Case Report: Digital fabrication of a music splint oral appliance for lip irritation in a brass player

Playing a brass instrument at a professional level demands immense physical endurance, precise muscle coordination, and strict physiological alignment of the orofacial structures. For a 36-year-old professional trombonist performing in jazz ensembles and teaching as a musical instructor, chronic lower-lip pain threatened to derail his decades-long career. The discomfort, brought on by dental crowding of the mandibular anterior teeth and continuous mechanical pressure from the instrument’s mouthpiece, ultimately led researchers and dental clinicians to pioneer a targeted, reversible intervention. Utilizing a combination of conventional provisional appliances and advanced digital workflows, a multidisciplinary team successfully designed and evaluated a custom music splint that alleviated the musician’s physical pain while fully preserving his acoustic and rhythmic performance capabilities.

The findings, documented in a clinical case report published in Frontiers in Psychology, highlight an innovative intersection between music dentistry and digital fabrication. Authored by researchers including Mariko Hattori and corresponding senior investigators from Institute of Science Tokyo, in partial collaboration with Yamaha Corporation, the study offers a promising clinical roadmap for wind instrumentalists suffering from performance-limiting embouchure disorders.

Background Context and Clinical Findings

The orofacial complex—encompassing the lips, tongue, teeth, and jaw—serves as the biological anchor for wind instrument performance. When a musician blows into a mouthpiece, the applied force distribution is heavily dictated by dental alignment, tooth inclination, and occlusal morphology. For brass players, the mouthpiece is forcefully pressed against the lips, compressing soft tissues directly against the mandibular and maxillary anterior teeth.

In this specific case, the patient had maintained a rigorous daily playing schedule since his junior high school years. Over the previous four years, however, he experienced progressive discomfort, localized soft-tissue irritation, and early fatigue in his lower lip during extended playing sessions. Clinical examination revealed significant crowding of the lower front teeth, a left-sided crossbite, and an edge-to-edge relationship of the right lateral incisors. While no open ulcerations were visible upon initial presentation, the chronic mechanical friction severely compromised his endurance and threatened his professional output.

Faced with these symptoms, dental professionals had to carefully weigh potential treatments. While permanent orthodontic alignment or tooth reshaping could theoretically alter the dental contours, irreversible modifications carry a high risk of permanently destabilizing a professional musician’s meticulously developed embouchure. Consequently, the clinical team prioritized a conservative, reversible approach: intraoral music splint therapy designed to act as a protective mechanical buffer between the teeth and the lower lip.

Chronology of the Clinical Intervention

The therapeutic timeline unfolded across several distinct phases, moving from conventional prototyping to advanced computer-aided design (CAD) and digital manufacturing:

• Initial Presentation and Evaluation: The 36-year-old trombonist presented with long-standing lower-lip pain linked to mandibular anterior crowding.
• Provisional Splint Fabrication: Using conventional irreversible hydrocolloid impressions and dental stone models, clinicians fabricated a provisional polyethylene terephthalate splint (1.5 mm thick) to cover the lower anterior teeth. Fitted chairside with acrylic resin, the appliance was manually shaped and polished to create a smooth labial surface.
• Provisional Testing and Feedback: The patient wore the provisional splint during regular practice, reporting an immediate reduction in lip pain, increased playing endurance, and favorable evaluations of his sound quality from peers.
• Digital Transition and CAD Design: Six months after the provisional trial, a definitive splint was engineered. A model scanner captured the successful geometry of the provisional appliance, while an intraoral scanner (TRIOS 3) mapped the patient’s dental arches. Software (Dental System) guided the digital design.
• Material Innovation and Milling: Initial attempts to mill the definitive splint solely from auto-polymerizing acrylic resin resulted in structural fractures at thin stress points. To overcome this, engineers incorporated a fiber-reinforced composite resin disk (Trinia) for structural reinforcement, bonding the components with denture base acrylic resin.
• Final Delivery and Optimization: The definitive device required minimal adjustment upon delivery. Final chairside polishing ensured optimal lip comfort, stability, and tactile feedback.

Objective Testing, Psychoacoustic Analysis, and Rhythm Stability

To scientifically validate that the music splint did not negatively impact the musician’s art, researchers deployed rigorous objective evaluations. Psychoacoustic and rhythm analyses were conducted on the same day in a soundproof environment across four distinct playing conditions: without a splint, with the provisional splint, with the definitive splint, and with the adjusted definitive splint.

Using a specialized microphone positioned 30 cm from the trombone bell and acoustic analysis software, the patient performed specified half notes at three dynamic levels: pianissimo (pp; very soft), mezzo forte (mf; moderately strong), and fortissimo (ff; very strong).

The psychoacoustic parameters of loudness and sharpness demonstrated that the expected dynamic growth patterns remained entirely intact across all conditions. Loudness scaled consistently from pp to mf to ff, and sharpness increased correspondingly. Neither the provisional nor the definitive splints induced any marked acoustic deterioration.

Furthermore, rhythm stability was measured by calculating the coefficient of variation in note duration during repeated note sequences. While the provisional splint exhibited a minor increase in rhythm variability compared to playing without an appliance, the adjusted definitive splint successfully restored rhythm stability to baseline levels identical to the unassisted condition.

Patient Perspective and Subjective Outcomes

Subjective metrics captured via visual analog scales (VAS) corroborated the objective data. The patient reported substantial improvements across multiple parameters:

• Significant reduction in lower-lip pain and mucosal irritation.
• Enhanced overall playing comfort and reduced performance-related fatigue.
• Extended daily practice durations without physical distress.
• High ratings for splint stability, ease of insertion, removal, and self-cleaning.
• Heightened confidence and alleviated performance anxiety.

In his own feedback, the patient noted that the appliance not only eliminated his physical suffering but also restored his psychological ease, allowing him to focus entirely on musical expression rather than managing physical pain.

Implications for Music Dentistry and Future Research

This case report underscores the growing clinical value of music dentistry—a specialized niche intersecting dental prosthetics, biomechanics, and performing arts medicine. Historically, wind instrumentalists suffering from embouchure-disrupting dental anomalies faced limited, often invasive options that risked ruining their careers.

The successful deployment of a digitally designed, fiber-reinforced composite music splint demonstrates how modern dental technology can provide customized, precision-fit solutions. Digital workflows allow clinicians to replicate and refine successful provisional geometries with micrometric accuracy, minimizing chairside adjustment time and preserving delicate muscular habits.

Despite these promising results, the authors note several limitations inherent to single-subject case reports. The findings lack long-term longitudinal tracking across larger cohorts, and the acoustic data were derived from a single recording session per condition, precluding deep analysis of between-take variability. Future investigations must expand to include larger sample sizes, broader instrumentation (such as woodwinds and high-brass instruments), and extended follow-up windows.

Nevertheless, the integration of digital prosthodontics into performing arts healthcare offers a vital lifeline for musicians. By successfully mitigating mechanical soft-tissue trauma without sacrificing loudness, sharpness, or rhythm stability, customized music splints prove that clinical precision and artistic integrity can harmoniously coexist.