Lingualized occlusion in rdp

Lingualized

1. Lingualized Occlusion For Removable Prosthodontics Presented by: Dr. Mujtaba Ashraf MDS II Becker CM, Swoope CC, Guckes AD J Prosthet Dent 1977;38:601-8 Journal Club Presentation 14 July 2017 Dr. Mujtaba 1

2. Introduction 14 July 2017 Dr. Mujtaba 2

3. The literature is filled with discussions of the various types of occlusal forms and posterior tooth arrangements. The search for the ideal denture occlusion has been going on for almost two centuries in an effort to find the tooth form which provides maximum denture stability and masticatory efficiency without compromising the health of the underlying bone . 14 July 2017 Dr. Mujtaba 3

4. Prof. Alfred Gysi was first to design and patent “ Cross-Bite Posterior Teeth ” in 1927 . Each maxillary tooth featured a single, linear cusp that fit into shallow mandibular depression. So the Concept of lingualized occlusion was introduced by A. Gysi in 1927. Maxillary posterior teeth featured single, linear cusps that fit into shallow mandibular depressions. 14 July 2017 Dr. Mujtaba 4

5. Today , the available occlusal forms can be classified into three major groups : anatomic- 30 degree cusps, semianatomic - 20 degree cusps , nonanatomic or cuspless - 0 degree cusps 14 July 2017 Dr. Mujtaba 5

6. Advantages of various cusp forms suggested in the literature Cusp Form Advantages Anatomic occlusion Penetrates food more easily Resists the rotation of denture bases through cusp interdigitation Provides better esthetics Acts as a guide for proper jaw closure Non-anatomic occlusion Does not lock the mandible in one position Permits the use of less time consuming techniques Minimizes horizontal stress because of the absence of inclined planes Adapts easily to Classes II and III jaw relations More easily adjusted after changes in vertical and horizontal relations Easier to arrange in crossbite 14 July 2017 Dr. Mujtaba 6

7. Cusp Form Disadvantages Anatomic occlusion More occlusal disharmony during settling and difficult to correct by adjustment Precise jaw closure and base stability required for interdigitation Increased horizontal forces Difficult to adapt to abnormal jaw relationships Non-anatomic occlusion Poor esthetics Decreased masticatory efficiency More difficult to obtain balanced occlusion Psychological Disadvantages of various cusp forms suggested in the literature 14 July 2017 Dr. Mujtaba 7

8. LlNGUALlZED OCCLUSION 14 July 2017 Dr. Mujtaba 8

9. Lingualized occlusion is an attempt to maintain the esthetic and food-penetration advantages of the anatomic form while maintaining the mechanical freedom of the non-anatomic form. The lingualized concept utilizes anatomic teeth for the maxillary denture and modified non-anatomic or semi-anatomic teeth for the mandibular denture Lingualized occlusion should not be confused with placement of the mandibular teeth lingual to the ridge crest, as suggested by several authors . 14 July 2017 Dr. Mujtaba 9

10. Lingualized Occlusion has been defined as “a form of denture occlusion that articulates the maxillary lingual cusps with the mandibular occlusal surfaces in centric, working, and nonworking mandibular positions . GPT-9 14 July 2017 Dr. Mujtaba 10

11. EVOLUTION Gysi was first to report the biomechanical advantages of lingualized tooth forms (1927). The basic concepts of lingualized occlusion were first suggested by Payne (1941). Pound discussed a similar occlusal concept and used the term “ lingualized occlusion” (1973). Ortman , Murrell, Becker, and Kelly provided additional support for this occlusal concept (1977). Parr GR, Loft GH. The occlusal spectrum and complete dentures. Compend Contin Educ Dent 1982; 3:241-50 Parr GR, Ivanhoe JR. Lingualized occlusion:an occlusion for all reasons. Dent Clin North Am 1996;40:103-12 14 July 2017 Dr. Mujtaba 11

