Tomographic evaluation of the effect of simvastatin topical use on alveolar bone microarchitecture, pain and swelling after mandibular third molar extraction: a randomized controlled trial.

OBJECTIVES: To evaluate the effect of a collagen sponge containing simvastatin on socket healing in terms of bone microarchitecture through tomographic analysis, pain, and swelling after impacted third molar extraction. MATERIALS AND METHODS: In this single-blind, split-mouth, randomized clinical trial, 29 patients undergoing impacted third molar extraction were allocated into two groups: (i) test group, a collagen sponge containing simvastatin was inserted within the sockets; and (ii) control group, in which sockets retained the clot. Bone volume (BV), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular spacing (Tb.Sp), and gray scale were evaluated using cone beam computed tomography (CBCT) acquired immediately postoperative and 3 months after surgery. Pain, swelling, and wound healing were evaluated using the 10-point visual analogue scale, three extra-oral reference measurements, and the Landry index. RESULTS: In total, 22 participants remained in the study; no loss-to-follow-up was related to the intervention. BV and BV/TV were significantly higher at 3 months postoperatively in the test group compared with the control group and were correlated with greater bone trabeculation. Pain, edema, and the Landry index revealed a greater inflammatory response in the test group during early repair. Simvastatin contributed to bone healing, with no adverse effects or postoperative complications. CONCLUSIONS: The absorbable collagen sponge containing simvastatin improved BV, BV/TV, and trabecular bone, indicating the potential of this drug to induce the formation of autogenous bone. CLINICAL RELEVANCE: Intraosseous statins represent a promising, low-cost, and easy-to-use alternative for alveolar ridge preservation and bone regeneration. TRIAL REGISTRATION: Brazilian Registry of Clinical Trials (REBEC), No. RBR-523N7R.

Effect of resveratrol on the progression of experimental periodontitis in an ovariectomized rat model of osteoporosis: Morphometric, immune-enzymatic, and gene expression analysis.

OBJECTIVE: This study aimed to determine the role of resveratrol (RESV) on the progression of experimental periodontitis (EP) in ovariectomy rats (OVT). BACKGROUND: Estrogen deficiency is the main cause of osteoporosis and is related to higher periodontal attachment loss and reduction of alveolar bone. Zoledronate (ZLD) is an antiresorptive drug used to control osteoporosis but can lead to osteonecrosis of the jaw. RESV, a natural product, can reduce bone loss and control and prevent osteoporosis. Thus, this study aimed at investigating the effect of RESV on the progression of EP in estrogen-deficient rats. MATERIAL AND METHODS: The animals were subjected to the OVT or sham surgery to induce estrogen-deficiency and then were divided into the groups: OVT + RESV (n: 10); OVT + PLAC (n: 10): OVT + placebo; OVT + ZLD +PLA (n: 10); OVT + RESV +ZLD (n: 10): OVT + RESV and ZLD; SHAM (n: 10): non-ovariectomized animals + placebo. To induce estrogen deficiency, the rats were subjected to ovariectomy. Experimental periodontitis was induced by the placement of a ligature at the second maxillary molars. Daily administration of the placebo solution, resveratrol (10 mg/kg), and ZLD (0.1 mg/kg) was carried out for a period 42 days prior to initiation of EP, and then for another 28 days following ligature placement. After euthanasia, the specimens were processed for micro-CT and morphometric analysis of bone loss (linear measurement), and the gingival tissue surrounding the maxillary second molar was collected for the quantification of inflammatory markers using Luminex/MAGPix, of oxidative stress markers using ELISA assay, and gene expression analysis of bone markers, by real-time PCR. RESULTS: Morphometric and micro-CT analysis showed higher bone loss and lower bone density, respectively, in OVT + PLAC when compared to the other groups (P < .05). ZLD treated groups had lower alveolar bone loss, as well as, higher density and percentage of bone volume, when compared to OVT + RESV and SHAM + PLAC groups (P < .05). IL-4 levels were significantly lower in the OVT + PLAC group versus OVT + ZLD +RESV and SHAM + PLAC (P < .05). NADPH oxidase (nicotinamide adenine dinucleotide phosphate oxidase) levels were significantly lower OVT + RESV group when compared to OVT + PLAC (P < .05). OPG mRNA levels were lower in OVT + PLAC compared with the SHAM + PLAC group (P < .05). CONCLUSION: It can be concluded that resveratrol modulated alveolar bone loss during experimental periodontitis progression in estrogen-deficient rats by downregulating NADPH oxidase levels.

