Magister Scientiae Dentium - MSc(Dent) (Orthodontics)

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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).
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.
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.
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.
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.
Oral lesions in hiv/aids patients before and after haart treatment
(2009) Masiiwa, Antonette Musara; Naidoo, Sudeshni
The initiation of highly active antiretroviral therapy has shown to result in successful suppression of viral replications followed by an increase in CD4 lymphocytes, a partial recovery of T-cell specific immune responses and decrease susceptibility to opportunistic pathogens. Aim: The aim of the present study was to determine the prevalence of oral lesions in patients before and after undergoing HAART. Methods: The study design was longitudinal and descriptive, investigating the prevalence of oral lesions presenting in HIV/AIDS patients at baseline, 3 and 6 months after taking HAART. A convenience sample size of 200 participants was targeted. Results: 210 HIV positive patients participated at baseline. At 3 months, 96 (46%) and at 6 months, 52 (25%) were available for review respectively. At baseline 210 HIV positive patients were recruited into the study from three hospitals. Two infectious disease hospitals belonged to the City of Harare and the other is a government hospital. Just over two thirds were female (64.3%) and the age ranged as follows: 21-30 (17%); 31-40 (44%); 41-50 (26% and 51-60 (9%).Discussion: HAART appears to be effective in reducing the prevalence of oral lesions in persons with AIDS likely due to the immunological reconstitution. Oral candidiasis remains the most prevalent oral opportunistic infection in immuno-suppressed individuals and hence its important predictive value for immuno-suppression defined as CD4-cell count level <200/mL of blood. All oral lesions strongly associated with HIV infection with the exception of non-Hodgkin’s lymphoma were diagnosed at baseline. CD4 cell count level increased after initiation of HAART. T-lymphocytes that are formed after the introduction of HAART may not provide sufficient protection against some lesions like parotid gland disease and HPV conditions (planar warts). HAART failure was detected in some patients who had negative CD4-cell count at 6 months compared to the baseline parameters. Conclusions: HIV-positive patients experience oral pain during the course of their disease, eating, drinking and swallowing. Further longitudinal studies are required in order to ascertain the prevalence of these lesions at three and six months and the effect of HAART.
Factors influencing sorption, solubility and cytotoxicity of a heat cured denture base polymer
(2010) Engelbrecht, Magdalena Aletta; Geerts, G.A.V.M.
Objectives:Substances leaching from denture- base polymers have been associated with cytotoxicity and allergic reactions. This study examined the effect of polishing,mixing ratios, water immersion temperatures and different thicknesses on the sorption and solubility of a heat-polymerized, denture-base polymer. The effect of different water immersion temperatures on the flexural strength of the denture base, was tested as well. The next component of this study, is the testing of the most significant sorption and solubility findings on in vitro cell viability. Materials and Methods:Disc shaped specimens from a heat-polymerized, denture-base polymer (Vertex®) were prepared, based on ISO 1567 specifications for sorption and solubility testing, following the manufacturers’ instructions. The following tests were performed: 1) Sorption and solubility of two groups (n = 12 each) of polished and unpolished discs were established and compared by means of the Mixed procedure; 2) Sorption and solubility of three groups (n = 12 each) with different mixing ratios were compared by means of the Mixed procedure; 3) Four groups (n = 14 each) were immersed in water at different temperatures, sorption and solubility were compared by means of pairwise comparison and the Median test; 4) Specimens with different thicknesses (n = 36) were compared, again, by means of pairwise comparison and the Median test; 5) To test the influence of different water-soaking temperatures on the flexural strength of the disc, strips were prepared from the disc used in test no. 3. The flexural strength was compared, by means of the Median test; 6) To test the influence of no postpolymerization treatment, polishing and water immersion on the