Effects of Different Undersizing Site Preparations on Implant Stability

Concerns have been expressed about the possibility of high insertion torque (IT) causing necrosis, impaired osseointegration, and crestal bone loss over time. The present study investigated the relationship between primary stability and implant success, including early and late maintenance of crestal bone levels. Implants were placed in patients at three study centers. Every effort was made to achieve the highest possible primary stability, which was measured with IT and implant stability quotient (ISQ). The IT and ISQ at insertion and reopening (3 to 4 months), as well as bone levels at several points in time, were recorded. The correlations between IT, ISQ, and immediate and 3-year crestal bone loss were investigated through linear regression analyses. Average IT was 76.1 ± 20.8 Ncm, while the average ISQ score was 80.4 ± 8.4. The implant success rate at 36 months was 98.6%. The crestal bone loss around most implants (41.0%) ranged from 0.05 to 0.5 mm. None of the osseointegrated implants had crestal bone loss greater than 2.5 mm. The linear regression analysis showed no correlation among early or 3-year crestal bone loss and IT, ISQ at surgery, and ISQ at reopening. The implants studied avoided any negative effects deriving from the high IT values (≥ 50 Ncm) applied during 3 years of follow-up.

This study was designed to evaluate the effects of four different surgical techniques on the primary stability of short implants in two sizes (4-mm and 6-mm length) through resonance frequency analysis and insertion torque measurement in vitro. Forty implant site preparations and implant insertions were performed in pig ribs. Guided surgery, bone condensing, conventional drilling, and undersized preparation surgical techniques were used five times in each bone block to prepare 4-mm/6-mm-length implant beds. The maximum insertion torque and implant stability quotient (ISQ) values were recorded for each implant. Both the ISQ and torque differed significantly for various surgical techniques (P = .009 and P < .001). The conventional technique had higher ISQ (79.00), whereas the condenser technique had higher torque (48.00 Ncm) than did the other techniques. The mean torque was significantly higher in all surgical techniques other than the guided surgery group regardless of implant length (P < .01 for all). Implant lengths were not significantly different in terms of ISQ and torque in all surgical techniques. There are significant correlations between the implant bed preparation technique and primary implant stability when using short implants. Conventional surgery and the bone condensing technique are favorable alternatives with higher primary stability and torque values in short implants.

Background/Objectives: It remains unclear which drilling strategy is most effective for maximizing mechanical stability in low-density bone and whether high insertion torque is determinative. The aim of this in vitro study was to compare the primary stability of implants placed using different drilling protocols-conventional (CV), undersized (US), and osseodensification (OD). Three osseodensification systems-Versah burs (V), Bone Reamer Drills (WF), and Master Conical Densifiers (DSP)-were also compared. Methods: A set of 11 blocks was used for the drilling protocol comparison (CV, US, OD) and a separate set of 11 blocks was used for the osseodensification system comparison (V, WF, DSP). External-hexagon implants were inserted epicrestally. Insertion torque was measured using a torque meter, and implant stability quotients (ISQs) were assessed through resonance frequency analysis. Results: ISQ for OD was significantly higher than that for CV but statistically similar to that for US, whereas insertion torque for OD was significantly higher than that for both US and CV. A weak correlation was found between variables for CV and US, and a moderate one was observed for OD. Both WF and DSP showed significantly higher ISQ values than V. Insertion torque for DSP was significantly higher than that for both WF and V. A moderate correlation was found between variables for DSP and V, and a weak one for WF. Conclusions: In this invitro study, the OD protocol performed better than CV in terms of ISQ and better than both CV and US in terms of insertion torque. WF and DSP outperformed V in ISQ, whereas DSP yielded the highest insertion torque. Weak-to-moderate correlations between variables in both analyses indicated that higher insertion torque did not necessarily translate into greater stability.

ObjectivesResonance frequency analysis (RFA) is used to monitor implant stability. Its output, the Implant Stability Quotient (ISQ), supposedly correlates with insertion torque, a common measurement of primary stability. However, the reliability of RFA in condensed bone remains unclear.Material and methodsIn this human cadaver study in edentulous jaws and fresh extraction sockets, implants were inserted using a split‐mouth approach into condensed or untreated bone. Mean ISQ, peak insertion torque, and pre‐ and postoperative bone volume fractions (BV/TV) were assessed.ResultsIn edentulous jaws, insertion torque and ISQ correlated both in untreated (r = 0.63, p = 0.02) and in condensed (r = 0.82, p < 0.01) bone. In extraction sockets, insertion torque and ISQ only correlated in untreated (r = 0.78, p < 0.01), but not in condensed bone (r = 0.15, p = 0.58). In all edentulous jaws, preoperative BV/TV correlated with insertion torque (r = 0.90, p < 0.0001), ISQ (r = 0.64, p < 0.001), and changes in BV/TV (r = –0.71, p < 0.01). In all extraction sockets, preoperative BV/TV did not correlate with either insertion torque (r = 0.33, p = 0.15), ISQ (r = 0.38, p = 0.09), or changes in BV/TV (r = –0.41, p = 0.09). Joint analysis identified preoperative BV/TV as a predictor of postoperative BV/TV (p < 0.001), insertion torque (p < 0.001), and ISQ (p < 0.001).ConclusionsRFA is feasible for monitoring stability after late implant placement into condensed bone, but not after immediate placement into condensed fresh extraction sites.

The aim of the study was to investigate the effect of parathyroid hormone (PTH) on primary stability of dental implants in a bone-reduced model. Ten female New Zealand white rabbits underwent ovariectomy and were administered glucocorticoid to induce osteoporosis. One group was administered PTH intermittently by subcutaneous injection for 4 weeks (PTH-group) and the other group was given injections of saline for 4 weeks (Osteoporosis; OP-group). After the administration period, implants were inserted into the distal femoral epiphyses of each animal. At implant placement, insertion torque (IT) and implant stability quotient (ISQ) were measured. Histological examination revealed newly formed trabecular bone around the implant socket in the PTH-group but not in the OP-group. The trabecular bone structures in the PTH-group appeared thicker than those in the OP-group. In the PTH-group, the mean IT value was significantly greater than that in the OP-group (29.8 ± 6.2 Ncm and 10.0 ± 2.1 Ncm, respectively; P < 0.05). The ISQ value in the PTH-group was significantly higher than that in the OP-group (74.7 ± 11.2 and 55.9 ± 13.5, respectively; P < 0.05). Intermittent PTH administration could be an effective treatment for achieving favorable primary stability of dental implants in patients with osteoporosis. (J Oral Sci 58, 241-246, 2016).

Implant primary stability, which depends mainly on the amount and quality of bone, is important for implant survival. Socket preservation aims to reduce bone volumetric changes after tooth extraction. This animal study aims to examine whether preserving a ridge by using xenograft impairs the primary stability of the implant. Eighteen artificial bone defects were prepared in 4 sheep (5- and 8-mm length). Defects were randomly grafted with xenografts: Bio-Oss (BO), Bio-Active bone (BB), or left for natural healing (control). After 8 weeks, bone biopsy was harvested and dental implants installed. During installation, peak insertion torque (IT) was measured by hand ratchet, and primary stability by the Osstell method. Histomorphometric analysis showed a higher percentage of new bone formation in the naturally healed defects compared to sites with xenograft (control: 68.66 ± 4.5%, BB: 48.75 ± 4.34%, BO: 50.33 ± 4.0%). Connective tissue portion was higher in the BO and BB groups compared to control (44.25 ± 2.98%, 41 ± 6%, and 31.33 ± 4.5%, P < .05, respectively). Residual grafting material was similar in BO and BB (7 ± 2.44%, 8.66 ± 2.1%, respectively). Mean IT and implant stability quotient (ISQ) values were not statistically different among the groups. A positive correlation was found between IT and ISQ (r = 0.65, P = 0). In conclusion, previously grafted defects with xenograft did not influence primary stability and implant insertion torque in delayed implant placement. These results may be attributed to a relatively high bone fill of the defect (∼50%) 2 months after grafting.

