Placement Torque Research Articles

An in vitro study on the impact of the torque after repeated use of the implant handpiece: An original research

Introduction: Extreme repeated use of the dental implant handpiece may cause aging of the handpiece through heat generation of the implant motor and affect its lifespan. We aim to conduct an in-vitro study on the impact of the torque after repeated use of the implant handpiece. Materials and methods: Two types of implant handpiece systems NSK, and SAESHIN were applied. The output torque was calibrated using a digital torque gauge. The experiment was done under the setting torque value of 35 Ncm (implant placement torque) and 50 Ncm (overloading torque condition) and 30 times per set; a total of 5 sets were performed (N = 150). Results: NSK and SAESHIN implant handpieces depicted significant differences in output torque output at the setting torques of 35 Ncm and 50 Ncm (P <.001). The type of implant handpiece and repeated use influenced the output torque (P <.001). Conclusion: Notable changes were noted due to repeated use, and the implant handpiece should be achieved and repaired during long-term use. Moreover, for successful implant results in dental clinics, the output torque of the implant handpiece system should be checked before implant placement.

Influence of late removal after treatment on the removal torque of microimplants.

ObjectiveTo compare the removal torque of microimplants upon post-use removal and post-retention removal and to assess the influencing factors.MethodsThe sample group included 241 patients (age, 30.25 ± 12.2 years) with 568 microimplants. They were divided into the post-use (microimplants removed immediately after use or treatment) and post-retention (microimplants removed during the retention period) removal groups. The removal torque in both groups was assessed according to sex, age, placement site and method, and microimplant size. Pearson correlation and multiple linear regression analyses were performed for evaluating variables influencing the removal torque.ResultsThe mean period of total in-bone stay of microimplants in the post-retention removal group (1,237 days) was approximately two times longer than that in the post-use removal group (656.28 days). The removal torques in the post-retention removal group (range, 4–5 N cm) were also higher than those in the post-use removal group. The mandible and pre-drilling groups demonstrated higher placement and removal torques than did the maxilla and no-drilling groups, respectively. In the no-drilling post-use removal group, the placement torque and microimplant length positively correlated with the removal torque. In the post-retention removal group, unloading in-bone stay period and microimplant diameter positively correlated with the removal torque in the no-drilling and pre-drilling methods, respectively.ConclusionsThe removal torques differed according to the orthodontic loading and removal time of microimplants. With prolonged retention of microimplants inserted using the no-drilling method, the removal torque was clinically acceptable and positively correlated with the unloading in-bone stay period.

Significance of bone morphology and quality on the primary stability of orthodontic mini-implants: in vitro comparison between human bone substitute and artificial bone.

This study evaluated artificial bone models against ahuman bone substitute to assess the primary stability of orthodontic mini-implants (OMIs) at varying implant sites with different morphologies and qualities. Atotal of 1200 OMI placements of four types were inserted into four artificial bone models of different density (D1, D2, D3, D4) and into ahuman bone substitute (HB). The implants varied in diameter (2.0 and 2.3 mm) and length (9and 11 mm). Each specimen had four implant sites: no defect, one-wall defect, three-wall defect, and circular defect. The implant stability quotient (ISQ) values were measured using resonance frequency analysis (RFA) and insertion placement torque values (IPT) were assessed for primary stability. Correlation analysis was performed to evaluate the different models. The highest IPT value was registered for the 2.0 mm × 11 mm implant inserted into D1 with no defect (37.53 ± 3.02 Ncm). The lowest ISQ value was measured for the 2.3 mm × 9 mm OMI inserted into D3 with acircular defect (12.33 ± 5.88) and the highest for the 2.3 mm × 9 mm implant inserted into HB with no defect (63.23 ± 2.57). Astrong correlation (r = 0.64) for IPT values and avery strong correlation (r = 0.8) for ISQ values was found between D2 and HB. Bone defects and bone quality affected the primary stability of implants in terms of ISQ and IPT values. Results for bone model D2 correlated very well with the HB substitution material.

