Recent Research Experience in Preventive Dentistry and Oral ...
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Recent Research Experience Recent Research Experience in Preventive Dentistry and Oral Epidemiologyin Preventive Dentistry and Oral Epidemiology
Gao Xiaoli11 Feb 2008
Outline:Outline:
Ph.D. Research (2004-2007)
Other Research Involvements (2000-2007) Msc research Educational research Co-supervising Undergraduate Research Opportunities Programme (UROP) projects
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Caries Status among Preschoolers in Singapore Caries Status among Preschoolers in Singapore and Development/Validation of and Development/Validation of
Caries Risk Assessment/Prediction ModelsCaries Risk Assessment/Prediction Models
Gao Xiaoli
Department of Preventive Dentistry
Faculty of Dentistry
National University of Singapore
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Caries Decline in Children and Young AdultsCaries Decline in Children and Young Adults
in Developed Countriesin Developed CountriesI I NNTTRROODDUUCCT T I I OONN
(WHO, 2003)
Caries Remains to Be a Caries Remains to Be a Ubiquitous Disease Threatening Oral Health
4
Age group
Survey year
% affected
dmft Reference
Norway
5 yrs 1985
1997
2000
50.1
30.4
38.9
1.1
1.5
Haugejorden &
Birkeland, 2002
I I NNTTRROODDUUCCT T I I OONN
Caries Resurgence among Young ChildrenCaries Resurgence among Young Children
All increases in prevalence rate and/or dmft/dmfs are statistically significant (p<0.05).
Caries trend in Norway for 5-year-olds (Haugejorden & Birkeland, 2002)
50.1%30.4%
38.9%
5
Caries Resurgence among Young ChildrenCaries Resurgence among Young ChildrenCountry Age group Survey year % affected dmft Reference
Netherland
Friesland 6 yrs 1982 3.8 Frencken et al., 1990
1988 4.6
Hague 6 yrs 1984 1.6 Truin et al., 1993
1989 3.1
UK 5 yrs 1999-2000 2.55 Pitts et al., 2003
2001-2002 2.76
Australia 6 yrs 1998
2002
1.51 Armfield & Spencer,
20031.67
Canada 5 yrs 1988 1.10 Speechley & Johnston,
19961992 1.16
7 yrs 1988 1.76
1992 1.91
9 yrs 1988 1.70
1992 1.76
USA 2-5 yrs 1988-1994 24.2 1.10 US/DHHS,
1999-2004 27.9 1.17 2007
I I NNTTRROODDUUCCT T I I OONN
All increases in prevalence rate and/or dmft are statistically significant (p<0.05).
6
Polarized Distribution of Caries
Minority of high-risk children are carrying the majority of caries lesions.
Western industrialized countries: 25% of the children and adolescents account for 80% of all affected surfaces (Seppa, 2001).
Singapore: 25% of preschool children with high caries rate (deft>2) were carrying 74% of lesions (Hsu et
al., 2001).
I I NNTTRROODDUUCCT T I I OONN
7
Polarized distribution of cariesPolarized distribution of caries
Importance of Caries Risk AssessmentImportance of Caries Risk AssessmentI I NNTTRROODDUUCCT T I I OONN
Risk-based individualized
treatment planning
Quality dental careCost-effective caries control
(NIH Consensus Panel, 2001; Featherstone et al, 2003)
Risk-basedtargeted
prevention/intervention
Community Community settingsetting
Clinical Clinical settingsetting
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Status of Caries Risk Assessment (CRA) Status of Caries Risk Assessment (CRA) Research and PracticeResearch and Practice
No CRA model with sufficient accuracy is available.
I I NNTTRROODDUUCCT T I I OONN
Limited practice of CRA
At the population level (Nishi et al., 2002)
In the educational setting (Brown, 2007)
In the clinical setting (NIH Consensus Panel, 2001)
CRA models with sufficient sensitivity, specificity & simplicity need to be explored and validated (NIH Consensus Panel, 2001).
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Singapore Population Singapore Population
Tropical Island country in Southeast Asia
Population size: 4,351,400
Multiracial population:
Chinese (77%) Malays (14%)
Indians (8%) Others (1%)
I I NNTTRROODDUUCCT T I I OONN
(Loh, 1996; Singapore Department of Statistics, 2006)
Caries Control Approaches in SingaporeCaries Control Approaches in Singapore
Water fluoridation (1958-)
Covering 100% of the population
Fluoride level: 0.7 ppm (1958-1992), 0.6 ppm (1992-)
School dental service (1961-)
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Caries Prevalence among Singapore Caries Prevalence among Singapore SchoolchildrenSchoolchildren
Monitored at regular basis through national surveys
from 1957-1994
Continuous decline of caries prevalence
I I NNTTRROODDUUCCT T I I OONN
Year dft
(6-11 year-olds)
DMFT
(6-18-year-olds)
% affected
(permanent dentition)
(6-18 years)
1970 2.60 2.95 70
1994 1.08 1.05 41
(Lo & Bagramian, 1997)
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Caries Prevalence among Singapore Caries Prevalence among Singapore Preschoolers Preschoolers
I I NNTTRROODDUUCCT T I I OONN
Population-based study is needed.
Epidemiological data are scarce.
Only limited data from small, convenience samples
are available.
N Age
(year)
Sample %
affected
dft
Hsu et al., 2001 67 3-5 Convenience sample
One kindergarten
54
Hong, 2003 236 2-4 Convenience sample
3 Government dental clinics
48 2.2
Pine et al., 2004 117 4 Convenience sample 1.48
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Main Objectives
The main objectives of this population-based, prospective study are:
OOBBJJEECCT T I I VVEESS
1. To profile the caries status among preschoolers in
Singapore.
2. To develop and validate practical biopsychosocial CRA program, for caries control and cost control, at the individual and community levels.
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1) To characterize the caries prevalence, incidence and disease pattern.
2) To reveal the oral health knowledge, attitude and practice.
3) To profile the caries-related biological characteristics (salivary, microbiological, and plaque acidity).
4) To identify the caries risk factors/indicators.
5) To develop and validate biopsychosocial CRA models.
Specific AimsOOBBJJEECCT T I I VVEESS
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MMEETTHHOODDSS
SamplingSampling
Sampling methodSampling method
Stratified cluster random sampling
Sampling frameSampling frame People’s Action Party Community Foundation
(PCF) Education System, the main provider of preschool education in Singapore.
Covered 80% of the population.
Sampling unitSampling unit
A PCF kindergartenA PCF kindergarten
15
13 PCF kindergartens
1782 children
889 males, 892 females
Aged 3-5 years
Response rate: 86%
With parents/guardians’ informed consents National University of Singapore Institutional Review
Ethical Approval 04-155
•
MMEETTHHOODDSS
SubjectsSubjects
Geographic distribution of participating kindergartens
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Demographic
Background
Socio-economic Status
Oral Health Behaviors Others
Age
Gender
Race
Country of birth
Nationality
Mother’s education
Father’s education
Housing type
Primary caregivers
Infant feeding history
Diet habits
Oral hygiene practice
Topical & systemic fluoride applications
Utilization of dental care services
Systemic disease and medication
Parental knowledge/attitudes on oral health
Parent-administered, structured questionnaireParent-administered, structured questionnaire
MMEETTHHOODDSS
Data Collection Data Collection
Pre-tested among 12 parents of different races and educational backgrounds.
Totally 1754 (98.4%) questionnaires were completed.
Completed by parents (97%) or other guardians (3%)
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Oral Examinations Method / Index
Caries status examination WHO criteria and procedures (WHO, 1997)
Oral hygiene evaluation Silness-Löe Plaque Index
Oral examinationsOral examinations
MMEETTHHOODDSS
Data Collection Data Collection
Portable dental chair with a fiber-optic light
Visual and tactile inspection
No radiographs were taken
One examiner Duplicate examinations on 1/10 randomly selected subjects for assessing the intra-examiner reliability
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Tests Materials & Method
Salivary Tests Salivary flow rate Stimulated whole saliva
Saliva buffering capacity Dentobuff® test kit
Microbiological Tests Level of mutans Streptococci (MS) Dentocult® SM Strip mutans
Level of Lactobacilli (LB) Dentocult® LB test kit
Plaque pH Test Plaque pH Micro-touch method with a microelectrode set Beetrode®
Biological testsBiological tests
MMEETTHHOODDSS
Data Collection Data Collection
19
Follow-up of Follow-up of caries statuscaries status
After 12 months
1576 (88%) children were traced
Same procedures and criteria
MMEETTHHOODDSS
Data Collection Data Collection
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Kappa coefficient
Chi-square tests
Tukey pos-hoc tests or independent t-tests Kruskal-Wallis tests or Mann-Whitney tests
Multiple logistic, ordinal, and linear regressions Identifying caries risk factors Construction of CRA models
Receiver Operation Characteristics (ROC) analysis Identifying optimal cut-off points Evaluating the model performance
MMEETTHHOODDSS
Statistical AnalysisStatistical Analysis
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50% for
model construction
50% for
model validation
Subjects
“Splitting data” design
External Validity
Model Construction and ValidationModel Construction and ValidationMMEETTHHOODDSS
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Results
1. Intra-examiner reliability and profile of study sample
2. Caries prevalence, incidence and disease pattern
3. Oral health knowledge, attitude and practice
4. Caries-related biological characteristics5. Caries risk factors/indicators6. CRA models
RREESSUULLTTSS
23
Intra-Examiner ReliabilityIntra-Examiner Reliability
Examination Level Outcome Kappa
Baseline Follow-up
Caries Surface Sound
Decayed
Extracted
Filled
0.958 0.961
Tooth Sound
Affected by caries
0.979 0.977
Dentition Sound (deft=0)
Affected by caries (deft>0)
0.987 0.986
Oral hygiene Surface Plaque Score 0
Plaque Score 1
Plaque Score 2
Plaque Score 3
0.913
-
RREESSUULLTTSS
24
(1)Sample
Population
N %
(2)Residential Population
in Singapore*%
Difference Between
(1) and (2)
P
Total 1782
Race Chinese 1208 67.8 76.8 <0.001
Malay 341 19.1 13.9
Indian 165 9.3 7.9
Others 68 3.8 1.4
Gender Male 889 49.9 49.9 0.992
Female 893 50.1 50.1
Housing HDB# 1-3 rooms 329 18.9 19.1 0.816
HDB# 4-5 rooms 1050 65.9 65.7
Private housing 265 15.2 15.2
* Population statistics from Singapore Population survey (Singapore Department of Statistics, 2005).
# HDB stands for Housing & Development Board, the main authority managing the development of public housing in Singapore.
Characteristics of Sample PopulationRREESSUULLTTSS
25
Reweighing for “Race” for Main Caries Statistics
% affected
(a)
% in the whole Singapore population
(b)
Re-weighed
(a) x (b)/100
Chinese 39.5 76.8 30.3
Malay 43.4 13.9 6.0
Indian 37.1 7.9 2.9
Others 48.3 1.4 0.7
Total 40.3 (Crude)
40.0 (Adjusted)
Example
RREESSUULLTTSS
26
Results
1. Intra-examiner reliability and profile of study sample
2. Caries prevalence, incidence and disease pattern
3. Oral health knowledge, attitude and practice
4. Caries-related biological characteristics5. Caries risk factors/indicators6. CRA models
RREESSUULLTTSS
27
Caries Prevalence %
Affected
(deft>0)
% with
Untreated
Teeth (d- >0)
%
Rampant
Caries a
Mean (SD) Components of
Affected Teeth
deft defs d- e- f-
Crude 40.3 38.8 17.1 1.57
(2.79)
3.38
(7.63)
1.41 (2.61)
0.04
(0.35)
0.12 (0.66)
Adjusted b 40.0 38.5 16.5 1.54
(2.75)
3.30
(7.49)
1.38
(2.56)
0.04
(0.35)
0.13
(0.66) % affected rate: 40%
3 year-olds: 26% 4 year-olds: 37% 5 year-olds: 49%
Mean (SD) deft & defs: 1.54 (2.75) & 3.30 (7.49)
% with rampant caries (defined as caries affecting the smooth surfaces
of two or more maxillary incisors): 16.5%
Severe Early Childhood Caries (S-ECC) (AAPD criteria): 28%
d- component: 90%
a Rampant caries defined as caries affecting the smooth surfaces of two or more maxillary incisors (Al-Malik et al., 2002).
b Main statistics adjusted by “race”.
