Impact of Calcium-Hydroxide, Sodium Ascorbate, and Sodium Thiosulphate on Bond Strength of Composite Restorations to Bleached Dentin.

This study evaluated the impact of using calcium-hydroxide or the antioxidant agents on the bond strength of adhesive restorations to bleached dentin. Forty teeth were prepared and allocated into 8 groups according to the surface treatment after bleaching (application or not of calcium hydroxide, 10% sodium ascorbate and 5% sodium thiosulphate for 10min), and the time of final restoration (immediate or after 7-days). Sodium perborate with 20% hydrogen peroxide was applied for 3 weeks using a developed artificial pulp chamber, with replacement every week. Composite resin restoration was performed and microtensile test was performed. Then, specimens were analyzed using a stereomicroscope and SEM. Data was submitted to Kruskal-Wallis and Dunn tests (p<0.05). The bond strength of non-bleached teeth was similar to the groups restored after 7 days of bleaching (p<0.05). The lowest values of bond strength were showed by groups restored immediately after bleaching (p<0.05). In all groups, there was a considerable predominance of adhesive fractures. Delaying the final restoration of teeth submitted to nonvital bleaching for 7 days permits an increase in bond strength. The immediate restoration of bleached teeth after the use of 10% sodium ascorbate or 5% sodium thiosulfate for 10 minutes showed unsatisfactory results. Clinical relevance Irrespective of the dentin protocol applied before adhesion, a satisfactory and an unsatisfactory result of bond strength values will be obtained delaying the final restoration or immediately performing the final restoration, respectively. Therefore, after nonvital tooth bleaching, clinicians should always delay the final restoration for a minimum period of 7 days.

Impact of Minimally Invasive Endodontic Procedures on the Development of Dentinal Microcracks.

INTRODUCTION: To evaluate the impact of root canal preparation in teeth with ultraconservative access cavities (UltraAC) on the development of dentinal microcracks using a nondestructive longitudinal micro-computed tomography (micro-CT) imaging experimental model. Root canal preparation in teeth with traditional access cavities (TradAC) was used as control. METHODS: Forty mandibular molars were scanned in a micro-CT device, anatomically matched, and distributed into 4 groups according to the type of access cavity and instrumentation system: traditional/Reciproc (TradAC/RC), traditional/XP-endo Shaper (TradAC/XP), ultraconservative/Reciproc (UltraAC/RC), and ultraconservative/XP-endo Shaper (UltraAC/XP). After root canal preparation, the teeth were rescanned. After reconstruction and co-registration procedures, the images were screened from the furcation level to the apex to identify the presence of dentinal microcracks. RESULTS: From a total of 15,340 cross-section images, 19.65% (3014 slices) had some dentinal microcracks. The qualitative analysis demonstrated the presence of some dentinal microcracks in 11%, 33%, 19%, and 15% of the images of cross-sections in TradAC/RC, TradAC/XP, UltraAC/RC, and UltraAC/XP groups, respectively. All dentinal microcracks observed after root canal preparation were already present in the corresponding images before canal instrumentation. Therefore, no new microcracks were detected, regardless of the access cavity and root canal instrumentation system. CONCLUSIONS: Root canal preparation with Reciproc or XP-endo Shaper under traditional or ultraconservative access cavities did not create dentinal microcracks in extracted mandibular molars.

The Impact of TruNatomy and ProTaper Gold Instruments on the Preservation of the Periradicular Dentin and on the Enlargement of the Apical Canal of Mandibular Molars.

INTRODUCTION: This study aimed to evaluate the preservation of periradicular dentin and the enlargement of the apical canal of mandibular molars with TruNatomy (Dentsply Sirona, Ballaigues, Switzerland) and ProTaper Gold (Dentsply Sirona) instruments. METHODS: Twenty mandibular molars were scanned in a micro-computed tomographic device, anatomically paired, and distributed into 2 groups (n = 10). In the ProTaper Gold group, mesial and distal canals were prepared up to F2 (25/.08v) and F3 (30/.09v) instruments, whereas in the TruNatomy group, mesial and distal canals were enlarged up to the prime (26/.04v) and medium (36/.03v) instruments, respectively. After a new scan, the surface area, volume, unprepared areas, transportation, percentage of dentin removal, and dentin thickness parameters were calculated. Data were compared between groups using the Mann-Whitney test, the Student t test, and the nonmetric multidimensional scaling test with alpha set at 5%. RESULTS: No difference was found between groups regarding unprepared canal areas and the reduction of dentin thickness (P > .05). Transportation was lower than 0.1 mm in all groups, and statistical differences were observed only at the apical third of the mesiobuccal canal with lower values in the TruNatomy group. ProTaper Gold removed more dentin than TruNatomy at the coronal level of mesial roots (1.8% and 1.0%, respectively) (P < .05). CONCLUSIONS: TruNatomy and ProTaper Gold were efficient for performing canal preparation in mandibular molars. The tested systems were similar in terms of untouched canal walls and remaining dentin thickness and slightly different in the apical transportation of mesial canals and the percentage of dentin removal at the coronal third but without clinically significant errors.

Effect of passive ultrasonic irrigation on hard tissue debris removal: a systematic review and meta-analysis.

Accumulated hard tissue debris (AHTD) in root canal irregularities may negatively impact adequate root canal disinfection. In light of this, the efficacy of passive ultrasonic irrigation (PUI) to reduce AHTD has been largely studied in in vitro studies, which have adopted different analytic methods of varying accuracy to determine the extent of AHTD more correctly. Therefore, the aim of this study was to compare how well PUI and non-activated irrigation (NAI) systems perform in reducing AHTD during final irrigation protocols, based exclusively on studies whose analyses used microCT scanning. A systematic search of the studies published up to April 2020 was performed using MeSH terms and free terms, in the following databases: PubMed, Scopus, Web of Science, BVS (Lilacs and BBO) and Embase. The inclusion criteria consisted of laboratory studies that evaluated the amount of AHTD, and compared PUI with NAI protocols using microCT analysis. The risk of bias in the selected studies was assessed critically by two reviewers. A meta-analysis was performed using the RevMan software program (P<0.05), and included studies providing the standardized mean difference (SMD), using a fixed effect model, and adopting a confidence interval of 95%. In all, 3495 studies were identified, three of which met the inclusion criteria. All three were considered as having a low risk of bias. The meta-analysis comparing the ability of PUI and NAI protocols to remove hard tissue debris showed a higher percentage of AHTD reduction (P<0.01) for PUI, with a confidence interval of 1.41 [0.79, 2.02]. The heterogeneity among the studies was 82% (I2). Considering the limitations of the present study, this systematic review and meta-analysis showed that PUI was more effective than NAI in removing hard tissue debris, based exclusively on studies that used microCT scanning to provide a more precise analysis of the two techniques used. The findings presented in the present study reinforce the concept that PUI can increase residue removal and improve the cleanliness of the root canal in endodontic treatments.

