Functional and morphologic changes after combined maxillary intrusion and mandibular advancement surgery

Area of Science:

• Orthodontics and Dentofacial Surgery
• Craniofacial Morphology
• Oromotor Function

Background:

• Combined vertical maxillary excess (VME) and mandibular retrognathia present unique challenges in facial skeletal morphology.
• Patients with this deformity often exhibit deficiencies in oromotor function, impacting mastication and speech.

Purpose of the Study:

• To compare the facial morphology and oromotor function of patients with VME and mandibular retrognathia to a control group.
• To evaluate the changes in these parameters following combined maxillary intrusion and mandibular advancement surgery.

Main Methods:

• A cohort of 15 female patients with VME/retrognathia was compared to 26 female controls.
• Measurements included facial skeletal morphology, mandibular range of motion, bite force, and masticatory muscle electromyographic activity (EMG) before and up to 3 years after orthognathic surgery.
• Statistical analyses included ANOVA and t-tests for comparisons.

Main Results:

• Preoperative measurements confirmed the characteristic VME and mandibular retrognathia morphology.
• Postoperative morphologic measurements showed improvement toward normal values after maxillary elevation (2.8 mm) and mandibular lengthening (7.1 mm).
• While bite force and range of motion improved significantly after surgery, masseter mechanical advantage remained lower than controls, and motion measurements did not fully recover.

Conclusions:

• Patients with VME and mandibular retrognathia exhibit significant oromotor functional deficits.
• Combined orthognathic surgery effectively improves both morphologic and functional deficits associated with this dentofacial deformity.
• Surgical correction leads to normalization of many presurgical values, though some functional parameters may require further investigation.