مجله دانشکده دندان پزشکی اصفهان
سال هشتم شماره 2 (پیاپی 30، خرداد 1391)

Third molars have the greatest incidence of impaction. There is no general agreement on the removal of asymptomatic impacted third molars. EGFR might be an indicator of increased potential for tumoral and cystic changes. The aim of this study was to investigate the expression of EGFR marker in the follicles of impacted wisdom teeth and its relation to radiologic features.

In this cross-sectional/analytical research, 40 samples of wisdom tooth follicles, embedded in paraffin blocks, were studied. After preparing the specimens and primary observation of H&E slides, immunohistochemical technique was used for expression of EGFR marker. EGFR staining pattern (membrane only, cytoplasm only or combined cytoplasm and membrane staining) was evaluated in the odontogenic epithelium of follicles. Data were analyzed with Mann-Whitney and logistic regression tests using the SPSS software (α=0.05).

Expression of EGFR marker with membrane-only staining pattern in follicles with radiolucencies >2.5 mm was significantly higher than follicles with radiolucencies <2.5 mm. (p value < 0.001). However, no significant differences were detected between the two groups in cytoplasm-only pattern (p value = 0.13) and combined cytoplasmic and membrane pattern (p value = 0.13).

The number and intensity of stained cells in membrane-only pattern were higher in follicles with radiolucencies >2.5 mm compared to follicles with radiolucencies <2.5 mm, indicating faster cell proliferation. Therefore, it is suggested that third molars with radiolucencies >2.5 mm be removed as soon as possible. However, the absence of abnormal radiolucency does not indicate healthy follicles without pathologic changes.

Self-etching fissure sealants have been introduced recently, leading to elimination of etching and rinsing, reducing working time and consequently increasing child cooperation. This clinical study was conducted to compare the retention rate, caries occurrence and marginal integrity of a self-etching fissure sealant (Prevent Seal) with a conventional sealant (Concise) over a12-month period. In this clinical trial 192 first permanent molars of 48 children aged 7-9 years were selected. Self-etching sealants were randomly used for first permanent molars on one side of the mandible and contralateral side of the maxilla and conventional sealants (etch-and-rinse) were placed on the remaining first permanent molars. Clinical evaluation was performed at 3-, 6-, and 12-month intervals by a single blind examiner. The retention was classified as complete retention, partial loss and total loss. Caries incidence was assessed. Marginal integrity of sealants was also evaluated with modified U.S. Public Health Service (USPHS) codes. Data were analyzed with Friedman’s, Wilcoxon’s signed rank and McNemar’s tests using SPSS statistical software (α=0.05). At the end of 12 months Concise had higher retention rates (87.5%) than Prevent Seal (12.5%), with statistically significant differences (p value < 0.001). Regarding marginal integrity of the sealants, Concise yielded significantly better results than Prevent Seal at all the follow-up examinations (p value < 0.001). However, there were no significant differences in caries incidence between the two groups (p value = 0.99). The results indicated that retention rate and marginal integrity of self-etching sealants are less than those of conventional ones at 12-month evaluation period.

Denture stomatitis is an important disorder as a result of denture wearing in geriatric populations caused by Candida albicans colonization. Tissue conditioners are used for better adaptation of denture surface with the oral tissues to prevent denture stomatitis; however, these materials encourage adhesion and colonization of most oral microbial flora, particularly Candida species. The aim of this study was to compare C. albicans adhesion and colonization on three commonly used tissue conditioners. In this in vitro study, 18 discs, measuring 5 mm in diameter and 1 mm in thickness, from the three commonly used tissue conditioners (Visco-gel, GC-Reline, and Acrosoft(were incubated in 1´105 cfu/mL Candida albicans suspension for 48 hours at 37ºC to form an experimental biofilm. Tissue conditioner discs were then rinsed with sterile physiologic serum and finally the colonized Candia cells were cultured on Sabouraud’s dextrose agar plates. Isolated colonies were counted and compared between the three disc groups using ANOVA and a post hoc Tukey test. Statistical significance was defined at p ≤ 0.05. Visco-gel and Acrosoft tissue conditioners with the average colonization of 14378.9 cfu/mL and 32227.2 cfu/mL had the maximum and minimum viable colonized Candida cells, respectively in the present study (p value = 0.0001(. Gc-Reline tissue conditioner exhibited moderate Candida colonization with 22342.8 cfu/mL. The results of the current study showed that different tissue conditioners had different resistance to in vitro adhesion and colonization of Candida albicans. Use of tissue conditioner with more inhibitory properties for Candida colonization is suggested.

