Comparison of occlusal bite force distribution in subjects with different occlusal characteristics.

OBJECTIVE: To analyze bite force distribution in subjects with different occlusal characteristics. METHODS: This prospective study included 132 candidates (50 males, 82 females) seeking orthodontic treatment, who were divided into four groups based on Angle's classification of malocclusion. T-Scan® III Version 7.0 was used to record their relative distribution of bite forces, which were compared using gender, Angle's occlusal classification, overjet, overbite, space analysis, sagittal, and transverse skeletal relations variables. RESULTS: ANOVA revealed significant differences in posterior/anterior bite force ratios between sagittal dental and skeletal relationships, overjet, and overbite groups (p < 0.05). No significant difference was found between different space analysis and transverse relationship groups (p > 0.05) or between genders (p > 0.05). CONCLUSION: Subjects with Class III, decreased overjet and decreased overbite displayed higher bite force in posterior teeth compared to other groups. This feature must be considered when evaluating patients with dental and periodontal pathologies that might be affected by excessive tooth stress, especially in subjects with oral parafunctions and bruxism.

Morphological features of Class I, II and III malocclusions of Saudi adolescents.

AIMS: This cross-sectional study compared and contrasted the morphological characteristics of Class I, II and III malocclusions in an adolescent Saudi population. METHODS: Adolescent Saudis with Angle's Class I, II and III malocclusions were selected from orthodontic patients' records. Angular and linear measurements were compared between the three groups. Cephalometric analysis was performed using the VistadentOC® software. Multifactorial ANOVA for angular and linear measurements between and within groups. RESULTS: Orthodontic records of 300 patients were included. There was no significant difference between and within groups in age and distribution of Angle's classification, p > 0.05. Multifactorial ANOVA showed that there were significant interactions between gender and malocclusions in skeletal, dental and soft tissue measurements, p < 0.05. There were significant differences in the sagittal and vertical skeletal measurements between groups, p < 0.05. The dental measurements were also significantly different in most of the measurements (p < 0.05). Moreover, there were significantly different readings among the groups in the soft tissue analysis. CONCLUSION: Morphological characteristics of adolescent Saudis show unique differences between gender and malocclusions, more so in Class III malocclusions. Class II and III malocclusions also show skeletal differences amongst the groups.

Occlusion time, occlusal balance and lateral occlusal scheme in subjects with various dental and skeletal characteristics: A prospective clinical study.

OBJECTIVES: To analyse occlusion time, occlusal balance and lateral occlusal scheme in subjects with various dental and skeletal characteristics. METHODS: A total of 132 subjects (50 males and 82 females) seeking orthodontic treatment were included in this prospective study. Using the T-Scan III version 7.0 (Tekscan Inc, South Boston, MA, USA), the occlusion time, occlusal balance and lateral occlusal schemes were recorded and compared with gender, Angle's occlusal classification, overjet, overbite, space analysis, skeletal and transverse relations. ANOVA, t test and contingency tables analyses were performed. Statistical significance was set at P < .05. RESULTS: Occlusion time was significantly shorter in subjects with balanced occlusion (0.18 seconds, P < .001), Class I normal occlusion (0.35 seconds, P = .028) and Class I skeletal profile (0.37 seconds, P = .002). Occlusion time was significantly longer in subjects with decreased overjet (0.60 seconds, P = .003). There were significant associations between the distribution of occlusal balance and Angles' classes of occlusion, skeletal relationship, overjet, overbite and space analysis (P < .05). Lateral occlusal schemes were only associated with Angle's classes of occlusion and skeletal relationship (P < .05). CONCLUSIONS: Patients with Class I occlusion showed the least occlusion time, the most balanced occlusion and a higher frequency of canine guidance. Nonetheless, potentially balanced occlusion and group function were highly prevalent in all groups; therefore, ideal occlusion must be considered an ideal to inspire and aim for, but cannot be considered an essential requirement of every dental treatment.

OC-STAMP promotes osteoclast fusion for pathogenic bone resorption in periodontitis via up-regulation of permissive fusogen CD9.

