assess the efficiency of dental plaque control in decay teeth, gingivitis prevention for the 12 years- old pupils at some schools in the suburb of hanoi

1
MINISTRY OF EDUCATION AND TRAINING MINISTRY OF HEALTH
NATIONAL INSTITUTE OF HYGIENE AND EPIDEMIOLOGY
*



TA QUOC DAI







ASSESS EFFICIENCY OF DENTAL PLATE CONTROL IN
PREVENTION OF DECAY TEETH AND GINGIVITIS IN
12-YEAR-OLD PUPILS AT SOME SCHOOLS IN THE
SUBURBS OF HANOI





Major: Epidemiology
Code: 62 72 70 01

ABSTRACT OF DOCTOR OF MEDICINE THESIS






Hanoi - 2012

2

THE PROJECT WAS COMPLETED AT NATIONAL INSTITUTE OF
HYGIENE AND EPIDEMIOLOGY


Supervisor:

1. Associate professor. Doctor Trinh Dinh Hai

2. Doctor Dao Thi Dung

Opponent 1:

Opponent 2:

Opponent 3:

The thesis will be presented in the Institute – level Board of
Thesis Evaluation at National Institute of Hygiene and
Epodemiology

At … o’clock, day …… month ……. Year 2012




The thesis can be found at:
1. National library
2. Library of National Institute of Hygiene and
Epodemiology

3
ABBREVIATION
CPITN Community Periodental index of treatment needs
CI-S Calculus index simplified
II Intervention index
EI Efficiency index
ODC Oral and Dental care
IV Intervention
DI-S Debris index simplified
F Fluor
KAP Knowledge, Attitude, Practice
DP Dental plaque
SD School of dentistry
OR Odds Radio
OS Othodonto - Stomatology
OD Oral and Dental

QT Quantity
DT Decay teeth
DMFT Decay missing, filling teeth
PDT Permanent decay teeth
SS Secondary school
R Rate
G Gingivitis
ODH Oral and Dental Hygiene
WHO World Health Organization


4
INTRODUCTION

Decay teeth and gingivitis were two popular diseases among the oral
and dental diseases in the world as well as in our country. The diseases
could be suffered very early as soon as teething (6 months of old). If the
diseases were not treated timely, it could produce a side-effect in site or
the whole body, affecting to the physical and aesthetic development of the
child in the future.
In 20 recent years, thanks to the remarkable progress of science
technology, it was found that the reason and pathogeneswas of the oral and
dental diseases was caused by the dental plaque. Then the appropriate
preventive methods was found; however, the preventive methods for the
oral and dental diseases was very simple, not too difficult, did not require
the expensive equipments, the high professional technicians and the low
expenses, easy to implement in the community, in particular in the schools.
In 2001, according to the investigation results on the oral and dental
health national wide, there were 90% people suffered by the oral and
dental diseases, whereas the operation of the oral and dental preventive

network did not satisfy the requirements. Therefore, at the present, the oral
and dental prevention was the key mission of the Othodonto –
Stomatology major.
In Hanoi, the investigation results on the oral and dental health in 2007-
2008 with the pupils of primary and secondary schools showed that the
rate of oral and dental diseases were increased under the ages.
To strengthen the school of dentistry program, as well as find out the
new methods linking with the school of dentistry program aiming at
raising the quality, effectiveness of oral and dental diseases prevention for
the pupils, within the framework of the project “Assess the efficiency of
school of dentistry activities in Hanoi in 2009-2010 of National Institute of
Othodonto – Stomatology”, we researched the theme: “Assess the
efficiency of dental plaque control in decay teeth, gingivitis prevention
for the 12 years- old pupils at some schools in the suburb of Hanoi” to:

5
1. Describe the reality, some factors relating to the decay teeth,
gingivitis, dental plaque and knowledge, attitude, practice about the
oral and dental care for the 12 years-old pupils at some secondary
schools in Gia Lam, Quoc Oai District, Hanoi City in 2009.
2. Assess the efficiency of dental plaque control in the decay teeth,
gingivitis prevention for the 12-year-old pupils at 04 secondary
schools of two researched districts.

NEW CONTRIBUTIONS OF THE THESIS
1. The thesis provided the valuable reference information for the
specialized scientists about the oral and dental diseases, the oral and dental
care knowledge, attitude, practice and the reality of oral and dental care at
some secondary schools in the suburb of Hanoi.
2. The research result presented the effective intervention model to control

the dental plate, help the school medicine managers develop the effective
preventive methods for the decay teeth, gingivitis in the community.

STRUCTURE OF THE THESIS
The theswas had 125 pages; Introduction: 03 pages; Overview of
document: 34 pages; Subject and research method: 26 pages; Research
result: 34 pages; Discussion: 25 pages, Conclusion and Recommendation:
3 pages. There were 44 tables, 6 figures, 1 diagram and 4 charts in the
thesis. Besides, there were 139 documents in the reference, of which there
were 60 documents in Vietnamese and 79 documents in English; the
appendix section had 22 pages.

