مجله تحقیق در علوم دندانپزشکی
سال شانزدهم شماره 2 (پیاپی 60، تابستان 1398)

Plaque-induced gingivitis is a common gingival disease. There are some limitations in mechanical methods to promote plaque control which is why chemical methods have been introduced. Chemical toothpastes have side effects like hypersensitivity and staining, so the tendency is growing towards herbal toothpastes. Our aim in this study was to evaluate the effectiveness of Aloevera tooth paste on gingivitis. This was a Single blind cross over clinical trial study which was conducted on 20 dental students ( 10 male, 10 female with the average of 24.5±4 years) who had gingivitis. Then, they were divided into 2 groups: The first group used the Aloevera toothpaste for 30 days and PI and GI was recorded. They had been washed out for 2 weeks and after that they used the Fluoride toothpaste for another 30 days. Again, PI and GI was recorded. In the second group the toothpastes were used in an opposite order. The Wilcoxon test was used to evaluate statistical analysis.the level of significance was set as 0.06. There was no significant difference in periodontal records between toothpastes after 30 days of administration. After 30 days, PI changed from 2.14±1.3 to 1.84±1.02(P<0.098) and GI changed from
0.74 ±0.62 to 0.25±0.46(P<0.068) and the P-value between the toothpastes was P<0.07 for PI and P<0.308 for GI. Aloevera toothpaste may have the same effect on PI and GI as the Fluoride tooth paste, So it can be concluded the this toothpaste could be used instead of conventional chemical toothpastes.

Over the years, improvments have been done to simplify clinical bonding procedure. One of these material is Transbond™ Plus Self Etching. The aim of this study was to evaluate the effect of saliva contamination and reusing Transbond™ Plus Self Etching Primer (SEP) on shear bond strength of orthodontic brackets. Fifty premolars divided into five groups of 10. Orthodontic brackets were bonded with Transbond XT adhesive (3M, Unitek) using the following treatment: Group1- Transbond™ Plus Self Etching Primer(SEP)/ Transbond XT adhesive/ Curing. Group2- Self-Etching Primer/ Curing/ Transbond XT adhesive / Curing. Group3- Self-Etching Primer/ Curing/ saliva contamination/ Transbond XT adhesive/ Curing. Group4- Self-Etching Primer/ Curing / saliva contamination/ Self-Etching Primer/ Transbond XT adhesive/ Curing. Group5- Self-Etching Primer/ Curing/saliva contamination/ Self-Etching Primer/ Curing/ Transbond XT adhesive/ Curing. Samples were stored for 24h in distilled water at 37 ˚C, then thermocycled for 1000 cycles (5-55˚C). Shear bond strength of each sample was obtained using a universal testing machine. Data were analyzed statistically. Using one way anaylisis & variance, Tukeey and Scheffe. Clinically acceptable bond strength was in all groups. There was no statistically significant difference between the groups. Saliva contamination has no statistically significant effect on the shear bond strength of Self etching primer, however light curing of Self etching primer, before saliva contamination, increased the bond strength.

Microgap in the implant-abutment interface is one of the main challenges in the treatment of two-piece implants. This study aimed to investigate the effect of two types of abutments (zirconia and titanium) on microgap at implant-abutment interface area under oblique cyclic loading in vitro.  In this in vitro study, 12 implant-abutment assemblies were used, each containing six sets with either zirconia or titanium abutments and vertically mounted in the modified resin blocks of auto-polymerized polyester base. The specimens were then subjected to oblique cyclic loading of 75 N at a 30 ± 2 degrees angle to the longitudinal axis of the implant with a frequency of 1 Hz in 500,000 cycles, equivalent to 20 months of human mastication. For the microgap analysis, direct observation from the top was used with a scanning electron microscopy (SEM) with a magnification of 5000×. Statistical analysis was used to compare the microgap before and after the application of loading with the paired t-test.   The amount of microgap before force application in the titanium abutment group was (2.6±0.7) significantly higher than the zirconia abutments (1.9±0.5) (P = 0.033). The dimension of the microgap in the titanium abutment group significantly decreased following cyclic loading (P = 0.047), but in the zirconia group showed a significant increase (P = 0.035). Finally, the dimension of the microgap following oblique cyclic loading in the titanium abutment group (2.0±0.8) was not significantly different with the zirconia abutments (2.7±0.9) (P = 0.262). The difference of microgap after oblique cyclic loading between two types of titanium abutment and zirconium abutment is not significant, and both are clinically acceptable.

