مجله تحقیق در علوم دندانپزشکی
سال نهم شماره 4 (پیاپی 34، زمستان 1391)

Reports indicate an increase in the resistance of oral bacteria to the antibiotics. This study was conducted with the aim to compare the antibacterial effects of colloidal Nanosilver and Nigella sativa oil.

In this experimental laboratory study, the disk diffusion method was used on 76 samples to evaluate the anti-bacterial properties of Nigella sativa oil extract in concentrations of 330mg/mL (up to 10.312 mg/ mL) and similar properties of Nanosilver in concentrations of 3.125 to 3500ppm.The samples were divided into 2 groups of oral bacteria consisting of Streptococcus mutans and S.sanguis. The results were compared with anti-bacterial effect of the standard disk of amoxicillin (25 µg). The growth medium consisted of Mueller Hinton agar plates in which standard strains of bacteria with 0.5 McFarland concentrations were cultured. The bacterial inhibitory zone of each disk was measured and the data was analyzed using the ANOVA statistical test.

The Nigella Sativa oil in concentration of 330mg/mL and Nanosilver in concentration of 3500 ppm demonstrated an inhibitory zone of 22-33.5mm respectively for S. mutans and 9.75-11 mm respectively for S.sanguis. The inhibition zone of standard amoxicillin disc (25 µg) was 19.75 – 21.75mm.

Colloidal Nanosilver showed the highest antibacterial activity against both strains of the bacteria. The antibacterial effects of Nigella sativa and amoxicillin were similar on S. mutans whereas, Nigella stavia was found to be more effective than amoxicillin on S.sanguis.

Oral Lichen Planus (OLP) is a chronic immunologic disorder with unknown etiology. Stress and anxiety are risk factors for OLP and Vitamin B12 and Folic acid have been proved to be effective micronutrients for prevention of anxiety and depression. The purpose of this study was to assess the serum levels of Vitamin B12 and Folic acid in patients with Oral Lichen Planus

This descriptive- analytic study selected 64 subjects (32 patients with OLP and 32 healthy samples) in whom the serum levels of folic acid and Vitamin B12 were measured with Elexis 2016 and electro-chemi-luminsence method. The results were analyzed with SPSS software (version 16) and for each individual the T-test was used for data analysis.

Serum levels of vitamin B12 in healthy subjects was 284.7±99.5 Pg/ml compared to 288± 165.7 Pg/ml in patients with oral Lichen Planus. Serum levels of folic acid in healthy subjects was 12.4±4.2 ng / ml whereas in patients with OLP it was found to be 9.45±4 ng / ml. The T-Test showed that there is no statistically significant difference in B12 levels between healthy subjects and patients with OLP.(P=0.93) However, the serum levels for Folic Acid was significantly lower in patients with OLP compared to healthy subjects. (p=0.03).

Folic acid deficiency may have a role in the pathogenesis of OLP. More studies are needed to prove such relation.

In recent years, LED curing units have become more popular among the dentists due to their overall superior attributes. Therefore, assessment of the leakage levels in resin restorations after curing with these nearly new devices is a priority. This study was conducted with the aim to compare the microleakage in class V restorations after being cured with LED and QTH light units. Microfilled composite Z100 (3M ESPE,USA)was used on 30 samples in this experimental study. Separate class V cavities (3mm× 2mm×2mm) were prepared on buccal surfaces of 30 sound freshly extracted premolars and then filled with Z100 composite resin. Samples were divided into two groups of 15 each. The first group was cured with a halogen light curing unit (Coltolux 2.5,USA) and the second with a LED unit (Apoza,Japan) for 40 seconds. Then, the specimens were subjected to thermo cycling (5-55º for 500 cycles). Afterwards, they were covered with a nail polish 1 mm away from cervical margin and they were kept in 50% aqueous silver nitrate solution by weight for 2 hours. The samples were then placed in developing solution for 6 hours, after which, the specimens were sectioned and observed under stereomicroscope at x40 magnification. The data was analyzed with Mann Whitney and Fisher tests. Microleakage levels in gingival and occlusal margins of resins restoration, in LED and QHT units were 1.13±0.35 and 1.6±1.05 and 0.2±0.43, 0.13±0.35 respectively. There was no significant difference between the efficacy of LED and QHT units in terms of microleakage levels found in the composite resin restorations (p<0.2), (p<0.4). Application of QTH or LED curing unit to cure Z100 composite leads to similar microleakage levels in enamel/dentin margins.

The role of streptococcus mutans, the main microorganism associated with dental caries and the most pathogenic bacteria of oral cavity has been stressed in dental caries. Hence the aim of the present study was to evaluate the effect of the nutrition pattern on salivary streptococcus mutans counts among 5-years-old children of Tehran. 150 eligible children were included in this case-control study. Case group included 71 children who with values higher than 104 CFU. Control group consisted of 79 children with similar conditions but with values less than 104 CFU. Nursing patterns, duration and frequency, as well as tooth brushing habits were evaluated by questionnaire. The participants’ DMFT index was calculated through clinical examination with a mirror and explorer. The saliva samples were obtained from the dorsal surface of the tongue by using a sterile swab for streptococcus mutans isolation. The relationship between the nutrition pattern and salivary streptococcus mutans counts was analyzed by chi-square test. 73/4% of Children in control group and 31% of Case Group were breastfed and 26.6% of control group and 69% of Case group were breastfed and bottle fed. There was significant different between two groups. (P<0.001), (OR:6.1) The infantile nursing pattern has an impact on streptococcus mutans counts. This can be a finding that may well be used to improve the nutritional pattern during infancy and early childhood.

