Mini Implant-supported (MI-supported) anchorage is an excellent method for moving multiple teeth, en masse retraction, molars’ distalization or mesialization, molars’ intrusion or extrusion, correction of canted or tilted occlusal planes, moderate crowding, and vertical control [1,2]. As opposed to conventional implants, MIs are smaller, easier to place, and have fewer anatomic limitations [3,4]. MIs were also found to be cost effective, can be loaded immediately, and offer less post-operative discomfort, which seems to contribute to increased patients’ acceptance [5-7].

The clinical success of MIs depends on their stability at the insertion site. Generally, stability refers to the absence of mobility in the bone bed after MI placement. MIs’ stability can be divided into Primary and Secondary Stability. Primary stability (PS) refers to the degree of mechanical interlocking present immediately following MIs’ insertion [8,9]. Primary stability plays a significant role in both the short-term and longterm clinical functions of MIs [10,11]. Secondary stability, in contrast, is a biological term and relates to the degree of implant/bone osseointegration, a term coined by P.I. Branemark [12] as the direct structural and functional connection between living bone and the surface of a load-carrying implant [12,5]

Orthodontists often observe the overall stability of the MIs clinically, which is composed of both Primary and Secondary Stability. The PS of an implant decreases rapidly at first, as Secondary Stability takes over [5]. The rate at which secondary stability increases also begins to slow down after 4-5 weeks of healing [5]. When healing has occurred and the bone has remodeled, overall MI stability is primarily a function of the secondary stability [13].

The success rate of MI refers to the satisfactory clinical function during the entire period of active orthodontic treatment. Several factors contribute to the success of mini-implants in orthodontic treatment. Studies around the MIs’ design and the type of bone where the implant is placed remains conflicting, which may complicate the decisionmaking process for clinicians in terms of selecting the appropriate features of MIs [14-16]. For example, recent studies have indicated that increasing the MIs length is linked with an increase in its Primary Stability [11,17]. However, these studies base their findings on mathematical models and Finite Element Analyses, which may not be necessarily representative of clinical situations. Further, an increase in the MIs’ length is not without risk in orthodontic treatment, as longer implants may lead to the development of microcracks in bone and jeopardize the health of sinuses, nerve canals, and other vital structures in the head and neck [18]. Additionally, length was found to be irrelevant or even negatively correlated with the MIs’ Primary Stability in some studies, systematic reviews, and meta-analyses [5,19].

Similarly, conflicting recommendations seem to emerge in recent literature around the diameter of MIs, in addition to the type and density of recipient bone. For instance, one study cautioned against the use of smaller diameters given their low success rates [20]. In another study, researchers have concluded the PS of mini implants was more influenced by their length than diameter [16]. In terms of the type of bone and its thickness in the insertion site, some studies have indicated that the presence of cortical bone with a thickness of 2 mm or more is positively correlated with the PS of mini-implants [16,21]. Other studies have indicated that the thickness of cortical bone was not found to increase the PS of MIs. Rather, the presence and thickness of cancellous bone was significantly correlated with the PS and clinical success of orthodontic MIs [22,23]. This aligns with a recommendation made by researchers in a recent systematic review and meta-analysis that cautioned against assuming that cortical bone is the only predictor for PS, as evidence indicates that the presence of trabecular bone is also important, particularly in the maxilla [15]. Another limitation that is evident in many of the in-vitro and clinical studies relates to the instruments utilized to measure the MIs’ PS, which were often unavailable or too technical for clinicians in orthodontic practice setting [26,27].

Given that achieving PS appears to be the most important factor predicting the success of MIs [5,14], measuring and monitoring MIs’ stability is important and might predict the future clinical success. Generally, there are two non-invasive, quantitative methods available for measuring MI stability: the impact-hammer method (Periotes, Medizintechnik Gulden, 2018), and the resonance frequency analysis (Osstell, 1999). The impact-hammer method , Periotest is an updated and more objective version of the percussion test, which was originally developed to measure tooth mobility during the progression of periodontal disease. However, it was later found to be a reliable and non-invasive method of measuring dental implant stability [28-30]. Periotest measures the reaction of the periimplant tissues to a known magnitude of percussive force applied to the implant. The Periotest uses an electromagnetically controlled metallic tapping rod and an accelerometer to measure the contact time between the test object (implant) and the tapping rod. The contact time is then converted into an implant stability quotient, the Periotest value (PTV). The PTV ranges from −8, for low mobility (high Stability), to + 50, for high mobility (low stability).

