A comparative evaluation of properties of zirconia reinforced high impact acrylic resin with that of high impact acrylic resin

AbstractStatement of the problemPoly methyl methacrylate (PMMA) acrylic resin, although being the most popular denture base material, is associated with poor mechanical properties. It has been documented that acrylic resin can be strengthened with an addition of structural component (filler) added in the acrylic matrix, to form a composite structure.ObjectiveTo evaluate and compare the transverse strength, impact strength, surface hardness and water sorption of 10% and 20% zirconia (ZrO2) reinforced high impact acrylic resin with that of high impact acrylic resin (Trevalon HI, Dentsply India).Materials and methodsThere were 30 specimens in each of the four tests, amounting to a total of 120 specimens. Each of the tests had 10 specimens fabricated from high impact acrylic resin (control); 10 specimens fabricated from 10% zirconia (ZrO2) and 10 specimens fabricated from 20% zirconia (ZrO2) reinforced high impact acrylic resin. Specimens were subjected to the test of transverse strength in Universal Testing Machine, impact strength in Izod pendulum impact testing machine and surface hardness by Vickers Microhardness tester according to ISO Specification No. 1567. Water sorption was assessed according to ADA Specification No. 12. Data were analyzed by means of a one-way ANOVA and Bonferroni multiple comparison test.ResultsA significant increase in the transverse strength was observed in the reinforced specimens when compared to the control group. Impact strength and surface hardness were found having lesser values compared to the control group. Water sorption was found to increase on the addition of 10% and 20% zirconia (ZrO2) but the value lied below 0.8mg/cm2 i.e. within the limit of ADA Specification No. 12.ConclusionReinforcement of acrylic resin with zirconia powder affects its physical and mechanical properties significantly

Assessment of salivary titanium levels among patients undergoing dental implants: A case control study

Background: Dentistry is a continually evolving branch of medicine that is significantly affected by technological developments. The goal of modern implant dentistry is to restore physiological function, comfort, aesthetics, speech, and health to individuals who have missing teeth. The present study was conducted for assessing the salivary titanium levels among patients undergoing dental implants. Materials & methods: A total of 30 patients who underwent dental implant therapy were enrolled in the present study. Complete clinical and demographic details of all the patients were obtained. Another set of 30 healthy subjects were enrolled as control group. All the patients underwent dental implant procedures under the hands skilled and experienced implantologists. Postoperatively after one month, salivary samples were obtained from all the patients of the dental implant group and salivary titanium levels were evaluated. Salivary samples were also obtained from the control group subjects and salivary titanium levels were evaluated and compared. Results: The mean concentration of salivary Titanium among subjects of dental implant group and control group was 158.2 μg/L and 239.8 μg/L respectively. Significant results were obtained while comparing the salivary titanium levels among the subjects of the study group and control group.&nbsp

Analysis of accuracy of two different implant impression techniques: A comparative study

Background: Comparatively evaluate the accuracy of two different implant impression techniques. Materials & methods: For the present study, reference models used were an edentulous mandibular cast with four implant analogues in the anterior region and a metallic insert in the posterior. Two impression techniques were studied as followed: Group 1: Polyvinyl siloxane impressions (putty and light body) using stock metal tray, and Group 2: Polyether impressions (medium body) using stock metal tray. Connection of the impression posts was done to implant analogues with the screws tightened manually such that their flat surfaces were facing buccally. The longer impression posts were connected to the anterior analogues and shorter were connected to the posterior analogues. A self-calibration test was performed to determine the accuracy obtained by the single evaluator. Results: Mean error among the specimens of Group 1 was 0.0441 while mean error among the specimens of Group 2 was 0.0425 respectively. While comparing the mean error among the two study groups, non-significant results were obtained. Conclusion: From the above results, the authors concluded that both the impression techniques can be used with equal effectiveness in implant procedures.&nbsp