Development of Implant Stability Quotient values of implants placed with simultaneous sinus floor elevation - results...

In patients with implant placement and simultaneous sinus floor elevation (SFE), healing periods of 6 months have been the standard of care for more than 25 years. The primary objective of this prospective case series study was to determine what percentage of implants placed with SFE reach a threshold Implant Stability Quotient (ISQ) of ≥70 after 8 weeks of healing using Resonance Frequency Analysis (RFA).

A total of 109 dental implants were placed in 97 patients. SFE was carried out with a lateral window approach and a mixture of autogenous bone chips and deproteinized bovine bone mineral (DBBM). Titanium screw-type, tissue-level implants with a chemically modified SLA surface were used. ISQ values were measured after implant insertion (ISQ_BL ) and after 8 weeks of healing (ISQ_8 wk ). Patients showing ISQ_8 wk  ≥ 70 subsequently underwent restoration. Implants with an ISQ value < 70 were recalled at 2-week intervals.

The ISQ at baseline had a mean value of 68.3 (SD ± 9.8). At 8 weeks, the mean ISQ value was 73.6 (SD ± 6.4). This increase was statistically significant (P < 0.001). An ISQ_8 wk value ≥70 was observed for 91 implants (83%). One implant (0.9%) with a peri-implant infection and severe bone loss at 8 weeks was considered an early failure.

This study showed that 83% of implants reached the threshold level of ISQ ≥ 70 after 8 weeks, allowing an early loading protocol. The early failure rate was considered low with 0.9%. The RFA technology is a suitable method to objectively monitor implant stability longitudinally.