Shih-Cheng Wen Yen-Hua Lin Yeuh-Chao Yang Hom-Lay Wang The influence of sinus membrane thickness upon membrane perforation during transcrestal sinus lift procedure Authors’ affiliations: Shih-Cheng Wen, Private Practice, Taipei County, Taiwan, Yen-Hua Lin, Yeuh-Chao Yang, Department of Dentistry, Cathay General Hospital, Taipei City, Taiwan Hom-Lay Wang, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA Corresponding author: Hom-Lay Wang 1011 North University Avenue, Ann Arbor, MI 48109-1078, USA Tel.: +734 763 3325 Fax: +734 936 0374 e-mail: homlay@umich.edu Key words: cone-beam computed tomography, membrane perforation, membrane thickness, sinus lift, transcrestal Abstract Objectives: Schneiderian membrane perforation is one of the main complications during sinus augmentation. The reasons may be associated with surgical technique, septum, inadequate ridge height, and membrane thickness. However, reports that used cone-beam computed tomography (CBCT) to quantify the thickness of sinus membrane were limited. The aims of this retrospective study were: to study the correlation between membrane thickness and perforation rate during transcrestal sinus lift and to propose a classification system of sinus membrane thickness based upon CBCT data. Material and methods: One hundred and twenty-two subjects who received dental implant restorations over posterior maxilla with a total of 185 transcrestal sinus lift procedures between years 2010 to 2013 were selected consequently. Each patient selected had to have taken CBCT in the initial examination and immediately after surgery. The membrane thickness, perforation rate, residual bone height, and elevated bone height were recorded and processed for statistical analysis. Results: The mean thickness of the Schneiderian membrane was 1.78 Æ 1.99 mm. There was a significant correlation between membrane thickness and perforation rate (P < 0.05), and the perforation rate was higher in thicker (≥3 mm) and thinner membrane (≤0.5 mm). Among the thickness group, Class B (between ≥1 and <2 mm) had the lowest perforation rate. No significant difference was between the perforation and the membrane morphology. A negative relationship between residual bone height and membrane thickness was found. Trend showed that in the thicker and the thinner residual bone height, the higher the perforation rate would be. Conclusions: There was a significant correlation between membrane thickness and perforation rate. The perforation rate was lowest when the thickness was 1.5–2 mm. Dental implant has become a popular treat- ment modality for replacing missing teeth. However, patients with edentulous ridge over posterior maxilla often suffered from insuffi- cient bone height for dental implantation. Besides alveolar ridge resorption, maxillary sinus pneumatization exacerbated the situa- tion. Sinus floor elevation technique had been proposed to overcome the insufficient bone height problem. It can be accomplished via either a lateral approach (Boyne & James 1980) or a crestal approach (Summers 1994), depending on the residual bone height and the possibility of achieving adequate primary implant stability (Wang & Katranji 2008). High survival rate of dental implants placed into the grafted sinus had been reported (Wallace & Froum 2003; Pjetursson et al. 2008; Yamamichi et al. 2008; Del Fabbro et al. 2012) and compared favorably to those placed in the non-grafted posterior maxilla (Wallace & Froum 2003). Nonethe- less, the complications do occur. The most common complication during sinus augmen- tation was membrane perforation (Vlassis & Fugazzotto 1999; Schwartz-Arad et al. 2004; Nkenke & Stelzle 2009). The incidence of perforation ranged from 20% to 44% in lat- eral approach and 0% to 25% in crestal approach (Katranji et al. 2008). A small tear in the membrane resulted in direct commu- nication between the graft material and the contaminated sinus cavity. This can cause infection and chronic sinusitis, which could lead to loss of graft volume or implant failure (Katranji et al. 2008). The size of perforation was also suggested to be related to the prog- nosis of the implant (Hernandez-Alfaro et al. Date: Accepted 3 May To cite this article: Wen S-C, Lin Y-H, Yang Y-C, Wang H-L. The influence of sinus membrane thickness upon membrane perforation during transcrestal sinus lift procedure. Clin. Oral Impl. Res. 26, 2015, 1158–1164. doi: 10.1111/clr.12429 1158 © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd