Rivers are immensely important to human activities such as water supply, navigation, energy gener... more Rivers are immensely important to human activities such as water supply, navigation, energy generation, and agriculture. They are also an important morphodynamic agent of erosion, transport and deposition. Their capacity to transport sediment depends on their hydraulic characteristics and can be predicted by mathematical models. Several mathematical models can be used to compute bed-load transport. Each one is appropriately better for certain conditions. In this paper, we present an application built in Microsoft Excel to compute the bed-load transport in rivers based on the Van Rijn mathematical model. The Van Rijn model is appropriate for rivers transporting sandy sediments in conditions of subcritical fl ow. Hydraulic parameters such as channel slope, stream power, and Reynolds and Froude numbers can be calculated using the application proposed here. The application was tested in the Paraná River and results from the calculations are consistent with data obtained from fi eldwork surveys. The error of the application was only 20%, which shows good agreement of the model with survey values. Modelo Matemático; Microsoft Excel; Rio Paraná.
The aim of this study was to examine the prevalence and experience of early childhood caries amon... more The aim of this study was to examine the prevalence and experience of early childhood caries among 5- to 6-year-old children in Southeast Asia. A literature search was conducted of three electronic databases (PubMed, EMBASE and ISI Web of Science) to identify publications from the years 2006 to 2015. Additional hand searches of government reports and national studies were performed. Both primary and secondary data sources were included in the study. The inclusion criterion was the findings reported on the caries prevalence and/or caries experience in decayed, missing or filled tooth (dmft) or decayed, missing or filled surface (dmfs) scores of 5- to 6-year-old children in Southeast Asian countries. The papers retrieved were assessed by two independent reviewers, and the final decision was made by consensus. The search identified 320 papers for screening; 293 were excluded and 27 full papers were retrieved and reviewed. Of those, 12 were included. Among the countries, variations were...
This practitioner-based clinical trial compared the pain reduction achieved by professional proph... more This practitioner-based clinical trial compared the pain reduction achieved by professional prophylaxis with 8% arginine calcium carbonate (CaCO3) desensitizing paste versus 5% potassium nitrate (KNO3) toothpaste on adult patients with tooth hypersensitivity. All dentists in Hong Kong were invited to join the study. Each participating dentist identified six adult patients with hypersensitive teeth after scaling in the clinic. For each patient, the most hypersensitive tooth was selected. Each hypersensitive tooth was isolated and tested with a blast of compressed cold air delivered from a three-in-one syringe. The patient was then asked to indicate a sensitivity score (SS) from 0 to 10. Three patients received professional prophylaxis with 8% arginine CaCO3 desensitizing paste (Group 1), and the other three received prophylaxis with desensitizing toothpaste containing 5% KNO3 and 1,450 ppm fluoride (Group 2). The teeth were tested for a second time with compressed cold air, and the patients were asked to report the SS again. A non-parametric test was used to analyze the results following a normality test of the SS. A total of 303 patients were recruited by 65 participating dentists. The mean age of the patients was 40.1, and 59% were female. The median pre-treatment SS of Groups 1 and 2 were both 7, whereas the post-treatment SS were 3 and 4, respectively (P < 0.001). The median percentage reductions in sensitivity scores of Groups 1 and 2 were 57.14% and 38.75%, respectively (P < 0.001).
Recent advances in biomaterial science and tissue engineering technology have greatly spurred the... more Recent advances in biomaterial science and tissue engineering technology have greatly spurred the development of regenerative endodontics. This has led to a paradigm shift in endodontic treatment from simply filling the root canal systems with biologically inert materials to restoring the infected dental pulp with functional replacement tissues. Currently, cell transplantation has gained increasing attention as a scientifically valid method for dentin-pulp complex regeneration. This multidisciplinary approach which involves the interplay of three key elements of tissue engineering—stem cells, scaffolds, and signaling molecules—has produced an impressive number of favorable outcomes in preclinical animal studies. Nevertheless, many practical hurdles need to be overcome prior to its application in clinical settings. Apart from the potential health risks of immunological rejection and pathogenic transmission, the lack of a well-established banking system for the isolation and storage o...
