Abstract This study evaluated the interference of enamel and coronal dentin thickness and ambient light in pulse oximetry interpretation, using SaO2the human finger as a reference. Forty-two intact human permanent mandibular molars were sectioned mesiodistally in the central portion. Buccal and lingual dentin surfaces were drilled, and 4 mm, 3 mm and 2 mm enamel/dentin thicknesses were interposed between finger and device, after which SaO2 levels were measured by finger pulse oximetry. A reference device was designed to align pulse oximeter light-emitting diode, buccal surface of tooth, little finger, lingual surface of tooth and photodiode. Variables were described as means and standard deviation, and the confidence interval was reported. Repeated measures analysis of variance (ANOVA) was used to compare the groups, followed by Bonferroni correction. Student t test for paired samples was used to determine presence of ambient light (α = 0.05). Mean SaO2 level was lower at 4.0 ± 0.2 mm thickness, regardless of presence or absence of ambient light (92.7% and 89.3%). The other thicknesses yielded values of 95.5% and 94.5% at 3.0 ± 0.2 mm, and 96.4% and 96.0% at 2.0 ± 0.2 mm (p < 0.001). There were significant differences between SaO2 values at 4.0 ± 0.2 mm, 3.0 ± 0.2 mm and 2.0 ± 0.2 mm thicknesses, in the presence of ambient light. Mean SaO2 level in positive control was 96.3%, and mean pulse rate was 69.5 bpm in presence of ambient light; in the absence of light, these values were 96% and 70.5 bpm. Enamel and dentin thickness interfere with SaO2, regardless of presence or absence of ambient light. The lowest SaO2 levels were found for the thickest tooth samples.

Abstract Objective To assess pulp oxygen saturation levels (SaO2) in maxillary central incisors after dental bleaching. Materials and Methods 80 participants (160 teeth) were randomly allocated to four groups: G1 In-office bleaching with two applications of 35% hydrogen peroxide (HP) (20 minutes), followed by at-home bleaching with 10% carbamide peroxide (CP) (2 hours/day for 16 days); G2 - Same protocol as G1, plus desensitizing toothpaste; G3 - In-office bleaching with 35% HP and one application of placebo gel (20 minutes), followed by at-home bleaching with 10% CP (2 hours/day for 16 days); and G4 - Same protocol as G3, plus desensitizing toothpaste. Pulp SaO2 levels were measured before (T0) and immediately after (T1) in-office bleaching; on the 5th (T2), 8th (T3), 12th (T4), and 16th days of at-home bleaching (T5); and on the 7th (T6) and 30th (T7) days. Mean (SD) pulp SaO2 levels were compared within groups by generalized estimating equations (GEE) and Student’s t-test (P<0.05). Results Mean pulp SaO2 at T0 was 84.29% in G1, 84.38% in G2, 84.79% in G3, and 85.83% in G4. At T1, these values decreased to 81.96%, 82.06%, 82.19%, and 81.15% in G1, G2, G3, and G4 respectively, with significant difference in G4 (P<0.05). During home bleaching, pulp SaO2 levels varied in all groups, with 86.55%, 86.60%, 85.71%, and 87.15% means at T7 for G1, G2, G3, and G4, respectively; G2 presented significant difference (P<0.05). Conclusions Pulp SaO2 level in maxillary central incisors was similar at baseline, reducing immediately after in-office bleaching, regardless of using desensitizing toothpaste and increasing at 30 days after dental bleaching.

Resumo Este estudo verificou o grau de saturação de oxigênio (SaO2) pulpar antes, durante e após o clareamento dental caseiro em incisivos centrais superiores hígidos. O nível de SaO2 foi verificado em 136 incisivos centrais superiores hígidos usando oxímetro de pulso. A técnica de clareamento empregou peróxido de carbamida 10% em moldeira individual por quatro horas diárias durante 14 dias. Os níveis de SaO2 foram analisados antes do clareamento (T0), imediatamente após a primeira sessão (T1), no sétimo dia de tratamento (T2), no décimo quinto dia (um dia após a última sessão) (T3) e 30 dias após o término do clareamento dental (T4). A análise estatística utilizou o modelo de equações de estimações generalizadas (GEE), teste t de Student (p<0,05) e correlação de Pearson. Os níveis médios de SaO2 pulpar foram 85,1% em T0, 84,9% em T1, 84,7% em T2, 84,3% em T3 e 85,0% em T4. Foi observada uma redução gradual dos níveis de SaO2, com diferenças significantes (p<0,001) durante o clareamento dental caseiro. No entanto, 30 dias após o término do clareamento dental, houve retorno aos valores iniciais. O clareamento dental caseiro provocou uma diminuição transitória reversível no grau de SaO2 pulpar.

