Annali di Stomatologia | 2026; 17(2): 293-300

ISSN 1971-1441 | DOI: 10.59987/ads/2026.2.293-300

Articles

Effect of myofunctional therapy associated with rapid palatal expansion on the restoration of nasal breathing in pediatric patients

Ernesto Buonanno¹, Jorida Jubani², Marco Schirripa¹, Francesca Russo³, Mario Palermiti¹, Elisabetta Carli⁴

¹Department of Life, Health & Environmental Sciences, Postgraduate School of Orthodontics, University of L’Aquila, L’Aquila, Italy

²Department of Life, Health & Environmental Sciences, University of L’Aquila, L’Aquila, Italy

³Department of Life, Health & Environmental Sciences, University of L’Aquila, L’Aquila, Italy

⁴Department of Surgical, Medical and Molecular Pathology and Critical Area, Dental Clinic, University of Pisa, Pisa, Italy

^*Corresponding author: Ernesto Buonanno - ernesto.buonanno.eb@gmail.com

Article History

Received: April 28, 2026

Accepted: June 20, 2026

Published: June 30, 2026

Abstract

Background

Transverse maxillary deficiency in pediatric patients is often linked to chronic oral breathing and dysfunctional neuromuscular patterns, such as low tongue posture. Rapid Palatal Expansion (RPE) corrects skeletal discrepancies, but structural expansion alone may not suffice to restore physiological nasal breathing if behavioral habits persist [1].

Objective

To evaluate the effectiveness of RPE alone compared to RPE combined with myofunctional therapy (MFT) in restoring nasal breathing in pediatric subjects.

Materials and Methods

Forty patients (8–12 years) with maxillary deficiency and oral breathing were divided into two groups: Group 1 (n=20) received RPE only; Group 2 (n=20) received RPE plus a 4-month MFT program [2]. Evaluations were performed at T0 and 6 months post-initiation (T1) using the Glatzel mirror test and clinical scoring for bruxism, nocturnal movements, drooling, and lip incompetence [3,4].

Results

At T1, Group 2 showed significantly superior outcomes across all parameters (p < 0.001). Symmetrical nasal airflow was achieved in 90% of Group 2 subjects, compared with 60% in Group 1. Furthermore, the prevalence of oral breathing dropped to 10% in the combined therapy group, compared to 40% in the RPE-only group.

Conclusions

Integrating myofunctional therapy with RPE is significantly more effective than structural correction alone for restoring nasal breathing. This multidisciplinary approach addresses both anatomical deficiencies and underlying dysfunctional habits, ensuring more stable clinical outcomes in pediatric orthodontics.

Keywords: Rapid Palatal Expansion; Myofunctional Therapy; Oral Breathing; Pediatric Orthodontics; Nasal Airway; Speech Therapy.

1. Introduction

Oral breathing is a common condition in pediatric patients and is frequently associated with functional and structural alterations of the craniofacial complex. It may originate from upper airway obstruction, such as adenoid hypertrophy, allergic rhinitis, or nasal septum deviation. Still, it can also persist as a learned dysfunctional habit even after the removal of the initial cause. If not properly addressed, oral breathing can negatively influence craniofacial growth and development.

From an orthodontic perspective, chronic oral breathing is strongly associated with transverse maxillary deficiency, posterior crossbite, high-arched palate, and altered vertical growth patterns. The imbalance between orofacial muscles, particularly reduced tongue pressure against the palate and increased activity of perioral muscles, contributes to the development and maintenance of these skeletal discrepancies [2].

Rapid Palatal Expansion (RPE) is a well-established orthopedic procedure used to correct maxillary transverse deficiency [1]. By opening the midpalatal suture, RPE increases the transverse dimension of the maxilla and, consequently, the volume of the nasal cavity [1]. Several studies have demonstrated that RPE can reduce nasal airway resistance and improve nasal airflow [3]. However, despite these anatomical improvements, the restoration of physiological nasal breathing is not always achieved [5]. One of the main limitations of RPE is that it primarily addresses structural factors without directly modifying neuromuscular function [6]. Patients with long-standing oral breathing habits often maintain dysfunctional patterns even after the expansion of the maxilla [7]. This suggests that structural correction alone is insufficient to ensure a stable functional outcome [8].

