nghiên cứu phục hình hàm khung cho bệnh nhân khuyết hổng xương hàm dưới bản tóm tắt tiếng anh

A. Introduction
Rationale
According to the statistics at maxillofacial surgery departments,
each year, there is a considerable number of patients with defect of the
maxillary and mandible. The common reasons underlie the consequence
after surgery of benign or malignant diseases of jaw bones. The number
of patients with demand of prosthesis mandible which suffers from
bone defect can account for 10-15% of total patients with maxillofacial
prosthesis.
After the patients have been formed the mandible defect, the
functions of jaw bone must be recovered by the prosthesis.
The types of removable prosthesis include frame work, plastics
frame and prosthesis supported by implant. Plastic flame is
uncomfortable, the masticatory force is weak. Prosthesis supported by
implant has the good masticatory force but it required sufficient of
amount and quality of bone tissues and attached gingival. Flame work
does not require much condition but the results of rehabilitation process
for masticatory, pronunciation and aesthetical functions are quite good.
All over the world, the frame work rehabilitation for patients
suffering from mandibular defects with bone graft has been mentioned
by many authors for a long time. In Vietnam, there is no such deep
research about this topic. Therefore, for the purpose of improving the
quality of treatment for these patients, we decided to study the subject
of thesis: “RESEARCH ON REHABILITATION FRAME FOR
PATIENTS WHOSE TEETH LOST WITH DEFECTS OF THE
MANDIBLE ” with two main purposes:
1. Describe the clinical characteristics and x-ray features
of patients who have mandibular defects with bone graft or
bone basement.
2. Review the effectiveness of functional and esthetic
rehabilitation when treating with flame work for losing teeth

of these patients.
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Importance of thesis topic
Mandible is considered as the supported-frame for complex
functions of mouth, throat and facial shape. Therefore, mandibular
defects negatively effects the eating, pronouncing and aesthetic
functions. Psychologically, the patients may retreat from social
activities. The large defects can be called disabilities.
After the patients have been reformed the defects, the function
rehabilitation process is required to help them to gain the work and
socialization capacity.
NEW CONTRIBUTIONS
1. The clinical characteristics and x-ray features of patient
with mandibular defects has been carefully described in the thesis
to help the surgeon make improvement in the operation.
2. The result of prosthetic treatment for edentulous people from
mandibular defects after bone grafting was evaluated on the basis of
many indexs, criteria, tests and observations in a long period.
3. The role of soft plastic with the unset Sillicone to neutral zone and
add base in case of mobile saddle mucosa is confirmed for better stability
4. The techniques of functional anatomy are required for these
patients with various materials: Sillicone with soft plastic and the
compound of thermoplastics and soft plastics.
5. Application of MAI (Mixing Ability Index) in masticatory
function evaluation is proved to be highly reliable.
DISSERTATION STRUCTURE
Addition to introduction, conclusion, the thesis has 4 chapters:
Chapter 1: the overview of the study: 36 pages; Chapter 2: the objects
and research methodology: 26 pages; Chapter 3: Results: 38 pages;
Chapter 4: Recommendation: 38 pages. The apendix concludes of

graphs: 48, charts: 22, imagines: 25 and 127 referent documents
(English: 99 and Vietnamese:28)
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B. CONTENT
Chapter 1. OVERVIEW
1.1. Anatomy of mandibular bone
Mention to: External structure, internal structure, inferior
mandibular nerves the mandible, arteries feeding the mandible, the
dominant muscles affecting movement of the mandible.
1.2. Mandibular defects and rehabilitation methods
1.2.1. Reasons and consequences of mandibular defects
Reasons for mandibular defect: mainly to treat diseases after
surgery.
Consequences caused by mandibular defect: According to Peri và
Coll, the defects will cause “jaw – teeth – muscle imbalance", leading to
the distortion which will adversely affect the functional, aesthetic and
psychological impacts.
1.2.2. Classification of mandibular defect:
Classification by author: Julid Tam, Kadoda, Neal Garret and
Brian J.B
1.2.3. Rehabilitation of mandibular defect:
There are 2 main types:
- Using compounded material to rehabilitate the losing bones
using frame but no functionally retrievable ability.
- Using biomaterials made from bone to have bone grafting and skin
transplant if needed is the best method. The method with functional
rehabilitation is bone grafting with vascular
1.3. Flame work
- Aker (1918) is considered as the first proponent of seamless
methods: claps, connector and saddle, marking the birth of flame work.

- Advantages: Compared to partial removable dentures with
the plastic ground, flame work brings the better effect for
masticatory and pronouncing thanks to a casting over with the claps
and rests at the real teeth, the masticatory force is delivered to the
abutment và edentulous ridge.
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- Indications: unsuitably fixing bridge for large losing gaps, losing
teeth without limitation, vanishing edentulous ridge in the toothless area,
decreasing supports in around teeth area, prosthesis after surgery.
- Structure of the flame work: Major connector, manor connector,
claps, indirect retention which is the rest of incisors.
1.4. Removable denture prosthesis for patients having defects of the
mandible with bone rehabilitation or jaw bone base.
Removable conventional plastic: simple technique but the
masticatory force is worse than flame work, steadiness and retention is at
low level, large size and high mobility which all created the feeling of
unsteadiness for patients.
Indications: Patients with mandibular defects who lose all teeth or
have small amount of teeth left with mobile level II or higher.
Removable conventional frame work: be indicated when large
edentulous gaps by bone defects that cannot do the bridge or patients do
not have abutment left that far from the edentulous gap. Remaining
teeth with dental and periodental meet requirement to make
abutments.
Prosthesis supported by Implant: should follow all the basic
principles of normal procedure, notice the attached tissues is normally
inadequate after bone grafting so it calls for the epithelial
transplantation before putting implant or carry out at the same time of
putting implant.
1.5. The study of prosthesis for patients who have mandibular