Objectives: To describe the associations among spouses and their children regarding their oral he... more Objectives: To describe the associations among spouses and their children regarding their oral health knowledge, attitude and behaviours. Methods: The study population was households with a child attending grade 1 in primary school in Hong Kong. Selected schools in different districts participated. Visits to the students' homes were made. The father and the mother each separately completed a questionnaire on his/her own oral health knowledge, attitude and behaviours. Another questionnaire about the child's oral health behaviour and parents' attitude towards their child's oral health was completed by parents. Spearman's correlation and McNemar's test were used to assess the relationship between father's, mother's, and their child's oral health knowledge, attitude, behaviours. Result: So far, 143 families including 117 fathers, 140 mothers and 143 children participated. Twice daily was the most common frequency for tooth brushing (69%) reported by t...
Objective: To compare the appearance of dentin after application of silver diammine fluoride (SDF... more Objective: To compare the appearance of dentin after application of silver diammine fluoride (SDF) solution to that of dentin after application of SDF solution followed by potassium iodide (KI) solution. Method: Rectangular dentin blocks from root trunks of extracted permanent molars were cut into four blocks each. All blocks were coated with clear varnish except one flat surface of similar size. The 4 dentin blocks from the same tooth were allocated into four different groups randomly. Gp1- Artificial caries lesions (≈200µm deep) created (BHI broth, multi-species cariogenic bacteria, 10 days) + SDF; Gp2-Artificial caries lesion created + SDF + KI; Gp3- immersed in sterilized BHI broth (10 days) + SDF; Gp4- immersed in sterilized BHI broth (10 days) + SDF + KI. Color of the dentin blocks was recorded using PANTONE color sheets and was coded into 1-Light yellow (PANTONE code: 12-0704-TPX/11-0907-TPX); 2-Yellow (1205U/7401U); 3-Light brown/Greyish (4635U/402U); 4-Dark brown/Black (462...
Objective: OHIDL was developed to measure the perceived oral health impacts on daily life. The tr... more Objective: OHIDL was developed to measure the perceived oral health impacts on daily life. The transition scale in OHIDL was used to measure the change in perceived impacts after dental treatment. This study aimed to examine its longitudinal validity. Method: Elderly subjects aged 55 years or above were recruited from four dental clinics in Hong Kong. They were asked to rate the intensity level of 16 items in OHIDL before and after dental treatment. They were also asked to retrospectively rate the transition (change of the intensity) of these items after the treatment. Intensity and transition scores were calculated through summing up the responses. Change score was calculated as the difference between the two intensity scores before and after treatment. The associations of the transition and change scores with the global rating of change were used to evaluate their responsiveness. Result: A total of 176 subjects (mean age: 60.1 years; SD: 8.1) completed the follow-up interviews aft...
Objectives: to describe the influence of oral hygiene and denture wearing on root surface caries ... more Objectives: to describe the influence of oral hygiene and denture wearing on root surface caries in community-dwelling elders in Hong Kong Method: The study population was community-dwelling elders aged over 55 years who had at least 5 teeth with exposed root surfaces and self-care ability for normal daily activities. Ethical approval from IRB was obtained. Subjects were recruited from 12 elderly social centres and they were examined there by one trained examiner using disposable dental mirrors attached to an intra-oral LED light and CPI probes. Status of the expose root surfaces, presence of plaque, and denture status were recorded. A Visible Plaque Index (VPI) score was calculated by dividing the percentage of surfaces with plaque visible to naked eyes by the total number of root surfaces examined. Results: A total of 271 elders and 10866 exposed root surfaces were included in this study. Their mean age was 72.3 years (SD=6.2) and 77% were women. Elders with higher VPI scores had ...
Objective: To explore traditional oral health beliefs and oral health practice among Bulang peopl... more Objective: To explore traditional oral health beliefs and oral health practice among Bulang people, an ethnic minority group who lives in remote villages in Southwest China which is known to have black teeth. Methods: This qualitative study was conducted with ethics approval in 2013 in Yunnan, China where most Bulang people live. The study used a community based participatory method to collect the needed information. Village leaders, chiefs, elders and senior people were invited for a focus group discussion. Questions on traditional oral health beliefs, oral hygiene practice, and traditional therapeutic methods for tackling dental problems were asked. The discussions were video-recorded, transcripts made, and data were extracted. The focus group discussions were repeated in different villages until there was data saturation, i.e. no new information was found. Results: Three focus group discussions with 18 Bulang participants were conducted. They believed their dentition was good if ...