Diagnosis of dental caries with Diagnodent device has been found to be comparable to visual and radiographic diagnostic methods. The aim of this study was to determine the effect of Aging, Staining, and Bleaching on Diagnodent readings in composite resin restorations. This was an experimental in vitro study in which 108 disk-shaped specimens were fabricated from 6 different composite resins including: 3 M p60, Kerr point 4, Vivadent Heliomolar, Ultradent flow, Tetric flow and Kerr flow. The samples were divided into 3 groups. Group 1was aged in water, group 2 was stained with tea and group 3 was bleached with 16% Carbamide peroxide. Specimen Fluorescence was measured with Diagnodent (Kavo- U.S) before and after these treatments. Data were analyzed using Mixed repeated Measure Model ANOVA. This study was performed on 108 composite resin specimens. All samples aged in water showed higher reading values; only Tetric flow exhibited a lower mean value (P<0.001). All samples stained with tea showed higher readings(P<0.001) and all materials bleached with 16% Carbamide peroxide were reported to have lower values; only Kerr flow exhibited a higher mean value than basic situation. The results indicate that aging and staining can result in an increase in the Diagnodent readings of the composite resin restorations while bleaching lead to a decreased the readings. However, the reported differences in Diagnodent readings were not significant enough to result in a false positive diagnosis of caries.

The purpose of this study was to determine the frequency of EGFR marker expression in oral Squamous Cell Carcinoma (SCC) and correlative factors. A descriptive study was conducted on 40 paraffin embedded blocks of oral SCC. Immunohistochemical staining(IHC)was done for EGFR and EGFR expression was evaluated on the basis of extent and intensity of EGFR immunolabeling in tumor cell membranes. Classification was done on a four point scale as follows: 0(no labeling, or labeling in <10% of tumor cells); 1(weak labeling, homogeneous or patchy, in≥10% of tumor cells); 2(moderate labeling, homogeneous or patchy, in> 10% of tumor cells);3(intense labeling, homogeneous or patchy in >10% of tumor cells). These categories were subsequently grouped into two wider categories for data analysis: absent/weak labeling (0 or 1)and moderate/intense labeling (2 or 3).The data was analyzed by Fisher exact test. The high expression was shown in 45% of OSCCs. There was significant correlation among gender with EGFR expression (p=0/02). In this study EGFR expression was significantly higher in female than male, that can be impress biological behavior of tumor.

Avulsion is one of the most complicated cases of dental trauma. If treatment is delayed; it could have a negative impact on proper function as well as occlusion. The patient may also be faced with esthetic deformities and mental problems. One of the most common causes of dental trauma is sport activities. Martial arts instructors are the first ones to come into contact with individuals who have suffered a dental trauma during a sports activity and they often have the opportunity to replant an Avulsed tooth. This study was done with the aim to evaluate the knowledge of female martial arts instructors regarding tooth avulsion and related factors.

This descriptive study included 112 female participants who were all martial arts trainers from 18 different sports complexes spread out in 5 districts of the city of Tehran. In addition to a questionnaire that was handed out to each participant, all trainers were asked individual question through an interview and their knowledge along with related factors were assessed afterwards. The linear regression method and spss software (version 11.5) was used to analyze associated factors.

The survey on 112 participants indicated that 34 people (30.3%) had good knowledge, 58 people (51.6%) had average knowledge and 20 people (17.1%) had weak knowledge of dental trauma. The level of knowledge was significantly associated with working experience (P =0.03) and educational level (P = 0.002)

Most martial arts instructors do not acquire sufficient knowledge of tooth avulsion and the emergency means of re-implanting a traumatized tooth. Proper education in this area seems to be a necessity for all sports trainers.

In the last decade, implant surface treatment in order to maintain rapid and improved osseointegration has been considered worldwide. This study reviews methods used to increase osseointegration of dental implants by surface modification techniques.

A search in PubMed was performed by typing the following words: dental implant surface, implant surface treatment, implants surface modification and 48 relevant articles were extracted from 2000 to 2012.

surface characteristics of dental implants such as surface chemistry, thickness of the TiO2 layer, wettability, surface charge, and surface roughness can increase the rate and strength of osseointegration. Many of these methods have been shown to have clinical efficacy (>95% over 5 years).

The exact role of the surface chemical characteristics and surface topography in the primary events of osseo integration has not been clarified precisely. In addition, human clinical trials that compare current methods simultaneously in a split mouth design are rare. Many of these studies were in vitro and generalizing the results of these studies to the clinical practice is difficult. Therefore, more clinical trials are suggested.

Adenoid Cystic Carcinoma (ACC) is a relatively rare epithelial tumor of the salivary glands in the maxillofacial region. We present a case of central ACC involving the anterior portion of mandible in a75-year-old woman. A Case of central adenoid cystic carcinoma is reported in a 75-year- old woman who presented with a soft tissue swelling in the anterior segment of her mandible with slow growing pattern from 9 years ago. Radiographic findings in her panoramic x-ray revealed a large radiolucent area, with irregular margins. The histopathological analysis, revealed the presence of tubular adenoid cystic carcinoma. The patient was surgically treated by with partial mandibulectomy and her CT scan revealed no evidence of lung metastases. The patient passed away in two-year follow up due to distant metastasis. It is mandatory to include malignant salivary gland tumors in differential diagnosis of pathologic lesions of the anterior segment of mandible with bone destruction.