Background: The long-term success of dental implants largely depends on achieving primary stability, previously described as crucial to obtaining osseointegration and immediate loading protocol requirements. Implant thread depths seem to be one of the key factors influencing primary stability, particularly in low-density bone. Insertion torque (IT) and resonance frequency analysis (RFA) are considered the most reliable tests to assess primary stability. The aim of this work was to evaluate how different thread depths of commercially available dental implants affect primary stability in low-density D3 bone. Materials and Methods: An in vitro study was carried out between February 2024 and March 2024. Twenty-four dental implants were divided into four groups (six implants each) according to their thread depths (Group A: 4 mm, Group B: 4.5 mm, Group C: 5 mm, Group D: 5.5 mm) and were inserted in D3-type artificial bone blocks. The main outcome variables were the IT and the Implant Stability Quotient (ISQ) measured in four different areas of the implant (buccal, lingual, mesial, and distal) with an Osstel® ISQ reader. Descriptive and inferential analyses of the data were performed, and the significance value was set at 5%. Results: A total of 24 implants were analyzed. The highest IT values were obtained in Group D, with a mean of 54.03 Ncm (standard deviation (SD) = 8.99), while the lowest measurements were observed in Group A (mean = 25.12; SD: 2.96 N.cm). The mean ISQ values were consistently higher in Group D for each analyzed area, with a mean of 70.13 N.cm (SD = 1.12). Conclusions: Taking into consideration the limitations of this in vitro study, greater thread depths seem to increase the primary stability of dental implants placed in soft bone. Furthermore, a positive correlation was observed between all IT and ISQ values, regardless of the thread depth.

There are several types of primary and secondary stability measuring methods, but there are no calculating methods to determine direct primary stability. The aim of this work is to make a calculation method for primary stability. The out coming result of the calculation should be the same form and unit as available in the clinical and used RFA (Resonance Frequency Analysis) method, especially the ISQ (Implant Stability Quotient). Dental implant analog screws were inserted in bone modelling standard PUR (Polyurethane) solid foam blocks, and the insertion torque and the micromotion was monitored. The ISQ values of the inserted screws were measured also. On the basis of results, the characteristic equation was determined, which showed an excellent correlation (r = 0.96) between the micro mobility and ISQ. To simulate the micro mobility of an inserted screw with FEA (Finite Element Analysis) in any case of the change the bone material properties is not difficult instead of in vitro and in vivo examinations. Using the simulation results and the characteristic equation the clinically used ISQ value could be determinable. Thanks to this simple method, it is easy to monitor virtually the stability change in any lesion of bone structure. As a result of the conducted measurements and simulations, it can be concluded that the ISQ value, which represent the implant primary stability, can be calculated via FEA. With this simulation method, it is possible to predict and monitor pre-clinically the primary stability of dental implants with new geometries.

