verge complete denture werer hs rely dequte force for the work required during mstiction. [2,13,14] Hence, rrnging modified ntomic teeth in semi djustle rticultor, which cn ccept fce ow trnsfer nd horizontl nd lterl condylr guidnce records from which incisl guidnce cn e estlished for every individul ptient. Bsed on the interocclusl records, selective grinding is done to reduce the occlusl interferences to void deflective forces tht re trnsmitted to the supporting structures. Then thorough ptient eduction, motivtion, nd regulr recll will preserve the helth of the supporting structures for the longer period. Consequences of wering the sme complete dentures for long period re ttrition of rtificil crylic teeth nd loss of occlusion. These conditions result in uneven force distriution nd pthologicl chnges in the underlying orl tissues, which will in turn results in poor ptient comfort, destiliztion of occlusion, inefficient mstictory function, nd esthetic prolems. Ultimtely, ptient my not e le to wer dentures nd will e dignosed s prostheticlly mldptive. The ptients with complete dentures should follow regulr control schedule t yerly intervls so tht n cceptle fit nd stle occlusion cn e mintined. Ptient should e motivted to prctice proper denture wering hits like not wering dentures during the night. 204 The Journl of Indin Prosthodontic Society Jul-Sep 2015 Vol 15 Issue 3

6 Rngrjn, et l.: Concepts of occlusion in prosthodontics: A literture review CONCLUSION Complete edentulism not only hmpers the mstiction, esthetics, ut lso ffects the psychologicl well eing of the ptient. There hs een much controversy out vrious concepts nd the theories put forwrd to chieve occlusion. However, the use of these principles ccording to the individul merits of the cse, hve een neglected. Ech cse should e thoroughly evluted sed on the hrd nd soft tissue ntomy, resorption pttern, neuromusculr control, nd the ptient complince. Finncil support nd sponsorship Nil. Conflict of interest There re no conflict of interest. REFERENCES 1. Plmer CA. Gerodontic nutrition nd dietry counseling for prosthodontic ptients. Dent Clin North Am 2003;47: Winkler S. Essentils of Complete Denture Prosthodontics. 2 nd ed. Delhi: AITBs Pulishers; Boucher CO. Prosthodontic Tretment for Edentulous Ptients. 9 th ed. Delhi: CBS Pulishers; p Lng BR. Complete denture occlusion. Dent Clin North Am 2004;48:641 65, vi. 5. Beck HO. Occlusion s relted to complete removle prosthodontics. J Prosthet Dent 1972;27: Levin B. A reevlution of Hnu s Lws of Articultion nd the Hnu Quint. J Prosthet Dent 1978;39: Zr GA, Bolender CL. Prosthodontic Tretment for Edentulous Ptients. 12 th ed. New Delhi: Mosy; Shepprd IM, Shepprd SM. Denture occlusion. J Prosthet Dent 1968;20: Brewer AA, Hudson DC. Appliction of miniturised electronic devices to study of tooth contct in complete dentures, progress report. J Prosthet Dent 1961;11: Rhn AO, Hertwell CM. Textook of Complete Dentures. 5 th ed. Phildelphi: Le nd Feiger; Swenson MG. Complete Dentures. 1 st ed. St. Louis: C. V. Mosy Co.; p The glossry of prosthodontic terms. J Prosthet Dent 2005;94: Shrry JJ. Complete Denture Prosthodontics. 3 rd ed. St. Louis: Blktison Puliction; Gis CH, Mhn PE, Lundeen HC, Brehnn K, Wlsh EK, Holrook WB. Occlusl forces during chewing nd swllowing s mesured y sound trnsmission. J Prosthet Dent 1981;46: Author Help: Online sumission of the mnuscripts Articles cn e sumitted online from For online sumission, the rticles should e prepred in two files (first pge file nd rticle file). Imges should e sumitted seprtely. 1) First Pge File: Prepre the title pge, covering letter, cknowledgement etc. using word processor progrm. All informtion relted to your identity should e included here. Use text/rtf/doc/pdf files. Do not zip the files. 2) Article File: The min text of the rticle, eginning with the Astrct to References (including tles) should e in this file. Do not include ny informtion (such s cknowledgement, your nmes in pge heders etc.) in this file. Use text/rtf/doc/pdf files. Do not zip the files. Limit the file size to 1 MB. Do not incorporte imges in the file. If file size is lrge, grphs cn e sumitted seprtely s imges, without their eing incorported in the rticle file. This will reduce the size of the file. 3) Imges: Sumit good qulity color imges. Ech imge should e less thn 4096 k (4 MB) in size. The size of the imge cn e reduced y decresing the ctul height nd width of the imges (keep up to out 6 inches nd up to out 1800 x 1200 pixels). JPEG is the most suitle file formt. The imge qulity should e good enough to judge the scientific vlue of the imge. For the purpose of printing, lwys retin good qulity, high resolution imge. This high resolution imge should e sent to the editoril office t the time of sending revised rticle. 4) Legends: Legends for the figures/imges should e included t the end of the rticle file. The Journl of Indin Prosthodontic Society Jul-Sep 2015 Vol 15 Issue 3 205