RREESSUULLTTSS
28a Rampant caries was defined as caries affecting the smooth surfaces of two or more maxillary incisors (Al-Malik et al., 2002). b HDB stands for Housing & Development Board, which is the main authority managing the development of public housing in Singapore.
* There were significant differences (p<0.05) in the proportions/means between groups with different number of *s.
Disparity of Oral Health RREESSUULLTTSS
29
Significant Caries Index (SiC), i. e. the mean (SD) deft for one third of the population with the highest deft values (Bratthall, 2000):
4.49 (3.23)
Polarized Distribution of Caries
% of children % of lesions
deft>2 23% 88%
deft≥4 16% 78%
RREESSUULLTTSS
30
44% of children developed new caries, including 13.3% of children who were caries-free at baseline.
Mean (SD) increase of affected teeth and surfaces
0.93 (1.42) and 1.76 (3.18)
1-Year Caries Incidence1-Year Caries IncidenceRREESSUULLTTSS
31
Most Affected SurfacesMost Affected Surfaces
Surfaces affected per thousand surfaces at risk
2nd upper molar occlusal 102.2
2nd lower molar occlusal 100.4
1st lower molar occlusal 76.1
2nd upper molar lingual 56.8
Upper central incisor mesial 45.4
RREESSUULLTTSS
32
Results
1. Intra-examiner reliability and profile of study sample
2. Caries prevalence, incidence and disease pattern
3. Oral health knowledge, attitude and practice
4. Caries-related biological characteristics5. Caries risk factors/indicators6. CRA models
RREESSUULLTTSS
33
Caregivers and Infant Feeding PracticeCaregivers and Infant Feeding PracticeCaregivers and infant feeding practice %
N=1754
Primary caregivers Parents 47
Grandparents 22
Maid
Grandparents and maid
17
11
Others 4
Breastfeeding ≤12 months 89
>12 months 11
Bedtime feeding with breast, bottle of
milk/ formula/juice, sweets at age of 1
Frequently/almost every night 37
Never/occasionally 63
Used milk bottle before sleep at age of 1 Frequently/almost every night 64
Never/occasionally 36
RREESSUULLTTSS
34
Diet HabitsDiet Habits
Diet habits
%
N=1754
Meals/snacks per day 3-5 times
≥6 times
87
13
Between-meal sweet snacks <2 times a day 55
≥2 times a day 45
Bedtime sweets without brushing teeth Frequently/almost every night 12
Never/occasionally 88
Do you agree “I have the ability to
withhold frequent sugar snacks from
my child between meals even when
he/she is crying for it”?
Agree
Neutral
Disagree
29
60
11
RREESSUULLTTSS
35
Oral Hygiene Practice Oral Hygiene Practice
%
Oral hygiene practice
N=1754
Frequency of toothbrushing <2 times a day 31
≥2 times a day 69
Time of brushing per time ≤2 minutes 70
>2 minutes 30
Adults’ guidance in toothbrushing Yes 45
No 55
Do you agree with the statement “I can do
a good job brushing my child’s teeth each
day thoroughly even when I am very busy”?
Agree Neutral Disagree
21
66
13
RREESSUULLTTSS
36
Oral Hygiene StatusOral Hygiene Status
Very goodPI<0.4
GoodPI 0.4-1.0
ModeratePI >1.0, ≤2.0
BadPI>2.0
% of Subjects(N=1782)
22.1 52.1 25.4 0.4
Demographic/socioeconomic subgroups with better oral hygiene:
Indians (p<0.001)
Girls (p=0.047)
Children of more educated fathers (p=0.025)
Oral hygiene behaviors linked to better oral hygiene:
Toothbrushing by adults or with adults’ guidance (p=0.014)Brushing more frequently (p=0.001) and longer per time (p=0.012)Parents’ confidence in brushing child’s teeth (p=0.002)Parents’ awareness of fluoride toothpastes (p=0.026)
RREESSUULLTTSS
37
Fluoride ApplicationsFluoride Applications
%
Fluoride applications
N=1754
Use of fluoride toothpaste Yes
No
Not sure
68
12
19
Ever lived in non-fluoridated communities Yes
No
Not sure
3
71
26
Use of other fluorides Yes
No
Not sure
5
78
17
RREESSUULLTTSS
38
Utilization of Dental ServicesUtilization of Dental ServicesUtilization of dental services %
N=1586
Age regarded as appropriate to
start dental check-ups
1-3 years
4-6 years
≥7 years
14
47
39
Annual dental visits for parents Yes 45
No 55
Annual dental visits for children Yes
No
8
92
Reason for not visiting dentists
No money
No time
Transportation difficulty
Dental fear
Teeth did not bother the child
Too young
Other reasons
12
9
1
15
58
8
1
RREESSUULLTTSS
39
Parental Knowledge/Attitude on Oral HealthParental Knowledge/Attitude on Oral Health %
Parental knowledge/attitude on oral health
N=1586
Did you ever receive advices about the
relationship between diet and tooth decay
from a dentist or medical doctor?
Yes
No
29
71
Have you ever been told about early
childhood caries (tooth decay)?
