Objectives: The primary aim of this study was to assess the prevalence of sinus tracts in endodontically treated teeth in an Iranian population. The second aim was to seek and analyze the relationship between the clinically detected sinus tracts and factors such as sex, age, tooth type and location. Study design: A total of 728 patients` records and radiographs were reviewed of 427 females and 301 males for demographic data, preoperative pulpoperiapical status of treated teeth and the presence of sinus tract. Data were analyzed using chi-square test. Results: No significant differences were found for the prevalence of sinus tracts between two genders. Data showed that the highest prevalence of sinus tracts was in 10-19 year age group. Of 725 treated teeth, 107 teeth had sinus tracts (14.7%). Most odontogenic sinus tracts were associated with mandibular anterior teeth. Of 348 teeth with preoperative status of periapical inflammation and radiolucency, 107 teeth (30.75%) had an odontogenic sinus tract. Conclusion: Data showed that almost one in seven teeth referred for root canal treatment had a sinus tract.

Objectives: Today many clinicians use both stainless-steel hand K-files and nickel-titanium rotary files during endodontic treatment. It is of great importance for the clinician to have confidence in the accuracy of an apex locator even if these files were used interchangeably. The purpose of this in-vitro study was to evaluate the accuracy of the Raypex5 electronic apex locator using stainless-steel hand K-file versus nickel-titanium rotary Mtwo file. Study design: Twenty straight and single canals of maxillary central teeth were used. Access cavities were prepared; actual working length were determined and compared with electronic working length obtained by means of apex locator Raypex5 using stainless-steel hand K-file and nickel-titanium rotary Mtwo file. Data was analyzed by paired T-test. Results: There was no significant difference between 15/0.02 stainless-steel hand K-file and 10/0.04 NiTi rotary Mtwo file for the mean differences between actual and electronic working length (p=0.126). Conclusions: Under the conditions of this in-vitro study, Raypex5 registered more measurements in acceptable range using 15/0.02 stainless-steel hand K-file and 10/0.04 NiTi rotary Mtwo file. It is possible to use them interchangeably without compromising the working length.

Objectives: The purpose of this in-vitro study was to compare shaping ability of NiTi rotary Mtwo and FlexMaster with stainless steel hand K-Flexofile in simulated curved root canals. Study Design: Forty-five simulated canals in resin blocks were prepared with Mtwo, FlexMaster and stainless steel hand K-Flexofile (15 blocks in each group). Using pre-and post-instrumentation images, straightening of the canal curvature was determined with a computer image analysis program. Material removal was measured at 5 measuring points, beginning 1 mm from the apex. Changes of working length (WL) were also recorded. The data were analyzed statistically using paired T-test and one way ANOVA. Results: The mean material removal from the inner canal wall was different from the outer canal wall at all measuring points for each system (p < 0.0001) except for FlexMaster at WL-9 (p = 0.123) and K-Flexofile at WL-5 (p = 0.093). The mean ratio of material removal (inner/outer) at all measuring points was different for all systems except for FlexMaster and Mtwo at 3, 5 mm (p = 0.984, p = 0.242), and K-Flexofile and rotary systems at 1, 3 mm from the apex (p = 0.565, p = 0.218) (p = 0.794, p = 0.693). A mean loss of working length of 0.02 mm for Mtwo and 0.01 mm for FlexMaster and K-Flexofile was measured although the difference was not significant. Conclusions: In the apical points of the curvature (1, 3 mm), there was no significant difference between three systems. At point 5mm from the apex, K-Flexofile remained better centered, while in the coronal points (7, 9 mm) NiTi rotary systems achieved better canal geometry.

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