مجله دانشکده دندانپزشکی مشهد
سال چهل و دوم شماره 2 (پیاپی 105، تابستان 1397)

The formation of dental plaques is one of the underlying causes of denture-related stomatitis. This study was conducted to evaluate the effect of the concentration of ozonated water on the inhibition of the formation of Candida albicans plaque on the acrylic resin pieces.
In this study, 45 resin acrylic plates were contaminated by Candida albicans suspension, which were randomly divided into nine groups. They were treated with 0.2, 0.5, 1, and 2 µg/ml of ozonated water, 25 and 12.5 µg/ml of ozonized oil, 100,000 units of nystatin (positive control), distilled water, and olive oil (negative control). Thereafter, the solution obtained from rinsing the pieces was cultured in Sabouraud Dextrose Agar and the mean number of the colonies was Mann-Whitney U and kruskal-wallis tests were for statistical analysis.
The mean number of the colonies obtained at the concentrations of 0.2, 0.5, 1, and 2 μg/ml of ozonated water was 24, 24.6, 23.6, and 14.4 colonies, respectively. Additionally, the mean number of the colonies obtained at the concentrations of 12.5 and 25 μg/ml of ozonized oil was 0 and 2 colonies, respectively. There was a significant difference between the solutions cultured in distilled water (146.6) and olive oil (98.8) in terms of the number of colonies (P Appropriate concentrations of ozonated water had an antifungal effect on Candida albicans. Therefore, further clinical studies are recommended to standardize and elaborate the guidelines for using ozone therapy.

Awareness of the localization techniques using conventional radiography is essential for all dentists. Although these techniques are theoretically taught to dental students, practical training is needed to enable them to use these modalities in localizing the anatomic structures. The aim of this study was to evaluate the ability of students and the effect of practical learning using educational model on applying vertical and horizontal tube-shift technique.
This study was conducted among 41 students of the second year of dentistry. They were assigned into two groups of “only theoretical training” and “practical traing with educational model”. All the students were tested 2 weeks and 6 months after teaching without previous notification. The scores were evaluated and compared by t-student , Mann-Whitney U and Wilcoxon tests.
There was no significant difference between the groups in the pre-test (P=0.171). Nevertheless, in the post-test, the students who were practically educated had a better performance than those with theoretical education (P=0.011). Moreover, no significant difference was observed between males and females considering the mean scores.
The practically educated group had a deeper understanding of the subject in comparison to those who were educated theoretically.

Peri-implantitis is characterized by irreversible lesions that are caused by microbial plaque, involving not only the soft tissue around the implant, but also the implant-supporting bone. In the peri-implant diseases, some cytokines are increased, and inflammatory mediators, which are observed in peri-implantitis, induce the activation of osteoclasts and bone resorption. The aim of this study was to compare the level of interleukin 23 (IL-23) in patients with peri-implantitis and those with healthy peri-implant tissue.
This clinical trial was conducted on 19 patients with peri-implantitis and 19 patients with healthy peri-implant tissue. The samples were collected from sulcular fluid/gingival pocket fluid by paper cone and placed in vials. The level of IL-23 was determined using ELISA reader. Furthermore, the relationship of IL-23 levels with bleeding, probing depth, and pus formation was analyzed. Data analysis was performed using independent t-test, Pearson correlation coefficient, and Spearman test.
According to the results, the level of IL-23 in the patients with peri-implantitis was significantly higher than that in the group with healthy peri-implant tissue (P As the findings indicated, the amount of IL-23 in the gingival fluid of the patients with peri-impinitis was higher than that of the healthy subjects. Probing depth, bleeding, and pus formation are directly associated with IL-23. Therefore, the evaluation of IL-23 level can be used in the diagnosis of peri-implantitis.