Fluoride varnish was incorporated into clinical dentistry to reduce caries; its use in the U.S. h... more Fluoride varnish was incorporated into clinical dentistry to reduce caries; its use in the U.S. has increased progressively since it was approved by the FDA in 1994. This paper reviewed clinical studies and found that fluoride varnish's effectiveness in caries prevention, ease of application, and safety give it an advantage over other types of topical fluoride treatments (such as gels and rinses) or other caries management methods. As a result, it is regarded as one of the superior topical fluoride agents for young children.
The aim of the present study was to test the presumptive therapeutic effect of chlorhexidine digl... more The aim of the present study was to test the presumptive therapeutic effect of chlorhexidine digluconate in a population with untreated gingivitis and presence of abundant calculus. SETTING AND STUDY DESIGN: Sixty subjects (approximately mean age of 23.4) were recruited from a knitting factory in the Province of Guangdong, People's Republic of China. By applying a double-blind clinical trial design the participants were divided into two groups (Test and Control) and matched according to their mean GI scores. The Test group (n = 20) was assigned to two daily mouthrinses for 6 days per week using 0.12% chlorhexidine digluconate (Peridex). The Control group (n = 40) rinsed twice daily with a placebo solution. All the rinsings were supervised and timed for 45 s. No attempt was made to influence the oral hygiene habits of the participants. Prior to and after 3 months of the supervised rinsing, plaque was scored using the Plaque Index system (PII), and gingivitis was assessed using the criteria of the Gingival Index system (GI). Calculus was scored according to the Calculus Surface Severity Index system (CSSI), and stain was also graded by the Discoloration Index system (DI). After 3 months, the Test group (n = 13) showed significant reduction in mean PII, GI and percentage of gingival bleeding (GB%), while significant increases in mean DI were observed. The improvement in gingival health was observed at all regions with marked reduction in mean GI (from GI = 1.40 to 1.08) and GB% reduction by 24-52%. The proportion of GI = 2 was also reduced significantly from 50-36%. The Control group (n = 23) also showed a decrease in mean PII but significant increases in the mean GI and GB%. Intergroup comparison showed statistically significant differences between mean GI, percentage of gingival bleeding (GB%) and mean DI for the test and control groups after 3 months of supervised rinsing. However, there were no significant intergroup differences for mean PII. In conclusion, there was a significant effect of chlorhexidine on gingivitis, although the effect may be too limited to assure prognostic benefits in the prevention of future disease progression.
Long-term aim is to determine optimum interventions to reduce dental caries in children in disadv... more Long-term aim is to determine optimum interventions to reduce dental caries in children in disadvantaged communities and minimise the effects of exclusion from health care systems, of ethnic diversity, and health inequalities. Generation of initial explanatory models, study protocol and development of two standardised measures. First, to investigate how parental attitudes may impact on their children's oral health-related behaviours and second, to assess how dentists' attitudes may impact on the provision of dental care. Core research team, lead methodologists, 44 consortium members from 18 countries. To complete the development of the questionnaire, the initial set of items was administered to parents (n = 23) with children in nursery schools in Dundee, Scotland and sent to the same parents one week later. A standardised measure examining barriers to providing dental care for children aged 3 to 6 years was developed. 20 dentists working in primary dental care in Scotland co...
The objective of this study was to review orofacial functional impairments among patients followi... more The objective of this study was to review orofacial functional impairments among patients following stroke, including objective and subjective assessment. A structured search strategy was applied to three electronic databases (Pubmed, Embase, and Web of Science) to identify effective papers. Relevant data regarding subjects, method, outcomes, and key findings were extracted from the effective papers and the results were summarized. The initial search yielded 5227 papers, and 18 effective papers (Kappa: 0.971) were in accordance with the inclusion criteria. The patients with stroke consistently showed a decreased lip force, salivary flow rate, and chewing performance compared with the healthy controls. Due to equivocal results gained from the effective papers, the qualitative assessments regarding whether there was any change in masticatory force on the affected side and oral health-related quality of life were inconclusive. Existing evidence highlights a number of compromised orofac...
the baseline parameters were increasing indicating increasing hazard rates from interval 1 to 6. ... more the baseline parameters were increasing indicating increasing hazard rates from interval 1 to 6. Results based on the logistic regression models were similar. In conclusion, the use of the MCMC approach and non-informative prior in a Bayesian framework to mimic the ML estimation in a frequentist approach in multilevel modelling of clustered grouped survival data can be easily applied with the use of the software WinBUGS.
