The role of orthognathic surgery in the correction of dento-skeletal dysmorphies, whether they are Class II or Class III or asymmetries, is to improve both the function and aesthetic appearance of thepatient. Both aspects are equally important to achieve optimal results.
When the surgeon plans the surgery, he or she must therefore take into account the effects that bone displacements will have at the level of the soft tissues directly involved in the surgery, such as the maxilla and mandible. Traditionally, such surgery consists of an orthodontic presurgical phase1,2
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Patients undergoing orthognathic surgery and preoperative radiographic study with CBCT and MRI
Patients with age > or = 18 years old
Obtaining informed consent
Patients with preoperative teleradiography and orthopantomography
patients with cleft lip-palate, facial malformations and/or syndromes (syndromes with involvement of the cephalic extremity, such as sd of Apert. Cropuzon, Ofeiffer, Treacher Collins)
patients who have undergone application of Medpor prostheses or who have undergone ancillary procedures (lipofilling, fillers, volumetric facial augmentations with insertion of polyethylene ketone prostheses)
Verranno arruolati 10 pazienti retrospettivamente. Per ogni paziente verranno effettuate 27 simulazioni virtuali variando le proprietà biomeccaniche delle singole parti. I dati verranno perciò analizzati su 270 interventi virtuali. Le 27 simulazioni procapite vengono determinate in base al range di variazione che in fase iniziale si decide di dare ai vari parametri biomeccanici presi in considerazione per ogni componente del modello (tessuti molli, muscoli, osso)14 . Un campione di 270 simulazione, consente di avere un intervallo di confidenza di 7.85 e un livello di confidenza del 99%. La tabella di seguito dimostra i valori massimi e minimi dati ai singoli muscoli per quanto riguarda il modulo di Young o modulo di elasticità.
Cohort
Retrospective
Not listed
primary outcomes
Implementation of a virtual three-dimensional model of the face already provided for care procedure that is anatomically accurate in predicting soft tissue displacements following orthognathic surgery. This model will include the biomechanical characteristics of the facial muscles and skin. In particular, the sensitivities of different areas of the face (nose, cheeks, and upper lip) that are particularly important in orthognathic surgery will be evaluated in response to variation in the biomechanical properties of the muscles (Poisson's coefficient and Young's modulus).
secondary outcomes
Demonstrate whether the inclusion of anatomical details such as facial muscles improves virtual prediction by comparing the simulation model with what is obtained in reality. This comparison will be made by superimposing the 3D object obtained from the virtual soft tissue simulation with the 3D soft tissue object obtained from postoperative CBCT. Through a colorimetric scale ranging from - to + 5 mm, we will evaluate the distance between the 3D reconstruction actually obtained from the patient's postoperative CBCT and the virtual simulation of the anatomically complex model.
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