Evaluation of Implant Primary Stability Using a Standard Versus an Underpreparing Drilling Protocol with Different Measurement Methods: An In Vitro Study
Aug 2026· Osteology· Vol 6, pp. 16· 0 citations· 19 references
TL;DR
Underpreparation appears a viable technique to improve primary stability, nevertheless it might be insufficient to reach the threshold of immediate loading suitability in low density bone.
Abstract
Background/Objectives: The primary aim of this study is to evaluate the impact of two different drilling methods on the primary stability of implants inserted into polyurethane blocks simulating different bone densities. The secondary aim is to analyse the indication provided by three different methods used to assess primary stability. Methods: The study was performed on two artificial bone blocks of solid rigid polyurethane without cortical layer and one laminated one. A total of 48 implants were placed following either a Regular Primary Stability (RPS) or an Enhanced Primary Stability (EPS) protocol based on site underpreparation. Immediately after implant placement, artificial intelligence tool (AIT) indication, peak insertion torque (pIT) and Resonance Frequency Analysis (RFA) values were recorded. The values were then categorised as suitable or not suitable for single-crown immediate loading by bone density and drilling protocol. Results: EPS drilling protocol produced significantly higher primary stability values than those in all bone densities, regardless of the primary stability measurement method used, except for the implants placed in D4 and evaluated by AIT. The grouping of values shows that implants placed in D3 and D4 never reached the immediate loading threshold for a single crown. In D2, EPS and RPS protocols both reach the threshold for all implants when evaluated with pIT or RFA; when AIT is used, RPS protocol was not able to reach the single-crown threshold in 50% of cases. Conclusions: Within the limitations of this in vitro study, underpreparation appears a viable technique to improve primary stability, nevertheless it might be insufficient to reach the threshold of immediate loading suitability in low density bone. All systems used are able to report the primary stability increase obtained by underpreparation, but AIT showed the potential to detect a loss of primary stability related to torque drop during insertion. These findings require further confirmation.
Neither the choice of drilling technique nor the implant macrogeometry significantly influences insertion torque or stability levels in regions of low bone density in this randomized controlled clinical study.
Worood A Akram, S. Bede· The Journal of craniofacial...· 0 citations
The use of sequential osseodensification protocols yielded superior mechanical stability parameters, specifically in IT and RT, in synthetic (polyurethane) bone models, but improvements in ISQ were predominantly noted in the denser type III model.
Silvio Yoshiaki Okagawa, Alex Sandro Barros de Souza, P. P. D. de Carvalho et al.· International Journal of Den...· 0 citations
OBJECTIVE
To investigate the values of torque and implant stability quotient of implants with non-aggressive and «active» threads placed using standard spiral and stepped drills.
MATERIAL AND METHODS
As the experimental model was used pig's breastbone. Forty implants were divided in two groups which included 10 implants of each type according to thread design. In the first group bone site preparation was conducted with spiral drills, in the second one - using stepped drill. Peek torque values were measured with surgical motor and dynamometric key and to assess implant stability quotient was used Osstell device with Smartpeg and Multipeg pins.
RESULTS
In the first group, there was no significant difference using any type of implant. In the second group, there was a significant increase in the studied parameters during the use of implants with «active» threads with a stepped drill. Torque values increased in 1.7 times. The increase in stability quotient for both Smartpeg and Multipeg pins in average was 8% and 7% respectively. When comparing cylindrical implants with non-aggressive threads with standard drills and conical implants with «active» threads with a stepped drill, the increase of maximum torque and stability quotient was 80%, 8% and 7% respectively.
CONCLUSION
The use of cylindrical implants with non-aggressive threads when working in low density bone both when using spiral or stepped drills, is characterized by low values of torque and stability quotient. In low density bone the placement of conical implants with «active» threads using a stepped drill is effective.
