Journal of Mashhad Dental School
Year:2012 | Volume:36 | Issue:2 (81)|Papers Count:12

Introduction: Timing is an important factor in orthodontic treatment planning. Skeletal age is a standard indicator for determining optimum time for treatment. On the other hand, in clinic the phases of the dentition (deciduous, early and late mixed, permanent) have often been used for treatment timing, investigations of the different outcomes of treatment protocols at earlier vs later stages of development. Considering the importance of this issue and to evaluate it in the Iranian adolescents, the purpose of this study was to evaluate the relation between clinical phases of dental eruption and the skeletal maturity stages by cervical vertebrae method (CVM).Materials & Methods: Panoramic radiographs and lateral cephalograms of 100 boys and 100 girls were used. For determination of the Phases of dentition, Vander Linden method and for the skeletal maturity, CVM were used. The relationship between the skeletal maturity (stages in CVM) and the phases of the dentition was evaluated statistically by means of indicators of diagnostic tests and spearman’s rho analysis.Results: Spearman’s rho analysis indicated a relatively strong correlation of 0.775 (P<0.001); The early mixed dentition phase was a valid indicator of prepubertal stage (CS1), but the late mixed and early permanent dentitions were not valid indicators for the diagnosis of the onset of the pubertal growth spurt (CS3).Conclusion: In comparison with a reliable indicator of skeletal maturity (CVM), the dentition phases perform poorly in the detection of the onset of the pubertal spurt in skeletal growth.

Introduction: Acrylic teeth properties in complete denture prostheses are important in prosthesis survival. In this regard, tooth tensile bond strength with denture base is very important. The purpose of this study was to compare tensile bond strength of three kind of artificial teeth to denture base manufactured in Iran with a kind manufactured in Italy.Materials & Methods: In this experimental in vitro study, four kind of artificial teeth (Italian Ivoclar, Yaghoot, Herasit plus and Acradent) were used. Nine anterior and premolar teeth were selected and were prepared as Cylinders with 4mm diameter. Through flasking, toothbase was bonded to heat-cured acryl. Samples were thermocycled for 2500times (5°C-55°C) and then were put in plastic pipes and under stretch to fracture by Zwick Z250 instrument. The data were analysed by One- Way ANOVA and Tukey test.Results: Mean tensile bond strength was 260N for Ivoclar, 195N for Herasit, 124N for yaghoot and 54N for Acradent.Adhesive fracture percentage was 100% for Acradent, 60% for Ivoclar, 50% for yaghoot and 35.7% for Herasit. The rest was for cohesive fracture.Conclusion: The highest tensile bond strength was seen with Ivoclar followed by Herasit, Yaghoot and Acradent respectively.

Introduction: Proper and prompt diagnosis of oral mucosal diseases improves their prognosis level and therapy, but unfortunately these lesions are often misdiagnosed because of their clinical features resemblance. General dentists are important in early diagnosis and treatment of common oral diseases, therefore assessing their knowledge and practice is crucial. The aim of this study was to assess knowledge and skill of general dentists toward common oral lesions in Khorasan Razavi Province.Materials & Methods: A cross-sectional survey was conducted on 260 dentists using an illustrated questionnaire. Knowledge and diagnostic skill of oral diseases were assessed and the responses were analyzed by SPSS software.Results: Of the 260 dentists surveyed, 257 responded. The mean knowledge score of the dentists working in the city of Mashhad and other cities was 3.03 and 2.94; and the average of diagnostic skill was 2.024 and 1.97, respectively.Conclusion: There was no significant difference between two groups regarding knowledge score but the difference was significant in diagnostic skill. General dentists working in the city of Mashhad had better results in diagnostic skill significantly. Considering the overall low diagnostic skill score, it is recommended to schedule more workshops toward common oral diseases for general dentists.

