Influence of systemic antibiotic therapy on the development and progression of induced apical periodontitis in Wistar rats.

The aim of this study was to investigate the influence of systemic antibiotic therapy on the development and progression of induced apical periodontitis (AP) in Wistar rats. Fifty-six rats were submitted to pulp exposure of the lower left first molar for the induction of AP. On the same day, intraperitoneal antibiotic therapy was administered once a day, for 15 days, until euthanasia. The groups were formed according to the different treatments (n = 8): C-control; GEN-treated with gentamicin (10 mg/Kg); AC-treated with amoxicillin (100 mg/Kg); MZ-treated with metronidazole (40 mg/Kg); AMP-treated with ampicillin (100 mg/Kg); AMC group-treated with amoxicillin + clavulanic acid (100 mg/kg); CLI-treated with clindamycin (60 mg/kg). After euthanasia, the jaws were collected and processed for (1) histological and histometric analysis using hematoxylin and eosin staining, (2) analysis of collagen fibers using Picrosirius Red staining and (3) bacteriological analysis using Brown-Brenn staining. The data were analyzed statistically (p < 0.05). AP induction was confirmed in all groups. The AMC group had the lower intensity of inflammatory infiltrate (p = 0.028) and less periapical bone resorption compared to control (p = 0.006). Regarding collagen maturation, PSR staining revealed a predominance of mature collagen fibers in all groups. The AC and AMC groups had the lower amount of mature fibers and the highest amount of immature fibers, compared to all other groups (p < 0.001). All groups showed bacterial contamination; however, the AC and AMC groups showed a lower extent of bacterial contamination compared to the control (p < 0.001). It can be concluded that systemic antibiotic therapy influences the development and progression of induced AP.

Influence of different types of light on the response of the pulp tissue in dental bleaching: a systematic review.

OBJECTIVES: This systematic review (PROSPERO register: CRD42016053140) investigated the influence of different types of light on the pulp tissue during dental bleaching. MATERIALS AND METHODS: Two independent authors conducted a systematic search and risk of bias evaluations. An electronic search was undertaken (PubMed/Medline, Embase, The Cochrane Library, and other databases) until May 2017. The population, intervention, comparison, outcomes (PICO) question was: "Does the light in dental bleaching change the response of the pulp to the bleaching procedure?" The intervention involved pulp tissue/cells after bleaching with light, while the comparison involved pulp tissue/cells after bleaching without light. The primary outcome was the inflammation/cytotoxicity observed in pulp after bleaching. RESULTS: Out of 2210 articles found, 12 articles were included in the review; four were in vivo studies (one study in dogs/others in human), and eight were in vitro studies (cell culture/with artificial pulp chamber or not). The light source used was halogen, light-emitting diode (LED), and laser. Only one in vivo study that used heat to simulate light effects showed significant pulp inflammation. Only two in vitro studies demonstrated that light influenced cell metabolism; one using halogen light indicated negative effects, and the other using laser therapy indicated positive effects. Given that animal and in vitro studies have been identified, there remain some limitations for extrapolation to the human situation. Furthermore, different light parameters were used. CONCLUSIONS: The effects of dental bleaching on the pulp are not influenced by different types of light, but different light parameters can influence these properties. CLINICAL RELEVANCE: There is insufficient evidence about the influence of different types of light on inflammation/cytotoxicity of the pulp.

Anti-inflammatory potential of a carvedilol gel in the pulpal tissue of rats after dental bleaching: A histopathological evaluation.

AIM: Carvedilol is an antioxidant that decreases inflammation in periodontitis. The hydrogen peroxide (H2 O2 ) of bleaching gel causes inflammation and necrosis of the dental pulp. In the present study, we evaluated the anti-inflammatory potential of carvedilol in the pulp of rats after bleaching. METHODS: The right upper molars of rats received 35% H2 O2 (1× 30 minutes), and the left upper molars were used as the control. Half of the rats received carvedilol gel (1× 10 minutes), forming the following groups: bleached, bleached followed by carvedilol (bleached+carvedilol), and control. After 2 and 30 days (N = 7 hemi-maxillae/group), the rats were killed for histological evaluation, and statistical tests were performed (P < 0.05). RESULTS: After 2 days, the bleached group showed necrosis in the occlusal third of the coronal pulp, and in the bleached+carvedilol group, severe inflammation (P > 0.05), both different from the control (P < 0.05). In the middle third, the bleached group showed severe inflammation, and the bleached+carvedilol group showed moderate inflammation (P > 0.05), with the only difference between the bleached and control groups (P < 0.05). In the cervical third, the bleached group showed moderate inflammation, and the bleached+carvedilol group showed mild inflammation (P > 0.05). The difference again was only between the bleached and control groups (P < 0.05). At 30 days, there was no inflammation and a marked amount of tertiary dentin in bleached teeth (P > 0.05). CONCLUSION: Carvedilol gel has the potential of minimizing H2 O2 damage, especially in deep regions of the dental pulp of rats after bleaching.