Faculty of Dentistry

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The Faculty of Dentistry of the University of the Western Cape is a world-class oral health centre committed to the promotion of oral health through the excellence of its learning, services and research.

Electronic theses and dissertations are available in the Electronic Theses and Dissertations Repository.

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Dental caries clinical and experimental investigations
(University of Pretoria, 1947) Ockerse, T
pental caries is the most prevalent of all diseases among civilized peo_ple. ~_n_ol middl~~-~o=~ay with ~full c§rfectly healthy tee!h. From various statistics obtained ffo·m- practically every country in the world, the incidence is estimated to be over 95 per cent. By this is meant that more than 95 ont of every 100 persons suffer or have suffered at some time from one or more carious teeth. Statistics are based mostly on dental examinations of school children, because of the obvious difficulty of examining large groups of adults for dental defects. There is a lamentable lack of reliable and accurate statistics concerning the incidence of dental caries in most civilized countries. Klein and Palmer (1938) reported that the incidence of dental caries (as defined above) among elementary school children in the United States is 95 per cent. Day and Sedwick (1935) found the incidence among Rochester (N.Y.) schoolchildren to be 99 per cent. The final report of the Mixed Committee of the League of Nations of 1937 shows that in Norway, of 25,000 school children examined, only 160 possessed perfect sets of teeth, or 99 per cent. affected by dental caries. Day and Sedwick (1935) state that, in the county of Shropshire in England, 97 per cent. of the children at the age of 12 had dental caries. The Director-General of Health of New Zealand, in .his annual report of 1941, states that of 52,500 children examined, 95 per cent. were affected by caries: In India, Day and Tandan (1940) reported that the incidence of dental caries among urban children in Labore was 94 per cent. In South Africa, Friel and Shaw (1931) found 93 per cent. of urban children suffering from dental caries. Staz (1938) reported that of 300 European adults examined in Johannesburg none showed caries-free mouths.
Die ontwikkeling van die epiteel en keratien in die menslike mondholte: In histologiese, elektronmikroskopiese en histochemiese studie
(University of the Western Cape, 1972) van Wyk, Christian Werner; Weber, H.W.
Histological observations revealed that oral epithelium originated from a single ectodermal layer. As the ectoderm grew so it differentiated into squamous epithelium. The first features of squamous differentiation were noticed at 8 weeks in utero in areas where keratinized mucosae were developing, and these were the changing of cuboidal to cylindrical basal cells and the subsequent growth of prickle cells from these cylindrical basal cells. The prickle cells merged with the existing primitive cells and at no stage could a separate squamous epithelial layer I such as the stratum tritermedium of the epidermis I be observed inside the mouth. At 12 weeks in utero squamous differentiation had reached a stage where acidophilic layers appeared in certain regions on the epithelial layer. The time of appearance of these layers varied from case to case. At this stage most of the primitive characteristics had disappeared from the keratinizing epithelium. Unlike the periderm of the skin which was shed into the amniotic fluid, shedding of primitive epithelial cells from the keratinizing squamous epithelium was not noticeable. Thence, the growth of keratinizing epithelium was followed by an increase of acidophilic layers, the appearance of keratohyaline granules in cells and, in some instances, full keratinization. The latter I however I was almost exclusively confined to the vermilion border of the lip. The squamous epithelium of the lining mucosa, which is unkeratinized I developed at a much slower tempo. It retained its cuboidal-shaped basal cells and the primitive features of the overlying cells were lost only at about 4- 5 months in utero I when squamous differentiation set in. At no stage was the squamous differentiation a prominent feature. At junctions between keratinized and unkeratinized epithelia and epidermis the epithelium exhibited features of both types of epithelia that were being joined. This was especially noticeable at the junction between vermilion epithelium and epidermis, where part of the vermilion epithelium displayed a prominent intermediate type of layer. Similarly, acidophilic layers of keratinizing epithelium merged imperceptibly with the walls of cells of unkeratinizing epithelium, creating a small region of an unkeratinizing type of epithelium with keratinized cells. Thus the development of the oral epithelium is through differentiation and renewal of epithelial cells: the ectodermal layer developes into an epithelial layer which is recognised by its squamous appearance. The subsequent growth is by