ABSTRACT
This study evaluated the influence of relining fiber posts on the bond strength (BS) of resin cements in the root canal. Forty bovine teeth were divided in four groups (n = 10): G1 (ARC)-fiber post cemented with resin cement RelyX ARC; G2 (ARC+Z350)-relined fiber post cemented with RelyX ARC; G3 (U200)-fiber post cemented with self-adhesive cement RelyX U200; G4 (U200+Z350)-relined fiber post cemented with RelyX U200. The roots were sectioned in six 1.2-mm slices and the push-out test was performed. Data were analyzed by three-way analysis of variance (ANOVA), and Tukey's test (a = 0.05). For the conventional resin cement, there was no significant difference between groups G1-ARC (15.5 ± 3.8) and G2-ARC+Z350 (16.1 ± 4.5). For the self-adhesive cement, the results revealed higher BS values for relined posts G4-U200 + Z350 (19.9 ± 7.9) as compared to non-relined posts G3-U200 (14.4 ± 4.5). For both cements, in groups of relined posts, the apical and the cervical thirds presented similar BS. Relining enhances the performance of the self-adhesive resin cement, and the interaction between relining and root third influences the BS to the conventional resin cement.
Subject(s)
Dental Bonding , Post and Core Technique/instrumentation , Resin Cements/chemistry , Animals , Bisphenol A-Glycidyl Methacrylate/chemistry , Cattle , Cementation/methods , Composite Resins/chemistry , Dental Materials/chemistry , Dental Pulp Cavity/ultrastructure , Dentin/ultrastructure , Glass/chemistry , Polyethylene Glycols/chemistry , Polymethacrylic Acids/chemistry , Random Allocation , Root Canal Preparation/methods , Stress, Mechanical , Surface PropertiesABSTRACT
OBJECTIVE: To evaluate the effect of 3% phosphate ascorbyl gel (PA) in different times onto the microshear bond strength of composite resin (CR) to bovine enamel treated with 35% hydrogen peroxide (HP). MATERIALS AND METHODS: Thirty enamel blocks of bovine incisors were made and divided into 5 groups (n = 6) with three specimens per group (n = 18), according to treatment: G1= No bleaching + CR; G2 = HP + CR after 15d; G3 = HP + CR after 24 hours; G4 = HP + PA (15 min) + CR after 24 hours; G5 = HP + PA (2 hours) + CR after 24 hours. The resin cylinders were made by Tygon matrices. Microshear bond strength test was performed using universal testing machine with a 50N load at a speed of 0.5 mm/min. Fracture modes were assessed by a stereomicroscope 40 ×. Microshear bond strength values were submitted to the analysis of variance (ANOVA) one-way and Tukey test (p < 0.05). RESULTS: G1 had significant results when compared to G3 and G5 (p < 0.01). However, G2, G3, G4 and G5 have showed no significant differences among groups (p > 0.05). Failure modes were categorized into adhesive (90%) and mixed (10%). CONCLUSION: The use of 3% phosphate ascorbyl gel for 15 minutes was able to improve bond strength of composite resin to bleached bovine enamel, but when 3% phosphate ascorbyl gel was applied during 40 minutes it negatively interfered in the adhesion of the resin to bleached bovine enamel.
Subject(s)
Antioxidants/chemistry , Ascorbic Acid/analogs & derivatives , Composite Resins/chemistry , Dental Bonding , Dental Enamel/ultrastructure , Dental Materials/chemistry , Hydrogen Peroxide/pharmacology , Tooth Bleaching Agents/pharmacology , Animals , Ascorbic Acid/chemistry , Cattle , Dental Bonding/methods , Dental Enamel/drug effects , Dental Stress Analysis/instrumentation , Hydrogen Peroxide/chemistry , Light-Curing of Dental Adhesives/methods , Materials Testing , Resin Cements/chemistry , Shear Strength , Stress, Mechanical , Surface Properties , Temperature , Time Factors , Tooth Bleaching Agents/chemistry , Water/chemistryABSTRACT
Aim: To evaluate the cephalometric characteristics of Class III malocclusion in Caucasian Brazilian subjects. Methods: The sample comprised 71 lateral cephalograms of individuals not previously submitted to any orthodontic treatment. The Class III group (experimental group) comprised 37 patients with bilateral Class III molar relationship and ANB lower than 1 degree, with a mean age of 21.76+3.89 years (13 males and 24 females). The Class I group (control group) consisted of 34 patients with bilateral Class I molar relationship, ANB angle higher than or equal to 1° and lower than 3°, with a mean age of 21.88+3.5 years (12 males and 22 females). Dental, skeletal and soft tissue measurements were compared using the t test for independent samples. Results: The results demonstrated that the Class III individuals showed significant differences in the cephalometric characteristics, except in vertical skeletal variables. The angular variables (SNA, SNB, ANB, SND, 1.1, 1.NA, 1.NB, IMPA, NA.Pog, H.NB) and the linear variables (Pog-Nperp, Co-Gn, 1-orbit, 1-NA, 1-NB, 1-NPog, 1-ANperp, FN-Pog, H-nose, Pog-NB, E menton) demonstrated statistically significant differences between groups. Conclusions: In Class III group, subjects presented maxilla with normal size, yet retruded in relation to the anterior cranial base; protruded mandible with increased size; and concave skeletal and soft tissue profiles. The maxillary incisors were protruded and buccally tipped, and the mandibular incisors were retruded and lingually tipped. Higher prevalence of mandibular prognathism (67.6%) was observed in the Class III group.
