Dimensions of metal framework components of metal-ceramic fixed partial dentures constructed in a dental school setting

Objectives: The aims of this study were to measure the dimensions of connectors and retainer copings of metal-ceramic fixed partial denture (FPD) frameworks and to explore, by means of a questionnaire, the factors viewed by technicians as important in their planning and provision of such dimensions. Method and materials: Using two calliper devices, measurements were made of 66 consecutive FPDs under production in a dental school-based laboratory. The dimensions of 176 connectors and 124 retainers were analyzed with reference to FPD length and to number of pontics in a span. Questionnaires were completed by all 14 technicians working in the fixed prosthodontics section of the laboratory. Results: The largest mean vertical connector dimensions were in the anterior regions of both arches, while the largest mean horizontal dimensions were in the posterior regions. Dimensions were unrelated to FPD size and length of interabutment span. The minimum thickness of the retainer coping walls was generally below optimal recommendations. Available space was the factor most commonly cited by technicians as dictating the dimensions that they applied. Conclusion: Dimensions were generally smaller than current recommendations, which the questionnaire responses indicate are largely due to space constraints.