Caspian Journal of Dental Research

15-22

Authors: Effat Khodadadi , Nafiseh Ghasemi, Mehdi Pouramir* , Ali Bijani

Introduction: 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. Methods: 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. Results: 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. Conclusions: 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.

29-35

Authors: Mehdi Ravadgar , Valiollah Arash , Hamid Pachenari*

Introduction: 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. Methods: 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. Results: 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. Conclusions: 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.

42-47

Authors: Ali Nozari , Tahere Esmaeilpour , Soleiman Fijan* , Mahin Salmannejad

Introduction: 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. Methods: 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 Results: 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 cells' 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. Conclusions: 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.