Reorientation simplified: A device for recording and reproducing the path of insertion for removable partial dentures.

Aim: The record of path of insertion on the dental cast is part of the dentist's work authorization to the dental laboratory technician. The path of insertion record enables the dental technician to replace the cast on a surveyor in the same position that the dentist selected. Analysis of factors that influence the path of insertion should determine a path of insertion that will reduce the potential for dislodgement and promote stability of removable partial denture (RPD). Materials and Methods: The recording of the relation of a cast to a dental surveyor and the transfer of this relationship to the dental laboratory may be done by tripodization, by scoring the base of the cast, or by cementing a reference pin on the cast. Conclusion: Recording the established path of insertion can be difficult when the procedure uses a cemented pin and the casts are mounted in an articulator. This article describes a procedure for innovative dowel pin and sleeve device to record the path of insertion of RPDs, which serves the same purpose as the cemented pin but can be easily removed and replaced.

In vitro comparative evaluation of the effect of two different fiber reinforcements on the fracture toughness of provisional restorative resins.

Background: Fracture of provisional fixed partial denture (FPD) may jeopardize the success of provisional prosthodontic treatment phase and cause patient discomfort. Aim: The aim of this study was to compare the fracture toughness of the Polymethyl Methacrylate (PMMA) resin and Bis-Acryl Composite (BAC) resin reinforced with the Polyethylene and Glass fibers. Materials and Methods: Three groups (N=10) of each of the two materials were prepared for the fracture toughness test. Two groups had the different reinforcements and group without reinforcement served as the control. The mean fracture toughness (MPa.m½ ) was compared by One-way ANOVA, followed by the Scheffe analysis. Fracture toughness between fiber-reinforced PMMA and BAC resin was compared by the independent samples t test. Results: For the controls, the fracture toughness for PMMA resin (0.91) was significantly lower than for the BAC resin (1.19). Glass fiber reinforcement produced significantly higher fracture toughness for both, PMMA (1.48) and BAC (1.82) resin, but the Polyethylene fibers did not (0.95 for PMMA and 1.23 for BAC resin). Among the reinforced groups, Silane impregnated Glass fibers showed highest fracture toughness for the BAC resin (1.82). Conclusion: Of two fiber reinforcement methods evaluated, Glass fiber reinforcement for the PMMA and BAC resin produced highest fracture toughness. Clinical Implications: On the basis of this in--vitro study, the use of Glass and Polyethylene fibers tested may be an effective way to reinforce resins used to fabricate fixed provisional restorations.