Abstract of medical PHD thesis: Research on the prevention of incipient caries with fluorideoral rinsing solution for 7-8-year-old pupils in Phu Tho province

The proceed subject with two purposes: Determine icipient caries in permanenr teeth and related factors in 7-8 year old pupils at Dinh Tien Hoang and Tan Dan schools in Phu Tho, 2015. Assess the efficiency of prevention and treatment of incipient caries in permanent teeth by the use of 0.05% fluorideoral rinsing solution on pupils 7-8 years after 18 months.

MINISTRY OF EDUCATION AND TRAINING MINISTRY OF DEFENCE

108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES

-

TRAN THI KIM THUY

RESEARCH ON THE PREVENTION OF INCIPIENT CARIES WITH FLUORIDE ORAL RINSING SOLUTION FOR 7-8 YEAR-OLD PUPILS IN PHU THO PROVINCE

Speciality: Odonto Stomatology

Code: 62720601

ABSTRACT OF MEDICAL PHD THESIS

Hanoi – 2019

THE THESIS WAS DONE IN: 108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES

Supervisor:

1 Prof PhD Trinh Dinh Hai

2 Ass Prof PhD Le Thi Thu Ha

Day Month Year

The thesis can be found at:

1 National Library of Vietnam

2 Library of 108 Institute of Clinical Medical and

Pharmaceutical Sciences

A- THESIS INTRODUCTION RESEARCH STATEMENT

Dental caries has worldwide, and besides periodontal disease, been considered as one of the two leading burdens for dental healthcare According to the WHO (World Health Organisation) oral and dental healthcare report in 2003, dental caries has presented impact on 60-90% pupils, and almost adults, in a big number ofindustrial countries, with the highest incidence in some Asian and Latin America countries In Vietnam, the incidence has been maintained at a high level, and tended to increase, especially in rural and mountainous areas

The role of fluoride, in general,and of fluoride oral rinsing solution,

in particular, has been known and recognized as a means toreduce incidence and seriousness of dental caries A research by Marinho et al (2003), through a general analysis of intervention research, indicates that fluoride0.05% oral rinsing solutionreduces 45% dental caries rate (95%CI: 0.35 - 0.50) These studies, however, have many limitations such as not providing an optimal using method (with high efficiency, safety, and convenience) or suggestingan optimal dosage for each stage

1 Determine icipient caries in permanenr teeth and related factors

in 7-8 year old pupils at Dinh Tien Hoang and Tan Dan schools

in Phu Tho, 2015

2 Assess the efficiency of prevention and treatment of incipient caries in permanent teeth by the use of 0.05% fluorideoral rinsing solution on pupils 7-8 years after 18 months

THE URGENCY OF THE RESEARCH

The understanding of dental carious pathotogy, especially during early stages, has been neglected to some extent Elements relating to dental caries, methods of detection, diagnosis and prevention by fluorideoral rinsing solution to maintain permanent healthy teeth is essential

Establishing a proper plans for preventing and treatment dental caries during the early stage of permanent teeth eruption, many updated data as well the specific efficiency of 0.05% fluorideoral rinsing solution

on carious lesions are need to be studied

PRACTICAL MEANING AND NEW CONTRIBUTIONS

1) Update the incidence of incipient caries in permanent teeth and detect some factors related to dental caries in 7-8 year old pupils

2) Effectiveness of 0.05% fluorideoral rinsing solution in prevention and treatment to demineralization incipient caries in permanent teeth (D1, D2) is very high

3) Changing diagnosis criteria according to ICDAS system will help managers with giving more effective methods to prevent dental caries 4) A simple, safe and low cost fluorideoral rinsing solution programme should be planned during primary school

THESIS STRUCTURE

The thesis consists of 4 chapters: Chapter I: Overview, 35 pages Chapter II: subjects and research methods 25 pages Chapter III Research results 36 pages.Chapter IV: 35 pages discussion The thesis has 35 tables, 03 diagrams, 08 charts, 23 figures, 111 references, (27 in Vietnamese, and 84 in English)