Influência do pré-alargamento coronário na resistência à fadiga cíclica de instrumentos reciprocantes tratados termicamente / Influence of coronal pre-enlargement on cyclic fatigue resistance of heat-treated reciprocating instruments

Objetivo: O objetivo do presente estudo foi avaliar a influência do pré-alargamento coronário na resistência à fadiga cíclica de dois instrumentos reciprocantes tratados termicamente. Métodos: 20 instrumentos Reciproc Blue (R25 Blue) e 20 instrumentos X1 Blue (X1) foram utilizados para instrumentar blocos de resina simulando um molar superior com três canais radiculares. Os dentes foram divididos em quatro grupos (n=10), de acordo com o instrumento e com a técnica de instrumentação utilizada: grupos R25 e X1 - instrumentação com R25 Blue (25/0.08) ou X1 Blue (25/0.06), respectivamente, sem alargamento prévio; e grupos R25 ou X1 + pré-alargamento cervical - pré-alargamento com os instrumentos ProTaper Universal SX e S1 antes da instrumentação com R25 Blue ou X1. Os instrumentos foram testados com relação à fadiga cíclica utilizando-se um canal simulado de aço inoxidável com ângulo de curvatura de 86 graus e raio de curvatura de 6 mm. Os instrumentos foram acionados utilizando-se o movimento "RECIPROC ALL" do motor endodôntico (VDW) e o tempo de instrumentação até a fratura do instrumento foi contabilizado. Os resultados foram analisados pelo teste t de Student (p<0,05). Resultados: Os instrumentos X1 apresentaram maior resistência à fadiga cíclica do que R25 Blue em ambas as condições testadas (p<0,05). Não houve diferença entre os grupos com e sem pré-alargamento coronário para os instrumentos R25 Blue e X1 (p>0,05). Conclusão: O instrumento X1 Blue apresentou maior resistência à fadiga cíclica do que o Reciproc Blue. O pré-alargamento coronário não foi capaz de aumentar a resistência à fratura por fadiga cíclica dos instrumentos testados (AU).

Objective: The aim of this study was to evaluate the influence of cervical pre-flaring on the cyclic fatigue resistance of two heat-treated reciprocating instruments. Methods: 20 Reciproc Blue (R25 Blue) instruments e 20 X1 Blue File (X1) were used to instrument resin blocks simulating an upper molar with 3 root canals. The specimens were divided into four groups (n=10) according the instrument and type of instrumentation used: R25 and X1 groups: root canal preparation with R25 Blue (25/0.08) ou X1 Blue (25/0.06), without cervical pre-flaring; R25 or X1 + cervical pre-flaring- pre-flaring with ProTaper Universal SX e S1 before instrumentation with R25 Blue or X1 blue. After instrumentation the instruments were tested for cyclic fatigue using a simulated stainless steel root canal with 86 degree bending angle and 6 mm bending radius. The instruments were triggered using the "RECIPROC ALL" motion of a reciprocating endodontic motor (VDW) and the instrumentation time until instrument fracture was accounted. Results were analyzed by Students t-test (p<0.05). Results: Statistical analysis showed that the X1 Blue showed higher resistance to cyclic fatigue than the R25 Blue under both conditions tested (p<0.05). There were no differences between the groups with and without coronary pre-flaring for the R25 Blue and X1 Blue (p<0.05). Conclusion: X1 Blue showed higher resistance to cyclic fatigue than the R25 Blue. The cervical pre-flaring did not increased the resistance to cyclic fatigue fracture of the tested instruments (AU)

Acessos endodônticos: o que todo endodontista deve saber / Endodontic accesses: what every endodontist should know

Introdução: Os acessos endodônticos minimamente invasivos (AEMI) surgiram com o intuito de, por meio da preservação de estrutura dentária, manter a resistência à fratura de dentes tratados endodonticamente. A partir do primeiro estudo, em 2010, vários trabalhos foram desenvolvidos buscando entender qual a influência dos AEMI na resistência à fratura de dentes tratados endodonticamente. No entanto, interferências coronárias causadas pelos AEMI poderiam prejudicar a realização dos procedimentos subsequentes à cavidade de acesso, como a localização, instrumentação, limpeza, descontaminação e obturação dos canais radiculares. Objetivo: Com base nessa premissa, a presente revisão teve como objetivo responder algumas perguntas para que o clínico entenda quais são as principais modalidades de AEMI, os impactos da sua abordagem no tratamento endodôntico e o verdadeiro papel do tratamento endodôntico na perda dos elementos dentários. Resultados: Considerando os dados disponíveis até o presente momento, faltam evidências robustas para apoiar a alegação de que os AEMIs preservem a resistência à fratura dos elementos tratados endodonticamente melhor do que nos dentes acessados de maneira tradicional. Além disso, cavidades de acesso minimamente invasivas podem interferir em outras etapas do tratamento endodôntico, podendo torná-lo imprevisível. Conclusão: Dessa forma, pode-se concluir que há uma falta de evidências que apoiem a utilização de cavidades de acesso minimamente invasivas na prática clínica de rotina e/ou no processo de formação de alunos de graduação e pós-graduação (AU).

Introduction: Minimally invasive access cavities emerged aiming to maintain the fracture resistance of endodontically treated teeth through the preservation of dental structure. Starting with the first study in 2010, several others were developed to evaluate the influence of minimally invasive access cavities in the fracture resistance of endodontically treated teeth. However, the coronal interference caused by those access cavities could impair the subsequent procedures of root canal treatment, such as the location, instrumentation, cleaning, disinfection and filling of the root canals. Objective: Based on this premise, the aim of the present review was to answer some questions so that the clinician knows the main modalities of minimally invasive access cavities, the impacts of this approach and the real role of endodontic treatment in the tooth loss. Results: Considering the available data, there is a lack of robust evidence in literature to support the claim that the minimally invasive access cavities preserve the fracture resistance of endodontically treated teeth better than the traditional one. In addition, these access cavities can interfere in other stages of endodontic treatment, making it unpredictable. Conclusion: Thus, it can be concluded that there is a lack of evidence to support the use of minimally invasive access cavities in routine clinical practice and/or in the process of training undergraduate and graduate students (AU).

