Insertion Torque Research Articles

Clinical Evaluation of Stability of Short Deep Threaded Dental Implant During Early Healing Period: A Prospective Controlled Clinical Trial

Objectives: To assess the initial stability of short, deep-threaded dental implants placed in the posterior mandible and to determine the influence of deep-thread design on implant stability during early healing. Methods: Twenty short, deep-threaded implants were placed in the posterior mandibular region of ten patients. Insertion torque value (ITV) was recorded at implant placement. Implant stability quotient (ISQ) was measured immediately post-surgery and at weeks 2, 3, 4, and 5. Results: No significant difference in ITV was observed between short and standard implants. ISQ values did not significantly differ between implant types across the evaluation period (F = 1.17, p = 0.3). Conclusion; Short, deep-threaded implants demonstrate comparable primary stability to standard implants in the posterior mandible. These findings support their use as a viable treatment option for patients with advanced alveolar ridge resorption

Full-arch prostheses supported by implants with different macrostructures: A multicenter randomized controlled trial.

This study evaluates the clinical performance of implants with hydrophilic surface and two different macrostructures: cylindrical with perforating triangular threads (CT) and cylindrical-tapered with the association of square and condensing and perforating triangular threads (TST). This was a multicenter split-mouth, simple-blinded, randomized, and controlled trial. Thirty patients with edentulous mandible received two CT and two TST implants. Primary stability was determined by insertion torque and resonance frequency analysis (RFA). Implants were loaded with full fixed-arch prostheses within 24 h after insertion. Clinical parameters (visible plaque index, marginal bleeding index; bleeding on probing; probing depth; and clinical attachment level) and the RFA were assessed at 2, 6, 12, and 24 months after implant loading. Marginal bone level changes were measured by comparison of standardized radiographs taken on the day of implant placement and 6, 12, and 24 months thereafter. Twenty-eight patients completed the 2-year follow-up. The survival rates were 99.16% for CT implants and 100% for TST implants. One CT implant was lost until the 2 months follow-up. No significant differences were found between the two implant types for marginal bone level changes (CT 0.34 [0.24; 0.55 mm]; 0.33 [0.18; 0.55 mm]; 0.41 [0.12; 0.7 mm] vs TST 0.36 [0.14; 0.74 mm]; 0.33 [0.23; 0.63 mm]; 0.30 [0.20; 0.64 mm] at 6, 12, and 24 months, respectively) and other clinical parameters. The macrostructure of the implants had no influence on survival rate, primary and secondary stability, marginal bone level changes, and peri-implant clinical parameters outcomes. Both implants can be predictably used for immediate loading of full-arch mandibular prostheses.

The relationship between the secondary implant stability quotient and oxidized implant-related factors: A retrospective study

ObjectiveThe present retrospective study aimed to determine the relationship between the secondary implant stability quotient and different parameters related to an oxidized implant. MethodsA total of 135 patients (305 oxidized implants) were included. Implant-related factors (length, diameter, surgical and loading protocols, grafting, insertion torque, and primary stability) were used for comparisons and linear regression analyses, using secondary ISQ as the dependent variable. ResultsAt the patient level, the mean time from implantation to secondary ISQ registration was 20.3 ± 29 weeks, and the mean secondary ISQ was 77.30 ± 7.22. The ISQ did not reveal significant differences regarding implant lengths, loading protocol, and simultaneous grafting. In contrast, platform diameters (3.5, 4.3, and 5.0), surgical protocols (one stage versus two stages), insertion torque (<35 Ncm versus >35 Ncm), and primary stability (achieved versus not achieved) all revealed significant secondary ISQ differences. Nevertheless, the regression analysis demonstrated that the platform diameter was the only variable significantly and positively predicted the secondary ISQ. Similar findings were found with the implant level analysis. ConclusionsAmong different implant- and protocol-related parameters, the platform diameter of the oxidized implant appears to be the only significant predictor of high secondary ISQ values at the time of superstructure connection.

Implant Stability After Graftless Motor-Driven Crestal Sinus Elevation: A Cohort Study.

