ABSTRACT
Dental composites are showing versatility in the field of restorative dentistry. Strength is main issue for their use especially in stress bearing area. Present study was aimed to evaluate the flexural strength of dental amalgam incorporated nano filled hybrid composite. Mechanical incorporation of a commercially available dental amalgam powder in nano filled hybrid composite was performed through amalgamator. Specimens were prepared and analyzed according to ISO standard No. 4049. Specimens analyzed were six [n=3] for each group. Null hypothesis for the study was no difference in the flexural strength of a commercially available dental composite and the prepared one which was rejected by the test statistics. Flexural strength of the control material was 90 Mpa while for the test material was 106.12 Mpa. Results showed a marked difference in the values of flexural strength of both the materials. Flexural strength can be increased by incorporating dental amalgam powder. Dental amalgam powder is a potential candidate for a high flexural strength and antibacterial composite. The study needs more trials on different aspects and evaluation of mechanical properties
ABSTRACT
Dental impressions are often neglected in clinical practice as a source of spread of infectious diseases. In Pakistan more than fifty percent of the clinicians do not disinfect impressions. Blood and saliva contaminated impressions should be either disinfected or sterilized before further handling. Aim of this study was to determine effect of autoclave sterilization on the time dependent dimensional stability of vinylsiloxanether impression material. Impressions of stainless steel die [ADA/ANSI specification No. 19], were made of Vinylsiloxanether. Out of 40 specimens, half were allotted to group A and were autoclaved at 134°C AND 20 psi for 5 minutes. Rest of the specimens [Group B] served as a control. Dimensional changes were calculated for two time intervals i.e. after one hour and after twenty-four hours. Samples were scanned and images were analyzed by using Adobe reader XI [AcroRd 32] software. Paired t-test showed significant difference [p = 0.007] between readings at first hour [-0.047%] and twenty fourth hour [0.084%] in group A. Whereas independent t-test showed no significant difference in group A and B for both time intervals i.e. at first hour [p = 0.162] and twenty fourth hour [p = 0.148]. It was concluded that Vinylsiloxanether can be sterilized in an autoclave without any deleterious change in dimensions