Aspects of glass and hybridization protocols for bonding of fiber posts to root dentine.

This study evaluated bond strength of glass fiber posts to root dentin using push-out (PO) and diametral compression (DC), testing glycolic acid as a conditioner and varying dentin moisture. An additional aim was to test whether DC can be an alternative test to PO for bond strength assessment. Eighty bovine teeth were divided into eight groups (n = 10) defined by the use of either 37% glycolic acid or 37% phosphoric acid (PA) on moist or wet dentin before bonding with either Adapter SingleBond/RelyX ARC or One Step Plus/Duo-Link Bisco. Each tooth provided discs with an internal diameter of 2 mm, external diameter of 5 mm, and height of 2 mm, which underwent PO and DC. Finite element analysis (FEA) was carried out on 3D models. When analyzing PO results through linear regression, the highest values of bond strength were observed using glycolic acid on wet dentin in the cervical and middle thirds of the teeth. Analyzing DC results, the only statistical influence on values was the dental thirds. The scatterplot of the DC results and the PO bond strength values indicated no relationship between the results of the two tests (r = 0.03; p = 0.64). PO test detected more sensitive changes in bond strength values than DC.

Antimicrobial action and cytotoxicity of hypochlorous acid obtained from an innovative electrolytic device - An in vitro study.

OBJECTIVE: This study evaluated the antimicrobial effect and cytotoxicity of hypochlorous acid(HClO) obtained from an innovative electrolytic device. DESIGN: The root canals of fifty extracted human teeth were inoculated with Enterococcus faecalis and divided into 5 groups (n = 10): DW (control); 2% chlorhexidine gel(CHX); 2.5% sodium hypochlorite(NaOCl); 250 ppm HClO and 500 ppm HClO. The counting of colony forming units evaluated the decontamination potential of each group. Cytotoxicity was evaluated after inoculation of tested protocols in fibroblastic cells for 3 min, calculating the cell viability. Specific statistical analysis was performed (α = 5%). RESULTS: The highest bacterial reduction was observed in experimental groups, with no statistical differences from each other (p > 0.05). The highest number of viable cells was observed in control group, followed by 250 ppm HClO and 500 ppm HClO groups, with statistical differences from each other (p < 0.05). CONCLUSIONS: It could be concluded that HClO presented high antimicrobial activity and low cytotoxicity at both tested concentrations.

Antimicrobial action, cytotoxicity and erosive potential of hypochlorous acid obtained from an electrolytic device compared with sodium hypochlorite.

OBJECTIVES: This study aimed to compare the antimicrobial action, cytotoxicity, cleaning ability, and erosion of dentine of hypochlorous acid (HClO) obtained from an electrolytic device at two different concentrations (Dentaqua) and three concentrations of sodium hypochlorite (NaOCl). METHODS: Microbiological test-The root canals of sixty single-rooted extracted human teeth were inoculated with Enterococcus faecalis and divided into 6 groups (n = 10), according to decontamination protocol: DW (control); 1% NaOCl; 2.5% NaOCl; 5.25% NaOCl; 250 ppm HClO and 500 ppm HClO. The colony-forming units were counted to evaluate the decontamination potential of each group, calculating the reduction in bacterial percentage. Cytotoxicity test-Cytotoxicity was evaluated after inoculation of the same tested protocols in fibroblastic cells for 3 min, calculating the cell viability percentages. Specifical statistical analysis was performed (α = 5%). Cleaning ability and erosion-Fifty-six single-rooted bovine lower incisors were divided into seven groups of 8 roots each, being the test groups 1% NaOCl; 2.5% NaOCl; 5,25% NaOCl; 250 ppm HClO and 500 ppm HClO, and a negative and positive control. Negative control was not contaminated, and the other groups were inoculated with Enterococcus faecalis. SEM images were ranked as from the cleanest to the least clean. Erosion was also assessed, being ranked from the least to the most eroded dentine. RESULTS: The highest bacterial reduction was observed in experimental groups, with no statistical differences between them (p > 0.05). The highest number of viable cells was observed in control group, followed by 250 ppm HClO and 500 ppm HClO groups, with statistical differences between them (p < 0.05). 1% NaOCl; 2.5% NaOCl; 5.25% NaOCl and 500 ppm HClO displayed the cleanest areas. All sodium hypochlorite groups displayed erosion with higher ranks with greater concentration, while hypochlorous acid did not display any erosion regardless the concentration. CONCLUSIONS: It is possible to conclude that HClO obtained from an electrolytic device presented high antimicrobial activity and low cytotoxicity in both tested concentrations. 500 ppm HClO did not display erosion and showed great cleaning ability. CLINICAL RELEVANCE: The use of 500 ppm hypochlorous acid may reduce unfavorable behavior of sodium hypochlorite whilst maintaining its antimicrobial action.

