BackgroundThe application of computer-aided design computer-aided manufacturing (CAD CAM) technology in the fabrication of complete dentures, offers numerous advantages as it provides optimum fit and eliminates polymerization shrinkage of the acrylic base. Additionally, the porosity and surface roughness of CAD CAM resins is less compared to conventionally processed resins which leads to a decrease in the adhesion of bacteria on the denture base, which is associated with many conditions including halitosis and aspiration pneumonia in elderly denture wearers.AimTo evaluate the influence of tooth brushing with dentifrices on CAD CAM resin blocks in terms of abrasion resistance, surface roughness and scanning electron photomicrography.MethodsThis experimental study was carried out at the Faculty of Dentistry of King Abdulaziz University during 2016. A total of 40 rectangular shaped polymerized CAD CAM resin samples were subjected to 40.000 and 60.000 brushing strokes under a 200-gram vertical load simulating three years of tooth brushing strokes using commercially available denture cleaning dentifrice. Data were analyzed by SPSS version 20, using descriptive statistics and ANOVA.ResultsANOVA test revealed a statistical significant weight loss of CAD CAM acrylic resin denture base specimens following 40.000 and 60.000 brushing strokes as well as a statistical significant change (p=0.0.5) in the surface roughness following brushing. The CAD CAM resin samples SEM baseline imaging revealed a relatively smooth homogenous surface, but following 40,000 and 60,000 brushing strokes, imaging displayed the presence of small scratches on the surface.ConclusionCAD CAM resin displayed a homogenous surface initially with low surface roughness that was significantly affected following simulating three years of manual brushing, but despite the significant weight loss, the findings are within the clinically acceptable limits.

Prior research has shown that students' previous grade point average (GPA) is the best predictor for future academic success. However, it can only partly predict the variability in dental school performance. The aim of this study was to assess the predictive value of multiple mini-interviews (MMI) as an admission criterion by comparing them with the academic performance of dental students over a two-year period. All incoming undergraduate dental students at the King Abdulaziz University Faculty of Dentistry (KAUFD) during academic year 2013-14 were invited to participate in MMI. Students rotated through six objective structured clinical exam (OSCE)-like stations for 30 minutes total and were interviewed by two trained faculty interviewers at each station. The stations were focused on noncognitive skills thought to be essential to academic performance at KAUFD. The academic performance of these students was then followed for two years and linked to their MMI scores. A total of 146 students (71 males and 75 females) participated in an interview (response rate=92.9%). Most students scored in the acceptable range at each MMI station. Students' total MMI score, ambitions, and motives were significant predictors of GPA during the two years of follow-up (p<0.038 and p<0.

No abstract

Preliminary validity evidence supports the use of MMI scores as an admission tool for dental students, with respect to its response process, internal structure and relationship to other variables.

The use of ion-implantation to encourage osseointegration has been investigated using an in vitro model cell culture system and surface analysis. Polished titanium discs were implanted with calcium, potassium and argon ions. The adhesion of bone-derived cells was measured using radioactively labeled cells and the morphology examined using scanning electron microscopy. Similar numbers of cells were found to adhere to the potassium and argon-implanted titanium as to control (non-implanted) titanium. However, adhesion to the calcium-implanted titanium discs was significantly reduced. Moreover, although the cells were found to be well spread on the calcium and potassium-implanted titanium, a much greater proportion of cells appeared to remain rounded and poorly attached on the argon-implanted surface. These differences are discussed in relation to the observed surface roughness and chemistry, which were assessed using interferometry and X-ray photoelectron spectroscopy, respectively.

Thermoplastic resin displayed excellent thermal stability and the absence of residual monomer within the polymerized material, suggesting its suitability for the fabrication dentures.

During the past few decades, unalloyed titanium has been extensively used as a material of dental implant-supported restorations but it cause gingival discoloration and unnatural appearance of the surrounding soft tissue. Currently, yttrium oxide partially-stabilized zirconia (Y-TZP) is a ceramic of special interest because of its superior mechanical properties. This study was carried out with four one piece zirconium implants embedded on a standard acrylic resin mandibular edentulous model, the abutment of zirconium implant was classified into two designs and then laboratory test was applied with proposed biting force ( sensor (BS) and a bidirectional transmitreceive module. Our study concluded that the use of one piece Zirconium implant with box or parallel shape abutment head in implant supported over-denture without a need of cement, screws or plastics or metal housing for attachment in other types of implant had a superior results and easier maintenance and repair of the prosthesis if any complications occur.

No abstract