cytotoxicity of mouse fibroblast cells, (n = 9) for each test group, were prepared. A preliminary test was performed beforehand, over a period of 24 hours, up to a maximum period of four weeks. The Balb/c 3T3 mouse fibroblast cells were cultured and incubated for 24 hours in Eagles medium. Eluates prepared from the disc and medium without any disc (control) replaced the medium. Cytotoxicity was assessed by MTT-assay. Optical density values were obtained at 24 and 48 hour intervals. The data was analyzed by means of the Means procedure.Results:In the entire thesis, the data was analyzed using SAS on a 0.01 probability level.Between polished and unpolished groups, no significant difference in water sorption (p> 0.01) was found, but there was a difference in solubility (p<0.01).Different mixing ratios did not alter sorption (p = 0.34) or solubility (p = 0.68).However, a difference (p<0.01) in sorption and solubility was found among the different temperature and thickness groups. Soaking the denture base in water at different temperatures did not alter its flexural strength (p = 0.48). Cell viability levels were noted in all the experimental groups in the MTT assay test. The analysis was a two-factor study, with one factor being the group, and the other, being time. The interaction between these factors was found to be significant, indicating that the effect of the groups varied by time (and vice versa).Conclusion:The processes of the soaking in warm water and the polishing of a denture-base polymer, reduce its solubility. Therefore, it is recommended that dentures are soaked in warm water before polishing. Within the limits of this study, the mixing ratios may be changed without affecting sorption or solubility. As solubility increases within the increasing denture-base thickness, it is recommended that unnecessarily thick dentures be avoided.Short- and long-term exposure to eluates of a PMMA, has a negative effect on cell viability. For water-stored and polished discs, this effect is time-dependent, with a higher viability for 48 hours’, than for 24 hours eluates. Polishing is associated with lower solubility. At 24 hours, the polished discs, indeed, had a lower cytotoxic effect than the untreated discs: it may be recommended that dentures be polished on the fitting surface as well.The cytotoxic potential of PMMA-eluates appears to fluctuate over time.
Accuracy of orthodontic digital study models
(University of the Western Cape, 2012) Kriel, Earl Ari Mac; Harris, Angela Manbre Poulter; Johannes, K.C.
Background: Plaster study models are routinely used in an Orthodontic practice. With the recent introduction of digital models, an alternative is now available, whereby three dimensional images of models can be analyzed on a computer. Aims and objectives: The aim of this study was to compare the measurements taken on digital models created from scanning the impression, digital models created from scanning the plaster model, and measurements done on the plaster models. The objectives were: Measurement differences between those taken directly on plaster models compared with measurements on digital models created from scanned impressions and digital models created from scanned plaster models. Methods: The study sample was selected from the patient records of one Orthodontist. They consisted of 26 pre-treatment records of patients that were coming for orthodontic treatment. Alginate impressions were taken of the maxillary and the mandibular arches. Each impression was scanned using a 3Shape R700™ scanner. Ortho Analyzer software from 3Shape was used to take the measurements on the digital study models. Within 24 hours plaster study models were cast from the impressions, and were scanned using a 3Shape R700™ scanner. On the plaster models the measurements were done with a MAX-CAL electronic digital calliper. The mesiodistal width as well as intermolar and intercanine width for both the maxillary and mandibular models were recorded.Results and discussion: Box plots used to compare the variability in each of the three measurement methods, suggest that measurements are less variable for Plaster. Plaster measurements for tooth widths were significantly higher (mean 7.79) compared to a mean of 7.74 for Digital Plaster and 7.69 for Digital impression. A mixed model analysis showed no significant difference among methods for arch width. Conclusions: Digital models offer a highly accurate alternative to the plaster models with a high degree of accuracy. The differences between the measurements recorded from the plaster and digital models are likely to be clinically acceptable.
