QUALITY OF LIFE ASSESSMENT IN PATIENTS WITH MALOCCLUSION 
UNDERGOING ORTHODONTIC AND ORTHOGNATHIC TREATMENT
Ljiljana VUČIĆ
1
, Branislav GLIŠIĆ
1
, Uroš VUČIĆ
1
, Jelena DRULOVIĆ
2
, Tatjana PEKMEZOVIĆ
3*
1
University of Belgrade, School of Dental Medicine, Department of 
Orthodontics, Dr Subotica 8, 11000 Belgrade, Serbia
2
Clinic of Neurology, Clinical Center of Serbia, Faculty of Medicine, 
University of Belgrade, Dr Subotica 6, 11000 Belgrade, Serbia
3
University of Belgrade, Faculty of Medicine, Institute of 
Epidemiology, Visegradska 26A, 11000 Belgrade, Serbia
Received: Jul 5, 2019
Accepted: May 5, 2020 
Original scientific article
*Corresponding author: Tel. + 381 11 360 70 62; E-mail: pekmezovic@sezampro.rs
10.2478/sjph-2020-0018 Zdr Varst. 2020;59(3):137-145
137
OCENA KAKOVOSTI ŽIVLJENJA PRI PACIENTIH Z MALOKLUZIJO, PRI 
KATERIH SE IZVAJA ORTODONTSKO IN ORTOGNATSKO ZDRAVLJENJE
© National Institute of Public Health, Slovenia. 
Vučić L, Glišić B, Vučić U, Drulović J, Pekmezović T. Quality of life assessment in patients with malocclusion undergoing orthodontic and orthognathic treatment. 
Zdr Varst. 2020;59(3):137-145. doi: 10.2478/sjph-2020-0018.
ABSTRACT
Keywords: 
malocclusions, 
quality of life, 
orthodontic therapy, 
orthognathic therapy     
IZVLEČEK
Ključne besede: 
malokluzije, kakovost 
življenja, ortodontsko 
zdravljenje, 
ortognatsko zdravljenje
Introduction: The objective of this study was to assess pre-treatment quality of life and the relevant clinical variables 
in adult patients with malocclusion in order to improve orthodontic treatment strategies. 
Methods: The study was conducted in 240 consecutive adult patients with malocclusions divided into two groups: 
patients for whom an orthodontic treatment plan was considered, and patients for whom an orthognathic treatment 
plan was selected. Patients were examined between December 2015 and February 2017, at the School of Dental 
Medicine, University of Belgrade. Malocclusion severity was recorded using the Peer Assessment Rating index pre-
treatment score. Skeletal malocclusion parameters were measured using lateral cephalometric radiographs. Quality 
of life was assessed by means of a generic questionnaire (Medical Outcomes Study Short Form-36 (SF-36)), and the 
disease-specific Orthognathic Quality of Life Questionnaire (OQLQ). 
Results: There were significant differences in the mean values of the OQLQ domain scores between orthodontic and 
orthognathic patients. Patients for whom orthodontic treatment was planned had statistically significantly lower 
scores in comparison to those for whom orthognathic treatment was planned. This was the case in all OQLQ domains 
except for “Awareness of facial deformity”. Statistically significant correlations (p<0.05) were presented between 
OQLQ scores and following demographic and clinical variables: gender, age, malocclusion severity, maxillary and 
mandibular sagittal, maxillary vertical, and lower incisor positions, intermaxillary angle, and the Beck Depression 
Inventory and Beck Anxiety Inventory levels. The independent predictors for the planning of orthodontic and 
orthognathic treatment in patients with malocclusion were two OQLQ domains, “Facial aesthetics” and “Awareness 
of facial deformity”, as well as total OQLQ score, after adjustment for demographic characteristics, skeletal 
parameters, anxiety and depression. 
Conclusions: Our findings suggest that patients for whom orthodontic treatment was planned demonstrated better 
quality of life according to the OQLQ scores in comparison to those for whom orthognathic therapy was planned. 
Uvod: Cilj te študije je bil oceniti kakovost življenja pred zdravljenjem in zadevne klinične spremenljivke pri odraslih 
pacientih z malokluzijo, da bi lahko izboljšali strategije zdravljenja. 
