Resumo Lesões Cervicais Não Cariosas (LCNC) são defeitos do tecido dentário, não relacionados à cárie, frequentemente observados na prática odontológica. O objetivo do estudo foi avaliar os efeitos da profundidade e espessura da dentina de LCNC na resposta à dor dentária por meio de testes de diagnóstico clínico. 86 dentes de 14 pacientes com LCNC foram avaliados por: profundidade da LCNC, testes clínicos (estímulo evaporativo, para detectar níveis de dor de hipersensibilidade dentinária, teste térmico frio para classificar a saúde pulpar, estímulos percussivos para avaliação do tecido perirradicular e tomografia computadorizada de feixe cônico (TCFC), para avaliação da espessura de dentina remanescente (EDR). Em termos de profundidade, a amostra foi dividida em dois grupos: G1- dentes com LCNCs ≤1,0mm e G2- dentes com LCNCs entre 1,1-2,0 mm. Os dados de dor dentária foram comparados pelo teste de Mann-Whitney e a EDR pelo teste t-Student e correlações pelo teste de Pearson (p <0,05). A profundidade da LCNC não influencia a resposta da dor dentária ao estímulo evaporativo (p = 0,129, teste térmico frio (p = 0,125), teste diagnóstico clínico de percussão vertical (p = 0,317) e horizontal (p = 0,119), porém o G1 apresentou maior EDR (p <0,001) e o teste de correlação mostrou que LCNC mais profunda apresenta menor EDR (p = 0,011 / r = -0,273). Conclusão: Dentes com LCNC de até 2mm de profundidade apresenta níveis semelhantes de dor para hipersensibilidade dentinária, pulpar e saúde perirradicular, independente da profundidade da LCNC. Entretanto, lesões com profundidade ≤1,0mmin apresentaram mais EDR nos achados tomográficos.

Abstract Non-carious Cervical Lesions (NCCL) are dental tissue defects, non-related to caries, frequently observed in the dental practice. The aim of this study was to evaluate the effects of NCCL on dentin depth and thickness and the response to dental pain by means of clinical diagnostic tests. 86 teeth from 14 patients with NCCL were assessed by: depth of NCCL, clinical tests (evaporative stimulus, to detect pain levels of dentin hypersensitivity, cold thermal test to classify pulp health, percussive stimuli to evaluate the periradicular tissues and cone beam computed tomography (tomography to evaluate remaining dentin thickness (RDT). In terms of depth, the sample was divided into two groups: G1- teeth with NCCLs ≤1.0mm and G2- teeth with NCCLs between 1.1-2.0 mm. Dental pain data were compared by Mann-Whitney test and RDT by Student’s t-test and correlations by the Pearson test (p<0.05). The depth of NCCL does not influence dental pain response to evaporative stimulus (p=0.129), cold thermal test (p = 0.125), vertical (p = 0.317) and horizontal (p = 0.119) percussion clinical diagnostic tests. However, G1 showed more RDT (p<0.001), and the correlation test showed that deeper NCCL presents smaller remaining dentin thickness (p=0.011/r=-0.273). In conclusion, tooth with NCCL up to 2mm-depth presents similar levels of pain for dentin hypersensitivity, pulp and periradicular tissue independent to NCCL depth, however, lesions with ≤1.0mm-depth showed greater RDT in tomographic findings.

The aim of this study was to evaluate the influence of the flexion angle of files on the decentralization of root canals during instrumentation. Fifteen lower incisors were instrumented with Protaper Universal files and radiographed in two directions (mesiodistal and buccolingual) before and after instrumentation with a #15 K-file in position for evaluating the flexion angle of files. The specimens were also scanned before and after instrumentation using micro-computed tomography to obtain the canal area and the distance from the center position of the file to the canal walls. Sections located 1.0 mm (end of the canal), 3.0 mm (apical third), 9.0 mm (middle third), and 15.0 mm (cervical third) from the apex were verified. After instrumentation, the flexion angles of files decreased by an average of 0.76º in the buccolingual direction and 1.92º in the mesiodistal direction (p < 0.001); the canal area increased by an average of 0.58, 0.37, 0.23 and 0.13 mm2 from the cervical to the end of the root canal (p < 0.001). Non-instrumented areas were observed on the buccal and lingual walls, and effective action of files was determined on the mesial and distal walls. The sections from the end of the canal showed canal deviation toward the lingual wall, whereas the other sections showed deviation toward the buccal wall. The flexion angles of files influence the final shape of the root canal, resulting in file decentralization along the pathway of the canal.