A study to determine the accuracy of Gustafson’s method of age estimation on adult teeth when applied to a sample of the population of the Western Cape
(2013) Chandler, S.; Phillips, Vincent Michael
Teeth are often used to assist in the identification of human bodies after death, especially in cases where the body is badly burned or decomposed, as teeth are usually preserved for a long period of time, even after most of the other tissues of the body have decomposed. Age estimation can play a significant role in order to help narrow down the spectrum of possible identities, for example from the missing person’s database. Gustafson created a method of age estimation, using 6 age-related changes of teeth that occur after the eruption of the dentition. He then compiled a regression line from which the age of a tooth donor could be determined by examining attrition, change of the level of the periodontal attachment, secondary dentine deposition in the pulp, resorption of the root, apposition of cementum and translucency of the root. Gustafson’s method of age estimation was based on Europeans from Sweden. This age estimation method has been used on unidentified individuals at the Salt River and the Tygerberg medicolegal laboratories, but the accuracy is questionable as to whether the method is applicable to the population of the Western Cape. The aim and objectives of this study were to test the accuracy of Gustafson’s method on a sample of adults of known chronological age, to determine the degree of accuracy of the method and to evaluate the consistency of the method. Extracted mandibular central and lateral incisors and maxillary central incisors were used in this study. Two examiners independently used Gustafson’s method of age estimation to estimate the ages of the donors of the teeth. This method was found to be inaccurate when applied to a sample of the adult population of the Western Cape.
Influence of orthodontic caregiver behaviour on the perceived satisfaction of patients during orthodontic treatment.
(University of the Western Cape, 2014) Du Raan, Frederick Johannes; Harris, Angela Manbre Poulter; Hudson, A.
Influence of orthodontic caregiver behaviour on the perceived satisfaction of patients during orthodontic treatment. Dr. F.J. du Raan M.Sc. (Orthodontics) thesis, Department of Orthodontics, University of the Western Cape. In this thesis I interviewed patients that are busy with orthodontic treatment, as well as those that have undergone orthodontic treatment at the department of Orthodontics at the University of the Western Cape, with the aid of four questionnaires. Patients completed questionnaires to provide general and demographic information, quantify their satisfaction with the orthodontic treatment process, their perception of the orthodontic clinician's behavioural traits and lastly they completed the NEO-FFI personality questionnaire to determine their own personality profile. All these questionnaires were used in previous studies, or they were slightly modified to be applicable to orthodontics. The information gained was used to determine if there are correlations between the patient’s perceived satisfaction of the treatment process with patient specific treatment variables (as acquired from the General information and Demographics Questionnaire ), demographic factors, clinician's behavioural traits and patient specific personality traits and any combination of the above mentioned. We wanted to determine which behavioural traits of the orthodontic caregiver influences the perceived satisfaction with the treatment to the greatest extent. Furthermore, we wanted to determine if certain personality traits of the patients would influence their perceived satisfaction with the treatment process or their perception of the clinician's behavioural traits. The only aspect from the General Information and Demographics Questionnaire that had any correlation to satisfaction with the treatment process or the perception of the clinician's behavioural traits, was whether the patient was treated by a single registrar or multiple registrars. Patients treated by multiple clinicians had a lower average score for satisfaction and orthodontist behaviour. Results from the study shows that all the clinician's behavioural traits do have statistically significant influence on the perceived satisfaction with the treatment process, but certain behavioural traits have a greater influence. Result showed Empathy and Care to have the strongest influence on perceived satisfaction, whereas Motivation has the lowest influence. The NEO-FFI personality questionnaire was used to register each patient's personality profile. Scoring for the following personality traits created the personality profile: Neuroticism, Extraversion, and Openness to Experience, Conscientiousness and Agreeableness. Patient personality profiles were shown to have no significant influence on the patient's perceived satisfaction with the treatment process.Neuroticism was shown to have a weak negative correlation with the Professionalism sub-category of the Orthodontic Clinician Behaviour Questionnaire. Conscientiousness has been shown to have a weak positive correlation with all categories of the Orthodontic Clinician Behaviour Questionnaire It is put forth by the researcher that more time and effort has to be put into improving all aspects of the clinician's behaviour, as it will positively influence the perceived satisfaction of the orthodontic treatment process.Even though there are no significant correlations, patients needs to be screened to determine their personality profiles, as this may lead to slight improved scoring on certain behavioural aspects which may in turn lead to greater patient satisfaction. It may be especially worthwhile to recognise the neurotic patient and treat them on a more personal level, as this may improve their overall satisfaction.
