Journal of Dental Research, Dental Clinics, Dental Prospects
Volume:1 Issue: 1, Spring 2007

Background and aims. It is critical to have a proper knowledge of the normal anatomy of the pulp and its variations for the success of endodontic treatment. The purpose of this study was to investigate variations in the root canal system of maxillary first permanent molars in an Iranian population. Materials and methods. In this study, 137 maxillary first molars were decalcified, dye-injected, cleared and studied.Results. The results demonstrated that 37.96% of the maxillary first molars under study had three canals, 58.4% had four canals and 3.64% had five canals. Conclusion. According to the results of this study and considering variations in the root canal systems of maxillary first molars, it seems that great care should be taken in the root canal treatment of these teeth.

Background and aims. Autogenous onlay bone grafting is a common procedure for alveolar ridge augmentation. It has been suggested that the amount of healed bone after this technique would be significantly less than the initial quantity. The aim of this study was to determine the relationship between the various parameters influencing the outcome of ridge augmentation procedures. Materials and methods. Thirty-two patients, 17 males and 15 females (mean age 40 ± 8.66), requiring lateral ridge augmentation in the anterior maxilla were recruited. Bone grafts obtained from either the mandibular ramus or symphysis were grafted on the recipient site and the buccolingual dimensions of the edentulous ridge before and six months after the procedure were measured and the difference between them was considered as ridge augmentation (RA). Parameters including graft thickness (GT), graft area (GA) and donor site (DS) were also recorded. Results. Onlay bone grafts, taken from mandibular and symphysis areas, significantly increased the buccolingual dimension of the alveolar ridge (mean 1.98 ± 1.22 mm, p < 0.001). However, the mean RA by symphysis grafts was significantly greater than ramus grafts (2.49 mm vs. 1.48 mm). There was also a significant correlation between graft thickness, surface area and the amount of bone augmentationConclusion. Symphysis area provides thicker and larger grafts, which may result in a better clinical outcome in alveolar ridge augmentation.

 Malocclusion with its great hazardous effects seems to have become more prevalent in recent decades; therefore, the present study was carried out to assess the prevalence of different malocclusions among 13-15 year-old adolescents in Tabriz.

The subjects in the present study consisted of 398 adolescents aged 13-15, who were randomly selected from 5 different districts of the city. Students who had previous orthodontic treatment or extraction of any permanent teeth were excluded from the study. Angle's classification was used to describe the type of malocclusion and the evaluation of other aspects of malocclusion such as overjet, overbite and crowding were considered the minor goals of the study. The prevalence of different types of malocclusion in the population under study was estimated.

According to the results of the study, only 4% of 13-15 year-old adolescents under study had normal occlusion, whereas 51% had Class I, 21.9% had Class II [17.6% div 1, 4.3% div 2] and 17.1% had Class III malocclusion. With respect to overjet, the study revealed that 30.7% of the population under study had increased overjet, 33.9% had decreased overjet and 2% had reverse overjet. Increased overbite was observed in 40.2% of the population studied, whereas decreased overbite was found in 19.3%, deep bite was noted in 3.3% and open bite was detected in 3.3% of the studied population.

Class I malocclusion was the most prevalent, whereas Class III malocclusion was the least prevalent among adolescents aged 13-15 in Tabriz.

Background and aims. The main purpose of this study was to assess intra- and inter-examiner reproducibility of probing depth measurements with a manual periodontal probe. Materials and methods. In this study, 32 dental students in Tabriz Faculty of Dentistry with normal periodontium were evaluated. Each tooth of the upper right quadrants, except the third molars, was examined. Probing depths were measured in 6 surfaces of each tooth (mesiofacial, midfacial, distofacial, mesiolingual, midlingual and distolingual). Each patient was examined by two examiners (two periodontists) in two sessions with an interval of 7-10 days. A total of 218 teeth and 1295 surfaces were examined. Results. Intra-examiner measurements showed no statistically significant differences, while the differences of inter-examiner measurements were statistically significant. Intra-examiner reproducibility was more than the inter-examiner one. Measurements for anterior region, facial and mid-facial/mid-lingual surfaces were more reproducible than posterior, lingual and proximal surfaces. Conclusion. Probing depth measurements with a conventional probe have an appropriate reproducibility in clinical settings, although variations between examiners may affect the reproducibility, especially when great accuracy is required.

