Journal of Islamic Dental Association of IRAN
Volume:27 Issue: 2, 2015

Complete denture’s retention is an important issue which sometimes in spite of all efforts does not provide patient and dentist’s satisfaction. The aim of this study was to evaluate the effect of sandblasting the impression surface on the maxillary denture retention. In this Before and After Clinical trial, for 15 patient of the Department of Prosthodontics of the Shahed University, 2 bases similar to their original upper denture were prepared. By applying a digital force transducer, the force needed to dislodge the base from the patients’ palate was measured. The internal surface of the bases were air abraded by 50 micron Alumina particles for 1 minute except for the borders which were covered by Aluminum thin foils. By sandblasting, the mean retention of the bases increased from 30.89± 10.74 N to 37.66±9.76 N (21.9%) which was statistically significant (p<0.0001). According to the findings of the present study, sandblasting the intaglio surface of the maxillary complete denture with abrasive particles will enhance the retention of the denture.

Intracanal medicaments can affect the bond strength of composite to dentine. The aim of this study was to evaluate the effect of 2% chlorhexidine (CHX) gel as an intracanal medicament on shear bond strength of three different composite resins to dentin. In this in-vitro study, 60 intact extracted human premolars were utilized. Each tooth was sectioned vertically and dentin of the buccal surface was exposed. Then, specimens were divided into six groups of 10 teeth. In groups 1-3, dentin was exposed to CHX and in groups 4-6, dentin was exposed to saline. All prepared surfaces were rinsed with distilled water and dentin bonding agent specific for each composite was applied on the dentin surfaces. Z100, Z350 and P90 composites were applied to the treated surfaces and cured. The shear bond strength was recorded in Newtons and converted to MPa. Data were analyzed using the Kruskal-Wallis and MannWhitney U tests. The lowest mean shear bond strength was reported for normal saline and Z100 composite group (18.47 MPa) and the highest for CHX and Z350 group (42.26 MPa). No statistically significant difference in bond strength values was found between normal saline and CHX groups (p>0.05). There was a significant difference in bond strength values of different composite resins in normal saline (p<0.05) and also in CHX groups (p<0.05). chlorhexidine gel 2% slightly but not significantly increases the mean shear bond strength of composite to dentin. The type of composite influences the shear bond strength to dentin.

Some researchers have attempted to enhance the antibacterial properties of sealers byaddition of antibiotics while this may affect their physical properties.The purpose of this in vitro study was to comparethe working time and flow of AH Plus sealer alone and in combination with amoxicillin and triple antibiotic paste (TAP). This in vitro study assessed the flow and working time of AH Plus alone (control group) and in combination with amoxicillin and TAP in 1%, 5%, 10% and 25%concentrationsaccording to ANSI/ADA specification NO. 57. The data were analyzed by ANOVA and Tukey’s test. Statistically significant differences were noted in the flow and working time of control group with those of different concentrations of TAP in combination with sealer (p<0.0001).). The working time decreased by an increase inthe concentration of TAP. The AH Plus/ 1% TAP and AH Plus/5% TAP showed higher flow than the control group. The AH plus /1% amoxicillin, AH Plus/5% amoxicillinand AH Plus/10% TAPhad a flow similar to that of the control group. Other groups showed lower flow than the control group. All the alterations in the physical properties of AH Plus sealer in combination with amoxicillin and TAPwere within the ANSI/ADA specification NO 57 standard range.

Lichen planus (LP) is a chronic mucocutaneous disorder mediated by the impaired immunity, in which the concomitance of clinical and histopathological findings are necessary for a definite diagnosis. In case of discrepancy between clinical and histopathological findings, use of adjunct diagnostic methods such as direct immunofluorescence (DIF) is recommended. This study sought to assess the repeatability of clinico-histopathological findings and direct immunofluorescence of fixed, paraffin embedded specimens for diagnosis of LP. In this retrospective descriptive study, 49 oral and cutaneous LP specimens were subjected to DIF assessment using fibrinogen, C3 and IgM. The intensity of fluorescence staining was graded as 0, 1 or 2. Findings were compared in each group and between oral and cutaneous LP groups using statistical tests. Statistical analyses revealed a correlation between C3 and IgM expression (Spearman’s rho: 0.697, p=0.000), which was more prominent in cutaneous specimens (p=0.000). Additionally, a correlation was observed between fibrinogen and IgM expression in oral LP (Spearman’s rho: 0.764, p=0.02). It seems that DIF assessment of formalin-fixed, paraffin embedded specimens using C3, fibrinogen and IgM does not have adequate repeatability for clinico-histopathological findings; although, combined application of C3 and IgM in cutaneous and IgM and fibrinogen in oral LP specimens showed higher repeatability.

