Background. This study aimed to assessthe antimicrobial effect of chlorhexidine (CHX) on Aggregatibacter actinomycetemcomitans biofilms isolated from subgingival plaque of peri-implantitis lesions.Methods. Thirteen patients requiring peri-implantitis treatment were consecutively selected and their subgingival biofilm was collected by inserting fine sterile paper points into peri-implant pockets for 15 seconds. A. actinomycetemcomitans was isolated from the subgingival biofilm and cultured. In this study, the standard strain of A. actinomycetemcomitans served as the positive control group and a blank disc impregnated with water served as the negative control; 0.1 mL of the bacterial suspension was cultured on specific culture medium and blank discs (6 mm in diameter) impregnated with 0.2%CHX mouthrinse (Behsa Pharmaceutical Co.) and negative control discs were placed on two sides of the bacterial culture plate. The size of growth inhibition zone was measured by a blinded independent observer in millimetres.Results. According to the results of disc diffusion test, the mean diameter of growth inhibition zone of A. actinomycetemcomitans around discs impregnated with CHX was larger in both standard (positive control) and biofilm samples of A. actinomycetemcomitans compared to the negative control group (blank disc) (P<0.001).Conclusion. Use of0.2% CHX mouthwash had antibacterial effects on A. actinomycetemcomitans species isolated from peri-implantitis sites.

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Objectives: Intraoral scanners have shown promising results when used as an adjunct or alternative to conventional impression techniques. This study compared the accuracy of digital impression taking using an intraoral scanner versus the conventional technique. Materials and Methods: In this in-vitro experimental study, a typodont molar tooth was prepared as the standard model and scanned by TRIOS intraoral scanner. Ten digital impressions were fabricated as such and intraoral scans were sent to the manufacturers. In the conventional method, using addition silicone impression material, a stone die was fabricated. Using a computer-aided design/computer-aided manufacturing scanner, the die was scanned, and the data were transferred to the software. After the fabrication of frameworks, the replica technique was used. The replicas’ thickness (indicative of the gap between the framework and the model and the accuracy of impression taking) was 12 points. The data were analyzed using student's t-test. Results: The mean thickness of replicas (gap between the internal surface of frameworks and the standard model) at the three points in the buccal, lingual, mesial, and distal sections in the digital impression technique was lower than that in the conventional technique (P<0.0001). In other words, the accuracy of impressions taken by the digital method was significantly higher than those taken by the conventional method. Conclusion: Intraoral digital scanner had significantly higher accuracy than the conventional method in all points. Thus, the digital method can be reliably used as an adjunct or alternative to the conventional method to increase the accuracy of impression taking.

Objective: This study sought to use the mPES to assess various maxillary implant surgical results and placement timing in the esthetic zone. Materials and methods: This cohort study was conducted on 146 patients undergoing immediate, early, and late implantation. They received maxillary single-tooth implants in the anterior region during the past 5 years. Patients were clinically examined to determine their mPES and patient−/implant-related parameters. Simple and multiple nominal regression analyses were applied to show how such parameters correlated with mPES. Results: The results were found to be in three categories namely the most clinically excellent, acceptable, and unacceptable. Although the most frequent clinically excellent results were noted in the late implantation (late 49.0%, early 25.6%, immediate 24.1%); early implantation was the group with the least frequent clinically unacceptable results (late 16.3%, early 4.7%, immediate 14.8%). The mean width of keratinized tissue was significantly more in patients with clinically excellent results (Pvalue = 0.01). Conclusion: Within the limitations of this study, the author(s) drew the following conclusions: (a) the late implant placement was more likely to be reliable and esthetically acceptable, (b) early implant placement remained the safest method to prevent unaesthetic appearance, and (c) Width of keratinized gingiva (≥3 mm) was a significant factor to achieve implant esthetic results. Clinical significance: Maxillary single-tooth implants in the anterior region often have optimal osseointegration and functional performance, but esthetic plays a significant role in the success of these implants. So the aim of the present study was to employ mPES to assess the effect of placement timing and other patient and implant-related variables on esthetic outcomes.

Due to the effect of various impression techniques on accuracy of fi nal cast dimensions and controversies about the best techniques, this study was performed to compare the Splinted and non-splint in open-tray impression techniques on 15 and 25º angled implants. At fi rst steel model in 8 cm diameter and 3 cm height were made with 4 holes to stabilize 4 implants. Two central implants had 12 cm interspace from each other and 17 mm from angled implants. Central implants were perpendicular and the other implants had the divergence of 15 and 25º. The implants and Teries were fabricated using acrylate and polymeric acryl. A total of 30 tery were fabricated (n= 15 in each group). In group A, Open tray with splinted impression copings and group B with splinted impression copings non-splinted. Then, Splinted and non-splint in open-tray impression techniques were evaluated. Each casts were measured by coordinated measuring machine device for implant position. The content of dimensional changes in transfer of implant positions was reported in for the four interspaces (A 1 , A 2 , A 3 and A 4 ). According to the results, changes in transfer of implant in A 1 , A 2 , A 3 and A 4 positions were 19.014±0.04, 15.763±0.01, 62.619±0.05 and 54.019±0.05mm, respectively in Splinted group. In the non-splinted group changes in transfer of implant positions were 18.896±0.05, 15.772±0.01, 62.664±0.02 and 54.063±0.02mm for A 1 , A 2 , A 3 and A 4 positions, respectively. According to the results, signifi cant difference detected in in dimensional accuracy of the resultant casts made from Splinted and non-Splinted impression techniques (P<0.05). These results suggested splinted impression technique is recommended for angulated implants.