Cell fusion-mediated formation of multinuclear osteoclasts (OCs) plays a key role in bone resorption. It is reported that 2 unique OC-specific fusogens [ i.e., OC-stimulatory transmembrane protein (OC-STAMP) and dendritic cell-specific transmembrane protein (DC-STAMP)], and permissive fusogen CD9, are involved in OC fusion. In contrast to DC-STAMP-knockout (KO) mice, which show the osteopetrotic phenotype, OC-STAMP-KO mice show no difference in systemic bone mineral density. Nonetheless, according to the ligature-induced periodontitis model, significantly lower level of bone resorption was found in OC-STAMP-KO mice compared to WT mice. Anti-OC-STAMP-neutralizing mAb down-modulated in vitro: 1) the emergence of large multinuclear tartrate-resistant acid phosphatase-positive cells, 2) pit formation, and 3) mRNA and protein expression of CD9, but not DC-STAMP, in receptor activator of NF-κB ligand (RANKL)-stimulated OC precursor cells (OCps). While anti-DC-STAMP-mAb also down-regulated RANKL-induced osteoclastogenesis in vitro, it had no effect on CD9 expression. In our mouse model, systemic administration of anti-OC-STAMP-mAb suppressed the expression of CD9 mRNA, but not DC-STAMP mRNA, in periodontal tissue, along with diminished alveolar bone loss and reduced emergence of CD9+ OCps and tartrate-resistant acid phosphatase-positive multinuclear OCs. The present study demonstrated that OC-STAMP partners CD9 to promote periodontal bone destruction by up-regulation of fusion during osteoclastogenesis, suggesting that anti-OC-STAMP-mAb may lead to the development of a novel therapeutic regimen for periodontitis.-Ishii, T., Ruiz-Torruella, M., Ikeda, A., Shindo, S., Movila, A., Mawardi, H., Albassam, A., Kayal, R. A., Al-Dharrab, A. A., Egashira, K., Wisitrasameewong, W., Yamamoto, K., Mira, A. I., Sueishi, K., Han, X., Taubman, M. A., Miyamoto, T., Kawai, T. OC-STAMP promotes osteoclast fusion for pathogenic bone resorption in periodontitis via up-regulation of permissive fusogen CD9.

Zein based magnesium oxide nanoparticles: Assessment of antimicrobial activity for dental implications.

MgO nanoparticles have been recently discovered as an antibacterial, however, they limited by property degradation due to agglomeration. The addition of a coating agent, such as a zein polymer, is effective in preventing agglomeration without affecting nanosized properties. The aim of this study was to assess the antimicrobial property of MgO nanoparticles when coated with a zein polymer against several oral bacteria and fungi. This was done by utilizing various assessment techniques. The ultimate aim is to use these nanoparticles in dental preparations. The antimicrobial activity of zein-coated MgO nanoparticles at different concentrations of 0.5, 1 and 2% were tested against four different microorganisms: Staphylococcus aureus, Streptococcus mutans and Enterococcus faecalis (gram positive bacteria), and Candida albicans (as oral fungus). Two different techniques were utilized: the Kirby-Bauer test, and a modified direct contact test. The results indicated that the antibacterial effect of 1% or 2% zein-coated MgO nanowires were statistically significant (p<0.05) against the four organisms studied: S. mutans, S. aureus, E. faecalis and C. albicans. Zein-coated MgO nanoparticles are a new human friendly and potent antimicrobial agent that can be incorporated in the formulation of a variety of new dental materials and products that should provide improvements in dental care and oral health.

Three-year Prospective Evaluation of Immediately Loaded Mandibular Implant Overdentures retained with Locator Attachments.

