Journal of Dental Medicine

Background and Aims: Despite their ascribed intellectual ability and achieved academic pursuits, the dental student’s academic achievement is influenced by learning motivation. This study in an Endeavour aimed to examine the learning motivation factors of dental students of Rafsanjan University of Medical Sciences.
Materials and Methods: In this descriptive-cross sectional study, 120 dental students completed the questionnaire which comprised of 33 questions regarding intrinsic and exogenic motivational factors. Demographic factors (gender, marital and native status, employment year of study) were examined. Data were analyzed by SPSS17 software. Descriptive and analytical statistical methods (t-test, Pearson correlation and ANOVA statistical tests) were used.
Results: The mean of the achieved scores in the domains of learning motivation was 2.98±0.32 out of 5,which was considered as moderate level. Comparing the means of the intrinsic (3.16±0.48) and exogenic
(2.82±0.44) domains showed significant differences (P<0.05). Correlation between the intrinsic motivation domain and elements of exogenic motivation domain with academic achievement were not significant (P=0.62). Total score of Intrinsic and exogenic motivation is higher in male and non-native students.
Conclusion: Educational motivation of Rafsanjan dental students was moderate. In learning, intrinsic motivational factor was more than exogenic factors in male students.

Background and Aims: Increased tooth sensitivity is a common dental problem. One of the mechanisms of dentin hypersensitivity treatment is blocking dentinal tubules. The aim of this study was to compare the average closing dentinal tubules affected by carbonated Nano-hydroxyapatite and fluoride toothpaste using scanning electron microscope (SEM).
Materials and Methods: The enamel of gingival buccal crown surfaces of 42 sound maxillary premolars teeth were removed until the dentin surfaces were exposed. The dentine specimens of 3×3 mm were prepared. The specimens were washed by distilled water after etching and randomly divided into 6 groups. 3 groups were interfered with the carbonated nano-hydroxyapatite toothpaste and the other three groups interfered with Colgate toothpaste in 3, 7 and 14 days. The samples were examined by SEM to check the status of dentinal tubules. Then, they were evaluated by two researchers according to the Hulsmann index. Data were analyzed by using SPSS23 software and Kruskal-Wallis statistical test. The significance level of 0.05 was considered.
Results: The amount of dentinal tubules closure by the two toothpastes was significantly different. This difference was higher in the hydroxyapatite toothpaste than fluoride which were (P=0.024, 0.004 and 0.000), respectively. There were no significant differences among the groups in 3,7 and 14 days (P=0.230, 0.069, 0.537).
Conclusion: The toothpaste containing carbonated nano structural hydroxyapatite was more successful in closing dentinal tubules than Colgate toothpaste in short period of time.

Background and Aims: Despite patient’s demand increased for tooth color restorations, the stable bond between dentin and composite is a challenge in dentistry. Dentin protease activation is responsible for dentin-resin bond failure. The aim of this study was to determine the best pretreatment agent to inhibit matrix metalloproteinase and increase resin-dentin bond durability.
Materials and Methods: After collecting 24 intact third molars, the dentin surfaces were exposed immediately under DEJ. After acid etching of dentin rewetting was done with CHX 2%, EDC 0.3 M for 60 and water (control group). Then the adhesive (Single bond, 3M ESPE, USA) and composite (Filtek Z250 XT, 3M ESPE, USA) were applied. 48 sectioned dentinal specimens were prepared. The specimens were divided into 3 groups. Each group was divided into 2 sub groups (n=8). In half of each group, the micro tensile bond strength test was done immediately and another part half 6 months. Then, the specimens were evaluated by stereomicroscope and SEM. Statistical analysis was performed using SPSS23 software, two-way ANOVA and multiple Tukey and T-test comparisons. P<0.05 was considered as a significant level.
Results: There were not significant differences between immediate micro tensile bond strength of CHX, EDC and control groups (P=0.97). However, there was significant differences between CHX, EDC compared with the control group (P≤0.0001). Comparison between the immediate and 6-month bond strengths in each group, only in EDC group, there was no significant after 6 months’ difference (P=0.64).
Conclusion: EDC and CHX t did not have any effect on the immediate microtensile bond strength. After 6 months, EDC prevented bond strength deterioration, but the bond strength was decreased after CHX usage.