Chapter 1
OVERVIEW OF DOCUMENTS
The oral and dental diseases were the very popular diseases on the
world as well as in Vietnam, of which the decay teeth and gingivitis were
the most popular diseases. Previously, the decay teeth and gingivitis were
very popular in the developed countries due to the diet with much sugar
and milk. However, in the two recent decades, the reality of decay teeth in
two groups of countries (developed and developing countries) was
conversed. The rate of decay teeth in the developing countries was
increased due to lack of drinking water with fluoride, the diet with much
sugar, and the unvalued dental education. The developed countries
considered the dental education as the national policy, fluoride the

6
drinking water, implemented the diet with less sugar, used the toothpaste
with flour, filled the teeth slot so that the rate of decay teeth was
significantly reduced.
Previously, most of the countries in the world concentrated on the oral

and dental diseases treatment, recovered the chewing function and
aesthetic, so that it was very costly. Today, thanks to the remarkable
progress of the science technology, it was found that the reason and
pathogenesis of the dental diseases were caused by the dental plaque, and
then the preventive methods were very effective. In some countries, the
decay teeth, gingivitis was significantly reduced. Therefore, WHO
recommended that all the countries worldwide should prevent the oral and
dental diseases early at the age of pupil, which was the most feasible
strategy.
Vietnam was the developing country, in the recent years, the
socioeconomic situation has been developed, the nutrition had many
changes such as using much sugar, milk, etc, whereas the community was
not aware enough about the risks, evils as well as the preventive measures
for the oral and dental diseases. Many research works showed that in many
local areas, the oral and dental diseases tended to be increased, while the
operation of the oral and dental disease preventive network did not satisfy
the requirements. Therefore, at the present, the work of preventing the oral
and dental diseases was the key mission of the othodonto – stomatology
major.
To solve this situation, in many previous years, the othodonto –
stomatology major actively performed the mission of initial oral and dental
health care, of which the key mission was the school of dentistry work
with 04 contents: Educate dentistry for the pupils, use the gargle with 0,2%
flour weekly in the school, fill the teeth slot, examine and treat early the
oral and dental diseases in the school. However, the implementation and
effectiveness of this work were different under each group of ages, each
period. Partly, the reason was that the knowledge, attitude and practice of
the pupils on the oral and dental care were various under each period, each
place; so that the rate of oral and dental diseases for the pupils was still
high. The intervention researches showed that if the preventive measures

for the oral and dental diseases were implemented well, the rate of oral and
dental diseases would be significantly reduced. It was very practical to
strengthen the preventive measures for the oral and dental diseases,
particularly for the ages of pupil and useful to save the national budget,
reduce the burden for the Public Health Sector; reduce the costs for the
society to improve the public health.

7
On the national dentistry conference in 2010, according to the report
of National Institute of Othodonto – Stomatology, over 80% of people was
suffered by the oral and dental diseases, with the high rate of the disease as
today, if it only concentrated on the treatment and recovery without the
preventive treatment, it couldnot finish the endless treatment needs for the
community; the payable costs and budget were very big and it will lose
much time of the patients and doctors. However, at the present, the
network of othodonto–stomatology surgeries was very little, the group of
specialized doctors was not enough, the budget was narrowed. Despite
thanks to the socialization, a number of private hospitals, consulting-rooms
were significantly increased (but only in the cities), which solved a part of
treatment demand for the people; it still costs a lot of expenses, time of the
individuals and society. So that the prevention work of oral and dental
diseases was very important and essential. One of the important methods
in the oral and dental diseases prevention work was the Dental Plaque
control method.
The dental plaque or biofilm was one bacteria community living in
the organized structures in the interface between a hard side and liquid
existed in the teeth surface. The bacteria in the dental plaque lived in each
micro-cluster in one shape of extracellular polymer substances. By using
the PCR technology, it was found that there were 500 species of different
bacteria in the dental plaque. The dental plaque was considered as the most

important exotic agent in the oral and dental diseases. The dental plaque
could make the damages because of the two impact mechanisms: Direct
impact: Enamel made dental plaque become weak, disintegrate cell, peel
of many gummy tissues leading to gingivitis, prostaglandine destroyed
alveolar bone. Indirect impact: caused by bacteria and secretion of bacteria
as a antigen. These antigens stimulus the immune reactions ion site as well
as the whole body. Then, the intermediary products of the immune
reactions destroy the organization of gums. The capacity making the decay
teeth of the dental plate was based on its adhesion into the teeth, the
capacity making acid from C
12
and C
6
and pH of oral environment.
Methods to control the dental plaque: Mechanic methods: brushing
teeth, cleaning spaces between teeth, sprinkling method. Chemical
method: Use gargle for preventing and reducing the dental plaque with
flour to reduce the decay teeth, etc. Overcome and repair the errors:
Position of teeth, adjacent joints, repair the wrong teeth function.
Nutrition regime and preventive propaganda.

Chapter 2

8
SUBJECT AND RESEARCH METHOD

2.1. Subject, place and time of research
2.1.1. Research subject
- 12 years-old pupils, regardless of gender, were willing to join in the
research, excluding the pupils who change the school.

2.1.2. Research place, time:
- 6 secondary schools of Gia Lam and Quoc Oai Districts, Hanoi
- Research time: 5/2009 – 3/2011
2.2. Research method [32], [33], [34].
2.2.1. Research design
Cross-descriptive epidemiology methodology with analysis,
intervention epidemiology methodology with control.
2.2.1.1. Cross- descriptive epidemiology methodology
* Sample’s size
Sample’s size was calculated by the descriptive epidemiology formula
Z
2
1- /2
p (1-p ) p: 70%
n = x DE  = 0.05
d
2
DE: 2

According to the formula: n = 1008 (real research: 1022 pupils)
* Sampling method
Main purpose selection: + Quoc Oai District: Dong Quang, Thach Than
and Quoc Oai Town Secondary Schools
+ Gia Lam District: Co Bi Secondary School, Trau Quy Town and Da
Ton. To assure the medical ethics, took all pupils of 06 schools with 1022
pupils, examined dental and oral; interviewed KAP about oral and dental
care.
2.2.1.2. Intervention epidemiology methodology with control
* Sample’s size
Calculated by the fomula

Z
2
1 - /2
[(1 – p1)/ p1 + ( 1- p2)/ p2] p
1
: 80%
n
1
= n
2
= p2: 40%
[ln (1 - )]
2

: 15%,
According to the formula: n
1
= n
2
=259 (Real research of 02 groups:609)
* Sampling method
Among 6 secondary schools, we chose 04 schools and contigently
distributed into 2 groups, the intervention group with 2 schools, 306
puplis: Dong Quang- Quoc Oai District (156 pupils) and Trau Quy Town-
Gia Lam District (150 pupils), the comparison group with 02 schools, 303

