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Stress treatment theory

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Stress treatment theory

  1. 1. Marwan m. el said BDS. MSc
  2. 2. Stress treatment theorem
  3. 3. Stress treatment theorem • Focus on evaluating biomechanical stress • Understanding the relationships of stress and treatment systems • Anticipate the short and long term effect of stress on the implant therapy
  4. 4. Stress treatment theorem 1. Prosthesis design 2. Patient force factors 3. Bone density 4. Key implant positions and number 5. Implant size 6. Available bone 7. Implant design
  5. 5. Prosthesis design • Patients want teeth not implants • The final result should be visualized prior to implant therapy • Partially edentulous patients are planed as fixed prosthesis while completely edentulous are planed either as fixed or removable • It is often necessary to modify the mouth or modify the mind of the patient
  6. 6. •FP-1 •FP-2 •FP-3 Fixed prosthetics •RP-4 •RP-5 removable prosthetics
  7. 7. FP-1
  8. 8. FP-2
  9. 9. FP-3
  10. 10. RP-4
  11. 11. RP-5
  12. 12. Patient force factors
  13. 13. Normal forces 1-Bite force Perpendicular to the occlusal plane Short duration Force on each tooth 20 to 30 psi Maximum bite force 50 to 500 psi
  14. 14. Normal bite force 2-Perioral forces More constant Lighter Horizontal Maximum when swallowing 3 to 5 psi Brief total swallowing time 20 min/day
  15. 15. Parafunctional • Local • Systemic • Psychological • Occupational • Involuntary • Voluntary
  16. 16. Patient force factors A. Bruxism B. Clenching C. Tongue thrust D. Crown height E. Masticatory dynamics F. The opposing arch
  17. 17. Bruxism
  18. 18. Clenching
  19. 19. Tongue thrust
  20. 20. Crown height • Crown height space (CHS) measured from the crest of the bone to the occlousal plane • The ideal CHS for implants 8 to 12 mm for fixed restorations • Over 12 mm may require hypred restoration Or removable restoration • Crown height is a vertical cantilever
  21. 21. Masticatory dynamics • Old vs. young • Female vs. male • Large built vs. small built • Normal occlusion vs. parafunctional • Neuromuscular disturbance
  22. 22. The opposing arch Removable partial denture Fixed partial denture Natural teeth Implant
  23. 23. Bone density
  24. 24. Bone density • Directly related to implant successes • Four types of bone were identified • Progressive loading change the amount of bone density around the dental implants
  25. 25. Etiology of variable bone density • Do you remember Wolff ? • The mandible Vs. maxilla • Bone density location
  26. 26. Misch bone density classification
  27. 27. Radiographic bone density
  28. 28. Key implant positions and number
  29. 29. Key implant positions and number • Some implant positions are more important than others • The most important abutment is the terminal abutment • Cantilevers are force magnifiers
  30. 30. 4 golden laws of multiple implant placement 1 •No cantilever 2 •No three adjacent pontics 3 •Canine molar rule 4 •Arch dynamics
  31. 31. No cantilever
  32. 32. No three adjacent pontics
  33. 33. Canine molar rule
  34. 34. Implant size
  35. 35. Forces applied to dental implant shear tension compression
  36. 36. force duration magnification direction type
  37. 37. Length width Implant surface area
  38. 38. Long implants Short implants
  39. 39. • Advantages of shorter implants Less bone grafting in hieght – Less time for treatment – Less cost – Less discomfert Less surgical risk of – Sinus perforation – Paresthia – Osteotomy truma – Tooth damage Surgical ease – Decreased inter arch space – Less inventory / less cost
  40. 40. • Implant size manipulation Increase the diameter Splint together Decrease crown height Increase implant surface area OD VS FPD Minimize lateral forces Improve bone density
  41. 41. Implant diameter Narrow Wide
  42. 42. • Surgical advantages of wide implants – Surgical rescue implant – Failed implant/immediate – Tooth extraction /immediate • Loading advantages – Increase surface area – Compensate for unfavorable forces – Compensate for poor bone density – Increase surface area for short implants
  43. 43. • Disadvantages of wide implants Bone trauma Decreased facial bone thickness Stress shielding Increased surgical failure Damage to the adjacent tooth
  44. 44. • Implant diameter criteria Esthetics • Size of the tooth (minimum implant size) • Adjacent tooth- inter proximal bone (maximum implant size) • Faciopalatal bone (maximum implant size) Function • Functional surface area • Fatigue strength
  45. 45. Available bone
  46. 46. • Division A bone is three-dimensionally abundant for the ideal implant insertion 5 mm or more in width  12 mm or more in height  7 mm or more in length  Less than 30° in angulation  15 mm or less in crown height
  47. 47. • Division B (barely adequate) bone  2.5–5 mm in width (B+: 4–5 mm; B−: 2.5–4 mm) 12 mm or more in height 6 mm or more in length Less than 20° in angulation 15 mm or less in crown height.
  48. 48. • Treatment options Modify by osteoplasty to permit the placement of root form implants 4 mm or greater in width.  Insert a narrow root form implant. Modify the existing Division B bone into Division A by augmentation.
  49. 49. • Division C (compromised bone)  0–2.5 mm in width (C-w bone)  Less than 12 mm in height (C-h bone)  More than 30° in angulation (C-a bone)  More than 15 mm in crown height.
  50. 50. Treatment options : (1) Osteoplasty (2) Root form implants (3) Subperiosteal implants (4) Augmentation procedures (5) Ramus frame implants (6) Transosteal implants
  51. 51. Division D (Deficient Bone) • Severe atrophy • Basal bone loss • Flat maxilla • Pencil thin mandible
  52. 52. Treatment options : • most difficult to treat in implant dentistry. • Autogenous bone grafts to upgrade the division are strongly recommended before any implant treatment. • Once autogenous grafts are in place and allowed to heal for 5 or more Months the case should be evaluated for implant placement .
  53. 53. Implant design

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