Department of Orthodontics

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The discipline of Orthodontics focuses on the growth and development of the craniofacial complex and dental occlusion, and the treatment of abnormalities related to these structures.

The Department of Paediatric Dentistry conducts an undergraduate and a postgraduate programme to enable students to manage the child dental patient. The postgraduate programmes consist of a postgraduate diploma in dentistry part-time and a masters programme full time.

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The prediction of the size of unerupted canines and premolars in a contemporary orthodontic population
(1974-04) Tanaka, Marvin; Johnston, Lesley
Linear regression equations for the prediction of the mesiodistal widths of unerupted canines and premolars were calculated for a large sample of recent orthodontic patients. The form of the equations, as well as the size of the various confidence belts, were generally similar to those in the widely used but incompletely characterized Michigan Mixed Dentition Analysis. Although either set of tables would seem equally appropriate, a simple approximation— half the width of the mandibular incisors plus either 11.0 for the maxillary canine-premolar segments, or 10.5 for the mandibular segments— is of comparable accuracy. The
The Physical and Mechanical Aspects of Orthodontic Appliances
(University of the Western Cape, 1978) Bibby, R.E; Bibby, R.E
These laws were first published in Latin,in 1687.The first law may be literally translated thus, Every body continues in its state of reat or of uniform motion in a straight line ,unless it is compelled to change that state by impressed force. This meano that if a body is at rest it will remain so unless some force acts on it,if in motion ,the velocity of motion must continue uniform unless some force acts to increase it or diminish it. Also the direction of motioA mast continue unchanged and therefom rectilinear unless some force causes it to be diverted. This law therefore supplies us with a definition of force; Force is that which produces or tends to produce, motion 0.' change of motion. Newton's second law of motion may be translated as follows:- Newton's second law of motion may be translated as follows:- The change of motion (produced)is proportional to the impressed force producing it,and pursues the direction in which that force is impressed. This law leads to a method of measuring forces. If we change the velocity with which a mass is moving,we also change its momentum. Change in momentum will serve to measure force.lt seems obvious that whatever change in momentum is produced by a force, twice the force will produce twice the change ,etc.i.e. the change is directly proportional to the force. For a given mass,m,change of momentum ,mv,means change of velocity;the change of velocity per unit time is aceeleration,a;the change in momentum per unit time is therefore malf we employ absolute units (poundals or dynes)this can be shown as; Newton's third law of motion states that 'to every action there is an equaI and opposite reaction'.This law recognises the dual aspect of forces It a tooth is pushed by a finger spring ,the spring is also pushed by the tooth,and an eqpal counter force acts towards the spring unti1 the biology of the system intervenes. This dual stress is called pressure. Retracting incisors against posterior segments it is apparent that the reaction of the posterior segments must be equal and opposite to the incisors.In this case the two forces act away trom each other,and tG this dual stress we give the name tension.
Chemical aspects of human plaque and enamel
(University of the Western Cape, 1982) Grobler, Sias Renier; van Wyk, C.W
The ideal conditions for the use of hydrazinium sulphate as a reducing agent to determine phosphorus in dental plaque were investigated. When this method was compared to the tin (II) chloride (Kuttner and Cohen, 1927) and ascorbic acid method (Chen, loribara and Warner, 1956),which is generally in use for the measurement of phosphorus in plaque, it was found to have certain advantages. Different ashing techniques were compared, as well as the influence of different acids on wet ashing. The hydrazinium sulphate method could determine as little as 1,8 ~g phosphorus per 50 ml and is recommended for the routine analysis of phosphorus in dental plaque samples with wet ashing. Today phosphorus can be determined, among other methods gravimetrically, titrimetically and spectroscopically (Williams, 1979). Through spectroscopic methods phosphate might be analysed spectrophotometrically by 3 main methods, as molybdophosphoric acid, its reducing product molybdenum blue and the yellow vanadomolybdophosphoric complex (Stuart and Duff, 1980). In addition indirect methods derived from molybdophosphoric acid might also be used (Williams, 1979). When phosphorus is spectrophotometrically determined during the reduction of a phosphomolybdate complex by means of different reducing agents (Kuttner and Cohen, 1927; Chen et aI, 1956; Fiske and Subbarow, 1925 and 1929, Taylor and Miller, 1914; Martin and Doty, 1949; Eibl and Lands, 1969; Vogel, 1961; Boltz and Mellong, 1947; Lazarus and Chou, 1972; Laws and Webley, 1959; Burton and Riley, 1955; Dickman and Bray, 1940), it is necessary to establish the optimum conditions under which the reducing agent, hydrazinium sulphate, can be used. In spite of this, many details about exact experimental procedures are not known (Taylor and Miller, 1914; Vogel, 1961; Boltz and Mellon, 1947). The present investigation is an attempt to establish the ideal conditions for the use of hydrazinium sulphate as a reducing agent during the formation of molybdenum blue (Schirmer et al, 1942) and the effectiveness of the method for the determination of phosphorus in dental plaque by different ashing techniques. The hydrazine method is also compared to that of Chen et al (1956) which is generally in use for plaque phosphate determinations by many authors (Ashley, 1975; Ashley and Wilson, 1976; Kleinberg et al, 1971; Zuniga et al, 1973), as well as to the sometimes used (Dawes and Jenkins, 1962) tin (II) chloride method of Kuttner and Cohen (1927). For the review of many other accepted methods, see Lindberg and Ernster (1956), and Williams (1979). The results are compared to the modified ascorbic acid method (Chen et al, 1956) as well as to the tin (II) chloride method (Kuttner and Cohen, 1927).
