Journal of Research in Dental Sciences
Year:2014 | Volume:11 | Issue:1 (39)|Papers Count:9

Background and Aim: One of the adverse effects of acidic whitening materials is salivary pH changes of the oral cavity and the resultant damage to tooth structure. The concern for potential side effects is greater when OTC bleaching products are used without consultation of a dental professional. The purpose of this in vivo study was to evaluate the effect of bleaching strips on salivary pH of dental students (in vivo).Materials and Methods: This experimental in vivo research was done on 20 dental students aged 20-24 years old. All subjects signed a consent form before participating in the study. Students' unstimulated salivary pH was measured by saliva- check kit (GC, USA). Bleaching strips (crest advanced vivid white strip, USA) containing 9.5% hydrogen peroxide were applied to the surface of six anterior maxillary teeth for 14 days (30 minutes daily) according to the manufacturer's instructions. Salivary pH was measured on first, seventh and fourteenth day of the treatment. Measurements were taken 10 minutes, 20 minutes, and 30 minutes into the treatment as well as 30 minutes following treatment completion. Statistical analysis was done by Friedman and Kruskal-Wallis tests.Results: A statistically insignificant decline in salivary pH level was seen 10 minutes into the procedure on first, seventh and 14th day of the treatment (p<0.2). Salivary pH value returned to baseline 30-60 min after initiation of treatment. The difference in baseline and final pH value (upon completion of treatment) was not statistically significant (P>0.05).Conclusion: Based on the results of this study, bleaching strips containing 9.5% hydrogen peroxide have no effect on salivary pH.

Background and Aim: The present study compared antibacterial efficacy of sodium diclofenac, sodium diclofenac+streptomycin, tri-antibiotic and calcium hydroxide on enterococcus faecalis biofilm.Materials and Methods: In this in vitro trial, enterococcus faecalis was cultured on blood agar plate overnight. Colonies from this culture were suspended in 10 ml of normal saline solution and the resulting bacterial suspension turbidity was adjusted to McFarland standard (108 CFU/ml). E. faecalis biofilm was dispensed on 56 sterile cellulose nitrate filter disks 13mm in diameter, 0.2 micron in thickness. The disks were placed on blood agar plates and incubated anaerobically for 48 hours at 37’C. After incubation, the disks were introduced to antibacterial agents. Buffered saline was used to wash out the disks five times in order to terminate the antibacterial activity of the agents. The colony-forming units of the remaining viable bacteria on the disks were calculated. Statistical analysis was done using Kruskal-Wallis and Mann-Whitney U tests.Results: Tri-antibiotic and streptomycin completely removed enterococcus faecalis strains from the culture. The next highest antibacterial activity was found in modified tri-antibiotic, diclofenac in combination with streptomycin, diclofenac alone, and calcium hydroxide (mean CFU: 135.8, 160.67, 207, and 794.5 respectively; p<0.004). The use of streptomycin with sodium diclofenac improved the antibacterial efficacy (p<0.004) while replacement of the sodium diclofenac with minocycline in tri-antibiotic drug significantly decreased the antibacterial activity of the agent (p<0.002).Conclusion: Antibacterial properties of sodium diclofenac against enterococcus faecalis biofilm were was significantly higher than calcium hydroxide. Its use may be feasible as an alternative to calcium hydroxide in root canal therapy.

Background and Aim: Tissue conditioners are used to manage irritation of denture bearing mucosa. These liners, however, promote adherence and colonization by Candida Albicans which can be prevented by incorporating antifungal agents into them. The aim of this in vitro study was to assess the stability and duration of antifungal effects of nystatin and fluconazole mixed with a tissue conditioner on colonization of Candida Albicans.Materials and Methods: In this experimental study, antifungal test disks were prepared using tissue conditioner mixed with nystatin and fluconazole. Similar drug free tissue conditioner disks were prepared as controls. The disks were immersed and kept in artificial sterile saliva until used for susceptibility test. They were placed on the Sabouraud dextrose agar plates streaked with C. Albicans inoculum and using the agar diffusion test, colonization inhibitory effects were evaluated in one, two, three and 5 day intervals based on saliva immersion period. The mean inhibitory zone around disks at different time intervals were analyzed with SPSS15 software using ANOVA and Tukey’s statistical tests for multiple and pairwise comparisons respectively.Results: The average diameter of inhibitory zone around nystatin and fluconazole disks after 24hour of immersion in saliva were 11.2 and 8.6 mm respectively. The difference in the mean zone of inhibition was statistically significant after 24 hours (p=0.0001) and 48 hours (p=0.013). This difference was not statistically significant after 72hours or 5 day interval. (P>0.05)Conclusion: The stability of nystatin and fluconazole mixed with a tissue conditioner is not adequate and antifungal effects are seen only for 72 hours while in contact with saliva. Optimum antifungal activity could be expected in the first 24 hours. Nystatin exhibits higher inhibitory effects compared to fluconazole.