9
pupils: Quoc Oai Town- Quoc Oai District (152 pupils) and Da Ton- Gia
Lam District (151 pupils).
2.3. Research contents:

2.3.1. Reality, some factors relating to the decay teeth, Gingivitis, dental
plaque and KAP about ODC for the 12 year-old pupils
- Identified the reality of the decay teeth, gingivitis, dental plaque for the
pupils
- Identified the reality of KAP of the pupils about oral and dental care
- Identified some factors relating to decay teeth , gingivitis
2.3.2. Assess the effectivess of dental plaque control in decay teeth,
gingivitis prevention for the 12 year-old pupils in 04 secondary schools
of 2 researched districts.
- Tested the dental plaque control intervention method for the research
subject: Cooperating 03 methods: dentistry education method, mechanic
method: guide brushing with supervision under the innovated Bass method
and chemical method (use gargle).
- Assessed the effectivess of dental plaque control by the oral and dental
diseases reality, by the PI debris indexes (using color indicator), CI-S
index, DI-S, OHI-S and KAP about the oral and dental care of the pupils.
2.4. Intervention assessement:
- Directly interviewed the pupils by questionaire
- Examined teeth of pupils (by bill of WHO) for assessement
- Assessed eefficiency index and intervention index:
Used efficiency index to assess some changed indexes (rate %) after
intervention in comparison with before intervention:
Efficiency index (EI) (%) =
/ p
1
– p
2
/

x 100

p
1


+ p
1
: Rate before intervention
+ p
2
: Rate after intervention
Used intervention index (II) (rate %) to assess the intervention effect
between the intervention group and the comparison group:
Intervention index (%) = Efficiency index (intervention group) –
Efficiency index (comparison group)
Compared the result of the collected indexes before and after intervention
and give the essential conclusions.
Chapter 3
RESEARCH RESULTS


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3.1. Reality of decay teeth, gingivitis, dental plaque, knowledge,
attitude, practice about oral and dental care and some factors related
to oral and dental diseases for the pupils
3.1.1. Reality of decay teeth, gingivitis and dental plate for the pupils
3.1.1.1. Reality of decay teeth

Table 3.1. Permanent decay teeth rate of the pupils under district
- Rate of pupils who were permanent decay teethof both two districts was
low 31.1%
3.1.1.2. Reality of gingivitis
Table 3.3. Number of pupils who were gingivitis under district
Gingivitis
Quoc Oai
(n = 510)
Gia Lam
(n = 512)
Total
(n = 1022)
QT Rate
(%)
QT Rate (%)

Qt Rate
(%)
Non-gingivitis (CPITN=0)

295

57.8 318

62.1 613

60.0
Gingivitis (CPITN = 1;2) 215

42.2* 194

37.9** 409

40.0
- CPITN =1 86 8.4 71 7.0 157

15.4
- CPITN =2 129 12.6 123 12.0 252

24.6
p
* - **
<0.05 (Quoc Oai and Gia Lam)
- Rate of gingivitis (CPITN=1.2) of the 12 years-old pupils in both two
districts was medium 40.0%.
3.1.1.3. Dental plaque reality of the pupils
Table 3.5. PI debris index reality of the pupils under district
Place

PI
≤ 2

PI > 2

QT % SL %
38,4
23,8
31,1
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
Rate (%)
Quoc Oai Gia Lam General
Research Places

11

Quoc Oai (n=510) 181 35.5 329 64.5
Gia Lam (n=512) 197 38.5 315 61.5
Total (n=1022) 378 37.0 446 63.0
p > 0.05
- The PI debris index of the pupils in the two districts had 02 different
levels; this difference did not mean statistic with p > 0.05.
Table 3.7. Dental debris reality of the pupils under district
Place
Level 0

Level 1

Level 2

Level 3
Qt % Qt % Qt % Qt %
Quoc Oai
(n=510)
25 4.9 41 8.0 401 78.6 43 8.5
Gia Lam (n=512) 24 4.7 38 7.4 392 76,6 58 11.3
Total (n=1022)
49

4.8

79

7.7

793

77.6

101

9.9

p>0.05

- The dental debris rate for the pupils in two districts was at the different
levels, ranked: Level 0, Level 1, Level 2, Level 3. The difference between
the rates of dental debris reality did not mean statistic (p >0.05).
Table 3.9. Calculus reality of the pupils under district
Place
Level 0

Le
vel 1

Level 2

Level 3

QT % Qt % Qt % Qt %
Quoc Oai (n=510) 81 15.9 247 48.4 143 28.0 39 7.7
Gia Lam (n=512) 112 21.9 330 64.5 58 11.3 12 2.3
Total (n=1022)
193

18.9

577

56.5

201

19.7

51

4.9


2

= 64.80 ; p <0.05
- The Calculus rate for the pupils in two districts was at the different
levels, ranked: Level 0, Level 1, Level 2, Level 3. The difference between
the rates of dental debris reality did not mean statistic (p >0.05).
3.1.2. Knowledge, attitude and practice about ODC of research pupils
3.1.2.1. Knowledge of Oral and Dental care
Table 3.15. the average mark of ODC knowledge of district’s pupils

Districts
Knowledge mark

Excellent

Good

Average

Amount

% Amount

% Amount

%
Quoc Oai (n=510) 79 15.5 87 17.0 344 67.5
Gia Lam (n=512) 108 21.1 122 23.8 282 55.1