Another non-invasive method of measuring implant stability is resonance frequency analysis (RFA) that was introduced to dentistry in 1994 by Meredith [31]. In 1999, this method of analysis has been commercially available as the Osstell^TM device, and has been one of the most commonly used methods to test the implants’ stability [32]. RFA technique is based on a small transducer that contains two piezoelectric elements and is screwed on top of the implant or its abutment [31,32]. The first element is excited in the range of 5-15 KHz, thus transmitting a harmless vibration to the bone implant interface. The response to this vibration is then registered by the second element and transmitted through an output cable to a frequency/response analyzer, which interprets the signal into an Implant Stability Quotient (ISQ). The whole operation is executed by piezoelectric transducers called Smart-Pegs that are secured to the implant. The Osstell instrument vibrates the Smart-Peg through magnetic pulses and measures the bone/implant interface RF. The RF response is presented into ISQ, which ranges from 1 to 100. The higher values are indicative of better implant stability.

In summary, there seems to be convincing evidence with conventional dental implants that factors such as implant diameter, length, bone quality, and denisty influence PS [5]. However, recent systematic reviews and meta-analyses have flagged this inconsistency in findings and called for a closer examination of the MIs’ design features and quality of bone in insertion sites in in-vitro models [15]. This investigation is critical to inform future in-vivo studies and clinical trials in investigating other factors, including patient-dependent factors such as age, sex/gender, and oral hygiene effectiveness [20]. Therefore, this study aimed to investigate the effect of MIs’ diameter, length and the presence of cortical bone on the PS of MIs, using two commercially available non-invasive implant stability-measuring devices. The knowledge obtained from this experiment could provide valuable information for clinicians to formulate an optimal treatment plan, increase the success rate of MI and prevent unnecessary trauma to adjacent vital anatomical structures. Our hypothesis posits that variations in mini-implant diameter, length, and cortical bone density will have a significant influence on the MIs’ Primary Stability during orthodontic treatment.

2.1. Bone blocks

Graded porous polyurethane-bone-blocks (Sawbones Corporation, Vashon Island, Washington, USA) with densities similar to cancellous-bone (GP20 – density of 0.32 grm/cc) were used to simulate soft trabecular (cancellous) bone (Figure 1). In order to reproduce the heterogeneous nature of the jawbone, 1 mm and 2 mm of hard polyurethane sheets (GP50 – density of 0.80 grm/cc), which simulated the density of the cortical bone, were laminated over the GP20 bone block, as per the manufacturer’s instructions (GP20-1 mm CB) & (GP20-2 mm CB). The three types of artificial bone blocks used in this experiment simulated mechanical characteristics of the cancellous bone also known as the trabecular bone, as well as those of heterogeneous bone types commonly found in the jaw. The uniform density of these blocks offers less variation in contrast to the animal or post-mortem cadaver bone models, where bone demonstrates significant variation across anatomical sites or animal species. Simulated bone blocks are also less costly, easier to maintain and allow large data collection without loss of any animals or use of hard-to-maintain cadaver bone.

Figure 1. Photographs show Sawbones Corporation bone blocks simulating–cancellous bone GP20 (a) and heterogeneous bone with 1 mm hard polyurethane sheets GP20-1mm CB (b). Rows of MIs placed in pre-prepared sockets in Sawbone blocks (c), (d).

2.2. Mini-implants (MIs)

There are several designs of MIs available on the market. MIs used in this study were provided by AbsoAnchor (Dentos Inc, Daegu, South Korea). These implants are made of titanium alloy (Ti6Al4V) and have a slight taper with an aggressive thread pattern (SH 1312-05). They also have a particular joint-head design with inner threads that allow the connection of magnetic Smart-Pegs needed for ISQ stability measurements using the Osstell device (Fig. 2).

Figure 2. Customized Osstell^TM smart peg secured to an AbsoAnchor MI (a), and Customized smart peg installed in an AbsoAnchor mini-implant placed in a simulated GP20-1mmCB bone block (b).