Determination of condylar inclination is very important in dentistry. Condylar inclination is specific for each patient. Inaccuracy registration of condylar inclination can result in problems for posterior teeth disocclusion or multiple occlusal interferences. The aim of this study was to evaluate the relationship between the inclination of posterior slope of articular eminence according to a transcranial radiographic technique and the values obtained from intraoral protrusive bite records.

In this clinical study, 30 patients (13 males and 17 females) with an average age of 20‒40 years, with no sign and symptoms of temporomandibular disorders, were evaluated and two transcranial radiographies were taken from the right and left sides. Outlines of articular eminence, mandibular fossa and postglenoid process were drawn. The most inferior point of articular eminence and posterior glenoid process were named Tb and Pt, respectively. The eminence line was drawn and the angle between eminence line and Pt-Tb line was determined. Protrusive bite records were registered by polyvinylsiloxane. Each patient’s cast was mounted in the Denar Mark II articulator; condylar inclination was determined and compared with radiographic values. Pearson’s correlation coefficient and independent samples t-test were used for statistical analysis (α=0.05).

The means ± SD of posterior inclination of articular eminence were 39.5±5.7 and 38.8±5.4 on the right and left sides, respectively. The mean condylar inclinations ± SD obtained from protrusive bite records were 29.4±4.5 and 30.2±4 on the right and left sides, respectively. A relatively strong linear correlation was observed between the radiographic and protrusive bite records for determination of condylar inclination (p value < 0.05).

Under the limitations of the present study it can be concluded that in patients in which determination of condylar inclination by intraoral method is difficult, transcranial radiography can be used for adjusting condylar guidance of articulators; however, further studies are necessary.

The success of fixed prosthodontics requires a precise registration of the prepared teeth and finishing line, which necessitates finding to simple technique of impression taking so that an acceptable impression with record of details can be achieved. This research was performed to evaluate the effect of the second wash of Speedex impression material in one- and two-step impression technique on marginal adaptation of the crown. In this in vitro study a laboratory model with two metal dies (similar to the 2nd premolar the 2nd molar) and condensation silicone impression material (Speedex) were used. Impressions were made in four techniques (one-step, one-step with second wash, two-step with 2 mm of space, two-step with a second wash). Each technique was repeated 15 times and 60 impressions were obtained, which were poured with Type IV dental stone. On each die a wax pattern of a three-component bridge was framed and casting was carried out with a metal alloy. The marginal fitness of the frames was viewed and measured under a stereomicroscope at ×100 magnification with a digital micrometer in four areas. The results were analyzed by Tukey test and ANOVA. The least and greatest marginal gaps were observed in the anterior abutment with the two-step technique and the posterior abutment with one-step technique with a second wash (69.56 and 85.59 microns, respectively). The amounts of marginal gaps were clinically acceptable in all the four methods. There were no significant differences between the one-step and two-step techniques (p value = 1) and between one-step technique and two-step technique with a second wash (p value = 0.6). For each four technique the amount of marginal gap was acceptable; therefore, a second wash can be added to the primary wash to achieve more precise impressions with registration of details and finishing line. However, further evaluations are necessary.

Infectious endocarditis might occur by oral microbial flora subsequent to dental procedures leading to bleeding in the oral cavity. Therefore, the dental practitioner should be able to prescribe appropriate antibiotics in the prophylactic measures against bacterial endocarditis during dental procedures. The aim of this study was to evaluate the knowledge of general dental practitioners and senior dental students about the principles of antibiotic prophylaxis in children with cardiac problems in Isfahan. This cross-sectional study was carried out in winter 2010 in Isfahan. After data collection, a questionnaire was designed and distributed among 111 male and female general dental practitioners and senior dental students. Data was analyzed by one-way ANOVA, Levene’s test and t-test using SPSS 11 (α = 0.05). The results showed that senior dental students (mean=12.28 ± 3.12, p value = 0.018) and recently graduated dental practitioners (mean 12.21 ± 3.33, p value = 0.031) were in the medium acceptable level of knowledge compared to other groups with more job experiences. General dental practitioners with more than 17 years of job experience (mean = 8.84 ± 2.66, p value = 0.06) achieved the lowest score. Recently graduated dental practitioners and senior dental students had a higher knowledge level about the principles of antibiotic prophylaxis in children suffering from heart diseases, which might be attributed to being in the academic atmosphere of the university and their greater and easier access to the relevant references.

The use of sophisticated radiographic techniques is absolutely necessary in dentistry. The use of these techniques exposes the sensitive organs of head and neck to x-rays. The aim of the present study was to investigate the absorbed dose of the thyroid gland in conventional spiral and spiral computed tomography techniques.