Background and Aim: Dental caries is the most common cause of tooth loss and early detection of dental caries is a major step towards dental health. Carious lesions is a fundamental step in preserving dental health. Tooth decay could change tooth electrical conductivity. The porosity of the enamel tissue as well as the electrical conductivity of teeth can be altered by tooth decay. Therefore, the aim of this study was to measure the electrical resistance of teeth and its relation to the degree of dental caries.Materials and Methods: In this experimental study to investigate the structural differences in dental caries, electrical parameters such as resistance and capacitance of teeth were measured for sound enamel and dentin, superficial caries, deep caries, and extensive caries. The resistance and capacitance of teeth with various degrees of decay were compared with sound teeth. The relationship between the electrical parameters and the decay rate was evaluated using ANOVA Test.Results: The results showed that the electrical resistances changed significantly by decay (p<0.05) By increasing the depth of tooth decay, the electrical resistance decreased based on a linear relationship. It also revealed there was a significant association between capacitance and deep and superficial decay. (P=0.01) The capacitance and decay changed based on a non-linear relationship.Conclusion: Quantification of dental resistance can be a useful tool for detection of caries, and it is proposed as a method for detecting deep caries with high accuracy.

Background and Aim: Periodontal diseases are the most prevalent diseases of the oral cavity. The objective of this study was to evaluate the association between the salivary cortisol levels with moderate to severe periodontitis in patients referring to Oral Medicine Department of Dental Branch of Islamic Azad University of Tehran.Materials and Methods: This study was case control. Thirty patients with moderate to severe periodontitis were selected as case group and 30 patients were selected as control group. They answered hospital anxiety and depression scale (HAD scale) stress questionnaire. Periodontal indices such as plaque index and pocket probing depth and clinical attachment loss were assessed. Each subject provided a saliva sample of 1ml and the cortisol level was assessed by ELISA method. Both groups were matched regarding confounding variables (age, sex and smoking). Data were analyzed using chi-squared test and using Odds Ratio. Correlation between HAD scale results and salivary cortisol level was assessed using Pearson correlation test.Results: The mean age of case group was 41.77±7.92 and the mean age of control group was 40.73±7.94. Cut off point of salivary cortisol level was determined as 5.7 ng/ml by ROC curve method. There were 17 patients (56.7%) in case group and 4 in control group (13.3%) who exhibited salivary cortisol level over 5.7 ng/ml (p<0.0005). The mean of HAD scale was 14.07±6.10 in case group and 11.27±4.24 in control group.Conclusion: The results indicate that there is a significant positive association between elevated salivary cortisol levels and moderate to severe periodontitis. This finding justifies further cohort studies or clinical trials.

Background and Aim: Passive cigarette smoking or environmental tobacco smoke (ETS) exposure is a major public health concern. Children are the most vulnerable group to ETS exposure. The aim of this study was to evaluate the relationship between passive smoking and Total Antioxidant Capacity (TAC) and salivary lipid peroxidation in adolescents.Materials and Methods: In this historical cohort study sixty adolescents aged 12 to 15 years old were selected. The subjects were assigned into two groups of healthy non-smokers (control) and passive smokers (case) and they were matched for age and sex. Unstimulated saliva was collected with spiting method, and then TAC and salivary lipid peroxidation were measured with FRAP and TBARS methods respectively. Statistical analysis was done using independent t-test.Results: TAC was significantly lower in passive smokers (1218.8±511.5 mmol) than in nonsmokers (1490.5±379.2 mmol) (p=0.023). Salivary lipid peroxidation level was higher in passive smokers (14.6±0.6 mmol) than in nonsmokers (14.4±0.8 mmol) but it the difference was not statistically significant (p=0.176).Conclusions: The exposure to cigarette smoke can cause a reduction in the salivary Total Antioxidant Capacity.

