ABSTRACT
Objective@#To calculate the three-dimensional trajectory and motion morphology of condyle by combining the trajectory of the mandible movement and the three-dimensional model of the mandible.@*Methods@#Cone beam CT (CBCT) scanning was performed on the volunteer. The mandible three-dimensional model was built with image data transferred to the graphical user interface of the computer workstation. The novel virtual articulator PN300 recorded the three-dimensional trajectory of mandible. All these data were transferred to software system of computer workstation calculating the three-dimensional trajectory of condyle. The motion morphology of condyle was simulated by merging function surface at each point.@*Results@#When the mandible moved in an opening process, the recorded data was calculated and it was shown that: the condylar functional surface moved moved forward and downward inward in advance, and in the process of continuously increasing the opening degree, the function faced the front upper inner side. The straight-line distance between the position and the final position was 8.34 mm. During the forward movement of the mandible, the coracoid process slided forward downward and inward with a sliding distance of 8.64 mm. During lateral movement, the range of the working side condyle function surface motion was small, only slight rotation, the maximum range of motion was 1.97 mm; in the process of row side movement, the non-working condyle function surface had a larger movement range than the working side, the movement direction was the front lower inner side, and the movement distance was 7.65 mm.@*Conclusions@#The novel virtual articulator PN300 and digital technology can achieve the accurate measurement of three-dimensional trajectory of the condyle, and furthermore simulate the motion morphology of the condyle.
ABSTRACT
Objective:To test the periodontal regeneration potential after tooth root replantation combined with in vitro cultured periodontal ligament cells (PDLCs).Methods:The third and fourth mandibular premolars of two mongrel dogs were extracted and the dog PDLCs were in vitro cultured.The autologous roots combined with PDLCs were replanted into the created cavities in the right mandibular edentulous area one month after premolar extraction.Roots replanted without PDLCs on the left mandible served as the controls. The dogs were sacrificed 2 months after the replantation. Paraffin sections were made and stained with hematoxylin & eosin, then examined histologically.Results:In the samples of root combined with PDLCs implantation, some fiber bundles vertical to the surface of bone were embedded in some inner walls of the alveolar socket opposite to the apical root.Conclusion:Cultured PDLCs in vitro retain the capacity of PDL-like tissue formation even in the artificial alveolar socket.