1
THESIS INTRODUCTION
ACKNOWLEDGEMENT
Discoloration of teeth occupied a high percentage (86.90%) in the
community, including tetracycline stained teeth was 22.86% and this
percentage was mainly found in middle age. Sign of tetracycline stained
teeth is serious changes of teeth color in which, normal teeth change into
yellow-brown or green or dark grey colors, this obviously influences to
aesthetics and causes less confidence in the life.
To treat to a tetracycline stained denture, there are many methods
such as composite fillings, porcelain veneers, full-coverage crowns. These
treatments require the patients suffering intervened dental operations
which cause loss of hard tissue of teeth, time-consuming, costly and this
acquires to be replaced periodically. A protocol of less invasive for hard
tissue but changing color of teeth is by whitening discolored teeth with the
help of cold light activation.
Currently in Viet Nam, further study projects, comprehensive
clinical, safe bleaching protocol on the morphological structure of the
enamel surface and evaluation the effectiveness of the in-office bleaching
treatment tetracycline stained teeth with the help of light activation;
especially cold light source is still very limited. Therefore, we conducted a
thesis: “Research effectiveness of vital bleaching treatment for
tetracycline stained teeth” with the aims:
1. Describle clinical characteristics of tetracycline stained teeth at
degree I and degree II on patients who were treated by vital
bleaching method.
2. Assess effectiveness of vital bleaching method for tetracycline
stained teeth.
3. Evaluate structural changes of enamel surface morphology
under the scanning electron microscopy on tetracycline stained
teeth after experimental bleaching.

THESIS STRUCTURE
Thesis consists 146 pages, apart from the acknowledgement,
conclusion, and proposal consist 5 pages, the thesis consists of 4 chapters:
Chapter 1: General study issue (including 34 pages), Chapter 2: Research
objectives and methodologies (including 30 pages), Chapter 3: Research
results, (including 37 pages), Chapter 4: Discussion, (including 40 pages).
The thesis comprises 40 tables, 28 charts, 40 photos, 156 references (16 of
which were in Vietnamese, and other 140 were in English).
B. THESIS CONTENTS
Chapter 1. OVERVIEW
1.1. Histological structure of tooth enamel definition.
1.1.1. Histological structure of tooth enamel
2
2
3
Organic forms: Mature enamel consists mainly soluble and insoluble
proteins and a small amount of fat and carbohydrates. Teeth staining are
pigments combined with fatty acids, proteins, enzymes, on the enamel
surface, it contains long chain links, alternating single link chains and
double link chains. Bleaching has used hydrogen peroxide (H
2
O
2
) to
remove proteins. Observation under scanning electron microscopy (SEM),
H
2
O
2
decomposes into free radicals causing oxidation of fatty acids and

4
fluorescence trips under ultraviolet light. Tetracycline stained teeth were
divided into 4 degrees.
1.3. Effectiveness of vital bleaching.
1.3.1. Whitening agent.
1.3.1.3. Mechanism of whitening agent: In bleaching process, H
2
O
2
is a
final product. H
2
O
2
diffuses through the organic matrix of the enamel,
dentin and decomposing into free radicals (HO
2
*, HO*, O*) with single
electrons, they have enormous energy and instability and they will
combine with organic molecules to achieve stability. So pigments can be
broken from large molecules into small molecules and they could be
removed easily by diffusion of substances into simpler molecules that
reflect less light therefore they obtain bleaching effectiveness.
1.3.2. Vital bleaching methods
1.3.3. Studies of vital bleaching results in the world and in Vietnam
1.3.3.1. In the world: Summary of clinical studies and in vitro experiments
has shown that: Safety and efficacy of general bleaching teeth and
particular tetracycline stained teeth focuses on at-home bleaching
techniques. Several case reports in-office tetracycline stained teeth
bleaching gave good results at the end of treatment period, but time

2.1.2. Research location & time
Research location: Institute of Odonto - Stomatology under Ha Noi
Medical University, National hospital of Odonto - Stomatology. Dental of
108 Military Central hospital.
Time: From 01/ 2010 to 01/ 2013.
2.1.3. Research methodologies
2.1.3.1. Research design
Intervention of uncontrolled clinical trials, the following before - after
comparison time series at 8 times.
2.1.3.2. Research sample
Using formula for comparison of 2 rates. p
1
value is the proportion of
patients with good results at the begin of treatment (p
1
= 0 for all patients
in a state that not color well), prognosis for rate change after each
intervention was 20% of patient will improve your teeth situation (p
2
=
0,2), the intervention is 3 times.

