Avaliação in vitro de diferentes agentes de descontaminação de cones de guta-percha

This study evaluated the effectiveness of three disinfectants used in Dentistry for decontamination of gutta-percha cones. Sixty gutta-percha cones were contaminated with standardized pure cultures of five species of microorganisms (Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, Candida albicans ATCC CBS-ICB/USP 562, Bacillus subtilis spores ATCC 6633 and Streptococcus mutans ATCC 25175). The cones were treated with 10% polyvinylpyrrolidone-iodine aqueous solution (PVP-I; Groups 1 and 2), 5.25% aqueous sodium hypochlorite (Groups 3 and 4) and paraformaldehyde tablets (Group 5). All chemical agents were efficient for the cold sterilization of gutta-percha cones in short time periods.A eficiência de três desinfetantes usados em Odontologia foi estudada na descontaminação de 60 cones de guta-percha contaminados com culturas puras e padronizadas de cinco cepas de microrganismos (Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, Candida albicans ATCC CBS-ICB/USP 562, Bacillus subtilis em esporos ATCC 6633 e Streptococcus mutans ATCC 25175). Os cones foram tratados com solução aquosa de polivinilpirrolidona-iodo 10% (PVP-I; Grupos 1 e 2), solução aquosa de hipoclorito de sódio 5,25% (Grupos 3 e 4) e pastilhas de formaldeído (Grupo 5). Nossos resultados indicam que todos os agentes químicos foram eficientes para a esterilização a frio dos cones de guta-percha em curtos espaços de tempo

Effect of different solutions in reversing the damage caused by radiotherapy in dentin structure

Previous studies have shown that radiotherapy of the head and neck region can cause direct changes in dental structure. This study evaluated the effect of different solutions on the dentin chemical composition and collagen structure of irradiated dentin. Sixty maxillary canines were distributed in 2 groups (n=30): non-irradiated and irradiated (radiotherapy: X-rays of 6 MV in 30 cycles of 2 Gy to 60 Gy). The teeth were sectioned, sanded, and polished to obtain 3x3x2 mm fragments, which were redistributed in 3 subgroups (n=10) according to the treatment employed: chlorhexidine 2% (CL), chitosan 0.2% (QT), and 0.5 M carbodiimide (EDC). The samples were analyzed in FTIR at time zero (T0-control) and after 1 (T1), 3 (T3), and 5 (T5) minutes of immersion in the tested solutions. The data for the areas of the carbonate (C), amide I (AI) bands, and the ratio between the areas of the amide III/proline and hydroxyproline (AIII/PH) bands were analyzed using ANOVA and Tukey test (?=5%). QT showed lower C values at T1, T3, and T5 (P0.05). Radiotherapy changes the secondary structure of collagen, and EDC was able to restore collagen integrity after 1 minute of immersion, without changing dentin inorganic composition

Adhesion of an endodontic sealer to dentin and gutta-percha: shear and push-out bond strength measurements and SEM analysis

The use of an adequate method for evaluation of the adhesion of root canal filling materials provides more reliable results to allow comparison of the materials and substantiate their clinical choice. The aims of this study were to compare the shear bond strength (SBS) test and push-out test for evaluation of the adhesion of an epoxy-based endodontic sealer (AH Plus) to dentin and gutta-percha, and to assess the failure modes on the debonded surfaces by means of scanning electron microscopy (SEM). Three groups were established (n=7): in group 1, root cylinders obtained from human canines were embedded in acrylic resin and had their canals prepared and filled with sealer; in group 2, longitudinal sections of dentin cylinders were embedded in resin with the canal surface smoothed and turned upwards; in group 3, gutta-percha cylinders were embedded in resin. Polyethylene tubes filled with sealer were positioned on the polished surface of the specimens (groups 2 and 3). The push-out test (group 1) and the SBS test (groups 2 and 3) were performed in an Instron universal testing machine running at crosshead speed of 1 mm/min. Means (±SD) in MPa were: G1 (8.8±1.13), G2 (5.9±1.05) and G3 (3.8±0.55). Statistical analysis by ANOVA and Student's t-test (a=0.05) revealed statistically significant differences (p<0.01) among the groups. SEM analysis showed a predominance of adhesive and mixed failures of AH Plus sealer. The tested surface affected significantly the results with the sealer reaching higher bond strength to dentin than to gutta-percha with the SBS test. The comparison of the employed methodologies showed that the SBS test produced significantly lower bond strength values than the push-out test, was skilful in determining the adhesion of AH Plus sealer to dentin and gutta-percha, and required specimens that could be easily prepared for SEM, presenting as a viable alternative for further experiments