Metode: V študijo smo vključili 240 zaporednih odraslih pacientov z malokluzijo, ki smo jih razdelili na dve skupini: 
v prvi so bili pacienti, pri katerih je bil predviden načrt ortodontskega zdravljenja, pri drugi pa je bil izbran načrt 
ortognatskega zdravljenja. Bolnike smo pregledovali med decembrom 2015 in februarjem 2017 na Stomatološki 
fakulteti Univerze v Beogradu. Resnost malokluzije smo evidentirali z rezultatom pred zdravljenjem po indeksu PAR 
(Peer Assessment Rating). Parametre skeletne malokluzije smo izmerili na lateralnih cefalometričnih radiogramih. 
Kakovost življenja smo ocenili s splošnim vprašalnikom v kratki obliki s 36 izjavami glede medicinskih izidov (SF-36), 
in za bolezen specifičnim vprašalnikom o ortognatski kakovosti življenja (OQLQ). 
Rezultati: Pri povprečnih vrednostih rezultatov vprašalnika OQLQ je med ortodontskimi in ortognatskimi pacienti 
prišlo do pomembnih razlik. Pacienti, predvideni za ortodonsko zdravljenje, so imeli v primerjavi s pacienti, 
predvidenimi za ortognatsko zdravljenje, statistično pomembno nižje rezultate pri vseh elementih vprašalnika OQLQ, 
razen pri zavedanju obrazne deformacije.  Pokazale so se statistično pomembne korelacije (p < 0,05) med rezultati 
OQLQ ter naslednjimi demografskimi in kliničnimi spremenljivkami: spol, starost, resnost malokluzije, sagitalni 
položaj maksile in mandibule, vertikalni položaj maksile, položaj spodnjih sekalcev, intermaksilarni kot, rezultati 
po Beckovi lestvici depresivnosti in Beckovi lestvici tesnobe. Neodvisni prediktorji za načrtovanje ortodontskega in 
ortognatskega zdravljenja pri pacientih z malokluzijo so bili dva elementa vprašalnika OQLQ – obrazna estetika in 
zavedanje obrazne deformacije, ter skupni rezultat OQLQ, in sicer po prilagoditvi glede na demografske značilnosti, 
skeletne parametre, tesnobo in depresijo. 
Sklep: Naše ugotovitve kažejo, da je bila kakovost življenja pri pacientih, predvidenih za ortodontsko zdravljenje, 
glede na rezultate OQLQ boljša kot pri pacientih, predvidenih za ortognatsko zdravljenje.

1 INTRODUCTION 
Malocclusion is a multifactorial dentofacial disorder 
which occurs in the majority of persons in population (1). 
Although it is not considered a disease, malocclusion can 
significantly affect orofacial aesthetics, oral functions and 
oral health (2). Disturbed aesthetics and function in this 
region can lead to psychological and social problems and, 
particularly in the domain of psychosocial adaptation, may 
potentially have an adverse effect on quality of life (3).
Despite Angle’s widely accepted qualitative classification 
of malocclusion (4), quantitative occlusal indices such as 
the Index of Orthodontic Treatment Need (IOTN) (5) and 
the Peer Assessment Rating Index (PAR index) (6) were 
created in order to provide easy, uniform and reproducible 
malocclusion recordings. Those qualitative and quantitative 
objective measures are important for malocclusion 
diagnostic procedures, therapeutic decisions and 
malocclusion epidemiology. However, when considering the 
necessity of orthodontic treatment and patient treatment 
outcome satisfaction, Patient-Centred Measures (PCM) 
are also recommended (7). Additionally, Health-Related 
Quality of Life (HRQoL) and Oral Health-Related Quality 
of Life (OHRQoL) measures can give great insight into the 
impact of health, disease, care and treatment (8). Specific 
instruments sensitive enough to detect changes in the 
quality of life in persons with malocclusion have therefore 
been created; these include the Orthognathic Quality of 
Life Questionnaire (OQLQ) (9, 10) and the Malocclusion 
Impact Questionnaire (MIQ) (11-13).
Studies related to malocclusion and quality of life have 
played a significant role in scientific literature in recent 
years (14-17). It has been consistently demonstrated 
that malocclusions have harmful effects on OHRQOL, 
predominantly in the domains of emotional and social 
well-being. Additionally, the routine clinical application 
of quality of life measures in orthodontics is still limited. 
However, findings from studies on quality of life may have 
a potentially significant role in improving the quality 
of orthodontic care (3, 18). Since the quality of life 
concept is multidimensional and dynamic, many factors 
influence malocclusion-related quality of life, such as: 
the demographic, cultural and social characteristics of 
the observed population, the timing and frequency of 
measurement, and the appropriate choice of measuring 
instruments (19). Finally, additional factors that also 
influence malocclusion-related quality of life are anxiety, 
depression and self-esteem (20-22).
The objective of this study was to assess pre-treatment 
quality of life and the relevant clinical variables in adult 
patients with malocclusion in order to potentially improve 
orthodontic treatment strategies. 
2 METHODS
2.1 Study Design
This is a cross-sectional study comprising all consecutive 
patients from the Department of Orthodontics, School of 
Dental Medicine, University of Belgrade, from December 
2015 to February 2017.
2.2. Observed Population 
In this study, the group consisted of 240 participants, 
all young adults who presented consecutively at the 
Department of Orthodontics, School of Dental Medicine, 
University of Belgrade and expressed a personal desire to 
have their malocclusion corrected. 
The inclusion criteria were the presence of malocclusion, 
a personal desire for orthodontic treatment, age 17+ 
years and signed informed consent form. Patients who 
had already had orthodontic treatment, and patients 
with craniofacial deformities (e.g. cleft lip, cleft palate 
and syndromes) were excluded. Before enrolment, all the 
subjects provided signed informed consent. The study was 
approved by the Ethics Committee of the School of Dental 
Medicine, University of Belgrade (No 1/2016). 
Standard orthodontic diagnostic procedures were 
performed and diagnosis established for all participants. 
The diagnostic procedure included: interview, medical 
and dental history, clinical evaluations of oral health, jaw 
and occlusal function, facial and dental appearance, and 
an analysis of diagnostic records. 
2.3. Study Instrument
Malocclusion severity was measured using the pre-
treatment Peer Assessment Rating index (PAR index). 
This index was created for assessing the outcome of 
orthodontic treatment, and has also been used for 
assessing and recording malocclusion severity (6). More 
severe malocclusion was given a higher single PAR pre-
treatment score. In this study, the PAR index was assessed 
by one senior dentist (specialist in orthodontics) trained 
in PAR index measurement. The components of PAR index 
have to be weighted. In this study, the British weighting 
values were used. 
Skeletal malocclusion components were assessed by tracing 
and measuring angular and linear skeletal relations using 
lateral cephalometric radiographs. The manual measuring 
method was performed by a senior dentist/ specialist in 
orthodontics. In order to analyse the jaw anteroposterior 
relationship, the jaw vertical relationship, the rotation 
of the jaw bases, incisor position, type of facial growth 
and the dimension of the jaw bases, angles and linear 
parameters (anterior face height N-Me, posterior face 
height S-Go, anterior cranial base length Se-N, upper 
and lower jaw base length, mandibular corpus length and 
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mandibular ramus length) were measured and recorded. 
The cephalometric measurements were interpreted and 
the values of all skeletal measures defined in accordance 
with the average values of the corresponding parameters 
(23) (Table 1).  
Prior to discussing treatment options, participants 
completed five self-reporting Serbian versions of the 
following questionnaires: Medical Outcomes Study Short 
Form-36  (SF-36) (24), Orthognathic Quality Of Life (OQLQ) 
(9, 10, 25),  Beck Depression Inventory (BDI) (26), Beck 
Anxiety Inventory (BAI) (27), and Rosenberg Self-Esteem 
Scale (RSES) (28). Demographic and clinical data was 
collected by the investigator. 
2.4 Observed Outcome
After diagnostic procedures and detailed discussion with 
patients had been performed, all participants were 
divided in two groups in accordance with the treatment 
options: patients for whom an orthodontic treatment plan 
was considered, and patients for whom an orthognathic 
treatment plan was selected.
2.5 Explanatory Factors
The variables that were analysed as potential explanatory 
factors responsible for the variability of observed 
outcomes were the different domains of the OQLQ 
(“Social aspects of deformity”, “Facial aesthetics”, “Oral 
function”, “Awareness of facial deformity”) and the total 
OQLQ. 
Table 1. List of malocclusion skeletal parameters analysed in the study of quality of life assessment in patients with malocclusion 
undergoing orthodontic and orthognathic treatment in Serbia.