B THESIS CONTENT CHAPTER 1 AN OVERVIEW 1.1 Characteristics of primary dentition, permanent dentition and pediatric oral pathology

1.1.1 Characteristics of teeth and permanent teeth: There are 4 stages

From Embryonic stage to 3 years old: fully erupted primary teeth From 3-6 years old stage: primary dentition

From 6-12 years old: mixed dentition

From 12-18 years old: permanent dentition

1.1.2 Microscopic characteristics of tooth enamel:

In children, the distance between the enamel prism is big because the calcification stage has not finished, whereas in adults, the mineralization process is completed, it is impossible to find the space

1.1.3 Characteristics of pediatric oral pathology

The typical dental diseases in children are related closely to diet, oral hygiene and oral prophylaxis

1.2 Understandings about dental caries and early stage dental caries

1.2.1 Definitions of dental caries:

- Caries is infection of the hard tissue of the teeth, characterized by demineralization of inorganic components and destruction of organic components

- Early childhood caries (ECC) in children is the presence of one or more deep carious lesions (already form into holes or not yet) on any primary teeth in 71 months old children or younger

-Incipient caries is a reducing pH process which lead to demineralization that enhances the distance between hydroxy apatite crystals, demineralization starts under the enamel surface, clinical carious lesions is lost 10% of minerals

1.2.2 Etiology of dental caries

Dental caries is a multifactorial disease

1.2.3 Physiology of dental caries

1.2.4 Progression of carious lesions:

The time for a lesion to progress from incipient caries to clinical deep hole take several months up to over 2 years, depending on the balance between demineralization and mineralization

1.2.5 Classification of dental caries:

Classification by "site and size", by Pitt's diagnostic threshold and

by ICDAS are often applied in scientific research and community

1.2.6 Diagnosis of dental caries:

There are many methods used to diagnose dental caries, each methods have different diagnostic threshold and different diagnostic criteria such as: visual examination, bitewing x-ray, electronic checking machine (ECM), Fluorescent laser diagnosis (DIAGNODENT), digital imaging fiber optic transillumination (DIFOTI), Quantitative Light-induced of fluorescence (QLF), caries detection dyes, digital photos

1.2.7 Epidemiology of dental caries and early stage dental caries in children

1.2.7.1 Worldwide: early 21st century, dental caries is still a dental

health problem in most industrialized countries, affecting 60-90% of pupils and most adults

1.2.7.2 In Vietnam

The rate of dental caries in our country is still high and tends to increase

1.2.8 Management and prevention of dental caries

1.2.8.1 Management of dental caries: Controlling the risk of dental

caries is essential

1.2.8.2 Intervention measures: In 1984, WHO introduced measures to

prevent dental caries with flour, fissure sealant, diet, oral hygiene, use of antimicrobial substances

1.3 The role of fluorideoral rinsing solution in prevention of early stage dental caries in permanent teeth of children

1.3.1 Mechanism of flour oral rinsing solution:

- Strengthen tooth enamel, resist demineralization and increase mineralization

- Resist the erosion of enamel

1.3.2 Studies on fluorideoral rinsing solution

- Foreign reseacrh: the research has demonstrated and clarified the mechanism of caries prevention of fluorideoral rinsing solution, effectively reducing the rate of dental caries There are still some limitations for example; the best time to use oral rinsing solution and a safe, simple, effective method has not yet been provided Therefore, more research is needed to clarify this issue

- Domestic research: 0.2% fluoride oral rinsing solution effective for preventing dental caries in children

1.4.Some key points of population and socio-economic situation in Phu Tho province

1.4.1 Socio-economic characteristics and health care condition: Phu

Tho is a Northern midland and mountainous province, with poor medical facilities and bad infrastructure

1.4.2 Status of school dentistry programm in Phu Tho

Almost schoold in the province have not adopted a school dental healthcare programme

