Physicomechanical Properties of Tertiary Monoblock in Endodontics: A Systematic Review and Meta-analysis.

Introduction: A systematic review and meta-analysis were conducted to evaluate the physicomechanical properties of tertiary monoblock obturation with different obturation techniques. Methods and Materials: PubMed (MEDLINE), Web of Science, Scopus, the Cochrane Library, LILACS, IBECS, and BBO were searched time. PICO question was: "In extracted human teeth (Population), does tertiary monoblock obturation (Intervention) have superior physicomechanical properties (Outcome) compared to conventional obturation systems (Comparison)?". Statistical analyses for push-out bond strength were performed with RevMan software by comparing the mean differences of each study, with a 95% confidence interval. Inverse variance was used as statistical method, random-effects models as analysis model, and heterogeneity between studies was assessed by Cochran's Q test and I2 statistic (P <0.05). Results: Of 2162 studies retrieved, 31 were included in this review for "Study Characteristics". Ten studies were included in the meta-analysis. Analysis demonstrated that conventional obturation had significantly higher push-out bond strength than tertiary monoblock obturation (P <0 .01), with a mean difference of -1.00 (95% CI, -1.41 to -0.58; I2=100%). Subgroups using single-cone and cold lateral condensation techniques showed significantly lower push-out bond strength for tertiary monoblock obturation (P <0.01), respectively with a mean difference of -0.09 (95% CI, -1.13 to -0.67; I2=97%) and of -1.97 (95% CI, -3.19 to -0.75; I2=100%). The warm vertical compaction subgroup showed no statistically significant difference between tertiary monoblock and conventional systems (P =0.13), with a mean difference of 0.49 (95% CI, -0.14 to 1.12; I2=10%). Conclusion: Tertiary monoblock systems have a push-out bond strength similar to conventional systems when used with warm vertical compaction.

Cone-beam and micro-computed tomography for the assessment of root canal morphology: a systematic review.

This study presents an overview of the accuracy of cone beam computed tomography (CBCT) compared with micro-computed tomography (µCT) in the assessment of root canal morphology of extracted human permanent teeth. A database search in PubMed, PubMed Central, Embase, Scopus, Opengrey, Scielo and Virtual Health Library was conducted which compared root canal morphology of extracted human permanent teeth on the accuracy of CBCT with µCT. In accordance with PRISMA statement guidelines, data were extracted on study characteristics, target mediators, sampling and assay techniques and the parameters associated with obtaining the image and ability to identify the root canal morphology. Amongst 2734 records, ten fulfilled the inclusion criteria. Four studies compared the accuracy of CBCT and µCT in the assessment of root canal morphology using Vertucci's classification, with at least one CBCT group or subgroup of each study presented high agreement compared to the µCT. Six studies assessed more detailed root canal morphology, including two articles that found a lack of agreement between these imaging systems. Risk of bias was deemed low in three studies, moderate in four and high in three. CBCT can be as accurate as µCT in the assessment of several morphological features of extracted human permanent teeth; however there are some exceptions related to the more detailed morphological aspects. Voxel size likely influences the ability to detect these features, though the different aspects of exposure setting used in studies components may be confounding factors. CBCT may be considered for the assessment of root canal morphology ex-vivo.

The Contribution of the Brazilian Dental Journal to the Brazilian Scientific Research over 30 Years.

The Brazilian Dental Journal (BDJ) was officially launched in 1990, stimulated by the courage and boldness of researchers dedicated to teaching and research in dentistry. The journal was conceived in a worldwide coverage and universal language to allow publication of the results of Brazilian studies, which otherwise would not be accessible to the scientific dental community. In the year we celebrate the thirtieth anniversary of BDJ, this article presents a brief overview of Brazilian dental research and a bibliometric analysis of the articles published in this journal as a contribution to our readers and fellow researchers. The purpose was to identify the mot frequent categories of study, the most published areas of dentistry and BDJ's top 50 most-cited articles in the Scopus and Google Scholar databases. A search was performed on all BDJ online issues published from 1990 to 2019. In this period, BDJ published 1,710 articles. Based on their distribution by category of study, 557 articles were in the basic research/dental materials area, 527 in the basic research/biology area and 280 in the clinical research area. Eight articles were cited more than 100 times in the Scopus database and 266 times in the Google Scholar database. Endodontics was the most published area. This overview of BDJ production over those 30 years allows establishing a profile of the characteristics, impact and trends of the published studies, as well as the journal's contribution to the top 50 most-cited articles in the Scopus and Google Scholar databases.