O uso da tomografia computadorizada de feixe cônico no diagnóstico e no gerenciamento de insucesso endodôntico: relato de caso clínico / The use of cone beam computed tomography in the diagnosis and management of endodontic failure: clinical case report

Objetivo: descrever um caso clínico em que a tomografia computadorizada de feixe cônico (TCFC) foi utilizada para auxiliar no diagnóstico e no melhor gerenciamento de retratamento endodôntico. Relato de caso: uma paciente compareceu à clínica com queixa de uma fístula na região dos molares superiores do lado direito há aproximadamente dois meses. Radiograficamente, observou-se lesão periapical do elemento 17. Após a confirmação da necessidade do retratamento, a paciente relatou já ter feito duas intervenções endodônticas nesse elemento. Assim, optou-se por solicitar um exame de TCFC, para melhores diagnóstico e planejamento do caso. Ao avaliar a TCFC, verificou-se presença de lesão periapical extensa, presença de espaços vazios no canal mesiovestibular (MV) e palatino (P), cone de guta percha além do ápice no canal distovestibular (DV) e localização do canal mesiopalatino (MP), que não havia sido manuseado anteriormente, rompimento de cortical óssea vestibular e palatino. Após planejamento, a paciente foi submetida ao retratamento endodôntico. Foi realizada a desobstrução dos canais radiculares com remoção do cone ultrapassando no canal DV, localização do MP e instrumentação completa de todos os canais. O hidróxido de cálcio foi utilizado como medicamento intracanal entre as consultas. Ao observar a regressão da fistula e os canais sem presença de exsudato, realizou-se a obturação do canal radicular. Considerações finais: a TCFC permitiu a visualização de erros operatórios pertinentes ao caso durante os tratamentos endodônticos prévios, o que possibilitou a indicação de um novo tratamento endodôntico e a manutenção do dente na arcada dentária.(AU)

Objective: to describe a clinical case where cone beam computed tomography (CBCT) was used to assist in the diagnosis and better management of endodontic retreatment. Case report: the patient attended the clinic complaining of a fistula in the upper molar region on the right side for approximately two months. Radiographically, the presence of a periapical lesion of element 17 was observed. After confirming the need for retreatment, the patient reported having already undergone two endodontic interventions on this tooth. Thus, it was decided to request a CBCT exam for better diagnosis and case planning. When assessing the CBCT, there was the presence of extensive periapical lesion, presence of empty spaces in the mesiobuccal (MB) and palatal (P) canal, gutta percha cone beyond the apex in the distobuccal (DB) canal and location of the mesiopalatal (MP) canal - which had not been previously handled -, rupture of the cortex vestibular and palatal bone. After planning, the patient underwent endodontic retreatment. Then, all the previous filling material were removed, including the gutta-percha by passing into the DB canal, MP was localized and complete instrumentation of all root canals were done. Calcium hydroxide was used as an intracanal medication between appointments. When the regression of the fistula was observed and canals were without exudate, root canal filling was performed. Final considerations: the CBCT allowed the visualization of operative errors pertinent to the case during previous endodontic treatments, which allowed the indication of a new endodontic treatment and the maintenance of the tooth in the dental arch.(AU)

Estratégias minimamente invasivas de acesso e preparo e os diferentes desfechos na terapia endodôntica / Minimally invasive access and root canal preparation strategies and the different outcomes in endodontic therapy

As cavidades de acesso dominaram a recente discussão sobre a Endodontia minimamente invasiva (EMI). No entanto, a rotulagem da EMI é mais ampla, envolvendo o uso de instrumentos com conicidades reduzidas ou geometrias inovadoras que permitam a remoção mínima de dentina. Além disso, aprimoramentos metodológicos têm sido sugeridos para mimetizar condições clínicas. Buscando responder algumas questões acerca da EMI, a presente tese é dividida em dois estudos. O estudo 1 avaliou a influência do acesso ultraconservador (UltraAC) na instrumentação, na qualidade da obturação e na capacidade máxima de carga para fratura em molares inferiores após o preparo do canal com o sistema XP-endo Shaper (XP) ou Reciproc (RC) em condições clínicas simuladas. Para isso, quarenta molares inferiores foram microtomografados e pareados em quatro grupos (n = 10), de acordo com o acesso e a instrumentação: TradAC/RC, TradAC/XP, UltraAC/RC e UltraAC/XP. Os dentes foram reescaneados e os parâmetros da instrumentação e obturação foram analisados. Os dentes foram restaurados e submetidos à ciclagem termomecânica e à capacidade máxima de carga para a fratura. O teste ANOVA foi usado para a análise estatística (P < 0,05). Os grupos TradAC apresentaram menor porcentagem (%) de área não preparada do que os grupos UltraAC (P < 0,05). O grupo UltraAC/XP apresentou a menor % de dentina removida (P < 0,05). A % de debris foi menor nos grupos UltraAC/XP e TradAC/XP do que no UltraAC/RC e TradAC/RC (P < 0,05). Os grupos UltraAC demonstraram maior % de espaços vazios e de material obturador na câmara pulpar (P < 0,05). Não houve diferença na capacidade máxima de carga para a fratura entre os grupos (P > 0,05). O estudo 2 avaliou o uso de instrumentos com conicidade reduzida - Bassi Logic ,03 (BL), com diferentes designs (XP) e como grupo de comparação o sistem Reciproc, na eficácia da instrumentação dos canais em condições clínicas simuladas. Vinte e quatro molares foram microtomografados, acessados de forma tradicional e divididos em três grupos (n = 8), de acordo com o preparo: BL, XP e RC. Nos grupos BL e RC, os canais mesiais foram instrumentados com 25/,03 ou R25 e o canal distal com 25/,03 e 40/,03 ou R25 e R40, respectivamente. No grupo XP, o mesmo instrumento foi utilizado em todos os canais (30/,04). Após o preparo, os dentes foram reescaneados e a % de área não preparada e de dentina removida foram avaliadas separadamente para os canais mesiais e distal. Os dados foram analisados com os testes ANOVA e de Tukey (P < 0,05). Verificou-se que o grupo BL apresentou maior % de área não preparada para ambos os canais em relação aos grupos XP e RC (P < 0,05). No entanto, não houve diferença na % de dentina removida entre os grupos (P > 0,05). Com base nos estudos, conclui-se que as estratégias minimamente invasivas adotadas no acesso e na instrumentação foram desvantajosas frente a tratamentos tradicionais, não justificando o seu uso(AU)