A critical investigation of paedodontic education with special reference to graduates of the University of Stellenbosch
(University of Stellenbosch, 1983) Peters, R; Prins, F.X
In South Africa the general dental practitioner has sole re$ponsibility for the provision of child dental care. Accordingly, at Stellenbosch University the objective of the undergraduate paedodontic curriculum is to train a general dental practitioner who is able to provide comprehensive dental care for all categories of children.As this approach is not in accordance with that prevailing in most countries, particularly countries acknowledged to be leaders in the field of 'paedodontics, the objective of this investigation is to examine and test the validity of the philosophy of paedodontic education as it exists in South Africa in general and at the University of Stellenbosch in particular.
Research related to clinical dentistry (1967 - 1983)
(University of Stellenbosch, 1984) Retief, Daniel Hugo; Prins, F. X.
Four spectrophotometric procedures for the analysis of phosphorus were evaluated (1F1). The phosphorus concentrations in saliva and dentine were determined. All four analytical procedures were accurate but the one method was the most sensitive. An acid etch enamel biopsy procedure which was originally developed in Switzerland was modified in our laboratory (#2). It was subsequently shown by other investigators that the modified technique was much more accurate for the determination of the fluoride concentration in enamel than the original procedure.
Trends in skeletal maturation patterns in a Western Cape sample
(University of the Western Cape, 1987) Hansa, Ahmed Ismail; Singh, S.
Skeletal age assessment is not only an important aspect in orthodontic treatment planning, but is also widely used in forensic medicine and physi cal anthropology. Vari aus studi es have shown that chronological age may be at variance with an individual's biologic age. Current research would seem to indicate that the hand-wrist radiograph provides the most accurate method of assessing skeletal age for diagnostic purposes. In recent years the number of patients presenting with malocclusions of a skeletal nature at the University of the Western Cape has increased si gnifi cantly. If it i s accepted that treatment of jaw discrepancies associated with malocclusion is dependent on a large component of dentofacial orthopedics, then by implication it is necessary that a substanti al amount of faci al growth remai ns. The need has therefore arisen for the establishment of skeletal maturation trends in the Western Cape. Skeletal maturity was assessed from hand-wrist radiographs in a sample of 318 Western Cape chi 1dren aged 6 to 16 years for both sexes, utilising the bone specific Tanner-Whitehouse TW-2 scoring system. Data obtai ned from the present study showed a marked di fference in skel etal maturati on trends between femal es of the Western Cape to that of the British norm, while the males showed less divergence. Further, these findings show that in both sexes the epiphyseal bones matured in advance of the TW-standard. Carpal maturation, however, was delayed in the male when compared to the British standard, while that of the female conformed to that of the British standard.
Trends in skeletal maturation patterns in a Western Cape sample
(University of the Western Cape, 1987) Hansa, Ahmed Ismail; Singh, S.