Class II malocclusion is an evolutionary problem caused by deviated maxillary and mandibular growth. Various types of orthopedic devices have been introduced to correct this malformation. The aim of the present study was to evaluate and compare the skeletal and dental effects of activator and Thurow appliances in patients with Class II malocclusion.
Method and Materials: This retrospective study was conducted on 26 patients with Class II malocclusion. The patients were within the age range of 9-12 years before the growth spurt and at the time of the treatment initiation and had Class II Division 1 malocclusion, Class II molar relationship, ANB of > 4, and overjet of > 5. They were under treatment for one year. The participants were divided into two groups of Thurow and Activator, based on the device used. The tracing of the lateral cephalometric radiographs was performed at the beginning of the treatment (T1) and 12 months after that (T2). Finally, the mean scores of cephalometric variables were compared between the two groups and between the two treatment stages (i.e., T1 and T2).Using independent T and Man-Whitney u test.
In the activator group, the variables of ANB, N-A-Pog, U1-L1, L1-MP, U1-NA, L1-NB, overjet, Co-A, and Co-GN were significantly different between the pre- and pot-intervention stages. Furthermore, regarding the Thurow group, a significant difference was observed between the two research stages in terms of SNA, ANB, N-A-Pog, U1-L1, U1-NA, overjet, overbite, and N-perpendicular A. Between the Thurow and activator devices, only L1-MP showed a statistically significant difference after the treatment.
As the findings indicated, Thurow device was only suitable for preventing maxillary growth and exerted no significant effect on the mandible. On the other hand, functional class II device (i.e., activator) was effective for stimulating the growth of the mandible and did not inhibit the maxillary growth.

To improve the quality of tooth-colored restorations, various equipment and materials are being used. In this study, we sought to determine the degree of conversion of metacrylate- and silorane-based composites using transparent blue matrix strip at different depths.
In this experimental-laboratory study, 48 specimens of methacrylate- and silylane-based composites were prepared in pre-made molds in thicknesses of 1, 2 and 3 mm. half of the specimens were cured with transparent polyester strips and the other half with blue strips, and then they were hardened by using a light-curing unit. The degree of conversion was determined by FT-IR. The degree of polymerization was assessed by comparing the IR absorption spectra between monomer and polymer specimens. The data were analyzed by performing Mann-Whitney and Kruskal-Wallis tests in SPSS.
The highest degree of conversion pertained to P90 composite with using transparent strip in 1 mm thickness (45.5±1.29), while the lowest degree belonged to Z350 composite with using transparent strip in 3 mm thickness (14.7±1.70). In comparison of the four groups, the silorane-based group with blue strip (41%) had the highest conversion degree, followed by the same composite (silorane) with transparent strip (39.6%). Conversion degrees in these types of materials were much greater than those in metacrylate-based types (21%).
In deep restorations with limited access to a light source, the use of silorane-based composites and blue polyester strips enhances the degree of conversion.

Several studies have reported the antibacterial effect of Teucrium polium extract. In this study, we sought to determine the effect of a chewing gum containing the aqueous extract of Teucrium polium on the level of salivary Streptococcus mutans.
In this double-blind clinical trial, 20 dental students were randomly assigned to two groups of intervention and control. The intervention group received a chewing gum containing the aqueous extract of Teucrium polium, and the control group received a chewing gum without any plant extract. Each person chewed the gum for 20 minutes three times a day (after each meal) for three weeks. Unstimulated saliva samples were collected at the beginning of the experiment before the use of the gums and one day after the final gum consumption. The quantitative polymerase chain reaction (qPCR) technique was employed to determine the bacterial level. The colonization rate of Streptococcus mutans was compared between the two groups by using t-test in SPSS, version 21.
There was no significant difference between the two groups in terms of Streptococcus mutans counts before the intervention (P>0.05). The consumption of Teucrium polium extract-containing chewing gum in comparison with the placebo gum significantly diminished the number of Streptococcus mutans colonies (P=0.002).
The results of this study showed that the chewing gum containing the aqueous extract of Teucrium polium significantly lowered the colonization rate of Streptococcus mutans in human saliva.

With the advancement of the instruments for oral surgeries, use of alternative methods instead of traditional scalpels has been evaluated, The present study aimed to compare the complications associated with electrosurgery techniques and use of scalpel during and after orthognathic surgery.
In this split-mouth designed study, 20 patient who were candidate for orthognathic surgery were enrolled. Symmetrical incisions were made using electrosurgical methods on one side of the jaw and routine techniques with a scalpel number 15 on the other side. Evaluation of the techniques was performed during the surgery and six weeks postoperatively based on specific parameters, including the cutting time, and rate of scar tissue formation. Finally, the collected data from the implications of the two methods were compared using Man-Whitney U- test.
Mean cutting time was 6.63±1.22 and 10.19±1.95 minutes in the electrical cautery and scalpel groups, respectively, which denoted a significant difference between the groups (P According to the results, cautery could lead to a more significant reduction in the cutting time compared to use of scalpel. Furthermore, the scar tissue produced in the electrocautery technique was significantly higher compared to scalpel, which could be due to the induced heat damage to the adjacent tissues.

