Botulinum Toxin and Hyaluronic Acid Fillers in Contemporary Dental Practice: Mechanisms, Clinical Applications, Safety, and Future Directions

Botulinum Toxin and Hyaluronic Acid Fillers in Contemporary Dental Practice: Mechanisms, Clinical Applications, Safety, and Future Directions

Prof. Mohamad Hani Nouri Dalati *, Dr. Lara Koussayer ¹

1. Consultant Cosmetic Gynaecologist, Mediclinic Hospital, Abu Dhabi, UAE.

*Correspondence to: Prof. Mohamad Hani Nouri Dalati. Consultant Orthodontist, Implantologist, and Medical Director, Tajmeel Specialised Medical Centre, Al Dar HQ Building, Al Raha Beach, Abu Dhabi, UAE.

             
Copyright.

© 2026 Prof. Mohamad Hani Nouri Dalati, This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: 29 June 2026

Published: 01 July 2026

DOI: https://doi.org/10.5281/zenodo.21094181

Abstract

Background: Botulinum toxin (BoNT) and hyaluronic acid (HA) fillers have become increasingly integrated into contemporary dental practice, reflecting a shift toward minimally invasive, functional, and aesthetic orofacial care. Their applications now extend beyond cosmetic enhancement to include management of temporomandibular disorders (TMD), bruxism, orofacial pain, masseter hypertrophy, and perioral soft tissue dysfunction.

Aim: To synthesise current evidence on the mechanisms, clinical applications, safety considerations, and future directions of BoNT and HA fillers within dentistry, while maintaining alignment with high quality clinical research and interdisciplinary practice.

Methods: A narrative review of literature published between 1995 and 2025 was conducted using MEDLINE, PubMed, EMBASE, Scopus, and the Cochrane Library. Priority was given to systematic reviews, randomised controlled trials, consensus statements, and high impact dental and medical publications.

Results: BoNT demonstrates consistent benefit in conditions involving muscular hyperactivity, including bruxism, masseter hypertrophy, myofascial pain, and selected TMD phenotypes. HA fillers show favourable outcomes in perioral volume restoration, smile design, lip support, and as adjuncts in prosthodontic and orthodontic rehabilitation. Both modalities exhibit acceptable safety profiles when administered by trained clinicians, although long term data remain limited.

Conclusion: BoNT and HA fillers represent valuable adjunctive tools in modern dental practice, supporting both functional rehabilitation and aesthetic optimisation. Their safe and effective use requires detailed anatomical knowledge, structured training, and adherence to evidence based protocols. Future research should prioritise standardised guidelines, long term outcomes, and integration with regenerative and digital dentistry.

Key Points

• Botulinum toxin provides neuromuscular modulation, while hyaluronic acid restores soft tissue volume and support
• Applications extend beyond aesthetics to include functional conditions such as bruxism and temporomandibular disorders
• Evidence is increasing but remains heterogeneous, highlighting the need for standardised clinical protocols
• Appropriate training, detailed anatomical knowledge, and adherence to regulatory guidance are essential for safe practice
• Future roles include regenerative and bioengineering applications

Keywords

Botulinum toxin; Hyaluronic acid; Temporomandibular disorders; Bruxism; Orofacial pain; Facial aesthetics; Prosthodontics; Orthodontics

Introduction

Orofacial disorders such as temporomandibular disorders (TMD), bruxism, and chronic orofacial pain represent a significant clinical burden and are now understood as multifactorial conditions involving peripheral nociception, central sensitisation, biomechanical factors, and psychosocial influences [1-6]. TMD affects approximately 5-12% of the population and encompasses muscular, joint related, and mixed presentations [7]. Bruxism is increasingly conceptualised as a behaviour rather than a disorder, reflecting its complex regulation by central and peripheral pathways [4, 8]. Orofacial pain syndromes, including myofascial pain and persistent dentoalveolar pain disorder, involve sensitisation processes that complicate diagnosis and management [5, 6, 9].

Alongside these functional conditions, the aesthetic and biomechanical roles of the perioral soft tissues have gained prominence in orthodontics, prosthodontics, and restorative dentistry. Facial aesthetics, smile dynamics, and soft tissue balance influence both oral function and psychosocial wellbeing, and are increasingly integrated into comprehensive treatment planning [10–13].

Global policy frameworks, including the FDI Vision 2030 initiative, emphasise person centred, minimally invasive, and integrated oral healthcare [14, 15]. Professional bodies such as the American Dental Association, British Dental Association, and European Society of Cosmetic Dentistry recognise the expanding role of dentists in orofacial medicine and facial aesthetics, provided appropriate training and competency standards are met [16-18].