defects
The view point of doctors at different time periods: Kelly (1965),
Kratochvil (1979), Henderson- Steffel (1981), Davis (1982) Kien
Thomas (1994), Shu - Hui Mon (2001), John Beumer (2002), (2007).
These authors have generalized and added new techniques to improve
the rehabilitating process.
In Vietnam, there is no deep study for this topic.
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CHAPTER 2
SUBJECTS AND METHODS
2.1. Study subjects
The subject for study is the patients with mandibular defects who
have been grafted autologous bone or remain mandibular bone base and
are assigned for frame work.
Selection criteria: The patients have been bone grafted after at least
6 months or satisfied these conditions: patients have 4 teeth left which:
hard tissues around teeth are unharmed or repaired, teeth with 1 root had
wobble level 1 or 2 or teeth with multiple roots had wobble level 1; on
Panorama X-ray: good grafted bone, no-suffered bone, the patients were
rehalibitated by denture but it can not be used or broken, suffered jaw, the
patients volunteer participating in the research.
Exclusion criteria: patients with bone grafting to rehabilitate
completely the mandibular, people did not cooperate in the study.
2.2. Place and time
- Place: School of Odonto Stomatology - National Hospital of
Odonto-Stomatology and Hanoi Medical University
- Time: From 6/2008 to 6/2013
2.3. Methodology
2.3.1. Design study
Open clinical trial study without references to evaluate the

effectiveness of the before – after model.
2.3.2. Model collection method
- Model collection: Random model ; all patients with mandible defect
satisfied all these conditions.
- Model size: Formula:
q
d.p
Zn
2
)2/1(
α−
=
Z: confidence level (95%), p: % with good or acceptable
masticatory ability: 65%, d: degree of freedom 17%
n = 31 actual test on 33 patients.
2.3.3. Data collection method
2.3.3.1. Research tools: clinical tools and labo.
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2.3.3.2. Examine, review the clinical characteristics, x-ray, model of
patients
- Making the survey for info
- Examine and evaluate the consequences after surgery, the
characteristics of teeth and soft tissues for prosthesis. The surveyor
makes the design of frame work.
2.3.3.3. Treatment
Procedure: Treatment before prosthesis, mouth check, make the
model, survey and design the frame work, mold frame at labo, trial
flame and take the function frame: simple separated parts or
combination of prosthesis space, determine the relationship of upper
and lower jaw and set up the artificial teeth by articulators and

articulators Quick master B2, trial teeth, complete the frame, fitting the
frame works and soft plastic cushion.
2.3.3.4. Evaluate the effectiveness of the treatment
a. After fitting the frame works: 3 main criteria: Retention,
occlusion and aesthetics. Based on factors and time of fixing the frame
after fitting the frameworks: to fix the occlusion.
b. Evaluation after 2 weeks: Evaluate the adjustment and
masticatory function.
c. Evaluation after 1 month: MAI, life quality evaluation
according to Albert
d. Evaluation after 6 months: Features of frameworks,
evaluate the effect of frameworks to abutment, periodental and oral
hygiene and identify using add rebase.
e. Evaluation after 1 years, 18 months, 2 years and over 2
years: similar to after 6months and added the comparison
2.4. Date processing: Data was treated with medical statistics; apply
the software Epi-Info version 6.0 and some logic mathematics methods
2.5. Ethnics in research: all the patients were explained about the
procedure of treatment. All volunteered to joint the study. The procedure of
treatment was ensured to follow the safety. The info collecte is treated with
secret and used with the research purpose to improve the life quality of
patients. The thesis proposal has been approved by the commitee. The actual
research is ensured to closely followed the thesis proposal.
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Chapter 3
Research Result
3.1. Clinical characteristics, x-ray of patients
3.1.1. General features of models: Majority is young patients under
34: 18 patients, equal to 54,5%. The youngest patient was 16, the
oldest was 65. About gender, 54,5% female patients. The main

reasons for mandibular defects is from the surgery to treat diseases:
93,9%. Patients who have vascular bone grafting mainly surgery in
1st stage: 30,3%, patients who have avascular bone grafting mainly
surgery in 2
nd
stage 42,4%. Dental hygiene status at low level were
54,5%. According to Kadoda, mandibular defects had 9,1% of
patients who still have bone base, 87,9% of patients who losed bone
pieces. There were 36,4% of patients with small and big losing
molars, 18,2% of patients with 2-side-losing maxillary teeth, canine
teeth and 1-side losing small and big molars.
3.1.2. Complications, functions and aesthetics features
Complications and function in post-surgery patients: 72,8% of
patients had trouble with talking loundly and fast; 12,1% found it hard
to pronounce s and tr sounds; 30,3% were difficult to open surgical
side; 60,6% losing or decreasing the sense at inferior mandibular
nerves; 81.8% sometimes biting their own tongue, check and lips when
chewing; 36,4% making the sounds at temporo-mandibular when doing
activities, 66,7% increasing movement amplitude of condyle. When
opening mouth, there were 75,8% of patients suffering deviating jaw
arch toward the operated side, 72,7% deviating to the other sides. 78,8%
with zic zag movement lines accordance with Posselt’s graph. 30,3%
have changed curve of Spee and of Wilson.
The relationship of mastication coefficient and mastication function
with the scale of 100 point of patients before wearing flame work.
There was 52,4% of patients with mastication coefficient
from 50 – 75, at the good level (70- 80 point); 75% with the
coefficient of under 50 at the acceptable level (50- 60 point).
Average of mastication fuction and mastication
coefficient: the average mastication function was 65.2 ±15.0;

