Hypersensitivity in Orthodontics: A Systematic Review of Oral and Extra-Oral Reactions.

Background/

Objectives

This systematic review analyzed the epidemiologic and macro/microscopic features of manifestations of hypersensitivity reactions with oral and extra-oral involvement in orthodontic patients with fixed (FAs) or removable (RAs) appliances or clear aligners (CAs), and evaluated them based on patient and treatment characteristics to provide clinical recommendations.

Methods

The study protocol followed the PRISMA guidelines and was registered on PROSPERO (CRD42024517942).

Results

Thirty-one studies were qualitatively assessed and synthetized, involving 858 subjects (114 males and 714 females, 9-49 years old), of whom there were 86 with a history of allergy, and 743 wearing recorded appliances (FAs = 656, FAs and RAs = 81, intra- and extra-oral RAs = 3, CAs = 3), with a mean treatment duration of 21.5 months (6 weeks-40 months). Among 75 reports, 29 (38.67%), describing burning, gingival hyperplasia, erythema, and vesicles, had oral involvement, while 46 (61.33%) had skin, eye, and systemic involvement, with erythema, papules, conjunctival hyperemia, and vertigo. Positive allergy tests concomitant with the manifestations identified nickel 451 times, cobalt 6 times, titanium 5 times, and chromium 4 times. Management included antihistamines or corticosteroids and removing the offending materials, with treatment discontinuation/appliance substitution.

Conclusions

Pre-treatment evaluations, including patient histories and allergy testing, are essential to identify potential allergens and select hypoallergenic materials like titanium or ceramic brackets; regular monitoring and early intervention during treatment are crucial to prevent severe outcomes.