Journal of Dental School
Year:2001 | Volume:19 | Issue:3|Papers Count:15

Lingual nerve and Chorda - Tympani are usually damaged during surgical removal of the lower third molar, tooth, removed. The frequency of the damage rated 11 to 22% of all operations. This is mainly due to a lack of knowledge on the position of these nerves in lower third molar region. A group of 430 fresh cadavers have been studied for this anatomical landmark. Results indicated that the distance between upper border of nerve sheath and lingual crest of alveolar process vertical dimension, to be at 3.01±0.42 mm and the distance between lateral border of nerve sheath and middle of lingual plate in lower third molar region horizontal dimension to be at 2.06±1.1mm. The nerve was found to be in contact with lingual plate in 22.3 % of all cases.

Immunocompetent cells and immunoglobulins have been detected in the pulp of erupted teeth and in pulpitis cases. The persistancy of antigenic chalenges are also shown to cause progressive increases in cellular infiltration and immunoglobulin synthesis.The aim of this study was to determine the presence as well the concentration of IgG, IgA and IgM in supernatant fluids of explant cultures of the pulpal samples of impacted and semi-impacted teeth. For this purpose, 16 pulpal samples of impacted teeth were taken from 13 patients with the mean age of 20.2±2.5YTS (56% females and 44% male). Another 16 pulpal samples of semi-impacted teeth were also taken from 16 patients with the mean age of 21.6±3 YTS (63% females and 37% males). Samples were stored in explant tissue cultures for 3 days. SRID method was used in order to determine the presence and concentration of immunoglobulins in supernatant fluids. Results indicated that IgG presence to be at 62.5% of impacted and 18.8% of semi-impacted teeth. The average concentration of IgG in impacted and semi impacted teath was at 833.5±944.5 mg and 81.75±188.7 mg, respectively. IgA presence were detected in 50% and 18.8% of impacted and semi-impacted teeth, respectively, with average concentration of 213.5±257.5 and 50.9±131.5 mg.IgM were detected in 6.3% of cases in both groups. It's concentration was, however, not measurable by the SRID method. Statistical analysis (Fisher exact test, t test, analysis of variance) showed sgnificant difference between impacted and semi-impacted teeth with regard to IgG presence (p<0.015), IgG concentration (p<0.002) and IgA concentration (p<0.01). A significant correlations was found between IgA concentration and maturation status of teeth (p<0.005); as well as IgG concentration with status of tooth impaction (p<0.05).In conclusion: High concentration of IgG and IgA in impacted cases could be due to the higher permeability of blood vessels which leads to extravasation of plasma proteins. The possible cause of higher vascular permability is immaturity of dental pulp in impacted teeth.

Epithelial odontogenic tumors are composed of odontogenic epithelium without participation of odontogenic echtomesenchyme. Ameloblastoma is usually unicentric, non functional, intermittent in growth, anatomically benign and clinically persistent. Ameloblastoma is the most common clinically significant odontogenic tumor. The aim of this study was to investigate age, sex, anatomic distribution, and histopathologic type of the ameloblastoma patients refered to Iranian Dental Schools.An existing data analysis was performed using patient's case notes from oral pathology departments of five dental schools namely Tehran, Shahid Beheshti, Isfahan, Mashhad and Shiraz. Cases were evaluated from those refered to these departments between 1988 to 1998. A check list was provided to record all proposed data which were later analysed. Results indicated that ameloblastoma was in 1% of all patients. The mean age of the whole population of this study was 30.34 years. Male to famale ratio was 1.27/1. Mandible and posterior segment were predominantly affected. Plexiform type lesions were more common, histopathologically Unicystic and conventional type of Ameloblastoma was found to have been presented with a similar frequency.