Myofunctional therapy has increasingly been recognized as a key component of the multidisciplinary management of oral breathing [5]. This therapeutic approach focuses on the re-education of orofacial muscles, aiming to restore proper tongue posture, achieve lip competence, and promote nasal breathing [6]. By targeting neuromuscular patterns, myofunctional therapy can facilitate the transition from oral to nasal breathing and enhance the stability of orthodontic results [2]. The timing of myofunctional intervention appears to be particularly relevant [2]. Initiating therapy before orthodontic treatment may improve patient awareness and neuromuscular control, preparing the functional environment for structural changes [9]. Continuing therapy during and after RPE may further support the adaptation process and prevent relapse [10]. Despite growing interest in combined approaches, clinical evidence remains limited regarding the effectiveness of myofunctional therapy when integrated with RPE, particularly when initiated before expansion [11]. Therefore, this study aims to compare the outcomes of RPE alone with those of RPE combined with a structured myofunctional therapy protocol starting one month before expansion and continuing for three months after treatment.

2. Materials and Methods

Study Design and Patient Selection

The present research was conducted as a prospective, controlled clinical study to determine whether integrating myofunctional therapy (MT) with rapid palatal expansion (RPE) yields superior results in restoring physiological nasal breathing compared with RPE alone. The study cohort consisted of 40 pediatric patients aged 8 to 12 years, recruited from a private orthodontic practice. To ensure a rigorous comparison, participants were divided into two balanced groups: Group 1 (n = 20), which received only the RPE treatment, and Group 2 (n = 20), which underwent a combined protocol of RPE and myofunctional therapy. The two groups were carefully matched at baseline for age, sex distribution, and clinical characteristics.

Inclusion and Exclusion Criteria

Eligibility for the study required a chronic oral breathing habit and a transverse maxillary deficiency necessitating expansion, often characterized by a narrow or high-arched palate [12]. Additionally, patients were required to exhibit at least one associated clinical sign, such as bruxism, nocturnal movements, drooling during sleep, or lip incompetence. Conversely, patients were excluded if they presented with severe airway obstructions requiring surgical intervention, had a history of previous orthodontic treatment, or suffered from systemic or neuromuscular disorders [13]. Poor compliance with therapy or follow-up appointments also served as grounds for exclusion.

Orthodontic and Myofunctional Protocols

All 40 participants were treated with a tooth-borne palatal expander. The activation protocol involved 0.25 mm turns performed twice daily until the targeted transverse expansion was achieved, followed by a retention period in accordance with standard clinical guidelines [14]. For patients in Group 2, a certified speech therapist administered a structured myofunctional protocol lasting approximately four months. This intervention was divided into three distinct phases. The pre-expansion phase (one month) focused on patient education, nasal breathing training, lip seal exercises, and initial awareness of tongue posture. During the active expansion phase, the focus shifted to maintaining nasal breathing patterns, performing adaptation exercises for tongue posture despite the presence of the appliance, and improving tongue mobility and swallowing coordination. Finally, the post-expansion phase (three months) was dedicated to stabilizing the palatal rest position of the tongue, reinforcing lip competence, re-educating physiological swallowing, and eliminating any residual dysfunctional habits. Compliance in this group was ensured through weekly or biweekly monitoring sessions. The clinical sequence is shown in Figure 1.

**Figure 1.** An upper occlusal photograph of a patient who has undergone orthodontic and myofunctional treatment.

Clinical Evaluation and Outcome Measures

Comprehensive clinical evaluations were performed at two time points: baseline (T0) and 6 months after treatment initiation (T1). To minimize inter-examiner variability, a single clinician performed all assessments. The evaluation toolkit included the Glatzel mirror test for the qualitative analysis of nasal airflow intensity and symmetry, as well as a clinical assessment of daytime and nocturnal oral breathing, bruxism, nocturnal movements, drooling, and lip incompetence. The primary outcome was defined as the complete restoration of nasal breathing. Secondary outcomes included reductions in clinical signs associated with oral breathing, improvements in lip competence, and overall stability of the functional results achieved.

3. Statistical Analysis

The statistical framework of this study was designed to rigorously evaluate the hypothesis that a multidisciplinary approach provides superior outcomes compared to conventional orthodontic treatment alone. To ensure the validity and reproducibility of the clinical findings, several layers of analysis were employed.