To evaluate the preventive effect of Er:YAG laser (EYL) irradiation followed by silver diamine fl... more To evaluate the preventive effect of Er:YAG laser (EYL) irradiation followed by silver diamine fluoride (SDF) application on dentine with cariogenic biofilm challenge. Twenty-four dentine slices were prepared from extracted sound human third molars. Each slice was cut into four parts for SDF application, followed by EYL irradiation (group SL), SDF application (group S), EYL irradiation (group L) and water (group W). The specimens were subjected to cariogenic biofilm challenge for 12 h, followed by immersion in a buffered remineralising solution containing calcium chloride and sodium hypophosphate for 12 h at 37 °C. Surface morphological changes in the specimens were examined using scanning electronic microscopy. Elemental analysis was performed using energy-dispersive X-ray spectrometry. Micro-mechanical properties were investigated by nanoindentation. The specimen surfaces of groups SL and L showed laser melting contours with narrowed dentinal orifices. Group S showed a partial tubular occlusion. A porous surface was observed in group W, indicating demineralisation. The mean (SD) fluoride weight percentages were 3.93 (0.91), 3.10 (0.61), 0.17 (0.09) and 0.32 (0.07) in groups SL, S, L and W, respectively, (p<0.001; SL, S>L, W). The mean (SD) micro-hardness values in GPa were 1.84 (0.22), 0.49 (0.13), 0.41 (0.11) and 0.30 (0.06) in groups SL, S, L and W, respectively, (p<0.001; SL>S>L, W). The mean (SD) elastic moduli in GPa were 75.1 (7.2), 20.0 (1.3), 24.3 (5.2) and 20.2 (2.8) in groups SL, S, L and W, respectively, (p<0.001; SL>S, L, W). SDF application followed by EYL irradiation on a dentine surface increased its resistance to cariogenic biofilm challenge.
To investigate the inhibitory effects of 38% silver diamine fluoride (SDF) on demineralised denti... more To investigate the inhibitory effects of 38% silver diamine fluoride (SDF) on demineralised dentine. Human dentine blocks were demineralised and allocated to four groups: SF, F, S and W. The blocks in group SF received a topical application of 38% SDF solution (253,900ppm Ag, 44,800ppm F), group F received a 10% sodium fluoride solution (44,800ppm F), group S received a 42% silver nitrate solution (253,900ppm Ag) and group W received deionised water (control). They were subjected to pH cycling using demineralisation solution (pH 5) and remineralisation solution (pH 7) for 8 days. The surface morphology, crystal characteristics, lesion depth and collagen matrix degradation of the specimens were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-CT testing and spectrophotometry with a hydroxyproline assay. The surface morphology under SEM showed evident demineralisation with exposed collagen in groups S and W, but not in group SF. Clusters of granular spherical grains were observed in the cross-sections of specimens in groups SF and F. XRD revealed precipitates of silver chloride in groups SF and S. The mean lesion depths (±SD) of groups SF, F, S and W were 182 ± 32μm, 204 ± 26μm, 259 ± 42μm and 265 ± 40μm, respectively (SDF, F&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;S, W; p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). Groups SF and S had significantly less hydroxyproline liberated from the dentine matrix than groups F and W (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). The use of 38% SDF inhibited demineralisation and preserved collagen from degradation in demineralised dentine. SDF application positively influences dentine remineralization.
A particle swarm optimization (PSO) based algorithm for finding the Pareto solutions of multiobje... more A particle swarm optimization (PSO) based algorithm for finding the Pareto solutions of multiobjective design problems is proposed. To enhance the global searching ability of the available PSOs, a novel formula for updating the particles' velocity and position, as well as the introduction of craziness, are reported. To handle a multiobjective design problem using the improved PSO, a new fitness assignment mechanism is proposed. Moreover, two repositories, together with the age variables for their members, are introduced for storing and selecting the previous best positions of the particle as well as that of its companions. Besides, the use of age variables to enhance the diversity of the solutions is also described. The proposed method is tested on two numerical examples with promising results.