*Source: Ozerovic, 1985 (23); ANB – sagittal angle between upper and lower jaw; SNA – sagittal angle between base of skull and upper 
jaw; SNB – sagittal angle between base of skull and lower jaw; SN/SpP – vertical angle between base of skull and upper jaw; SN/MP – 
vertical angle between base of skull and lower jaw; SpP/MP – vertical angle between upper and lower jaw; Bjork – type of face growth 
according to skeletal angles; Jarebach – type of face growth according to vertical face proportions; I/SpP – sagittal inclination of upper 
incisors; i/MP – sagittal inclination of lower incisors; C max – length of maxillary base; C mand – length of mandibular base; C ram – 
length of mandibular ramus 
ANB   
(2-4)°        
SNA  
82°
SNB  
80°       
SN/SpP  
12°           
SN/MP  
32°           
SpP/MP  
20°    
Bjork  
396°       
Jarebach  
(62–65)%  
I/SpP  
(65–75)°  
i/MP  
(87–93)°  
C max  
(7/10 NSe )  
C mand  
(21/20 NSe ) 
C ram  
(5/7 Cmnd)
Stainer 
Stainer 
Stainer 
Stainer 
Stainer 
Schwarc 
Bjork 
Jarebach 
Schwarz 
Schwarc 
Schwarc 
Schwarc 
Schwarc
skeletal class III 
maxillary retrognathism 
mandibular retrognathism 
 maxillary ante inclination 
 mandibular forward rotation 
skeletal deep bite 
horizontal face growth 
vertical face growth 
↑incisors labial inclination 
↓incisors lab. inclination 
short maxillary corpus 
short mandibular corpus 
short mandibular ramus
 skeletal class I 
average  sagittal position   
         
average  sagittal position 
           
maxillary normal inclination 
mandibular neutral rotation 
normal bite 
neutral face growth 
neutral face growth 
↑incisors normal inclination 
↓incisors normal inclination 
average maxillary corpus 
average mandibular corpus 
average mandibular ramus
skeletal class II 
maxillary prognathism 
mandibular prognathism 
maxillary retro inclination 
mandibular backward rotation 
skeletal open bite 
vertical face growth 
horizontal face growth 
↑incisors oral inclination 
↓incisor oral inclination 
long maxillary corpus 
long mandibular corpus 
long mandibular ramus
Parameters* Author* <   = Average value >

2.6 Confounding Factors
Confounding factors are variables that influence both the 
dependent variable and independent variable, causing 
a false association. In our investigation, demographic 
characteristics, skeletal parameters, anxiety and depression 
were considered as potential confounding factors. 
2.7 Methods of Analysis
For the comparison of categorical variables, the χ2 test 
was used. An analysis of variance (ANOVA) was performed 
for continuous variables. Correlation analysis examined 
the relationship between two variables, and Pearson’s 
correlation test (for continuous variables) and Spearman’s 
test (for categorical variables) were used, depending on 
the data distribution. 
The predictive value of the baseline scores of the different 
domains of OQLQ (independent variables) for different 
treatment options (dependent variable: treatment – 
orthodontic or orthognathic), adjusted by demographic 
characteristics, skeletal parameters, anxiety and 
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depression, were assessed by using logistic regression 
analyses. In order to assess the reliability of the generic 
(SF-36) and specific (OQLQ) questionnaires, we performed 
additional logistic regression analyses in the same 
manner.   We used odds ratio (OR) with corresponding 95% 
confidence intervals (CI) as a measure of effect, and a 
p-value of 0.05 was considered as statistically significant. 
3 RESULTS
Out of 240 patients who met the inclusion criteria, 104 
(43.3%) were male and 136 (56.7%) female, with an average 
age of 21 years (range 17–39).
The mean pre-treatment PAR index, as a measure of 
malocclusion severity, was 32.2 ±11.68 (range 5–57). The 
majority of participants (132, 55%) had PAR index pre-
treatment values of between 30 and 49. Table 2 shows the 
mean values of malocclusion severity measured using the 
PAR index in the groups with different treatment options.
Table 2. Clinical variables in the study of quality of life assessment in patients with malocclusion undergoing orthodontic and 
orthognathic treatment in Serbia.
ANB – sagittal angle between upper and lower jaw; SNA – sagittal angle between base of skull and upper jaw; SNB – sagittal angle 
between base of skull and lower jaw; SN/SpP – vertical angle between base of skull and upper jaw; SN/MP – vertical angle between 
base of skull and lower jaw; SpP/MP – vertical angle between upper and lower jaw; Bjork – type of face growth according to skeletal 
angles; Jarebach – type of face growth according to vertical face proportions; I/SpP – sagittal inclination of upper incisors; i/MP – 
sagittal inclination of lower incisors; 
Age                                        
PAR index pre-treatment score
All                                            
Orthodontic treatment                                       
Orthognathic treatment                                        
Refused orthognathic treatment                                         Cephalometric parameters     
∠ ANB
∠ SpP/MP
∠ SNA
∠ SNB
∠ SN/SpP
∠ SN/MP
∠ I/SpP
∠ i/MP
Bjork
Jarebach
Maxillary. Corpus Length. Discrepancy
Mandibular Corpus. Length.  Discrepancy
Mandibular Ram. Length. Discrepancy.