constant renewal of this differentiated epithelium. The pattern of epithelial development I the appearance of the junctional epithelia and the manner in which acidophilic layers merge with unkeratinized epithelial cells I indicate a unity between these epithelia. According to these developmental features, the epithelium of the mouth and epidermis can be classified into less differentiated and better differentiated, but with a commonbackground for these epithelia. When the formation and the established appearance of keratin in the mouth and on the skin was compared histologically I ultrastructurally and histochemically I a unity between these features became apparent. Ultrastructurally it appeared that keratin consisted basically of 2 cytoplasmic constituents: tonofilaments and a fine granular substance. The tonofilaments were gathered at first into bundles and then broken up into finer tonofibrils. These finer fibrils mixed with a granular ground substance to form a homogenous granular filamentous material. This product can be regarded as a pre-keratin. With the addition of a keratohyaline layer to the process I keratin was formed, Apart from the keratohyaline granules several additional changes took place in cells concerned in this process I whether keratin was formed or not. These changes were flattening of cells, extensive interdigitation between cell walls, disappearance of micro-villi I loss of structure in desmosomes I thickening of cell walls and the disappearance of glycogen from cells. Some of these features were displayed in each of the types of epithelium examined here.
Maturation of the permanent teeth in a Western Cape sample
(1974) Singh, Surandar; Lucchessi, M V
The need for in-depth knowledge of dental emergence and calcification in orthodontic diagnosis and treatment planning cannot be disputed. Serial extractions, treatment timing, bite opening and closing, expansion and various other orthodontic procedures cannot be successfully executed without an in depth knowledge of the calcification and eruption of teeth. Besides its orthodontic implications, dental calcification and eruption plays a significant role in physical anthropology, forensic odontology, endocrinology and nutrition (Demirjian, 1978). Forensic scientists are agreed that teeth constitute the most important and reliable means for determining age from approximately 10 week in utero to old age (Altini, 1983). It is a generally accepted fact that there is no correlation between biological age and chronological age (Prahl-Andersen and Van der Linden, 1972; Demirjian, 1978), an aspect, which will be discussed in further detail later in the review of the literature. Biological age is seen to be a more accurate indicator of an individuals maturity than chronological age (Moorees et al, 1963; Prahl-Andersen and Van der Linden, 1973; Oemirjian et al, 1973). However, allocating a biological age to an individual is not an easy exercise as no definite consensus has, to date, been reached regarding the best method of determining biological age (Moorees et al, 1963; Garn et al, 1967; Demirjian, 1978). Today, many different methods are being used to establish this, for example bone age, height, menarche, circumpubertal growth and dental age.
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
A study of some cultural characteristics and blood serum antibodies: titers 0f enterococci isolated from the mouth and faeces
(1975) Slabbert, J C G; Dreyer, C J
Crevicular epithelium presents no effective barrier to the biologicaJly active constituents of plaque. Moreover, it seems that the production of circulating antibodies, the development of a state of delayed hypersensitivity and the development of immunologicai tolerance all play a part in the pathogenesis of periodontal disease. An investigation was undertaken to study the cultural characteristics of enterococci isolated from the mouth and gut of a group of students, and to determinethe serum antibody titres to these organisms. Enterococci were isolated from faeces and the gingival crevice of 9 male dental students. Blood was obtained from each subject and allowed to clot. The serum was removed and stored at -20 0 C• unt'i l requi• red. Blood serum antibody titres to the bacteria were obtained by the indirect fluorescent antibody technique. In order to investigate for the presence· of antibodies to homologous and heterologous enterococcal strains, each subject's serum was tested against all the strains of enterococci isolated. Higher antibody titres were obtained to oral enterococci than to faecal microorganisms. This investigation suggests that there are either differences in the immunogenic iii potential of oral and faecal streptococci or micro-environmental conditions in the host which favour antibody production to oral streptococci as opposed to streptococci in the gut. There are also differences in the cultural characteristics and bio= chemical reactions of the gut and mouth organisms.
Mandibulo-facial dysostosis - An investigation of the cranio-facial and oral manifestations in South African bantu.
