Prevalence of pulpal necrosis in healthy teeth during Invisalign treatment

Clear aligner therapy is widely used in dental and orthodontic practice, but pulpal outcomes in trauma-free teeth remain poorly defined.

This retrospective study evaluated the prevalence of pulpal necrosis in trauma-free teeth during orthodontic treatment. A stratified sample of 1,000 patients was reviewed: 250 adolescents treated with Invisalign Teen (Align Technology, Inc) and 250 adults treated with Invisalign Full (Align Technology, Inc) plus a comparison group of 250 adolescents and 250 adults treated with labial fixed appliances. Digital clinical records were examined to identify diagnoses of pulpal necrosis made during active treatment. Patients with a history of dental trauma were excluded. Primary independent variables included treatment modality (Invisalign vs fixed appliances) and age group (< 20 years vs ≥ 20 years). An exploratory multivariable logistic regression analysis adjusted for baseline covariates was performed.

Pulpal necrosis was uncommon in both treatment groups but was observed more often among patients treated with Invisalign. In the Invisalign cohort, pulpal necrosis occurred in 3.4% of adolescents and 1.6% of adults. All Invisalign-associated cases were diagnosed within the first 12 months of treatment. The maxillary central incisor was the most commonly affected tooth (91.7%).

Pulpal necrosis was an uncommon finding in trauma-free teeth during orthodontic treatment. Although the observed rate was higher among patients treated with Invisalign, the small number of events and potential confounding factors limit interpretation.

Clinicians should assess occlusal interferences throughout active clear aligner therapy. Combining maxillary incisor retroclination with anterior bite turbos and lower incisor intrusion may help reduce excessive pulpal loading.