Within this evolving clinical landscape, botulinum toxin (BoNT) and hyaluronic acid (HA) fillers have emerged as adjunctive modalities that complement conventional dental therapies. BoNT provides reversible neuromuscular modulation, while HA fillers restore soft tissue volume and structural support. These mechanisms allow clinicians to address both functional and aesthetic dimensions of orofacial health, supporting interdisciplinary approaches to patient care.

Methods

A narrative review methodology was used to synthesise current evidence on the use of botulinum toxin (BoNT) and hyaluronic acid (HA) fillers in dentistry. Literature published between 1995 and 2025 was identified through MEDLINE, PubMed, EMBASE, Scopus, and the Cochrane Library. Search terms included botulinum toxin, hyaluronic acid, temporomandibular disorders, bruxism, orofacial pain, facial aesthetics, prosthodontics, and orthodontics. Priority was given to systematic reviews, randomised controlled trials, consensus statements, and high quality clinical studies. Reference lists of key publications were manually screened to ensure comprehensive coverage. No new references were added beyond those in the original manuscript.

Mechanisms of Action

Botulinum Toxin

Botulinum toxin type A (BoNT A) exerts its therapeutic effect by inhibiting acetylcholine release at the neuromuscular junction through cleavage of the SNAP 25 protein, resulting in reversible chemo denervation and reduced muscle contractility [19]. This mechanism underpins its use in conditions characterised by excessive masticatory muscle activity, including bruxism, masseter hypertrophy, and muscular temporomandibular disorders (TMD) [3, 20, 24]. Clinical effects typically develop within several days and persist for 3-6 months, corresponding to synaptic regeneration and restoration of neuromuscular transmission [3].

BoNT also modulates nociceptive pathways by inhibiting the release of pain related neuropeptides such as substance P, glutamate, and calcitonin gene related peptide (CGRP), contributing to reductions in peripheral sensitisation and neurogenic inflammation [20]. These effects are relevant in chronic orofacial pain states, where central sensitisation contributes to symptom persistence [5, 6]. Additional autonomic influences, including modulation of microvascular perfusion, have been described in neurological applications and may contribute to its analgesic profile [21, 22].

Hyaluronic Acid Fillers

Hyaluronic acid (HA) fillers are hydrophilic, viscoelastic biomaterials that integrate within the extracellular matrix (ECM) to restore soft tissue volume, enhance hydration, and improve structural support [23]. Their rheological properties—such as elasticity, cohesivity, and viscosity—allow tailored application across the perioral region, contributing to improved lip competence, facial balance, and smile aesthetics [23, 29, 33].

HA fillers also stimulate fibroblast activity, promote neo collagenesis, and modulate ECM turnover, supporting their emerging role in regenerative and reconstructive dental applications [23]. These properties are particularly relevant in prosthodontics, where soft tissue support influences denture stability and facial proportions [25, 26]. In orthodontics and smile design, HA fillers may assist in optimising soft tissue contours and enhancing aesthetic outcomes, complementing tooth based interventions [10, 12].

Table 1. Mechanisms of Action of BoNT and HA Fillers

Clinical Applications

Temporomandibular Disorders (TMD)

Temporomandibular disorders (TMD) comprise a spectrum of conditions affecting the temporomandibular joints, masticatory muscles and associated structures, with prevalence estimates of 5-12% [7]. Muscular TMD, particularly myofascial pain, is characterized by hyperactivity of the masseter and temporalis muscles and increased peripheral sensitization [5, 6].

Botulinum toxin (BoNT) has been investigated as an adjunctive therapy due to its ability to reduce acetylcholine-mediated muscle contraction and modulate nociceptive signaling [3, 20]. Evidence suggests symptomatic improvement in selected patients, particularly those with refractory muscular pain, although outcomes remain variable due to heterogeneity in diagnostic criteria and treatment protocols [7, 20].

Hyaluronic acid (HA) fillers do not directly address intra-articular TMD pathology. However, by restoring perioral soft tissue support and improving facial balance, they may indirectly influence muscular recruitment patterns within the stomato-gnathic system [10, 23].

Bruxism

Bruxism is defined as repetitive masticatory muscle activity involving clenching, grinding or bracing of the mandible. It is now conceptualized as a behaviour rather than a disorder, reflecting its complex central and peripheral regulation [4, 8]. Etiological factors include central nervous system activity, psychosocial stress and sleep-related mechanisms [9].