Rivers are immensely important to human activities such as water supply, navigation, energy gener... more Rivers are immensely important to human activities such as water supply, navigation, energy generation, and agriculture. They are also an important morphodynamic agent of erosion, transport and deposition. Their capacity to transport sediment depends on their hydraulic characteristics and can be predicted by mathematical models. Several mathematical models can be used to compute bed-load transport. Each one is appropriately better for certain conditions. In this paper, we present an application built in Microsoft Excel to compute the bed-load transport in rivers based on the Van Rijn mathematical model. The Van Rijn model is appropriate for rivers transporting sandy sediments in conditions of subcritical fl ow. Hydraulic parameters such as channel slope, stream power, and Reynolds and Froude numbers can be calculated using the application proposed here. The application was tested in the Paraná River and results from the calculations are consistent with data obtained from fi eldwork surveys. The error of the application was only 20%, which shows good agreement of the model with survey values. Modelo Matemático; Microsoft Excel; Rio Paraná.
The aim of this study was to examine the prevalence and experience of early childhood caries amon... more The aim of this study was to examine the prevalence and experience of early childhood caries among 5- to 6-year-old children in Southeast Asia. A literature search was conducted of three electronic databases (PubMed, EMBASE and ISI Web of Science) to identify publications from the years 2006 to 2015. Additional hand searches of government reports and national studies were performed. Both primary and secondary data sources were included in the study. The inclusion criterion was the findings reported on the caries prevalence and/or caries experience in decayed, missing or filled tooth (dmft) or decayed, missing or filled surface (dmfs) scores of 5- to 6-year-old children in Southeast Asian countries. The papers retrieved were assessed by two independent reviewers, and the final decision was made by consensus. The search identified 320 papers for screening; 293 were excluded and 27 full papers were retrieved and reviewed. Of those, 12 were included. Among the countries, variations were...
This practitioner-based clinical trial compared the pain reduction achieved by professional proph... more This practitioner-based clinical trial compared the pain reduction achieved by professional prophylaxis with 8% arginine calcium carbonate (CaCO3) desensitizing paste versus 5% potassium nitrate (KNO3) toothpaste on adult patients with tooth hypersensitivity. All dentists in Hong Kong were invited to join the study. Each participating dentist identified six adult patients with hypersensitive teeth after scaling in the clinic. For each patient, the most hypersensitive tooth was selected. Each hypersensitive tooth was isolated and tested with a blast of compressed cold air delivered from a three-in-one syringe. The patient was then asked to indicate a sensitivity score (SS) from 0 to 10. Three patients received professional prophylaxis with 8% arginine CaCO3 desensitizing paste (Group 1), and the other three received prophylaxis with desensitizing toothpaste containing 5% KNO3 and 1,450 ppm fluoride (Group 2). The teeth were tested for a second time with compressed cold air, and the patients were asked to report the SS again. A non-parametric test was used to analyze the results following a normality test of the SS. A total of 303 patients were recruited by 65 participating dentists. The mean age of the patients was 40.1, and 59% were female. The median pre-treatment SS of Groups 1 and 2 were both 7, whereas the post-treatment SS were 3 and 4, respectively (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). The median percentage reductions in sensitivity scores of Groups 1 and 2 were 57.14% and 38.75%, respectively (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001).
Recent advances in biomaterial science and tissue engineering technology have greatly spurred the... more Recent advances in biomaterial science and tissue engineering technology have greatly spurred the development of regenerative endodontics. This has led to a paradigm shift in endodontic treatment from simply filling the root canal systems with biologically inert materials to restoring the infected dental pulp with functional replacement tissues. Currently, cell transplantation has gained increasing attention as a scientifically valid method for dentin-pulp complex regeneration. This multidisciplinary approach which involves the interplay of three key elements of tissue engineering—stem cells, scaffolds, and signaling molecules—has produced an impressive number of favorable outcomes in preclinical animal studies. Nevertheless, many practical hurdles need to be overcome prior to its application in clinical settings. Apart from the potential health risks of immunological rejection and pathogenic transmission, the lack of a well-established banking system for the isolation and storage o...
