Risk Assessment of Lingual Plate Perforation in Posterior Mandibular Region: a Virtual Implant Placement Study Using Cone-beam Computed Tomography

Background: Lingual plate perforation at the time of implant placement in posterior mandible is a potential surgical complication, and presence of a lingual concavity is considered a risk factor. Little is known about the spatial relationship between implant and lingual plate. The role of lingual concavity in the risk of lingual perforation has not yet been fully studied. This computer-simulated study investigates the incidence of lingual plate perforation in edentulous mandibular first molar region and the risk of perforation in the area of lingual concavity.

Methods: One hundred and three qualified cone-beam computed tomography scans were selected from the database. Implants of various dimensions were virtually placed into the area using computer software. The distance between implant tip and lingual plate was measured using a digital caliper. Incidence of lingual plate perforation and proximity of the implant tip to lingual plate were measured for three types of cross-sectional mandibular morphology.

Results: One hundred and three cone-beam computed tomography scans with 118 sites were available for analysis. The intraexaminer and interexaminer agreements were 0.93 and 0.89, respectively. The predicted incidence of lingual plate perforation was 1.1% to 1.2%. Most implants, which were within 1 mm from lingual plate, occurred in sites with lingual concavity (type-U ridge).

Conclusions: This study demonstrates a novel experimental design by which the spatial relation between implant and lingual plate in mandibular first molar region is investigated. Incidence of lingual plate perforation during implant placement is predicted to be 1.1% to 1.2% and it will most likely happen in type-U ridge.