Study On The Measurement Of Bone Defect Volume In Unilateral Alveolar Cleft

Objective:Alveolar cleft repair is part of the cleft lip and palate sequence treatment.It is important to measure the volume of the maxillary defect before the alveolar cleft repair.Currently,the preoperative three-dimensional CT shows the bone defect of the alveolar cleft palate.However,the calculation of the bone defect volume is very difficult due to the irregular nature of the alveolar cleft.This study aims to explore the method for volumetric measurement of alveolar bone defect.Methods:3D printing technology can construct a 1:1 solid model of the maxillary by layering the material,simulate the alveolar cleft repair surgery on the model,and directly measure the required graft volume.In addition,the volume of bone defects can also be calculated by computer-aided engineering systems.This study applied 2 advanced preoperative volume measurement methods:three-dimensional(3D)printing and computer-aided engineering(CAE).Twenty-six unilateral alveolar cleft patients were enrolled in this study from April 2015 to December 2016.Their computed tomographic data were sent to 3D printing and CAE software.A simulated graft was used on the 3D-printed model,and the graft volume was measured by water displacement.The volume calculated by CAE software used mirror-reverses technique.Results:The volume of alveolar bone defect could be detected by both methods.The average volume of the simulated bone grafts by 3D-printed models was 1.61 ml,a little higher than the mean volume of 1.60 calculated by CAE software.The difference between the 2 volumes was from-0.34 ml to 0.54 ml.The paired Student t test showed no statistically significant difference between the volumes derived from the 2 methods.Conclusions:This study demonstrated that the volume of alveolar bone defect is about 1.6ml in unilateral alveolar cleft patients aged 9-12 years.the mirror-reversed technique by CAE software is as accurate as the simulated operation on 3D-printed models.These findings further validate the use of 3D printing and CAE technique in alveolar defect repairing.