The perceived and normative orthodontic treatment need of a group of South African children
(University of the Western Cape, 2015) Rampersadh, Yuvthi; Harris, Angela Manbre Poulter; Barrie, Robert
Introduction: Improvement of aesthetics is often the reason patients seek orthodontic treatment. The ability to accurately assess aesthetic treatment need from the viewpoint of the patient is necessary. The threshold for orthodontic treatment is not constant in all countries and no previous attempts to determine this threshold has been made in South Africa. By ensuring that patient’s perceptions of treatment need are incorporated into the index chosen to assess perceived need, accurate data can be obtained. Determining perceived need from the patient’s viewpoint is important, and understanding its relationship with perceived need according to the professional, as well as normative need can facilitate better patient communication and management of expectations. Aims: There were three main aims of this study. First, South African children’s perceptions of treatment need according to the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) was assessed to determine if they were similar to those of the dentists who established the threshold, or if the threshold of the grading system should be altered to better suit laypeople’s opinions. Second, the newly established threshold could then be used to determine the perceived needs for orthodontic treatment, and compare them to the normative need of the population. Finally, factors that may influence the perceived needs of the patients such as gender, ethnicity and socio-economic position could be investigated. Methodology: A cross-sectional study on 317 children aged between 11 and 14 years was done. 43.8% were male and 56.2 % were female. The sample was chosen from five schools in the Lekwa District of Mpumalanga using a multi-stage sampling technique. The study population comprised of four groups based on ethnicity; Asian (3%), black (74%), coloured (6%) and white (17%). The socio-economic position (SEP) was determined by Principal Component Analysis of household assets. Societal perceived, subjective perceived and self-perceived needs were assessed using a questionnaire and the child-rated AC of the IOTN. An intra-oral examination was conducted using the AC of the IOTN to assess objective perceived need and the modified Dental Health Component (DHC) of the IOTN to assess normative treatment need. Results: Treatment threshold was determined to be grade 3 of the AC of the IOTN according to societal perceived need of the group of South African children, and was confirmed by self-perceived need. Subjective perceived need for treatment was assessed using the AC grade participants felt best reflected their aesthetic impairment, and was found to be 20.2%, compared to actual self-perceived need of 38.5%. The latter was deduced by comparing the child-rated AC (subjective perceived need) to their perception of treatment need of that grade (societal perceived need). The objective perceived need measured by the examiner-rated AC was 60%. Definite need for orthodontic treatment based on the modified DHC of the IOTN was 41.2%. No significant difference between societal perceived or self-perceived need and gender or socio-economic position was found. White children have lower societal perceived treatment need regarding others’ aesthetic impairment. Conclusion: The treatment threshold grade should be lowered to better represent the societal perceived and self-perceived need of the South African population. Normative need was higher than perceived needs from the patients’ point of view (subjective perceived and self-perceived need), but lower than the perceived need from the professional’s point of view (objective perceived need). Ethnicity was found to have an influence on societal perceived need.
