Students’ vulnerability in educational research

Dental teaching institutions in South Africa recently implemented “learner-centred” curricula and expected educators to alter their teaching styles accordingly, but perhaps without providing adequate training in this paedagogical philosophy. At the same time, the lecturers were required to conduct evidence-based research to evaluate the outcomes. Thus, clinicians/lecturers also became researchers, using their own students or student material for assessment purposes. Previously, this form of educational research, which was carried out in normal academic settings, was not subject to review by Institutional Review Boards (IRB). However, concerns have risen that learners may be a vulnerable population due to their position in the academic institution, and the power and knowledge differentials that exist between them and the lecturer/researcher. This raises ethical concerns regarding their autonomy and ability to provide free, voluntary, informed consent to be research participants. This paper questions whether educational research may lead to student vulnerability, and proposes some recommendations for educators and institutions involved in educational research.A study grant from the John E. Fogarty International Centre of the US National Institutes of Health as part of their programme entitled The International Research Ethics Network for Southern Africa (IRENSA), conducted at the University of Cape Town, South Africa.http://www.sada.co.z

Statistical terms Part 2 : Principles of research study design : understanding the options, indications and limitations

Consider this proposed study. AIM: This cohort case study will use a causal, cross sectional design, based on historical records, to explore and describe the long-term, sequential effects of eating. HO: This study will provide evidence to disprove the null hypothesis that "Of those who acquire the habit of eating, very few survive."http://www.sada.co.zaam2016Prosthodontic

Patients are people treating the person, not the problem

A health-care practitioner is an individual who provides preventive, curative, promotional or rehabilitative health care services in a systematic manner to people, families or communities. Sadly, many clinicians could rather be called disease treaters as they are more concerned with handling the symptoms of a disorder (which also pays the bills), than on promoting or supporting the health of the individual. This applies to an even greater extent in Dentistry where the field of focus is already small, and it is tempting to talk of patients in terms of “the tooth” or “the case”. This paper presents a more holistic approach towards patient management during different stages of life from birth to adulthood.www.sada.co.zahttps://www.sada.co.za/the-sadjam2019Prosthodontic

The effects of hydrochloric acid on all-ceramic restorative materials : an in-vitro study

OBJECTIVES: The aim of this in-vitro study was to assess the long-term effects of hydrochloric acid on the surface roughness of three all-ceramic restorative materials CEREC VITABLOC® Mark II CAD, IPS Empress CAD® and IPS e.max CAD®. MATERIALS AND METHODS: Six cylindrical specimens (10mm diameter, 3mm height) of each material type were prepared, using the CEREC CAD/CAM machine. The unpolished samples were immersed in 15ml hydrochloric acid (pH 2) at 370C. Before immersion (baseline) and at periods of 7.5 hours, 45 hours and 91 hours, the specimens were removed from the acid and two randomised areas (10μm X 10μm) were selected and tested on each. The atomic force microscope (Bruker Dimension icon) was used to assess surface roughness and surface area at baseline and after each exposure time. The materials were compared over time with respect to surface roughness and surface area (baseline, 1 month, 6 months, 1 year) in a repeated measures analysis of variance (ANOVA). RESULTS: Sample groups differed significantly for roughness (p<0.0001) and surface area (p<0.0001). For both parameters a significant interaction also existed between material and time (surface roughness: p=0.0085; surface area: p=0.0014). CEREC VITABLOC® Mark II CAD and IPS Empress CAD® had substantially higher levels of roughness and surface area than IPS e.max CAD®, which was also affected to a lesser extent over time. CONCLUSION: The results showed that IPS e.max CAD was least affected by long-term exposure to hydrochloric acid. CLINICAL SIGNIFICANCE: These results can aid the clinician in choosing the appropriate materials for patients who are bulimic or who suffer from gastro oesophageal reflux.http://www.sada.co.za2015-04-30am201

Evaluation of surface characteristics of titanium and cobalt chromium implant abutment materials

INTRODUCTION: Micro-organism adhesion and plaque formation is affected by surface free energy (SFE), surface roughness, hydrophilicity, surface chemistry, surface charge and the presence of proteins. AIMS: The aim of this study was to assess and compare surface characteristics of surgical grade cobalt chromium alloy (CCM) and of commercially pure titanium (cpTi). METHOD: Nine metallic cylinders were machined to precise standards from each material. Surface roughness was measured at four different points on each sample and the average Ra value was calculated for each material. Contact angles were obtained using the sessile-drop method and applied in calculating the SFE. Surface hardness was evaluated by means of a Vickers hardness micro-indentation. RESULTS: Surface roughness was similar for both metals,but total SFE values and Vickers surface hardness scores showed significant differences (p<0.0001). CONCLUSION: SFE analysis showed CCM to be more hydrophobic and that oral bacteria might therefore be less adherent than to cpTi. The mean Vickers Hardness scores of the cpTi were significantly lower (p<0.0001), suggesting that CCM may be more resistant to surface modifications and surface roughening, thus remaining smoother with less plaque accumulation than cpTi. This study demonstrated that CCM might be a suitable alternative implant abutment material.http://www.sada.co.zaam2013ay201

Treatment versus research : Part 5 : Bridging the boundaries

For clinicians wishing to embark on research, the obvious choice may be to use their large patient pool, already at their disposal. Gathering information from old files and records is relatively easy and harmless, as long as anonymity and confidentiality are maintained. However, if they choose to conduct investigations on new materials or techniques, their patients could inadvertently and unwittingly become study participants, which raises ethical concerns. This paper aims to clarify the difference between using novel approaches as part of routine clinical treatment and conducting clinical research, and explores the possibilities of straying over the fine dividing boundary, which could lead to “patient experimentation”.http://www.sada.co.zaam2017Prosthodontic

Comparison of alveolar osteitis with post implant removal osteitis (can a “dry socket” occur after implant removal?)

