Developments in the Occlusal patterns of artificial Teeth / orthodontic continuing education

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Developments in the Occlusal patterns of artificial Teeth / orthodontic continuing education

  1. 1. THE DEVELOPMENTS IN THE OCCLUSAL PATTERNS OF ARTIFICIAL TEETH INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. CONTENTS  INTRODUCTION.  SPECIFICATIONS OF POSTEROIR ARTIFICIAL TEETH- BY SEARS AND PLEASURE.  GROUPS OF ARTIFICIAL TEETH.  HISTORYOF DEVELOPMENT.  EXPERIMENTAL STUDIES.  CONCLUSION. www.indiandentalacademy.com
  3. 3. INTRODUCTION  The occlusal surfaces are the primary concern in selecting the form of the posterior teeth.  According to Gysi “ Artificial teeth can be properly formed only by the application of the knowledge of the conditions under which they must function .” www.indiandentalacademy.com
  4. 4. SPECIFICATIONS FOR POSTERIOR TEETH FORM-SEARS AND PLEASURE 1. No interferring projections between centric and eccentric tooth positions to restrict mandibular movements. 2. It is possible to set them in cross-bite relationship if necessary. 3. Working occlusal area should be lingually placed from the ridge crest. 4. It should provide bilateral balance without sacrificing ideal angle of working occlusal surface www.indiandentalacademy.com
  5. 5. SPECIFICATIONS(CONT) 5. Bulk of teeth should be sufficient to make satisfactory contact with tongue and fill buccal vestibule. 6. All working surfaces should be at right angles to the direction of closing force. 7. Teeth may be altered by grinding without losing their mechanical (or) esthetic advantage 8. Occusal form should permit compensation for change in ridge relation. www.indiandentalacademy.com
  6. 6. SPECIFICATIONS(CONT) 9. No wells or hollows in which food can pack. 10.They must present degree of cutting efficiency required to cut fibrous foods and thus diminishing trauma to tissues. 11. Relation of opposing occlusal surfaces must not interfere with arrangement of anterior teeth. www.indiandentalacademy.com
  7. 7. GROUPS OF ARTIFICIAL TEETH  Based on occlusal form of posterior teeth they are Grouped into 2 types  ANTOMIC AND NON-ANTOMIC TEETH www.indiandentalacademy.com
  8. 8. ANATOMIC TEETH 1. Simulate natural tooth form. 2. Have cuspal height with varying cuspal inclines. 3. Three dimensional intercuspation 4. More efficient in mastication. 5. Increased horizontal forceswww.indiandentalacademy.com
  9. 9. NON-ANTOMIC TEETH 1. Doesn’t simulate natural teeth form. 2. No cuspal height with flat cuspal form. 3. Two dimensional Intercupation. 4. Not efficient in mastication. 5. Decreased horizontal forces but increased vertical forces www.indiandentalacademy.com
  10. 10. 18th century  In olden days artificial teeth were carved from stone, wood, ivory, metal and even human teeth used to replace lost tooth.  As these are not esthetic,long lasting and dosen’t perform masticatory function well, search for an ideal artifical tooth has began. www.indiandentalacademy.com
  11. 11. HISTORY OF DEVELOPMENT  ANATOMIC TEETH 1. Gysi- 1913-1928 2. Sear’s- 1928 3. Avery- 1930 4. French’s- 1935 5. McGrane’s- 1936  NON-ANTOMIC TEETH 1. Hall- 1929 2. Myerson- 1929 3. Nelson- 1934 4. Swenson- 1939 5. Hardy- 1946 www.indiandentalacademy.com
  12. 12. TRUBYTE TEETH-Dr.Alfred Gysi  FEATURES: Teeth had cuspal angle of 33 degrees, Transverse ridges present and were intended for tight interdigitation www.indiandentalacademy.com
  13. 13. TRUBYTE TEETH-1913  PRINCIPAL: Designed to function harmoniously with incisal and condylar guidances simulating natural tooth.  ADVATAGES: 1.Simulated natural tooth form.  DISADVATAGES: 1.Dislodgement of denture in severly resorbed ridges. www.indiandentalacademy.com
  14. 14. CROSS-BITE TEETH(GYSI)-1928  Principle: “mortar and pestle” Action by Brenner and payne. -Features: Buccal cusps are grinded.  Disadvantage: Shifting of denture bases . www.indiandentalacademy.com
  15. 15. CHANNEL TEETH-SEAR’S(1928)  FEATURES: Channels run mesio-distally, with working occlusal surface 1mm to 1.5mm width. The buccal and lingual plane fall away from central horizontal fossa. www.indiandentalacademy.com
  16. 16. SEAR’S CHANNEL TEETH  PRINCIPLE:  For efficient cutting and to prevent denture base instability channels were created on occlusal surfaces running mesio-distally  ADVANTAGES: Free movement in antero-posterior direction.  DISADVATAGES: 1.Lock and interference in lateral excursions. 2.No food table. www.indiandentalacademy.com
