Review Finds Frequent Sinus and Nasal Floor Perforations From Orthodontic Mini-Implants

Edited by Dentaltown staff

Radiographic perforation of the maxillary sinus, nasal floor, or incisive canal is a common finding after orthodontic mini-implant placement in the maxilla, though it rarely produced clinical symptoms, according to a systematic review published Sept. 18 in International Orthodontics.

Seven studies covering 702 mini-implants met inclusion criteria out of 98 records screened. Reported maxillary sinus perforation ranged from 8% to 78.3% across those studies, with mean penetration depths between 0.79 mm and 3.23 mm.

Screw length tracked closely with risk. In a cadaver model, sinus perforation rose from none with 6 mm screws to 10% with 8 mm screws and 15% with 10 mm screws. A sinus floor thinner than 6 mm carried an odds ratio of 21.63 for penetration.

Consequences were largely subclinical. Penetration beyond 1 mm raised the rate of Schneiderian membrane thickening from 37.5% to 88.2%, with a mean increase of 0.6 mm, but none of the included studies reported clinical sinusitis.

Anterior palatal placement carried separate risks. Incisive canal perforation affected 25% of subjects and 13.5% of mini-implants, and nasal floor perforation reached 21.2% of subjects and 11.5% of implants, at a mean depth of 1.4 mm. A single oronasal fistula, which followed explantation of an osseointegrated palatal implant, was the only severe complication reported.

Researchers at LMU University Hospital in Munich led the review with colleagues at the University of Bern, the Medical University of Graz, Sapienza University of Rome, and Yale School of Medicine. The protocol was registered with PROSPERO and the review followed PRISMA guidelines, with methodological quality assessed using Joanna Briggs Institute tools.

The authors concluded that risk is shaped by sinus floor thickness, screw length, insertion angle, age, and anterior crowding, and recommended cautious length selection and three-dimensional planning. The wide range in reported perforation rates reflects differences in study design and placement conditions, and the review does not produce a single pooled estimate.

Sources:
International Orthodontics, “Over-insertion of orthodontic mini-implants in the maxilla: A systematic review of maxillary sinus, nasal floor and incisive canal perforations,” published online Sept. 18, 2026: doi.org/10.1016/j.ortho.2026.101247
PubMed record, PMID 42759072: pubmed.ncbi.nlm.nih.gov/42759072