Endocoroa em pré-molar utilizando cerâmica reforçada por dissilicato de lítio: um relato de caso

This study reported a clinical case about restoration of an endodontically treated tooth using an endocrown in lithium disilicate-reinforced ceramic fabricated by CAD/CAM system. Case of a female patient, 48 years old who presented coronal fracture of an endodontically treated tooth. Restoration with endocrown in lithium disilicate-reinforced ceramic fabricated by CAD/CAM system was indicated. The crowns were evaluated using a California Dental Association (CDA) quality assessment system at baseline and at follow-up examination. Endocrown in lithium disilicate-reinforced ceramic fabricated by CAD/CAM system was a reliable restorative alternative for an endodontically treated premolar. The minimally invasive prepare for endocrown preserves maximum tooth structure as a gold standard for tooth restorations. In addition, such restorative alternative is advantageous in comparison to conventional full post-and-core supported crown since it presents appropriate mechanical performance and longevity as a lower cost and faster clinical procedure.Este caso clínico descreve a restauração de um dente tratado endodonticamente com uma endocoroa em cerâmica de dissilicato de lítio fabricada pelo sistema CAD/CAM. O caso é de uma paciente do sexo feminino, 48 anos, que apresentava fratura coronária de um dente tratado endodonticamente. Uma restauração com endocoroa em dissilicato de lítio fabricada pelo sistema CAD/CAM foi indicada. As coroas foram avaliadas usando um sistema de avaliação de qualidade da Associação Dental da Califórnia e exame de acompanhamento. Uma endocoroa cerâmica em dissilicato fabricada por CAD/CAM foi uma alternativa de tratamento restaurador confiável para um pré-molar tratado endodonticamente. O preparo minimamente invasivo para endocoroa que preserva o máximo de estrutura dentária é considerado padrão ouro para restaurações dentárias. Ainda, tal alternativa restauradora é mais conservadora em comparação à coroa total com retentor intrarradicular e apresenta apropriado desempenho mecânico e longevidade com um menor custo e rapidez no preparo

Micro-computed tomographic assessment of the variability and morphological features of root canal system and their ramifications

Objectives: This study assessed the incidence and variability features of root canals system (RCS) and their ramifications according to Pucci &amp; Reig (PR) (1944) and the American Association of Endodontists (AAE) (2017) by micro-computed tomography (μCT). Methodology: 500 representative extracted human teeth of each tooth group (n=50) (maxillary/mandibular central and lateral incisors, canines, first and second premolars and molars) were scanned by μCT with a resolution of 26.70 μm. The reconstructed cross-sections images and the visualization of the continuous slices in the transversal axis were performed using DataViewer software. RCS were classified according to Pucci &amp; Reig (main canal, collateral canal, lateral canal, secondary canal, accessory canal, intercanal, recurrent canal) and AAE (main canal, accessory canal, lateral canal). The apical deltas were assessed for both classifications. The prevalence of apical deltas was evaluated using the Chi-squared test (p&lt;0.05). Results: According to PR, a higher incidence of lateral canals was observed in maxillary canines (10%), central incisors (8%) and first premolars (6%). Using AAE, the highest incidence of lateral canals was observed in the mandibular first premolars (85%), first and second molars (84%), lateral incisors (67%), canines (59%), and in maxillary first premolars (52%). Regarding accessory canals, the PR showed a frequency in 2% of the maxillary lateral incisors and maxillary and mandibular first premolars and 3% of mandibular first and second molars. On the other hand, the AAE showed the highest incidence of accessory canals in 86% of the maxillary first premolars, 71% in mandibular lateral incisors, 69% in mandibular first premolars, 65% in mandibular canines, and 56% in maxillary canines. The PR showed the lowest incidence of apical deltas for all dental groups when compared with AAE (p=0.004). Interestingly, distal canals in maxillary molars showed a significant discrepancy between classifications (p=0.027).&nbsp;Conclusions: μCT enabled accurately describing the RC system and related ramifications, adding to the PR and AAE classifications, with some discrepancies reported for maxillary molars. Clinical Relevance This μCT study enabled a thorough description of the variability among root canals and their ramifications, including clinically relevant details on the presence and location of lateral canals and accessories in all human tooth groups, beyond the currently existing classification systems