236
240
82
92
66
230
230
230
230
230
230
231
231
229
229
230
230
230
21.0±4.4 
32.2±11.7
22.3±9.1
39.4±9.3
34.5±8.7
1°±4.60
25.52°±7.28
80.45°±4.45
79.61°±5.95
9.05°±3.40
34.48°±7.67
65.09°±8.53
95.6°±6.01
394.0°±7.97
64.7%±6.08
0.0mm±3.52
2.9mm±5.97
5.8mm±5.75
17–39
5–57
5–50
12–57
17–55
-11.0–13.0
3.0–43.0
68.0–98.0
62.0–100.0
0.0–20.0
11.5–56.0
39.0–90.0
67.0–98.9
371.0–417.0
45.0–85.0
-12.0–14.0
-35.0–18.6
-15.0–25.5
Variables n Range Mean±SD / Median±SD

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141
Table 3. Distribution of patients according to the pre-treatment values of various clinical and cephalometric parameters in the study 
of quality of life assessment in patients with malocclusion undergoing orthodontic and orthognathic treatment in Serbia.
PAR – Peer Assessment Rating Index; ANB – sagittal angle between upper and lower jaw; SNA – sagittal angle between base of skull and 
upper jaw; SNB – sagittal angle between base of skull and lower jaw; SN/SpP – vertical angle between base of skull and upper jaw; SN/
MP – vertical angle between base of skull and lower jaw; SpP/MP – vertical angle between upper and lower jaw; Bjork – type of face 
growth according to skeletal angles; Jarebach – type of face growth according to vertical face proportions; I/SpP – sagittal inclination of 
upper incisors; i/MP – sagittal inclination of lower incisors; 
PAR
n=240
∠ ANB
n=230
∠ pP/MP
n=230
∠ SNA
n=230
∠ SNB
n=230
∠ SN/SpP
n=230
∠ SN/MP
n=230
∠ I/SpP
n=230
∠ i/MP
n=230
Maxillary
corpus
length
Mandibular
ramus 
length
Mandibular
corpus 
length
Facial
growth
(0–9)
(10–29)
(30–49)
(>50)
class III skeletal malocclusion
class I skeletal malocclusion
class II skeletal malocclusion
low intermaxillary angle
average intermaxillary angle
high intermaxillary angle
maxillary retrognathism
maxillary orthognathism
maxillary prognathism 
mandibular retrognathism
mandibular orthognathism
mandibular prognathism
maxillary anteinclination
maxillary normal inclination
maxillary retroinclination
mandibular forward rotation
mandibular neutral rotation
mandibular backward rotation
upper incisors labial inclination
upper incisors normal inclination
upper incisors oral inclination
lower incisors labial inclination
lower incisors normal inclination
lower incisors oral inclination
short
normal
long
short
normal
long
short
normal
long
vertical facial growth
neutral facial growth
horizontal facial growth
7
90
132
11
126
51
53
42
68
120
124
23
83
114
19
97
176
26
28
81
16
133
129
77
25
89
34
108
87
78
64
26
20
184
47
40
142
88
39
102
  2.9%
37.5%
55.0%
  4.6%
54.8%
22.2%
23.0%
17.5%
29.6%
52.2%
53.9%
10.0%
36.1%
49.5%
8.3%
42.2%
76.5%
11.3%
12.2%
35.2%
7.0%
57.8%
55.8%
33.4%
10.8%
38.5%
14.7%
46.8%
37.9%
34.3%
27.8%
11.3%
8.7%
80.0%
20.5%
17.8%
61.7%
38.5%
17.0%
44.5%
% n
The mean values of all cephalometric variables are 
presented in Table 2 and the frequencies of various 
malocclusion skeletal variables in Table 3. Of the group 
in total, orthodontic treatment was planned for 82 
participants (34.2%) and orthognathic treatment for 158 
participants (65.8%).