Mouthwashes are one of the tools used to reduce decay. Fluorin total mouthwash is a new mouthwash, so far no research has been done on its effect on streptococcus mutans.
In this study, the diameter of growth inhibition zone for streptococcus mutans bacteria was compared between fluorin total and chlorhexidine mouthwash. First, we cultured the bacteria on blood agar and incubated for 24 hours at 37° C. Then, we cultivated it on 21 blood agar plates. We randomly put one chlorhexidine disk on 10 plates and one fluorin total disk on other 10 plates. We also placed antibiogram disk and a blank disk without mouthwash on 1 plate. We placed the plates at 37° C for 24 to 48 hours into the incubator and then measured the growth inhibition zone.
The growth inhibition zone in the chlorhexidine and fluorin total group was 15.4 mm and 11.4 mm, respectively, which was 4mm higher in the chlorhexidine group,which is statistically significant.
Due to the complications of chlorhexidine mouthwash, this mouthwash cannot be used on a daily basis. It seems that fluorin total mouthwash can be used as an auxiliary method for those who are at high risk of decay.

Denture induced stomatitis occurs in 24-60 percents of edentulous people who have dentures.Up to now some etiologic factors have been introduced for denture stomatitis but there are some controversies.In some literatures some other microorganisms have been isolated besides candida albicans as main reasons. According to the incidence of denture induced stomatitis and the resistance and recurrence to treatment with antifungal drugs in some of these cases
this research was done to evaluate the role of actinomycets in these lesions In this case control study the samples were collected from15 persons with removable full dentures without any denture stomatitis and 15 persons with removable full dentures with denture stomatitis lesions. Both groups were matched according to age, gender،duration of denture wearing، systemic diseases ,oral hygine, smoking,xerostomia,use of medicines and The samples were transported to the lab in thyo culture and incubated in  37 C for 1 week and then transported to Brain and Heart infusion culture .After sample processing for microscopic evaluation for detecting actinomycets ،the results were  analyzed with chi-square test by using spss soft ware version14. The results shows that 5 of 15 (33.3%)  in control group and 11 of 15 (73.3%) in case group  were actinomycets positive. (p <0.03) It seems that, actinomycets can play a role in denture stomatitis، besides candida albicans.

The most frequent cause of TMJ dysfunction is internal derangement which that largely involves  the function of the articular disc. Anterior disc displacement (ADD) is one of the major findings in TMJ internal derangement.
Since the importance of knowledge of its etiology and also The role of all structural indicators association with TMD was not evaluated, in this research was investigated Correlation between  TMJ structure and disc displacement. This study was done based on case-control method. 31 Joints  with TMJ internal derangements and 57 normal joint Were examined. The two groups of clients were matched in age, sex , Economic and social situation. MRI finding was Disk position in Open and closed mouth and  condyle morphology coronal and axial view.MRI findings were Disk position in Open and closed mouth and  condyle morphology coronal and axial view. The data were analyzed using  x2 and Fisher's test. Patients with  TMJ internal derangement (ID), In all three groups  inchiding disk displacement with reduction(DDWR), disk displacement without reduction(DDWOR), anterior disc displacement(ADD), was encountered more frequently in Anterior, Anterior-inferior disk position in closed mouth,A statistically significant correlation was found( P 0.001> ). Also no significant difference was found in measurements between the three groups, for condyle morphology  in coronal and axial view. ( P > 0.4) It seems there is relationship between Anterior disc displacement (ADD) and Anterior, Anterior-inferior disk position in closed. But There is no obvious relationship between Anterior disc displacement (ADD)  And  condyle morphology coronal and axial view.

Using fluoridated toothpaste is one of the effective preventive methods of dental caries. The aim of this study was to evaluate the total and soluble fluoride concentration in different toothpastes available in the Iranian market. In this study, total and soluble fluoride concentration of eight brands of Iranian and five brands of non-Iranian toothpastes were measured. The samples were extracted from top and bottom end of each tube. Then they were mixed until homogenous suspension was achieved. Total and soluble concentration of fluoride ion was measured by potentiometer. To compare results of total and soluble fluoride concentration in the top and bottom of each tube and results between domestic and foreign toothpastes, the Mann-Whitney test was used. A total of 13 toothpastes were tested, of which five products were for children and eight products were for adults. Eleven toothpastes had Sodium Monofluorophosphate agent.
Among adult toothpastes, only ABC and Signal toothpastes had international standard range of fluoride concentration and the total fluoride concentration was near to the amount printed on the tube.
Bass, Ferris, Goldent and Komodo Iranian Children toothpastes showed higher concentration of total fluoride compare to international standard range of fluoride for children. None of Iranian children toothpastes had the total fluoride concentration same as what printed on the tube. More serious supervision and accurate quality control on the concentration of fluoride in toothpastes is required, especially in Children toothpastes, it should be paid more attention. If soluble fluoride concentration is printed on toothpaste tube, it helps to select the right toothpaste.

