Journal of Islamic Dental Association of IRAN
Volume:26 Issue: 1, 2014

Temporomandibular joint (TMJ) dysfunction is the most common jaw disorder. TMJ imaging may be necessary to supplement information obtained from the clinical examination. The purpose of this study was to compare the diagnostic accuracy of helical computed tomography (CT) and cone beam computed tomography (CBCT) for detection of simulated mandibular condyle erosions. In this in-vitro study, simulated lesions were created in 15 dry mandibles using a dental round bur. Using CBCT and helical CT techniques, mandibular condyles were radiographed before and after creating the lesions. The images were examined by two oral and maxillofacial radiologists for absence or presence of lesions. The accuracy for detecting mandibular condyle lesions was expressed as sensitivity, specificity, positive and negative predictive values. Differences between the two radiographic modalities were analyzed by McNemar’s test. Inter-observer agreement was determined using Kappa coefficient. The maximum sensitivity, specificity and accuracy were 100%, 100% and 100% for CBCT images, respectively and 88%, 100% and 98% for helical CT images, respectively. No statistically significant difference was found between the accuracy of CBCT and helical CT for detection of mandibular condyle erosions (P = 1). CBCT is a lower-dose cost-effective alternative to helical CT for diagnostic evaluation of erosion of the mandibular condyle.

Discoloration is among the most common problems of composite restorations. Color change over time compromises the main advantage of composite resins namely their high esthetics. In such cases, the restoration needs to be replaced.. The aim of this in-vitro study was to evaluate the effect of accelerated artificial aging (AAA) on the color stability of three composite resins (Filtek Z250, Filtek Z250XT, and Filtek Supreme). In this experimental study, 7 composite specimens with equal dimensions were fabricated of each composite resin. The initial color of specimens was measured using a spectroradiometer according to the CIE L*a*b* system. The specimens were then submitted to AAA for 384h and underwent color assessment again. Before and after aging, the surface roughness of one specimen from each group was determined by Atomic Force Microscopy (AFM). The obtained color parameters were analyzed by one-way ANOVA and Tukey’s test. The color change of Filtek Z250 was significantly lower than that of Filtek Z250XT and Filtek Supreme (P≤0.05). No statistically significant differences were found between Z250XT and Supreme in this respect (P>0.05). All composite resins showed color change above the clinically acceptable threshold. Z250 microhybrid composite was more color stable than nano-composites (Z250XT and Supreme). AAA increased the surface roughness in all groups but it was within the clinically acceptable range.

An important factor in the process of diagnosis and orthodontic treatment planning is patient’s respiratory function that has a direct correlation with the upper airway size. The aim of this study was to measure and compare nasopharyngeal, oropharyngeal and hypopharyngeal airway volumes in Iranian subjects with sagittal (Class I, II and III) and vertical (normodivergent, hyperdivergent and hypodivergent) jaw discrepancies using standard cephalometric radiographs. In this descriptive cross-sectional study, 100 pre-treatment lateral cephalograms of orthodontic patients were evaluated to assess the size of upper airway space including the nasopharynx, oropharynx and hypopharynx. In order to assess airway dimensions in patients with sagittal and vertical discrepancies, subjects were divided into two large groups of normal sagittal and normal vertical patterns. Airway size was measured in sagittal plane in 50 subjects with normal vertical patterns and in vertical plane in 50 subjects with normal sagittal patterns. Linear variables i.e. the size of nasopharyngeal space (PNS-UPW), oropharyngeal space (U-MPW) and hypopharyngeal space (V-LPW) were measured by cephalometric tracing. Data were analyzed using SPSS version 15 software and chi-square, ANOVA and Tukey’s HSD tests. Understudy subjects had normal age and gender distribution pattern. In patients with normal sagittal pattern, by an increase in vertical dimension, size of nasopharynx (PNS-UPW), oropharynx (U-MPW) and hypopharynx (V-LPW) decreased and the mentioned volumes were significantly smaller in subjects with hyperdivergent facial patterns compared to hypodivergents. In subjects with normal vertical pattern, by an increase in ANB angle, size of oropharynx (U-MPW) and hypopharynx (V-LPW) decreased and the mentioned volumes in CL II patients were significantly smaller than in CL III subjects; whereas, the largest nasopharynx (PNS-UPW) was observed in CL I subjects. Sagittal and vertical discrepancies affect upper and lower airway dimensions and by an increase in facial height, the mentioned volumes decrease. Smaller ANB angle results in larger airway dimensions.

