If the initial ISQ value is high, a small drop in stability normally levels out with time. A big drop in stability or decrease should be taken as a warning sign. Lower values are expected to be higher after the healing period. The opposite could be a sign of an unsuccessful implant, and actions should be taken accordingly.

Studies have shown that the resonance frequency value is greatly associated with the quantity of bone-implant contact [31, 38]. There is a positive correlation between resonance frequency analysis and histomorphometric measurements [37]. In our histological study previously reported, similar findings were demonstrated [55].

Our results indicate that both types of implants achieved primary and secondary stability.

Several measurements may be more dependable than single measures; therefore, it may be important to measure resonance frequency multiple times and average the values in order to obtain the most reliable assessment. While reliability of resonance frequency analysis has not been established in the past for these mini dental implants used for overdentures, studies have shown similar or lower levels of reliability for regular dental implants [56].

In general, there was an increase in the ISQ values in both groups, which may be related to enhancement of rigidity between the implants and neighboring tissues and largely with the changes at the bone-implant interface. It has been demonstrated that there is a development of woven bone surrounding the implants 1 week following placement in the rabbit tibia. This scantily organized bone is resorbed by osteoclasts and slowly remodeled into the lamellar bone and gets more compacted around the implant surface and remodeled to become a mature bone over a period of 42 days [38, 57]. There seems to be minimal changes in the resonance frequency after this period. Our results are in concurrence with the study by Meredith et al. [38].