INTRODUCTION: Immediate implant-loading protocol has progressed because of various clinical advantages offered by this treatment approach. However, available studies on edentulous patients are still few compared to those in which delayed implant-loading protocol was applied. AIM: This prospective study was to evaluate the implant survival rate and the peri-implant tissue response in a group of patients who received two unsplinted immediately loaded dental implants in the mandibular anterior region to retain a complete overdenture using locator attachments. MATERIALS AND METHODS: A total of 24 edentulous patients with a mean age of 63.4 years were involved in this study following certain inclusion criteria. All patients received a new set of complete dentures before implant positioning. Two Prima Connex tapered implants were put in the interforaminal area of the mandible with a flapless surgical procedure, and the prefabricated dentures were immediately retained with a zest locator attachment. Clinical and radiographic records of the patients were reviewed immediately after placement of the implant, at 3 months, and at 1, 2, and 3 years following fixture installation. The obtained data were analyzed using paired samples t-test and the Wilcoxon signed-rank test at 0.05 significance level. RESULTS: At 3 years, all implants had osseointegrated with a 100% survival rate. In addition, the total mean marginal bone change was -0.89 ± 0.14 mm, and the mean periotest value was -7.631 ± 0.921. CONCLUSION: Results of this study propose that immediate loading of mandibular implant overdentures that are retained with locator attachments was a feasible treatment alternative for this particular group of patients. CLINICAL SIGNIFICANCE: Immediate implant- loading of mandibular implant overdentures that are retained with locator attachments is a reliable treatment option Keywords: Immediate implant loading, Implant survival rate, Locator attachments, Overdenture.

Radiographic evaluation of dental age maturity in 3-17-years-old saudi children as an indicator of chronological age.

OBJECTIVE: This study was aimed to evaluate the dental age in Saudi children from panoramic radiographs using the Demirjian method to estimate their chronological age. MATERIALS AND METHODS: This retrospective cross-sectional study consisted of 1902 panoramic radiographs of 955 boys and 947 girls between the ages of 3-17 years. All children were placed in the age group closest to their chronological age. The dental age was scored on all seven left mandibular teeth by calibrated examiners. Bivariate analyses using the t-test and Pearson correlation were performed. RESULTS: There was significant difference in both boys and girls in all the age groups between their chronological age and dental age. Even though there was a slight overestimation in boys in some age groups and slight underestimation in girls in some groups, correlation analysis showed that there was a highly significant correlation between the chronological age and dental age for both boys (r2 = 0.96, P < 0.001) and girls (r2 = 0.98, P < 0.001). Moreover, correlation analyses for each age group showed a significant correlation between the chronological age and the dental age, using the Demirjian method, in most age groups (P < 0.01). When comparing the maturation score between boys and girls, the Student's t-test showed that there were no statistical differences between boys and girls in most age groups. CONCLUSION: Saudi boys and girls living in the western region of Saudi Arabia exhibited similar pattern of dental development when compared to the Demirjian method. Hence, the Demirjian method could be used as reference in children from the western region of Saudi Arabia.

Phosphoglycerol dihydroceramide, a distinctive ceramide produced by Porphyromonas gingivalis, promotes RANKL-induced osteoclastogenesis by acting on non-muscle myosin II-A (Myh9), an osteoclast cell fusion regulatory factor.

Among several virulence factors produced by the periodontal pathogen Porphyromonas gingivalis (Pg), a recently identified novel class of dihydroceramide lipids that contains a long acyl-chain has the potential to play a pathogenic role in periodontitis because of its higher level of tissue penetration compared to other lipid classes produced by Pg. However, the possible impact of Pg ceramides on osteoclastogenesis is largely unknown. In the present study, we report that the phosphoglycerol dihydroceramide (PGDHC) isolated from Pg enhanced osteoclastogenesis in vitro and in vivo. Using RAW264.7 cells, in vitro assays indicated that PGDHC can promote RANKL-induced osteoclastogenesis by generating remarkably larger TRAP+ multinuclear osteoclasts compared to Pg LPS in a TLR2/4-independent manner. According to fluorescent confocal microscopy, co-localization of non-muscle myosin II-A (Myh9) and PGDHC was observed in the cytoplasm of osteoclasts, indicating the membrane-permeability of PGDHC. Loss- and gain-of-function assays using RNAi-based Myh9 gene silencing, as well as overexpression of the Myh9 gene, in RAW264.7 cells showed that interaction of PGDHC with Myh9 enhances RANKL-induced osteoclastogenesis. It was also demonstrated that PGDHC can upregulate the expression of dendritic cell-specific transmembrane protein (DC-STAMP), an important osteoclast fusogen, through signaling that involves Rac1, suggesting that interaction of PGDHC with Myh9 can elicit the cell signal that promotes osteoclast cell fusion. Taken together, our data indicated that PGDHC is a Pg-derived, cell-permeable ceramide that possesses a unique property of promoting osteoclastogenesis via interaction with Myh9 which, in turn, activates a Rac1/DC-STAMP pathway for upregulation of osteoclast cell fusion.