z
(1- α/2)
: The trusted coefficient at probability rate 95% (= 1,96).
1-β

: Sample force (= 90%)
5
5

sensitive Pro - Relief) 4 weeks.
2.1.5. Assessing the effectiveness of treatment
2.1.5.1. Evaluation of color change
The indicators change color in the Munsell color spectrum and CIELa*b*
color space: ∆C, ∆h, ∆V, ∆b*, ∆L, ∆a*, ∆E. According to American
Dental Association, the gold standard for assessing the effectiveness of
whitening products is ∆E ≥ 4.
2.1.5.2. Assessing the result of treatment
Based on these criteria: Color change according to Vita and the side effects
of the bleaching products (sensitive, mucosal and gingival lesions) and
level of satisfaction of patients, this study divided the good, rather and
6
6
7
average results. Each patient has a follow-up vote bleaching protocol and
recorded after each follow - up visit.
2.1.6. Research variables: The independent variable is the individual
characteristics of the patient. Dependent variable: Munsell color spectrum
(V, C, h) and CIELa*b* color space (L, a*, b*) in the first votes. The color
change in the Munsell color spectrum and CIELa*b* color space ∆C, ∆h,
∆V, ∆L, ∆a*, ∆b* và ∆E in the nexts. 7 evaluations. Evaluation treatment
outcome: Good, rather, average.
2.1.7. Patient observation, management & study data collection
Data collection through 8 evaluations: Before treatment, treatment 1
st
, 2
nd
,
3
rd

O
2
, and immersion
in artificial saliva. Group 2: Bleaching with 35% H
2
O
2
, immersion in
artificial saliva, brushing your teeth with SensodyneFresh Mint toothpaste
daily. Group 3: Bleaching with 35% H
2
O
2
, immersion in artificial saliva,
brushing your teeth with SensodyneFresh Mint toothpaste daily and
bleaching finish brushing your teeth with Colgate sensitive Preo –Relief 2
weeks.
Research on SEM: After an experiment done, teeth samples were fixed in
aluminum column for SEM evaluations and then dehydrated, dried in the
environment at 37ºC (room temperature) in a closed tank with silica gel for
about 12 hours, samples then were fixed into a base and covered with gold
(deskII, Dentor Moorestown, NJ, United States) for 80 seconds and
examined under SEM (JEOL, Tokyo, Japan) with voltage 15 KV.
Analysis of the results, comparison between the bleached enamel and
control group in the magnification x750, x1500, x2000.
2.2.5. Assessing the result
According to Le Van Son et al (2011) change in the enamel surface
following lesion degree into 4 types: No lesion (degree 0): No change in
the enamel surface in the control group. Mild lesion (degree 1):
Dominantly, enamel surface morphology changed slightly, alternating as

Chapter 3. RESEARCH OUTCOMES
3.1. Clinical characteristics of degree I and II tetracycline stained
teeth
3.1.1. General characteristics of study subjects
Total of 78 patients were studied: Percentage of female patients (78.2%)
was higher than male patients (21.8%). A group of age 20 - 29 (20.5%)
was lower than a group of age 30 - 45 (79.5%). The rate of degree II
tetracycline stained teeth in a group of age 30 - 45 was 97.4%. Degree II
tetracycline stained teeth was mainly in a group of age 20 - 29 (15/16
cases).
3.1.2. Clinical characteristics degree I and II tetracycline stained teeth
Table 3.5. Distribution of colors in the Munsell (C, h, V) color
spectrum according to dental groups
Dental group n
V C h
± SD ± SD ± SD
Incisor 78 13,2 ± 1,8 27,8 ± 4,3 79,4 ± 4,9
Canine 78 15,5 ± 0,5 31,6 ± 5,8 75,9 ± 4,2
Premolar 78 12,1 ± 1,7 23,8 ± 3,7 81,7 ± 2,9
p (ANOVA test) < 0,01 < 0,01 < 0,01
General 78 13,6±1,2 27,7±4,3 80,0±3,8
Vita V, Chroma C: Canines were highest and premolares were lowest,
there was statistical significant (p<0,01). Hue h: Canine were lowest and
premolar were highest, there was statistical significant (p<0,01).
Table 3.6. Distribution of colors in the CIELa*b* color space
according to dental groups
Dental group n
L a* b*
± SD ± SD ± SD
Incisor 78 71,0 ± 4,2 5,0 ± 1,9 27,3 ± 4,4

