Stress treatment theory in implant therapy

1. Marwan m. el said
BDS. MSc

2. Stress treatment theorem

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. 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. 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. •FP-1
•FP-2
•FP-3
Fixed
prosthetics
•RP-4
•RP-5
removable
prosthetics

7. FP-1

9. FP-2

11. FP-3

17. RP-4

23. RP-5

33. Patient force factors

34. 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

35. Normal bite force
2-Perioral forces
More constant
Lighter
Horizontal
Maximum when swallowing 3 to 5 psi
Brief total swallowing time 20 min/day

36. Parafunctional
• Local
• Systemic
• Psychological
• Occupational
• Involuntary
• Voluntary

37. Patient force factors
A. Bruxism
B. Clenching
C. Tongue thrust
D. Crown height
E. Masticatory dynamics
F. The opposing arch

38. Bruxism

52. Clenching

62. Tongue thrust

64. 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

67. Masticatory dynamics
• Old vs. young
• Female vs. male
• Large built vs. small built
• Normal occlusion vs. parafunctional
• Neuromuscular disturbance

71. The opposing arch
Removable partial
denture
Fixed partial denture
Natural teeth
Implant

73. Bone density

74. 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

75. Etiology of variable bone density
• Do you remember Wolff ?
• The mandible Vs. maxilla
• Bone density location

79. Misch bone density classification

91. Radiographic bone density

100. Key implant positions and number

101. 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

111. 4 golden laws of multiple implant
placement
1 •No cantilever
2 •No three adjacent pontics
3 •Canine molar rule
4 •Arch dynamics

112. No cantilever

117. No three adjacent pontics

122. Canine molar rule

129. Implant size

130. Forces applied to dental implant
shear
tension
compression

131. force
duration
magnification
direction
type

132. Length
width
Implant
surface
area

133. Long
implants
Short
implants

134. • 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

135. • Implant size manipulation
Increase the diameter
Splint together
Decrease crown height
Increase implant surface area
OD VS FPD
Minimize lateral forces
Improve bone density

136. Implant diameter
Narrow Wide

137. • 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

138. • Disadvantages of wide implants
Bone trauma
Decreased facial bone thickness
Stress shielding
Increased surgical failure
Damage to the adjacent tooth

139. • 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

141. Available bone

144. • 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

146. • 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.

147. • 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.

154. • 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.

156. Treatment options :
(1) Osteoplasty
(2) Root form implants
(3) Subperiosteal implants
(4) Augmentation procedures
(5) Ramus frame implants
(6) Transosteal implants

157. Division D (Deficient Bone)
• Severe atrophy
• Basal bone loss
• Flat maxilla
• Pencil thin mandible

160. 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 .

161. Implant design