Influência de substâncias irrigadoras endodônticas na microdureza da dentina radicular: revisão integrativa / Influence of endodontic irrigation substances on the microdurity of the radicular dentin: integrative review

As soluções de irrigação são essenciais como auxiliares na limpeza e desinfecção do sistema de canais radiculares (SCR). Entretanto, essas substâncias químicas podem gerar alterações na composição da dentina. Assim, o presente estudo teve como objetivo avaliar, por meio de uma revisão integrativa, os efeitos do hipoclorito de sódio (NaOCl) a 1%; 2,5%; 3%; 5%; 5,25%; 6% e 17%; digluconato de clorexidina (CHX) a 2% e EDTA 2,5%; 5%; 15% e 17% sobre a microdureza da dentina do canal radicular após sua utilização como solução irrigadora. Foi realizada uma revisão integrativa nas bases de dados: PubMed, Cochrane e Lilacs, utilizando-se os seguintes descritores em inglês: "irrigating solutions"; "chelaling agentes"; "dentin microhardness"; "EDTA"; "sodium hypochlorite"; "chlorhexidine gluconate". Foi utilizado o conector "and" associando dentin microhardness aos outros descritores. Critérios de inclusão: Artigos científicos na área da odontologia, escritos em inglês e português que aborda o tema "As soluções de hipoclorito de sódio (NaOCl), digluconato de clorexidina (CHX) e EDTA influenciam na microdureza da dentina radicular?''. Critérios de exclusão: artigos repetidos em mais de uma base de dados, livros, teses de doutorado, dissertações de mestrado, resumos e trabalhos publicados em congresso. Fortes evidências indicam que o hipoclorito de sódio, digluconato de clorexidina e EDTA influenciam na microdureza da dentina radicular, quando utilizadas como solução irrigadora durante o tratamento endodôntico... (AU)

Irrigation solutions are essential as an aid in cleaning and disinfecting the root canal system (SCR). However, these chemicals can cause changes in the composition of dentin. Thus, the present study aimed to evaluate, through an integrative review, the effects of 1% sodium hypochlorite (NaOCl); 2.5%; 3%; 5%; 5.25%; 6% and 17%; 2% chlorhexidine digluconate (CHX) and 2.5% EDTA; 5%; 15% and 17% on the microhardness of root canal dentin after its use as an irrigating solution. An integrative review was carried out in the databases: PubMed, Cochrane and Lilacs, using the following descriptors in English: "irrigating solutions"; "chelaling agents"; "dentin microhardness"; "EDTA"; "sodium hypochlorite"; "chlorhexidine gluconate". The "and" connector was used, associating dentin microhardness with other descriptors. Inclusion criteria: Scientific articles in the field of dentistry, written in English and Portuguese that address the topic "Do solutions of sodium hypochlorite (NaOCl), chlorhexidine gluconate (CHX) and EDTA influence the microhardness of root dentin?". Exclusion criteria: articles repeated in more than one database, books, doctoral theses, master's dissertations, abstracts and papers published in congress. Strong evidence indicates that sodium hypochlorite, chlorhexidine gluconate and EDTA influence the microhardness of root dentin when used as an irrigating solution during endodontic treatment... (AU)

Analysis of the shelf life of chitosan stored in different types of packaging, using colorimetry and dentin microhardness

OBJECTIVES: Chitosan has been widely investigated and used. However, the literature does not refer to the shelf life of this solution. This study evaluated, through the colorimetric titration technique and an analysis of dentin micro-hardness, the shelf life of 0.2% chitosan solution. MATERIALS AND METHODS: Thirty human canines were sectioned, and specimens were obtained from the second and third slices, from cemento-enamel junction to the apex. A 0.2% chitosan solution was prepared and distributed in 3 identical glass bottles (v1, v2, and v3) and 3 plastic bottles (p1, p2, and p3). At 0, 7, 15, 30, 45, 60, 90, 120, 150, and 180 days, the specimens were immersed in each solution for 5 minutes (n = 3 each). The chelating effect of the solution was assessed by micro-hardness and colorimetric analysis of the dentin specimens. 17% EDTA and distilled water were used as controls. Data were analyzed statistically by two-way and Tukey-Kramer multiple comparison (α = 0.05). RESULTS: There was no statistically significant difference among the solutions with respect to the study time (p = 0.113) and micro-hardness/time interaction (p = 0.329). Chitosan solutions and EDTA reduced the micro-hardness in a similar manner and differed significantly from the control group (p < 0.001). Chitosan solutions chelated calcium ions throughout the entire experiment. CONCLUSIONS: Regardless of the storage form, chitosan demonstrates a chelating property for a minimum period of 6 months.

Morphological Study and Analysis of Microhardness and Permeability of the Furcation of Maxillary Premolars

Abstract The morphology, microhardness and dentin permeability of the furcation region of maxillary premolars were evaluated. Ten premolars were cut lengthwise and the furcation region was delimited. In one group (n=10) microhardness was measured in the buccal, central and palatal regions, in the outer middle and inner layers of the furcation, and in the buccal and palatal regions adjacent to the furcation. Knoop hardness was tested with 10 g load for 15 s. Data were analyzed statistically by ANOVA and Tukey-Kramer test (a=0.05). In the other group (n=10) confocal microscopy was used to study dentin morphology. Other 10 specimens were instrumented with ProTaper and immersed in 10% copper sulfate for analysis of permeability under light microscopy. About microhardness, there was no significant difference (p>0.05) among the buccal (39.9±3.1), central (39.5±4.4) and palatal (39.7±5.0) regions of the furcation, or between these regions and the adjacent buccal (39.1±5.8) and palatal (39.7±5.8) regions (p>0.05). The inner layer (42.3±3.7) had significantly higher microhardness (p<0.05) than the outer layer (37.1±3.9). There was a tendency of calcification of the dentinal tubules from the outer towards the inner layer. The percentage of stained area was 12.45±2.0%, restricted to the outer layer. The buccal, central and palatal regions of the furcation as well as the buccal and palatal adjacent regions had similar microhardness values. In conclusion, the inner dentin layer is harder than the outer dentin layer. The dentinal tubules are sinuous and intertwine towards the middle layer. Dye penetration is restricted to the outer layer.

Resumo Estudou-se a morfologia, microdureza e permeabilidade dentinária da furca de pré-molares superiores. Dez pré-molares tiveram a porção oclusal da coroa e os terços radiculares médio e apical removidos. Cortou-se longitudinalmente o remanescente e delimitou-se a furca. As hemi-secções foram distribuídas em dois grupos. Num (n=10), mediu-se a microdureza nas regiões vestibular, central e palatina, nas camadas externa, média e interna e nas porções vestibular e palatina adjacentes à furca. Utilizou-se dureza Knoop, carga de 10 g por 15 s. Os dados foram analisados pelo teste ANOVA e Tukey-Kramer (a=0.05). No outro grupo (n=10) utilizou-se microscopia confocal para estudo da morfologia da dentina. Outros 10 espécimes foram instrumentados com Protaper e NaOCl a 1% e imersos em sulfato de cobre a 10% para análise da permeabilidade. Após preparo histológico os espécimes foram analisados em fotomicroscópio. Não houve diferença significante (p>0,05) entre a microdureza das regiões vestibular (39,9±3,1), central (39,5±4,4) e palatina (39,7±5,0), nem entre essas regiões e as adjacentes vestibular (39,1±5,8) e palatina (39,7±5,8) (p>0,05). A camada interna (42,3±3,7) é mais dura que a externa (37,1±3,9) (p<0,05). Há uma tendência dos canalículos calcificarem no sentido da camada externa para a interna. A porcentagem de área corada foi de 12,45±2.0 e restrita à camada externa. As regiões vestibular, central e palatina da furca, bem como as adjacentes vestibular e palatina apresentaram microdureza semelhante entre si. A camada interna apresentou-se mais dura que a externa. Os canalículos dentinários eram sinuosos e se entrelaçaram em direção à camada média. A penetração de corantes se restringiu à camada externa.