Long-term evaluation of factors affecting removal torque of microimplants

BackgroundThe current study aimed to evaluate factors affecting the long-term stability of microimplants using removal torque and the correlation between removal torque and clinical variables.Materials and methodsThis research evaluated 703 microimplants placed in 354 patients (mean age: 30.4 ± 12.1 years). The removal torque was evaluated according to various clinical variables including sex, age, placement site, microimplant size, and placement method (self-drilling versus pre-drilling). Pearson correlation and stepwise multiple linear regression analyses were performed to investigate different variables and their association with removal torque.ResultsThe mean removal torque was significantly higher in the mandible (4.46 N cm) than in the maxilla (3.73 N cm). The values in the posterior teeth/retromolar areas were significantly higher than those in the anterior teeth area. There were no significant difference in terms of sex. Teenagers had a lower removal torque than older adults in the mandible, but not in the maxilla. Microimplants with a greater length and diameter, except for those with a greater diameter in the maxilla, was associated with a higher removal torque. Regardless of placement torque, the removal torque convergently reached approximately 4 N cm in both placement methods. The removal torque was significantly correlated with screw length in the self-drilling group and with diameter in the pre-drilling group.ConclusionsRemoval torque was related with placement site, age, placement method, and length and diameter of microimplants.

Anterior Glenoid Reconstruction With Distal Tibial Allograft: Biomechanical Impact of Fixation and Presence of a Retained Lateral Cortex.

Background:Glenoid reconstruction with distal tibial allograft (DTA) is a known surgical option for treating recurrent glenohumeral instability with anterior glenoid bone loss; however, biomechanical analysis has yet to determine how graft variability and fixation options alter the torque of screw insertion and load to failure.Hypothesis:It was hypothesized that retention of the lateral cortex of the DTA graft and the presence of a washer with the screw will significantly increase the maximum screw placement torque as well as the load to failure.Study Design:Controlled laboratory study.Methods:Whole, fresh distal tibias were used to harvest 28 DTA grafts, half of which had the lateral cortex removed and half of which had the lateral cortex intact. The grafts were secured to polyurethane solid foam blocks with a 2-mm epoxy laminate to simulate a glenoid with an intact posterior glenoid cortex. Grafts underwent fixation with 4.0-mm cannulated drills, and screws and washers were used for half of each group of grafts while screws alone were used for the other half, creating 4 equal groups of 7 samples each. A digital torque-measuring screwdriver recorded peak torque for screw insertion. Constructs were then tested in compression with a uniaxial materials testing system and loaded in displacement control at 100 mm/min until at least 3 mm of displacement occurred. Ultimate load was defined as the load sustained at clinical failure.Results:The use of a washer significantly improved the ultimate torque that could be applied to the screws (+cortex and +washer = 12.42 N·m [SE, 0.82]; –cortex and +washer = 10.54 N·m [SE, 0.59]) (P < .0001), whereas the presence of the native bone cortex did not have a significant effect (+cortex and –washer = 7.83 N·m [SE, 0.40]; –cortex and –washer = 8.03 N·m [SE, 0.56]) (P = .181).Conclusion:In a hybrid construct of fresh cadaveric DTA grafts secured to a foam block glenoid model, the addition of washers was more effective than the retention of the lateral distal tibial cortex for both load to failure and peak torque during screw insertion.Clinical Relevance:This biomechanical study is relevant to the surgeon when choosing a graft and selecting fixation options during glenoid reconstruction with a DTA graft.

Assessment of Insertion Torque of Mini-implant and Its Correlation with Primary Stability and Pain Levels in Orthodontic Patients

