مجله تحقیق در علوم دندانپزشکی
سال هشتم شماره 1 (پیاپی 27، بهار 1390)

Periodontium biotype has many variations among different people. It has been suggested that the variation in the periodontium biotype may be related to the shape and form of the crowns of the teeth. The aim of this investigation was to examine the forms of the crowns in the maxillary anterior segment and corresponding gingival characteristics among healthy young Iranian subjects.

For this cross-sectional study 200 individual (100 male & 100 female) with average age of 26.5 ± 7.29 with healthy periodontium were chosen from dental students of Islamic Azad University. The gingival angle, height of interdental papilla, crown width and crown height of maxillary anterior teeth were measured by a digital caliper on a diagnostic stone cast. Also marginal gingiva’s thickness, probing depth and width of keratinized gingival was assessed clinically by a William’s probe on each individual. Binary logistic regression method was used for statistical analysis.

In central teeth (11-21) gingival thickness had a significant correlation with amount of keratinized gingiva and probing depth. In lateral teeth (12-22) gingival thickness had significant correlation with amount of keratinized gingiva, probing depth and crown width. In canine teeth (13-23) gingival thickness had significant correlation with amount of keratinized gingiva, probing depth, crown’s height, papilla’s height and gingival angle. There was no statistical relation between crown’s form and gingival thickness.

Based on the findings, crown form had no relation with the gingival thickness but in each type of tooth gingival thickness was related to different factors.

Periodontitis is a chronic multi factorial infectious disease, characterized by the irreversible destruction of collagen fibers and other matrix constituents of the gingival tissues, periodontal ligament and resorption of alveolar bone around the teeth with the formation of periodontal pocket. During the course of injury, destructions and death of stromal, epithelial or inflammatory cells, different enzymes are released, which can be used as indicators in diagnostic and treatment. The aim of this study was to compare the alkaline phosphase level of saline in patients with Periodontitis and normal ones. In this experimental study, unstimulated saliva of 20 patients with mild periodontitis, 20 patients with moderate to severe periodontitis, and 20 subjects with healthy periodontium were collected. The mean levels of alkaline transferase salivary enzymes were measured by kinetic system. Finally; data were analyzed by ANOVA and TUKEY tests. Mean level of Alkaline phosphatase salivary enzyme in healthy gingival group was 9.25 ± 4.3,in mild periodontitis group was 21.3 ±7.6 and in moderate to severe periodontitis group was 33.75 ±11.9 and there was significant differences between three groups (P<0.05). The results revealed that salivary alkaline transferaze level is a good indicator to determine the degree of periodontal tissue destruction.

Regarding to the importance of anterior permanent teeth in mastication, speaking and esthetic, also high prevalence of crown fracture due to traumatic injuries of the permanent teeth this study was designed to evaluate the etiology and prevalence of crown fracture of anterior permanent teeth in 2nd-5th grade children of primary schools in Rasht in year 2007. For this descriptive, cross-sectional study1042, 2nd - 5th grade students were selected from 10 randomly chosen primary schools in Rasht. Examination was carried out by flash light. Information in regard to age, gender, type of crown fracture, tooth number, amount of over jet, overbite, lip seal, etiology of trauma and performed treatments following trauma were recorded. The data were analyzed with SPSS software and Chi-Square test. Prevalence of crown fracture in anterior teeth was 15.2%. The ratio v male to female patients was 1.7/1. Maxillary central incisors were the most affected (53.5%) and the most common type of crown injury was enamel fracture (80.3%). Most of injuries had occurred at home (49%) and during summer (40.8%). Falls and foreign bodies striking were the most frequent cause of dental traumatic injuries. There was a tendency for children with an increased over jet and deep bite to have more dental injuries.

With regards to the high and increasing prevalence of Multiple Sclerosis (MS) and its demolishing effects on central nervous system and oro-facial nerves appearing oral and maxillofacial manifestations, this study was carried out on the prevalence of oral and maxillofacial manifestations and its related factors in MS patients in 2010. This cross-sectional study was performed on 400 MS patients that were selected by sequential sampling. Oral and maxillofacial manifestations evaluated were as follows: Trigerninal neuralgia, Dysarthria, Dysphagia, (TemporoMandibular Dysfunction) TMD, facial palsy and visual symptoms. Occurrence of each manifestation was determined and its confidence interval was evaluated within a probability of 95% and the role of the related factors was analyzed with the Chi-square test. 89.2% of the samples demonstrated oral and maxillofacial manifestation. The most frequent manifestations were: Visual symptoms 79.5%, Dysarthria 44.3%, Dysphagia 21%, Facial Palsy 15.3%, and TMD 14.3% and the least frequent was Trigeminal neuralgia with 13.3%. The related individual and familial factors showed no relation to the incidence of these manifestations. However compared to the patients with no oral and maxillofacial symptoms, the ones with these symptoms were three times more likely to contract MS with duration of more than seven years. This study revealed a high incidence of oral and maxillofacial manifestations in MS patients therefore it cause for great concern.