Abstract The present study assessed oxygen saturation (SaO2) levels before, during, and after at-home bleaching treatment in the pulps of healthy maxillary central incisors. SaO2 levels were measured in 136 healthy maxillary central incisors using a pulse oximeter. The bleaching protocol consisted of 10% carbamide peroxide gel placed in individual trays and used for four hours daily for 14 days. SaO2 levels were assessed before bleaching (T0), immediately after the first session (T1), on the 7th day of treatment (T2), on the 15th day (the day following the last session) (T3), and 30 days after completion of the bleaching protocol (T4). Data were statistically analyzed using generalized estimating equations (GEE), Student’s t test (p<0.05) and Pearson’s correlation. Mean pulp SaO2 levels were 85.1% at T0, 84.9% at T1, 84.7% at T2, 84.3% at T3, and 85.0% at T4. Gradual reductions in SaO2 levels were observed, with significant differences (p<0.001) during the course of home bleaching treatment. However, 30 days after the end of the bleaching protocol, SaO2 levels returned to baseline levels. Home bleaching caused a reversible transient decrease in SaO2 levels in the pulps.

Abstract Revascularization of immature teeth with necrotic pulps traditionally involves the use of triple antibiotic paste, which may sometimes lead to undesirable complications. The objective of this study was to assess tissue repair in immature dog teeth with apical periodontitis subjected to revascularization, comparing two different pastes used for root canal disinfection. Apical periodontitis was induced in 30 dog premolars. Teeth were randomly divided into three experimental groups: root canals filled with triple antibiotic paste (n = 10); root canals filled with 1% propolis paste (n = 10); and no medication (n = 10). An additional group (n = 10, no intervention) was used as control. After 7 months, the jaws were histologically evaluated for the following variables: newly formed mineralized tissue (present/absent); vital tissue in the canal space (absent/periodontal ligament-like/pulp-like); apical extension of root (present/absent); and severity of inflammatory process (absent/mild/moderate/severe). There were no statistically significant differences among the experimental groups in new mineralized tissue formation and apical root development. The formation of vital tissue in the canal space, in turn, was statistically different between the triple paste and propolis groups: vital tissues were present in all revascularized teeth disinfected with propolis paste (100%), compared to 71% of those disinfected with the triple paste. Severity of inflammatory process was different between the triple paste and no medication groups. The new tissues formed onto canal walls and in the root canal space showed characteristics of cementum and periodontal ligament, respectively. Propolis may have some advantages over the triple paste for the revascularization of immature teeth.

The aim of this study was to assess, in vivo, the accuracy of the NovApex® electronic foramen locator in determining working length (WL) in vital and necrotic posterior teeth. The NovApex®was used in 144 canals: 35 teeth with vital pulps (68 canals) and 42 teeth with necrotic pulps (76 canals). WL was measured with the NovApex® locator and confirmed using the radiographic method. Differences between electronic and radiographic measurements ranging between 0.0 and 0.4 millimeters were classified as acceptable; differences equal to or greater than 0.5 millimeter were considered unacceptable. Pearson's chi-square test was used to assess the influence of pulp condition on the accuracy of NovApex®(a = 0.05). Regardless of pulp condition, differences between electronic and radiographic WL measurements were acceptable in 73.61% of the canals. No statistically significant differences in accuracy were observed when comparing vital and necrotic canals (p > 0.05). There were 38 unacceptable measurements. In none of these cases was the file tip located beyond the radiographic apex; in 32, it was located short of the NovApex® measurement. Pulp condition had no significant effect on the accuracy of NovApex®.

