Study Of Rhesus Monkey's Craniomaxillary Structure Width

[Objectives]The study was made to observe the width changes of upper-lower dental arch,alveolar bone and cranio-facial structure of rhesus monkeys under retractive force with zygomatic implant anchorage by means of model analysis and spiral CT finding,further to evaluate the effects of backward traction to the maxillary.[Methods]4 young male rhesus monkeys were employed,3 experimented(1 for 1.5 month and 2 for 3 months) and 1 as control.Two titanium miniplates were surgically fixed on the left and right zygomatic bones as an anchorage for backward traction of maxillary for each experimented monkey.A NiTi closure coil was attached to the miniplate and maxillary dental splint on each side.A retractive force of 150g was exerted on each side with a direction qarallel to an occlusal plane.Model measurement and the spiral CT three-dimension reconstruction were analysed between the beginning and the end of experiment.[Result]l.Model measurement:There was no significant difference of each measurement item of control group and 1.5 months experimented group(p＞0.05).The posttreatment widths of upper dental arch and alveolar bone,and lower dental arch and alveolar bone were increased.However,the changes of upper alveolar bone and lower dental arch had significant difference(p＜0.05).2.Spiral CT three-dimensional reconstructiou finding:There was no distinct changes of Ro-Ro',Lo-Lo',Ore-Ore', Cd-Cd',Go-Go' between control group and experimented group.With exerting retractive force,the changes of Zyg-Zyg',Max-Max',Nas-Nas' were increased.The experimented groups' Uc-Uc' and U6-U6' were also increased,more significantly difference 1.5 month groups than 3 month groups.The experimented groups' Lc-Lc' and L6-L6' were increased,then more significantly difference 3 months groups than 1.5 months groups.[Conclusion]1.The widths of rhesus monkeys' upper alveolar bone and lower dental arch were increased under the retractive force with zygomatic implant anchorage.2.Withs exerting backward traction,there was a obvious change in rhesus monkeys' midface structure.Increasing tendency was observed in rhesus monkeys' widths of zygomatic arch,maxilla basal bone and nasal part.