IMPLANT BIOMECHANICS

- Dr. Hemal Patel

OSSEOINTEGRATION

• Occurs when an implant is inserted into living bone• Connection/bond between living bone and implant

• Key for long term stability

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 TorqueConstants Bone and perioral tissues

FORCE

- At rest- In function- Parafunction

- Compressive- Tensile- Shear

Force magnitude, direction, duration, magnification

Three moment arms in implant dentistry:Occlusal height: Div A < Div C, DOcclusal 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

Quality: D1, D2, D3, D4

Quantity: A B B-w C-w C-h D

BONE

IMPLANT1. Biomaterial: Ti alloy2. 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 al3. Placement and Prosthetic restoration

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)

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

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

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

THANK YOU