Intracanal medication in pulpectomy therapy is used between appointments with the objective of reducing pain and inflammatory processes in pulp and periapical tissues. Propolis has been known as a natural antibiotic and has been subject of medical and dental research due to its therapeutic properties such as antibiotic, analgesic and anti-inflammatory effects. OBJECTIVE: The aim was to carry out an in vivo evaluation of the periapical tissue response to propolis paste when used as an intracanal medication in the teeth of dogs after pulpectomy. MATERIAL AND METHODS: 72 dog's incisors were selected for the experiment. After biomechanical preparation the root canal was filled with a corticosteroid-antibiotic preparation, experimental propolis paste, non-medicament (negative control) or non-pulpectomy at all (positive control). The medications were left inside the root canal for 7, 14 or 28 days. At the end of the experimental period histological sections were prepared and all laboratories processes for Harris hematoxylin and eosin staining was proceeded followed by the analysis using an optical microscope. Sections were classified according to a score representing the inflammatory events observed: the presence of polymorphonuclear neutrophils, polymorphonuclear eosinophils, lymphocytes and plasma cells, macrophages and/or giant cells, fibrous condensation and abscesses. RESULTS: There were statistically significant differences between the tissue reactions caused by the two substances being tested, after different experimental periods, with the periapical tissue that was in contact with propolis paste exhibiting fewer inflammatory reactions in comparison to corticosteroid-antibiotic preparation. CONCLUSIONS: The low tissue responses from propolis paste suggest that this material could be considered as an option for root canal medication after pulpectomy.

Esta pesquisa estudou a flexibilidade de instrumentos do Sistema K3 (conicidade 0.04) e do Sistema ProTaper Universal, por meio de um teste mecânico, quando os instrumentos eram novos e após 5 usos em canais simulados. Cinco jogos de instrumentos de cada sistema foram testados, como segue: grupo I - K3 (15, 20, 25, 30, 35, 40 e 45), e grupo II - ProTaper Universal (S1, S2, F1, F2, F3, F4 e F5). Cada jogo de instrumento foi usado para preparar um canal simulado, e o mesmo jogo de instrumento foi usado 5 vezes (50 canais). O número de cada subgrupo representou o número de usos: 0 (controle), 1, 3 e 5 usos. Antes do uso e depois de cada uso os instrumentos foram submetidos a um teste mecânico de flexibilidade realizado na máquina de ensaios universais Versat 502. A interação entre o instrumento e o número de usos foi analisada pelo ANOVA e pelo teste de Tukey ao nível de significância 5%. Instrumentos de ambos os sistemas apresentaram menor flexibilidade após o terceiro uso quando comparada com a flexibilidade após os usos 0 e 1 (p<0,05), e mantiveram a mesma flexibilidade após o quinto uso. A flexibilidade dos instrumentos do sistema K3 diminuiu conforme o aumento de diâmetro, independente do número de usos. Entre os instrumentos do sistema ProTaper Universal, os shaping apresentaram maior flexibilidade que os finishing. F2 e F3 foram os menos flexíveis e F4 e F5 apresentaram valores de flexibilidade similares ao F1.

This study used a mechanical test to evaluate the flexibility of instruments from the K3 (conicity 0.04) and the ProTaper Universal systems when they were new and after 5 uses in simulated canals. Five sets of instruments of each system were tested: K3 (15, 20, 25, 30, 35, 40 and 45) and ProTaper Universal (S1, S2, F1, F2, F3, F4 and F5). Each set of instruments was used to prepare a simulated canal and the same set of instruments was used 5 times (50 canals). The number of each subgroup represented the number of uses: 0 (control), 1, 3 and 5 uses. Before and after each use, the instruments were submitted to a mechanical flexibility test performed in a Versat 502 universal testing machine. Interactions between the instrument and the number of uses were analyzed by ANOVA and Tukey's test at a 5% level of significance. Instruments from both systems presented lower flexibility after the third use compared to the flexibility obtained after uses 0 and 1 (p<0.05), and maintained the same flexibility after the fifth use. The flexibility of instruments from the K3 system decreased with the increase of diameter, irrespective of the number of uses. Among the instruments from the ProTaper Universal system, the shaping files presented greater flexibility than the finishing files. F2 and F3 were the least flexible instruments, and F4 and F5 presented flexibility values similar to those of F1.

