Cone beam computed tomography analysis of dentoalveolar changes immediately after maxillary expansion.
OBJECTIVE
Rapid maxillary expansion (RME) splits the midpalatal suture to correct maxillary transverse discrepancies and increase the arch perimeter. The goal of this paper is to evaluate the immediate effects of RME with Hyrax appliances on the dentoalveolar complex using cone beam computed tomography (CBCT).


METHODS
Twenty-eight patients (19 females and 9 males) requiring maxillary expansion therapy were included (mean age, 14.1 years; range, 13 to 20 years). CBCT images were taken at T1 (before maxillary expansion) and T2 (immediately after expansion) as part of clinical records. Maxillary arch width, posterior segment angulation, and buccal bone thickness at the level of the first premolar and first molar were evaluated. Paired t tests determined statistical significance (P < .05).


RESULTS
The mean ± SD amount of expansion achieved was 4.7788 ± 2.8474 mm for the maxillary premolars and 4.6943 ± 3.2198 mm for the molars. Significant tipping of the palatal roots of the maxillary right and left premolars as well as that for the maxillary left molar was observed. When present, the thickness of the buccal plate decreased on all observed roots.


CONCLUSIONS
There is a significant increase in interpremolar and intermolar distance with RME. The increase in root angulation suggests that the movement is more tipping than translation. The thickness of the buccal plate decreases immediately after RME. Therefore, the level of inflammation should be closely monitored to avoid periodontal destruction. There is a need to define standardized reference planes and comparable methodology to achieve compatible results among studies.
Department of Orthodontics, University of Texas Health Science Center at Houston, TX, USA.
Carin Elizabeth
CE
Domann
Chung How
CH
Kau
Jeryl D
JD
English
James J
JJ
Xia
Nada M
NM
Souccar
Robert P
RP
Lee
D000293:Adolescent; D000539:Alveolar Process / Q000000981:diagnostic imaging*; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation; D003724:Dental Arch / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla; D010155:Palatal Expansion Technique; D014092:Tooth Root / Q000000981:diagnostic imaging; D016896:Treatment Outcome; D055815:Young Adult