(University of Pretoria, 1975) Seeliger, Joachim Ernst; Knobel, D P
The subject, an adult bantu male with most of the features of the classical syndrome, is subjected to a physical investigation with the - emphasis on the cranio-facial and oral manifestations. The clinical appearance of the facies and head is discussed and the findings correlated with those of the accepted syndrome. Special attention is paid to the oral and dental manifestations and measurements are recorded and compared. A rontgenographic examination is .performed on the cranium, facial bones and the jaws. Utilising the lateral skull radiograph ·(cephalogram), a cephalometric analysis is done of the skull and jaws to determine the development that has occurred.
The handling of undated pig embryos and foetuses as a prelude to histological studies of morphogenesis in the oral region
(University of the Western Cape, 1976) van Rensburg, Barend. Gabriel; van Wyk, C.W.
The author is interested in the morphogenesis of the oral region including the nasopalatine complex. With the intention of undertaking a study of the· embryological development in this area, perusal of available literature failed to reveal a single compreh.ensive description of the reception and handling of embryonic and foetal material, mensuration and preparation for miscroscopy. Human material for embryological study is relatively scarce in· the Republic of South Africa. According to the literature there is, however, a distinct similarity between human and domestic pig development in certain regions, notably the palate. Furthermore, pig embryos and foetuses are available in comparative abundance from sows slaughtered at abattoirs. As a consequence of the above-mentioned factors it was,decided to undertake a -preparatory study in order to firstly evaluate existing methods of handling of embryonic and foetal material and secondly, to statistically evaluate data relating to mass and measurements.'· The aim was to draw a comparison with existing information and to select a sample for investigation. Embryos and foetuses were removed from slaughtered sows in a fresh state and removed to the laboratory immersed in 10 per cent neutral buffered formol saline. In the laboratory foetal membranes were removed, umbilical cords cut and the specimens weighed. They were then placed in Bouin's solution for final fixation and decalcification. Instruments were designed to measure crown-tailroot length, crown-rump length and dorsal profile length. After one day in Bouin's solution all specimens were measured. In order to determine the accuracy of the weighing and measuring procedures ten fixed specimens were weighed and measured on seven consecutive days. Statistical analysis of this data indicated that crown-rump length was the most accurately determinable linear measurement, judged by both the coefficient of variation and the standard deviation. On this basis crown-rump length was chosen as the criterion for selecting the sample to be studied. Correlation between linear measurements and between linear measurements and mass for the entire series showed a very strong positive relationship between all the parameters indicating that a dimensional relationship was maintained during growth. After measuring, the small specimens were embedded whole while larger embryos and foetuses were decapitated. A method was described for trimming and embedding these heads in such a way that subsequent sectioning would take place in a standardised transverse plane. In larger specimens this procedure had to be delayed until demineralization had taken place. Conclusions based on a consideration of data for the entire population included the following: 1. The mean number of specimens per litter was 6,475. 2. The number of pigs per litter stayed relatively constant throughout the period of gestation. 3. Mass showed a greater intra-litter variation than any of the three linear measurements recorded. 4. Relatively, lengths appeared to vary less in older than in younger Ldtt.ers-, irrespective of litter size
Pre and Postnatal growth and development of the Mandible
(University of the Western Cape, 1977) Bibby, R.E; Bibby, R.E
This paper has attempted to describe the prenatal development of the mandible in humans and ita postnatal growth. The various theories of how this growth occurs have been described including the historical work by Brash, the' classical theory', .. which includes a section on the controversy regarding the term' growth centre' and its application to the mandibular condyle. Bjork's investigations using the implant method have been covered. This method allowed him to superimpose the mandibles in a longi tudinal growth study with more ease and accuracy than was formerly possible.Note that no mention is made in this paper of the error due to magni~cation changes in the radiographs resul~ing from the growth itself. Enlow's theory ,including his ideas on relocation,cortical drift,reversal etc. based on the morphology of the mandible are covered. The functional theory of Moss'which has many supporters and is perhaps one of the strongest theories is included with a further section on the role function plays The other main theory described is the theory of arcial growth is covered by Ricketts. The chin is a characteristic of Man and a short section will be found about its development Nowadays we are using prediction of the growth of an individual as an intgral part of our treatment plan in orthodontics .I have attempted to describe the structural features of acephalo metric radiograph which are our guidelines for prediction I have included at the end a short part about investigations using hormones to study their role in development.This only scratches the surface of the many hormonal studies carried out but serves to show another side of research concerning the development of the mandible.
