Purpose: This retrospective study evaluated the treatment effectiveness and efficiency of the DF2 protocol for correction of class II malocclusions in comparison to conventional protocol using Invisalign®.

Materials and Methods: Clinical and cephalometric data of patients that were treated for class II malocclusion between July 30, 2014 and July 22, 2021 were reviewed and selected. The selected patients were matched for age, sex, and treatment complexity and divided into two groups: Group 1 (G1) —DF2 protocol and Group 2 (G2)—conventional class II Invisalign®. Clinical variables to represent the skeletal and dentoalveolar changes during treatment were assessed using pre-treatment (T1) and post-treatment (T2) digital study models and cephalometric tracings. Statistical analysis was accomplished using Mann-Whitney U and Spearman’s rho tests (α = 0.05). Intra-rater reliability was expressed as intraclass correlation coefficient (ICC).

Results: A total of 22 patients (6 males, 6 females in G1 and 5 males, 5 females in G2) with a mean age of 15.29 (14.27 in G1, 16.52 in G2) years of age were included in this study. Excellent intra-rater reliability was reported (ICC > .95). There were no statistically significant differences in T1 age, discrepancy index (DI), or treatment length between the groups (p > .05). There were no differences in the amount of T1 class II or their changes (molar and canine) following treatment between the groups (p > .05). The amount of T1 overjet (OJ) was statistically more in G1 at T1 leading to a significantly greater reduction in OJ in G1 after treatment (p < .05). All other cephalometric variables at T1 and their changes were comparable between groups (p > .05). No correlation was observed between treatment length and DI, molar and canine corrections (p > .05) except between treatment length versus canine correction in G2 (p < .05).

Conclusion: The results of this study indicate the efficacy and efficiency of both protocols are comparable in class II correction. However, the lack of correlation between treatment time and the amount of class II correction in DF2 group suggests that this protocol may be beneficial when significant class II correction is required.

LLU Discipline

Orthodontics and Dentofacial Orthopedics


Orthodontics and Dentofacial Orthopedics


School of Dentistry

First Advisor

Kitichai Rungcharassaeng

Second Advisor

Joseph M. Caruso

Third Advisor

Andrew A. Ferris

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Malocclusion -- therapy; Orthodontic Appliance Design; Orthodontics, Corrective; Outcome Assessment, Health Care; Retrospective Studies



Page Count

xii, 38 p.

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives