Misfit profile of dental bridges.

Clinical evidence has shown that dental bridge (DB) misfit is more frequent than individual crown restoration misfit, and that it causes restorative failures. A comparative study of misfit profiles was performed for the most common clinical situations in mouth rehabilitation procedures with fixed restorations: gold-cast DB and porcelain metal alloy DB. Evidence from this study may lead dentists to consider the advantages and weaknesses of one structure type over the other. The results obtained showed two different profiles, with the porcelain metal alloy (PMA) DB being less predictable than the gold-cast DB. The posterior abutment restoration tends to come apart distally from the tooth structure and get closer to the mesial aspect, while keeping distal-medial separation with respect to the anterior abutment. The gold-cast DBs showed a separation pattern in which the distal end comes away from the molar and the medial end from the premolar, getting clearly closer to the faces next to the pontic: its distal aspect gets closer to the premolar and mesially to the molar The study has also shown that even though the adaptive patterns are different, is less in PMA than in gold alloys, the latter being used only in a small percentage of clinical indications in oral rehabilitation, mainly due to aesthetic demands and high costs. The impact of this research in clinical dentistry is that PMA DBs have shown worst marginal adaptation areas where clinically, there is lack of vision or inaccessibility for appropriate dental preparation.