Limas rotatorias de uso en Odontopediatría: revisión de la literatura / Rotary files for use in pediatric dentistry: Literature review

Introducción: Los dientes primarios juegan un importante papel en el crecimiento y desarrollo general de los niños, por lo que es necesario conservarlos hasta el momento de su recambio fisiológico. Cuando existe una afectación pulpar que compromete la vitalidad del diente, la pulpectomía se convierte en un reto para el odontopediatra debido a la compleja anatomía radicular de los dientes primarios. En esta revisión bibliográfica se darán a conocer diferentes sistemas de limas usados en odontopediatría, y así brindar una mirada actualizada de la instrumentación rotatoria al realizar pulpectomías en los molares primarios. Material y Método: se realizó una búsqueda bibliográfica en Pubmed y Web of Science de acuerdo con criterios de inclusión y exclusión previamente establecidos. Resultados: tras aplicar los criterios de inclusión y exclusión fueron seleccionados un total de 30 referencias bibliográficas de los últimos 15 años. Conclusión: las limas rotatorias pediátricas pueden considerarse alternativas seguras y más eficientes en la realización de pulpectomías en molares primarios, ya que se reduce el tiempo de tratamiento, se produce desbridamiento completo de los conductos y se mantiene la función del diente hasta su exfoliación. (AU)

Introduction: Primary teeth play an important role in the growth and development of children, so it is necessary to keep them until the moment of their physiological replacement. When there is a pulp involvement that compromises the vitality of the tooth, pulpectomy treatment becomes a challenge for the pediatric dentist due to the complex root anatomy of primary teeth. This review of the literature will present different file systems used in primary teeth and provide an updated look at rotary instrumentation when performing pulpectomies on primary molars. Material and Method: a bibliographic search was carried out in Pubmed and Web of Science according to previously established inclusion and exclusion criteria. Results: after applying the inclusion and exclusion criteria, a total of 30 bibliographic references from the last 15 years were selected. Conclusion: pediatric rotary files can be considered safe and more efficient alternatives in performing pulpectomies on primary molars, due to treatment time is reduced, complete debridement of the root canals is produced, and tooth function is maintained until exfoliation. (AU)

Limas rotatorias de uso en Odontopediatría: revisión de la literatura / Rotary files for use in pediatric dentistry: Literature review

Introducción: Los dientes primarios juegan un importante papel en el crecimiento y desarrollo general de los niños, por lo que es necesario conservarlos hasta el momento de su recambio fisiológico. Cuando existe una afectación pulpar que compromete la vitalidad del diente, la pulpectomía se convierte en un reto para el odontopediatra debido a la compleja anatomía radicular de los dientes primarios. En esta revisión bibliográfica se darán a conocer diferentes sistemas de limas usados en odontopediatría, y así brindar una mirada actualizada de la instrumentación rotatoria al realizar pulpectomías en los molares primarios. Material y Método: se realizó una búsqueda bibliográfica en Pubmed y Web of Science de acuerdo con criterios de inclusión y exclusión previamente establecidos. Resultados: tras aplicar los criterios de inclusión y exclusión fueron seleccionados un total de 30 referencias bibliográficas de los últimos 15 años. Conclusión: las limas rotatorias pediátricas pueden considerarse alternativas seguras y más eficientes en la realización de pulpectomías en molares primarios, ya que se reduce el tiempo de tratamiento, se produce desbridamiento completo de los conductos y se mantiene la función del diente hasta su exfoliación. (AU)

