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Biomedical subjects

C S Teo

Publications and source records attributed to C S Teo.

At least 19 recordsLinked to original sources
PubMed1999

The delivery of BCNU to brain tumors.

This paper reports the development of three-dimensional simulations to study the effect of various factors on the delivery of 1-3-bis(2-chloroethyl)-1-nitrosourea (BCNU) to brain tumors. The study yields information on the efficacy of various delivery methods, and the optimal location of polymer implantation. Two types of drug deliveries, namely, systemic administration and controlled release from polymers, were simulated using fluid dynamics analysis package (FIDAP) to predict the temporal and spatial variation of drug distribution. Polymer-based delivery provides higher mean concentration, longer BCNU exposure time and reduced systemic toxicity than bolus injection. Polymer implanted in the core gives higher concentration of drug in both the core and viable zone than the polymer in the viable zone case. The penetration depth of BCNU is very short. This is because BCNU can get drained out of the system before diffusing to any appreciable distance. Since transvascular permeation is the dominant means of BCNU delivery, the interstitial convection has minor effect because of the extremely small transvascular Peclet number. The reaction of BCNU with brain tissues reduces the drug concentration in all regions and its effect increases with rate constant. The implantation of BCNU/ethylene-vinyl acetate copolymer (EVAc) matrix at the lumen of the viable zone immediately following the surgical removal of 80% of the tumor may be an effective treatment for the chemotherapy of brain tumors. The present study provides a quantitative examination on the working principle of Gliadel wafer for the treatment of brain tumors.

Antineoplastic Agents, Alkylating↗
PubMed1996

A cross-cultural comparison of perceived sources of stress in the dental school environment.

This study compared the perceived sources of stress in the dental school environment between an American and a South East Asian (Singapore) dental school across their entire curricula (D1-D4 years). The dental environmental stress (DES) questionnaire was administered to 137 (98 percent) Singapore dental students and results were compared to a previous study conducted at an American school. Significant differences were found for 12 questionnaire items across the four classes for the American cohort as compared to 13 in the Singapore cohort. While the greatest stressor for Singapore students was completing graduation requirements, American students were most stressed by examinations and grades. The overall perception of stress by Singapore students was higher than for their American counterparts. The primary concern for both cohorts was, however, related to the different areas of their academic courses.

Analysis of Variance↗
PubMed1995

Relation between incisal overjet and traumatic injury: a case control study.

Most previous studies have shown the prevalence of traumatic dental injuries in anterior teeth to increase with increasing overjet. This study identified 36 Singapore schoolchildren, age 7-18 years, from a clinic population of 11,179, who had suffered dental trauma while playing contact or collision sports. A case control group of 36 children, matched for age, sex, race and sporting activities, but who had not suffered dental trauma, was selected from the same clinic population. Both groups were examined and the nature of injuries received, together with overjet measured to the nearest 0.5 mm were determined. The mean overjet for the trauma group was 3.42 +/- 1.45 mm and for the injured group 3.42 +/- 1.33 mm. These means were not statistically different (p = 1.00), neither did the distribution of overjet between the groups differ. These data were not in accord with the majority of studies correlating incisal overjet and dental trauma, and they suggested that overjet was not a positive correlate with traumatic dental injury in Singapore schoolchildren.

Adolescent↗
PubMed1995

A survey of tooth injury experience and attitudes to prevention in a group of Singapore schoolboys.

A survey of 246 boys aged 12-17 years (mean 13.8 years) determined the sports played, dental injury experience, knowledge and usage of and attitudes towards mouthguard wearing. Most played basketball and soccer. Twenty-one suffered 1 injury episode, 7-2 and 10-3 or more tooth injuries. Twenty-six subluxations, 19 fractures and 1 avulsion were reported. The sports with the highest prevalence of dental injury were boxing and wrestling (33%), soccer (20%), and basketball (19%). While 144 (56%) of boys knew about mouthguards, none wore one. Only 64 (25%) would wear a mouthguard if given one. Most dental injuries were minor, but four high-risk sports (> 19% injury prevalence) would justify preventive measures, including education for injury prevention and encouragement of mouthguard use.

Adolescent↗
PubMed1993

Singapore dentists' knowledge, advocacy and utilisation of mouthguards.

