Comparative analysis of three rotary instruments used for coronal pre-enlargement in radicular dentin thickness and root canal area of mandibular molars

Purpose: The purpose of this study was to evaluate the increase of the cervical area and dentin thickness in mesial and distal walls of the mesial canals from mandibular molars after the use of LA Axxess (LA), CP Drill (CP) and Gates-Glidden (GG) rotary instruments. Material and Methods: Sixty root canals from thirty mandibular first molar were sectioned 3 mm below the cement-enamel junction, divided in 3 groups (n = 20 root canals, each) according to rotary instrument used, and the cervical images were captured before and after pre-enlargement instrumentation. The increase of the instrumented cervical area (mm2) and the dentin removal thickness (mm), at mesial and distal walls were calculated using Image tools software, by comparison of images. Data were analyzed by ANOVA and Tukey tests (p=0.05). Results: All rotary instruments promoted thickness reduction in dentin walls. In mesial wall, all rotary instruments promoted similar thickness reduction of dentinal wall and did not differ from each other (p>0.05). In distal wall, LA Axxess instrument promoted higher dentin thickness reduction than other groups (p<0.05). The three rotary instruments promoted different increase at the instrumented cervical area (p<0.05), LA promoted the highest increase area and GG and CP presented similar results. Conclusion: LA 20/0.06 promoted the highest thickness reduction in distal wall and increase of cervical area of root canal. On the other hand, CP was the safest instrument, with lower dentin removal of distal wall and similar increased area to GG

Repair of Iatrogenic Furcal Perforation with Mineral Trioxide Aggregate: A Seven-Year Follow-up

Teeth with furcal perforation present difficult resolution and dubious prognosis. Several materials have been proposed and calcium silicate-based cements such as mineral trioxide aggregate (MTA) are the most recommended. However, its long-term clinical behavior still remains poorly understood. The present study reports a clinical case of furcal perforation repair using Angelus MTA, with a 7-year follow-up. Patient sought treatment 2 months after iatrogenic accident. First lower right molar presented clinical signs such as fistula and bone loss between mesial and distal roots. Firstly, all root canals were treated and then furcal perforation was sealed with MTA Angelus and the dental crown was restored with composite resin. Radiographic evaluation was immediately performed to analyze the furcal perforation filling. After 7 years, a new clinical and imaging evaluation using periapical radiography and cone-beam computed tomography (CBCT) showed absence of clinical signs and symptoms, and alveolar bone reconstitution with periodontal space reduction. Angelus MTA presented good clinical behavior in the iatrogenic furcal perforation resolution based on long-term clinical evidence.Keywords: Endodontics; Furcation Perforation; Mineral Trioxide Aggregate; Root Canal Treatment; Root Perforation; Tooth Perforation

Bond strength and internal adaptation of customized glass fiber posts using different bulk-fill flow resins

This study aimed to evaluate the bond strength and internal adaptation of customized glass fiber posts using Bulk Fill flowable composite resins (BF) and conventional composite resin. Fifty bovine teeth were randomly divided (n=10) according to the fol

Efeitos dos ascorbato de sódio e alfatocoferol na resistência à fratura, resistência de união e na interface adesiva na dentina de dentes tratados endodonticamente submetidos a clareamento dental com peróxido de hidrogênio

This study evaluated the effects of sodium ascorbate and alphatocopherol on fracture resistance, mensuration of the hybrid layer formation and bond strength of an adhesive system used in endodontically treated teeth. The first study used fifty endodontically treated bovine incisors, divided into five groups (n = 10): G1: control; G2: restoration with composite resin; G3: bleaching with 38% hydrogen peroxide and immediate restoration; G4: bleaching, application of 10% sodium ascorbate and restoration; G5: bleaching, alphatocopherol application and restoration. The specimens were subjected to fracture resistance mechanical testing. The obtained data were analyzed by ANOVA and Tukey test,at significance level of 5%. G1 showed higher fracture resistance than the other groups. No statistical difference were found among other groups (p> 0.05).The second study used forty endodontically treated bovine incisors, divided into four groups (n = 10): G1: restoration; G2: bleaching and immediate restoration; G3: bleaching, use of 10% sodium ascorbate and immediate restoration; G4: bleaching, use of 10% alphatocorol and immediate restoration. The bleaching protocol and antioxidant application were similar to experiment 1. The coronal portion was sectioned at buccolingual direction and analyzed by confocal laser microscope at magnification 1024X. The data were subjected to Kruskal-Wallis and Dunn test (p = 0.05). The intradentin extension of the hybrid layer formation was significantly greater in G1 and G3 in relation to G2 and G4 (p 0.05). The third study used 40 specimens, divided into four groups (n = 10), similar to protocols described in experiment 2. The buccal surface of each specimen was ground and included in acrylic resin in the PVC cylinder. Composite resin cylinders were made and bonded to the underlying dentin after adhesive system application...Os objetivos deste estudo foram avaliar os efeitos da utilização do ascorbato de sódio e alfatocoferol na dentina de dentes tratados endodonticamente, através da avaliação da resistência das coroas dentais à fratura, mensuração da formação intradentinária da camada hibrida e sua repercussão sobre a resistência de união de um sistema adesivo. No primeiro estudo, foram utilizados cinquenta incisivos bovinos endodonticamente tratados, distribuídos em cinco grupos (n = 10). Sendo, G1 controle, G2: somente restaurados com resina composta, G3: clareado com peróxido de hidrogênio a 38% e restaurado imediatamente, G4: clareado e tratado com ascorbato de sódio a 10%, G5: clareado e tratado alfatocoferol. Os espécimes foram submetidos ao teste mecânico de resistência à fratura, sendo que G1 apresentou maior resistência à fratura que os demais grupos. Não foi observada diferença estatística entre os demais grupos (p > 0,05). No segundo estudo, foram utilizados quarenta incisivos bovinos tratados endodonticamente, divididos em quatro grupos (n = 10): G1 restaurado (controle), G2 clareado e restaurado imediatamente, G3 clareado, tratado com ascorbato de sódio a 10% e restaurado imedimediata, G4 clareado, tratado com alfatocoferol 10% e restaurado imediata. O protocolo de clareamento e a utilização dos agentes antioxidantes foram iguais ao do experimento 1. Somente a porção coronária seccionada, no sentido vestíbulo-lingual de cada espécime foi utilizada para análise em microscópio laser confocal com aumento de 1024X. Os dados obtidos foram submetidos aos testes de Kruskal-Wallis e Dunn (p =0,05). A extensão intradentinária da formação da camada hibrida foi significantemente maior em G1 e G3, em relação a G2 e G4 (p 0,05). No terceiro estudo, a superfície vestibular de cada espécime foi desgastada e incluída em resina..

Effect of the time-point of acid etching on the persistence of sealer residues after using different dental cleaning protocols

Abstract: Endodontic sealer residues remaining within the pulp chamber dentin after root canal obturation and cleaning with various solvents may compromise the appearance and the durability of dental restorations. Acid etching is routinely performed prior to application of dentine adhesive systems, but is effect on residual sealer material and the optimal time-point for performing etching, are unknown. Here, we evaluated the effect of acid etching on the dentin surface when performed either immediately or 7 days after removal of the endodontic sealer with two solvents, i.e., 95% ethanol or xylol. Forty crowns fragments from bovine incisors were impregnated with sealer and divided into 4 groups (n = 10 each), according to the dentin cleaning protocol and to the acid etching time-point: G1, 95.0% ethanol and immediate acid etching; G2, xylol and immediate acid etching; G3, 95.0% ethanol and acid etching after 7 days; and G4, xylol and acid etching after 7 days. Scanning electron microscopy (SEM) images (2000 ×) were obtained from each specimen and the number of open dentinal tubules counted and compared. Another 40 fragments were similarly prepared, and SEM images were obtained (500 ×) to score and compare the persistence of sealer residues on the dentin. G4 showed the most open dentinal tubules and the least epoxy resin-based sealer residues on the dentin surface (p < 0.05). The least epoxy resin-based sealer residues was obtained when acid etching, using 37% phosphoric acid, was performed after 7 days after cleaning the dentin with xylol

Effects of alpha-tocopherol on fracture resistance after endodontic treatment, bleaching and restoration

Abstract This study evaluated the effects of 10% alphatocopherol on the fracture resistance of endodontically treated teeth subjected to tooth bleaching with hydrogen peroxide and immediately restored with composite resin. Fifty bovine incisors were selected, including 10 sound teeth that constituted the control group (G1 (C)). The remaining 40 teeth, which were endodontically treated, were divided into four groups (n = 10): G2 (CR), consisting of teeth immediately restored with composite resin; G3 (HP + CR), consisting of teeth subjected to tooth bleaching with 38% hydrogen peroxide and immediately restored with composite resin; G4 (HP + SA + CR), which received treatment similar to that used for G3, but with 10% sodium ascorbate gel applied after the bleaching protocol; and G5 (HP + AT + CR), which was similar to G4 but included 10% alphatocopherol gel as an antioxidant. After 24 h, composite restorations were performed, and teeth were subjected to a fracture resistance test at a speed of 0.5 mm/min in an electromechanical testing machine. The axial force was applied with an angle of incidence of 135° relative to the long axis of the root. Data were subjected to ANOVA and Tukey tests (p = 0.05). G1 exhibited the highest fracture resistance (p < 0.05). No significant differences among the other experimental groups were observed. The 10% sodium ascorbate and 10% alphatocopherol gels did not improve the fracture resistance of endodontically treated teeth subjected to bleaching with 38% hydrogen peroxide