Considering the important role of molars in masticatory function and in order to prevent rapid residual ridge resorption in the postextraction phase, it is necessary to replace these teeth in an appropriate way as soon as possible. This study was conducted to evaluate the outcome of immediate tapered wide platform implants instead in molar sockets one year following loading in a private clinic in year 1388- 89. This descriptive study was carried on 12 samples of first and second molars of 10 patients with average of 46±4.71 years, which had referred on year 1387. Immediately after extraction, tapered platform implants were placed. One year following loading, the stability of implants was evaluated by means of periotest. Clinical evaluation was based on: pain, infection and pus drainage. In order to determine crestal bone changes parallel periapical radiographs were taken. Data were analyzed by t- test. none of the samples showed pain, infection, pus drainage or continues radiolucency. The average PTV (perio test value) was-2.81±1.6 with average of -1 to -6 was indicator of no mobility in implants. The average crestal bone change was 0.22±0.01 mm. Installation of tapered wide platform implants at the time of molar extraction maybe successful with ideal case selection and proper surgical procedure.

Squamous cell carcinoma (SCC) is the most frequent malignant tumor of oral cavity and esophagus. Ki67 antigen, a proliferative cell marker, has a significant role in determining biological behavior of the tumors. The purpose of this study was to determine the frequency of Ki67 expression in squamous cell carcinoma of oral cavity and esophagus and their correlated factors. In this descriptive study 40 paraffin embeded blocks of patients with oral and esophagus S.C.C (20 of each) were selected,clinicopathological data were recorded and Immunohistochemical staining(1HC) was done on the newly cut sections for Ki67 antigen. The immunostained cells were counted on 10 HPF(high power fields) percent of positive cells(Labeling Index)was calculated and then cases classified in to low (LI≤48%) and high (LI>48%)levels. Statistical analysis was performed in SPSS,version 13 and Chi-square test. The results showed that 24 cases (60%) were male and 16 cases (40%) were female. The mean age of the patients was 65.3 ± 14.3. 45% of esophageal SCC specimens and 10% of oral SCC specimens were in high expression group. 55% of esophageal SCC and 90% of oral SCC were in low expression group and there was significant differences among oral and esophagus SCC (P<0.05). Age and sex were not correlated with Ki67 expression but the grade and size of the tumors were significantly correlated with the expression of Ki67. (Oral: P=0.01, P=0.03 respectively), (Esophageal: P=0.02, P=0.03 respectively). Ki67 expression in esophageal SCC was significantly higher than oral SCC which may define its more aggressive behavior. Age and sex were not correlated with Ki67 expression, but the grade and size of the tumors were significantly correlated with Ki67 expression.

Aesthetic is a major factor in accepting the removable prosthesis by the patient, and labial aspect of anterior teeth plays an important role in this regard. Therefore evaluating possible determinants of shape of anterior teeth is important. This study evaluated the predictive value of the facial shape determined with three different landmarks settings, in determining central incisor shape. This diagnostic clinical trial was performed on 120 participants. Photographs of the participants were taken in normal head position; images of central incisor of each participant also were taken. Facial outline was determined as oval, triangular, and square, based on three landmarks settings with different upper points: glabella, eye brow, and forehead outline. Teeth labial outline was as well determined as oval, triangular, and square. Diagnostic value of facial shape in determining tooth shape was evaluated. The role of associated factors was evaluated using chi-square test. The positive prediction values of face shapes square, oval, and triangular were 34%, 34.7% and 33.3%, respectively. It seems that the face shape is not an appropriate factor in determining the shape of prosthesis central incisors, and other indicators are necessary to be investigated.

Calcifying odontogenic cyst (COC) is an uncommon developmental odontogenic cyst first described by Gorlin in 1962. It is named cystic calcifying odontogenic tumor in new classification. It is considered as extremely rare and accounts for only 1% of jaw cysts reported. It is unusually seen associated to odontoma. Case Report:The case was A 15 year-old male patient with the chief complaints of painless swelling in the right side of anterior part of his maxilla. Radiographic pattern was radiolucent with radioopacitis foci. In histopathological view, epithelium of odontogenic cyst with ghost cells and complex odontoma were seen. Treatment was done by enucleation,in six mounths follow up there was not any reccurence. Clinical and radiographical features of odontogenic lesions were non-specific. Always we must careful that the type of lesion associated to Gorlin cyst appoints the clinical behavior, method of treatment and prognosis of combined lesion.