Journal of Dentistry, Shiraz University of Medical Sciences
Volume:15 Issue: 4, Dec 2014

Digital radiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digital radiographs.

Statement of the Problem: Bifid mandibular condyle (BMC) is a rare anomaly of uncertain origin which may play a role in some defects in temporomandibular joints. Since it may be misinterpreted as fractures or tumors in condylar area, proper diagnosis will help to prevent unnecessary treatments. A comprehensive knowledge about BMC may help to understand the developmental course of condyle and temporomandibular joints more clearly. The purpose of this study was to estimate the prevalence of bifidity of condyle in a selected population in Iran by employing dental panoramic view. Panoramic views of 1000 individuals (767 female, 233 male individuals) were assessed for bifidity. The patients were over 18 years old and had attended the radiology department of Shiraz dental school from September 2012 to March 2013. A total of 35(3.5%) case of bifidity was detected. Unilateral form was much more prevalent (32 unilateral cases versus 3 bilateral). The left-side bifidity was 3 times more prevalent than the right side. A large number of bifid condyles (63%) have shown symptoms of temporomandibular joint pain or click or both. The prevalence of bifidity in our population was about 3.5%, which was significantly high compared to the other published reports. Symptoms (click and pain) were also much more detected in our study.

Statement of the Problem: Melanin pigmentation of the gingiva is a crucial esthetic problem. A variety of methods have been used for gingival depigmentation. The purpose of this study was to compare the results of two treatment modalities: scalpel technique and cryotherapy with liquid nitrogen in treatment of gingival pigmentation. Twenty patients with chief complaint of gingival pigmentation participated in our study. 10 patients were treated with cryotherapy and remaining 10 participants were undergone the scalpel technique surgery. We evaluated acquiescence and comfort of the patients, degree of depigmentation, based on the area of pigmentation shown by gridlines option in Microsoft Paint software, and the presence or absence of gingival recession before and one month after treatment. Data was analyzed using Mann-Whitney and Chi-Square tests. A significance level of p≤ 0.05 was adopted. Mean value and standard deviation of depigmentation for group A and group B was 96.17±2.51 and 95±2.48, respectively. The difference was not statistically significant (p= 0.225). There was no association between the treatment modality and the gingival recession (p= 0.303) or the treatment modality and the patient satisfaction (p= 0.346). No significant difference was found between gingival recession measures before and after the operation in the two treatment modalities. Surgical blade and cryosurgery with liquid nitrogen had no significant difference in treatment of physiologic gingival pigmentation. Both Techniques are acceptable in the treatment of gingival pigmentation.

Statement of the Problem: Odontogenic cysts and tumors are the most frequent osseous destructive lesions of the jaws; however, there is little information regarding the relative frequency of these lesions among the Iranian population. The purpose of this study was to determine the distribution of clinically and histologically- diagnosed odontogenic cysts and tumors during a period of 13 years in Hamadan, and also its correlation with age, gender, and the site of the lesion. A descriptive cross-sectional study was performed on 413 oral and maxillofacial specimens during 1996 to 2008.The age and the gender of patients, as well as the site of lesion were recorded. The data were analyzed using SPSS software. Totally, 70 specimens were recorded as odontogenic cysts and 11 specimens were diagnosed as odontogenic tumors. The most frequent odontogenic cysts were dentigerous cysts (27.2%), followed by radicular cysts (18.6%) and odontogenic keratocysts (18.6%). In addition, cysts were more frequent in male than female individuals. Ameloblastoma was the most frequent odontogenic tumor (64%). Odontogenic cysts were in correlation with age, gender and location. These results showed that dentigerous cyst and odontogenic keratocyst were more frequent than other studies. More investigations should be performed to determine the frequency of odontogenic tumors in Iran.

Statement of the Problem: Determining the crown-root ratio is crucial in many dental clinical decisions. There are no reliable data presented for Iranian population. The aim of this study was to assess the root-crown ratio of permanent teeth with regards to the relationship of gender and jaw type using panoramic radiographs. The reliability of method was also assessed. The crown and root lengths of teeth were measured by a digital caliper on panoramic radiographs of 185 individuals except for the third molars. A total of 1994 teeth was studied and 50.8% of the teeth belonged to males and 49.2% belonged to females. The modified Lind method was applied. The highest mean root-crown ratios in both arches of both genders were obtained in the second premolars, followed by the first premolars and canines. In both genders, the lowest root-crown ratios were found in the maxillary central incisors. In male patients, the mean root-crown ratio was higher (p= 0.003) than that of females. Using Bland-Altman analysis, a non-significant difference of 0.006 (95% CI: -0.012-0.024) and 0.0002 (95% CI: -0.011-0.011) were found for intra-observer and inter-observer agreement, respectively. Assessment of the root-crown ratio in permanent dentition could be performed on panoramic radiographs with acceptable reproducibility in an Iranian Population. Considering observed differences, our findings suggest that for the accurate assessment, this ratio must be calculated for male and female patients and also for the upper and lower jaws, separately.

