Biomechanical evaluation of oversized drilling technique on primary implant stability measured by insertion torque and resonance frequency analysis

Dental Implant with Porous Structure and Anchorage: Design and Bench Testing in a Calf Rib Model Study

Primary dental implant stability is critical to enable osseointegration. We assessed the primary stability of our newly designed dental implant. We used the calf rib bone animal model. Our implant has an outside tapered screw with two inside barrettes that deploy with a second screw situated at the implant's crown. We used ten calf ribs with III/IV bone density and inserted ten implants per rib. We deployed the barrettes in the calf rib's transversal direction to support against the nearby cortical bone. We measured the primary implant's stability with resonance frequency analysis and collected the Implant Stability Quota (ISQ) in the transverse and longitudinal calf rib planes before (PRE) and after (POS) deploying the barrette. The mean ISQ was PRE 84.00 ± 3.56 and POS 84.73 ± 4.53 (p = 0.84) in the longitudinal plane and PRE 81.80 ± 2.74 and POS 83.53 ± 4.53 (0.27) in the transverse plane. The barrettes' insertion increases our dental implant primary stability by 11% in the transverse plane and 2% in the longitudinal plane. Our dental implant ISQ values are in the higher range than those reported in the literature and reflect high primary stability after insertion. The barrette deployment improves the dental implant's primary stability, particularly in the direction in which it deploys (transverse plane).

Evaluation of the primary stability in dental implants placed in low density bone with a new drilling technique, Osseodensification: an in vitro study

Background

Primary stability is an important key determinant of implant osseointegration. We investigated approaches to improve primary implant stability using a new drilling technique termed osseodensification (OD), which was compared with the conventional under-drilling (UD) method utilized for low-density bones.

Material and Methods

We placed 55 conical internal connection implants in each group, in 30 low-density sections of pig tibia. The implants were placed using twist drill bits in both groups; groups Under Drilling (UD) and Osseodensification (OD) included bone sections subjected to conventional UD and OD drilling, respectively. Before placing the implants, we randomized the bone sections that were to receive these implants to avoid sample bias. We evaluated various primary stability parameters, such as implant insertion torque and resonance frequency analysis (RFA) measurements.

Results

The results showed that compared with implants placed using the UD technique, those placed using the OD technique were associated with significantly higher primary stability. The mean insertion torque of the implants was 8.87±6.17 Ncm in group 1 (UD) and 21.72±17.14 Ncm in group 2 (OD). The mean RFA was 65.16±7.45 ISQ in group 1 (UD) and 69.75±6.79 ISQ in group 2 (OD).

Conclusions

The implant insertion torque and RFA values were significantly higher in OD group than in UD. Therefore, compared with UD, OD improves primary stability in low-density bones (based on torque and RFA measurements).

Key words:Osseodensification, primary stability, low density bone, RFA.

Does the Modification of the Apical Geometry of a Dental Implant Affect Its Primary Stability? A Comparative Ex Vivo Study

(1) Background: Primary stability—one fundamental criterion for the success of dental implants—is influenced by implant geometry even if the effect of apical shape modifications on implant primary stability has not yet been examined. Therefore, the aim of the ex vivo study was to compare primary stability of implants differing in apically located screw threads (J-line) or a flat tip (K-line) only. (2) Methods: 28 implants of each group of the same diameter (4.3 mm) were randomly inserted into porcine bone blocks. The first group (9, 11 and 13 mm) was inserted into “hard”, the second (11 mm) into “soft” bone, here using a normal and an undersized drilling protocol. Insertion torque (Ncm), Periotest^® value, resonance frequency (implant stability coefficient, ISQ) and push-out force (N) were measured. (3) Results: In “hard” bone, primary stability increased with increasing length in both groups but it was significantly higher in J-line (p < 0.03). An undersized preparation of the implant bed in “soft” bone resulted in a significant increase in primary stability in both groups. Here, J-line also showed a significantly increased primary stability when compared to equally prepared K-line (insertion torque: 37 Ncm vs. 26 Ncm; Periotest^®: −6.5 vs. −4.3; push-out force: 365 N vs. 329 N; p < 0.05 each). (4) Conclusions: Primary stability is significantly higher with increasing implant length and apically located screw threads as well as with undersized drilling protocols. When preparing the implant site and subsequently selecting the implant system, modifying factors such as implant geometry (also at the tip) should be taken into account.