mastication coefficient was 50.2 ± 14.1 on average.
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3.1.2.2. Facial form and facial aesthetics
Facial form: 60.6% having clearly flat faces, 24.2% having lower
lip corners at the surgical side.
Change of horizontal branches and jaw angle of patients with
bone rehabilitation: there were 36.4% of patients with asymmetrical
horizontal branches, 87.9% with clearly concave jaw angle.
MAI by observing the color waxing block before putting
frame: large number of patients got the good review: 81,8%; 12,1% at
low level.
3.1.3. Condition of edentulous ridge, teeth and structure of dental
surrounding
3.1.3.1. Conditions of edentulous ridge and frenums
Almost patients had the straight edentulous ridge and
asymmetrical with next jaw arch (87.9%); 75.8% with edentulous ridge
lower than mouth floor, 60.6% with scars on the top of edentulous ridge
and 63.6% had mucosa on the moving edentulous ridge. Majority of
patients had buccal frenum, labial frenum and lingular frenum on the
top of edentulous ridge with the rate of 45.5%; 18.2%; 24.2%
respectively while these percentages on the top of moving edentulous
ridge were 21.2%; 12.1% và 6.1%.
3.1.3.2. Dental and periodental
Condition of hard parts and surrounding structure of abutment
Popular issues were worn occlusal, occlusion margin with GI = 1
(n2) was 42.0%, n1: 17.9%.
Classify patients with loss of adhesion around the abutment and the
time for prosthesis after the surgery to graft bone: majority of abutment lost
adhesion < 3mm: after 2 - 5 years, n1 abutment: 8.8%; n2 abutment:
17.5% and after 5 years n1: 8.8%; n2: 11.3%; only 3 n1 abutment

(8.8%) lost adhesion equal 3 - 6mm.
Classify patients with shape of abutment’s root and alveolar
bone resorption X – ray: Patients with long and thin teeth roots at n1
abutment accounted for 57.1% (no alveolar bone resorption group),
33.3% (under 3 mm alveolar bone resorption group); for n2 abutment:
72.7% (no alveolar bone resorption group), 27.3% (under 3 mm
alveolar bone resorption group)
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Mobile level of abutments with ages: highest level in the age of 35-
65 happened with degree 1 at n2 abutment: 63.8%, at n1 abutment: 47%.
3.2. Effectiveness of functional and aesthetics rehabilitation of
frame works
3.2.1. Frame work prosthetic treatment
The procedure of making the frame for prosthesis by bone
grafting method: the method making the frame by Silicone and normal
trays was used for patients who had vascular bone grafting (87.5%).
Frame by Silicone and individual trays were used for avascular bone
grafting (56%). In 2
nd
time making frames, it was mainly partial +
prosthetic by Silicone with avascular bone grafting of 53.3% and
avascular bone grafting of 40.0%.
Locating the major connectors, indirect retainer, saddle type
and alloy: the lingual plate was used for 20/33, equal to 60.6%; indirect
retainers were mainly occlusal rest and cingular rest (100%), 51.5% of
major connectors were mono bar type, the length of the arches were to
1/2 toward tooth No.7 (90.9%); alloy was used for frame at 90.9%. Of
methods of setting up artificial teeth, articulator was used at 57.6%.
Type of claps and supporting type: 100% double Aker claps were
used for n2 abutment, T-claps were for n3 abutments at 81.8% and I-claps

were for n1 abutments accounted for 100%.
Mono Acker and double Acker claps were used mainly for 0,5mm
under cutting area with 75.8%; followed by 0.75mm area with 23.4%. T-
claps were for 0.5mm under cutting area (63.6%) and for 0.25 mm (36.4%).
Otherwise, I-claps were seen in under 0,25mm area, equal 69.6%.
Demand for fixing occlusion contact when mandible moved
horizontally: having statistical meaning with p < 0.0001. In which the
number of patients with demand for occlusal fix was 71.4% and for
articulator was 42.1%.
3.2.2. Effectiveness of functional and aesthetic rehabilitation
Effectiveness of functional and aesthetic rehabilitation was
evaluated by: time, method to treat bone defects and edentulous status.
3.2.2.1. Effectiveness of functional and aesthetic rehabilitation with time.
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Occlusion contact at the time of fitting the frame works:
12.1% of patients having occlusion contact at acceptable level.
Frame work retention by time: Declined gradually. After 1
year, the good level fell to 86.7%. After 2 years, the number was
76.9%; no patients at low level.
Masticatory function marked with scale of 100 with frame works:
after 2 months, there were 27.3% patients with good masticatory function
but after 1 month, the number increased to 39.4% and there was no low
level. After 2 years, 15.4% patients were at good level, 30.8% were in an
acceptable level and 53.8% were with low level.
Mastication indexes before and after treatment: the clear
improvement of masticatory function after fitting the frame work: good
level before fitting is 9.1% ,after fitting is 39.4%. The average level
before fitting 51.5% and decreased to 27.3%.
Mastication index before and after using frame works: the
number of patients whose mastication index before using frame was