Graftless motor-driven crestal sinus elevation may be a preferable alternative to conventional methods due to the reduction of postsurgical complications and lower cost. This prospective cohort study evaluated the stability of implants installed using this technique. Twenty-nine Straumann BLT (bone level tapered) implants in 29 patients were included in the sample. Average implant stability quotients (ISQ) were measured immediately after surgery (mean: 73.5 ± 9.2) and after a period of healing (mean: 77.1 ± 4.5) using resonance frequency analysis (RFA). There was a significant increase in implant stability after healing (P = .035). The healing duration did not significantly influence how implant stability increased (P =.373). The mean ISQ after healing was significantly higher than the clinically acceptable stability value of 65 ISQ (P < .001). Implant length and width were not significantly correlated with ISQ increase (P = .764 and P = .085, respectively). In addition, there were no significant differences in average ISQ values measured immediately postsurgery (at baseline) or after healing between implants with and without registered perforations during surgery (P = .118 and P = .366, respectively). The posthealing stability of 4 implants that did not achieve primary stability was not significantly less stable after the healing period than those that had achieved primary stability (P = .086). Moreover, the level of insertion torque significantly impacted implant stability immediately postsurgery (P < .001), but the ISQ values measured after healing were not significantly different based on the initial insertion torque values (P = .131). This study suggests that implants installed using graftless motor-driven crestal sinus elevation may achieve clinically acceptable stability as measured by RFA.

Analysis of osseointegration of implants with macrogeometries with healing chambers: a randomized clinical trial

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 reliability of insertion torque as an indicator for primary stability in immediate dental implant: A prospective clinical study

Background: The primary stability of the dental implant is a crucial factor determining the ability to initiate temporary implant-supported prosthesis and for subsequent successful osseointegration, especially in the maxillary non-molar sites. This study assessed the reliability of the insertion torque of dental implants by relating it to the implant stability quotient values measured by the Osstell device. Material and methods: This study included healthy, non-smoker patients with no history of diabetes or other metabolic, or debilitating diseases that may affect bone healing, having non-restorable fractured teeth and retained roots in the maxillary non-molar sites. Primary dental implant stability was evaluated using a torque ratchet from the dental implant kit and ISQ values generated from the Osstell device. Results: Twenty patients (13 female and 7 male) with an age range of 25-65 years received twenty immediate dental implants. The insertion torque value ranged from 15 to 50 N/cm with a mean of 28 N/cm. At the same time, the ISQ values ranged between 50 and 80 ISQ values, with a mean of 63 ISQ values. The results showed a statistically significant positive correlation between the insertion torque of the dental implant measured by torque rachet and ISQ values checked with Osstell. Conclusion: The insertion torque can be used as a reliable method to estimate the primary stability of the immediately inserted dental implants in the maxillary non-molar sites comparable to the Osstell device ISQ values. In addition, torque ratchet is readily available in the dental implant kit at no additional cost, making it a valuable choice over the Osstell device.

Clinical Performance of Extra-Short (≤5.5 mm) Compared to Longer Implants Splinted under the Same Prosthesis: A Randomized Clinical Trial.

Objective: This randomized controlled split-mouth trial compared the performance of 5.5 mm length implants (test group; TG) splinted within the same fixed prosthesis as longer implants (≥6.5 mm; control group; CG) in posterior regions. Methods: The primary hypothesis was that implant length does not affect marginal bone loss (MBL) one year post-implantation, while the secondary hypotheses included implant survival, peri-implant clinical variables, and prosthetic complications. Fifteen patients (eight males, seven females) with a mean age of 67 ± 9 years were included. Results: No significant difference in the implant position between groups (p = 0.808) was observed. Implant diameters ranged from 3.00 to 4.25 mm, and the most common bone type was type I (67%). Bone density (p = 0.574) and implant insertion torque (p = 0.888) were similar between groups. Mesial MBL (mean: -0.1; range: -1.19 to 0.24 for TG, and -0.03; -1.75 to 0.45 for CG; p = 0.955) and distal MBL (mean: -0.05; range: -1.41 to 0.27 for TG, and 0.08; -1.45 to 0.72 for CG; p = 0.118) did not show statistical differences. There were no implant failures or technical complications. Conclusions: These findings suggest that 5.5 mm length implants could be a viable option for use in posterior regions, providing similar clinical outcomes to longer implants one year post-implantation.