Access cavities have dominated the recent discussion on minimally invasive Endodontics (EMI). However, the issue of MIE is broader than access cavities, such as the use of instruments with reduced taper or innovative geometries that allow minimal dentin removal. Furthermore, methodological improvements have been suggested to mimic clinical conditions. Seeking to answer some questions about EMI, this thesis is divided into two studies. The first study evaluated the influence of ultraconservative access (UltraAC) on canal shaping, filling ability and maximum load capacity for fracture of mandibular molars after root canal preparation with XP-endo Shaper (XP) or Reciproc (RC), under simulated clinical conditions. Thus, forty mandibular molars were scanned and paired into four groups (n = 10), according to access and instrumentation protocol: TradAC/RC, TradAC/XP, UltraAC/RC and UltraAC/XP. Teeth were rescanned and the instrumentation and filling parameters were analyzed. The teeth were restored and submitted to thermomechanical cycling and maximum load capacity for the fracture. ANOVA test was used for statistical analysis (P < 0.05). The TradAC groups had a lower percentage (%) of unprepared area than the UltraAC groups (P < 0.05). The UltraAC/XP group had the lowest % of dentin removed (P < 0.05). The % of debris was lower in the UltraAC/XP and TradAC/XP groups than in the UltraAC/RC and TradAC/RC groups (P < 0.05). The highest % of voids and filling material in the pulp chamber was observed in the UltraAC groups (P < 0.05). There was no difference in the maximum load capacity for the fracture between the groups (P > 0.05). The second study evaluated the use of a reduced taper endodontic instrument system - Bassi Logic .03 taper (BL), expandable heat-treated system (XP) and, as comparison, the Reciproc system, on the ability to shape canals under simulated clinical conditions. For that, twenty-four mandibular molars were scanned and divided into three groups (n = 8), according to root canal instrumentation system: BL, XP and RC. In the BL and RC groups, the mesial canals were instrumented with 25/.03 or R25 and the distal canal with 25/.03 and 40/.03 or R25 and R40, respectively. In the XP group, the same instrument was used in all root canals (30/.04). After preparation, the teeth were rescanned and the % of unprepared area and dentin removed were evaluated separately for the mesial and distal canals. Data were analyzed using ANOVA and Tukey tests (P < 0.05). It was found that the BL group had a higher % of unprepared area for both root canals compared to the XP and RC groups (P < 0.05). However, there was no difference in the % of dentin removed between groups (P > 0.05). Based on the studies, it is concluded that there is no justification for the use of EMI since in general, UltraAC did not promote advantages over TradAC and the use of instruments with reduced taper resulted in a larger unprepared area, which could possibly influence the cleaning of the root canal system (AU)

Effect of passive ultrasonic irrigation on hard tissue debris removal: a systematic review and meta-analysis

Abstract: Accumulated hard tissue debris (AHTD) in root canal irregularities may negatively impact adequate root canal disinfection. In light of this, the efficacy of passive ultrasonic irrigation (PUI) to reduce AHTD has been largely studied in in vitro studies, which have adopted different analytic methods of varying accuracy to determine the extent of AHTD more correctly. Therefore, the aim of this study was to compare how well PUI and non-activated irrigation (NAI) systems perform in reducing AHTD during final irrigation protocols, based exclusively on studies whose analyses used microCT scanning. A systematic search of the studies published up to April 2020 was performed using MeSH terms and free terms, in the following databases: PubMed, Scopus, Web of Science, BVS (Lilacs and BBO) and Embase. The inclusion criteria consisted of laboratory studies that evaluated the amount of AHTD, and compared PUI with NAI protocols using microCT analysis. The risk of bias in the selected studies was assessed critically by two reviewers. A meta-analysis was performed using the RevMan software program (P<0.05), and included studies providing the standardized mean difference (SMD), using a fixed effect model, and adopting a confidence interval of 95%. In all, 3495 studies were identified, three of which met the inclusion criteria. All three were considered as having a low risk of bias. The meta-analysis comparing the ability of PUI and NAI protocols to remove hard tissue debris showed a higher percentage of AHTD reduction (P<0.01) for PUI, with a confidence interval of 1.41 [0.79, 2.02]. The heterogeneity among the studies was 82% (I2). Considering the limitations of the present study, this systematic review and meta-analysis showed that PUI was more effective than NAI in removing hard tissue debris, based exclusively on studies that used microCT scanning to provide a more precise analysis of the two techniques used. The findings presented in the present study reinforce the concept that PUI can increase residue removal and improve the cleanliness of the root canal in endodontic treatments.

Avaliação das características superficiais dos instrumentos Reciproc, Reciproc Blue e Xp-Endo Shaper / Evaluation of the surface characteristics of the Reciproc, Reciproc Blue and Xp-Endo Shaper instruments

Introdução: o controle da qualidade no processo de fabricação dos instrumentos endodônticos é importante uma vez que defeitos e falhas superficiais podem comprometer o preparo dos canais. Objetivo: avaliar a presença de defeitos e falhas do processo de fabricação na superfície de instrumentos Reciproc (R25), Reciproc Blue (RB25) e XP-endo shaper (XP), por meio de microscopia eletrônica de varredura (MEV). Materiais e Métodos: Ao total, foram avaliados 60 instrumentos de níquel titânio, sendo 20 por grupo: R25, RB25 e XP, em três regiões: 0mm (ponta do instrumento), 4mm e 7mm da ponta, no MEV, com aumento de 100x. As imagens foram avaliadas quanto ao número de falhas de fabricação (bordo irregular, ranhura, microcavidade e rebarba) e por um sistema de escores de 1 a 4, sendo 1, nenhuma área com defeito e 4, mais de cinco áreas com defeitos na superfície. Os dados foram submetidos à análise estatística utilizando o teste de Dunn (p<0,05). Resultados: Sobre a análise por regiões, foram identificadas diferenças significativas em grande parte dos instrumentos. Comparando os diferentes instrumentos, não foi observada diferença significativa para microcavidade (p=0,76), bordo irregular (p=0,98) e rebarba (p=0,40). O instrumento R25 mostrou maior número de ranhuras em comparação aos demais (p=0,0000*). RB25 mostrou maiores valores de escores que os instrumentos R25 (p= 0,0002) eXP (p=0,01). Conclusão: Todos os instrumentos avaliados apresentaram defeitos/falhas superficiais do processo de fabricação.