Micro-leakage and Enamel demineralisation : a comparative study of three different adhesive cements
(University of the Western Cape, 2016) Elshami, Marrow; Shaikh, A; Grobler, S
Introduction: Micro-leakage and enamel demineralization is still a major challenge in dental practice. It can lead to formation of demineralization lesions around and beneath the adhesive–enamel interface (Mali et al., 2006). Enamel demineralization adjacent to orthodontic brackets is one of the risks associated with orthodontic treatment. The prevention of demineralization during orthodontic treatment is therefore essential for aesthetic reasons and to circumvent the onset of caries. Aim: To assess micro-leakage and enamel demineralization around orthodontic direct attachments (brackets) using three different orthodontic cements. Materials and methods: In this in-vitro study, intact (non carious) extracted human premolars were used to compare the micro-leakage and enamel demineralization of three different cements (Fuji Ortho LC, Rely X luting 2 and Transbond XT). The dye penetration technique was used to evaluate micro-leakage on extracted human premolars. Micro-hardness testing was performed on 21 teeth to determine enamel demineralization. Sixty teeth were randomly divided into 3 groups of twenty teeth each. Direct attachments were cemented on each tooth using 3 different cements; Fuji Ortho LC (GC Fuji II LC GC Corporation Tokyo, Japan), (group 1), Rely X luting 2 cement (3M ESPE dental product, USA), (group 2), Transbond XT Light Cure (3M Unitek, Monrovia, Calif), (group 3). After the orthodontic direct attachments were fitted, they were exposed to 500 thermo-cycles between 5°C and 55°C, with a dwell time of 15 seconds in a buffered (pH 7) 1% methylene blue dye solution (Grobler et al, 2007). The specimens were viewed under a stereomicroscope (Nikon, Japan) at magnification of 40 times. Photographs of each specimen were taken with a Leica camera (Leica DFC 290 micro-systems, Germany) fitted onto a stereomicroscope. The ACDsee photo editing programme was used to transfer the photographs to a computer to measure the dye penetration along the enamel–adhesive and adhesive–bracket interfaces, both on the gingival and occlusal edge at × 40 magnification. For the demineralization sample, 21 teeth were divided into 3 groups of seven teeth each, where direct attachments were cemented using each of the 3 cements, group 1, Fuji Ortho LC (GC Fuji II LC GC Corporation Tokyo, Japan); group 2, Rely X luting 2 cement (3M ESPE dental product, USA) and group 3, Transbond XT Light Cure (3M Unitek, Monrovia, Calif). A digital hardness tester with Vickers diamond indenter (Zwick RoellIndentec (ZHV; Indentec UK) was used to measure surface micro-hardness of enamel before and after attaching the brackets. Ten indentations were made on the enamel surface of each tooth before bonding the brackets with a 300g load applied for 15 seconds to establish the baseline hardness value. After de-bonding the brackets, the hardness was measured again in the same area as mentioned above to determine the degree of enamel demineralization (softening). Result: The result showed statistically significantly lower levels of micro-leakage for Transbond XT (P= <0.001). The amount of micro-leakage on the margins was significantly higher in the gingival portion (P <0.05) as compared with the occlusal margin. Enamel micro-hardness tests before bonding using the three different cements showed that the variances are not significantly different (Chi-squared = 3.051, df = 2, p-value = 0.218). However, the micro-hardness tests done after bonding and thermo-cycling was statistically significantly different (Chi-squared = 13.435, df = 2, p-value = 0.001). Clearly, the Transbond XT group had less hardness, implying greater demineralization than the Fuji Ortho LC and Rely X luting 2 groups. Two sample t-tests show that mean value for the Fuji Ortho and Rely X luting 2 were not significantly different from each other (t = -0.636, df = 12, p-value = 0.537). The mean value for Transbond XT differed significantly from both the other two means: Transbond XT vs Fuji Ortho LC (t = 3.249, df = 6.9, p-value = 0.014). Transbond XT vs Rely X luting 2 (t = 3.493, df = 6.8, p-value = 0.011). Conclusions: This study showed that Fuji Ortho LC and Rely X luting 2 show more micro-leakage than Transbond XT. However Transbond XT had significant lower micro-leakage, less hardness (greater demineralization) than the Fuji Ortho LC and Rely X luting 2. This may have been due to the fluoride release which significantly reduces demineralization. Therefore the Fuji Ortho LC and Rely X luting 2 may be recommended for prevention of demineralization during orthodontic treatment.
