Objectives

To evaluate leveling of the Curve of Wilson (COW) by two different treatment appliances (clear aligners [CA] and continuous archwire fixed appliances [FA]) in a permanent dentition sample of patients.

Materials and Methods

Digital casts of 40 patients (CA group = 20 patients; FA group = 20 patients) were collected. Angular values for COW, right and left vertical height difference of lower first molars, and linear distance between lower teeth and the WALA ridge were analyzed for pre- (T1), posttreatment (T2) and on final virtual (ClinCheck) models (T2-CC) of the CA group. An unpaired t-test was used to evaluate significant intergroup differences (P < .05), while a paired t-test was used for posttreatment CA intragroup comparison.

Results

FA group showed better control of second molar crown positions compared to CA group (47-WALA = −0.2 ± 0.1 mm, 37-WALA = −0.6 ± 0.3 mm). No significant difference was detected for linear distance of lower first molars and the WALA ridge or for vertical height difference. CA group showed a greater reduction of distance between lower premolars and the WALA ridge (mean difference: –0.5 mm for both 45-WALA and 35-WALA; mean difference: −0.5 mm for 44-WALA, −0.6 mm for 34-WALA). Predictability for the CA group was high for every measurement (87% Right COW, 89% Left COW, 88% 46 Vertical Diff, 87% 36 Vertical Diff).

Conclusions

Clear aligner and continuous archwire mechanics were effective in leveling COW. FA was more effective in changing crown position of lower second molars with respect to the WALA ridge, while CA provided a greater distance reduction between lower premolars and WALA ridges compared to FA.

This content is only available as a PDF.

Author notes

a

PhD Research Assistant, Department of Health Sciences, UniCamillus-Saint Camillus International Medical University, Rome, Italy.

b

Postgraduate Student, Department of System Medicine, University of Rome Tor Vergata, Rome, Italy.

c

Professor, Department of Health Sciences, UniCamillus-Saint Camillus International Medical University, Rome, Italy.

d

PhD Research Assistant, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.