Antimicrobial Efficacy and Dentin Collagen Damage Caused by Calcium Hypochlorite and Sodium Hypochlorite.

This study aimed to evaluate the antimicrobial activity of calcium hypochlorite (Ca (OCl)2) and sodium hypochlorite (NaOCl) using confocal laser scanning microscopy (CLSM) and dentin organic matrix alteration by picrosirius staining and light microscopy (LM). Samples of human extracted teeth were infected with Enterococcus faecalis by centrifugation of the bacterial suspension and were treated with Ca(OCl)2 or NaOCl at 0.5%, 2.5%, and 6% for 15, 30, and 60 seconds. CLSM and viability staining were used to quantitatively analyze the proportions of dead/live bacteria in the canal lumen and border of the root canal. The data were analyzed by ANOVA and Fisher test. For LM analysis, one hundred bovine teeth were randomly divided into 10 test groups (n=10): G1- Without treatment; G2- 17% EDTA; G3- 6% NaOCl; G4- 6% NaOCl + EDTA; G5- 0.5% Ca(OCl)2; G6- 0.5% Ca(OCl)2 + EDTA; G7- 2.5% Ca(OCl)2; G8- 2.5% Ca(OCl)2 + EDTA; G9- 6% Ca(OCl)2; G10- 6% Ca(OCl)2 + EDTA. The samples were fragmented and stained with Picrosirius. Data were analyzed by Kruskal-Wallis and Dunn (P<0.05). There was a strong correlation between the results of the canal lumen and the border of the root canal (r=0.962). Both hypochlorites at a concentration of 0.5% showed less microbial reduction compared to 2.5% and 6% (P<0.05). There was less antimicrobial activity at 15 seconds compared to 30 and 60 seconds (P<0.05). Ca(OCl)2 and NaOCl showed similar results at the same concentrations (P>0.05). In conclusion, Ca(OCl)2 caused fewer alterations to the dentin organic matrix at concentrations of 0.5% and 2.5%. Ca(OCl)2 presents antimicrobial activity similar to NaOCl, and collagen damage is concentration-dependent.

Evaluation of dental trauma associated with cycling accidents in a city in the south of Brazil: an observational study / Avaliação de traumatismos dentários associados a acidentes com bicicletas em uma cidade do sul do Brasil: um estudo observacional

Aim: to evaluate the cyclists' profile and the frequency of dental trauma associated with cycling in a southern city in Brazil. Materials and Methods: a questionnaire was applied to 234 cyclists with at least 18 years old. The variables of interests were: sociodemographic data, data related to the profile of users, and data on the occurrence of all traumas and dental traumas. Descriptive and inferential statistical analyses were carried out (α=5%). Results: The mean age of participants was 31.38 ± 11.6 years, ranging from 14 to 67 years. The majority of the participants were male (62.8%), had attended higher education (45.7%), and had incomes equivalent to 1 to 3 times the minimum wage (39.3%). The main reason given for riding a bicycle was leisure (35.9%). Users of their own bicycles had fewer items of mandatory safety equipment fitted to their bicycles than users of rented bicycles (Student's t test, P<0.0001). However, study participants riding their own bicycles wore personal protective equipment more frequently than renters (Student's t test, P<0.0001). Moreover, 33.7% of the respondents reported having suffered an accident, and 25% had traumatized some part of the body. Among those who reported traumas, 20% (4/20) had suffered traumas to hard dental tissues and supporting structures. Discussion: Dental trauma was not frequent in a population predominantly from an urban area that uses bicycles, especially for leisure, despite the prevalence of accidents involving bicycle use. Conclusion: Health education campaigns should emphasize the importance of personal protective equipment for cyclists and of safety items fitted to bicycles, whether cyclists' own or rented.

Objetivo: avaliar o perfil dos ciclistas e a frequência de traumatismo dentário associado ao ciclismo em uma cidade do sul do Brasil. Materiais e Métodos: aplicou-se um questionário a 234 ciclistas com idade mínima de 18 anos. As variáveis ​​de interesse foram: dados sociodemográficos, dados relacionados ao perfil dos usuários e dados sobre a ocorrência de todos os traumatismos e traumas dentários. Foram realizadas análises estatísticas descritivas e inferenciais (α=5%). Resultados: A idade média dos participantes era de 31,38 ±11,6 anos, variando de 14 a 67 anos. A maioria dos participantes era do sexo masculino (62,8%), tinha curso superior (45,7%) e renda equivalente a 1 a 3 salários mínimos (39,3%). O principal motivo para andar de bicicleta foi lazer (35,9%). Usuários de suas próprias bicicletas tinham menos itens de equipamentos de segurança obrigatórios instalados do que os usuários de bicicletas alugadas (teste t de Student, P<0,0001). Porém, participantes do estudo que andavam em sua própria bicicleta usavam equipamentos de proteção individual mais frequentemente do que os locatários (teste t de Student, P<0,0001). Ainda, 33,7% dos entrevistados relataram ter sofrido algum acidente e 25% traumatizado alguma parte do corpo. Entre os que relataram traumatismos, 20% (4/20) sofreram traumas em tecidos duros dentais e estruturas de suporte. Discussão: O traumatismo dentário não foi frequente em uma população predominantemente de área urbana que utiliza bicicletas, principalmente para lazer, apesar da prevalência de acidentes envolvendo o uso de bicicletas. Conclusão: As campanhas de educação em saúde devem enfatizar a importância dos equipamentos de proteção individual dos ciclistas e dos itens de segurança instalados nas bicicletas, sejam elas próprias ou alugadas.

Effect of reciprocating instrumentation on chlorhexidine substantivity on human dentin: chemical analysis followed by confocal laser microscopy

The present research analyzed the reciprocating instrumentation associated to chlorhexidine (CHX) substantivity as its correlation with E. faecalis viability in ex vivo root canals. Eighty extracted single-rooted human teeth were used, being 40 to high-performance liquid chromatography (HPLC) and 40 to confocal laser scanning microscopy (CLSM). In both, teeth were decoronated and the cervical third was prepared. In the CLSM analysis, the root canals were inoculated with E. faecalis for 14 days. Samples were divided into 4 groups (n=10) according to instrumentation technique: no instrumentation and irrigation with distilled water (control); manual instrumentation (K-File); rotary instrumentation (ProTaper Next); and reciprocating instrumentation (Reciproc R25). Two percent chlorhexidine was applied as irrigating substance in experimental groups. Longitudinal grooves resulted in 2 halves root and 20 proof bodies in each group. Samples were divided by chance in two groups (n=10) and the outcomes were evaluated after two days and one week. The retained chlorhexidine and live cells after instrumentation techniques in each evaluation time was measured by HPLC and CLSM, respectively. Specific analysis was applied for experimental tests (p≤0.05). Both rotary as well as reciprocating techniques significantly reduced the amount of chlorhexidine on dentin in all observation periods (p<0.05). After evaluation times, all experimental groups presented lower live cells compared to control, but without statistically difference. Intragroup comparisons in times of evaluation showed no differences in instrumentation techniques, in chlorhexidine retention and number of live cells (p>0.05). Reciprocating instrumentation does not interfere on chlorhexidine substantivity.