12. Gysi designed and patented “Cross-Bite Posterior Teeth” in 1927. Each maxillary tooth featured a single, linear cusp that fit into a shallow mandibular depression. These teeth were reasonably esthetic, easy to arrange, and encouraged vertical force transmission via their mortar-and-pestle anatomy. Gysi’s Cross-bite Posterior Teeth Gysi A. Special teeth for cross-bite cases.Dent Digest 1927;33:167-71 14 July 2017 Dr. Mujtaba 12

13. By 1935, Dr. FA French had patented his “Modified Posterior Teeth ”. The maxillary teeth featured shallow fossae , while the mandibular teeth displayed narrow, planar occlusal surfaces. French FA. The problem of building satisfactory dentures. J Prosthet Dent 1954;4:769-81 Dr. French’s Modified Posterior Teeth 14 July 2017 Dr. Mujtaba 13

14. PAYNE’S CONCEPT This changed in 1941, when Dr. SH Payne introduced a more cogent form of lingualized occlusion. According to Payne’ article, a mortar-and-pestle arrangement was created via judicious recontouring of 30-degree teeth. Payne SH. A posterior set-up to meet individual requirements. Dent Digest 1941;47:20-2 14 July 2017 Dr. Mujtaba 14

15. The maxillary lingual cusps maintained contact with the mandibular teeth in eccentric movements. In contrast, the maxillary buccal cusps did no contact to the opposing teeth during mandibular movements. Payne SH. A posterior set-up to meet individual requirements. Dent Digest1941;47:20-2 14 July 2017 Dr. Mujtaba 15

16. POUND’S CONCEPT Pound also championed lingualized occlusion in his articles and presentations . Pound used maxillary teeth having cusp angles greater than 30 degrees in conjunction with mandibular teeth having cusp angles of 20 degrees or less. He carefully reshaped mandibular fossae to produce cross-arch balance. Pound E. Utilizing speech to simplify a personalize denture service. J Prosthet Den1970;24:586-600 14 July 2017 Dr. Mujtaba 16

17. Pound ensured that maxillary buccal cusps did not contact mandibular teeth during eccentric mandibular movements . He accomplished this by reducing the facial surfaces of the mandibular posterior teeth rather than elevating the buccal cusps of the maxillary teeth. Though the method for eliminating maxillary buccal contact was dissimilar, the mechanical results were nearly identical to those described by Payne . 14 July 2017 Dr. Mujtaba 17

18. OBJECTIVE In a lingualized occlusion scheme, the objective is the elimination of buccal cusp contacts in order to alleviate lateral stresses or lateral dislodging forces . 14 July 2017 Dr. Mujtaba 18

19. The lingual cusps of the upper posteriors make contact in centric relation in the central fossae of the lower posteriors. 14 July 2017 Dr. Mujtaba 19

20. The buccal cusps are out of contact ; however the lingual cusps are in contact in centric, working and balancing movements. For this reason, all the stresses created during working and balancing motions are of a downward nature, thus creating stability. Working Side Balancing Side 14 July 2017 Dr. Mujtaba 20

21. INDICATIONS FOR LINGUALIZED OCCLUSION Lingualized occlusion can be used in most denture combinations. It is particularly helpful when the patient places high priority on esthetics but non-anatomic occlusal scheme is indicated because oral conditions such as severe alveolar resorption, a Class II jaw relationship , or displaceable supporting tissue. If the non anatomic occlusal scheme is used, esthetics in the premolar region are compromised. With Lingualized occlusion, the esthetic result is greatly improved while still maintaining the advantages of a non-anatomic system. 14 July 2017 Dr. Mujtaba 21

22. A monoplane occlusal scheme limits esthetic results in the premolar region. 14 July 2017 Dr. Mujtaba 22

23. A lingualized occlusion provides improved esthetics in the premolar region. 14 July 2017 Dr. Mujtaba 23

24. Lingualized occlusion also can be used effectively when a complete denture opposes a removable partial denture. Patients having parafunctional habits, so that reduced amount of horizontal forces are transmitted to supporting tissues. 14 July 2017 Dr. Mujtaba 24