A total of one hundred and eight AbsoAnchor MIs, consisting of three commonly used lengths (6 mm, 8 mm, 10 mm) and three diameters (1.5 mm, 1.7 mm, 2 mm) were placed into synthetic bone blocks. MIs were placed in blocks with densities of cancellous bone (GP-20) and in blocks that were sandwiched with either 1 mm or 2 mm polyurethane sheets, which simulated cortical bone density. Four MIs in each group were placed according to the manufacturer’s recommendations. A Straumann (Straumann Holding AG, Basel, Switzerland) torque wrench and a designated adaptor were used to record the maximum insertion torque.

2.3. Socket preparations

Some MIs’ manufacturers recommend free hand placement without pre-preparation of an osteotomy socket (pre-drilling), given that MIs placed this way could demonstrate more PS compared to those placed in pre-prepared sockets. Nevertheless, this method may lead to uncontrolled implant path, consequently causing unnecessary injuries to adjacent structures. The manufacturer of the AbsoAnchor provides designated pilot drills and recommends undersize pre-preparation of the implant bed prior to MIs’ placement.

For all experiments in this paper, MIs’ sockets were prepared one centimeter apart from each other using designated pilot drills and an automated Computer Numerical Control (CNC) machine (HAAS Mini Mill, Zaventem, Belgium). New MIs were then placed in each pre-drilled bed using a torque wrench (Straumann torque wrench) and a designated adaptor.

Each bone block received a total of 36 pre-prepared sockets in three rows of twelve sockets per row. MIs were hand tightened first and then further tightened by the torque wrench until the heads of the MI became flush with the surface of the bone block.

2.3.1. Data Collection

PS values of all MIs were measured by three testers, using both Periotest and Osstell^TM. The clinical application of the Periotest device is straightforward, as the device generates one PerioTest Valuve (PTV) for each cycle of measurement. The Periotest has a handpiece and an automated tapping device that touches the implant when it comes in close proximity of the implant surface. Erroneous readings were automatically discarded and the total average of fourteen measurements were calculated at the end of each measuring cycle. The Periotest readings were obtained by holding the handpiece perpendicular to the long axis of the MI.

Osstell ISQ measures the RFA response at the MI-bone interface. The device uses a prefabricated magnetic Smart-Peg that must be hand-tightened to the coronal threads of the implant. The Osstell^TM device was originally designed to measure the stability of conventional dental implants that have wider coronal diameters than MIs. Unfortunately, we could not find a suitable factory-recommended Smart-Peg among the list provided by Osstell^TM that can securely fit the inside threads of the AbsoAnchor MIs. The closest Smart-Peg that was recommended by Osstell was a modified Type 2 Smart-Peg fabricated with similar matching threads to that of AbsoAnchor. However, these pegs were very loose-fitting and became progressively looser after one or two uses. As a solution, custom-made pegs were fabricated by press-fitting matching stainless steel screws to the magnetic body of a Type 2 Smart-Peg. This procedure involved removal of the existing connecting screw hold of the Osstell Smart-Peg and replacing it with a new connecting screw that matched the MI inside thread accurately. The accuracy of the ISQ readings of all customized Smart-Pegs was tested on a sample MIs that was secured in a controlled three-prong vice that provided maximum stability. The performance of the customized pegs was tested while one or two holding prong blades were loosened sequentially to decrease the maximum holding force. This method provided a controlled system in which the responses of each customized peg could be tested. The ISQ readings were plotted against the magnitude of the holding force reduction for each customized peg. All customized pegs that did not show a direct reduction in ISQ in response to the prong blades loosening were discarded. A total of eleven customized pegs were fabricated and used in this study that demonstrated similar performance at the three-prong controlled stability setting. Each customized Smart-Peg was used for ISQ measurements of ten MI before discarding.

Data was collected when the blocks were secured to the bench with a holding wrench. Each PTV and ISQ measurement was repeated by three testers. The average of the three measurements for each examiner were recorded in an Excel spread sheet for statistical analysis.

2.3.2. Data Analysis

Data were exported imported into SPSS version 28 (IBM, New Orchard Road, Armonk, New York). Inter-examiner reliability for the Periotest and Osstell^TM was calculated using the Cronbach Alpha reliability test. Normal distribution of the data of each variable was tested using the Shapiro-Wilk test and Q-Q plots to visualize the normality of the data. A multifactorial ANOVA test was first conducted to investigate the effects of the MI length, diameter and the cortical bone sheet on the MIs’ Primary Stability. Finally, two-way ANOVA with Boneferroni post-hoc tests were performed to observe the trend of PS change in each bone block. The significant level value was set at (α=0.05).

