The Epidemiology of Dental Caries

1
The Epidemiology of Dental Caries
Department of Preventive Dentistry School
Hospital of Stomatology Wuhan
University Minquan Du ???
2
Types of study

• Descriptive studies cross-sectional,
  longitudinal, historical
• Analytical studies case-control, cohort
• Experimental study Clinical trials,
  Intervention, fields trials

3
?????? ??

• An Index is a graduated, numerical scale with
  upper and lower limits, with scores in the scale
  corresponding to specific criteria
• ???????????????????
• ????????
• ????????,??????????????????

4
An Ideal Index

• ?? Simplicity
• ?? Acceptability
• ?? Validity
• ?? Reliability
• ?? Sensitivity
• ??????? Quantifiability

5

• ????? reversible
• ???? gingivitis
• ????? cumulative
• DMF, dental caries

6
Scale for measurement

• Nominal scaleOrthodontic angles classification
• Marital status single, married, divorced,
  windowed
• Colour of hair red, yellow, black, green
• Types of Blood O, A, B , AB
• Ordinal scale plaque index Gingival Index, CPI
• Years of education 0, 1-5, 6-9, gt10
• Severity of disease mild, moderate,
  severity
• Interval temperature in Celsius temperature 22
  and 26, 32 and 36
• Ratio weight, mortality rate, DMFT

7
Examine equipment

• Artificial light
• Dental mirror
• CPI probe

8
A specially designed light weight CPI probe with
a 0.5-mm ball tip is used, with a black band
between 3.5 and 5.5 mm and between 8.5 and 11.5
mm from the ball tip
9
Oral Health Surveys 4th Edition

• Code
  Conditions
• Primary teeth Permanent teeth
• Crown Crown Root
• A 0 0
  Sound
• B 1 1
  Decayed
• C 2 2
  Filled, with decay
• D 3 3
  Filled, no decay
• E 4 -
  Missing

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12
????????

• ???????
• DMF?????????????????

D(decayed)M(missing)F(filled)T(teeth)
D(decayed)M(missing)F(filled) S(surface)
13
??????? dmft,dmfs?????????????????
deft,defs ?????????????????
dft,dfs ???????????????
14
deciduous caries
15
??????

• Mean DMFT?????????????????????
• ????????
• ??
• ????

Mean DMFS??????????????????????
????????? ???
????
16
? ?
17
???(caries prevalence rate)
?????????????????,?????????

• ?????

???
100
????
18
?????(caries incidence rate)
??????????,???????????

• ???????

?????
100
????
19

• 1995????????15???50?, ???????35?,??????D70,
  M2, F8,???????D210, M10, F16?
• ??????50?????,????10????????,???????15,????
  18,????????1995????????????????????????

20
???(caries-free rate)
??????????????????????

• ??????????

???
100
???????
21
??????? (proportion)

• ???????????????????????????
• ??????????
• ??????? 100
• ??????????????

22
????(Katz, root caries index)
????????,??????????????????????????

• ????

????
100
???????
23
????(Katz, root caries index)
An individual, or population

• Root surfaces decayed filled

RCI
100
Root surfaces with loss of periodontal
attachment Decayed Filled Sound
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25
??? 3544????????
?? ??  ?? ?? ????????? ?????(SD) ???????????(SD) RCI()
? 270 174 0.15 (0.55) 5.12 (6.41) 4.57 (15.74)
?? ? 270 172 0.19 (0.54) 4.35 (5.69) 8.29 (21.82)
? 540 346 0.17(0.55) 4.74 (6.07) 6.42 (19.07)

? 270 216 0.26(0.84) 6.97(6.62) 4.60(14.64)
?? ? 270 198 0.23(0.61) 4.64(5.49) 7.91(21.13)
? 540 414 0.24(0.74) 5.81(6.19) 6.18(18.09)

? 540 390 0.21(0.72) 6.05(6.58) 4.59(15.11)
?? ? 540 370 0.21(0.58) 4.50(5.59) 8.08(21.42)
? 1080 760 0.21(0.65) 5.27(6.15) 6.29(18.53)
26

