Accuracy of Intentional Change of Frontal Ramal Inclination From Virtual to Actual Orthognathic Surgery Using Computer-Aided Design and Computer-Aided Manufacturing-Made Customized Metal Plates.

OBJECTIVE: To evaluate the accuracy of intentional change of the frontal ramal inclination (FRI) from virtual to actual orthognathic surgery. MATERIALS AND METHODS: A total of 16 patients who underwent orthognathic surgery for correction of facial asymmetry and took cone-beam computed tomography 2 to 3 weeks before surgery (T0) and 3 days after surgery (T1A) were selected. After reorientation of cone-beam computed tomography, the digital imaging and communications in medicine data was converted to StereoLithography format for the merging with dental cast scan using R2GATE software (MegaGen Implant, Daegu, Republic of Korea). During virtual surgery using Geomagic Freeform Plus software (3D Systems, Rock Hill, SC), bilateral FRI discrepancy was corrected (T1V) and 3D-printed surgical wafers and customized metal plates were manufactured using 3D printer (Meg-printer II, MegaGen Implant, Daegu, Republic of Korea) and computer numerical control milling machine (ARDEN, TPS Korea Ltd., Gwangju, Republic of Korea) accordingly. During surgery, FRI correction was done using surgical guide and customized plates. The difference between preoperative and virtually corrected FRI (Δ T1V - T0) and the difference between preoperative and actually surgically corrected FRI (Δ T1A - T0) were measured, and the achieved FRI correction in percentage ([Δ T1A - T0]/[Δ T1V - T0] × 100) was calculated. RESULTS: The mean absolute value of virtual FRI correction (Δ T1V - T0) and actual FRI correction (Δ T1A - T0) were 3.0° and 2.9°, respectively (n = 32). In the increased (medial rotation) FRI group, mean virtual and actual correction amount were 3.2° and 2.8° (n = 17), whereas in the decreased (lateral rotation) group, mean virtual and actual correction amount were -2.7° and -3.1°, respectively (n = 15). No statistically significant difference between virtual and actual measurements were present in either group. The mean achievement rate was 102.8%. Tendency of undercorrection (91.2%) in the increased FRI group and overcorrection (116.0%) in the decreased FRI group were noted. DISCUSSION: With virtual planning and computer-aided design and computer-aided manufacturing-made customized plates, it is possible to correct FRI during orthognathic surgery of patients with facial asymmetry.

Surgical ciliated cyst of the mandible after orthognathic surgery: a case report with review of the literature.

BACKGROUND: Surgical ciliated cysts, also known as postoperative maxillary cysts or implantation cysts, occur mainly in the posterior maxilla after radical maxillary sinus surgery; they rarely develop in the mandible. They are thought to occur when the sinonasal epithelium is infiltrated by a surgical instrument during surgery or as a result of transplantation of bone or cartilage with respiratory epithelium attached. CASE PRESENTATION: We report a case in which a surgical ciliated cyst developed in the anterior part of the mandible, presumably as a result of bimaxillary orthognathic surgery and genioplasty performed 24 years earlier. We then review the few similar cases reported in the literature. CONCLUSION: Surgical ciliated cysts in the mandible are extremely rare, but they could occur after simultaneous surgery on the maxilla and mandible, even decades later. To prevent surgical ciliated cysts in the mandible, we recommend that the surgical instruments, especially the saw blade used during bimaxillary surgery, be new or cleaned and that previously placed plates and screws be removed at an appropriate time.