Yes
No
25
75
Do you think baby teeth are important?
Do you believe that putting baby to bed with
a milk bottle is bad for his/her teeth?
What do you think is the main reason for
tooth decay?
Yes
No
Yes
No
Tooth worms
Heatiness
Insufficient toothbrushing
Sugar
Bacteria
89
11
69
31
4
1
23
73
70
RREESSUULLTTSS
40
Systemic Diseases and Regular MedicationSystemic Diseases and Regular Medication
%
N=1586
Systemic diseases Yes
No
14
86
Regular medication Yes
No
5
95
Parents’ Perception of the Children’s Caries StatusParents’ Perception of the Children’s Caries Status
Sensitivity: 49%
Specificity: 87%
Accuracy: 72%
RREESSUULLTTSS
41
Discrepancy between knowledge/attitude and practice
Socio-economic characteristics
e.g. poor infant feeding practice
frequent sweets
poor oral health knowledge
barriers to dental services
Oral Health Knowledge Attitude and PracticeOral Health Knowledge Attitude and Practice
for low socio-economic group
RREESSUULLTTSS
42
Results
1. Intra-examiner reliability and profile of study sample
2. Caries prevalence, incidence and distribution
3. Oral health knowledge, attitude and practice
4. Caries-related biological characteristics5. Caries risk factors/indicators6. CRA models
RREESSUULLTTSS
43
MS level %
N=1782
Dentocult score 0: CFU/ml saliva<104 34
Dentocult score 1: CFU/ml saliva<105 13
Dentocult score 2: CFU/ml saliva 105 - 106 24
Dentocult score 3: CFU/ml saliva>106 29
High MS levels (CFU/ml saliva ≥105): 53% of children
Factors associated with MS infection (multiple regression)
Malay race (p=0.008) Female gender (p=0.001)
Low education of mother (p<0.001) Bedtime feeding (p<0.001)
Frequent sweets (p<0.001) Bedtime sweets (p<0.001)
Bad oral hygiene (p<0.001) LB level (p<0.001) Low plaque pH (p<0.001)
MS level is not associated with age, in the range of 3-5 years for this study sample.
Microbiological CharacteristicsMicrobiological CharacteristicsRREESSUULLTTSS
44
LB level %
N=1782
Dentocult score 0: CFU/ml saliva 103 71
Dentocult score 1: CFU/ml saliva 104 11
Dentocult score 2: CFU/ml saliva 105 7
Dentocult score 3: CFU/ml saliva 106 11
High LB level (>103 CFU/ml saliva): 29% of children
Factors associated with LB infection (multiple regression)
Age (p<0.001) Malay race (p=0.024) Low education of father (p<0.001)
Breastfeeding (p=0.001) Frequent sweets (p<0.001) Bedtime sweets (p=0.003)
Living in non-fluoridated communities (p<0.001) Bad oral hygiene (p<0.001)
Low buffering capacity (p=0.003) MS level (p<0.001) Low plaque pH (p<0.001)
Microbiological CharacteristicsMicrobiological CharacteristicsRREESSUULLTTSS
45
%
N=1782
Saliva flow rate Very low, <0.5 ml/min 74
Low, 0.5-0.9 ml/min 15
Reduced, >0.9, <1.1 ml/min 5
Normal, ≥1.1 ml/min 7
Saliva buffering capacity Adequate, saliva end-pH ≥6.0 80
Reduced, saliva end-pH 4.5-5.5 15
Low, saliva end-pH ≤4.0 5
Low saliva flow rate: 89% of subject, ?
especially young children (p=0.001), girls (p=0.039) and Malays (p=0.004).
Salivary CharacteristicsSalivary CharacteristicsRREESSUULLTTSS
Adequate saliva buffering capacity: 80% of children,
especially boys and older children (both p=0.001)
46
Plaque Acidity %
N=1782
High, Average pH <6.0 27
Moderate Average, pH 6.0-6.5 22
Low, Average pH >6.5 51
Factors associated with high plaque acidity (multiple regression)
Low education of father (p<0.001)
Bedtime sweets (p=0.002)
Not using fluoride toothpaste (p=0.033)
Bad oral hygiene (p=0.001)
LB level (p<0.001)
MS level (p<0.001)
Plaque pHPlaque pHRREESSUULLTTSS
47
Results
1. Intra-examiner reliability and profile of study sample
2. Caries prevalence, incidence and distribution
3. Oral health knowledge, attitude and practice
4. Caries-related biological characteristics5. Caries risk factors/indicators6. CRA models
RREESSUULLTTSS
48
N % with
caries
P b OR (95% CI)
of caries a
P b
Age (year) 3 191 27 <0.001 1 (referent) 0.001
4 823 40 2.00 (1.29-3.12)
5 562 53 3.25 (1.44-7.37)
(month) Continuous 1.06 (1.02-1.09) 0.001
Race Chinese 1078 45.3 <0.001 1 (referent) 0.010
Indian 141 27.0 0.45 (0.21-0.96)
Malay 296 56.4 1.84 (1.18-2.87)
Father’s Primary and below 236 60 <0.001 1 (referent) <0.001
education Secondary/polytechnic 1068 45 0.46 (0.23-0.90)
Bachelor and above 253 24 0.13 (0.06-0.32)
Caries Risk Factors/Indicators - Demographic & socio-economic
a Adjusted for all other factors
b P values from chi-square tests are used to compare rates whereas P values from multiple logistic regression
models are used to compare odds ratios.