12

Total (n=1022)
187

18.2

209

20.5

626

61.3


2

=13.75 ; p < 0.05
- Pupils had different marks of knowledge on ODC with statistic meanings
(p<0.05)
3.1.2.2. Attitude of ODC
Table 3.17. Pupil’s attitude of ODC (n = 1022)
Pupil’s

attitude of Oral and Dental care

Amount

%

It was needed to brush teeth after the main meals each day:
Agreed 389 38.1
Teeth must be examined periodically
Agreed 251 24.6
It was needed to visit doctor during tooth’s pain
Agreed 408 39.9
Used toothpaste to brush was a prevention method of DC
Agreed 429 42.0
- Pupils who agreed to brush their teeth, used toothpaste to brush and visit
doctor during teeth’s pain every day account 38.1%, 39.9% and 24.6%
respectively, the remaining percentage of pupils did not agree or did not
know
3.1.2.3. Practice about ODC
Table 3.18. Practice about ODC daily (n = 1022)
ODC Amount

Scale (%)
Method of oral and dental hygienve after the main meal

Brushed teeth

230 22.5
Number of teeth -brushing per day:

Many times

404 39.5
- After the main meal : 22.5%
- Number of teeth- brushing per day: 39.5%.





Table 3.20. Time to brush and change the tooth brush (n = 1022)
Index Amount

Scale (%)
Time to brush each time
- more than three minutes

309 30.2
Time to change tooth brush:


- 3 months

332 32.5

13

-The number of pupils who brushed their teeth under the regulated time
(more than three minutes) only accounted for 30.2% and 32.5% was the
scale to change their tooth brush timely ( three months one time)
Table 3.23. Oral and dental care after Eating, drinking sweet food and

beverage and beverages (n=1022)
Index

Amount

Scale (%)

Number of time of eating, drinking sweet food and beverage and
beverages each day:
- Many times

703 68.8
Oral and dental hygience after eating, drinking sweet food and beverage
and beverages
- Brushed their tooth

42 4.1
- 68.8% of pupils ate and drunk sweet food and beverage and beverages
(biscuit, sweet, cream, pepsi, etc.) many times per day. Only 4.1% of them
followed to brush their teeth after eating and drinking.
Table 3.24. To take a latest visit to dentist for teeth examination
(n=1022)
Index (time)

Amount

Scale (%)

- From 6 to 12 months 204 20.0
- Only 20% Pupils followed to visit doctor for periodical teeth

examination.
3.1.3. The relationship between ODH and DT and Gingivitis of pupils
Table 3.27. Relationship between ODH and PDT
ODH
PDT
OR; p
Yes

No
Amount

(%)

Amount


(%)

Not good 231 22.6 342 33.5 OR=2.8
p < 0.05
Good 87 8.5 362 35.4
Total

318

31.1

704

68.9

- There was a close relationship between oral and dental hygiene and
Permanent DT with OR=2.8; P<0.05
Table 3.28. Relationship between ODH and Gingivitis
ODC
Gingivitis
OR; p
Yes
No
Amount

(%) Amount

(%)
Not good 291 28.5 282 27.6 OR = 2,9

14

Good 118 11.5 331 32.4 p < 0.05
Total

409

40.0

613

60.0

- There was a close relationship between ODH (good or not good) and O
(yes; no) with OR=2.9; p<0.05
3.2. Assess DP control efficiency in DT and G prevention to Pupils
3.2.1. DP control efficiency in the prevention of DT and G to Pupils
3.2.1.1. Dental plate control efficiency
Table 3.29. Plate Index (PI) in two group of pupils
PI
IV group


Comp
arison
group

p

EI
IV Group

II (%)
Before
(1)
After

(2)
Before

(3)

After

(4)
PI ≤ 2
QT 113 265 112 102 p
1-2
<0.01

p
2-4
<0.01

134.5
125.6
% 36.9 87.7 36.7 34.0
PI > 2
QT 193 37 191 198 p
1-2
<0.01

p
2-4
<0.01

80.8
77.1
% 63.1 12.3 63.3 66.0
- PI ≤ 2 after IV of IV group increased clearly in comparison with pre-IV
(EI =134,5%, p<0.01). In the comparison group, PI ≤ 2 decreased (II =
125,6%).

Table 3.30. Number of pupils with dental debris in two research groups
Debris
IV group

Comparison
group

p
EI
IV Group

II (%)
Before
(1)
After
(2)
Before

(3)
After

(4)
Level 0
QT 14 134 15 11
p
1-2
<0.01

p
2

-
4
<0.01

857.1
885.7
%

4.6 44.4 5.0 3.7
Level 1
QT 24 168 23 16
p
1-2
<0.01

p
2
-
4
<0.01

600.0
630.4
% 7.8 55.6 7.6 5.3
Level 2
QT 237 0 235 211

100.0
110.2
% 77.5 0 77.6 70.3

Level 3
QT 31 0 30 62

% 10.1 0 9.9 20.7
- After IV of IV group, Level 0 increased clearly in comparison with pre-
intervention (EI=857.1%) and in the comparison group, level 0 decreased
II=885.7%). After IV, Level 1 increased clearly in comparison with pre-
intervention (EI=600.0%, p<0.01%), meanwhile, in the comparison group,
level 1 decreased (II= 630.4%).
Table 3.31. Number of pupils with calculus

15

Calculus
IV Group


Comparison
group

p
EI
IV Group

II (%)
Before
(1)
After

(2)

Before

(3)
After

(4)
Level 0

QT 58 63 57 41
p
1-2
>0.05
p
2-4
<0.05
8.6
36.7
%

19.0 20.9 18.8 13.7
Level 1
QT
172 176 171 177
p
1-2
>0.05
p
2-4
>0.05
2.3

1.2
% 56.2

58.3

56.4 59.0
Level 2
QT
61 48 62 65
p
1-2
>0.05
p
2-4
>0.05
21.3
26.1
% 19.9 15.9 20.5 21.7
Level 3
QT
15 15 13 17
p
1-2
>0.05
p
2-4
>0.05
0
30.8
% 4.9 4.9 4.3 5.6

