Long-term analysis of biologic and technical aspects of fixed partial dentures with cantilevers

The aim of the present clinical study was to analyze the long-term treatment outcome of fixed partial dentures (FPD) with cantilevers.

Ninety-two patients with 115 cantilever FPDs on 239 abutment teeth were examined. Immediately following cementation, radiographs of the abutment teeth were obtained. At the follow-up examination 5 to 16 years after cementation, the abutment teeth were clinically and radiographically evaluated. Besides the assessment of periodontal parameters and vitality testing, the presence of carious lesions of the abutment teeth, loss of retention, fracture of bridgework, and fracture of abutment teeth were also recorded. The Student's t test was used to detect differences between abutment teeth and control teeth with natural crowns as well as over time within the groups.

Plaque scores and bleeding on probing were low at both abutment and nonabutment teeth. Mean probing pocket depth and level of the clinical attachment never exceeded 3.0 mm in both groups. The radiographic bone levels at abutments were stable within 3% over the observation period. Of the 120 initially vital abutment teeth, 12 (10%) lost vitality during the observation period; one (1%) of the 119 initially nonvital abutments showed periapical pathology. Development of secondary caries was observed at 8% of the 239 abutment teeth. In total, 8% of the abutment teeth were affected by loss of retention, which made up more than half of all technical problems. Material fractures only occurred occasionally, affecting from 1% to less than 3% of the abutment teeth. Fracture of abutment teeth amounted to 3% and was twice as frequent at abutments adjacent to cantilevers compared to abutments not adjacent to cantilevers.

The most frequent biologic (caries) and technical complications (loss of retention) made up more than half of all problems recorded. These problems may be at least partially avoided by performing optimal plaque control and by strictly observing the rules for preparation of retentive FPD abutments.