Magister Scientiae Dentium - MSc(Dent) (Restorative Dentistry)

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The restoration of the endodontically treated tooth: A review of the Literature. Supplemented by drawings and photographs of clinical cases taken by the author during operative procedures
(University of Stellenbosch, 1978) Orkin, Darel Alan; Orkin, Darel Alan
Many books, articles and reviews of this aspect of restorative dentistry have been published. An attempt has been made to correlate all the relevant material in order that a comprehensive review of most of the published literature could be presented under one cover. It is possible that certain aspects have been omitted, this would not have been deliberate but in a review of this nature every published article may not have been attainable.
A laboratory evaluation of conventional chemically activated and microfilled light activated composite restorative resins
(University of the Western Cape, 1986) Joseph, Vincent Phillip; Retief, Hugo
The purpose of this study was to evaluate in vitro, the tensile bond strengths of some conventional and light cured resins, to study the effects of etchants on polished and ground enamel using the scanning electron microscope, and to the resin/etched enamel examlne electron interface by scanning microscopy This study was divided into: 1) laboratory tensile bond strength study of 'four composite resin materials. 2) a scanning electron microscopic study of the effect of four etchants on enamel. 3) the S.E.M. examination of the interfacial zone after the application of a demineralizing agent. The tensile bond strength study consisted of testing the bond strengths of two macrofilled and two microfilled resins in common use. These resins were applied directly to the etched enamel surfaces of extracted human teeth by utilizing newly developed perpex stubs which allowed a uniform surface area and for light curing of the resin. In this laboratory study the extracted teeth and the composite filled stubs were stressed to failure of the material bond to tooth in an Instron Machine. Bond strengths were recorded and tabulated in Newtons/mm2. The application of statistical analysis by Analysis of Variance and Duncans Multiple Range Test showed that there was a significant difference in the bond strengths of some of the four materials. The scanning electron microscope study consisted of an examination of etched enamel, either polished or ground using the etchants supplied by the two manufacturers i.e. 3 M Dental Company and J&J Dental Company. The interfacial zones of the resin/tooth interface systems were examined, using the two macrofilled and the two microfilled resijs in the stUdY.! Differences were found to exis.t at this zone.
The taper of clinical crown preparations done by dental students and dentists in two African countries: a comparative analysis
(University of the Western Cape, 2004) Enechi, Theophilus Chukwuemeka; Osman, Yusuf I.; Dept. of Restorative Dentistry; Faculty of Dentistry
Crowns have been used since the 5th century AD to improve both the form and function of teeth in the mouth. A great proportion of the total expenditure on dental care is spent on the provision and replacement of crowns and bridges and the number is increasing every year. A full coverage crown is a restoration placed over a single prepared tooth or it acts as an abutment in a bridge for the restoration of a missing tooth or teeth. Crowns are considered successful only when they meet both the aesthetic and functional requirements of the patient. For these to be met, certain principles for the preparation of the abutment tooth must be adhered to; such principles include features that are incorporated in the tooth preparation that enable it to withstand the forces of dislodgement that the tooth is exposed to both at rest and function. These features are described as the retention and resistance form of the preparation and the important aspect of these is taper. The taper of a tooth preparation is inversely proportional to the retention provided by the preparation. Volumes have been written on the difficulties encountered in making crowns with an adequate taper. Training, experience and operating conditions are among the many determinants of taper obtained by clinicians. Taper values of 2º to 5º were recommended initially for successful crown restorations but over time it was realized that these values were difficult to achieve under clinical conditions without creating undercuts in the preparation. Besides it was shown that even higher taper values might provide adequate retention for crowns. In addition, extra-retentive features such as axial grooves and boxes have been shown to improve retention of crowns. Many of the