Aim:This study aimed to evaluate the cleaning protocol of dentin impregnated with epoxy resin-based sealer (AH Plus) and the effects on the adhesive interface using 95% ethanol (E) or formamide solution (F) associated with microabrasion with glass microparticles (M).Methodology:Forty dentin specimens were impregnated with sealer (AH Plus). Specimens were cleansed according to the following protocols (n = 10): G1 (E); G2 (F); G3 (E = M); and G4 (F = M). No treatment was performed in G5 (control). Specimens were subjected to standard error of the mean to evaluate the residues persistence (×500) and open dentinal tubules counting (×2000). Another fifty specimens were subjected to similar procedures and cleaning protocols. Seven days later, composite-resin-made specimens were performed on dentin using etch-and-rinse adhesive system, then submitted to microshear test.Results:G2 and G4 showed higher residues' persistence and lower incidence of open dentinal tubules than G1 and G3 (P < 0.05). No difference was found between G1 and G3 or G2 and G4 (P > 0.05). Adhesive system bond strength was similar in all groups (P > 0.05).Conclusions:Microabrasion negatively affected the epoxy resin-based sealer residues' removal protocols' action; all groups presented residues on the dentin surface. However, 7 days later, the protocols did not affect the bond strength of adhesive system to sealer-impregnated dentin.

PhD,%Araraquara%Dental%School,%Univ%Estadual%Paulista,%Araraquara,%SP,%Brazil*% PhD,%Dental%School,%Rio%Grande%do%Sul%Federal%University,%Porto%Alegre,%RS,%Brazil**% Correspondence:%miltoncarloskuga@hotmail.com%(KUGA%MC)%|%Received%26%Aug%2013%Received'in'revised'form%01%Sep%2013%Accepted%04%Sep%2013% % % JORDÃO5BASSO,%Keren%Cristina%Fagundes*% KUGA,%Milton%Carlos*% KEINE,%Katia%Cristina*% GALOZA,%Marina%Oliveira%Gonçalves*% SÓ,%Marcus%Vinicius%Reis**% MOLARS% % % ABSTRACT' % PURPOSE:%The%purpose%of%this%study%was%to%evaluate%the%increase% of%the%cervical%area%and%dentin%thickness%in%mesial%and%distal%walls% of% the% mesial% canals% from% mandibular% molars% after% the% use% of% LA% Axxess% (LA),% CP% Drill% (CP)% and% Gates[Glidden% (GG)% rotary% instruments.% MATERIAL' AND' METHODS:% Sixty% root% canals% from% thirty% mandibular% first% % molar% were% sectioned% 3% mm% below% the% cement[enamel% junction,% divided% in% 3% groups% (n% =% 20% root% canals,% each)%according%to%rotary%instrument%used,%and%the%cervical%images% were% captured% before% and% after% pre[enlargement% instrumentation.% The% increase% of% the% instrumented% cervical% area% (mm2)% and% the% dentin% removal% thickness% (mm),% at% mesial% and% distal% walls% were% calculated% using% Image% tools% software,% by% comparison% of% images.% Data%were%analyzed%by%ANOVA%and%Tukey%tests%(p=0.05).%RESULTS:% All% rotary% instruments% promoted% thickness% reduction% in% dentin% walls.% In% mesial% wall,% all% rotary% instruments% promoted% similar% thickness% reduction% of% dentinal% wall% and% did% not% differ% from% each% other% (p>0.05).% In% distal% wall,% LA% Axxess% instrument% promoted% higher%dentin%thickness%reduction%than%other%groups%(p<0.05).%The% three% rotary% instruments% promoted% different% increase% at% the% instrumented% cervical% area% (p<0.05),% LA% promoted% the% highest% increase% area% and% GG% and% CP% presented% similar% results.% CONCLUSION:% LA% 20/0.06% promoted% the% highest% thickness% reduction%in%distal%wall%and%increase%of%cervical%area%of%root%canal.% On%the%other%hand,%CP%was%the%safest%instrument,%with%lower%dentin% removal%of%distal%wall%and%similar%increased%area%to%GG.% ' ' ' ' ' KEYWORDS' % Cervical%preparation.%Root%canal%treatment.%Rotary%instruments.%

ResumoObjetivo: Avaliar o efeito da dentina sobre o pH e a atividade antimicrobiana de formulações com hidróxido de cálcio. Material e método: O pH e a atividade antimicrobiana das formulações (G1-polietilenoglicol, G2-glicerina e paramonoclorofenol canforado ou G3-clorexidina) foram analisados nas formulações puras (G1A, G2A e G3A) ou acrescidas de dentina em pó (G1B, G2B e G3B). Tubos de polietileno foram preenchidos com uma das formulações e imersos em água destilada. O pH foi analisado após 24 horas, 7, 14 e 21 dias. A atividade antimicrobiana foi avaliada sobre Enterococcus faecalis (ATCC 29212), através do teste de difusão em ágar. Os resultados foram submetidos aos testes de ANOVA e Tukey (p=0,05). Resultado: A dentina não exerceu efeito sobre o pH das formulações, exceto ocasionando a redução em G1, no período de 24 horas (p<0,05). Nas demais formulações, não houve interferência da dentina sobre o pH (p>0,05). Quando comparados entre os grupos, em 24 horas e 7 dias, G1A e G1B apresentaram menor pH (p<0,05). Em 14 dias, G2A, G2B, G3A e G3B demonstraram similar pH (p>0,05), assim como entre G3B e G1A (p>0,05). Em 21 dias, todas as formulações demonstram semelhante pH (p>0,05). Os resultados em ordem decrescente da atividade antimicrobiana foram G2A=G2B>G3A=G3B>G1A=G1B (p<0,05). Conclusão: A dentina não interferiu no pH e na atividade antimicrobiana das diferentes formulações com hidróxido de cálcio, exceto na associação com o polietilenoglicol, em que ocasionou a redução do pH apenas no período de 24 horas. A formulação com paramonoclorofenol canforado apresentou maior atividade antimicrobiana, seguida da clorexidina e do polietilenoglicol.Descritores: Cálcio; endodontia; Enterococcus faecalis; pH. AbstractObjective: To evaluate the dentin effect on pH and antimicrobial activity of the calcium hydroxide chemical formulations. Material and method: pH and antimicrobial activity of calcium hydroxide formulations were evaluated (G1-polyethyleneglycol, G2-glycerin and camphorated paramonochlorophenol and G3-chlorhexidine). The formulations were evaluated alone (G1A, G2A e G3A) or with dentin powder (G1B, G2B and G3B). Polyethylene tubes were filled with the formulation and immersed in distilled water. After 24 hours, 7, 14 and 21 days, pH was evaluated. The antimicrobial activity was evaluated against Enterococcus faecalis by agar diffusion test. All data were submitted to ANOVA and Tukey tests (p=0.05). Result: None effect was observed on pH and antimicrobial activity by dentin on different chemical formulations, except the reduction occurred in G1 at 24 hours (p <0.05). When compared between the groups at 24 hours and 7 days, G1A and G1B had a lower pH (p <0.05). At 14 days, G2A, G2B, G3A and G3B showed similar pH (p <0.05) and between G3B and G1A (p> 0.05). At 21 days, all formulations were similar (p> 0.05). Regarding antimicrobial activity G2B G2A => = G3A G3B> = G1A G1B (p <0.05). Conclusion: The dentin did not affect the pH and antimicrobial activity of different formulations containing calcium hydroxide...