4,1±0,
4
26,8±1,
0
27,1±1,
0
81,4±0,
9
12,4±0,
2
Degree II
3
9
66,3±3,
9
6,2±1,
0
27,4±6,
2
28,4±5,
9
76,6±4,
0
14,8±0,
5
p(Mann-Whitney
test)
< 0,05 <0,05 >0,05 >0,05 <0,05 <0,05
L, h: Degree II was always lower than degree I, there was statistical
significant

: There was significant reduction (average reduction 12.1 units).
Next times: Average value was relatively stable.
Table 3.12. The change of Vita V (∆V)
Dental
group
n =78
Before
treatment
1
st
2
nd
3
rd
3
weeks
3
months
6
months
12
month
s
p(A
NO
VA
test)
± SD

±SD

0,01
Canine
0,0
-
2,2±1,
6
-
6,7±2,
1
-
11,3±2,
1
-
11,3±2
,1
-
10,5±2
,1
-
10,1±2,
1
-
9,7±2,2
<
0,01
Premola
r 0,0
-
1,9±1,
8

<
0,01
General for all research subjects and for all 3 groups of teeth (incisors,
canines, premolars): V reduced over time intervention and follow-up, there
was statistical significant (p < 0,01). Over 12 months of follow-up, general
V index was average reduction of 8.9 units, incisors were average
reduction 10.1 units, canines were average reduction 9.7 units, premolars
were average reduction 6.8 units. Average value of V at evaluation of 8
times: from 1
st
to 4
th
: There was significant reduction (average reduction
10.1 units). Next times: Average value was relatively stable.
The change of hue (∆h): General for all research subjects and for all 3
groups of teeth (incisors, canines, premolars): h increased over time
intervention and follow-up, there was statistical significant (p < 0,01).
Over 12 months of follow-up, general h index was average increase of 8.4
units, incisors were average increase of 9.4 units, canines were average
increase of 10.7 units, premolars were average increase of 5.3 units, there
was statistical significant (p < 0,01). Average value of h at evaluation of 8
13
13
14
times: From 1
st
to 4
th
: There was significant increase (average reduction
10.2 units). Next times: Average value was relatively stable.

: There was significant
increase (average increase 8.7 units). Next times: Average value was
relatively stable.
The change of yellowness (∆b*): For all 3 groups of teeth (incisors,
canines, premolars): b* reduced over time intervention and follow - up,
there was statistical significant (p < 0,01). Over 12 months of follow - up,
general b* index was average reduction of 10.7 units, incisors were
average reduction of 12.1 units, canines are average reduction of 13.4
units, premolars were average reduction of 6.5 units, there was statistical
significant (p < 0,01). Average value of b* at evaluation of 8 times: from
1
st
to 4
th
: There was significant reduction (average reduction of 11.5 units).
Next times: Average value was relatively stable.
The change of redness (∆a*): For all 3 groups of teeth (incisors, canines,
premolars): a* reduced over time intervention and follow - up, there was
statistical significant (p < 0,01). Over 12 months of follow - up, general a*
index was average reduction of 4.4 units, incisors were average reduction
of 4.8 units, canines were average reduction of 6.1 units, premolars were
average reduction of 2.4 units, there was statistical significant (p < 0,01).
Average value of a* at evaluation of 8 times: From 1
st
to 4
th
: There was
14
14
15

rd
3
weeks
3
mont
hs
6
mont
hs
12
months
p(AN
OVA
test)

±
SD

± SD

± SD

±
SD

± SD

± SD

±

canines, premolars): ∆E increased over time intervention and follow - up,
there was statistical significant (p < 0,01). Over 12 months of follow - up,
general ∆E was average increase of 14.7 units, incisors were average
increase of 15.6 units, canines were average increase of 19.7 units,
premolars were average increase of 8.9 units, there was statistical
significant (p < 0,01). Average value of ∆E at evaluation of 8 times: From
1
st
to 4
th
: There was significant increase (average increase of 16.1 units).
Next times: Average value was relatively stable, 100% achieve to efficacy
color change, efficacy of bleaching teeth.
3.2.2. Evaluation of treatment result
3.2.2.1. Results 1 time treatment: After 1
st
treatment only achieve rather
and average results, in which rather result was 44,9%, an average result
15
15
16
was 55.1%. Degree I tetracycline stain: rather result was 71.8%. This
result was higher than degree II (17.1%). The rather result of female was
50.8%, this result was higher than male (23.5%). The rather result of group
of age 20 - 29 was 87.5%. This result was higher than group of age 30 - 45
(85.9%).
3.2.2.2. Results of 2nd time treatment: After 2
nd
treatment: Good result was
85.9%, rather result was 12.8%, and average result was 1.3%. Degree I

