ObjectiveThis study determined the effects of various surface treatment modalities on the bond strength of composite resins to glass-ionomer cements. Material and MethodsConventional (KetacTM Molar Quick ApplicapTM) or resin-modified (PhotacTM Fil Quick AplicapTM) glass-ionomer cements were prepared. Two-step etch-rinse & bond adhesive (AdperTM Single Bond 2) or single-step self-etching adhesive (AdperTM PromptTM L-PopTM) was applied to the set cements. In the etch-rinse & bond group, the sample surfaces were pre-treated as follows: (1) no etching, (2) 15 s of etching with 35% phosphoric acid, (3) 30 s of etching, and (4) 60 s of etching. Following the placement of the composite resin (FiltekTM Z250), the bond strength was measured in a universal testing machine and the data obtained were analyzed with the two-way analysis of variance (ANOVA) followed by the Tukey's HSD post hoc analysis (p=0.05). Then, the fractured surfaces were examined by scanning electron microscopy. ResultsThe bond strength of the composite resin to the conventional glass-ionomer cement was significantly lower than that to the resin-modified glass-ionomer cement (p<0.001). No significant differences were determined between the self-etching and etch-rinse & bond adhesives at any etching time (p>0.05). However, a greater bond strength was obtained with 30 s of phosphoric acid application. ConclusionsThe resin-modified glass-ionomer cement improved the bond strength of the composite resin to the glass-ionomer cement. Both etch-rinse & bond and self-etching adhesives may be used effectively in the lamination of glass-ionomer cements. However, an etching time of at least 30 s appears to be optimal.

This report describes a case of immediate hypersensitivity reaction associated with the mercury component of amalgam restorations. The release of mercury induced an acute reaction which resulted in erythematous lesions, severe burning and itchy sensation and diffi culty in breathing. Skin patch test results indicated a very strong positive reaction to mercury. Amalgam restorations were replaced with composite fi lling material. The patient, her family and her dental practitioner were strictly advised to use alternative restorative materials in case of a need for restoration.

Developments in nuclear technology in the last century have lead to the use of radiation in different areas of human activity. These are not just the energetics but also food, agriculture, medicine, industry and science. Thus, radiation has become an inevitable phenomenon in our lives. Since we cannot isolate radiation from our life, the radiation protection methods should be available. As alternatives to conventional radiation prevention methods, such as lead and heavy concrete shielding, more functional materials need to become the focus of research. The development of the least harmful to the environment, easily applicable, flexible radiation shields has become very important. In this study, silicon matrix composite panels, doped with different ratios of barite and boron carbide, were produced and characterized by optical and scanning electron microscopy (SEM). Gamma and neutron radiation shielding properties of these materials were investigated. The results have been compared with the lead as the standard shielding material.