Skeletal age assessment is not only an important aspect in orthodontic treatment planning, but is also widely used in forensic medicine and physi cal anthropology. Vari aus studi es have shown that chronological age may be at variance with an individual's biologic age. Current research would seem to indicate that the hand-wrist radiograph provides the most accurate method of assessing skeletal age for diagnostic purposes. In recent years the number of patients presenting with malocclusions of a skeletal nature at the University of the Western Cape has increased si gnifi cantly. If it i s accepted that treatment of jaw di screpancies associated with malocclusion is dependent on a large component of dentofacial orthopedics, then by implication it is necessary that a substanti al amount of faci al growth remai ns. The need has therefore arisen for the establishment of skeletal maturation trends in the Western Cape. Skeletal maturity was assessed from hand-wrist radiographs in a sample of 318 Western Cape children aged 6 to 16 years for both sexes, utilising the bone specific Tanner-Whitehouse TW-2 scoring system. Data obtai ned from the present study showed a marked difference in skel etal maturati on trends between femal es of the Western Cape to that of the British norm, while the males showed less divergence. Further, these findings show that in both sexes the epiphyseal bones matured in advance of the TW-standard. Carpal maturation, however, was delayed in the male when compared to the British standard, while that of the female conformed to that of the British standard.
The prevalence of occlusal traits in a Western Cape population
(University of Stellenbosch, 1988) Ferguson, Maurice; Moola, M. H.
At the University of the Western Cape there has been a rapid increase in the number of patients requesting orthodontic therapy. The Extent of the problem in this area is not known as no studies have been undertaken in this regard. The purpose of this study was to determine occlusal trends in a Western Cape population, to establish norms with a view to ascertaining treatment needs.
A clinical, study of the protective effects of the application of fissure sealant prior to the direct bonding of orthodontic brackets
(University of the Western Cape, 1990) Sundrum, Dayalan; Samsodien, M G
Orthodontic treatment sometimes has the unfortunate sequela of white spots forming around the margins of the brackets. These white spots or demineralized areas are of concern to the orthodontist ds they may present an aesthetic problem which might require costly restorative work later. AIso at debonding the orthodontist is often faced with the time consuming and arduous task of removing residual composite from the tooth surface. The purpose of this study was to establish whether a fissure sealant used with or without a fluoride containing mouth rinse would prevent white spot formation around orthodontic brackets and whether, coincidently, the use of the fissure sealant moved the fracture site closer to the enamel/resin interface, thereby leaving a clean enamel surface at debonding, saving the orthodontist chairside time. One hundred patients undergoing orthodontic treatment at the Dental Faculty of University of the Western Cape were chosen for this study. The patients were given basic oral hygiene instruction, scaling and polishing and instructed to brush with a fluoride containing dentifrice. The mouth of each patient was divided into four quadrants, with fissure sealant (pelton clear unfilled resin) being applied to two alternate quadrants. The sample was divided into two groups, one of which rinsed with a fluoride containing mouthrinse. There was a significant difference in white spot formation when comparing fissure sealed and non-fissure sealed surfaces. Of the group which rinsed with fluoride mouthrinse, 86t had no white spots or demineralization. Also, the results of this study have shown unequivocally that the prior use of fissure sealant moved the fracture site closer to the enamel/resin interface, thereby leaving Iittle or no residual composite on the enamel surface at debanding.
The prevalence of occlusal traits in a selected Western Cape population
(University of the Western Cape, 1993) Kaka, Joolam; Moola, M. H.
state funded programmes are essential to provide a treatment for the dentally handicapped. To address this need a study was undertaken under the auspices of the Orthodontic Department of the University of the Western Cape to assess the orthodontic needs of children in the Western Cape. The purpose of this study was to determine the occlusal traits of Indian children in the Western Cape and to compare them with samples internationally. The sample consisted of 355 children, 12-14 years old, from schools administered by the House of Delegates. They were examined and recorded according to the methods set out by Baume et al. (1973), and Angle's Classification (1899) with the Dewey- Anderson (1919 and 1960) and EI-Mangoury and Mustafa (1991) modifications The results of this study showed that bilateral molar relationships were: normal in 72.9%; mesial in 5.8% and distal in 15.5% of the children examined. The remaining had an asymmetrical molar relationship (5.8%). The upper incisal area was found to be the most crowded area in the mouth followed by the lower incisal area. Anterior crowding was present in 58.2% and spacing in 12.7% of the sample. The mean overjet was 2.7mm and the mean overbite 2 .1mm. In the posterior segments, open bites accounted for approximately 6.5% and crossbites for 8.3% On the basis of Angle's Classification it was found that 17.1% had a normal occlusion and 54.9% an Angles Class I malocclusion, 16.9% an Angle's Class II malocclusion and 5.5% an Angle's Class III malocclusion. 5.6% of the candidates had an asymmetrical molar relationship. In comparison to other population groups the results suggest that the incidence of some occlusal traits of this Western Cape sample was similar to that of other population groups while some traits were more prevalent. The pattern of the distribution of Angles Classification was also similar to that reported in studies done elsewhere.