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.
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 survey of the oral health status of the institutionalised elderly white people in the Cape Peninsula area of the Republic of South Africa
(University of the Western Cape, 1979) Watermeyer, Gert Johannes Jurgens; Thomas, C.J.
Aging is a biological process under the influence of genetic and pathological factors wh ich can be more or less advanced in different individuals with the same, chronological age. Silverman (1961) defined age as a three-dimensional phenomenon wherein there is a constant interaction between chronologie age, physiologic age and psychologic age. Vinton (1964) also points out that there are physiologic, pathologic, psychologic and sociologic changes which are unique to the latter span of life. These changes are not synonomous with illness as long as they fall within the physiologic limits of normality. If these limits are exceeded the changes are pathological in character. Age is a phase of life which brings about changed circumstances and a new pattern of life which must be adapted to and accepted. This may necessitate an invironmental change which causes a loss of friends and social standing and may bring about a feeling of insecurity in some people, suppressing the incentive to live for the future. To counter these emotions it is imper~tive to create a quality of life in which the aged can be productive within the limits of their physical abilities and which will give them the assurance that they are still needed by society. Life expectancy is determined by the circumstances under which people live. The average age of life expectancy during the Roman period and the Middle Ages was 25 to 30 years; today it is 70 years (Sharry 1974). Nature normally maintains an equilibrium between young and old so that each can provide for the other's needs. Modern science and technology however have upset that balance and brought about new developments in medicine ich have succeeded in increasin and reducin infant mortality, causing the ectancy explosion. This has brought about a situatiop where 10 million humans are born and only 3 million die every month; thus the inflow into life far exceeds the outflow and there is consequently a global increase of 80 million people per year. At this rate the world population will double itself by the end of this century (Pistorius 1978). Birth control has been encouraged as a counter measure to this and the result has been a marked drop in the birth rate, especially in the more advanced countries of the world. This changing relationship between the birth and death rates is referred to as the population-shift. In the U.S.A. 4% of the total population was over the age of 65 years at the beginning of this century. In 1975 the figure was 10% and at the present rate of population-shift will be 20% by the end of this century (Winkler 1977). In England and Wales 6% of the total population was over the age of 65 years in 1931, 10% in 1951 and 12% in 1962. In Scotland 7% was over the age of 65 years in 1931, 9% in 1951 and 10% in 1962 (Storer 1965). In Canada 4,8% of the total population was over the age of 65 years in 1921 and 7,8% in 1971. The average life expectancy was 50 years in 1900 and 70 years in 1960 (Sherman 1970). This pattern of change is also evident in the Republic of South Atrica but there is a marked variation in the different ethnic groups (White, Asian, Coloureds and Blacks) making up the South African population.
Mondbiologie
(University of the Western Cape, 1980) Jansen van Rensburg, B.G; Prins, F.X.