An analysis of SF-36 scores showed that the Composite 
Score of Physical Functioning (85. 9±16.5) was higher than 
the Composite Score of Mental Functioning (75.7±21.8). 
The two composite scores, physical and mental 
functioning, are derived from a weighted combination 
of the scale scores. Physical Health Composite includes 
Physical Functioning, Role Physical, Bodily Pain and 
General Health scale scores. Mental Health Composite 
comprises Vitality, Social Functioning, Role Emotional, 
and Mental Health scale scores. The worst score was for 
the domain of Vitality (66.5±21.1), and the highest score 
and the best quality of life was noticed in the domain of 
Physical Functioning (94.8±15.5) (Figure 1). Quality of life 
was subsequently assessed using OQLQ, which showed the 
highest mean score in the domain of the “Social aspects 
of deformity”, and the lowest score in the domain of 
“Awareness of deformity” (Figure 2).
10.2478/sjph-2020-0018 Zdr Varst. 2020;59(3):137-145
142
Figure 1.
Figure 2.
Domain, composite and total scores of SF-36 
questionnaire.
Domain and total scores of OQLQ questionnaire.
BDI scores showed that of the 240 participants, eight 
(3.3%) had moderate symptoms of depression and only two 
(0.8%) had severe depression. The mean BDI score in our 
group was 5.0±6.9 (range 0–63). The BAI scores showed 
that 75% participants did not have symptoms of anxiety. 
Moderate and severe anxiety was detected in the same 
proportion of patients (12.5%). The mean value of the BAI 
score in the cohort was 6.2±7.7 (range 0–41). The level of 
self-esteem as measured by the Rosenberg scale showed a 
mean value of 28.3±6.3 (range 0–39).
Table 4 presents the results of the correlation analyses 
between the OQLQ domain score and the different 
demographic and clinical variables. Statistically significant 
positive correlations were demonstrated between 
all OQLQ domains scores and total score and gender 
and malocclusion severity. Additionally, a statistically 
significant positive correlation (p<0.01) was detected 
between all OQLQ domains and total scores and BDI and 
BAI, and OQLQ. 
Table 4. Correlation analyses between OQLQ scores and clinical variables in the study of quality of life assessment in patients with 
malocclusion undergoing orthodontic and orthognathic treatment in Serbia. 
Social aspects 
of deformity
Facial  
aesthetics
Oral  
function
Awareness of 
facial deformity
Total
0.135 
0.037
0.232 
0.001
0.189 
0.003
0.236 
0.001
0.236 
0.001
ρ 
p
ρ 
p
ρ 
p
ρ 
p
ρ 
p
r 
p
r 
P
r 
p
r 
p
r 
P
-0.142 
0.105
-0.14 
10.033
-0.009 
0.898
-0.226 
0.001
-0.146 
0.027
-0.142    
0.032
-0.116    
0.078
-0.080    
0.226
-0.083    
0.211
-0.129    
0.050
-0.144    
0.029
-0.069    
0.301
-0.059    
0.377
-0.104    
0.115
-0.124    
0.061
-0.168 
0.011
-0.084 
0.205
-0.039 
0.554
-0.127 
0.055
-0.142 
0.031
0.028 
0.668
0.029 
0.028
0.138 
0.037
-0.123 
0.062
0.023 
0.723
0.174 
0.007
0.251 
0.001
0.218 
0.001
0.100 
0.122
0.125 
0.001
0.235 
0.001
0.142 
0.028
0.142 
0.028
-0.006 
0.925
0.179 
0.005
-0.083 
0.204
-0.026 
0.688
0.158 
0.015
-0.063 
0.335
-0.22 
0.739
0.401 
0.001
0.371 
0.001
0.238 
0.001
0.376 
0.001
0.434 
0.001
0.305 
0.001
0.288 
0.001
0.207 
0.001
0.391 
0.001
0.363 
0.001
OQLQ 
domains
Gender Sagittal
maxillary 
position
Sagittal
mandibular 
position
Maxillary 
rotation
B angle Lower
incisor
inclination
Thera- 
peutic 
option
PAR
score
Age BDI
score
BAI
score

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According to the findings presented in Table 5, a 
statistically significant difference between the different 
treatment options was detected for the total OQLQ 
score and all its domains, except for the “Awareness of 
facial deformity” domain. Patients for whom orthodontic 
treatment was planned had statistically significantly lower 
scores in comparison to those for whom orthognathic 
treatment was planned. This was the case in all OQLQ 
domains except for “Awareness of facial deformity”. There 
was no statistically significant difference in mean OQLQ 
domains and total score between the orthognathic group 
and those who had been refused orthognathic treatment 
(data not shown).
