Evaluation of Effects of Clear Aligners vs Fixed Appliances on Oral Health Related Quality of Life During Orthodontic Treatment: A Prospective Study

Abstract

Background:

Orthodontic treatment is often associated with discomfort, esthetic concerns, and functional limitations, all of which can impact oral health-related quality of life (OHRQoL). Clear aligners have emerged as a more esthetic and comfortable alternative to traditional fixed appliances.

Methods:

A total of 80 participants (mean age: 21.6 ± 3.4 years) undergoing orthodontic treatment were recruited and divided equally into two groups: Group A (clear aligners) and Group B (fixed appliances). OHRQoL was assessed using the Oral Health Impact Profile-14 (OHIP-14) questionnaire at baseline (T0), 3 months (T1), and 6 months (T2). Statistical analyses included paired and unpaired t-tests and repeated-measures ANOVA.

Results:

Both groups showed an initial decline in OHRQoL after appliance placement. However, Group A demonstrated significantly better scores in physical pain (T1: 3.1 ± 1.0 vs 5.4 ± 1.3, P < 0.001), psychological discomfort (T2: 2.6 ± 0.9 vs 4.8 ± 1.5, P = 0.002), and social disability (T2: 1.9 ± 0.6 vs 3.5 ± 1.1, P = 0.004) compared to Group B. By 6 months, the aligner group showed significant recovery in OHRQoL domains, whereas fixed appliance users continued to experience moderate impact.

Conclusion:

Clear aligners are associated with a more favorable OHRQoL during orthodontic treatment compared to fixed appliances, particularly in reducing pain, psychological stress, and social challenges.

INTRODUCTION

Orthodontic treatment aims to improve dentofacial aesthetics, occlusal function, and oral health. However, the process itself can negatively affect patients’ oral health-related quality of life (OHRQoL), primarily due to discomfort, dietary restrictions, speech impediments, and social or psychological impact.[1] The concept of OHRQoL is increasingly being recognized as a critical outcome measure in orthodontic research, reflecting not only clinical success but also patient-centered care.[2]

Fixed orthodontic appliances (brackets and wires) have long been the standard of care but are associated with common challenges including mucosal irritation, hygiene difficulties, and pain during activation.[3] By contrast, clear aligners offer improved aesthetics, removability for oral hygiene, and greater comfort, potentially translating to improved OHRQoL.[4]

Recent studies have evaluated the subjective experience of patients undergoing different orthodontic modalities, showing mixed results. While some have highlighted better psychosocial outcomes with aligners, others found no significant differences in long-term quality of life.[5,6] Furthermore, the impact of appliance type on specific domains such as physical pain, psychological discomfort, and social functioning during treatment has not been adequately addressed in prospective designs.

This study aims to fill this gap by prospectively evaluating and comparing the effects of clear aligners and fixed orthodontic appliances on OHRQoL during treatment using the validated OHIP-14 questionnaire.

MATERIALS AND METHODS

Study design and participants

A prospective, longitudinal study was conducted in the Department of Orthodontics, enrolling 80 patients aged 18–30 years indicated for mild to moderate malocclusion correction. Patients were recruited between January and July 2024 and were followed for 6 months post-treatment initiation.

Inclusion criteria

• Age 18–30 years.

• Class I malocclusion with crowding or spacing ≤5 mm.

• No history of orthodontic treatment.

• Good general and oral health.

Exclusion criteria

• Systemic illnesses or craniofacial syndromes.

• Periodontal disease or untreated caries.

• Need for orthognathic surgery.

• Poor compliance or refusal to participate.

Group allocation

Patients were randomly assigned into two equal groups (n = 40 each):

• Group A: Treated with clear aligners (Invisalign®).

• Group B: Treated with fixed metal appliances (0.022” MBT system).

OHRQoL assessment tool

The Oral Health Impact Profile-14 (OHIP-14) was administered at T0 (baseline), T1 (3 months), and T2 (6 months). The questionnaire includes seven domains: functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap.

Data collection and statistical analysis

Responses were scored on a 5-point Likert scale (0–4), with higher scores indicating greater negative impact. Data were analyzed using SPSS v25. Paired and unpaired t-tests assessed intragroup and intergroup differences. Repeated-measures ANOVA evaluated changes over time, with significance set at P < 0.05.

RESULTS

Participant demographics

The final sample included 78 participants (2 dropouts from Group B). The mean age was 21.6 ± 3.4 years in Group A and 22.1 ± 3.1 years in Group B, with no significant baseline differences (P = 0.43).

OHIP-14 total scores

At T1, Group A showed a moderate increase in OHIP-14 scores (mean: 12.4 ± 3.6) compared with baseline (8.2 ± 2.8, P < 0.01), while Group B showed a more marked increase (mean: 18.9 ± 4.2 vs 8.4 ± 2.5, P < 0.001). At T2, scores improved in both groups but remained significantly higher in Group B [Table 1].

Table 1.

Comparison of OHIP-14 total scores between groups

Time Point		Group A (Clear Aligners)		Group B (Fixed Appliances)		P
Baseline		8.2±2.8		8.4±2.5		0.68
3 Months		12.4±3.6		18.9±4.2		<0.001
6 Months		9.1±3.1		14.7±3.9		<0.001

Domain-specific comparisons

At T1 and T2, Group A consistently reported lower scores in physical pain, psychological discomfort, and social disability compared to Group B [Table 2]. Functional limitation and physical disability did not differ significantly.

Table 2.

Domain-specific OHIP-14 score comparison at 6 months

Domain		Group A (Mean±SD)		Group B (Mean±SD)		P
Physical Pain		2.5±0.8		4.7±1.2		<0.001
Psychological Discomfort		2.6±0.9		4.8±1.5		0.002
Social Disability		1.9±0.6		3.5±1.1		0.004

DISCUSSION

This study evaluated the comparative impact of clear aligners and fixed appliances on oral health-related quality of life during active orthodontic treatment. Our findings indicate that patients undergoing treatment with clear aligners experienced significantly less impairment in multiple domains of OHRQoL, particularly in pain, psychological well-being, and social functioning.

These findings align with previous studies which reported lower discomfort and better psychosocial adaptation in aligner users.[7,8] Nguyen et al.[9] showed that clear aligners were associated with less pain and speech difficulty in the early treatment phase. Similarly, Moshkelgosha et al.[10] observed better patient-reported quality of life in clear aligner users over a 6-month period.

Fixed appliances, by contrast, can cause continuous mucosal irritation, dietary constraints, and oral hygiene challenges that potentially exacerbate discomfort and social embarrassment.[11] Although OHRQoL improved over time in both groups, recovery was faster and more complete in the aligner group, suggesting a long-term benefit.

One limitation of this study is its reliance on subjective self-reporting. Future studies integrating objective clinical measures and long-term outcomes may yield deeper insights. Nevertheless, this study contributes to growing evidence supporting the patient-centered advantages of clear aligners.

CONCLUSION

This prospective study demonstrates that clear aligners have a significantly more favorable impact on oral health-related quality of life compared to fixed appliances during the course of orthodontic treatment. Reduced pain, better psychological comfort, and lower social distress were observed in the aligner group. These findings support the integration of patient-reported outcomes into orthodontic appliance selection, particularly for adult and esthetically conscious patients.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.