Evaluation of the predicted vs. achieved occlusal outcomes with the Invisalign® appliance: A retrospective investigation of adult patients

Emma Bowman; Patrick Bowman; Tony Weir; Craig W Dreyer; Maurice J Meade

doi:10.1016/j.ortho.2023.100746

Evaluation of the predicted vs. achieved occlusal outcomes with the Invisalign® appliance: A retrospective investigation of adult patients

Int Orthod. 2023 Jun;21(2):100746. doi: 10.1016/j.ortho.2023.100746. Epub 2023 Mar 1.

Authors

Emma Bowman¹, Patrick Bowman², Tony Weir¹, Craig W Dreyer¹, Maurice J Meade³

Affiliations

¹ Orthodontic Unit, Adelaide Dental School, The University of Adelaide, Adelaide, Australia.
² Private periodontal practice, Bondi Junction New South Wales, Sydney, Australia.
³ Orthodontic Unit, Adelaide Dental School, The University of Adelaide, Adelaide, Australia. Electronic address: maurice.meade@adelaide.edu.au.

PMID: 36868001
DOI: 10.1016/j.ortho.2023.100746

Abstract

Introduction: The aim of this study was to investigate the relationship between occlusal contacts, overbite, transverse expansion, and the buccolingual inclination of the teeth with reference to the predicted treatment outcomes and achieved outcomes related to the use of the Invisalign® appliance in mild-to-moderate Class I malocclusions.

Material and methods: The occlusal contacts, overbite, the buccolingual inclination and transverse expansion of the maxillary arch of adult patients satisfying inclusion and exclusion criteria were measured at the initial (pre-treatment), predicted, and achieved treatment stages using metrology software. Pearson correlation coefficients and regression equations were calculated to determine the association between the initial, predicted and achieved changes in occlusal contact against the other variables.

Results: Thirty-three patients, who commenced treatment between 2013 and 2018 and satisfied inclusion/exclusion criteria were evaluated. An overall loss of posterior contact was recorded and highlighted by a significantly greater loss of contact from the maxillary buccal occlusal surfaces compared to the palatal occlusal surfaces. The mean [SD] achieved overbite outcome (2.94mm [1.17]) was greater than the predicted (1.74mm [0.87), P<0.001). The buccolingual inclination was significantly increased for the lateral incisors and first and second molars despite a predicted decrease (P≤0.007). Achieved transverse expansion showed significant variation from the predicted. The loss of posterior occlusal contact was correlated with the buccolingual inclination (r=0.70) and transverse expansion (r=0.74) of the posterior teeth.

Conclusions: In mild-to-moderate Class I malocclusions, treatment using the Invisalign® appliance resulted in an overall loss of posterior contact. The loss of occlusal contact was correlated with deficiencies in achieved buccolingual inclination and transverse expansion of the posterior teeth. Planned bodily expansion was ineffective as most expansion occurred due to unplanned buccal tipping.

Keywords: Clear aligner therapy; Invisalign®; Occlusal outcomes; Orthodontic treatment outcomes.

MeSH terms

Adult
Humans
Malocclusion* / therapy
Malocclusion, Angle Class I* / therapy
Malocclusion, Angle Class II*
Orthodontic Appliances, Removable*
Overbite* / therapy
Retrospective Studies
Treatment Outcome