RREESSUULLTTSS
49
N % with
caries
P b OR (95% CI)
of caries a
P b
Breastfeeding
(year) No breastfeeding
≤1 year
>1 year, ≤2 years
>2 years
301
1084
112
60
45
41
59
68
<0.001 1 (referent)
1.06 (0.75-1.49)
2.09 (1.14-3.41)
3.26 (1.60-6.63)
<0.001
(month) Continuous 1.03 (1.01-1.06) <0.001
Bedtime feeding at 1-year-old
Nothing/water/pacifier
Breast/milk/formula/
juice/sweet
980
577
40
51
<0.001 1 (referent)
1.52 (1.21-1.91)
<0.001
Bedtime sweets Never
Occasionally
Frequently
Almost every night
570
783
149
55
37
44
61
64
<0.001 1 (referent)
1.57 (0.77-3.19)
2.76 (1.45-5.23)
3.61 (1.88-6.95)
<0.001
Caries Risk Factors/Indicators - Infant feeding history & diet habits
a Adjusted for all other factors
b P values from chi-square tests are used to compare rates whereas P values from multiple logistic regression models
are used to compare odds ratios.
RREESSUULLTTSS
50
N % with
caries
P b OR (95% CI)
of caries a
P b
Toothbrushing frequency None Once Twice 3 times > 3 times
18469980
758
834343490
0.001 1 (referent)0.15 (0.04-0.53)0.15 (0.04-0.53)0.19 (0.05-0.73)
0 (0.00-0.00)
0.030
Toothbrushing without adult’s guidance
NoYes
795953
2228
0.011 1 (referent)1.49 (1.05-2.05)
0.014
Uses of fluoride toothpaste
Yes/not sure
No
1356
201
44
44
0.879 1 (referent)
1.64 (1.03-2.61)
0.038
Uses of other fluorides Yes/not sure
No
337 1195
47
42
0.197 1 (referent)
1.84 (0.98-3.46)
0.060
Caries Risk Factors/Indicators
- Oral hygiene practice & fluoride application
a Adjusted for all other factors
b P values from chi-square tests are used to compare rates whereas P values from multiple logistic regression models are
used to compare odds ratios.
RREESSUULLTTSS
51
N % with
caries
P b OR (95% CI)
of caries a
P b
Think “tooth worms” is the main reasons of tooth decay
No
Yes
1651
65
23
15
0.176 1 (referent)
0.09 (0.01-0.45)
0.028
Age regarded appropriate for
dental check
≤3 yrs>3, <7 yrs7-8 yrs>8 yrs
190674497 50
44463954
0.080 1 (referent)2.31 (0.90-5.97)2.37 (0.89-6.27)
9.83 (1.87-51.71)
0.048
No annual visit because teeth
did not bother the child
NoYes
571
795
54
37
<0.001
1 (referent)
0.66 (0.47-0.92)
0.014
Do you think milk bottle is bad
for teeth?
YesNo
1185
532
39
42
1 (referent)
1.53 (1.07-2.18)
0.026
Caries Risk Factors/Indicators - Oral health knowledge and attitude
RREESSUULLTTSS
a Adjusted for all other factors
b P values from chi-square tests are used to compare rates whereas P values from multiple logistic regression models are
used to compare odds ratios.
52
CFU/ml
saliva
N % with
caries
P b OR (95% CI)
of caries a
P b
Level of LB <103 1029 30 <0.001 1 (referent) <0.001
104 148 69 1.98 (1.07-5.46)
105 99 81 2.27 (0.89-5.79)
>106 160 88 5.48 (2.44-12.23)
Level of MS <104 533 16 <0.001 1 (referent) <0.001
<105 198 28 2.31 (1.33-4.05)
105-106 382 53 6.55 (3.34-12.83)
>106 445 75 17.33 (9.31-32.26)
Caries Risk Factors/Indicators - Microbiological
a Adjusted for all other factors
b P values from chi-square tests are used to compare rates whereas P values from multiple logistic regression models are
used to compare odds ratios.
RREESSUULLTTSS
53
N % with
caries
P b OR (95% CI)
of caries a
P b
Plaque acidity Low, pH >6.5
Moderate, pH 6.0-6.5
High, pH <6.0
620
260
327
15
52
87
<0.001 1 (referent)
13.16 (8.03-21.08)
100.38 (63.78-151.39)
<0.001
<0.001
Continuous (plaque pH) 0.02 (0.01-0.03)
Plaque amount
<0.40.4-1.0>1.0, ≤2.0>2.0
357809402
8
11466763
<0.001 1 (referent)6.94 (3.45-10.68)
17.01 (9.23-34.67)7.27 (0.00-14659)
<0.001
Continuous 14.01 (7.58-22.33) <0.001
Caries Risk Factors/Indicators - Plaque
RREESSUULLTTSS
a Adjusted for all other factors
b P values from chi-square tests are used to compare rates whereas P values from multiple logistic regression models are
used to compare odds ratios.
54
N % with
caries
P b OR (95% CI)
of caries a
P b
Systemic disease NoYes
1503
251
44
44
1.000 1 (referent)0.51 (0.30-0.87)
0.014
Past caries Baseline deft=0
Baseline deft>0
940
636
22
76
<0.001 1 (referent)
3.15 (1.56-6.34)
0.001
Parents’ estimation of number of child’ decayed teeth
None
1-2 teeth
3-4 teeth
>4 teeth
1053
193
73
66
33
72
84
86
<0.001 1 (referent)
2.37 (1.02-8.69)
3.24 (0.86-10.48)
3.29 (0.83-11.32)
<0.001
Caries Risk Factors/Indicators - Others
RREESSUULLTTSS
a Adjusted for all other factors
b P values from chi-square tests are used to compare rates whereas P values from multiple logistic regression models are
used to compare odds ratios.
