We read with great interest the article by Cerruto et al in the March 2018 issue. The article presents a case of lingual osteonecrosis as a virtually unknown complication associated with the commonly benign use of impression trays in the oral cavity. One similar report was published previously in a journal devoted to oral and maxillofacial surgery. That case showed similar findings and outcome as reported by Cerruto et al.

Osteonecrosis of the jaw may emerge as a response to direct mucosal trauma, not only in the medial aspect of the mandible, but at all locations where the osseous structures are covered by thin mucosa. Most certainly, the initial wound created by the trauma is smaller than the area of osteonecrosis seen by the health care provider at a later stage. Deviations in anatomy, such as a prominent lingual shelf or a prominent mandibular torus, are more important than the amount of force applied to the tray used for the impression. We arrived at this conclusion since the amount of pressure usually applied for an impression is more than enough to cause a mucosal injury if the tray is in direct contact with the thin mucosa. Hence, in the case presented by the authors, the “robust physique” and the excessive pressure exerted by the assistant are of minimal importance, whereas the prominant lingual shelf on the right side (Fig 1) is likely to be a more relevant risk factor.