مجله دانشکده دندانپزشکی مشهد
سال سی و هشتم شماره 2 (پیاپی 89، تابستان 1393)

Smoking is a harmful habit that causes adverse effects on oral health and plays the most important role in cancer, precancerous lesions and periodontal disease. Saliva is the first fluid that is exposed to cigarette smoke. Salivary antioxidant system plays an important role in its anti-cancer potential therefore; this study was designed to compare the antioxidant content of saliva of smokers and non-smokers. In this cross- sectional study unstimulated saliva of 50 male smokers and 50 male non-smokers who were free of oral disease were collected by spitting method and total antioxidant capacity of their saliva was evaluated by FRAP method. Data were analysed by SPSS software version 21 and independed t test was used to compare the two groups. The average total antioxidant capacity of saliva in smokers and non-smokers were 489.95±203.82 and 589.48±226.05, respectively which were significantly different (P=0.008). Based on the results, smoking can reduce the total antioxidant capacity of saliva.

Pulp stone is a focal calcification in dental pulp which is commonly observed in usual dental radiographs and its clinical significance is difficulties to get access to the pulp chamber and root canal in endodontic treatment. So, this study was planned with the aim of determining the prevalence of pulp stone in patients referring to Guilan dental school and to assess its association with age, gender, tooth type, jaw, tooth status and systematic disease in this descriptive cross-sectional study, panoramic and bitewing radiographs of 373 patients referred to Guilan dental school were examined for the presence of pulp stones in the coronal portion of the pulp. Variables of age, sex and systemic disease were also recorded. Statistical analysis of the data was performed by chi-square test. The presence of pulp stone was detected in 20.9% of patients (13.9 female, 7% male) and 3.2% of the teeth. Gender and systemic diseases had no significant association with pulp stone (P>0.05).As age increased, the prevalence of pulp stones increased (P=0.025). Frequency of stone in maxilla was 56% and in mandible was 9% and the difference was significant (P=0.0001). The highest prevalence of pulp stones was in first molars of maxilla. The prevalence of pulp stone was significantly higher in sound teeth (P=0.0001). The results of the present study indicate that pulp stone is a frequent finding in molars and sound teeth and increases significantly with age. There is no significant association between pulp stone and gender or systemic disease.

Low quality of radiographic images may disturb crucial information and lead to retaking of the radiograph and unnecessary exposure to patients. Therefore، evaluation of the effect of delayed scanning and storage condition of photostimulable storage phosphor (PSP) sensors in diagnostic quality of digital images seems important. In this in vitro study، 60 radiographic images were obtained by 12 Digora PSP sensors in three storage condition; light room with lucent protective plastic، light space with dark protective plastic، dark space with dark protective plastic، and five various scanning time delay; 0، 5، 10، 15، 20 minutes. Digital radiographic images were exported to the new folder as TIFF format and presented to three observers. Kruskal-Wallis test with level of significance less than 0. 05 was used for statistical analysis. Comparing image quality in different storage conditions of PSP sensors، revealed no significant difference among the observers. There was no significant difference among different delays in scanning times for each observer. Scanning of PSP sensors with 5 to 20 minutes delay has no negative effect on image quality in diagnosis of apical portion. Black or transparent cover and dark or light storage environments were not effective in reducing the effect of delayed scanning and signal fading. An important point is the influence of training on improvement in perception and interpretation of digital radiography.

Ultrasound and color Doppler imaging، along with radiography have been introduced for diagnosing periapical lesions. This study aimed to assess the data obtained from digital radiography، ultrasound and color Doppler imaging on periapical lesions. In this descriptive cross-sectional study، patients with periapical lesions associated with anterior maxillary or mandibular teeth who were referred to endodontics department of Tehran Azad dental school were assessed. Periapical radiographs were obtained and dimensions and borders of the lesions were recorded. Ultrasound and color Doppler examinations were then performed & the images were assessed for the size، content، echogenicity and vascular supply. Findings were compared and statistically analyzed by McNemar، paired t test، Wilcoxon signed ranks test and Spearman correlation. Radiography in 20 and ultrasound in 15 patients could measure the lesions. There were inconsistency for showing borders between the two techniques (P<0. 508). There were inconsistency between the two methods in mesiodistal and suprainferior dimensional measurements (P=0. 165 and P=0. 228 respectively). In radiography، the dimensions were greater than in ultrasound and the differences were significant (P=0. 041، P=0. 005). Color Doppler and ultrasound could describe the lesions. Lesions are measured smaller in ultrasound than in radiography and in many cases ultrasound is not able to display the lesion. Color Doppler and ultrasound can be used as assisting tools for diagnosing the nature of the lesions.