50% was 36.4%; was 50-75 accounted for 63.6%; no patients with
mastication index over 75%; after using frame, mastication index which
was over 75 had 63.6% of patients, the rest was at 50-75.
MAI of the artificial jaw when observing the color of masticatory
wax after 1 month: 63.6% at good level, 33.3% at low level.
MAI when observing the color of masticatory wax before and
after fitting the frame works with real teeth: before using frame
works it was 81.8% but after it was 90.9%
MAI when observing the color of masticatory wax before and
after fitting the frame works in real teeth side and after fitting the
frame works in denture side: after fitting, MAI which was equal to
0.81±0.23 was much higher than before which was 0.67 ± 0.50; MAI of
artificial teeth was 0.26 ± 0.21.
The adjustment of patients to flame works (after 1 month)
Majority of patients feels stability at good level, meaning that can
eat and chew properly but still suffering movement (51.5%); the
effectiveness of chewing at average level (51.5%); good pronunciation
(84.9%), rehabilitation process caused pain for patients 27.3%, the
popular adjustment time was 2 weeks (48.5%).
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The change in pronunciation before and after 1 month:
Before using frame works, 72.1% of patients having trouble with
talking loud and fast, the rate afterward was 9.1%. The rate of patients
with normal pronunciation grew to 87.9%.
Aesthetics after fitting frame works: improved by 90.0%, after
1 year, the rate was at low level due to the shortage of observation time.
The patients’ satisfaction with flame works (after 1 month)
A large % of people felt confident when joining social activities
with 97.0%. 100% patients would recommend to others. The
satisfaction level was at 78.8%.

Compare the adjustment with mandibular major connector (1
month): there is no difference in the adjustment with 2 main types of
major connector which are lingual plate and dual plate (p > 0.05).
3.2.3.2 Effectiveness of rehabilitation of functionality and aesthetics
using bone grafting and condition of edentulous ridge
Compare the masticatory function of patients treated jaw
defects with different methods at the time of 2 weeks and 1 month:
a large % of patients using the avascular bone grafting had the
masticatory function at average level (70%). Patients using vascular
bone grafting (micro-vascular) had the excellent masticatory function at
88.9%, good level at 44.5% after 2 weeks and increased after 1 month.
3.2.3.3. Effectiveness of functional rehabilitation of frame work with
factors of teeth loss status in jaw arch
Masticatory functionality of patients after 2 weeks and 6 months:
patients with small losing molars and big losing molars with good
masticatory functionality had a hight rate of 36.4% at the time of 6
months and 27.3% at the time of 2 weeks. Patiens who had big losing
molars, small losing molars, incisors and 2-side-losing canines had
average chewing functionality: 18.2% at the time of 6 months; 12.1% at
the time of 2 weeks, low chewing functionality: 6.1% at the time of 2
weeks.
3.2.4. Effects of flame works over teeth, periodental and
mucosa
Evaluate the conditions of abutment after 6 months with the
criteria: the mobile level, tooth decay, GI, loss of adhension, bone
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resorption: after 6 months, 1 year, 18 months, majority of main teeth
were in the good conditions with 90%, at the time of 18 months, the
observation of GI index showed the large changes within the good and
acceptable level.

Impact of mandibular major connector to the mobile level of
teeth before 18 months: Majority of maxillary did not show the increase
of mobile level with 95.8% (lingular plate); 91.7% (double plate).
Impact of flame works on edentulous ridge: after the adjustment
time (1 month), there were 3 patients (9.09%) has the red swelling point
in the mucosa. This continued to the highest point of 18 months with
36.4% due to edentulous ridge resorption, and the frame work was not
interlocking.
At the time of 12 months, the demand for adding reline base
was 23.33%.
3.2.5. Observation of frame works quality
Quality of flame works: The broken rate of claps was at low
level of 4.5% in 18th month.
The adhension of color substance, lime residual after time period
There was appearance of color substance, lime residuals after 12
months. After 2 years, it had 38.5% color substance at plastic part,
61.5% ime residual at plastic part.
Observation of features of reasons leading to jaw defects:
After 1 years, 18 months, 24 months of restoration, 100% patients did
not suffer from the same disease.
CHAPTER 4
DISCUSSION
4.1. Clinical features and x-ray of the researched patients group
4.1.1. General characteristics of researched models
Most of patients are under 34 because that age relates to the time
when reasons of cutting the jaw bones are discovered or when patients
must be treated. Of these reasons, tooth enamel tumor is the most
common one. According to researches of Le Ngoc Tuyen, the majority
is young patients. Compared to researches of flame work rehabilitation
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or prostheses support implant which are to treat the patients with teeth
loss after the surgeries of segment, the Carlos’ study included 111
patients from 13 to 79 years old, in which the average age was 52, main
while Christian researched on 780 patients with 51.8 –year-old on
average.
Genders: In this research, the men: women rate is 54.5%: 45.5%
and this difference did not have any statistical significance. This ratio in
the research of Carlos and his colleagues on 102 patients with head-and-
neck section surgeries recreated the prosthesis support Implant was
69.6% and 30% for men and women respectively.
Depend on the classification of Kadota (2008) in Figure 3.1, there are
3 patients in A levels: remaining a part of the bone, which is a very good
condition for the prosthesis due to the occlusion contact has been stable, the
height of the edentulous ridge is higher than or equal to the mouth floor and
the mucosa on the edentulous ridge has no or little movement. 1 patient
accounted for 3.03% is cut condyle and shape condyle by cartilage. This is
really a challenge for the prosthesis.
Positions of losing teeth on jaw arch: Because the reason of the
teeth loss is defects in bones, patients often lose a group of teeth. The
largest percent belongs to the ones who lose big molars and small
molars with 36%, following by 24% of the ones who lose a group of big
molars + small molars + canine tooth + 1 incisor. These patients’
remaining teeth are still created with the arch shape in order to help
claps and components of the frame work to be stable. However, also
18.2% of patients have only big molars and small molars left which
make difficult for prosthesis.
There are 3 sources of bones and 2 methods to graft autologous
bone for patients with mandibular bone which are iliac crest bone, ribs
bone (avascular grafting), vascular fibular grafting (micro-vascular) The
rate of two patient kinds is similar (45.5% with 15/33 patients); the