A source of variation in the data collection may occur if implant sockets are prepared manually. This was addressed by using a designated pilot drill and an automated CNC machine. The computer-controlled drill created consistent implant osteotomy sockets exactly one centimeter apart. The integrity of each socket was inspected and confirmed with a magnifier (4X) prior to the MIs’ placement. All 108 osteotomy sockets created by the CNC machine were considered uniform and acceptable for MIs’ placement.

The original Smart-Pegs provided by Osstell that was expected to closely match the inner threads of the AbsoAnchor (SH 1312-05) were designed primarily for conventional dental implants. We found these Smart-Pegs became progressively loose-fitting after 1 or 2 uses. This resulted in inconsistent and overall low ISQ readings (≈ 30) in all blocks. The custommade pegs were found to be secure and reliable after multiple tests in the three-prong controlled stability measuring system. Nevertheless, they were discarded after ten-time uses to prevent any chance of excessive thread wear and erroneous ISQ readings. The custom-made pegs reduced excessive ISQ variation and increased overall ISQ values (≈ 65) specially in heterogeneous bone blocks indicating that the custom-made pegs functioned more consistently than the optional Smart-Peg available in the current Osstell catalogue (2016).

All MIs were installed according to the manufacturer’s recommendations. A Straumann torque wrench and a designated adaptor (Straumann Holding AG, Basel, Switzerland) were used to place all MIs. The average final torque was measured to avoid excessive torsional forces that could distort or fracture MI during placement. The placement torque was consistent in each group of MI placed and indicated different values only in different bone blocks and in MI with different diameters. The mean final placement torque values are given in the Table 1.

Table 1 Placement torque values of Mini-implants (MI)

MI Diameter -mm	GP20/N-cm	(GP20-1mm CB)/N-cm	(GP20-2mm CB)/N-cm
1.5	5 ± 0.5	15 ± 0.8	23 ± 2
1.7	5 ± 0.8	20 ± 0.5	25 ± 1
2	6 ± 0.8	22 ± 0.8	27 ± 0.5

The three examiners were trained to use the Periotest and Osstell^TM as per manufacturer’s instructions. The Cronbach Alpha inter-examiners reliability test indicated a strong correlation in the range of 0.98- 0.99 for the Periotest (p < 0.0001). The range for Osstell showed more variation; nevertheless, it demonstrated a clinically acceptable range of correlation between 0.75-0.97 among the examiners (p < 0.0001). This inter-examiner reliability data indicated that both devices were relatively easy to learn and apply in our model.

The null-hypothesis for the Shapiro-Wilk test was accepted for both Periotest PTV and Osstell ISQ data indicating that data were normally distributed. Therefore, a parametric test of analysis of variance was applied to all variables. Data were analyzed with Multifactorial ANOVA first to screen for statistical differences and potential interactions among variables.

Both MI-related factors of length and diameter, as well as bone block type resulted in statistically significant (p < 0.05) differences in stability measurements with both Periotest and Osstell^TM. In terms of the interactions between the variables, there was a statistically significant interaction between the variables of the MIs’ diameter, length, and bone block type (p < 0.05). However, the interaction between the two variables of the MIs’ length and diameter was not statistically significant. This pattern of interactions where the bone block type seemed to drive the statistically significant difference indicated that MI length and diameter interacted with the bone block differently and in a unique manner. Therefore, two-way ANOVA tests were conducted for both the Periotest and Osstell^TM results in different bone blocks to identify the unique interactions of MI diameter and length in the three simulated bone block.

In GP20 (cancellous bone), both Periotest and Osstell^TM indicated statistically significant increases (p < 0.05) in PS when both the diameter and length of MI increased. The increase in PS relationship to diameter and length was more pronounced in the small diameter (6 mm) MIs (Fig. 3).

Figure 3. Box plots show range of data for Periotest PTV and Osstell ISQ for different MI length and diameter in GP-20 (simulated cancellous bone). The Y axis shows the measured ISQ or PTV values and the connected lines between box plots indicate statistical differences with corresponding p values.

When the same tests were conducted on results obtained with the Periotest and Osstell^TM in sandwiched bone blocks (GP20-1mmCB & GP20-2mmCB), only an increase in MIs’ diameter appeared to result in a statistically significant (p < 0.05) increase in PTV and ISQ. In these blocks, there was no statistically significant difference in PS when the length of the MI increased (Fig. 4 and Fig. 5).