Bond strength of metal orthodontic brackets to all ceramic crowns
(University of the Western Cape, 2016) Ismail, Moosa; Shaikh, Amenah; Grobler, Sias
Aim: The aim of this study was to evaluate, in-vitro, the shear bond strength (SBS) and the resultant failure pattern after debonding of metal orthodontic brackets bonded with TransbondTM XT adhesive resin cement and RelyXTM Unicem 2 self-adhesive resin cement to pre-treated (35% ortho-phosphoric acid and silane coupling agent application) IPS eMax and porcelain veneered zirconia crowns. Material and methodology: A Typhodont maxillary lateral incisor was used and prepared in a conventional manner to receive a full ceramic crown. A CAD (computer aided design)/ CAM (computer aided manufacturing) machine was used to scan the prepared tooth and manufacture 40 IPS eMax crowns and 40 porcelain veneered zirconia crowns. Half the number of IPS eMax crown specimens (ie. 20) and half the number of porcelain veneered zirconia crown specimens (ie. 20) were thermocycled (ie. to mimic thermal changes which occur in the mouth), from 5 to 55o for 500 cycles as recommended by the International Organization for Standardization (ISO 6872, 2008). The remaining 20 IPS eMax crown specimens and 20 porcelain veneered zirconia crown specimens remained new and unexposed to thermal changes. The facial surfaces of all the thermocycled and non-thermocycled crown specimens were then etched. Etching of all the ceramic bonding surfaces was performed by the application of 35 per cent ortho-phosphoric acid liquid for 2 minutes, followed by a thin layer of a ceramic primer. A lateral incisor metal bracket with a bracket base area of 9mm2 (as confirmed by the manufacturer) was bonded to each of the etched and silane treated ceramic crown specimens and separated in the following manner: Group 1: (10 thermocycled, etched and silane treated IPS eMax and 10 thermocycled, etched and silane treated porcelain veneered zirconia crown specimens) RelyX™ Unicem 2 self-adhesive resin cement was used to bond the bracket to the ceramic crown specimens, Group 2: (10 thermocycled, etched and silane treated IPS eMax and 10 thermocycled, etched and silane treated porcelain veneered zirconia crown specimens) Transbond™ XT light cure adhesive primer was first applied onto the bonding surface of the crowns and then Transbond™ XT adhesive resin was used to bond the bracket to the ceramic crown specimens, Group 3: (10 non-thermocycled, etched and silane treated IPS eMax and 10 non-thermocycled, etched and silane treated porcelain veneered zirconia crown specimens) RelyX™ Unicem 2 self-adhesive resin cement was used to bond the bracket to the ceramic crown specimens, Group 4: (10 non-thermocycled, etched and silane treated IPS eMax and 10 non-thermocycled, etched and silane treated porcelain veneered zirconia crown specimens) Transbond™ XT light cure adhesive primer was first applied onto the bonding surface of the crowns and then Transbond™ XT adhesive resin cement was used to bond the bracket to the ceramic crown specimens. After bonding all samples were stored in distilled water for 24 hours before being submitted to the shear bond strength test. Debonding forces in Newtons (N) was determined by using a shear testing machine and converted into Mega Pascals (MPa). Results: The results after debonding were compared. The mean shear bond strength for RelyXTM Unicem 2 self-adhesive resin cement bonded to the all ceramic non-thermocycled crowns (Group 3) ranged from a low of 5.1 MPa (45.5 Newtons) when brackets were bonded to the IPS eMax crowns to a high of 5.8 MPa (51.9 Newtons) when brackets were bonded to the porcelain veneered zirconia crowns. The mean shear bond strength for Transbond XT adhesive resin cement bonded to the all ceramic non-thermocycled crowns (Group 4) ranged from a low of 6.4 MPa (57.3 Newtons) when brackets were bonded to the porcelain veneered zirconia crowns to a high of 8.1 MPa (72.7 Newtons) when brackets were bonded to the IPS eMax crowns. The side by side Box-and-Whisker plots of the shear bond strengths show wide and overlapping dispersions of the crown/adhesive resin combinations which consequently lessen the probability of significant differences between the crown/adhesive resin combinations in all 4 groups. According to the Kruskal-Wallis test (p < 0.05), and the Bonferroni Test the non-thermocycled crown/adhesive resin combinations do not differ significantly. Study of the mean ARI (Adhesive Remnant Index) values for the non-thermocycled crown/adhesive combinations shows that brackets bonded with Rely-XTM Unicem 2 to non-thermocycled porcelain veneered zirconia crowns failed entirely at the ceramic/adhesive interface and for all the other non-thermocycled ceramic/adhesive combinations most of the failures of the bond (70%) occurred at the bracket/adhesive interface, ie. cohesive fractures within the composite resin. No cohesive fractures of the porcelain crowns were noted. The results of the thermocycled groups (Group 1 and Group 2) show the TransbondTM