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Background and Objective: Impacted molars teeth, especially third molar, are important in most branches of medical sciences. The angular position of molar teeth is in side effects and therapeutic regiment. This study was conducted to determine the angle of the impacted mandibular third molars. Materials and Methods: This descriptive study was carried out on 429 patients (269 men and 160 women) selected for surgery on impacted mandibular third molar in the oral and maxillofacial surgery clinic in Gorgan, Iran during 2010-11. Pre-operative diagnosis was done by physical examination and OPG radiography. Demographic characterstics including age, gender, ethnicity, impaction angle were recorded for each subject. Data were analyzed using SPSS-16, independent t-test and chi-square test. Results: Totally, 480 impacted third molars were studied. Mean age of patients was 26.06±6.21 years. Impaction of the third molar was more prevalent among men (62.7%) than women (38.30%). Impacted mandibular third molar of 189 people (44.1%) were in left side in 200 people (46.6%) were in right side and in 40 people (9.3%) were bilateral. According to impaction angle, mesioangular (41.7%) and distoangular (3.5%) types had the highest and the lowest frequency, respectively. In bilateral cases, the mesioangular-mesioangular type (48.8%) was the most prevalent. The mesioangular type was the most prevalent in all ethnic groups. The most prevalent angular position of the impacted third molar was the mesioangular type in both sexes. Conclusion: This study showed that the most prevalent angular position of impacted mandibular third molar is the mesioangular type.

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Background and Objective: Many surgeries are performed on anterior region of mandible. Incisive branch of the inferior alveolar nerve is located in the anterior region of mandible. The identification of various form of nerve is important for diagnosis and treatment plan. This study was carried out to the assessment of visibility and extension rate of incisive branch of the inferior alveolar nerve in cone beam computed tomography (CBCT) imagings. Methods: This descriptive – analytic study was performed on 105 CBCT images. The presences or absence of incisive branch of the inferior alveolar nerve and assessment of visibility and extension rate of mandibular incisive canal were studied. Results: In 79% extension of the incisive branch of the inferior alveolar nerve were observed. 18.07% of extensions were observed in one-side and 78.31% were bilateral. Extension of the incisive branch of the inferior alveolar nerve was observed to central, lateral and canine tooth in 59%, 26.5% and 14.5% respectively. There was no significant relation beween gender and age of subjects with extension of the incisive branch of the inferior alveolar nerve. Conclusion: Regarding the high visibility of the incisive nerve branches in the lower dental CBCT images this method can be used to evaluate the anterior region of mandible.

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Background and Objective: Permanent first molars are susceptible to caries due to their particular anatomical form, early development and lack of knowledge of parents about their permanence. This study was conducted to determine the index of first permanent dental careis (DMF6) and some of its related factors in 12 year-old students.
Methods: This descriptive-analytical study was carried out on 400 students (200 females and 200 males) using combined method (stratified and cluster sampling) from public and non-governmental schools in Gorgan, northern Iran during 2015-16. First permanent molar examination was carried out. The parents' education level, frequency of toothbrushing and daily consumption of sugar-containing snack foods was recorded in a questionnaire. Each decayed, missing and filled first permanent molar tooth was given number one. These numbers were combined to compute the DMF6 index for each individual.
Results: The DMF6 index was zero in 19.5% and the DMF6 index was determined to be between
1 and 4 in 80.5% of the children. The mean DMF6 index was 2.23±0.07 and significantly higher in girls (2.39±0.10) than in boys (2.07±0.11) (P<0.05). The DMF6 index decreased with increasing parental education and the frequency of brushing and reducing consumption of sugary meals.
Conclusion: Dental caries prevalence among 12-years-old students in north of Iran is higher (2.23) than global standard until 2020 (lower than 1). Gender of child, parent’s education, frequency of toothbrushing and consumption of sugar-containing snack foods plays an important role in the rate of dental caries.

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Background and Objective: Avulsion of permanent teeth is a common emergency condition in pediatric dentistry. The prognosis of avulsed teeth depends on the appropriate and efficient approach of unprofessional persons such as the parents and school teachers who are present at the incident site, prior to the professional dental visit. This study was done to evaluate the parental knowledge regarding emergency management of traumatic tooth avulsion in north of Iran.

Methods: This descriptive-analytic study was performed on 264 parents (76.8% mothers and 23.2% fathers) of children aged 6 to 12 years old whom referred to Ayatollah Taleghani Hospital in Gonbad-e-Kavoos a twon in Golestan Provinece, northern Iran during 2015-16. The subjects were interviewed using a questionnaire form with 11 objective questions. The questionnaire included personal information and parental knowledge about traumatic tooth avulsion.

Results: 84.8% of parents had insufficient knowledge. The father`s and mother`s knowledge rate was 13.3% and 16%, respectively. There was no significant association between educational levels, age or gender and knowledge rate.80.8% of subjects did not received education about how to react after traumatic tooth avulsion.

Conclusion: Parental knowledge regarding emergency management of traumatic tooth avulsion is very low. Considering the irreversible consequences of this injury in delayed management, increasing parental knowledge is necessary.