Data Processing and Methodology

Initially, all collected data were subjected to descriptive statistical analysis, with results expressed as means and percentages to characterize the study population at both baseline (T0) and follow-up (T1). To verify the homogeneity of the sample, the two groups were matched for age, sex distribution, and baseline clinical characteristics, ensuring that any subsequent differences were attributable to the therapeutic intervention rather than initial variance. The primary and secondary outcomes — including the restoration of nasal breathing and the reduction of associated signs like bruxism, nocturnal movements, and lip incompetence — were quantitatively assessed. To determine the significance of the changes observed between T0 and T1 within each group and to compare the effectiveness of Group 1 and Group 2, paired t-tests were used. This statistical test was selected for its efficacy in comparing means from the same subjects over time or between closely matched groups.

Significance and Robustness

The threshold for statistical significance was predefined at p < 0.05. However, the data analysis revealed a much higher level of statistical robustness across all primary parameters. Specifically, the comparison between the RPE-only group and the RPE + MT group was significant (p < 0.001). This indicates an extremely low probability that the observed superior outcomes in the combined therapy group occurred by chance.

Qualitative Assessment and Reliability

In addition to quantitative metrics, qualitative data from the Glatzel mirror test (Figure 2) were analyzed to evaluate the symmetry and intensity of nasal airflow. To reduce inter-examiner variability and ensure the reliability of the statistical output, all clinical evaluations and data entries were performed by the same clinician.

Summary of Statistical Results at T1

The statistical divergence between the groups confirms that integrating myofunctional therapy significantly enhances the patient’s functional adaptation, yielding a more stable and effective resolution of oral breathing habits than purely structural expansion [15].

4. Results

All 40 patients completed the study protocol and were included in the final analysis. No significant differences were observed between the two groups at baseline (T0) in terms of clinical characteristics.

Primary Outcome: Nasal Breathing

The results at the six-month follow-up (T1) demonstrated a positive trend in both cohorts, as qualitatively confirmed by the Glatzel mirror test. However, the degree of functional recovery was significantly greater in the group treated with the combined protocol than in those receiving only mechanical expansion. Specifically, the clinical data revealed the following:

Group 1 (RPE only): The prevalence of oral breathing decreased from 100% at baseline (T0) to 40% at T1. While the expansion of the maxillary arch improved airway patency, a considerable portion of the group failed to transition spontaneously to nasal breathing [11,25,28].
Group 2 (RPE + Myofunctional Therapy): This group showed a substantially higher clinical success rate, with the prevalence of oral breathing dropping from 100% at T0 to just 10% at the six-month mark.

These findings suggest that while Rapid Palatal Expansion effectively addresses the structural deficiency, integrating myofunctional therapy is essential to correct persistent neuromuscular dysfunction [16]. This multidisciplinary approach ensured a significantly higher and more stable restoration of nasal breathing (p < 0.001).

**Figure 3.** Qualitative Assessment of Nasal Airflow at 6-Month Follow-up (T1).

Secondary Outcomes

Regarding the secondary outcomes, significant improvements were observed in both groups across all evaluated clinical signs, with more pronounced results in the group receiving combined therapy.

Bruxism: In Group 1, the prevalence decreased from 60% to 35%, whereas in Group 2, it decreased from 65% to 15%.
Nocturnal Movements: A similar trend was noted for nocturnal movements, which were reduced from 50% to 30% in the RPE-only group, compared to a sharper decline from 55% to 10% in the RPE + MT group.
Drooling During Sleep: Instances of drooling during sleep fell from 55% to 25% in Group 1, whereas Group 2 achieved a near-total resolution, with prevalence falling from 60% to just 5%.
Lip Incompetence: Finally, lip incompetence showed a marked improvement in both cohorts; however, Group 2 exhibited a superior outcome, reducing prevalence from 75% to 10%, while Group 1 decreased from 70% to 40%.

**Figure 4.** Prevalence of Secondary Clinical Signs at 6-Month Follow-up (T1).

Glatzel Mirror Assessment

The qualitative assessment of nasal airflow through the Glatzel mirror test at the six-month follow-up (T1) revealed a clear distinction in functional recovery between the two cohorts. Symmetrical nasal airflow was achieved by the vast majority of patients in Group 2 (90%), significantly exceeding the 60% success rate recorded in Group 1. Regarding persistent functional limitations, reduced airflow was noted in only 10% of the combined therapy group, whereas it persisted in 30% of the group treated with RPE alone. A particularly significant clinical finding was the complete elimination of severe obstructive patterns in the multidisciplinary group, with no cases of absent airflow recorded in Group 2 at T1, further confirming the efficacy of myofunctional re-education in stabilizing the patency achieved through mechanical expansion [17].