Objectives: To describe the associations among spouses and their children regarding their oral he... more Objectives: To describe the associations among spouses and their children regarding their oral health knowledge, attitude and behaviours. Methods: The study population was households with a child attending grade 1 in primary school in Hong Kong. Selected schools in different districts participated. Visits to the students' homes were made. The father and the mother each separately completed a questionnaire on his/her own oral health knowledge, attitude and behaviours. Another questionnaire about the child's oral health behaviour and parents' attitude towards their child's oral health was completed by parents. Spearman's correlation and McNemar's test were used to assess the relationship between father's, mother's, and their child's oral health knowledge, attitude, behaviours. Result: So far, 143 families including 117 fathers, 140 mothers and 143 children participated. Twice daily was the most common frequency for tooth brushing (69%) reported by t...
Objective: To compare the appearance of dentin after application of silver diammine fluoride (SDF... more Objective: To compare the appearance of dentin after application of silver diammine fluoride (SDF) solution to that of dentin after application of SDF solution followed by potassium iodide (KI) solution. Method: Rectangular dentin blocks from root trunks of extracted permanent molars were cut into four blocks each. All blocks were coated with clear varnish except one flat surface of similar size. The 4 dentin blocks from the same tooth were allocated into four different groups randomly. Gp1- Artificial caries lesions (≈200µm deep) created (BHI broth, multi-species cariogenic bacteria, 10 days) + SDF; Gp2-Artificial caries lesion created + SDF + KI; Gp3- immersed in sterilized BHI broth (10 days) + SDF; Gp4- immersed in sterilized BHI broth (10 days) + SDF + KI. Color of the dentin blocks was recorded using PANTONE color sheets and was coded into 1-Light yellow (PANTONE code: 12-0704-TPX/11-0907-TPX); 2-Yellow (1205U/7401U); 3-Light brown/Greyish (4635U/402U); 4-Dark brown/Black (462...
Objective: OHIDL was developed to measure the perceived oral health impacts on daily life. The tr... more Objective: OHIDL was developed to measure the perceived oral health impacts on daily life. The transition scale in OHIDL was used to measure the change in perceived impacts after dental treatment. This study aimed to examine its longitudinal validity. Method: Elderly subjects aged 55 years or above were recruited from four dental clinics in Hong Kong. They were asked to rate the intensity level of 16 items in OHIDL before and after dental treatment. They were also asked to retrospectively rate the transition (change of the intensity) of these items after the treatment. Intensity and transition scores were calculated through summing up the responses. Change score was calculated as the difference between the two intensity scores before and after treatment. The associations of the transition and change scores with the global rating of change were used to evaluate their responsiveness. Result: A total of 176 subjects (mean age: 60.1 years; SD: 8.1) completed the follow-up interviews aft...
Objectives: to describe the influence of oral hygiene and denture wearing on root surface caries ... more Objectives: to describe the influence of oral hygiene and denture wearing on root surface caries in community-dwelling elders in Hong Kong Method: The study population was community-dwelling elders aged over 55 years who had at least 5 teeth with exposed root surfaces and self-care ability for normal daily activities. Ethical approval from IRB was obtained. Subjects were recruited from 12 elderly social centres and they were examined there by one trained examiner using disposable dental mirrors attached to an intra-oral LED light and CPI probes. Status of the expose root surfaces, presence of plaque, and denture status were recorded. A Visible Plaque Index (VPI) score was calculated by dividing the percentage of surfaces with plaque visible to naked eyes by the total number of root surfaces examined. Results: A total of 271 elders and 10866 exposed root surfaces were included in this study. Their mean age was 72.3 years (SD=6.2) and 77% were women. Elders with higher VPI scores had ...
Objective: To explore traditional oral health beliefs and oral health practice among Bulang peopl... more Objective: To explore traditional oral health beliefs and oral health practice among Bulang people, an ethnic minority group who lives in remote villages in Southwest China which is known to have black teeth. Methods: This qualitative study was conducted with ethics approval in 2013 in Yunnan, China where most Bulang people live. The study used a community based participatory method to collect the needed information. Village leaders, chiefs, elders and senior people were invited for a focus group discussion. Questions on traditional oral health beliefs, oral hygiene practice, and traditional therapeutic methods for tackling dental problems were asked. The discussions were video-recorded, transcripts made, and data were extracted. The focus group discussions were repeated in different villages until there was data saturation, i.e. no new information was found. Results: Three focus group discussions with 18 Bulang participants were conducted. They believed their dentition was good if ...