Research related to Pathoses of the oral mucosa in South Africa (1964 - 1995)
(University of the Western Cape, 1995) van Wyk, CW; Dreyer, WP
Investigations of pathoses of the oral cavity encompass a relatively wide spectrum of diseases, abnormalities, tumours and tumour-like conditions affecting and occurring in the dental hard tissues and supportive structures, the bony skeleton of the face and the soft tissues of the. mouth. It involves a study of the normal - oral biology - and the abnormal - oral pathology. Oral pathology is a relatively new specialized field of dental science and practice. In South Africa, prior to the nineteen-fifties, research in oral pathology was primarily directed towards dental disease. Two people - Julius Staz of the University of the Witwatersrand and Tony Ockerse of the University of Pretoria - were the doyens in this field and made major contributions to dental science. Staz reported on the status of dental caries and tumorous malformations of teeth and Ockerse on the prevalence and severity of fluorosis in South Africa. During the fifties a second generation of dental surgeons, who were interested in soft tissue, bone and tumour pathology, emerged. They ,were Bertie Cohen, George Baikie, Mervyn Shear and John Lemmer who, at that time, were all from the University of the Witwatersrand. Bertie Cohen later joined the Royal College of Surgeons of England. Mervyn Shear led the field with his research on cysts of the oral cavity. The practice of oral pathology, moulded on anatomical pathology, was established in the early sixties and Mervyn Shear and the author, from the University of Pretoria, became known as oral pathologists. Research at that early stage comprised clinical and histological observations of oral lesions, diseases, tumours and tumour-like conditions. Observation techniques became more sophisticated during the sixties and seventies with the advent of histochemistry and electronmicroscopy. The next major development which blossomed in the seventies and early eighties was the application of epidemiological methods in the study of disease. Epidemiological principles enabled the correct recording of profiles of oral pathoses in the community. Much was learnt about the prevalence and distribution of oral conditions. The application and use of experimental models, especially laboratory animals, became popular in the eighties. Amongst others, a germfree animal unit was established in the Faculty of Dentistry of the University of Stellenbosch enabling workers to study the microbiological aetiology of dental and oral disease. Morphological observations of tumours and mucosal lesions were further enhanced during this period with the development of immunocytochemistry Experimental cell studies by means of cell culture techniques, commenced late in the eighties and was established in the early nineties. These models fostered molecular biology techniques which have become useful tools for the investigation of the aetiology of disease at a cellular and molecular level. At present molecular techniques are also popular in other spheres of oral pathology such as microbiological, immunological and oncological research. The author's first contact with oral pathology as a subject, forming an important and interesting part of dentistry, was the prescribed textbook "Oral and Dental Diseases", 2nd ed., 1951., by HH Stone of the University of Liverpool in the United Kingdom. Subsequently an enduring interest in the subject and research was cultivated by three teachers and colleagues, Ivor Kramer, Robert Bradlow and Mervyn Shear. Ivor Kramer, Professor of Oral Pathology in the Eastman Dental Institute of the University of London was a superb postgraduate teacher of oral pathology, and revelled in research. The Dean of the Institute, Professor Sir Robert Bradlow was a clinician and splendid diagnostician. He correlated the clinical and histopathological features of oral diseases. These two teachers set the course in oral pathology for the author during his postgraduate studies. In the sixties, after a spell at the University of Pretoria, the author joined Professor Mervyn Shear at the University of Witwatersrand. It was here that the author could further his skills of presenting lectures and research papers in an orderely manner and strengthen his love of research. The research carried out by the author reflects to a large extent the development of research in oral pathology in South Africa since 1960.. It includes studies of diseases and lesions of the oral mucosa, the dental hard tissues, tumours of the oral cavity and jaws and forensic odonto-stomatology. To date 139 articles have been published and accepted in scientific journals of which I was the first or co-author. The research presented here, however, comprises only those studies related to pathoses of the oral mucosa as it occurs in South Africa. Fifty-four papers and two abstracts are submitted. The papers are grouped into two divisions which include studies on (I) normal human oral and ectocervical mucosa and (II), those related to pathoses of the oral mucosa. The latter is subdivided into sections on: the profile of lesions of the oral mucosa in the community; cytological, clinical and morphological features of lesions of the oral mucosa; and studies on the aetiology of lesions of the oral mucosa. Each division and section is preceded by a declaration as to the contribution of the author or co-authors and a précis of the aims, objects and research findings. In the introduction of the précis statements are made explaining the aims of the study. These statements are not referenced because they appear in the respective articles.
