Comparison of the apple vinegar with other chelating solutions on smear layer and calcium ions removal from the root canal.

BACKGROUND: The action of endodontic instruments during biomechanical preparation results in smear layer formation. Removing the smear layer enhances disinfection into dentinal tubules in addition to allowing tridimensional sealing of the root canal system. AIM: This study was designed to evaluate the smear layer removal and quantify the calcium ion release resulting from final irrigation with different chelating solutions. MATERIALS AND METHODS: Fifty human canines were instrumented and the final irrigation was performed with apple vinegar, 5% malic acid, 5% acetic acid, 17% ethylenediamine tetra-acetic acid (EDTA), and distilled water (control), which were collected and analyzed by atomic absorption spectrometry to quantify the concentration of calcium ions released. Smear layer removal was assessed in the cervical, middle, and apical thirds by SEM. RESULTS: There was statistically significant difference (P < 0.001) between 17% EDTA and the other solutions with regard to smear layer removal. Apple vinegar, 5% malic acid, and 5% acetic acid promoted similar root canal cleaning. There was no statistical difference among the root canal thirds. The highest concentrations of calcium ions were obtained with 17% EDTA (P<0.001) followed by malic acid, apple vinegar, and acetic acid. Apple vinegar and acetic acid removed the smallest quantity of calcium ions. CONCLUSION: It was concluded that 17% EDTA enabled greater smear layer removal and promoted release of the highest concentrations of calcium ions than the other solutions tested.

Chitosan: a new solution for removal of smear layer after root canal instrumentation.

AIM: To evaluate, by scanning electron microscopy (SEM), the efficacy of smear layer removal using chitosan compared with different chelating agents, and to quantify, by atomic absorption spectrophotometry with flame (AASF), the concentration of calcium ions in these solutions after irrigation. METHODOLOGY: The root canals of twenty-five canines were prepared using a crown-down technique and irrigated with 1% sodium hypochlorite. The teeth were randomly divided into groups (n = 5), according to the type of final irrigation: 15% EDTA, 0.2% chitosan, 10% citric acid, 1% acetic acid and control (without final irrigation). The total volume of each chelating solution was collected from the canals and analysed by AASF for quantification of calcium ions in the solutions. Then, the roots were split longitudinally and examined by SEM for evaluation of smear layer removal in the middle and apical thirds. Cleaning scores were attributed and analysed statistically using the Kruskal-Wallis and Dunn tests. The AASF data were analysed by one-way anova and Tukey-Kramer test. A significant level of α = 0.05 was adopted. RESULTS: 15% EDTA, 0.2% chitosan and 10% citric acid had similar smear layer removal capacity with a significant difference (P < 0.05) from 1% acetic acid and the control group. There was no significant difference (P > 0.05) between the smear layer remaining in the middle and apical thirds. The highest calcium ion concentration was observed with 15% EDTA (121.80 ± 5.13) and 0.2% chitosan (104.13 ± 19.23), with no significant difference. The lowest calcium ion concentration was obtained with 1% acetic acid (25.62 ± 7.68), whilst 10% citric acid (70.38 ± 11.15) had intermediate results, differing significantly from the other solutions (P < 0.01). CONCLUSIONS: 15% EDTA, 0.2% chitosan and 10% citric acid effectively removed smear layer from the middle and apical thirds of the root canal. 15% EDTA and 0.2% chitosan were associated with the greatest effect on root dentine demineralization, followed by 10% citric acid and 1% acetic acid.

Clinical and macroscopic study of maxillary molars with two palatal roots.

AIM: To report an anatomical variation in maxillary first molars. SUMMARY: A case report is presented of a maxillary first molar requiring root-canal treatment that had two palatal roots with distinct canals and foramena at the apical level. Root-canal treatment was performed using mechanical instrumentation with NiTi files. An anatomical study on two extracted maxillary second molars with the same variation revealed their internal structure. This case demonstrates an uncommon anatomical condition and supplements previous reports of such cases affecting maxillary molars. KEY LEARNING POINTS: Clinicians should be aware of uncommon anatomical variations in maxillary molars. The majority of maxillary first molars have three roots and four canals. Maxillary molars may have two canals in the palatal root.