Conventional management strategies such as occlusal splints and behavioural therapy demonstrate variable efficacy and do not consistently reduce muscle hyperactivity [3]. BoNT has therefore been explored as an adjunctive treatment option, with evidence demonstrating reductions in electromyographic activity, muscle pain and symptoms such as jaw fatigue and morning stiffness [3, 20]. However, its effects are temporary and do not address underlying behavioral or central mechanisms [4].

HA fillers have no proven direct therapeutic role in bruxism.

Masseter Hypertrophy

Masseter hypertrophy may arise from parafunctional activity, genetic predisposition or increased masticatory loading [24]. BoNT induces dose-dependent muscle atrophy through neuromuscular blockade, resulting in reduced muscle thickness and improvement in lower facial contour [24]. This makes it a widely accepted minimally invasive alternative to surgical reduction in selected cases.

Functional benefits may include reduction in occlusal force and alleviation of muscle-related discomfort; however, excessive weakening must be avoided to preserve masticatory efficiency.

HA fillers are not indicated for masseter hypertrophy but could be used as a camouflage for the opposite side, if need be.

Orofacial Pain Syndromes

Orofacial pain encompasses musculoskeletal, neuropathic and idiopathic conditions, including myofascial pain, persistent dentoalveolar pain disorder and referred pain from masticatory structures [5, 9]. These conditions frequently involve both peripheral and central sensitization mechanisms [5, 6].

BoNT may provide symptomatic relief through inhibition of nociceptive mediators such as substance P, glutamate and calcitonin gene-related peptide (CGRP) [20]. Its established use in neurological pain conditions, including chronic migraine, further supports its relevance in overlapping orofacial pain pathways [21, 22].

HA fillers have no proven direct role in the management of orofacial pain.

Orofacial Dystonias

Oromandibular dystonia is a movement disorder characterized by involuntary, repetitive muscle contractions affecting mastication, speech and facial expression [27]. BoNT is considered first-line therapy due to its targeted neuromuscular inhibitory effect and predictable clinical response [27]. Treatment requires specialist anatomical knowledge and careful muscle mapping to avoid functional impairment.

HA fillers have no proven therapeutic role in dystonia.

Excessive Gingival Display (“Gummy Smile”)

Excessive gingival display may result from vertical maxillary excess, altered passive eruption or hyperactivity of upper lip elevator muscles [11]. Botulinum toxin (BoNT) provides a minimally invasive option in cases predominantly driven by muscular hyperactivity by reducing upper lip elevation during smiling [27].

Although BoNT does not address skeletal or dental etiologies, it offers a reversible and adjustable treatment modality in selected patients. Hyaluronic acid (HA) fillers may serve as an adjunct in smile aesthetics by enhancing lip volume and contour, thereby reducing gingival exposure in mild cases [23, 33].

Perioral Ageing and Smile Esthetics

Age-related changes in the perioral region include loss of soft tissue volume, reduced elasticity and altered muscle tone, all of which significantly affect facial aesthetics and dental presentation [28-30]. HA fillers restore lost volume, improve lip support and enhance perioral contour, contributing to improved smile aesthetics and facial harmony [23, 33].

These changes are particularly relevant in prosthodontics and orthodontics, where soft tissue appearance plays a key role in treatment outcomes [10, 12].

BoNT has a limited role in perioral ageing but may be used to modulate hyperactive perioral muscles contributing to dynamic wrinkles.

Prosthodontics and Edentulism

In edentulous patients, loss of teeth and alveolar bone leads to reduced lip support, altered facial proportions and functional impairment [25]. HA fillers may serve as an adjunct to prosthodontic rehabilitation by restoring perioral volume, improving lip competence and enhancing denture aesthetics and function [25, 26].

BoNT has no direct role in edentulous rehabilitation. Using BoNT for active tongue thrusts and active fraenums to increase stability of prostheses and dentures is an area that needs further investigation.

Orthodontics and Soft tissue Integration

Orthodontic outcomes are influenced not only by tooth position but also by soft tissue characteristics such as lip thickness, posture and mobility [10, 12]. HA fillers may contribute to soft tissue optimization in selected cases by improving facial balance and smile aesthetics [12].

BoNT may be used selectively to modulate hyperactive perioral muscles that interfere with orthodontic stability. Using BoNT intra-dentally for the periodontal fibers to reduce potential relapse dentures is an area that needs further investigation.

Based on the above, it should be noted that BoNT and hyaluronic acid fillers have evolved beyond purely aesthetic tools into multifunctional therapeutic and bioengineering agents within dentistry and maxillofacial practice.