Mondbiologie as onafhanklike vak in die Republiek van Suid-Afrika het die eerste babatreë geneem op 'n senaatsvergadering van die Universiteit van Stellenbosch op 26 Maart 1971 toe die instelling van 'n Departement Mondbiologie goedgekeur is. Die skrywer is op 1 Januarie 1972 aangestel as hoof van die nuutgestigte departement in die Fakulteit Tandheelkunde aan die Universiteit van Stellenbosch. Die ontwikkeling van die vak, veral aan Afrikaanse universiteite, is in die verlede geknel deur die afwesigheid van Afrikaanse handboeke en, in steeds groeiende mate, deur die styging van die pryse van boeke. 'n Verdere remmende faktor is dat geen enkele bestaande handboek 'n oorsig gee van die meeste aspekte van mondbiologie nie. Die motivering vir die opstel van hierdie boeke (Deel I en Deel II) lê daarin dat dit wenslik is dat 'n Afrikaanstalige handleiding in die vak bestaan. Hierdie boeke het hulontstaan gehad in lesingsaantekeninge wat die skrywer oor baie jare saamgestel en probeer verbeter het. In die opstel hiervan is gepoog om materiaal uit verskillende bronne te versamel. Die leser sal gou agterkom dat geen spesifieke verwysings in die hoofinhoud aangegee word nie, maar wel algemene verwysings aan die einde van elke hoofstuk. Ook aan die einde van elke hoofstuk is 'n lys vrae •. Daar word van studente verwag om die vrae uit te werk, hoofsaaklik met behulp van hierdie handleiding en, indien nodig, met verwysing na bronne wat genoem word en in die tandheelkundebiblioteek beskikbaar is. Die inhoud van Boek I dien as inleiding tot mondbiologie en handel hoof= saaklik oor algemene aspekte van embriologie, fisiologie, makro- en mikroanatomie van die mond, sy inhoud en die sisteme wat daarmee verband hou. Die skrywer voel dat hierdie kennis 'n voorvereiste is vir 'n meer toe= gepaste studie van 'n tand en sy omgewing soos weergegee in Boek II. Soos in alle pionierspogings kom daar waarskynlik foute in hierdie werk voor. Die skrywer spreek by voorbaat sy spyt hieroor uit en wil dit graag onder die aandag van die leser bring dat die onderwerpe geselekteer is om so 'n wye veld soos moontlik te dek met inagneming van die beperkte kursusduur. Mnr. P.F. de Klerk, Senior Onderwyser in Afrikaans aan die Hoërskool D.F. Malan te Bellville, was verantwoordelik vir die taalversorging. Hier=voor is die skrywer opregte dank aan hom verskuldig. Vir haar toegewyde andag aan die tikwerk verbonde aan hierdie boeke wil ek baie graag my innige dank aan mev. C.F. du Toit bring. Mnr. A. Louw, Grafiese Kunste=naar, het die titelbladsye ontwerp. Hiervoor bedank ek hom.
Oral cancer (I.C.O 140-146) in South Africa with special reference to its occurrence among the Cape coloured and Indian people of the Cape Peninsula
(University of the Western Cape, 1980) Breytenbach, Hermanus Steyn; Uys, C.J.
Aangesien 'n nasionale register vir maligniteit nie bestaan waarin informasie ten opsigte van kanker onder die verskillende bevolkings groepe van Suid-Afrika nagegaan kan word nie, kan die verspreidings patroon alleenlik bepaal word deur spesifieke projekte. Die resultaat is dat daar nog nie 'n geheelbeeld vir kanker in Suid-Afrika bestaan nie. Wat mondkanker betref, is kennis fragmentaries. Inligting oor die ver spreiding daarvan onder die Kaapse Kleurlingbevolkingsgroep is beperk en net sekere aspekte daarvan is tot hede uitgelig. Die doel van hierdie studie is om mondkanker na te gaan in die Kaapse Kleurlingbevolkingsgroep wat woonagtig is in die Skiereiland van die Kaap die Goeie Hoop. Met hierdie oogmerk, is alle mondkankergevalle wat in die Groote Schuur- en Tygerberg-hospitale behandel is, van 1970 tot 1975, nagegaan. Bewys wyse van vergelyking en ook om die invloed van eie kultuur en akkulturasie na te gaan, is aandag gegee aan ondkankergevalle van Kleurlinge woonagtig in die Skiereiland en dié in die platteland wat in die Skiereiland behandeling ondergaan het. Verder is vergelykings ook getref tussen die,Kaapse Maleier wat die Moslem-geloof aanhang en die Kaapse Kleurling wat nie hierdie geloof aanhang nie. Die mondkankerpatroon van die Indiërs wat in die Skiereiland woonagtig is, is ook nagegaan. Bewys wyse van vergelyking en ook om die invloed van eie kultuur en akkulturasie na te gaan, is aandag gegee aan mondkankergevalle van Kleurlinge woonagtig in die Skiereiland en dié in die platteland wat in die Skiereiland behandeling ondergaan het. Verder is vergelykings ook getref tussen die,Kaapse Maleier wat die Moslem-geloof aanhang en die Kaapse Kleurling wat nie hierdie geloof aanhang nie. Die mondkankerpatroon van die Indiërs wat in die Skiereiland woonagtig is, is ook nagegaan. Ten slotte is die genoemde groepe se mondkankerpatroon vergelyk met dié gevind onder die ander groepe wat in Suid-Afrika bestudeer is, dié in die res van Afrika en ook met dié in die ander kontinente.