5. Discussion

The present study aimed to evaluate whether adding myofunctional therapy to rapid palatal expansion could improve functional outcomes in pediatric patients with oral breathing habits [9,14]. The findings clearly indicate that the combined approach provides superior results compared to RPE alone [9]. While both groups showed improvement in nasal airflow following expansion, the persistence of oral breathing in a substantial proportion of patients treated with RPE alone highlights a key limitation of purely structural interventions [1–2,18]. These findings are consistent with previous literature suggesting that anatomical correction does not necessarily translate into functional normalization [12].

The significantly greater reduction in oral breathing observed in the combined therapy group suggests that myofunctional therapy plays a critical role in reprogramming neuromuscular patterns [16,19]. Oral breathing is not merely a consequence of anatomical restriction but is often maintained by learned behaviors and altered muscle function [20]. Therefore, without targeted re-education, patients may continue to rely on dysfunctional respiratory patterns despite improved airway dimensions [2,21].

The improvement in secondary clinical signs, such as bruxism, nocturnal movements, and drooling, further supports the hypothesis that myofunctional therapy contributes to a broader functional reorganization. These signs are commonly associated with altered breathing patterns and poor neuromuscular coordination during sleep. Their reduction in the combined therapy group may reflect improved physiological stability and better-quality sleep [3,22].

An important aspect of this study is the timing of the myofunctional intervention. Initiating therapy one month before RPE likely enhanced patient awareness and facilitated early neuromuscular adaptation [16,23]. This preparatory phase may have reduced resistance to functional change and improved compliance during treatment. Furthermore, the continuation of therapy after expansion appears crucial for consolidating newly acquired functional patterns and preventing relapse [24].

The results also demonstrated improved lip competence and tongue posture in the combined therapy group. These factors are essential for maintaining nasal breathing and ensuring long-term stability of orthodontic outcomes [2,25]. In contrast, patients treated with RPE alone showed less consistent improvement in these parameters, suggesting incomplete functional adaptation. From a clinical perspective, these findings support integrating myofunctional therapy into orthodontic treatment protocols for patients with oral breathing. A multidisciplinary approach involving orthodontists and speech therapists may be considered the most effective strategy for addressing both structural and functional aspects of this condition [7,26,27].

Limitations

This study presents some limitations: a relatively small sample size, a short-term follow-up (6 months), and reliance on clinical and qualitative assessment methods. Future studies should include larger samples, longer follow-up periods, and objective instrumental evaluations such as rhinomanometry or polysomnography.

6. Conclusion

The results of the present study demonstrate that rapid palatal expansion (RPE), while effective in improving nasal airway dimensions, is not sufficient on its own to ensure the stable restoration of nasal breathing in pediatric patients with oral breathing habits [28]. The addition of myofunctional therapy, initiated before expansion and continued during and after treatment, significantly enhances functional outcomes. Patients receiving combined therapy showed greater improvements in nasal breathing, a more pronounced reduction in associated clinical signs, and improved neuromuscular coordination. Importantly, the combined approach resulted in greater stability of the outcomes achieved, suggesting that integrating structural and functional treatment modalities is essential for long-term success [29–30].

Clinical Implications

Multidisciplinary approach: The management of oral breathing should involve collaboration between orthodontists and speech therapists to address both anatomical and functional aspects.
Early intervention: Initiating myofunctional therapy before orthodontic treatment enhances patient awareness and facilitates neuromuscular adaptation.
Functional re-education is essential: Structural correction alone does not guarantee normalization of breathing patterns; targeted therapy is required to reprogram dysfunctional habits.
Improved treatment stability: The addition of myofunctional therapy reduces relapse risk and supports long-term maintenance of results.
Comprehensive patient management: Evaluation of clinical signs such as bruxism, nocturnal movements, drooling, and lip incompetence should be routinely included in the diagnostic process.

**Figure 6.** Comparison of Clinical Outcomes at 6-Month Follow-up (T1).

7. Declarations

Funding

The authors declare that no external funding was received for this study.

Informed Consent Statement

Written informed consent was obtained from all study participants and from parents or legal guardians for minor participants.

Data Availability Statement

The data presented in this study are available from the corresponding author upon reasonable request, subject to ethical and privacy restrictions.

Conflicts of Interest

The authors declare no conflict of interest.

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