The introduction of dental implants spawned an exponential growth in the number of fixtures being placed to meet the increasing functional and aesthetic demands of patients. In response, manufacturers have flooded the market with new, cheaper systems, and many general practitioners have begun placing implants to support restorations. Enhanced life expectancy means that implants placed in younger people are expected to function effectively over many years. Studies have shown that a certain low percentage of implants will develop early or late complications,1 and that the risks are greater with increased usage.2 It is thus anticipated that practitioners will be faced with increasing numbers of implant-related complications that will require appropriate management, or even implant removal.1 Hence the majority of complications will be in older persons where healing may be compromised due to physiological ageing, systemic medication, or other age-related factors.https://www.sada.co.za/the-sadjam2018Prosthodontic

The accuracy of three impression transfer techniques for implant supported prostheses

Cast framework for osseointegrated implant retained prostheses need to be passively fitting so as not to place undue forces and stress concentrations around the fixtures. Impression materials and techniques play a key role in the accuracy and fit of the metal framework. In this study, three impression procedures were investigated to establish which was the most accurate, reliable and predictable. This included using smooth sided tapered transfer copings and unsplinted and splinted square undercut transfer copings. A metal plated master model was fabricated and used as the standard against which models poured using the different impression techniques were compared. Readings were taken with a Reflex Microscope and used to calculate the mean, standard deviation and deviation index for each test model. The results of this study suggest that direct coping transfer techniques provide comparable or better results than indirect coping transfers in master cast fabrication. There was no significant difference in impression transfer accuracy between splinted and non-splinted square impression coping transfer techniques

A comparison of preload values in gold and titanium dental implant retaining screws

This in vitro investigation compared the effect of using either gold or titanium retaining screws on preload in the dental implant- abutment complex. Inadequate preload can result in screw loosening, whilst fracture may occur if preload is excessive. These are the most commonly reported complications in implant-retained prostheses, and result in unscheduled, costly and time-consuming visits for the patient and the clinician. This study investigated changes in preload generation after repeated torque applications to gold and titanium screws. The test set-up consisted of an implant body, a cylindrical transmucosal abutment, and the test samples of gold and of titanium retaining screws. The implant bodies were anchored using a load cell, and the transmucosal abutments were attached using either gold or titanium retaining screws. A torque gauge was used to apply torque of 20Ncm, 32Ncm, and 40Ncm to the retaining screws. The preloads generated in each screw type were compared at each torque setting, and after repeated tightening episodes. In addition, the effect of applying torque beyond the manufacturers’ recommendations was also examined. Gold retaining screws were found to achieve consistently higher preload values than titanium retaining screws. Preload values were not significantly different from the first to the tenth torque cycle. Titanium screws showed more consistent preload values, albeit lower than those of the gold screws. However due to possible galling of the internal thread of the implant body by titanium screws, gold screws remain the retaining screw of choice. Based on the findings of this study, gold retaining screws generate better preload than titanium. Torque beyond the manufacturers’ recommendations resulted in a more stable implant complex. However, further investigations, with torque applications repeated until screw breakage, are needed to advise on ideal maintenance protocols.http://www.sada.co.za2015-08-30am201

Biaxial flexural strength of three ceramic oxide core materials

INTRODUCTION : Brittleness and low strength render conventional ceramic systems unsuitable for routine restorative use in molars. Modern, high-strength ceramic core materials such as high purity aluminum oxide (Al2O3) and yttrium - partially stabilized zirconia (Y-PSZ) have been designed for aesthetic, metal-free, all-ceramics in posterior teeth. AIMS AND OBJECTIVES : To compare the biaxial flexural strengths 1. of these two core materials. 2. To compare the strengths of Y-PSZ samples produced by two manufacturers. MATERIALS AND METHODS : Three groups of discs measuring 16mm diameter and 2mm thickness were prepared for each of the sample materials, high purity Al2O3, commercially available as Turkom-Cera, and Y-PSZ, commercially available as Cercon and LAVA. The Biaxial flexural strengths were measured using a Zwick Z010 Material Testing Machine. Reliability was compared using Weibull Moduli. RESULTS : Mean strengths for LAVA, Cercon and Turkom-Cera were 866.44, 586.92, 155.71 MPa respectively. Statistically significant differences were shown between the mean values. DISCUSSION AND CONCLUSION : This project showed that the samples of Y-PSZ had higher biaxial flexural strengths than those of high purity Al2O3. The biaxial flexural strengths of Y-PSZ, sourced from two manufacturers, are significantly different. It is suggested that Y-PSZ is suitable and indicated for restorative use in molar regions.https://www.sada.co.za/the-sadjam2018Prosthodontic