Caspian Journal of Dental Research
Volume:2 Issue: 2, Sep 201313

Growth and proliferation of the remaining microorganisms within the root canals may destroy the surrounding tissue of the root and leads to periapical lesion. Consequently, the complete elimination of microorganisms from the root canal is an important goal of endodontic therapy. Endodontic sealers do not provide complete seal in root canal system, and micro spaces have always remained between the material and canal walls that lead to penetration of these spaces, so, an antibacterial activity is essential for sealers. The aim of the present study was the in vitro evaluation of antimicrobial activity of the three endodontic sealers on two microorganisms. To study the effect of each sealer; AH26, MTA Fillapex and ADseal on Enterococcus Faecalis and Lactobacillus bacteria 10 samples were considered. In this experimental study, 60 plates were exposed to bacteria and 10 plates were considered for control group. Sealer antibacterial effect on bacterial growth was studied after 48 hours. Firstly, the freshly prepared sealers were poured inside the micro tube and diffused in the wall of the micro tube. Then solution of nutrient broth was poured into a micro tube and the determined volume of solution of bacterial suspension was added into a microtube and was kept 24 hours in the incubator to grow the bacteria. Then, it was poured in the plates of blood agar and cultured after 24 hours and then the colonies grown on the plates were counted in sufficient light. The data were analyzed with MANOVA statistical test and SPSS Version 18. Most bacteria grew in the plates of ADseal sealer and MTA fillapex sealer with means of 5113.00CFU and 3077.00CFU respectively, while the lowest number of bacteria grew in the plates of AH26 sealer with a mean of 1345.15CFU. Most antibacterial activities of each enterococcus faecalis and lactobacillus bacteria sample was for AH26 sealer and MTA fillapex sealer. The lowest antibacterial activity was for ADseal sealer.

The antioxidant properties of chocolate and other flavored additives besides the sugar added to milk raises the question about the acidogenecity of flavored milk. This study was conducted to measure the pH changes of dental plaque and saliva after the consumption of flavored milk and evaluate the antioxidant property of them. This study was performed on 42 samples of dental plaque and 42 samples of saliva in 6-11 year old school going children. Milk with flavors of strawberry, chocolate, banana, honey and slim milk were evaluated, all from the same manufacturer with a similar production date. At the beginning of the study on the first day, children were given thorough oral propHylaxis and they were instructed to avoid any method of oral hygiene for 48 hours to permit enough plaque deposition. On the third day the children were divided into 7 groups, 6 children in each group. The supra-gingival plaque was collected through the help of an excavator #3 which was pulled twice with the same force on the tooth surface. The saliva was collected using spitting technique. Each child swished 10 cc of milk for 1 minute in his/her mouth. Fresh plaque samples after 5, 10, 20 and 30 minutes and saliva samples immediately, after 5, 10, 20 and 30 minutes were collected. The pH of the samples were recorded by a pH testing apparatus (Basic 20+, Crisom). To evaluate the antioxidant property of studied milk, Frap test was performed. The collected readings were reported as mean±SD and analyzed by ANOVA repeated measures, Post hoc Tukey and Paired T-test. In this study, p≤0.05 was considered as significant. After 30 minutes, honey milk caused the least drop 0.74±0.30 and banana milk caused the highest drop 1.38 0.25 in plaque pH (p≤0.05). After 30 minutes, the pH of saliva showed no significant difference compared to the initial pH. Chocolate milk contained the highest (1000 micromol/liter) and banana milk the lowest (706.25 micromol/liter) antioxidant concentration. Because of the highest antioxidant properties and reduction of dental plaque PH to a lesser extent, milk with honey, chocolate and coffee is more recommended for children.

Dental wastes are a main part of urban solid wastes in each society and have pathogenic agents and toxic chemicals, which put health of patients, personnel and other referees to dental clinics in danger. The present study was done to recognize the quality and quantity of the different generated wastes at various parts of the Faculty of Dentistry-Babol University of Medical Sciences.

The whole solid wastes generated in the odd and even days (Monday, Tuesday and Wednesday) of the middle of the week from the second month of each season were examined. Various dental solid wastes including general, infectious and hazardous chemical wastes were weighted by typical scale.

The generation rate of the solid wastes were: total dental wastes: 291.2 kg including general solid wastes: 251.3 kg (%86.3), infectious wastes and sharps: 38 kg (%13) and hazardous chemical waste: 2 kg (%0.7). The total amount of wastes in a year was 69888 kg. The solid wastes are daily produced according to each active dental unit as total, domestic-type, infectious and the hazardous chemical wastes were 3.07 kg, 2.65 kg, 0.4 kg and 0.02 kg, respectively.

Considering the quality and quantity of the generated dental solid wastes especially infectious wastes and their unfavorable effects on the people's health and environment, it is necessary to compile a distinct policy for the management of these medical solid wastes. Also, holding training workshops, knowledge of the staffs in the dentistry care centers should be increased to avoid possible dangers.

