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Biomedical subjects

J T Chan

Publications and source records attributed to J T Chan.

At least 19 recordsLinked to original sources
PubMed2001

Effect of topical fluoride on retention of pit and fissure sealants.

PURPOSE: The purpose of this study was to evaluate the clinical effect of topical fluoride on retention of light-cured (CLC) and self-cured (CSC) pit and fissure sealants. METHODS: CLC and CSC sealants were placed in vivo on opposite sides of the arch before and after fluoride treatment. A total of 122 sealants were placed on virgin permanent molars and premolars of 16 dental hygiene students enrolled in a two-year program. Sealant retention in both fluoridated and non-fluoridated teeth was evaluated at 6, 12, and 18 month intervals. RESULTS: Overall sealant retention for both fluoridated and non-fluoridated teeth at 6, 12 and 18 months was 68%, 48%, and 49%, respectively. There was a significant difference (p < 0.001) when fluoridated vs. non-fluoridated teeth were compared. Retention was greater on the fluoridated teeth, with respect to the sealant material (CLC-fluoride). Significant differences (p < 0.001) were found when CLC-fluoride and CLC-no fluoride treatment groups were compared. However, no significant differences were found in retention when CSC-fluoride and CSC-no fluoride groups were compared, or when CLC was compared to CSC irrespective of fluoridation. Significant differences (p < 0.0001) were found when sealant retention on molars was compared to premolars--retention of sealants was greater on premolars. CONCLUSION: This study suggests that sealant retention may not be adversely affected by a topical fluoride treatment applied immediately prior to placement.

Acidulated Phosphate Fluoride↗
PubMed2000

Computerisation of accident and emergency departments in Hong Kong.

This article reviews the history and progress of the computerisation of accident and emergency departments in Hong Kong. The Hospital Information System was the first computerisation project to be launched in a public hospital in Hong Kong, when the Princess Margaret Hospital was selected as a pilot site in April 1991. The network infrastructure comprised a central processor that linked to all workstations in the hospital in an integrated network. With the introduction of bar-coding technology and the implementation of an interfaced network, the Accident and Emergency Information System version 1.0 was launched at the Prince of Wales Hospital in March 1993. A Clinical Management System was then piloted at the Accident and Emergency Department of the Alice Ho Miu Ling Nethersole Hospital in December 1997; it contained clinical data of individual patients, including diagnoses, drug treatments, discharge summaries, allergies, and medical histories. Laboratory, diagnostic radiology, and electrocardiography results were also available in this system. With the extensive development of Internet technology within the Hospital Authority, clinical information can now be retrieved in any hospital in a couple of minutes. The availability of important clinical information will be of great help to emergency physicians in the delivery of quality care to patients.

Emergency Service, Hospital↗
PubMed2000

Dental hygienist and patient comparisons of fluoride varnishes to fluoride gels.

PURPOSE: The purpose of this study was to evaluate a fluoride varnish and compare it to fluoride gels in categories including taste, comfort, efficiency, discoloration, moisture control, safety, and ease of application. METHODS: Methods. Twenty-five licensed dental hygienists and 148 patients completed questionnaires comparing fluoride varnish to fluoride gel for the following categories: taste, comfort, efficiency, discoloration, moisture control, and safety. Responses were analyzed using descriptive statistics and a chi-square test. RESULTS: The 25 dental hygienists rated fluoride varnish (Duraphat) superior to fluoride gels in all categories. Eighty-three (56.5%) of the 148 patients reported the varnish application to be more comfortable than gel while 29 (20%) found it the same. In taste comparison, 90 (71.4%) preferred the varnish, while 16 (12.7%) rated it the same. The time required was reported as better for the varnish technique by 59 (50.4%) and equal to the gels by 32 (20.3%). Discoloration of the teeth by the varnish was found not noticeable or not objectionable by 66 (49.3%) and somewhat objectionable or too noticeable for comfort in public by 68 (50.7%). However, 85 (64.3%) reported that they would choose to have the varnish treatment while 33 (25%) would not. Dental hygienist responses on questions 1-4 relative to the number of years in practice were not found to be significantly different. CONCLUSION: The patients and dental hygienists in this study preferred fluoride varnishes to gels. However, since some patients objected to the temporary discoloration, varnishes may not be suitable for everyone.

