Implant Biomechanics
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This document discusses implant biomechanics and osseointegration. It notes that osseointegration occurs when an implant bonds to living bone, providing long term stability. Biomechanics involves the interaction between forces and tissues in the body. Key factors for implants include force magnitude and direction, as well as moment arms related to implant location and design. Proper implant selection, placement, and occlusion are important to minimize these forces and moments to prevent implant failure.
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Implant Biomechanics
- 1. IMPLANT BIOMECHANICS - Dr. Hemal Patel
- 3. OSSEOINTEGRATION •Occurs when an implant is inserted into living bone •Connection/bond between living bone and implant •Key for long term stability
- 4. Biomechanics is the interaction between the tissues and organs of the body and the forces acting on them. It is the response of the biologic tissue to the applied loads. Variables Force, Moment and Torque Constants Bone and perioral tissues FORCE - At rest - In function - Parafunction - Compressive - Tensile - Shear Force magnitude, direction, duration, magnification
- 5. Three moment arms in implant dentistry: Occlusal height: Div A < Div C, D Occlusal width: Large occlusal table increase the moment impact for any offset occlusal loads. Cantilever length: •Antero-Posterior (A-P) •Parafunction •Arch form Minimization of these arms are necessary to prevent any implant failure! Square Ovoid Tapered
- 6. Quality: D1, D2, D3, D4 Quantity: A B B-w C-w C-h D BONE
- 7. IMPLANT 1. Biomaterial: Ti alloy 2. Geometry: - Crest module - Shape: cylindrical, tapered, conical, hybrid et al - Size - Threads: Y/N? Thread geometry, pitch, depth et al - Surface treated: Plasma sprayed, HA coated et al 3. Placement and Prosthetic restoration
- 8. Implant placement Conventional placement guided by anatomy and surgical guide after treatment planning! Tilted implants
- 9. Platform switching: Use of a smaller-diameter abutment on a larger-diameter implant collar. Preserves crestal bone level Provides horizontal component to biologic width; Implant-abutment interface is shifted inwards Inflammatory cell infiltrate in non-platform switched (L) & platform-switched implant (R) 9
- 11. Biomechanical case planning •Force magnitude, direction, duration type and magnification •Site: Location, bone, bony undercut •Type, height, size (length+diameter), functional surface area of implant •Surgery
- 12. To summarize, •Case based Implant selection: variables – number, shape, threads, pitch, surface, length, diameter, et al. •Elimination of parafunction •DON’T connect implant to natural tooth! •DON’T use wide diameter implants in very dense bone! •Proper occlusion and loading: - Implant protected occlusion - Progressive loading - Cross bite for buccally resorbed • Maxillary anterior: Angled > Straight abutment Steep anterior guidance
- 13. Implant-protected occlusion: - increase the surface area of implants - decreasing the width of the occlusal table - reducing the occlusal contacts/no premature contacts, reduced cusp inclination, shallow occlusal anatomy, and wide grooves and fossae - improving the force direction - reducing the magnification of the force Progressive loading: • D1, D2, D3, D4 : 3, 4, 5, 6 months • Soft diet • Change of occlusal material: No contact acrylic final metal/ceramic Lateral load
- 14. THANK YOU
Notes de l'éditeur
- PDL: stress absorber, even force transmitter. Lateral F Alveolar crest/Horizontal/Oblique/Periapical/Interradicular fibers. Implant is fixed to the bone, there is osseointegration with bone. Lateral F @ crest. So placement, angulation and prosthesis delivery matter! Stress concentration on crestal bone so bone loss so
- Depends on: Material Surface Heat during surgery Initial stability Bone quality
- Force: At rest, perioral forces by tongue and cheek + in function: occlusal loads, mastication, et al Parafunction: bruxism, clenching, et al Moment: quantity of motion, tend to cause screw loosening, component fracture, bone resorption, interface breakdown Torque: force that causes rotation Compressive: pushing forces. cortical bone is strongest in compression; this force is accommodated best, by cement, screws, implant components, bone-implant interface. This is the force we want in implant. Tensile: pulling forces. Shear: sliding forces. other planar forces and we dont want these type of forces! Force magnifiers : 1. Cantilever length 2. Crown height 3. Night guards 4. Occlusal material 5. Over dentures
- Occlusal height and width are variable constants, variable because they can be modified by grafting within feasiblity AND constant , because there’s a limit to it, and after bone site healing, the final crown height and width will depend on the occlusion and available MD and BL distance. Div A less moment cos less crown height wrt C + D Occlusal width Narrow table with more centric points If large, then cantilever > moment & more occlusal force imparted cantilever length: 1. Antero-Posterior (A-P) spread, if more, then forces due to cantilever is better absorbed 2. Distal cantilever >/ 2.5 A-P spread 3. Contraindication: Parafunction 4. Square arch, less AP spread so less cantilever wrt tapered arch
- Bone is a constant, but it can be varied to limits with grafting and similar procedures. Now, according to the implant site features like bone, adjacent and opposite teeth et al; we have to place the implant. Conventional placement is not always feasible, sometimes modification in planning and procedure is mandatory.
- Ti alloys exhibits a higher endurance limit compared with commercially pure titanium Crest module: slightly larger diameter than implant, polished, not very long Cylindrical implant shear forces Long implant in D2/3 no, surgical risk cos engage opposite cortical & nerve repositioning/sinus grafting
- Palatal and lingual
- So if possible, abutment should be selected of smaller diameter than that of implant collar. If normal size abutments are to be used, then implant size has to be larger which is not poss uif bone width is less. If normal implant size used, then abutment will have to be smaller compromising emergence and esthetics in anterior cases.
- Dental implants function to transfer load to surrounding biological tissues. Thus the primary functional design objective is to manage (dissipate and distribute) biomechanical loads to optimize the implant supported prosthesis function. Definition: Process of analysis and determination of loading and deformation of bone in a biological system.
- If less dense bone, then pitch between threads should be more Force magnifiers : 1. Cantilever length 2. Crown height 3. Night guards 4. Occlusal material 5. Over dentures
- Square<3 X more shear component- v shape and buttress Thread pitch: smaller the pitch (finer) the more threads on the implant body for a given unit length, and thus the greater surface area per unit length of the implant body Cylindrical implant shear forces Long implant in D2/3 no, surgical risk cos engage opposite cortical & nerve repositioning/sinus grafting
- Occlusal table – axial loading