• Root Caries Index according to teeth type
• in 3544 years old adults

27
???6574????????
?? ??  n ????????? ?????(SD) ???????????(SD) RCI()
? 270 258 0.71 (1.28) 11.79 (6.81) 8.38 (17.09)
?? ? 270 255 1.10 (1.62) 10.46 (6.43) 13.05(21.79)
? 540 513 0.90 (1.47) 11.13 (6.65) 10.70 (19.68)

? 270 250 1.00 (1.68) 10.75(6.74) 12.19 (20.47)
?? ? 270 248 1.19 (1.80) 9.71 (6.35) 14.30 (20.80)
? 540 498 1.10 (1.74) 10.23 (6.56) 13.24 (20.64)

? 540 508 0.86(1.50) 11.27 (6.79) 10.26 (18.90)
?? ? 540 503 1.14(1.71) 10.08 (6.40) 13.67 (21.29)
? 1080 1011 1.00 (1.62) 10.68 (6.62) 11.95 (20.19)
28

• Root Caries Index according to teeth type
• in 6574 years old adults

29
Community Dent Oral Epidemiol 2009 37
26026 Root caries patterns and risk factors of
middle-aged and elderly people in China Du MQ,
Jiang H, Tai BJ, Zhou Y, Wu B, Bian Z.
Abstract The objectives of this study were to
describe root caries patterns of Chinese adults
and to analyze the effect of selected demographic
and socioeconomic factors on these patterns. A
total sample of 1080 residents aged 3544-years-ol
d and 1080 residents aged 6574-years-old from
three urban and
30
???????????????The epidemic characteristics of
dental caries and its risk factors
31
WHO???????????(12?)

• ?? (DMFT) ??
• 0.01.1 ??
• 1.22.6 ?
• 2.74.4 ?
• 4.56.5 ?
• 6.6?? ??

32
Distribution of Region ????

• ???????????????,????????????
• ??????,????????????????,????????????
• ??????????????????????????????

33
????????????10???12?????

• ?? ???? ?? ??
  ???? ??
• ?? 1991 1.4
  ???? 1987 6.4
• ?? 1993 1.4
  ???? 1987 8.1
• ?? 1998 1.9
  ? ? 1990 7.0
• ?? 1992 2.6
  ? ? 1995 6.7
• ?? 1993 3.3
  ? ? 1986 6.7
• ??? 1995 2.2
  ???? 1988 6.3
• ??? 1993 2.3 ? ?
  ? 1989 6.0
• ??? 1989 1.9 ? ?
  ? 1983 5.9
• ???? 1993 1.1 ????
  1988 5.9
• ?? 1994 1.2
  ???? 1993 5.7

34
????
35
?????????(2005)
?? 5? 12? 3544? 6574? ??
?? ?? ?? ?? 3.7 68.4 0.6
32.5 2.1 63.8 3.6 75.0 ?? 3.2 63.0 0.5
25.3 1.9 60.7 3.7 75.6
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Distribution of Time ????

• ??11??12???????(??)
• 
  ??
  ??(1983) ??(1995)
• 
  
• ??? 1.41
  0.98
• ??? 1.17
  0.96
• ??? 1.41
  1.02
• ??? 0.36
  0.87
• ??? 0.69
  0.59
• ??? 0.46
  0.88
• ??? 0.76
  1.29
• ??? 1.22
  1.46
• ??? 0.90
  0.51
• ??? 0.91
  1.65
• ??? 0.57
  0.37
• ? ?
  0.67 0.88

38
Prevalence of deciduous caries in 5-year-old
children in Hubei province
year dmft
Prevalence () 1995 3.6
70.2 2005
2.5 55.5
39
Dental caries of permanent teeth
DMFT
Prevalence() 1995
2005 1995 2005 5
3.6 2.4
70.2 55.5 12 0.7
0.4 34.1 22.7
15 1.0 0.5
41.8 24.4 3544 1.4
1.2 53.0 47.0
6574 3.0 3.7
74.4 77.2
40
Comparison of Prevalence of Root caries in adults
41
Distribution of population ????

• Age ??
• Gender ??
• Urban and rural areas ??
• Race and Ethnicity ??

42
Age

• ????????????,?????????
• ?3??????????,?58??????????
• 6?????????,??????,???????
• 1215???????????,????????
• 25???????????
• ?????,??????,???????????

43
??11??544????????????(1995) ??
?? D M F
DMF
5? ?
0.54 0.00 0.00
0.54 ? 0.95
0.02 0.00 0.96
12? ? 37.74 0.36
6.00 40.60
? 47.37 0.47 8.22
51.02 15? ? 42.86
1.30 10.61 47.74
? 51.74 1.58
14.10 57.11 18? ?
44.25 2.52 15.01
50.52 ? 52.06
3.72 20.02 60.11 3544?
? 40.93 24.07 16.31
56.45 ?
54.43 28.98 25.04 69.56
44
Dental caries of permanent teeth
DMFT
Prevalence() 1995
2005 1995 2005 5
3.6 2.4
70.2 55.5 12 0.7
0.4 34.1 22.7
15 1.0 0.5
41.8 24.4 3544 1.4
1.2 53.0 47.0
6574 3.0 3.7
74.4 77.2
45
Gender

• ??????????,?????????
• ????????????
• ????????????
• ????????????????,??????????????????,????????
  ????????????????????????

46
???? (2005)

• ??? ?? ??
• ?? ??? ?? ???
• 5?? 3.5 66.3 3.5 65.7
• 12?? 0.5 25.3 0.6 32.5
• 3544?? 1.1 44.7 1.9 61.3
• 6574?? 2.9 68.6 3.6 75.0

47
???3544?????????? (2005)
?? ?? ???? D ?? SD F ?? SD DFT ?? SD ???()
?? ? 270 0.71 1.42 0.14 0.46 0.86 1.51 38.9
? 270 0.86 1.39 0.39 1.06 1.25 1.81 49.3
?? 540 0.79 1.41 0.26 0.83 1.05 1.67 44.1

?? ? 270 0.80 1.55 0.01 0.11 0.81 1.56 38.1
? 270 1.66 2.28 0.11 0.49 1.77 2.40 61.9
?? 540 1.23 2.00 0.06 0.36 1.29 2.08 50.0

?? ? 540 0.76 1.49 0.08 0.34 0.84 1.53 38.5
? 540 1.25 1.93 0.25 0.84 1.51 2.14 55.6
?? 1080 1.01 1.74 0.16 0.65 1.17 1.89 47.0
48
???6574??????????(2005)
?? ?? ???? D ?? SD F ?? SD DFT ?? SD ???()
?? ? 270 2.55 3.24 0.16 0.55 2.71 3.26 69.3
? 270 3.41 3.85 0.34 0.94 3.75 3.85 80.0
?? 540 2.98 3.58 0.25 0.78 3.23 3.60 74.6

?? ? 270 3.81 4.19 0.02 0.14 3.83 4.19 77.0
? 270 4.36 4.08 0.03 0.20 4.39 4.06 82.6
?? 540 4.08 4.14 0.03 0.17 4.11 4.13 79.8

?? ? 540 3.18 3.80 0.09 0.41 3.27 3.79 73.1
? 540 3.88 3.99 0.19 0.70 4.07 3.97 81.3
?? 1080 3.53 3.91 0.14 0.57 3.67 3.90 77.2
49
Urban and rural areas

• ??????,??????????????
• ?????????????(??????)?????????????,???????????????
  ?????

50
??11??544??????????(1995) ??(?)
??() ??() 5
0.65
0.94 12 48.32
40.82 15
55.70 45.89
18 58.22
49.53 3544
64.55 59.92
51

• ???????????????(2005)
• ??? ?? ??
• ?? ??? ?? ???
• 5?? 3.09 62.0 3.92 70.2
• 12?? 0.53 29.3 0.54 28.6
• 3544?? 1.87 61.4 1.96 60.7
• 6574?? 3.30 74.8 3.95 75.5
• 95????5????????????????

52
Race and Ethnicity

• ??????,?????????????,?????????????????
  ????

53
?????????