Evaluation of root canal transportation, centering ratio, and remaining dentin thickness of TRUShape and ProTaper Next systems in curved root canals using micro-computed tomography.

OBJECTIVE: To evaluate and compare the volume of removed dentin, transportation, and centering ability of TRUShape (TRS; Dentsply Tulsa Dental Specialties) system with ProTaper Next (PTN; Dentsply Maillefer) by using micro-computed tomography (µCT). METHOD AND MATERIALS: Twenty extracted human mandibular first molars with two separate mesial canals with curvatures of 25 to 35 degrees were divided into two experimental groups (n = 20) according to the rotary nickel-titanium file system used in canal instrumentation as follows: group TRS and group PTN. Canals were scanned before and after instrumentation using µCT to evaluate root canal transportation, centering ratio, and volumetric changes. Data of canal transportation and centering ratio values were analyzed using independent t test. Volume changes data were statistically analyzed using Mann-Whitney test. Statistical significance level was set at P < .05. RESULTS: The PTN group had a significantly lower mean volume of removed dentin (2.09 ±â€¯0.41 mm3) than the TRS group (2.77 ±â€¯0.72 mm3) (P < .05). At the coronal level, there was no significant difference in canal transportation (P = .170) and centering ratio (P = .111) between TRS and PTN groups. However, at the apical and middle levels, the PTN group had a significantly lower mean transportation value and higher centering ratio than the TRS group (P < .05). CONCLUSION: Root canal preparation with the PTN system revealed better performance with fewer canal aberrations than the TRS system in curved root canals.

A randomized cross over study comparing the efficacy of two mandibular advancement appliances in the treatment of mild-moderate obstructive sleep apnea.

OBJECTIVE: To compare efficacy, side effects, patient compliance, and preference between two types of custom-made mandibular advancement appliances (MAAs) in the treatment of patients with mild to moderate obstructive sleep apnea (OSA). METHODOLOGY: This prospective, randomized, crossover study of 12 patients with mild to moderate OSA compared a titratable and a non-titratable MAA. Each patient was fitted with both appliances in a random order with a washout period of two weeks. Efficacy, side effects, compliance, and preference were evaluated by a questionnaire. All patients underwent overnight home sleep recordings prior to and after the use of each appliance in order to objectively assess sleep quality in terms of the apnea and hypopnea index (AHI), snoring frequency and oxygen desaturation index. RESULTS: Treatment successes (relief of symptoms and/or reduction of AHI to <10/h) were reported with both types of appliances. No compliance failure was reported, and in most patients, the side effects were mild, and improved with time. CONCLUSION: Both types of oral appliances were effective treatments for patients with mild to moderate OSA, with fewer side effects and higher patient satisfaction.

A novel method of sampling gingival crevicular fluid from a mouse model of periodontitis.

Using a mouse model of silk ligature-induced periodontal disease (PD), we report a novel method of sampling mouse gingival crevicular fluid (GCF) to evaluate the time-dependent secretion patterns of bone resorption-related cytokines. GCF is a serum transudate containing host-derived biomarkers which can represent cellular response in the periodontium. As such, human clinical evaluations of PD status rely on sampling this critical secretion. At the same time, a method of sampling GCF from mice is absent, hindering the translational value of mouse models of PD. Therefore, we herein report a novel method of sampling GCF from a mouse model of periodontitis, involving a series of easy steps. First, the original ligature used for induction of PD was removed, and a fresh ligature for sampling GCF was placed in the gingival crevice for 10min. Immediately afterwards, the volume of GCF collected in the sampling ligature was measured using a high precision weighing balance. The sampling ligature containing GCF was then immersed in a solution of PBS-Tween 20 and subjected to ELISA. This enabled us to monitor the volume of GCF and detect time-dependent changes in the expression of such cytokines as IL-1b, TNF-α, IL-6, RANKL, and OPG associated with the levels of alveolar bone loss, as reflected in GCF collected from a mouse model of PD. Therefore, this novel GCF sampling method can be used to measure various cytokines in GCF relative to the dynamic changes in periodontal bone loss induced in a mouse model of PD.

