Research Articles

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A comparison of the bond strengths of microwave- and water bath-cured denture material.
(Elsevier, 1993-11) Geerts, G; Jooste, CH
A comparison was made of the shear bond strengths between microwave-polymerized and conventional water bath-cured polymethyl methacrylate (PMMA) bonded to denture teeth. Four groups of 15 specimens were prepared and shear bond strengths obtained by use of standardized laboratory testing methods. The results showed that microwave-cured PMMA demonstrated significantly (p 0.0001) higher bond strengths than conventional PMMA, and priming of the denture tooth surface with monomer liquid yielded significantly higher bond strengths than other surface treatment (p 0.0001).
Comparison of the clinical abrasion resistance of six commercially available denture teeth.
(Elsevier, 1997-01) Jooste, C; Geerts, G; Adams, L
Purpose: Clinical abrasion of denture teeth has certain implications when dentures are worn in excess of the average useful lifetime. The purpose of this study was to evaluate clinical denture tooth wear over a period of 3 years. Material and methods: The wear of six commercially available denture teeth (Premierdent, Acrotone, vitapan, Rx1, Duravite, and Ivoclar Orthosit) and a seventh combination of teeth was compared. Seventy patients with complete dentures were divided into seven groups of 10 each to form the study population. Results: There were no significant differences among the commercial denture teeth. Porcelain/Vitapan teeth exhibited the highest amount of abrasion. Significant wear was also measured between the Ivoclar Orthosit and Porcelain/Vitapan teeth.
Gelingualiseerde okklusie in die Suid-Afrikaanse konteks.
(2002) Oberholzer, TG; Geerts, G
The search for the ideal artificial tooth arrangement that maximizes denture stability, comfort, aesthetics, and function has occupied the dental literature for many years and still continues to do so. Of the many occlusal schemes that have been presented to the dental profession, that of lingualized occlusion has emerged as one of the more popular. The popularity of lingualized occlusion stems from the simplicity and flexibility of the concept and from its wide application to clinical practice (Parr & Ivanhoe, 1996). The registration of a repeatable correct centric jaw relation is not always possible. We don't know whether the patient will use centric relation during normal function. It is therefore useful to provide the patient with some freedom of movement around centric. lingualized occlusion provides freedom in centric. For many dentists the arrangement of artificial denture teeth into balanced occlusion is difficult and time consuming. As a result this task is most often performed by the dental technician. In the South African countryside dental laboratories are often far away. If dentists perform the arrangement of the denture teeth, time and costs can be saved. The mounting of denture teeth in lingualized occlusion is simple and fast. This will motivate dentists to arrange denture teeth themselves, with obvious benefits for both the patient and the dentist. The School of Oral Health Sciences of the University of Stellenbosch teaches this concept to its undergraduate students in order to improve the prosthetic service to the large edentulous population of South Africa.
An implant-supported auricular prosthesis: a team effort between two South African tertiary institutions
(South African Dental Association, 2002) Geerts, Greta; Lombard, G.
Primary osseo-integration with cranio facial implants is so reliable that it may be considered routine. Arcu ri ef nl.' reported that the use of titan ium endosseous screw implants proved to be a successful, predictable, and quali ty-of-life-enhancing technique for prosthetic anchorage in the midface region. Nishimura el nl.' reported a 100% success rate for implants used for auric ular prosth eses.This may be part ly the resu lt of a generous thlckness of compact bone in the craruu m . The Division of Prosthodontks, School for Oral Health Sciences, Universi ty of Stellenbosch and the Department of Dental Services, Faculty of Scien ce, Peninsula Technicon collabora ted to provide a maxillofacial serv ice and to create a training opportunity for senior undergraduate s at the two tertiary institutions. This article describes the prosthodontic management of an implant-supported auricu lar prosthe sis.