• Botulinum toxin primarily acts through neuromuscular modulation, enabling pain control, functional rehabilitation, and protection of surgical outcomes.
• Hyaluronic acid fillers function as structural scaffolds and regenerative matrices, supporting both soft tissue reconstruction and emerging biomaterial-based therapies.

While many applications are now well established in specialist practice, a significant proportion remain emerging, investigational, or translational, highlighting the need for standardised protocols, long-term clinical trials, and integration with regenerative and digital dentistry frameworks.

Table 2. Clinical Applications of BoNT and HA Fillers

Safety considerations

Botulinum toxin

Botulinum toxin (BoNT) has an established safety profile when administered by trained clinicians. Most adverse effects are local, transient and dose dependent, including mild pain, bruising, oedema and temporary asymmetry [3]. Functional side effects may include transient reductions in bite force or altered chewing efficiency due to reversible chemo-denervation [20]. Diffusion into adjacent muscles may cause unintended weakness, such as smile asymmetry or lip incompetence [27].

Systemic complications are exceedingly rare at dental dosing regimens.

Hyaluronic Acid Fillers

Hyaluronic acid (HA) fillers are widely regarded as safe when administered with appropriate anatomical knowledge. Common adverse effects include swelling, erythema, tenderness and mild asymmetry [23, 33]. Intermediate complications include nodularity or uneven distribution.

The most serious complication is vascular compromise due to intravascular injection or external compression. High-risk zones in the perioral region require particular caution, and early recognition is critical [31].

Delayed inflammatory reactions may occur weeks or months after treatment

Contraindications

For BoNT, absolute contraindications include hypersensitivity to botulinum toxin and active infection at the injection site. Relative contraindications include neuromuscular disorders, pregnancy and breastfeeding [19].

For HA fillers, absolute contraindications include active infection and hypersensitivity to hyaluronic acid or excipients. Relative contraindications include pregnancy, breastfeeding, autoimmune disease activity and unstable systemic inflammatory conditions [31].

Ethical considerations

The integration of injectable therapies into dentistry introduces important ethical responsibilities. Informed consent must include a clear explanation of risks, benefits, limitations and alternatives. Clinicians must avoid overtreatment and ensure interventions are justified by clinical indication rather than patient demand. Recognition of psychological conditions such as body dysmorphic disorder is essential [31].

Competency-based training and adherence to professional guidelines are critical to maintaining patient safety.

Regulatory framework

Regulation varies internationally. In the United Kingdom, dentists may perform facial aesthetic procedures provided they demonstrate appropriate training and comply with General Dental Council guidance [17]. In the United States, regulation varies by state, with many jurisdictions permitting dentists to administer injectables following certification [16]. Across the European Union, facial aesthetic practice within dentistry is widely accepted but varies in regulatory structure. The European Society of Cosmetic Dentistry promotes standardisation [18].

Discussion

The integration of botulinum toxin (BoNT) and hyaluronic acid (HA) fillers into dental practice reflects the broader evolution of minimally invasive, biologically informed approaches to orofacial care. Their combined functional and aesthetic roles align with contemporary models of patient centred dentistry, where oral health, facial balance, and psychosocial wellbeing are considered interdependent components of treatment planning [10-13].

TMD, bruxism, and chronic orofacial pain are complex conditions influenced by peripheral nociception, central sensitisation, and behavioural factors [1–6]. Within this context, BoNT offers a targeted means of reducing excessive muscular activity and modulating nociceptive pathways, supporting its use as an adjunctive therapy in selected muscular TMD phenotypes, bruxism, masseter hypertrophy, and myofascial pain [3, 20, 24]. Its reversible neuromuscular effects complement conventional therapies rather than replacing them.

HA fillers contribute to orofacial rehabilitation through their capacity to restore soft tissue volume, enhance lip support, and improve perioral contour. These effects are relevant not only in aesthetic dentistry but also in prosthodontics, orthodontics, and edentulous rehabilitation, where soft tissue balance influences oral function, denture stability, and smile dynamics [23, 25, 26, 29, 33]. Their regenerative potential represents an emerging area of interest within restorative and reconstructive dentistry [23].

Safety remains a critical consideration. BoNT is generally well tolerated, with adverse effects typically mild and transient [3]. HA fillers also demonstrate a favourable safety profile, although the risk of vascular compromise underscores the need for detailed anatomical knowledge and prompt management protocols [31]. Competency based training, adherence to evidence based guidelines, and careful patient selection are essential to minimise complications.