Impact of Diamond-like Carbon Films on Reverse Torque: Superior Performance in Implant Abutments with Internal Conical Connections

The loosening or fracture of the prosthetic abutment screw is the most frequently reported complication in implant dentistry. Thin diamond-like carbon (DLC) films offer a low friction coefficient and high wear resistance, functioning as a solid lubricant to prevent the weakening of the implant–abutment system. This study evaluated the effects of DLC nanofilms on the reverse torque of prosthetic abutments after simulated chewing. Abutments with 8° and 11° taper connections, with and without DLC or silver-doped DLC coatings, were tested. The films were deposited through the plasma enhanced chemical vapor deposition process. After two million cycles of mechanical loading, reverse torque was measured. Analyses with scanning electron microscopy were conducted on three samples of each group before and after mechanical cycling to verify the adaptation of the abutments. Tribology, Raman and energy-dispersive spectroscopy analyses were performed. All groups showed a reduction in insertion torque, except the DLC-coated 8° abutments, which demonstrated increased reverse torque. The 11° taper groups experienced the most torque loss. The nanofilm had no significant effect on maintaining insertion torque, except for the DLC8 group, which showed improved performance.

The Effect of Increasing Thread Depth on the Initial Stability of Dental Implants: An In Vitro Study

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.

A Comparison of Different Implant Site Preparation Techniques in Low-Density Bone: An Ex-Vivo Study.

Osseointegration is considered a prerequisite for the long-term success of dental implants, and many researchers have considered the stability of the implant when placed in the bone. Many techniques include undersized drilling, densifying burs, magnetic mallets, and expanders. These methods have led to higher initial insertion torque values. The present study aims to evaluate the effectiveness of expanders, densifying burs, and magnetic mallet methods for preparing the implant site in low-density bone and compare them in terms of achieving good initial implant stability. The present study was conducted in an ex vivo animal model using bovine rib bones. This study was performed on 20 bovine ribs; each rib had four implant site preparations divided into four groups according to the drilling method: a control group of the conventional technique (n=20), the expanders group (n=20), the densification burs group (n=20), and the magnetic mallet group (n=20). The measured values were Primary Insertion Torque and Implant Stability Quotient (ISQ). The highest average insertion torque was in the magnetic Mallet group, where the average was 43.75 N/cm2, followed by the burs group, where the average was 43.00 N/cm2, then the expanders group with an average of 32.80 N/cm2, then the conventional preparation group with 19.30 N/cm2as the lowest average among the study groups. The highest ISQ mean was in the burs group, where the mean was 80.30, followed by the magnetic Mallet group, where the mean was 80.20, then the expanders group with a mean of 68.90, then the conventional preparation group with 50.10 as the lowest mean among the study groups. Within the limitation of this study, we conclude that all methods used were better than conventional preparation in both ISQ and insertion torque, with the magnetic mallet group outperforming the insertion torque and the Densah burs outperforming the ISQ.

Unlocking implant success: the impact of surgical techniques on primary stability in the posterior maxilla.

The study conducted by Olmedo-Gaya et al. aimed to investigate the effects of various surgical techniques on the initial stability of implants placed in the posterior maxilla through a randomized controlled clinical trial. The study compared insertion torque (IT) and implant stability quotients (ISQ) among implants placed using under preparation, expanders, and standard surgical instrumentation. The study enrolled 108 patients, each receiving one implant in the posterior maxilla region. Patients were distributed into three groups: group 1 (n = 36) with the under preparation technique, group 2 (n = 36) using the expander technique, and group 3 (n = 36) with conventional drilling. IT was measured using a torque indicator, while ISQ was recorded through resonance frequency analysis immediately post-surgery. The ISQ values were analyzed in relation to the patient's bone quality, categorized into types II, III, and IV. ISQ values varied significantly with bone quality, being highest in type II (76.65) and type III (73.60), and lowest in type IV (67.34) bone, with a significant difference (p < 0.0001). The conventional drilling technique yielded lower ISQ values (69.31) compared to under preparation (74.29) and expander techniques (73.99), with statistical significance (p = 0.008 and p = 0.005, respectively). Surgical technique significantly influences primary stability in low-quality bone. Conventional drilling results in lower ISQ values, suggesting that alternative techniques such as under preparation or expanders should be used in low-quality bone to achieve better primary stability. For implants in low-quality bone, replacing the conventional drilling technique with under preparation or expander techniques can enhance primary stability.

Immediate Implants in Fibulas: Does the Implant to Fibula Osteotomy Distance Impact Early Implant Failure?