 The purpose of this study was to investigate the effect of an educational intervention - course of "smoking and oral health"- on knowledge and attitude of dental students about the complications of smoking and the role of the dentist in smoking cessation.  A quasi-experimental study was conducted on 62 dental students from Isfahan University of Medical Sciences as control group, and 63 dental students from Isfahan Azad University as experimental group. Volunteer students filled out a self-administered questionnaire about their knowledge and attitude regarding dentist’s role in smoking cessation. During the ongoing semester, educational intervention was conducted. Then, the students filled out the questionnaires again. Paired sample t-test، Independent sample t-test ، Chi square، and Fisher exact test served for statistical analysis.  Before the intervention, no significant difference existed between two groups regarding their knowledge score (P=0.46). Following the intervention however, knowledge score in intervention group was significantly higher than control group (P<0.001). Students' attitude was not significantly different between two groups before the intervention (P=0.93). Following the intervention, attitude score was significantly higher in intervention group than control group (P<0.001). Following the intervention, the mean scores of attitude increased significantly in both groups (P<0.001). However, the increased score of knowledge and attitude in intervention group was significantly higher than control group (P<0.001).   Course of “Smoking and Oral Health” improved students’ knowledge and attitudes towards smoking cessation. Although, students’ performance was not evaluated, it seems that educational programs may improve their performance as well.

 Despite the increasing number and quality of dental research, many dentists are not adequately informed about the results of the studies and don’t use it at clinic. The aim of study to evaluated obstacles in use of research results from the perspective of dental specialists of Shahid Sadoughi University of Medical Sciences in Yazd.  In this descriptive cross-sectional study, all dental specialists of the faculty member of Shahid Sadoughi University of Medical Sciences in Yazd in 2016 were studied by census method. 57 people were evaluated. Data were collected by a questionnaire,that consisted of demographic information and 22 items derived from the Funk questionnaire, measured by 5 scale Likert. Data were analyzed by SPSS 17 software and descriptive statistics.  Participation rate was 100%. Among the different domains of not being possible to use the results in the clinic, the area of communication and access to research findings with a mean and standard deviation of 21.42±3.04 and among the barriers, the lack of a plan by the relevant authorities to apply the results of the research in operation with the mean and standard deviation of 4.09±0.80 were the most important domain and most important barrier respectively.   In order to increase the application of the results of research into clinical practice, many efforts are needed to establish a systematic program with continuous follow up by relevant authorities and to increase the scientific ability and confidence among professors, dental students and graduates of this field.

Giant cell Granulomas (central and peripheral) are two fairly common lesions of the oral cavity with uncertain etiology and pathogenesis. As well, the reason for their different biologic behavior is not well understood yet. This study aimed to review the immunohistochemical profile of giant cell granuloma and its correlation with pathogenesis and biologic behavior. The articles in scientific databases including Google Scholar, PubMed, and ScienceDirect published between 2010 to April 2019, were searched by using relevant keywords including giant cell granuloma, pathogenesis, and biologic behavior. Twenty seven articles which used immunohistochemistry technique were reviewed regarding immunoexpression of protein in different type of cells, difference of expression between groups, correlation between expression of the marker and biologic behavior and pathogenesis. According to the findings of the reviewed studies, angiogenic markers had positive relation with behavior and pathogenesis in 55.5% and 33.3% of the studies, respectively. Review of the proteins related to osteoclastogenesis demonstrated that 45.4% and 77.2% of the studied proteins had positive relation with behavior and pathogenesis, respectively. Regarding the cell cycle proteins, 42.8% and 57.1% of the articles showed positive and negative correlation with biologic behavior, respectively. However, 85.7% of the studies observed no obvious correlation with pathogenesis. It seems that osteoclastogenesis and the related proteins and its signaling pathways has the greatest correlation with pathogenesis. In addition, the most relevant factor to biologic behavior was angiogenesis.