After IV of IV group, Level 0 increased clearly in comparison with pre-
intervention (EI=8.6%, p>0.05) and in the comparison group, level 0
decreased II=36.7%).
After IV, Level 1 increased clearly in comparison with pre-intervention
(EI=2.3%), and in the comparison group, level 1 lightly increased (II=
1.2%).
3.2.1.2. Preventive efficiency of DT

Diagram 3.4. Permanent DT scale in two groups of pupils
Remark:
IV group: before intervention, 95 (31.0%) pupils out of (306 pupils) got
DT, after intervention, 95% pupils out of (302 pupils) got DT (31.5%).
Comparison group: before IV, 94 pupils (31.0%) out of (303 pupils) got
DT, after 12 months 118 pupils (39.3%) out of 300 pupils got DT.
After IV, DT scale in the IV group was lower than that of the comparison
group with the meaning of statistics (p<0.05)

16

3.2.1.3. Preventive efficiency of gingivitis
Table 3.35. Number of pupils gets gingivitis

O
IV group
Comparison
group

p
EI
IV Group

II (%)
Before
n=306

(1)
After

n=302

(2)
Before
n=303

(3)
After

n=300

(4)
No gingivitis
(CPITN= 0)
QT

183 239 182 162

%

59.8 79.1 60.1 54.0
gingivitis

(CPITN = 1;2)

QT

123 63 121 138 p
1-2
<0.05

p
2-4
<0.01

48.8
62.8
% 40.2 20.9 39.9 46.0
- O scale after IV of IV group clearly increased in comparison with pre-IV
(EI=48.8%), meanwhile,O scale in the comparison group increased
( II=62.8%).
3.2.2. Efficiency for KAP about ODC of pupils
3.2.2.1. Efficiency for knowledge about ODC of pupils
Table 3.38. The average mark about ODC knowledge of two pupil groups
Mark of
knowledge
IV group

Comparison
group

p

EI
IV Group

II (%)
Before
(1)
After
(2)
Before

(3)
After

(4)
Excellent
QT 55 125 56 57 p
1-2
<0.01
p
2-4
<0.01
127.3
125.5
% 18.0 41.4 18.5 19.0
Good

QT 62 135 64 92 p
1-2
<0.01
p

2
-
4
<0.05
117.7
74.0
% 20.3

44.7

21.1

30.7

Average

QT 189 42 183 151 p
1-2
<0.01
p
2-4
<0.05
77.8
60.3
% 61.8

13.9

60.4

50.3

- Scale of pupils with excellent knowledge after IV of IV group clearly
increased in comparison with pre-IV ( EI= 127.3%, p<0.01) meanwhile
comparison group slightly increased ( II= 125.5%).
- Scale of pupilswith good knowledge after IV of IV group clearly
increased in comparison with preintervention ( EI= 117.7%, p<0.01)
meanwhile comparison group slightly increased (II= 74.0%).
3.2.2.2. Efficiency for attitude of ODC
Table 3.39. Attitude of two groups of pupils about ODC
Attitude of
pupilsabout
IV group


Comparison
group

p

EI

IV Group


17

ODC

Before

(1)
After
(2)
Before

(3)
After

(4)
II (%)

Daily teeth brush after the main meal


Agreed

QT
116 250
118 145 p
1-2
<0.01
p
2-4
<0.05

115.5
92.6
%

37.9

82.8

38.9

48.3

Examine teeth periodically

Agreed

QT
75 243
73 80 p
1-2
<0.01
p
2-4
<0.05

224.0
214.4
%

24.5

80.5

24.1

26.7

Used toothpaste to brush was preventive method of oral and dental desease
Agreed
QT
128 272
127 151 p
1-2
<0.01
p
2-4
<0.05

112.5
93.6
%

41.8

90.1

41.9

50.3

- Agreement attitude of pupils about daily tooth brush after the main meal
clearly increased in comparison with pre-IV (EI=115.5%, p<0.01) and II in
the comparison group was 92.6% after IV of IV group.

- Agreement attitude of pupils about periodical tooth examination after IV
clearly increased in comparison with pre-I (EI=224.0%, p<0.01) and II in
the comparison group was 214.4%.
- Agreement attitude of pupils about using toothpaste to brush was a
preventive method of oral and dental desease. After IV, Scale of pupils
agreed to brush as a preventive method of oral and dental decrease clearly
increased in comparison with comparison group (II=93.6%)









3.2.2.3. Efficiency for practicing ODC of student
Table 3.40.Practicing ODC daily of two groups of pupils
ODC
IV group


Comparison
group

p

EI
IV Group

II (%)
Before
(1)
After
(2)
Before
(3)
After

(4)
Method of oral and dental hygiene after the main meal:
Brush QT 67 228 64 70 p
1
-
2
<0.01 240.3

18

teeth % 21.9

75.5

21.1

23.3

p
2
-

4
<0.05

230.9
Number of tooth brush/ one day:
Many
times
QT 122 279 121 160 p
1-2
<0.01
p
2-4
<0.01

128.7
96.5
% 39.8

92.4

40.0

53.3

- The correct tooth brush practice after the main meal clearly increased in
comparison with pre-IV (EI=240.3%, p<0.01) and II in the comparison
group was 230.9%
- Practice to brush teeth many times per day of pupils after intervention of
IV group clearly increased in comparison with pre-I EI=128.7%, p<0.01)
and II in the comparison group was 96.5%

Table 3.42. Time to brush and change teeth of two groups of pupils
Index
IV group


Comparison
group

p

EI
IV Group

II (%)
Before
(1)
After
(2)
Before
(3)
After

(4)
Time to brush teeth each time
More than 3
minutes
QT 93 226 92 122 p
1-2
<0.01
p

2-4
<0,.05

143.0
110.4
% 30.4 74.8 30.4 40.7
Time to change tooth brush
3 month
each time
QT 98 223 97 114 p
1-2
<0.01
p
2
-
4
<0.05