Statement of the Problem: The prevalence of overweight and obesity has been increasing markedly in recent years. It may influence growth in pre pubertal children. The purpose of this study was to determine whether increased Body Mass Index (BMI) is associated with accelerated skeletal maturation and dental maturation in six to fifteen years old orthodontic patients in Shiraz, Iran. Skeletal maturation and dental development of 95 orthodontic patients (65 females and 30 males), aged 6 to 15 years, were determined. Dental development was assessed using the Demerjian method and skeletal maturation was evaluated by cervical vertebral method as presented by Bacetti. The BMI was determined for each patient. T-test was applied to compare the mean difference between chronologic and dental age among the study groups. A regression model was used to assess the relationship between BMI percentile, skeletal maturation, and dental development. 18.9% of subjects were overweight and obese. The mean differences between dental age and chronologic age were 0.73±1.3 for underweight and normal weight children and 1.8±1.08 for overweight and obese children. These results highlighted the correlation between accelerated dental maturity and increasing BMI percentile (p= 0.002). A new formula was introduced for this relationship. There was not any significant relationship between BMI percentile and skeletal maturation. Children who were overweight or obese had accelerated dental development whereas they did not have accelerated skeletal maturation significantly after being adjusted for age and gender.

Statement of the Problem: The presence of impacted third molars in the jaws is a common finding in the routine dental examination of patients. Concerning the odontogenic components of the dental follicle, it can be the origin of different types of odontogenic cysts and tumors. The aim of this study was to find feasible radiographic criteria to help differentiate between normal and pathological dental follicles. 134 asymptomatic impacted third molars were recruited in this study. Then, based on the radiographic measurements, the ratio between the diameter of the dental follicle and the mesiodistal width of the tooth crown was calculated. After surgical removal of impacted third molars, the related dental follicles were evaluated histopathologically. Statistical analyses were performed by adopting chi-square test, t-test, receiver oprating characteristic (ROC) curve, and logistic regression using SPSS-19 software. The mean ratio of the dental follicle’s diameter to the mesiodistal width, in the normal and cystic follicle group was 1.18 ± 0.07 and 1.18 ± 0.08, respectively. There was no statistically significant difference between this ratio and the histopathological evaluation. Based on the logistic regression analysis, only the age >20 years and inflammation had predictive value in identifying cystic changes in dental follicle. According to the findings of the current study, the ratio of dental follicle diameter to the mesiodistal width of the teeth cannot not be employed as a diagnostic index to differentiate between normal and pathological dental follicle.

Statement of the Problem: Ameloblastoma is the most common odontogenic tumor which is slow-growing, locally invasive and exhibit specific biologic behavior and high recurrence rate. Likewise, odontogenic keratocyst is a developmental odontogenic cyst that has a high recurrence rate and aggressive behavior. There are limited studies considering the relationship between the angiogenesis factors and the biologic behavior of these lesions. the aim of this study was to evaluate the mean density of vessels in odontogenic keratocysts and ameloblastoma and investigate its possible relationship with biological behavior of these lesions. In this descriptive-analytic cross-sectional study, 40 cases, comprising 10 odontogenic keratocysts and 30 ameloblastomas (10 plexiform, 10 follicular, and 10 unicystic type) were selected and were stained immuno-histochemically with CD34 and CD105. The micro vessel density was assessed and compared in all groups. T- test for the independent samples’ One- way Anova, Wilcoxon test and Tukey tests were adopted for statistical analysis. A statistically significant difference was observed in mean vascular density (MVD) between the odontogenic keratocyst and ameloblastoma groups concerning the CD105 and CD34 markers (p= 0.005, p= 0.000, respectively). The MVD was significantly higher in ameloblastomas than odontogenic keratocyst. MVD with CD34 was significantly higher than MVD with CD105 in ameloblastomas (p= 0.00). It can be suggested that angiogenesis might be one of the mechanisms that is more possible to contribute the aggressive biological behaviors in ameloblastoma rather than odontogenic keratocyst.

Statement of the Problem: Matrix metalloproteinases (MMPs) have been implicated in the pathogenesis of certain diseases and cancers via tissue destruction and can be secreted into the blood stream. MMP9 expression in the salivary gland tissue was evaluated but their serum level in the salivary gland tumors was not studied. The aim of our study was to determine the concentration of serum MMP-9 in healthy participants and in patients with salivary gland tumor. Using an ELISA kit, the circulating levels of MMP-9 in sera from 58 patients with salivary gland tumor (31 pleomorphic adenoma, 17 adenoid cystic carcinoma and 10 mucoepidermoid carcinoma) and 30 healthy controls was assessed. The serum MMP9 level in patients with salivary gland tumors (380.0±301.3 pg/ml) also patients with benign tumors (354.3±218.7 pg/ml) (354.3±218.7 pg/ml) were significantly lower than that in the healthy group (727.4±624.6 pg/ml) (Respectively p= 0.02 and p= 0.01). Mean serum MMP9 concentration in malignant tumors was (402.3±441.8pg/ml) higher than benign tumors (354.3±218.7 pg/ml) but the difference was not significant (p= 0.9). Our results showed that serum level of MMP9 decreased in patients with salivary gland tumors which suggest that MMP9 may not have a potential role in development and pathogenesis of salivary gland tumor.

Maxillary lateral incisors are widely known to be single rooted with one root canal, although rare cases with root canal variations are being reported in many populations, the reports regarding Iranian population is extremely limited. In this report, we are presenting the endodontic treatment of a double rooted maxillary lateral incisor. These rare root-canal variations should be considered in pretreatment evaluations by clinicians who perform endodontic treatments.