• The amount of fluoride intake
• The diet an nutrition
• The transmittion of cariogenic bactrias

54
Fluoride intake

• ???????????,??????????????
• ???????0.60.8ppm???

55
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56
??????????11?????????????????1995
57
Diet and nutrition

• ??????????????????????????,?????,?????
  ??
• ???????????????

58
????
59
????
60
Familial tendency

• ??????????,???????????????????????????????,???????
  ???????
• ?????????,??????????????????,????????????????

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Randomized controlled trial,RCT

• ????????????????,?????????,???????????????,???????
  ,???????????????????????????????
• ???????,?????,?????????,???????????????,??????????
  ???????

63
What is a clinical trial?

• ClinicalTrials.gov includes both
  interventional and observational types of
  studies.
• --Interventional studies are those in which the
  research subjects are assigned by the
  investigator to a treatment or other
  intervention, and their outcomes are measured.
• --Observational studies are those in which
  individuals are observed and their outcomes are
  measured by the investigators.

64

• Clinical trials provide the best scientific
  evidence for clinicians when they have to make
  clinical decisions (Evidence-based dentistry)
• We would like to produce the highest level of
  evidence to guide the best practice

65
What is a protocol?

• A protocol is a study plan on which all clinical
  trials are based. The plan is carefully designed
  to safeguard the health of the participants as
  well as answer specific research questions.
• A protocol describes what types of people may
  participate in the trial the schedule of tests,
  procedures, medications, and dosages and the
  length of the study. While in a clinical trial,
  participants following a protocol are seen
  regularly by the research staff to monitor their
  health and to determine the safety and
  effectiveness of their treatment.

66
Clinical study protocol

• ? A written protocol
• ? Controlled trials
• ? Randomisation
• ? Size of trial
• ? Double blind trials
• ? Definition of patients

67
Clinical study protocol

• ? Data management
• ? Statistical analysis
• ? Monitoring of trials
• ? Ethical consideration
• ? Adverse effect
• ? Staff, funding
• ? Publications

68
Randomized controlled trial

• ? Randomization Random numbers, throw a coin,
  dice.
• ? Control Study group, Positive control,
  Negative control
• ? Blind Single blind, Double blind, or placebo
• ? Replication

69
Randomization

• ?????(Simple randomization)??????????????????????
  ????????????????????????,?????????,??????????
• ?????(Block randomization)???????????????????????
  ????????????,????????????????,????????????????,???
  ??????????????????46????
• ?????(Stratified randomization)??????????????????
  ???,????????????,??????????????????????????,??????
  ????????????????

70
Randomisation

• The objective of randomisation is to ensure
  that there is no bias which will make the results
  invalid
• Randomized controlled trial (RCT)
• Random numbers, throw a coin, dice.

71
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72
Random numbers

• Table
  Random numbers
• --------------------------------------------------
  ----------------------------------------------
• Rows
  Columns
• 
  1-4 5-8 9-12
  1
  96
  22 74 70 80 46
  2
  82 14 73 36
  41 54 3
  21 47
  59 93 48 40
  4
  89 31 62 79 45 73
  5
  63 29 90 61
  86 39 6
  
  71 68 93 94 08 72
  7
  05 06 96 63
  58 24 8
  06 32
  57 11 81 59
  9
  91 15 38 54 73 30
  10
  54 60 28 35
  32 94
• --------------------------------------------------
  ------------------------------------------------

73
Control

• ????(??????)??????????????,?????????????????????,
  ??????????????????
• ????(concurrent control)??????????????,??????????
  ?????????,?????????????????,?????????????
• ????(self control)????????????????????,?????,????
  ?,???????????????????????????????????????,????????
  ????????
• ?????(placebo control) ????????,?????????????????
  ????????,?????????????????????????????????,???????
  ??,????????
• ????(blank control)?????????????????????????????
  ??,????????????????,????????????????????

74
Control

• Study group - subjects receiving the test
  intervention
• Control group - subjects as similar as possible
  to study group but not receiving test
  intervention
• Positive control, Negative control, Historical
  control, Self control

75
What is a control or control group?

• A control is the standard by which experimental
  observations are evaluated. In many clinical
  trials, one group of patients will be given an
  experimental drug or treatment, while the control
  group is given either a standard treatment for
  the illness or a placebo.