research has 3 patients without bone grafting since they only lack a part
of bone and still remain bone base margin.
4.1.2. Complications, functions and facial aestheticism of the
researched patients group:
4.1.2.1. Complications and function of patients
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 Complications and functions after surgery:
The majority of patients eat soft foods for 1 month after surgery.
78% of them meet pronounced dysfunction as talking hardly and fast.
According to Murat Ozbek (2003) the close relationship between sound
and sound-making area can be affected when the sound-making area is
changed. There are 81.8% of patients who sometimes chew their lips,
cheeks and tongues due to neuromuscular disorders. These symptoms are
also seen in the studies of Julid (2008).
 The symptoms of temporomandibular joint, open-and-
close mouth operation and occlusion contact.
36.4% of the patients make sounds in the joints when they do
activities which show articular cartilage damages. This should be
prosthetic soon and recreate masticatory joint without any obstructing
points or occlusal trauma. The proportion of patients with increasing
condyle operating margin is 66.7%. The patients of this group mostly
have free iliac crest bone grafting with large changing occlusion
contact.
When evaluating open-and-close mouth activities based on Posselt
diagram, there are 78.8% of patients with zigzag shape of these activities
which greatly influence the temporomandibular joint. Especially, for the
patients who have mandibular bone gap, the jaw arches are deflected to the
surgery side if the mouth is maximized: 75.8% of them deviating to the
healthy-side mouth, while 72.7% is compared to the central axis of the
face, the deviation of the jaw arch is 1.2 ± 0.7 mm. The reason of this bias

toward the healthy side is that the muscles retraction and the asymmetric
bone with the healthy side. The deviations are different among patients.
72.7% of the patients have deflection toward the unaffected side compared
to the central axis of mandible when opening up their mouth maximally.
Some patients have deviation of 12mm and the average rate is 4.9 ±3.2mm.
In comparison with the study of Tong Minh Son, only 40% of
them have lost their teeth since last more than one year. Since they have
lost their teeth for a long time, the demand for joint adjustment is 47.06%.
Masticatory coefficient: It is equal to 50.2 ± 14.1; masticatory
function in 100 point scale is equal to 65.2 ± 15.0. For good group of the
masticatory function, the patients of this group can eat all kinds of food or
14
except only sticky or too hard foods. Fair group of patients can eat tough
meat. The number of patients whose masticatory functions are lower than
50% is 12 people accounted for 36.36%, in which 75% of them have
average dietary with normal foods such as meat, carrot, etc. None of 36.4%
of patients who just lose big molars and small molars has over-75%
masticatory coefficient. The patients with 50-70 points of masticatory
coefficient present for 63.6% in which the highest proportion belongs to the
good masticatory function group.
MAI method gives accuracy without too many complicated
techniques. MAI’s results reflect the masticatory characteristics, the
patients’ psychology as well as masticatory habits. MAI reflects not only
masticatory functions of teeth but also manipulated abilities by tongues,
cheeks and masticatory activities of oral cavity. The results from the
images show the abilities to crush food as evaluating to the masticatory
wax area with 50 µm thickness. On the graph 3.5, by observing the colors,
the masticatory wax blocks with good MAI account for 81.8% and the
value measured through the images is 0.67 ± 0.50.
4.1.2.2. Facial aestheticism

The morphological – aesthetic features of the face: Assessment
of the face’s asymmetry relates to the bone defecting position and the
rehabilitation because: horizontal branches and the mandible angle
define the width and the asymmetry of the face.
Assessing aesthetic factors of the face includes: the face is
symmetric or not, the lower surface layer is skewed or not, horizontal
branches are symmetric or not, jaw angle is convex or concave. Of the
patients, 60.6% have flat face in the surgery side, 24.2% have concave
lip sulcus in the surgery side, 36.4% have asymmetric and flat
horizontal branches as well as 87.9% have concave surgery angle. For
the patients who have concave surgery angle and asymmetric horizontal
branches area, their aesthetic factors are significantly affected.
4.1.3. Status of edentulous ridge, teeth and periodental
4.1.3.1. Status of edentulous ridge and frenums position
Status of the edentulous ridge created by grafting bone:
The height of the edentulous ridge is the first concerned factor
since it plays an important role in the dentures’ stability and determines
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the success of the rehabilitation. There are 5 patients who have vascular
bone graft with good edentulous ridge height, only one patient who
bone graft iliac crest had the same result. The straight piece bones up to
arches are difficult and do not ensure bearing the masticatory force on
the longitudinal axis from teeth arches to edentulous ridge.
Clinging positions of the buccal, lingual and labial frenums: In
many cases, buccal frenums are cut a part during sewing process. The
patients with buccal frenums which create scars from the contact point
with the last teeth next to tooth loss gap must be appointed to a pre-
prosthetic surgery.
4.1.3.2. Status of the teeth chosen as abutment
The teeth chosen as abutment all have good hard crown tissue