A comparison of lay and professional opinion on treatment need and treatment outcome
(A comparison of lay and professional opinion on treatment need and treatment outcome, 1997) Vally, Ismail M.; Jones, M.L.
The psychological, social, and cultural aspects of facial and dental attractiveness is an integral part of health care. Lay persons perceptions of facial and dental attractiveness are influenced by many factors including age, gender, geographic location (nationally or international), ethnic status, employment status, cultural differences and social class will effect the social impact of the anomalies. In addition, the public response to dental anomalies will vary according to experience of good health or ill health of the individual, relatives and friends. The perception of malocclusion is often seen differently between orthodontists, patients and lay public. The differing perceptions of patients and dental practitioners may influence the delivery of orthodontic care. It has been reported that 70% of orthodontic treatment is dentist induced and that orthodontic treatment may be undertaken without the patient or parents perceiving a problem with the teeth. (DHSS, Schanscheiff Report, 1986). The thresholds of entry and exit for orthodontic care may be different as perceived by orthodontists and lay persons. Orthodontists may pursue full alignment and perfect occlusion whereas lay persons may accept varying degrees of deviation from normal. This current study has assessed and recorded the differences in opinions of professional orthodontists and lay persons on dento-facial aesthetics, orthodontic treatment need and orthodontic treatment outcome. The study was carried out at the Orthodontic Department, University of Wales, College of Medicine, School of Dentistry. The opinions of 56 lay persons (dental technicians, dental nurses and lay persons not involved in the clinical process) and 97 orthodontists was collected by recording judgements using various patient records as stimuli. For each set of records examined, each member of the panel indicated their opinion using Likert scales. Judgements were made by assessments of 68 study casts in respect of:- * the need for orthodontic treatment on dental health grounds. the need for orthodontic treatment on dental aesthetic grounds. deviation from normal occlusion. the decision whether to treat. ** * In addition, judgements were made on a sample of 50 pairs of outline facial profiles before and after treatment in respect of: * * deviation from normal facial aesthetics comparison of aesthetics pre-treatment and post-treatment. Furthermore, assessments on 50 pairs of pre-treatment and post-treatment study casts in respect of: * * degree of improvement as a result of treatment. acceptability of result. Orthodontists subjective judgements are more reliable than lay persons in their assessments of dental aesthetics, dental health and deviation from normal. The level of agreement for the decision to recommend treatment is similar between orthodontists and lay groups ie. lay persons are as reliable as orthodontists in the decision to recommend treatment. Orthodontists tend to recommend 10 - 12 % more treatment than lay persons. The orthodontist group were more reliable than the lay group in assessing degree of improvement and assessment of outcome. Orthodontists reject approximately 25% of cases deemed acceptable by the lay group. Dental aesthetics appeared to be the most important feature in the assessment of treatment outcome by both orthodontists and lay groups.
A cephalometric and dental analysis of treatment outcomes of unilateral cleft lip and palate children treated at the Red Cross children's hospital
(University of the Western Cape, 2000) Kaskar, Salim; Bellardie, Haydn
This study was a cephalometric and dental investigation of the treatment outcomes of UCLP children treated at the Red Cross Children's Hospital (RCCH) with respect to craniofacial morphology and dental arch relationship. The quality of the outcome for the RCCH group was compared with the outcomes reported for the Six-Centre International Study (Melsted et al., 1992; Mars et al., 1992). The sample consisted of 20 (11 females, 9 males) consecutively treated UCLP children who had cephalometric and dental records taken between the ages of8 to 11years (mean 10.13 ± 1.2 years). The cephalometric analysis described by Melsted et al. (1992) was used to evaluate the skeletal and soft tissue morphology. The quality of the dental arch relationship was measured according to the Gosion Yardstick (Mars et al., 1987). The treatment outcome of children treated at the RCCH was evaluated with respect to craniofacial form and dental arch relationship. When comparing the mean cephalometric skeletal parameters of the RCCH to the six centres in the Eurocleft study, a significant difference was found between the RCCH group and centre D for most of the variables. A significant increase in the upper incisor inclination and maxillary inclination was found in the RCCH patients compared to the European centres. The difference in the soft tissue parameters was limited to the relative protrusion of the nose and the sagittal soft tissue variable sss-ns-pgs. The analysis of the Goslon scores showed a significant difference between the RCCH group and centres C, D, and F. According to the Goslon score, 85% of the RCCH patients had good to satisfactory dental arch relationship, which was comparable to that recorded for centres A(92%), B(89%) and C(94). In conclusion, the results of the cephalometric analysis and the Goslon Yardstick showed a significant difference between the RCCH group and centre D. The GosIon score indicated good quality of the dental arch relationship, which faired favourably with the better centres in the Six Centre Study.
