Periodontal effects of fixed partial denture retainer margins: Configuration and location

Our purpose was to study the periodontal response to posterior fixed partial denture (FPD) retainers with different marginal configurations and locations. One posterior proximal site restored with a clinically acceptable FPD and one matched, unrestored posterior proximal site were examined in 60 subjects. Assessments were made of the FPD retainers and the periodontal responses to both the long-term and short-term use of these retainers. Periodontal examination included assessment of probing depth and bleeding on probing and determination of plaque index and the gingival index scores. Statistical analysis showed that "clinically acceptable" FPDs, which had clinically detectable deviations from an ideal (flat) retainer/tooth configuration, were not associated with increased probing depth or bleeding on probing when compared to the matched, unrestored teeth at both examinations. As a group, sites adjacent to subgingival retainer margins were not associated with greater probing depths than sites adjacent to supragingival retainer margins. These findings suggest that long-term exposure to variations of FPD margin configuration and location, within clinically acceptable but less than ideal parameters, are not associated with the destruction of the supporting periodontal tissues.