B. A. Kudzaev, V. A. Badalyan, E. M. Chernovol· Stomatologiia· 0 citations
ABSTRACT Objectives Intraoperative bone assessment is critical for achieving primary implant stability, particularly at low‐density bone sites. Drilling torque value (DTV) has been proposed as an indicator of bone density and may help guide drilling preparation protocols to improve primary stability. However, the relationship between DTV and primary stability, especially histological bone parameters in biological bone, remains unclear. This study aimed to clarify the influence of different drilling protocols for primary stability at low‐density bone detected by DTVs in biological cancellous bones. Materials and Methods Cancellous bone blocks obtained from bovine ribs were used. A specially designed torque measurement drill was used to assess bone density intraoperatively. Based on the DTVs, low‐density bone sites corresponding to Misch D4 and D5 were selected. The dental Implants were placed using either a normal or undersized drilling protocol. The DTVs, insertion torque values (ITVs), and implant stability quotient (ISQ) were recorded. Histological evaluation was performed to assess the bone area fraction (BAF) around the implant. Results The ITVs were lower than the clinically recommended range for primary stability in both groups; however, they were significantly higher in the undersized group than in the normal‐sized group. The DTVs positively correlated with the ITVs in both groups. A positive correlation between DTV and ISQ was observed only in the normal‐sized group, whereas ITV was positively correlated with ISQ in both groups. Histological analysis revealed no significant difference in BAF between the two groups. BAF positively correlated with DTV, ITV, and ISQ. Conclusions DTV reflects the existing bone volume of low‐density tissue and is correlated with primary stability. Intraoperative assessment of drilling torque would facilitate the selection of appropriate drilling protocols to achieve primary stability. Bone density evaluation by measuring the DTV may provide a clinically useful method for the intraoperative evaluation at low‐density implant sites.
Yusuke Morimoto, Reiko Kobatake, K. Doi et al.· Clinical and Experimental De...· 0 citations
Introduction: Fractured implant abutment screws represent a significant mechanical complication in implant dentistry and can compromise prosthetic stability, implant longevity, and treatment outcomes. Retrieval of fractured screws is a technically demanding procedure that requires effective removal while preserving implant integrity. Several retrieval techniques have been proposed; however, evidence regarding the most efficient and reliable method remains limited. Aim: To comparatively assess the efficacy of different methods for retrieval of fractured implant abutment screws in an in vitro setting. Materials and Methods: A total of 108 implant specimens embedded in acrylic blocks were included in this in vitro experimental study and equally divided into three groups (n=36): Group I—Claw-Type Retrieval Kit, Group II—Reverse Drilling Retrieval Kit, and Group III—Conventional Hand Instrumentation. Fracture morphologies (ASF-1, ASF-2, and ASF-3) were equally distributed among all groups. Outcome variables evaluated included retrieval success rate, number of attempts required, retrieval time, and implant thread integrity following retrieval. Data were statistically analyzed using SPSS version 21.0. Chi-square test, one-way ANOVA, and Tukey post hoc analysis were applied, with p<0.05 considered statistically significant. Results: Overall retrieval success was achieved in 72.2% of specimens. Reverse Drilling and Conventional Instrumentation demonstrated higher retrieval success rates (75%) compared with Claw-Type retrieval (66.7%), although differences were not statistically significant. Reverse Drilling showed significantly greater procedural efficiency with a higher rate of single-attempt retrieval and the shortest mean retrieval time (10.31 ± 3.42 minutes) (p<0.001). No significant differences were observed regarding implant thread damage among the groups. Conclusion: Reverse Drilling demonstrated superior procedural efficiency with fewer retrieval attempts and shorter retrieval time while maintaining implant thread integrity, suggesting that it may represent a reliable and clinically effective technique for fractured implant abutment screw retrieval.
Shitij Srivastava, Akshat Srivastava, A. Shekhar et al.· Genetics and Molecular Resea...· 0 citations
INTRODUCTION
Mini-implant placement has become a routine method for providing anchorage in orthodontic treatment. The stability of these implants is influenced by several factors, including implant design, bone quality, site preparation, insertion angle, and loading protocol. Among these, implant and bone quality are largely unmodifiable. Resonance Frequency Analysis (RFA) is widely used to assess implant stability. This ex vivo study aimed to evaluate the impact of immediate loading on the stability of orthodontic mini-implants using RFA.
MATERIALS AND METHODS
This prospective animal study assessed the primary stability of 72 self-drilling stainless steel mini-implants of three lengths (1.3 mm × 6 mm, 1.3 mm × 8 mm, and 1.3 mm × 10 mm). A 2 N load was applied using nickel-titanium coil springs. Stability was measured by RFA immediately after force application (T0) and after 5 weeks (T1).
RESULTS
Initial stability was comparable across all implant lengths. After 5 weeks of loading, all groups demonstrated a reduction in stability. The 6 mm implants showed a significantly greater loss of stability (5.31 ± 4.89) compared to the 8 mm (2.36 ± 4.08) and 10 mm (2.39 ± 1.64) implants. All lengths exhibited statistically significant stability loss post-loading (6 mm, p = 0.001; 8 mm, p = 0.009; 10 mm, p = 0.001).
CONCLUSION
Variations in implant length did not significantly affect immediate stability following loading. However, over time, 6 mm implants experienced greater stability loss compared to 8 mm and 10 mm implants. Despite this, shorter implants exhibited slightly higher initial stability under load.
T. Chang, K. Pradeep, C. V. Padma Priya et al.· Orthodontics & craniofacial...· 0 citations
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