Background and Aims: The bleaching agents can lead to color and translucency changes in composite resins. Due to the increasing use of the nano composites and the silorane-based composites, this study aimed at examining the color and translucency changes of these restorations after bleaching agents.
Materials and Methods: In this experimental - laboratory study, 198 composite discs were divided into three groups of 66 specimens using three types of composite: the microhybrid composite Z250, the nanohybrid composite Z350 and the silorane-based composite P90. After acid etching, half of the specimens in each group were covered by a resin rebounding agent. Then, the color and translucency assessment was done by reflectance spectrophotometer, using CIE LAB system. Each group was divided into three subgroups of bleaching agents: the 40% hydrogen peroxide and 20% carbamide peroxide bleaching agents and the control group. After applying bleaching agents, the final color and translucency changes were assessed. Data were analyzed using Mann Whitney and Kruskal Wallis tests.
Results: The effect of composite and bleaching agent type and bonding agent were significant (P<0.001). The color changes in the microhybrid composite were higher than nanohybrid and silorane-based composites (P<0.001) (∆E>3.3). Also, the color changes by 20% carbamide peroxide were higher than that of hydrogen peroxide and control groups (P<0.001). The results of translucency changes were generally consistent with color-change measurements (∆E>3.3).
Conclusion: According to the present study, the most color changes appeared in the microhybrid composite and by 20% carbamide peroxide bleaching agent. Rebound samples were generally less affected by bleaching agents. The least color and translucency changes were related to nanohybrid composites.

Background and Aims: Erosion is the chemical dissolution of a tooth by acid without bacterial involvement. The purpose of the current study was to investigate the effect of resin infiltration (Icon), MI paste plus, and Nd:YAG laser on the enamel microhardness.
Materials and Methods: 40 enamel samples were obtained from the third molar tooth. Primary microhardness was measured in all specimens. Then, erosion was created using hydrochloride acid on the surfaces of enamel and the microhardness values were measured. The samples were randomly divided into four groups. G1: MI paste plus, G2: MI paste plus+ Nd:YA laser, G3: ICON without etching, G4: ICON with etching. Erosion was induced again by hydrochloric acid and then subjected to thermocycling. Finally, the microhardness of the samples was measured. Statistical analysis was performed using SPSS23 software, one-way ANOVA, multiple Tukey and T-test comparisons. P<0.05 was considered as a significant level.
Results: The microhardness increased in the third stage compared to the second stage in all groups, which was statistically significant (P<0.000). Also, the comparison of the increase of microhardness among groups, except second group with the fourth group, was statistically significant.
Conclusion: All the materials used in this study significantly increased the microhardness of the eroded enamel.

Background and Aims: Some of the post-operative complications of impacted third molar surgery, one of the most prevalent surgeries in oral field, are known to be infection, erythema, trismus and pain. Antibiotic prescription to prevent post-operative infection under some particular circumstances, is acceptable but under debate considering their disadvantages. In the present study, we examined the infection rate in patients taking no or 2 types of antibiotics distinctively after impacted mandibular third molar surgery.
Materials and Methods: In this double blind clinical trial, 90 patients within the age range of 18 to 34 were dedicated to 3 groups (group 1: 2 capsules of placebo on surgery day and 1 for 4 days, group 2: Amoxicillin 500 mg every 8 hours for 5 days, group 3: Azithromycin 250 mg, 2 capsules on surgery day and 1 capsule for 4 days). All subjects were treated by a sole surgeon, protocol, surgical technique, and flap type and the same amount of osteotomy. In addition to aforesaid drugs, the patients received chlorhexidine and Gelofen 400 mg. At the day 7 postoperative, cases were examined to evaluate the infection (trismus, erythema and halitosis). Data were analysed using Chi-Square test and the groups were compared by Kruskal-Wallis test.
Results: Three signs of infection (halitosis, erythema and trismus) were compared in patients. Symptoms of halitosis and erythema were more indicated in first group, but the ultimate statistical analyses among the 3 groups from halitosis and erythema viewpoint showed no significant difference (P=0.072, P=0.149). Although, no severe trismus was reported, the most moderate trismus incidence was in group 2 and mild trismus was exhibited in group 1. In group 3, no trismus occurred. On the whole, the trismus frequency among groups was statistically significant (P=0.004).
Conclusion: Comparing infection symptoms of the three study groups emphasized the fact that only trismus rate was statistically significant (P=0.004). On balance, the results of this study indicated that antibiotics did not have significant impact on the reduction of most postoperative complications, especially on infection.