The aim of this study was to assess the insertion torque of the mini-implant used in orthodontic patients and to assess the correlation between the insertion torque, primary stability, and perception of pain in patients undergoing orthodontic therapy with mini-implant-augmented anchorage. Among the patients undergoing orthodontic therapy, 31 samples who required mini-implant for anchorage purpose were selected. A total of 59 mini-implants were placed in these patients. This included interradicular mini-implants and extra-alveolar mini-screws. Immediately after placement, the insertion torque in all these was measured using a digital torque meter and primary stability was assessed by identifying any mobility of the implant placed. Primary stability was noted at two time intervals immediate post-placement and 1 week after that. All the mini-implants that were considered in this study were immediately loaded. Patients were asked to record any pain experienced on the visual analog scale (VAS) score sheet at 24 hours and 1 week post-placement. Among the mini-implants placed, those with 2 mm diameter needed higher placement torque, i.e., infrazygomatic crest mini-implants and buccal shelf mini-implants were placed with average placement torque of 10.08 and 10.25 N cm, respectively. Extra-alveolar screws caused more pain, especially higher in the mandible than the maxilla. Decrease in pain scores was noted from T0 to T1 in almost all the cases. Thicker mini-implant needed more insertion torque and highest insertion torque was recorded with extra-alveolar screws. No direct correlation could be obtained with the pain levels experienced by the patients and with the primary stability of the mini-implants. Mini-implants placed with an insertion torque above the recommended range tend to fail and break more often. Patients placed with extra-alveolar bone screws reported more pain than that of the smaller-dimension mini-implant.

Influence of pre-drilling diameter on the stability of orthodontic anchoring screws in the mid-palatal area.

The aim of this study was to investigate the stability of orthodontic anchor screws (OASs) in the mid-palatal area according to pre-drilling diameter. The success rate of 161 OASs (83 patients, φ2.0 mm, 6.0 mm in length) placed in a corresponding area to the mesial and distal borders of the first molar (mesial zone and distal zone) was assessed according to placement location and pre-drilling diameter (1.2 and 1.5 mm). Placement torque values from 73 OASs with a pre-drilling diameter of 1.2 mm were compared between success and failure groups. The success rates of OASs pre-drilled with φ1.2 and 1.5 mm were 94.5% and 83.0%, respectively (P < 0.05); corresponding rates in the mesial zone were 100.0% and 77.3% (P < 0.005), and those in the distal zone were 89.2% and 88.6%, respectively. Placement torques of OASs predrilled with φ1.2 mm in the success and failure groups were 25.9 and 19.2 N·cm, respectively (P < 0.05). A smaller pre-drilling diameter was associated with a higher success rate of OASs in the mid-palatal area, especially in the mesial zone. When pre-drilling diameter of 1.2 mm was used for φ2.0 mm OAS, greater placement torque was indicative of greater OAS stability.

Effect of repeated use of an implant handpiece on an output torque: An in-vitro study.

PURPOSEThis study aimed to evaluate the effect of repeated use of an implant handpiece under an implant placement torque (35 Ncm) and overloading torque condition (50 Ncm) on an output torque.MATERIALS AND METHODSTwo types of implant handpiece systems (Surgicpro/X-DSG20L [NSK, Kanuma, Japan] and SIP20/CRB46LN [SAESHIN, Daegu, South Korea]) were used. The output torque was measured using a digital torque gauge. The height and angle (x, y, and z axes) of the digital torque gauge and implant handpiece were adjusted through a jig for passive connection. The experiment was conducted under the setting torque value of 35 Ncm (implant placement torque) and 50 Ncm (overloading torque condition) and 30 times per set; a total of 5 sets were performed (N = 150). For statistical analysis, the difference between the groups was analyzed using the Mann-Whitney U test and the Friedman test was used to confirm the change in output torque (α=.05).RESULTSNSK and SAESHIN implant handpieces showed significant differences in output torque results at the setting torques of 35 Ncm and 50 Ncm (P<.001). The type of implant handpiece and repeated use influenced the output torque (P<.001).CONCLUSIONThere may be a difference between the setting torque and actual output torque due to repeated use, and the implant handpiece should be managed and repaired during long-term use. In addition, for successful implant results in dental clinics, the output torque of the implant handpiece system should be checked before implant placement.

Retrospective Clinical Study of 453 Novel Tapered Implants Placed in All Bone Types: Survival Rate Analysis Up to 2 Years of Follow-Up.