Effect of micro-computed tomography reconstruction protocols on bone fractal dimension analysis.

OBJECTIVES: To evaluate the influence of the level of three micro-CT reconstruction tools: beam-hardening correction (BHC), smoothing filter (SF), and ring artefact correction (RAC) on the fractal dimension (FD) analysis of trabecular bone. METHODS: Five Wistar rats' maxillae were individually scanned in a SkyScan 1174 micro-CT device, under the following settings: 50 kV, 800 µA, 10.2 µm voxel size, 0.5 mm Al filter, rotation step 0.5°, two frames average, 180° rotation and scan time of 35 min. The raw images were reconstructed under the standard protocol (SP) recommended by the manufacturer, a protocol without any artefact correction tools (P0) and 35 additional protocols with different combinations of SF, RAC and BHC levels. The same volume of interest was established in all reconstructions for each maxilla and the FD was calculated using the Kolmogorov (box counting) method. One-way ANOVA with Dunnet's post-hoc test was used to compare the FD of each reconstruction protocol (P0-P35) with the SP (α = 5%). Multiple linear regression verified the dependency of reconstruction tools in FD. RESULTS: Overall, FD values are not dependent on RAC (p = 0.965), but increased significantly when the level of BHC and SF increased (p < 0.001). FD values from protocols with BHC at 45% combined with SF of 2, and BHC at 30% combined with SF of 4 or 6 had no statistical difference compared to SP. CONCLUSIONS: BHC and SF tools affect the FD values of micro-CT images of the trabecular bone. Therefore, these reconstruction parameters should be standardized when the FD is analyzed.

Brazilian young dental practitioners' use and acceptance of digital radiographic examinations.

PURPOSE: The aim of this study was to investigate the use and acceptance of digital radiographic examinations by Brazilian dental practitioners in daily practice and to evaluate the advances that have occurred over the past 5 years. MATERIALS AND METHODS: Dental practitioners enrolled in extension courses at the Piracicaba Dental School, University of Campinas, Brazil, responded to a self-administered questionnaire in the years 2011 and 2015. They were asked about sociodemographic factors and their knowledge and use of digital radiographic examinations. Descriptive analysis was performed, as well as the chi-square and Fisher exact tests, with a significance level of 5% (α=0.05). RESULTS: A total of 181 participants responded to the questionnaire in the years 2011 and 2015. Most of the respondents worked in private practice, had graduated within the last 5 years, and were between 20 and 30 years old. In 2011, 55.6% of respondents reported having ever used digital radiographic examinations, while in 2015 this number increased significantly to 85.4% (p<.0001), out of which 71.4% preferred it to conventional images. Moreover, 21.4% of respondents reported having used digital radiographic examinations for more than 3 years. A significant increase in use of intraoral digital radiography (p=0.0316) was observed in 2015. In both years, image quality and high cost were indicated, respectively, as the main advantage and disadvantage of digital radiographic examinations. CONCLUSION: This study showed that digital radiology has become more common in Brazil over the past 5 years. Most of the Brazilian dental practitioners evaluated in 2015 used digital radiographic examinations.

Assessment of the anterior loop of the mandibular canal: A study using cone-beam computed tomography.

PURPOSE: Sufficient area in the interforaminal region is required for dental implant placement, and the anterior loop of the mandibular canal is located within the limits of this area. The aim of this study was to evaluate the prevalence and extent of the anterior loop in a Brazilian sample population using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT images from 250 patients (500 hemimandibles) obtained for various clinical indications were randomly selected and evaluated to determine the presence and length of the anterior loop. The length of the anterior loop was then compared based on gender, age, and the side of the mandible. The data were analyzed using the Pearson chi-square test and linear regression analysis. RESULTS: An anterior loop was identified in 41.6% of the cases, and its length ranged from 0.25 mm to 4.00 mm (mean, 1.1±0.8 mm). The loop had a greater mean length and was significantly more prevalent in males (p=0.014). No significant differences were found between the right and left sides regarding length (p=0.696) or prevalence (p=0.650). CONCLUSION: In this study, a high prevalence of the anterior loop of the mandibular canal was found, and although its length varied greatly, in most cases it was less than 1 mm long. Although this is a prevalent anatomical variation, safety limits for the placement of implants in this region cannot be established before an accurate evaluation using imaging techniques in order to identify and preserve the neurovascular bundles.