Resistência à fratura de pinos de fibra de vidro e metálicos fundidos com diferentes configurações

PURPOSE: To evaluate the in vitro fracture resistance of roots with glass-fiber and metal dowels with different designs. METHODS: Fifty-endodontically treated maxillary central incisors were embedded in acrylic resin. Ten of them received only the coronary preparation, and the remaining forty were embedded (except for 4mm of the cervical area) after removing the clinical crowns. Specimens were divided into five groups (n=10): control (teeth with only coronary preparation), cylindrical cast dowel, conical cast dowel, cylindrical glass-fiber dowel and conical glass-fiber dowel. Specimens were subjected to an increasing compressive load (N) until fracture. RESULTS: ANOVA indicated significant difference (P<.05) among the groups, and the Tukey-Kramer´s test identified these differences. The control group (867±243 N) presented the highest values and was statistically similar to cylindrical glass-fiber dowel group (711±180 N). There is no significant difference among the metal dowel cylindrical (435±245 N) or conical (585±164 N) group and conical glass-fiber dowel (453±112 N). Cylindrical glass-fiber dowel (711±180 N) and conical cast dowel and core (585±164 N) groups had intermediate values and did not differ from each other. CONCLUSIONS: Cylindrical glass fiber dowels represent a viable alternative to the cast-metal dowel cylindrical or conical. Cylindrical glass fiber dowels also increase endodontically treated incisors' resistance to fracture

Shaping Ability of Single-File Systems with Different Movements: A Micro-Computed Tomographic Study

Introduction: This study aimed to perform a rigorous sample standardization and also evaluate the preparation of mesiobuccal (MB) root canals of maxillary molars with severe curvatures using two single-file engine-driven systems (WaveOne with reciprocating motion and OneShape with rotary movement), using micro-computed tomography (micro-CT). Methods and Materials: Ten MB roots with single canals were included, uniformly distributed into two groups (n=5). The samples were prepared with a WaveOne or OneShape files. The shaping ability and amount of canal transportation were assessed by a comparison of the pre- and post-instrumentation micro-CT scans. The Kolmogorov-Smirnov and t-tests were used for statistical analysis. The level of significance was set at 0.05. Results: Instrumentation of canals increased their surface area and volume. Canal transportation occurred in coronal, middle and apical thirds and no statistical difference was observed between the two systems (P&gt;0.05). In apical third, significant differences were found between groups in canal roundness (in 3 mm level) and perimeter (in 3 and 4 mm levels) (P&lt;0.05). Conclusion: The WaveOne and One Shape single-file systems were able to shape curved root canals, producing minor changes in the canal curvature.Keywords: Micro-Computed Tomography; OneShape; Reciprocating Motion; Rotary System; WaveOn

Influence of bioceramic intracanal medication on the bond strength of bioceramic root canal sealer

Abstract To investigate the influence of the remaining volume of a new intracanal medication based on bioceramic compounds on the bond strength (BS) and formation of an adhesive interface between calcium silicate-based and epoxy resin-based root canal sealers. For this purpose, the specimens were distributed according to the intracanal medication (n = 26): Bio-C Temp (BCT) and Ultracal XS (UXS). The roots were scanned in microCT, and after 7 days, the medication was removed. Then a new scan was performed to evaluate the volume of medication remaining. Subsequently, 40 specimens were redistributed into 2 subgroups (n = 10) and filled according to the sealer used: AH Plus (AHP) and Bio-C Sealer (BCS), to assess the bond strength by using the push-out test, and the adhesive interface by confocal laser fluorescence microscopy (CLSM) and scanning electron microscopy (SEM). The t test showed a smaller remainder of BCT (1.77 ± 0.86) compared with UXS (10.47 ± 5.78), irrespective of the root third evaluated. The BS showed that teeth with BCT + BCS had higher bond strength values (3.70 ± 1.22) when compared to the other groups: BCT + AHP (2.15 ± 1.07), UXS + BCS (3.18 ± 1.09) and UXS + AHP (2.11 ± 1.02) (p<0.001). The cervical third had higher BS when compared with the middle and apical thirds (p < 0.001), and higher number of adhesive failures. The adhesive interface in SEM and CLSM images showed better adaptation for the association between BCT + BCS. Intracanal medication and silicate-based endodontic sealer appeared to interact chemically by forming a biomineralizing layer, allowing for an increase in the bond strength and forming an adhesive interface between the materials, with no or less gap formation

