The bases for using a particular occlusal design in tooth and implant-borne reconstructions and complete dentures.

OBJECTIVES

A systematic review identified randomised and other trials (1966-2006) of studies of occlusal design of crowns, complete (CRP) and partial (PRP) removable prostheses and implant-borne reconstructions, and whether occlusal design influenced diet, quality of life, bruxism and attrition.

METHODS

The search primarily included Cochrane Database of Systematic Reviews and Central Register of Controlled Trials, Database of Abstracts of Reviews of Effectiveness, Ovid Medline and PreMedline.

RESULTS

The search yielded 1315 studies: 20 on CRP--1 RCT, one systematic review, four clinical trials, 10 case series; 22 on PRP - one cohort study, two experimental studies, 15 case reports or case series, three clinical trials; 23 on implant superstructures, and 24 reports on implant failure, 37 on oral health related quality of life, eight on attrition; and four studies on masticatory function.

CONCLUSIONS

CRP--Studies of occlusal form and tooth arrangements, included balanced, lingualised and monoplane arrangements--lingualised posterior occlusion was preferred. Early studies on CRP design were observational as case reports, however data suggested that optimum function is achieved by modification of the maxillary occlusion, irrespective of the opposing mandibular occlusion. PRP--Edentulous ridge resorption is patient-specific, has a multifactorial aetiology and there is no objective data to confirm that mechanical factors cause bone loss; oral hygiene management is crucial for long-term health. Studies on distal extension PDs confirmed a link between bite force and masticatory function; preservation of two functioning posterior tooth units ipsilateral to the distal extension optimises function. Data indicate that patient-specific factors, rather than PD design-specific features, influence long-term PD outcomes. Implant superstructures--There is little scientific evidence specifying occlusal and superstructure design for fixed prostheses for teeth or implants. Occlusal scheme design and occlusal form have evolved through clinical experience, but there is no evidence to indicate that a particular design is superior. Complex neurophysiological mechanisms allow the jaw muscle system to accommodate to oral and dental changes.