Effectiveness of orthognathic surgery and the suitability with Vietnamese harmonious faces in class III malocclusion patients

Class III malocclusion affects negatively on health, quality of life and psychology. Orthodontic and orthognathic surgery is necessary for adult patients with skeletal class III malocclusion to achieve good function and aesthetic. The subjects were 35 patients at Hanoi National Hospital of Odontostomatology, Viet Duc University Hospital, and Hong Ngoc Hospital from April 2017 to September 2018.

EFFECTIVENESS OF ORTHOGNATHIC SURGERY AND THE SUITABILITY WITH VIETNAMESE HARMONIOUS FACES IN CLASS III MALOCCLUSION PATIENTS

Nguyen Hoang Minh¹, Pham Hoang Tuan 2 , Hoang Thi Doi 3 ,

Nguyen Thi Thu Phương 1 , Le Van Son 1

¹ School of Odontostomatology, Hanoi Medical University

²Hanoi National Hospital of Odontostomatology

3 Hanoi Medical College

Class III malocclusion affects negatively on health, quality of life and psychology Orthodontic and orthognathic surgery is necessary for adult patients with skeletal class III malocclusion to achieve good function and aesthetic The subjects were 35 patients at Hanoi National Hospital of Odontostomatology, Viet Duc University Hospital, and Hong Ngoc Hospital from April 2017 to September 2018 This was a quasi-experimental study with self- comparison, 1 month, 6 months and 12 months follow up Orthog-nathic surgery pushed maxilla forward and set back the mandible, corrected occlusion to skeletal class I intermaxilla reduced mental prognathism, corrected cross bite, dental decompensation The relationship among upper and lower lips with nose and chin were aesthetically improved Twenty patients, which were followed up after 12 months, had stable post-operation results In comparision with harmonious facial index of Kinh ethnic in Vietnam, 80% patients achieved skeletal harmony, 85% patients achieved dental harmony and 80% achieved soft tissue harmony, 100% patients had quality of life improved The more harmonious index patients acquired, the higher quality of life they achieved In order to improve surgical effectiveness, harmonious facial index is essential in planning and pre-surgical simulation

Keywords: class III malocclusion, orthognathic surgery, harmonious faces

I INTRODUCTION

Malocclusion is the incorrect dental

relation between teeth of two arches

The rate of malocclusion is high, over

50% worldwide In America and Asian

countries, this rate can be as high as 70% [1] Class III malocclusion comprises a high percentages in the population, up to 35% [2; 3] Class III malocclusion is the etiology of occlusal trauma, functional decrease, and an increased risk of dental diseases, facial aesthetic and psychological problems [4] Treatment for skeletal class III malocclusion is quite necessary to improve quality of life [5] Most of adult patients with skeletal malocclusion, especially

Corresponding author: Nguyen Hoang Minh,

School of Odontostomatology, Hanoi Medical

University

Email: drnguyenhoangminh@gmail.com

Received: 27/11/2018

Accepted: 15/03/2019

class III malocclusion, need a combination

of orthodontic and surgerical treatment

to achieve good outcomes in function

and aesthetic [6] However, treatment for

skeletal malocclusion is always a challenge

for orthodontists and surgeons Maxillary

Lefort I osteotomy and bilateral sagittal split

osteotomy ramus are commonly applied

worldwide, providing good outcome in

aesthetic and function in three dimensions,

as well as post operative stability [7; 8]

Domestic longitudinal studies on

orthognathic surgery for patients with

skeletal class III malocclusion is very

limited The Vietnamese harmonious facial

index is an important factor in assessing

the effectiveness of surgery; hence, the

application of this index in orthognathic

surgery must be calculated Thus, we

conducted this study with two objectives:

1 To evaluate the effectiveness and

stability of orthognathic surgery in class III

malocclusion patients

2 To evaluate the suitability with the

Vietnamese harmonious facial index and

satisfaction in skeletal class III malocclusion

orthognathic patients

II Method

1 Subjects

Skeletal class III malocclusion patients

were treated with preoperative orthodontic

and orthognathic surgery in Hanoi (Hanoi

National Hospital of Odontostomatology,

Viet Duc University Hospital and Hong Ngoc

Hospital) from April 2017 to September

2 Study method

Quasi-experimental study with self - comparison before operation (T0) and after operation at point in time 1 month (T1), 6 months (T6) and 12 months (T12) follow up; sample size: N=34 (p = 0.722 in sample size formula) At the moment, 35 patients have been followed up for 1 month, 32 patients have been followed up for 6 months and

