The Internal Sinus Floor Elevation Procedure is Comparable to the Conventional Sinus Floor Elevation Procedure in Highly Atrophic Alveolar Ridges: Results Four Years after Loading in A Randomized, Controlled, Blind Pilot Study

To investigate whether endoscopically assisted internal sinus
floor elevation (EIS) is as good as the conventional open
surgical method (CSE) in terms of sufficient bone support for
the placement of dental implants and long-term implant
success. A split mouth model whereby 20 dental implants were
installed in 10 patients (five female and five male) following EIS
or CSE. No graft materials were used, only locally harvested
autogenous bone. Both surgical procedures were monitored
endoscopically at the time of implant placement and upon
placement of the healing abutment (three months). Panoramic
radiographs were made pre- and postoperative, and after 36
months in order to evaluate peri-implant bone. The average
preoperative maxillary alveolar bone height at the implant site
(first molar) was 4 mm. The average gain in bone height was 6
mm using EIS and 5.5 mm with CSE respectively. Clinical
parameters revealed sufficient implant stability at the time of
placement. Three implants failed during the healing period of
12 weeks. The overall implant success rate was 85 percent.
The overall success rate at the time of implant loading was 100
percent. After loading, no further implant failure was observed
over a four year period. Sinus floor elevation is a wellestablished
procedure for augmentation of the atrophic
maxillary posterior region. Our results indicate that EIS is at
least as good as CSE. Endoscopically assisted surgery helped
prevent, diagnose, and manage sinus membrane perforations.
After 48 months of loading, the clinical outcomes of the present
study showed that EIS and simultaneous implant placement
resulted in low intraoperative trauma, sufficient implant stability
upon placement, low incidence of postoperative symptoms,
and a high success rate.