JOURNAL OF DENTISTRY (SHIRAZ UNIVERSITY OF MEDICAL SCIENCES)
Year:2004 | Volume:4 | Issue:3 (8)|Papers Count:8

Background: Gingivitis is the most common oral disease that involves various areas of the mouth with different degree and intensity. The beginning of gingivitis is seen in age 5, and its prevalence is increased with age. There are different opinions about the involved areas that are most commonly or most severely affected in epidemiological researches. This study was designed to determine the pattern and distribution of gingivitis and to compare the prevalence and severity of gingivitis in involved areas.Materials and methods: In this investigation, 659 randomly selected cases of school children were evaluated with periodontal Russel Index. The results of this study were compared to those of others.Results: The findings showed that %43.5 of the students had gingivitis and its prevalence was more in boys than girls and more in the lower Jaw than the upper one. The prevalence and severity of the disease was more in the molar area than the incisor area and the most affected teeth were the first molars. The prevalence of gingivitis was almost similar in the right and left sides but its intensity was a little more in the right side. The most affected age was 15 years old.Conclusion: High incidence of gingivitis indicates that oral hygiene measures are poor among Booshehri school children and need much more attention and consideration.

Background: The most important factor in fabrication of a perfect crown is having a perfect margin, which matches completely with finish line preparation and has a good situation in relation to the alveolar bone crest. To control the quality of the fixed prostheses made in a dental clinic in Shiraz, there was an attempt to assess the quality of their margins. Materials and Method: Radiography was used to check this quality. Parallel periapical radiography was made from the 102 crowns and bridges after cementation and before discharging the patients. To measure the magnification, a metal ball with 4mm diameter was attached on the crowns at the line of their proximal margins before taking images. To obtain more exact and detailed information, a projector was used to increase the magnification of the images. The distance between the crown's margin and finish line in horizontal and vertical aspects and also the distance to the alveolar bone crest were measured.Results: The statistical analysis of the data revealed that in 76.5 percent of the cases the crowns had more gap in the vertical aspect than the acceptable range (50 micro meters). In 60.8 percent of the cases there was a gap in the horizontal aspect. In 11 percent of the cases, a ledge was seen in the horizontal aspect and by combining the gaps in both horizontal and vertical aspects, it was seen that, as a whole, 92.2 percent of the crowns had more gaps than the acceptable range. Also it was seen that in 77 percent of the cases in the mesial and 64.5 percent in the distal part, the crown's margin had invaded to the biologic width.Conclusion: It is concluded that it would be worthwhile to make radiographic image to check the framework, thereby important errors, which are difficult or impossible to discover by clinical examination will be shown.

Introduction: Bacteria and their by-products are the main cause of pulpal and periapical diseases. Complete debridment and disinfection of the root canal is essential in order to sustain the long term successful results following root canal therapy. This study aims at comparing the antibacterial effect of NaoCl, Thyme oil, Hydrated Calcium Oxide and Normal Saline on selected bacteria isolated from infected root canals.Materials and Methods: Bacteria were collected from 25 infected root canals of patients who had not received antibiotics. The bacteria were collected in the tubes and transferred for bacteriologic examination. Streptococcus viridance and black Pigmented Bacteroid groups were detected by specific bacteriological examination. The experimental solutions were serially diluted 8-folds in saline. A certain volume of bacteria was added to each diluted solution. After 1, 5 and 15 minutes, the solution of each tube was poled onto 3% sheep blood agar plates and incubated at 37oc for 48 hours. The grown colonies were counted and the results were recorded.Results: The results of this study showed a significant antibacterial effect of thyme oil, hydrated calcium hydroxide and sodium hypochlorite on selected bacteria even in low concentration. Normal saline did not show any antibacterial effect.Conclusion: These findings recommended further studies on other aspects such as tissue toxicity, tissue solving and biocompatibility properties of these solutions to be applied for clinical use.

Background: It is likely that the inferior alveolar nerve injury occurs following the removal of the lower third molars due to the anatomic proximity. So preoperative radiographic assessments are necessary to determine the position of the mandibular canal. Radiography is the most standard technique for assessing the anatomic relationship between the third molars and the mandibular canal. Panoramic view can help to determine the relationship and position of the mandibular canal to the mandibular third molar.Materials and Methods: 664 panoramic radiographs of the individuals aged 20-70 years who showed 1128 impacted third molars were assessed. Photos of these panoramic images were obtained with a digital camera in similar conditions. The incidence of proximity of the root tips of the third molars and mandibular canal (in range of 2 and 3 mm) was detected. Four radiological signs (deflected roots, diversion of the canal, interruption of the cortical white line of the canal and the narrowing at the canal) were recorded in both sides and in different ages.Results: From 1128 impacted mandibular third molars, %79.3 had 2 roots and %20.7 had one root. In the teeth the roots of which had a distance with the mandibular canal, the proximity was observed in females more than in males. There was no significant relationship between proximity and age. In 558 teeth, one or both roots were superimposed over the mandibular canal. In those cases, there was no statistically significant relation between superimposition and age and sex. Deflection of the root and interruption of the white line of the canal were observed in the right side more than the left side. Diversion of the canal was seen more in the LT side. Narrowing of the canal showed no difference among the patients.Conclusion: In the present research, in significant cases of impacted third molars (in both gender and in both sides) there are radio graphical signs for proximity of the mandibular canal and the root of impacted third molars, which increases the risk of inferior alveolar nerve injury.