  17. 17. AVERY BROTHER’S-SCISSOR-BITE TEETH(1930)  FEATURES:  No cuspal inclines bucco-lingually.  Definite interlock antero-posteriorly to prmote shearing action www.indiandentalacademy.com
  18. 18.  PRINCIPLE:  To promote shearing action buccal and lingual inclines were eliminated, which is an outstanding feature of AVERY brothers teeth.  ADVATAGE:  Shearing of food in lateral excursions  DISADVATAGE:  Food accumulates in buccal vestibule  When food floats over to the balancing side it is subjected to rubbing action not shearing action. www.indiandentalacademy.com
  19. 19. FRENCH’s posterior teeth(1935)  FEATURES:  Eliminated buccal cups.  No antero-posterior cuspal inclines.  Central groove running in mesio-dista sirection but with very shallow bucco-lingul inclines to reduce lateral thrust www.indiandentalacademy.com
  20. 20.  PRINCIPLE:  Design placed the occlusal forces lingually.  ADVANTAGE: 1.Greater denture stability.  DISADVANTAGE: 1.Did not provide for balancing contacts in either lateral or prorusive excursions. www.indiandentalacademy.com
  21. 21. McGRANE’S CUVED CUSP(1936)  FEATURES:  Antero-posterior lock without buccal and lingual inclines www.indiandentalacademy.com
  22. 22.  PRINCIPLE: Curved cusp teeth are designed to lock antero- posteriorly and free laterally in an arc corresponding to an arbitary radius from each vertical rotational axis of the right and left condyles.  ADVATAGES: 1.NO TRAUMA TO THE TISSUES ON WORKING SIDE. 2.Shear food in harmonius with lateral condylar guidance.  DIADVANTAGES: 1.NO METHOD FOR ADJUSTMENT IN CASES WHERE INTERFERENCES OCCURS. 2.No attempt made to get balanced occlusion. www.indiandentalacademy.com
  23. 23. HALL-INVERTED CUSP(1929)  FEATURES:  No cuspal inclinations, flat occlusal surface,cutting blades incorporated in occlusal carvings, sluiceways are included. www.indiandentalacademy.com
  24. 24. www.indiandentalacademy.com
  25. 25. INVERTED CUSP TEETH  PRINCIPLE:  Function by simulating the action of machine used to design cusps.  ADVANTAGE: 1.Decreased horizontal forces on teeth.  DISADVANTAGES: 1.Centrifugal force which clears the cups of debris is not present in mouth and lower teeth tend to retain teeth. www.indiandentalacademy.com
  26. 26. NELSON- CHOPPING BLOCK-(1934)  FEATURES:  Flat occlusal surfaces with numerous ridges.  Ridges on mandibular teeth run transeversly and in maxilla they rum mesio-distally.  ADVANTAGES:  Ridges run perpendicular to one another in contact an efficient shredding and cutting action was claimed. www.indiandentalacademy.com
  27. 27. SWENSON-NONLOCK-(1939)  FEATURES:  These are essentially flat teeth with sluiceways for shredding and allowing food to clear the occlusal table.  ADVATAGES:  They provided balancing contacts. www.indiandentalacademy.com
  28. 28. HARDY’S-VO (1946)  Vitallium occlusal (VO) metal insert placed in upper and lower teeth  A narrow zigzag of vitallium ribbon was embeded on the occlusal surface and ran mesio-distally establishing a narrow,flat, convoluted metal surface that was raised slightly above encasing the resin www.indiandentalacademy.com
  29. 29. HARDY’S-VO- TEETH  ADVATAGES: 1.Better chewing efficiency.  DISADVANTAGE: 1.Tongue irritation due to metal insert.  MODIFIED HARDY’ TEETH:  Raising the plastic which is molded around the insert so it is high enough on lingual surface to prevent tongue making contact. www.indiandentalacademy.com
  30. 30. EXPERIMENTAL STUDIES TO EVALUATE CHEWING EFFICIENCY OF DIFFERENT ARTIFICIAL TEETH  THOMPSON- In 1937 tested 33 degree cusp teeth,20 degree teeth, Hall’s teeth, and Sear’s channel teeth. He found Sear’s channel teeth were least efficient .  SOBOLICK-In 1938 tested on duplicate dentures with different occlusal forms for each individual and ranked their effeciency in following order,Halls inverted cusp,true- kusp,french’s and lastly tru-byte teeth. www.indiandentalacademy.com
  31. 31. OTHER POSTERIOR TEETH WITH DIFFERENT OCCLUSAL FORMS  MYERSON; SHER-CUSP- 1951  COOK ; COOKS METAL- 1952  DEVAN ; NEUTROCENTRIC- 1954  BRADER ; CUTTER BAR - 1957  FRUSH ; LINEAR OCCLUSAL- 1967 www.indiandentalacademy.com
  32. 32. CONCLUSION  As various posterior teeth different occlusal forms has evolved, It is the clinician responsibility to choose suitable teeth with occlusal form for a particular patient keeping following in mind  1. Health and preservation of supporting tissues. 2. Denture stability. 3. Forces directed to the ridge. 4. Masticatory efficiency. 5. Esthetics and phonetics. www.indiandentalacademy.com
  33. 33. For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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