Despite increasing clinical adoption, the evidence base for BoNT and HA fillers in dentistry remains heterogeneous. Variability in study design, diagnostic criteria, injection protocols, and outcome measures limits comparability across studies [7, 8]. Long term data are scarce, and combined BoNT-HA treatment protocols require further investigation.

Future research should prioritise standardised methodologies, robust clinical trials, and interdisciplinary collaboration to clarify optimal indications, refine treatment protocols, and evaluate long term outcomes.

Conclusion

Botulinum toxin (BoNT) and hyaluronic acid (HA) fillers have become valuable adjuncts within contemporary dental practice, supporting both functional rehabilitation and aesthetic optimisation. BoNT provides reversible neuromuscular modulation and demonstrates clinical benefit in conditions characterised by excessive masticatory muscle activity, including bruxism, masseter hypertrophy, muscular temporomandibular disorders, and selected orofacial pain presentations [3, 20, 24]. HA fillers restore soft tissue volume, enhance lip support, and improve perioral contour, contributing to improved smile aesthetics and supporting prosthodontic, orthodontic, and edentulous rehabilitation [23, 25, 26].

Both modalities exhibit favourable safety profiles when administered by clinicians with appropriate anatomical knowledge and training. Their effects are temporary and adjunctive, reinforcing the importance of integrating these therapies within comprehensive, evidence based treatment plans. Ethical practice requires informed consent, careful patient selection, and adherence to regulatory and professional standards [31].

Although clinical adoption continues to expand, current evidence remains limited by heterogeneity in study design, diagnostic criteria, and outcome measures. Future research should prioritise standardised methodologies, robust clinical trials, and interdisciplinary collaboration.

References

1. Sessle B J. Acute and chronic craniofacial pain: brainstem mechanisms of nociceptive transmission and neuroplasticity, and their clinical correlates. Crit Rev Oral Biol Med 2000; 11: 57–91.
2. Schiffman E, Ohrbach R, Truelove E et al. Diagnostic criteria for temporomandibular disorders (DC/TMD) for clinical and research applications. J Oral Facial Pain Headache 2014; 28: 6–27.
3. Guarda Nardini L, Manfredini D, Salamone M, Salmaso L, Tonello S, Ferronato G. Efficacy of botulinum toxin in treating myofascial pain in bruxers: a controlled clinical trial. CRANIO 2008; 26: 126–135.
4. Lobbezoo F, Ahlberg J, Raphael K G et al. International consensus on the assessment of bruxism: report of a work in progress. J Oral Rehabil 2018; 45: 837–844.
5. Woolf C J. Central sensitisation: implications for the diagnosis and treatment of pain. Pain 2011; 152: S2–S15.
6. Latremoliere A, Woolf C J. Central sensitisation: a generator of pain hypersensitivity by central neural plasticity. J Pain 2009; 10: 895–926.
7. Ohrbach R, Dworkin S F. The evolution of TMD diagnosis: past, present, future. J Dent Res 2016; 95: 1093–1101.
8. Manfredini D, Winocur E, Guarda Nardini L, Paesani D, Lobbezoo F. Epidemiology of bruxism in adults: a systematic review. J Oral Facial Pain Headache 2013; 27: 99–110.
9. Benoliel R, Sharav Y. Persistent orofacial pain. In Sharav Y, Benoliel R (eds) Orofacial Pain and Headache. pp 91–112. Edinburgh: Elsevier, 2015.
10. Sarver D M. The importance of facial aesthetics in orthodontics. Am J Orthod Dentofacial Orthop 2001; 120: 465–467.
11. Polo M. Botulinum toxin type A in the treatment of excessive gingival display. Am J Orthod Dentofacial Orthop 2008; 133: 195–203.
12. Ackerman J L, Proffit W R. Soft tissue limitations in orthodontics: treatment planning guidelines. Angle Orthod 1997; 67: 327–336.
13. Peck S, Peck L, Kataja M. The gingival smile line. Angle Orthod 1992; 62: 91–100.
14. FDI World Dental Federation. FDI Vision 2030: delivering optimal oral health for all. Geneva: FDI World Dental Federation, 2021.
15. Watt R G, Daly B, Allison P et al. Ending the neglect of global oral health: time for radical action. Lancet 2019; 394: 261–272.
16. American Dental Association. Policy on the use of botulinum toxin and dermal fillers by dentists. Chicago: American Dental Association, 2016.
17. General Dental Council. Scope of practice. London: General Dental Council, 2013.
18. European Society of Cosmetic Dentistry. ESCD guidelines for facial aesthetics in dentistry. Vienna: European Society of Cosmetic D