Scanning electronic microscopy analysis of the apical surface after of root-end resection with different methods.

To compare the time dispensed and the surface characteristics when a root-end resection was performed with a surgical ultrasonic device (VarioSurg, NSK, Japan) or with a Zekrya bur. Forty distal roots of freshly extracted mandibular molars were selected and divided into four different groups: (G1) stainless steel insert with ultrasound; (G2) diamond insert with ultrasound; (G3) stainless steel and diamond inserts with ultrasound, and (G4) Zekrya burs. The time required for the root-end resection was timed and the surface characteristics were evaluated via scanning electronic microscopy. The median times for the root-end resections were: 115.9 s for G1, 249.8 s for G2, 112.7 s for G3, and 7.44 s for G4, the latter presented a smoother root-end surface. There was no statistically significant difference in the comparisons between G3 group and G4 group (Zekrya burs). The other groups where the root-end resections were with ultrasonic devices proportioned a prolonged time to resection with irregular surfaces.

Evaluation of precision of length determination with 3 electronic apex locators: Root ZX, Elements Diagnostic Unit and Apex Locator, and RomiAPEX D-30.

OBJECTIVE: The aim of this study was to perform a comparative analysis of precision of 3 apex locators: Root ZX, Elements Diagnostic Unit and Apex Locator, and RomiAPEX D-30. STUDY DESIGN: Forty extracted single-rooted human teeth were selected. After endodontic access, measurement of the anatomical tooth length was visually performed by insertion of a K-file size 10 until its tip could be observed at the apical foramen with aid of a light microscope at 8x magnification. Following, the teeth were placed in a plastic box with alginate and electronically measured with the 3 apex locators at 1-mm short of the apical foramen. RESULTS: The results revealed a precision rate of 97.5% for Root ZX, 95% for Elements Diagnostic Unit and Apex Locator, and 92.5% for RomiAPEX D-30, with no statistically significant difference between them (chi-square test, P > .05). CONCLUSION: The results confirm that all these electronic devices can accurately determine the root canal length within 1 mm from the apical constriction.

Influence of embedding media on the assessment of electronic apex locators.

Third-generation electronic apex locators for root canal length determination are very reliable and are not subject to interference from the contents of the canals. This study compared the effectiveness of different embedding media for in vitro assessment of electronic apex locators. The tooth lengths of 30 extracted human mandibular central incisors were measured by introducing a size 15 K-file fitted with a silicone stop into the canal until its tip appeared through the apical foramen; the distance between the tip and stop was measured. The teeth were placed in cylindrical polyethylene tubes filled with different embedding media (1% agar, gelatin, alginate, saline, and flower sponge soaked in saline), and electronic reading was performed with the Root ZX device. Data were statistically assessed by the analysis of variance (ANOVA) and Tukey tests at a significance level of 5%. Despite the lack of statistically significant difference among the media, the flower sponge was the only medium in which the file surpassed the apex in some measurements.

Evaluation of apical cavity preparation with a new type of ultrasonic diamond tip.

This study evaluated the time, occurrence of fracture, and quality of apical cavity preparation with three different ultrasonic diamond tips: Satelec, Trinity, and a new type, CVD (chemical vapor deposition), using scanning electron microscopy (SEM) analysis. Thirty human single-rooted premolars were selected, submitted to apicectomy, and prepared with ultrasonic tips; impressions were then obtained. The presence of fractures was evaluated on the impressions, and the quality of preparation was evaluated by SEM analysis of teeth and scoring by two examiners. The group prepared with the CVD tips exhibited the shorter preparation time and did not present fractures. There was no statistically significant difference in the quality of preparation for the three tips. The three brands of ultrasonic tips produced adequate grinding without altering the morphology of the apical foramen.