Stomatognathic system and the impact of the tongue on postural development during childhood: a systematic review

Introduction

Numerous studies have explored the complex relationship between dental occlusion, tongue function, and body posture (2, 3, 7, 10, 20, 33). In pediatric populations, these factors are even more critical as they interact during key neuromuscular and skeletal development phases. The tongue is a central functional element within the stomatognathic system (26), contributing to swallowing, phonation, and oro-cervicocephalic balance.

The facial mass plays a crucial role in craniofacial growth and dental occlusion. Although not classified as a primary postural receptor (6), the stomatognathic system may exert biomechanical influence on postural regulation but can act as a postural interference, potentially affecting overall body posture.

The influence of the tongue on global postural imbalance remains a subject of debate and lacks universal recognition. Nevertheless, its significance is more widely acknowledged in the cervical region, owing to its critical functions such as breathing and swallowing. Additionally, the connection between the tongue and the anterior chain of the myofascial meridians indicates a possible impact on posture, particularly in instances of a short lingual frenulum (6) (27). As early as the 1990s, Ait-Abbas et al. emphasized the relationship between occlusion and posture during childhood development (1).

The theoretical framework proposing that alterations in tongue position or function may impact overall body posture is grounded in the understanding of myofascial chains, anatomical connections, and clinical observations of compensatory adaptations. Imaging studies, such as that conducted by Decocq et al. (10), have demonstrated that changes in cephalometric parameters following orthodontic intervention may be associated with modifications in static posture (10). Various researchers, including Lippold et al. (17, 18) and Tecco et al. (36), have examined the relationship between occlusion and spinal alignment, identifying correlations between malocclusions and postural variations in the spine, pelvis, or head. Although this systematic review is centered on the pediatric population (0–18 years), selected studies involving adults provide valuable methodological insights. Ohlendorf, D. M., et al., have yet to establish the feasibility of objective postural assessment utilizing 3D scanning in conjunction with mandibular analysis (29). In addition, Decocq et al. emphasized the influence of occlusion on postural alignment, thereby supporting the notion of the stomatognathic system as a postural receptor (10). While these findings are not directly applicable to children, they offer theoretical and methodological support for future investigations into these relationships within pediatric populations.

Surgical interventions such as frenotomy and orthognathic correction for Class III malocclusion have a structural impact on craniofacial and cervical posture. Conversely, postural therapies operate through neuromuscular adaptation. Although outcomes of surgical procedures in adults are documented, the efficacy of pediatric postural correction remains insufficiently explored, thereby emphasizing a gap in early functional intervention.

In pediatric dentistry and orthodontics, posture assessment often precedes the analysis of occlusion and dental development. Understanding the global postural framework helps contextualize how the stomatognathic system might interact with or influence overall body balance. Postural assessment is an integral part of pediatric dentistry (23).

Although these relationships are of significant interest to orthodontists, physiotherapists, and speech therapists, the literature remains heterogeneous, with varying methodologies and study designs that complicate clinical generalization.

This review seeks to collect and synthesize the existing evidence concerning the association between tongue function, occlusion, and posture within pediatric populations. It emphasizes correlations with spinal alignment, cervical posture, and head orientation. The purpose is to offer a comprehensive overview to support multidisciplinary clinical practice and to guide future research efforts.

Materials and methods

Inclusion Criteria

• Studies involving children and adolescents (0–18 years).
• Research examining the relationship between tongue position and function, the stomatognathic system, and postural parameters such as head orientation, cervical spine alignment, and overall posture.
• Study designs include randomized controlled trials (RCT), observational studies such as cross-sectional, cohort, and case-control studies, as well as clinical studies and relevant systematic reviews.
• Studies encompassing postural assessment techniques, such as clinical, radiographic, baropodometric, or photographic methods.
• Studies with explicitly documented outcomes concerning body posture, cervical alignment, or musculoskeletal orientation.

Exclusion Criteria

• Research concerning adult populations.
• Case reports, editorials, commentaries, and conference abstracts without full texts.
• Studies are not reporting postural outcomes or investigating the tongue/stomatognathic system.
• Surgery-based studies
• Articles are not accessible in full-text format.

