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Background: Comparing the net setting time and radiopacity of an Iranian glass ionomer cement (GIC) and Fuji II (GC, Japan) according to ISO 9917-1:2007 standard. Materials and Methods: In this experimental/in vitro study, for both tests, we prepared 20 samples of Fuji II glass ionomer (self-cure restorative glass ionomer, batch number: 1608031, GC Corporation, Tokyo, Japan) and Iranian glass ionomer (Ava Tajhiz Dandan-Iran) at P/L of 2/7:1. Then, to determine the net setting time, we prepared a metal mold with dimensions of 10 mm in length, 8 mm in width, and 5 mm in height. Ninety seconds after mixing, the surface of the sample was subjected to the indenter, and the net setting time was recorded as the time elapsed between the end of the mixing and the time needle stopped making a complete circular indentation. To determine radiopacity, the specimens were poured into a mold with a diameter of 15 mm and thickness of 1 mm. Samples and a step wedge were irradiated with X-rays. Particle size analysis and Energy-dispersive X-ray spectroscopy (EDS) analysis were also done for both cements. Test results were investigated with SPSS and through independent t-test (P < 0.05). Results: The mean value of net setting time for Fuji II was 4.83 min and for the Iranian Glass ionomer was 3.83 min (P < 0.05). The mean value of radiopacity for Fuji II was 2.3 mmAL and for Iranian Glass ionomer was 1.9 mmAl (P < 0.05). Conclusion: Net setting time and radiopacity of the glass ionomers were within the range of ISO 9917-1:2007. If all properties of the Iranian cement are set appropriately in future investigations, we propose to use it instead of Fuji II GIC. This has the additional benefit of being cost-efficient as Iranian cement costs less than Fuji II cement.
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Objectives: This study aimed to assess root canal transportation of curved canals following glide path preparation by PathFile and Scout RaCe rotary systems compared with manual instrumentation with stainless steel (SS) hand files using cone-beam computed tomography (CBCT). Materials and Methods: This in-vitro experimental study was conducted on extracted human mandibular first and second molars (n=51) with 25-45° canal curvature in their mesiobuccal root. All teeth underwent CBCT and were randomly divided into three groups (n=17). In group 1, a glide path in the mesiobuccal canal was created using SS hand files to the working length. In groups 2 and 3, after canal negotiation with a #8 SS hand file, a glide path was created with PathFile and Scout RaCe systems, respectively. The teeth underwent CBCT. Pre- and postoperative CBCT scans were compared to calculate the magnitude of canal transportation at 3, 6, and 9 mm from the apex. The results were analyzed using the Kruskal-Wallis and Freedman tests (P<0.05). Results: Manual instrumentation caused significantly higher canal transportation at 3 and 9 mm from the apex compared with rotary systems (P<0.05). PathFile and Scout RaCe were not significantly different at 3 (P=0.39) or 9 mm (P=0.99). No significant difference was noted in canal transportation among the three groups at 6 mm (P=0.15). Conclusion: Scout RaCe and PathFile cause less canal transportation than manual instrumentation with SS files when used for glide path preparation in curved canals, especially in the apical third.
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INTRODUCTION: Taurodontism is an anomaly characterized by elongated crowns and consumedly apical location of the bifurcation area. This study aimed to determine the prevalence of taurodontism in molars based on digital panoramic radiographies in eight cities of Iran. METHODS AND MATERIALS: This descriptive cross-sectional study was conducted on 2360 digital panoramic radiographs taken for different treatment purposes. Demographic information of patients was recorded and radiographs were evaluated for presence of taurodont molars. The prevalence rates were calculated and the data were analyzed using SPSS software version 18 via paired t-test, chi square test and ANOVA. RESULTS: A total of 2360 panoramic radiographs (from 51.4% male and 48.6% female patients) were evaluated and the prevalence of taurodontism was reported 22.9% (22.6% in males and 23.3% in females) (P>0.05). Its prevalence was 51.67% in the right and 48.33% in the left quadrants (P>0.05), 34.1% in the mandible and 65.9% in the maxilla (P=0.000) and 79.52% in the second and 20.48% in the first molar (P=0.000). The prevalence of hypotaurodontism, mesotaurodontism and hypertaurodontism was 84.13%, 11.07% and 4.8%, respectively. CONCLUSION: The prevalence of taurodont molars was high in Iran and it was more common in the second molars and in the maxilla. Hypotaurodontism had the highest prevalence.
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PURPOSE: This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., 0°), +10°, +12°, -12°, and -10° with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. RESULTS: The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of -12°, -0.66 to -0.11 at -10°, -0.51 to +0.19 at 0°, -0.64 to +0.08 at +10°, and -0.64 to +0.1 at +12°. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. CONCLUSION: Changing the slice orientation in the range of -12° to +12° reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.
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PURPOSE: Vertical root fracture (VRF) is a common complication in endodontically treated teeth. Considering the poor prognosis of VRF, a reliable and valid detection method is necessary. Cone beam computed tomography (CBCT) has been reported to be a reliable tool for the detection of VRF; however, the presence of metallic intracanal posts can decrease the diagnostic values of CBCT systems. This study evaluated and compared the effects of intracanal stainless steel or titanium posts on the sensitivity, specificity, and accuracy of VRF detection using a NewTom VG CBCT system. MATERIALS AND METHODS: Eighty extracted single-rooted teeth were selected and sectioned at the cemento-enamel junction. The roots were divided into two groups of 40. Root fracture was induced in the test group by using an Instron machine, while the control group was kept intact. Roots were randomly embedded in acrylic blocks and radiographed with the NewTom VG, both with titanium and stainless steel posts and also without posts. Sensitivity, specificity, and accuracy values were calculated as compared to the gold standard. RESULTS: The sensitivity, specificity, and accuracy of VRF diagnosis were significantly lower in teeth with stainless steel and titanium posts than in those without posts. Interobserver agreement was the highest in teeth without posts, followed by stainless steel posts, and then titanium posts. CONCLUSION: Intracanal posts significantly decreased the VRF diagnostic values of CBCT. The stainless steel posts decreased the diagnostic values more than the titanium posts.