and periodontium.
 Dental
The patients in the research are young, do not have multi-decayed
teeth and periodontitis, therefore all abutment have integrity hard
structure of crowns, do not treat decayed teeth or dental pulp; there is
one patient who covered abutment by porcelain to improve the
occlusion contact. This is a very convenient condition to carry
equipment for frame work. However, because of the long-time chewing
in one side jaw, 42.05% of n2 abutments are worn occlusal surface, 05
mm in depth of ivory. This causes difficulty in grinding teeth to create
rests and claps.
 Status of the periodental:
According to Yoav Grossmenn: the important issues when
choosing abutment is the ratio between the length of the crown and the
tooth root: the smaller the ratio, the better the abutment. This ratio is
determined in X-ray of periopex.
85.26% of patients in this research have this area in a good status,
which is also an advantage in frame work rehabilitation.
 The mobile level of abutment: Based on ages, 63.2% of the
patients whose abutments have mobile degree 1 are in 35-60 years old.
In general, the rate of teeth in mobile degree 1 is 19 /95 (accounted for
20%). These teeth usually have traumatic occlusion contact when the
patients have not had dentures, then their mobile level will decrease
16
after prosthetic treatment. According to Tong Minh Son’s research, the
abutment with mobile degree 1 at n1 teeth and n2 teeth are 41.41% and
23.6% respectively; and for the mobile degree 2, these ratios are 9.1%
for n1 teeth and 8.14% for n2 teeth.
 The shape of the abutment’s root: in the research, most of
abutment’s root is long and thin which is not really a favorable shape

for abutment of frame works.
4.2. The effects of functional and aesthetic rehabilitation of frame work.
4.2.1. Treatment to rehabilitate the frame work
4.2.1.1. Pre-rehabilitating treatment
There are two issues concerned most: the rotation flap surgery,
cutting scars and stress reduction and adjustment of occlusion contact in
patients who have occlusal obstacle points.
4.2.1.2. Frame work design
 Types of major connectors:
60.6% of major connectors in the research are the lingular plate,
remaining are dual plate bar or no plate bar. Dual plate bars is used in
case other teeth’s cylinders are toward the plate (Wilson curve change).
As far as David is concerned, the plates have stable effect and
strengthen the connection of the rests to enhance supports. For John
Beumer, the first choice is plate. Following research by Kim, SEong-
Kyun (2007): On the biomechanics of abutment, when the cylinders are
linked together, the force to the abutment will decrease compared to the
abutment standing individually. Then the plate is suitable.
 Types of claps: Claps play an important role in retention of
dentures and in protecting frame work from the torsional by rests. Kinds
of claps are chosen by position and the size of the defecting area thanks
to the surveyors. Big molars and small molars use circumferential
claps, while incisors and canine teeth use bar claps. Bar claps is
better in retention than circumferential claps, but not as stable as
the former. 100% double Acker claps are in n2 or n3 abutment. In
the tooth which is next to the losing teeth gap, I-claps are preferred
with 100%, following by T-claps at 81.8%. This result is consistent
with documents and researches of John Beumer. The leaning
incisors with the lost size < 0.25mm will be used I-claps; 69.6% of I-
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claps is suitable with the abutment which have 0.25mm lost size.
For single or double Acker claps, they are 78.8% of them used for
abutment with 0.5mm lost size and 23.4% of them used for
abutment with 0.75mm. T-claps are more popular with abutment
with lost size of 0.5mm (63.6%).
 Types of saddle: The patients whose edentulous ridges are
convenient for rehabilitation and have high bearing level are appointed
to use lattice work saddle: 7/33 patients (21.21%); lattice bridge saddle
are for patients with inconvenient edentulous ridges but short defecting
gap (9/33 patients, accounted for 27.27%); for patients with narrow
width and long defecting gap, saddle nail head are chosen to avoid the
torsional of major connetor: 17/33 patients as 51.51%. These kinds are
mentioned about their advantages and disadvantages by Stewart. In
comparison with studies of Zlataric, Walid and Graham, it is mainly
lattice work saddle.
 Setting up artificial teeth
With the principle of reducing the force impacting to the
edentulous ridge by grafting bones as much as possible, and
simultaneously reducing the length of arm lever to help frame work
more stable, 100% of patients in the research are making teeth to ½
close to teeth number 7 in the opposite side, 100% of the teeth are non-
surgery or surgery a half (unclear teeth angle). Researches by Masako
Yanagawa and associates (2004) and by Sueda and K.Fueki (2003)
confirmed that there is no difference in masticatory force between this
making teeth method and making teeth with full length of toothed
segment with 30 degree of teeth angle.
 Functional surgery mold making method (selectively
pressure mold: segmented with neural molding or not):
75.8% of the 1
st

