In contrast to mandibular cases, treatment plans for implant placement in the maxillary posterior region are often restricted by the presence of the maxillary sinus. We examined the surgical techniques and treatment results of dental implants placed in the maxillary posterior region using socket lift procedures performed during a 6.5-year period from the establishment of our clinic on October lst, 1997 to March 31st, 2004.
Out of 44 cases involving 85 implants, socket lift procedures were performed in 31 cases and for 50 implants (58.8%). When performing a socket lift procedure, we first measured the vertical residual bone height (RBH) between the alveolar crest and the maxillary sinus floor. Postoperatively, we measured the elevated height (E-H). The RBH values were between 4 and 8 mm, with an average of 6.1 mm. The E-H values were between 2 and 7 mm, with an average of 5 mm. RBH values were divided into the categories RBH-1 (less than 4 mm), RBH-2 (5-7 mm) and RBH-3 (greater than 8 mm), while E-H values were divided into categories E-H1 (1-3 mm), E-H2 (4-6 mm) and E-H3 (greater than 7 mm). The results of this classification were as follows: RBH-1,10 implants; RBH-2,30 implants; RBH-3, 10 implants; E-H1, 13 implants; E-H2, 30 implants; E-H3, 7 implants. After sinus floor elevation by the socket lift procedure, 50 implants were installed in the maxillary posterior regions of the 31 cases. The superstructures were placed on the 30 implants, two of which were lost after occlusal loading. Of the other 20 implants, 18 were embedded in the maxilla, and 2 were lost before the second-stage surgery. Therefore, the five-year accumulated survival rate of the implants placed using the socket lift procedure was 89.5%.
From these results, the socket lift procedure can be considered a useful surgical technique for patients with a severely resorbed maxilla.