BackgroundWhen placing dental implants in the free fibula flap, the osteotomy cut edge poses a unique challenge in that an optimal distance has not yet been established. PurposeThe study aimed to measure the association between implant-to-fibula osteotomy edge distance and early implant failure in patients who received free fibula flap reconstruction with immediate implants. Study DesignA retrospective cohort study was designed and implemented. The study population was composed of patients who underwent free fibula flap transfer with immediate dental implant placement for the treatment of benign or malignant conditions of the head and neck from 2015 to 2022 at John Peter Smith Hospital. Subjects were excluded if the implant was in the middle of the free flap bordered by adjacent implants, was >10mm from the osteotomy edge, or had insertional torque values of ≤30 Ncm. Predictor VariablePrimary predictor variable was the implant distance in millimeters from the fibula osteotomy edge. Outcome VariablePrimary outcome variable was early implant failure, defined as implant exfoliation noted by the patient or failure due to implant movement or pain necessitating explantation within 6 months of placement. CovariatesThe covariates were age, sex, diabetes diagnosis, American Society of Anesthesiologists classification, smoking status, history of head and neck radiation, pathology treated, and if postoperative radiation treatment was received. AnalysesA generalized estimating equations (GEE) model was used to assess the relation between the primary predictor and outcome. A p-value of <0.05 was considered statistically significant. ResultsThe sample was composed of 48 subjects who had 130 implants placed, with early failures occurring in 5 implants (3.9%) in 3 subjects. The mean age of the sample was 49 years (SD 20) and 29 (60%) were male. The mean implant distances for early failures and non-failures were 3.5 mm (SD 1.04) and 4.3 mm (SD 1.5), respectively. There was a statistically significant relation between implant distance and early implant failure (P = .005, OR 0.6, 95% CI 0.39 to 0.85). ConclusionsThis study found that shorter distances between the implant and the edge of the fibula osteotomy are associated with early implant failure.

Clinical and experimental justification of the methods of treatment for distal occlusion (literature review)

One of the main issues in the treatment of patients with various dental and jaw abnormalities is ensuring the stability of the position of the supporting teeth, which is a necessary condition for the movement of teeth during orthodontic treatment. 45 to 75 % of the population need orthodontic correction, distal occlusion is found in 10–25 % of the population. The use of mini dental implants is the most effective method of providing the stability of the support. The stability of a mini dental implant during orthodontic treatment depends on many factors such as implant type, dimensions, surface characteristics, insertion angle, insertion torque, amount of applied orthodontic force, topography, and soft tissue characteristics. The rate of treatment failure remains quite high, so treatment methods need further study and improvement. The provision of stable support in teeth shifting in patients with distal occlusion with an enlarged upper jaw and of the possibility of molar distalization in this category of patients remains a particularly important issue.

Nondestructive acoustic modal analysis for assessing bone screw stability: An ex vivo animal study.

Conventional insertion torque and pull-out tests are destructive and unsuitable for clinical bone screw fixation. This study evaluates screw stability using acoustic modal analysis (AMA) and Periotest compared to traditional methods in an ex vivo animal model. Titanium self-tapping screws (STS) and nonself-tapping screws (N-STS) were implanted in the proximal tibia of 12 rabbits. Four testing methods were used to assess screw stability: peak insertion torque (PIT) during implantation, AMA for natural frequency (NF), Periotest for Periotest value (PTV), and pull-out test for peak pullout force (PPF). Euthanization was performed at 0 (primary stability), 4, and 8 weeks (secondary stability). No significant difference in primary stability was found between STS and N-STS except for AMA (STS: NF 2434 ± 67 Hz, N-STS: NF 2572 ± 43 Hz; p = 0.62). Secondary stability increased significantly over time for both screw types (4-week: NF 3687 ± 36 vs. 3408 ± 45 Hz, PTV 1.4 ± 1.6 vs. -1.5 ± 1.8, PPF 236 ± 29 vs. 220 ± 34 N; 8-week: NF 3890 ± 39 vs. 3613 ± 31 Hz, PTV -3.2 ± 2.5 vs. -2 ± 4.3, PPF 248 ± 25 vs. 289 ± 28 N). Higher NF values for given PTV/PPF indicate potential clinical advantages. Significant differences between primary and secondary stabilities suggest osteointegration was mainly achieved in the 4-week group.

Patient-specific mechanical analysis of pedicle screw insertion in simulated osteoporotic spinal bone models derived from medical images.