Maxillofacial infections of dental origin: risk factors for hospital admission

Aim: to evaluate the occurrence of maxillofacial infection cases, which were treated at local hospital, identifying the main risk factors that determine the need for hospitalization of patients and the factors associated with staying length. Methods: A retrospective review of 191 records of patients with maxillofacial infection of odontogenic origin was performed, statistically evaluated by frequency and percentage of involvement, p values (based on the chi-square test) and odds ratio with a 95% confidence interval. A p-value <0.05 was considered statistically significant. Results: Among all the 191 patients, 31 had some harmful habits, such as smokers (13%) and alcoholics (1%). In addition, 39 patients reported some general health problem, such as systemic arterial hypertension (8.3%), depression (6.8%), diabetes (3.6%) and some immunosuppression (1.57%). Involvement of infection in deep facial spaces was present, with 119 patients presenting a deeper infection (62.3%) and 72 patients a superficial infection (37.7%). The most prevalent clinical signs and symptoms in the initial evaluation were pain (91.1%) and edema (90.1%), followed by erythema/hyperemia (44.5%), trismus (37.7%), abscess (30.9%), cellulitis (27.7%), f istula (16.8%), fever (16.8%), dysphagia (11%), dehydration (9.9%), odynophagia (7.9% ) and dyspnea (3.7%). Pulp necrosis was considered a risk factor for treatment in a hospital environment (0.032) and root canal treatment decreases the risk of hospitalization (p=0.002). Considering the evaluated patients, 146 (76.4%) were admitted and 45 (37.7%) were not admitted for hospitalization after initial clinical evaluation. Conclusion: there is a high occurrence of maxillofacial infection cases of dental origin, considering that involvement of infection in deeper facial spaces, as well as presence of pain, edema, erythema/hyperemia, trismus, abscess, cellulitis and pulp necrosis, represent the main risk factors for hospitalization and staying length

The incidence of unfilled second mesiobuccal canals and periapical lesions in maxillary molars by cone-beam computed tomography E-VOL DX software

This study evaluated the incidence of unfilled second mesiobuccal (MB2) canals and periapical lesions in first maxillary molars using CBCT e-Vol DX software. Hence, 326 CBCT images of first maxillary molars of patients undergoing endodontic treatment were selected. The e-Vol DX software performed a retrospective review of these images, recording the presence or absence of MB2 canals, filling, and periapical lesions in first maxillary molars. Specific statistical analysis was performed at a 5% significance level. Unfilled MB2 canals were highly frequent in first maxillary molars and significantly associated with periapical lesions in the mesiobuccal root of these teeth (p<0.05). The CBCT e-Vol DX software effectively detected MB2 canals, and unfilled canals may be associated with periapical lesions.

Does photobiomodulation on the root surface decrease the occurrence of root resorption in reimplanted teeth? A systematic review of animal studies.

