مجله دانشکده دندان پزشکی اصفهان
سال هشتم شماره 7 (پیاپی 35، زمستان 1391)

Glass-ionomer cements (GICs) are one of the most important restorative materials in dentistry. Similarly, hydroxyapatite (HA) is of the most well known bioceramics. The aim of this study was to prepare a type of glass-ionomer cement with nano-particles of hydroxyapatite to improve GIC bioactivity and compressive strength. Natural HA particles were extracted from animal bone. The ceramic component of GIC was produced by melting and characterized. HA particles were incorporated into the cement component of GI at 1, 3, 5 and 7 weight percentages. Bioactivity and compressive strength of GIC\HA composite were evaluated in a simulated body fluid (SBF). One-way ANOVA was used for data analysis (n = 3). The results of characterization tests confirmed the production of GIC using the melting technique. Amorphous and glassy structure of GIC powder and its proper chemical composition were verified by characterization tests. The results of soaking test in SBF showed increased bioactivity of GIC/HA composite. Finally, the results of compressive tests showed that incorporating HA up to 5 wt% would not decrease the compressive strength of GIC. GIC/HA nano-composite with 5 wt% of HA was the most appropriate sample regarding its bioactivity and mechanical properties for dental applications. Introducing this novel nano-composite can play an important role in improving the properties of glass-ionomer cements.

The aim of this in vitro study was to compare the efficacy of 17% EDTA, 5% maleic acid and 6% phosphoric acid in removing the smear layer using scanning electron microcopy. In this in vitro study, eighty human single-rooted teeth were selected and divided into three experimental groups (n = 25) for the application of 17% EDTA, 5% maleic acid and 6% phosphoric acid in order to remove the smear layer and one negative control group (n = 5). The canals of all the teeth were prepared using the step-back technique up to #40 in the apical area and up to #80 in the coronal area. Then final irrigation was carried out using 5 mL of one of the experimental solutions with a 30-gauge needle for 1 minute in each group. The teeth were then cut longitudinally and split into two halves by wedging action and the canal surfaces were viewed under SEM in the coronal, middle and apical areas. The photomicrographs were scored by two observers according to the extent of the smear layer removal. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests to compare the groups and Friedman and Wilcoxson tests to compare different areas (α = 0.05). No significant differences were observed between the three solutions (p value = 0.642). The cleanest area was the coronal followed by the middle and apical areas (p value = 0.001). All the three solutions were similarly effective in removing the smear layer from the root canal walls.

Oral lichen planus is a chronic immunologic mucocutaneous disorder with an unknown etiology. This condition has various types. Erosive and bullous types of this disorder are painful and need to be treated. Several etiologies, such as immune cell disorders, stress and deficiencies of some vitamins have been suggested for this disorder. The aim of this study was to compare vitamin B12 serum levels in lichen planus patients and healthy subjects. In this case-control study, 20 healthy subjects and 32 subjects with lichen planus were selected as the control and case groups, respectively. The mean vitamin B12 serum levels were determined in both groups. Finally, data were analyzed by t-test and Chi-squared test using SPSS statistical software (α = 0.05). The mean vitamin B12 serum levels in the case and control groups were 328.87 ± 103 and 365.35 ± 83 pg/mL, with no significant differences between the two groups (p value = 0.12). Under the limitations of this study, no relationship was observed between vitamin B12 deficiency and lichen planus.

The most common reasons for dental traumas during childhood and adolescence are falling, accidents and sporting events. The most frequently traumatized teeth are anterior teeth, leading to eating problems and unpleasant psychological effects. The aim of this study was to assess frequency of dental injuries, cause of these injuries and treatments rendered based on Iran Insurance Company files. In this descriptive/analytical study 400 files related to dental traumas of 7-12-year-old children were randomly selected from children injury files in Isfahan in 2010-2011, and the demographic data along with data on the traumatized teeth, etiology of trauma and the treatment rendered by the dentist were collected. Data were analyzed by SPSS 16 using descriptive statistical tests. Frequency of dental injuries in governmental schools (75%) was higher than that in non-profit schools (25%) and higher in boys compared to girls. In addition, more injuries were found in the 10-12 age group in comparison with the 7-9 age group. The most frequently traumatized teeth were maxillary right central incisors and the most common etiology of trauma was sporting accidents. In 91.3% of cases, the tooth crown was fractured and in 14.2% of cases the root was fractured, with or without crown fractures. Filling (81.1%) was the most common treatment received and 17.4% of traumatized teeth had been extracted; 87.3% of injuries had been treated by general dentists and the remainder by specialists. Based on the results, gender and age were predisposing factors for dental trauma. The most frequently traumatized teeth were maxillary central incisors and the most frequent injury was crown fracture and filling was the most frequent treatment received.