The purpose of this study was to determine the best cut-off point for a linear measurment (A-B difference) projected on True horizontal and Frankfort horizontal plane as a sagital jaw indicatore. In addition, it was to determine the accuracy of this method as well as examining the validity of the test among different facial types. A total of 205 pretreatment lateral cephalograms were selected from those being taken in natural head position (NHP) with no history of orthognatic surgery and craniofacial syndrorns. A combination of 5 measurment was used as gold standard for a comparison to the cut-off points. Results showed that cut-off point of more than 6.5mm (PPV: 75%, NPV: 77%) diasnosed as Cl II malocclusion and those over7mm (PPV: 78%, NPV: 77.5%) for PH and True horizontal reference planes. Those cases with cut off point more than 1mm (PPV: 100%, NPY 88%) diagnosed as Cl III malocclusion, while those over 0mm (PPV: 95%, NPV: 88%) for PH and TH reference planes. Conclusion: The accuracy of this method at best was not more than 88% and most of false negative and false positive cases were those with high angle or - low angle cases.

The rate of dental caries is reported to be as moderate in 12 year old Iranian children. This is according to the WHO report (EMRO branch). This article is based on an overall assessment of a broad based study on 6 to 12 year old Iranian primary school children, for their DMFT score.A total of 6200 Iranian children aged 6-12 years, were evaluated by a clinical examination using WHO criterias.Results showed that the mean DMFT score of 6, 9 and 12 year old children were at 0.2., 0.9±0.05 nd 1.5±0.01 respectively. Caries rate was about 5 times more in 9 year old children compared to those in 6 years of age and 1.5 times more in 12 year old patients compare to those with 9 years of age. Only 12 percent of the teeth were reported to be filled. Conclusion:There was a clear difference between caries rate of the different sexes. It was also noted that the prevalence of dental caries was higher in mandibular teeth than maxillary ones.

Tooth loss causes deficiency in the normal function of masticator muscles. Complete denture improves the function. However it is shown that masticatory efficiency is less in denture wearers compared to dentate subjects.The purpose of this study was to compare the electromyographic activities of masticator muscles between dentate subjects and denture wearers in order to assess the problem.A group of 10 dentate individuals were selected in association to a group of 10 edentulous patients. Complete dentures were constructed for edentulous patients. Electromyographic activities of right masseter and temporal muscles were recorded in maximum voluntary clenching, ipsilateral and contra lateral chewing, swallowing and phonetic three months after the prosthetic insertion. Paired-t test was used to show the differences with results indicating that integrated electromyographic activities of both muscles to be greater in dentate subjects than denture wearers during maximum voluntary clenching and ipsilateral chewing (P<0.05).However, no significant difference was found in swallowing, between the results achieved from the two groups lested.

Despite the significant life saving effects of chemotherapeutic drugs in patients with blood malignancies, there has been a high rate of side effects on oral mucosa reported in the literature. A randomized controlled double-blind clinical trial in 1995 was designed to evaluate the preventative effects of a 002% Chlorhexidine Gluconate on oral complication.A group of 45 diagnosed acute leukemic patients (69% male and 31% female, mean age 25.9±905) were selected for this study who were reffered to three major hospitals in Tehran, namely: Imam Khomeini, Shariati and Modarres General Hospitals. None of the subjects used any mechanical too for oral hygiene. Patients were clinically assessed prior to the chemotherapy and at 1, 2, 3, 4 weeks post therapy, by their plaque index, gingival index, mucosa status, and colour of the teeth. A swab sample was taken from oral mucosa for paraclinical evaluation. Subjects were divided into experimental and control groups, randomly the experimental group received Chlorhexidine Gluconate 0.02% oral rinse and the control group were given a placebo.Results revealed that the experimental group showing a significant reduction in plaque index, gingival index and mucositis (P<0.025). Only dental colour index was increased. Paraclinical indices including total bacterial count, Staphilococci SP, Streptococci SP and Candida colony count were decreased in experimental group (P<0.0.1).In conclusion: Chlorhexidine showed to be effective in reducing oral complications of chemotherapy.

This study was performed to compare the clinical effect of Citric Acid and Doxycycline root conditioning in order to improve the coverage out come of laterally positioning graft (L.P.G) in denuded roots.The effect of L.P.G. with and without the Citric Acid has previously been investignted. The present study was looking at the effect of Doxycycline incorporated in the procedure as a root conditioner.A total of 28 denuded roots, 17 cases with Doxycycline and 11 cases with Citrci Acid, have been root conditioned followed by an immediate laterally positioning graft to cover the denuded area. Results indicated that:1.Non of these materials have significant dominancy on the other one in improving root coverage.2. The mean root coverage level was 0.85 mm in Citric Acid treated cases and 1.32mmin Doxycycline treated ones, both of which were significant.3. The coverage gained was not found to be dependent on the root conditioning material and the operation itself is mainly believed to improve root coverage.4. The procedure also resulted in pocket depth reduction.