3
Total
p
(testχ
2
)
n % n % n % n % n %
Group 1
2 6,5 17 54,
8
9 29,
0
3 9,7 31 100,
0
<0,05
Group 2
4 12,
9
18 58,
1
7 22,
6
2 6,4 31 100,
0
Group 3
11 33,
3
19 57,
6
2 6,1 1 3,0 33 100,

90,9%, followed by group 1 and group 2 with 61,3% and 71%,
respectively the difference is statistically significant, p < 0,05.
Comments featured several photos of each research group
Control sample: There were Tomes pits on the enamel surface with
scratches.
Group 1: A part of the enamel surface bleached (magnification x1500), the
image: Papillary enamels were formed after bleaching. Papillary enamels
had mineralization seeds. There was a conjunction between papillary
enamels.
Group 2: The enamel surface was evident Tome concave but sharp blunt,
there were irregular spherical particles.
Group 3: Enamel surface morphology was similar to its of the control
sample but Tome holes were shallower, not clear with smooth and shiny
surface (magnificantion x750).
CHAPTER 4: DISCUSSION
4.1. Clinical significance of I, II degree tetracycline discolored teeth
4.1.1. General characteristics of the study objects
Research on 78 patients, among them the female patients were four
times higher than that of the male patients. Probably due to the aesthetic
needs of women, this result was similar to the study by Pham Thi Thu
17
17
18
Hien (2012), Nguyen Thi Phong Lan (2004). According to Phan Le Thu
Hang (2004), the female patients with tetracycline stained teeth was 1.5
times higher than that of male patients. Thus the results of this study fitted
completely.
Percentage of patients in the group of age 30 - 45 were 4 times as
many as the group of age 20 - 29. Tetrcycline stained teeth rate of type II
in the group of age 30 - 45 accounted for the highest percentage of 97.4%.

19
tooth tissue. Darker dentin enamel discoloration. Light tetracycline
oxidized quinone create red. Group teeth before exposure to light easily
and easily change colors than the group that later.
Distribution of tetracycline discolored teeth in the CIELa*b* color
space: L average brightness of the canines were the lowest and of the
premolars were the highest, with statistical significance. Redness a*,
yellowness b*, average of the canine were highest and of the premolars
were lowest, with statistical significance. This result was similar to
findings of Kwon (2012) and Venkateswarlu M et al (2009), Kugel (2002).
In this study yellowness b* were higher than the average of yellowness in
Kwon’s (2012) study conducted in Japan and Kugel made in the U.S. in
2002. This difference was probably due to different races. Thus, when the
dentists whiten the teeth they need to be regardful of these parameters. To
have beautiful white teeth for patients with tetracycline teeth the dentist
should be noted when applied to teeth bleaching time for each tooth to
bring the best whitening results after bleaching to achieve similar
parameters.
Distribution colors in the Munsell color spectrum and color space
based on the degree of tetracycline stain: Degree I tetracycline teeth
have the lighter color and higher hue than degree II. Degree I have redness
lower than degree II, the difference was statistically significant. Also, the
yellowness and the chroma was no difference. The colors Vita V: Degree I
tetracycine stained teeth: yellow - gray - light brown level. Degree II
tetracycline stained teeth: yellow - gray - darker sepia level, the difference
was statistical significant. Chroma of degree I tetracycline stained teeth
(81.4) correspond to orange, tetracycline teeth degree II (76.6) correspond
to red gray yellow. This result was similar to that of Jordan and Boksman
study (1984), but not to the specific parameters for each chromosome
level, while this study gave specific indicators for each level of