127.6
110.1
% 32.0 73.8 32.0 38.0
- Practice to brush more than 3 minutes per time after IV of IV group
clearly increased (EI= 143.0%, p<0.01). After intervention, scale of pupils
practices to brush more than 3 minutes per time of IV group clearly
increased in comparison with comparison group (II= 110.4%)
- Time to change tooth brush 3 month per time of pupils after intervention
of IV group clearly increased in comparison with preintervention
(EI=127.6%, p<0.01). After intervention, scale of pupils changing their
tooth brush 3 months/time increased much more than that of the
comparison group (II= 110.1%)

Table 3.43. Eat, drink sweet food and beverage and the ODC after eating, drinking
sweet food and beverage and beverage of two groups of pupils
Index
IV Group


Comparison
Group

p

EI
IV Group

II (%)
Before

(1)
After

(2)
Before

(3)
After

(4)
The number of times of eating, drinking types of sweet food and beverage/
day:
QT 211 116 209 180 p

1
-
2
<0.01 45.0

19

Many
times
% 69.0

38.4

69.0

60.0

p
2-4
<0.05

58.9
Protecting teeth, mouth after eating, drinking types of weet food:
Brushed
teeth
QT 15 156 13 16 p
1-2
<0.01
p
2

-
4
<0.05

940.0
916.9
% 4.9 51.7 4.3 5.3
- The rate of pupils who ate, drunk sweet food and beverage many
times/day after the IV of IV Group significantly reduced in comparison
with the before-IV rate (EI = 45.0%, p < 0.01). After IV, the rate of IV
Group’s the pupils who ate, drunk types of sweet food and beverage many
times/daysharply reduced in comparison with that of the Comparison
Group (II = 58.9%).
- The rate of pupils who brushed the teeth after eating, drinking types of
sweet food and beverage after IV of IV Group significantly increased in
comparison with the before-IV rate (EI= 940.0%, p < 0.01). After IV, the
rate of IV Group’s pupils who brushed the teeth after eating, drinking
types of sweet food and beverage significantly increased in comparison
with that of the Comparison Group (II= 916.9%).
Table 3.44. Examine and treat teeth in the latest time of two groups of pupils
Index
(Time)
IV Group

Comparison
Group

p

EI

IV Group

II (%)
Before

n=306

(1)
After

n=302

(2)
Before

n=303
(3)
After

n=300

(4)
6 to 12
months
QT 58 183 57 66 p
1-2
<0.01
p
2-4
<0.001

215.5
199.7
% 19.0

60.6

18.8

22.0

- The rate of pupils who went to the dentist for dental examination in the
latest time, from 6 – 12 months after IV of IV Group significantly
increased in comparison with the before-IV rate (EC = 215.5%, p < 0.01).
After IV, the IV Group’s rate of pupils who went to the dentist for dental
examination in the latest time, from 6 -12 months significantly increased in
comparison with that of Comparison Group (II = 199.7%).

Chapter 4
DISCUSSION
4.1. The reality of the DT, G, DP, KAP on ODC and some factors
related to OD diseases of the pupils.
4.1.1. The pupils’s reality of the DT, G, DP
4.1.1.1. The Decay teeth’s reality

20

The result of research showed that the PDT rate of the group of pupils
in general research in two districts was low, at 31.1%, which was
represented in Table 3.1. Of which, the PDT rate of Quoc Oai District’s

pupils (38.4%) was higher than that of Gia Lam District’s pupils (23.8%).
The differnce on the PDT rate between 2 districts was meaningful in the
statistics (p <0.05), this result showed that this rate was lower in
comparison with that of Duong Thi Truyen in An Giang (2005) with the
PDT rate of 6.,2%, in comparison with the rate given by Trinh Dinh Hai
(2008) in this research applied for the 12-14 year old pupils, specifically
the result was: 43.1% DT, DMFT Index: 1,12, in comparison with that of
Chu Thi Vân Ngoc (2008): 53.2% DT, DMFT Index: 1.48. However, it
was higher than the rate in Dao Thi Dung’s research applied for 12 year
old pupils and after Hanoi extended in 2009, the rate was:15.3%. The
reason for this difference might be that these schools had well conducted
the programs of School of Dentistry.
4.1.1.2. The Gingivitis’s reality of the pupils:
The general O reality of the 12 year-old pupil group in two districts
was 40%, at the average level according to WHO’s rank. For the pupils of
Quoc Oai District, this rate (42,2%) was higher than that of Gia Lam
District (37.9%). The difference between the gingivits rate in two districts
was meaningful in the statistics (p < 0.05). For the pupils whose CPITN =
1, the intervention for this group was more simple and the efficiency was
also gained more quickly and easier, we only needed to instruct the pupils
to do ODH in proper way, the gingivitis’s organ was healthy again. For the
pupils whose CPITN = 2 , to treat this group, it required the IV to take
dental plaque. As such, there was 24,7% pupils who needed to take dental
plaque in order to treat the gingivitis’s situation.
Nguyen Dang Nhon’s research results in 2004 showed that the gingivitis
rate: 62.5%. In 2008, Chu Thi Vân Ngoc researched and showed the
gingivitis result is: 64.7% . The rate in this result was higher than our
result of research. The author Le Ba Nghia researched the gingivitis rate in
2009 at: 29.8%. In 2008, Đao Thi Dung’s research showed that the
gingivitis rate: 6.10% and this result was lower than our research result.