A review of obturating materials and obturation techniques used in current endodontic therapy with special reference to the Western Cape
(University of the Western Cape, 1981) Venter, Johan Adriaan; Naudé, O.A.
A review of current root canal obturating materials and obturation techniques was undertaken. This was prompted by the wide variety of the materials and techniques currently being used in the Western Cape. A questionnaire was circulated to 320 members of the Cape (Western) Branch of the D.A.S.A. A viable return of 54,43% was received and this data was studied to determine the pattern of usage of the different materials and techniques in the sample area. Gutta- percha proved to be the mo~t popular obturating material (64,4X) and the gutta-percha lateral condensation technique was indicated by 32,7% of the respondents as being used by them. The cement sealer employed by most respondents was Endométhasone .(38,2%), followed by Riebler's paste (17,3%) and zinc oxide-eugenol (12,5%). This is contrary to the current teaching at the Dental Faculty of the University of Stellenbosch. An extensive review of the literature on obturating mater ials and techniques was undertaken with consideration to the composition and the physical, chemical and sealing properties of the materials being gi ven. Adverse tissue reacti ons caused by the different materials were reviewed as were any peculiarities of the root canal obturation technique. The expected success or failure rates of relevant techniques were considered as well as their advantages and disadvantages. In conclusion certain recommendations as to viable changes to the present endodontic curriculum of the Dental Faculty, University of Stellenbosch are made, based on information revealed by this study.
Entrepreneural trends in health care delivery: The development of retail dentistry and freestanding ambulatory services
(University of the Western Cape, 1982) Trauner, J.B; Trauner, J.B
In the 1970s, traditional delivery patterns in medicine and dentistry began to change as health care professionals sought out new ways to attract patients and to increase practice earnings. Anesthesiologists and surgeons began to build freestanding surgical facilities in competition with local hospitals.1 Physicians trained in emergency or primary medicine established urgent care centers along well-trafficked thoroughfares and catered to patients usually seen in hospital emergency rooms. And, beginning in 1977, dentists began to establish high-volume offices in shopping malls and within the confines of drug, discount, and department. store operations. While the growth of independently owned, non-hospital affiliated surgery centers dates .back to the early 1970s, the major impetus for development of urgent eire centers and retail dental offices was the lifting of restrictions on use of advertising by health professionals. Until 1977, the ethical codes of most medical and dental associations prohibited advertising by their members and these codes had.been incorporated into state licensing requirements. Then in 1977, the U.S. Supreme Court decision in Bates Y. State Bar of Arizona (433 U.S. 350) paved the way for professional advertising. For the first time, health professionals could experiment freely with neM practice forms and use standard marketing techniques to attract potential patients. A new generation of entrepreneurial professionals established medical and dental offices with expanded hours of service and ·drop-in" (non-scheduled) visits to meet the needs of an increasingly mobile populationi some began to rely upon price advertising, introductory offers, and discount coupons. while others began to adopt trade names and develop franchising programs to increase their market visibility. Obviously these new developments were not ignored by local physicians and dentists--or by their professional associations. In states where advertising was regulated under medical or dental practice acts, professional associations monitored advertising copy and reported infractions to state licensing boardsi in states with minimal restrictions on advertising. physicians and dentists began to clamor for new guidelines. Two areas of heated controversy related to advertising of fees (including use of discounts) and the development of fictitious trade names. Another point of conflict involved expanded duties for para-professionals, particularly in dentistry where activities of hygienists and auxiliaries had been narrowly defined by many state licensing boards. In the case of freestanding emergency/urgent care facilities, the overriding issue was how they should be defined and regulated. For instance, should freestanding centers be required to have the same equipment and capabilities as hospital-based emergency facilities? Should they be integrated into local or regional emergency medical service (EMS) systems? To the extent that they were viewed as ·clinics· or ·institutional facilities"--rather than freestanding medical offices--they could be made subject to state licensing restrictions and to the Certificate of Need (CON) planning process mandated by the National Health Planning and Resources Development Act (P.L. 93-641). In the case of freestanding, independently owned surgery centers, the primary opposition came from the hospital industry; in states where freestanding facilities were required to be licensed and/or undergo CON review, the hospital industry regularly took an opposing position, arguing that additional surgical facilities would compound the problem of excess capacity within the health ' care system.