TRAP-positive osteoclast precursors mediate ROS/NO-dependent bactericidal activity via TLR4.

Osteoclastogenesis was induced by RANKL stimulation in mouse monocytes to examine the possible bactericidal function of osteoclast precursors (OCp) and mature osteoclasts (OCm) relative to their production of NO and ROS. Tartrate-resistant acid phosphatase (TRAP)-positive OCp, but few or no OCm, phagocytized and killed Escherichia coli in association with the production of reactive oxygen species (ROS) and nitric oxide (NO). Phagocytosis of E. coli and production of ROS and NO were significantly lower in TRAP+ OCp derived from Toll-like receptor (TLR)-4 KO mice than that derived from wild-type (WT) or TLR2-KO mice. Interestingly, after phagocytosis, TRAP+ OCp derived from wild-type and TLR2-KO mice did not differentiate into OCm, even with continuous exposure to RANKL. In contrast, E. coli-phagocytized TRAP+ OCp from TLR4-KO mice could differentiate into OCm. Importantly, neither NO nor ROS produced by TRAP+ OCp appeared to be engaged in phagocytosis-induced suppression of osteoclastogenesis. These results suggested that TLR4 signaling not only induces ROS and NO production to kill phagocytized bacteria, but also interrupts OCm differentiation. Thus, it can be concluded that TRAP+ OCp, but not OCm, can mediate bactericidal activity via phagocytosis accompanied by the production of ROS and NO via TLR4-associated reprograming toward phagocytic cell type.

Thermogravimetric Characterization of the Microstructui Composition of Polyamide Injection Molded Denture Base Material vs Conventional Compression Molded Heat-cured Denture Base Material.

BACKGROUND: Thermoplastic resin polymers are widely used in medicine due to their biostability and hypoallergenic properties, making them a possible alternative to poly-methylmethacrylate (PMMA). The current research examined the microstructure of a rapid injection molding system thermoplastic resin for construction of flexible denture compared with that of heat-cured PMMA. MATERIALS AND METHODS: A total of 40 disk-shaped specimens (25 mm in diameter and 3 mm in thickness) were prepared and divided into two groups of 20 disks each (group I samples were of thermoplastic acrylic resin while group II was heat-cured PMMA resin). RESULTS: In group I, thermogravimetric analyzer showed that increasing the temperature up to 169°C resulted in about 1.3% of the material loss, and after that the material remains thermally stable up to 200°C. Group 11 showed 2.24% weight loss at 171°C, and further weight loss (12.025%) was observed on heating to 230°C. Fourier transform infrared (FTIR) spectrophotometer analysis in the range of 400-4000 cm(-1) detected the presence of an amine group (N-H) in group I samples and the presence of methylene group attached to inorganic Si as reinforcement filler (Si-CH3). CONCLUSION: Thermoplastic resin displayed excellent thermal stability and the absence of residual monomer within the polymerized material, suggesting its suitability for the fabrication dentures.

Influence of denture adhesives on occlusion and disocclusion times.