4.1.1.3. The dental plaque’s reality of the pupils
According to the WHO’s rank: PI ≤ 2: ODH was good; PI > 2: ODH was
not good; Such as, the pupils whose ODH was not good account for
63.0%, while the studetns whose ODH was good accounted for 37.0%. In
the period of new establishment, DP was the colorless thin film, therfore,
through the clinical way, it was hard to discover it by normal oral and
dental examination methods. To identify the reality of DP and ODH of the

21

pupils, we had to conduct the method of dental plate dyeing by eosin 2%.
By this way, the students’ bad ODH reality was appreciated according to
the PI and it was higher than that was appreciated according to the OHI-S.
4.1.2. The pupils’KAP on ODC
4.1.2.1. The pupils’knowdges on ODC:
According to research result in Table 3.15, the pupils in 2 districts
had the rate of knowledge marks on ODC at different levels, ranking in the
high-low order. Average: 61.3%, Credit: 20.5%, Good: 18.2%, the
difference on the knowledge mark level was meaningful in statistics
(p<0.05),.
4.1.2.2. The attitude on ODC of the pupils
In the Table 3.17, it was shown that only 38.1% children agreed to
brush teeth after the main meal. Such as, they had not clearly understood
the benefits of brushing teeth in ensuring the oral and dental health,
therefore, they had improper attitude on this issue.
4.1.2.3. Practising on ODC of the pupils
Regarding on the teeth brushing practice after meal, currently, just
22.5% brushed teeth by the toothbrush after main meal. The result in Table
3.17 showed that there was 38.1% pupils who agreed to brush teeth after
the main meal. This showed that there was huge gap between attitude and

practice. Regarding on time of teeth brush one time: Just 30.2% pupils
brushed teeth for over 3 minutes. This showed that they had not known the
important effects of brushing teeth to prevent the oral and dental diseases
(time of teeth brushing ≥ 3minutes was needed for fluor from the
toothpaste to absorb into the dental cement to make dental cement stronger,
better resistance againt DT)
4.1.3 The connection between the ODH situation and DT, G
The result of Table 3.27 showed the close connection between the ODH
and DMFT. The pupils who did ODH not well had risk of PDT, 2.8 times
as much as the pupils who did ODH well with OR=2.8; p<0.05. The result
of Table 3.28 showed that the close connection between ODH situation
and the gingivitis disease. The pupils who did ODH not well had the risk
of the gingivitis at the level of 2.9 times as much as the pupils who did
ODH well with OR = 2.9; p < 0.05.
4.2. Evaluate the DP control efficiency in the DT and gingivitis
prevention of the pupils
4.2.1. Evaluate the DP control efficiency in the DT and gingivitis
prevention of the pupils
4.2.1.1. Evaluate DP control efficiency

22

The PI demonstrated through Table 3.29 showed that: The PI ≤ 2 after IV
of IV Group significantly increased in comparison with the before-IV rate
(EI = 134.5%, p < 0.01), while the PI of Comparison Group reduced. This
showed that the intervention was effective with II= 125.6%. The index of
the residue sticking to the teeth demonstrated in Table 3.30 showed that:
The rate of level 0 after IV of IV Group significantly increased in
comparison with the before-IV rate with II = 857.1%, p< 0.01. On the
contrary, in the Comparison Group: the rate of level 0 after 12 months

reduces; therefore, the intervention was very effective with II= 885.7%.
Such as, the students’ index of residue sticking to teeth was significantly
improved while in the comparison group , after 12 months, the index of the
residue sticking to teeth increased every day appropriately with the age,
which proved the intervention was very effective.
Tran Thu Thuy and the base of instructing the pupils to brush teeth within
2 months showed that the DI-S reduces in comparison with the
Comparison Group , which had the meaning of statistics (p<0.05).
The dental plaque index in Table 3.31 showed: The rate of level 0
after IV of IV Group increased in comparison with the before-IV rate with
EI = 8.6%, p > 0.05. After 12 months, the rate of level 0 in the Comparison
Group reduced, therefore, the intervention was effective with II = 36.7%.
Such as, the dental plaque index of the pupils under the IV Group
was partly improved while the dental plaque situation of the Comparison
Group after 12 months increased according to the age; therefore, the
intervention was effective.
According to Chibinski AC, PochapskiMT. et al, applying the
chemical method (mouthwash) for the children from 7-12 years old; the
result showed that the DP and G bleeding reduced. The authors Ersin NK,
Eden E. et al utilised the chemical methods for the children from 11- 13
years old and the result showed that DP was reduced and ODC was
controlled. Our research result was similar to the research results of two
above authors.
4.2.1.2. Evaluate the efficiency of DT prevention
The result of the Table 3.4 showed the efficiency of DP control by
the mechanic and chemical methods for the DT: In the IV Group, DT rate
did not increase but in Comparison Group, the DT rate increased from
31.0% to 39.3%. After the intervention, the DT rate in the IV group was
lower than that in the Comparison Group, which brought the meaning of
statistics (p < 0.05). Such as, after one year of DP control, in the IV Group,

the DT was controlled with no increase of the number of decayed teeth.

23

The Comparison Group of the DT continued to increase appropriately with
the age and exposure time.
We knew that the permanent teeth started to appear when we were 6
years old; During time from rising teeth to the age of 12, 13 years old, it
was easy for the teeth to be decayed because the enamel had not been
improved and easily destroyed by acid enviroment. On the other hand,
when teeth had already risen, the hole in the teeth was often narrow and
deep; the food was easily blocked and it was hard to clean them, especially
the children at this age often ate nosh. These factors created the favorable
conditions to cause the DP. The bateria on DP converted the substance
with gluxit origin to make acid and destroy the enamel, which caused the
DT. When having DT and gingivitis, it became more difficult to clean the
DP. This pushed up the DT and gingivitis.
The dentistry education for the pupils included instructing the teeth
brush in proper method and reasonable eating regime, which played the
important role in limiting the DP creation. In addition, we also conducted
to intervene by chemical method: Let the children clean their mouth by
colgate Plax mouthwash twice/day, keep it in the mouth for 30s/each time.
The colgate Plax mouthwash had function to control the bacteria to limit
the bacteria in the mouth, prevent the settlement of the bacteria in the
teeth’s surface, prevent the DP creation, dissolve the established DP,
prevent the DP mineralization. As the result, the DP was reduced and then
the DT was reduced. Such as, the methods of interventions were simple,
however; it created simultaneous impacts on the biological dissease factors
causing the DT, namely: enamel, DP, bacteria and sugar (gluxit) and had
the function to prevent the DT effectively.

