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

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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


All increases in prevalence rate and/or dmft are statistically significant (p<0.05).

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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).


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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.


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%)


(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


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


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

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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


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


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Follow-up of Follow-up of caries statuscaries status

After 12 months

1576 (88%) children were traced

Same procedures and criteria

MMEETTHHOODDSS


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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

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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

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(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

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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

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Results





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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

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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%

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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

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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

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Results





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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


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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


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

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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

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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

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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

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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

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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

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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%

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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

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Results


2. Caries prevalence, incidence and distribution



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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

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LB level %

N=1782

Dentocult score 0: CFU/ml saliva 103 71




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

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%

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)

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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

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Results





RREESSUULLTTSS

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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


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

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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


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




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




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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




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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




55

Results





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:




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

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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:




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.

http://www.singstat.gov.sg/



http://www.whocollab.od.mah.se/index.html

http://www.whocollab.od.mah.se/index.html

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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


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



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



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

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OOTTHHEER R



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.

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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


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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


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



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OOTTHHEER R


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.


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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


8080

[email protected]@nus.edu.sgu.sg

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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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