This review aimed to answer the following question "Does photobiomodulation treatment of the root surface decrease the occurrence of root resorption in reimplanted teeth?" Electronic searches were performed in the MEDLINE/PubMed, Cochrane Library, Scopus, Web of Science, Embase, and Grey Literature Report databases. Risk of bias was evaluated using SYRCLE Risk of Bias tool. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) tool was used to assess the certainty of evidence. In total, 6 studies were included. Five studies reported a reduced occurrence of root resorption in teeth that received photobiomodulation treatment of the root surface prior to replantation. Only 1 study reported contradictory results. The photobiomodulation parameters varied widely among studies. GRADE assessment showed a low certainty of evidence. It can be inferred that photobiomodulation treatment of the root surface prior to replantation of teeth can reduce the occurrence of root resorption. Nonetheless, further clinical studies are needed. Trial Registration: PROSPERO Identifier: CRD42022349891.

Dentinal tubule penetration of sodium hypochlorite in root canals with and without mechanical preparation and different irrigant activation methods.

Objectives: This study evaluated the dentinal penetration depth of 2.5% sodium hypochlorite (NaOCl) in root canals with and without preparation and different irrigant activation protocols. Materials and Methods: Sixty-three bovine mandibular incisors were randomly allocated to 6 groups (n = 10): G1, preparation + conventional needle irrigation (CNI); G2, preparation + passive ultrasonic irrigation (PUI); G3, preparation + Odous Clean (OC); G4, no preparation + CNI; G5, no preparation + PUI; G6, no preparation + OC; and CG (negative control; n = 3). Samples were filled with crystal violet for 72 hours. Irrigant activation was performed. Samples were sectioned perpendicularly along the long axis, 3 mm and 7 mm from the apex. Images of the root thirds of each block were captured with a stereomicroscope and analyzed with an image analysis software. One-way analysis of variance, followed by the Tukey post hoc test, and the Student's t-test were used for data analysis, with a significance level of 5%. Results: The NaOCl penetration depth was similar when preparation was performed, regardless of the method of irrigation activation (p > 0.05). In the groups without preparation, G6 showed greater NaOCl penetration depth (p < 0.05). The groups without preparation had a greater NaOCl penetration depth than those with preparation (p = 0.0019). Conclusions: The NaOCl penetration depth was similar in groups with root canal preparation. Without root canal preparation, OC allowed deeper NaOCl penetration. The groups without preparation had greater NaOCl penetration than those undergoing root canal preparation.

Effectiveness of ultrasonic activation over glycolic acid on microhardness, cohesive strength, flexural strength, and fracture resistance of the root dentin.

OBJECTIVES: The aim of this study was to evaluate the effectiveness of ultrasonic activation (US) over glycolic acid on microhardness, cohesive strength, flexural strength, and fracture resistance of root dentin, comparing with conventional final irrigation protocols. METHODS: Samples were obtained from 140 extracted bovine teeth and distributed into four test groups: microhardness (50 teeth), cohesive strength (15 teeth), flexural strength (15 teeth), and fracture resistance (60 teeth). In all four tests, specimens were subdivided into five groups, according to final irrigation protocols: G1: distilled water (DW); G2: 17% ethylenediaminetetraacetic acid (EDTA); G3: 17% glycolic acid (GA); G4: 17% EDTA + US; and G5: 17% GA + US. The duration time of each protocol was set in 1 min. After irrigation protocols, the Vickers tester was used to evaluate microhardness and the universal testing machine was used to evaluate the cohesive strength, flexural strength, and fracture resistance of the root dentin. One-way ANOVA test and the Tukey HSD were used for multiple comparison tests in all evaluations (α = 5%). RESULTS: In general, groups 2 (EDTA), 4 (EDTA + US), and 5 (GA + US) promoted the highest reduction of microhardness, being statistically different from other groups (p < 0.05). Cohesive strength, flexural strength, and fracture resistance data revealed that no differences between groups were observed (p > 0.05). CONCLUSIONS: The association of GA and US results in microhardness reduction, with no influence on cohesive strength, flexural strength, and fracture resistance of the root dentin. CLINICAL RELEVANCE: The use of US over GA has no influence on some mechanical properties of root dentin.