In this experimental study, 10 TLD GR-200 circular dosimeters (Thermoluminans Detector) were used in male RANDO-like phantom (head and neck segment, i.e. the first 10 segments) in order to determine the radiation dose absorbed by the thyroid gland. Then spiral computed tomographies were provided from the anterior and posterior regions of the maxilla and mandible along with a lateral Scout view as a guide. Conventional spiral tomographies were prepared from the maxilla, mandible and both jaws with a panoramic radiograph as a guide. Data was analyzed using Kruskal-Wallis and Mann-Whitney tests using SPSS 11.5 (a = 0.05).

The highest and lowest thyroid gland absorbed doses were observed with computed tomography of both jaws and conventional spiral tomography of the anterior maxilla, respectively (5.92 ± 0.01 and 0.79 ± 0.01 mSiv). The mean amount of the absorbed dose by the thyroid gland was lower in the conventional spiral tomography compared to computed tomography. The two techniques revealed significant differences in the absorbed doses except for conventional spiral tomography in the posterior and anterior regions of the mandible (p value = 0.276).

According to results of the present study, the absorbed dose of the thyroid gland in the conventional spiral tomography in different regions of the jaws was less than CT scan techniques. As a result, it appears the use of conventional spiral tomography is preferred over CT scans in limited regions where three-dimensional and cross-sectional views are required.

Oral conditions result in physical, social, psychological and economic problems for the child and the family. The aim of this study was to evaluate oral health status in 8-11 year-old primary school students of Isfahan and its effect on their family.

In this cross-sectional descriptive/analytical study 240 students in an equal proportion of girls and boys and their parents from primary schools in Isfahan were selected. The parents filled FIS (Family Impact Scale) questionnaire. The relationship between FIS and tooth decay, DMFT, dental trauma index (DTI), occlusion status, enamel developmental problems and general health were analyzed by chi-squared test, t-test, and Pearson’s and Spearman’s tests using SPSS 18 software (α = 0.05).

There was no significant relationship between tooth decay and FIS (p value = 0.07). The most abundant occlusion was Class I with a frequency of 56.7%, with no significant relationship between occlusion and FIS (p value = 0.09). There was a significant relationship between enamel hypoplasia and FIS (p value < 0.001). There was a significant relationship between trauma to permanent teeth and FIS (p value = 0.04).

The results of the present study showed a significant relationship between FIS and dental trauma, general health and enamel hypoplasia.

Stainless steel crown (SSC) is an extremely durable restoration with several clear-cut indications for use in primary teeth, including restoration after pulpotomy/pulpectomy, restoration of teeth with developmental defects, and large carious lesions involving multiple surfaces. The aim of this review article was to assess the efficacy of SSCs for the restoration of primary molars compared to other restorative materials.Review Report: Medline and ISI Web of Science were searched for scientific papers based on the use of SSCs in order to compare the efficacy and longevity of SSCs compared to other restorative materials from 1950 to 2010. Inclusion criteria were randomized clinical trials (RCTs) in English and human studies. Children with extensive decay, large lesions or multiple-surface lesions in primary molars have been treated with stainless steel crowns. Because of protection from future decay provided by their full-coverage feature and their increased durability and longevity, SSCs should be particularly considered in children who are treated under general anesthesia. The majority of clinical trials have recommended the use of SSCs in the restoration of primary molars due to successful treatment results and their efficacy and cost-effectiveness.

Toothpastes are one of the most widely sold and used dental products, with their use as one of the most popular oral hygiene behaviors in developed countries. A large variety of toothpastes are available on the market for different purpose, making it difficult for patients to select appropriate ones and for clinicians to prescribe the most useful one. This review provides details on the ingredients of toothpastes and their clinical use, trying to assist oral care practitioners in recommending appropriate toothpastes to their patients based on their individual needs. This review was carried out by running a search in various databases, including references books, PubMed, ISI Web of Science and Google search engine from 1973 to 2011 using the terms toothpastes, Periodontics and dental plaque. There are large varieties of toothpastes for different caries prevention, gingivitis prevention, anti-calculus, dentin hypersensitivity prevention and for tooth whitening, with a wide range of active and non-active ingredients, including abrasives, humectants, preservatives, thickening or binding agents, detergents, flavoring agents and therapeutic agents as fluoride, bacteriostatics, pyrophosphates, tooth desensitizing agents etc. Some studies have evaluated the effects, advantages and disadvantages of each ingredient. It is absolutely necessary for dental practitioners to have a sound knowledge of chemical compositions and ingredients of toothpastes to be able to assist their patients in selecting appropriate and efficacious toothpastes.