Purpose: The purpose of this paper is to investigate the influence of interphase properties on restored tooth structure due to polymerization shrinkage of resin-based composite.
Materials and Methods: A 3D finite element analysis was performed. The restoration-tooth interface was simulated using solid elements of varying material properties and thicknesses. The stress within the restored tooth structure built up from the polymerization shrinkage of the restorative composite was computed accounting for the time-dependent and visco-elastic behavior of the composite.
Results: It was found that a correlation exists between material and geometry properties at the restoration-tooth interface and higher shrinkage stresses were located at the interphase due to polymerization shrinkage. The development trend of residual stress from polymerization shrinkage in the restored-tooth structure was predicted.
Conclusion: The varying material and geometry properties of restoration-tooth interface seemed to have a conclusive effect on the interfacial stress system, as well as on the longevity of the restoration. From the purely mechanical point of view, this can result in interfacial debonding.

Purpose: The brush-on technique was developed to compensate for polymerization shrinkage. In this study, we assess the dimensional accuracy of autopolymerized resin applied using a brush-on technique.
Materials and Methods: Each of five autopolymerized resins, Unifast II (GC), Unifast Trad (GC), Provinice (Shofu), Metafast (Sun Medical), and Miky (Nissin), was applied three times inside a ceramic cylinder (10 mm internal diameter; 5 mm width) using a brush-on technique (horsehair resin brush, Seiundo). As controls, the five resins were applied inside cylinders after the polymer and monomer were mixed at 0.5 mL/g for 10 s. After polymerization, the cylinders were cut into 3-mm wide pieces using a precision cutting machine. The maximum gaps between the ceramics and resins were measured using a scanning electron microscope at a magnification of x500. The dimensional accuracy (n=5) was assessed as the shrinkage percentage (the gaps divided by the internal diameter of the tubes). The data were analyzed by ANOVA/Tukey’s test (α=0.05).
Results: Excluding Metafast, the brush-on technique differed significantly from the controls (p<0.05). Using the brush-on technique, Metafast had the greatest shrinkage, and Unifast had the lowest shrinkage. However, there was no significant difference among all the resins tested (p>0.05).
Conclusion: The dimensional accuracy of the autopolymerized resin using the brush-on technique was better than that of the conventionally mixed polymer and monomer because the polymer and monomer ratio using the brush-on technique was lower and polymerization shrinkage was minimized due to the brush-on technique.

This article reports a resin-bonded fixed partial denture (RB-FPD) applied to a diabetic. Before seating the RB-FPD, a removable partial denture was used for about one year after extraction of a second molar. The RB-FPD framework was cast from silver-palladium-copper-gold alloy (Castwell M.C. 12), and the surface to be bonded was air-abraded with alumina. The RB-FPD was then treated with a metal priming agent (V-Primer), and bonded with an adhesive resin (Super Bond Opaque). After an observation period of six years and six months, the FPD was functioning satisfactorily. The materials and procedures reported here are applicable as an option for a prosthodontic treatment for medically compromised patients.