Maximum insertion torque loss after miniscrew placement in orthodontic patients: A randomized controlled trial

Objectives To compare torque recordings of immediately loaded orthodontic miniscrews between insertion time and different post-placement timepoints (2 weeks, 4 weeks and removal time, respectively).Setting and sample population Parallel trial with an allocation ratio of 1:1. Eligibility criteria were needs of fixed orthodontic treatment, no systemic disease and absence of using drugs altering bone metabolism.Material and methods Patients received miniscrews, 2.0 mm diameter and 10 mm length. All miniscrews underwent inter-radicular placement, and they were placed in the maxilla or in the mandible, palatally or buccally. No pre-drilling was performed. Miniscrews were loaded immediately after the insertion and were used for distalization, intrusion, extrusion, mesialization or indirect anchorage. Patients were randomly divided into three groups. For each patient, Maximum Insertion Torque (MIT) was evaluated at baseline. MIT was measured again after 2 weeks and after 4 weeks by tightening the screw a quarter of turn in Groups 1 and 2, respectively. At the end of the treatment, maximal removal torque was evaluated in Group 3. Torque variation with respect to insertion time was considered as the primary outcome. Baseline and longitudinal differences were tested using the linear mixed-effects (LME) model.Results Forty seven patients and 74 miniscrews were followed up. An association existed between maximum insertion torque and the observation time. A torque decrease of 26.9% and 30% after 2 weeks was observed for mandibular and maxillary miniscrews, respectively. After 1 month, torque values were similar to the baseline records. The overall success rate was 79.7%. No serious harm was observed.Conclusions Maximum insertion torque undergoes a loss during the first 2 weeks, and its values may depend on the insertion site and the anchorage purpose. Removal torque value is almost the same as the initial torque after 1 month

Immediate versus delayed loading: comparison of primary stability loss after miniscrew placement in orthodontic patients-a single-centre blinded randomized clinical trial

Introduction: The aim of this randomized clinical trial was to compare torque recordings at insertion time and 1 week post-placement between immediately loaded orthodontic miniscrews and an unloaded control group. Trial design: This RCT was designed as parallel with an allocation ratio of 1:1. Methods: Eligibility criteria to enroll patients were: needs of fixed orthodontic treatment, no systemic disease, absence of using drugs altering bone metabolism. All patients were consecutively treated in a private practice and the miniscrews were placed by the same author. Patients received ORTHOImplant (3M Unitek) miniscrews and they were blindly divided in two groups: group 1 screws were unloaded between T0 and T1, group 2 received immediately loaded screws with NiTi coil. For each patient, maximum insertion torque (MIT) was evaluated at T0. After 1 week, without loading, the screw torque was measured again (T1) and at the end of the treatment maximal removal torque was evaluated (T2). Torque variation in the first week was considered as the primary outcome. Randomization: A randomization list was created for the group assignment, with an allocation ratio of 1:1. Blinding: The study was single blinded in regard of the statistical analysis. Results: Patients enrolled in the clinical trial were 51 for a total of 81 miniscrews. The recruitment started in November 2012 and the observation period ended in August 2014. Twenty-six and twenty-five patients were analysed in group 1 and 2, respectively. The MIT mean in each placement time was 18.25 Ncm (SD = 3.00), 11.41 Ncm (SD = 3.51) and 10.52 Ncm (SD = 5.14) at T0, T1, and T2 time, respectively. In group 1, the torque decrease between T1 and T0 was statistically higher compared to group 2 (P value = 0.003). Statistically significant effects of the placement times on MIT were found (P value <0.0001). No serious harm was observed. Limitations: This study was performed using only direct force on the miniscrew and not using the miniscrew as an indirect anchorage. It was not possible to obtain quantitative data on bone quality or root proximity to miniscrews. Conclusions: A significant stability loss was observed in the first week in both groups; Group 1 showed a statistically higher torque loss in the first week when compared to the immediately loaded group. There were statistically significant effects of the measurement times on MIT and of the miniscrew location on MIT. The overall failure rate was 7.4%. Trial registration: This trial was not registered. Protocol: The protocol was not published before trial commencement

Immediately Loaded Implants in Rehabilitation of the Maxilla: A Two-Year Randomized Clinical Trial of Guided Surgery versus Standard Procedure

Purpose: The aim of this study was to evaluate the outcome of a guided surgery protocol versus a conventional protocol. Materials and Methods: Twenty-six patients were randomly assigned to Guided Surgery or Conventional Surgery. In test group implants were placed in the maxilla using a tooth supported model-based surgical guide with a minimally invasive flap and immediately loaded. In control group implants were inserted with an open flap surgery following a prosthetic stent and immediately loaded.Conclusions: Implants can successfully integrate in the posterior maxilla using a guided surgery approach with immediate loading. The use of guided surgery helped to reduce the surgery duration, pain intensity, related analgesic consumption, and a more predictable provisional installatio

Internal bone temperature change during guided surgery preparations for dental implants: an in vitro study

Purpose: The aim of this pig model study was to verify whether the use of devices (surgical templates) or procedures (flapless or flap) of guided surgery may cause a potentially pathologic increase of temperature during the bone preparation. Materials and Methods: In this in vitro study, pig ribs with mean cortical thickness of 1.90 mm were used. Open-flap and flapless guided surgery (experimental groups OGS and FGS) and openflap and flapless conventional technique (control groups OSS and OFS) were performed. Temperature changes were recorded at a distance of 0.5 mm from the final test osteotomy by 2 thermocouples at depths of 1.5 (point A) and 12 mm (point B). Data were collected from 80 measurements, 10 for each group. Results: A statistically significant increase of temperature was reported for the FGS and OGS groups considering the measurement at point A (mean \u394t 4.81 degrees and 4.21 degrees, respectively). The measurement at Point B for the FGS group compared to the FSS group did not differ significantly for the 3-mm drill, nor did the OSS group with the 2-mm drill. Conclusions: Site preparation with surgical stents generated higher bone temperature than conventional drilling. However, this heat generation did not reach temperature levels dangerous for the bon