Introduction: Primary teeth play an important role in the growth and development of children, so it is necessary to keep them until the moment of their physiological replacement. When there is a pulp involvement that compromises the vitality of the tooth, pulpectomy treatment becomes a challenge for the pediatric dentist due to the complex root anatomy of primary teeth. This review of the literature will present different file systems used in primary teeth and provide an updated look at rotary instrumentation when performing pulpectomies on primary molars. Material and Method: a bibliographic search was carried out in Pubmed and Web of Science according to previously established inclusion and exclusion criteria. Results: after applying the inclusion and exclusion criteria, a total of 30 bibliographic references from the last 15 years were selected. Conclusion: pediatric rotary files can be considered safe and more efficient alternatives in performing pulpectomies on primary molars, due to treatment time is reduced, complete debridement of the root canals is produced, and tooth function is maintained until exfoliation. (AU)

Pulpectomies with Iodoform Versus Calcium Hydroxide-Based Paste: A Preliminary Randomised Controlled Clinical Trial

ABSTRACT Objective: To compare clinical and radiographical pulpectomy outcomes in primary teeth filled with different pastes. Material and Methods: The sample included thirty-eight teeth indicated for pulpectomy due to irreversible pulp inflammation or necrosis from thirty patients (2 to 9 years old). The first appointment comprised chemomechanical preparation (2.5% sodium hypochlorite), smear layer removal (6% citric acid), intracanal dressing and temporary restoration. Seven days later, teeth were randomly assigned to filling with iodoform (IP) or calcium hydroxide with zinc oxide (CHZO) based pastes and temporarily restored. Final restoration (composite resin) occurred at the 3rd appointment. Data from baseline, 6 and 12 months were analysed using descriptive and inferential statistics (p≤0.05). Results: The overall frequency of success was 63.6% (n=21), with no significant difference between groups (IP=62.5% n=10; CHZO=64.7% n=11, p=0.59). Multiradicular teeth, overfilled canals and teeth whose coronal restoration have been lost were significantly associated with failure (p=0.01, p=0.04 and p<0.001, respectively). Conclusion: After 12 months, both pastes showed similar outcomes and can be used as good options for pulpectomies in primary teeth. Moreover, tooth location, extent of the root canal filling, and integrity of final restoration during the follow-up influenced the outcome of pulpectomies.

Tempo e resultados biomecânicos da instrumentação endodôntica rotatória comparada a manual em protótipos de molares decíduos: estudo in vitro / Time and biomechanical results of rotary endodontic instrumentation compared to manual in deciduous molar prototypes: in vitro study

Objetivou-se elaborar um e-book aos cirurgiões-dentistas sobre as opções de sistema de instrumentação endodôntica para dentes decíduos e comparar os resultados biomecânicos de diferentes sistemas e seu tempo de preparo em protótipos de dentes decíduos por meio de uma análise em micro-CT. Para isso, foram realizados dois estudos. No primeiro, realizou-se uma busca bibliográfica em seis bases de dados por estudos laboratoriais e clínicos sobre protocolos de pulpectomia utilizando pelo menos uma técnica de instrumentação. Dados a respeito das características, cinemática, benefícios e orientações à cerca da utilização de acordo com as instruções dos fabricantes foram extraídos para elaboração do conteúdo teórico e diagramação do layout do e-book, confeccionado no programa Canva. Após finalizado, o mesmo foi avaliado por três pós-graduandos da Disciplina de Odontopediatria da FOUFRJ e as sugestões foram incorporadas. Elaborou-se o material intitulado ''Guia ilustrado de instrumentação endodôntica para dentes decíduos'' contendo 43 páginas, abordando 13 sistemas de instrumentação, com sequências ilustradas de protocolos para utilização. Para o segundo estudo foram utilizados 60 protótipos padronizados de segundos molares decíduos inferiores confeccionados em polímero transparente para avaliar os resultados biomecânicos da instrumentação com diferentes sistemas de limas. Foram utilizados os sistemas manual k-file e mecanizados ProTaper Nextâ (PTN), XP- Endoâ Shaper (XPS), XP- Endoâ Finisher (XPF), XP­Clean (XPC) e Sequence Baby file (SBF) (n= 10/cada). A instrumentação foi realizada por um único operador treinado e o tempo de utilização de cada sistema foi cronometrado. Realizouse a irrigação com um total de 16mL de soro fisiológico à 0,9% para cada canal instrumentado, associada a aspiração simultânea. Os protótipos foram escaneados antes e após da instrumentação através do micro-CT. A reconstrução foi padronizada os conjuntos de imagens iniciais e instrumentados foram registrados entre si. Alterações no volume do canal radicular, área não instrumentada, debris acumulados, volume de dentina removido e transporte do canal foram quantificados. Os dados foram tabulados no programa JAMOVI versão 1.6 e analisados através do teste Shapiro-Wilk para verificar a distribuição dos dados. Para distribuição normal foram realizados testes paramétricos e para aqueles que não seguiram a normalidade, testes não paramétricos foram utilizados, todos com um nível de significância de 5% (p<0,05). A instrumentação com sistemas mecanizados resultou em menos tempo de instrumentação (p< 0,001) do que com a k-file. A porcentagem de áreas não instrumentadas foi semelhante para todos os sistemas. O acúmulo de debris foi maior para K-file e XPS ao longo de todo o canal (p<0,05). Todos os grupos apresentaram aumento do volume do canal radicular após a instrumentação (p= 0,003) com valores mais elevados na lima K-file (p<0,05). A análise 3D revelou maior transporte da lima K-file. SBF e K-file apresentaram, respectivamente, o menor (0,01 ± 0,01 e 0,03 ± 0,04) e o maior (0,04 ± 0,05 e 0,32 ± 0,94) valor de transporte do canal nos protótipos. Diante das metodologias utilizadas, conclui-se que um material relevante e prático ficará disponível nas plataformas digitais da Disciplina de Odontopediatria da UFRJ, para livre acesso e ampla divulgação aos cirurgiões-dentistas. Além disso, com relação aos resultados de instrumentação mecânica, o SBF e o XPC resultaram em uma abordagem mais conservadora. A instrumentação mecânica pode levar à algum grau de transporte do canal e deixar partes das paredes do canal infectadas sem preparo mecânico. (AU)

The objective was to elaborate an e-book to dentists about the options of endodontic instrumentation system for primary teeth and to compare the biomechanical outcomes of the different systems and their instrumentation time in prototypes of primary teeth through micro-CT analysis. To this end, two studies were carried out. In developing the first, a bibliographic search was carried out in six databases. Laboratory and clinical studies with a pulpectomy protocol using at least one instrumentation technique were included. Data about features, kinematics, benefits, and guidelines on use according to the manufacturer's instructions were extracted to prepare the theoretical content and layout diagramming of the e-book using Canva software. Afterwards, it was evaluated by 3 postgraduate students of the Pediatric Dentistry Discipline-FOUFRJ and the suggestions for changes were incorporated. The product entitled 'Guia ilustrado de instrumentação endodôntica para dentes decíduos' contains 43 pages covering 13 instrumentation systems and illustrated sequence of protocols use for each. The second consists of 60 standardized prototype teeth of mandibular second primary molars made with transparent polymer to evaluate the outcomes of biomechanical instrumentation of different systems. Manual k-file, ProTaper Nextâ (PTN), XP-Endoâ Shaper (XPS), XP-Endoâ Finisher (XPF), XP ­ Clean (XPC) and Sequence Baby file (SBF) (n= 10/each) were used. The specimen instrumentation was performed by a single trained and the time spend was recorded. Irrigation was performed with a total of 16mL of 0.9% saline solution for each instrumented canal and simultaneous aspiration. The prototypes were scanned before and after the instrumentation using micro-CT. In addition, the reconstruction was standardized and initial and instrumented image sets were registered with each other. Next, changes in root canal volume, noninstrumented areas, accumulated debris, removed dentin volume and canal transportation were quantified. Data were tabulated in the JAMOVI program version 1.6 and analyzed using the Shapiro-Wilk test to verify the data distribution. For normal distribution, parametric tests were performed and that did not follow normality, nonnormal tests were used, all with a significance level of 5% (p<0.05). Instrumentation with rotary files resulted in less time-consuming (p <0.001) than manual k-file. The percentage of non-instrument areas were similar for all systems. Accumulated debris was higher for K-file and XPS along the entire canal. All groups showed an increase in root canal volume after instrumentation (p= 0.003) with higher values in K-file (p <0.05). 3D analysis revealed greater transportation in K-file. SBF and K-file showed, respectively, the lowest (0.01± 0.01 and 0.03 ± 0.04) and highest (0.04 ± 0.05 and 0.32 ± 0.94) canal transportation value in the prototypes. Given the methodology applied, it was concluded that: the didactic material will be available on the digital platforms of Pediatric Dentistry at UFRJ for free access and widespread. From the overall mechanical instrumentation outcomes, the SBF and XPC resulted in a more conservative approach. Mechanical instrumentation may lead transportation and leave preparation. (AU)

Do Different Proportions of Antibiotics in the CTZ Paste Interfere with the Antimicrobial Action? In Vitro Study

Abstract Objective: To evaluate the antimicrobial action of the CTZ paste in three different proportions by diffusion in agar with the microorganisms: Enterococcus faecalis,Escherichia coli, and Candida albicans. Material and Methods: Three different proportions of antibiotics were tested: GROUP A - CTZ paste in the ratio of 33.33% chloramphenicol + 33.33% tetracycline + 33.33% zinc oxide, mixed with 2 drops of eugenol (1:1:1 ratio); GROUP B - CTZ paste in the proportion of 25% chloramphenicol + 25% tetracycline + 50% zinc oxide, mixed with 2 drops of eugenol (1: 1: 2 ratio); GROUP C - CTZ paste with 13% chloramphenicol + 13% tetracycline + 74% Zinc Oxide, mixed with 2 drops of eugenol (1:1:6 ratio); PC GROUP - Positive Control (0.12% Chlorhexidine); and NC GROUP - Negative Control (0.9% Saline solution). Data were analyzed through descriptive statistics (means and standard deviation). The one-way ANOVA and Tukey's test were used, with a significance level of 5% Results: No statistical differences for Enterococcus faecalis between groups A, B, and C (p = 0.1986) were found. There were statistical differences for Escherichia coli between groups B and C (p = 0.029), and for Candida albicans between groups A and C (p = 0.006). Groups A, B, and C had significant differences with both Positive and Negative Controls for all the microorganisms Conclusion: The three different ratios of CTZ paste showed antimicrobial efficacy against Enterococcus faecalis,Escherichia coli, and Candida albicans microorganisms.

Endodontic Treatment of Primary Molars with Antibiotic Paste: A Report of 38 Cases.

OBJECTIVE: This study presents 38 cases of primary molars with necrotic pulps treated with antibiotics-based paste. CASE REPORT: The technique consisted of necrotic tissue removal of the pulp chamber, using spoons excavators and low speed drills. Pulp cavity was washed with saline solution and dried with sterile cotton balls. Then an antibiotic paste composed of chloramphenicol, tetracycline, zinc oxide and eugenol - CTZ paste - was inserted at the entrance of root canals. Patients were evaluated clinically and radiographically at different times. The criteria that defined clinical success were the lack of periapical abscess and mobility compatible with chronological age. Radiographic assessments consisted in absence of radiolucency in the region of root bifurcation and pathological bone resorption. CONCLUSION: There were 100% and 93% of clinical and radiographic success, respectively. The results suggest that the CTZ paste is an optional therapy for pulp of primary molars.

Comparison of pulp stump wounds created by profile rotary root canal instruments and small-diameter fine diamond burs.

INTRODUCTION: The aim of this investigation was to evaluate and compare the pulp stump wounds created by the following root canal instruments: ProFile rotary files and small-diameter fine diamond burs. METHODS: Extracted mandibular premolars from adult patients with vital pulps and fully formed root canals were collected and stored in formalin. Within 48 hours of extraction, the periapical tissue was fixated to the root with a double coating of ethyl cyanoacrylate, and the pulp chambers were accessed with a #4 round carbide bur and high-speed handpiece in a traditional fashion. The pulp tissue of 10 specimens per group was extirpated at a level approximately 5 mm from the apex by using standard endodontic techniques. The specimens were then examined at ×100 magnification under a digital microscope. Grading criteria were developed, and the wounds were scored. RESULTS: Wounds created by diamond burs were significantly smoother that those created by ProFile rotary files; the mean wound score for diamond burs was 1.4 versus a mean wound score of 3 for ProFiles. After the author's scoring of the wounds, 2 endodontist graders were shown photos of each specimen in a double-blind fashion and instructed to score each specimen as being smooth or rough. To validate the developed scoring system and remove potential observer bias of the author, the data from the double-blind observations were used to complete a cross-tabulation for a Cohen kappa test. CONCLUSIONS: Kappa values demonstrated substantial inter-rater agreement for both groups.

Effect of working length measurement by electronic apex locator or digital radiography on postoperative pain: a randomized clinical trial.

INTRODUCTION: The aim of this study was to evaluate the effect of working length determination methods, electronic apex locator and digital radiography, on postoperative pain. METHODS: Two hundred twenty patients with asymptomatic single-rooted vital teeth were randomly assigned to 2 groups according to the method used for working length determination, the radiographic group and the electronic apex locator group. After working length determination, chemomechanical preparation was performed in a crown-down technique with ProTaper instruments. A master cone radiograph was taken. Canals were obturated with gutta-percha and sealer by using a lateral compaction technique. Postoperative pain was assessed after 4, 6, 12, 24, and 48 hours by using a 4-point pain intensity scale. In addition, patients were asked to record the number of days necessary to achieve complete pain resolution. RESULTS: Postoperative pain during the 4-hour to 48-hour interval studied was not significantly different (P > .05) between groups. The mean times for pain dissipation in the radiographic and electronic apex locator groups were 3.37 ± 2.79 and 3.88 ± 3.34 days, respectively. The difference between groups was not statistically significant (P > .05). CONCLUSIONS: There is no difference in postoperative pain between working length measurement methods by using an electronic apex locator or digital radiography. The reduced exposure to radiation by using apex locator may be a factor that influences a dentist's decision to choose the electronic apex locator over radiography.

Effectiveness of three instrumentation systems to remove Enterococcus faecalis from root canals.

AIM: To assess the effectiveness of three systems of mechanical preparation to reduce Enterococcus faecalis within root canals. METHODOLOGY: Twenty-four human single-rooted canine teeth were standardized to a length of 17 mm and the canal contents removed using a size 20 K-file, as the last apical file. After irrigation and sterilization, the canals were contaminated with E. faecalis and incubated for 21 days at 37 °C with 5% CO(2). Then, the teeth were divided into three groups for mechanical preparation with: ProTaper rotary system, ProTaper manual system and manual K-files. Samples of the root canal contents, before and after the debridement, were collected with sterile paper points for 1 min. Then, the samples were diluted and plated in Brain Heart Infusion (BHI) agar. The colony-forming units were counted and the percentage reduction calculated. The reduction and log CFU mL(-1) were compared between groups using Wilcoxon nonparametric test and two-way analysis of variance, respectively. RESULTS: There was a significant reduction in the number of CFU/mL (P = 0.000) before and after debridement for all the systems used. However, there was no significant difference between the systems. CONCLUSION: All the three instrumentation systems reduced E. faecalis counts to a similar degree.

Anesthetic efficacy of four percent articaine for pulpal anesthesia by using inferior alveolar nerve block and buccal infiltration techniques in patients with irreversible pulpitis: a prospective randomized double-blind clinical trial.

INTRODUCTION: The study was designed as a randomized double-blind trial to evaluate the anesthetic efficacy of 4% articaine with 1:100,000 epinephrine in inferior alveolar nerve block (IANB) and infiltration anesthetic techniques to anesthetize mandibular molars with irreversible pulpitis. METHODS: The study was composed of 2 test arms and 1 control arm. Subjects in the test arms received either a standard IANB or a buccal infiltration (B Infil) of 4% articaine with 1:100,000 epinephrine, whereas the subjects in the control arm received a standard IANB of 2% lidocaine with 1:100,000 epinephrine. Subject's self-reported pain response was recorded on Heft Parker Visual Analogue Scale after local anesthetic administration during access preparation and pulp extirpation. RESULTS: For statistical analysis Pearson χ(2), Student's paired t test, 1-way analysis of variance, and Friedman tests showed no significant difference in success rates among the 3 arms of the trial. CONCLUSIONS: Although B Infil and IANB of 4% articaine were equally effective, B Infil can be considered a viable alterative in IANB for pulpal anesthesia in mandibular molars with irreversible pulpitis.

Comparison between rotary and manual techniques on duration of instrumentation and obturation times in primary teeth.

OBJECTIVE: The aim of this study was to compare the duration of instrumentation and obturation times and quality of root canal filling between rotary and manual instrumentation techniques in primary teeth. STUDY DESIGN: A randomized, controlled clinical trial was performed that included deciduous teeth with pulp necrotic. Forty necrotic teeth were included; 20 were instrumented with a rotary technique (experimental group) and 20 with a manual technique (control group). The time taken for instrumentation and for obturation were recorded in minutes, and the quality of the root canal filling was recorded as optimal, under-filled, or overfilled. RESULTS: The use of the rotary technique diminished the time of instrumentation to 63% and time of obturation to 68%, and it improved the quality of the root canalfilling. CONCLUSION: The use of rotary instruments in the pulpectomy of primary molars represents a promising technique; the time is significantly reduced.

Influence of cervical preflaring on determination of apical file size in mandibular molars: SEM analysis.

This study investigated the influence of cervical preflaring with different rotary instruments on determination of the initial apical file (IAF) in mesiobuccal roots of mandibular molars. Fifty human mandibular molars whose mesial roots presented two clearly separated apical foramens (mesiobuccal and mesiolingual) were used. After standard access opening and removal of pulp tissue, the working length (WL) was determined at 1 mm short of the root apex. Five groups (n=10) were formed at random, according to the type of instrument used for cervical preflaring. In group 1, the size of the IAF was determined without preflaring of the cervical and middle root canal thirds. In groups 2 to 5, preflaring was performed with Gates-Glidden drills, ProTaper instruments, EndoFlare instruments and LA Axxes burs, respectively. Canals were sized manually with K-files, starting with size 08 K-files, inserted passively up to the WL. File sizes were increased until a binding sensation was felt at the WL and the size of the file was recorded. The instrument corresponding to the IAF was fixed into the canal at the WL with methylcyanoacrylate. The teeth were then sectioned transversally 1 mm short of the apex, with the IAF in position. Cross-sections of the WL region were examined under scanning electron microscopy and the discrepancies between canal diameter and the diameter of IAF were calculated using the tool "rule" (FEG) of the microscope's proprietary software. The measurements (microm) were analyzed statistically by Kruskal-Wallis and Dunn's tests at 5% significance level. There were statistically significant differences among the groups (p<0.05). The non-flared group had the greatest discrepancy (125.30 +/- 51.54) and differed significantly from all flared groups (p<0.05). Cervical preflaring with LA Axxess burs produced the least discrepancies (55.10 +/- 48.31), followed by EndoFlare instruments (68.20 +/- 42.44), Gattes Glidden drills (68.90 +/- 42.46) and ProTaper files (77.40 +/- 73.19). However, no significant differences (p>0.05) were found among the rotary instruments. In conclusion, cervical preflaring improved IAF fitting to the canals at the WL in mesiobuccal roots of maxillary first molars. The rotary instruments evaluated in this study did not differ from each other regarding the discrepancies produced between the IAF size and canal diameter at the WL.