Fluoride varnish was incorporated into clinical dentistry to reduce caries; its use in the U.S. h... more Fluoride varnish was incorporated into clinical dentistry to reduce caries; its use in the U.S. has increased progressively since it was approved by the FDA in 1994. This paper reviewed clinical studies and found that fluoride varnish's effectiveness in caries prevention, ease of application, and safety give it an advantage over other types of topical fluoride treatments (such as gels and rinses) or other caries management methods. As a result, it is regarded as one of the superior topical fluoride agents for young children.
The aim of the present study was to test the presumptive therapeutic effect of chlorhexidine digl... more The aim of the present study was to test the presumptive therapeutic effect of chlorhexidine digluconate in a population with untreated gingivitis and presence of abundant calculus. SETTING AND STUDY DESIGN: Sixty subjects (approximately mean age of 23.4) were recruited from a knitting factory in the Province of Guangdong, People&amp;amp;#39;s Republic of China. By applying a double-blind clinical trial design the participants were divided into two groups (Test and Control) and matched according to their mean GI scores. The Test group (n = 20) was assigned to two daily mouthrinses for 6 days per week using 0.12% chlorhexidine digluconate (Peridex). The Control group (n = 40) rinsed twice daily with a placebo solution. All the rinsings were supervised and timed for 45 s. No attempt was made to influence the oral hygiene habits of the participants. Prior to and after 3 months of the supervised rinsing, plaque was scored using the Plaque Index system (PII), and gingivitis was assessed using the criteria of the Gingival Index system (GI). Calculus was scored according to the Calculus Surface Severity Index system (CSSI), and stain was also graded by the Discoloration Index system (DI). After 3 months, the Test group (n = 13) showed significant reduction in mean PII, GI and percentage of gingival bleeding (GB%), while significant increases in mean DI were observed. The improvement in gingival health was observed at all regions with marked reduction in mean GI (from GI = 1.40 to 1.08) and GB% reduction by 24-52%. The proportion of GI = 2 was also reduced significantly from 50-36%. The Control group (n = 23) also showed a decrease in mean PII but significant increases in the mean GI and GB%. Intergroup comparison showed statistically significant differences between mean GI, percentage of gingival bleeding (GB%) and mean DI for the test and control groups after 3 months of supervised rinsing. However, there were no significant intergroup differences for mean PII. In conclusion, there was a significant effect of chlorhexidine on gingivitis, although the effect may be too limited to assure prognostic benefits in the prevention of future disease progression.
Long-term aim is to determine optimum interventions to reduce dental caries in children in disadv... more Long-term aim is to determine optimum interventions to reduce dental caries in children in disadvantaged communities and minimise the effects of exclusion from health care systems, of ethnic diversity, and health inequalities. Generation of initial explanatory models, study protocol and development of two standardised measures. First, to investigate how parental attitudes may impact on their children's oral health-related behaviours and second, to assess how dentists' attitudes may impact on the provision of dental care. Core research team, lead methodologists, 44 consortium members from 18 countries. To complete the development of the questionnaire, the initial set of items was administered to parents (n = 23) with children in nursery schools in Dundee, Scotland and sent to the same parents one week later. A standardised measure examining barriers to providing dental care for children aged 3 to 6 years was developed. 20 dentists working in primary dental care in Scotland co...
The objective of this study was to review orofacial functional impairments among patients followi... more The objective of this study was to review orofacial functional impairments among patients following stroke, including objective and subjective assessment. A structured search strategy was applied to three electronic databases (Pubmed, Embase, and Web of Science) to identify effective papers. Relevant data regarding subjects, method, outcomes, and key findings were extracted from the effective papers and the results were summarized. The initial search yielded 5227 papers, and 18 effective papers (Kappa: 0.971) were in accordance with the inclusion criteria. The patients with stroke consistently showed a decreased lip force, salivary flow rate, and chewing performance compared with the healthy controls. Due to equivocal results gained from the effective papers, the qualitative assessments regarding whether there was any change in masticatory force on the affected side and oral health-related quality of life were inconclusive. Existing evidence highlights a number of compromised orofac...
the baseline parameters were increasing indicating increasing hazard rates from interval 1 to 6. ... more the baseline parameters were increasing indicating increasing hazard rates from interval 1 to 6. Results based on the logistic regression models were similar. In conclusion, the use of the MCMC approach and non-informative prior in a Bayesian framework to mimic the ML estimation in a frequentist approach in multilevel modelling of clustered grouped survival data can be easily applied with the use of the software WinBUGS.