average reduction of 8.9 common units, incisor of average reduction was
10.1 units, canine of reduction average was 9.7 units, premolar of
reduction average was 6.8 units. Case report of Kinoshita et al (2009) for
the laser teeth whitening for cases tetracycline stained teeth which color
change from C4 to B2 corresponding change compared to 12 units for the
first time, according to Tavares et al (2003), improved color compared to
13 units for the first time. While this study was to perform 3 new
bleaching treatment achieved an average change of 10 color units. The
results of many studies on vital bleaching tetracycline stain also vary
considerably, according to Matis et al (2006) bleaching method used in the
last 6 months to be able to achieve the color change from C4 to B1 15
color units, respectively. According to Nguyen Thi Phong Lan (2004) after
bleaching improves average 9 - 10 units tetracycline stained teeth to bring
20
20
21
new satisfaction for dentists and patients. In this study, 2
nd
post-treatment
colors mean reduction of 6.5 units should continue 3
rd
therapy and results
were expected by dentists and patients. According to Bowler et al (1997)
that the reason chromosomal tetracycline to treat prolonged or repeated
treatment at the clinic was able to generate by tetracycline with calcium
ions and chelating into cartilage, teeth and bones to form a tetracycline
complex - especially calcium orthophos-phate on dentin. Because of the
deposition of pigment in the deep dentin should take time and multiple
treatments to achieve desired results.
4.2.1.2. Evaluation of color change according to the CIELa *b * color

2
O
2
and diffuse through the
enamel to the dentin, reacts with organic pigments was the key factor to
form the tooth color. According to Lee et al (2009) Bleaching by light
plasma was improved significantly. In - office bleaching using 35% H
2
O
2
concentrations and sources different light. Lighting accelerates
decomposition of H
2
O
2
generated free radicals OH* (double after
phototherapy for 1 minute) molecules react with surrounding color as their
structure was broken and whitening takes place. This result was a
testament to the rapid changes seen when using whitening lamp.
Results of treatment of stable only after 12 months of research similar to
Matis et al (2002) and Leonardo et al (2003). This result may be achieved
by chromosomal tetracycline was endogenous chromosomes of infected
ivory, less affected external environmental factors. End bleaching
treatment process we have implemented a data mining process for patients
brush your teeth by Colgate Sensitive Pro-Relief toothpaste enamel surface
should be shiny and smooth over, contributing to maintain the treatment
effect after whitening.
4.2.1.3. Evaluation of color change in ΔE
For all three groups of teeth (incisors, canines and premolars) ΔE increases
over the duration of treatment and follow-up with statistical significance.

optimal results by Kinoshita et al (2009) in Japan, he used the laser teeth
whitening treatment using 35% H
2
O
2
was once an appointment can
improve color from C4 to B2. According to Lee's (2009) plasma whitening
lamp color change ΔE 19.7 overall. This was only sporadic studies, not
only evaluate the system and at the end of treatment, so this study
conducted in 8 track time in the 12 - month evaluation in a systematic
manner and has brought efficient in the short term for patients with
tetracycline stain. Short duration of treatment for optimal results, patients
can expect a maximum change at week 2 after treatment 3 times with 16.1
ΔE units achieved similar results bleaching treatment teeth at home for 6
months. The results of this treatment can be the basis for advising patients
infected with tetracycline teeth of time can change color to achieve desired
performance after 2 weeks and 3 waves at the clinic. This result can help
dentists build bracket appropriate treatment for patients with planned
arrangements and time to comply with treatment.
According to Haywood (1997) at - home bleaching method was the
difficulty: Treatment depends entirely on the patient, dentist can not force
patients to comply with treatment, with treatment lasting several weeks or
months. The process of bleaching treatment was difficult that was sensitive
dentin. Results of treatment depends on the cooperation and compliance of
patient treatment. In fact, there were many difficulties for patients required
to comply with the bleaching process, especially for patients with tight
timescale. So at the clinic bleaching meet anticipated demand for both
patients and aesthetically time.
23
23

rd
times treatment: Results of the general good research
subjects was 96.1%, 3.9% was pretty. Tetracycline stained teeth type I
have good results (94.9%) lower than tetracycline stained teeth type II
(97.4%). Female achieve better results than men. Group of age 30 - 45 less
fruitful group of age 20 - 29. This study follows three treatments reduced
the average Vita 10.1 colors. This result was similar to the results of
Nguyen Thi Phong Lan (2004). A very satisfied (96.2%) after the 3
rd
times
treatment so this study obtained a result quite ideal (well 96.1%). After
two treatments were created to facilitate the path to drug dentin impact
24
24
25
should ease in treatment the 3
rd
times to achieve outstanding results. With
three times the whitening treatment was a powerful influence on the color
molecule so infected the tetracycline stained type II significant color
change than type I.
According to Chandrasekhar et al (2011) using cold light source, 35%
H
2
O
2
system agents and Beyond light after a treatment has improved from
D3 to A1, A3 to B1 from level 9 to change the Vita. According to
Kinoshita et al (2009), using 35% H
2

25
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