The Use of 4-mm Implants Splinted to 10-mm Implants for Replacement of Multiple Missing Teeth in the Posterior Maxilla Region with Expanded Maxillary Sinus. An Observational Cases Series: Patient Characteristics and Preliminary Results.

This study aimed to rehabilitate shortened maxillary dental arch with splinted crowns by connecting ultra-short implants with longer ones. In the posterior maxilla of 11 patients, one 10-mm (n = 11) and one or two ultra-short 4-mm (n = 17) dental implants were inserted. The insertion torque was lower than 20 Ncm in 55% of the 10-mm implants and in 94% of the 4-mm implants (P > .05). Median (range) implant stability quotients at the time of insertion and after 6 months were 61 (14 to 72) and 68 (51 to 79), respectively, for 4-mm implants, and 66 (52 to 78) and 78 (60 to 83), respectively, for 10-mm implants (P < .05). One 4-mm implant failed to integrate. All patients were restored with splinted metal-ceramic crowns connecting 4- and 10-mm implants. Median (range) clinical crown/implant ratios of 4-mm and 10-mm implants were 2.79 (1 to 3.66) and 1.06 (0.85 to 1.46), respectively (P < .05). Six months after prosthetic rehabilitation, the median (range) crestal bone loss was 0.3 mm (-0.7 to 1.7 mm) for 4-mm implants and was 0.5 mm (-0.8 to 3.5 mm) for 10-mm implants (P > .05). Splinted crowns combining 4- and 10-mm implants may contribute to a better force distribution in the treatment with ultra-short implant-supported prosthesis in the posterior maxilla.