CHAPTER 2 SUBJECTS AND METHOD OF RESEARCH 2.1 The cross sectional research

2.1.1 Location and time

- Time: from 08/2015 to 12/2015

- Location: Dinh Tien Hoang primary school and Tan Dan primary school, Viet Tri city, Phu Tho Province; 108 Institute of Clinical Medical and Pharmaceutical Sciences

2.1.2 Subjects of research

-Inclusion criteria: Pupils in the age of 7-8 years old (grade 2th) are

researching at Dinh Tien Hoang and Tan Dan primary school (Viet Tri city, PhuTho province) in 2015-2016, voluntarily participate and are allowed by parents

-Exclusion criteria:Pupils who are not in the age of 7-8 years old;

having orthodontic treatment with fixed braces; having primary dentition, systemic diseases or acute oral diseases; not volutarily participate and not allowed by parents

2.1.3 Methods of research

* Research design: Cross Sectional Descriptive Research

* Sample size:

Sample size is calculated with the following formula:

- Where: n: sample size; Z(1-α/2):realibility coefficient, kept in 95%;p: rate of incipient permanent dental caries rate of 7-8 years-old pupils (p = 78.8%) (research of Vu Manh Tuan 2013); q: estimated rate of non-incipient caries in permanent teeth of 7-8 years old pupils (q = 21.2%); d: absolute precision (d = 5%); DE: design coefficient = 1.2

- Sample size calculated according to the formula is 308 In fact, the research was conducted on 444 pupils

*Method for sample selection

- Step 1: Choose Dinh Tien Hoang and Tan Dan primary school

- Step 2: Interview and select pupils with the student's and family's consent

2.1.4 Processing

2.1.4.1 Data collection techniques

- Training and standardize researchers on examination and using

fluorescent laser Diagnodent lights

- Collecting data by using a questionnaire table and dental record

2.1.4.2 Procedures for clinical examination

- Step 1: Instruct pupils to keep oral hygiene with tooth brush, P/S toothpaste before examination

- Step 2: Exam and detect dental caries by observation method according to the criteria of ICDAS

DE d

pq Z

n = (21−/2) 2

-Step3: Exam, detect dental caries and demineralization by Dianodent 2190 device

2.2 The Intervention research

2.2.1 Location and time

- Time: from 01/2016 to 12/2018

-Location: Dinh Tien Hoang and Tan Dan primary school (Viet Tri city, Phu Tho Province); Institute of Clinical Medical and Pharmaceutical Sciences 108

2.2.2 Subjects

-Inclusion criteria: Pupils randomly chosenfrom the results of the

cross-sectional research must be required: having permanent teeth, voluntarily participating (with approval papers from parents or guardians)

- Exclusion criteria:Pupils that having primary dentition; receiving

topical fluouride treatment or already finished under 6 months; having fluoride allergic history; taking medicine which cross-react with Fluor such as Chlorhexidine are not chosen

2.2.2 Research methods:

-Research design: Randomized controlled clinical intervention research -Research sample:

We based on the formula of sample size calculation

Where: n1=sample size for the intervention group (use 0.05% fluorideoral rinsing solution), n2=sample size for control group (used 0.05% fluorideP/S toothpaste for children);Z(1–α/2)= the reliability coefficient, kept in 95% (=1.96);Z1-β=power (= 80%);p1= the rate of incipient caries

in intervention group after 18 months follow up is estimated 40%; p2 = the rate of incipient caries in the control group after 18 months follow up

is estimated 55%; p = (p1 + p2)/2

According to the formula, the minimum required sample size for both of research groups is n1 = n2 = 168 pupils However, to maintain research ethics, we selected all children in grade 2th who are eligible for the research To avoid psychology confusing for the pupils during the research, we chose all 2thgrade pupils of one school for the intervention group, and2thgradepupils of another school for the control group (intervention group: n=197, the control group n=247) After the examination, the sample size of both group (the intervention group

n=195 and the control group n=247) are larger than the minimum sample size needed (n=168) Therefore, the sample size in the research is

satisfied scientifically

2.2.3.Research progress

2.2.3.1 Procedure of intervention technique:

The control group: Brushing once a day in the morning in 4 minutes, the schedule is maintained for 18 months