Biomechanical study. To investigate the mechanical characteristics of bone models created from medical images. Recent advancements in three-dimensional (3D) printing technology have affected its application in surgery. However, a notable gap exists in the analyses of how patient's dimorphism and variations in vertebral body anatomy influence the maximum insertional torque (MIT) and pullout strength (POS) of pedicle screws (PS) in osteoporotic vertebral bone models derived from medical images. Male and female patients with computed tomography data were selected. Dimensions of the first thoracic (T1), fourth lumbar (L4), and fifth lumbar (L5) vertebrae were measured, and bone models consisting of the cancellous and cortical bones made from polyurethane foam were created. PS with diameters of 4.5 mm, 5.5 mm, and 6.5 mm were used. T1 PS were 25 mm long, and L4 and L5 PS were 40 mm long. The bone models were secured with cement, and the MIT was measured using a calibrated torque wrench. After MIT testing, the PS head was attached to the machine's crosshead. POS was then calculated at a crosshead speed of 5 mm/min until failure. The L4 and L5 were notably larger in female bone models, whereas the T1 vertebra was larger in male bone models. Consequently, the MIT and POS for L4 and L5 were higher in female bone models across all PS diameters than in male bone models. Conversely, the MIT for T1 was higher in male bone models across all PS; however, no significant differences were observed in the POS values for T1 between sexes. The mechanical properties of the proposed bone models can vary based on the vertebral structure and size. For accurate 3D surgical and mechanical simulations in the creation of custom-made medical devices, bone models must be constructed from patientspecific medical images.

Comparative Evaluation of Primary Stability in Truncated Cone Implants with Different Macro-Geometries in Low-Density Polyurethane Blocks Simulating Maxillary Sinus Rehabilitations

After tooth loss, particularly in the posterior maxilla, the alveolar ridges undergo bone resorption. Therefore, ensuring the appropriate quantity and quality of alveolar bone is crucial for accurate implant positioning and achieving optimal esthetic and functional results. This study aimed to evaluate biomechanical parameters (insertion torque: IT, removal torque: RT, and implant stability quotient: ISQ) of distinct truncated cone implant designs (Sinus-plant and SLC) on polyurethane blocks simulating type D3 and D4 bone. SLC implants exhibited significantly higher IT, RT, and ISQ values compared to Sinus-plant implants, except in the 10 pounds per cubic foot (PCF) density block with a cortical layer for the IT (24.01 ± 0.91 vs. 23.89 ± 1.66 Ncm). The IT values for SLC implants ranged from 13.95 ± 0.19 Ncm in the lowest density block to 37.94 ± 0.45 Ncm in the highest density block, consistently providing significantly higher primary stability with an ISQ of approximately 70 in the highest density block. Despite lower ISQ in the lowest density block (48.60 ± 0.52 and 48.80 ± 0.42 in buccolingual and mesiodistal directions), it was deemed acceptable considering the inadequate bone densities in the maxillary region. These findings on SLC suggest potential clinical advantages, including reduced procedure duration and costs, improved stability, and the possibility of immediate implant placement following sinus augmentation, thereby streamlining the rehabilitation process.

Case Report: The Sausage Technique using Anorganic Bovine Bone Mineral for Horizontal Bone Augmentation at the Crestal Part of a Posterior Mandibular Ridge: A Case Report.

Following tooth extraction, the alveolar bone goes through a natural remodeling process resulting in a significant bone resorption which may complicate dental implant placement without prior bone augmentation treatment. The sausage technique is a modified guided bone regeneration (GBR) method that has been successfully used for horizontal bone augmentation. This technique was developed to increase the bone growth at the alveolar crest. Although the sausage technique uses a combination of autograft chips and xenograft particles with a native collagen membrane, several studies have questioned whether adding autograft chips is essential for bone formation with guided bone regeneration. Moreover, harvesting the bone graft may increase the donor site morbidity and patient discomfort. This case report aimed to investigate the bone gain radiologically when the sausage technique was applied to treat a healthy, thirty-year-old patient with a horizontal defect in the posterior mandibular region using anorganic bovine bone mineral (ABBM) particles with Jason membrane, assess the implant primary stability in the augmented ridge, and present the surgical procedure steps in details. After nine months of healing, the cone-beam computed tomography (CBCT) revealed approximately 4.32 mm of bone gain at the alveolar crest in the buccal-lingual direction. The graft particles were well integrated into the newly formed bone. Two implants were inserted with an insertion torque of 35 N/cm. The ISQ values were 76 for the most anterior implant and 78 for the posterior implant. Within the limitations of this case report, the sausage technique using ABBM particles without autograft chips was an effective approach in achieving the prerequisite bone width at the crest in cases with horizontal bone defects.