A comparison of the accuracy of two methods used by pre-doctoral students to measure vertical dimension
(Elsevier, 2004-01) Geerts, G; Stuhlinger, ME; Nel, DG
Statement of problem. Measuring vertical dimension is a soft-tissue measurement. Therefore, inaccuracy may occur. Purpose. The purpose of this study is to compare the accuracy of the Willis gauge method with the caliper method. Material and methods. The Willis gauge measures the distance between the septum of the nose and the chin. The caliper method measures the distance between reference points on the tip of the nose and the chin. Twenty predoctoral students applied both methods 10 times in measuring the rest vertical dimension (RVD) and the occlusal vertical dimension (OVD) of a single edentulous patient. The measurements obtained from one experienced clinician were selected as controls for the interocclusal distances (IOD) for the Willis and the caliper methods, respectively. One-sided t tests and a 1-sided nonparametric test were used to determine significant differences between the 2 methods ( .05). Results. The variances in the RVD values for the Willis gauge method were higher than for the caliper method for most students. A Wilcoxon signed rank test showed that the accuracy of the OVD measurements for the caliper method was significantly better than for the Willis gauge method (P .001). This was not the case for the RVD measurements (P .073).The average IOD for the Willis method was significantly higher than the control IOD (P .026). The average IOD for the caliper method was not significantly larger than the control (P .1303). Conclusion. This study showed that the use of the caliper method by predoctoral students was a significantly more reliable method of measuring the OVD for the patient evaluated
Gender and race distribution of dental graduates (1985 - 2004) and first year dental students (2000 - 2005) in South Africa
(South African Dental Association, 2005) McMillan, Wendy; Lalloo, R.; Gugushe, T.S.; Ligthelm, A.J.; Evans, W.G.; Moola, Mohamad H.
This paper, written at the close of a decade of democracy in South Africa, sets out to analyse the demographic profile of dental graduates from 1985-2004 at the five Faculties/Schools of Dentistry in South Africa. A comparison of the profiles for the pre-democracy (1985-1994) and post-apartheid (1995-2004) periods has been made. The demographic profile of first year dental students from 2000-2005 is also presented. From 1985-1994, most dental graduates were male (79%), but this changed substantially from 1995-2004, with females comprising 46% of those graduating. In the pre-democracy period, more than three-quarters of all graduates were White (78%), decreasing to 46% in the post-apartheid period under review. Black graduates increased from 6% to 24% across the two study periods. Amongst the first year dental student intake from 2000- 2005, females comprised 57%. There was an almost equal distribution across the White, Black and Asian groups. Dental faculties/schools have made important strides in transforming the demographic profile of their students. The percentage of Black graduates, however, needs to be significantly increased if it is to reflect the national population. Faculties/schools must further ensure that able students from working class background are identified and considered for acceptance into the undergraduate dental programme, and should then be offered the necessary academic and mentoring support to enable success.
Aesthetic reconstruction with fiber-reinforced polymerceramic crowns: a case study
(South African Dental Association, 2005) Osman, Yusuf; Rahbeeni, Ricky
Adhesive dentistry is rapidly evolving. Two main incentives drive this evolution - advances made in adhesive techniques combined with a demand for aesthetic restorations by patients .Patients want their teeth restored not only anatomically, but also aesthetically. Adhesive materials and indirect restorations currently available allow for these needs to be met in most instances using the concept of "minimally invasive" and "minimal intervention" dentistry.
"We are not in the least bit used to these ways of studying": Developing academic competence in all students
(American Association of Dental Schools, 2005) McMillan, Wendy
This article is located in the field of academic development in oral health science education. Specifically, it examines the academic difficulties experienced by oral hygiene students in their transition from high school to university. A qualitative approach was employed to elicit student and lecturer perceptions. Drawing on empirical evidence from a case study of a cohort of first-year oral hygiene students at a dental faculty in South Africa, the article contributes to an understanding of how first-year university students might be better prepared for the challenges of reading and writing in higher education. The voices of lecturers and students are used to highlight the nature of the difficulties that students experience in the transition from high school to university. The suggestions that students made regarding how the transition might be eased are also examined. The final section draws on these suggestions and presents a working model for an academic development module for first-year oral health students.
Mapping an appropriate health promotion approach for crèches in an informal settlement
(John Wiley & Sons Ltd, 2005) Brijlal, Priscilla; Gordon, Natalie
People living in informal settlements in South Africa experience the double burden of poverty and ill health. Wallacedene, an informal settlement was highlighted in the media as being a socially and otherwise deprived community, with many accompanying health problems. Aim: It was against this background that this study was conducted to gain a better understanding of the health and oral health status of children attending crèches in Wallacedene.
