Background and Objectives: Accurate impression taking is a prerequisite for achieving passive fit between the implant and superstructure. This study sought to assess the accuracy of impressions taken from 15° and 25° angulated implants by two plastic and metal stock trays using the splinted open tray technique. Materials and Methods: This in vitro experimental study was conducted on 20 gypsum casts. An acrylic model was fabricated with a first premolar to first premolar edentulous area and second premolar and first, second and third molar teeth present in both sides. Two implants were placed vertically at the site of lateral incisors. At the site of first premolars, one implant with 15° angulation and another one with 25° angulation relative to the midline were inserted. Ten plastic and 10 metal stock trays were used for open tray impression taking with addition silicon impression material at the site of copings. Casts were poured and coded. Measurements were made using coordinate measuring machine (CMM). The data were analyzed using t-test (for normally distributed data) and non-parametric tests (for non-normally distributed data).Results: The A1 distance was 7.253±0.053mm in plastic and 7.249±0.42mm in metal tray group. These values were 9.807±0.026mm and 9.802±0.009mm, respectively for A2, 34.483±0.132 and 34.462±0.112, respectively for A3, 28.210±0.1332 and 28.193±0.011, respectively for A4 and 52.709±0.032 and 52.717±0.041, respectively for A5. These differences were not statistically significant (P>0.05). Conclusion:Both plastic and metal stock trays are accurate for position transfer of parallel and angulated implants in splinted open tray technique.

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Background and aim: Oral microbiota could proliferate the microspace between the implant and abutment, thereby cause inflammation in the peri-implant tissues and adjacent bone. This study aimed to investigate the effect of two types of abutments (zirconia and titanium) on microleakage at implant-abutment interface area under oblique cyclic loading in vitro. Materials and methods:In this in vitro study, 12 implant-abutment assemblies were used, each containing six sets with either zirconia or titanium abutments and vertically mounted in the modified resin blocks of autopolymerized polyester base. The specimens were then subjected to oblique cyclic loading of 75 N at a 30 ± 2 degrees angle to the longitudinal axis of the implant with a frequency of 1 Hz in 500,000 cycles, equivalent to 20 months of human mastication. To determine the penetration of fuchsine into the implant-abutment interface, the implants were cut by cutting machine from the middle. Then, the rate of penetration of fuchsine in each sample was measured by a stereomicroscope with a magnification of 75 × at three points of each semicircle, and the average of these six points was recorded as a microleakage. For comparison of the microleakage after loading, t test was used. All tests were performed in SPSS ver.22 software and a significant level of 0.05 was considered. Results:The amount of microleakage after oblique cyclic loadingwas statistically significantly higher in the zirconia abutments (66.08±11.66) compared to the titanium abutments (39.17±10.65)following force application (P = 0.002). Conclusion:The microleakage following oblique cyclic loading is different depending on the type of abutment, so that the titanium abutments showed significantly less microleakage than the zirconia abutments.