Effectiveness of ultrasonic activation associated to glycolic acid on smear layer removal, dentin structure and bond strength to root dentin

This study evaluated the effects of ultrasonic activation (US) associated to glycolic acid (GA) on smear layer, dentin structure and bond strength (BS) of filling/restorative material to root dentin. The roots were used for antimicrobial activity, dentin structure and BS evaluation, being distributed into seven groups, according to irrigation protocols: G1:DW+US; G2:17% EDTA; G3:QMix; G4:17% GA; G5:17% EDTA+US; G6:QMix+US; G7:17% GA+US. Scanning electronic microscopy, transmission electronic microscopy and push-out were performed, with specific statistical analysis for each evaluation. The highest smear layer removal occured in Groups 6 and 7 (p<0.05), and the largest collagen dispersion in Group 7, being similar to Group 2 and 5 (p>0.05). The highest BS of filling and restorative material occurred in Groups 6 and 7, and Groups 5, 6 and 7, respectively, being similars between them (p>0.05). The use of GA+US promoted effective smear layer removal and dentin structure preservation, improving the BS of filling/restorative material to root dentin.

Influence of photodynamic therapy, different final irrigants, and ultrasonic activation on the bond strength of glass fiber posts to root dentin.

OBJECTIVE: To evaluate the influence of photodynamic therapy (PDT), different final irrigants, and ultrasonic activation (US) on the bond strength of glass fiber posts (GFP) to root dentin. METHODS: One hundred twenty bovine roots were divided into 12 groups according to PDT application, the type of final endodontic irrigant, and US. The samples were divided into 12 groups (n = 10): G1-DW(distilled water); G2-DW+US; G3-17% EDTA; G4-17% EDTA+US; G5-17% GA (glycolic acid); G6-17% GA+US; G7-PDT+DW; G8-PDT+DW+US; G9-PDT+17% EDTA; G10-PDT+17% EDTA+US; G11-PDT+17% GA; G12-PDT+17% GA+US. After cementing the glass fiber posts with resin cement, roots were sectioned into 2-mm-thick slices. One slice from the cervical third and another from the middle third were used for the push out test (PO), and the other two for the diametral compression test (DC). Thus, 10 samples were obtained per third for each mechanical test (n = 10). Kruskal-Wallis and Student-Newman-Keuls tests were used to analyze PO and DC data, and Pearson's correlation test was used to verify the relationship between the variables. Failure patterns were analyzed with chi-square test. RESULTS: Significant differences were found in the PO test among the experimental groups (p < 0.001; power=1.00). PDT improved bond strength when using EDTA. PDT and US increased bond strength when using GA. Favorable failure patterns occurred more frequently in Group GA+US. There was no correlation between data obtained with PO and DC tests (r = 0.112; p = 0.729). CONCLUSION: PDT provided the highest bond strength values of GFP to root dentin when associated with GA and US or when associated only with EDTA.

Effect of bioceramic root canal sealers on the bond strength of fiber posts cemented with resin cements.

This study aimed to evaluate the influence of calcium silicate-based sealers on the bond strength of fiber posts using conventional and self-adhesive resin cement. Sixty single-rooted teeth were selected. The canals were prepared with a reciprocating instrument 40.06. The roots were randomly distributed in six groups (n = 10) according to the strategies for root canal filling and fiber posts cementation: AH Plus/RelyX ARC; AH Plus/RelyX U200; Bio C Sealer/RelyX ARC; Bio C Sealer/RealyX U200; Sealer Plus BC/RelyX ARC; and Sealer Plus BC/RelyX U200. The roots were transversally sectioned, and one slice per post-third was obtained. The push-out test was performed at a crosshead speed of 1mm/min. The failure patterns were described after assessment with a stereomicroscope with a 10× magnification. Bond strength was calculated and analyzed using the ANOVA and Tukey test. AH Plus did not influence the bond strength of fiber posts cemented with conventional (RelyX ARC) or with self-adhesive resin cement (RelyX U200). The lowest bond strength values were obtained when calcium silicate-based sealers were associated with conventional resin cement (Bio C Sealer/RelyX ARC and Sealer Plus BC/RelyX ARC). Except for Sealer Plus BC/RelyX ARC, all groups presented lower bond strength at the apical portion compared to the cervical portion of the post. Adhesive failures between cement and post and cement and dentin were predominant (55.3%). Calcium silicate-based sealers decreased the bond strength of fiber posts cemented with conventional resin cement.