Este estudo avaliou a anatomia do canal radicular de incisivos inferiores, antes e após a instrumentação endodôntica, identificando regiões inacessíveis à ação das limas (Área Crítica de instrumentação - AC), em uma perspectiva tridimensional. Trinta incisivos centrais inferiores humanos foram selecionados, divididos em dois grupos (n=15), e instrumentados usando limas rotatórias ProTaper Universal. No grupo RX, imagens longitudinais foram obtidas em duas incidências, vestíbulo-lingual (VL) e mésio-distal (MD), por meio de radiografias digitais. No grupo CT, imagens transversais foram obtidas por meio de microtomografia computadorizada (μTC), em secções localizadas a 3 mm, 9 mm, e 15 mm do ápice. A área do canal das amostras foi avaliada antes e após a instrumentação usando as imagens digitais de cada grupo. Os dados foram analisados por meio do teste t, ANOVA a um critério com parcela subdividida e ao teste de Tukey (α=0,05). A área de canal encontrada nas radiografias MD foi maior do que nas radiografias VL, o que também foi confirmado nas imagens transversais (p<0,01). A Área Crítica de instrumentação só foi detectada nas radiografias MD e nas seções de μTC. Na configuração de canal, a redução contínua na conicidade do canal foi observada nas radiografias VL, enquanto na incidência MD, houve uma constrição no terço cervical e um subsequente aumento no terço médio (p<0,01). A forma cônica do canal radicular foi observada somente na visão VL. O alargamento do canal verificado nas radiografias VL não foi indicativo de instrumentação homogênea, uma vez que áreas não instrumentadas (AC) foram observadas nas paredes vestibular e lingual em visões distintas.

The aim of this study was to evaluate the root canal anatomy of mandibular incisors before and after endodontic instrumentation, identifying regions inaccessible to the action of files (Critical instrumentation Area - CA) in a three-dimensional perspective. Thirty human mandibular central incisors were selected, assigned to two groups (n=15) and instrumented using ProTaper Universal rotary files. In the RX group, longitudinal digital radiographic images were obtained in the buccolingual (BL) and mesiodistal (MD) views. In the CT group, cross-sectional micro-computed tomography (µCT) images were obtained at 3, 9 and 15 mm from the apex. The canal area of the specimens was evaluated before and after instrumentation using digital images from each group. Data were analyzed using t-test, one-way ANOVA with subdivided parcels and Tukey's test (α=0.05). The canal area found in the MD radiographs was larger than in the BL radiographs, which was also confirmed in the transversal images (p<0.01). The CA was only detected in the MD radiographs and µCT scans. On the root canal configuration, a continuous reduction in the canal conicity was observed in BL radiographs, while in MD view there was a constriction at the cervical third and subsequent increase at the middle third (p<0.01). The conical shape of the root canal was observed only in the BL view. The canal enlargement in BL radiographs was not indicative of homogeneous instrumentation, since unprepared areas (CA) were also verified on the buccal and lingual walls in different images

The dental pulp may be exposed to several irritants that are potentially noxious to the health and functions of this tissue. Each type of irritant or injury has different effects on the pulp, which are generally characterized by acute inflammation, chronic inflammation or necrosis. Common examples of irritants are dental caries, cavity preparation procedures, traumatic injuries, and chemical substances like bleaching agents and adhesive systems. The present study aimed to review the current knowledge about the effect of bleaching agents and adhesive systems in the human dental pulp. The review covered literature from 2004 to 2009, and only relevant manuscripts were included. Hand search of the references completed the review. Based on literature review, it may be concluded that all dental procedures associated with bleaching agents or adhesive systems involve risks to cause pulp damage. However, these risks can be minimized if the causal factors were known and avoided.