new luting cements also have adhesive properties that contribute to better retention of crowns and bridges. Various studies have established the prevalent taper obtained by dental students, general practice dentists, residents and prosthodontists while some of these studies have compared the prevalent taper among the different categories of clinicians. None of the studies so far reported has shown the prevalent taper in this environment; all without exception have investigated conditions in Europe, North America and Asia. Aim: This study therefore investigated the prevalent taper obtained routinely under clinical conditions by dental students, general dental practitioners and prosthodontists in two African countries and compared them with the recommended range of 10º to 22º.Method: 432 dies of teeth prepared by students, general practice dentists, resident and practicing prosthodontists were collected and analysed for taper using the double silicone technique. This involved making silicone replicas of the dies, sectioning these at various points and using photographs of the sections to measure their taper. Comparisons of the tapers obtained were carried out between the students, general practitioners and prosthodontists as well as between taper obtained on the different tooth types. Results: Taper ranging from 2º to 100º was obtained on the various tooth types. A mean mesio-distal (MD) and bucco-lingual (BL) taper of 22.5º (SD 11.2) and 26.2º (SD 11.1) respectively and a mean overall taper of 24.3º (SD 9.2) were obtained. Prosthodontists obtained the lowest taper (MD = 20.5º (SD 10.6)), BL = 24. 5º (SD 10.1) and a mean overall taper of 22.5º (SD 8.4). Students were second with a mean MD taper of 23.8º (SD 10.1), BL taper of 26.1º (SD 10.9) and a mean overall taper of 25.0º (SD 8.4). The general practice dentists obtained a mean MD and BL taper of 24.5º (SD 12.4) and 29.1º (SD 12.1) respectively and a mean overall taper of 26.8º (SD 10.6). The lowest taper was seen on premolars while the highest was on molars. Conclusion and recommendation: Most of the preparations analysed had a taper outside the recommended range of 10º to 22º. However, these tapers were similar to those found in other studies. Routinely incorporating extra-retentive features into crown preparation designs will improve success of crown restorations and adhesive cements should be used whenever conditions that allow for adequate retention are not met. The importance of taper should be emphasized more in dental schools and tooth preparation support systems should be used for teaching wherever possible. The need for regular refresher courses for practicing dentists and prosthodontists cannot be over-emphasized.
The effect of dentine-bonding agents on the microleakage of provisional crowns
(University of the Western Cape, 2005) Moosa, Rustim; Geerts, Gavm; Dept. of Prosthodontics; Faculty of Dentistry
The use of provisional acrylic crowns is common practice with prosthodontic treatment. Provisional crowns are prone to marginal leakage and poor retention due to weak interim cements. The aim of this study was to assess the effect of the application of two different dentine-bonding agents on the microleakage of provisional crowns.
The retentive strength of bonded amalgam restorations
(University of the Western Cape, 2005) Banna, Trinadha Rao; Osman, Yusuf I.; Dept. of Restorative Dentistry; Faculty of Dentistry
Amalgam bonding agents have been shown to enhance retention of amalgam restorations by mechanical means. However, recent studies showed that the use o glass ionomer cements and resin cements as lining and bonding materials to amalgam restorations will increase the retentive strength of the amalgam restorations, hence reducing the micro leakage and secondary caries. The purpose of this study was to compare the relative retentive strength of conventional amalgam restorations and bonded amalgam restorations using resin adhesive, glass ionomer cements and resin cements.
An in vitro study of microleakage and surface microhardness of nanocomposite restorative materials
(University of the Western Cape, 2005) Majeed, Abdul; Osman, Yusuf I.; Dept. of Restorative Dentistry; Faculty of Dentistry
The demand for posterior aesthetic restorations has dramatically increased in recent years. Several new materials have been developed with improved aesthetic, adhesive and mechanical properties. However, microleakage elimination, especially if the margins are on dentine or cementum, and attainment of optimum mechanical properties for posterior use, are still questionable. The aim of this study was to investigate microleakage and surface microhardness of a nanofilled, a nanohybrid and an ormocer based nano-ceramic composite restorative material.
Prevalence of signs and symptoms of temporomandibular joint dysfunction in subjects with different occlusions using the Helkimo index
(University of the Western Cape, 2005) Kalanzi, Dunstan; Osman, Yusuf I.; Shaikh, A; Dept. of Restorative Dentistry; Faculty of Dentistry
The controversy surrounding the role of malocclusion and orthodontic treatment in temporomandibular joint (TMJ) dysfunction led to this study. The purpose of this study was to establish the prevalence and compare the status of signs and symptoms of TMJ dysfunction in four groups of adolescents and young adults. The groups consisted of 14 persons with normal occlusions, 23 with untreated malocclusions, 20 with malocclusions currently undergoing treatment, and 18 with treated malocclusions. The Helkimo index was used to collect the TMJ dysfunction data. The results showed that the untreated malocclusion group had the most number of persons with signs and symptoms of dysfunction, but the differences between the groups in the distribution of persons according to the anamnestic and clinical dysfunction indices were not statistically significant. There were also no statistically significant differences in the distribution of signs and symptoms between boys and girls. According to anamnesis, the most frequently reported symptoms were joint sounds and headaches or neckaches occurring more than twice a week. Amongst the clinical signs and symptoms, the most commonly occurring were joint sounds on auscultation and muscle tenderness on palpation. In light of the small study sample and the absence of any substantial differences between the four groups, the role of malocclusion and orthodontic treatment in the aetiology of TMJ dysfunction remains obscure.
Do complete dentures improve the quality of life of patients?
(University of the Western Cape, 2006) Adam, Razia Zulfikar; Geerts, G Prof; Lalloo, R Prof; Dept. of Restorative Dentistry; Faculty of Dentistry
Few studies have documented the impact of complete dentures on patients’ oral health-related quality of life. Objectives: The purpose of this study was to investigate the relationship between gender, age, socioeconomic status and denture satisfaction
An in-vitro study assessing the color stability of different provisional crown and bridge restorative materials
(2006) Barbara, Ndagire; Osman, Yusuf I.; Grobler, S.
The aim of this study was to investigate the color stability of two provisional restorative materials used in crown and bridge cases upon exposure to different tea staining solutions and to evaluate the effectiveness of a polishing technique in removing the tea stains from the stained provisional restorative materials.
Photoelastic stress patterns produced by the angled distal implants in the All-on-Four concept
(University of the Western Cape, 2006) Begg, Tasneem; Geerts, Gavm; Gryzagoridis, J.; Dept. of Restorative Dentistry; Faculty of Dentistry
The purpose of this study was to investigate the stress produced around the angled distal implants under simulated occlusal loading in the All-on-Fourª concept by means of two-dimensional photoelastic stress models.
Surface hardness of different shades and types of resin composite cured with a high power led light curing unit
(University of the Western Cape, 2006) Lodhi, Tariq Abbas; Strydom, C.; Osman, Yusuf I.; Dept. of Restorative Dentistry; Faculty of Dentistry
Light-emitting diode (LED) curing lights were introduced to the dental market promising a higher curing efficiency than halogen-based lights. The earlier generation curing lights, however, proved not to be as effective as halogen lights. As a result 3M ESPE introduced a new high-powered LED curing light, the Elipar FreeLight 2, that delivers a greater irradiance. and threfore greater energy density than its precursor. Due to these changes, the light's manufacturer claims that the FreeLight 2 can cure resin composites at half of their recommended curing time. The aim of this study was to compare the effectiveness of cure when a FreeLight 2 was used to sure composite samples at 100% and at 50% of the recommended curing time.
Comparison of time taken and breakage of six different endodontic systems to prepare molar teeth
(University of the Western Cape, 2006) Brittain, Roger; Saayman, C.M.; Dept. of Restorative Dentistry; Faculty of Dentistry
The purpose of this study was to determine duration time, breakage and apical displacement, whilst using six different endodontic filing systems to prepare molar teeth. A total of 96 molar teeth were used in the study, divided equally, ie 16 teeth per system selected randomly, totalling 48 canals per system. A standardised access cavity was prepared for all the teeth before selection. The canals were filed according to the manufacturers’ guidelines. The result showed that PROTAPER®, K3™ and the combination of: HERO Shaper®, HERO Apical® and Endoflare® (Referred from hereon as HERO System for convenience) were statistically faster than PROFILE® and FlexMaster®, which were in turn faster than AETTM. Although breakage did occur in K3™ and HERO System this was not deemed statistically significant. Apical displacement occurred in the form of Type 1 in the AETTM, PROFILE® and HERO System, but once again this was not statistically significant. It was concluded that more aggressive cutting features such as a positive rake angle, pyramidal shaped tip, progressive taper and absence of radial lands, if present, could have enabled K3™, HERO System and PROTAPER® to have faster times, and in addition these features did not compromise these systems with regard to apical foramina transportation and breakage.
Dentine permeability and cytotoxicity of a dentine bonding agent
(University of the Western Cape, 2006) Du Bois, Alexander Hermann; Grobler, S.R.3; Dept. of Restorative Dentistry; Faculty of Dentistry
The objectives of this study were to create an in vitro situation which closest resembled the clinical situation by inclusion of human dentine discs at a specified anatomic location as barrier and evaluating if comparable or graded perfusion could be identified as well as whether a link existed between dentine thickness and permeability. The other leg of the study was to evaluate the cytotoxicity of Xeno III, one of the newly released new generation dentine bonding agents and to evaluate its cytotoxicity in an in vitro pulp chamber device, determining which thickness of dentine would be able to protect the dental pulp from noxious substances in the bonding agent.
A comparative study to evaluate patient satisfaction with conventional dentures and implant retained overdentures
(University of the Western Cape, 2006) Al-Makki, Amjad; Osman, Yusuf I.; Wilson, V.J; Dept. of Restorative Dentistry; Faculty of Dentistry
The edentulous jaw is a common feature in elderly patients that had lost their teeth during life due to local reasons such as poor oral hygiene and dental caries as well as periodontal disease. Hence these patients are the victims of biological phenomenona that lead to difficulties in different aspects of patient comfort with dentures. Clinicians are always concerned to minimize these difficulties and increase patient comfort through manufacturing a proper prosthesis to substitute for the loss of the natural teeth as well as the surrounding structures for optimum satisfaction and improved quality of life of the patient. The aim of this study was to evaluate patient satisfaction regarding function and aesthetics with conventional mandibular dentures and implant retained mandibular overdentures in denture wearers.
Mechanical and handling properties of light-cured acrylic resin custom tray material
(University of the Western Cape, 2007) Khan, Saadika B.; Geerts, Gavm; Dept. of Restorative Dentistry; Faculty of Dentistry
Both light-cured (LC) and chemically-cured (CC) acrylic resin custom tray materials are used at the Oral Health Centre, Faculty of Dentistry, University of the Western Cape. At present, the CC acrylic is the standard for formal undergraduate teaching and training. The LC material is not part of routine didactic teaching as little evidence-based scientific information is available with regards to its properties and its usage in the clinical environment. Negative effects have caused researchers to focus on alternatives and to research for other materials with more advantageous properties. The objectives of this study was to determine the linear dimensional shrinkage and fracture toughness of light-cured acrylic custom tray materials and compare it to the chemically-cured type. Also to evaluate the acceptance of light-cured acrylic resin custom trays by undergraduate students.
Analysis of coronal discoloration from commonly used obturation materials
(University of the Western Cape, 2007) Elkhazin, Mohamed M. A.; Osaman, Y.I; Dept. of Restorative Dentistry; Faculty of Dentistry
The objective of this study was to assess coronal discoloration due to four commonly used endodontic sealers with gutta-percha, using spectrophotometric analysis. Extracted human teeth were obturated with the experimental sealers and GP. The sealers that were tested included AH Plus, EndoRez, and Kerr Pulp Canal Sealer. The teeth were maintained in a moist environment at 37 C. Immediate pretreatment readings of the crowns of the extracted teeth with a spectrometer were used as baseline data. Subsequent readings were taken every two weeks for two months. Results were analysed using Wilcoxson Signed Rank sum test and Kruskal Wallis test.
The safety and efficacy of the propofol/ Alfentanil/ Ketamine-bolus technique in midazolam pre-medicated patients undergoing office based plastic or reconstructive surgery
(University of the Western Cape, 2007) Venter, J. C.; Roelofse, James; Faculty of Dentistry
The purpose of this research project was to assess the safety and efficacy of a combination of drugs for conscious sedation in patients undergoing office-based plastic and reconstructive surgery. A pilot study was done to determine the safety of the co-administration of the drugs used in the sedation technique.
The sealing ability of mineral trioxide aggregate (MTA) used as retrograde filling agent in roots with filling and unfilled root canals: an in vitro comparative study
(University of the Western Cape, 2007) Marian, Eduard Alexandru; Saayman, C.M.; Dept. of Endodontics; Faculty of Dentistry
The aim of this study was to determine whether the presence or absences of the root canal seal had any influence on the retrograde sealing ability of MTA (mineral trioxide aggregate).
Influence of a bleaching agent on stained direct composite resins
(University of the Western Cape, 2008) Wanjau, Caroline; Osman, Yusuf I.; Dept. of Restorative Dentistry; Faculty of Dentistry
Despite the phenomenal strides in research of dental resin composites regarding their physical and mechanical properties, discolouration, either intrinsic or extrinsic still remains a major drawback and is one of the main reasons for the replacement of these restorations. Toothbrushing and polishing procedures have been attempted to eliminate extrinsic staining without optimal results. Vital tooth bleaching has over 90% success rates in whitening discoloured teeth and this may be an alternative treatment modality for discoloured composite resins. Aim: The aim of this study was to determine whether tooth bleaching agents alter the colour of stained direct composite resins. Material and Method: 60 disc shaped specimens (9 x 2mm) of Filtek Supreme XT were prepared. They were randomly divided into 3 groups (n = 20) and exposed to either one of two experimental staining agents, tea or red wine, or artificial saliva (control) continuously over a 7-day period. They were all then bleached with Opalescence Xtra Boost, a chemically activated in-office whitening agent for 3, weekly sessions of a half hour each, broken into 2, fifteen minute cycles. Colour determinations were made using a reflectance spectrophotometer, from baseline, after each day of staining, after the bleaching treatments and after a 1 week rehydration period. The CIE Lab colour space was used and colour changes were monitored using ΔE, that was calculated during intervals between the experimental episodes using L, a and b values. A ΔE ≥ 3.3 represented colour changes that were deemed clinically noticeable. Data analysis was carried out using Microsoft excel and a non-parametric test (Wilcoxon Signed Sum Rank Test) with a significance level set at ≤ 0.05 for colour differences that are statistically significant. Results: Both staining solutions discoloured the composite resin samples, but red wine produced greater colour changes than tea. After bleaching, the specimens in the tea group reverted to baseline colour with a ΔE ≤ 3.3 but those in the red wine group did not revert to baseline values with a ΔE ≥ 3.3. Conclusion: Filtek Supreme XT, a nanocomposite, is susceptible to discolouration by chromogenic beverages. Red wine produced deeper staining than tea. Opalescence Xtra Boost was effective in removing tea stains but not red wine stains.
Oral health of institutionalised children in a place of safety in Moshi, Tanzania
(University of the Western Cape, 2008) Rao, Sravanam Venkateswara.; Louw, A.J.; Faculty of Dentistry
The aim of the study was to analyze oral health status(dental caries, periodontal conditions, fluorosis and malocclusion) of institutionalised children at Amani and Mkombozi street children homes in Moshi town, Tanzania. 100 street children participated. A cross sectional survey of street children between 12-18 years was carried out based on WHO guidelines. Self administered questionnaires were used to collect information from the caregivers.The findings indicate clear need to improve oral hygiene among these children.

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