A questionnaire was distributed to Singapore Registered Dental Practitioners, seeking demographic details, knowledge of mouthguards in preventing dental injury during contact sport, current attitudes to advice and provision to at-risk patients. 636 questionnaires were posted and 226 valid replies were received. Most dentists believed that mouthguards reduced the prevalence of dental injury in contact sports. Undergraduate education was the primary source of dentists' knowledge. Seventy-four per cent of respondents actively recommended mouthguards, but only 26 per cent made one or more in 1992. Only 3 dentists made more than 10. Twenty-eight per cent were comfortable with their knowledge in this area, and 76 per cent would be willing to assist a public awareness campaign.

Athletic Injuries↗
PubMed1993

Mouthguards: an easy-to-fabricate element of practice preventive programmes.

Mouthguards reduce the prevalence of dental injuries in contact sports. All types are effective, but those which are closely adapted to the teeth are the best retained, most comfortable, and therefore best accepted by sports people. Closely fitting mouthguards can be directly adapted in the mouth or laboratory-made on a stone model of the dental arch. The mouth-formed types can be fitted without professional supervision, but the procedure is often more successful if undertaken or supervised by a dental professional. The mouth forming procedure is quick and involves little material cost compared to the laboratory-made type. These savings can be passed on to patients in the form of lower fees which should encourage the widespread acceptance of mouthguards as a cost-effective preventive measure. Professionally fitted laboratory-made mouthguards are particularly suitable for high risk activities such as boxing, where more specialised protection such as a bimaxillary guard is indicated.

Athletic Injuries↗
PubMed1990

A cross-cultural cross validation of the Dental Fear Survey in South East Asia.

This study was designed as a cross-cultural replication and cross validation of the Dental Fear Survey (DFS) in two groups of Singapore adults: university students and military conscripts. Factor analysis of the DFS in each of these dissimilar samples revealed factor structures that were highly comparable to one another as well as to those obtained in the U.S.A. Behavioral and physiological fear assessment during exposure to simulated dental treatment also showed results comparable to those found in Western cultures. Self report measures were more likely to correlate with other self reports than with physiologic or behavioral measures. Among university students, those who had visited a dentist within the past year had significantly lower DFS scores than those who had avoided dentistry. The fear-avoidance relationship did not hold for military subjects who reported less dental fear overall. It was concluded that the DFS was factorially stable; and therefore, generalizable to this South East Asia culture.

Adolescent↗
PubMed1990

Prevalence of dental fear in young adult Singaporeans.

One-hundred-and-fifteen male military recruits and 176 mostly female first- and second-year students in the National University of Singapore were surveyed regarding their fear of the dentist. Nine of 115 recruits and 36 of 176 university students were classified as having high fear, giving a population prevalence rate between 78 and 208 fearful young adults per 1000 population. Higher educational levels were associated with fear of the dentist. There were no significant racial differences in the prevalence rate in either sample. Higher fear scores were associated with longer intervals between dental visits for the university but not the military population. Efforts are needed to prevent and ameliorate the development of dental fears. Trust and control appear to be major factors associated with dental fears.

Adolescent↗
PubMed1989

Assessment of dental care delivery to institutionalised aged in Singapore.

Evaluating dental care of institutionalised aged presents numerous problems largely associated with communication and cooperation. This study used administrators' assessment to evaluate cost, accessibility, availability, quality, and efficiency of existing arrangements for dental care. In-house dental care had been rated favourably in all aspects although administrators were less satisfied with it. Generally, public dental facilities received 'favourable' ratings for cost, accessibility, and availability, and self-arranged care the least 'favourable'. Administrators encountered the greatest amount of difficulty when assessing quality and efficiency. Administrators' assessment seemed to be consistent with, and reflective of, the strengths and weaknesses of the various arrangements for dental care.

Administrative Personnel↗
PubMed1989

Management of tooth discolouration.

Discolouration of teeth is a commonly seen dental problem which may affect not only facial aesthetics but also patient's self-image and psychological profile. There is an increasing awareness of such discolouration which may be localised or generalised. Restoration and improvement of this clinical problem has also improved with newer clinical techniques and better dental materials. The aetiology of discolouration is considered first, as this forms the basis of treatment modality to be selected. Management principles should clearly be considered with emphasis on patient input and acceptance. This has been enhanced with computer-aided projection of treatment results. The range of treatment modalities has been widened so that each specific problem can be treated with a method which improves final prognosis. The treatment methods are outlined with clinical cases presented as examples.

Crowns↗
PubMed1987

Bonding of teeth.