Este estudo utilizou a tomografia computadorizada (TC) para comparar o transporte do canal radicular nos canais mésio-vestibulares de molares superiores preparados por diferentes técnicas. Sessenta molares superiores foram divididos em 3 grupos (n=20) de acordo com a técnica utilizada para o preparo do canal radicular: instrumentação manual com limas K-Flexofile, limas K-Flexofile acopladas a um sistema oscilatório e sistema rotatório ProTaper. Imagens de TC pré e pós-instrumentação foram obtidas 3 mm aquém do forame apical e superpostas para comparar o transporte do canal. Os dados foram analisados estatisticamente pela Análise de Variância (ANOVA) e Teste de Tukey utilizando o software SPSS (α=0,05). Na direção vestibular, a técnica manual produziu significantemente menos transporte do canal radicular do que a técnica oscilatória (p<0,05) e ambas foram similares a técnica rotatória (p>0,05). Nas direções distal e disto-palatina, a técnica oscilatória produziu mais transporte do canal radicular (p<0,05). Na direção mésio-palatina, a técnica oscilatória produziu mais transporte do canal radicular do que a técnica manual (p<0,05), sendo que ambas foram similares à técnica rotatória (p>0,05). Em conclusão, todas as técnicas produziram transporte do canal radicular e a técnica oscilatória produziu os maiores desgastes de dentina na direção interna da curvatura.

This study used computed tomography (CT) to compare apical canal transportation in mesiobuccal canals of maxillary molars prepared with different techniques. Sixty teeth were assigned to 3 groups (n=20), according to the technique used for root canal instrumentation: hand instrumentation with K-Flexofiles, K-Flexofiles activated by an oscillatory system and ProTaper NiTi rotary system. Pre and post-instrumentation CT images were obtained 3 mm short of the apical foramen and were superimposed to compare canal transportation. Data were analyzed statistically by ANOVA and Tukey's test using the SPSS software (α=0.05). In the buccal direction, the manual technique produced significantly less canal transportation than the oscillatory technique (p<0.05) and both were similar to the rotary technique (p>0.05). In the distal and distopalatal directions, the oscillatory technique produced more canal transportation (p<0.05). In the mesiopalatal direction, the oscillatory technique produced more canal transportation than the manual technique (p<0.05), and both were similar to the rotary technique (p>0.05). In conclusion, all techniques produced canal transportation, and the oscillatory technique produced the greatest removal of root dentin toward the innerside of the root curvature.

OBJETIVO: Avaliar o efeito do pré-alargamento sobre a medição eletrônica do comprimento de trabalho em raízes mésio-vestibulares de molares superiores. METODOLOGIA: Trinta raízes foram incluídas em um modelo de alginato. Canais radiculares foram irrigados com hipoclorito de sódio a 2,5%, e uma lima de tamanho 10 K foi inserida no canal até onde o localizador indicou que a constrição apical tinha sido alcançada. A porção cervical de cada canal foi alargada usando as limas do sistema ProTaper, quando então as medições eletrônicas foram realizados novamente. RESULTADOS: O teste t de Student para amostras pareadas não mostrou diferenças estatisticamente significativas nas medições obtidas para canais pré-alargados e não alargados (P<0,05). CONCLUSÃO: Com base na falta de relevância clínica significativa das comparações realizadas no presente estudo, é possível concluir que a medição do comprimento eletrônico de trabalho pode ser realizado antes ou após o preparo cervical.

PURPOSE: To evaluate the effect of preflaring on the electronic measurement of working length in mesiobuccal roots of maxillary molars. METHODS: Thirty roots were embedded in an alginate model. Root canals were irrigated with 2.5% sodium hypochlorite, and a size 10 K file was inserted into the canal until the locator indicated that apical constriction had been reached. Then, the cervical portion of each canal was flared using the ProTaper system shaping files, whereupon electronic measurements were carried out again. RESULTS: The Student's t test for paired samples did not reveal statistically significant differences in the measurements obtained for preflared and unflared canals (P<0.05). CONCLUSION: Based on the lack of clinical significant relevance of the comparisons carried out in the present study, it is possible to conclude that electronic working length measurement can be carried out either before or after cervical preparation.

OBJETIVO: Descrever o tratamento endodôntico de um canino superior medindo 36 mm de comprimento, mostrando a técnica empregada no preparo do canal radicular e obturação. DESCRIÇÃO DO CASO: Paciente do sexo masculino, com 32 anos de idade, sofreu subluxação dos dentes 12 e 13 e fratura coronária envolvendo esmalte e dentina, com exposição pulpar do dente 14, devido a um acidente de moto. No atendimento de urgência, foi realizada a contenção semirrígida dos dentes 12 e 13, seguida da endodontia em sessão única do dente 14. Trinta dias após, foi diagnosticada necrose pulpar dos dentes 12 e 13 e sua endodontia foi, então, iniciada. O comprimento aparente do dente 13 foi estabelecido em 36 mm e como o instrumento mais longo que dipomos no mercado possui 31 mm, o limite cervical da cavidade de acesso foi usado como bordo de referência. CONCLUSÃO: Além de garantir uma correta sanificação, modelagem e obturação do canal, esta técnica também permitiu a preservação da estrutura dental remanescente.

