مجله دانشکده دندان پزشکی اصفهان
سال هشتم شماره 4 (پیاپی 32، مهر 1391)

Several studies have evaluated the effect of surgical removal of the impacted lower third molars on periodontal lesions around the adjacent second molars and the recovery of these lesions. The aim of this study was to evaluate the effect of demineralized bone protein on the recovery of periodontal lesions after third molar surgery in patients referring to the Department of Oral and Maxillofacial Surgery, Isfahan Faculty of Dentistry.

In this single-blind clinical trial, 16 patients referring to the Department of Oral and Maxillofacial Surgery, who were candidates for the bilateral surgical removal of lower third molars, were randomly selected. Inclusion criteria consisted of the lower third molar impaction and presence of second lower molars, and a mean age of 26 years. Pocket depths and attachment levels on the distal surface of second molars were measured in the case and control groups before surgery and 12 weeks post-operatively. Data in relation to means of changes were analyzed by paired t-test using SPSS software (α = 0.05).

The results of this study showed statistically significant differences in pocket depths and attachment levels before surgery and 12 weeks post-operatively each group (p value < 0.001). According to paired t-test there were no statistically significant differences in pocket depths (p value = 0.497) and attachment levels (p value = 0.155) between the two groups 12 weeks post-operatively.

Under the limitations of the present study, use of demineralized bone protein had no effect on periodontal parameters after surgical removal of impacted lower third molars.

Panoramic radiography provides a tomographic image of facial structures, with unequal magnification in different parts of the image, which is considered a disadvantage. In addition, wrong position of the patient results in some blurred images outside the image zone. The aim of this study was to evaluate the effect of a change of 10° in the position of the chin in the vertical plane on magnification of different parts of jaws on panoramic radiographs. In this descriptive cross-sectional study 6 human dry skulls were marked in the central, premolar and molar areas of the maxilla and mandible and the ramus area of the mandible by gutta-percha. Then panoramic images were taken twice from each skull in two positions by tilting them up and down for 10 degrees. The measurements on dry skulls and radiographs were carried out by two viewers independently. Data were analyzed by SPSS 11.5 using t-test and ICC (intra-class correlation coefficient) after magnification was calculated in each area (α = 0.05). In the extended position the anterior areas of the jaws exhibited the greatest magnification in both horizontal and vertical dimensions and the least effect of changing chin position was seen in the posterior area of the mandible. In the flexed position, in all the regions, the magnification in the horizontal dimension was less than one. There was a significant difference between the average magnification in both dimensions and both up and down positions and the mean magnification in the normal position (1.25) (p value < 0.05). In both extended and flexed positions, the magnification in the horizontal and vertical dimensions changes with the greatest changes in the anterior regions of jaws.

Various dental age estimation methods have been used, based on tooth development. In Cameriere method the distance of the apices of seven left permanent mandibular teeth is measured. The aim of this study was to compare dental age means estimated by Cameriere method and the means of chronological age. In this cross-sectional descriptive study, 109 panoramic radiographs of 67 females and 42 males aged 5‒15 years were assessed. The variables included the number of teeth with full development and closed apices, the distance between the inner sides of open apices in immature teeth, and the tooth lengths. To accommodate the effect of magnification and x-ray angulation, the measurements were normalized by dividing them by tooth lengths. Finally, the normalized measurements of open apices, the sum of the normalized open apices, the number of teeth with closed apices, gender and chronological age were recorded using SPSS 18 for age estimation formula. Data were analyzed by Pearson’s correlation coefficient and independent t-test (α = 0.05). Pearson’s correlation coefficient showed significant and inverse correlations between age and all the other variables. Differences between dental and chronological ages varied from -2.66 to 2.79 years. The median of chronological age was 10.67 and that of Cameriere age was 11.12 years. The difference between chronological age and estimated age was not significant (p value = 0.95). The differences between chronological and Cameriere ages were 0.73 in girls and 0.99 in boys. Estimated age was more accurate in girls (p value = 0.04). The present study indicated that Cameriere method was reliable for age estimation in our sample; also this method of age estimation was more accurate for girls than for boys.