Background and Aims: Adding nanoparticles to dental composite resins, could reduce bacterial adhesion and secondary caries. Thermocycling can resemble in-vitro conditions to the oral environment. The aim of this study was to determine the effect of thermocycling on the microleakage of a mixture of copper oxide nanoparticles and flowable composite.
Materials and Methods: In this in-vitro study, 88 premolar teeth were divided into eight groups based on the application of copper oxide nanoparticles with concentrations of 0.1% and 0.3% w/w and thermocycling by 0, 1000, 5000 and 15,000 cycles. The occlusal grooves of the teeth were sealed with the mixture of flowable composite and copper oxide nanoparticles, and the teeth were thermocycled. Next, the teeth were immersed in methylene blue 2% solution for 24 hrs and were cut and the microleakage was evaluated by a stereomicroscope (hp/USA). Data were analyzed using Kruskal-Wallis and Mann-Whitney tests at the significance level of 0.05.
Results: In the groups with 0.1 % copper oxide nanoparticles, the mean microleakage increased significantly with increasing the number of thermocycling rounds (P=0.032). The difference in the microleakage between the groups exposed to 0 and 15,000 termocycling was significant (P=0.019). However, thermocycling had no significant effect on the microleakage of groups with concentration of 0.3% (P=0.780). The specimens subjected to the 0, 1000, 5000 and 15000 thermocycling in two concentrations of copper oxide nanoparticles showed no significant difference in the microleakage.
Conclusion: In groups containing copper oxide nanoparticles with a concentration of 0.1%, the microleakage increased by increasing the number of thermocycling up to 15,000 cycles compared to the control group. However, this did not have significant effect for the concentration of 0.3% copper oxide nanoparticles.

Conclusion: The high prevalence of TMD and related factors, such as a history of jaw dislocation, posterior edentulousness, earache, and clenching, requires attention to be identified and treat these problems.

Background and Aims: Finishing and polishing of composites is a critical step influencing the clinical service of restorations. The aim of this article was to evaluate and compare the effect of two liquid polishes on the polish retention of two nanocomposites.
Materials and Methods: Eighty standardized disk-shaped specimens (4×2 mm) were prepared from two nanocomposites (n=40), including one nano-filled composite (Filtek Z350 XT-3M ESPE, USA) and one nano-hybrid composite (Aelite Aesthetic Enamel-Bisco, Inc. Schaumburg, USA). The specimens were randomly divided into 4 subgroups (n=10) based on the method of finishing (F) and polishing (P) procedures: M: as control, polymerized under Mylar strip; S: finish and polish with a sequence of Sof-Lex discs (3M ESPE, USA); SP: finish and polish with Sof-Lex discs and use of Permaseal liquid polish (Ultradent products, Inc. USA); SB: finish and polish with Sof-Lex discs and use of Biscover liquid polish (Bisco, Inc. Schaumburg, USA). The specimens were undergone pH cycling and brushing machine and then, the average surface roughness (Ra) and average profile changes along the desired area (Rz) of the specimens were determined with profilometer instrument. Two-way and one-way analysis of variance (ANOVA) was used to compare the mean of surface roughness. Then, Tukey test was used to identify the groups responsible for the difference and t-test was used to compare the mean of surface roughness.
Results: The type of composite and the method of polishing procedure had no effect on the mean Ra (P=0.733) but it had significant effect on Rz1 factor (P=0.025).
Conclusion: Using liquid polish after polishing discs had no effect on the polish retention of nanocomposites.