25. Implant-supported overdentures to eliminate lateral forces that can rock abutments loose over time. 14 July 2017 Dr. Mujtaba 25

26. PRINCIPLES 1. Anatomic posterior (30 or 33 degree) teeth are used for the maxillary denture. Tooth forms with prominent lingual cusps are helpful. 2. Non-anatomic or semi-anatomic teeth are used for the mandibular denture. 14 July 2017 Dr. Mujtaba 26

27. Either a shallow or flat cusp form is used. A narrow occlusal table is preferred when severe resorption of the residual ridges has occurred. 3. Maxillary lingual cusps should contact mandibular teeth in centric occlusion. 14 July 2017 Dr. Mujtaba 27

28. Modification of the mandibular posterior teeth is accomplished by selective grinding which is always necessary regardless of specific tooth or material. Selective grinding smooth the central fossae of the mandibular teeth, lowers marginal ridges, and forms slight buccal and lingual inclines 14 July 2017 Dr. Mujtaba 28

29. The mandibular buccal cusps should not contact the upper teeth in centric occlusion , as is customary with usual anatomic tooth placement. It is helpful to slightly rotate the maxillary posterior teeth buccally to allow for slight clearance of the buccal cusps in the working position and to reduce the need for extensive grinding 14 July 2017 Dr. Mujtaba 29

30. 4. Balancing and working contacts should occur only on the maxillary lingual cusps. 14 July 2017 Dr. Mujtaba 30

31. Working Side Balancing Side 14 July 2017 Dr. Mujtaba 31

32. Reduction of antero -posterior interferences on the mandibular teeth may be necessary in order to provide a range of balanced occlusion in the protrusive position. Selective grinding for should be done only on the mandibular teeth so that lateral balancing contacts and the vertical dimension of occlusion are not changed . 14 July 2017 Dr. Mujtaba 32

33. A wide variety of cusped and non-cusped tooth forms may be used to create arrangements that may be considered to be lingualized occlusion . Generally, maxillary teeth with cusp angles of ≥30 degrees are opposed by mandibular teeth displaying cusp angles of ≤20 degrees. Some of the most popular combinations include 30- to 33-degree cusp designs for maxillary teeth and 0-degree cusp designs for mandibular teeth. Balancing Working 14 July 2017 Dr. Mujtaba 33

34. Advantages of L ingualized Occlusion Most of the advantages attributed to both the anatomic and non-anatomic forms are retained. Cusp form is more natural in appearance compared to non-anatomic tooth form . Good penetration of the food bolus is possible. Bilateral mechanical balanced occlusion is readily obtained for a region around centric relation. Vertical forces are centralized on the mandibular teeth. 14 July 2017 Dr. Mujtaba 34

35. Summary Lingualized occlusion provides a useful combination of several occlusal concepts. Many advantages of anatomic and non-anatomic occlusions are retained. Adjustment to compensate for minor changes in vertical and centric relation is readily accomplished. Satisfactory occlusion is easily obtained, and balanced occlusion can be accomplished. The lingualized occlusal concept is not a panacea, and all other procedures still must be carefully executed. 14 July 2017 Dr. Mujtaba 35

36. References 1. Sears, V. H. : Chewing Members, J. PROSTHET. DENT. 1: 761-763, 1951. (Historical reprint of an original paper presented in 1922.) 2. Hall, R. E.: The Inverted Cusp Tooth, J. Am. Dent. Assoc. 18: 2366-2368, 1931. 3. Hardy, I. R.: The Development in the Occlusal Patterns of Artificial Teeth, J. PROSTHET. DENT . 1: 14-28, 1951. 4. Sears, V. H.: Thirty Years of Non Anatomic Teeth, J. PROSTHET. DENT. 3: 596-617, 1953 . 5. Rapp, R.: The Occlusion and Occlusal Patterns of Artificial Posterior Teeth, J. PROSTHET. DENT . 4: 461-480, 1954. 14 July 2017 Dr. Mujtaba 36

37. 14 July 2017 Dr. Mujtaba 37