55
Results
1. Intra-examiner reliability and profile of study sample
2. Caries prevalence, incidence and distribution
3. Oral health knowledge, attitude and practice
4. Caries-related biological characteristics5. Caries risk factors/indicators6. CRA models
RREESSUULLTTSS
56
Sensitivity
(SN)
Specificity
(SP)
SN + SP
Plaque acidity Low, pH >6.5
Moderate, pH 6.0-6.5
High, pH <6.0
82.0
55.5
76.0
93.8
158
149
Past caries Baseline deft=0
Baseline deft>0 70.1 82.7 153
Level of MS <104
<105
105-106
>106
87.6
79.3
49.6
50.9
67.0
87.5
139
146
137
Level of LB <103
104
105
>106
50.9
34.8
22.1
89.4
95.1
97.5
140
130
120
Single Factors with Predictive ValuesRREESSUULLTTSS
57
Factor (X) β Sig
Age (mth) 0.041 0.009
Malay Race 0.719 0.003
Other fluorides 0.968 0.016
Regard “tooth worm” as reason for caries
-2.271 0.029
Do not think milk bottle is bad 0.692 0.022
Parents’ estimation of caries 2.552 <0.001
Constant (a) -8.655 <0.001
Community Screening CRA Model
Model performance:
Sensitivity (SN): 82.2% Specificity (SP): 81.2% SN+SP=163%
Positive predictive value: 56.4% Negative predictive value: 93.9%
False positive rate: 18.8% False negative rate: 17.8%
Accuracy: 81.4%
Area under ROC curve: 0.885Prob (Y=1) = exp (a + β1X1 + β2X2+…)/ [1+exp (a + β1X1 + β2X2+…)]
For identifying the 25% “high-risk” (deft>2) individuals.
Requires only a simple questionnaire.
RREESSUULLTTSS
58
Clinical Screening CRA ModelModel performance:
Sensitivity (SN): 85.5% Specificity (SP): 72.9% SN+SP=158%
Positive predictive value: 71.2% Negative predictive value: 86.4%
False positive rate: 27.1% False negative rate: 14.5%
Accuracy: 78.5% Area under ROC curve: 0.833
Prob (Y=1) = exp (a + β1X1 + β2X2+…)/ [1+exp (a + β1X1 + β2X2+…)]
RREESSUULLTTSS
For identifying the “any-risk” (∆deft>0) individuals.
Requires
Questionnaire
Oral hygiene evaluation
Factor (X) β Sig
Age (month) 0.081 0.000
Race 0.593 0.001
Father’s education -1.234 0.000
Sweet before sleep 0.584 0.000
Use of fluoride toothpaste 1.366 0.000
Toothbrushing frequency -2.068 0.015
Plaque amount 3.420 0.000
Constant (a) -4.296 0.039
59
Factor (X) β Sig
Age (mth) 0.058 0.018
Father’s education -0.502 0.003
Months of breastfeeding 0.064 0.008
Not using other fluoride 0.867 0.021
No annual visit because teeth did not bother the child
-0.744 0.018
Age regarded appropriate for dental check
0.263 0.008
Systemic diseases 0.982 0.016
Past caries experience 1.373 <0.001
Plaque index 2.186 <0.001
Level of LB 0.821 <0.001
Level of MS
Plaque pH
0.993
-4.642
<0.001
Constant (a) 19.696 <0.001
Full-Scale CRA ModelModel performance:
Sensitivity (SN): 90.4% Specificity (SP): 90.0% SN+SP=180%
Positive predictive value: 87.5% Negative predictive value: 92.4%
False positive rate: 10.0% False negative rate: 9.6%
Accuracy: 90.2% Area under ROC curve: 0.961
Prob (Y=1) = exp (a + β1X1 + β2X2+…)/ [1+exp (a + β1X1 + β2X2+…)]
For identifying the “any-risk” (∆deft>0) individual.
Requires
Questionnaire
Oral hygiene evaluation
Microbiological & plaque
pH tests
RREESSUULLTTSS
60
Comparison with Cariogram
% Area under
ROC curveSensitivity
(SN)
Specificity
(SP)
SN+SP Accuracy
Full-scale model 90 90 180 90 0.961
Clinical screening model 86 73 159 79 0.833
Cariogram 71 66 136 68 0.731
RREESSUULLTTSS
61
Caries has been successfully controlled among schoolchildren in Singapore.
However, the caries rate for preschoolers in Singapore is obviously higher than for most developed countries.
1Source of data: Lo and Bagramian, 1997 & this study 2Source of data: US/DHHS, 2007
Singapore1 USA2 P
Schoolchildren
Year of survey 1994 2002
6-11 years
% affected 41.8 49.0 <0.001
dft 1.08 1.67 <0.001
6-18 years
% affected 41.3 42.0 0.308
DFT 1.05 1.60 <0.001
Preschoolers
Year of survey 2005 2002
% affected 40.0 27.9 <0.001
dft 1.50 1.06 <0.001
Relatively Poor Oral Health among PreschoolersRelatively Poor Oral Health among PreschoolersD D I I SSCCUUS S S S IIOONN
62
Infant
Promoting proper feeding practice
Reducing colonization of cariogenic bacteria
Regular oral health education in kindergartens
Involve all caregivers
Meet the specific need of population subgroups
Extension of School Dental Service to preschoolersExtension of School Dental Service to preschoolers
Oral Health Education/Promotion Oral Health Education/Promotion D D I I SSCCUUS S S S IIOONN
63
Important of “Targeting”
The disparity of oral health is obvious in this population.
Some population subgroups, such as Malays and low socio-economic groups, should be targeted for caries prevention.
At individual level, those at-risk children need to be identified for early and intensified caries prevention and intervention.
D D I I SSCCUUS S S S IIOONN
64
Multiple risk factors/indicators identified in this study serve as important references for targeting high-risk groups and individuals.
Difference types of CRA Models were constructed and validated in this study. The combination of these models could provide options for different purposes at the community and clinical settings.
CRA ModelsCRA ModelsD D I I SSCCUUS S S S IIOONN
65
Methods
C4.5
Support Vector Machine (SVM)
NBay
Multi-Layer Perceptron (MLP)
ANN improved the accuracy of prediction
when limited information was available
for predicting “number of new affected surfaces” (p<0.05)
A computerized, user-friendly CRA program will be developed.
Data Mining with Artificial Intelligence Neural Network (ANN)
D D I I SSCCUUS S S S IIOONN
66
Early childhood caries is a health problem that warrants the attention of the profession and the resources of the society.