Effect of bioceramic root canal sealers on the bond strength of fiber posts cemented with resin cements

Abstract This study aimed to evaluate the influence of calcium silicate-based sealers on the bond strength of fiber posts using conventional and self-adhesive resin cement. Sixty single-rooted teeth were selected. The canals were prepared with a reciprocating instrument 40.06. The roots were randomly distributed in six groups (n = 10) according to the strategies for root canal filling and fiber posts cementation: AH Plus/RelyX ARC; AH Plus/RelyX U200; Bio C Sealer/RelyX ARC; Bio C Sealer/RealyX U200; Sealer Plus BC/RelyX ARC; and Sealer Plus BC/RelyX U200. The roots were transversally sectioned, and one slice per post-third was obtained. The push-out test was performed at a crosshead speed of 1mm/min. The failure patterns were described after assessment with a stereomicroscope with a 10× magnification. Bond strength was calculated and analyzed using the ANOVA and Tukey test. AH Plus did not influence the bond strength of fiber posts cemented with conventional (RelyX ARC) or with self-adhesive resin cement (RelyX U200). The lowest bond strength values were obtained when calcium silicate-based sealers were associated with conventional resin cement (Bio C Sealer/RelyX ARC and Sealer Plus BC/RelyX ARC). Except for Sealer Plus BC/RelyX ARC, all groups presented lower bond strength at the apical portion compared to the cervical portion of the post. Adhesive failures between cement and post and cement and dentin were predominant (55.3%). Calcium silicate-based sealers decreased the bond strength of fiber posts cemented with conventional resin cement.

Resumo Este estudo teve como objetivo avaliar a influência de cimentos à base de silicato de cálcio na resistência de união de pinos de fibra utilizando cimentos resinosos convencionais e autoadesivos. Sessenta dentes humanos monorradiculares foram selecionados. Os canais foram preparados um instrumento reciprocante 40.06. As raízes foram distribuídas aleatoriamente em seis grupos (n = 10) de acordo com as estratégias de obturação do canal e cimentação dos pinos de fibra: AH Plus/RelyX ARC; AH Plus/RelyX U200; Bio C Sealer/RelyX ARC; Bio C Sealer/RealyX U200; Sealer Plus BC/RelyX ARC; e Sealer Plus BC/RelyX U200. As raízes foram seccionadas transversalmente e foi obtido um espécime por terço. O teste de push-out foi realizado em uma velocidade de 1mm/min. Os padrões de falha foram descritos após avaliação em estereomicroscópio com aumento de 10×. A resistência de união foi calculada e analisada por ANOVA e teste de Tukey. AH Plus não influenciou na resistência de união dos pinos de fibra cimentados com cimento resinoso convencional (RelyX ARC) ou autoadesivo (RelyX U200) (p > 0,05). Os menores valores de resistência de união foram obtidos quando os cimentos à base de silicato de cálcio foram associados ao cimento resinoso convencional (Bio C Sealer/RelyX ARC e Sealer Plus BC/RelyX ARC) (p < 0,05). Com exceção do Sealer Plus BC/RelyX ARC, todos os grupos apresentaram menor resistência de união na porção apical em comparação com a porção cervical do pino (p < 0,05). Falhas adesivas entre cimento e pino e cimento e dentina foram predominantes (55,3%). Cimentos a base de silicato de cálcio diminuíram a resistência de união de pinos de fibra cimentados com cimento resinoso convencional.