mold making is by personal mold with Silicone
material. These patients have the grafting bone area that make
edentulous ridge lower than mouth floors, floating mucosa above. 100%
of cases are conducted the 2
nd
mold making after trial flame works.
The advantage of making pressure molds selectively is that the
edentulous ridge is taken mold under functional status, meaning that the
mucosa organization and under-mucosa are under the pressure. This leads
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to better bearing level. In Tong Minh Son’s research, this ratio is 45%.
For the technology of making molds selectively combined to
neutral gap: both taking molds of edentulous ridge area and taking
molds of rehabilitated area (the middle area to tooth arches remains
with the activities of lips, cheeks, tongues and cells in the mouth floor
area) by Silicone and soft plastic (14 patients as 42.2%), by
thermoplastics compounded with soft plastics (11 patients – 33.33%),
Silicone ensures the accuracy and lasts longer time so it is suitable with
long losing teeth gap.
In research of John B.Holmes, he says: No matter what partly
making mold or making mold with individual spoons, using algienate
usually causes movement of pattern; hence it needs to be used materials:
Keer compound, Silicone, Zinc oxit. Along with Mizuuchi’s idea (2002),
both of making functional surgery molds and making molds partly with
rehabilitation gap do not increase durability for the abutment.
 Adding reline base by soft plastic: Most of patients (28
people, accounting for 84.85%) with movement edentulous ridge are
added reline base by soft plastic. Adding reline base is made
immediately after fitting the frame works: patients do not feel pain or
obstacle, wear jaw then use adding reline base. As statistic, 7 patients,

accounting for 21.21% have to add reline base 2
nd
time after 1 year, 4
patients have to add reline base 2
nd
time after 2 years. These one in this
group all have mucosal cell in movement edentulous ridge which needs
a period to bear the pressure. Shu Mon-Hui (2001) also confirms the
effectiveness of adding reline base for patients with defects on
madibular bone rehabilitated by frame works: improve the stability and
do not stagnate food under the jaw floor.
4.2.2. Effectiveness of functional and aesthetic rehabilitation of
frame work
The patients with defects on mandible grafted bone care about
recovery of masticatory function and pronounced function. Good
masticatory function depends on: the retention of frame work, occlusion
contact, and adaptation of the patients’ dentures. Pronounced function is
enhanced by covering the shortages of organization after surgery and
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depends on the dentures adaptation.
 The retention of the frame work: Evaluation at the time of
fitting: most of frames are able to retain well (97%). It is contributed
by: assigning right kind of hook for each abutment and lost area
position as well as the teeth arches are similar to rehabilitated gap which
help to avoid the movement. Review at the time of 1 month after
wearing frame works: Same results as at the 1
st
evaluation. According to
Pham Le Huong’s research, the good retention ration is just 90% at 1
week after fitting the flame work.

 Occlusion contact
At the installation time, 81.8% of patients meet joint touching on
all teeth and for the remaining (18.2%), the teeth do not touch the joints
(as the results on graph 3.9); these patients have teeth misalignment and
occlusal changes but do not have orthodontic surgery before
rehabilitation.
 MAI
After a week, the patients’ frameworks are adapted at an
acceptable level, but it is often better after one month, and the research
also applies MAI index to assess the masticatory abilities in the denture
side. Compared to the side without surgery, the masticatory function
increases from 81.8% (pre-installation) to 90.9% (after installation) for
better group; and from 12.1% (pre-installation) to 0% (after installation)
for poorer level group. MAI value measured by images also
demonstrates the differences: before: 0.67 ± 0.50 and after: 0.81 ± 0.23.
Based on the chart 3.13, the colors of the wax block in the real
teeth side are compared between before and after installation, and the
good ratio rises from 81.8% to 90.9%. To explain, during the jaw
design process, the obstacle point of occlusion joint was grinded; after
installing the bearing points in chewing surface also imprve the
touching joints of teeth.
According to Asakawa (2005): MAI index in new dentures is
0.70 ± 0.68, and in old dentures in which arfiticial teeth do not have
good touch point with opposite occlusion contact, it is -0.11 ± 1.13
According to Wacharasa (2005), MAI index of the patients with
rehabilitation of 2-4 teeth is 0.65 ± 0.50 for dentures and 1.06 ± 0.64
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for real teeth.
MAI index in our research is 0.26 ± 0.71.
 Masticatory function on a scale of 100: the rate of patients

who have good masticatory function are 27.3% after 2 weeks and
39.4% after 1 month. It means that masticatory fuction is improved with
artificial jaw adaptation. To compared between before and after fitting,
the percentage of patients who have poor masticatory fuction decrease
from 51.5% to 27.3% respectively.
 Masticatory index: Before installing flame works, no patient
own the masticatory index of 75, but after fitting flame works, there are
63.6% of patients with >75 points of this index. This demonstrates that
touching occlusal contact meets the requirements.
 Pronunciation: Because the patients in the research rehabilitate
many organizations then they take more time to be familiar with dentures
than the patients who only lose teeth. Therefore, after 1 month, we also
make a question to assess the prounciation: 87.8% of the patients have
changes after fitting flame work and pronounce as normal.
 Aesthetics: At installation time, mainly evaluating the
improvement of the faces.
4.2.3. The impact of flame works on teeth and periodental
The hard structure of teeth: the good rate is 100%. Research of
Yeung A.L.P. showed that after 189 patients wearing the flame works
made by alloy for a period of 5-6: new tooth decay (crown, tooth root, root
+ crown) the contact area with flame works: 8.5%, non-contact area with
flame work: 4,5%; in 91 rests prepared on teeth to weld, 8,8% of the tooth
decay relapse.
Structure of periodental mobile level of abutment and other teeth:
review of OHI index of main teeth in accordance with GI of time period
after 6 months, 12 months and 18 months, the good GI index is 91,18%
(6 months) of n1abutment, right behind the toothless areas. These
abutments before rehabilitation already have a better GI then others
which is far from toothless areas (n2).
Both OHI and GI of abutment and the rest after 1 year have the good

