Much of the information for occlusal schemes on dental implant protheses is derived from occlusal concepts from NON-implant (tooth-supported) prostheses. Various publications have found insufficient evidence to establish firm clinical guidelines for preferred occlusal schemes on implant prostheses. To compound the difficulty, there remains a difference of published opinion as to what occurs ‘naturally’ in the human dentition. There is some evidence from a systematic review that, with ageing, the prevalence (in the natural dentition) of a cuspid-guided occlusion decreases, with an increase in the prevalence of a group-function occlusion.

General published reviews have incorporated clinical guidelines as axioms, paradigms, concepts and correct practice that are highly practical but are, in many cases not evidence-based due to a lack of available evidence.

In creating a therapeutic occlusal scheme, mutual protection and anterior disclusion have come to be considered as acceptable modalities when restoring natural teeth. The aim being to restore and maintain function and minimize the interval for patient adaptation. The greater the therapeutic change to the occlusion, generally the greater the time for patient adaptation to occur. Any therapeutic change should provide biologic and mechanical stability over time.

These same concepts have been transferred to the restoration of implant-supported restoration largely by default.

So with these assumptions and poorly established data, I contribute my ‘expert opinion’ in the knowledge that this is the lowest level of scientific evidence. Below are the guidelines that I clinically adopt and specific to several different therapeutic modalities commonly encountered.

Implant-supported single crown (with natural teeth on both proximal sides)

• Establish a ‘home-base’ reference point on natural teeth that are on either side of the I-SC, using an 8-micron thickness articulating foil (‘Shimstock’)
• Test to light closure tooth contact – the I-SC should ‘release’ the shimstock
• Test to clench tooth contact – I-SC should then ‘hold’ the shimstock, as this allows for tooth movement provided by the resilience of the periodontal ligament around the teeth
• Immediate disclusion in an eccentric movement
• Specifically, in relation to a maxillary anterior I-SC, ensure there is sufficient palatal concavity to adequately allow for protrusive mandibular movements in speech and mastication. In the anterior mandible, avoid exclusive contact on the I-SC in protrusive incisal edge contact
• Posterior I-SC – in either jaw, design the internal triangular ridges on the occlusal surface to be slightly concave, as opposed to a little worn occlusal surface where the triangular ridges are usually convex from the cusp arm to the internal groove or fossa. This is particularly important in patients who demonstrate an immediate lateral condylar side-shift

Posterior I-FDP (in Kennedy Class I or II space) – with no natural tooth distal to the prosthesis:

• Establish a ‘home-base’ reference point (as described above)
• Test to light closure tooth contact – I-FDP ‘release’
• Test to clench tooth contact – I-FDP ‘hold’
• Eccentric movement disclusion
• Occlusal table – copy the general occlusal morphology that the patient has created over time – occlusal table should have triangular ridges flat or slightly concave

Anterior I-FDP (in Kennedy Class IV space):

• As described for the anterior I-SC, and;
• Develop concept of ‘mutual protection’

Complete arch I-FDP (or I-cFDP)

• This type of restoration dictates a fully therapeutic occlusal scheme
• Bilateral synchronous inter-arch contacts on closure of posterior teeth – one contact per tooth unit is adequate
• Lateral guidance based on principles of mutual protection
• A cuspid-guided occlusal (CGO) scheme can be considered simpler technically and mechanically
• Additionally, consider a shortened dental arch (SDA) design

Patients may have an initial decreased tactile perception with implants and therefore the potential for decreased ability to detect discrepancies in their implant occlusion compared to natural teeth. The perception appears to improve over time. Thus, ongoing reviews are very important. The greater the extent of the therapeutic intervention, the shorter should be the early review time interval. An I-SC should be reviewed at least annually for the first three to five years and at each review, the occlusal ‘evaluation’ outlined above is repeated and adjustments made where indicated.