Balanced occlusion.ppt
- 1. 1 Balanced occlusion Dr. veena Saraf
- 2. 2 Occlusion • The static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues (GPT 8) Articulation • The static and dynamic contact relationship between the occlusal surfaces of the teeth during function (GPT 8)
- 3. 3 Balanced Articulation • The bilateral, simultaneous, anterior, and posterior occlusal contact of teeth in centric and eccentric positions (GPT 8)
- 4. 4 Balanced occlusion • “Balanced occlusion in complete denture can be defined as stable simultaneous contact of the opposing upper and lower tooth in centric relation position and a continuous smooth bilateral gliding from this position to any eccentric position within normal range of mandibular function”. (Winkler)
- 5. 5 DIFFERENCES BETWEEN NATURAL AND ARTIFICIAL OCCLUSION Natural teeth Natural teeth function independently and each individual tooth disperses the occlusal load. Malocclusion can be non- problematic for a long time Artificial teeth Artificial teeth function as a group and the occlusal loads are not individually managed. Malocclusions problems
- 6. 6 Natural teeth Non-vertical forces are well tolerated Incising does not affect the posterior teeth. The second molar is the favored area for heavy mastication for better leverage and power. Artificial teeth Non-vertical forces damage the supporting tissues Incising will lift the posterior part of the denture. Heavy mastication over the second molar can tilt or shift the denture base.
- 7. 7 Natural teeth Bilateral balance is not necessary and is usually considered a hindrance Proprioceptive impulses give feedback to avoid occlusal prematurities. This helps the patient to have a habitual occlusion away from centric relation. Artificial teeth Bilateral balance is mandatory to produce stability of the denture. There is no feedback and the denture rests in centric relation. Any prematurities in this position can shift the base.
- 8. 8 REQUIREMENTS OF COMPLETE DENTURE OCCLUSION Stability of occlusion at centric relation position & in area forward & lateral to it Balanced occlusal contacts (tripod contact) during all eccentric movements. Unlocking the cusps mesiodistally to allow for gradual but inevitable settling of the bases due to tissue deformation & bone resorption.
- 9. 9 The control of the horizontal force by buccolingual cusp height reduction . Functional lever balance by favorable tooth to ridge crest position
- 10. 10 REQUIREMENTS OF COMPLETE DENTURE OCCLUSION…. Cutting, penetrating and shearing efficiency of occlusal surface Incisal clearance during posterior functions like chewing.
- 11. 11 REQUIREMENTS OF COMPLETE DENTURE OCCLUSION…. Minimum occlusal contact areas for reduced pressure in comminuting food Sharp ridges or cusps and generous sluice ways to shear & shred food with minimum of force necessary.
- 12. 12 Types of balance or equilibrium • Unilateral balance - Unilateral lever balance - Unilateral occlusal balance • Bilateral balance - Bilateral occlusal balance - Protrusive occlusal balance
- 13. 13 Unilateral lever balance • Equilibrium of the base on its supporting structures , when a bolus of food is interposed between the teeth on one side & a space exists between the teeth on the apposite side
- 14. 14 Unilateral lever balance….. • Placing the teeth so that the resultant direction of force on the working side is over the ridge or slightly lingual to it • Wide area of coverage • Placing the teeth as close to the ridge as possible • Using a narrow buccolingual width occlusal food table as possible
- 15. 15 Unilateral occlusal balance • Occlusal surfaces of the teeth one side articulate simultaneously , as a group ,with a smooth uninterrupted glide
- 16. 16 Bilateral occlusal balance • Equilibrium on both sides of the denture due to simultaneous contact of teeth in centric & eccentric occlusion • Minimum of three contacts to achieve equilibrium
- 17. 17 Bilateral occlusal balance • Incisal guidance • The plane of occlusion • The angulation of teeth (tilt & inclination) • The cusp angulation • The compensating curve • Inclination of the condylar path
- 18. 18 Protrusive occlusal balance • When the mandible moves essentially forward and the occlusal contacts are smooth and simultaneous in the posterior both on right & left sides and on the anterior teeth
- 19. 19 Considerations • The tooth size & position in relation to the ridge size & shape • The extent of denture base coverage • Occclusal balance with stable contacts at the retruded border position & in an area anterior to it
- 20. 20 Considerations…… • Right & left eccentric occlusal balance by simultaneous contacts at the limit of functional & Para functional activity • Intermediate occlusal balance for all positions between centric occlusion and all other functional & Para functional excursions
- 21. 21 Is balanced occlusion is needed ????
- 22. 22 Is “Balance” Necessary? • Tests of Balanced and Non-balanced Occlusion • Trapozzano • 1) No patient preference • 2) Balanced = slightly more efficient • 3) Percentage of patients using eccentric movements during mastication is small JPD 10: 476-487, 1960.
- 23. 23 • Bilateral balanced contact during the terminal arc of closer help to seat the denture in a stable position –lever balance. • Swallowing saliva • Closing to reseat the denture • Clenching
- 24. 24 Advantages of bilateral balance • Better masticatory efficiency • Better stability of denture base • Reduced trauma, improved comfort • The functional movements are possible
- 25. 25 Concepts Proposed to Attain Balanced Occlusion: • Gysi’s Concept(1914): • Arranging 330 anatomic teeth could be used under various movements of the articulator to enhance the stability of the denture.