results of 2 teeth types of about 50%
According to Mine K. (2009), after 12-65 months of wearing
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frame, 38 patients with the average age of. 622: 47% abutment and 32%
normal teeth had GI at 2 - 3; the difference has statistical meaning.
According to Kern M., after 10 years, 147 patients with 1209 teeth (593
abutments, 616 normal teeth) use Periotest as the subjective method:
there is no difference with statistical meaning between main teeth and
normal teeth, showed by the indexes.
According to Amaral, in comparison between abutment and the
others, it showed the difference in OHI and GI index after 10 years.
 Periodental conditions and mobile level of abutment:
According to the result at the 3.30, reviewed the results after 18 months
of losing adhesion around the main teeth n1 of the average group and at
main teeth n2 as given in table 3.29, after 12 months
Periodontal pockets: As Yeung A.L.P. reviewed after 5 years,
periodontal pockets of molars 13.2%, of incisors 7.1%. The areas which
not contact with frame works have the higher number. As Mine K
(2009), the mobile level of abutment: 0.58 ± 0.55, of normal teeth: 0.13
± 0.41. Gingival pockets: abutment: 2.71 ± 0.73; normal teeth: 2,61±
0,55. The difference has no statistical significance.
CONCLUSION
After studying on rehabilitation frame works for patients losing
their mandibular bone and have received bones grafting treatment or
bone base still remains, we have come to following conclusions:
1. Clinical features, X.ray of the group of patients in the reasearch.
- General feature of the patient group: young patients under 34
years old account for 54.5% of which male is 54.5%. The major causes
for bone defects is the result of illness treatment operations for
mainly tooth enamel tumour: 81.8%. Method of graft iliac crest bone

without vasculator is seen most in 2
nd
stage with 91.9% while avascular
iliac crest bone grafting is mainly in the same stage with segment
accounted for 69.2% with mono bone graft.
- Tooth groups often been lost are mainly big molar + small
molar:36,4% or half of jaw arch: 24,2%.
- Masticatory function: on the scale of 100, the group of good
level account for 9.1%, average level: 39.4% and poor level: 39.4%.
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Masticatory coefficients < 50% account for 36.4%.
- Occlustion contact: Temporo-mandibular joint working with noise:
36.4%, increase in moving amplitude: 66.7%, change curve of Spee, change
curve of Wilson, change diagram of Posselt.
- Aesthetics: flat lower face 66.7%, concave jaw angle: 69.7%,
asymmetric horiziontal axis: 63.6%.
- Pronunciation: 72.8% get difficult in speaking loudly and
fast,12,1% difficult to pronunce s, tr sounds with the symtoms of
sounds lost or sounds distort under sounds resonance.
- Maximally mouth opening with jaw arch toward the surgery
side: 75.8%, toward the not-operated side: 72.7%.
- MAI: in observation colors of the masticatory wax, 81.8%
is good quality, average quality: 6.1%, low quality: 12.1%;
variation: 0,67 ± 0,50.
- Panorama result: Grafting bone height is expressed at 3 levels: >
15 mm with 9.1%; từ 10 - 15mm with 39.4%, < 10mm with 51.5%.
2. Evaluation on functional and aesthetics rehabilitation of frame
work in treating teeth lost on the group of patients in the reaearch:
2.1. Functions:
Frame works prosthesis insists on the rehabilitated results of

masticatory function, aesthetics, pronunciation of patients lost their
mandible after being cured by bones grafting or simple bone taking.
- Jaw rehabilitation rate: > 90%
- Occlusion contact: 81.8% at good condition
- Masticatory function at good and average levels is 60%,
masticatory coefficient 50 - 75: 36.4%; upper75: 63.7%.
- Pronunciation: Getting difficulties in speaking loudly and fact is
restricted to only 12.1%; Difficulties with pronuncing s và tr is limited
to 3,0%.
- Occlusion contact: change the curve of Spee and of Wilson is: 6.1%.
- MAI index shows the evaluation on masticatory function is
23
objective.
+ Observing masticatory wax color: of artificial jaw, 63.7% is
good, after treatment 90.9% is good.
+ Value on image: after getting treatment MAI = 0.81 ± 0.23;
Artificial jaw: 0.26 ± 0.17.
- Significant change comparing before and after treatment:
Difficulties in speaking loudly and fast: Before:72.7%; after: 12.1%.
2.2. Aesthetics: Aesthetics at the period 1 month and 6 months
after treatment reach 90% is an important element to evaluate.
2.3. Effects of frame works on teeth, periodental and neighbor
mucosa.
- Following elements of abutment at the points 6 months, 12
months and 18 months after treatment are all at good level.
- The difference at abutment and the rest teeth is that do not have
statistical value at teeth loosing and teeth hygience.
- Jaw quality: broken claps appears after 18 months
RECOMMENDATION
1. Increase professioal knowledge for branch medical centers on

diagnosing and treating illness at jaw. llness soon diagnosed can save
more teeth, sustanable occlusion contact and good results in presthetic
treatment.
2. Widely application the technique to graft crest bone with
microvasculator especially double crest bone grafting to create good conditions
for teeth presthetic treatment
3. The patients with mandibular defects need to make prosthesis by
frame wroks early as possible with the best of within 6 month to 1 years, in
order to limit defects, rehabilitate functions well for patients and avoid the
disorder of functions and aesthetics.
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