Given the importance of enhancing the teaching ability of faculty members and the influential factors and considering the limited resources in this regard, the present study was conducted to evaluate the spiritual intelligence and its association with teaching ability in the faculty members of the dentistry school at Islamic Azad University in 2015.
In this analytical-correlational study, the spiritual intelligence of the faculty members was assessed using the Persian version of the standard King's health questionnaire (KHQ), the validity and reliability of which were confirmed. Moreover, the teaching ability of the participants was evaluated using the Persian version of the Alabama standard questionnaire with proper validity and reliability. In the KHQ, spiritual intelligence was scored based on a five-point Likert scale, and teaching ability in the Alabama inventory scale was scored based on a four-point Likert scale. Influential factors, such as age and gender, were also reviewed. Data analysis was performed using the Chi-square and Spearman tests.
In total, 132 questionnaires were distributed among the faculty members of the Dentistry Unit at Islamic Azad University, 96 of which were collected. Mean scores of spiritual intelligence and teaching ability were 58.8±15.4 and 92.1±17.3, respectively. The correlation between the spiritual intelligence and teaching ability of the faculty members was estimated at 0.301. Spiritual intelligence was observed to be higher in the female participants (P According to the results, spiritual intelligence and teaching ability had low correlation in the field of dentistry. Women with a broad teaching background and stable employment were observed to have higher spiritual intelligence, while teaching ability was higher in the married faculty members with stable employment.

Radiography is among the most effective paraclinical methods used for accurate diagnosis and treatment in dentistry. Considering the possible risks of X-ray exposure for patients, dentists are professionally obliged to have adequate knowledge in the accurate prescription of various radiographic techniques to minimize unnecessary radiographs. The present study aimed to survey the knowledge of general dentists regarding the correct prescription of various radiographic techniques in Rasht, Iran.
In this descriptive, cross-sectional study, 126 practicing dentists were visited and asked to complete designed questionnaires. Knowledge level of the participants was evaluated in nine domains regarding the accurate prescription of oral radiographs, and each domain was compared in terms of age, gender, and work experience. Data analysis was performed in SPSS version 21 using Chi-square and Kruskal-Wallis test.
Overall knowledge of the general dentists about the accurate prescription of oral radiographic techniques was acceptable. The highest knowledge level was observed in the pediatric field (78.6%), followed by the Bitewing techniques (54%) and panoramic radiography (40.5%). The lowest knowledge level was denoted in the case of high-risk patients for caries (40.5%). No significant association was observed between the gender and knowledge of the dentists (P=0.333), while age had a significant correlation with the level of knowledge (P=0.024).
Despite the acceptable overall knowledge of the dentists, the level of knowledge was variable in the nine studied domains. Therefore, it is recommended that retraining courses be implemented based on valid guidelines in order to improve the knowledge of dentists about dental radiographic techniques, particularly in cases of high-risk patients for dental caries, periapical techniques, and periodontal techniques.

Due to the association of post- and pre-endodontic pain, using non-steroidal anti-inflammatory drugs (NSAIDs) before root canal therapy could interfere with the subsequent inflammatory process and reduce post-endodontic pain. The present study aimed to compare the effectiveness of prophylactic gelophen, Advil (two types of NSAIDs), and placebo in controlling the pain after root canal therapy.
This triple-blind clinical trial was conducted on 48 patients with a vital, single root canal anterior tooth. The teeth samples were divided into three groups. The patients in each group received one capsule as pre-treatment prophylaxis, which contained gelophen, Advil or placebo depending on the codes. Standard root canal therapy was performed by a general dental practitioner. Level of pain in each patient was recorded before the treatment and at 6, 12, 24, 48, and 72 hours after the treatment using the visual analog scale (VAS). After collecting the data, mean pain score was compared in the study groups. Data analysis was performed using Chi- square and repeated measures ANOVA.
In the patients administered with Advil and gelophen, pain reduction was more significant than the placebo group at all the intervals after the treatment compared to the pre-treatment phase. However, no statistically significant difference was observed between the intervals in this regard (P>0.05).
According to the results, the prophylactic use of Advil and gelophen is effective in the reduction of post-endodontic pain, while there is no significant difference in their efficacy.