The retromolar canal is an anatomical structure of the mandible and a type of bifid inferior alveolar canal. The retromolar canal might conduct accessory innervation to the mandibular molars or contain an aberrant buccal nerve; thus, this canal is of clinical significance. The aim of this study was to evaluate the prevalence of retromolar canal on cone-beam computed tomography (CBCT) scans. In this descriptive-analytical study, 151 retromolar canalsin 102 patients (102 unilateral and 49 bilateral) with third molar teethrequiring CBCT were evaluated. The scans were evaluated for presence of the retromolar canal and linear measurements (distance to second molar, height and width) were made. The data were analyzed by independent t-test and chi square test. The prevalence of retromolar canal was 7.3% (n=11).With regard to linear measurements, the mean distance from the retromolar canal to the second molar was 12.76± 4.3mm. The mean height of the canal was 6.66 ±2.18mm, and the mean width was 1.7± 0.6mm. The presence of retromolar canal was not statistically correlated withsex, side of the jaw or age (P=0.146). The prevalence of retromolar canal on CBCT scans was 7.3%.

Bleached teeth are susceptible to discoloration. The aim of this study was to evaluate discoloration of bleached teeth following short-term use of several mouthwashes. In this In-vitro experimental study, 48 extracted maxillary central incisorswere selected and divided into four groups of 12. All the teeth were subjected to external bleaching with 38% hydrogen peroxide (H2O2). After bleaching, the teeth were immersed in in distilled water (control group or group 1), chlorhexidine (CHX; group 2), Irsha (group 3) or Persica (group 4) for three, seven and 14 days. The color change was assessed by a spectrophotometer at each time point and reported as 6E1, 6E2 and 6E3. The results were analyzed by paired t-test, repeated measures ANOVA, one-way ANOVA and LSD test. Different mouthwashes (p=0.043) and immersion times (p=0.038) caused significantly variable color change in bleached teeth. After 14 days of immersion, the color change of samples in Persica group had significant differences with that of other groups (p<0.000). The results of repeated measures ANOVA was only significant for the Persica group indicating significant color change over time. Thus, paired t-test was applied for pairwise comparison of the time points, which revealed significant differences between 6E1 and 6E3 and also 6E2 and 6E3 (p<0.05). Persica mouthwash would cause significant discoloration in recently bleached teeth.

Mutans streptococci are the main cause of tooth decay. Application of natural materials as mouthwash has been effective in reducing the bacterial count. This study aimed to assess the antimicrobial effects of rose water and pomegranate vinegar in comparison with Persica mouthwash on two oral bacteria responsible for tooth decay. Strongly adherent strains of Streptococcus mutans and Streptococcus sobrinus were selected for this in vitro study. Antimicrobial effects of pomegranate vinegar and rose water on microbial count in the biofilm and adhesion potential of bacteria was evaluated by microtiter plate method. Also, the well-plate technique was used to assess the effect of rose water and pomegranate vinegar in comparison with Persica mouthwash on bacterial growth and proliferation. The obtained resulted were analyzed by one-way ANOVA and Tukey’s post hoc test using Graph Pad Prism version 5 software. Level of significance was set at P=0.05 with 95% confidence interval. Pomegranate vinegar, rose water and Persica decreased plaque formation by S. mutans by 93%, 80% and 68%, respectively. These values for the S. sobrinus were 92%, 57% and 48%, respectively (all Ps<0.001). Pomegranate vinegar was more effective than the other two materials (p<0.001). However, none of these materials eliminated the biofilm. Pomegranate vinegar and Persica mouthwash had a negative effect on growth of the aforementioned bacteria. Within the limitations of this study, it seems that pomegranate vinegar and rose water have the potential to prevent or control the proliferation of S. mutans and S. sobrinus.

Advances in information and communication technology have had a great impact on people’s lives. Beside all the benefits, they have caused some problems such as digital divide. This study aimed to assess the digital divide among the faculty members of dental prosthetics departments in dental schools of medical universities in Tehran in 2014. This applied research had a descriptive analytical designand was conducted through a survey analysis. The statistical population of this study consisted of all the faculty members of dental prosthetics departments in dental schools of medical universities in Tehran (n=100). Data werecollected using a researcher-designed questionnaire; its validity was confirmed by an expert panel and its reliability (3 = 0.978) was confirmed using Cronbach’s alpha test. The data were analyzed using SPSS version 22 and t-test, ANOVA, Chi-square test and the Pearson’s correlation test. A total of 82 questionnaires were filled out and returned by the faculty members.The results showed that 97.5% of the study population had access to computers at home and at work; 96.3% had Internet access at home and 97.5% had access to Internet at work; 51.9% (n=42) of the faculty members used these technologies several times a day; 29.6% (highest frequency) reported average daily use ofthese technologiesto be half an hour to an hour. Marital status and academicrankinghad significant effects on the skills of using information and communication technologies. Age and years of instructionwere also effective on technology literacy, the ability and skills to use information and communication technologies and the requirements to use these technologies. Based on the results, marital status, academic ranking, age and years of instruction are effective in use of information and communication technologies by the faculty members.