Background and Aims: The aim of this study was development and validation of a questionnaire measuring the pseudo-scientific unsupported of Iranians’ belief regarding oral health.
Materials and Methods: A list of 169 pseudo-scientific and invalid Iranian beliefs about oral health that was collected in the previous phase of the study were sent to a purposive sample of 13 professors at Mashhad dental school which resulted in extracting 34 beliefs being considered more common among Iranians. A list of 21 pseudo-scientific beliefs was obtained for preparing the questionnaire after receiving the sample opinions of 21 professors of Mashhad dental school about the invalidity and pseudoscientific propositions and their written revision. Finally, the questionnaire was completed by 44 participants to analyze the ease and clarity and to calculate Cronbach's alpha and Kuder Richardson measure as a homogeneity reliability index. It was completed in a group of 15 participants with a time interval of one month for test-retest analysis and consistency reliability evaluation.
Results: A questionnaire consisting of 21 beliefs was developed using four-point, three-point, or two-point Likert scales. The standardized Cronbach's alpha score and Kuder Richardson's measure score were 0.641 and 0.514, respectively, which indicated the moderate to good reliability of the homogeneity. The Interclass Correlation Coefficient (ICC) was calculated as 0.863, representing very good reliability of consistency of the questionnaire. Furthermore, the kappa coefficient of each of the 21 statements had a significant difference with zero (P<0.05) ranging between 0.605 and 1.
Conclusion: The result of the present study is a questionnaire measuring the level of Iranians’ belief in unsupported and invalid statements about oral health. Using this questionnaire would be helpful for dentists and oral health professionals to promote knowledge of Iranians about oral health.

Background and Aims: With the growth of elderly population, attention to their oral health status has become increasingly important. Most of the available studies have been conducted among dependent elders who usually have different oral health statuses and needs. Therefore, the aim of this study was to determine the oral health status of independent elderly attending municipal public centers and parks in Isfahan in 2020.
Materials and Methods: This is a descriptive-analytical cross-sectional study conducted among 195 elderly people attending Isfahan municipal centers in 2020. The oral health status and the oral health related quality of life (QOL) of elderly were evaluated using Geriatric Oral Health Assessment Index (GOHAI) and clinical examinations. The obtained data were analyzed using descriptive statistics (mean and standard deviation), correlation, independent T-test, Chi-squared and ANOVA using SPSS22 (α=0.05).
Results: 69% of the participants (n=133) were male and the mean age was 68.9± 3.5. Almost 20% of elderly (n=39) did not have any of their natural teeth. 63% (n=123) suffered from at least two chronic diseases and 38.5% (n=75) had a functional occlusion. The mean score of quality of life (QOL) of elderly and their DMFT was 51.7±6.4 and 20.5±6.3, respectively. A significant and negative relationship was found between the DMFT and GOHAI (P<0.001, r=-0.36). QOL scores were significantly higher in participants with dentures than those without dentures (P<0.001). There was a significant relationship between the frequency of brushing and the mean of DMFT (P<0.001). In people who did not brush, the DMFT score was higher than those who brushed at least once a day or even sometimes a week.
Conclusion: The results indicated that the oral health status of elderly was weak and it would reflect the need for more attention to taking more measures to both prevent the oral problems and to promote oral health.

Background and Aims: Root canal treatment failures are often attributed to incomplete removal of bacteria, particularly Enterococcus faecalis. While, chlorhexidine and sodium hypochlorite serve as conventional treatments. herbal medicine has been today considered as an alternative to synthetic medicine due to its safety. Therefore, the aim of the present study was to compare the antibactrial effect of Scrophularia Striata extract with chlorhexidine and sodium hypochlorite on Enterococcus Faecalis in the tooth root canal. Materials and Methods: In this study, sixty extracted teeth were examined. Following the infection of dental canals with Enterococcus faecalis, materials were tested in 3 groups: 1) chlorhexidine 2% (18 teeth), 2) sodium hypochlorite 2.5% (18 teeth), and 3) Scrophularia striata (at the concentration obtained from MIC, 20%; 18 teeth). Additionally, the positive control and negative control were included (3 teeth in each group). Samples were then cultured on bile esculin agar. After 72 hours, black colonies were eaxamined. Chi-squared test was used to analyze the results. Results: Enterococcus faecalis bacteria grew in 6, 8, and 17 out of the 18 teeth within the sodium hypochlorite, chlorhexidine, and Scrophularia striata extract groups, respectively. Consequently, the bactericidal effects for sodium hypochlorite, chlorhexidine, and Scrophularia striata extract were 66.6%, 55.5%, and 5.55%, respectively.

Conclusion: The antibacterial effect of the Scrophularia striata extract was significantly lower than chlorhexidine and sodium hypochlorite on Enterococcus faecalis in dental canals viewed as a suitable replacement to the already in use synthetic therapeutic irrigants.