Background: The most important factor in fabrication of a perfect crown is having a perfect margin, which matches completely with finish line preparation and has a good situation in relation to the alveolar bone crest. To control the quality of the fixed prostheses made in a dental clinic in Shiraz, there was an attempt to assess the quality of their margins. Materials and Method: Radiography was used to check this quality. Parallel periapical radiography was made from the 102 crowns and bridges after cementation and before discharging the patients. To measure the magnification, a metal ball with 4mm diameter was attached on the crowns at the line of their proximal margins before taking images. To obtain more exact and detailed information, a projector was used to increase the magnification of the images. The distance between the crown's margin and finish line in horizontal and vertical aspects and also the distance to the alveolar bone crest were measured.Results: The statistical analysis of the data revealed that in 76.5 percent of the cases the crowns had more gap in the vertical aspect than the acceptable range (50 micro meters). In 60.8 percent of the cases there was a gap in the horizontal aspect. In 11 percent of the cases, a ledge was seen in the horizontal aspect and by combining the gaps in both horizontal and vertical aspects, it was seen that, as a whole, 92.2 percent of the crowns had more gaps than the acceptable range. Also it was seen that in 77 percent of the cases in the mesial and 64.5 percent in the distal part, the crown's margin had invaded to the biologic width.Conclusion: It is concluded that it would be worthwhile to make radiographic image to check the framework, thereby important errors, which are difficult or impossible to discover by clinical examination will be shown.

Introduction: This in vitro study investigates the MARGINAL and internal FIT of indirect class II composite restorations. Two different processes for chair-side restorations were compared. In group A, the restorations were fabricated using CAD/CAM technology (Cerec, Sirona, Germany, Bernsheim) and in group B they were made by hand (GrandioSO Inlay System, VOCO GmbH, Germany, Cuxhaven).Methods: For a metal tooth with a MOD cavity each 10 restorations were made for groups A and B. For each restoration, a replica of the cement-gap made from light body silicone was produced by placing the restoration into the cavity of the metal tooth. For this purpose, a special restoration-positioning machine was developed. Each replica was sectioned off in the longitudinal axis (L) and in the cross axis (C). The thickness of the replicas was measured in both directions, using picture analysis software under a light reflection microscope. To evaluate the FIT of the restorations, a special FITting parameter was calculated. Statistical analysis was performed with the t test.Results: The FITting-parameter in group B (L: 97.6mm±73.0mm; C: 71.8mm±46.4mm) was significantly lower than that of group A (L: 155.1mm±102.3.0mm; C: 168.2mm±91.9mm) (P<0.001).Conclusions: Within the limitations of this in-vitro study hand-made composite restorations using the GrandioSO Inlay System seems to be a good alternative to CAD/CAM production. The clinical success of these restorations has to be evaluated in further studies.

Background and Aim: An important criterion for success assessment of implant-supported prostheses is MARGINAL FIT. Vertical and horizontal discrepancy can result in loosening of the prosthetic screw, crestal bone resorption, peri-implantitis and loss of osseointegration. Despite careful attention to waxing, investing, and casting, MARGINAL discrepancies are inevitable. The aim of this study was to evaluate the MARGINAL gap and overhang in three casting methods with two different alloys in ITI implants.Materials and Methods: In this experimental in vitro study 48 analog abutments were randomly divided into six groups as follows: 1) burn out cap + BegoStar, 2) impression cap + BegoStar, 3) conventional wax up + BegoStar, 4) burn out cap + Verabond2, 5) impression cap + Verabond2, 6) conventional wax up + Verabond2. Waxing was done in 0.7 mm thickness verified by a digital gauge and a putty index was made for all groups. Reamer was used for correction of the finish line after casting in all groups. Castings were seated on analog abutments and embedded in acrylic resin. Specimens were sectioned by isomet instrument and polished and cleaned by ultrasonic cleaner for 10 min. The MARGINAL gap and overextended margins of castings were examined under a Scanning Electron Microscope (SEM) (X200). The mean gap and margin overextension were calculated for each group. Data were analyzed by multivariate analysis and Bonferroni post-hoc test with p<0.05 as the level of significance.Results: No significant difference in gap size was observed among the three casting methods with two alloys (P=0.056). The MARGINAL gap was not different in the studied casting methods (P=0.092). Gold alloy crowns showed lower MARGINAL gaps compared to base metal alloy crowns (P<0.001). No significant difference in overhang size was observed among casting methods with two alloys (P=0.093). Base metal alloy crowns showed less overhang compared to gold alloy crowns (P<0.001). There was a significant correlation between overhang and use of impression cap in base metal alloys (P<0.001).Conclusion: Based on the results of this study, vertical discrepancy of frameworks made with gold alloy were less than those made with base metal alloy. Base metal alloy demonstrated fewer overhangs. Conventional wax up or using burn out caps produced less horizontal discrepancy.