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Background: The utilization of computer-assisted designing and computer-assisted milling CAD\CAM resins in the fabrication of removable prostheses is a modern-day concept that offers many advantages over the use of the traditional polymethylmethacrylate (PMMA). Aim: This study instigated some of the mechanical properties of CAD\CAM denture base resin including the amount of residual monomer. Methods: This study was conducted at the Faculty of Dentistry, King Abdulaziz University from October 2016 to February 2017. A total of seventy rectangular specimens were fabricated (group A: 35 heat-cured PMMA and group B: 35 CAD/CAM pre-polymerized acrylic resin blocks). The flexural strength and surface hardness were tested while the residual monomer content at baseline, two-day and seven-day intervals was estimated using gas chromatography (GC). Means and standard deviations were determined for each group as well as independent- samples t-test and ANOVA with repeated measures for comparison between the groups and subgroups of varying time intervals. Results: Heat cured PMMA (A), displayed higher flexural strength and low value flexural modulus compared to CAD/CAM acrylic resin denture base material (B). Student t-test indicated highly significant differences (p

To analyze bite force distribution in subjects with different occlusal characteristics. 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. 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). 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. [ABSTRACT FROM AUTHOR]

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 ± 0.41 mm3) than the TRS group (2.77 ± 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. [ABSTRACT FROM AUTHOR]

The aim of this study was to quantify the frequency of positive radiographic findings in edentulous arches. Panoramic radiographs from 271 patients who were edentulous in one or both arches were evaluated for the presence of retained root fragments, impacted teeth, foreign bodies, radiolucencies, radiopacities, mental foramina at or near the crest of the residual alveolar ridge, and maxillary sinus proximity to the crest of the residual alveolar ridge. One or more of these radiographic observations were found in 51.7% of the examined films. The most frequent finding (30.6%) was close approximation of the maxillary sinus to the crest of the ridge. These results underscore the importance of panoramic examination of edentulous patients in detecting potential problems before complete denture treatment. However, prescribing such an examination in patients seeking replacement dentures requires a thorough patient history and clinical examination. [ABSTRACT FROM AUTHOR]

Background: The environment is often overlooked when considering dental treatment. Yet the dental environment and the interior design of a dentist's surgery may elicit a number of physiological and psychological responses in patients. This study considers the importance of the interior design of a dental surgery and the use of natural auditory stimuli to prevent the gagging reflex. Methods: This study included twenty male patients who attended the Prosthodontic clinics at King Abdulaziz University, Faculty of Dentistry (KAUFD) for help with removable dentures. During final maxillary impression making visit, the patients were split into two equal groups (group A and group B), each group consisted of ten members. Group B experienced the natural auditory stimuli whilst undergoing treatment. Group A didn't experience the stimuli. The physiological reaction of each patient within both groups was assessed by measuring the pulse rate/minutes (BPM) and arterial oxygen saturation of haemoglobin (SpO2 %). To assess the psychometric variables, patient's satisfaction levels and opinions regarding their treatment was evaluated by testing the Oral Health Impact Profile (OHIP). In addition, the patients in group B were questioned regarding how they felt after listening to the natural sounds. Results: Hearing natural sounds appeared to decrease and/or inhibit the biological stress response domains. This study revealed that patients who experienced the auditory stimulus displayed decreased heart rate and increased arterial oxygen saturation compared to the control group. The Oral Health Impact Profile (OHIP) demonstrated that aspects of physical pain and psychological discomfort presented the highest within the control group. Patients' responses showed that listening to natural auditory stimuli appeared to provide calm, relaxation and a better quality of treatment. Conclusions: The use of natural environmental sound stimuli is a novel successful tool that can be implemented to manage the gag reflex. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Traditionally for decades most oral maxillofacial prosthesis were fabricated using heat cured acrylic resin with or without Co-Cr metal base, however, recently polyamide materials that are processed thermally not chemically have been widely promoted for use as the perfect alternative to conventional hard acrylic dentures. The aim of this study was to assess the reaction of human mesenchymal stem cells (hMSCs) toward the biocompatibility of two different polymerized denture base resins. Materials and Methods: A total of 20 disc-shaped specimens (25 mm diameter and 3 mm thickness) were prepared according to the manufacturer's instruction as follows: Group (I) 10 discshaped heat cure acrylic resin samples polymerized conventionally in compression flasks, and Group (II) 10 disc-shaped thermoplastic acrylic resin samples polymerized using the injection molding technique. The cells used for this study were human bone marrow mesenchymal stem cells. Cytocompatibility was evaluated by WST-1 assay and live/dead fluorescent staining. The cells were observed under fluorescent microscope and photographed at 10x magnifications. Results: An increase of the survival cell rate was observed in samples of both groups with no statistically significant difference. Although the live/dead viability/cytotoxicity assay showed a green fluorescence cell in Group I and II with fewer scattered red fluorescence cell in Group II, the difference was not significant in both groups indicating that the materials of both groups were compatible with hMSCs. Conclusions: The current in vitro study concluded that the polymerization methods used in each group had no detrimental or negative effect on the biocompatibility of denture base resins. Our finding highlighted on the use of fluorescent live/dead viable/ cytotoxicity assay to study the biocompatibility and the viability behavior of the two-denture base resins. These findings are also support by WST-1 assay. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to determine the effect of ageing on the light intensity of quartz-tungsten-halogen (QTH) polymerization units in dental schools and dental clinics. Materials & Methods: Two dental schools and multiple public health dental clinics were visited and the light intensity of curing units was assessed. The age, make, model and service history were recorded. A calibrated radiometer (range 0-1000 nm) was used to measure the light intensity of 171 QTH units. At the end of each visit, the team members provided each dental clinic with a verbal report of the test results and recommendations on maintenance of light polymerization units. Results: The 171 units tested were from seven different manufacturers. The mean light intensity was 373.1 mW/cm2, the lowest intensity being 95.3 and the highest 526.60 mW/cm2. Only 29 QTH units recorded more than 500 mW/cm2; 102 units showed readings that ranged between 300 and 500 mW/cm2 and 39 units recorded readings below 300 mW/cm2. It was notable that one unit had light intensity reading of less than 100 mW/cm2. The age distribution was as follows: 35 units were more than 10 years old, 79 were from 5 to 10 years old and 57 were less than 5 years old. There was a high statistical significant relation between the mean light intensity and age (P = 0.001). Conclusion: Light intensity values used in some dental clinics were to be found lower than what is recommended for optimum polymerization of resin-based composite restorations. Awareness among dentists of the value of QTH light curing units and their commitment to care and maintenance are crucial to achieving optimum restoration properties. [ABSTRACT FROM AUTHOR]

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.

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 ( r 2 = 0.96, P < 0.001) and girls ( r < 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 ( 2 = 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., Competing Interests: There are no conflicts of interest.

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.