PURPOSE: To report a clinical case of a 36 mm long upper cuspid submitted to root canal treatment, with emphasis on the alternative technique employed. CASE DESCRIPTION: A 32 years old, male patient had suffered subluxation of teeth 12 and 13 and coronal fracture involving enamel and dentin, as well as pulp exposition, of tooth 14 because of a motorcycle accident. The man was given dental assistance and a semi-rigid splinting of teeth numbers 12 and 13 was carried out followed by the root canal treatment in a single visit on tooth no. 14. At 30-day follow-up pulp necrosis was detected in teeth 12 and 13 and the root canal treatment was implemented. The tooth 13 was 36 mm long and since the longest possible file (31 mm) was already in use, the cervical limit of the access cavity was considered as the reference point. CONCLUSION: This technique not only provided adequate disinfection, preparation and filling of the root canal, but it also allowed preservation of the remaining tooth structure.

OBJETIVO: Avaliar o preparo do canal radicular realizado por alunos de graduação com os sistemas manual e oscilatório, considerando o desgaste produzido nas paredes do mesmo, o tempo de trabalho e a opinião dos estudantes. METODOLOGIA: Foram utilizadas raízes mesiais de 20 molares inferiores humanos extraídos por indicação clínica. Vinte alunos de graduação realizaram o preparo de dois canais, um deles com o sistema manual e o outro com o sistema oscilatório, e posteriormente responderam a um questionário. O tempo foi registrado durante os preparos. Os dentes foram examinados por tomografia computadorizada antes e após o preparo. As imagens foram sobrepostas e as áreas de contorno demarcadas. Medidas lineares e da área de desgaste foram realizadas. RESULTADOS: Não houve diferença entre as técnicas quanto à medida linear de desgaste. A parede distal apresentou maior desgaste no terço cervical do que no médio em ambas as técnicas. A área total de desgaste foi maior no terço cervical do que no médio. Com relação ao tempo de preparo, não houve diferença estatisticamente significante entre as duas técnicas. CONCLUSÃO: O sistema oscilatório constitui-se em um recurso auxiliar para o preparo do canal radicular no ensino de graduação.

PURPOSE: To evaluate the preparation of root canals performed by undergraduate students using manual and automated devices, based on the amount of dentin removed from the canal walls, the time required for preparation, and students' opinions. METHODS: Mesial roots of 20 human mandibular molars extracted for clinical reasons were used in the experiment. Twenty undergraduate students prepared two canals each, one using the manual method and the other using an automated device; following root canal preparation, the students filled out a questionnaire. Time was recorded throughout the procedures. Teeth were scanned with computed tomography before and after preparation. Images were superimposed and measured for the amount and area of dentin removed. RESULTS: There was no difference between the use of manual and automated devices with regard to the amount of material removed. Distal walls presented a greater amount of material removed from the cervical third when compared with middle third in both techniques. There were no statistically significant differences between both techniques with regard to preparation time. CONCLUSION: The automated system represents an adequate alternative option as an auxiliary resource for undergraduate teaching in the preparation of root canals.

O objetivo do presente estudo foi avaliar a eficácia de diferentes técnicas na remoção de material obturador dos canais radiculares, através da tomografia computadorizada (TC). Sessenta raízes mesiais de molares inferiores humanos extraídos foram utilizadas. Os canais radiculares foram obturados e, após 6 meses, os dentes foram divididos aleatoriamente em 3 grupos, de acordo com a técnica de desobturação: Grupo A - instrumentação manual com limas tipo K; Grupo B - instrumentação oscilatória com limas tipo K acopladas a contra-ângulo NSK acionado por motor elétrico; e Grupo C - instrumentação rotatória com limas ProTaper associadas a contra-ângulo NSK acionado por motor elétrico. As imagens de TC foram feitas para avaliar o volume de material obturador encontrado no interior dos canais radiculares antes e após a desobturação. A região do material obturador foi demarcada nos dois momentos por um radiologista experiente e o volume foi calculado automaticamente pelo programa do TC. A partir do volume de material obturador inicial e remanescente de cada espécime o cálculo da porcentagem de material obturador removido. Os dados foram analisados pela análise de variância (ANOVA) e pelo teste qui-quadrado (?=0,05). A comparação das médias das porcentagens de material obturador removido não demonstrou diferença estatisticamente significante (p=0,36) entre os grupos. Analisando a associação do percentual de material obturador removido (baixo ou alto) com as diferentes técnicas de desobturação, através do teste Qui-quadrado, encontrou-se diferença estatisticamente significante (p=0,015), com maior número de casos com menos de 50% de seu material obturador removido (baixa remoção) no Grupo B. Em conclusão, nenhuma das técnicas estudadas foi capaz de remover completamente o material obturador do interior dos canais radiculares.