Evaluation of the effect of EDTAC, CDTA, and EGTA on radicular dentin microhardness.

The effect of EDTAC (ethylenediamine tetra-acetic acid plus Cetavion, an ammonium surfactant), CDTA (cyclohexane-1,2-diaminetetra-acetic acid), and EGTA (ethylene glycol-bis-(beta-amino-ethyl ether) N,N,N',N'-tetra-acetic acid) on the microhardness of radicular dentin of the cervical third of human teeth was studied. Five newly extracted maxillary incisors were sectioned transversely at the cementoenamel junction, and the crowns were discarded. The roots were embedded in blocks of high-speed polymerized acrylic resin and cut transversely into 1-mm sections. The second slice of the cervical third of the root of each tooth was sectioned and divided into four parts. Each part was placed on an acrylic disc that was used as a base for microhardness measurement. Fifty microliters of 15% EDTAC, 1% CDTA, or 1% EGTA were applied to the dentin surface. Deionized and distilled water was used as control. Dentin microhardness was then measured with a Vicker's microhardness apparatus with a load of 50 g for 15 s. Statistical analysis showed that the three chelating solutions significantly reduced dentin microhardness when compared with water; however, there was no statistically significant difference among the three solutions.

In vitro action of various carbamide peroxide gel bleaching agents on the microhardness of human enamel.

The authors verified a decrease in human enamel microhardness after application of the following carbamide peroxide gel bleaching agents for 8 hours daily for 1 week: 10% Nite White, 16% Nite White, Opalescence, Karisma Alpha and Perfect Smile. Statistical analysis showed that these agents caused a decrease in enamel microhardness. Nite White (16%) was the most effective in reducing enamel microhardness and Opalescente the least effective. Nite White (10%), Karisma Alpha and Perfect Smile fell into a statistically intermediate position.

Study of the incidence of radicular grooves in maxillary incisors.

The purpose of this investigation was to determine the incidence of radicular grooves in the upper incisors of 642 patients from the region of Ribeirão Preto, SP, Brazil. Radicular grooves, present in 3.9% of the patients, were found mainly on the lingual surface of the maxillary lateral incisor (3.0%). The maxillary central incisors showed radicular grooves on both the buccal and lingual surfaces with an incidence of 0.9%. It was not possible to relate the incidence of these grooves with race (white and negro) or with sex.

[Dimensional instability of zinc oxide-eugenol based temporary sealing materials used in endodontics]. / Instabilidade dimensional de materiais seladores provisórios à base de óxido de zinco-eugenol usados em endodontia.

The dimensional instability of temporary sealing materials based on zinc oxide-eugenol was studied in vitro by chemical reaction between an indicator solution (5% nickel sulfate) and a developing solution (1% alcohol dimethylglixime). Thermal cycling was performed (5, 37 and 60 degrees C). Zinc acetate was added to zinc oxide to test its action on dimensional instability. The materials were divided into two groups. 1) group with double sealing (gutta-percha + sealing material), and 2) group without double sealing. It was concluded that none of the temporary sealing materials tested, with or without double sealing, prevented marginal infiltration when submitted to thermal cycling. The addition of zinc acetate to zinc oxide was not effective in preventing marginal infiltration.

["In vitro" evaluation of the action of various cavity varnishes]. / Avaliação "in vitro" da ação de diversos vernizes cavitários.

The authors studied in vitro the capacity of FORP-USP cavity varnishes, COPALAINE (Prodonto), COPALITE (H. J. Bosworth Co.), CAVITINE (SS WHITE) and UNIVERSAL (SS WHITE) to promote impermeabilization. The tests were done by the use of filter paper and the impermeabilization was measured by the Rhodamine B stain infiltration. The FORP-USP cavity varnishes Copalaine and Copalite were more effective in promoting impermeabilization.