Background and aims. Retreatment of existing restorations not only requires a lot of money and time but also there is a danger of weakening tooth structure and irritating the pulp. Since awareness of the reasons for the retreatment of teeth will save the teeth from possible future failure, the aim of this study was to assess the reasons for retreatment of amalgam and composite restorations in patients referring to Tabriz Faculty of Dentistry.Materials and methods. In this descriptive study, the subjects had previously received an amalgam or a composite restoration in the Operative Department by dental students and were judged to need retreatment in their second visit. A total of 300 defective teeth were selected by simple random sampling method. The data was collected through examination and questionnaires and analyzed using chi-square test. Results. There was a statistically significant association between the type of the restorative material and the reason for retreatment (p=0.001). Conclusion. Although the reasons for the retreatment of amalgam and composite restorations were different, recurrent caries was the main reason for the retreatment for both restorative materials

Background and aims. Fluorosis is defined as a sort of enamel hypocalcification. Clinical features of fluorosis vary from thin white lines on the enamel to chalky and opaque enamel. The enamel may be destroyed after tooth eruption. Various prevalence rates have been reported in different populations. Major contributing factors are temperature, altitude and hygienic trends. The aim of this study was to evaluate the prevalence and severity of fluorosis in 5-12 year-old children in the North-Western villages of Makoo. Materials and methods. A total of 58 children aged between 5 and 6, and 421 students aged between 7 and 12 from the North-Western villages of Makoo were selected. Dean Index was used to evaluate the prevalence of fluorosis in the primary and permanent dentition. To compare the severity of fluorosis in the maxilla and mandible and also to assess the coordination rate of fluorosis in the left and right sides of the jaw, TF Index was used. TSIF was used to compare fluorosis rate in different tooth surfaces. Discoloration prevalence and rate were compared between maxillary and mandibular incisors. Chi-square test and t-test were used to analyze the results. Results. Fluorosis rate in the primary and permanent dentition was 100%. According to TF Index, the highest coordination rate was observed in mandibular incisors and the least was observed in maxillary second molars. The difference in the severity of fluorosis between maxilla and mandible was statistically significant (p< 0.05). Discoloration rate increased in maxillary central incisors with age. Conclusion. Very high prevalence rate of fluorosis in the primary and permanent teeth in the North-West of Makoo revealed a major regional problem; therefore, preventive strategies such as informing people of improper use of fluoride-containing supplements and reduction of the fluoride content of drinking water are suggested

Background and aims. Dental handpiece is a source of contamination because it is in constant touch with the oral cavity. Sterilization does not seem to be sufficient to prevent penetration of microorganisms into air and water lines of the unit, because negative pressure developed by valves (which are placed in water outlets) and post shut-off inertial rotation of handpiece result in water and debris being sucked into air and water outlets of dental unit. The aim of this study was to compare dental unit contamination following use of clean head system handpieces and conventional handpieces. Materials and methods. Twenty-two dental units in the Department of Pediatric Dentistry in Shahid Beheshti Faculty of Dentistry were used for the purpose of this study. A 1.5×108 cfu/mm3 concentration of Staphylococcus epidermis (SE) was used to contaminate the air and water outlets of dental units. Ten clean head system handpieces and 10 conventional handpieces were used for 30 seconds in the above-mentioned suspension. Microbial samples were collected from the air and water lines. Culturing and colony counting procedures were carried out. Data was analyzed by t-test; a value of p< 0.01 was considered significant. Results. Results demonstrated a significantly lower SE contamination in water outlets following the use of clean head system (p< 0.01). Conclusion. A lower tendency of clean head system handpieces to transmit SE compared to conventional system makes them a better choice for infection control.

Background and aims. The aim of this study was to evaluate x-ray protection methods in dental offices in Tabriz. Materials and methods. In this study 142 dental offices were evaluated. A questionnaire-based method was used. The data was analyzed by descriptive methods. Results. The least commonly used methods were leaded walls (4.9%) and film badges (16.9%) and the most commonly used methods were lead partitions (67.6%) and position-distance rule (68.3%). The most commonly used patient protection devices were E-speed films (84.5%) and long collimators (66.2%). The least commonly used methods, in this respect, were automatic processors (2.1%) and rectangular collimators (0%). Conclusion. Regarding protection methods for the patient, results did not conform to international standards. Mostly, manual processing was used, resulting in extra radiation dose to patients. The methods which reduce the received dose of patients were disregarded in offices compared to educational centers, necessitating optimization of educational programs in these fields.