76
What is a placebo?

• A placebo is an inactive pill, liquid, or powder
  that has no treatment value. In clinical trials,
  experimental treatments are often compared with
  placebos to assess the experimental treatment's
  effectiveness. In some studies, the participants
  in the control group will receive a placebo
  instead of an active drug or experimental
  treatment.

77
Blind

• ?????????,?????,?????????????????????????????????
  ????????????????????????
• ?????????????????????????????????????????????,???
  ????
• ?????????????????????????????????????????????????
  ??????,????????????,?????

78
Blind

• Blind - examiners do not know which subjects are
  in the test or control group to avoid
  (unintentional) bias of examiner reporting
• Double blind - participants not knowing which
  group they belong to to avoid subjective bias in
  reporting of symptoms
• Dummy or placebo - similar to test intervention
  in all respects but is missing active ingredient
  under investigation

79
Sample size estimation

• ??????(sample size estimation)???????????????????
• ?????????,?????,??????????,??????????????????????
  ??????????????????????,?????????
• ??????????????????????????????,???????????????????
  ????????????????????100?,????????,???????????30??

80
Sample size

• ?Samples which are too small can prove nothing,
  samples which are too large can prove anything
  How big should my sample be ? has been likened
  to the question How much money should I take
  when I go on vacation? ( How long a vacant?
  Doing what? Where? Which whom? )
• ? Calculations of sample size require both
  decisions and surmises.

81
Optimal sample size

• Two-sided significance levela 0.05
• Power of the test, 1- ß 80, 90
• Clinically relevant difference d
• The standard deviation of the difference s
• N1N216 (s /d)2 a0.05, 1-ß80
• N1N221 (s /d)2 a0.05, 1-ß90

82
????

• ???? ??????????????????????????????????????????
  ??????????,?????????????
• ???? ??????????????????????????????????????????
  ???????????????????
• ???? ???????????????,?????????????????

83
????

• ???????????????(measurement variable)?????????????
  ???????????,???????????????????????????
• ??????????(categorical variable)??????????????????
  ?????????????????????????????????????????????????
  ??????????????????,??????????????,???????????

84
Scale for measurement

• Nominal scaleOrthodontic angles classification
• Marital status single, married, divorced,
  windowed
• Colour of hair red, yellow, black, green
• Types of Blood O, A, B , AB
• Ordinal scale plaque index Gingival Index, CPI
• Years of education 0, 1-5, 6-9, gt10
• Severity of disease mild, moderate,
  severity
• Interval temperature in Celsius temperature 22
  and 26, 32 and 36
• Ratio weight, mortality rate, DMFT

85
What are the different types of clinical trials?

• Treatment trials test experimental
  treatments, new combinations of drugs, or new
  approaches to surgery or radiation
  therapy.Prevention trials look for better ways
  to prevent disease in people who have never had
  the disease or to prevent a disease from
  returning. These approaches may include
  medicines, vaccines, vitamins, minerals, or
  lifestyle changes.Diagnostic trials are
  conducted to find better tests or procedures for
  diagnosing a particular disease or
  condition.Screening trials test the best way to
  detect certain diseases or health
  conditions.Quality of Life trials (or
  Supportive Care trials) explore ways to improve
  comfort and the quality of life for individuals
  with a chronic illness.

86
Study designs for clinical trials

• Historical comparison
• Parallel groups
• Factorial
• Cross-over
• Split mouth design

87
Ethical issues

• ? never conduct a study without a practical
  objective in view which will be of benefit to the
  community
• ? never conduct a study to assess treatment needs
  without discussing the criteria involved with
  those clinicians expected to carry out the
  identified treatment

88
Ethical Considerations

• ICH GCP requirements for the composition of the
  Ethics Committee (IRB)
• At least 5 members
• At least 1 member whose primary interest is
  non-scientific (lay member)
• At least 1 member who is independent of the trial
  site
• Only members who are independent of the
  investigator can vote or provide an opinion