The purpose of this in vitro study was to invtestigate the microleakage of a composite following the use of Carbamide Peroxide. A total of 80 Sound permolar teeth were selected, with class V cavity preparation, filled with Tetric Flow or Syntac. Specimens were divided into four groups after being subjected to 500 times of thermal cycling. Group A (Control) was kept in humidor for 3 weeks, while groups B, C and D were kept in contact with lOck Carbamide Peroxide using a special appliance for 2, 3 and 4 weeks (time of immersion in bleaching agent was 8 hours in each day). The roots and crowns were primarily sealed using a nail varnish. Each tooth was then immersed in 0.5% Basic Fuchsion. Pollowed by sectionning from about 2 mm below the CEl. Dye penetrations were measured by stereomicroscope in gingival and occlusal margins. Pearson"s test and log linear with 95% significancy were employed to evaluate the data. Results showed:1- No relation be~een the type of margin and dye penetration in group A, Band C. However the frequency was greater in group Band C compare to the group A.2-There was a correlation between type of margin and dye penetration in group D,.3-The highest dye penetration was seen in group D at the gingival margin.4-The highest dye penetration was seen in groups Band D at their occlusal margins, respectively.Inconclusion: Microleakage is seen in restorations after two weeks immersion in Carbamide Peroxide, this means that any restoration should be replaced if subjected to the bleaching procedure.

Thalassemia syndrome is part of a larger group of inherited hematologic disorders known as hemoglobinopathies. Skeletal changes resulting from this disease are striking and facial bones are effected by this disease primarily. Orthodontic treatment are carried out to over come dentofacial deformities. However this method is not always successful and therefore orthognathic surgical management of the patient with thalassemia could be required. A Case of thalassemia major who had received this treatment is presented in this report.

The aim of this investigation was to evaluate the prevalence of dental caries Amongst a group of institationized mentally handicapped children" aged 6 to 12 years. A total of 302 children 173 boys and 129 girls. were encluded for this study who were institutionalized under the city council and Tehran shealth board. candidates were selected in a simple random sampling manager. Results revealed that the mean DMFT of the population of study was at 1.81 for permanent teeth and 1.77 for primary teeth. The mean DMFT of the edlest age group of this population (12 year olds) was 2.76,dearly higher than the mean DMFT of youngest and the whole the rate of the dental caries was found to be higher amongst these handicaps children (65.64%,) when compared to the same age group in normal population.Implementation of a reasonable training program for promoting general knowledge of service providers in relation to oral and dental care including various preventive measures are highly recommended.

Schowannoma is a benign neural neoplasm of schwann cell origin. It is relatively uncommon, 25 to 48 percent of all cases occur in the head and neck. The most common location for oral neurilemomas are tongue, palate, floor of the mouth, buccal mucosa, gingiva, lip, vestibule and jows. Although the occurance of this tumor is rare, in floor of the mouth it is estimated that, this location is the third most common side of the oral cavity for this" involvement. It is an encapsulated sub mucosal mass which presents typically as an asymptomatic lump in patients of any age with a peak prevalence at the second and third decades of life. The present case was a 10 year old boy who was referred by his dentist for diagnosis atreatment of a mass in floor of his mouth with 3 month history.Details of clinical and histopathologic features of this case showed that the lesion was a classic schwannoma.Treatment of such cases are usually done by an excisional biopsy, as was performed here and the patient show also no recurrence after a year of treatment.

The method of selection of the study design decides the type of analysis 10 be used. Case-Control studies assess the causes of a particular outcome, comparing a group of individuals who have experienced the outcome under study with a group who have net.Results appear as a two by two table. As these two groups are sampled separately, the rate of the disease in the exposed or unexposed groups can not be calculated. However, the Odds Ratio can be obtained. The Odds Ratio is sometimes referred to as the cross product ratio.                        Cases                            Controls Exposed            a                                  b Unexposed         c                                  d Odds Ratio (a/b)I (c/d) = ad/bc