Opening of circumaxillary sutures by alternate rapid maxillary expansions and constrictions.
OBJECTIVE
To analyze quantitatively the circumaxillary suture opening after alternate rapid maxillary expansions and constrictions (Alt-RAMEC).


METHODS
Twelve inbred cats were randomly grouped into two equal groups for 1 week of rapid maxillary expansion (RME) (1 mm/day) or 5 weeks of Alt-RAMEC (1 mm/day). At the end of the experiment, the craniofacial skeleton of each cat was harvested. Each circumaxillary suture was then probed at three sites with a 0.5-mm pointed periodontal probe. A smooth probing without penetration was an ineffective suture opening (<0.5 mm), while a probing with penetration was an effective suture opening (>0.5 mm). For each suture, the quantity of suture opening (%) was the effective suture opening/(effective + ineffective suture opening). The intergroup differences were analyzed by chi-square test (P < .05).


RESULTS
Five weeks of Alt-RAMEC opened the circumaxillary sutures significantly more than 1 week of RME. This affected the circumaxillary sutures running coronally and articulating directly to the maxilla (56.9% vs 36.1%, P < .001), the sutures running sagittally, but articulating indirectly to the maxilla (94.4% vs 64.8%, P < .001), and the sutures running coronally, but articulating indirectly to the maxilla (58.3% vs 33.3%, P < .01). The sutures running sagittally were opened significantly more (94.4%-100.0%) than those running coronally (56.9%-58.3%), no matter if they articulated directly or indirectly with the maxilla.


CONCLUSIONS
Alt-RAMEC opens both the sagittally and coronally running circumaxillary sutures quantitatively more than conventional RME. However, more than 5 weeks of Alt-RAMEC would be needed to increase the opening of the coronally running circumaxillary sutures. (
Wang
Yu-Chi
YC
Department of Orthodontics and Craniofacial Dentistry, Gung Memorial Hospital, Taipei, Taiwan.
Chang
Peter M S
PM
Liou
Eric Jein-Wein
EJ
D000202:Activator Appliances; D000818:Animals; D017849:Animals, Inbred Strains; D002415:Cats; D002508:Cephalometry; D003250:Constriction; D003393:Cranial Sutures / Q000473:pathology*; D005624:Frontal Bone / Q000473:pathology; D008437:Maxilla / Q000473:pathology*; D009296:Nasal Cavity / Q000473:pathology; D009915:Orbit / Q000473:pathology; D016382:Orthodontic Appliance Design; D010155:Palatal Expansion Technique / Q000295:instrumentation; D010159:Palate / Q000473:pathology; D011897:Random Allocation; D013701:Temporal Bone / Q000473:pathology; D015050:Zygoma / Q000473:pathology