[An ultrastructure study on the palatomaxillary suture of dog expanded by NiTi-SMA].
OBJECTIVE
To explore the ultrastructure of the palate-maxillary sutures under tensile forces by transmission electron microscope (TEM).


METHODS
The Suture expanders were made in NiTi-Shape memory alloy (NiTi-SMA). The maximum force was 3.5 N. Fourteen 8-month old mongrel dogs were used in the study. They were divided into three groups, (1) experimental group, (2) control group, (3) sham group. In the experiment and control groups, an 8 mm wide cleft was made by surgery. The suture expanders were fixed onto the palatine bones of the experimental group. The dogs of the experimental group were executed after 3, 7, 14, 28, 56 days of suture expansion. The change of suture tissue was examined by TEM.


RESULTS
The cleft of the experiment group were closed at the ninth day of expansion. At the beginning, tissue rupture, exudation, death of fibroblasts, disruption of collagen and tear vessels were seen at the early stage of suture expansion. Then highly active functional manifestations were seen in both osteocytic and fibrocytic populations. At last, normal structure restored.


CONCLUSIONS
Cell types and functional condition could be distinguished clearly by TEM. It suggests that the suture expansion should be the process of tissue repair and regeneration. The suture cells response, especially, the osteogenic response were the major factor of increasing suture width.
Gao
Quan-Wen
QW
Department of Burn and Plastic Surgery, the First Hospital Affiliated of General Hospital of PLA, Beijing 100037, China.
Chai
Jia-Ke
JK
Song
Hui-Feng
HF
Xu
Ming-Huo
MH
Jing
Sa
S
Liu
Chun-Ming
CM
D000497:Alloys; D000818:Animals; D001861:Bone Regeneration; D003393:Cranial Sutures / Q000601:surgery; D004285:Dogs; D008437:Maxilla / Q000601:surgery / Q000648:ultrastructure*; D046529:Microscopy, Electron, Transmission; D009532:Nickel; D010012:Osteogenesis; D019857:Osteogenesis, Distraction; D021362:Palate, Hard / Q000601:surgery / Q000648:ultrastructure*; D013718:Tensile Strength; D014025:Titanium
D000497:Alloys; D009532:Nickel; D014025:Titanium