elham romoozi

Tooth decay is the most common chronic disease of man in the world and dentists should receive the capability to accurately diagnose of tooth decay during the training courses. In addition to clinical examination, the panoramic view and intraoral radiography is usually used for the caries detection. Therefore, the detection of caries on X-ray images can have a role in treatment planning.
In this analytical study, 10 panoramic radiographies that randomly selected, separately given to 30 senior dental students and 2 professors (in order to determine the gold standard). Data were analyzed using SPSS 17 software, diagnostic tables and indexes were prepared and the results were analyzed by Kappa test. Moreover, in order to determine the agreement between the professors and students about the depth of the decay the weighted kappa coefficient was used.
The kappa value about detection of presence or absence of proximal caries between professors and students's diagnosis was 0.428 (P value=0.001). Diagnostic sensitivity, specificity, positive predictive value and negative predictive value obtained by students in caries detection were %47, %91.9, %63 and %85.3, respectively. Coefficient of agreement in detection of depth diagnosis obtained by professors and students was 0.361(p value=0.000).
The diagnostic capability of senior dental students about caries detection was fair and depth diagnosis was slight.

Considering importance of recognizing the position of incisive canal before inserting intraosseous implants and bone harvesting from the symphysis and to preventing from adverse effects after these surgeries, using appropriate imaging method is essential and necessary. Due to the high accuracy measurement and high quality of CBCT and also low received dose to patient the aim of this study was to evaluate and recognize the position of incisive canal using cone beam computed tomography (CBCT).
In this study, good quality CBCT mandible image of 60 patients including 32 women and 28 men with average ages of 41.3±2.5 were observed for diagnosing and recognizing the position of mandibular incisive canal using three observers separately. Data were statistically analyzed using SPSS software (version 20.0 for Windows, Chicago, IL, USA) and Chi-square and Fisher's exact tests.
Horizontal and vertical assessment was independent from the sex of patients. The incisive canal was recognizable in 89.8 percent of specimens. In vertical dimension, in 57.5 percent of specimens the canal was observed in the inferior one third and in 32.25 percent in the medial one third. In horizontal dimension, in 14.75 percent of specimens the canal was observed in the buccal one third, 52.75 percent in the medial one third and 22.25 percent in the lingual one third.
The quality of CBCT imaging and its accuracy and resolution can play an important role in the differentiation and determination of the position of incisive canal.

Bone assessment is essential for diagnosis, treatment planning and prediction of prognosis of periodontal diseases. However, two-dimensional radiographic techniques have multiple limitations, mainly addressed by the introduction of three-dimensional imaging techniques such as cone beam computed tomography (CBCT). This study aimed to assess the accuracy of CBCT for detection of marginal bone loss in patients receiving dental implants. A study of diagnostic test accuracy was designed and 38 teeth from candidates for dental implant treatment were selected. On CBCT scans, the amount of bone resorption in the buccal, lingual/palatal, mesial and distal surfaces was determined by measuring the distance from the cementoenamel junction to the alveolar crest (normal group: 0-1.5mm, mild bone loss: 1.6-3mm, moderate bone loss: 3.1-4.5mm and severe bone loss: >4.5mm). During the surgical phase, bone loss was measured at the same sites using a periodontal probe. The values were then compared by McNemar’s test. In the buccal, lingual/palatal, mesial and distal surfaces, no significant difference was observed between the values obtained using CBCT and the surgical method. The correlation between CBCT and surgical method was mainly based on the estimation of the degree of bone resorption. CBCT was capable of showing various levels of resorption in all surfaces with high sensitivity, specificity, positive predictive value and negative predictive value compared to the surgical method. CBCT enables accurate measurement of bone loss comparable to surgical exploration and can be used for diagnosis of bone defects in periodontal diseases in clinical settings.

Resin cements, regardless of their biocompatibility, have been widely used in restorative dentistry during the recent years. These cements contain hydroxy ethyl methacrylate (HEMA) molecules which are claimed to penetrate into dentinal tubules and may affect dental pulp. Since tooth preparation for metal ceramic restorations involves a large surface of the tooth, cytotoxicity of these cements would be more important in fixed prosthodontic treatments. The purpose of this study was to compare the cytotoxicity of two resin cements (Panavia F2 and Rely X Plus) versus zinc phosphate cement (Harvard) using rat L929-fibroblasts in vitro. In this experimental study, ninety hollow glass cylinders (internal diameter 5-mm, height 2-mm) were made and divided into three groups. Each group was filled with one of three experimental cements; Harvard Zinc Phosphate cement, Panavia F2 resin cement and Rely X Plus resin cement. L929- Fibroblast were passaged and subsequently cultured in 6-well plates of 5×105 cells each. The culture medium was RPMI_ 1640. All samples were incubated in CO2. Using enzyme-linked immune-sorbent assay (ELISA) and (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) (MTT) assay, the cytotoxicity of the cements was investigated at 1 hour, 24 hours and one week post exposure. Statistical analyses were performed via two-way ANOVA and honestly significant difference (HSD) Tukey tests. This study revealed significant differences between the three cements at the different time intervals. Harvard cement displayed the greatest cytotoxicity at all three intervals. After 1 hour Panavia F2 showed the next greatest cytotoxicity, but after 24-hours and one-week intervals Rely X Plus showed the next greatest cytotoxicity. The results further showed that cytotoxicity decreased significantly in the Panavia F2 group with time (p<0.005), cytotoxicity increased significantly in the Rely X Plus group with time (p<0.001), and the Harvard cement group failed to showed no noticeable change in cytotoxicity with time. Although this study has limitations, it provides evidence that Harvard zinc phosphate cement is the most cytotoxic product and Panavia F2 appears to be the least cytotoxic cement over time.