Effect of glycolic acid and EDTA on dentin mechanical properties.

The aim of this study was to evaluate the effect of glycolic acid (GA) and EDTA on dentin mechanical properties. For the cohesive strength, flexural strength and fracture strength tests, the hourglass of root dentin, dentin sticks and roots standardised to 1 mm thickness were used respectively. ANOVA and Tukey tests were used for statistical analysis (P < 0.05). The results showed that EDTA and GA 17% reduced the cohesive strength values when compared to distilled water (control; P = 0.0022 and P = 0.0016 respectively), whereas the values for GA 10% group were similar to those of the control group (P = 0.093). No statistically significant difference was found among the groups for the flexural strength test (P = 0.1974). Fracture strength test showed that EDTA and GA 17% were statistically similar to each other (P = 0.7694) and statistically inferior to GA 10% (P = 0.0007 and P = 0.0004 respectively). It was concluded that 10% GA showed fewer negative effects on dentin mechanical properties.

Oral bacterial decontamination using an innovative prototype for photocatalytic disinfection.

OBJECTIVES: The aim of this study was to evaluate the effectiveness of a prototype photocatalytic device for bacterial decontaminations of the oral cavity. METHODS: Sixty-four subjects (18-65) were selected and randomly assigned to eight groups (n = 8), according to oral disinfection protocol: (G1): distilled water (control); (G2): 1.5% hydrogen peroxide (HP); (G3): 3.0% HP; (G4): 0.12% chlorhexidine (CHX); (G5): Germinator; (G6): 1.5% HP + Germinator; (G7): 3.0%HP + Germinator; (G8): 0.12% CHX + Germinator. Stimulated saliva was collected before and after a 3-min mouthwash and/or Germinator application. The patients were kept relaxed and retained saliva 5-10 min, spitting out into the tube for 3 min. The percentage bacterial reduction was checked by counting the colony-forming units (CFUs) after culturing on blood agar plates. Data were subjected to one-way ANOVA followed by Tukey's post hoc test (α = 5%) for statistical significance. RESULTS: The highest bacterial reduction was observed in groups 3 (3.0% HP), 6 (1.5% HP + Germinator), and 7 (3.0% + Germinator), with no statistically significant difference between them (p > 0.05). Groups 6 (1.5% HP + Germinator) and 8 (0.12% CHX + Germinator) showed higher bacterial reduction than groups 2 (1.5% HP) and 4 (0.12% CHX) (p < 0.05). Finally, group 5 (Germinator) showed higher bacterial reduction than control group (DW) and group 4 (0.12% CHX) (p < 0.05). CONCLUSIONS: The photocatalytic disinfection was effective against oral bacteria and improved the antimicrobial action of 1.5% HP and 0.12%. CLINICAL SIGNIFICANCE: The photocatalytic disinfection can be an alternative protocol to provide the oral decontamination.

Analysis of different platelet-rich fibrin processing / Análise de diferentes processamentos da fibrina rica em plaquetas

Introduction: Platelet-rich fibrin (PRF) is formed by an autologous blood concentrate, with properties that promote cell proliferation and regenerationof bone, gingival and epithelial tissue. Objective: To compare four different procedures for processing as well as obtaining PRF, and analyzing their formation through laboratory techniques. The purpose of the study is to validate a method that produces higher quality PRF for oral surgery use in different branches of dentistry. Material and method: The experiment consisted of collecting blood from 12 volunteers, and processing each patient's sample in 4 different ways. In the following two-stage process analysis, the first, quantitative, step was to analyze the samples' platelet-poor plasma (PPP),with a Neubauer Hemocytometer to count blood components. In the second, qualitative step, the sample's PRF were analyzed under microscopy using histological slides. Result: The statistical analysis of the leukocyte, red blood cell and platelet count did not show any significant distinction when comparing different processes. Histological analysis of the PRF showed fibrin network with platelet aggregation, several leukocytes and presence of red blood cells, with double centrifuged samples presenting more white blood cells than the others. Conclusion: Among the analyzed procedures, the sample centrifuged once at 3000 RPM (1900 G) for 10 min showed the best quality PRF.

