Background: Different surgical approaches have been proposed to treat periimplantitis defects with limited effectiveness and predictability. Laser has been proposed as an effective tool to assist in bacterial decontamination and modulating peri-implant tissue inflammation. The aim of this pilot clinical trial was to evaluate the adjunctive benefits of Er:YAG laser irradiation for regenerative surgical therapy of peri-implantitis-associated osseous defects. Methods: Twenty-four patients diagnosed with peri-implantitis with a radiographic infrabony defect were randomized into two groups. Both test and control groups received the following treatment: open flap mechanical debridement, supracrestal implantoplasty, bone grafting using a mixture of human allograft with demineralized bone matrix human allograft putty, and then covered with acellular dermal matrix membrane. The only difference in the test group was the adjunctive use of Er:YAG laser to modulate and remove inflammatory tissue as well as to decontaminate the implant surface. Clinical assessments, including pocket depth (PD), clinical attachment level (CAL), and gingival index (GI) were performed by calibrated masked examiners for up to 6 months following surgery. Standardized radiographs were also taken to evaluate linear bone gain and defect bone fill. Student t-tests were used to analyze those clinical parameters. Results: Both groups showed significant reductions in PD, GI, and CAL gain overtime. The test group demonstrated significantly higher PD reductions at the site level compared to the control group (2.65 ± 2.14 versus 1.85 ± 1.71 mm; test versus control, P = 0.014). There were no statistical differences found in CAL gain (1.90 ± 2.28 versus 1.47 ± 1.76 mm; test versus control), GI reduction (-1.14 ± 1.15 versus-1.04 ± 0.89; test versus control), radiographic linear bone gain (1.27 ± 1.14 versus 1.08 ± 1.04 mm; test versus control) or proportional defect size reduction (-24.46 ± 19.00% versus-15.19 ± 23.56%; test versus control). There was a positive trend for test patients on PD reduction and CAL gain found in narrow infrabony 378

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Bisphosphonates (BPs) are drugs commonly used in the treatment of various disease arising or affecting bone tissue. There is a standard use in bone neoplasia and metastasis, hormonal and developmental disorders as well as for compensation of adverse effects in several medical therapies. Many in-vivo and in-vitro studies have assessed the effi cacy of this drug and its function in cellular scale. In this concern, BPs are described to inhibit the resorptive function of osteoclasts and to prevent apoptosis of osteoblasts and osteocytes. They can preserve the osteocytic network, reduce fracture rate, and increase the bone mineral content, which is therapeutically used. Connexin 43 (Cx43) is a crucial molecule for basal regulation of bone homeostasis, development, and differentiation. It is described for signal transduction in many physiological and pathological stimuli and recently to be involved in BP action.

Introduction: This study aimed to assess the Scanning Electron Microscope (SEM) analysis of tooth surface irradiated by erbium:yttrium-aluminum-garnet (Er:YAG) laser with various parameters. Methods: Number of 25 extracted human third molars free of caries were used in this study. The teeth were put into 5 groups for laser irradiation as follows: group 1 (power: 0.5 W, Energy: 50 mJ); group 2 (power: 1 W, Energy: 100 mJ); group 3 (power: 1.5 W, Energy: 150 mJ); group 4 (power: 2 W, Energy: 200 mJ); group 5 (power: 2.5 W, Energy: 250 mJ). All samples were prepared by repetition rate of 10 Hz and duration of 230 µs, using a non-contact handpiece at a distance of 4 mm. Then, the samples were prepared for SEM examination. Results: SEM evaluation of every 25 samples, treated by Er:YAG, showed that all groups had exposed dentinal tubules without any melted area or cracks. Conclusion: In this study we used SEM to investigate ablated dentine with different parameters of Er:YAG laser energy. Our findings support these conclusions. All powers of laser below 3 W are proper for ablation, and make no cracks.