Study Selection Process

Two independent reviewers conducted screening of titles and abstracts to determine eligibility. Full texts of potentially pertinent articles were evaluated according to specified inclusion and exclusion criteria. Any disagreements were addressed through discussion or, if necessary, by consulting a third reviewer. Additionally, reference lists from included articles were manually examined to identify further relevant studies. Several studies deemed potentially relevant were excluded at the full-text review stage because the study populations did not align with the predefined age criteria. These exclusions primarily resulted from the inclusion of participants aged 18 years or older, which fell outside the scope of this pediatric-focused review.

A PRISMA flow diagram was constructed to summarize the selection process.

Data Extraction

For each included study, the following information was extracted:

• First author, year of publication
• Study design
• Sample Size and Age Range
• Evaluation methods of tongue and stomatognathic parameters.
• Methods of Postural Assessment
• Main findings and correlations
• Certain studies, including those involving adult populations or surgical interventions lacking preoperative postural assessment, did not meet the predetermined inclusion criteria and are cited within the text for methodological comparison. Their inclusion highlights existing gaps within pediatric research and underscores the importance of postural and stomatognathic interactions across different age groups. These studies were not incorporated into the systematic review and did not impact the formal synthesis (Fig. 1).

Quality Assessment: The AXIS tool evaluates the risk of Bias (RoB) in observational studies. The STROBE statement is employed for quality assessment in observational research. The Jadad scale is utilized for randomized controlled trials (RCTs). The ROB 2 tool is applied for RCT assessments. The ROBIS tool is used to evaluate systematic reviews. The AMSTAR 2 instrument assesses the quality of included systematic reviews.

Data Synthesis: Statistical synthesis and summary tables presented.

Study Selection: The initial search yielded 1,091 potentially relevant records. Following the removal of 54 duplicates, 1,037 unique records remained for screening. In the first screening phase, based on titles and abstracts, 701 records were excluded as they did not meet the inclusion criteria. The remaining 336 articles underwent full-text assessment for eligibility. After detailed evaluation, 309 articles were excluded for reasons such as inadequate methodological quality, irrelevant outcomes, or failure to meet predefined criteria. Consequently, 30 studies were included in the final systematic review

Results

Due to the marked heterogeneity of the included studies in terms of design, population, measured postural and occlusal parameters, and assessment methods (photogrammetry, radiography, podometric analysis, cephalometric analysis), it was not possible to perform a conventional meta-analysis based on effect size measures (odds ratio, standardized mean difference, hazard ratio) and their confidence intervals.

Numerous studies have reported solely p-values or correlations without providing comprehensive descriptive statistics (such as mean, standard deviation, and sample size per group), thereby hindering the standardization of effect sizes.

Consequently, the quantitative synthesis relied on:

• A structured descriptive synthesis is organized by type of malocclusion, postural alteration, and cephalometric parameter, reporting for each study the main results, the direction of the association, and the level of statistical significance.
• A systematic evaluation of methodological quality and risk of bias is conducted utilizing frameworks such as STROBE, Jadad, AMSTAR 2, along with specialized instruments including AXIS, ROB 2, and ROBIS.

Statistical Analysis — Quantitative Synthesis of p-values

A total of 58 p-values were manually extracted from the Results sections of 30 included studies, encompassing cross-sectional, longitudinal, and randomized designs. Due to heterogeneity in study designs, the p-values were synthesized without weighting by sample size or study quality and should be regarded as exploratory rather than confirmatory. These values were obtained from various statistical tests reported by the authors, including Student’s t-test, χ² test, ANOVA/MANOVA, correlation analyses, and logistic regression models.

All p-values were converted into decimal format. Implausible values (p ≤ 0 or p > 1) and descriptive statements lacking numeric p-values (e.g., “not significant” without a reported p) were excluded. When multiple p-values pertained to the same test but different outcomes, each was maintained separately to accurately represent the distribution of evidence.

Fisher’s Method

The combined statistic was calculated as: X² = −2 ∑ ln(pᵢ) where k represents the number of included studies. Applying this method to the collected data yielded a combined p-value < 0.0001, indicating highly significant overall evidence.

Stouffer’s Method (Unweighted)

Each p-value was transformed into a standardized Z-score and combined as follows: Z = (∑ Zᵢ) / k. This methodology, which exhibits greater sensitivity to the overall distribution of p-values rather than solely focusing on extreme values, yielded a combined p-value approximately equal to 1.0, thereby indicating a high proportion of studies with non-significant outcomes.