Analysis of the internal anatomy of mandibular molars using different cone-beam computed tomography protocols

The aim of this study was to analyze the root canal anatomy variations of permanent mandibular molars using three different cone-beam computed tomography (CBCT) protocols. Material and methods: Thirty-five freshly extracted first and second mandibular molars were collected and subjected to three CBCT protocols: i-CAT Classic (ICC); i-CAT Next Generation (ICN), and PreXion 3D (PXD). Images were evaluated by two previously calibrated and experienced endodontists. The morphological root canal configurations were classified according to Vertucci. Data were analyzed for frequency, and the binomial and Kappa tests were then performed (α = 0.05). Results: ICC and ICN were able to diagnose a higher percentage of anatomical variations in the mesial roots. In this same root, Vertucci’s type V was the most prevalent, and in distal was the type I. In comparisons of CBCT techniques for agreement, significant differences in the mesial root canals were found in the following: ICC versus (vs) ICN; ICC vs PXD; and ICN vs PXD (p 0.05). The level of agreement in mesial roots was poor or absent, while in distal was moderate. Conclusion: Anatomical variations were found in both root canals, with higher variability in the mesial, highlighting ICC and ICN protocols, and the prevalence of Vertucci’s type V, while in the distal prevailed the type I

Periapical surgery to remove granulomatous lesion: case report

Granuloma periapical é um termo histológico que refere-se à formação de uma massa de tecido granulomatoso ao redor do ápice de um dente, decorrente da inflamação e necrose do tecido pulpar. É constituído por um infiltrado de células inflamatórias como macrófagos, plasmócitos e linfócitos, além de fibroblastos, fibras colágenas e capilares. A cirurgia do periápice é uma alternativa para preservação do dente na cavidade bucal nos casos em que a inflamação periapical é persistente mesmo após tratamento dos canais radiculares. O objetivo desse trabalho é relatar um caso clínico no qual a técnica cirúrgica do periápice foi utilizada para remoção de lesões granulomatosas de uma paciente, do sexo feminino, com histórico de abscesso periapical recidivante sem sintomatologia dolorosa na região dos dentes anteriores superiores 11, 12 e 13. O exame histopatológico demonstrou a presença de um tecido granulomatoso com intenso infiltrado inflamatório misto, permeado com linfócitos e elevado número de plasmócitos, confirmando o diagnóstico de granuloma periapical. O tratamento foi considerado exitoso, visto que a paciente se manteve asintomática e houve incorporação do enxerto ósseo bovino inorgânico e início da neoformação óssea na região periapical.Periapical granuloma is a histological term that refers to the formation of a mass of granulomatous tissue around the apex of a tooth resulting from inflammation and necrosis of the pulp tissue. It consists of an infiltrate of inflammatory cells such as macrophages, plasmocytes and lymphocytes, as well as fibroblasts, collagen fibers and capillaries. Periapical surgery is an alternative for preserving the tooth in the oral cavity in cases where periapical inflammation is persistent even after treatment of root canals. The objective of this study was to report a clinical case in which the surgical technique was used to remove granulomatous lesions from a patient, female, with a history of recurrent periapical abscess without painful symptomatology in the region of the anterior 11,12 and 13 teeth. The histopathological exam demonstrated the presence of a granulomatous tissue with intense inflammatory infiltrate mixed, permeated with lymphocytes and high number of plasmocytes, confirming the diagnosis of periapical granuloma. The treatment was considered successful since the patient remained asymptomatic and there was incorporation of the inorganic bovine bone graft and initiation of bone neoformation in the periapical region