Aim: The aim of this study is to evaluate the clinical and radiographic outcomes of PEEK/ PSI containing autogenous bone graft after enucleation of unilateral maxillary lesion encroaching maxillary sinus. Subjects and Methods: This study was conducted on ten patients (4 males and 6 females) with unilateral maxillary cysts encroaching the maxillary sinus. The age of the patients ranged from 15 to 59 with a mean of 33.1 years. All cases underwent surgical enucleation followed by immediate grafting with autogenous bone/xenograft mix in a PEEK /PSI to reconstruct the alveolar process and the maxillary sinus floor. Results: the results of this study demonstrated that pain intensity score according to the Visual Analogue Scale for the ten patients revealed: a minimum of 6 and a maximum of 10 with a mean of 7.2 preoperatively and a minimum of 0 and a maximum of 4 with a mean value of 1.8 one week postoperatively. According to radiographic results, Case number 5 was excluded from the statistical analysis of the radiographic results, as the PSI and the graft were removed 1 month postoperatively. Immediate postoperative bone density for 9 patients revealed: a minimum of 203.81 HU and a maximum of 413.79 HU with a mean of 318.79 HU. 4 months postoperative bone density for 9 patients revealed: a minimum of 274.75 HU and a maximum of 487.14 HU with a mean of 369.43 HU. Conclusion:The statistical analysis of the bone density immediately and 4 months postoperatively is considered to be very statistically significant.