This study evaluated the efficiency of different techniques for removal of filling material from root canals, using computed tomography (CT). Sixty mesial roots from extracted human mandibular molars were used. Root canals were filled and, after 6 months, the teeth were randomly assigned to 3 groups, according to the root-filling removal technique: Group A - hand instrumentation with K-type files; Group B - reciprocating instrumentation with engine-driven K-type files; and Group C rotary instrumentation with engine-driven ProTaper system. CT scans were used to assess the volume of filling material inside the root canals before and after the removal procedure. In both moments, the area of filling material was outlined by an experienced radiologist and the volume of filling material was automatically calculated by the CT software program. Based on the volume of initial and residual filling material of each specimen, the percentage of filling material removed from the root canals by the different techniques was calculated. Data were analyzed statistically by ANOVA and chi-square test for linear trend (?=0.05). No statistically significant difference (p=0.36) was found among the groups regarding the percent means of removed filling material. The analysis of the association between the percentage of filling material removal (high or low) and the proposed techniques by chi-square test showed statistically significant difference (p=0.015), as most cases in group B (reciprocating technique) presented less than 50% of filling material removed (low percent removal). In conclusion, none of the techniques evaluated in this study was effective in providing complete removal of filling material from the root canals.

Coronal leakage is an important factor affecting the outcome of endodontic therapy. This study evaluated the microbial leakage (ML) and the apical inflammatory response (AIR) in dog's teeth after root canal filling with three endodontic sealers, post preparation and exposure to the oral environment, testing the hypothesis that there is a positive correlation between these two histological parameters (ML and AIR). Sixty-four root canals of 8 mongrel dogs were cleaned, shaped and randomly distributed into groups according to the sealer to be used: Sealer 26 (n=18); AH Plus (n=18); RoekoSeal (n=19); no sealer - control group (n=9). Root canals were filled by the lateral condensation technique. Post space preparation left 4 mm of filling material in the apical root third, and specimens were exposed to the oral environment for 90 days. The dogs were killed and jaw blocks were histologically processed using Brown & Brenn and HE staining techniques. ML and AIR were scored from 1 to 4. Results were analyzed statistically using ANOVA, Duncan's post-hoc test and Spearman's correlation. ML and AIR score means were: Sealer 26 - 2.44±0.98 and 2.50±0.70; AH Plus - 2.50±0.78 and 2.22±0.54; RoekoSeal - 1.84±0.95 and 2.63±0.83; Control - 2.56±1.23 and 3.11±0.60. Statistically significant differences in AIR scores were found between the AH Plus and control groups (p<0.05). Although RoekoSeal had the lowest ML means, and AH Plus, the lowest AIR means after 90-day exposure to the oral environment, no statistically significant differences were found between the three sealers under study, and no correlation was found between ML and AIR.

Objetivou-se comparar, in vitro, através de análise computadorizada de imagens radiográficas digitais, as alterações anatômicas promovidas nas paredes dentinárias de canais mésio-vestibulares com curvatura severa de molares inferiores por três técnicas endodônticas diferentes: Preparo Progressivo, Escalonada e Seriada. Foram selecionados 45 molares inferiores humanos extraídos, com curvaturas radiculares superiores a 25°, que foram divididos em três grupos para cada técnica estudada e subdivididos em três subgrupos de acordo com a posição da curvatura ao longo da raiz: cervical, mediana ou apical. Após cirurgia de acesso e odontometria, os canais foram preenchidos com contraste radiológico de sulfato de Bário a 100% e os dentes então foram radiografados por um sistema de radiografia digital direta, utilizando-se um aparato capaz de manter as amostras na mesma posição espacial nas diferentes tomadas radiográficas. Após a realização das técnicas endodônticas supracitadas, os dentes foram novamente preenchidos com o sulfato de Bário e radiografados nas mesmas condições anteriores. As imagens digitais pré e pós-operatórias foram então analisadas em dois programas computadorizados, o AutoCAD 2004 e o CorelDraw 10, para verificar, respectivamente, as áreas e as alterações horizontais ocorridas nas paredes internas e externas dos canais radiculares. Apesar de não ter havido diferenças significantes entre as técnicas na análise estatística, em uma análise descritiva a técnica do Preparo Progressivo mostrou-se mais regular, uniforme e eficaz.