Aesthetic clasp design for removable partial dentures: A literature review
(South African Dental Association (SADA), 2005) Khan, Saadika; Geerts, Greta
Removable partial dentures (RPD) are an effective and affordable treatment option for partial edentulism. If the main reason for seeking treatment is the need for improved aesthetics, treatment should be geared towards achieving this goal. This article is the result of a literature study on aesthetic clasp design for the conventional RPD. In this context, the position of the clasp on the tooth, clasp types, clasp material and alternative methods of retention are reviewed. Although published in reputable journals, the authors report that many articles published on this subject are of a descriptive nature and lack scientific evidence. Therefore, clinicians are encouraged to be critical in their interpretation of literature and the application of published information in their clinical practices.
"Quality is bound up with our values" - Evaluating the quality of mentoring programmes
(Routledge, 2005) McMillan, Wendy; Parker, M.E.
This paper discusses quality evaluation of health sciences mentoring programmes. The discussion highlights the way in which perceptions of what constitutes quality shape evaluative purposes. Potential tensions between the evaluative purposes of various stakeholders are brought to the fore. To this end, the discussion explores the ways in which accountability shapes the evaluative purposes of funders and how the desire for programme knowledge and development frames the evaluative purposes of academics. Various approaches to programme evaluation are examined. The potential of reflective practice as a tool for examining quality for knowledge and development of programmes is considered. The paper concludes by presenting a framework for evaluating various aspects of quality in mentoring programmes.
The impact of new complete dentures on oral health-related quality of life
(South African Dental Association, 2007) Adam, R.Z.; Geerts, Greta; Lalloo, R.
OBJECTIVE: To investigate the relationship between complete dentures and oral health-related quality of life (OHRQol). METHOD: Seventy-six patients were conveniently selected from the waiting list for complete dentures. At the first visit (pre-treatment) the patients were interviewed using the Ora Health Impact Profile for Edentulous Patients (OHIP-EDENT). Sixty-three of these patients were interviewed telephonically 2 to 3 months after receiving their new complete dentures (post-treatment). RESULTS: Mean domain scores were significantly lower post treatment for psychological discomfort and disability, social disability and handicap. CONCLUSION:This study shows that after the provision of a new set of complete dentures the OHRQoL of patients improved significantly on four of the seven domains for the first 2 to 3 months post-insertion.
Understanding diversity as a framework for improving student throughput
(Maastricht University, 2007) McMillan, Wendy
INTRODUCTION: Literature suggests that a diverse body of healthcare graduates could extend health service delivery. However, the literature also indicates that the throughput of minority, working class, and historically disadvantaged students is problematic. Poor throughput is attributed to the way that university environments alienate some students. This brief communication highlights lessons learned from exploratory interviews with four first-year oral hygiene students at a university in South Africa. It provides insight into the issues that contribute to academic success and failure. METHODS: Semi-structured, individual interviews, to gain information regarding students’ university academic experiences were conducted. Enablers and barriers to learning identified in the literature were used to capture themes. FINDINGS: The following three themes emerged: educational identity, language and finances. The analysis showed how a white middle class student recognized practices that are rewarded at university and how three, working-class, black students experienced tension between their expectations and experiences and the university culture. However, far from being victims, these students provided suggestions on how their transition might be facilitated. CONCLUSION: Evidence suggests that these students wanted both to be apprenticed into the new way of doing things while having their differences acknowledged. A model for education that initiates learners and also challenges the culture of power is suggested.
Oral health care for children attending a malnutrition clinic in South Africa
(John Wiley & Sons, Inc, 2007) Gordon, Natalie
Most health problems dealt with at a primary care level have an oral health impact, making it vital for oral health services to find means to integrate with other facility-based programmes at primary health care (PHC) centres. Aim: 1) To determine the oral status of the children attending a facility-based nutrition programme and the oral health knowledge, attitude and practices of their parents ⁄ caregivers; and 2) To develop a framework for an oral health component to complement this programme.