Dental and oral hygiene is one of the most important indicators of general healthcare. Promotion of oral health in elementary school students is very important due to lack of adequate dexterity in carrying out correct brushing movements and education is needed in this age group. The aim of this study was to compare roll and scrub brushing techniques in controlling dental plaque in 8-11 year-old students referring to the Department of Community Dentistry, Isfahan University of Medical Sciences. In this clinical trial 215 elementary school students were divided into 8-9 and 10-11 age groups based on age and gender. Half of the subjects in each group were instructed the roll technique and the other half the scrub technique. The subjects brushed their teeth using the techniques instructed. O’Leary’s index was used to register the amount of plaque in each stage and compare the results. Data were analyzed with t-test and co-variance analysis. The scrub brushing technique was significantly more effective in decreasing dental plaque compared to the roll technique (p value < 0.001). Under the limitations of the present study, the scrub brushing technique was significantly more effective in decreasing dental plaque compared to the roll technique in the two age groups evaluated. Older children were more efficient in removing dental plaque. In addition, boys were more efficient than girls in removing plaque.

Congenital missing of maxillary lateral and mandibular second premolar teeth is one of the most prevalent developmental anomalies. The aim of this study was to determine the prevalence and pattern of congenital missing of maxillary lateral and mandibular second premolar teeth in patients referred to the Department of Maxillofacial Radiology, Islamic Azad University, Dental Branch of Tehran, in 2009. In this descriptive cross-sectional study, 645 panoramic radiographs of 12-25 year-old patients (314 boys and 331 girls) were evaluated in relation to missing of maxillary lateral and mandibular second premolar teeth. Data were analyzed using chi-squared test (α = 0.05). Among 645 panoramic radiographs, 56 cases were found to have missing teeth (8.7%). The prevalence of congenital missing of maxillary lateral incisors was higher than that of mandibular second premolars, with no statistically significant differences (p value = 0.17). There was no significant correlation between missing teeth and gender (p value = 0.94). No significant differences were seen in the prevalence of missing teeth between the right and left sides (p value = 1). This study showed a rather high prevalence of missing teeth in Iranian dental patients. Therefore, accurate and frequent examination of children is crucial for early diagnosis since missing can cause serious problems in esthetic and speech.

Adhesive restorations properly transmit and distribute functional stresses at the bonding interface to tooth structures and have the potential to reinforce remaining weakened tooth structures after removal of extensive carious lesions. This study evaluated the effect of a number of adhesive restorative materials on reinforcing unsupported enamel. Seventy-five extracted sound maxillary premolars collected over 3 months and stored in 0.2% thymol solution received MOD cavities; the lingual cusps were reduced up to the pulp level. The specimens were divided into five groups (n=15). In group 1 (the positive control), dentinal tissue of the buccal wall was preserved. In other groups the buccal dentin was completely removed. In group 2 (the negative control), no restorative material was used to replace the lost dentin. The removed buccal dentin was replaced with composite resin, flowable composite resin and glass-ionomer in groups 3, 4 and 5, respectively. After thermocycling, the specimens were tested in an Instron universal testing machine. Data were analyzed with ANOVA and LSD test (a < 0.05). The mean and standard deviations of fracture loads of the five groups were 122.97 ± 15.11, 44.71 ± 14.23, 78.32±17.58, 81.17 ± 19.53, and 85.33 ± 22.07 Newtons, respectively. One-way ANOVA revealed significant differences between the groups (p value = 0.00). There were significant differences in fracture loads between groups 1 and 2 and others (p value = 0.00). The difference in fracture loads between group 3 and 4 (p value = 0.678), groups 3 and 5 (p value = 0.344), and groups 4 and 5 (p value = 0.589) were not significant. It can be concluded that the three types of adhesive restorative materials in this study can reinforce unsupported enamel to a certain degree.

There are different radiographic imaging techniques used in dental treatments such as implants. Use of cross-sectional images, such as tomograms, enhances the visualization of the available bone. Tomographic images are prepared using 2 methods, linear and spiral. The aim of this study was to compare the accuracy of radiographic measurements in images taken by these two techniques. In this experimental study, 20 sites were selected on three dry human mandibles (10 sites anterior to and 10 sites posterior to the mental foramen) and radiographic images were taken by two techniques of linear and spiral tomography. The tomographic images were evaluated by two radiologists in relation to the variables of height and width of mandible. Then the mandibular bones were sectioned at the specified sites to determine the actual sizes of variables. The measurements from the tomograms were classified into 3 groups: error >+ 1 mm, error < -1 mm, and -1 mm < error < + 1 mm, and then were statistically analyzed by Pearson and chi-squared tests (α = 0.05).In addition, Cohen’s kappa coefficient was determined to evaluate inter-observer accuracy. The accuracy of radiographic measurement of linear tomography was not significantly different from that of spiral tomography, based on variable of height (p value > 0.05). Similarly, based on the variable of width, there was no significant difference between the two methods (p value > 0.05). Within the limitations of this study, the accuracy of the images taken by two linear and spiral tomography techniques is equal and acceptable compared to the real dimensions.

