BACKGROUND: Bleaching is a conservative approach to improve tooth colour. Laser irradiation accelerates the process by activating the hydrogen peroxide (HP) bleaching agent. However, there is little data examining whether this might result in pulp injury by enhancing HP penetration and diffusion. This study measured HP penetration into the pulp chamber with different bleaching techniques. METHODS: Fifty extracted central maxillary incisors were collected, disinfected, root treated and stored in sterile saline solution. The pulp chambers were filled with an acetate buffer solution. Bleaching was performed with one of four methods: 1. Conventional in-office bleaching; and accelerated bleaching using 2. :yttrium-aluminium-garnet (Nd:YAG), 3. 1w Diode, and 4. 1.5w Diode lasers. A fifth control Group received no treatment. The buffer solution was drained and stained by colourimetric spectrophotometry to determine optical densities, which were analyzed by one-way ANOVA followed by Tukey honest significant difference (HSD) test. RESULTS: The greatest penetration occurred with the conventional in-office bleaching procedure (2.232 ± 0.39μg), while the least was seen with Diode (1w) laser-assisted bleaching (0.31 ± 0.28μg). : Provided the manufacturer's recommendations are followed, laser acceleration does not exacerbate penetration of HP into the pulp chamber.

OBJECTIVE:To assess the incidence of prostate adenocarcinoma in patients undergoing radical cystoprostatectomy due to bladder cancer in Iranian men. MATERIALS AND METHODS: Fifty cystoprostatectomy specimens removed due to bladder malignancy (2004-2005) at two referral centers (Shaheed Modarress and Shaheed Labbafinejad Hospitals, Tehran, Iran) were examined for the coincidental finding of prostate cancer (PCa). At the time of surgery the patient's serum PSA was less than 4 ng/mL and there were no suspicious lesions by digital rectal examination. Pathologic grade, stage, morphometric volume, number of tumor foci and association with areas of high grade prostatic intraepithelial neoplasia (HGPIN) were assessed by light microscopy. All specimens were totally embedded and whole-mounted. Clinically significant cancers were defined as tumors with 0.5 mL volume, Gleason pattern 4 or 5, pT3, positive surgical margin, and multifocality > 3. RESULTS: Incidentally detected cancer was found in 7 (14%) of cystoprostatectomy specimens. HGPIN was present in 1 (14.3%) of the cystoprostatectomies with incidentally detected prostate cancer. None of cystoprostatectomies without prostate cancer had HGPIN. Four (57%) of the detected cancers were significant. CONCLUSION: We conclude that incidentally detected prostate cancer in Iran is lower than the rates reported in other countries. Further studies are warranted for better declaration of variability of prostate cancer between different ethnic groups.