Validation of an implant stability measurement device using the percussion response: a clinical research study

In recent years, the use of dental implants has become widespread in the field of dentistry, and various technological advancements have been proposed to improve treatment outcomes [1‐3]. For instance, several devices have been developed to measure implant stability as an indicator of the success of implant treatment. The Osstell® device [4] allows the measurement of the implant stability quotient (ISQ) using the resonance frequency analysis (RFA) method, whereas the Periotest® device [5] uses the percussion method. More recently, the AnyCheck® device, which also relies on the percussion method, has been developed [6]. Importantly, the insertion torque (IT) of the implant into the bone influences the success of implant treatment; therefore, the ability of these devices to quantify and evaluate implant stability has contributed greatly to the success of implant treatments [7, 8], benefitting both dentist and patients. There are two types of implant surgery: those that allow submerged implant healing and those with non-submerged implant healing. Submerged implant healing is often considered when the primary stability is poor or when bone grafting has been performed [9]. In non-submerged implant healing, removal of healing abutments prior to superstructure placement has been reported to be a cause of accelerated bone resorption [10]. Therefore, the concept of “one abutment–one time,” in which the abutment is placed immediately after implantation to control bone resorption, is popular [11]. Despite its long history of use, the Osstell® device requires removal of the healing abutment and the attachment of smart pegs. Of note, AnyCheck® does not require the healing abutment to be attached or removed; therefore, it can measure implant stability without promoting bone resorption. Although there have been various reports on implant stability, thus far, no study has compared the ISQ and implant stability test (IST) values in clinical practice [12]. To address this gap in knowledge, the present study aimed to investigate the correlation between implant stability for the Osstell® and AnyCheck® devices.

The IST values immediately, 1 week, 2 weeks, 3 weeks, 4 weeks, and 6 weeks after implantation were 81.0 ± 2.82, 79.1 ± 2.87, 79.7 ± 2.83, 80.5 ± 2.71, 80.9 ± 4.0, and 82.4 ± 2.65, respectively. The ISQ values immediately, 1 week, 2 weeks, 3 weeks, 4 weeks, and 6 weeks after implantation were 79.8 ± 2.89, 76.0 ± 2.8, 77.8 ± 2.63, 79.2 ± 2.44, 79.7 ± 2.77, and 80.2 ± 2.35, respectively (Fig. 3). Of note, both the IST and ISQ values decreased the most in the first week after surgery and increased in the second week; additionally, the IST value was slightly higher at all measurement points. The Spearman’s rank correlation coefficients for each measurement period were as follows: r = 0.64 immediately after implantation; r = 0.29 at 1 week; r = 0.68 at 2 weeks; r = 0.53 at 3 weeks, r = 0.68 at 4 weeks, and r = 0.56 at 6 weeks. A positive correlation was found in all cases, except at 1 week when the correlation was weak (Fig. 4).

This study compared the changes in implant stability using the Osstell® and AnyCheck® devices. Our analysis indicated that the measurements exhibited a positive correlation of > 0.5, except after 2 weeks. This suggested that AnyCheck® had the same performance as Osstell®.

When the IT is high, bone resorption is promoted. Optimization of the IT is considered the key to successful implant treatment [13‐15]. In this study, all the implants had an IT of 35 Ncm. However, even in cases of low IT, the use of AnyCheck® allows safe assessment of implant stability. The IST and ISQ values in this study were high. Zwaan et al. [16] placed 163 implants in the maxilla and compared the IT at 50 Ncm, 40–45 Ncm, 30–35 Ncm, and ≤ 30 Ncm and found that the ISQ values were 76.2 ± 5.3, 72.3 ± 5.3, 70.0 ± 6.7, and 68.1 ± 6.2, respectively. The ISQ values were also reported to be higher for tapered implants than for straight implants. Van Eekeren et al. [17] compared bone-level with tissue-level implants and revealed that the ISQ values (at the time of placement and 2, 3, and 12 weeks postoperatively) were 77.8, 75.6, 76.3, and 79.1, and 74.0, 71.8, 72.6, and 76.8, respectively. Importantly, the above results suggest that ISQ values tend to vary according to bone quality, implantation site, and implant shape, in line with the findings reported elsewhere [18]. As reported above, the authors of this study think that the high value was due to the use of bone-level and tapered implants. Oates et al. [19] reported that the stability of SLActive® implants changed from a decrease to an increase at 2 weeks after placement, in line with our results. In the present study, the weakest correlation was observed after 2 weeks. This may be explained by individual differences in the decline of primary stability, resulting in large differences in IST and ISQ.

Park et al. [6] placed an implant into an artificial bone block to verify the accuracy of AnyCheck®; interestingly, the stability decreased as the height of the healing abutment increased and as the contact angle decreased from 30° to 0° (perpendicular to the long axis of the implant and parallel to the ground). Subsequently, Lee et al. [20] placed implants at 10 N, 15 N, and 35 N into artificial bone blocks together with five different diameters of healing abutments of the same height, measured the IST values using AnyCheck®, and compared them with the ISQ values determined using Osstell®. Importantly, they reported that the diameter of the healing abutment did not affect the ISQ and IST values, which exhibited a strong correlation. Consistent with these results, Lee et al. [21] also found that the results for the AnyCheck® and Osstell® devices were correlated in the context of both internal-connection and external-connection implants (within pig bone). Of note, they also reported that the IST values were higher for both implants and that there was no significant difference between the IST and ISQ values. However, neither the IST nor the ISQ values are known to be accurate; they should only be considered as one among several indicators.

In clinical practice, Al-Jamal et al. [22] demonstrated that there was a significant correlation between primary stability and IT using the AnyCheck® device in the context of 40 implants. However, they did not compare their findings with measurements obtained using the Osstell® device. The present study is the first in which the IST and ISQ values were measured and compared weekly in clinical practice, from immediately after implantation to 4 weeks later. While the Osstell® is a device with a long history of use and has been explored in many studies to date, its use requires removal of the healing abutment and attachment of the smart peg. The recently released Osstell Beacon® is cordless. However, as before, it still requires a smart peg, and the healing abutment must be attached and removed. Esposito et al. [23] reported that the removal of the healing abutment (three times after implantation until the time of superstructure attachment) led to 0.16 mm of bone resorption per year (versus non-removal of the healing abutment). Similar results were obtained by Bressan et al. [24]—0.43 mm of bone resorption over 3 years in healing abutment removal versus non-removal contexts—as well as by Koutouzis et al. [25]—0.13 mm versus 0.28 mm bone resorption in 6 months after implantation in the without versus with healing abutment removal context). Importantly, AnyCheck®, which allows the measurement of stability without the need to attach or to detach the healing abutment, reduces bone resorption and can be applied to low-torque cases. In the present study, a positive correlation of > 0.5 was observed at all measurement points, except after 2 weeks. Considering the risk of bone resorption and other factors, the AnyCheck® is expected to perform as well or better than the Osstell®. Since there are no reports comparing the two devices in clinical practice, further validation of this matter is necessary. Furthermore, this study has some limitations. The sample size for this study was small. This was due to the limited number of patients in whom implants of the same system, diameter, and length were placed. In addition, in vitro studies cannot assess changes in implant stability over time. Therefore, studies using models could not be conducted previously. In the future, it is necessary to distinguish between bone quality and implant diameter to obtain more detailed data.

The ability to assess implant stability without removing the abutment during healing is essential for determining the time at which load can be applied without the risk of bone resorption. Altogether, our results suggest the similar performance of Osstell® and AnyCheck®, and, consequently, the usefulness of the latter for the determination of implant stability.