The aim of this retrospective study was to report the survival rate of a novel hybrid hydrophilic dental implant design for all bone types. This study evaluated the data collected from patients who received at least one implant to support a full-arch, partial, or single-crown dental rehabilitation in the maxilla or mandible. Implant survival rate was evaluated according to the clinical area and bone type, loading protocol, implant length and diameter, and placement torque. A total of 453 tapered hybrid implants placed in 101 patients (mean age: 56.39 ± 12.98 years) were evaluated, and the survival rate was 99.6%. The follow-up period was up to 24 months. Regarding bone quality, types I, III, and IV presented a 100% survival rate, whereas type II presented a 99.3% survival rate. The vast majority of implants were immediately loaded (443 implants), which achieved placement torques between 32 and 60 Ncm or higher, and presented an implant survival rate of 99.5%. An overall survival rate of 99.6% was found for hydrophilic hybrid dental implants when placed in all bone types, and no statistically significant difference was observed between them. However, further studies should be necessary to confirm these preliminary results.

Analysis in vitro of the insertion torque of hybrid tapered implants with different types of instrumentation and two clinical cases report

Aim The aim of this study was to observe the behavior of the hybrid implants, evaluating the insertion test with different drilling protocols and present two case reports of hybrid implant placed in the upper arch. Materials and methods For the in vitro study 50 implants were placed in 2 different types of synthetic bone blocks composed of rigid solid polyurethane (high density, type I, and low density, type IV). The implants were divided into five groups (n=10): Group 1 (Test) hybrid/conical implants of 3.75 mm x 13 mm placed in a high density bone block with oversized instrumentation; Group 2 (Control) cutting/cylindrical of 3.75 mm x 13 mm, placed in a high density bone block with regular instrumentation; Group 3 (Test) hybrid/conical implants of 4.3 mm x 13 mm placed in a low density bone block with undersized instrumentation; Group 4 (Test) hybrid/conical implants of 4.3 mm x 13 mm placed in a low density bone block with regular instrumentation; Group 5 (Control) compact/conical implants of 4.3 mm x 13 mm placed in a low density bone block with regular instrumentation. Two cases are reported of hybrid implants placed in the maxilla with 12-month follow up. Results No significant difference was observed between hybrid/conical implants and the control group, according to final placement torque in high and low density bone. However, undersized instrumentation showed a significantly increased final torque placement for hybrid/conical implant. Conclusions Implant macrostructure, bone instrumentation technique influence the insertion torque for hybrid/conical implants. At the 12-month follow-up the implants were stable.

Capacity to Maintain Placement Torque at Removal, Single Load-to-Failure, and Stress Concentration of Straight and Angled Abutments.

Because the main complication of implant-supported prostheses is torque loosening and/or fixation screw fracture, the goal of this study was to evaluate the torque before and after fatigue (screw placement and removal, respectively), single load-to-failure (compression test), and stress concentration of straight and angled abutments. Eighty implants were included in polyurethane cylinders. Half of the implants received straight abutments (group S, n = 40) and the other half received angled abutments (group A, n = 40). The abutments for cemented prostheses were installed with a torque of 20 Ncm. Eighty titanium structures were machined and cemented on the abutments with zinc-phosphate cement. After storage for 24 hours, half of the specimens had their torque loosening evaluated and were then immediately submitted to a compressive test in a universal testing machine (1 mm/minute, 1,000 kgf), while the other half were subjected to cyclic fatigue (200 N at 2 Hz for 2 × 106 cycles at 37°C) as an aging protocol (n = 20 from each group). The aged samples then had their torque loosening measured and were also submitted to the compression test. Representative samples were evaluated by scanning electron microscopy. Two bidimensional models similar to the in vitro specimens were created and analyzed using the finite element method to evaluate the stress concentration. Data from the in vitro tests were submitted to two-way analysis of variance and Tukey test, both with significance at P = .5. The results show that angled abutments are less capable of maintaining the installation torque and are less resistant during the single load-to-failure test. The von Mises stress concentration was higher for group A in the cervical region. The straight abutments have better prognosis than angled abutments and less susceptibility to mechanical failures.

The effect of implant placement torque on crestal bone remodeling after 1 year of loading.