Cone-beam and micro-computed tomography for the assessment of root canal morphology: a systematic review

Abstract This study presents an overview of the accuracy of cone beam computed tomography (CBCT) compared with micro-computed tomography (μCT) in the assessment of root canal morphology of extracted human permanent teeth. A database search in PubMed, PubMed Central, Embase, Scopus, Opengrey, Scielo and Virtual Health Library was conducted which compared root canal morphology of extracted human permanent teeth on the accuracy of CBCT with μCT. In accordance with PRISMA statement guidelines, data were extracted on study characteristics, target mediators, sampling and assay techniques and the parameters associated with obtaining the image and ability to identify the root canal morphology. Amongst 2734 records, ten fulfilled the inclusion criteria. Four studies compared the accuracy of CBCT and μCT in the assessment of root canal morphology using Vertucci's classification, with at least one CBCT group or subgroup of each study presented high agreement compared to the μCT. Six studies assessed more detailed root canal morphology, including two articles that found a lack of agreement between these imaging systems. Risk of bias was deemed low in three studies, moderate in four and high in three. CBCT can be as accurate as μCT in the assessment of several morphological features of extracted human permanent teeth; however there are some exceptions related to the more detailed morphological aspects. Voxel size likely influences the ability to detect these features, though the different aspects of exposure setting used in studies components may be confounding factors. CBCT may be considered for the assessment of root canal morphology ex-vivo.

Experimental Resin-Based Monoblock Endodontic Obturation System.

OBJECTIVE: The aim of the present study was to characterize a novel resin-based monoblock endodontic obturation system consisting of a polymeric cone and a resin-based endodontic sealer. METHODS: The preliminary tests performed for the experimental cone were as follows: cohesive strength, dimensional stability, standardization of the diameter and taper, calcium ion release, and radiopacity, for the characterization of the experimental sealer, film thickness and flow tests were performed. Tests were performed according to the American National Standards Institute/American Dental Association (ANSI/ADA) Standards Nos. 57 and 78. The experimental cone was compared to gutta-percha, whereas the experimental sealer was compared to AH Plus. Data were analyzed by Student's t-test (α = 0.05). RESULTS: The experimental cone had superior values for cohesive strength and dimensional stability compared to gutta-percha. Regarding calcium ion release, the experimental system continued to release calcium ions after 30 days. Film thickness was similar for both endodontic sealers; conversely, the experimental resin-based sealer achieved higher values for flow compared to AH Plus. CONCLUSION: The experimental resin-based monoblock obturation system fully met the requirements of the ANSI/ADA Standard No. 78 and the ANSI/ADA Standard No. 57, except for radiopacity. Considering this, further studies are still needed to evaluate other radiopacifiers and the effect of their incorporation on the physicochemical properties of this novel resin-based monoblock endodontic obturation system.

Demetallization of Enterococcus faecalis biofilm: a preliminary study.

Objectives To determine the concentration of calcium, iron, manganese and zinc ions after the application of chelator to Enterococcus faecalis biofilms. Material and Methods Fifty bovine maxillary central incisors were prepared and inoculated with E. faecalis for 60 days. The following were used as irrigation solutions: 17% EDTA (pH 3, 7 and 10), 2.5% sodium hypochlorite (NaOCl) combined with 17% EDTA (pH 3, 7 and 10), distilled water (pH 3, 7 and 10), and 2.5% NaOCl. Each solution was kept in the root canal for five minutes. Fifteen uncontaminated root canals were irrigated with 17% EDTA (pH 3, 7 and 10). Six teeth were used as bacterial control. The number of calcium, iron, manganese and zinc ions was determined using flame atomic absorption spectrometry. Mean ± standard deviation (SD) values were used for descriptive statistics. Results Calcium chelation using 17% EDTA at pH 7 was higher than at pH 3 and 10, regardless of whether bacterial biofilm was present. The highest concentration of iron occurred at pH 3 in the presence of bacterial biofilm. The highest concentration of manganese found was 2.5% NaOCl and 17% EDTA at pH 7 in the presence of bacterial biofilm. Zinc levels were not detectable. Conclusions The pH of chelating agents affected the removal of calcium, iron, and manganese ions. The concentration of iron ions in root canals with bacterial biofilm was higher after the use of 17% EDTA at pH 3 than after the use of the other solutions at all pH levels.