The interference group: Rinsing with fluorideoral rinsing solution once a day in the morning in 2 minutes, the schedule is maintains for 18 months Both schedule are fixed

2.2.3.2 Indexes in intervention research

DMFT, DMFS index, efficiency index (EI), intervention index (InI)

2.3 Evaluation criteria in cross-sectional and intervence studies

2.3.1 Standards in evaluating dental caries

Using the standard of International clinical evaluation and detection system ICDAS, combining with fluorescent laser Diagnodent pen 2190

to support the diagnosis, classification and recording of mineralization level in enamel and dentin

2.3.2 Results

D0: non caries; D1, D2, D3: caries; D1, D2 incipient caries; D3: advanced stage caries

2.4 Processing and analysis:Data were input by EPI DATA 3.1 software,

analyzed by SPSS 20.0 software with medical statistical method

2.5 Errors in research: Measures are applied to limit errors from sample selection, measurement, recall bias to data processing

2.6 Ethnicity in research:All the pupils participating in the research

were explained and allowed by their parrents and their school Examination processing, sterilization is guaranteed No other tests were conducted during the research Free treatment will be given in any

student if their carious lesions get worse

Chapter 3 RESEARCH FINDINGS 3.1 Status of incipient caries in permanent teeth and some related elements in junior pupils 7-8 years-old

3.1.1 Characteristics of the research objects: Among 444 pupils

researched, the female rate accounts for 50.2%, higher than that of the male, 49.8% Particularly, in Dinh Tien Hoang Junior School the male rate, 51.8%, is higher than the female rate, 48.2%, while in Tan Dan Junior School the status is opposite with the female, 52.8%, higher than

the male, 47.2% But the difference between the rates of male and female presents no statistically significance with p>0.05

3.1.2 Permanent dental caries status

3.1.2.1 Permanent dental caries rates

χ 2 test: p1<0.01; p2>0.05; p3<0.001

Chart 3.5 Pupil permanent dental caries rates by schools (n=444)

Averagely, permanent dental caries rate of the two junior schools

is 57.9%, in which early decay rate (D1, D2) is very high and accounts for the majority (56.1%), the rate of late tooth decay (D3) low percentage (8.3%)

Table 3.4 Lesiond-level incipient caries rate by schools

carious stage D1 104 42.1 87 44.2 191 43.0 >0.05 Incipient

carious stage D2 54 21.9 73 37.1 127 28.6 <0.001 Lately carious

p (χ 2 test) <0.01 <0.01 <0.01

Lately permanent dental caries D3 (with cavities formed clinically) accounts for 8.3%, and increases up to 28.6% for lesions level D2 (color changing in wetted teeth and laser index >20) Dental caries rate takes the strongest rise in incipient carious lesion D1 (43.0% - color changing

after drying 5 second and laser index > 13) Difference of lesion-level dental caries rate presents a statistically significance with p<0.01

Table 3.6 Diagnosis-threshold permanent dental caries rate of detected

Rate

Rate (%) From D1 – D3 124 50.2 133 67.5 257 57.9 <0.001 From D2 – D3 60 2.3 79 40.1 139 31.3 <0.001

Permanent dental caries rate when the lesions form cavities clinically (from D3) accounts for 8.3%, and increases to 31.3% if the carious lesions are treated from D2 level (Color changing of wetted teeth and laser index >20) Dental caries rate takes the highest number when the incipient caries D1 (teeth

is changed in color after 5 second of drying and laser index >13) is included Difference of dental caries rate by diagnosis thresholds of D1 and D2 present

a statistically significance with p<0.001

3.1.2.2 DMFT and DMFS indexes

Table 3.7 DMFT index by schools

Dinh Tien

Hoang 1.2±1.7 0.5±1.2 0.1±0.5 1.8±2.2 0.0 0.02±0.3 1.8±2.2 Tan Dan 1.2±1.8 0.9±1.4 0.2±0.6 2.3±2.2 0.0 0.02±0.3 2.3±2.2

