Prospective, Clinical Pilot Study with Eleven 4-Mm Extra-Short Implants Splinted to Longer Implants for Posterior Maxilla Rehabilitation

Abstract

In many clinical situations, rehabilitation with implants in the posterior maxillary region is complicated by limited bone availability. In this context, the use of 4 mm long implants (known as extra-short implants) may be used thanks to the concept of osseointegration enhancement. It has been demonstrated that short implants offer an alternative to the regeneration procedures involved in placing longer implants in areas where bone height is compromised. This prospective pilot study tested a treatment protocol in which 11 extra-short (4 mm) implants were splinted to 11 mesially placed longer (8 mm) implants in the posterior maxillary regions of partially edentulous patients, without using supplementary bone regeneration procedures. Eleven patients were included in this single cohort study. The clinical performance of the extra-short implants was assessed during a two-year follow-up period, obtaining a 100% survival rate and mean bone loss of 0.3 mm. Implant stability measured by resonance frequency analysis (RFA) at the time of placement was 54.9 ± 4.9, increasing to 77.0 ± 2.6 at 24 months. The study demonstrated the gradual consolidation of osseointegration in bone of less-than-ideal quality in the posterior maxillary region. The results obtained show that a partially edentulous maxilla with reduced bone height may be rehabilitated by using an extra-short implant splinted to a mesial implant of 8mm length or longer. Despite the small sample size, this pilot study observed that extra-short implants achieved adequate bone stability and clinical performance after a 24-month follow-up.

Keywords: extra short implant; osseointegration enhancement; posterior maxillae; short implant; splinted; treatment protocol.

Figure 1

References for MBL and CBL measurements: CBL, red; implant shoulder (IS), green; implant shoulder to first point of bone-to-implant contact (IS-BIC), yellow.

Figure 2

Custom bite blocks for periapical radiographs.

Figure 3

Radiograph of extra short and long implants at implant placement.

Figure 4

Radiograph of extra short and long implants at 12-month follow-up.

Figure 5

Radiograph of extra short and long implants at 24-month follow-up.

Figure 6

(a) Clinical spam of missing teeth; (b) long and extra-short implants in place; (c) variobase abutments screwed to the implants; (d) ceramic crowns in place.

Figure 7

Lateral view of implant crowns.

Figure 8

Schematic distribution of ISQ values by evaluation time and implant type.

Figure 9

Bone tissue remodeling value distribution by stage and implant type.