Comparison of implant stability measurements between a resonance frequency analysis device and a modified damping capacity analysis device: an in vitro study

Purpose

A stability-measuring device that utilizes damping capacity analysis (DCA) has recently been introduced in the field of dental implantology. This study aimed to evaluate the sensitivity and reliability of this device by measuring the implant stability of ex vivo samples in comparison with a resonance frequency analysis (RFA) device.

Methods

Six implant beds were prepared in porcine ribs using 3 different drilling protocols to simulate various implant stability conditions. Thirty-six pork ribs and 216 bone-level implants measuring 10 mm in height were used. The implant beds were prepared using 1 of the following 3 drilling protocols: 10-mm drilling depth with a 3.5-mm-diameter twist drill, 5-mm drilling depth with a 4.0-mm-diameter twist drill, and 10-mm drilling depth with a 4.0-mm-diameter twist drill. The first 108 implants were external-connection implants 4.0 mm in diameter, while the other 108 implants were internal-connection implants 4.3 mm in diameter. The peak insertion torque (PIT) during implant placement, the stability values obtained with DCA and RFA devices after implant placement, and the peak removal torque (PRT) during implant removal were measured.

Results

The intraclass correlation coefficients (ICCs) of the implant stability quotient (ISQ) results obtained using the RFA device at the medial, distal, ventral, and dorsal points were 0.997, 0.994, 0.994, and 0.998, respectively. The ICCs of the implant stability test (IST) results obtained using the DCA device at the corresponding locations were 0.972, 0.975, 0.974, and 0.976, respectively. Logarithmic relationships between PIT and IST, PIT and ISQ, PRT and IST, and PRT and ISQ were observed. The mean absolute difference between the ISQ and IST values on a Bland-Altman plot was −6.76 (−25.05 to 11.53, P<0.05).

Conclusions

Within the limits of ex vivo studies, measurements made using the RFA and DCA devices were found to be correlated under a variety of stability conditions.

Influence of cortical bone and implant design in the primary stability of dental implants measured by two different devices of resonance frequency analysis: An in vitro study

Background

This study aimed to evaluate the effect of the implant design and the presence of cortical bone in the primary stability, as well as analyze the differences between the stability measurements obtained by two different resonance frequency analysis (RFA) devices.

Material and Methods

A total of 80 Klockner implants of two different models [40 Essential Cone implants (group A) and 40 Vega implants (group B)] were used. The implants were placed in two polyurethane blocks that simulated the mechanical properties of the maxillary bone. One block featured a layer of cortical bone that was absent from the other block. The primary stability of all implants was measured by insertion torque and RFA using two different devices: Penguin RFA and Osstell IDX.

Results

Primary stability was superior in the cortical bone in both torque and RFA. In the block containing cortical bone, group A implants obtained a greater insertion torque than did group B. The insertion torque was lesser in the bone lacking cortex. Regarding the ISQ of the implants, group A presented higher values in the block with cortical bone, but the values were lower in the block without cortical bone. There were no significant differences between the values obtained from the Osstell IDX and Penguin RFA.

Conclusions

The presence of cortical bone positively influences the primary stability of dental implants. The design of the implant also has a statistically significant influence on implant primary stability, although the impact depends on whether there is coronal cerclage or not. There were no statistically significant differences in the implant stability measurements obtained by two different devices.

Key words:Implant stability, resonance frequency analysis, torque, osstell, penguin, cortical.

Does the manual insertion torque of smartpegs affect the outcome of implant stability quotients (ISQ) during resonance frequency analysis (RFA)?

Background

There is disagreement about the optimal torque for tightening smartpegs for resonance frequency analysis (RFA). Subjective finger pressure during hand tightening could affect the reliability of the resulting values. The aim of the current study was therefore to assess whether or not the insertion torque of a smartpeg magnetic device influences the implant stability quotient (ISQ) value during RFA.

