Root resorption during orthodontic treatment with Invisalign®: a radiometric study

Area of Science:

• Dentistry
• Orthodontics
• Periodontology

Background:

• Root resorption (RR) is the permanent loss of tooth structure from the root apex.
• Orthodontic treatment is associated with an increased risk of apical root shortening, particularly in maxillary and mandibular incisors.
• The incidence and severity of RR in adult patients undergoing clear aligner therapy require further investigation.

Purpose of the Study:

• To investigate the incidence and severity of root resorption (RR) in adult patients treated with clear aligners (Invisalign®).

Main Methods:

• The study included 71 adult patients with Class I malocclusion treated with Invisalign® aligners.
• Panoramic radiographs were used to measure root and crown lengths of 1083 teeth (incisors, canines, first premolars, first molars) at the beginning (T0) and end (T1) of treatment.
• Relative changes in the root-crown ratio (rRCR) were calculated to assess root length reduction.

Main Results:

• All patients exhibited some degree of root length reduction, averaging 6.38 ± 2.28 affected teeth per patient.
• Over 81% of the measured teeth showed a reduction in pre-treatment root length.
• A reduction of >0% to 10% occurred in 25.94% of teeth, >10% to 20% in 12.18%, and >20% in 3.69%.

Conclusions:

• Orthodontic treatment using Invisalign® clear aligners can lead to root resorption (RR).
• The incidence of RR observed in this study is similar to that reported for traditional orthodontic light forces.
• The average percentage of RR was less than 10% of the original root length.