Geometric morphometric evaluations of a randomized prospective split-mouth study on modes of ligation and reverse-curve mechanics.
OBJECTIVE
To evaluate tooth position after six and 9 months of orthodontics with conventional brackets on one side of the dentition and ligature-less brackets on the other.


METHODS
Orthodontic Division, Vienna Medical University. Twenty patients aged 22.5 ± 5.7 years, symmetrical malocclusion and arch form, no premolar extraction.


METHODS
Prospective split-mouth study, 0.022-inch SmartClip self-ligating brackets assigned randomly to the left or right dentition, conventional 0.018-inch brackets on the other side. 52 dental landmarks, digitized on plaster casts, represented dental arches at baseline (t0), 6 months and 9 months (t1, t2). During t0-t1, we used 0.016 and 0.014 x 0.025 inch superelastic wires, during t1-t2 connected reverse-curve hemiarch wires: 0.017 x 0.025 inch ß-titanium on the ligature-less side, and 0.016 x 0.022 inch Elgiloy multiloop wires on conventional brackets. Morphometric analyses were used to assess differences in dental arch shapes.


RESULTS
Neither initial alignment nor the reverse-curve phase showed statistically significant differences between ligature-less and conventional brackets in moving teeth.


CONCLUSIONS
Morphometric shape analyses corroborated current evidence that self-ligating brackets were no more effective than conventional brackets with steel ligatures after 6-month initial alignment. From months 6-9 treatment with ß-titanium reverse-curve wires on 0.022-inch ligature-less brackets resulted in similar tooth positions as accomplished by Elgiloy multiloop wires on 0.018-inch steel-ligature-tied brackets.
Orthodontic Division, Dental Clinic, Medical University of Vienna, Vienna, Austria.
A G
AG
Celar
K
K
Onodera
M H
MH
Bertl
E
E
Astl
H-P
HP
Bantleon
S
S
Sato
P
P
Mitteroecker
D000293:Adolescent; D000328:Adult; D059925:Anatomic Landmarks / Q000473:pathology; D002508:Cephalometry / Q000379:methods*; D002648:Child; D003722:Dental Alloys / Q000737:chemistry; D003724:Dental Arch / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008311:Malocclusion, Angle Class I / Q000628:therapy; D008312:Malocclusion, Angle Class II / Q000628:therapy; D008313:Malocclusion, Angle Class III / Q000628:therapy; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D011446:Prospective Studies; D013232:Steel / Q000737:chemistry; D014025:Titanium / Q000737:chemistry; D014070:Tooth / Q000473:pathology*; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
D003722:Dental Alloys; C023988:beta titanium; D013232:Steel; D014025:Titanium
geometric morphometrics; principal component analysis; reverse curve; self-ligation; split mouth