The use of NiTi rotary files is an option for root canal instrumentation in primary teeth.

Objective: The aim of the present work was to morphometrically evaluate collagen in carious lesions sealed with calcium hydroxide, adhesive systems, glass ionomer cement, and an antibacterial cement. Study design: Samples of infected and affected dentin were stained with Sirius Red (SR). The areas intensively stained with SR were delimited, and the percentage of these areas was measured by blind calibrated examiners. The mean results were subjected to the Kruskal-Wallis test. Results: The affected dentin sealed with Ca(OH)2 showed a better organization of the collagen in relation to the adhesive systems Prime & Bond (p= .0159) and Adhese (p<0.0001). The affected dentin sealed with Prime & Bond promoted better increase of organized collagen areas in relation to Adhese (p = 0.0004). The infected dentin sealed with glass ionomer cement (p = 0.0018) or antibacterial cement (p = 0.0004) brought a significant increase in the organized collagen areas. Conclusions: Ca(OH)2 is indicated to seal affected dentin and glass ionomer cement and antibacterial cement may be used for treatment of infected dentin. The addition of antibiotics did not influence the restoration of the infected dentin.

Objective: The guidelines of minimum intervention recommend the maintenance of the affected dentin; in the other hand, there are few methods able to analyze the presence of intratubular collagen. The objective of this study was to assess the collagen structure in carious dentin. Study design: Ten collected samples of infected and affected dentin were stained with hematoxilin-eosin (HE) and Sirius Red (SR). The areas intensively stained with SR were delimited and the percentage of these areas was measured by double-blind calibrated examiners. The mean results were subjected to the t-student test. The amount of dentinal tubules and their area (pixels) were evaluated by HE, and subjected to the Mann Whitney test. Results: The mean of dentinal tubules in the infected dentin was 213.22 and in the affected dentin it was 120.85 (p<0.05). The mean area of dentinal tubules in the infected dentin was 1175.16 and in the affected dentin was 1420.70(p>0.05). The percentage of intratubular organized collagen in the infected dentin was 12.71% and in the affected dentin it was 32.37% (p<0.05). Conclusions: The histological evaluation of the collagen is a reproducible method to perform the morphometry in carious dentin and the affected dentin presents structured collagen areas where reorganization is possible.

There are few researches in literature that mention the use of the apex locator in deciduous teeth and working length is obtained through radiographies. Objective: The purpose of this research was to compare the radiographic and the electronic method to obtain the working length in deciduous molars. Material andmethods: Twelve molar teeth were used. The specimens in the visual method had their root length measured through the passive insertion of a 10 K-file with a silicone stop within root canal until its tip was seen at the apical foramen. The working length was measured through radiographs or using the apex locator Root ZX II. The mean between the examiners was submitted to the variance analysis (ANOVA). Results: Statistically significant differences were found between the visual method and the radiographic method (p < 0.001). There was no significant difference between the working length measurements in visual method and those obtained with the apex locator (p = 0.1319). Conclusion: The apex locator is indicated as a clinical implementation for endodontic treatment in primary teeth.