Introduction: Radicular cystsand periapical granulomas are the most common periapical inflammatory lesions. However, the role of cellular immunity and microvesselsin their pathogenesis remains unknown. The aim of this study was to evaluate the mast cell density (MCD), mircovessel density (MVD) and investigating the correlation between their densities with each other in the above mentioned lesions.Materials & Methods: In this descriptive cross-sectional study, 40 paraffin blocks of mentioned lesions were selected from achieves of School of Dentistry, Babol University of Medical Sciences. Three sections were prepared from each block and stained by hematoxylin-eosin, toluidine blue, and immunohistochemically for CD34 to determine the score of inflammation, presence of mast cells and degranulatedmast cells (DMCs), and MVD, respectively. The correlation between MCD and either inflammatory infiltrate or MVD was evaluated. Data analyzed by t student, Mann-Whitney and Spearman test.Results: Mast cells were present in all periapical inflammatory lesions; 15.4±14.8 for MCD, 7.2±6.1 for DMCs, and the ratio of DMCs to total number of MCs was 0.354±0.166 and 14.8+4.44 for blood vessel density in radicular cyst and 8.52±6.75, 2.91±2.1, 0.196±0.194 and 13±8.02 in periapical granulomas, respectively. There was a positive correlation between MCD and MVD in radicular cyst (P=0.03, r=0.341), but not in periapical granulomas (P=0.6, r=0.124). MCD and MVD increased with the score of inflammation in radicular cyst (P=0.001, r=0.7) and periapical granuloma (P=0.012, r=0.54).Conclusion: Mast cells and microvessels play a role in pathogenesis of periapical inflammatory lesions. In this study, the density of mast cells and DMCs in radicular cyst was higher than periapical granulomas, but no difference was observed regarding MVD in periapical inflammatory lesions. It seems that the relationship between MCD and MVD is different based on the clinical stage of periapical inflammatory lesions.

Introduction: Root canal irrigants could change the structure of root dentin and affect the posts retention the purpose of this study was to compare the effects of three different endodontic irrigants on the retention of quarts fiber posts cemented by different resin cements.Materials & Methods: In this in-vitro study, 10 mm long post spaces were prepared in root canals of 120 premolars after endodontic therapy and cutting the crowns at the cementoenamel junction. The teeth were randomly divided into four equal groups based on the irrigants as follows: distilled water, 2% chlorhexidine, 0.25% iodine and 1% NaOCl. Quarts fiber posts were cemented by Panavia F2. Samples were stored at 370c and humidity of 100% for one week. After thermocycling, the retention of fiber posts were measured by tensile test and modes of failure were reported. Data were analyzed by One-Way ANOVA, Tukey and Fisher's exact tests.Results: The mean and standard deviation of the posts retention were 367.08±63.07, 377.59±72.02, 363.11±68.53 and 342.89±74.94 for distilled water, chlorhexidine 2%, iodine 0.25% and sodium hypochlorite, respectively. One-way ANOVA showed that there was a significant difference among the groups (P<0.001). The results of Tukey test showed that posts retention was significantly higher after rinsing by chlorhexidine (P<0.01) Conclusion: According to the results of this study, chlorhexidine rinse had a favorable effect on retention of posts cemented by resin cement.

Introduction: One of the factors that can affect dental caries is the type of diet. So, this study was designed to evaluate the correlation between diet, social factors and dmft in primary school children of Tehran in 2009 and 2010.Materials & Methods: Eight handred and twenty primary school children of 6-12 years old (boys and girls) in Tehran were randomly selected in this descriptive study and after filling out the forms, underwent dental examinations. The data were analyzed by chi-square and logistic regression tests.Results: The Average dmft in school children was 2.9±1.81, which had a significant correlation with history of pain, dental visit and frequency of brushing (P=0.0281, 0.0119 and 0.0128), respectively, but there was no significant correlation between tendency for dental visit and dmft (P=0.831). Also, dmft was affected by history of pain, dental visit & frequency of brushing using regression values of 1.688, -0.893 & -0.593, respectively. There was a significant correlation between consumption of cariogenic diet and dmft. (P=0.0234) Number of siblings and mother's and father's educational stata also had significant correlations with dmft (P=0.0193, 0.0246, 0.0208 respectively). Number of siblings also had a significant relationship with cariogenic diet and mother's and father's educational stata had significant relationships with the type of diet, respectively (P=0.0319, 0.0257, 0.0197).Conclusion: Oral health care, history of pain and cariogenic type of diet had direct effect on the rate of dmft. Likewise, dmft increased with increase in the number of siblings and lower level of parents' educational status.

