مجله دندانپزشکی دانشگاه علوم پزشکی تهران
سال بیست و هشتم شماره 1 (پیاپی 82، بهار 1394)

The routine mechanical plaque control is done by toothbrush. With regard to different designs of tooth head brushes in order to better plaque removal، the aim of this study was to evaluate the effect of between teeth and cross-action tooth brush on the plaque and gingival status among dental students of dental branch-Islamic Azad University during 2012-13 academic years. This single-blind، cross over، clinical trial was conducted on 30 subjects with mean age (23±0. 9) in two groups of 15 persons. They had at least 20 teeth and had gingivitis with no history of antibiotic use in the last 3 months. Those who were undergoing orthodontic treatment، using drugs affecting the gums and having crown and bridge were excluded from the study. The first group used the cross action toothbrush and the second group used between teeth toothbrush and the subjects were asked to brush their teeth for two minutes twice a day in modified bass method and not to floss during the execution of this study. After 14 days plaque index (Turesky، Approximal plaque index) and gingival bleeding index were recorded on all teeth except third molars. After a week wash out period، second stage of the study was conducted the same as the first stage with the other kind of brush for each group. Data were analyzed using Generalized Linear Model (GLM) test. There was no statistical significant difference between two toothbrushes based on plaque index، gingival bleeding index and approximal plaque index، respectively (P = 0. 29، P = 0. 47، P = 0. 33). In all measured indices، the treatment sequence showed no significant difference (P = 0. 23). There was no statistical difference between cross-action and between teeth toothbrush in reducing plaque and gingival bleeding.

Nowadays patients refer to orthodontist for issue such as dental crowding and other aesthetic problems. The aims of this study were to evaluate the relationship between some of mandibular anatomical landmarks and dental crowding in the patient with skeletal Cl II due to mandibular deficiency. 108 cases have been randomly selected out of patients with mandibular related Cl II problem associated with lower incisor crowding، out of orthodontic patient department of Tehran university of medical sciences. ANB، SNB، mandibular discrepancy، gonial angle، Sn-Go-Gn and IMPA was evaluated out of the data. Lateral cephalograms were used for this matter. The correlation between variables was evaluated by correlation test and after reviewing the data was analyzed using Normality test، the Pearson correlation coefficient was used for normally distributed variables. Corpus-ramus length ratio had a significant relationship with dental crowding (P≤0. 05) but there was no meaningful and significant relationship between other facial landmarks (P = 0. 26). there seems to be a slight relationship between facial landmarks and dental crowding in lower incisors. But further case control and clinical studies may be helpful in achieving more reliable data.

The aim of this review article was to define the mechanism of action and effects of commonly used medications on the tissue remodeling and Orthodontic Tooth Movement (OTM). A review on the effects of medications and dietary supplements on the rate of experimental tooth movement was performed using Cochrane library، Embase and medline (1980-2013). 63 articles were included in this review. 34 of them were related to the effects of hormones and analgesics، were evaluated in this article but their interpretation was hindered by the variability in experimental design، magnitude of force applied during tooth movement and medication regimens. Non Steroidal Anti-Inflammatory Drugs (NSAIDs) reduced the rate of tooth movement while non-NSAIDs such as acetaminophen had no effect on the rate of OTM. Corticosteroids، parathyroid hormone and thyroxin increased the rate of tooth movement. Sturgeons might slow OTM، but experimental studies are lacking. Medications might have an important influence on the rate of tooth movement and information on their consumption is necessary to adequately discuss treatment planning with patients.

Marginal fit is one of the key factors in the success of fixed restoration. The aim of this study was to evaluate the fitness of feldespatic crowns made from additional silicon impression and gypsum cast by CAD/CAM. 10 intact extracted upper premolar teeth were used for this experimental study. After preparation of the mounted teeth with radial shoulder finish line، 2 Vita Mark II feldespatic CAD/CAM machined crowns were fabricated for each tooth (one from scanning the additional silicone impression of the prepared tooth and the other one from the plaster model). Marginal gap of each crown was measured using SEM in two points on the mesial and 2 points on the buccal surface. Data were analyzed using Paired t-test with SPSS version 17 software (P<0. 05). The mean of marginal gaps in crowns fabricated from additional silicone and model plaster were (155. 13±37. 11) and (130. 18±12. 35)، respectively. However، no significant difference emerged between marginal gaps of the two methods (P=0. 055). Also، the mean of marginal gaps in crowns fabricated from additional silicone and model plaster was higher in mesial (157. 82±44. 41) compared to buccal (127. 50±24. 26) region (P=0. 003). Marginal fit was not significantly differen ce between crown s made of the plaster casts and silicone molds and both methods showed the same results.

Porcelain restorations are often ground for clinical adjustment and this removes the surface glaze layer and introduces flaws that can grow in wet environments due to stress-corrosion، reduce the strength of porcelain and limit restoration lifetime. The aim of this study was to introduce some surface treatment methods to control the flaws of ceramic restorations external surface and improve their strength.