Table 5.
Table 6.
OQLQ scores according to the various treatment 
options in the study of quality of life assessment in 
patients with malocclusion undergoing orthodontic 
and orthognathic treatment in Serbia.
Predictive value of OQLQ domains for two different 
treatment options in the study of quality of life 
assessment in patients with malocclusion undergoing 
orthodontic and orthognathic treatment in Serbia.
*Adjusted for demographic characteristics, skeletal parameters, 
anxiety and depression
Social aspects 
of deformity
Facial 
aesthetics
Oral function
Awareness of 
facial deformity
Total
Social aspects 
of deformity
Facial 
aesthetics
Oral function
Awareness of 
facial deformity
Total OQLQ
10.6±9.8 
9.7±6.1 
6.2±4.9
6.7±4.8 
33.9±21.3
1.00–1.14 
1.03–1.28 
0.97–1.21
1.03–1.32 
1.00–1.07
6.5±7.7 
6.6±5.1 
4.7±4.7
6.1±4.8 
23.9±18.0
1.07 
1.15 
1.08
1.14 
1.04
0.001 
<0.001 
0.003
0.360 
<0.001
0.051 
0.013 
0.160
0.046 
0.020
p
p
Orthognathic 
treatment
95%CI 
mean value  
± SD
Orthodontic 
treatment
OR*
mean value  
± SD
OQLQ 
domains  
OQLQ domains  
According to the results presented in Table 6, the 
independent predictors for the planning of orthodontic 
and orthognathic treatment in patients with malocclusion 
were two OQLQ domains, “Facial aesthetics” and 
“Awareness of facial deformity”, as well as total OQLQ 
score, after adjustment for demographic characteristics, 
skeletal parameters, anxiety and depression. The same 
analyses were performed for the SF-36 domains. None was 
found to be predictive (data not shown).   
4 DISCUSSION
This study demonstrates the existence of significant 
differences in the mean values of all OQLQ domain 
scores between orthodontic and orthognathic patients, 
except in the domain of “Awareness for facial deformity”. 
Patients for whom orthodontic treatment was planned had 
statistically significantly lower baseline OQLQ scores in 
comparison to those for whom orthognathic treatment was 
planned, suggesting that they enjoyed a better quality of 
life. On the other hand, there was no significant difference 
in mean OQLQ domain scores and total score between the 
orthognathic group of patients and those who had been 
refused orthognathic treatment. Additionally, independent 
predictors for the planning of orthodontic and orthognathic 
treatment in patients with malocclusion were two OQLQ 
domains, “Facial aesthetics” and “Awareness of facial 
deformity”, as well as total OQLQ score. 
The mean values for all OQLQ domains in the total cohort of 
our patients with malocclusion were lower than in previously 
published studies (10, 29-31). The data varies because of 
differences in study protocols and settings. Our findings 
are otherwise similar to those obtained in Cunningham’s 
study (10), but different to those in the study conducted 
by Bock et al. (30). While German patients’ complaints 
focused heavily on “Functional impairment” (30), those of 
Serbian patients focused on “Facial aesthetics”. Tajima et 
al. showed OQLQ domain scores for three different groups 
in a Japanese population (orthodontic group, orthognathic 
group, control group with normal occlusion). All those 
people focused their complaints on facial aesthetics in 
first place and on the social aspects of deformity in second 
place (29). These authors also showed similar results to ours 
in relation to the comparison between surgically treated 
and non-treated patients, namely a significant difference 
in OQLQ domain scores between these two groups (29). 

10.2478/sjph-2020-0018 Zdr Varst. 2020;59(3):137-145
144
Results comparing quality of life before orthodontic and 
orthognathic treatment in patients with malocclusion are 
inconsistent (31-33). In the two recent studies referred to 
above (32, 33), quality of life was better or the same in the 
orthodontic treatment first group in comparison with the 
surgery first group. More recently, however, the contrary 
has been shown: in a group of 32 patients, those patients 
planned for surgery first had a lower total OQLQ score and 
social domain score than those planned for orthodontics 
first (31). 