CD105 is a cell membrane hemodymeric glycoprotein and the basic marker of neovascularization. Snail2 is a transcription factor and results in impaired epithelial adhesion. The purpose of this study was to compare the expression of CD105 and Snail2 in dysplastic epithelium and oral squamous cell carcinoma (SCC). In this descriptive - analytical study، a total of 40 paraffinized blocks of SCC and dysplastic epithelium were subjected to immunohistochemical staining with CD105 and Snail2. Expression of CD105 and snail2 and their correlation with other and with clinicopathological parameters were evaluated. The data were analyzed by t، Man-Whitney، ANOVA tests. The mean micro-vessel density with CD105 in SCC and dysplasia were 11. 73±5. 828 and 5±1. 892 respectively (P<0. 001). The mean micro vessel density in intra tumoral area was 7. 75±4. 329 and in peri tumoral area was 15. 7±7. 26 (P<0. 001). Average density of Snail2 in SCC was higher than that of dysplasia (P<0. 001). There was no significant relationship between age، sex، tumor location and differentiation grade، and CD105 marker but a positive correlation existed between Snail2 and differentiation grade of SCC (P=0. 007). In transformation of dysplasia to squamous cell carcinoma with increase in the expression of CD105، increased expression of Snail2 was observed. (P<0. 001، r=0. 76) The results of the present study showed the role of CD105 and Snail2 in the incidence of carcinogenesis. The direct relationship in the expression of CD105 and Snail2 supports the role of them in progression of the premalignant lesion to malignancy. Snail2 can be an effective factor in progression of oral carcinogenesis.

Internal derangements of temporomandibular joint are the most common type of joint disorders after muscle disorders and include all disorders related to incompatibility and dislocation of disc and condyle. The purpose of this study was to evaluate disc position in patients with temporomandibular joint (TMJ) clicking referring to occlusion unit of Mashhad dental school using magnetic resonance imaging (MRI) as the gold standard. Sixty-eight joints in 34 patients diagnosed with TMJ clicking were studied using MRI. Sagital MR images were obtained with 0. 5 Tesla magnetic resonance system in the open and closed mouth position to evaluate disc position in relation to the fossa. The data were analyzed using Chi-square and Fisher’s Exact tests. Disc displacements (DDs) were observed in 54. 4% of the TMJs analysed. Joints with intermediate and late clicking showed more DDs. Anterior DDs were observed in 41. 2% of the joints. The amount of DD in joints with clicking sound was significantly higher than that of those without clicking. We found that the presence of clicking sound in the clinical examination could not always predict DD. Thus، MRI presents as the gold standard for the detection of DD.

Computer technology has been started since 1960 and the presentation of electronic education in Dental Schools has been initiated since 1980-1990. Considering the importance of practical course in dental morphology and presence of learning problem issues and lack of information in Iranian society، this research was conducted on dental students. This study was conducted on 66 fourth semester dental students consisting of 3 groups of 22 each. Three practical courses (carving of maxillary canines and first premolar and mandibular second premolar)، were selected. Each of the topics was taught in two ways: traditional (control) and film (before and after the traditional teaching). At the end of the semester، final assessment and test scores of the practical Dental morphology course were analyzed by generalized estimating equations (GEE) and factors related to learning practical morphology lessons were analyzed using Wald test. According to the results of the Generalized Estimating Equations، no statistically significant differences among the groups in learning practical lessons of dental morphology were observed in the intervention and control groups (P=0. 15 and P=0. 3). Wald test showed that the number of children، the economic situation and interest to the dental morphology department was different between the groups (P=0. 025، P=0. 021، P=0. 04). Other variables examined did not have statistically singificant relationship with the learning of the teeth morphology (P>0. 05). Finally، among the three techniques implemented traditional method gained the highest score compared to the two other techniques. Traditional mothels seem to be the most suitable technique as compared to the other 2 mothels.