Introduction: The quality control of endodontic instruments is extremely importantsince defects and failures on their surface, during their manufacturing process, can compromise the preparation of root canal. Objective: this study evaluated the presence of defects and failures in the manufacturing process on the surface of Reciproc (R25), Reciproc Blue (RB25) and XP endo-shaper (XP) instruments by means of scanning electron microscopy (SEM). Materials and Methods: In total, sixty nickel titanium instruments (n=20): R25, RB25 and XP were evaluated in the scanning electron microscope in three regions: 0mm (tip of the instrument), 4mmand 7mm of the tip, with a magnification of 100x. The images were evaluated in relation to the number of manufacturing faults (irregular border, groove, microcavity and burr) and by a system of scores, from 1 to 4, where 1 is no defective area and 4, more than five areas with defects on the surface. The data were submitted to statistical analysis using Kruskal-Wallis and Mann-Whitney tests (p<0.05). Results: Regarding the analysis by regions, significant differences were identified in most of the instruments. Comparing the different instruments, no significant difference was observed for microcavity (p=0.76), irregular border (p=0.98) and burr (p=0.40). The R25 instrument showed a greater number of grooves compared to the others (p=0.0000*). RB25 showed higher scores than the R25(p=0.0002) and XP (p=0.01) instruments. Conclusion: All evaluated instruments showed defects/failures in the manufacturing process.Introduction: The quality control of endodontic instruments is extremely importantsince defects and failures on their surface, during their manufacturing process, can compromise the preparation of root canal. Objective: this study evaluated the presence of defects and failures in the manufacturing process on the surface of Reciproc (R25), Reciproc Blue (RB25) and XP endo-shaper (XP) instruments by means of scanning electron microscopy (SEM). Materials and Methods: In total, sixty nickel titanium instruments (n=20): R25, RB25 and XP were evaluated in the scanning electron microscope in three regions: 0mm (tip of the instrument), 4mmand 7mm of the tip, with a magnification of 100x. The images were evaluated in relation to the number of manufacturing faults (irregular border, groove, microcavity and burr) and by a system of scores, from 1 to 4, where 1 is no defective area and 4, more than five areas with defects on the surface. The data were submitted to statistical analysis using Kruskal-Wallis and Mann-Whitney tests (p<0.05). Results: Regarding the analysis by regions, significant differences were identified in most of the instruments. Comparing the different instruments, no significant difference was observed for microcavity (p=0.76), irregular border (p=0.98) and burr (p=0.40). The R25 instrument showed a greater number of grooves compared to the others (p=0.0000*). RB25 showed higher scores than the R25(p=0.0002) and XP (p=0.01) instruments. Conclusion: All evaluated instruments showed defects/failures in the manufacturing process.

Análise da morfologia dos canais radiculares de pré-molares inferiores por meio da tomografia computadorizada de feixe cônico / Analysis of the root canal morphology of mandibular premolars using cone-beam computed tomography

O sucesso do tratamento endodôntico de- pende da limpeza e da modelagem dos canais radiculares. Para tanto, deve-se ter um conhecimento profundo sobre a anatomia do sistema de canais radiculares. No entanto, essa anatomia é complexa, com variações mor- fológicas em diferentes populações. Objetivo: O objetivo desse trabalho foi avaliar, em imagens de tomografia computadorizada de feixe cônico (TCFC), a anatomia dos canais radiculares de pré-molares (PM) inferiores de uma população brasileira. Métodos: Foram analisados 426 pré-molares inferiores nos cortes axiais, coronais e sagitais de TCFC. O número de raízes, canais radiculares e a classificação de Vertucci foram tabulados no programa Microsoft Excel. Associações entre o sexo, número de raízes e canais, e classificação de Vertucci foram avaliadas por meio do teste qui-quadrado (p<0,05). Resultados: dos 426 dentes avaliados, 224 (52,6%) foram 1oPM e 202 (47,4%), 2o PM. Os 1oPM apresentaram, em sua maioria, uma raiz (93,3%) e todos os 2oPM, apenas uma raiz. Nos dentes estudados, verificou-se classificação tipos I, II e V de Vertucci, sendo o tipo I o mais encontrado. O tipo V só esteve presente nos 1oPM com duas raízes (p<0,001). Não houve associação significativa entre o número de raízes e o sexo (p=0,182). Conclusão: A maioria dos pré-molares inferiores apresentou uma raiz com classificação tipo I de Vertucci, demonstrando uma baixa variação anatômica nos PM inferiores da população estudada. Não houve predileção por sexo, quanto ao número de raízes e à classificação do tipo de canal radicular.

Introduction: The success of an endodontic treatment depends primarily on cleaning and shaping of the root canal system. Therefore, the anatomy of the root canal system should be known in detail. However, this anatomy is complex and varies morphologically in different populations. This study evaluated the root canal anatomy of mandibular premolars in a Brazilian population using cone beam CT (CBCT). Methods: CBCT axial, coronal and sagittal slices of 426 mandibular premolars were analyzed. Number of roots and canals, as well as Vertucci type, were recorded using a spreadsheet. Associations between sex, number of roots, and Vertucci type were analyzed using a chi-square test (p<0.05). Results: Of the 426 teeth evaluated, 224 (52.6%) were first premolars and 202 (47.4%), second premolars. Most first premolars (93.3%) and all second premolars had one root. Vertucci types I, II and V were found, and type I was the most frequent. Type V was only found in two-rooted first premolars (p<0.001). There were no significant associations between number of root and sex (p=0.182). Conclusion: Most mandibular premolars had one root and were Vertucci type I, which indicates that there is little anatomic variation of these teeth in the Brazilian population under study. There was no sex predilection for number of roots or Vertucci type (AU).

Extrusão apical de debris após o uso de um instrumento reciprocante e uso suplementar de instrumento com liga MaxWire / Apically Extruded Debris Using Reciprocating Single File and Additional Use of MaxWire Allow File

Objetivo: O objetivo deste estudo foi avaliar a quantidade de debris extruídos apicalmente após o preparo do canal com o WaveOne Gold e o uso suplementar do instrumento XP-Endo Finisher. Material e Métodos: Quarenta pré-molares humanos com canal único foram selecionados e divididos em dois grupos (n = 20): preparo com instrumento WaveOne Gold e preparo com instrumento WaveOne Gold + XP-Endo Finisher. Os canais radiculares foram instrumentados seguindo as instruções do fabricante e a água destilada foi usada como irrigante. Debris extruídos apicalmente durante a instrumentação foram coletados em tubos Eppendorf pesados previamente em balança analítico. O peso dos detritos extruídos foi estabelecido subtraindo-se o peso pré-instrumentação e pós-instrumentação dos tubos Eppendorf para cada grupo. Resultados: Os dados foram analisados pelos testes de Shapiro-Wilk e Mann-Whitney, com nível de significância de 5%. Não houve diferença significativa entre os grupos (p = 0,66) em relação à quantidade debris extruídos apicalmente. Conclusão: A presença de debris extruídos apicalmente ocorreu nos dois grupos; no entanto, o uso adicional do instrumento XP-Endo Finisher não contribuiu para o aumento significativo da extrusão apical de detritos quando comparado ao uso isolado do instrumento WaveOne Gold.