Despite the increasing demand for fiber-reinforced composite (FRC) posts, their bonding to root canals is still subject to debate. Endodontic sealers may affect the bond strength between fiber posts and root canal dentin. Aim: To compare the effects of different sealers on fiber post bond strength. Methods: Sixty teeth were divided into 4 groups according to obturation method: GI, gutta-percha without any sealers; GII, gutta-percha and AH26 resin-based sealer; GIII, RealSeal point and RealSeal resin-based sealer, GIV, Guttaflow. Fiber posts were cemented into root canals. Specimens were sectioned, and the bond strength was measured in the middle area. The failure mode was evaluated. Data were analyzed by one-way ANOVA and post hoc test. Results: The highest bond strength was observed in the control group (2.95±1.12), and the least was in the Guttaflow group (1.15±0.78). There was a significant difference between bond strengths of the control and Guttaflow groups and between AH26 and Guttaflow groups (p<0.05). The failure mode was mainly adhesive between dentin and resin cement in all groups. Conclusions: Sealers may have a negative effect on the bond strength of fiber posts to root canal dentin.

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IntroductionIn recent years, tooth whitening has become one of the most growing oral care sectors, boosted by patients, demanding both healthy mouth and attractive smile.1 As tooth color relies on the composition of tooth tissues, any chemical, mechanical or biological change can damage the esthetic equilibrium of the smile.2 Bleaching is a simple, non-restorative and noninvasive treatment for discolored teeth that is capable of satisfaction of the high demanding patients. So it has attracted much interest from the profession. Bleaching systems today are based on hydrogen peroxide as the active agent and are often activated by heat or light.3 Hydrogen peroxide acts as a strong oxidizing agent through the formation of free radicals and reactive molecules which attack dark colored macromolecules and break them into smaller and less colored ones. 4 Although other products such as carbamide peroxide or sodium perborate are available for bleaching, hydrogen peroxide is still considered to be the most effective and popular agent, since it is available in a range of formulations, concentrations and activation modes. In-office bleaching can provide significant brightness after only one session of treatment, but achievement of optimum results may require multiple sessions or longer time of application of the bleaching agents. 6,7 However, this may increase the risk of tooth sensitivity 8 and cause certain amount of enamel matrix degradation. 9Acceleration of hydrogen peroxide decomposition can be carried out through energy absorption from external source of energy like heat or laser, providing better patient compliance and may eradicate the side effects of high concentrated hydrogen peroxide.10,11 Because of tooth temperature concerns, lasers are now more preferred. Lasers such as diode (LED), halogen, Nd:YAG etc can be highlighted. Abstract Introduction: Today, bleaching is a routine noninvasive alternative for treatment of discolored teeth. The aim of this study was to determine whether conventional or laser activated bleaching predispose teeth to develop caries or not. Methods: Sixty human molars were mounted on acrylic cylinders and their Knoop microhardness (KHN) as well as DIAGNOdent (DD) values were recorded. They were divided into 4 experimental groups; G1) conventional bleaching with 40% hydrogen peroxide gel, G2) Diode laser assisted bleaching with same gel, G3) Nd:YAG laser assisted bleaching with the same gel, G4) control group. After bleaching, all samples were subjected to a three day pH cycling regimen and then, KHN and DD values were measured. Results: All groups had significant reduction in KHN values. It seems that there is no statistically meaningful difference between changes in enamel microhardness of the sample groups and all groups have changed in a similar amount. Reduction of DD scores were significant in Diode laser and conventional groups, however changes in Nd:YAG laser and control groups were not significant. Changes in DD values have followed a similar pattern among groups, except in G1-G4 a...

Aim Since there is limited study to assist in an evidenced‐based decision whether to extract or preserve a structurally compromised tooth, the aim of this retrospective study was to investigate the long‐term survival rate of tooth preservation after crown lengthening procedure (CLP) and restorative treatments. Methods Electronic and paper chart of patients received CLP in our graduate clinic from 1990 to 2015 were reviewed. Statistical analysis was done using Cox regression analysis and Kaplan–Meier estimator. Results A total of 766 coded charts were initially collected. Four hundred and fourteen cases were included in the final analysis. The Kaplan–Meier estimate shows a cumulative survival rate of 88.3% in 5 years, 78.4% in 10 years and 68.1% in 15 years. In terms of reasons for failure, restorative problem such as recurrent decays was the main issue (35.2%), followed by fracture (29.6%), endodontic complications (23.9%) and periodontal breakdown (11.3%). Conclusions Within the limitation of this study, structurally compromised teeth have a reasonable long‐term survival rate close to 80% after 10 years in a teaching institute. Patients with high fracture or caries risk may pose a higher chance of failure. Objective information should be presented to the patient to arrive at an evidence‐based decision.