According to classic Hirschfeld studies, the first teeth to be lost are the first and second maxillary molars. After the teeth are extracted and the alveolar process is developed, the maxillary sinus is reabsorbed and pneumatized with a decrease in bone availability in the posterior sector of the maxilla. This process often creates the need to perform regeneration techniques for the placement of implants in this area due to the low availability of bone. The most frequently used and documented technique for the elevation of the sinus maxillary floor is elevation by the side window, as proposed by Tatum. In 1994, Summers proposed a technique that allowed the elevation of the sinus floor from a crestal access using an instrument called an osteotome, as well as the placement of the implant in the same surgical act. The aimed of the study was to evaluate the survival of 32 implants placed in posterior maxilla with bone availability less than 5 mm performing a sinus lift augmentation technique with osteotome without biomaterials. The results of this study show a survival rate of 100% for 32 implants placed in situations with an initial bone availability of 2 to 5 mm without the use of graft material. The infra-drilling technique used offers an increase in the primary stability of implants that allows adequate osteointegration Implants placed were charged at 12 weeks. In all cases, spontaneous bone formation was observed, even in cases where a positive Valsalva maneuver was observed. This proposed technique reduces treatment time and the need for more invasive maxillary sinus augmentation techniques.

Purpose: The aim of this retrospective study was to compare the influence of removing or not removing a prosthesis after regenerative surgery on peri-implant defects. Methods: Two different groups were compared (Group 1: removing the prosthesis; Group 2: maintaining the prosthesis), analyzing radiographic bone filling (n = 32 implants) after regenerative treatment in periapical radiographs. The peri-implant defects were measured before and after regenerative treatment using Bio-Oss® (Geistlich Pharma, Wohhusen, Switzerland) and a reabsorbable collagen membrane (Jason®, Botis, Berlin, Germany), the healing period was two years after peri-implant regenerative surgery. Statistical analysis was performed, and a Chi square test was carried out. To determine the groups that made the difference, corrected standardized Haberman residuals were used, and previously a normality test had been applied; therefore, an ANOVA or Mann–Whitney U test was used for the crossover with the non-normal variables in Group 1 and Group 2. Results: The results obtained suggest that a regenerative procedure with xenograft, resorbable membrane, and detoxifying the implant surface with hydrogen peroxide form a reliable technique to achieve medium-term results, obtaining an average bone gain at a radiographic level of 2.84 mm (±1.78 mm) in patients whose prosthesis was not removed after peri-implant bone regenerative therapy and 2.18 mm (±1.41 mm) in patients whose prosthesis was removed during the healing period. Conclusions: There are no statistically significant differences in the response to treatment when removing or keeping the prosthesis after regenerative surgery in peri-implant defects.