General 1.2±1.8 0.7±1.3 0.2±0.6 2.0±2.2 0.0 0.02±0.3 2.1±2.2

p >0.05 <0.001 >0.05 <0.01 - >0.05 <0.01

(p: Mann-whitney test)

DMFT index of the research object is 2.1±2.2, in which the index

of Tan Dan junior school’s pupils (2.3±2.2) is higher than that of Dinh Tien Hoang school (1.8±2.2), presenting a statistically significant difference with p<0.01 DT parameter (average of decayed teeth 2.0±2.2) takes the main part of DMFT index, in which D1T parameter (Dental caries D1 1.2±1.8) is the highest one Average of decayed teeth of Tan Dan school’s pupils (2.3±2.2) is higher than that of Dinh Tien Hoang school’s pupils with a statistically significant difference of p<0.001

Table 3.9 DMFS index by schools

Dinh Tien

Hoang 1.2±1.8 0.6±1.3 0.2±0.6 1.9±2.4 0.0 0.02±0.3 1.9±2.5 Tan Dan 1.5±2.6 1.0±1.6 0.2±0.7 2.7±2.9 0.0 0.02±0.3 2.7±2.9 General 1.4±2.2 0.8±1.5 0.2±0.6 2.3±2.7 0.0 0.02±0.3 2.3±2.7

p >0.05 <0.001 >0.05 <0.01 - >0.05 <0.01

(p: Mann-whitney test)

DMFS index of the research object is 2.3±2.7, in which the index

of Tan Dan junior school’s pupils (2.7±2.9) is higher than that of Dinh Tien Hoang school’s pupils (1.9±2.5) The difference of DMFS indexesbetween the two schools makes a statistically significance with p<0.01 DS parameter (average of decayed surfaces 2.3±2.7) takes the main part of DMFS index, in which D1S parameter (decayed tooth surface D1: 1.4±2.2) is the highest one Average of decayed tooth surface number

of Tan Dan school’s pupils (2.7±2.9) is higher than that of Dinh Tien Hoang school’s pupils 1.9±2.4 with a statistically significant difference of p<0.01

3.1.2.3 Some dental caries related elements

Table 3.14 Some elements relating to dental caries status and incipient

caries through multivariate regression analysis

Indicatings Dental caries Incipient caries

brushing with fluoride toothpaste at least twice a day, are closely related

to dental caries and incipient caries status, among which the element of teeth with deep fissures is the strongest factor (increasing dental caries risk 4.54 times and incipient caries risk 4.45 times) The dental caries risk is reduced 0.37 times, and incipient caries 0.34, in the pupils brushing with fluoride toothpaste at least twice a day

3.2 Fluoride (NaF 0.05%) oral rinsing solution for incipient permanent dental caries

3.2.1 Dental caries rate changing

Table 3.17 Incipient caries rate D1, D2 changingof the two groups by time

Incipient caries rate D1, D2

p (prtest test)

intervention

Pre-n (%)

After 6 months

n (%)

After 12 months

n (%)

After 18 months

37 (40.7)

32 (35.2)

p12 > 0.05

p13<0.001 p13<0.001

Female

(n=104) 64(61.5)

75 (72.1)

46 (44.2)

44 (42.3)

p12 > 0.05

p13 < 0.01 p14 < 0.01

Total 128 (65.0) 140

(71.1)

83 (42.6)

76 (39.0)

p12 > 0.05

p13<0.001 p14<0.001

74 (57.8)

83 (64.8)

89 (69.5)

p12 < 0.05 p13 < 0.01 p14>0.001

Female

(n=119)

62 (52.1)

85 (71.4)

94 (79.0)

86 (72.3)

p12 < 0.01 p13<0.001 p14<0.001

Total 121

(49.0)

159 (64.4)

177 (71.7)

175 (70.9) p < 0.001

p<0.001

p1<0.001 p2<0.001 p3<0.001

In the control group, incipient caries rate (with lesion levels D1 and D2) increases from 49.0% pre-intervention up to 64.4% after 6