Demetallization of Enterococcus faecalis biofilm: a preliminary study

Abstract Objectives To determine the concentration of calcium, iron, manganese and zinc ions after the application of chelator to Enterococcus faecalis biofilms. Material and Methods Fifty bovine maxillary central incisors were prepared and inoculated with E. faecalis for 60 days. The following were used as irrigation solutions: 17% EDTA (pH 3, 7 and 10), 2.5% sodium hypochlorite (NaOCl) combined with 17% EDTA (pH 3, 7 and 10), distilled water (pH 3, 7 and 10), and 2.5% NaOCl. Each solution was kept in the root canal for five minutes. Fifteen uncontaminated root canals were irrigated with 17% EDTA (pH 3, 7 and 10). Six teeth were used as bacterial control. The number of calcium, iron, manganese and zinc ions was determined using flame atomic absorption spectrometry. Mean ± standard deviation (SD) values were used for descriptive statistics. Results Calcium chelation using 17% EDTA at pH 7 was higher than at pH 3 and 10, regardless of whether bacterial biofilm was present. The highest concentration of iron occurred at pH 3 in the presence of bacterial biofilm. The highest concentration of manganese found was 2.5% NaOCl and 17% EDTA at pH 7 in the presence of bacterial biofilm. Zinc levels were not detectable. Conclusions The pH of chelating agents affected the removal of calcium, iron, and manganese ions. The concentration of iron ions in root canals with bacterial biofilm was higher after the use of 17% EDTA at pH 3 than after the use of the other solutions at all pH levels.

Micro-CT Evaluation of Root and Canal Morphology of Mandibular First Premolars with Radicular Grooves.

The aim of this study was to evaluate morphological features of 70 single-rooted mandibular first premolars with radicular grooves (RG) using micro-CT technology. Teeth were scanned and evaluated regarding the morphology of the roots and root canals as well as length, depth and percentage frequency location of the RG. Volume, surface area and Structure Model Index (SMI) of the canals were measured for the full root length. Two-dimensional parameters and frequency of canal orifices were evaluated at 1, 2, and 3 mm levels from the apical foramen. The number of accessory canals, the dentinal thickness, and cross-sectional appearance of the canal at different root levels were also recorded. Expression of deep grooves was observed in 21.42% of the sample. Mean lengths of root and RG were 13.43 mm and 8.5 mm, respectively, while depth of the RG ranged from 0.75 to 1.13 mm. Mean canal volume, surface area and SMI were 10.78 mm3, 58.51 mm2, and 2.84, respectively. Apical delta was present in 4.35% of the sample and accessory canals were observed mostly at the middle and apical thirds. Two-dimensional parameters indicated an oval-shaped cross-sectional appearance of the root canal with a high percentage frequency of canal divisions (87.15%). Canal configuration type V (58.57%) was the most prevalent. C-shaped configuration was observed in 13 premolars (18.57%), whereas dentinal thickness ranged from 1.0 to 1.31 mm. Radicular grooves in mandibular first premolars was associated with the occurrence of several anatomical complexities, including C-shaped canals and divisions of the main root canal.

Effect of different diode laser wavelengths on root dentin decontamination infected with Enterococcus faecalis.

The objective of this study was to evaluate the antibacterial effect and the ultrastructural alterations of diode laser with different wavelengths (808nm and 970nm) and its association with irrigating solutions (2.5% sodium hypochlorite and 2% chlorhexidine) in root dentin contaminated by a five days biofilm. Thirteen uniradicular teeth were sectioned into 100 dentin intraradicular blocks. Initially, the blocks were immersed for 5min in 17% EDTA and washed with distilled water for 5min, then samples were sterilized for 30min at 120°C. The dentin samples were inoculated with 0.1mL of E. faecalis suspension in 5mL BHI (Brain Heart Infusion) and incubated at 37°C for 5days. After contamination, the specimens were distributed into ten groups (n=10) according to surface treatment: GI - 5mL NaOCl 2.5%, GII - 5mL NaOCl 2.5%+808nm diode (0.1W for 20s), GIII - 5mL NaOCl 2.5%+970nm diode (0.5W for 4s), GIV - 808nm diode (0.1W for 20s), GV - 970nm diode (0.5W for 4s), GVI - CHX 2%, GVII - CHX 2%+808nm diode (0.1W for 20s), GVIII - CHX 2%+970nm diode (0.5W for 4s), GIX - positive control and GX - negative control. Bacterial growth was analyzed by turbidity and optical density of the growth medium by spectrophotometry (nm). Then, the specimens were processed for analysis ultrastructural changes of the dentin surface by SEM. The data was subject to the One-way ANOVA test. GI (77.5±12.1), GII (72.5±12.2), GIII (68.7±8.7), GV (68.3±8.7), GVI (62.0±5.5) and GVII (67.5±3.3) were statistically similar and statistically different from GIV (58.8±25.0), GVIII (59.2±4.0) and control groups (p<0.05). SEM analysis showed a modified amorphous organic matrix layer with melted intertubular dentin when dentin samples were irradiated with 970nm diode laser; erosion of the intertubular dentin in blocks submitted to 808nm diode laser irradiation; and an increased erosion of the intertubular dentin when 2.5% NaOCl was associated to the different wavelengths lasers. All the therapeutic protocols were able to reduce the bacterial contingent in dentin blocks, and the association of diode laser and solutions did not significantly improve the reduction of the bacterial contingent.

