Long-Term Comparative Outcomes of Short Implants Versus Maxillary Sinus Elevation in Posterior Maxilla Rehabilitation

Background: Vertical atrophy of the maxilla has traditionally been treated with sinus lift procedures and implant placement, performed in one or two surgical stages. Subsequently, the transcrestal sinus lift technique was introduced, offering distinct advantages in terms of indications and reduced morbidity. Most recently, short implants have emerged as a valid alternative to these procedures, even in cases of severe horizontal resorption, allowing for direct placement in many cases. This study was designed to assess the clinical outcomes of short implant placement in alveolar ridges with severe bone atrophy, compared with conventional-length implants placed in areas undergoing conventional sinus elevation. Methods: A retrospective split-mouth study was conducted to compare conventional sinus elevation with standard-length implants versus short implants for addressing vertical bone atrophy in the posterior maxilla. The primary variable was the variation in the marginal bone level. The secondary variables were implant survival and complications. The evaluation of the statistical significance of the difference in categorical variables was accomplished by Chi-squared test or Fisher's exact test. The comparison between the study groups in continuous variables was performed using Wilcoxon test. The statistical significance was set at p-value < 0.05. Results: The study sample consisted of 24 patients and a total of 73 dental implants. The lateral sinus elevation group (LSEG) included 39 implants, while the short implants group (SIG) included 32 implants. All prostheses were screw-retained. Changes in marginal bone levels indicated a marginal bone loss of less than 0.5 mm in both groups, with no statistically significant difference. In the LSEG, two cases of mucositis were identified, attributed to improper use of an interdental brush. Additionally, two cases of prosthetic screw fracture were reported in the LSEG as technical complications. Conclusions: Long-term outcome data have provided evidence that the use of short implants is comparable to a state-of-the-art procedure (sinus grafting and placement of implants) regarding implant survival, marginal bone remodeling, and complication rates.