using cone beam computed tomography to detect the relationship between the periodontal bone loss and mucosal thickening of the maxillary sinus

background: maxillary sinuses are covered by a 1 mm thick mucous membrane that when this membrane becomes infl amed, the thickness may increase 10-15 times. the common causes of odontogenic sinusitis are dental abscesses and periodontal disease. computed tomography (ct) is considered the gold standard for sinus diagnosis. recently, cone beam computed tomography (cbct) has been introduced for dental and maxillofacial imaging, which has several advantages over traditional ct, including lower radiation dose and chairside process. this study aims to fi nd the association between mucosal thickening (mt) of the sinus and periodontal bone loss (pbl) and pulpoperiapical condition. materials and methods: a total of 180 cbct images were reviewed. pbl was assessed in six points under each sinus at the mesial and distal sides of the upper second premolar and fi rst and second molars by measuring the distance from the alveolar crest to the point 2 mm under the cemento-enamel junction (cej). the mt was assessed at six points in the fl oor of the sinus precisely over the mentioned points. to assess the possible role of pulpoperiapical condition on the sinus mt, the existing teeth were classifi ed into fi ve groups due to the probable effect of each condition on the pulp and peri-apex. the statistical association between mt of sinus and pbl and pulpoperiapical condition was assessed using spss software (spss inc., version 16.0, chicago, il, usa) and bivariate correlation and binary linear regression statistical tests (p < 0.05). results: mt was observed in 39.4% of patients (mean = 4.68 ± 5.25 mm). pbl was seen in 33% of the patients (mean = 1.87 ± 1.63 mm). linear regression test showed that there is an association between both pbl and pulpoperiapical condition and mt, but the effect of pbl was about 4 times stronger. conclusion: this study showed that mt of the maxillary sinus was common among patients with pbl and mt of the maxillary sinus was signifi cantly associated with pbl. key words: maxillary sinus, mucosal thickening, periodontal bone loss