Endodontics in primary molars using ultrasonic instrumentation.

PURPOSE: The purpose of this study, which is a series of consecutive case reports, was to describe and evaluate the protocol used in the treatment of pulpal necrosed of primary molars, used by the dental service of Social Support Foundation of the Moinhos de Vento Hospital, Porto Alegre, RS, Brazil. METHODS: Eighteen primary molars in 15 children, ranging from 4 to 10 years of age, were endodontically treated using ultrasonic instrumentation. RESULTS: Clinical and radiographic controls showed a success rate of 94%, considering an evaluation time of 14.1+/-6.3 months. CONCLUSIONS: The use of ultrasonic instrumentation in primary molars with pulpal necrosis succeeded in reducing appointment time and showed a high success rate.

Study of root canal accessibility in human primary molars.

The aim of the present study was to provide a general scheme for pulpectomy of primary molars that may be useful for decision-making about negotiation of root canals and selection of appropriate instruments. A total of 160 vital primary molars in 85 patients (40 males, 45 females) aged 4-6 years were selected. After taking primary radiographs, local anesthesia was induced, and the teeth were isolated using a rubber dam. Canal accessibility index (CAI) and tooth accessibility index (TAI) were calculated according to initial file size. Mandibular first molars had either three canals (79.2%) or four canals (20.8%), and all second molars had four canals. Maxillary first molars had three canals and second molars had either three canals (70.9%) or four canals (29.1%). Lower accessibility of the mandibular first molar distobuccal root accounted for the lower accessibility of these teeth in comparison with mandibular second molars. While three-canal maxillary second molars were more accessible due to the lower accessibility of the distobuccal canal of the maxillary first molar, poor accessibility of the distal canal in four-canal second molars was responsible for the difficult accessibility of these teeth. In conclusion, it seems that the accessibility of a single canal in each tooth determines the difficulty of accessibility for any given tooth. Moreover, while primary second molars are more accessible than first molars, all of them are negotiable.

Influence of cervical preflaring on determinationof apical file size in mandibular molars: SEM analysis

This study investigated the influence of cervical preflaring with different rotary instruments on determination of the initial apical file (IAF) in mesiobuccal roots of mandibular molars. Fifty human mandibular molars whose mesial roots presented two clearly separated apical foramens (mesiobuccal and mesiolingual) were used. After standard access opening and removal of pulp tissue, the working length (WL) was determined at 1 mm short of the root apex. Five groups (n=10) were formed at random, according to the type of instrument used for cervical preflaring. In group 1, the size of the IAF was determined without preflaring of the cervical and middle root canal thirds. In groups 2 to 5, preflaring was performed with Gates-Glidden drills, ProTaper instruments, EndoFlare instruments and LA Axxes burs, respectively. Canals were sized manually with K-files, starting with size 08 K-files, inserted passively up to the WL. File sizes were increased until a binding sensation was felt at the WL and the size of the file was recorded. The instrument corresponding to the IAF was fixed into the canal at the WL with methylcyanoacrylate. The teeth were then sectioned transversally 1 mm short of the apex, with the IAF in position. Cross-sections of the WL region were examined under scanning electron microscopy and the discrepancies between canal diameter and the diameter of IAF were calculated using the tool "rule" (FEG) of the microscope's proprietary software. The measurements (µm) were analyzed statistically by Kruskal-Wallis and Dunn's tests at 5 percent significance level. There were statistically significant differences among the groups (p<0.05). The non-flared group had the greatest discrepancy (125.30 ± 51.54) and differed significantly from all flared groups (p<0.05). Cervical preflaring with LA Axxess burs produced the least discrepancies (55.10 ± 48.31), followed by EndoFlare instruments (68.20 ± 42.44), Gattes Glidden drills (68.90 ± 42.46)...

