Abstract
Facial bone morphology has traditionally been attributed to genetic and developmental factors. There are numerous scientific publications that highlight the role of the masticatory muscles in determining the development and evolution of the jaw bones, but very few publications mention the role of the non-masticatory muscles in shaping the facial bones during development and after maturity.
However, increasing evidence demonstrates that non‑masticatory muscular activities—such as facial mimicry, expressions, habits, lingual posture, perioral pressure, and nasal respiratory dynamics—play a crucial mechanobiologic role in shaping craniofacial structures throughout life.
This paper integrates recent research (2020–2025) with the Morphodynamic Cosmetic Surgery (MDCS) framework (Rizzo, 2020), emphasizing the reciprocal influence between functional muscle activity and bone remodeling.
A synthesis of studies using imaging, modeling, and clinical observation supports the principle that sustained low‑intensity mechanical stimuli from facial muscles induce adaptive bone responses consistent with the theory of mechanobiologic hormesis. This perspective underpins MDCS as a regenerative, function‑driven surgical philosophy where modulation of muscle vectors can guide soft and hard tissue regeneration.
1. Introduction:
The Morphodynamic Concept: the morphodynamic principle asserts that function determines form. The foundations of this biological philosophy date back to the 1892, when Julius Woolf formulated the Wolff’s Law:” Tension and compression stimulates bone deposition and increased density at points of stress, while a decrease in stress will cause the bone to weaken over time.
“In 1997 Melvin Moss developed the revolutionary Functional Matrix Theory:” The growth, development and maintenance of all skeletal tissues and organs are secondary, compensatory and obligatory responses to the functional demands of surrounding non-skeketal tissues, organs or functioning spaces”.
While classical craniofacial models emphasized genetic determinants, functional adaptation and mechanobiology now reveal a continuous dialogue between muscular forces and bone shape (Freidline et al., 2025).
The Morphodynamic Cosmetic Surgery (MDCS) paradigm (Rizzo, 2020) delve deeper into the topic of this principle and applies it to techniques of aesthetic and regenerative contexts, proposing that facial expressions, postural habits, and breathing patterns act as long‑term mechanical modulators of facial skeletal morphology and have an important role in aesthetic treatments.
2. Mechanobiologic Framework
Mechanobiology provides the foundation for understanding how mechanical forces translate into cellular and tissue responses. Osteocytes, fibroblasts, and myocytes perceive mechanical stimuli through integrins and cytoskeletal mechanosensors, activating signaling pathways such as YAP/TAZ and Wnt/β‑catenin (Wang et al., 2022).
Within the facial complex, periosteal bone remodeling continues in response to soft‑tissue tension, particularly along zones of muscle insertion and habitual expression (Freidline et al., 2025; Walczak et al., 2023; Rizzo 2020). This adaptive process aligns with Frost’s mechanostat theory, supporting a dynamic equilibrium between bone deposition and resorption influenced by the magnitude and frequency of functional strain.
3. Evidence from Recent Literature (2020–2025)
Recent studies demonstrate that facial musculature beyond the masticatory system significantly influences skeletal form. MRI and modeling approaches have clarified the spatial organization of the mimic muscles, linking their contraction vectors to underlying bone morphology (Schutte et al., 2024; Landfald et al., 2025). Lingual and perioral activities, including tongue pressure and lip sealing force, show quantifiable correlations with mid‑facial structure and alveolar bone shape (Nakamaru et al., 2025; Van Geneugden et al., 2023). Moreover, functional nasal airflow and respiration patterns affect nasomaxillary growth and remodeling (Hsu et al., 2024; Lee et al., 2024).
These findings indicate that everyday muscle dynamics maintain a subtle but persistent mechanical dialogue with craniofacial bone, validating the morphodynamic approach.
4. Implications for Morphodynamic Cosmetic Surgery (MDCS)
In the MDCS framework, the surgeon acts as a functional modulator rather than a mere sculptor.
By analyzing facial motion patterns through Morphodynamic Craniofacial Analysis (MD‑CFA), one can identify regions of hyper‑ or hypo‑activity and their mechanical consequences on skeletal and soft tissue morphology (Rizzo, 2024).
Interventions such as myomodulation with botulinum toxin, regenerative fillers, threads, or targeted stimulation protocols can rebalance mechanical vectors, restoring physiologic strain and guiding regenerative responses (Harris, 2019; Levrini et al., 2024).
The principle of mechanobiologic hormesis suggests that mild, repeated stimulation promotes anabolic tissue responses, whereas excessive mechanical load leads to degeneration. This duality reinforces the MDCS concept of controlled, functionally oriented rejuvenation.
5. Conclusions
Emerging evidence confirms that facial bone morphology is only partially genetically predetermined. Masticatory and non‑masticatory muscules and usual habits and functions —mimetic, lingual, and nasal—contribute substantially to the continuous modeling of the craniofacial skeleton.
Through mechanobiologic transduction, habitual soft‑tissue activity maintains or alters bone architecture, providing a biological rationale for Morphodynamic Cosmetic Surgery.
By integrating functional analysis with regenerative approaches, MDCS proposes a new paradigm where the aesthetic outcome is the visible expression of restored functional harmony.
References
Wolff J. Das Gesetz der Transformation der Knochen. Berlin: Hirschwald; 1892.
Moss ML. The FUNCTIONAL MATRIX Hypothesis. The role of Mechanotrasduction. Am I Orthod Dentofacial Orthop. July, 1997.
Freidline, S. E., Hubbart, M., & Schuh, A. (2025). Shaping the human face: periosteal bone modeling across ontogeny. Anatomical Record.
Hsu, L. F., et al. (2024). Craniofacial and olfactory changes after long-term unilateral nasal obstruction. Scientific Reports.
Landfald, I. C., et al. (2025). An interdisciplinary review of the zygomaticus muscles. *Journal of Clinical Medicine, 14*(12), 4110.
Lee, J. H., et al. (2024). Three-dimensional nasal cavity modeling and facial indices. Journal of Personalized Medicine, 14(4), 415.
Levrini, L., et al. (2024). Myofunctional therapy for facial rejuvenation and orofacial function: a systematic review. Audiology Research, 9*(2), 99.
Nakamaru, M., et al. (2025). Soft-tissue facial profile is associated with tongue pressure in adults. Cureus.
Rizzo A. Morphodynamic Cosmetic Surgery: holistic beauty, the new paradigms of Aesthetic Surgery. Amazon. Self publishing, 2020.
Rizzo, A. (2024). Morphodynamic Craniofacial Analysis. Chirurgia Cosmetica Morfodinamica. Available on line: https://www.chirurgiacosmeticamorfodinamica.it/2025/09/10/morphodynamic-craniofacial-analysis/
Schutte, H., et al. (2024). New method for analysing spatial relationships of facial musculature using MRI. Journal of Craniomaxillofacial Surgery.
Van Geneugden, L., et al. (2023). Relation between oral muscle pressure and dentoalveolar characteristics. Journal of Clinical Medicine, 12, 4598.
Walczak, M., et al. (2023). Muscle activity and age-related bone remodeling: a mechanostat perspective. Bone Reports.
Wang, X., et al. (2022). Mechanosensing pathways in bone homeostasis: integrins, YAP/TAZ, and Wnt signaling. Bone Research.
Harris, D. (2019). Myomodulation and facial dynamics: evolving paradigms. Aesthetic Plastic Surgery, 4