4.2.1.3. Evaluate the efficiency of the gingivitis prevention
After IV: The gingivitis rate of IV Group significantly reduced while
this rate increased in the Comparison Group. This showed that the
intervention with II = 62,8% was very effective. After the intervention, the
gingivitis-bleeding rate of IV Group ended while this rate of Comparison
Group increased by 19.0%. The method of intervention was very effective
with II= 121.3%.
Comparing the result of DP index with the result of evaluating the
situation of oral and dental disease at the equivalent groups, it was shown
that there was the close connection between DP situation and oral and
dental diseases. In the intervention of DP index, the gingivitis rate was also
high. After the intervention, the DP situation was controlled significantly
and the DT was controlled with no increase. The DP control made

24

important contributions to reduce the DT and gingivitis diseases of the
pupils.
The author Trinh Dinh Hai used the method of dentistry education, clinical
prevention (take the enamel, provisional coating, etc), within 8 years, the
gingivitis rate reduced by 50.0%. The result of our research applied for 12
year-old pupils in one year with the method of DP control showed that the
gingivitis reduced by 20.0%, the DP reduced (because some pupils had the
enamel at the level: 2; 3; therefore, it was needed to take the enamel, the
gingivitis would end) and then the DT was controlled.
4.2.2. Evaluate the efficiency for the pupils’KAP on the ODC
4.2.2.1. Evaluate the efficiency for the pupils’ knowledge on ODC
Through the students’ knowledge intervention, IV Group on ODC
significantly increased in comparison with the pupils at the same age of the
control group, it was stated that the intervention was very effective (The

pupils who had good knowledge mark significantly increase with II =
125.5%, the pupils had the increasing knowledge mark with II = 74.0%).
After 7 months of interveing for the pupils of grade 5 in
Thai Binh, The author Nguyen Tien Vinh showed that the knowledge on
oral and dental issue increased to the good mark of 7.8 from the average
mark of 6.9.
4.2.2.2. Evaluate the efficiency for the students’attitude on ODC
After 12 months of intervention, it showed the obvious efficiency for
the pupils of IV group and they had the attitude of changing properly, for
ODC. When the pupils had proper awareness and attitude, they would had
proper practice skills to care the teeth and mouth better. .
By studying the oral and dental disease for the pupils of the ethnic
group in Yen Bai, Dao Thi Ngoc Lan states that after intervention, the
knowledge, attitude, practice of the students on ODC were significantly
increased and the education gained the efficiency; the research results of 2
above authors was also similar to our research result.
4.2.2.3. Evaluate the efficiency for the students’practice on ODC
After the invention, the pupils in the IV Group had positive change on
ODC practice. This showed the obvious effciency of the intervention. As
the result, the rate of pupils infected to the oral and dental disease sharply
reduces.
In short, the intervention changed the rule of natural development of
oral and dental disease. For the DT disease, the rate of DT and DMFT
were permanently limited and the accelaration speed according to the age
was controlled. For the gingivitis disease, the rate of the gingivitis
infection was lowered and CPITN 2 accelaration according to the age was

25

controlled. The intervention had the function to increase the rate of pupils

with ≥ 3 healthy hexadecimal areas at the acceptable level from 59.2% to
83.0%. In addition, the intervention increased the PI ≤ 2 and reduced the
indexes: DI-S, CI-S, ODH index and changed the rule of natural progress
according to these’s indexes. The result of DP control in the group of
pupils was intervened, which contributed to explain the obtained results in
reducing the oral and dental diseases of the pupils in the group of
intervention and then affirmed that DP control was obviously effective in
preventing the DT and gingivitis

CONSCLUSION
1. The reality of DT, G and DP; knowledge, attitude, practice on the
ODC and some factors related to the pupils’ oral and dental disease.
- The reality of DT, Gingivitis: The common rate of permanent DT of
12 year-old pupils in two districts was low, at: 31.1% (Quoc Oai: 38.4%,
Gia Lam: 23.8%; p <0.05). The DMFT index of 12 year old pupils in two
districts was low, at: 0.93 (Quoc Oai: 1.10, Gia Lam: 0.76). The common
gingivitis rate of 12 year old pupils was at the average level: 40.01%
(Quoc Oai: 42.2%, Gia Lam: 37.9%; p <0.05).
- The DP’s reality:
PI: PI ≤ 2, accounted for 37.0%; PI >2 accounted for 67.0%.
The index DI-S: Good: 12.5%, Not good: 87.5%. The index CI-S: Good:
75.4%, Not good: 24.6%.
The rate of pupils whose ODH was not good: H56.1% (Quoc Oai: 61.4%,
Gia Lam: 50.8%;p<0.05). Good: 43.9% (Quoc Oai: 38.6%, Gia Lam:
49.2%).
- The pupils’ KAP on the ODC: The credit and good knowledge
capacity was low; the average knowledge: 61.3%. The proper attitude
accounted for low rate: 38.1% on agreeing to daily brush after main meal.
Practice: The rate of pupils who brush teeth after main meal was low,
22.5%; there was only 4.1% pupils who brush teeth after eating the sweet

food; there was only 20% of the pupils who go for periodical teeth
examination.
- Some factors related to the DT, Gingivitis: Got the close connection
between oral and dental hygiene care and the DT & gingivitis disease. The
pupils whose ODH was not good had the risk of permanent DT with 2.8
times and the gingivitis with 2.9 times in comparison with the pupils
whose ODH was good.
2. Evaluate the efficiency of DP control in the DT& G prevetion of the
pupils.