20 patients have been followed up for 12 months Other patients are still followed up Before operation, all patients were examined, took cephalometric Xrays All patients were operated with maxillary Lefort

I osteotomy and bilateral sagittal split ramus osteotomy

Following and evaluating the effectiveness and stability of orthognathic surgery in class III malocclusion patients

Result assessment after 1 month (T1),

6 months (T6) and 12 months (T12): clinical examination, cephalometric index measurement, (skeletal, dental and soft tissue index)

Evaluating the effectiveness of surgery is evaluation the changes in facial index before and after surgery by comparing skeletal, dental and soft tissue index in preoperation (T0) and 1 month postoperation (T1)

Evaluating the stability of surgery is evaluation the changes in facial index through time after surgery by comparing skeletal, dental and soft tissue index

in 1 month postoperation (T1) and 6 month postoperation (T6) and 12 month

Assessment of the suitability with

Vietnamese harmonious facial index in

skeletal class III malocclusion patients

Assess the suitability with Vietnamese

harmonious facial index is assess the

suitability between postoperation facial

index and Vietnamese harmonious facial

index by comparing patients’ cephalometric

indexs after 12 month postoperation with

Vietnamese Kinh Ethnic harmonious facial

index in National Research in School of

Odonto & Stomatology – Hanoi Medical

University

Assessment of patient satisfaction

after orthognathic surgery correcting

class III malocclusion Orthognathic

Quality of Life Questionnaire (OQLQ) was

used to evaluate patients’ quality of life and

satisfaction [9] Average index: ≤ 2: good

quality of life; 2-3: moderate quality of life; ≥

3: poor quality of life

3 Data analysis

Continuous variables were skeletal,

dental and soft tissue index (SNA, SNB,

ANB angle, A-V, B-V, Pg-V, Wits, over jet,

over bite, U1-SN, Is-V, L1-MP, Ii-V, Li-E,

Ls-E, Cm - Sn – Ls angle, Li - B' - Pg' angle, Ns

- Sn - Pg’ angle) measured in Cephalometric

X – rays which were analysed with SPSS

16.0 software If the variables achieved normal distribution, pair T - test was used

If the variables cannot achieved normal distribution, non-parametric test (Wilcoxon signed rank test) was used

4 Ethical Considerations

This study belongs to National research

of School of Odonto & Stomatology – Hanoi Medical University, which had been approved this study according to Decision

No 202/HĐĐĐĐHYHN, signed on October 20th 2016

III Results

1 Clinical and X-ray characteristics

of class III malocclusion orthognathic patients

1.1 Clinical characteristics

There were 14 male patients (40%); 21 female patients (60%) in the study with 100

% concave profile There were twenty one long facial cases (60%) and 14 mesofacial cases (40%) No short facial case were observed

The average overjet was -4 ± 2.16 mm and the average overbite was 1.49 ± 0.66 mm

1.2 X-ray characteristics

Table 1 Skeletal – dental – soft tissue index on cephalometric by gender

(Male – Female)

U1 - SN (degree) 114.05 ± 9.55 108.13 ± 8.07 > 0.05

L1 - MP (degree) 85.05 ± 11.13 88.13 ± 6.73 > 0.05

Cm - Sn - Ls (degree) 73.37 ± 12.30 87.66 ± 13.18 < 0.01

Li - B’ - Pg’ (degree) 147.10 ± 10.29 146.10 ± 11.61 > 0.05

Ns - Sn - Pg’ (degree) 186.43 ± 2.90 184.78 ± 3.56 > 0.05

Comment: Small SNA, large SNB , negative ANB, negative Wits Maxillary retrognathism, mandibular prognathism Small Ls – E retrognathic upper lip, large Li – E prognathic lower lip Acute nasolabial angle (Cm – Sn – Ls) Obtuse labiomental angle (Li – B’ – Pg’) Large facial angle (Ns – Sn – Pg’) featured for concave profile The differences of SNB, Li-E, Cm-Sn-Ls were statistically significant between males and females

