In vitro repair of three-unit fiber-reinforced composite FPDs

Purpose: Clinical damage, such as the fracture or abrasion of composite ven eers, may cause the loss of a fixed partial denture (FPD). Intraoral method s may help in repairing and therefore lengthening the life span of the rest oration. The aim of this in vitro study was to evaluate an intraoral method of repairing fractured FPDs made of two different fiber-reinforced composi te framework systems. Materials and Methods: Shear bond strengths of a comp osite between two different fiber-reinforced composite frameworks were dete rmined after five different mechanical surface treatments. A silicate-silan e coating intraoral air-abrading system provided the most reliable bond str ength values and was therefore used for treatment for the following veneer repair. The repair of 24 three-unit posterior FPDs was performed using a re storative composite resin. All FPDs were examined after simulating clinical service using thermocycling and mechanical loading. Fracture forces were d etermined for original FPDs and for FPDs after simulated intraoral repair. Results: The fracture strength of all original FPDs was about 900 N. After repair, a maximum decrease in strength of about 15% was determined. FPDs th at were extremely damaged by cutting the framework showed the lowest result s, with values of about 450 N. Conclusion: The repair of the fractured vene er of fiber-reinforced composite FPDS provided good results and therefore m ay lengthen the life span of damaged FPDs. The repair of the fractured fram eworks showed good results but can only be recommended for limited temporar y use.