Introdução: A fibrina rica em plaquetas (FRP) é formada por um concentrado sanguíneo autólogo, com propriedades de promover a proliferação celular, regeneração de tecido, dentre eles tecido ósseo, gengival e epitelial. Objetivo: Comparar quatro tipos diferentes de processamento e obtenção de FRP, analisando a sua formação através de técnicas laboratoriais. A finalidade do estudo é validar um método que obtenha maior qualidade para o uso em cirurgias nas diversas áreas da odontologia. Material e método: O experimento foi constituído de uma coleta de sangue de 12 voluntários, onde a amostra de cada paciente foi processada de 4 formas. A análise dos processamentos se deu em duas etapas, onde na primeira, quantitativa, foi analisado o plasma pobre em plaquetas (PPP), através de contagem de constituintes sanguíneos em câmara de Neubauer. Na segunda etapa, qualitativa, foram analisadas as FRP em microscopia através de lâminas histológicas. Resultado: A análise estatística da contagem de leucócitos, hemácias e plaquetas não mostraram diferença significativa entre os distintos processamentos. As análises histológicas do FRP mostraram redes de fibrina com agregação plaquetária, inúmeros leucócitos e presença de hemácias, sendo que as amostras de dupla centrifugação apresentaram mais leucócitos que nas demais. Conclusão: Dos procedimentos analisados, a amostra centrifugada a 1 única vez a 3000 RPM (1900 G) por 10 min mostrou-se a melhor qualidade de FRP.

Avaliação do nível de sujidade de sistemas rotatório e reciprocante após instrumentação e procedimentos de limpeza pré-esterilização / Evaluation of the dirt level of rotary and reciprocating systems after instrumentation and pre-sterilization cleaning procedures

Objetivos: avaliar a sujidade de limas rotatórias e reciprocantes após instrumentação e procedimentos de limpeza pré-esterilização. Materiais e métodos: 24 limas rotatórias e as 24 limas reciprocantes foram divididas, aleatoriamente, em dois grandes grupos. No primeiro grupo, as 12 limas rotatórias e as 12 limas reciprocantes foram divididas, aleatoriamente, em seis subgrupos (SG): SG1 (controle negativo 1/n=1) ­ 1 lima rotatória não submetida à instrumentação; SG2 (controle negativo 2/n=1) ­ 1 lima reciprocante não submetida à instrumentação; SG3 (controle positivo 1/n=1) ­ 1 lima rotatória submetida à instrumentação e não submetida a qualquer protocolo de limpeza; SG4 (controle positivo 2/n=1) ­ 1 lima reciprocante submetida à instrumentação e não submetida a qualquer protocolo de limpeza; SG5 (grupo teste/n=10) ­ 10 limas rotatórias submetidas à instrumentação e submetidas ao protocolo de lavagem manual; SG6 (grupo teste/ n=10) ­ 10 limas reciprocantes submetidas à instrumentação e submetidas ao protocolo de lavagem manual. No segundo grupo, as 12 limas rotatórias e as 12 limas reciprocantes foram divididas, aleatoriamente, nos mesmos subgrupos, substituindo, nos subgrupos 5 e 6, a lavagem manual pela lavagem em cuba ultrassônica. A análise do nível de sujidade foi realizada por microscopia eletrônica de varredura (MEV), sendo os dados submetidos ao teste de Kruskal-Wallis, com nível de significância de 5%. Resultados: a menor média de sujidade entre os grupos experimentais foi encontrada no SG5 do G1, sem diferença significante em relação aos demais grupos testados (p>0,05). Conclusão: conclui-se que os protocolos de limpeza testados não foram completamente efetivos para a remoção de sujidade das limas endodônticas.(AU)