When using sliding mechanics for space closure during orthodontic treatment, friction occurs at the bracket-wire interface. The aim of this study was to evaluate the frictional resistance between monocrystalline (ICE) brackets and Stainless Steel, Beta TMA and NiTi wires. In this experimental study, we used 5 different types of orthodontic wires. Brackets and wires were divided in to 5 groups: 1-(monocrystalline+stainless steel 18) 2–(monocrystalline+stainless steel 19×25) 3-(monocrystalline+Beta-TMA) 4–(monocrystalline+Beta TMA 19×25) 5-(monocrystalline+NiTi 18). Instron Universal Testing Machine was used to investigate the static frictional resistance. The angulation between bracket and wire was 0 and the wires were pulled through the slots at a speed of 10 mm/min. Tests were performed 10 times for each group in artificial saliva. The average of 10 forces recorded was considered as static friction. One-way ANOVA and SPSS Version 18 and LSD post hoc test were used to evaluate the results of the study. The mean static frictional force for each group was: group1: 0.82±0.14, group 2: 1.09±0.30, group 3: 0.87±0.53, group 4: 1.9±1.16, group 5: 1.42±0.30. There was a significant difference when comparing the two groups of similar wires in terms of shape (round or rectangular cross-section) as when comparing Beta TMA 18 and 19×25 arch wires with each other, the obtained p-value was 0.023, while the obtained p-value for the comparison of stainles steel arch wires was 0.034. The result of this study shows that Stainless Steel 18 wires generate the least amount of friction and round wires produce less friction than the rectangular wires. Beta TMA wires generate the highest amount of friction.

In orthodontic treatment, it is essential to establish a satisfactory bond between enamel and bracket. After the self-etch primers (SEPs) were introduced for the facilitation of bracket bonding in comparison to the conventional etch-and-bond system, multiple studies have been carried out on their shear bond strengths which have yielded different results. This study was aimed at comparing shear bond strengths of the stainless steel metallic brackets bonded by three bonding systems. In this experimental in vitro study, 60 extracted human maxillary premolar teeth were randomly divided into three equal groups: in the first group, Transbond XT (TBXT) light cured composite was bonded with Transbond plus self-etching primer (TPSEP); in the second group, TBXT composite was bonded with the conventional method of acid etching; and in the third group, the self cured composite Unite TM bonding adhesive was bonded with the conventional method of acid etching. In all the groups, Standard edgewise-022 metallic brackets (American Orthodontics, Sheboygan, USA) were used. Twenty-four hours after the completion of thermocycling, shear bond strength of brackets was measured by Universal Testing Machine (Zwick). In order to compare the shear bond strengths of the groups, the variance analysis test (ANOVA) was adopted and p≤0.05 was considered as a significant level. Based on megapascal, the average shear bond strength for the first, second, and third groups was 8.27±1.9, 9.78±2, and 8.92±2.5, respectively. There was no significant difference in the shear bond strength of the groups. Since TPSEP shear bond strength is approximately at the level of the conventional method of acid etching and within the desirable range for orthodontic brackets shear bond strength, applying TPSEP can serve as a substitute for the conventional method of etch and bond, particularly in orthodontic operations.

Tooth avulsion is defined as the complete displacement of the tooth from its alveolar socket which causes damage to the periodontal ligament structure, cementum, alveolar bone, gingiva, and dental pulp. The purpose of this study was to determine the ability of long-shelf life honey milk to serve as a temporary storage medium for the maintenance of periodontal ligament (PDL) cell viability on avulsed teeth. PDL cells were obtained from premolars extracted for orthodontic purposes which were clinically healthy and had healthy gingiva (i.e. not inflamed).Then, 8×10³ cells were seeded in each well of 96-well plate. and Afterwards treated with long-shelf life milk and honey milk, Hank’s Balanced Salt Solution (HBSS) and fresh milk. Different incubation periods were 1, 3, 6, and 9 hours. Dulbecco’s Modified Eagle Medium (DMEM) and dry medium were considered as positive and negative control media, respectively. Cell viability was determined by using the MTT (Thiazolyl Blue Tetrazolium Bromide) assay. Data were statistically analyzed with one-way anova, two-way anova and post hoc Scheffe tests. A level of p≤0.05 was accepted as statistically significant The results indicate that all media performed significantly better in maintaining PDL cell viability than the negative control at all time periods. (p≤0.001) After 9 hours, Percentage of viable PDL cells in long-shelf life honey milk, long-shelf life milk and HBSS were 82±0.82, 75±8.13 and 87±2.78 respectively. Furthermore cell's viability in both long-shelf life honey milk and HBSS was significantly better than fresh milk medium (p=0.003). Moreover, the results of One-way ANOVA showed long-shelf life honey milk were more effective in preserving the PDL cell viability as well as HBSS after 9 hours. According to the study results, long-shelf life honey milk considered as appropriate storage media which are comparable to HBSS. These media are not only able to keep more cells viability after 9h compared to the expensive commercial solutions, but are also be easily accessible.

The purpose of this study was to determine the accuracy of panoramic radiograph in locating the position of lingula as an index to estimate the location of mandibular foramen. The distance measurement in this study was carried out on 30 dry mandibles, composed of at least 2 first molars and one canine. Photography and panoramic radiography of the mandible was performed in a steady reproducible position. 10 lines (including 2 horizontal and 8 vertical) were drawn from the lingula to the anterior and posterior borders of ramus, the coronoid process and the lower border of the mandible. These lines were measured and compared in photographs and panoramic radiographs. The data were analyzed using SPSS 20 software, paired t-test, Pearson correlation and linear regression analysis. Considering all different distances, there was no significant difference between the findings of panoramic radiographs and photographs with regard to 3 indices as follows: cd (posteroinferiormostpoint of mandibular foramen to the posterior border of the mandible); ln (5 mm behind the postero inferior most point of mandibular foramen to the lower border of mandible) gh(5 mm ahead of superior most point of mandibular foramen to the coronoid notch). Whereas, a significant difference was observed in other indices. It seems that the Panoramic radiograph is an inaccurate guide to display the precise location of the lingula.