Quality of Life Assessment in Patients with Malocclusion Undergoing Orthodontic and Orthognathic Treatment
Article Category: Original scientific article
Published Online: Jun 25, 2020
Page range: 137 - 145
Received: Jul 05, 2019
Accepted: May 05, 2020
DOI: https://doi.org/10.2478/sjph-2020-0018
Keywords
© 2020 Ljiljana Vučić et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.
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, 12, 13).
Studies related to malocclusion and quality of life have played a significant role in scientific literature in recent years (14, 15, 16, 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, 21, 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.
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.
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.
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 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).
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.
| Stainer | skeletal class III | skeletal class I | skeletal class II | |
| Stainer | maxillary retrognathism | average sagittal position | maxillary prognathism | |
| Stainer | mandibular retrognathism | average sagittal position | mandibular prognathism | |
| Stainer | maxillary ante inclination | maxillary normal inclination | maxillary retro inclination | |
| Stainer | mandibular forward rotation | mandibular neutral rotation | mandibular backward rotation | |
| Schwarc | skeletal deep bite | normal bite | skeletal open bite | |
| Bjork | horizontal face growth | neutral face growth | vertical face growth | |
| Jarebach | vertical face growth | neutral face growth | horizontal face growth | |
| Schwarz | ↑incisors labial inclination | ↑incisors normal inclination | ↑incisors oral inclination | |
| Schwarc | ↓incisors lab. inclination | ↓incisors normal inclination | ↓incisor oral inclination | |
| Schwarc | short maxillary corpus | average maxillary corpus | long maxillary corpus | |
| Schwarc | short mandibular corpus | average mandibular corpus | long mandibular corpus | |
| Schwarc | short mandibular ramus | average mandibular ramus | long mandibular ramus |
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
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.
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.
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.
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.
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 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.
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.
Clinical variables in the study of quality of life assessment in patients with malocclusion undergoing orthodontic and orthognathic treatment in Serbia.
| 236 | 21.0±4.4 | 17–39 | |
| All | 240 | 32.2±11.7 | 5–57 |
| Orthodontic treatment | 82 | 22.3±9.1 | 5–50 |
| Orthognathic treatment | 92 | 39.4±9.3 | 12–57 |
| Refused orthognathic treatment | 66 | 34.5±8.7 | 17–55 |
| ∠ ANB | 230 | 1°±4.60 | −11.0–13.0 |
| ∠ SpP/MP | 230 | 25.52°±7.28 | 3.0–43.0 |
| ∠ SNA | 230 | 80.45°±4.45 | 68.0–98.0 |
| ∠ SNB | 230 | 79.61°±5.95 | 62.0–100.0 |
| ∠ SN/SpP | 230 | 9.05°±3.40 | 0.0–20.0 |
| ∠ SN/MP | 230 | 34.48°±7.67 | 11.5–56.0 |
| ∠ I/SpP | 231 | 65.09°±8.53 | 39.0–90.0 |
| ∠ i/MP | 231 | 95.6°±6.01 | 67.0–98.9 |
| Bjork | 229 | 394.0°±7.97 | 371.0–417.0 |
| Jarebach | 229 | 64.7%±6.08 | 45.0–85.0 |
| Maxillary. Corpus Length. Discrepancy | 230 | 0.0mm±3.52 | −12.0–14.0 |
| Mandibular Corpus. Length. Discrepancy | 230 | 2.9mm±5.97 | −35.0–18.6 |
| Mandibular Ram. Length. Discrepancy. | 230 | 5.8mm±5.75 | −15.0–25.5 |
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;
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%).