BackgroundThe purpose of this study was to compare a parallel wall design implant to a tapered apex design implant when placed in the posterior maxilla using two different surgical protocols.MethodsTwenty-seven patients (30 implants) were divided into three groups. All implants were 4 mm wide in diameter and 8 mm long.Group A received 10 tapered implants (OSPTX) (Astra Tech OsseoSpeed TX™) using the soft bone surgical protocol (TXSoft).Group B received 10 tapered implants (OSPTX) (AstraTech OsseoSpeedTX™) using the standard surgical protocol (TXStd).Group C received 10 parallel wall implants (OSP) (AstraTech OsseoSpeed™) using the standard surgical protocol (OStd).All implants were placed in the posterior maxilla in areas with a minimum of 8-mm crestal bone height.Resonance frequency measurements (implant stability quotient (ISQ)) and torque values were recorded to determine initial implant stability. All implants were uncovered 6 weeks after placement and restored with a functionally loaded resin provisional screw-retained crown. Resonance frequency measurements were recorded at the time of implant placement, at 6 weeks and 6 and 12 months. Twelve months after implant placement, the stability of the implants was recorded and the final restorations were placed using custom CAD/CAM fabricated abutments and cement-retained PFM DSIGN porcelain crowns. After implant restoration, bone levels were measured at 6 and 12 months with standardized radiographs.ResultsRadiographic mean bone loss was less than 0.5 mm in all groups, with no statistically significant differences between the groups. Implant survival rate at 1 year was 93.3%, with 2/30 implants failing to integrate prior to functional loading at 6 weeks. No statistically significant difference was found between ISQ measurements between the three groups at all time intervals measured. Strong positive correlations were found between overall bone loss at 6 months and insertion torque at time of placement. A very weak correlation was found between insertion torque and ISQ values at time of implant placement.ConclusionsSurvival and stability of OSPTX and OSP implants is comparable. Osteotomy preparation by either standard or soft bone surgical protocol presented no significant effect on implant survival and stability for the specific implant designs.

BackgroundTo verify the influence of macrogeometry with healing chambers on the osseointegration of dental implants by analyzing implant stability quotient (ISQ) and evaluate the correlation between insertion torque and ISQ insertion with different macrogeometries.MethodsIn total, 26 implants were installed in the posterior mandible of eight patients with sufficient bone height for the installation of implants measuring 3.5 mm in diameter and 9.0 mm in length. The implants were categorized according to two types of macrogeometry: a test group (GT) with 13 conical implants with healing chambers and a control group (GC) with 13 conical implants with conventional threads. To insert the implants, a bone drilling protocol was used up to a diameter of 3 mm with the last helical bur. The insertion torque of the implants was evaluated, followed by the measurement of ISQ at 0 (T-0), 7 (T-7), 14 (T-14), 21 (T-21), 28 (T-28), and 42 (T-42) days.ResultsThe mean insertion torque was 43 Ncm in both groups, without a significant difference. Moreover, no significant difference in the ISQ values was found between the groups at different time points (p > 0.05), except at T-7 (GT = 69.87±1.89 and GC = 66.48±4.49; p = 0.01). Although there was no significant difference, ISQ median values were higher in the GT group than GC group at 28 days (GT = 67.98 and GC = 63.46; p = 0.05) and 42 days (GT = 66.12 and GC = 60.33; p = 0.09). No correlation was found between the insertion torque and ISQ insertion (p > 0.05).ConclusionFurthermore, implants with a 3.5 mm diameter macrogeometry, with or without healing chambers, inserted with a drilling protocol up to 3 mm in diameter of the last helical bur, led to a similar secondary stability, with no difference in ISQ values. Although, implants with healing chamber demonstrates ascending values in the graph of ISQ, having a trend of faster osseointegration than implants without healing chambers. Both macrogeometries provide a similar primary stability to implants.Trial registrationThis study was registered retrospectively in ReBec (brazilian registry of clinical trials) under the number RBR-96n5×69, on the date of 19/06/2023.

The objective of this study was to compare the osseodensification drilling technique used with Densah implant drills (Versah) to standard drilling by evaluating their contribution to primary implant stability. A total of 21 mandibles dissected from cadavers were selected. Axiom drills (Anthogyr) were used for 29 standard drilling (SD) protocols in the control group. In the test group, the Densah profile drills were used to perform 29 osteotomies (OD). Implant placement was performed for 58 of these procedures. The insertion torque (IT) and implant stability quotient (ISQ) were recorded. High-resolution CBCT allowed for a postoperative analysis of the peri-drilling bone tissue. For 16 osteotomies without implant placement, Mann-Whitney U test was used for comparison of IT and ISQ values between groups. Spearman rank correlation coefficient was used between IT and ISQ values. The significance level was α = .05. The IT values for OD and SD were, respectively, 34.9 Ncm ± 19.1 and 23.6 Ncm ± 9.8. The IT was significantly higher in the OD group compared to the SD group (P = .036). A moderate positive correlation (ρ = 0.527) between IT and ISQ was observed, as well as a significant increase (P = .026) in bone density. There was a significant increase in IT and bone density following an osseodensification procedure compared to standard drilling.