The distribution pattern of the extracted p-values indicated a small cluster of studies with exceptionally low values (p < 0.01), alongside a majority exceeding the conventional significance threshold (p > 0.05).

Interpretation

The pronounced distinction between the findings of Fisher and Stouffer indicates that, although certain individual studies demonstrate strong statistical significance, the majority of the available evidence does not substantiate a consistent or statistically significant association. Fisher’s method, which is sensitive to small p-values, emphasizes the impact of a few highly significant results, whereas Stouffer’s method, offering a more balanced perspective, mirrors the general absence of statistical significance.

Given the absence of uniform effect size data and the reliance on p-values alone, these findings should be interpreted with caution. The primary strength of this review lies in the qualitative synthesis and methodological quality assessment, which provide a critical framework for future high-quality studies that should report effect sizes and confidence intervals to enable robust quantitative meta-analysis.

Descriptive Results of Included Studies

Limitations

Despite a comprehensive search including published and grey literature, this review faces several limitations: Methodological heterogeneity across included studies regarding design, sample size, and postural assessment techniques limits comparability and generalizability. The majority of studies are observational and cross-sectional, restricting causal inference and longitudinal insights. However, some RCTs and longitudinal studies strengthen the overall evidence quality. Lack of standardized, objective postural metrics and limited control for confounding factors (e.g., visual, vestibular, respiratory influences) reduce internal validity. Potential publication bias and geographic concentration of studies may affect representativeness. Several potentially relevant studies were excluded based on predefined criteria, including participant age outside the pediatric range. Details of these excluded studies have been retained in the project archive for transparency and future reference. Absence of standardized effect size data prevented formal meta-analysis.

Grade assessment

The overall quality of evidence is moderate. While methodological heterogeneity limits generalizability, clinical consistency and biomechanical plausibility support the conclusions. Future research should prioritize standardized methods and longitudinal designs to enhance evidence robustness.

Assessment of Methodological Quality and Risk of Bias

Methodological assessment of quality (STROBE, Jadad Scale, AMSTAR 2)

STROBE

The majority of the observational studies included in this review demonstrate a moderate methodological quality based on the STROBE criteria. Objectives are generally well articulated, and descriptions of populations are adequate, although in certain instances, the sample sizes are limited or not entirely representative. Postural measurement techniques exhibit considerable variability: some studies utilize objective tools such as rasterstereography or radiography, while others depend on more subjective methodologies, including clinical photography or direct observation. This variability contributes to methodological heterogeneity, which restricts comparability across studies. Statistical analyses are predominantly descriptive, with only a few studies employing multivariate models to account for confounding variables. The absence of adjustments for variables such as visual input (5,13,33), vestibular function, or respiration constitutes a common methodological limitation. Certain studies, such as those by Perinetti et al. (31) and Kim et al. (14), stand out for their moderate-to-high quality owing to more comprehensive reporting and more robust statistical analyses. Conversely, studies such as Cerruto et al. (8) and Bevilaqua-Grossi et al. (4) exhibit significant limitations, including poorly defined objectives, small sample sizes, and measurement methods lacking validation. Overall, the quality of reporting is sufficient to support the narrative synthesis of this review but underscores the necessity for future research to adopt more standardized and methodologically rigorous approaches.

Jadad Scale

Lippold et al. (17) achieved a Jadad score of 3 out of 5. This score indicates a study of moderate methodological quality. While the randomization process and reporting of attrition are conducted with robustness, the lack of blinding presents a potential risk of bias. Nevertheless, the utilization of objective measurement tools (e.g., rasterstereography) may alleviate some concerns associated with detection bias.

Cerruto et al. (8) attained a Jadad score of 2/5. This score signifies a study of low to moderate methodological quality. Although the trial is randomized and participant selection is well-documented, the absence of blinding and insufficient details concerning the randomization process present potential risks of bias. Nevertheless, the application of objective, computerized photographic measurements may alleviate some concerns associated with detection bias.

Tecco et al. (36) achieved a Jadad score of 2/5, indicating a study of low to moderate methodological quality. Although the trial is described as randomized and reports complete follow-up without attrition, the absence of a detailed randomization procedure and the lack of blinding may introduce potential biases. Nonetheless, the employment of objective cephalometric measurements could mitigate concerns related to detection bias.

