The Airway-Centric Craniofacial Adaptation Theory (ACCAT)

Introduction to the Theory

In the pursuit of understanding and potentially improving craniofacial development, the practices of mewing have caused significant attention within both orthodontic circles and the broader community interested in non-surgical methods of facial structure improvement. Mewing involves maintaining a specific tongue posture, pressing the entire tongue against the roof of the mouth. This practice, theorized by Dr. John Mew, is proposed to influence craniofacial anatomy positively over time.

To explore the underlying mechanisms of how mewing may influence craniofacial structures, this theory integrates two fundamental principles of bone adaptation: Wolff's Law and Melvin Moss's Functional Matrix Theory. Wolff's Law posits that bones remodel in response to the mechanical stresses placed upon them, suggesting that sustained tongue pressure could lead to bone growth and remodeling in the maxilla and related structures. Meanwhile, the Functional Matrix Theory proposes that craniofacial growth is primarily driven by functional needs, with cranial bones developing as secondary adaptations to the spaces required by cranial functions, such as the airway.

The goal of the Theory

The primary goal of this theoretical framework is to safely explore how mewing can create favorable craniofacial changes, potentially including subtle but beneficial modifications to the airway. These changes are hypothesized to occur through holistic remodeling, driven by the constant, natural pressure exerted by proper tongue posture and the True Mewing practice:

  1. Objective: To balance the principles of Wolff's Law and the Functional Matrix Theory to assess and promote the potential of mewing for improving craniofacial alignment and function. The focus is on how sustained pressure from the tongue might influence the craniofacial bone structure, particularly around the airway, to achieve a more anatomically favorable and functionally effective position.
  2. Safety and Monitoring: Emphasizing the importance of safety, any modifications to the craniofacial structure, especially those affecting the airway, should be approached cautiously. The aim is to ensure that these changes do not compromise respiratory functions and are implemented gradually and under professional observation when absolutely necessary.
  3. Outcomes: The expected outcomes include improved craniofacial alignment and symmetry, enhanced jawline definition, optimized occlusal relationships, and potential benefits to respiratory functions. These changes are anticipated to contribute to both the aesthetic and functional enhancement of the craniofacial region.

    The Airway-Centric Craniofacial Adaptation Theory 

    The "Airway-Centric Craniofacial Adaptation Theory" (ACCAT) proposes that deliberate and consistent application of tongue pressure against the palate in conjunction with neck posture exerts direct mechanical forces on the maxilla and influences the broader craniofacial structure by affecting the airway space. This process operates through several biomechanical and physiological mechanisms:

    The Airway as a Functional Matrix

    According to Moss's Functional Matrix Theory, the growth and development of bones are significantly influenced by the spaces that these bones encase. In the context of mewing, tongue and neck posture can impact the airway space. This alteration potentially initiates adaptive responses in the craniofacial skeleton, aiming to optimize airway functionality while promoting anatomical remodeling.

    ACCAT hypothesizes that mewing by carefully restricting airflow through specific tongue and neck positions may lead to an adaptive response in the surrounding craniofacial complex. This adaptive response is aimed at maintaining optimal airway function while also encouraging favorable anatomical changes. These changes may include the forward and upward development of facial bones, enhancing both facial aesthetics and functional outcomes.

    How to practice ACCAT

    Suction Hold Technique 

    The suction hold is a fundamental aspect of mewing, where the practitioner applies the entire tongue against the roof of the mouth, creating a suction effect. This technique not only helps stabilize the tongue in the correct position but also enhances the pressure exerted upward against the maxilla. The key is to achieve a balance where the tongue firmly but comfortably covers the palate, promoting effective and continuous mechanical stimulation necessary for bone remodeling, as suggested by Wolff’s Law.

    Chin Tuck 

    The chin tuck complements the suction hold by aligning the cervical spine (neck) and enhancing the postural dynamics that influence the craniofacial structure. When performed properly, a slight chin tuck positions the head directly over the spine, encouraging the natural curvature of the cervical vertebrae. This alignment facilitates the optimal positioning of the tongue against the palate and, importantly, slightly restricts the airway when proper tongue posture is used. The restriction is not meant to impede breathing but to subtly increase airway resistance, which can prompt adaptive responses in the surrounding craniofacial tissues.

    Mechanism of Airway Restriction

    By carefully controlling the tongue’s posture and the neck’s alignment, the airway will become restricted (ensure a safe practice). This controlled narrowing is intended to act as the basis for adaptive craniofacial remodeling. The theory proposes that this slight restriction enhances the functional demand on the airway, leading to a physiological response where the surrounding cranial structures may adapt to maintain adequate airway function. These adaptations could include the forward growth of the jaw or expansion of the nasal passages, which not only help maintain good airflow but also improve the overall facial aesthetics.

    Integrating Suction Hold and Chin Tuck

    The integration of the suction hold and chin tuck is important for the effective application of mewing techniques. Together, they ensure that the tongue exerts uniform pressure across the palate, which is essential for achieving the desired bone remodeling effects. Moreover, the combined effect of these techniques supports a more structured and aligned posture, crucial for the holistic development of the craniofacial complex as outlined in the Airway-Centric Craniofacial Adaptation Theory.

    Nuances and Considerations in Mewing Practice

    The Nuance of Time

    One of the most significant nuances in mewing practice is the time required to observe noticeable changes. Craniofacial remodeling is a gradual process influenced by several factors including age, and the baseline craniofacial structure:

    • Younger Individuals: Changes may be more rapid and pronounced due to the greater plasticity of bones and ongoing growth processes.
    • Adults: Modifications in adults can take longer and may be less dramatic. Consistent practice over several years might be necessary to see tangible results.

    The Nuance of Technique

    The effectiveness of mewing is heavily dependent on mastering the technique, particularly the position of the tongue and the posture of the neck:

    • Tongue Positioning: The entire tongue should be pressed against the palate, not just the tip or the middle. Incorrect positioning can lead to ineffective pressure distribution, potentially stressing the wrong areas. In addition, this posture should be ideal subconsciously for most of the individual's life.
    • Neck Posture: The slight chin tuck must be enough to align the cervical spine without causing discomfort or excessive strain. Over-extension or incorrect forward posture can negate the benefits of mewing or lead to other issues like neck pain. In addition, this posture should be ideal subconsciously for most of the individual's life.


    The "Airway-Centric Craniofacial Adaptation Theory" provides a comprehensive framework that integrates fundamental principles from Wolff’s Law and Moss's Functional Matrix Theory with practical techniques such as mewing. This theory highlights the dynamic interplay between function and epigenetic factors—specifically, functional demands that significantly shape craniofacial development. It challenges traditional views that attribute craniofacial growth primarily to genetic determinants, emphasizing instead the pivotal role of functional adaptations driven by everyday behaviors such as tongue positioning and posture.

    If you're interested in discussing mewing techniques, craniofacial development theories, or any related topics further, you're welcome to join the MewTropics Discord community. It's a great place to connect with others who share your interests, and you can find support, share experiences, and learn more in a dedicated environment. Here’s the link to join:

    MewTropics Discord Server


    Wolff, J. (1892). Das Gesetz der Transformation der Knochen. Berlin: Hirschwald. 

    Moss, M. L. (1968). "A theoretical analysis of the functional matrix." Acta Biotheoretica, 18(1), 195-202. 

    Mew, J. R. (1999). "The postural basis of malocclusion: A philosophical overview." American Journal of Orthodontics and Dentofacial Orthopedics, 116(6), 590-596. 

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