Methods

Thirty self-tapping screw implants (XiVE S, Dentsply Sirona Implants, Bensheim, Germany) with a diameter of 3.8 mm and a length of 11 mm were inserted in three cow ribs with a bone quality of D1. The RFA value of each implant was measured (Ostell, FA W&H Dentalwerk, Bürmoos, Austria) in two orthogonal directions (mesial and buccal) after tightening the corresponding smartpeg type 45 with a mechanically defined value of 5 Ncm (Meg Torq device, Megagen, Daegu, South Korea) (test). Additionally, 4 different examiners measured the RFA after hand tightening the smartpegs, and the results were compared (control). Insertion torque values were determined by measuring the unscrew torque of hand seated smartpegs (Tohnichi Manufacturing Co. Ltd, Tokyo, Japan).

Results

The ISQ values varied from 2 to 11 Ncm by hand tightening and from 2 to 6 Ncm by machine tightening. The comparison of hand and machine tightening of smartpegs displayed only minor differences in the mean ISQ values with low standard deviations (mesial 79.76 ± 2,11, buccal 77.98 ± 2,) and no statistical difference (mesial p = 0,343 and buccal p = 0,890).

Conclusions

Manual tightening of smartpeg transducers allows for an objective and reliable determination of ISQ values during RFA.

Correlation between Insertion Torque and Implant Stability Quotient in Tapered Implants with Knife-Edge Thread Design

Aim

To evaluate the correlation between insertion torque (IT) and implant stability quotient (ISQ) in tapered implants with knife-edge threads.

Methods

Seventy-five identical implants (Anyridge, Megagen) were inserted by using a surgical drilling unit with torque control and an integrated resonance frequency analysis module (Implantmed, W&H). IT (N/cm) and ISQ were recorded and implants were divided into three groups (n = 25) according to the IT: low (<30), medium (30 < IT < 50), and high torque (>50). ISQ difference among groups was assessed by Kruskal-Wallis test, followed by Bonferroni-corrected Mann–Whitney U-test for pairwise comparisons. The strength of the association between IT and ISQ was assessed by Spearman Rho correlation coefficient (α = 0.05).

Results

At the pairwise comparisons, a significant difference of ISQ values was demonstrated only between low torque and high torque groups. The strength of the association between IT and ISQ value was significant for both the entire sample and the medium torque group, while it was not significant in low and high torque groups.

Conclusions

For the investigated implant, ISQ and IT showed a positive correlation up to values around 50 N/cm: higher torques subject the bone-implant system to unnecessary biological and mechanical stress without additional benefits in terms of implant stability. This trial is registered with NCT03222219.

Effect of implant macrogeometry on peri-implant healing outcomes: a randomized clinical trial

OBJECTIVES

This randomized split-mouth clinical trial investigated the influence of implant macrogeometry on bone properties and peri-implant health parameters during the healing process.

MATERIAL AND METHODS

Ninety-nine implants were placed bilaterally in posterior mandibles of 23 patients that received at least four dental implant macrogeometries: standard geometry, Integra (IN) and three geometries inducing "healing chamber": Duo (D), Compact (C), and Infra (IF). Insertion torque (IT) and implant stability quotient (ISQ) were measured. Peri-implant health were monitored by visible plaque index (VPI), peri-implant inflammation (PI), and presence of calculus (CC). Data were collected during 90 days. Data were assessed for normality using the asymmetry and kurtosis coefficients followed by the Shapiro-Wilk test. A one-way ANOVA was used to investigate differences in IT and linear bone dimensions between the macrogeometry groups. The repeated measurements ANOVA test or ANOVA-R was used for analysis of ISQ, VPI, and PI. Tukey-Kramer test or Student's t test was used for comparisons between the groups or within each macrogeometry.

RESULTS

Macrogeometry did not significantly influence IT and ISQ values. The minimum ISQ was recorded after 7 days (71.95 ± 12.04, p = 0.0001). Intermediate ISQ was found after 14 days, when the ISQ reached values that are statistically identical to primary stability. The VPI showed significantly higher scores for the D (0.88 ± 1.03) and IN (0.72 ± 0.94) implants after 7 days. The PI was only influenced by the healing time significantly decreasing from 7 (1.07 ± 0.89) to 21 days (0.18 ± 0.18).

CONCLUSION

Implant macrogeometry did not influence IT nor ISQ values. The relationship between IT and SS was more evident for the Duo implant, but only in the final stage of healing process.

CLINICAL RELEVANCE

Show to the clinician that the macrogeometry and drilling protocols did not interfere in the clinical behavior of the implants during the healing process. However, the IT, primary and secondary stability, is quite dependent of the surgeon experience.