[Effects of strontium ranelate on the rats' palatal suture after rapid maxillary expansion].
OBJECTIVE
This study investigated the effects of strontium ranelate (SrR) on the rats' palatal suture after rapid maxillary expansion (RME).


METHODS
Thirty-six male 6-week-old Wistar rats were randomly divided into three groups: control group (A), expansion only group (B), and expansion plus SrR group (C). Each group comprised 12 rats. Neither expansion nor SrR was given to group A. Each rat in groups B and C was set an orthodontic appliance with an initial expansive force of 1 N. The rats in group C were administered with SrR (600 mg·kg⁻¹ body weight) at the same time every day after RME. All the rats were then euthanized in batches on days 4, 7, and 10. The width of the rats' upper jaw was measured. Histological observation was used to section the rats and count the osteoblasts.


RESULTS
After the RME, no statistical difference was observed on the rats' upper jaw width in group A (P>0.05). However, the change of upper jaw width in groups B and C presented a statistical significance (P<0.05). By contrast, no statistical difference was observed between groups B and C (P>0.05). The rats' sections were placed under a microscope, and some red fibrous tissues, mesenchymal cells, chondrocytes, and osteoblasts were observed in group A. More red fibrous tissues, mesenchymal cells, and chondrocytes were observed in groups B and C. In addition, more osteoblasts were observed on the edge of mid-palatal suture of the rats. Group C contains more osteoblasts than group B.


CONCLUSIONS
RME can expand the mid-palatal suture of rats, which were in the growth development period, and increase the width of dental arch. SrR may promote osteoblast differentiation and hasten new bone formation in the expanded mid-palatal suture. Both conditions accelerate new bone formation and bone deposition calcification, which may be therapeutically beneficial to prevent relapse after RME.
Dept. of Orthodontics, School of Stomatology, Shandong University, Jinan 250012, China.
Kong
K
Chao
Dept. of Oral and Maxillofacial Surgery, School of Stomatology, Shandong University, Jinan 250012, China;Key Laboratory of Oral Tissue Regeneration of Shandong Province, Jinan 250012, China.
Wang
W
Xuxia
Dept. of Orthodontics, School of Stomatology, Shandong University, Jinan 250012, China.
Wang
W
Qianqian
Dept. of Orthodontics, School of Stomatology, Shandong University, Jinan 250012, China.
Han
H
Yuanyuan
Dept. of Orthodontics, School of Stomatology, Shandong University, Jinan 250012, China.
Zhao
Z
Shuya
Dept. of Orthodontics, School of Stomatology, Shandong University, Jinan 250012, China;Key Laboratory of Oral Tissue Regeneration of Shandong Province, Jinan 250012, China.
Zhang
Z
Jun
D000818:Animals; D002454:Cell Differentiation; D008297:Male; D008437:Maxilla; D010006:Osteoblasts; D010012:Osteogenesis; D010155:Palatal Expansion Technique; D010159:Palate; D051381:Rats; D017208:Rats, Wistar; D013537:Sutures; D013876:Thiophenes
D013876:Thiophenes; C081587:strontium ranelate
osteoblasts; rapid maxillary expansion; strontium ranelate