Este estudo investigou a influência do alargamento cervical feito com diferentes instrumentos rotatórios na determinação do instrumento apical inicial (IAI) das raizes mésio-vestibulares de molares inferiores. Foram utilizados 50 molares inferiores cujas raízes mesiais apresentavam dois forames apicais nitidamente separados (mésio-vestibular e mésio-lingual). Após o acesso à câmara pulpar de forma convencional e remoção do tecido pulpar, o comprimento de trabalho foi definido a 1 mm do ápice radicular. Os dentes foram divididos aleatoriamente em cinco grupos (n= 10) de acordo com o tipo de instrumento utilizado no alargamento cervical. No grupo 1, o IAI foi definido sem o prévio alargamento dos terços médio e cervical das raízes. Nos grupos 2 a 5, o terço cervical e médio do canal radicular foi alargado com as brocas de Gates-Glidden, instrumentos Pro Taper, Endo Flare e brocas LA Axxes, respectivamente. A determinação do IAI foi realizada manualmente com limas tipo K em ordem crescente de diâmetro a partir da lima 08 até se chegar ao instrumento que permitisse ao operador ter a sensação tátil do mesmo estar firmemente ajustado ao CRT. O instrumento que correspondeu ao IAI foi fixado no interior do canal radicular com cianocrilato de metila. Com o IAI posicionado, os dentes foram seccionados transversalmente até 1 mm do ápice. As seções transversais do CRT foram observadas através da microscopia eletrônica de varredura e os desajustes entre o diâmetro do canal e o diâmetro do IAI foram calculados com a função "régua" (FEG) do software do próprio microscópio. Os resultados foram avaliados estatisticamente pelo testes de Kruskal-Wallis e Dunn ao nível de significância de 5 por cento. Houve diferenças estatisticamente significantes entre os grupos (p<0,05). O grupo sem alargamento apresentou o maior desajuste (125,30 ±51,54) e diferiu significativamente dos demais grupos (p<0,05). O alargamento cervical com as brocas LA Axxess apresentou...

Effect of Waterlase laser retrograde root-end cavity preparation on the integrity of root apices of extracted teeth as demonstrated by light microscopy.

Most endodontists use ultrasonic instruments for retrograde root-end cavity preparations even though they have been found to produce cracks. In this laboratory study, thirty-six randomly chosen roots had root-end cavity preparations made with the Waterlase laser and only one questionable intra-canal crack was found. It was concluded that the Waterlase laser when used to make endodontic root-end cavity preparations produces either no cracks, or a very low percentage (2.8%) of cracks.

Impact of a biological barrier in pulpectomies of primary molars.

PURPOSE: The purpose of this in vitro study was to determine whether placement of a resorbable collagen barrier at the apical one third of the root canal could prevent extrusion of pulpectomy filling material. METHODS: Twenty-five extracted primary mandibular second molars, with at least two thirds of root length remaining, were used. The apical third of each root was covered with utility wax, and teeth were embedded in acrylic. Carious tooth structure was removed, crowns were reduced to a flat surface, and canals were accessed and preflared. Working lengths were established by reducing file lengths 2 mm short of the anatomic apex. Cleaning and shaping was performed using hand and rotary files, and canals were irrigated with sodium hypochlorite and dried with paper points. CollaCote was randomly packed into 1 of 2 prepared canals, and obturation was performed with Vitapex. Postoperative radiographs were independently evaluated for the presence of overfilling, and data were statistically analyzed using chi-square analysis. RESULTS: Overfilling was observed in 16% (4/25) of the CollaCote treated canals and in 42% (10/24) of canals when no barriers were used (P = .047). CONCLUSION: The application of CollaCote at the apical one third of the canals did not completely prevent, but did significantly decrease, the risk for overfilling in primary molars.