Effect of Clear Aligner Attachment Size on Extrusion of Maxillary Lateral Incisors

Effect of Clear Aligner Attachment Size on Extrusion of Maxillary Lateral Incisors

Orthodontic treatment has been revolutionized by clear aligner therapy, offering patients a more esthetic and comfortable alternative to traditional braces. In 1999, Align Technology introduced Invisalign. As Invisalign has increased in popularity and demand over the past two decades, clinical trials have shed light on the efficacy of Invisalign treatment. there have been changes in the Invisalign protocol such as introduction of SmartForce features in 2008, such as optimized attachments as well as the implementation of SmartTrack aligner material in 2011. Compared to conventional fixed orthodontic appliances, Invisalign cannot be adjusted on a visit-to visit basis. If ideal tooth movement has not been achieved after completion of the first sequence of aligners, additional trays, known as refinement trays, are required.

There are various expert theories regarding the most effective methods of extrusion and multiple studies performed in vitro to evaluate the efficacy of different attachment types on the extrusion of lateral incisors, however only one in vivo clinical trial exists. There is a need for more randomized clinical trials that evaluate the effectiveness of different attachment designs for achieving optimal extrusion of lateral incisors. By determining the most effective attachment size for maxillary lateral incisor extrusion, this study can help improve treatment outcomes for orthodontic treatment with clear aligners and serve as a guide to assist clinicians in selecting the most effective attachment design.

Inclusion Criteria:

• Patients treated with either Comprehensive Invisalign or Invisalign Teen treatment
• The maxillary arch has less than 6 mm of crowding or spacing
• Maxillary lateral incisors have a minimum of 0.3 mm of extrusion prescribed in the Tooth Movement Table on the Invisalign ClinCheck for the first set of aligners
• Maxillary lateral incisors within a normal range of bucco-lingual inclination
• Patients 12 years of age or older and either the patient or legal guardian are able to give consent
• Patients confirm good compliance throughout the study period

Exclusion Criteria:

• Patients do not complete all aligners in the first phase as prescribed
• Poor compliance recorded for aligner wear
• Restorations placed or oral surgery completed prior to final scan
• Midcourse intervention to improve tracking such as a bootstrap
• Maxillary lateral incisors not tracking and noted by minimum of 1 mm of aligner material incisally displaced when aligner fully seated
• Treatment plans include surgery or extractions
• Maxillary lateral incisors with pathology and restorations
• Missing teeth other than third molars
• Patients with anterior crossbite