The current study sought to determine the reliability of the rehabilitation protocol using the labial commissure angle (LCA) as an indicator of both muscle tonus and therapeutic success. The investigators hypothesized that this measurement would provide objective data regarding the efficacy of rehabilitation for these challenging patients.

CONTEXT AND OBJECTIVE: In cases of peripheral facial paralysis (PFP), diminished facial movements and their resultant cosmetic sequelae may have significant emotional repercussions, in addition to producing pronounced functional deficits. Abnormal muscle proprioception and deviation of the nasal-labial filter may also interfere with articulation of the labiodental and bilabial phonemes, thus diminishing speech intelligibility. In relation to stomatognathic functions, weakened labial occlusion decreases intraoral pressure, thereby hindering liquid retention in the buccal cavity and giving rise to vestibular stasis on the paralyzed side. The aim of this study was to evaluate the reliability of the labial commissure angle (LCA) as an anthropometric marker for objectively assessing changes in facial muscle tonus.

Inclusion Criteria:

• age range between 20 and 70 years
• incomplete PFP (Degree IV)
• integral facial nerve (FN)

Exclusion Criteria:

• systemic disease
• potentially aggravating the PFP (neurological, degenerative, endocrinological)

Patients diagnosed with PFP treated in the Hospital of Unicamp