Micro-CT Evaluation of Root and Canal Morphology of Mandibular First Premolars with Radicular Grooves

Abstract The aim of this study was to evaluate morphological features of 70 single-rooted mandibular first premolars with radicular grooves (RG) using micro-CT technology. Teeth were scanned and evaluated regarding the morphology of the roots and root canals as well as length, depth and percentage frequency location of the RG. Volume, surface area and Structure Model Index (SMI) of the canals were measured for the full root length. Two-dimensional parameters and frequency of canal orifices were evaluated at 1, 2, and 3 mm levels from the apical foramen. The number of accessory canals, the dentinal thickness, and cross-sectional appearance of the canal at different root levels were also recorded. Expression of deep grooves was observed in 21.42% of the sample. Mean lengths of root and RG were 13.43 mm and 8.5 mm, respectively, while depth of the RG ranged from 0.75 to 1.13 mm. Mean canal volume, surface area and SMI were 10.78 mm3, 58.51 mm2, and 2.84, respectively. Apical delta was present in 4.35% of the sample and accessory canals were observed mostly at the middle and apical thirds. Two-dimensional parameters indicated an oval-shaped cross-sectional appearance of the root canal with a high percentage frequency of canal divisions (87.15%). Canal configuration type V (58.57%) was the most prevalent. C-shaped configuration was observed in 13 premolars (18.57%), whereas dentinal thickness ranged from 1.0 to 1.31 mm. Radicular grooves in mandibular first premolars was associated with the occurrence of several anatomical complexities, including C-shaped canals and divisions of the main root canal.

Resumo O objetivo deste estudo foi avaliar a morfologia de 70 pré-molares inferiores com depressões radiculares (DR) usando a microtomografia. Os dentes foram escaneados e avaliados quanto à morfologia das raízes e canais radiculares, bem como o comprimento, profundidade, frequência e localização das DR. O volume, a área de superfície e o Structure Model Index (SMI) dos canais foram mensurados no comprimento total da raiz. Parâmetros bidimensionais e orifícios do canal foram avaliados a 1, 2 e 3 mm do forame apical. O número de canais acessórios, a espessura dentinária e a aparência transversal do canal em diferentes níveis de raiz também foram registrados. A expressão de sulcos profundos foi observada em 21,42% da amostra. Os comprimentos médios de raiz e DR foram de 13,43 mm e 8,5 mm, respectivamente, enquanto a profundidade das DR variou de 0,75 a 1,13 mm. O volume médio do canal, a área superficial e o SMI foram de 10,78 mm3, 58,51 mm2 e 2,84, respectivamente. O delta apical estava presente em 4,35% da amostra e os canais acessórios foram observados principalmente nos terços médio e apical. Os parâmetros bidimensionais indicaram canais radiculares com secção oval e alta frequência de divisões canal principal (87,15%). A configuração Tipo V do canal radicular foi a mais prevalente (58,57%). A presença de canais em forma de C foi observada em 13 pré-molares (18,57%), enquanto a espessura dentinária variou de 1,0 a 1,31 mm. Os sulcos radiculares nos primeiros pré-molares inferiores foram associados à ocorrência de várias complexidades anatômicas, incluindo canais em forma de C e múltiplas divisões do canal principal.

Analysis of the shelf life of chitosan stored in different types of packaging, using colorimetry and dentin microhardness.

OBJECTIVES: Chitosan has been widely investigated and used. However, the literature does not refer to the shelf life of this solution. This study evaluated, through the colorimetric titration technique and an analysis of dentin micro-hardness, the shelf life of 0.2% chitosan solution. MATERIALS AND METHODS: Thirty human canines were sectioned, and specimens were obtained from the second and third slices, from cemento-enamel junction to the apex. A 0.2% chitosan solution was prepared and distributed in 3 identical glass bottles (v1, v2, and v3) and 3 plastic bottles (p1, p2, and p3). At 0, 7, 15, 30, 45, 60, 90, 120, 150, and 180 days, the specimens were immersed in each solution for 5 minutes (n = 3 each). The chelating effect of the solution was assessed by micro-hardness and colorimetric analysis of the dentin specimens. 17% EDTA and distilled water were used as controls. Data were analyzed statistically by two-way and Tukey-Kramer multiple comparison (α = 0.05). RESULTS: There was no statistically significant difference among the solutions with respect to the study time (p = 0.113) and micro-hardness/time interaction (p = 0.329). Chitosan solutions and EDTA reduced the micro-hardness in a similar manner and differed significantly from the control group (p < 0.001). Chitosan solutions chelated calcium ions throughout the entire experiment. CONCLUSIONS: Regardless of the storage form, chitosan demonstrates a chelating property for a minimum period of 6 months.