2 Effectiveness and stability after orthognathic surgery in class III malocclusion patients

2.1 Skeletal, dental and soft tissue index in 1 month postoperation

Table 2 Skeletal, dental and soft tissue index 1 month posoperation (T1) in

comparision with preoperation (T0)

(T0 – T1)

U1 - SN (degree) 110.50 9.05 105.50 9.64 < 0.001

Cm - Sn - Ls (degree) 81.94 14.51 92.56 4.29 < 0.001

Li - B’ - Pg’ (degree) 146.50 10.96 134.19 5.23 < 0.001

Ns - Sn - Pg’ (degree) 185.44 3.37 164.95 2.62 < 0.001 Comment: Forward movement of the maxilla (SNA, A-V increased), backward movement

of the mandible, prognathic chin reduced (SNB, B-V, Pg-V reduced) Class I intermaxillary relationship was achieved, cross bite was corrected Forward movement of upper incisors (Is-V increased), backward movement of lower incisors (Ii-V decreased) Increased angle between lower incisors and mandibular plane (L1-MP), decreased angle between upper incisors and cranial plane (U1-SN) Forward movement of upper lip (Ls-E increased), backward movement of lower lip (Li-E decreased), facial angle decreased (Ns-Sn-Pg’) Nasolabial angle was larger (Cm-Sn-Ls increased) and labiomental angle was smaller (Li – B’ – Pg’ decreased) in comparision with pre-surgery index Above changings were statistically significant (p < 0.05) Overbite changing is not statistically significant (p > 0.05)

2.2 Skeletal, dental and soft tissue index in 6 month postoperation

Table 3 Skeletal, dental and soft tissue index in 6 month postoperation (T6) in

comparision with 1 month postoperation (T1)

(T1 - T6)

Cm - Sn - Ls (degree) 92.30 4.26 96.36 4.60 < 0.001

Li - B’ - Pg’ (degree) 133.89 5.33 129.22 4.51 < 0.01

Ns - Sn - Pg’ (degree) 165.17 2.63 166.59 2.62 < 0.001 Comment: Changing in maxillary index (SNA, A - V) was not statistically significant (p

> 0.05) Forward movement of mandible and chin (SNB, B-V, Pg-V increased) (p < 0.05) Reduction of ANB angle was statistically significant, class I intermaxillary relationship Overjet was statistically significantly decreased (p < 0.05), changing in overbite and dental index (U1 - SN, Is - V, L1 - MP, Ii - V) were not statistically significant (p > 0.05) Upper and lower lips were set back E-line Facial angle (Ns - Sn - Pg’) was increased Larger nasolabial angle (Cm - Sn - Ls increased), smaller labiomental angle (Li - B' - Pg' decreased) in comparision with pre-surgery Those changings were statistically significant (p < 0.05)

2.3 Skeletal, dental and soft tissue index in 12 month postoperation

Table 4 Skeletal, dental and soft tissue index in 12month postoperation (T12) in

comparision with 6 month postoperation (T6)

(T6 - T12)

Cm - Sn - Ls (degree) 94,04 3,52 94,22 4,02 > 0,05

Li - B’ - Pg’ (degree) 132,47 4,31 133,79 7,87 > 0,05

Ns - Sn - Pg’ (degree) 166,72 2,88 167,43 3,55 > 0,05 Comment: Skeletal, dental and soft tissue index in 12 month postoperation was similar to

6 month postoperation index (p > 0.05)

3 The suitability with Vietnamese harmonious facial index and satisfaction in skeletal class III malocclusion orthognathic patients

3.1 The suitable rate with Vietnamese harmonious facial index

Figure 1 Suitable rate with Vietnamese harmonious facial index

Comment: Among 20 patients got 12 month postoperative following up, there were 16 cases having harmonious skeletal index (80%), 17 cases having harmonious dental index (85%) and 16 cases having harmonious soft tissue index (80%) Four cases that did not achieve the harmonious skeletal, also fail to achieve the harmonious soft tissue index

3.2 Quality of life changing after surgery

Figure 2 Quality of life changing after surgery

Comment: There was no good quality of life case before surgery Quality of life was improved after surgery, there were 17 cases having good quality of life (85%), 3 cases having moderate quality of life (15%) and there was no case having poor quality of life

Figure 3 Quality of life and harmonious face

Comment: 100% cases had good quality of life in group harmonious face achieved Among

4 cases that could not achieve the harmonious face, there were 3 patients having moderate quality of life and 1 patient having good quality of life The relation between harmonious face and quality of life was statistically significant (p < 0.01)

IV Discussion

1 Clinical and X-ray characteristics in

skeletal class III orthognathic patients

In our study, proportion of females

(60%) was higher than males (40%) due to

the fact that females are more concerned

about aesthetic than males Index measured

on cephalometrics suggested retrognathism

maxilla, prognathism mandible, dental

compensation (lingual inclination of lower

incisors, labial inclination of upper incisors),

retrognathism upper lip and prognathism

lower lip, acute nasolabial angle, obtuse

labiomental angle, large facial angle

These results were appropriate with studies

conducted by Aydemir [7], Le Tuan Hung

[10], I-Ming Tsai [11] Remarkablely negative

ANB and Wits, which suggested large

deviation in anterior-posterior dimension

between maxilla and mandible These

are characteristics of patients who need

orthognathic surgery

2 Effectiveness and stability after orthognathic surgery in class III malocclusion

1 month postoperation, our study observed forward movement of the maxilla, backward movement of the mandible and intermaxillary relationship was changed from class III (preoperation) to class I Overjet was increased to positive average value, cross bite was corrected The angle between lower incisors and mandibular plane was increased, the angle between maxillary incisors and basal plane was decreased, dental decompensation was achieved (palatal inclination of upper incisors and labial inclination of lower incisors), dental esthetic was improved Soft tissue was also changed: forward movement of upper lip, backward movement of lower lip, decreasing facial angle, increasing nasolabial angle

as well as decreasing labiomental angle

in comparion with preoperation These changes significantly improved facial

aesthetic, the relationship between upper

lip and nose, lower lip and chin Our result

was appropriate with studies conducted by

Ghassemi, Le Tan Hung, I-Ming Tsai [8; 10;

11]

At 6 month postoperation, the maxilla was

stable The mandible was unstable, which

moved forward, reducing overjet However,

the intermaxillary relationship was still class

I, and positive overjet value remained

Ghassemi, Le Tan Hung and I-Ming Tsai also

observed unstable mandible after surgery

[8; 10; 11] This unstable condition was

due to traction of muscle underneath the

mandible, excessive backward movement

of the condyle in fossa, changing in

direction and force of the masseter muscle

and pterygoid muscle, which caused a force

pulling the gonial upward and forward [12]

About soft tisse, higher esthetic relationship

among nose, lips and chin was achieved

(less acute nasolabial angle and less

obtuse labiomental angle), which may be

due to completely disappearance of swollen

situation in comparision with 1-month after

surgery 20 patients who had been followed

up 12 months had stable skeletal, dental

and soft tissue index Other patients will be

followed up till 12-month after surgery

3 The suitability with Vietnamese

harmonious facial index and satisfaction

in skeletal class III malocclusion

orthognathic patients

Among the 20 patients who completed

12-month follow-up, there were 16 cases

having harmonious skeletal index (80%),

17 cases having harmonious dental index

soft tissue index (80%) Patients who had harmonious skeletal index also had harmonious soft tisse index Thus, skeletal index is important, which need to achieved

in planning to help creating harmonious soft tissue index because it is difficult

to predict accurately soft tissue index while planning Dental decompensation, less acute nasolabial angle, less obtuse labiomental angle, decreasing facial angle helps improving facial esthetic significantly After surgery, the quality of life had been raised, and patients were satisfied with their facial changing, which was similar to studies

of Wee [13] The more harmonious index achieved, the better quality of life those patients acquired Therefore, harmonious facial index should be applied in planning and preoperative simulation to increase surgical effectiveness and patient’s quality

of life

V Conclusion

Maxillary Lefort I osteotomy and bilateral sagittal split ramus osteotomy were efficient

in correcting skeletal class III malocclusion After surgery, the maxilla moved forward, the mandible moved backward, class I intermaxillary relationship was achieved,

as well as backward movement of chin, correction of cross bite and dental decompensation (palatal inclination of upper inciors and labial inclination of lower incisors), thus esthetic was significantly improved Forward movement of upper lip, backward movement of lower lip, decrease

of facial angle, increase of nasolabial angle