Attitude of Health Personnel↗
PubMed1997

Avoidable attendance at accident and emergency by the elderly in Hong Kong.

Twenty per cent of Accident and Emergency department attendance by the elderly in a regional hospital in Hong Kong were deemed 'avoidable' by the attending doctors. The 'avoidable' attendants were younger and physically more independent than the appropriate attendants, and more of them were illiterate. Half of them attended the Accident and Emergency department for somatic complaints. Strategies to reduce these 'avoidable' attendances should be formulated.

Aged↗
PubMed1996

Microleakage of a 4-methacryloxyethyl trimellitate anhydride bonding agent with amalgams.

Microleakage contributes to deterioration of materials, recurrent decay, growth of microorganisms at the interface, and postoperative tooth sensitivity. This study examined the microleakage between amalgams and tooth surfaces with a cavity liner, a 4-methacryloxyethyl trimellitate anhydride bonding agent (Amalgambond) and six different types of amalgams. Class 1 cavity preparations in extracted human molars were filled with different combinations of liners and amalgams and were stored at 37 degrees C in physiologic saline solution. After 1 week half of each amalgam restoration was removed. Within the same group the same cavity treatment was performed and the same type of amalgam was packed as before. Microleakage was determined after 2000 thermal cycles. Statistical analysis indicated that Amalgambond significantly reduced microleakage of different amalgams compared with the Copalite-lined and unlined controls. No microleakage was detected at the interface between the existing and replacement amalgams.

Dental Amalgam↗
PubMed1996

Fluoride content in caffeinated, decaffeinated and herbal teas.

The fluoride contents of infusions prepared from 44 different brands and types of teas were measured. Fluoride concentrations ranged from 0.34 to 3.71 ppm (mean = 1.50 ppm) in caffeinated tea infusions, 0.02-0.14 ppm (mean = 0.05 ppm) in herbal tea infusions, and 1.01-5.20 ppm (mean = 3.19) in decaffeinated tea infusions. This is the first report of the fluoride content of decaffeinated teas. The mean fluoride content of decaffeinated tea infusions is significantly (p < 0.01) higher than the corresponding caffeinated tea. The use of mineral water containing a naturally high fluoride level during the process of decaffeination is the most likely explanation of the above observation.

Beverages↗
PubMed1996

Use of in-office fluorides in the Greater Houston area.

The purpose of this study was to determine the types of fluorides and techniques used for the application of in-office fluorides in the Houston area. A telephone survey was conducted using a stratified random sample of 262 dentists. Approximately 39% of the offices contacted chose to respond to the survey. Only one of the 101 dental offices responding was using an ADA approved professional fluoride product and technique: 1.23% APF for 4 minutes. While 41.6% or 42 of the respondents were using 1.23% APF, they were administering the fluoride for 2 minutes or less with the majority (38 out of 42) administering for only 1 minute. The second most number of respondents (35.6%) reported using a dual rinse type product consisting of 0.31% APF and 1.64% SnF2. Of the 101 respondents, 12.8% reported the use of sodium fluoride gels and rinses. Of these 13 respondents, 9 were using 2.0% NaF but for less than the recommended 4 minute application time. The other 4 were using 2.0% rinse which is more appropriate as a weekly-use rinse. The remaining respondents (9.8%) reported the use of a stannous fluoride containing less fluoride than the approved 8.0%. Of these 10 respondents, 3 were using 0.63% SnF2 and 7 were using 0.4% SnF2. One office reported the use of a non-fluoride containing mouthrinse used as an in-office fluoride treatment. This response is not included in the data as it does not qualify as a type of fluoride product.

Acidulated Phosphate Fluoride↗