An eight-year retrospective study on the clinical outcomes of laser surface-treated implants

PurposeTo retrospectively evaluate peri-implant bone loss and health status associated with the long-term use of laser surface-treated implants.MethodsFor control study, total of 23 titanium ASTM F136 grade 23 implants were placed in the edentulous molar area of the mandible. When the Implant Stability Quotient (ISQ) ≥ 70 and insertion torque value (ITV) ≥ 35–50 Ncm at the insertion site, an immediate provisional restoration was connected to the implant within a week after surgery. The definitive restorations were placed 2 months after surgery for all implants. 13 implants were immediately loaded, while 10 implants were conventionally loaded. For comparative study, Radiographs were taken from third years for and then annually for the subsequent eight years to monitor marginal bone loss.ResultsAfter eight year of implant installation, the average change in vertical bone loss was 0.009 mm (P < 0.001), while the average change in horizontal bone loss 8 year after implant placement was 0.026 mm (P < 0.001). The mean marginal bone loss was < 0.2 mm on average.ConclusionsIn this retrospective study, laser-treated implants exhibit a low rate of bone absorption around the implants.

Biomechanical Analysis of Pedicle Screw Reinsertion Along the Same Trajectory in a Validated 3D-Printed Synthetic Bone Model

To investigate the biomechanical properties of pedicle screw reinsertion along the same trajectory in a previously validated synthetic bone model. Twenty identical acrylonitrile butadiene styrene models of lumbar vertebrae were three-dimensional-printed. Screws were placed in the standard fashion into each pedicle. Models were separated into 2 equal groups, control and experimental. Experimental group screws were completely removed from their testing block and reinserted once. All screws in both groups were then forcibly removed. Continuous torque monitoring was collected on screw insertion torque (IT), removal torque, and reinsertion torque. Pullout strength (PO), screw stiffness (STI), and strain energy (STR) were calculated. There was no significant difference between control and experimental groups for PO (P=0.26), STI (P=0.55), STR (P=0.50), or IT (P=0.24). There was a significant decrease in reinsertion torque (54.5 N-cm±8.2 N-cm) from control IT (62.9 N-cm±8.4 N-cm, P=0.045) and experimental IT (67.5 N-cm±7.6 N-cm, P=0.0026). Strong correlations (Pearson's r>0.80) were seen between control IT against STR and PO, between each of the experimental torque measurements, and between experimental PO and STI. Despite a significant decrease in insertion torque, there is no significant loss of pedicle screw performance when a screw is removed and reinserted along the same trajectory.

Optimizing preoperative bone health assessment for adult spinal deformity: a prospective correlation analysis of intraoperative pedicle screw insertion torque and imaging modalities in Japan.

Prospective cohort study. This study aimed to identify the optimal preoperative bone health assessment for adult spinal deformity (ASD) surgery through correlation analysis between intraoperative pedicle screw (PS) insertion torque and various bone quality measures, including bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DEXA), Hounsfield unit (HU) by computed tomography (CT), and vertebral bone quality (VBQ) score by magnetic resonance imaging. Existing data on optimal assessment tools for ASD surgery are limited. The study included patients with ASD aged >60 years who underwent spinal corrective fusion surgery from the lower thoracic spine to the pelvis. The intraoperative PS insertion torque was measured using a torque meter. Pearson correlation coefficients were calculated between the PS insertion torque and the BMD, HU, and VBQ score. Preoperative bone quality was compared between the proximal junctional failure (PJF) and non-PJF groups. Thirty-one patients with 177 PS at T10, T11, and T12 were analyzed. The PS insertion torque showed a moderate positive correlation with lumbar spine BMD (r=0.59-0.69, p<0.01), total hip BMD (0.58-0.62, p<0.01), and HU value (r=0.58-0.66, p<0.01). However, the VBQ score did not show significant correlation (r=-0.28 to -0.23, p >0.05). Notably, a strong correlation was found between the PS insertion torque and the HU value for screws of the same size (r=0.71 and 0.74, p<0.01). The HU value at T12 and the PS insertion torque at T10 were significantly lower in the PJF group than in the non-PJF group. This study demonstrates a positive correlation between the PS insertion torque and HU value in the lower thoracic spine and a moderate correlation with BMD but not the VBQ score. Preoperative assessment using DEXA and CT is crucial for optimizing bone health management in ASD surgery.