Panoramic images can be obtained using film-based conventional techniques and digital imaging systems. Compared with conventional film-based techniques, digital panoramic imaging systems have some advantages such as dose reduction, image manipulation, saving time and elimination of the need for toxic processing chemicals. The aim of this study was to investigate the diagnostic accuracy of filtered digital panoramic radiographs for assessment of interproximal caries in comparison to bitewing radiography. In this descriptive/analytical study 608 interproximal surfaces, from the mesial surface of the first premolar to the distal surface of the second molar, were evaluated on filtered digital panoramic radiographs and conventional bitewing radiographs for interproximal caries by two oral and maxillofacial radiologists. Data were analyzed by SPSS 11.5 using kappa and Wilcoxon statistical analyses and calculation of reliability coefficient and Spearman’s correlation coefficient at 95% significance level. There were statistically significant differences in frequency distribution of caries between the two techniques (p value = 0.002) and also between frequency distribution of diagnostic agreement between these two techniques (p value < 0.001(. According to the results of this study, the diagnostic accuracy of filtered digital panoramic radiography is significantly lower than that of conventional bitewing radiography for detection of interproximal caries.

Despite advances in different fields of the dental science, dental caries is still one of the most common infectious diseases worldwide, which is an insurmountable problem in the health care system of many countries. DMFT index is one of the best methods to assess oral hygiene status and is influenced by educational and socio-economic factors. The aim of this study was to evaluate DMFT index among dental, medical, engineering and Islamic science students in Hamadan, Iran. In this cross-sectional/descriptive study, 200 students were selected from four different fields (n = 50 in each field) using simple random sampling technique. Clinical examinations were carried out by a senior dental student under dental unit headlight using dental mirrors and explorers. Data were analyzed with ANOVA and a post hoc Tukey test by using SPSS 15 (α = 0.05). The mean DMFT was 7.89 ± 3.48. DMFT index differences were minimal between the four groups and the dental students had the highest index (8.8 ± 4.30), followed by Islamic science students (8.48±3.32), engineering students (7.94 ± 3.43) and medical students (6.72 ± 4). When each index was compared within each group, there were statistically significant differences for each individual index. Under the limitations of this study, although DMFT score was higher in dental students, caries was lower among dental and medical students. New educational programs seem to be necessary for oral health improvement in the student community.

Mother's milk is very suitable for the nourishment of infants. Despite the capability of breast glands to refine and purify, some poisonous metals, such as mercury, might seep into the mother's milk. The aim of this study was to determine the relationship between the number of tooth surfaces restored with amalgam and the amount of mercury in mother's milk because mercury is one of the constituents of dental amalgam. In this preliminary descriptive study the subjects consisted of breast-feeding mothers referring to a health center in Isfahan. A total of 25 systemically healthy mothers, aged 18-35, who had given birth less than two months previously, were selected. Simultaneously, 5 mothers with no amalgam restorations were selected as the control group. At first the number of tooth surfaces restored with amalgam was recorded. Then approximately 6 mL of milk were taken from each mother. The mercury levels of the milk samples were measured by cold vapor atomic absorption spectrophotometric method. Data were analyzed by SPSS using independent t-test and correlation coefficient. The average number of amalgam surfaces restored in 25 samples in the test group was 14.56. The mean of milk mercury level was 1.5748. There was a significant relationship between mercury levels of mothers’ milk and the number of amalgam restoration surfaces (p value < 0.001). Under the limitations of this study there was a significant relationship between mercury levels of mothers’ milk and the number of amalgam restoration surfaces.

