Personalized Titanium Plates vs CAD/CAM Surgical Splints in Maxillary Repositioning of Orthognathic Surgery

Personalized Titanium Plates vs CAD/CAM Surgical Splints in Maxillary Repositioning of Orthognathic Surgery

A Randomized Controlled Trial of the Accuracy of Maxillary Repositioning Using Personalized Titanium Plates vs CAD/CAM Surgical Splints in Orthognathic Surgery

The purpose of this study is to determine whether personalized titanium plates can achieve better accuracy than CAD/CAM surgical splint in maxilla repositioning in orthognathic surgery, and evaluate the feasibility of this technique in clinical application.

The repositioning of maxillary segment is essential for esthetic and functional outcomes in orthognathic surgery. With the giant leap in three-dimensional (3D) computer-aided surgical simulation (CASS) technology development, surgeons are now able to simulate various surgical plans in a computer to achieve the best possible outcome. In order to transfer the virtual surgical plan to the patient at the time of the surgery, surgical splints manufactured by computer-aided design and manufacturing (CAD/CAM) technique has been traditionally used to intraoperative reposition the maxilla. Nonetheless, the position of maxilla is still dependent to mandibular autorotation. The instability of the mandibular condyle-fossa relationship is a potential problem that may directly affect the placement of the maxillary segment at the desired position. Personalized titanium plates manufactured using titanium 3D printing technique have been used for maxilla repositioning and fixation to improve the operative accuracy in orthognathic surgery. Despite this, the evidence for advantage of this personalized titanium plates technique is not very strong and based on only a few studies. The purpose of this study is to determine whether personalized titanium plates can achieve better accuracy than CAD/CAM surgical splint in maxilla repositioning in orthognathic surgery. The accuracy of using both methods for maxilla repositioning was quantitatively evaluated using linear and angular measurement. Secondary outcomes include operative time, amount of intraoperative blood loss, preoperative preparation time and treatment cost will also be measured to evaluate the feasibility of clinical application of personalized titanium plates technique in orthognathic surgery.

Personalized Titanium Plate, Orthognathic Surgery, Maxilla Repositioning, Accuracy, Computer-aided Design and Manufacturing, Patient Specified Implants (PSI)

After the LeFort I osteotomy, the intraoperative repositioning and fixation of the maxilla is accomplished using 3D printing personalized titanium plates.

After the LeFort I osteotomy, the intraoperative repositioning of the maxilla is accomplished using CAD/CAM surgical splints and the fixation of the maxilla is accomplished using commercialization titanium plates.

The cutting guides were placed onto the planned position. The cutting guides also worked as the drilling guide. Several screw holes were drilled using the predetermined screw holes on the guides. The osteotomy / ostectomy then start. Next, the 3D printing personalized maxillary fixation plates were adapted to reposition the Le Fort I segment to the planned position. The screw holes on the bones prepared by the cutting guides were used as the bony reference. The personalized plate was first firmly installed on the maxilla above the osteotomy line by aligning the corresponding screw holes on the plate to the bone. Afterwards, the position of the osteotomized Le Fort I segment was adjusted till all the remaining corresponding screw holes on bone and plate were aligned.

Three landmark points (Upper dental midline between the 2 maxillary central incisal embrasure and both side mesiobuccal cusp of the upper 1st molar) were adopted on the maxilla, and the coordinates of these three landmarks were used to calculate the centroid of the maxilla. Positional differences of the centroid of the maxilla between the virtual plan and the actual result were measured.

The translation differences of the centroid of the maxilla between the virtual plan and the actual result were calculated in X, Y and Z axis.

The coordinates of all three landmarks of the maxilla was used to calculate the differences of orientation between the plan and postoperative results, which were calculated in pitch (the rotation around the X axis), roll (the rotation around the Y axis), and yaw (the rotation around the Z axis).

Inclusion Criteria: patients who were diagnosed with skeletal dentofacial deformity and scheduled to undergo orthognathic surgery including maxillary surgery patients who were scheduled to undergo a computed tomography (CT) scan as a part of their diagnosis and treatment patients who agreed to participate in this study Exclusion Criteria: Patients who had the previous orthognathic surgery Patients who had the previous maxillary or mandibular trauma Patients who had the maxillofacial tumor Patients who required the segmental maxillary surgery Oral soft tissues defect Within the infection period Craniofacial syndromes Bone metabolism disturbance Allergic to the titanium implant Unable to give informed consent Psychiatric disorders including dementia that may interfere with the study protocol Pregnancy Included in other studies Severe craniomandibular disorders