PurposeThe aim of this study was to evaluate and compare crestal bone levels (CBLs) after 1 year of loading of self-tapping bone condensing implants placed with high insertion torque (IT) compared to those placed with lower IT.Materials and methodsA retrospective chart review of 66 consecutive patients who received at least one self-tapping bone condensing implant and were in function for at least 1 year was conducted. On the basis of intrasurgical notes documenting the implant IT, the patient population was divided into group A (implant IT, >55 Ncm) and group B (IT, <55 Ncm). Radiographs taken immediately after insertion and during annual follow-up appointments were evaluated for detecting crestal bone loss. The relationship between IT and crestal bone loss, bone density, and jaw location were analyzed, and a P-value of 0.05 was considered to be statistically significant.ResultsA total of 113 self-tapping bone condensing NobelActive™ implants were placed. The average follow-up period from the placement of the implant restoration was 12.87 (±4.83) months. Six implants were classified as failures resulting in overall survival rate of 94.6%. Implants in group A had a mean IT of 67.35 ± 4.0 Ncm, whereas implants in the group B had a mean IT of 37.9 ± 12.62 Ncm. Implants in group A had statistically significant crestal bone loss compared to implants in group B (0.95 ± 1.60 and 0.18 ± 0.68 mm, respectively). Group A implants placed in the mandible showed significantly more pronounced crestal bone loss (2.12 ± 1.99 mm) compared to those placed in the maxilla (0.25 ± 0.65 mm; P<0.05); however, this was not the case in group B implants.ConclusionImplants inserted with high IT (>55 Ncm) showed more peri-implant bone remodeling than implants inserted with a less assertive IT (<55 Ncm). Bone density and jaw location affect IT and CBLs.

The Effect of Osteotomy Dimension on Implant Insertion Torque, Healing Mode, and Osseointegration Indicators: A Study in Dogs.

This study investigated the effect of the osteotomy diameter for implant placement torque and its effect on the osseointegration. Eight male beagle dogs received 48 implants (3.75 mm × 10 mm) in their right and left radius, 3 implants per side and allowed to heal for 3 weeks. Three experimental groups were evaluated. Group 1: implant with an undersized osteotomy of 3.0 mm; group 2: osteotomy of 3.25 mm, and group 3: osteotomy of 3.5 mm. The insertion torque was recorded for all implants. Histological sectioning and histometric analysis were performed evaluating bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Implants of group 1 presented statistically higher insertion torque than those of groups 2 and 3 (P < 0.01). No differences in BIC or BAFO were observed between the groups. From a morphologic standpoint, substantial deviations in healing mode were observed between groups. Based on the present methodology, the experimental alterations of surgical technic can be clinically used with no detrimental effect over the osseointegration process.

Are assessments of damping capacity and placement torque useful in estimating root proximity of orthodontic anchor screws?

Placement torque and damping capacity may increase when the orthodontic anchor screws make contact with an adjacent root. If this is the case, root contact can be inferred from the placement torque and damping capacity. The purpose of this study was to verify the detectability of root proximity of the screws by placement torque and damping capacity. For this purpose, we investigated the relationship among placement torque, damping capacity, and screw-root proximity. The placement torque, damping capacity, and root proximity of 202 screws (diameter, 1.6mm; length, 8.0mm) were evaluated in 110 patients (31 male, 79 female; mean age, 21.3±6.9years). Placement torque was measured using a digital torque tester, damping capacity was measured with a Periotest device (Medizintechnik Gulden, Modautal, Germany), and root contact was judged using cone-beam computed tomography images. The rate of root contact was 18.3%. Placement torque and damping capacity were 7.8N·cm and 3.8, respectively. The placement torque of screws with root contact was greater than that of screws with no root contact (P<0.05; effect size, 0.44; power,<0.8). Damping capacity of screws with root contact was significantly greater than that of screws with no root contact (P<0.01; effect size,>0.5; power,>0.95). It was suggested that the damping capacity is related to root contact.

Agreement of Power Measures between Garmin Vector and SRM Cycle Power Meters

ABSTRACTThis study aimed to determine if the Garmin Vector (Schaffhausen, Switzerland) power meter produced acceptable measures when compared with the Schoberer Rad Messetechnik (SRM; Julich, Germany) power meter across a range of high-intensity efforts. Twenty-one well-trained cyclists completed power profiles (seven maximal mean efforts between 5 and 600 s) using Vector and SRM power meters. Data were compared using assessments of heteroscedasticity, t tests, linear regression, and typical error of estimate (TEE). The data were heteroscedastic, whereby the Vector pedals increasingly overestimated values at higher power outputs; however, t tests did not identify any significant differences between power meters (p > .05). Using linear regression, Vector data were fit to an SRM equivalent (slope = .99; intercept = −9.87) and TEE produced by this equation was 3.3% (3.0%–3.8%). While the data shows slight heteroscedasticity due to differing strain-gauge placement and resultant torque measurement variance, the Vector appears acceptable for measures of power output across various cycling efforts.