Dentists are exposed to mercury vapor from dental amalgam in their routine occupational practice; excess exposure to mercury is harmful. The aim of this study was to assess the influence of some possible related factors on the urine mercury levels of general dentists and restorative specialists in Mashhad in 2010. This cross-sectional study was performed randomly on 45 general dentists and 10 restorative specialists in all the regions of Mashhad. A sample of the subjects’ urine was taken before routine daily occupational practice and they were provided with a questionnaire about their working conditions and demographics. The levels of urinary mercury were analyzed by atomic absorption spectrophotometry using 485-nm wavelength. Data were analyzed by ANOVA, Pearson’s correlation coefficient and linear multiple regression (α =0.05). The mean urine mercury levels for general dentists and restorative specialists were 9.26 ± 2.70 and 9.13 ± 1.79 µg/L, respectively. There were no significant relationships between urine mercury levels and working hours per day, type of amalgam used, number of amalgam restorations per week and different regions. However, there was significant relationship between type of office ventilation and urine mercury level (p value = 0.001) and amalgam waste disposal technique and urine mercury level (p value = 0.000). The level of urinary mercury in general dentists and restorative specialists did not exceed toxic levels. There was a significant relationship between the urine mercury level and type of office ventilation and the method of amalgam waste disposal.

The aim of this study was to evaluate the effect of oral and dental health on the family’s quality of life and it’s relation with DMFT, dmft, malocclusion and presence or absence of trauma in students. In this descriptive cross-sectional study, 210 physically and emotionally healthy students, aged 9-11, were selected from primary schools of Amol, Iran, using simple random sampling technique. FIS (Family Impact Scale) questionnaire was completed by each student. DMFT and dmft indexes, malocclusion (based on Angle’s classification) and presence or absence of trauma were recorded and analyzed by SPSS 11.5, using ANOVA and Spearman’s correlation coefficient at a significance level of 95%. The dmft index had a significant relationship with the overall FIS questionnaire score (p value < 0.03). There were no significant relationships between economic condition (p value = 0.2), birth rank (p value = 0.1), DMFT (p value = 0.1), age (p value = 0.9), and the number of children in the family (p value = 0.7) and the total score of FIS questionnaire. Spearman’s correlation coefficient showed a significant correlation between age and dmft (p value < 0.001). Under the limitations of the present study, decay of deciduous teeth had a significant effect on quality of life of families. However, there were no significant relationships between malocclusion and trauma and family’s quality of life.

Close proximity between third molars and inferior alveolar canal is common. It is important to prevent damage to the inferior alveolar nerve during surgery. This research was undertaken to show the efficacy of panoramic radiography technique in demonstrating the relationship between impacted third molars and inferior alveolar canal by using a surgical technique. Sixty patients, referring to Isfahan Faculty of Dentistry and the relevant clinic during 2011-2012 educational year, were selected for this descriptive/analytical study by a radiologist; the subjects had at least one sign about the close proximity between the inferior alveolar canal and the tooth on their panoramic radiographs. The third molars were surgically extracted by a maxillofacial surgeon and the existence or non-existence of close proximity between the tooth and the canal was recorded as a gold standard. McNemar’s test was used to evaluate the diagnostic power of the radiographic technique (α = 0.05). The positive predictive value for superimposition of tooth image on the upper rim of the canal (p value = 0.1), superimposition of the tooth image on the entire canal (p value < 0.001) and superimposition of the tooth image on the entire canal along with narrowing of the alveolar canal (p value = 0.013) had higher diagnostic values compared to other signs, with positive predictive values 59.3%, 86.3% and 54.5%, respectively. Under the limitations of this study, it can be concluded that superimposition of tooth images on the entire alveolar nerve canal with narrowing and deviation of the canal can indicate a real relationship between the tooth and the canal.

Infection control is an important part of dental treatments. One of the infection transmission pathways is through dental impressions. Instructing dentists in infection control and effective educational programs decrease the odds of infection transmission. The aim of this study was to evaluate the knowledge and attitudes of dentists about disinfection of dental impressions. In this descriptive study 93 general dentists were randomly selected in Ahvaz in 2010. To collect data, a questionnaire which included demographic data and 15 questions about knowledge and 14 questions about attitude was prepared. The questions on knowledge and attitude were scored and each correct question on knowledge received one positive score. In addition, questions on attitude were scored between 1 and 5. Finally, data were analyzed by t-test and chi-squared test (α = 0. 05). The mean and standard deviation of general knowledge of dentists was 6. 1 ± 0. 2; 66 subjects (٪70. 96) had poor knowledge, with the mean and standard deviation of 4. 65 ± 0. 1; 21 subjects (٪22. 58) had medium level of knowledge, with the mean and standard deviation of 9. 3 ± 0. 2; and only 6 subjects (٪6. 45) had a good knowledge level, with the mean and standard deviation of 12. 3 ± 0. 2. The overall mean and standard deviation of attitude of dentists was 63 ± 8; 86 subjects (٪92. 5) had medium attitude, with the mean and standard deviation of 61 ± 6; and 7 subjects (٪7. 5) had good attitude, with the mean and standard deviation of 85 ± 5. The results of this study showed that the majority of dentists in Ahwaz have good attitude toward disinfection and the related equipment but they have poor knowledge about the use of disinfecting agents, necessitating continuous educational programs in this respect.