Common Operative Procedural Errors and Clinical Factors Associated with Root Canal Treatment.

Operative procedural errors must be well analyzed in order to avoid influence negatively the root canal treatment (RCT) prognosis. The successful RCT prevents tooth loss and avoids pain and apical periodontitis. This review aimed to categorize common operative procedure errors and clinical factors associated with RCT. Based on this, will be approached common errors of procedures within the clinical operative sequence: endodontic treatment planning, pulp and periapical disease diagnosis, anaesthesia, access cavity preparation, isolation with rubber dam, root canal preparation, root canal filling and retreatment, restoration of endodontically treated teeth, postoperative pain, follow up of endodontically treated teeth. The professional must remind that in each phase of RCT an operative error may have adverse implication on prognosis, and these errors characterize risk factors to failure. The knowledge of probable operative procedural errors and its consequences are essentials to avoid future problems to the tooth health.

Common Operative Procedural Errors and Clinical Factors Associated with Root Canal Treatment

Abstract Operative procedural errors must be well analyzed in order to avoid influence negatively the root canal treatment (RCT) prognosis. The successful RCT prevents tooth loss and avoids pain and apical periodontitis. This review aimed to categorize common operative procedure errors and clinical factors associated with RCT. Based on this, will be approached common errors of procedures within the clinical operative sequence: endodontic treatment planning, pulp and periapical disease diagnosis, anaesthesia, access cavity preparation, isolation with rubber dam, root canal preparation, root canal filling and retreatment, restoration of endodontically treated teeth, postoperative pain, follow up of endodontically treated teeth. The professional must remind that in each phase of RCT an operative error may have adverse implication on prognosis, and these errors characterize risk factors to failure. The knowledge of probable operative procedural errors and its consequences are essentials to avoid future problems to the tooth health.

Resumo Erros de procedimentos operatórios devem ser bem analisados e evitados em função de influenciar negativamente o prognóstico do tratamento do canal radicular. Tratamento do canal radicular bem sucedido previne a perda do dente, evita dor pulpar e lesão periapical. Esta revisão objetiva categorizar erros de procedimentos operatórios comuns e os fatores clínicos associados ao tratamento do canal radicular. Neste intuito, serão abordados os erros mais comuns e os fatores clínicos dentro da seguinte sequência operatória: planejamento do tratamento endodôntico, diagnóstico da doença pulpar e periapical, anestesia, preparo do acesso cavitário, isolamento do campo operatório, preparo do canal radicular, obturação e retratamento do canal radicular, restauração do dente tratado endodonticamente, dor pós-tratamento do canal radicular, e acompanhamento do dente tratado endodonticamente. O profissional deve estar consciente de que em cada fase operatória um erro pode ter implicação no prognóstico, e ser fator de risco ao fracasso. O conhecimento dos prováveis erros de procedimentos operatórios e suas consequências é essencial para evitar futuros problemas com a saúde do dente.

Morphological Study and Analysis of Microhardness and Permeability of the Furcation of Maxillary Premolars.

The morphology, microhardness and dentin permeability of the furcation region of maxillary premolars were evaluated. Ten premolars were cut lengthwise and the furcation region was delimited. In one group (n=10) microhardness was measured in the buccal, central and palatal regions, in the outer middle and inner layers of the furcation, and in the buccal and palatal regions adjacent to the furcation. Knoop hardness was tested with 10 g load for 15 s. Data were analyzed statistically by ANOVA and Tukey-Kramer test (a=0.05). In the other group (n=10) confocal microscopy was used to study dentin morphology. Other 10 specimens were instrumented with ProTaper and immersed in 10% copper sulfate for analysis of permeability under light microscopy. About microhardness, there was no significant difference (p>0.05) among the buccal (39.9±3.1), central (39.5±4.4) and palatal (39.7±5.0) regions of the furcation, or between these regions and the adjacent buccal (39.1±5.8) and palatal (39.7±5.8) regions (p>0.05). The inner layer (42.3±3.7) had significantly higher microhardness (p<0.05) than the outer layer (37.1±3.9). There was a tendency of calcification of the dentinal tubules from the outer towards the inner layer. The percentage of stained area was 12.45±2.0%, restricted to the outer layer. The buccal, central and palatal regions of the furcation as well as the buccal and palatal adjacent regions had similar microhardness values. In conclusion, the inner dentin layer is harder than the outer dentin layer. The dentinal tubules are sinuous and intertwine towards the middle layer. Dye penetration is restricted to the outer layer.