Sustainable oral health promotion programs should be established.
The CRA models established in this study could be practically useful tools for cost-effective caries control and individualized treatment planning.
ConclusionsConclusionsCCOONNCCLLU U S S IIOONNSS
67
ReferencesReferences Al-Malik MI, Holt RD, Bedi R (2002). Erosion, caries and rampant caries in preschool children in Jeddah, Saudi Arabia. Community Dental and Oral
Epidemiology 30:16-23. Armfield J, Spencer AJ (2003). Increase in caries experience in Australian Children. Abstract # 0151. The 81st General Session of the International
Association for Dental Research. June 25-28, 2003. Goteborg, Sweden. Bratthall D (2000). Introducing the Significant Caries Index together with a proposal for a new global oral health goal for 12-year-olds. Int Dent J
50(6):378-84. Brown JP. A new curriculum framework for clinical prevention and population health, with a review of clinical caries prevention teaching in U.S. and
Canadian dental schools. J Dent Educ. 2007 May;71(5):572-8. Ettinger RL (1999). Epidemiology of dental caries. A broad review. Dent Clin North Am 43(4):679-94. Featherstone JDB, Adair SM, Anderson MH, Berkowitz RJ, Bird WF, Crall JJ, et al (2003). Caries management by risk assessment: consensus
statement. J Calif Dent Assoc 31:257-69. Frencken JE, Kalsbeek H, Verrips GH (1990). Has the decline in dental caries been halted? Changes in caries prevalence amongst 6- and 12-year-old
children in Friesland, 1973-1988. Int Dent J 40:225-30. Haugejorden O, Birkeland JM (2002). Evidence for reversal of the caries decline among Norwegian children. Int J Paediatr Dent. 12(5):306-15. Holloway PJ (1991). International dental public health. Curr Opin Dent. 1(3):348-56. Hong HL (2003). Caries prevalence and associated risk factors in 2-4 year old children in Singapore. Thesis submitted for the degree of Master of
Science in Pediatric Denistry at the Horace H. Rackham School of Graduate Studies, the University of Michigan, U.S.A. (Thesis committee members: L Straffon, R Bagramian, C.Y. Hsu, H. Nainar).
Hsu CS, Lee WO, Teo CS (2001). Caries risk assessment of Singapore kindergarten children: A pilot study. Journal of Dental Research, 80 (2001): 566. (Special Issue on Dentistry). (Paper presented at 79th General Session & Exhibition of the International Association for Dental Research, 27-30 June 2001, Makuhari Messe & Prince Hotel, Chiba, Japan). (Abstract 316).
Lo GL, Bagramian RA (1997). Declining prevalence of dental caries in school children in Singapore. Oral Dis 3:121-5. Loh T (1996). Thirty-eight years of water fluoridation--the Singapore scenario. Community Dent Health 13:47-50. National Institute of Health (NIH) consensus panel (2001). National Institute of Health consensus development conference statement. Presented at the
Consensus Development Conference on Diagnosis and Management of Dental Caries Throughout Life, March 26-28, 2001. Natcher Conference Center, National Institutes of Health, Bethesda, MD. USA.
Nishi M, Stjernsward J, Carlsson P, Bratthall D (2002). Caries experience of some countries and areas expressed by the Significant Caries Index. Community Dent Oral Epidemiol 30(4):296-301.
Olsen CB, Brown DF, Wright FA (1986). Dental health promotion in a group of children at high risk to dental disease. Community Dent Oral Epidemiol 14(6):302-5.
Ong G, Yeo JF, Bhole S (1996). A survey of reasons for extraction of permanent teeth in Singapore. Community Dent Oral Epidemiol 24(2):124-7. Pine CM, Adair PM, Nicoll AD, Burnside G, Petersen PE, Beighton D, et al (2004a). International comparisons of health inequalities in childhood
dental caries. Community Dent Health 21(1 Suppl):121-30. Pitts NB, Boyles J, Nugent ZJ, Thomas N, Pine CM (2003). The dental caries experience of 5-year-old children in England and Wales. Surveys co-
ordinated by the British Association for the Study of Community Dentistry in 2001/2002. Community Dent Health 20(1):45-54. Seppa L (2001). The future of preventive programs in countries with different systems for dental care. Caries Res 35 (Suppl 1):26-9. Singapore Department of Statistics (2005): General household survey 2005. http://www.singstat.gov.sg/. Speechley M, Johnston DW (1996). Some evidence from Ontario, Canada, of a reversal in the dental caries decline. Caries Res 30(6):423-7. Truin GJ, van't Hof MA, Kalsbeek H, Frencken JE, Konig KG (1993). Secular trends of caries prevalence in 6- and 12-year-old Dutch children.
Community Dent Oral Epidemiol 21(5):249-52. U.S. Centers for Disease Control and Prevention (2005). Surveillance for dental caries, dental sealants, tooth retention, edentulism, and enamel fluorosis
- United States, 1988–1994 and 1999–2002. In: Surveillance Summaries, MMWR 54(No. SS-3). U.S. Department of Health and Human Services (US/DHHS) (2000). Oral health in America: a report of the Surgeon General. J Calif Dent Assoc,
28(9):685-95. U.S. Department of Health and Human Services (US/DHHS) (2007). Trend in oral health status: United States, 1988-1994 and 1999-2004. Centers for
Disease Control and Prevention, National Center for Health Statistics. Health, United States. World Health Organization (WHO) (1997). Oral health surveys: Basic methods. 4th edition. WHO Geneva. World Health Organization (WHO) (2001). Changing levels of dental caries experience (DMFT) among 12-year-olds in developed and developing
countries. http://www.whocollab.od.mah.se/index.html World Health Organization (WHO) (2003). The World Oral Health Report 2003. WHO, Geneva.