To evaluate the preventive effect of Er:YAG laser (EYL) irradiation followed by silver diamine fl... more To evaluate the preventive effect of Er:YAG laser (EYL) irradiation followed by silver diamine fluoride (SDF) application on dentine with cariogenic biofilm challenge. Twenty-four dentine slices were prepared from extracted sound human third molars. Each slice was cut into four parts for SDF application, followed by EYL irradiation (group SL), SDF application (group S), EYL irradiation (group L) and water (group W). The specimens were subjected to cariogenic biofilm challenge for 12 h, followed by immersion in a buffered remineralising solution containing calcium chloride and sodium hypophosphate for 12 h at 37 °C. Surface morphological changes in the specimens were examined using scanning electronic microscopy. Elemental analysis was performed using energy-dispersive X-ray spectrometry. Micro-mechanical properties were investigated by nanoindentation. The specimen surfaces of groups SL and L showed laser melting contours with narrowed dentinal orifices. Group S showed a partial tubular occlusion. A porous surface was observed in group W, indicating demineralisation. The mean (SD) fluoride weight percentages were 3.93 (0.91), 3.10 (0.61), 0.17 (0.09) and 0.32 (0.07) in groups SL, S, L and W, respectively, (p<0.001; SL, S>L, W). The mean (SD) micro-hardness values in GPa were 1.84 (0.22), 0.49 (0.13), 0.41 (0.11) and 0.30 (0.06) in groups SL, S, L and W, respectively, (p<0.001; SL>S>L, W). The mean (SD) elastic moduli in GPa were 75.1 (7.2), 20.0 (1.3), 24.3 (5.2) and 20.2 (2.8) in groups SL, S, L and W, respectively, (p<0.001; SL>S, L, W). SDF application followed by EYL irradiation on a dentine surface increased its resistance to cariogenic biofilm challenge.
To investigate the inhibitory effects of 38% silver diamine fluoride (SDF) on demineralised denti... more To investigate the inhibitory effects of 38% silver diamine fluoride (SDF) on demineralised dentine. Human dentine blocks were demineralised and allocated to four groups: SF, F, S and W. The blocks in group SF received a topical application of 38% SDF solution (253,900ppm Ag, 44,800ppm F), group F received a 10% sodium fluoride solution (44,800ppm F), group S received a 42% silver nitrate solution (253,900ppm Ag) and group W received deionised water (control). They were subjected to pH cycling using demineralisation solution (pH 5) and remineralisation solution (pH 7) for 8 days. The surface morphology, crystal characteristics, lesion depth and collagen matrix degradation of the specimens were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-CT testing and spectrophotometry with a hydroxyproline assay. The surface morphology under SEM showed evident demineralisation with exposed collagen in groups S and W, but not in group SF. Clusters of granular spherical grains were observed in the cross-sections of specimens in groups SF and F. XRD revealed precipitates of silver chloride in groups SF and S. The mean lesion depths (±SD) of groups SF, F, S and W were 182 ± 32μm, 204 ± 26μm, 259 ± 42μm and 265 ± 40μm, respectively (SDF, F&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;S, W; p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). Groups SF and S had significantly less hydroxyproline liberated from the dentine matrix than groups F and W (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). The use of 38% SDF inhibited demineralisation and preserved collagen from degradation in demineralised dentine. SDF application positively influences dentine remineralization.
A particle swarm optimization (PSO) based algorithm for finding the Pareto solutions of multiobje... more A particle swarm optimization (PSO) based algorithm for finding the Pareto solutions of multiobjective design problems is proposed. To enhance the global searching ability of the available PSOs, a novel formula for updating the particles' velocity and position, as well as the introduction of craziness, are reported. To handle a multiobjective design problem using the improved PSO, a new fitness assignment mechanism is proposed. Moreover, two repositories, together with the age variables for their members, are introduced for storing and selecting the previous best positions of the particle as well as that of its companions. Besides, the use of age variables to enhance the diversity of the solutions is also described. The proposed method is tested on two numerical examples with promising results.
Uploads
Papers by Edward Lo