Introduction: For proper occlusal interdigitation or coordination of arches in the finishing stage of orthodontic treatment with proper overjet and overbite would have been a proper mesiodistal tooth size ratio (Bolton analysis) between maxillary and madibular teeth. The Bolton analysis should be taken into consideration when diagnosing, treatment planning and predicting prognosis in clinical orthodontics. In this study tooth size ratio was evaluated among different malocclusion groups.Materials and Method: This study was carried out on 200 pretreatment orthodontic casts, which were chosen through selective available sampling procedure according to selective criteria's. They were classified by the Angle classification, coincided with skeletal categories.  Skeletal types were assessed by ANB angle from cephalometric analysis. All the subjects were divided into 4 groups: each group consisted of 25 males and 25 females. These groups were Cl I malocclusion, Cl II Div 1, Cl II Div 2 and Cl III. The greatest mesiodistal diameters of all the teeth on each cast were obtained except the second and third molars. The measurement was done by digital caliper with 0.01 mm accuracy. Then tooth size ratios were analyzed as Bolton described.Results: The main anterior ratio for male patients was larger than that of female patients in all groups (p<0.05), while there was no significant sexual dimorphism for overall and posterior ratios between the groups. The mean of the anterior ratio of Cl III patients was shown to be more than Cl II Div 1 amd Cl II Div 2. No statistical difference was found between Cl III and Cl I patients. Posterior and overall ratios of Cl III patients were larger than other groups. The mean overall ratio of Cl I patients was larger than Cl II Div 1, but it had no significant difference with Cl II Div 2 group.Conclusion: This study suggests that the tooth size discrepancy between the maxillary and mandibular teeth may be one of the important factors in the cause of malocclusions, especially in Cl III malocclusion.

Background: The clinical use of composite and polyacid modified composite restorative materials has greatly increased over the last few years. The chemical environment is one aspect of the oral environment which could have influenced the degradation of composite resins. The aim of this study is to evaluate the effect of acid food-simulating liquids on surface characteristics (Roughness and Hardness) of two composites and one polyacid modified composite.Materials and Methods: Twenty disks of each material (Composites Z250 and Heliomolar) and Compomer (Compo glass) were prepared (a total of 60 experimental specimens). Half of them were used for micro hardness testing and the remaining half for studying surface roughness by using Roughness tester. Each group of 30 disks was divided into two subgroups of 9 and one subgroup of 12 disks, the samples were then conditioned for one week as follows: sub groups 1 (control), 12 disk: distilled water at 37oc, sub groups 2, 9 disks: citric acid 0.02n at 37oc, sub groups 3, 9 disks: lactic acid 0.02n at 37oc. The data were analyzed using two-way ANOVA, Tukey-HSD and Tamhan test.Results: No Significant changes in the surface hardness were noted with conditioning at Z250, Heliomolar and Compo glass in distilled- water and citric acid, but in lactic acid, the surface hardness of Z250 was more than that of Compo glass while the surface hardness of Heliomolar was similar to Compo glass.Conclusion: Roughness Average (RA) and surface-hardness of all the evaluated restoratives was not significantly affected by acid food- simulating liquids.

Canines are the unique members of dental arches. They play a very important role in human and animal’s dentition. They support lip and facial muscles and in this way promote facial esthetics. In addition, the canines act as important guideposts in occlusion. Their deep overbite serves as a protective mechanism relieving the posterior teeth from excessive and potentially damaging horizontal forces during lateral excursion of the mandible. The ectopic eruption and impaction of the canine is a frequently encountered problem. The prevalence is estimated to be between 0.8 to 2.8% in the maxilla. In the maxilla, it is shown to be palatal to dental arch in about 85% of the cases. The etiology of the ectopic eruption and impaction is not well understood although, according to some speculations, it can have a multi- factorial feature as: arch length discrepancy, genetic and familial trend, delayed exfoliation of the primary canine, abnormal tooth bud’s position, trauma, etc. The diagnosis of unerupted canines involves: inspection, palpation and radiographic assessment. The ectopic canine would often require complex multidisciplinary treatment involving surgical, restorative, periodontal as well as orthodontic components. In this article, an overview of the incidence and sequelae as well as the surgical periodontal and orthodontic considerations in the management of impacted canines is presented.

Background: As conventional prosthesis's are still the most common prosthetic treatment for public, this study has been conducted to assess the communication between the dentist and dental laboratories and find the supervision of the dentists on lab works.Materials and Methods: In this descriptive, cross-sectional study, by referring to ten dental laboratories, seven basic steps of the construction of PDRs have been considered and all the necessary information was recorded in a questionnaire.Results: In %83 of the cases, RPDs were constructed on the study diagnostic casts and for %100 of the cases no border molding had been done. %83.7 of the retentive clasps was not actually retentive, but again in %83.7 of them there was some form of reciprocal component. In %96.7 of the cases, the clasp arms were fabricated on unprepared tooth surfaces. All major connectors were rigid and in %42.9 of the cases they had enough distances to gingival margins. In most cases, indirect retainers were absent or were made in wrong places. Only in 10 out of 35 distal extension cases, RPD design was considered and for the rest, no special design was observed. In only %5, guiding planes were made on prepared tooth surfaces and finally it appeared that the majority of RPDs were designed by dental technicians rather than by dentists.Conclusion: The results indicate that dentists frequently use techniques that require a minimum of appointment time. Therefore, a greater emphasis is required to be put on continuation of education for dentist, along with better and more detailed communication between the dentists and dental laboratories.