- 26. 26 French’s concept (1954): • Lowering the lower occlusal plane to increase the stability of the dentures along with balanced occlusion. • He arranged upper first premolars with 50 inclination, upper second premolars with 100 inclination and upper molars with 150 inclination.
- 27. 27 Sears’s concept: • He proposed balanced occlusion for non- anatomical teeth using posterior balancing ramps or an occlusal plane which curves anteroposteriorly and laterally. JPD 1958 ;8; 776
- 28. 28 Pleasure’s concept: • Pleasure introduced a pleasure curve or the posterior reverse lateral curve to align and arrange the posterior teeth in order to increase the stability of the denture. • He used nonanatomic tooth forms & sets the premolars &first molars in an anti-Monson curve , thus the pressure transmitted through the bolus to such an incline creates a resultant force which eliminates the possibility of buccal tipping & thus seats the denture • 1st premolar & 1st molar are set in AntiMonsons curve • 2nd molar in Monson curve ,this combination is pleasure curve
- 29. 29 Frush’s Concept: • He advised arranging teeth in a one-dimensional contact relationship, which should be reshaped during try-in to obtain balanced occlusion.
- 30. 30 Hanau's Laws of Articulation And The Quint (1) Horizontal Condyle Inclination, (2) Compensating Curve, (3) Protrusive Incisal Guidance, (4) Plane Of Orientation, (5) Buccolingual Inclination Of Tooth Axes, (6) Sagittal Condylar Pathway, (7) Sagittal Incisal Guidance, (8) Tooth Alignment, and (9) Relative Cusp Height. A reevaluation of Hanau's Laws of Articulation and the Hanau Quint JPD 1978;3;254
- 31. 31 Hanau's Quint (1) Condylar Guidance, (2) Compensating Curve, (3) Relative Cusp Height, (4) Incisal Guidance, and (5) Plane Of Orientation.
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- 33. 33 Trapozzano Concept • He eliminated the plane of orientation "since its location is highly variable within the available inner ridge space. • He also suggested that the occlusal plane can be located at various heights to favor a weaker ridge.
- 34. 34 Trapozzano’s Triad of Occlusion,
- 35. 35 Boucher Concept (1) there are three fixed factors: the orientation of the occlusal plane, the incisal guidance, and the condylar guidance; (2) the angulation of the cusp is more important than the height of the cusp; and (3) the compensating curve enables one to increase the effective height of the cusps without changing the form of the teeth.
- 36. 36 THE LOTT CONCEPT 1. The greater the angle of the condyle path, the greater is the posterior separation. 2. The greater the angle of the overbite (vertical overlap), the greater is the separation in the anterior region and the posterior region regardless of the angle of the condyle path.
- 37. 37 3. The greater the separation of the posterior teeth, the greater, or higher, must be the compensation curve. 4. Posterior separation beyond the ability of a compensation curve to balance the occlusion requires the introduction of the plane of orientation. 5. The greater the separation of the teeth, the greater must be the height of the cusps of the posterior teeth.
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- 39. 39 Bernard Levin’s concept • Eliminate the plane of orientation. 1. The condylar guidance is fixed and is recorded from the patient. The balancing condylar guidance includes the working condyle Bennett movement, which may or may not affect lateral balance.
- 40. 40 2.The incisal guidance is usually obtained from the patient's esthetic and phonetic requirements. However, it can be modified for special requirements, e.g., a reduction of the incisal guidance is considered to be helpful when the residual ridges are flat
- 41. 41 3. The compensating curve is the most important factor for obtaining balance. Monoplane or low Cusp teeth must employ the use of a compensating curve.
- 42. 42 4. Cusp teeth have the inclines necessary for obtaining balanced occlusion but nearly always are used with a compensating curve.
- 43. 43 The Quad
- 44. 44 References • Boucher’s Prosthodontic Treatment for Edentulous Patient”, 12th edition, Zarb- Bolender. • Boucher’s Prosthodontic Treatment for Edentulous Patient”, 10th edition, Zarb- Bolender, Hickey, Carlsson. • Essentials of Complete Denture Prosthodotics, 2nd Edition, Sheldon-Winkler.
- 45. 45 References ……….. • Complete Denture Prosthodontics – Swenson. • Text Book of Complete Dentures, 5th edition, Rahn, Charles Heartwell. • Complete Denture Prosthodontics – Sharry. • Clinical dental prosthetics, H.R.B.Fenn, K.P.Liddelow , A.P.Gimson
- 46. 46 References ……….. • Journal of Prosthetic Dentistry 1957; 8: 776 • Journal of Prosthetic Dentistry 1978; 39 : 484 • British Dental Journal 1997; 128:1140. • Journal of Prosthetic Dentistry 2000; 84(4):390 • Journal of Prosthetic Dentistry 2001; 85(1):15-19.
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