89
What is informed consent?

• Informed consent is the process of learning the
  key facts about a clinical trial before deciding
  whether or not to participate. It is also a
  continuing process throughout the study to
  provide information for participants. To help
  someone decide whether or not to participate, the
  doctors and nurses involved in the trial explain
  the details of the study.
• Then the research team provides an informed
  consent document that includes details about the
  study, such as its purpose, duration, required
  procedures, and key contacts. Risks and potential
  benefits are explained in the informed consent
  document.
• The participant then decides whether or not to
  sign the document. Informed consent is not a
  contract, and the participant may withdraw from
  the trial at any time.

90
What are side effects and adverse reactions?

• Side effects are any undesired actions or effects
  of the experimental drug or treatment. Negative
  or adverse effects may include headache, nausea,
  hair loss, skin irritation, or other physical
  problems. Experimental treatments must be
  evaluated for both immediate and long-term side
  effects.

91
??????

• ???? ??????????????,?????????????????????????????
  ?????????1?1.23???????????????
• ???? ??????????????????????????
• ???? 34?????????,
• ????????? ?????,???????????????????????WHO???????
  ,?2???????????2?????????????????

H Jiang, Z Bian, BJ Tai, et al. The effect of a
Bi-annual professional application of APF foam on
dental caries increment in primary teeth
24-month clinical trial. J Dent Res,
200584(3)265-8.
92
???????????

• ???? NovaMin ?????????????????,????????????,?????
  ?????????????????6??????,??NovaMin????????????????
  ?????????????
• ???? ????????????????????????
• ????????? ??????(Silness Löe Plaque Index ,
  PLI) ???????(Gingival Bleeding Index,
  GBI)??????????????

Baojun Tai, Zhuan Bian, Han Jiang, et al.
Anti-gingivitis effect of a dentifrice containing
bioactive glass (NovaMin) particulate  J Clin
Periodontol, 2006 3386-91.
93
??????????

• ????????NovaMin??????????????????????????????????
  ????6??????NovaMin?????????????????????
• ???? ?????????????????????
• ???? Visual Analog Scale,VAS

Du MQ, Bian Z , Jiang H, et al. A
Clinical Evaluation of a Dentifrice Containing
Calcium Sodium Phosphosilicate (NovaMin) for the
Treatment of Dentinal Hypersensitivity. Jouranl
of Amercian Dental Assocaition, 2009
94
?????????

• ???? ?????????????????????????3?????(10?15?20)
  ?????????????,??????????,???????????????????????
• ???? ???????????????????????
• ????????? ??Vitalescence Esthetic Restorative
  Masters Shade Guilde (Ultradent
  ??)???????,???????????????????,???????????,??????3
  ??????,???????????????L?a?b??

Matis BA, Wang YN, Jiang T, et al. Extend
at-home bleachin of tetracycline-stained teeth
with different concetrations of carbamide
peroxide. Quintessence International, 2002,
33(9)645-655.
95
?????????

• ???????????????????????????????????????????,?????
  ?????????????????3??????????
• ???? ???????????????????????????
• ????????? ?????????????????,????????????????????
  ??1??,??3??????(???1.5???4.0????12.0??)4??????????
  ???????????????????????????,??2????????,??????????
  ?10?????????

96
????????

• ?????????????????????????,???????????????????????
  ???????????????,???????????????
• ???????????????????????????
• ???? ???????,???????,????????????????????????,??
  ?2???????
• ????????? ??????????X??,??????,?????????????

??, ???, ??,?. ??????????????????. ????????,2005,
38(3)192-195.
97
???????????

• ???????????????????????????????????????
• ??????Etoricoxib??????????????????????????????
• Etoricoxib??????????(COX)-2??????,????????????????
  ??????????????60mg?120mg?180mg?240mg?????Etoricoxi
  b????????????????????

98
New Law Requiring Registration at Clinical
Trials.gov

• On September 27, 2007, a US law was enacted that
  expands the types of clinical trials that must be
  registered in ClinicalTrials.gov, increases the
  number of data elements that must be submitted,
  and also requires submission of study results.

99
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