Digitized and computerized recordkeeping in dentistry (Orthodontics) : A Technologically Advanced Alternative to the Analysis and Storage of Study Models
(University of the Western Cape, 2002) Kleinloog, A.D.; Joseph, VP
The research is aimed at investigating and finding alternatives to the physical necessity of producing and storing plaster casts or stone models of the tissues of the mouth. The quest for time and space is universal and the successful management of both results in stress free, financially stable and uncluttered work circumstances. Study models do playa very important role in diagnostics and treatment planning as well as communicating final results in Dentistry, especially in Orthodontic practice. Conventional study models are bulky, fragile, and expensive diagnostic tools produced from impressions taken of the patient's mouth and cast in plaster or stone. The storage of these records creates major space problems, and recalling or retrieving models at some later stage also causes logistical problems. Ideally, the tissues of the mouth could be scanned and from this a 3-D image produced on screen, which could later be milled (machining process of reproducing, explained in Appendix B) if necessary. Three dimensionally accurate, visually pleasing, reproducible, measurable and retrievable records, would be the solution. Computerizing dental records has already revolutionized the industry in the fields of Radiology and written patient data. This information is available at the click of a mouse, and integrated diagnostic tools can be displayed on screen. A thorough investigation of all methods of capturing dental data and 3D images from previously researched and publicized studies was conducted before attempting the latest technology. The final project involved: 1. requesting an introductory and explanatory demonstration on the scanning possibilities in South Africa 2. organizing and attending a demonstration of the laser and contact scanner on study models and impressions. 3. undergoing training in the use of a contact scanner. Computerizing of these results and comparing data derived from analyzing both study models and impressions, manually and digitally. 4. researching and collecting of data with engineering professionals, to establish the validity and viability of this method ( aiming to use uncomplicated, widely accepted and thoroughly applicable basic criteria in all experiments.) 5. evaluation of data statistically by a statistician. Discussion: Digitizing and computerizing of images derived from scanning the models or impressions offers the most attractive alternative for record keeping. Laser scanning disappointed in general due to the relative unavailability in South Africa, the expensive nature of the service elsewhere and limiting factors due to the sensitivity of the laser beam. It is the most promising alternative in future research, because of improved accuracy, higher speed of scanning, uniformity and reproducibility. Contact scanning proved to be available, reliable and adjustable. In most applications, the best results in terms of accuracy and quality of surface finish are obtained using contact scanning. The disadvantage of this method is the time factor and therefore it becomes expensive and economically not viable. The direct scanning of impressions, albeit with laser or contact scanning, remains a scientific and clinical viable option. Conclusion: Digital imaging is still a young technology and many aspects are not yet completely explored. It is a promising technology and its significance is increasing because it opens the door to diagnostic information. Another important development is that the software for digital imaging will become more integrated with other computerized dental applications in the dental office, enabling patient data between different and remote practices to be exchanged more easily. Further progress is not limited by a lack of available image processing tools but rather by our restricted understanding of the various components of diagnostic imaging in dentistry. A Bioengineering exhibition mounted by the University of Munich during a December 2000 conference, displayed a specially adapted CT Scanner that could scan information directly from the mouth. This leads to more possibilities of deriving images without impressions or study casts.
Applicability of tooth size predictions in the mixed dentition analysis in a Kenyan sample
(University of the Western Cape, 2004) Ngesa, James Lwanga; Theunissen, E.T.L; Shaikh, A.B; Dept. of Orthodontics; Faculty of Dentistry
Mixed denticentition space analysis forms a critical aspect of early orthodo However, the applicability of these methods in other ethnic groups has been varied and questionable. The aim of this study is to evaluate the accuracy of the Tanaka and Johnston (1974) and the Moyers (1988) methods in a Kenyan sample. Mesio-distal tooth widths of 131 sets of dental casts obtained from randomly selected patients (50 males; 81 females) attending Kenyatta National Hospital were measured. The mean sum of the four mandibular incisors was used to determine the sum of canine and the two premolars in one quadrant. The predicted values of the mesio-distal widths were statistically compared with their respective actual sum of the canine and premolars of the same quadrants. The results of paired t tests and scatterplots indicated that there were highly significant differences (p<0.003) between actual measurements (Σ 3, 4 & 5) and their accurate among the non-radiographic prediction methods in the mixed dentition analysis in the Kenyan sample. treatment. The two most widely used non-radiographic tooth size prediction methods were derived from populations of Northern European ancestry. predicted values from Moyers (1988) prediction method except at 85% and/or 95% confidence levels. However, Tanaka and Johnston (1974) failed to show any statistically significant differences for either sex and combined sexes at p<0.05. The Tanaka and Johnston (1974) method was the most SAMPLE .