XT/non-thermocycled IPS eMax crown combination yielded the highest overall mean shear bond strength of 8.1 MPa (72.7 Newtons) but dropped to a mean shear bond strength of 5.1 MPa (46.1 Newtons) (36.4% drop in shear bond strength) when the crowns were thermocycled prior to bonding. The TransbondTM XT/non-thermocycled porcelain veneerd zirconia crown combination yielded the second highest overall mean shear bond strength of 6.4 MPa (57.3 Newtons) and dropped to a mean shear bond strength of 5.1 MPa (45.8 Newtons) (19.3% drop in shear bond strength) when the crowns were thermocycled prior to bonding. The RelyXTM Unicem 2/non-thermocycled porcelain veneered zirconia crown combination yielded the third highest overall mean shear bond strength of 5.8 MPa (51.9 Newtons) but dropped significantly to a mean shear bond strength of 3.2 MPa (29.1 Newtons) (a significant 43.8% drop in shear bond strength) when the crowns were thermocycled prior to bonding. Lastly, the RelyXTM Unicem 2/non-thermocycled IPS eMax crown combination yielded the fourth highest mean shear bond strength of 5.1MPa (45.5 Newtons) but dropped to a mean shear bond strength of 4.9 MPa (44.5 Newtons) (a drop in shear bond strength of only 3%) when the crowns were thermocyled prior to bonding. Relaxing the significance level (p-value) somewhat demonstrates the negative influence of thermocycling on the shear bond strength of the crown/adhesive combinations. The non-thermocycled all ceramic crown/adhesive combinations showed mean ARI values of between 1.3 and 2.1 indicating cohesive fractures within the composite resin and efficient bonding of the adhesive material to the porcelain surface. However, all the thermocycled all ceramic crown/adhesive treatment combinations showed mean ARI values of between 0 and 0.8 indicating a bond failure between adhesive and porcelain and highlighting the negative influence of thermocycling on bond strength of both adhesive resin cements. Conclusion: Within the limitations of this study, it can be concluded that: 1.There was no significant difference in the shear bond strengths of metal orthodontic brackets bonded with RelyXTM Unicem 2 self-adhesive resin cement and metal orthodontic brackets bonded with TransbondTM XT adhesive resin cement to IPS eMax and porcelain-veneered zirconia crowns which were conditioned with 35 % phosphoric acid and a silane coupling agent. 2. Conditioning the porcelain surface with 35% phosphoric acid and a silane coupling agent (which is safer to use than Hydrofluoric acid) is sufficient for bonding metal orthodontic brackets to all ceramic crowns, and should make it simpler for clinicians to remove the remaining adhesive from the porcelain surface after debonding. 3. The negative influence of thermocycling prior to bonding can be seen on shear bond strength values. 4. Most of the failures of the bond occurred at the ceramic/adhesive interface and cohesive fractures within the composite resin. No cohesive fractures of the porcelain crowns were noted.
Orthodontic treatment need in children aged 12-14 years in Mombasa, Kenya
(University of the Western Cape, 2016) Mwang'ombe, Fiona Githua; Shaikh, A.; Elkhadem, A.
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. Satisfaction with appearance of teeth and occlusion as well as peer comparison was investigated. The treatment need and demand was assessed using the modified AC photographs of the IOTN. Altogether, 488 school children (249 girls and 239 boys) assessed their perception of the anterior teeth using a Verbal Descriptor Scale (VDS) and a Visual Analog Scale (VAS) questionnaire. The researcher examined the anterior teeth of the participants and categorised them using the AC of the IOTN. The following results were reported: about two-thirds of the respondents were satisfied with the appearance of their teeth, with the gender difference being statistically significant. About 35% were dissatisfied or very dissatisfied, but reasons for it varied. More than half of the respondents rated their teeth as better than those of their peers and three-quarters were satisfied with their occlusion, the two responses elicited no gender difference. Treatment need was assessed by use of the AC indicated that there was a moderate agreement between researcher and respondents’ in treatment need assessment. The researcher found 36.3% needed treatment against self-perceived need of 30.9%. One-third of the respondents determined by the researcher to 'need treatment', felt 'no need'. There was no statistical gender difference in perceived need for treatment. The selection of ranked photographs of the AC by both researcher and respondents demonstrated skewed distributions towards the 'low ranked' or attractive end of the ranking order irrespective of the state of occlusion. Statistical comparison of the two methods used, namely the VDS and VAS, indicated that the responses were significantly different. Therefore it is suggested that any treatment priority assessment should take perceptions of occlusal appearance. into consideration.