Introduction: Odontogenic tumors constitute an important aspect of oral and maxillofacial pathology. Frequency of odontogenic tumors varies in different societies but no study has been done in Zahedan so far. The purpose of this study was to achieve the sex, location and age distribution of odontogenic tumors and frequency of each one in a period of ten years.Materials & Methods: In this study, documents in archive of maxillofacial pathology department of Zahedan dental school, Khatamolanbia, Tamin ejtemaei Hospital and private laboratories were reviewed from 2000 to 2010. Data about age, sex, location of tumors and relation with impacted tooth were extracted and were submitted in the forms.Results: In this study, among the 1125 cases of the oromaxillofacial lesions, 50 cases of odontogenic tumors were found.Among the different tumors, keratocyst odontogenic tumor (KOT) was the most common odontogenic tumor (48%), followed by ameloblastoma and odontoma with frequency of 24% and 12%, respectively. There were no cases of malignancy. The incidence of these lesions was 52% in women and 48% in men. The most common location of tumors was posterior of mandible and tumors were more frequent in the third decade of life. In 12 cases, the lesions were accompanied by impacted teeth.Conclusion: In this study the most frequent tumors were KOT, Ameloblastoma and odontoma respectively.

Introduction: The aim of the present study was to evaluate the dental student's concepts about dental implant education which can be used in dentistry doctorate curriculum revision and could be useful for professors of periodontology, prosthodontics and maxillofacial surgery.Materials & Methods: This was an educational research which was conducted in Mashhad dental school in 2011 and 58 end year dental students were participated in this study and filled out questionnaires about dental implant education and the concepts of these students about theoretical and practical aspects of dental implant education were evaluated.Results: A total of 98.27% of the students were agreed about education of simple implant surgery so that they could put a simple implant and 87.94% of the students were agreed about education of dental implant as a single course credit and about creation of a dental educational group, 96.56% were agreed. About dental implant educational topics, the most educational need was education of principles of implant surgery followed by education of putting a simple frontal implant, and the least, was introduction and history of dental implants.Conclusions: Because of necessity of development for new sciences in order to promote health in the society, education of dental implant for general dentistry students and revision of general dentistry curriculum seems necessary.

Introduction: Lymphoma is the malignant neoplasm of lymphocytes which is divided into 2 categories: Hodgkin and Non- Hodgkin lymphoma (NHL). The occurrence of primary lymphoma in oral cavity is uncommon and comprises only 2% of all extra-nodal lymphomas. The aim of this study was introduction of a case of NHL in oral cavity, presenting the related signs and its differentiation from similar lesions.Case report: A 72 year old man referred with complaint of a swelling in left side of the face and demanding to extract the loosen tooth. The swelling had been present for one year accompanying pain and the lesion had been treated as a dental infection. The pain had subsided but swelling had slow growing after medical treatment. Intraoral examination, revealed a swelling with rubbery consistency in depth of left maxillary vestibule extending to the tuberosity. Second premolar tooth was loosen (third degree). In panoramic view, there was an ill-defined radiolucency from mesial of second premolar to distal of alveolar ridge. This tooth had floating in air view. Incisional biopsy was made under the diagnosis of salivary or mesenchymal tumor. According to histopathology and immunohistochemistry reports, lesion was diagnosed as a diffuse large B-cell lymphoma. The patient was referred to oncologist for treatment.Conclusion: As some of the signs and symptoms of oral lymphoma may be mistaken with dental infections, it is important for a dentist to detect its signs and symptoms and make in time referral.