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.
| (0–9) | 7 | 2.9% | |
| (10–29) | 90 | 37.5% | |
| (30–49) | 132 | 55.0% | |
| (>50) | 11 | 4.6% | |
| ∠ | class III skeletal malocclusion | 126 | 54.8% |
| class I skeletal malocclusion | 51 | 22.2% | |
| class II skeletal malocclusion | 53 | 23.0% | |
| ∠ | low intermaxillary angle | 42 | 17.5% |
| average intermaxillary angle | 68 | 29.6% | |
| high intermaxillary angle | 120 | 52.2% | |
| ∠ | maxillary retrognathism | 124 | 53.9% |
| maxillary orthognathism | 23 | 10.0% | |
| maxillary prognathism | 83 | 36.1% | |
| ∠ | mandibular retrognathism | 114 | 49.5% |
| mandibular orthognathism | 19 | 8.3% | |
| mandibular prognathism | 97 | 42.2% | |
| ∠ | maxillary anteinclination | 176 | 76.5% |
| maxillary normal inclination | 26 | 11.3% | |
| maxillary retroinclination | 28 | 12.2% | |
| ∠ | mandibular forward rotation | 81 | 35.2% |
| mandibular neutral rotation | 16 | 7.0% | |
| mandibular backward rotation | 133 | 57.8% | |
| ∠ | upper incisors labial inclination | 129 | 55.8% |
| upper incisors normal inclination | 77 | 33.4% | |
| upper incisors oral inclination | 25 | 10.8% | |
| ∠ | lower incisors labial inclination | 89 | 38.5% |
| lower incisors normal inclination | 34 | 14.7% | |
| lower incisors oral inclination | 108 | 46.8% | |
| short | 87 | 37.9% | |
| normal | 78 | 34.3% | |
| long | 64 | 27.8% | |
| short | 47 | 20.5% | |
| normal | 40 | 17.8% | |
| long | 142 | 61.7% | |
| short | 26 | 11.3% | |
| normal | 20 | 8.7% | |
| long | 184 | 80.0% | |
| vertical facial growth | 88 | 38.5% | |
| neutral facial growth | 39 | 17.0% | |
| horizontal facial growth | 102 | 44.5% | |
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;
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).
Figure 1
Domain, composite and total scores of SF-36 questionnaire.
Figure 2
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.
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.
| ρ | 0.135 | −0.142 | −0.142 | −0.144 | −0.168 | 0.028 | 0.174 | r | 0.235 | −0.083 | 0.401 | 0.305 | |
| p | 0.105 | 0.668 | p | 0.204 | |||||||||
| ρ | 0.232 | −0.14 | −0.116 | −0.069 | −0.084 | 0.029 | 0.251 | r | 0.142 | −0.026 | 0.371 | 0.288 | |
| p | 0.078 | 0.301 | 0.205 | 0.028 | P | 0.688 | |||||||
| ρ | 0.189 | −0.009 | −0.080 | −0.059 | −0.039 | 0.138 | 0.218 | r | 0.142 | 0.158 | 0.238 | 0.207 | |
| p | 0.898 | 0.226 | 0.377 | 0.554 | p | ||||||||
| ρ | 0.236 | −0.226 | −0.083 | −0.104 | −0.127 | −0.123 | 0.100 | r | −0.006 | −0.063 | 0.376 | 0.391 | |
| p | 0.211 | 0.115 | 0.055 | 0.062 | 0.122 | p | 0.925 | 0.335 | |||||
| ρ | 0.236 | −0.146 | −0.129 | −0.124 | −0.142 | 0.023 | 0.125 | r | 0.179 | −0.22 | 0.434 | 0.363 | |
| p | 0.050 | 0.061 | 0.723 | P | 0.739 |
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).
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.
| 6.5±7.7 | 10.6±9.8 | ||
| 6.6±5.1 | 9.7±6.1 | ||
| 4.7±4.7 | 6.2±4.9 | ||
| 6.1±4.8 | 6.7±4.8 | ||
| 23.9±18.0 | 33.9±21.3 | ||
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).
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.
| 1.07 | 1.00–1.14 | 0.051 | |
| 1.15 | 1.03–1.28 | ||
| 1.08 | 0.97–1.21 | 0.160 | |
| 1.14 | 1.03–1.32 | ||
| 1.04 | 1.00–1.07 |
Adjusted for demographic characteristics, skeletal parameters, anxiety and depression
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, 30, 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).
Results comparing quality of life before orthodontic and orthognathic treatment in patients with malocclusion are inconsistent (31, 32, 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.