Figure 4. Box plots show range of data for Periotest PTV and Osstell ISQ for different MI length and diameter in GP20-1mmCB (simulated heterogenous bone with 1 mm thick cortical thickness). The Y axis shows the measured ISQ or PTV values and the connected lines between box plots indicate statistical differences with corresponding p values.

Figure 5. Box plots show range of data for Periotest PTV and Osstell ISQ for different MI length and diameter in GP20-2mmCB (simulated heterogenous bone with 2 mm thick cortical thickness). The Y axis shows the measured ISQ or PTV values and the connected lines between box plots indicate statistical differences with corresponding p values.

This laboratory research paper aimed to address a knowledge gap in terms of the factors that contribute to the success of Mini-Implants (MIs) in orthodontic practice. Specifically, we studied the effect of MIs’ design factors, including length, diameter, as well as bone type on the Primary Stability of one commercially available MI. Although the use of Mini-Implants is becoming increasingly popular in contemporary orthodontic treatments as a reliable anchorage strategy to resist unwanted tooth movements [2,5], MIs may have to be replaced during the typical course of the orthodontic treatment [33], and may not enjoy the high success rate of conventional implants in some clinical situations [34]. Emerging evidence suggests that the primary predictor of an implant’s ultimate success, whether conventional or mini, is their degree of primary stability (PS) in the bone at the time of placement [5,15]. Therefore, this work offers evidence around the factors that can enhance the PS of MIs, and consequently, increase their clinical success rates.

There is convincing evidence with conventional implants that both implant design factor and bone type can increase PS [35-37]. However, the effects of these factors in stability of Mini-Implants is not fully understood [38]. When examining the results of our study, we found that both diameter and cortical bone thickness appear to significantly improve PS in MI placed in polyurethane simulated bone blocks. However, the MIs’ length was not found to be a contributing factor in the PS of MIs in cortical, dense bone. This is consistent with other studies that investigated 260 different MI designs and concluded that MI diameter, tapering, thread design and cortical bone thickness can influence PS [23]. The authors did not find any significant difference in PS between MI with 6 mm and 9 mm lengths. Similarly, a systemic review by Marquezan et al. reported a positive association between cortical bone thickness and MI stability; however, they also acknowledged a lack of well-designed clinical trials to investigate PS [39]. In another study, diameter and angle of placement of mini-implants were found to be more important than length for anchorage and implant stability [40].

In an interesting divergence, our findings indicate that an increased length of the MI has increased the PS of MI in one case: when the MIs were place in soft cancellous type bone. As we indicated earlier, length did not have any significant effect on PS in heterogeneous 1-2 mm cortical sandwiched bone blocks. This finding is in contrast with Mohlhenrich et al.’s invivo study, which reported that length was the most significant factor in increasing the PS of mini-implants placed across different anatomical areas of the maxilla, with varying thickness of cortical bone [26]. Other studies, both clinical and ex-vivo, also seem to advocate for an increase in the MIs’ length, and argued that anatomical restrictions may limit the orthodontists’ ability to control the MIs diameter to increase PS [41,42]. In a separate study, Chatzigianni et al. [43] study concluded that the amount of perpendicular force applied on the MIs played a key role in determining the impact of the MIs’ length and diameter on its PS. However, Shiffler et al. [44] study indicated that the increase of the dental implants’ length did not contribute to a statistically significant difference in its PS. Such discrepancies across different studies may be attributed to the impact of other confounding variables, including the MIs’ brands, models, and the study protocols. In all cases, the conflicting evidence around the role of the MI’s length in achieving PS should prompt clinicians to evaluate the bone’s density and anatomical limitations to plan an optimal length of MIs they select for orthodontic anchorage. Further, a key takeaway of our study is that MIs’ diameter seems to be the important design factor that influences PS in all types of simulated bone tested.

Another contribution of our study is the use of both Periotest and Osstell^TM as non-invasive and objective mini-implant stability measuring devices. The devices were developed to measure damping (Periotest) and vibration (Osstell) characteristics of the bone implant interface [30]. While both systems have been extensively used in research and clinical practice to record stability of conventional dental implants [45,46], there is a paucity in studies examining their application in measuring stability of MIs. In our experiment in measuring the PS of MIs in different bone blocks, the measurements from both devices were in agreement, where Primary Stability was found to increase when the MI diameter increased or when 1 mm and 2 mm simulated cortical bone layers were added to the porous polyurethane blocks. This is in line the few published studies on Periotest and Osstell^TM, which have indicated consistent and repeatable measurement of stability of MIs for both devices [27,35,47].

