Relapse tendency after orthodontic correction of upper front teeth retained with a bonded retainer.
OBJECTIVE
To investigate the amount and pattern of relapse of maxillary front teeth previously retained with a bonded retainer.


METHODS
The study group consisted of 135 study casts from 45 patients. Recordings from study models before treatment (T1), at debonding (T2), and 1 year after removal of the retainer (T3) were present. All patients had been treated with fixed edgewise appliances. The irregularity index (sum of contact point displacement [CPD]) and rotations of front teeth toward the raphe line were calculated at T1, T2, and T3.


RESULTS
The mean irregularity index at T1 was 10.1 (range 3.0-29.9, SD 5.4). At T2 it was 0.7 (range 0.0-2.1, SD 0.7), and at T3 it was 1.4 (range 0.0-5.1, SD 1.2). Fifty-five teeth in 42 patients were corrected more than 20 degrees between T1 and T2 (mean correction 31.4 degrees range 20.0-61.7), and mean relapse in this group was 7.3 degrees (range 0.0-20.5). Regarding alignment of the maxillary front teeth, the contact relationship between the laterals and centrals seems to be the most critical. A significant positive correlation was found between the amount of correction of incisor rotation and the magnitude of relapse but not between the amount of correction of CPD and the magnitude of relapse. Eighty-four percent of the overcorrected CPDs returned to a desired position.


CONCLUSIONS
Minor or no relapse was noted at the 1-year follow-up.
Naraghi
Sasan
S
The County Orthodontic Clinic in Växjö, Kronoberg, Sweden. sasan@telia.com
Andrén
Anders
A
Kjellberg
Heidrun
H
Mohlin
Bengt Olof
BO
D000293:Adolescent; D000328:Adult; D002508:Cephalometry; D003481:Cuspid / Q000473:pathology; D003724:Dental Arch / Q000473:pathology; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor / Q000473:pathology*; D008310:Malocclusion / Q000473:pathology / Q000628:therapy; D008437:Maxilla; D009967:Orthodontic Appliances; D018704:Orthodontic Retainers; D012008:Recurrence; D012399:Rotation; D012690:Serial Extraction; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000295:instrumentation