Background and objective A new type of implant with aggressive threads, called the BLX implant, has been designed to provide greater adhesion to the bone. This study investigates the early implant stability between aggressive (BLX) and non-aggressive (BL) thread implants using Implant Stability Quotient (ISQ) values and Implant stability test (IST) values.) Method BLX and BL implants were placed by block randomization (12 BLX implants, 10 BL implants) following the manufacturer protocol. The insertion torque was recorded. The Implant Stability Quotient (ISQ) values were measured immediately after placement and 6 weeks after implant placement while the Implant stability test (IST) values were measured immediately after placement and continuously measured at the second day,1,2,3,4,5 and 6 weeks after implant placement. Result The ISQ immediately placement and week 6 and IST immediately placement and second day,1,2,3,4,5, and 6 weeks after implant placement were no significant differences. For aggressive thread implants (BLX), ISQ immediately placement and week 6 were no significant differences. But IST decreased at week 2. After that, IST gradually increased and shows a significantly different at week 6 follow-up. For non-aggressive thread implants (BL), ISQ and IST There were no significant differences. In addition, ISQ and IST were statistically significantly related. Conclusion The thread of the implant does not affect the stability of the implant. and ISQ and IST were significantly correlated.

Objectives:Implant primary stability is one of the important factors in achieving implant success. The osteotome technique may improve primary stability in patients with poor bone quality. The aim of this study was to compare implant stability using two different techniques namely osteotome versus conventional drilling in the posterior maxilla.Materials and Methods:In this controlled randomized clinical trial, 54 dental implants were placed in 32 patients; 29 implants were placed in the osteotome group and 25 in the conventional drilling group. Implant stability was assessed at four time intervals namely at baseline, one, two and three months after implant placement using resonance frequency analysis (RFA).Results:Primary stability based on implant stability quotient (ISQ) units was 71.4±7 for the osteotome group and 67.4±10 for the control group. There was no statistically significant difference between the two groups in implant stability at any of the measurement times. In each group, changes in implant stability from baseline to one month and also from two months to three months post-operatively were not significant but from one month to two months after implant placement, implant stability showed a significant increase in both groups.Conclusion:The results of this study revealed that in both techniques, good implant stability was achieved and osteotome technique did not have any advantage compared to conventional drilling in this regard.

To determine the significance of primary stability, as measured by insertion torque (IT) and/or implant stability quotient (ISQ), in achieving osseointegration of nonimmediately loaded implants. Three electronic databases were searched. Studies were included if they measured IT and/ or ISQ at time of placement and reported survival for up to 1 year. For studies where at least one implant failed, a random effects meta-analysis was carried out for the odds of survival. In total, 3,431 publications were screened, and 79 were accepted for analysis. These included 28 RCTs, 12 CCTs, 10 cohort studies, and 29 case series. Overall, 21 studies provided individual implant data for a total of 1,413 implants, and 7 studies were included for meta-analysis. A total of 264 implants were placed with ISQ < 60 and 249 with IT < 35. Survival of implants placed with ISQ < 60 and IT < 35 were 97.7% and 95.2%, respectively. Meta-analysis found no evidence that an ISQ ≥ 60 was less likely to fail compared to ISQ < 60 (OR 0.54, 95% CI 0.17 to 1.75, P = .31), or that an IT ≥ 35 resulted in higher odds of failure compared to IT < 35 (OR 0.82, 95% CI 0.13 to 5.40, P = .84). This study found no evidence to support that an IT ≥ 35 or ISQ ≥ 60 for nonimmediately loaded implants results in higher survival than those below these values.

"Relationship between insertion torque and ISQ of 600 implants placed in soft bone with different surgical techniques." in vitro study.