The use of light-cured acrylic resin for custom trays by undergraduate dental students: A survey
(South African Dental Association (SADA), 2008) Khan, Saadika; Geerts, Greta
This study aims to evaluate the acceptance of light-cured acrylic resin for custom trays by dental students. A questionnaire addressing the use and handling properties of both light-cured (Megatray, Megadent, Germany) and chemically-cured (Excel, Wright Health Group, UK) custom tray materials was distributed amongst undergraduate dental students of the University of the Western Cape. Of a total of 196 dental students, 38 were absent on the day of the survey. Of the 158 questionnaires that were distributed and returned, 18 did not meet the inclusion criteria and 1 person chose not to participate. Of the 139 participating students, 98 were in 4th year, 41 in 5th year. With regards to the light-cured acrylic custom tray material, 77% used it most often, 64% said it saved time and 62 % said that it was easier to handle. Fifty two percent indicated that both types of materials should be taught in undergraduate training, 26% preferred the light-cured acrylic resin custom tray material, 20% suggested that only the light-cured resin be used and no one suggested the chemically-cured resin exclusively. The study concluded that most undergraduate students positively accepted the light-cured resin, but training in the use of both materials was recommended.
The use of light-cured acrylic resin for custom trays by undergraduate dental students: a survey
(South African Dental Association, 2008) Khan, Saadika; Geerts, Greta
INTRODUCTION: It is unknown how the use of a light-cured acrylic resin is appreciated over the traditional chemically cured one for the construction of special trays in a teaching environment. OBJECTIVE: To evaluate the acceptance of light-cured acrylic resin for special trays by dental students. METHOD: A questionnaire addressing the use and handling properties of both materials was distributed amongst undergraduate dental students of the University of the Western Cape. RESULTS: Of a total of 196 dental students, 38 were absent on the day of the survey. Of the 158 questionnaires that were distributed and returned, 18 did not meet the inclusion criteria and 1 person chose not to participate. Of the 139 participating students, 98 were in 4th year, 41 in 5th year. With regards to the light-cured resin, 77% used it most often, 64% said it saved time and 62 % said that it was easier to handle. Fifty two percent indicated that both types of materials should be taught in undergraduate training, 26% preferred light-cured, 20% suggested that only the light-cured resin be used and no one suggested the chemically-cured resin exclusively. CONCLUSIONS: Most undergraduate students positively accepted the light-cured resin, but training in the use of both materials was recommended.
Effect of four different Opalescence tooth-whitening products on enamel microhardness
(South African Dental Association, 2008) Majeed, Abdul; Grobler, Sias Renier; Moola, Mohamad H.; Rossouw, Roelof; van Wyk Kotze, Theuns
OBJECTIVES: The purpose was to evaluate the effect of various Opalescence tooth-whitening products on enamel. METHODS AND MATERIALS: Enamel blocks were exposed to Opalescence PF 10% Carbamide Peroxide (n = 10), Opalescence PF 20% Carbamide Peroxide (n = 10), Opalescence Trèswhite Supreme 10% Hydrogen Peroxide (n = 10) and Opalescence Quick PF 45% Carbamide Peroxide (n = 10) according to the manufacturer's instructions. The control group was enamel blocks (n = 10) kept in artificial saliva. The values were obtained before exposure and after the 14-days treatment period. Enamel blocks were kept in saliva between treatments. Indent marks on enamel blocks were examined using the scanning electron microscope for treatment effects. RESULTS: All four different Opalescence products damaged enamel. The most damage was done when treated for a long period (112 hours). SEM images also showed damage to enamel by all 4 products. Opalescence with 10% and with 20% Carbamide Peroxide showed the highest damage, which also differed significantly (p < 0.05) from the saliva control group (p < 0.05; Tukey-Kramer Multiple comparison test). CONCLUSION: All 4 Opalescence products damaged enamel. Higher damage was done by the 10% carbamide peroxide and 20% carbamide peroxide products because of the much longer exposure period (112 hours in comparison to 7 hours).