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Award
International Association for Dental Research
(IADR)
Lion Dental Research Award
New Orleans, USA, March 2007
69
Msc Research
Educational Research
Co-supervising Undergraduate Research Opportunities Programme (UROP) Projects
69
70
Msc Research
Synergistic Effect of Combined Laser-Fluoride Treatment on Root Demineralization
A low-energy CO2 laser treatment (energy density 1.14 J/cm2) has been established with effect on inhibiting root demineralization.
A synergistic effect of combined laser-fluoride treatment was demonstrated.
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
Groups N Mean (SD) of
Lesion Depth (µm)
Ranking * % Reduction
Control 15 160 (14) I
Laser alone 15 113 (8) II 30
Fluoride alone 15 111 (6) II 31
Fluoride + Laser 15 25 (7) III 85* The ranking order was obtained from the post hoc Tukey-Kramer multiple-comparison tests. Groups with different numerals are statistically different (p < 0.05).
Journal of Dental Research 85(10): 919-923
71
Msc Research
Synergistic Effect of Combined Laser-Fluoride Treatment on Root Demineralization
The possible mechanism may be the laser-induced fluoride uptake, in firmly and loosely bound forms.
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
Groups Mean (SD) of
Fluoride Uptake #
Ranking *
Firmly bound fluoride Non-laser 73 (24) I
Laser 368 (26) II
Loosely bound fluoride Non-laser 567 (33) III
Laser 777 (78) IV# The elemental analysis was carried out through Time of Flight - Secondary Ion Spectrometry (ToF-SIMS). There is no unit for fluoride concentration because the intensity of ionized 19F was normalized against the intensity of ionized 31P, the reference element for negative ions in the tooth.* The ranking order was obtained through a general linear model for repeated measurements. Groups with different numerals are statistically different (p < 0.05).
Journal of Dental Research 85(10): 919-923
72
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
Educational Research
Dentists’ knowledge attitudes and practice of preventive dentistry and oral health education in Singapore. Hsu CY, Loh T, Gao XL, Ong G. Submitted to Community Dental Health.
Dental students’ knowledge-attitude-practice of preventive dentistry. Hsu CS, Gao XL, Loh T, Ong G. Oral presentation at 16th South East Asia Association for Dental Education Annual Meeting, Sept 2005, Malacca, Malaysia. Abstract #SO-3.
Teaching reform and graduates’ knowledge attitude practice of preventive dentistry. Hsu CY, Loh T, Gao XL, Ong G. Oral presentation at 19th South East Asia Association for Dental Education Annual Meeting, Sept 2007, Bali, Indonesia. Abstract #SO-5.
Effects of multimodal and multi-dimensional learning in “Community Health Study” module. Hsu CY, Loh T, Gao XL. Poster presentation at 5th Asia Pacific Medical Education Conference, Jan 2008, University Cultural Center, National University of Singapore.
73
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
Educational Research
The teaching reform included
Review and reconstruction of curriculum
Adjustment of teaching philosophies and priorities Emphasizing interactive, collaborative, self-directed,
and reflective learning.
Employment of innovative teaching strategies Seminars, project-based modules, case studies, role-
plays, field trips, and student-centred community studies
Refinement of course requirement and assessment system Class activities, quizzes, taking home exams, group
projects, oral exams, and self/peer evaluation
74
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
Educational Research
The anonymous surveys among students showed
There were significant improvements in their satisfaction on the curriculum, interest in related subjects, attitude of learning, knowledge acquirement, and application of knowledge in their clinical practice and research projects.
This self-directed, truth-finding process has impacted their lives and re-directed their thinking.
Students were equipped with basic tools for their life-long learning and evidence-based dentistry.
75
Undergraduate Research Opportunities Programme (UROP) Project (1)
Preliminary Caries Risk Study in Chinese ChildrenPreliminary Caries Risk Study in Chinese Children
Oral health survey in a preschool education centre in Dali Bai Autonomous Region, Yunnan Province, P. R. China
N=235
Age range: 4-6 years
Caries is a severe oral health problem % affected: 87% Mean (SD) deft and defs: 5.6 (3.8) and 10.4 (7.7) d- component: 98.8%
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
76
Undergraduate Research Opportunities Programme (UROP) Project (1)
Preliminary Caries Risk Study in Chinese ChildrenPreliminary Caries Risk Study in Chinese Children
A few A few caries risk factorscaries risk factors have been identified sweet intakes (p=0.019) poor oral hygiene (p=0.004) not using fluoride toothpaste (p<0.001)
Cariogram did not predict the caries increment accurately in this population.
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
77
Acid-neutralizing Capability of Foods after Coca Cola Consumption
“Peanut and cheese” was an effective food therapy in neutralizing plaque pH drop induced by Coca Cola.
Consumption of “cheese alone” or “cheese and mushroom” possibly provides some protective effects.
The finding of this study is useful for providing diet advices for caries prevention dispensed to regular consumers of Coca Cola.
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
Undergraduate Research Opportunities Programme (UROP) Project (2)
78
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
Cariostatic Effect of Probiotic Drink YakultCariostatic Effect of Probiotic Drink Yakult®
A 2-week consumption of Yakult® reduced the acid production in plaque of moderate-risk young adults.
The mechanism may be the Yakult® effect on inhibiting cariogenic bacteria.
The probiotic drink Yakult® is promising in preventing caries.
Undergraduate Research Opportunities Programme (UROP) Project (3)
79
Awards for UROP Projects
2nd Place Award (2007)
Undergraduate Research Opportunities Programme Competition
National University of Singapore
Complimentary Award (2006)
Preventive Programme Competition
South East Asia Association for Dental Education (SEAADE)
OOTTHHEER R
I I NNVVOOLLVVEEMMEENNTT
8080
gaoxiaoli@nus.edgaoxiaoli@nus.edu.sgu.sg
81
Declaration
The studies reported in this presentation are the original works of the presenter and the research/ teaching team.
All intellectual properties related to these researches belong to National University of Singapore.
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