Perception of occlusal appearance in 11 to 12 year-old school children in Nairobi, Kenya
(University of the Western Cape, 2004) Psiwa, Nathan Kitio; Shaikh, A; Ferguson, M; Lalloo, R; Dept. of Orthodontics; Faculty of Dentistry
A public orthodontic system generally is designed to prioritize patients so that those who have the greatest need receive treatment. The aim of this study was to compare the subjective perceptions of the occlusal appearance of 11 to 12 year-old schoolchildren of Nairobi with the modified Aesthetic Component (AC) scale of the Index of Orthodontic Treatment Need (IOTN). The objectives were to assess the children’s perception of their occlusal appearance, categorise the occlusal appearance using the AC scale, by both the children and researcher; and to compare the children’s’ perception and the AC of the IOTN.
A critique of the index of the complexity, outcome and need
(University of the Western Cape, 2005) Ferreira, Dominique Abergail; Ferguson, M; Dept. of Orthodontics; Faculty of Dentistry
The development of a uniform method of epidemiological assessment and grading of malocclusion has been of interest for several decades. Recently, Daniels and Richmond (2000) proposed a new orthodontic index namely the Index of Complexity, Outcome and Need (ICON). Their aim was to develop a single index for assessing treatment inputs and outcomes.The aim of this study was to critique the ICON and to assess to the extent to which each component of the ICON fulfils the ideal requirements of the ideal index as identified in a World Health Organization Report (WHO, 1966). The study was performed in three parts: 1) a gold standard was established to test reliability and validity of the ICON; 2) to assess ease of use and simplicity of the index; 3) and to test the applicability of the index on patients and study casts. The results showed that the ICON identified 25% of the cases as ‘no treatment’, as apposed to the 100% of the gold standard. Validity of the index was shown to be ‘poor’ for complexity (? = 0.2) and degree of improvement (? = 0.34) and ‘excellent’ for outcome. Reliability was high for all the components except for treatment need (? = 0.63). This study concluded that except for complexity and degree of improvement, the index performed well with respects to reliability, validity (of treatment outcome), ease of use and simplicity and applicability to patient and study casts.
Assessment of tooth movement in the maxilla during orthodontic treatment using digital recording of orthodontic study model surface contours
(University of the Western Cape, 2006) Harris, Angela Manbre Poulter; Nortje, C.J.; Wood, R.E.; Dept. of Orthodontics; Faculty of Dentistry
The aim of this project was to measure changes in dimension of the first three primary rugae and to evaluate tooth movement in the maxilla during orthodontic treatment in patients treated with and without premolar extractions.
Incidence, trends of prevalence and pathological spectrum of head and neck lymphomas at national health laboratory services- Tygerberg
(University of the Western Cape, 2007) Chetty, Manogari; Hille, JJ; Bezuidenhout, J
MChD (Oral Pathology) minithesis, Department of Oral and Maxillofacial Pathology, Faculty of Dentistry, University of Western Cape Among malignant lesions, lymphoma ranks second only to squamous cell carcinoma in frequency of occurrence in the head and neck. Lymphomas in HIV patients' are second in frequency to Kaposi's sarcoma as AIDS-defining tumours. About 50% of lymphomas in HIV patients are extranodal and more than half of these occur in the head and neck area. The number, variety and diagnostic complexity of lymphoma cases that have primarily arisen in the head and neck region has steadily increased in the surgical pathology service of the National Health Laboratory Services (NHLS) - Tygerberg. This observation is particularly relevant in the context of increasing HIV infection rates in the population of South Africa as demonstrated by a study in 2006 conducted by the Medical Research Council of South Africa. This is a retrospective study using the records of cases of head and neck lymphomas diagnosed at NHLS-Tygerberg over the last five years. The aim of this study is to investigate the prevalence of head and neck lymphomas (HNL) at NHLS-Tygerberg from January 2002 to December 2006. The objective of this study is to determine the frequency and types of HNL and to determine, if possible, an association between the incidence of HNL and the HIV status of the patients. Trends of prevalence in terms of gender, referral centres, HIV status, age of patients and site of presentation are also examined. The results of this study show an increase in the number of patients with HNL from January 2002 to December 2006. A significant increase is noted in the number of HIV positive patients documented each year, from 17% in 2002 to 33% in 2006. Western Cape- urban (WC-U) remains the largest referral center. A notable increase is seen, each year, in the number of patients referred to Tygerberg-NHLS from the Eastern Cape (EC) and Western Cape- rural (WC-R) areas. A significant number of HIV positive patients are referred from the Eastern Cape and Western Cape rural areas. The average age of disease presentation in the HIV positive group of patients is 35 years with the unknown group being 46 years and the HIV negative group being 54 years. The main categories of lymphoma that presented in HIV positive patients are plasmablastic lymphoma (PBL) and diffuse large B-celllymphoma (DLBCL), which together form 56% of cases. 26% of cases are Hodgkin's lymphoma (HL); the second largest group of HNL cases. Burkitt's lymphoma (BL) consists of 8% of cases. 7% of cases are T-cell lymphomas. 3% of cases are Mantle zone lymphomas. No cases of SLL and Follicular lymphomas (FL) are described in this group of patients. DLBCL and HL form 27% each of the cases in patients with a negative HIV status. A significant number of Follicular lymphomas (15%), small lymphocytic lymphoma (SLL) (9%), MALT (7%), and T-cell lymphomas (8%) are identified. No PBL are seen in this group of patients. The incidence of HNL at NHLS-Tygerberg has increased over the last five years. This trend parallels that seen in other developing countries such as Tanzania, Nigeria, Thailand and India. This increase is possibly due to an increase in the number of referrals to our center, an increase in the overall population of the Western Cape, an increase in the number of HIV positive patients and the high incidence of EBV infection in the general population of the Western Cape. Social issues, such as poverty, lack of adequate education, female dependence on partners, rural communities and the non-availability of anti-retroviral drugs (ARV) and highly active anti-retroviral therapy (HAART) to most of the population that require these drugs, are considered major contributing factors. A trend is noted in the increased number of female patients diagnosed each year with HNL. A predominance of DLBCL was identified in our series. This is consistent with previous reports and studies on HNL. The number of biologically aggressive lymphomas, such as DLBCL, Plasmablastic and Burkitt's lymphomas diagnosed each year, has also significantly increased. These were prevalent mainly in the HIV positive group of patients who were also younger compared to the HIV negative patients. The documented findings of this study will serve as a guideline for the estimation of head & neck lymphoma burden and risk assessment at NHLS- Tygerberg.
Dental maturation of the permanent mandibular teeth of South African children and the relation to chronological age
(University of Western Cape, 2008) Phillips, Vincent; Nortjie, CJ
Age estimation of the skeletal remains of children can be accomplished by examination of the ossification centres and the fusion of the epiphyseal plates of long bones. Dental age estimation is done by examining the eruption of the deciduous and permanent teeth. Both these methods are inaccurate and are subject to the nutritional status of the individual. A more accurate method of age estimation is by the examination of radiographic images of the developmental stages of the tooth crown and root formation. Two methods of dental age estimation used are those of Moorrees, Fanning and Hunt (1963) (MFH) and that of Demirjian, Goldstein and Tanner (1973) (DGT). These methods were tested on a sample of 913 Tygerberg dental patients; a random mixture of Caucasoid and Khoisanoid children. The MFH method under-estimated the ages of the sample by an average of 0.91 years and the DGT method over-estimated the ages by an average of 0.89 years. Samples of Indian and Negroid children from Kwa-Zulu Natal were tested in a similar manner and the results showed similar under and over-estimation of the ages by these methods. The Negroid children were labelled the Zulu sample. Correction factors were derived for the MFH and DGT methods of dental age estimation when used on Tygerberg, Indian and Zulu children. These correction factors were tested on the samples and found to improve the accuracy of the age estimation methods of MFH and DGT significantly. A second sample group of Tygerberg, Indian and Zulu children were then tested firstly using the standard method of MFH and DGT and the using the correction factors. The results showed that the correction factors improved the age estimation on these samples except in the case of the DGT method on Zulu children. A sample of Xhosa speaking children were added to the two Zulu samples and made an Nguni sample. The Tygerberg samples were combined as were the Indian samples to form data bases for the construction of dental age related tables for Tygerberg, Indian and Nguni children. These tables show that there are distinct differences in the ages at which the teeth develop in the different sample groups and that dental age related tables are necessary for children of different population origins. Statistical analysis of the age related tables from this study (Phillips Tables) show these tables are more accurate in the age estimation of South African children.

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