Zinc Oxide Nanoparticles Enhance Physicochemical Characteristics of Grossman Sealer.

INTRODUCTION: Metallic antibacterial nanoparticles have been shown to provide distinct antibacterial advantage and antibiofilm efficacy when applied in infected root canals. The purpose of this study was to evaluate the influence of incorporating zinc oxide nanoparticles (ZnO-Np) on the physicochemical properties of Grossman sealer. METHODS: Grossman sealer was prepared according to its original formula. Additionally, 4 experimental sealers were prepared by replacing the zinc oxide component of the powder with ZnO-Np (average size of 20 nm) in different amounts (25%, 50%, 75%, and 100%). Characterization of the setting time, flow, solubility, dimensional changes, and radiopacity were performed according to American National Standards Institute (ANSI)/American Dental Association (ADA) Specification 57. Scanning electron microscopic and energy-dispersive X-ray spectroscopic analyses were conducted to assess the ultrastructural and chemical characteristics of experimental sealers subjected to the solubility test. Statistical analyses were performed with analysis of variance and post hoc Tukey-Kramer tests with a significance level of 5%. RESULTS: A statistically significant difference in the setting time was observed among groups (P < .05), but only 25% ZnO-Np sealer complied with ANSI/ADA requirements. There was a significant difference in the flow characteristics between the control and 25% and 75% ZnO-Np experimental sealers (P < .05), but all sealers conformed to ANSI/ADA standardization; 25% ZnO-Np sealer showed significantly less solubility (1.81% ± 0.31%) and dimensional change (-0.34% ± 0.12%) than other sealers (P < .05). All sealers showed ultrastructural changes with increasing solubility. CONCLUSIONS: ZnO-Np decreased the setting time and dimensional changes characteristic of Grossman sealer; 25% ZnO-Np improved the physicochemical properties of Grossman sealer in accordance with ANSI/ADA requirements.

Morphological Study and Analysis of Microhardness and Permeability of the Furcation of Maxillary Premolars

Abstract The morphology, microhardness and dentin permeability of the furcation region of maxillary premolars were evaluated. Ten premolars were cut lengthwise and the furcation region was delimited. In one group (n=10) microhardness was measured in the buccal, central and palatal regions, in the outer middle and inner layers of the furcation, and in the buccal and palatal regions adjacent to the furcation. Knoop hardness was tested with 10 g load for 15 s. Data were analyzed statistically by ANOVA and Tukey-Kramer test (a=0.05). In the other group (n=10) confocal microscopy was used to study dentin morphology. Other 10 specimens were instrumented with ProTaper and immersed in 10% copper sulfate for analysis of permeability under light microscopy. About microhardness, there was no significant difference (p>0.05) among the buccal (39.9±3.1), central (39.5±4.4) and palatal (39.7±5.0) regions of the furcation, or between these regions and the adjacent buccal (39.1±5.8) and palatal (39.7±5.8) regions (p>0.05). The inner layer (42.3±3.7) had significantly higher microhardness (p<0.05) than the outer layer (37.1±3.9). There was a tendency of calcification of the dentinal tubules from the outer towards the inner layer. The percentage of stained area was 12.45±2.0%, restricted to the outer layer. The buccal, central and palatal regions of the furcation as well as the buccal and palatal adjacent regions had similar microhardness values. In conclusion, the inner dentin layer is harder than the outer dentin layer. The dentinal tubules are sinuous and intertwine towards the middle layer. Dye penetration is restricted to the outer layer.