STATEMENT OF PROBLEM: The effectiveness of adhesives in enhancing several functional aspects of complete denture performance has been well established. The direct influence of adhesives on occlusal contact simultaneity has not yet been investigated. PURPOSE: The purpose of this crossover clinical trial was to evaluate quantitatively the influence of adhesives on occlusal balance by recording timed occlusal contacts; namely occlusion time (OT) and disocclusion time during right (DT-right) and left (DT-left) excursions by using computerized occlusal analysis. MATERIAL AND METHODS: A crossover clinical trial was adopted. Assessments were carried out while participants (n=49) wore their dentures first without then with adhesives. Computerized occlusal analysis using the T-Scan III system was conducted to perform baseline computer-guided occlusal adjustment for conventionally fabricated dentures. Retention and stability assessment using the modified Kapur index and recording of OT and DT-right and DT-left values using the T-Scan III were subsequently carried out for all dentures, first without adhesives and then after application of adhesive. All T-Scan procedures were carried out by the same clinician. Wilcoxon signed-rank test was used to analyze the Kapur index scores and occlusal parameters (α=.05). RESULTS: Stability and retention of conventional dentures ranged initially from good to very good. However, adhesive application resulted in significant improvement (P<.001) in stability and retention and a significant decrease in duration of all occlusal parameters (OT [P=.003], DT-right [P=.003], and DT-left [P=.008]). CONCLUSIONS: Adhesives significantly decreased OT and DT durations in initially well-fitting complete dentures with fairly well balanced occlusion, and further enhanced denture stability and occlusal contact simultaneity.

Reliability of didactic grades to predict practical skills in an undergraduate dental college in Saudi Arabia.

OBJECTIVES: This longitudinal study was aimed to investigate the association between didactic grades and practical skills for dental students and whether didactic grades can reliability predict the dental students' practical performance. MATERIALS AND METHODS: Didactic and practical grades for graduates from the Faculty of Dentistry, King Abdulaziz University, between the years 2009 and 2011 were collected. Four courses were selected: Dental Anatomy, Operative Dentistry, Prosthodontics, and Orthodontics. Pearson product-moment correlation analyses between didactic and practical scores were conducted. RESULTS: There was only a significant correlation between didactic and practical scores for the Dental Anatomy course (P<0.001). There was also a significant correlation between all four subjects in the didactic scores (P<0.001). Only the scores of male students showed a significant correlation in the Operative Dentistry course (P<0.001). There were no correlations between Orthodontic grades. Moreover, a poor degree of reliability was found between didactic and practical scores for all subjects. CONCLUSION: Based on the findings of this study, the relationship between didactic grades and practical performance is course specific. Didactic grades do not reliably predict the students' practical skills. Measuring practical performances should be independent from didactic grading.

Surface roughness and internal porosity of partial removable dental prosthesis frameworks fabricated from conventional wax and light-polymerized patterns: a comparative study.

STATEMENT OF PROBLEM: Surface roughness and internal porosity are 2 potential risk factors that threaten the biocompatibility and long-term mechanical stability of cast partial removable dental prostheses frameworks. PURPOSE: The purpose of this study was to investigate the influence of the material, of conventional wax patterns, and the recently introduced light-polymerized patterns on the initial surface roughness and internal porosity of the cobalt-chromium castings of partial removable dental prostheses. MATERIAL AND METHODS: Twenty-eight identical partial removable dental prosthesis frameworks were fabricated on a cast of a maxillary Kennedy Class III modification 1 partially edentulous patient. Fourteen frameworks were fabricated from each pattern material. The initial surface roughness, Ra (µm), of the resultant castings was measured with a profilometer. Radiographs of the castings were made on dental occlusal films with a dental x-ray unit with the following exposure conditions: tube voltage 70 kV; exposure time 1.0 seconds; tube current 7 mA; and source-film distance 35 cm. The number and size of porosities in the 3 main components (clasp units, major connectors, denture base meshwork) were assessed. Statistical analysis was conducted with the independent sample t test for surface roughness and the Mann Whitney test for internal porosity (α=.05). RESULTS: The statistical analysis of mean surface roughness and internal porosity revealed no significant difference between the 2 groups. CONCLUSIONS: The surface roughness and internal porosity of frameworks fabricated from conventional wax and Liwa patterns were comparable, with no significant differences between the 2 pattern materials.

Effect of energy drinks on the color stability of nanofilled composite resin.

