Occlusion in CD.pptx

Occlusion in CD

1. Occlusion In Complete Denture 1

2. Definitions 2

3. 3 Types of Occlusion 1). Balanced occlusion 2). Monoplane occlusion 3). Lingualized occlusion

4. 4 Objectives of balanced occlusion To improve the stability of denture. To reduce resorption of the residual ridge and soreness. To improve oral comfort & well being of the patient. Occlusal balance – tooth contact Lever balance – tooth position as related to its base of support Balanced occlusion

5. Characteristic Requirements Of Balanced Occlusion All teeth of working side should glide evenly against the opposing teeth No single teeth should produce any interference or disocclusion of the other teeth There should be contacts in the balancing side, but they should not interfere with the smooth gliding movements of working side There should be simultaneous contact during protrusion 5

6. Types of balanced occlusion 1).Unilateral balanced occlusion: 2).Bilateral occlusal balance: A).Protrusive occlusal balance B).Lateral occlusal balance 6

7. 7 1).Unilateral balanced occlusion: Type of occlusion when occlusal surfaces of teeth on one side occlude simultaneously, as a group, with a smooth uninterrupted glide. Not followed during complete denture construction More pertained to fixed partial dentures

8. 8 Bilaterally balanced occlusion: Ferdinand Graf Spee was the earliest to propose -bilateral balanced occlusion. Type of occlusion seen when simultaneous contact occurs on both the sides in centric and eccentric positions. For minimal occlusal balance there should be at least 3 point contact on occlusal plane (2 posterior & 1 anterior).

9. a). Protrusive occlusal balance Usually seen during the protrusion of the mandible. Occlusal contacts are smooth and simultaneous anteriorly and posteriorly 9

10. b).Lateral occlusal balance : Minimal 3 point contact during lateral movement of the mandible. Absent in normal dentition. If allowed while teeth arrangement then the denture would loose its stability due to lever action. 10

11. Hanua’s Quint In 1925, Rudolph L. Hanau presented a discussion paper entitled, “Articulation: Defined, analyzed, and formulated” Nine factors governing the articulation are called as "Laws of articulation” Horizontal condylar guidance Compensating curve Protrusive incisal guidance Plane of orientation Buccolingual inclination of the tooth axis Sagittal condylar pathway Sagittal incisal guidance tooth alignment Relative cusp height 11

12. A balance of five factors is required for balanced occlusion Incisal guidance Condylar guidance Cuspal angulation Plane of occlusion Compensating curve. 12

13. Recorded from the patient using protrusive registration. The interocclusal records are transferred to the articulator and then accommodated to glide freely into position. Significance: Increase in the condylar guidance will increase the jaw separation during protrusion. So in patients with steep condylar guidance incisal guidance is decreased to prevent the posterior jaw separation. Condylar guidance 13

14. Components of condylar guidance A).Protrusive condylar guidance- Guides the forward movement for protrusive balance. Obtained using protrusive records B).Lateral condylar guidance- Guides the sideward or lateral movement of the mandible. Obtained using Hanau's formula or lateral records 14

15. (2).Incisal guidance Defined as “The influence of the contacting surfaces of the mandibular and maxillary anterior teeth on mandibular movements” Determined by the dentist & customized during anterior try-in If overjet is increased, the inclination of incisal guidance is decreased overjet 1/ incisal guidance overbite incisal guidance 15

16. If the incisal guidance is steep, steep cusps or occlusal plane or steep compensatory curve is needed to balance occlusion. Incisal guide angle should be acute with suitable vertical overlap and horizontal overlap to achieve balanced occlusion. 16

17. Denture with steep incisal guidance tend to get displaced Denture with shallow incisal guidance produce less interference 17

18. 3). Plane of occlusion or occlusal plane Defined as “an imaginary surface which is related anatomically to the cranium and which theoretically touches the incisal edges of the incisors & the tips of the occluding surfaces of posterior teeth.” It represents the mean curvature of the surface. Established anteriorly by height of lower canine and posteriorly by height of retromolar pad. Parallel to campers' line Tilting of the plane >10 o is not advisable 18

19. The plane of occlusion can be altered to a maximum of 10 o Plane of orientation can be altered to decrease the posterior tooth separation during protrusion. 19

20. 4). Compensating curve “The anteroposterior and lateral curvatures in the alignment of the occluding surfaces and incisal edges of artificial teeth which are used to develop balanced occlusion” Determined by inclination of posterior teeth and their vertical relationship to occlusal plane. 2 types of curves 1).Anteroposterior compensating curve 2).Lateral compensating curves 20

21. a). Curve of Spee- “ Anatomic curvature established by occlusal alignment of teeth beginning at the tip of lower canine and following the buccal cusps of the premolars and the molars, continuing to the anterior border of the ramus” as described by Graf Von Spee. Significance : When the patient moves his mandible forward, the posterior teeth set on this curve will continue to remain in contact. Thus avoiding disocclusion . 1). Anteroposterior compensating curve- 21

22. Posterior teeth separation when the curve of Spee not incorporated Incorporating the curve Spee will provide posterior tooth contact during protrusion 22

23. Posterior tooth separation during protrusion can be decreased by increasing the curve of Spee. 23

24. 2)Lateral compensating curves a) Monson curve “ The curve of occlusion in which each cusp and incisal edge touches to a segment of the sphere of 8” in diameter with its center at glabella” Runs across the palatal & buccal cusps of maxillary molars. 24

25. b) Wilson’s curve “Curve of occlusion which is convex downwards” Curve that contacts the buccal and lingual cusp tips on each side of the arch It results from inward inclination of the lower posterior teeth, making the lingual cusps lower than the buccal cusps on mandibular arch 25

26. Reverse curve is used in the bicuspid area for lever balance Lateral view with 2nd PM & 1st molar follow the reverse curve c) anti-Monson curve or Reverse curve 26

27. 27 d). Pleasure’s curve A curve of occlusion which in transverse cross-section conform to a line which is convex upward except for the last molar. 1st molar and 2nd premolar buccally tilted (reverse curve) & 2nd molar independently follows Monson’s curve & is lingually tilted

28. 5). Cuspal angulation “Angle made by the average slope of a cusp with the Cuspal plane measured mesiodistally or buccolingually”. It is an important factor that modify the effect of plane of occlusion & the compensating curves. Mesiodistal cusps are reduced to prevent the locking of cusps 28

29. In shallow bite cases : cuspal angle should be reduced to balance the incisal guidance. In Deep bite cases with steep incisal guidance , the jaw separation is more during protrusion .Teeth with high cuspal inclines are required for these cases “ Occlusal reshaping is done after teeth arrangement to produce balanced occlusion.” 29

30. 30