Addition of disinfectants to dental stones is one method to prevent cross-contamination between patients and laboratory personnel. This study aimed to evaluate the effect of addition of calcium hypochlorite disinfectant on setting expansion and surface hardness of dental stone. In this experimental study, calcium hypochlorite aqueous solution with 0.5% concentration was added to type V dental stone. Setting expansion was measured by extensometer in millimeter and surface hardness was measured by Rockwell hardness test machine. Data were statistically analyzed using t-test with 0.05 level of significance. The mean setting expansion values were 2.49±0.0017 mm and 0.27±0.0094 mm in the test and control groups, respectively and had a statistically significant difference. The mean Rockwell hardness number was 74±1.93 and 85±3.09 in the test and control groups, respectively with no statistically significant difference Setting expansion and surface hardness of type V dental stone increased and decreased, respectively by the addition of 0.5% calcium hypochlorite. Thus, this disinfection method needs modification for routine use in the laboratory setting.

Different medicaments are used for pain reduction following an emergency endodontic treatment. The aim of this randomized controlled clinical trial was to evaluate the analgesic efficacy of Odontopaste® and a corticosteroid-containing compound used as intracanal medicaments in between root canal therapy (RCT) appointments. In this randomized controlled clinical trial, 120 lower first and second mandibular molars with spontaneous pain and sensitivity to percussion were selected and divided into three groups of 40. After root canal preparation, patients were randomly assigned to one of the three groups. Root canals were dressed with Odontopaste in group 1, with an intracanal medicament in group 2 and with placebo in group 3. Patients determined their degree of pain intensity and percussion sensitivity on a Heft-Parker VAS diagram before the first appointment and 24 hours and 7 days post-treatment. Data were analyzed using ANOVA, Tukey’s test and Welch test. The mean spontaneous pain and percussion sensitivity scores at 24 hours after the first appointment in groups 1 and 2 were significantly lower than in group 3 (P<0.001). No statistically significant difference was found between the groups after 7 days neither in spontaneous pain nor in percussion sensitivity. Odontopaste® and the intracanal medicament caused a statistically significant reduction in postoperative

Orthodontic bracket bonding may encounter difficulties in fluorosed teeth. The aims of this study were to compare the shear bond strength (SBS) of brackets bonded to fluorosed teeth with Core Max II and Transbond XT and to assess the enamel damage after debonding. In this in-vitro study, 60 fluorosed (TFI=4 and 5) and non-fluorosed teeth were divided into two subgroups. The standard edgewise metallic brackets were bonded to the teeth with Transbond XT in the first and third groups, and with Core Max II in the remaining groups. After bonding, the SBS of the brackets was tested with a universal testing machine. The obtained data were analyzed by two-way ANOVA, post-hoc (LSD), Kruskal-Wallis, Wilcoxon, and paired samples tests. Fluorosis significantly reduced SBS (P =0.041). Core Max II significantly increased SBS (P =0.040). Teeth in group 4 (fluorosis and Transbond XT) had the lowest SBS (13.44±1.69 MPa); group 2 (fluorosis and Core Max II) showed the highest enamel damage. Core Max II is a good adhesive for orthodontic bracket bonding in fluorosed teeth but conservative debonding methods should be necessarily applied to decrease enamel damage.

Lichen planus is a common immune-mediated disease that is associated with an increased risk of malignant transformation in the oral cavity. Synchronous up-regulation of COX-2 and down-regulation of Bcl-2 have been demonstrated in some malignancies. The aim of this study was to assess the correlation between COX-2 and Bcl-2 expression and their role in dysplastic changes of oral lichen planus (OLP). This study was performed on 47 paraffin blocks with the diagnosis of OLP and 16 blocks with the diagnosis of focal fibrous hyperplasia (control group). Immunohistochemical staining was performed using antibodies against COX-2 and Bcl-2. Spearman’s rank correlation coefficient and Mann-Whitney test were used for data analysis. A significant correlation was observed between the intensity of sub-epithelial inflammation and the severity of basal cell layer degeneration (P=0.048). Significant up-regulation of Bcl-2 and COX-2 was detected in sub-epithelial inflammatory infiltration (P<0.001, P=0,003). The amount and intensity of Bcl-2 and COX-2 expression were significantly correlated in sub-epithelial lymphocytic infiltration (P=0.013, P=0.019). Our findings indicated the effective role of Bcl-2 expression in decreasing the apoptosis in the inflammator y infiltrate unlike the epithelium. The significant correlation of the intensity of Bcl-2 expression in the epithelium and the sub-epithelial inflammatory infiltrate with COX-2 expression and also the correlation of the intensity of inflammation with the severity of basal layer hydropic degeneration may imply that these two markers can induce malignant transformation in the affected epithelium in an indirect manner by the continuation of inflammation and activation of carcinogenic mechanisms.