The purpose of this study was to compare, in vitro, by means of computerized analysis of digital radiographic images, the anatomic alterations produced in the mandibular molar tooth dentinal walls of mesiobucal canals with severe curvature by three different endodontic techniques: Progressive Preparation, Staged and Serial Preparation. A selection was made of 45 extracted, human, mandibular molars, with root curvatures greater than 25°. They were divided into three groups for every technique studied, which were then sub-divided into three sub-groups in accordance with the position of the curvature along the root: cervical, median or apical. After access surgery and tooth length determination, the canals were filled with 100% Barium Sulphate radiological contrast and the teeth were then radiographed with a direct digital radiography system, using a special apparatus capable of keeping the samples in the same spatial position during the different radiographic takes. After the above-mentioned endodontic techniques had been performed, the teeth were again filled with Barium sulphate and were also radiographed under the same previously mentioned conditions. The pre- and post-operative digital images were then analyzed in two computerized programs, AutoCAD 2004 and CorelDraw 10, to assess, respectively, the areas and the horizontal alterations which occurred in the internal and external walls of the root canals. The results indicated that although no significant differences among the techniques were shown in the statistical analysis, in a descriptive analysis the Progressive Preparation technique was shown to be more regular, uniform and effective.

O objetivo deste trabalho foi verificar a correlação entre o grau de angulação e a posição das curvaturas radiculares, e a sua influência nos resultados comparativos entre os desempenhos das técnicas do Preparo Progressivo, Escalonada e Seriada. Os canais mésio-vestibulares de 70 dentes molares inferiores extraídos foram preenchidos com um contraste radiológico de sulfato de Bário a 100% e radiografados em um sistema de radiografia digital direta, em um aparato que garantia que as amostras ficassem sempre na mesma posição espacial. As imagens foram, então, analisadas no programa Coreldraw 10 (MicroSafe, RJ, Brasil) segundo dois critérios: os métodos de Berbert, Nishiyama¹ (1994) e de Schneider11 (1971) para determinação da posição e do ângulo das curvaturas radiculares, respectivamente. Estudou-se inicialmente a possibilidade de correlação entre essas duas variáveis. Os dentes foram, então, selecionados segundo a angulação (superior a 25 graus) e posição das curvaturas radiculares (cervical, mediana e apical) para a realização das técnicas endodônticas. Após os preparos, as amostras foram novamente radiografadas e as imagens sobrepostas para a comparação das áreas pré e pós-operatórias. A diferença entre elas mostrou a porcentagem de alargamento para cada técnica. Os resultados mostraram não existir correlação entre as angulações e as posições das curvaturas radiculares, e que as diferentes posições não interferem no desempenho das técnicas. A técnica do Preparo Progressivo mostrou maiores valores de alargamento para todos os grupos, independentemente da posição da curvatura radicular.

The aim of this study was to assess the correlation between the degree of angulation and the position of root curvatures and their influence on the comparative results between the performances of the Progressive, Staged and Serial Preparation Techniques. The mesiobucal canals of 70 extracted mandibular molars were filled with a radiological contrast of 100% Barium sulphate and radiographed with a direct digital radiographic system, in an apparatus that guarantees that the samples remain in the same spatial position at all times. The images were then analyzed in the Coreldraw 10 program (MicroSafe, RJ, Brasil) in accordance with two criteria: the methods of Berbert, Nishiyama¹ (1994) and Schneider11 (1971) to determine the position and the angle of the root curvatures, respectively. Initially, the possibility of correlation between these two variables was studied. The teeth were then selected according to angulation (greater than 25 degrees) and position of root curvatures (cervical, median and apical) in order to perform the endodontic techniques. After preparation, the samples were radiographed again and the images were superimposed in order to compare the pre- and post-operative areas. The difference between them showed the percentage of widening for each technique. The results showed that there was no correlation between the angulations and the root curvature positions, and that the different positions did not interfere in the performance of the techniques. The Progressive Preparation technique produced the highest widening values for all the groups, irrespective of the root curvature position.