Discolouration and altered morphology of teeth are clinical problems commonly presented by patients seeking dental treatment. These patients usually complain of poor dental aesthetics, impaired speech as well as adverse psychological effect. Recent advances in the development of tooth-coloured materials, techniques in the application of these materials and treatment of tooth surfaces to accept and retain such materials have made it possible for the aforesaid dental conditions to be corrected by the process of bonding tooth-coloured materials to the teeth affected. The objective of this study was to evaluate the efficacy of bonding these new materials to tooth structure. 60 patients were selected with spacing of teeth ranging from 0.5-3.0 mm in width. Using the acid-etch regime, the tooth surface was prepared to receive a composite material which was applied with light-polymerisation equipment. The clinical evaluation of retention was made after 1, 6, 12 and 24 months. The results showed that overall 89.2% of the composite restoration were still bonded to tooth structure after a 2-year period. This may be seen as a favourable success rate which could be improved with further material and technique advancement. The implications are discussed.

Acid Etching, Dental↗
PubMed1986

Success rate in endodontic therapy--a retrospective study. Part II.

An evaluation of the success and failure in endodontic therapy performed by undergraduate students over a seven year period was made. The success rate was found to be 90.6%. Age and sex had no significant determination on the outcome of treatment. Further observations on other factors that might influence the prognosis of endodontic therapy were made and discussed in this paper.

Adult↗
PubMed1986

Success rate in endodontic therapy--a retrospective study. Part I.

A survey was undertaken to review the success rate of endodontic treatment carried out by the undergraduates of the Dental Faculty, University of Singapore over a seven year period. A recall system resulted in a total of 385 cases which were successfully recalled and reviewed. The survey comprised of two parts:--A) history-taking from the endodontic record charts and B) clinical and radiographic evaluation of the cases. The cases in the survey had a minimum 2-year recall period. The success rate obtained was 90.6% which compared favourably with other studies. Root canals that were underfilled and root-fillings showing satisfactory apical compression were found to be more successful, the results being statistically significant (P less than 0.05). Endodontic therapy in non-vital teeth and a recall period of at least 2 years were also associated with a higher success rate. This paper discusses the overall success rate of endodontic therapy and the success and failure rate in relation to age and sex. The success rate in relation to other factors such as level of root-filling, apical compression and period of recall will be reported in a separate part of this paper.

Adult↗
PubMed1986

Some problems encountered in endodontic radiography.

This retrospective survey highlights some of the problems faced by undergraduate students using the bisecting angle technique in endodontic radiography. The radiographs of maxillary incisors and premolars were observed to suffer from a greater amount of distortion than radiographs of the corresponding mandibular teeth. Further, the presence of rubber dam equipment affected the accuracy of the radiographs, and this was more apparent on the radiographs of the maxillary incisors and premolars compared to the mandibular incisors and premolars. Other problems identified included superimposition, indistinct and missed root apices. Methods to overcome these problems are suggested.

Bicuspid↗
PubMed1986

Professional dental manpower requirements in Singapore--an overview.

Factors affecting professional dental manpower supply are wide-ranging and varied. Currently much attention has been focussed on the number of dentists serving the population. Whilst the difficulties encountered by new graduates in setting up private practice is real, the indicators for manpower need should not depend solely on this factor. Long term considerations of supply and demand factors should be weighed against short term decisions in planning. This paper attempts to examine some of the factors that have a bearing in the demand for dental care and recommendations are made.

Costs and Cost Analysis↗
PubMed1984

Fluoridation of public water supplies in Singapore.

Fluoridation of public water supplies as a means of reducing the prevalence of dental caries was introduced in Singapore in 1956. This paper will describe the fluoridation programme, and discuss its role in the prevention of dental decay. Water fluoridation has been advocated by the World Health Organisation in 1958 when the first report by an expert committee concluded that drinking water containing about 1 ppm. fluoride had a marked caries preventive action, and that controlled fluoridation of drinking water was a practicable and effective public health measure. Today, more than 60 countries serving over 330 million people have drinking water which is fluoridated. In Singapore, public water supplies contain 0.7 ppm. fluoride. The efficacy of this programme is reported in follow-up studies. After ten years, mean dmf/DMF reduction of 34.4% was recorded for seven-year old Chinese school children, and 33.6% for the same age group Malay school children. These results are consistent with world-wide studies which show beneficial reduction in carries level in children by 30-80%. Fluoridation of public water supplies is indicated if there is an efficient system of distribution and when there is a moderate-to-high prevalence of dental caries.

Child↗