The soft palate is the posterior fibro-muscular portion of the palate, with a main role in velopharyngeal closure which assists in the normal functions of sucking, swallowing and pronunciation. The aim of this study was to investigate variations in the morphology of soft palate in normal subjects.

In this descriptive-analytical study 169 digital lateral cephalograms were selected from normal Iranian subjects (94 women and 75 men), with age ranges of 15-20 and 21-35, referring to a private oral radiology center in Isfahan. Morphology of the soft palate on lateral cephalograms was examined and classified into 6 types. In addition, the soft palate lengths in each type and differences in relation to age and gender were evaluated. Data were analyzed by t-test, chi-squared test and one-way ANOVA (p value > 0.05).

The morphology of the soft palate was classified into 6 types. Type 1 (leaf-shaped) was the most prevalent. There was a significant difference in the shape of the soft palate between males and females (p value = 0.02). The mean length of the soft palate in men was more than that in women (p value = 0.03). In addition, the soft palate length in type 3 (butt-like(was significantly shorter than that in other types (p value < 0.05).

The soft palate exhibits variable radiographic appearances on lateral cephalograms. Attention to these anatomic variations might assist velopharyngeal closure in patients with cleft palate, obstructive sleep apnea syndrome and speech disorders.

Health care workers and dental practitioners are always concerned about occupational transmission of human immunodeficiency virus (HIV). This study evaluated knowledge, attitudes and performance of dental practitioners in Shiraz, Iran in relation to AIDS. In this descriptive cross-sectional survey a 45-item questionnaire was distributed among 68 general and specialist dental practitioners in Shiraz. Data were analyzed by SPSS software using t-test, ANOVA and Pearson’s correlation coefficient (α = 0.05). The response rate was 88% (n = 60). The mean of dentists’ knowledge was 8.9 ± 1.9 out of 13 and the mean of dentists’ performance was 10.15 ± 3.2. The difference between males and females were not significant (p value = 0.51). Knowledge of dentists was significantly associated with age, i.e. there was a decrease in knowledge (p value = 0.03) and an improvement in performance (p value = 0.001) with an increase in age. A total of 93.3% of respondents felt an obligation to treat HIV-positive patients; 70% of dentists believed that the risk of HIV infection was high despite the necessary precautions. I relation to questions about attitude, no significant differences were observed between the respondents (p value = 0.29). Based on the results of the present study, the dental practitioners evaluated had a low level of knowledge and performance in relation to AIDS. It is necessary to improve knowledge, attitude and infection control behaviors of dental practitioners in relation to AIDS. It is suggested that more emphasis be placed on this subject in dental school curricula.

Knowledge about significant clinical, radiographic and histopathological features of odontogenic cysts and their differential diagnosis with each other and other odontogenic lesions of the oral cavity and also their treatment plan and prognosis is mandatory for dental practitioners. Therefore, in this article odontogenic cysts are reviewed according to their clinicopathologic correlation with each other, and not necessarily based on their prevalence. Review Report: This article was prepared by studying reliable textbooks and also searching Pubmed, Scopus, Google Scholar, Iran Medex, Index Copernicus and ISI references for the published data from 1962 to 2011 with key words of odontogenic cysts, clinical, radiographic, histopathological, differential diagnosis, treatment and prognosis to collect relevant data. Odontogenic cysts are pathologically significant lesions found in the oral cavity, some of which are common. These cysts are divided into two main types: inflammatory and developmental. Radicular cyst is the most important inflammatory cyst. Also, it is by far the most common odontogenic cyst, which is caused by pulpal and periapical inflammation. The second prevalent cyst is the dentigerous cyst, which is subclassified into inflammatory and developmental. Odontogenic keratocyst is the third most common odontogenic cyst, which is of great importance due to its tendency to recur and its proliferative pathogenicity. Although other odontogenic cysts are not so common, they are introduced because those lesions can be included in differential diagnosis. Sufficient knowledge of dentists about odontogenic cysts results in early diagnosis and treatment plan of these lesions.