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Background and Objective: Gingival recession is a common disease leads to esthetic problems, increased sensitivity of teeth and root caries. This study was done to determine the prevalence of gingival recession in dental students with high level of oral hygiene.
Methods: This descriptive-analytic study was performed on 214 dental students of Golestan University of Medical Sciences, Gorgan, Iran during 2017-2018. After collecting demographic information, clinical examination including Oral Hygiene Index (OHI) and Gingival Index (GI), Severity of gingival recession, width of keratinized gingival, attachment of frenulum, toothbrush trauma, tooth malpositions, periodontal diseases and other iatrogenic factors was measured.
Results: Prevalence of gingival recession was 23.8% .Class 1 and 2 of gingival recession was 84.62 % and 15.38%, respectively. Class 3 and 4 of gingival recession did not observe in any subjects. Toothbrush trauma was the most etiologic factor in 35.4% of dental students suffering of gingival recession (P<0.05). Also, dental malposition with 20.83%, loss of keratinized gingival with 14.58%, orthodontics procedures with 12.5%, periodontal diseases with 10.4% were the other factors in gingival recession.
Conclusion: Toothbrush trauma and dental malposition are the most important etiologic factors in dentistry students suffering from gingival recession.

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Background and Objective: One of the health indices in human is normality of the number and size of blood cells. The purpose of this study was to screen for bleeding and coagulation disorders among the patients in oral medicine department of Yazd dental school.
Methods: This descriptive - analytic study was performed on 273 patients referred to the oral medicine department of dental school in Yazd, Iran during 2015-16. Data of age, sex, systemic diseases and their type, medical history, patient’s clinical examinations and also the cause and type of requested laboratory tests were recorded for each sujects.
Results: Bleeding and coagulation lab tests were ordered for 63 persons (23.4%) and complete blood count (CBC) for 210 persons (76.9%). The CBC of most patients with systemic diseases (53 cases, 25.2%) was normal. The most frequent systemic disorders were cardiovascular diseases (56%) and followed by bleeding disorders (19%). The most frequent abnormality of CBC components was seen in the distribution of neutrophils (84.9%). There was no significant correlation between CBC results and its components and also PT, BT and PTT with the age of the patients. Platelet counts, Hb and INR results showed a significant correlation with the age of the patients (in age range of 6-83 years) (P<0.05). Platelet counts, WBC, PT, lymphocyte, neutrophil and RBC, Hb, MCV and MCH results were significantly different between females than males (P<0.05).
Conclusion: The majority of bleeding and coagulation labratory test results of patients were normal, which can indicate the readiness of the patients to tolerate dental treatments. The results of this study help to reduce the unnecessary laboratory test orders and patient costs with a thorough medical history and careful consideration of clinical findings.

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Background and Objective: Maxillary sinus gradually extends laterally and inferiorly during pneumatization, and lamina dura of molar and premolar teeth can make a part of sinus floor. Knowledge about this anatomic relationship is essential to prevent complications paticularly iatrogenic perforation of sinus floor. Limitations of periapical and panoramic radiographs to visualization of this relationship led to the usage of cone-beam computed tomography (CBCT). This study was aimed to evaluate the vertical and horizontal relationship between roots of maxillary molars and sinus floor in CBCT images.
Methods: In this descriptive cross sectional study, ninety-five samples were selected of patients in Department of oral and maxillofacial radiology in Tabriz, Iran using simple randomization. Mean age of patients was 32.5 years old. Images were made by VGi cone beam Newtom and reconstructed by NNT viewer version 2.17. The vertical and horizontal relationship between roots of 139 maxillary first and 126 second molar teeth and floor of sinus evaluated.
Results: Type 2 was the most common relationship among the first and second molars, vertically (the inferior wall of the sinus located below the level connecting the buccal and palatal root apices,without an apical protrusion) and horizontally (the alveolar recess of the inferior wall of the sinus located between the buccal and palatal roots). There was a significant relationship between the type of tooth and sinus floor (P<0.05).
Conclusion: Most of the maxillary molar roots were in contact with sinus floor and sinus floor was extended mostly between buccal and palatal roots vertically and horizontally, respectively. Attention to sinus involvement possibility during interventions in maxillary molar region is important.

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Background and Objective: Periodontal disease has high prevalence in diabetic patients and the knowledge of them about the relationship between diabetes and periodontal disease is effective in the control of the blood glucose and progression of periodontitis. This study was done to evaluate the knowledge, attitude and practice of diabetic patients about periodontal disease in Gorgan north of Iran.
Methods: This descriptive-analytical study was done on 300 type 1 and 2 diabetic patients (136 males & 164 females) whom referred to governmental health centers in Gorgan, northern Iran during 2019. Demographic information, knowledge, attitude and practice were recorded using a questionnaire.
Results: The level of good knowledge, attitude and practice were evaluated 51.7%, 44.3% and 25%, respectively. There was significant association between oral hygiene practice and gender and education (P<0.05). Good practice was observered more in females and in patients.
Conclusion: More than half of diabetic patients had moderate to good knowledge and attitude about periodontal disease but their practice was moderate to poor.