Introduction: In 2006 an ultrasound-surgery-based method to hydrodynamically detach the sinus-membrane utilizing the ultrasonic cavitation effect-the tHUCSL-was developed and a surgical protocol established. The aim of the study was to determine the indication-range and success-rate of this novelty procedure. Materials & Methods: Between 2007 and 2009, 404 patients were treated by 6 oral surgeons of different experience-levels with the tHUCSL in 446 sinussites. 637 implants were inserted and then prosthodontically treated and observed and documented until December 2011. The subantral space was augmented via the 3 mm transcrestal approach with an augmentation volume of 1.9 ccm (+/− 0.988 ccm) and an augmentation height of 10.7 mm (+/− 2.85 mm). Results: Within the survey-period 15 (2.35%) of the 637 inserted implants were lost, mostly before implant loading due to postsurgical infection and nonosseointegration in the augmentation site. 1 implant was lost after implant loading and prosthetic treatment within 1 year after loading. The overall success rate with functional implants in site is 97.65% evenly distributed among the participating surgeons. 86% of the patients were observed with no postsurgical swelling and 87% no postsurgical pain. Discussion: The results suggest the tHUCSL to be a safe minimal-invasive alternative to traditional lateral approach and transcrestal osteotome sinuslift-procedures applicable to all anatomical situations.

Introduction: The current discussion about the use of short implants to avoid bone-augmentation ("sinus lift") in the lateral maxilla remains a controversial topic and is increasingly at odds with the reality of evolutionary biology. Aim of the study was to determine the percentage of cases from a large routine patient-sample in which short implants might be suitable to avoid sinus lift procedures. Materials and Methods: From January 2012 to June 2015, all patients in three general dental practices in Austria with at least one subantral edentulous area were subjected to routine panoramic X-ray screening. The subantral alveolar ridge heights and the mesial extension of the maxillary sinus towards the canine fossa were measured. Statistics were performed by Excel data analysis (mean value, standard deviation). Results: 2837 patients were screened with 2837 panoramic radiographs presenting 3528 edentulous subantral regions and the subantral bone heights of 5674 maxillary sinuses were surveyed. 57.43% revealed subantral alveolar ridge heights of 4 mm or less; 24.43% of all measure-points indicated a maximum alveolar ridge height of 6 mm. In 39.32% of cases, the pneumatisation of the maxillary sinuses with a subantral residual ridge height of 6 mm or less extended as far as the anatomical position of the second premolars, in 20.51% as far as the position of the first premolar and in 10.84% as far as the canine fossa. Discussion: The sinus lift procedure will continue to be one of the basic standard surgical procedures carried out by practice-based dental surgeons who perform implant surgery since in at least two thirds of the cases short implants with lengths of less than 6 mm cannot be applied. Preference should be given to sinus liftprocedures, which can be learned safely with a minimum of time-effort, least risk of failure and lowest possible level of patient morbidity. Transcrestal hy- 2 drodynamic ultrasonic sinus lift-procedures with piezotomes seem to fulfill these basic demands.