Objective: the aim of this study was to evaluate the amount of apically extruded debris after the preparation with WaveOne Gold and additional use of XP-Endo Finisher file. Material and Methods: Forty human one-rooted premolars were selected and divided into two groups (n=20): WaveOne Gold and WaveOne Gold and XP-Endo finisher. Subsequently, the root canals were instrumented following the manufacturer's instructions and distilled water was used as irrigant. Apically extruded debris during instrumentation was collected into pre-weighed Eppendorf tubes. The weight of the dry extruded debris was established by subtracting the pre-instrumentation and postinstrumentation weight of the Eppendorf tubes for each group. Results: The data were analyzed using Shapiro-Wilk and Mann-Whitney tests, with significant level of 5%. There was no significant difference between groups (p=0.66) in relation to apically extruded debris. Conclusion: apically extruded debris occurred in both groups; however, the additional use of the XP-Endo Finisher instrument did not contribute to the significant increase of apical extrusion of debris when compared to the isolated use of WaveOne Gold

Avaliação do tratamento endodôntico em sessão única e retratamento não cirúrgico com alargamento foraminal de dentes com periodontite apical / Evaluation of single visit endodontic treatment and non-surgical retreatment with foraminal enlargment of teeth with apical periodontitis ?

Objective: to evaluate the root canal treatment (RCT) and non-surgical root canal retreatment (NSRCR), associated with foraminal enlargement, performed on a singlevisit. Material and Methods: 125 teeth with apical periodontitis and follow-up period ranging from 6 to 12 months were included. The success was considered by the absence of signs and symptoms and complete or incomplete periapical repair. Logistic regression analyses were used to identify factors associated with the repair (p<0.05). Results: RCT showed 71.58% of complete healing and 23.16% of acceptable healing. NSRCR showed 80% of complete healing and 20% of acceptable healing. Age, gender, type of treatment and preoperative pain were not statistically significant for the healing process (p>0.05). Premolars showed the greatest chance of periapical repair. Pulp Canal Sealer showed a greater chance of periapical repair when compared to Sealapex (p<0.05). Conclusion: RCT and NSRCR using a foraminal enlargement protocol provided a favorable prognosis of periapical healing

Objetivo: avaliar o tratamento endodôntico (TE) e o retratamento não cirúrgico do canal radicular (RNCCR), associado a ampliação foraminal, realizado em sessão única. Material e Métodos: foram incluídos 125 dentes com periodontite apical e proservação de 6 a 12 meses. O sucesso foi considerado pela ausência de sinais e sintomas e reparo periapical completo ou incompleto. Análises de regressão logística foram utilizadas para identificar fatores associados ao reparo (p<0,05). Resultados: o TE mostrou 71,58% de cicatrização completa e 23,16% de cicatrização aceitável. O RNCCR mostrou 80% e 20% cicatrização completa e aceitável, respectivamente. Idade, sexo, tipo de tratamento e dor pré-operatória não foram estatisticamente significantes para o processo de cicatrização (p>0,05). Os pré-molares apresentaram a maior chance de reparo periapical. O cimento Pulp Canal Sealer mostrou maior chance de reparo periapical quando comparado ao Sealapex (p<0,05). Conclusão: o TE e RNCCR utilizando um protocolo de alargamento foraminal, proporcionaram um prognóstico favorável da cicatrização periapical

Capacidade de Adesão de Cimentos Biocerâmicos e Resinosos com a Dentina Radicular: Uma Revisão Integrativa / Adhesion capacity of bioceramic and resin-based root canal sealer to root dentin: an integrative review

Objetivo: comparar a capacidade de adesão do cimento biocerâmico EndoSequence BC e do cimento resinoso AH Plus através de uma revisão integrativa. Material e Métodos: os bancos de dados online Medline/PubMed, Scopus, Web of Science e BVS foram utilizados para a revisão da literatura. Os critérios de elegibilidade incluíram artigos disponíveis na íntegra nas bases de dados pesquisadas, em inglês, e o conteúdo referente à adesão do cimento Endosequence BC sealer em comparação ao AH Plus. Resultados: foram encontrados 45 artigos. Após a remoção duplicada, 22 artigos foram selecionados. Após a leitura dos resumos, textos completos e aplicação dos critérios de inclusão, foram incluídos no total oito artigos. Em relação à capacidade de adesão dos cimentos testados, o AH Plus apresentou melhor adesão do que o cimento BC sealer em três artigos e menor adesão em dois artigos. Força de adesão semelhante foi observada entre os grupos em três estudos. Conclusões: com base nos estudos incluídos, o AH Plus apresenta maior resistência de união quando comparado ao BC Sealer

Aim: To compare the adhesion capacity of the bioceramic EndoSequence BC sealer and the AH Plus sealer through an integrative review. Methodology: The Medline/PubMed, Scopus, Web of Science and VHL online databases were used for the literature review. Eligibility criteria comprised articles available in full on the researched databases, in English, and content addressing Endosequence BC sealer adhesion compared to AH Plus sealer. Results: A total of 45 articles were found. After duplicate removal, 22 articles were selected. After reading the abstracts, full texts and applying the inclusion criteria, eight articles in total were included in the present study. Concerning the adhesion capacity of the tested cements, the AH Plus was reported as presenting better adhesion than the BC sealer in three articles, and less adhesion in two articles. Similar adherence strength was observed between groups in three studies. Conclusions: Based on the included studies, the AH Plus displays greater bond strength when compared to the BC Sealer.

Efeito do consumo de álcool no desenvolvimento de lesão periapical induzida em ratos: uma análise microtomográfica / The Effect of Alcohol Consumption on the Development of Periapical Lesion Induced in Rats: a Micro-CT Analysis

Objetivo: O objetivo deste estudo foi avaliar a influência do consumo crônico de álcool no aumento da destruição óssea periapical em ratos. Material e métodos: Foram selecionados 12 ratos machos da linhagem Wistar, aleatoriamente divididos nos grupos controle e álcool (n=6). Os ratos do grupo álcool foram submetidos à auto-administração de solução alcoólica contendo 25% de álcool puro. O grupo controle recebeu apenas água filtrada durante o estudo. Após as 5 semanas de adaptação do grupo álcool, todos os ratos foram anestesiados e a polpa dos seus primeiros molares inferiores esquerdos foi exposta à cavidade oral para indução da lesão periapical. Após 28 dias de exposição pulpar, os ratos foram sacrificados por sobredose de anestesia, e suas mandíbulas foram removidas e seccionadas para avaliação microtomográfica. As hemimandíbulas esquerdas foram fixadas e escaneadas no microtomógrafo SkyScan 1173 (Bruker, Kontich, Belgium). O tamanho da lesão periradicular foi medido a partir das imagens de microtomografia computadorizada (micro-CT), onde foram calculados a área de superfície e o volume da lesão. Também foram avaliadas a taxa percentual de ganho de peso e a ingestão de sólidos/líquidos dos grupos. Os dados foram estatisticamente analisados utilizando o teste t de Student (p<0,05). Resultados: Os animais do grupo controle tiveram uma maior taxa percentual de ganho de peso corporal e de ingestão tanto de sólidos como de líquidos (p<0,05). As lesões periapicais apresentaram maior volume e maior área nos animais do grupo álcool, em comparação ao grupo controle (p<0,05). Conclusão: O consumo crônico de álcool contribuiu para o aumento da destruição óssea periapical em casos de periodontite apical.

Objective: the aim of this study was to evaluate the influence of alcohol consumption on the increase of periapical bone destruction in rats. Material and Methods: the sample included 12 Wistar male rats, randomly assigned into a control group and an alcohol group (n=6). Rats in the alcohol group were submitted to self-administration of a 25% pure alcoholic solution. The control group received only filtered water throughout the study. After 5 weeks of adaptation to the alcohol dose, all animals were anesthetized and the pulps of their mandibular left first molar were exposed to the oral cavity to induce periapical lesion. Twenty-eight days after the pulp exposure, those rats were euthanized due to overdose of anesthesia and their mandibles were removed and sectioned to obtain a micro-computed tomographic (micro-CT) scan. The rats' left hemimandibles were fixed and scanned on the SkyScan 1173 (Bruker, Konitch, Belgium) microtomograph. The size of the periradicular lesions was measured from the images obtained on the micro-CT and the surface area and volume were calculated. It was also evaluated the weight gain rate and the ingestion of solid/liquid of both groups. Data were analyzed by the Student's t-test (p<0.05). Results: the control group showed higher rates of weight gain and ingested more solid and liquid than the alcohol group (p<0.05). Periapical lesions found in the alcohol group had higher volume and surface area than the ones of the control group (p<0.05). Conclusion: the chronic consumption of alcohol contributed to the increase of periapical bone destruction in cases of apical periodontitis

Biodentine: um substituto ao MTA? / Biodentine: an alternative to MTA?

Objetivo: o objetivo desse estudo é realizar uma revisão de literatura em relação às propriedades físico- -químicas e biológicas do Biodentine, seu emprego na Endodontia e discutir, com base nas evidências científicas encontradas na literatura, se esse material poderá ser um substituto ao MTA. Métodos: foi realizada uma busca na literatura na base de dados PubMed, usando os termos em inglês: Biodentine, calcium silicate, MTA, properties, setting time, radiopacity, solubility, physicochemical properties, porosity, hydration, biocompatibility, bioactivity, microhardness, compressive strength, bond strength, irrigants, furcal perforation, retrograde filling material, revitalization, revascularization, endodontics, apexification. Cinquenta artigos foram incluídos. Resultados: os artigos revisados sugerem que o Biodentine tem características favoráveis e que tem alcançado resultados promissores em relação ao MTA. Conclusão: o Biodentine pode ser considerado um eventual substituto ao MTA (AU).

Introduction: This study aim to review the literature about the physicochemical and biological characteristics of Biodentine, a cement used in endodontics, and discussed whether this material might be an alternative to MTA according to the scientific evidence found in the literature. Methods: A literature search was performed on PubMed using the following terms: Biodentine, calcium silicate, MTA, properties, setting time, radiopacity, solubility, physicochemical properties, porosity, hydration, biocompatibility, bioactivity, microhardness, compressive strength, bond strength, irrigants, furcal perforation, retrograde filling, revitalization, revascularization, endodontics, apexification. Fifty studies met inclusion criteria. Results: Biodentine seems to have favorable characteristics, and the results of its use are promising when compared with those of MTA. Conclusion: Biodentine may be a possible alternative to MTA (AU).

Efeito de diferentes protocolos de irrigação final na remoção da smear layer / Effect of different protocols of final irrigation on smear layer removal

Objetivo: esse estudo avaliou o efeito de protocolos de irrigação final, associados ao uso de EDTA e QMix, na remoção de smear layer. Métodos: foram utilizados 40 dentes humanos com canal único. Os canais foram instrumentados com sistema ProTaper Universal SX-F3. As substâncias químicas utilizadas durante o preparo foram hipoclorito de sódio a 5,25% (NaOCl) ou clorexidina a 2% (CHX) gel. Terminado o preparo, os dentes foram divididos em oito grupos, de acordo com os irrigantes: G1) NaOCl 5,25% + EDTA 17% + NaOCl 5,25%; G2) NaOCl 5,25% + EDTA 17% + água destilada (AD); G3) NaOCl 5,25% + QMix + NaOCl 5,25%; G4) NaOCl 5,25% + QMix + AD; G5) CHX 2% gel + EDTA 17% + CHX 2% solução; G6) CHX 2% gel + EDTA 17% + AD; G7) CHX 2% gel + QMix + CHX 2% solução e G8) CHX 2% gel + QMix + AD. As amostras foram avaliadas por microscopia eletrônica de varredura ambiental, antes e após os protocolos de irrigação final. As imagens foram classificadas por escores, em relação à presença de smear layer, e os dados foram analisados pelos testes de Kruskal-Wallis e de Mann-Whitney. Resultados: o G1 mostrou os melhores resultados em relação à remoção de smear layer (p < 0,05). A CHX gel 2% mostrou menor formação de smear layer, quando comparada ao NaOCl, após o preparo biomecânico; e o NaOCl apresentou melhor limpeza como irrigante final (p < 0,05). Conclusões: o NaOCl como irrigante final, combinado ao EDTA, mostrou melhor capacidade de remoção da smear layer (AU).

Introduction: This study evaluated the effect of different final irrigation protocols using EDTA and QMix on smear layer removal. Methods: The root canals of 40 single-rooted human teeth were prepared with ProTaper Universal SX - F3. The substances used were 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine gel (chlorhexidine), 2% chlorhexidine solution and distilled water. The teeth were divided into 8 groups, according to the irrigant used: G1: 5.25% NaOCl + 17% EDTA + 5.25% NaOCl; G2: 5.25% NaOCl + 17% EDTA + distilled water; G3: 5.25% NaOCl + QMix + 5.25% NaOCl; G4: 5.25% NaOCl + QMix + DW; G5: 2% chlorhexidine gel + 17% EDTA + 2% chlorhexidine solution; G6: 2% chlorhexidine gel + 17% EDTA + distilled water; G7: 2% chlorhexidine gel + QMix + 2% chlorhexidine solution; and G8: 2% chlorhexidine gel + QMix + distilled water. Samples were evaluated under environmental scanning electron microscopy (ESEM) before and after irrigation. ESEM images were classified according to smear layer scores, and the Kruskal-Wallis and Mann-Whitney tests were used for statistical analyses. Results: Group 1 had the best results for smear layer removal (p<0.05). Smear layer formation was lower when 2% chlorhexidine gel was used after cleaning and shaping than when the irrigant was 5.25% NaOCl, and 5.25% NaOCl had the best cleaning ability as a final irrigant. Conclusion: 5.25% NaOCl combined with EDTA was the best final irrigant for smear layer removal (AU).