AMSTAR 2

Di Palma et al. (11) received a moderate overall confidence rating. The review is well conducted in several key methodological domains but exhibits some limitations, including the absence of a registered protocol, lack of a detailed list of excluded studies, and the inability to perform a meta-analysis due to heterogeneity among included studies. The synthesis remains descriptive, with acknowledged limitations and an acceptable level of transparency. The systematic review was included in accordance with the predefined inclusion criteria; however, to maintain consistency with the pediatric and adolescent focus, only data pertaining to subjects aged 0 to 18 years were considered. This approach ensured homogeneity of the studied population and allowed for analysis of postural adaptations specific to growth phases.

Neiva et al. (28) state that, according to AMSTAR 2 guidelines, the presence of multiple weaknesses in critical domains—specifically the lack of protocol registration, the absence of documentation regarding excluded studies, and the omission of publication bias assessment results—results in a low overall confidence in the findings of the review. While the narrative synthesis is coherent and methodologically sound within its scope, the absence of key safeguards against bias diminishes the reliability and generalizability of the conclusions.

Discussion

Despite the lack of consistent statistical significance across the whole body of evidence, the presence of isolated studies with highly significant results suggests that specific postural and occlusal relationships may hold clinical relevance. In particular, the associations observed in studies with extremely low p-values, though not representative of the entire dataset, may reflect genuine biomechanical or functional interactions that are observable in practice.

From a clinical perspective, these findings highlight the significance of incorporating postural assessment into pediatric dental and orthodontic practice (3, 9, 36). Although the aggregated data do not substantiate a universal or strong correlation, the presence of specific effects in certain populations (e.g., Class II malocclusion with forward head posture (6), pelvic asymmetries associated with dental crowding) may warrant individualized evaluation and interdisciplinary collaboration between orthodontists and physiotherapists specializing in posturology.

Ultimately, the existing evidence underscores the necessity for future research incorporating standardized methodologies, objective postural measurements, and explicitly defined occlusal classifications. Such investigations would enable clinicians to transcend anecdotal observations and adopt evidence-based protocols that integrate postural evaluation into dental and orthodontic practices (23).

Summary of key findings: tongue function, occlusion, and posture

this review underscores the intricate and reciprocal relationship among tongue function, dental occlusion, and postural alignment, especially in developing individuals. Given its central role in swallowing, respiration, and phonation, the tongue can influence myofascial chains and impact overall posture (27). Evidence indicates that dysfunctions such as a short lingual frenulum and mouth breathing are correlated with cervical and scapular modifications, whereas malocclusions like unilateral crossbite may affect limb symmetry and balance. It is recommended to conduct early screening for Class II malocclusions during preschool years (18), thereby emphasizing the significance of prompt interdisciplinary assessment.

The cervical spine serves as a vital anatomical connection between craniofacial structures and overall posture. Cervical posture is predictive of craniofacial development (32), and vertical growth patterns also influence cranio-cervical posture (20), thereby adding complexity to diagnostic assessments. Research has demonstrated that skeletal anomalies and malocclusions can affect cervical vertebral morphology and head orientation. Orthodontic interventions, such as rapid palatal expansion, may have a positive impact on cervical posture (36), although the methodological quality of evidence varies. Additionally, plantar posture is altered in children with malocclusions (24), indicating a broader influence on overall posture beyond the craniofacial region.

Head posture is intricately linked to occlusal patterns. Variations in head positioning are frequently observed in cases of open bite, crossbite, and dental crowding. Such modifications may represent compensatory mechanisms or could potentially worsen dysfunction. Interventions focused on occlusal correction have shown promise in affecting head and scapular posture (3)(8), suggesting possible therapeutic advantages.

Furthermore, vertebral posture, including thoracic kyphosis and pelvic torsion, has been linked to nasopharyngeal obstruction and craniofacial asymmetries (21)(7). The sagittal alignment of the spine may reflect or aggravate occlusal discrepancies, indicating a broader systemic involvement. Several studies suggest that reducing overjet or rectifying skeletal Class II malocclusion can impact pelvic rotation and spinal equilibrium (15)(37).