Measuring bone density at orthodontic miniscrew implantation sites using microcomputed tomography.

This study was performed to determine the accuracy of measurements of bone mineral density (BMD) and cortical bone thickness (CBT) at miniscrew implantation sites in small animals and to verify the usefulness of in vivo microcomputed tomography (micro-CT). Rat femurs were scanned before and after placing miniscrews using in vivo micro-CT. The images were superimposed using a subtraction method with bone volume measurement software. At each screw site, the total BMD was calculated as the average BMD of a cylinder 1.6 mm in diameter and 2.0 mm in depth, while the cortical BMD was the average BMD of a cylinder 1.6 mm in diameter and 1.0 mm in depth. CBT was measured three times on transaxial images of the rat femurs, and the average value was used. All miniscrews were placed using the maximum torque, verified with a digital torque tester. To verify the usefulness and accuracy of in vivo micro-CT, CBT on micro-CT images was compared with that measured on histologic sections. Significant correlations were observed between placement torque and cortical BMD (R = 0.572), total BMD (R = 0.732), and CBT (R = 0.788). There was a significant correlation between CBT measured via field-emission scanning electron microscopy images and CBT measured with in vivo micro-CT (R = 0.974). The BMD over a narrow range can be measured accurately in small animals with high reproducibility of the trabecular structure using a combination of high-resolution in vivo micro-CT and image superimposition using a three-dimensional subtraction method.

Maxillary sinus perforation by orthodontic anchor screws.

To facilitate safe placement of orthodontic anchor screws (miniscrews), we investigated the frequency of maxillary sinus perforation after screw placement and the effect of sinus perforation on screw stability. Maxillary sinus perforations involving 82 miniscrews (diameter, 1.6 mm; length, 8 mm) were evaluated using cone-beam computed tomography. All miniscrews were placed in maxillary alveolar bone between the second premolar and first molar for anchorage for anterior retraction in patients undergoing first premolar extraction. The placement torque and screw mobility of each implant were determined using a torque tester and a Periotest device, and variability in these values in relation to sinus perforation was evaluated. Eight of the 82 miniscrews perforated the maxillary sinus. There was no case of sinusitis in patients with miniscrew perforation and no significant difference in screw mobility or placement torque between perforating and non-perforating miniscrews. The sinus floor was significantly thinner in perforated cases than in non-perforated cases. A sinus floor thickness of 6.0 mm or more is recommended in order to avoid miniscrew perforation of the maxillary sinus.

Impact of extracorporeal shock-wave therapy on the stability of temporary anchorage devices in adults: A single-center, randomized, placebo-controlled clinical trial

In this randomized, placebo-controlled clinical trial, we investigated the effect of noninvasive extracorporeal shock waves on the stability of temporary anchorage devices (TADs) under orthodontic loading. Thirty adult orthodontic patients of the Bernhard Gottlieb University Clinic in Vienna, Austria, were enrolled in this clinical trial and allocated by block randomization (size, 4) in a 1:1 ratio to either the treatment or the placebo group. Randomization was performed with software, and the allocations were concealed in sealed envelopes. Eligibility criteria included healthy adult patients with mesially directed orthodontic movement of the mandibular second molar into the extraction site of the mandibular first molar. The fixed orthodontic devices included active superelastic coil springs (200cN) and TADs in the mandibular alveolar bone. Blinding was performed for the subjects and the outcome assessor. The treatment group received 1 shock-wave application with 1000 impulses at 0.19 to 0.23mJ per square millimeter in the region of the TADs. The placebo group was treated with a deactivated shock-wave applicator and acoustic sham. The TADs positions were evaluated at placement and after 4months. The reliability and precision of the impression process of the TADs were evaluated in an in-vitro model. Thirteen participants finished the investigation successfully in the treatment group but only 12 finished in the placebo group because 1 TAD loosened. The difference of the total TAD displacement for the 4-month time period between the placebo and treatment groups was 0.17±0.95mm (95% CI: -0.96, 0.62). No statistically significant difference between the 2 groups was found when sex was evaluated. Primary stability of the TADs as measured by placement torque, amount of tooth movement, and age of the patients did not influence displacement of the TADs. The reliability and precision of TAD impressions were confirmed. No unintended pernicious effects occurred after shock-wave treatment during the study period. A single application of extracorporeal shock-wave treatment did not improve the stability of the TADs during orthodontic loading. Sufficient interradicular space should be provided to minimize the risk of periodontal and dental root defects. This trial was registered at https://clinicaltrials.gov. The protocol was published before trial commencement, NCT01695928. No funding or conflict of interest to be declared.

