Sinus presurgical evaluation: a literature review and a new classification proposal.

INTRODUCTION: Presurgical evaluation with cone beam computed tomography (CBCT) or computed tomography (CT) has become an essential tool for diagnosis and surgical planning, including maxillary sinus floor elevation. Before performing a sinus lift, the clinician's attention should not be only directed to the patency of the ostium through CBCT or CT, because many anatomical features could influence the surgical approach of sinus floor elevation. The goal of this article was to facilitate the communication between clinicians regarding the type of maxillary sinus, encourage in-depth analysis prior to surgery and reduce the risk of complications due to possible underestimation of important parameters. EVIDENCE ACQUISITION: An electronic search was conducted in Pubmed, Embase, Medline and Scopus, matching the following keywords: "sinus lift", "CBCT", "CT", "presurgical" and "evaluation". Clinical Oral Implant Research, Implant Dentistry, International Journal of Periodontics and Restorative Dentistry and Journal of Oral Implantology were hand-searched. The bibliographies of review articles were checked and personal references were also searched. EVIDENCE SYNTHESIS: Eleven parameters, that clinicians must check every time through CBCT or CT, were evaluated from different studies. At the end of the literature review for every single feature, the Authors established a favorable, a normal and an unfavorable situation, in order to provide a new classification. CONCLUSIONS: The grade of the described classification may be useful for clinicians to understand what probably the risk level of the sinus lift surgery could be and it may encourage the surgeon to have a careful pre-operative evaluation through CBCT or CT.