Postural rehabilitation approaches, such as global postural re-education, have shown promise in improving both musculoskeletal alignment and stomatognathic function (5). These findings support the integration of orthodontic and postural therapies, especially in pediatric populations where growth modulation is still possible.

In conclusion, the literature supports an integrated view of the stomatognathic system and posture, emphasizing the need for multidisciplinary collaboration in diagnosis and treatment. However, variability in study design and assessment methods calls for more rigorous research to clarify causal relationships and optimize clinical strategies.

Conclusions

Postural regulation during childhood is a dynamic process that evolves concurrently with skeletal maturation, neuromuscular coordination, and sensorimotor integration. The stomatognathic system, particularly the tongue and dental occlusion, interacts with these developmental processes subtly yet potentially significantly. During growth, compensatory mechanisms may arise to adapt to functional imbalances such as altered tongue posture or malocclusion, which can influence cervical alignment, scapular symmetry, and pelvic orientation.

Given the inherent plasticity of the musculoskeletal system in pediatric populations, early identification of dysfunctions within the stomatognathic system offers a valuable opportunity for preventive intervention. Addressing these dysfunctions during critical growth periods may mitigate the risk of long-term postural deviations and associated musculoskeletal complications.

The relationship between craniofacial structures and posture extends beyond direct mechanical effects. Although the stomatognathic system is not classified as a primary postural receptor, it may serve as a source of biomechanical and neuromuscular interference, particularly within the cervical region. The tongue, while not universally recognized as a determinant of global postural imbalance (6, 26), plays a pivotal role in cervical alignment and foundational functions such as respiration and swallowing. Its integration within myofascial chains further supports its potential significance in postural regulation, especially in cases involving a short lingual frenulum (26).

These findings emphasize the significance of evaluating both functional and anatomical aspects of the stomatognathic system in the assessment of postural patterns and the development of therapeutic interventions (30). Notably, visual input, particularly ocular function, exerts a substantial influence on postural control, yet it remains largely neglected in studies investigating the interaction between posture and the stomatognathic system (5,13, 35). This lacuna in the literature underscores the necessity for future research to incorporate visual parameters, thereby enhancing the understanding of the complex interplay among sensory and anatomical systems involved in postural regulation.

In summary, the stomatognathic system, particularly the tongue, should be considered not solely in terms of oral function but also as a potential contributor to postural dynamics (22). A multidisciplinary approach involving dentists and physiotherapists specialized in posturology may prove beneficial not only for treatment but also as a preventive strategy during critical phases of growth and development. Interdisciplinary collaboration can facilitate early identification of compensatory mechanisms and support integrated care pathways aimed at optimizing both functional and postural outcomes.

Clinical recommendations

Based on the current body of evidence and clinical insights, it is advisable to integrate postural screening into routine orthodontic evaluations, with particular attention to cervical and craniofacial posture in cases of Class II malocclusion, Class III malocclusion, cross bite, open bite, or tongue dysfunction. Establishing collaborative referral pathways among orthodontists, physiotherapists, and speech therapists is essential to ensure comprehensive assessment and management of stomatognathic and postural dysfunctions. Monitoring postural changes closely during rapid growth phases, such as prepubertal periods, is critical, as compensatory mechanisms may become more pronounced. Thus, these clinical recommendations should be applied cautiously and adapted to individual patient contexts. Additionally, educating families on functional habits including breathing patterns, tongue posture, and oral behaviours that influence occlusion and posture can enhance preventive efforts. Early identification and management of tongue-related dysfunctions, such as short lingual frenulum or low resting posture, may reduce the risk of persistent postural imbalances.

Future directions

To advance understanding and improve clinical application, future research should prioritize the standardization of assessment protocols by developing and adopting unified, validated, and reproducible tools for evaluating both stomatognathic and postural parameters. Incorporating multisensory analyses that include visual, vestibular, and proprioceptive inputs will better capture the complexity of postural regulation. Longitudinal studies tracking changes over time particularly before and after orthodontic or myofunctional interventions are warranted to clarify causality and therapeutic impact. Furthermore, reporting effect sizes and confidence intervals alongside p-values is essential to quantify the magnitude and clinical relevance of observed associations. Finally, investigating preventive strategies aimed at early identification and correction of stomatognathic dysfunctions may offer critical insights into reducing the incidence of long-term postural deviations.