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).
An osteo-radiographic study of the mandibular canal
(1982) erman, Neill Julian S; Nortjé, C.J.
Even though the mandibular nerve is of great importance to the dentist, very little research on the course of the nerve and the relationship of the mandibular canal to the adjacent anatomical structures has been carried out. From the. literature, it appears that the lateral ramus prominence (L.R.P.),or antilingula, is found to be present in from 50% to 100% of cases and is situated anterior and superior to the mandibular foramen. Most authors are in agreement on the situation of the mandibular foramen. Only one mandibular foramen is described in each ramus. The mandibular canal is described as lying inferior to the teeth. There is no agreement on the possibility of the existence of a second mandibular canal per hemimandible. Concerning the mental foramen, it is accepted that one is found on each side, but a second foramen,as well as accessory foramina, namely, the major and the minor variety, are described. In the horizontal plane, the mental foramen is found at the apex of the second premolar tooth or between the premolar teeth. In the vertical plane, the mental foramen is situated from inferior to the apex of the premolar teeth to halfway between the apex and the crown of the premolar teeth. The mylohyoid groove is converted into a canal in 16% of cases but never commences from within the mandibular canal, according to available literature.
Periodontal disease in an adolescent Caucasian population in South Africa - An epidemiological survey
(University of the Western Cape, 1983) Josephson, Cecil Aubrey; Dreyer, Wynand
The epidemiology of periodontal disease in the Republic of South Africa has received only scant attention in the past and consequently the available information is limited. The present study was therefore planned with the primary goal being to establish base-line information regarding periodontal disease in a portion of the population. The adolescent age group was selected as the target for the survey in that destructive periodontal disease (periodontitis) probably commences in many instances during the teenage years and therefore the group would be the one most likely to derive maximum benefit from preventive care and simple treatment measures which could be realistically provided by existing community dental health services. To translate the result into practicality a simple method of treatment needs estimation was also incorporated. In view of the diverse nature of the inhabitants of the Republic of South Africa and in keep with previously conducted studies, the presedt survey was confined to a single ethnic group. The population comprised all 3 .684 white pupils in Standard VIII attending the 34 schools in the Cape Peninsula during 1977. A random sample of 500 was selected for investigation. The average age of the sample was 15 years 9 months and the two sexes were equally represented. Only 7,2% were classified in the lower grade socio-economic class and thus were considered not to have a significant effect on the results. METHOD A team of three, consisting of the author and two assistants, visited each school. Portable equipment included a reclining chair, lighting, compressed air, and hand instruments. The investigation began with a questionnaire to establish the attitude to and experience of symptoms, prevention, and treatment of periodontal disease within the sample. Each subject was then examined and at each of 12 sites, on the 8 incisors and 4 first molars, recordings were made of plaque, gingivitis, supragingival calculus, subgingival calculus, and loss of attachment (periodontitis) according to defined criteria. A standard statistical package was used to analyse the recordings. RESULTS The questionnaire: This showed that almost all the subjects (98%) were interested in the prevention and treatment of periodontal disease in order to achieve and maintain oral health. Not with standing this.The overall prevalence of plaque was 97% and the mean Plaque Index (Pl.I) was 0,94 with 75% of the subjects having a mean Pl.I=0,5. The site prevalence data revealed that out of 12 sites, on average, 4 had Pl.I~O, 4 had Pl.I~l, and 4 had Pl.I~2. In the maxilla the molar sites had the higher plaque levels, whilst in the mandible the incisor sites had higher plaque levels. The sex-specific data showed the males to have higher mean plaque levels than the females, but in 50% of sample with a mean PI.I 0,5 to 1,45 there was ) had had any appurtenant treatment. The overall prevalence of plaque was 97% and the mean Plaque Index (Pl.I) was 0,94 with 75% of the subjects having a mean Pl.I=0,5. The site prevalence data revealed that out of 12 sites, on average, 4 had Pl.I~O, 4 had Pl.I~l, nd 4 had Pl.I~2. In the maxilla the molar sites had the higher plaque levels, whilst in the mandible the incisor sites had higher plaque levels. The sex-specific data showed the males to have higher mean plaque levels than the females, but in 50% of sample with a mean PI.I 0,5 to 1,45 there was no difference.
An investigation into the compatibility of some irreversible hydrorocolloid impression materials and dental gypsum products
(University of the Western Cape, 1983) Owen, Christopher Peter; Wildlng, R J C
This was based on a similar procedure described by Morrow et al (1971) but differed ln several respects. By photographing the gypsum casts through a stereomicroscope at constant signification and using a constant light source, It was possible to produce a consistent, photomicrograph. The gypsum casts were photographed with black-and-white flu, and high-contrast prints obtained of the best-reproduced section of the 01050 mm line. These prints were then subjected to an evaluation procedure using four evaluators who gave a score to the quality of reproduction of the line on a rating scale of I to 4. A11 prints were scored three times by each evaluator, and the sums of these three scores were subjected to statistical analysis. The statistical analysis showed this procedure to be consistent, and that it could be expected to be repeatable. On the basis of this analysis, it was found that one alginate was clearly superior to all others, and that it was possibe to distinguish a further group of combinations within the group that reproduced the 0r050 mm line. Some of the alginate materials were treated with fixing solutions of varying concentrations of potassium sulphate and alum. The results obtained were varied, sometimes producing marked improvement, sometimes deterioration ln the surface quality of the subsequent gypsum cases. None of the treated materials could be improved to the extent of equating then with the best of the naturally compatible combinations
The history of dentistry in South Africa since 1900
(University of the Western Cape, 1983) Grob1er, Vilma; van Rensburg, A P J
Nineteenth Century dentists in South Africa were brought under the provision of legislation in Natal and the Transvaal (1896) and the Cape Colony and the Orange Free State (1899). By the end of the Nineteenth Century a group identity had been established and the transition from a craft to a profession completed. From 1900-1958 dental societies were formed. Key dates are 1922 when the South African Dental Society, which became the Dental Society of South Africa (D.A.S.A.) after Incorporation in 1935, was constituted. Collective action by dentists, implemented through the societies, shaped the profession. From 1933-1948 the constitution of the D.A.S.A. was streamlined. The Magna Charta of Dentistry (Act 13, 1928) was enacted defining dentistry and the practice thereof. The Dental Mechanicians Act (1945) protected the mechanician, the dentist and the public against illicit practitioners. The D.A.S.A. initiated the Professional Provident Society for dentists, now extended to include all the professions. In 1936 tbe first National Congress was held, in 1953 the first International Congress, setting a future pattern. The status of the dentist was further improved by obtaining the right to use the courtesy title Dr and by the abolition of the professional licence fee (1938). The earliest .societies set up voluntary clinics for children and the indigent. The Transvaal initiated a provincial scheme for childrens' followed by the other provinces. Dental Services, a fully fledged of Health. dentistry, This evolved into branch of the Department Witwatersrand University established a dental school in 1925, followed by .the Universities of Pretoria, Stellenbosch , Western Cape and Medunsa. Facilities for postgraduate 'study exist at all these institutions. The R.E.D. Fund Aids Research Education and Development in the field of dentistry. The first unofficial Dental Journal was published in 1927, followed by the Official Bulletin (1945-1946) and finally the Official Journal of the D.A.S.A. During the Anglo Boer War the importance of healthy dentitions'for soldiers was first realised. Four conntract dentists att~nded to the British soldiers. The South African dentists served in the Army Dental Corps during the two world wars. Dentistry in South Africa is now on a par with dentistry in any country of the Western world.

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