The effect of different reinforcements on the fracture toughness of materials for interim restorations
(Elsevier, 2008) Geerts, Greta; Overturf, Jan-Hendrik; Oberholzer, Theunis
STATEMENT OF PROBLEM. Fracture of an interim fixed partial denture (FPD) may jeopardize the success of the interim prosthodontic treatment phase and cause patient discomfort. PURPOSE. The purpose of this study was to compare the fracture toughness of a polymethyl methacrylate (PMMA) resin and a bis-acryl composite (BAC) resin reinforced with stainless steel wire, glass, and polyethylene fiber. MATERIAL AND METHODS. Four groups (n=13) of each of the 2 materials were prepared for the single-edge 3-point-bending test. Three groups had the different reinforcements, and the group without reinforcement served as control. Using a universal testing machine, peak load to fracture was recorded and fracture toughness (KIC) was calculated in MNm-1.5. Median KIC values were compared by means of nonparametric ANOVA (Kruskal-Wallis test, α=.05). RESULTs. For the controls, the fracture toughness for PMMA resin (KIC=27.9) was significantly lower (P<.01) than for BAC resin (KIC=31.2). Glass fibers and stainless steel wire reinforcements produced significantly higher fracture toughness for both PMMA (KIC=34.4, P<.01, and KIC=39.0, P<.001, respectively) and BAC resin (KIC=42.3, P<.001, and KIC=44.0, P<.001, respectively), but the polyethylene fibers did not (KIC=33.1, P>.10, for BAC resin and KIC=25.8, P>.10, for PMMA resin). There was no significant difference between the fracture toughness of the wire and glass fiber reinforcements for both interim materials (P>.10 in both instances). CONCLUSIONS. Of the 3 reinforcement methods evaluated, wire and glass fiber reinforced the PMMA and BAC resin materials best.
Antimicrobial activity of two South African honeys produced from indigenous Leucospermum cordifolium and Erica species on selected micro-organisms
(BioMed Central, 2008) Basson, Nicolaas; Grobler, Sias Renier
Background: Honey has been shown to have wound healing properties which can be ascribed to its antimicrobial activity. The antimicrobial activity can be effective against a broad spectrum of bacterial species especially those of medical importance. It has also been shown that there is considerable variation in the antimicrobial potency of different types of honey, which is impossible to predict. With this in mind we tested the antimicrobial activity of honeys produced from plants grown in South Africa for their antibacterial properties on selected standard strains of oral microorganisms. Methods: The honeys used were produced from the blossoms of Eucalyptus cladocalyx (Bluegum) trees, an indigenous South African plant Leucospermum cordifolium (Pincushion), a mixture of wild heather shrubs, mainly Erica species (Fynbos) and a Leptospermum scoparium (Manuka) honey. Only pure honey which had not been heated was used. The honeys were tested for their antimicrobial properties with a broth dilution method. Results: Although the honeys produced some inhibitory effect on the growth of the microorganisms, no exceptionally high activity occurred in the South African honeys. The carbohydrate concentration plays a key role in the antimicrobial activity of the honeys above 25%. However, these honeys do contain other antimicrobial properties that are effective against certain bacterial species at concentrations well below the hypertonic sugar concentration. The yeast C. albicans was more resistant to the honeys than the bacteria. The species S. anginosus and S. oralis were more sensitive to the honeys than the other test bacteria. Conclusion: The honeys produced from indigenous wild flowers from South Africa had no exceptionally high activity that could afford medical grade status.
Effect of an antifungal denture liner on the saliva yeast count in patients with denture stomatitis: a pilot study.
(Wiley, 2008-09) Geerts G, G; Stuhlinger, ME
Although in vitro studies on the release of antifungal agents from tissue conditioners have been done, no in vivo research on the topic could be found. The purpose of this study was to determine the in vivo effect of an antifungal agent released from a tissue conditioner on the salivary yeast count. Forty edentulous patients with denture stomatitis caused by Candida albicans were divided in two groups. Group 1 (control) was treated with a tissue conditioner only. Group 2 was treated with a tissue conditioner incorporating 500 000 U nystatin. Oral rinses were performed by both groups before treatment and every second day during treatment for a period of 14 days. Total yeast counts of the oral rinses were performed and the averages and standard deviations for both groups calculated and logarithm-transformed data of the counts over time were statistically analysed using the Wilcoxon signed-rank test. The average oral rinse yeast count of the control group decreased up to day 4. Thereafter, the count increased till the end of the test period. At day 14, the oral rinse yeast level was higher than the pre-treatment level. The average yeast count of the test group decreased up to day 7. Thereafter, the count increased but remained significantly lower (P = 0·01) than the control group and did not return to its pre-treatment level. A nystatin-containing short-term denture liner significantly decreases the salivary yeast count of patients with denture stomatitis compared with a liner without nystatin.

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