In addition to our study’s contribution in providing empirical evidence on the factors influencing the MIs’ PS and the consistency among measurement methods, we also offer practical tips and insights with regards to the measurement process. For instance, the Osstell^TM is limited by a design restriction, as it requires an electromagnetic exciter probe and a dedicated Smart-Peg, which must be screwed into an implant [31]. This way, the vibration characteristics of the bone implant interface can be measured from its resonance frequency [31]. However, most MIs are not designed with inner threads at the coronal part to receive Smart-Pegs [47]. Our experiment was a case in point, as we have selected AbsoAnchor’s design, which has a unique coronal inner thread that was supposedly compatible with specific orthodontic brackets as well as a Smart-Peg. Unfortunately, the Type 2 Smart-Peg recommended by Osstell for AbsoAnchor MI did not function as expected and loosened after the first attempt to install it into the inner threads of the AbsoAnchor MI. The ISQ measurements were thus inconsistent and not repeatable. Therefore, we modified the pegs by replacing the existing connecting screw hold with a new stainless steel screw that matched the MI inner coronal threads precisely. The Smart-Peg modification has been performed in other studies as well to improve accuracy; however, a certain level of detail to support researchers in replicating these modifications was lacking [47,48]. It is feasible that a mismatch of threads between a Smart-Peg and AbsoAnchor was responsible for early loosening of the pegs. It is also possible that the differences of material hardness between the soft metal of the Smart-Pegs and the hard titanium alloy (Ti-6Al-4V) of AbsoAnchor caused premature wear of the peg threads. In agreement with the later possibility, Osstell also acknowledges that Smart-Pegs are made from a soft metal with a zinc-coated magnet mounted on top. The Smart-Pegs will therefore rapidly wear after being opened (Osstell, 1999). Our modifications produced a hybrid peg by using a custom precise-fitting screw-hold that allowed the magnetic portion of the peg to vibrate. The consistency of these modified pegs was successfully tested before use in a three-prong vice hold and showed predictable reduction of ISQ values as individual vice arms loosened sequentially.

Our study is not without its limitations. In this experiment, we only investigated the effects of length and diameter of the MIs as well as the contacting bone type on PS. The influence of other parameters of MI, such as thread design, pitch size, tapers, surface topography, and different materials on PS should also be studied in detail in future research. Recognizing the factors that contribute to improving PS can decrease unnecessary trauma, premature MI failure, and costly retreatments in recipients of these implants, who are mainly children and adolescents [5]. Although MI are smaller than conventional dental implants, they are often placed in anatomically restricted areas between posterior teeth in the maxilla and mandible. Therefore, careful planning with advanced imaging tools such as cone-beam computed tomography (CBCT) should assist mapping anatomical complexity and available bone type. The results of this simulated study can inform clinicians when selecting optimal MI for available anatomical space and bone types to ensure maximum Primary Stability (PS).

This study utilized a simulated model that may not be transferrable to in vivo or clinical settings. Nevertheless, simulation models are excellent in providing preliminary results that can guide more systematic well-designed in vivo experiments to investigate the effects of MI design and bone factors on the PS. Detailed diagnostic and quantitative imaging tools such as micro and Cone-Beam Computed Tomography (CBCT), are required to map the bone of the recipient sites for MI.

This study investigated the effects of MI design factors including length, diameter, as well as bone type on the Primary Stability (PS) of a commercially available Mls. Within the limitation of this in vitro study, the results have demonstrated that the PS of AnsoAnchor orthodontic MIs can be affected mainly by an increase in diameter as well as the type and density of the contacting bone. The increase of the length of the MIs only contributed to an increase in the MI’s PS in soft cancellous bone. The result of this simulated study should provide a guideline for selecting optimal MI for available anatomical space and bone type in order to maximize Primary Stability.

Thanks are extended to Prof. Hee-Moon Kyung of Kyungpook University (South Korea) for generous donation of all AbsoAnchor mini-implants used in this research and for providing valuable technical advice for fabricating customized smart pegs. In addition, we would like to thank Mr. Rob Dodsworth of Citagenix, for technical support and providing Osstell’s Smart-Pegs.