Several techniques have been used to assess the efficacy and substantivity of mouthwashes. Considering the variability of available mouth rinses, this study aimed to assess the substantivity of several mouthwashes and their effect on microbial plaque using an epifluorescence microscope. This crossover double blind clinical trial evaluated 0.2%, and 0.12% (from 2 different brands) chlorhexidine (CHX), Persica and cetyl pyridinium chloride (CPC) mouth washes as well as normal saline as the negative control. Non-stimulated saliva samples were obtained from 16 candidates at baseline, 30s, 1, 3, 5 and 7h after one time use of mouthwashes. Epifluorescence technique was used to assess the viability of bacteria. For clinical examination following prophylaxis, subjects were asked not to use any oral hygiene measure except for the provided mouthwashes (twice a day) for 4 days. A 10-day washout period was allowed between the use of mouthwashes. Repeated measures ANOVA and Scheffe's test were applied for the comparison of viable bacterial count between the groups and Kruskal Wallis test was used for the assessment of microbial plaque. Persica and 0.12% CHX maintained their substantivity for 3 and 5h, respectively. A significant reduction in bacterial count was observed up to 7h after the use of 0.2% CHX only (P<0.001). On clinical examination, 0.2% and 0.12% CHX mouthwashes had significant differences with the others but had no significant difference with one another (P<0.02). Persica and CPC had similar efficacy (P<0.02). Efficacy of mouthwashes strongly depends on their substantivity. Daily application frequency of other mouth rinses should be increased in order to achieve an efficacy equal to that of CHX.

Advances in medical sciences have increased the volume of medical records and documents. In order to solve this problem, the information technology (IT) is now being applied to improve health care. This study aimed to assess the knowledge of dentists about IT and its application by them. In this analytical cross-sectional study, a validated questionnaire was distributed among 220 dentists participating in the 52nd International Congress of Iranian Dental Association and 120 dentists working in Tehran and included 7 questions about knowledge, 8 questions about background, 10 questions about general use of IT and 3 questions about the professional use of IT. The data were entered into SPSS version 18 software and the statistical analyses were performed by regression modeling. Of a total of 340 general practitioners, 30.4% were males and 11 dentists (3. 6%) stated that they had no access to a personal computer. Some of the most popular sites visited by dentists were Google (94.3%) and Facebook social networking site (69.8%). Among the participants, 64.5% were not familiar with any website related to their special field of work. The mean knowledge score was 5.3 (SD= 2.5). The application of professional IT was more common among men and among those with higher general use of IT. Most dentists participated in this study had insufficient knowledge about ​​ professional IT. The general and professional use of IT was poor by dentists and further instruction and training seem necessary in this respect.

Timely diagnosis is an important factor in successful treatment of diseases. In. this regard, non-invasive sampling methods such as salivary analysis may be of great help in assessment of diseases and treatment outcomes. Currently, introduction of new techniques for salivary analysis has increased its potential as a new diagnosing tool. The National Institute of Dental and Craniofacial Research (NIDCR) was the first to propose the role of saliva in diagnosis and assessment of diseases. Since then, several studies have been conducted in this respect. This review article aims to evaluate the results of these studies to provide a brief insight on the correlation of saliva with different oral and systemic diseases. Key words namely saliva, biomarkers, oral diseases and systemic diseases were searched in PubMed, Google Scholar, EBSCO, Scopus and Medline databases and articles relevant to the use of saliva for evaluation and detection of various diseases published during 1950-2011 were collected. Salivary analysis increases the collaboration between dentists and physicians and can be used for detection of some systemic conditions. This review study discusses the role of saliva in detection of different oral and systemic conditions and emphasizes its importance.