OBJECTIVE: To study the effect of three energy drinks on the color stability of nanofilled composite resins after different periods of aging time. MATERIALS AND METHODS: Composite resin disks, 6 mm diameter, 3 mm thickness were prepared from Filtec Z350 XT, Tetric EvoCeram, and Filtec Z250 XT. Specimens from each material were tested after aging with Red Bull, Bison and Power Horse energy drinks and distilled water as a control. Specimens were stored at 37°C in dark containers for 1, 7, 30 and 60 days. Color was assessed in the CIELAB using a colorimeter before and after each storage period. Color differences ΔE*ab and Δb* among specimens were measured. Mean values were statistically analyzed using one-way analysis of variance (ANOVA), with p < 0.05 as significance level. RESULTS: The color change ΔE*ab and Δb* occurred by Red Bull, Bison and Power Horse energy drinks was significantly different for all tested materials at all four times p < 0.05 except in the Red Bull group. All specimens showed increase in color changes toward yellowness Δb* after a period of 1, 7, 30 and 60 days. The highest total color difference ΔE*ab was found in the Red Bull group after 60 days. CONCLUSION: Energy drinks used in this study had staining effect on the tested composite resin materials. The discoloration increased with aging time toward yellowness; however, it was not perceptible in all test groups after 60 days.

Correlation of psychomotor skills and didactic performance among dental students in Saudi Arabia.

OBJECTIVES: The objective of this study is to investigate the correlation between the psychomotor skills and the academic performance of dental students. METHODS: Didactic and preclinical scores were collected for students who graduated from the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia, in 2011. Three courses (Dental Anatomy, Removable Prosthodontic Denture, and Orthodontics) were selected. Correlations comparing didactic and practical scores were done for the total samples, then for the males and females separately. RESULTS: There was no significant correlation between the practical and didactic scores for the three courses for the total sample. There was a significant correlation between all three subjects in the didactic scores. For females, the results showed that there was only a significant correlation between the practical and didactic scores for Dental Anatomy. For males, no correlation was observed between the practical and didactic scores for all subjects. CONCLUSION: In the present sample, didactic performance did not correlate well with the students' psychomotor performance.

The effect of different storage conditions on the physical properties of pigmented medical grade I silicone maxillofacial material.

Objective. This study aimed to evaluate the effect of different storage solutions that simulate acidic, alkaline, and sebum conditiions on the physical properties of pigmented (colorant elastomer) cosmesil M511 maxillofacial prosthetic material. Materials and Methods. Sixty specimens were prepared according to the manufacturer's instructions and were tested before and after immersion of different storage conditions for six months at 37 °C. The following tests were performed: color changes (group I), solution absorption (group II), surface roughness (group III), and scanning electron microscopy (group IV). Results. There were no significant changes observed in the color and solution absorption tests while surface roughness revealed significant difference between control group and other testing storage medium groups, and this result was supported by SEM analysis that revealed limited surface changes. Conclusions. Cosmaseil material is an acceptable cross-linked formulation that withstands storage in different solutions with variable pH. The addition of pigment cannot vary the physical properties of these materials. Surface roughness test as well as SEM microscopic study showed moderate changes indicating a limited effect on the surface of the material.

Assessment of hepatitis B vaccination and compliance with infection control among dentists in Saudi Arabia.

OBJECTIVE: To evaluate hepatitis B virus (HBV) vaccine coverage and the use of infection control among dentists in Saudi Arabia. METHODS: This cross-sectional study was carried out during the Third International Conference at the King Abdulaziz University Faculty of Dentistry, held on March 2012 in Jeddah, Saudi Arabia. Saudi or expatriate dentists working in Saudi Arabia were included in the study. The questionnaires were designed to meet the objective of the study. RESULTS: A total of 402 dentists of whom 176 (44%) were male and 226 (56%) female took part in this study. Their mean age was 37.4 years. In all, 246 (61%) were general dentists and 156 (39%) specialists. Four-fifths (80.5%) of them had been vaccinated. Almost half (48.5%) had experience of needle stick injury, but none reported having been infected with HBV. Among the vaccinated dentists, 186 (57.5%) had not been screened for HBV antibodies. Younger dentists were more particular about vaccination and more careful in using protective wear. There was an association between protective barriers and HBV vaccination, but there was no association between history of needle stick injury and vaccination. CONCLUSION: Dental healthcare workers have a high risk of infection with HBV due to the nature of their work; so there should be a mandatory program to vaccinate dentists against HBV and to ensure application of protective measures during their practice.