40 feldspathic discs were prepared and divided into 4 groups (n=10): not indented (group 1) and others indented by vickers with 29. 4 N and received different treatments: no treatment (group 2)، polished (group 3) and polished-silane-resin (group 4). Biaxial flexural strength of discs was tested after water storage. Data were analyzed using one-way ANOVA.

The mean flexural strength of specimens in group 1 (134. 49±12. 60)، 2 (94. 81±15. 41)، 3 (89. 20±16. 22) and 4 (80. 67±12. 01) were measured. Group 1 (not indented) revealed significantly higher strength (P<0. 001) than that of indented groups (2، 3 and 4). There was no significant difference between group 2 (no treatment) and 3 or 4 (treated) and between treatment methods (3 and 4) (P=0. 136).

The strength of porcelains is dependent on presence of cracks. With the limitations of this study، none of the treatment methods could strengthen the cracked ceramic.

To ensure root canal treatment success، endodontic microbiota should be efficiently reduced. Several irrigation devices have been recently introduced with the main objective of improving root canal disinfection. The purpose of this study was to evaluate the rinsing effect of RinsEndo system in reduction of enterococcus faecalis in comparison with conventional hand syringe in infected root canals. 60 extracted single canal anterior teeth were infected with enterococcus faecalis and divided into 3 groups: RinsEndo system، conventional hand syringe and control group. The enterococcus faecalis colonies were counted in each group before and after rinsing. Data were analyzed using Variance and Kruskal Wallis test. The mean of enterococcus faecalis growth after rinsing was 3. 50×103 in group with conventional syring rinsing، 2. 04×103 in group with RinsEndo washing and 6. 11×103 in control group. Reduction of enterococcus faecalis after rinsing was statistically significant in each group (P<0. 001). The amount of reduction in number of colonies with RinsEndo and conventional syringe rinsing was higher in comparison with control group and this difference was significant (P<0. 001). RinsEndo rinsing effect was statistically significantly higher in comparison to conventional syringe as well (P<0. 001). Rinsing with RinsEndo system was significantly more efficient in reduction of enterococcus faecalis from root canal in comparison with hand syringe washing.

Posterior palatal seal is one of the most important areas to support maxillary complete denture. The aims of this study was to evaluate the dimensional accuracy of both direct and indirect relining methods on the maxillary posterior palatal seal area. A maxillary edentulous model was selected. A 1. 5 mm layer of wax was placed on the model to create a space for relining material and impression was done by the silicone material and 20 casts was prepared. By putting the wax on the casts and performed of flasking، 20 dentures were prepared. Direct reline method (as Chair side with GC reline) and indirect method (with Acrosoft-TC and firing with Acropars 100) were evaluated. The relined bases were put on the model and the spaces between them in five points (two points on the ridge، two points in the deepest part of palate and one point in the middle of palate) were calculated by the Stereo microscope and each calculations was repeated 5 times and the mean dimensional changes was measured. To compare the groups، data were analyzed using multivariate analysis. The gap of P. P. S area was between 740. 86 and 2356. 49. Direct method (1011. 81±60. 56) had a lesser gap in comparison with indirect (2056. 8±13. 13)، and both method showed a significant statistic variance (P<0. 0001). Direct method showed a lesser gap in comparison with indirect method. By direct method adaptation of the denture in the P. P. S area would be better.

An attractive، well-balanced smile is a paramount treatment objective of the modern orthodontic therapy. The purpose of this study was to determine the effects of the buccal corridor size and tooth-gingival display on the smile esthetics as perceived by two groups of the students. A colored image of a woman frontal posed smile was selected. The image was altered digitally to produce different buccal corridor sizes (6%، 12. 5% and 20%) and different tooth-gingival displays (maxillary central incisors and 2 mm of gingival، maxillary central incisors and dental papilla and 80% of the maxillary central incisors). The different buccal corridor sizes and tooth-gingival displays were combined to produce 9 images. These altered images were rated by 120 medical and dental students using Visual Analogue Scale (VAS). Data were analyzed using Mann-Whitney test، Pairwise comparison LSD test، Repeated measure MANOVA and ICC (Intraclass Correlation Coefficient). The smile which had the buccal corridor size of 12. 5% and complete incisor display without gingival display received the highest rates among the nine smile images in the dental students group. But in the medical students group the smile with the buccal corridor size of 12. 5% and 2 mm gingival display، received the highest rates among the nine smile images. There was no significant difference in judging between the male and female raters for the both groups (P>0. 05). The dental students were more critical about the increasing of the gingival display. In the treatment procedure that may lead to the combination of wide buccal corridor and more tooth-gingival show، more caution should be considered.

Aesthetic and smile design is one of the most important motivations for going to dentists and one of the most of researchers’ attention. The most important aspect of the remedy is to diagnose، especially when aesthetic is concerned and dentist should interfere the patient actively in the treatment planning. It means dentist must know what is aesthetic in patient points of view. One way to achieve this goal is digital imaging، patients images taken by digital intra oral cameras transfer to the computer and some changes done on their primary images and define all possible looks and at the end، all these looks must be shown to the patient by dentist and decide for the true remedy plan. This article introduced the software، which has prepared this aim that is easy to use and has no expense.