Resumo Estudou-se a morfologia, microdureza e permeabilidade dentinária da furca de pré-molares superiores. Dez pré-molares tiveram a porção oclusal da coroa e os terços radiculares médio e apical removidos. Cortou-se longitudinalmente o remanescente e delimitou-se a furca. As hemi-secções foram distribuídas em dois grupos. Num (n=10), mediu-se a microdureza nas regiões vestibular, central e palatina, nas camadas externa, média e interna e nas porções vestibular e palatina adjacentes à furca. Utilizou-se dureza Knoop, carga de 10 g por 15 s. Os dados foram analisados pelo teste ANOVA e Tukey-Kramer (a=0.05). No outro grupo (n=10) utilizou-se microscopia confocal para estudo da morfologia da dentina. Outros 10 espécimes foram instrumentados com Protaper e NaOCl a 1% e imersos em sulfato de cobre a 10% para análise da permeabilidade. Após preparo histológico os espécimes foram analisados em fotomicroscópio. Não houve diferença significante (p>0,05) entre a microdureza das regiões vestibular (39,9±3,1), central (39,5±4,4) e palatina (39,7±5,0), nem entre essas regiões e as adjacentes vestibular (39,1±5,8) e palatina (39,7±5,8) (p>0,05). A camada interna (42,3±3,7) é mais dura que a externa (37,1±3,9) (p<0,05). Há uma tendência dos canalículos calcificarem no sentido da camada externa para a interna. A porcentagem de área corada foi de 12,45±2.0 e restrita à camada externa. As regiões vestibular, central e palatina da furca, bem como as adjacentes vestibular e palatina apresentaram microdureza semelhante entre si. A camada interna apresentou-se mais dura que a externa. Os canalículos dentinários eram sinuosos e se entrelaçaram em direção à camada média. A penetração de corantes se restringiu à camada externa.

Micro-computed tomographic evaluation of removal and extrusion of root filling material during canal retreatment / Avaliação por meio de microtomografia computadorizada da remoção e extrusão de material obturador durante retratamento endodôntico

This study aimed to assess the efficiency of manual and rotary techniques for removing root filling material in endodontic treated canals and to evaluate the extrusion of debris via apical foramen. After access preparation, thirty human lower central incisors were instrumented, filled and divided into two groups (n=15): MNmanual retreatment technique; RT- rotary retreatment technique. The teeth were submitted to micro-computed tomographic scanning before and after the retreatment procedure, for quantifying the remaining filling material by relating the initial and final conditions. The analysis was conducted separately in all root thirds. The volume of material extruded through the apical foramen was also quantified. The data were statistically analyzed using t-test and two-way analysis of variance (ANOVA) at 5% of significance. No significant differences were detected between remaining filling material for the techniques evaluated (p=0.74), even considering the apical third only (p>0.75). Significant differences were found for the remaining filling material verified between the cervical third and middle/apical thirds, with lower values being observed at the cervical third for both groups (p<0.05). Apical extrusion of filling material was verified in seven specimens (2 from MN group and 5 from RT group). Both techniques showed similar performance for removing filling material from the root canal, considering the whole tooth or the root thirds independently. The apical extrusion of filling material observed was not sufficient to indicate which technique has increased tendency to induce more events during retreatments.

Este estudo objetivou avaliar a eficiência das técnicas manual e rotatória na remoção de material obturador de dentes tratados endodonticamente, além de verificar a extrusão de resíduos via forame apical. Após acesso endodôntico, trinta incisivos centrais inferiores humanos foram instrumentados, obturados e divididos em dois grupos (n=15): MN- técnica de retratamento manual; RT- técnica de retratamento rotatória. Os dentes foram submetidos à escaneamento micro-tomográfico previamente e após os procedimentos de retratamento para quantificação do remanescente de material obturador relacionando as condições inicial e final. Esta análise foi conduzida separadamente em todos os terços radiculares. O volume de material extruído via forame apical também foi quantificado. Os dados foram analisados estatisticamente por meio dos Testes T e de Análise de Variância em dois níveis com significância em 5%. Diferenças significantes não foram detectadas entre a quantidade de material remanescente para as duas técnicas avaliadas (p=0,74), mesmo considerando o terço apical separadamente (p>0.75). Diferenças significantes foram encontradas na quantidade de material remanescente verificado entre os terços cervical e médio/apical, com menores valores detectados no terço cervical para ambos os grupos (p<0.05). Extrusão apical de material obturador foi identificada em sete espécimes (2 do grupo MN e 5 do grupo RT). As duas técnicas avaliadas apresentaram desempenho similar na remoção do material obturador do canal radicular, considerando o dente como um todo ou os terços radiculares separadamente. A extrusão apical de material obturador verificada não foi suficiente para indicar qual técnica possui maior tendência de promover eventos durante o retratamento.

Volume of sealer in the apical region of teeth filled by different techniques: a micro-CT analysis.

