Journal of Research in Dental and Maxillofacial Sciences
Volume:1 Issue: 1, Winter 2016

Evidence-Based Dentistry (EBD) is very limitedly known in Iran, and has been defined as an approach to oral healthcare that requires the judicious integration of systemic assessments of clinically relevant scientific evidences, related to patient’s history and oral and medical conditions, with dentist’s clinical expertise and patient’s treatment needs and preferences. (1-5) The EBD is a popular medical field worldwide, involving the utilization of the results of clinical dental research that improves decision-making procedures to render the best treatment available to patients, determining the highest-quality treatment methods. (6, 7)

Due to the increasing use of restorative materials, finding a suitable material with low adhesion rate and colonization of pathogenic Streptococcus mutans has a significant importance. The purpose of this study was the comparison of the adhesion rate of Streptococcus mutans to “Nano-hybrid composite” and “Amalgam” at 1, 3, and 7 day intervals. In this experimental study, 72 samples of Amalgam and composite resin were placed in two equal groups and exposed to bacterial suspension holding 1× 106 cell/ml and after three time periods of 1, 3, and 7 days, the restorative material samples were suspended in 1cc of physiologic serum, and 100µl of the suspension was cultured on Blood Agar medium. After 48 hours the number of Streptococcus mutans colonies were counted. The data were analyzed by T-test. The mean and standard deviation of Streptococcus mutans colonies adhered to Nano-hybrid composite resin at 1, 3, and 7 day intervals were measured 12.7±2.3, 1.5±2.12 and zero colonies, respectively. Adherence of Streptococcus mutans to composite resin during these three days, showed a significant statistical difference (p<0.005). The mean and standard deviation of colonies, which adhered to Amalgam at 1, 3 and 7 day intervals were 32±7.01, 18.8±3.8 and zero colonies, correspondingly. The adherence of Streptococcus mutans to Amalgam during these three days showed a significant statistical difference (p<0.001). The comparison between Amalgam and composite resin showed that the adherence of Streptococcus mutans to composite resin was lower during the first and the third day and the results were statistically significant (p<0.001). The result of this study showed that adhesion of Streptococcus mutans to Nano-hybrid composite is lower than the adhension to Amalgam.

One of the major problems with resin composite restorations is the weakness of bonding between the new and aged composites. Since appropriate micromechanical retention is necessary for the repair of aged resin composite restorations, the level of surface roughness after sandblasting can be influential in this regard. Considering the diverse composition of available resin composites in the market, the present study was performed to compare the impact of four resin composite types: Micro-hybrid (Z250), Nano-fill (Z350XT), Nano-hybrid (Z250XT) and Silorane-base (p90) on the repaired bond strength and surface roughness after sandblasting.  In this in-vitro experimental study, 44 resin composite discs with the diameter of 6mm and height of 2mm were divided to 4 groups of Micro-hybrid, Nano-fill, Nano-hybrid and Silorane-base and from 11 samples of each resin composite type, one sample was evaluated for surface roughness level before and after sandblasting with Atomic Force Microscope (AFM) and 10 samples were tested for shear bond strength in universal testing machine. The findings indicated that Micro-hybrid resin composite had the highest shear bond strength (37.8±6.4 MPa) followed respectively by Nano-fill (30 ±3.8 MPa), Silorane-base (17.9±4 MPa) and Nano-hybrid composites (7.6±1.9 MPa). The differences between all groups were significant (p <0.000).
Before sandblasting, Nano-hybrid type had the highest level of surface roughness (505 ±154nm) and the lowest value was related to Micro-hybrid resin composite (94±35nm) (p<0.000). After sandblasting, Nano-fill (1997±288nm), Silorane-base, Micro-hybrid and Nano-hybrid composites (1284 ± 645nm) showed the highest increase in surface roughness, respectively (p<0.4). In the present study, sandblasting caused a significant increase in the surface roughness of the four studied resin composite types. Despite the lowest surface roughness of Micro-hybrid type, it showed the highest bond strength amongst other composites after sandblasting.

Salivary gland tumors are among the pathologies in the head and neck that may be challenging in diagnosis and treatment. Most benign tumors occur in the parotid gland. Pleomorphic Adenoma is the most common type. Basal Cell Adenoma is a subtype of the Monomorphic Adenoma with rare occurrence. Proper diagnosis and clinical evaluation by the use of radiography can lead the physician to the best treatment plan for this neoplasia. Many surgical treatment modalities have been described in the literature ranging from total parotidectomy to dissection of the tumoral area alone. Extensive surgery will lead to malfunction and unacceptable esthetics due to resection of the parotid gland. One of the best approaches for treating the encapsulated and well-circumscribed pathologies is extra-capsular dissection without invading the major salivary gland. A rare case of Basal Cell Adenoma of the parotid gland in a 47-year-old female will be discussed.

