Effect of the sodium hypochlorite and citric acid association on smear layer removal of primary molars

This study aimed to assess the capacity of a sodium hypochlorite and citric acid (CA) association (the latter at different concentrations) in removing coronal smear layer (SL) of primary teeth. For this purpose, the pulp chamber roof and floor of 28 primary molars were removed to obtain enamel and dentine disks. SL was produced on the internal walls of the disks using high-speed drills. The disks were irrigated with 1% sodium hypochlorite and citric acid at different concentrations (CA-4%, CA-6%, CA-8% and CA-10%), and with 0.9% sodium chloride. The samples were split and observed under SEM. Scores were attributed to the obtained photomicrographs, according to the amount of SL present. It was noted that all the tested concentrations of citric acid used after the sodium hypochlorite were capable of removing SL. The results were analyzed by the Kruskal-Wallis test, and there was no significant statistical difference among the scores of the groups tested. However, it was observed that CA-8% and CA-10% caused peritubular dentine destruction, and that CA-4% presented a larger number of samples with dense SL. Based on these results, 6.0% citric acid in association with 1% sodium hypochlorite is suggested as auxiliary chemical substances for primary teeth irrigation.     

Avulsion of permanent lower central incisors: esthetic-functional solution

Abstract –  This short communication reports a clinical case of a 11-year-old girl, who underwent an avulsion of the lower left lateral incisor and who sought delayed treatment. The treatment was a combined technique with polyethylene fibers and composite resins to create a fixed partial denture, which is a low-cost solution and presents a good esthetic-functional result. The technique is described and the success of its use in appropriately recommended cases is confirmed.     

Palpation and pressure pain threshold: reliability and validity in patients with temporomandibular disorders

This study assessed the interexaminer reliability and validity of palpation (PA) and pressure pain threshold (PPT) of the temporomandibular joint (TMJ) and the masseter and temporalis muscles in patients with temporomandibular disorders (TMD) and asymptomatic controls. Eighty (80) subjects were distributed into two groups: Group 1 consisted of 40 TMD patients with muscular and joint pain selected by RDC/TMD Axis I; and Group 2 (control) with 40 asymptomatic individuals. Training and calibration of examiners was undertaken prior to testing. Mean reliability values were 0.64 and 0.78 (PPT), and 0.59 and 0.75 (PA), for patients and controls, respectively. Results showed statistically significant differences (p<0.001), for PA and PPT among TMD patients compared with the control. The results also showed acceptable specificity values (above 0.90), although sensitivity had low values. The tests had low diagnostic validity to discriminate between patients and controls, with low positive predictive values (PPV).     

Histomorphometric analysis of rat alveolar wound healing with hydroxyapatite alone or associated to BMPs

Several materials and techniques have been proposed to improve alveolar wound healing and decrease loss of bone height and thickness that normally follow dental extraction. The objective of this research was the histologic analysis of bone morphogenetic proteins implanted into dental alveoli of rats after extraction. A total of 45 adult male Wistar rats were divided into three groups of 15 animals each: control (no treatment), implanted with pure hydroxyapatite (HA, 3 mg) and implanted with hydroxyapatite plus bone morphogenetic proteins (HA/BMPs, 3 mg). Five animals from each group were sacrificed at 7, 21 and 42 days after extraction for the histometric analyses of the osteoconductive potential of hydroxyapatite associated or not with BMPs. After dissection, fixation, decalcification and serial microtomy of 6-micron thick sections, the samples were stained with hematoxylin-eosin for histologic and histometric analyses. Both HA and HA/BMPs caused a delay in wound healing compared to control animals, evaluated by the percentage of bone tissue in the alveoli. The treatment with HA/BMPs had the greatest delay at 21 days, even though it produced values similar to the control group at 42 days. The materials did not improve alveolar repair in the normal period of wound healing and the association of HA/BMPs did not have osteoconductive properties with granulated hydroxyapatite as the vehicle.     

Clinical evaluation of a nanofilled composite in posterior teeth: 12-month results

This study compared the clinical performance of a nanofilled resin composite for posterior restorations with 2 microhybrid and 1 packable composite after 12 months of clinical service. Forty-two patients with at least 5 Class I or II restorations under occlusion were enrolled in this study. A total of 148 restorations were placed, 25% for each material (Filtek Supreme, Pyramid, Esthet-X or Tetric Ceram). Two calibrated operators placed all restorations, according to the manufacturers' instructions. One week later, the restorations were finished/polished. Two independent examiners evaluated the restorations at baseline and after 12 months according to the USPHS modified criteria. All patients attended the 12-month recall and 148 restorations were evaluated. Friedman repeated measures analysis of variance by rank and Wilcoxon sign-ranked test for pair-wise comparison was used for data analysis (alpha=0.05). All materials showed only minor modifications, and no differences were detected between their performance at baseline and after 12 months. After 1 year, the nanofilled resin composite showed similar performance to the other packable and microhybrid resin composites.     

Morphometric and microscopic evaluation of the effect of solution of acetazolamide as an intracanal therapeutic agent in late reimplanted rat teeth

Abstract –  The use of substances that inhibit root resorption may be an alternative for cases of unsuccessful reimplants. Hence, the purpose of this study was to test a solution of acetazolamide, a resorption inhibitor, as an intracanal therapeutic agent for late reimplanted teeth. Thirty rat maxillary right central incisors were avulsed and kept dry for 30 min. The teeth were instrumented, and the root surfaces treated with 1% hypochlorite solution followed by application of 2% sodium fluoride. Thereafter, the teeth were divided into two groups according to the intracanal dressing: Group I, solution of acetazolamide and Group II, calcium hydroxide paste. Teeth were then reimplanted in their respective sockets. The animals were killed at 15, 30, and 60 days after reimplantation and the samples processed for morphometric and microscopic analysis. The results showed that calcium hydroxide paste limited root resorption, even though not avoiding it. In contrast, no root resorption was observed after 60 days in the acetazolamide group, confirming the efficacy of the substance in inhibiting root resorption.