In most countries tourism is the main source of income, employment and development of private sector and infrastructure. Nowadays health and dental tourism is the most rapidly growing sections of the world tourism industry. This study aimed to investigate dental tourism and to determine social, cultural and infrastructural factors affecting development of this industry in Isfahan, Iran.

This descriptive/analytical study was carried out using a questionnaire which included demographic data, characteristics of foreign tourist's seeking dental and medical services, political, social and cultural factors, the existing infrastructures, costs and questions on ways to develop dental tourism. The questionnaires were given randomly to 62 dentists in Isfahan. Data was analyzed by SPSS 19, using descriptive statistical analyses and t-test.

The results showed that the main factors affecting the development of dental tourism, with the highest mean scores, respectively, were as follows: a center to provide a variety of dental services (4.81 ± 0.398), reasponable costs of dental services (4.56 ± 0.315), continuous and appropriate publicity, development of infrastructures for the welfare of tourists (4.14 ± 0.243), and cultural, social and political factors (4.02 ± 0.324). T-test did not reveal any significant differences between gender and mean scores of infrastructures (p value = 0.184), cultural, social and political factors (p value = 0.384) and tarriffs (p value = 0.774).

The results showed the importance of political, social and cultural conditions and costs in increasing the possibility of rendering dental services and increasing the number of dental tourists. Since Isfahan has a lot of ecotourism attractions and competitive advantages of expenses, ideal infrastructures and quality of services, it has considerable potential for health tourism. Use of proper publicity in hotels and airports might be a suitable strategy to develop dental tourism industry.

Amelogenesis imperfecta (AI) is an inherited disorder which alters enamel structure. The primary clinical problems of these patients include poor esthetic, tooth hypersensitivity and loss of occlusal vertical dimension due to rapid wearing of dentition. The aim of this study was to review AI and various treatment plans used for these patients.

This review study was carried out by running a search in library sources and Pubmed, ISI Web of Science and ISC websites from 1975 to 2011, using amelogenesis imperfecta, enamel defects and treatment as the key words.

The inheritance pattern and prevalence of AI varies among populations and in addition to enamel defects, other dental and skeletal manifestations may also be present in these patients. Different treatment options have been proposed for these patients, including microabrasion, gold or stainless steel crowns, all-ceramic and metal-ceramic crowns, porcelain laminate veneers, onlays and composite resin restorations.

In some severe cases, designing an optimum treatment plan in AI patients can be challenging and an interdisciplinary approach is usually necessary to evaluate diagnosis and treatment problems of patients, using a combination of periodontal, orthodontic, orthognathic surgery and restorative treatments.

Peripheral giant cell granuloma or giant cell epulis is a relatively common reactive lesion of the oral mucosa in response to local irritation and trauma. It is mostly seen in women during the 4th to 6th decades of life. Since recurrence is relatively common surgery with extraction of the involved tooth or teeth and curettage of the alveolar bony socket is the preferable treatment. In children this lesion can occur after deciduous tooth root resorption and might have a more aggressive clinical course in this age group. Case report: Reported here is occurrence of a relatively common lesion in an uncommon age and sex group. A soft tissue lump in an asymptomatic, otherwise healthy, 10-year-old boy with no evidence of bone destruction was surgically excised and submitted for microscopic evaluation. Microscopically a diagnosis of peripheral giant cell granuloma was established. At 6-month follow-up the site of surgery had healed completely with no post-surgical complications. Discussion and Although peripheral giant cell granuloma is more common during the 4th to 6th decades of life, this lesion might occur in children, with alveolar bone resorption, abnormal patterns of eruption of permanent teeth and loose and displaced teeth. Therefore, the aim of this report was to draw attention to the possibility of the occurrence of these lesions at a young age to pave the way for early diagnosis and treatment.