Extra-Short 4-mm Implants Splinted to 10-mm Implants in the Posterior Maxilla: 3-year Results

To evaluate the 3-year success and survival rates of fixed prostheses supported by 4-mm extra-short implants splinted to 10-mm implants in patients with shortened maxillary arches and low maxillary sinus floors.A total of 11 patients with reduced alveolar bone heights due to low maxillary sinus floors received two or three titanium-zirconium tissue-level implants: one or two extra-short (4 mm) implants, and one implant 10 mm in length. After 6 months, prosthetic rehabilitation with splinted crowns connecting the 4- and 10-mm implants was performed. Follow-up visits and maintenance protocols were implemented every 4 to 6 months.The 11 patients were treated with 11 10-mm implants and 17 4-mm implants. One extra-short implant failed and was removed before loading, and its planned design was modified from three splinted crowns to a bridge between the 10- and 4-mm implants. After 36 months, all (11/11) prosthetic rehabilitations connecting the 10-mm (11/11) and 4-mm (16/16) implants were functional. At the 10-mm implant sites, the median (interquartile range [IQR]) probing depth and marginal bone loss measured 2.9 mm (2.3 to 3.2) and 1.3 mm (1.0 to 1.5), respectively. At the 4-mm implant sites, the median (IQR) probing depth and marginal bone loss measured 2.9 mm (2.4 to 3.1) and 0.3 mm (0.1 to 0.5), respectively.Prosthetic rehabilitation with splinted crowns connecting 4-mm and 10-mm implants showed promising outcomes in shortened maxillary dental arches after 3 years. Additional studies are needed to further validate these findings.