Orthodontic treatment need and demand in the Upington area of the Northern Cape Province
(University of the Western Cape, 2018) Booysen, Jeannette; Harris, Angela
When considering a person's self-esteem, behavioural patterns and personal interactions, the one feature having the most impact is their physical appearance. In an ideal world, every person should have a fair opportunity to reach their full potential in life. Orthodontics can improve a person's quality of life by creating confident smiles and a functional occlusion (Sheiham, 1993). Uncorrected malocclusions can adversely affect one's speech, general health and self-esteem. Improving the general physiological implications malocclusions has on person, may make them more employable and more successful in relationships, creating an overall happier, healthier and more successful community. The more people are offered affordable orthodontic treatment, the more acceptable orthodontic treatment may become. Thus, the perceived benefits of Orthodontic treatment in a population group are Improvement of Oral Health and enhancement of psychosocial welfare. Accurate data on the prevalence, distribution and severity of malocclusion is needed by provincial oral health management. They also need accurate data of the orthodontic treatment need of the children in that specific area. This data is vital for the effective planning of the education, training and deployment of dental workers, as well as the resources and distribution thereof in specific, designated areas (Holtshousen, 1997; So & Tang, 1993). This study's focus was to estimate the prevalence of malocclusion amongst adolescents in Upington area in the Northern Cape, and to determine the need for orthodontic treatment in the area using the Index for Orthodontic Treatment Need (IOTN).
The orthodontic treatment needs in children aged 12-15 years in a school in Khomas region, Namibia
(University of the Western Cape, 2018) Serebe, Catherine; Harris, Angela; Kimmie-Dhansay, Faheema
In modern day dentistry, aesthetics forms an integral part of our social perception almost as much as functionality. Malocclusion has been brought to the forefront of developmental anomalies as it can affect mastication, speech as well as the appearance of the face. Furthermore, pre-pubertal and pubertal changes have compounded existing malocclusions in this growth period thus spiraling the need for orthodontic treatment. Therefore, it is essential to determine the normative and selfperceived need for orthodontic treatment in a population. The epidemiological data collected can be used to facilitate policy changes to manage malocclusion in Khomas, Namibia. Aim: The aim of this study was to determine the orthodontic treatment needs of a population of 12-15 year-old children attending a school in Khomas and to express it as percentages of those with subjective and objective orthodontic treatment need over the whole sample population. The objectives were to find associations between treatment needs and some demographic and socioeconomic factors.
Soft tissue profile changes in patients treated with non-extraction versus second premolar extraction protocols - using the Damon system
(University of the Western Cape, 2018) Julyan, Johan Christian; Harris, Angela
Orthodontic treatment has the ability to improve the aesthetics and the function of patients. In order to create space, orthodontic treatment often requires removal of teeth. The most common teeth removed for orthodontic treatment are the premolars. It has become popular to remove second premolars in certain cases where the soft tissue profile should not be altered. The Damon self-ligating orthodontic system is renowned for not requiring dental extractions in the majority of cases. The effect of extractions on the soft tissue profile of patients, in conjunction with using the Damon system, has therefore not been researched. It is important to understand the effect that orthodontic treatment and extractions can have on the soft tissue profile of patients. This effect can accurately be determined by making use of the soft tissue cephalometric analysis, developed by Dr Reed A. Holdaway in 1983.

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