Tendências atuais em irrigação, entre os endodontistas brasileiros / Current trends in irrigation among Brazilian endodontists

Introdução: diferentes irrigantes têm sido estudados, propostos e utilizados durante a terapia endodôntica. Objetivo: o objetivo deste estudo foi determinar as tendências atuais em irrigação, entre os endodontistas brasileiros. Métodos: um total de 398 endodontistas brasileiros respondeu a um questionário de pesquisa na internet, com 15 questões de múltipla escolha, seleções múltiplas e rankings numéricos, sobre sua seleção de irrigante, concentração, remoção da smear layer e uso de coadjuvantes para irrigação. Resultados: o hipoclorito de sódio foi o irrigante mais utilizado em uma concentração inferior a 5,0%. Clorexidina (CHX) foi o segundo irrigante primário mais utilizado, sendo a CHX 2% em gel a forma de apresentação mais prevalente. Em relação à remoção da smear layer, 88,4% dos entrevistados declararam realizar a remoção, onde o EDTA foi o irrigante mais utilizado (93,7%). Mais de 70% dos endodontistas utilizam um sistema coadjuvante durante a irrigação, dos quais 39,9% utilizam ativação ultrassônica; 24,4%, lima plástica e 1%, ativação sônica. O uso de EndoVac não foi relatado. Conclusões: a maioria dos entrevistados utiliza hipoclorito de sódio e remove rotineiramente a smear layer durante o tratamento endodôntico utilizando EDTA. Os endodontistas brasileiros utilizam técnicas coadjuvantes à irrigação. (AU)

Effect of a sonic device on bonding of fiberglass posts to root canals

Aim: This study evaluated the effect of a sonic device on the bonding of fiberglass posts cemented with a self-etching adhesive combined with conventional cement or a self-adhesive cement to root dentin. Methods: Forty single-rooted bovine incisors were endodontically prepared using a step-back technique. Gutta-percha and AH Plus sealer were used for root canal filling, combined with a thermoplasticization technique. After 1 week, the post space was prepared and the roots were divided into four groups according to the following factors: adhesive system/resin cement (Ambar/ AllCem Core [FGM] and RelyX U200 [3M]) and application mode (manual or sonic). The posts were cemented and the roots were cut into discs and submitted to push-out bond strength (POBS) test. The failure mode was evaluated using a stereoscope at 25x magnification. The data were analyzed statistically using ANOVA and Tukey's post-hoc test (α = 0.05). Results: The sonically activated RelyX U200 group was superior to the other groups. RelyX U200 manually applicated showed similar results to those of sonically activated Âmbar/AllCem. These three groups outperformed the Âmbar/AllCem manually applicated group. Adhesive failure between dentin and resin cement was the most predominant pattern. Conclusion: Sonic application of self-etching adhesive and self-adhesive cement improved the POBS of fiber posts to the root canal

Efeito de agentes dessensibilizantes na obliteração dos túbulos dentinários - estudo in vitro / Effect of desensitizing agents for dentinal tubules obliteration - in vitro study

Objetivo: avaliar o número de aplicações necessárias para a completa obliteração dos túbulos dentinários utilizando diferentes agentes dessensibilizantes. Material e Métodos: a porção do esmalte coronário da face vestibular de 40 incisivos bovinos foi removida com auxílio de lixas para expor a dentina superficial da junção amelo-cementária. Em seguida, as raízes e a porção coronária referente ao terço médio-incisal dos dentes foram removidas. A seguir foi realizada a completa remoção de smear layer, evidenciando os túbulos dentinários. As amostras foram divididas em quatro grupos experimentais conforme o agente dessensibilizante utilizado: verniz fluoretado, adesivo dentinário, dessensibilizante dentinário e creme dental. Os produtos foram aplicados de acordo com as recomendações do fabricante. As amostras foram avaliadas previamente e após o uso dos agentes por microscopia eletrônica de varredura de baixo vácuo. A aplicação do agente e a análise foram realizadas até a completa obliteração dos túbulos dentinários. Os dados foram avaliados estatisticamente em relação ao número de aplicações necessárias utilizando os testes de Kruskal-Wallis e Mann-Whitney (p < 0,05). Resultados: o verniz fluoretado foi o mais eficaz dos agentes avaliados, sendo necessária uma aplicação para a completa obliteração dos túbulos. Para o adesivo dentinário foram necessárias duas aplicações e para o dessensibilizante e o creme dental foram necessárias cinco aplicações. Conclusão: os agentes dessensibilizantes testados necessitam de um número variado de aplicações, sendo o mais eficaz o verniz fluoretado, onde apenas uma aplicação possibilitou a completa obliteração dos túbulos.

Objective: The aim of this study was to evaluate the number of applications necessary for the complete obliteration of dentinal tubules using different desensitizing agents. Materials and Methods: A portion of coronary enamel of the buccal surface of 40 bovine incisors was removed with the aid of sandpaper in order to expose the superficial dentin at the dentin-enamel junction. The roots and the coronary portions of the mesial-incisal third of the teeth were also removed. Complete smear-layer removal was performed, exposing the dentinal tubules. Samples were divided into four experimental groups according to the desensitizing agents used: fluoride varnish; dentin adhesive; dentin desensitizing; and toothpaste. The products were applied in accordance with the manufacturer's recommendations. Samples were evaluated before and after the application of different agents by scanning electronic microscopy of low vacuum. The application of the products and analyses were carried out until complete obliteration of dentinal tubules. Data were evaluated statistically in relation to the required number of applications, using Kruskal-Wallis and Mann-Whitney tests (p < 0.05). Results: The results showed that fluoride varnish was the most efficient of the tested agents, requiring a single application for the complete obliteration of the dentinal tubule. For the dentin adhesive, two applications were necessary and for the dentin desensitizing and toothpaste, five applications were required. Conclusion: The desensitizing agents tested required a distinct number of applications, and the fluoride varnish was the most effective agent, with a single application resulting in the complete obliteration of the dentin tubule.