The volume of sealer in the apical 1 mm of teeth filled using different techniques was evaluated by micro-commuted tomography (micro-CT). Sixty-four maxillary central incisors were prepared using NiTi rotary instruments. Teeth were randomly distributed into four groups according to root canal sealers (AH Plus, Endofill, Sealapex, and Sealer 26) and subdivided into two subgroups according to the filling techniques (active and passive lateral condensation; n = 8 each). Subsequently, teeth were examined using the 1174 SkyScan micro-CT device. Images were reconstructed using the NRecon software, and the sealer volume (mm3) in the apical region was analyzed using the two-way ANOVA and post-hoc Student-Newman-Keuls test (α = 0.05). The lowest volume of sealer was observed in teeth filled with Sealapex (0.100 ± 0.009) and Endofill (0.103 ± 0.010). The highest volume was observed in teeth filled with AH Plus (0.112 ± 0.008) and Sealer 26 (0.109 ± 0.018) (p > 0.05). Regarding the filling technique, a lower sealer volume was observed using the active lateral condensation technique compared with that using the passive lateral condensation technique (0.100 ± 0.010 vs. 0.111 ± 0.012) (p < 0.05). Therefore, the lowest volume of sealer was observed in teeth filled with Sealapex and Endofill using the active lateral condensation technique.

Study of Anatomical Relationship between Posterior Teeth and Maxillary Sinus Floor in a Subpopulation of the Brazilian Central Region Using Cone-Beam Computed Tomography - Part 2.

This study evaluated the anatomical relationship between posterior teeth root apices and maxillary sinus floor (MSF) on 202 cone beam computed tomography (CBCT) exams. The distance between the root apices and the MSF, as well as the MSF thickness of the cortical bone closest to root apices and furcation regions were measured. The vertical and horizontal relationships of the MSF with the molar roots were classified into categories adapted from the criteria proposed by Kwak et al. (14). The shortest distances between MSF and the root apices were observed in the mesiobuccal root of the second molar (0.36±1.17 mm) and the palatal root of the first molar (0.45±1.10 mm) and the widest in buccal roots of the first premolars (5.47±4.43 mm). Significant differences were observed between the distance of MSF to the root apices of single-rooted first and second premolars. The cortical thickness ranged from 0.65±0.41 mm over the mesiobuccal root of the second molar to 1.28±0.42 mm over the buccal root of the first premolar. The most observed vertical and horizontal relationships were type II and 2H, respectively. The maxillary molar roots showed greater proximity to the MSF. The thickness of the MSF cortical bone closest to the apices and furcation regions was found to be similar only for premolars.

Study of Anatomical Relationship between Posterior Teeth and Maxillary Sinus Floor in a Subpopulation of the Brazilian Central Region Using Cone-Beam Computed Tomography - Part 2

Abstract This study evaluated the anatomical relationship between posterior teeth root apices and maxillary sinus floor (MSF) on 202 cone beam computed tomography (CBCT) exams. The distance between the root apices and the MSF, as well as the MSF thickness of the cortical bone closest to root apices and furcation regions were measured. The vertical and horizontal relationships of the MSF with the molar roots were classified into categories adapted from the criteria proposed by Kwak et al. (14). The shortest distances between MSF and the root apices were observed in the mesiobuccal root of the second molar (0.36±1.17 mm) and the palatal root of the first molar (0.45±1.10 mm) and the widest in buccal roots of the first premolars (5.47±4.43 mm). Significant differences were observed between the distance of MSF to the root apices of single-rooted first and second premolars. The cortical thickness ranged from 0.65±0.41 mm over the mesiobuccal root of the second molar to 1.28±0.42 mm over the buccal root of the first premolar. The most observed vertical and horizontal relationships were type II and 2H, respectively. The maxillary molar roots showed greater proximity to the MSF. The thickness of the MSF cortical bone closest to the apices and furcation regions was found to be similar only for premolars.

Resumo Avaliou-se a relação anatômica entre dentes posteriores e o soalho do seio maxilar (SSM) por meio da tomografia computadorizada de feixe cônico (TCFC) em 202 exames. A distância entre os ápices radiculares e o SSM, bem como a espessura do osso cortical do SSM próximo dos ápices radiculares e áreas de bifurcação foram medidas. As relações verticais e horizontais do SSM com as raízes dos molares foram classificados em categorias adaptadas a partir dos critérios propostos pelo Kwak et al. (14). A menor distância entre o SSM e os ápices dentários foi observada na raiz mesiovestibular do segundo molar (0,36±1,17 mm) e na raiz palatina do primeiro molar (0,45±1,10 mm), e a maior na raiz vestibular do primeiro pré-molar (5,47±4.43 mm). Diferenças significantes foram observadas entre a distância do SSM e os ápices dentários de primeiros e segundos pré-molares unirradiculares. A espessura da cortical óssea variou de 0,65±0,41 mm na região da raiz mesiovestibular do segundo molar a 1,28±0,42 na raiz vestibular do primeiro pré-molar. As relações vertical e horizontal mais prevalentes foram do tipo II e 2H, respectivamente. As raízes dos molares superiores apresentaram maior proximidade com o SSM. A espessura da cortical óssea do SSM nas regiões mais próximas dos ápices e área de furca foi similar apenas para os pré-molares.