The aim of the present study was to evaluate the cephalometric changes in Class II division 1 mandibular deficient patients treated with Farmand functional appliance.  Twenty-seven subjects (17 girls and 10 boys) with the mean age of 11.1±1.4 years were involved in the present study. All the subjects were treated with Farmand functional appliance. Paired t-test and Wilcoxon test were used to evaluate the data. The significance level was set at P<0.005. A skeletal Class I relationship and a marked reduction in the overjet were achieved with the use of Farmand appliance. ANB decreased significantly by 3.2±1.7 degrees, while SNB increased from 74.3 ±1.7 degrees to 77.6±2.3 degrees (P<0.001). The results showed that Farmand functional appliance is effective in the treatment of mandibular deficiency in patients with Class II division 1 malocclusion.

Oral mucosal lesions have various prevalence rates among different populations. Few studies have evaluated the frequency of oral mucosal lesions in Iranian population. This study aimed to determine the frequency of oral mucosal lesions and the related factors. This descriptive study was conducted based on the data in the archives of two referral centers, including the Pathology Departments of the Cancer Institute of Imam Khomeini and Buali hospitals in Tehran, from June 2000 to July 2014. Age, sex, location of the lesions and microscopic diagnosis were retrieved from the files, and the data were analyzed by SPSS13 using Chi-square test. Among 59273 files, 976 patients (1.56%) had oral mucosal lesions, and the most prevalent pathologies were epithelial lesions (89.4%), followed by connective tissue lesions (6.5%). Squamous Cell Carcinoma (53%) was the most prevalent epithelial lesion. The most common location of oral mucosal lesions was the lips (27.8%). Mean age of the patients was 44 ± 3 years. The incidence of mucosal lesions increased with age, while no correlation was observed between mucosal lesions and sex (P<0.9). The most prevalent oral mucosal lesion was the Squamous Cell Carcinoma, which is a malignant tumor with epithelial origin, and its early diagnosis is necessary.

Cone beam computed tomography (CBCT) produces high-quality data in periodontal diagnosis and treatment planning. The aim of this study was to compare the accuracy of CBCT with intraoral digital and conventional radiography in the measurement of periodontal bone defects.  In this diagnostic research, two hundred and eighteen artificial osseous defects (buccal and lingual infra-bony, inter proximal, horizontal, crater, dehiscence and fenestration defects) were shaped in 13 dry mandibles. CBCT and intraoral radiography with parallel technique by conventional film and digital sensor were compared with the standard reference (digital caliper). Inter and intra observer agreement were assessed using Intra class correlation co-efficient and Pearson correlation. Paired T-Test was applied for the comparison of absolute differences of conventional and digital intraoral radiography and CBCT measurements with the gold standard. All statistical analyses were performed using SPSS® v13.0 statistical software. Inter and intra observer agreement were both high for CBCT (ICC: α=0/88) but moderate for intraoral conventional radiography (ICC: α=0/54) and digital radiography (ICC: α=0/73). No significant differences were detected between the observers for all the techniques (P> 0.05). According to Paired T-test, mean difference for CBCT technique (0.01mm) was lower than digital radiography (0.47mm) and conventional radiography (0.63mm). CBCT allowed the measurement of all lesion types, but intraoral radiography did not allow the measurement of buccal and lingual defects. The results of this study showed that the studied radiographic modalities are useful in identifying the periodontal bone defects. CBCT technique showed the highest accuracy in the measurement of periodontal bone defects compared with digital and conventional intraoral radiography.

Considering the importance of detection of secondary caries, the adverse consequences of false positive and false negative diagnoses and the gap of information in the diagnostic efficacy of digital sensors in detection of secondary caries, this in vitro study sought to compare the diagnostic efficacy of two different resolutions of radiographs obtained by photostimulable phosphor (PSP) plate intraoral sensors in detection of secondary caries in class II composite resin restorations using a standard technique.  This diagnostic study was conducted on 40 extracted human second premolars. A classic class II cavity was prepared on one proximal surface of each tooth and restored with composite resin. Intraoral digital radiographs were obtained and saved in High and Super resolutions. Secondary caries were artificially created using a round bur mounted on a high-speed handpiece, and the teeth were radiographed again. Radiographs were saved with the mentioned two resolutions. All the radiographs were evaluated by three observers. Caries detection was classified using the yes/no dichotomous scale and data were statistically analyzed using kappa coefficient. No significant differences were found in sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of the two resolutions in caries detection (P>0.05). The High and Super resolutions of radiographs taken with digital intraoral PSP plates showed no significant differences in detection of artificially created secondary caries.