Background and Aim: An accurate localization of the lowest border of the cortex of maxillary sinus floor is important to avoid injury in certain surgical procedures. The aim of this study was to evaluate and compare the accuracy of linear measurements between digital panoramic radiography and cone beam computerized tomography (CBCT) in determining the vertical distance between the alveolar crest and floor of the maxillary sinus.Material and Methods: In this descriptive study 2 cadaver’s skull were used. Thirteen areas separated by 5mm distance were selected on each skull. A total 26 reference points were marked by gutta percha cones between maxillary first premolar and second molar. Digital panoramic radiography and CBCT were obtained, after which, direct measurements were taken on sectioned skulls using a digital caliper (0.1mm accuracy). After of adjusting the radiographic values with the magnification factors given for each unit, statistical analysis was done using the Wilcoxon and signed ranks test.Results: The mean error for linear measurements was 0.36+0.34 mm in digital panoramic radiography and 0.08±0.06mm in CBCT (P=0.001). All (100%) values obtained for CBCT and 65.38% of values obtained for digital panoramic were within±0.5 mm of error limits.Conclusion: CBCT offers more accurate linear measurements to determine the vertical distance between the alveolar crest and floor of the maxillary.

Background and Aim: Esthetics is one of the prosthetic treatment goals. Correct selection of anterior teeth, regarding size and appearance, results in a successful treatment. Using the extra oral indicators is a common method to determine the size of the tooth. In this study, the correlation between the facial widths (in bizygomatic and intercondylar areas) and the mesiodistal width of maxillary central incisors was analyzed.Materials and Methods: A cross-sectional study was conducted on 100 qualified students, 50 females and 50 males. Two facial widths comprising Intercondylar width -distance between two approximately Beyron hinge axis- and bizygomatic width -two most convex points of zygomatic arch- were marked and measured by a facebow and a digital caliper. Mesiodistal maxillary central incisors’ widths were measured by a digital caliper. The collected data were analyzed via Pearson correlation coefficient.Results: The mesiodistal width of right central incisor was 8.47±0.56. The mesiodistal width of left central incisor was 8.54±0.64.The bizygomatic width was 126.15±6.74. The intercondylar width was 131.43±5.41. There was no correlation between bizygomatic width and central incisors (P>0.05) and a weak correlation between intercondylar width and central incisors in Iranian community.Conclusion: Facial width is not recommended as a suitable landmark for estimating the mesiodistal width of maxillary central incisors.

Background and Aim: Placebo analgesia has not been investigated extensively in dental settings. Using scaling and root planning (SRP) as a model, this investigation aimed at evaluating the placebo analgesia during SRP.Materials and Methods: One hundred and eighty two patients participated in this double-blind, randomized, controlled clinical trial. Having signed an informed consent form, and obtaining demographic characteristics, all the individuals filled a modified dental anxiety index questionnaire. Based on random blocks, 91 patients were given one placebo capsule 30 minutes before SRP as a potent pain killer, and 91 control subjects received SRP alone. Pain was recorded using a 10 centimeter VAS as well as a 5-point verbal Likert scale (VRS-5) during SRP for each sextant of dentition. Statistical analysis was done by chi-square, Spearman correlation coefficient, and Mann-U-Whitney tests using SPSS software version19.Results: There was no statistical difference between placebo and control groups regarding anxiety, age, sex, pocket depth, and clinical attachment level (P>0.05). VAS and VRS-5 scores were not statistically different between case and control subjects using Mann-Whitney test. Spearman rank test revealed a correlation between the two pain measuring methods (P<0.0001).Conclusion: Within the limitations of this study, the placebo medication is not capable of reducing pain during SRP. to demonstrate the real placebo analgesic effects and complete the results of the present study, more investigations with control of confounding variables are suggested.