Comparative study of the primary stability of self-drilling and self-tapping orthodontic miniscrews

The purpose of this study was to determine the influence of self-tapping and self-drilling placement techniques on the stability of miniscrews. We included 70 orthodontic patients who received miniscrews (140 screws). Miniscrews measuring 1.6 mm in diameter and 8 mm in length were placed using the self-tapping (35 patients, 70 screws) and self-drilling (35 patients, 70 screws) methods. We examined the success rates, placement torque values, Periotest (Medizintechnik Gulden, Bensheim, Germany) values, rates of root contact, and influence of root contact on mobility. Cone-beam computed tomography was used to evaluate root contact. Miniscrews that endured an orthodontic force for 6 months or more were considered successful. The success rates of the miniscrews were approximately 96% with either placement technique. The placement torques were 7 and 7.5 N cm in the self-tapping and self-drilling miniscrews, respectively (P>0.05). The Periotest values of the self-drilling method were significantly greater than those of the self-tapping method. The Periotest values of the self-drilling miniscrews with root contact were significantly greater than those with no root contact. Both placement techniques showed high stability in the maxillary bone, although the self-drilling miniscrews with root contact had greater mobility. Special attention to root contact further improves the stability of the self-drilling miniscrews.

Torque Analysis of Self-drilling Mini-screws placed with and without a Pilot Drill: A Canine Study

ABSTRACTPurposeThe use of temporary anchorage devices (TADs), such as mini-screws, palatal implants and mini-plates, has become a popular treatment option in orthodontics. The objectives of this study were: (1) to compare the success rates of self-drilling mini-screws placed with or without use of a pilot drill, (2) to evaluate the implant placement torque (IPT) of self-drilling miniscrews and (3) to measure the removal torque of self-drilling mini-screws.Materials and methodsSix American foxhounds served as subjects in this study. Three OsteoMed self-drilling mini-screws (1.6 mm diameter and 8 mm length) were planned to be placed in each side of the mandible between the roots of the teeth canine/premolar 1 (PM1), PM2/PM3 and PM3/PM4. The sites were allocated randomly in: (1) control group—mini-screws placed with pilot drill and (2) test group—mini-screws placed without pilot drill (self-drilling). The implant placement torque (IPT) and the number of turns performed by the mini-screws during placement were measured. After a healing period of 6 weeks, the mini-screws were removed, and the removal torque was measured.ResultsA total of 33 mini-screws were placed in six animals. After 6 weeks, the success rate for the control and test groups were 46.7 and 80% respectively (difference not statistically significant). There was no statistically significant difference in the terminal mean IPT values and the mean number of turns for failed and successful mini-screws. The difference between the mean IPT values at the 3rd turn during mini-screw placement in the successful and failed mini-screws (5.56 and 14.03 Ncm respectively) was statistically significant (p &lt; 0.01).ConclusionThere was no statistically significant difference in the success rate between self-drilling mini-screws that did or did not have osteotomies (46vs80% respectively). However, the IPT at the third revolution for successful mini-screws averaged 5.56 Ncm (p &lt; 0.01).How to cite this articleZambon-Fagundes DA, Kerns DG, Hallmon WW, Solomon ES. Torque Analysis of Self-Drilling Mini-screws placed with and without a Pilot Drill: A Canine Study. J Contemp Dent 2014;4(2):77-86.