In order to assess the reliability of the generic (SF-36) and 
specific (OQLQ) instruments in detecting differences in 
quality of life and when planning different therapeutic 
strategies for patients with malocclusion, we performed 
two independent logistic regression analyses. None of the 
SF-36 domains were found to be predictive. On the other 
hand, we demonstrated that OQLQ was more reliable and 
sensitive for the detection of differences in quality of 
life between different treatment options. Furthermore, 
it has to be mentioned that statistically significant 
correlations between SF-36 and PAR pre-treatment scores 
were not found, suggesting that malocclusion presence 
and severity did not influence general health-related 
QoL in our cohort. However, the correlation of OQLQ 
and PAR pre-treatment scores indicated that participants 
with more severe malocclusion had worse specific QoL, 
which accords with the notions presented by Sun et al. 
(34). In our survey, there was no statistically significant 
correlation with malocclusion severity, except with the 
domain of “Awareness of facial deformity”. Similar results 
are shown in the study by Struggle et al. (35). 
A statistically significant correlation between sagittal 
type of malocclusion and OQLQ scores was not found in 
our patients. Regarding intermaxillary angle, patients 
with low angle malocclusion presented with the most 
significantly impaired specific QoL, especially in “Social 
aspects of deformity”. Finally, in our cohort malocclusion 
severity had greater impact on malocclusion-specific QoL 
than the skeletal type of malocclusion, which is similar 
to the results obtained by Rusnan et al. in the Finnish 
population (36). We have also demonstrated that the 
domain of “Awareness of facial deformity” correlated 
significantly with maxillary retrognathism. Likewise, the 
domain of “Facial aesthetics” score correlated with both 
maxillary and mandibular retrognathism, suggesting that 
middle face concavity or a possible bird-like profile might 
be less acceptable in our population.
Some limitations of the present study need to be kept 
in mind when interpreting the results. First, the choice 
of the questionnaire could be discussed. The Oral 
Health Impact Profile (OHIP) instrument is a widely used 
generic questionnaire for oral health quality of life (37). 
However, this questionnaire has unfortunately not yet 
been validated for Serbian cultural settlements. Another 
limitation is related to the design of the study, which was 
cross-sectional. A longitudinal study capable of following 
the evolution of quality of life after treatment would have 
been preferable. Quality of life has therefore recently 
been assessed using OQLQ in two groups of patients with 
dentofacial deformities after the orthodontic-first and 
orthognathic-first approach in 32 patients. It was shown 
that the mean OQLQ score and the individual domain 
scores showed significant improvements at six weeks and 
six months post-operatively (31). The strength of our study 
might be in the rather high number of study participants 
treated and followed-up at the national referral centre.     
We should emphasise that the number of adult patients 
seeking orthodontic care today is on the rise and that 
clinicians frequently face difficulties in achieving adequate 
therapeutic strategies, since in the majority of these cases 
both surgical and non-surgical treatment plans can be 
considered. In cases of significant skeletal malocclusion, 
the chance that orthodontic treatment alone (i.e. without 
surgery) will produce beneficial effects is small. However, 
especially in borderline cases, it would be crucial to define 
whether the difference in quality of life after intervention 
between surgical and non-surgical treatment is expected 
to be significant. Moreover, future studies that deal with 
quality of life changes after surgical or non-surgical 
treatment first could potentially provide data on predictive 
factors of treatment outcome. Finally, such quality of life 
data might be of interest to public oral health systems, as 
well as to health insurance companies and national health 
services, as one of the outcome measures.   
In conclusion, our patients for whom orthodontic 
treatment was planned demonstrated better quality of 
life according to their OQLQ scores than those planned 
for whom an orthognathic strategy was planned. The 
independent predictors for the planning of orthodontic and 
orthognathic treatment in patients with malocclusion were 
two OQLQ domains, “Facial aesthetics” and “Awareness of 
facial deformity”. All patients with malocclusion should 
be involved in the shared decision-making process related 
to the choice of treatment, after a detailed diagnostic 
procedure followed by a quality of life assessment using 
specific instruments. This could have a significant impact 
on the treatment strategy, at least in certain cases.
CONFLICT OF INTEREST
The authors declare that no conflicts of interest exist.
FUNDING
This study was supported by the Ministry of Education, 
Science and Technological Development of the Republic 
of Serbia (Grant nos 175031 and 175087). 
 

10.2478/sjph-2020-0018 Zdr Varst. 2020;59(3):137-145
145
ETHICAL APPROVAL
Received from the Ethical Committee of the Faculty of 
Dental Medicine of the University of Belgrade.
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