Ideal Occlusion
The optimal occlusion for implant-retained single crowns or fixed bridges should include the following characteristics, as supported by evidence from Davies (2010), Kim et al. (2005), and Sheridan et al. (2016):
- Cusp-to-Fossa Relationship: The occlusion should promote a cusp-to-fossa contact pattern, ensuring that the forces are directed along the long axis of the implant, which helps in distributing occlusal forces more evenly and reduces the risk of lateral loading.
- Narrow Occlusal Table: A narrower occlusal table is recommended to minimise the lateral forces on the implant, thereby reducing the stress on the implant components and surrounding bone. This design also helps to lower the risk of implant complications.
- Axial Loading Only: Occlusal forces should be directed axially, or along the long axis of the implant, to enhance the stability of the implant and reduce the risk of biomechanical complications, such as screw loosening or implant fracture.
- Light Occlusal Contacts: Posterior implant-supported crowns should have lighter occlusal contacts compared to natural teeth. Specifically, the occlusal contact on an implant crown should be approximately 30 μm lighter than on adjacent natural teeth. As a practical reference, a shimstock, which is 10 μm thick, can be used to measure and verify these contacts.
- Minimal or No Contact During Mandibular Excursions: The implant restoration should have minimal or no occlusal contact during lateral and protrusive mandibular movements. This reduces the lateral forces applied to the implant, which are more likely to cause mechanical complications and peri-implant bone loss.
- No Guidance on Implants: Implant restorations should not provide guidance during occlusal movements. Instead, it is preferable to have canine guidance on the natural teeth or a group function occlusal scheme. This approach helps to protect the implant from excessive lateral forces and ensures the natural dentition takes on the majority of the functional load during excursions.
These occlusal principles are designed to optimise the longevity and function of implant-retained prostheses by minimizing stress on the implant components and surrounding structures.
We would like to acknowledge Dr. Manraj Kalsi for his insights and contributions to this page