Objective: to evaluate the dirt of rotary and reciprocating files after instrumentation and pre- -sterilization cleaning procedures. Materials and Methods: 24 rotary files and the 24 reciprocating files were randomly divided into two groups. In the 1st group, 12 rotary files and 12 reciprocating files were randomly divided into six subgroups (SG): SG1 (negative control 1/n=1) ­ 1 rotary file not subjected to instrumentation; SG2 (negative control 2/n=1) ­ 1 reciprocating file not subjected to instrumentation; SG3 (positive control 1/n=1) ­ 1 rotary file submitted to instrumentation and not submitted to any cleaning protocol; SG4 (positive control 2/n=1) ­ 1 reciprocating file submitted to instrumentation and not submitted to any cleaning protocol; SG5 (test group/n=10) ­ 10 rotary files submitted to instrumentation and submitted to the manual cleaning protocol; SG6 (test group/n=10) ­ 10 reciprocating files submitted to instrumentation and submitted to the manual cleaning protocol. In the 2nd group, the 12 rotary files and the 12 reciprocating files were randomly divided into the same subgroups, substituting, in subgroups 5 and 6, manual with ultrasonic bath cleaning. The analysis of dirt levels was performed by scanning electron microscopy (SEM), being the data submitted to the Kruskal-Wallis test, with a significance level of 5%. Results: the lowest average of dirt between the experimental groups was found in SG5 of G1, with no significant difference when compared to the other groups (p>0.05). Conclusion: it could be concluded that the cleaning protocols were not completely effective in removing dirt from endodontic files.(AU)

Influence of ultrasonic activation on antimicrobial activity of a new final irrigant containing glycolic acid: An in vitro study.

This study evaluated the influence of ultrasonic activation (US) on the antimicrobial activity of a new final irrigant containing glycolic acid (GA). Extracted teeth were used, being 70 to counting of colony-forming units (CFUs) and 35 to confocal laser scanning microscopy. Samples were inoculated with Enterococcus faecalis and divided into 7 groups: distilled water + US; 17% EDTA; Qmix; 17% GA; 17% EDTA + US; QMix + US; and 17% GA + US and kept in contact with test solution for 1 min in the groups with or no US. In the CFUs, the highest bacterial reduction was observed in QMix + US group, followed by QMix and GA + US. In the confocal evaluation, the lowest number of viable cells was observed in EDTA + US, with no statistical difference from QMix, QMix + US and GA + US (P > 0.05). The use of US improves the antimicrobial activity of EDTA and GA, being statistically different from the isolated use of these final irrigants in both evaluation tests.

Evaluation of apical transportation and apical root sealing in root canals prepared with mtwo rotary system with and without apical enlargement ­ an in vitro study

The aim of this study was to evaluate apical transportation and apical root canal sealing after root canal filling in human teeth prepared with MTwo® Rotary System with and without apical foramen enlargement. Twenty mandibular premolars were divided into two groups (n=10). Group 1 had root canals prepared 1mm beyond the apical foramen. Group 2 had root canals prepared 1mm below the root canal length. After chemo-mechanical preparation, samples were submitted to scanning electronic microscopy. Apical foramen images had 75x magnification at standardized positions, allowing measurements from the apical foramen area before and after root canal preparation, and after root canal filling. Apical foramen shape and apical transportation, as well as its level of circumferential filling after root canal preparation were accessed using the Image Subtraction System. Scanning electronic microscopy analysis demonstrated that samples of Group 1 showed larger foraminal diameter than samples of Group 2 (p<0.05). Apical foramen transportation was statistically different between Groups 1 and 2 (p=0.0108). Furthermore, the apical foramen sealing also differed statistically between groups 1 and 2 (p=0.0007) and 100% of samples of Group 1 showed apical root canal sealing. Apical root canal sealing was more effective when the root canal was prepared with apical foramen enlargement, even when the apical transportation was detected.

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.