Titanium Screws Research Articles

Nanoparticle ultrasonication: a promising approach for reducing bacterial biofilm in total joint infection-an in vivo rat model investigation.

While the benefits of sonication for improving periprosthetic joint infection (PJI) are well-documented, its potential therapeutic effect against bacterial biofilm remains unstudied. This study aimed to investigate the safety and efficacy of a novel nanoparticle ultrasonication process on methicillin-resistant Staphylococcus aureus (MRSA) bacterial biofilm formation in a PJI rat model. This novel ultrasonication process was designed to remove attached bacterial biofilm from implant and peri-articular tissues, without damaging native tissues or compromising implant integrity. Twenty-five adult Sprague-Dawley rats underwent a surgical procedure and were colonized with intra-articular MRSA, followed by the insertion of a titanium screw. Three weeks after the index surgery, the animals received a second procedure during which the screws were explanted, and soft tissue was sampled. The intraoperative use of the nanoparticle sonication treatment was employed to assess the device's safety, while ex vivo treatment on the retrieved tissue and implants was used to evaluate its efficacy. Clinical and histological assessments did not indicate any macro- or micro-damage to the host tissue. Sonication of the retrieved tissues demonstrated an average bacterial removal of 2 × 103CFU/mL and 1 × 104CFU/gram of tissue. Compared to the standard-of-care group (n = 10), implants treated with sonication (n = 15) had significantly lower remaining bacteria, as indicated by crystal violet absorbance measurements (P = 0.012). This study suggests that nanoparticle sonication technology can successfully remove attached bacterial biofilms from explanted orthopedic hardware and the joint capsule, without negatively affecting native tissue. The study provides initial results supporting the potential of nanoparticle sonication as an adjuvant treatment option during a DAIR (debridement, antibiotics, and implant retention) procedure for PJI, paving the way for future clinical trials.

Evaluation of cortical bone thickness at the nasomaxillary and zygomaticomaxillary buttresses using cone-beam computed tomography imaging for Le Fort I osteotomy

Background/PurposeStudies have indicated that 50%–55% of the population have malocclusion, and approximately 5%–10% require orthognathic surgery to correct this condition. Optimal placement of plates and screws significantly affects the success rate of the surgery and postoperative stability. This study evaluates the cortical thickness of the maxillary bone in the nasomaxillary and zygomaticomaxillary buttress regions in Taiwanese patients based on cone-beam computed tomography (CBCT) images. Materials and methods128 Patients undergoing Le Fort I osteotomy were selected for this study. Their CBCT images were input into medical imaging software to simulate the placement of titanium screws and plates. The cortical bone thickness at these positions was measured to assess the thickness in the nasomaxillary buttress (surrounding the nasal opening) and the zygomaticomaxillary buttress (surrounding the maxillary zygomatic process). Associations of these thicknesses with gender, age, and screw position were analyzed. ResultsIn the nasomaxillary region, cortical bone was thicker on the upper and lower vertical regions, with men generally having thicker bone. The zygomaticomaxillary region had increased thickness near the zygomatic end and distal region. Younger adults had significantly greater bone thickness in certain areas than those over 30 years. ConclusionThe nasomaxillary region's upper and lower vertical regions and the zygomatic end in the zygomaticomaxillary region provide optimal screw placement sites. Bone thickness differences by gender and age suggest occlusal force and age-related bone resorption as influencing factors.

Management of pediatric ankle fractures: comparison of biodegradable PLGA implants with traditional metal screws.

The relevance of biodegradable implants has gained more importance in modern clinical practice. The study aimed to evaluate the effects and outcomes of ankle fracture treatment with absorbable implants compared to metal screws. These implants are made from poly l-lactic-co-glycolic acid (PLGA), however, there are several other materials available on the market. In a retrospective review, a total of 128 patients were under observation, with distal tibial fracture types ranging from Salter-Harris II-IV. In the absorbable group, patients were treated with the implants (n = 76). The metal group included patients treated with titanium or steel screws (n = 52). The extremities were placed in a cast for six weeks after surgery and were utilized for another 6-8 weeks. Patients were followed up for 12-30 months and were evaluated accordingly. The authors examined several aspects such as age, gender, open or closed repair, mechanism of injury, length of hospitalization, type of fracture, time of recovery, and complications. There were no statistically significant differences between the groups regarding demographic qualities, such as age, type of fracture, side of injury, and length of cast application (p > 0.05 in all cases). Out of 76 patients in the PLGA group, only two presented with complications, so reoperation took place. The rest healed without complications or refractures. Two of those treated with metal screws (n = 52) had minor, and four had major complications with reoperation. In pediatric cases, PLGA implants may present excellent results for treating ankle fractures. They do not disturb the growth plate and do not require reoperation. For this reason, they reduce the burden on the patient and the healthcare provider while simultaneously decreasing the risk of complications, such as infections or problems due to general anesthesia.

Bilateral multiple ribs and sternum fracture causing central flail chest with respiratory failure

Bilateral thoracic blunt injuries in a patient may present with central Flail chest, and acute respiratory failure which is one of the life-threatening complications. We present a case of central flail chest caused by blunt trauma, successfully managed with operative rib and sternum fixation. A 35-year male with a central flail chest with acute respiratory failure caused by road-traffic accident who was managed initially with bilateral intercostal chest-tube drainage for significant bilateral hemopneumothorax and lung contusions. The patient was intubated and connected to mechanical ventilatory support with positive pressure ventilation for the internal pneumatic stabilization. There were multiple rib fractures anteriorly (first to seventh rib bilaterally) and fracture of the sternum - the flail chest, for which he underwent bilateral rib fixation and fixation of sternum with titanium reconstruction plate and screws on the 9th postinjury day. Tracheostomy was done along with fixation in the same sitting. Post-operatively, after 48 hours of positive pressure mechanical ventilation, the weaning was started and by the 4-5th day, the patient was on room air with a tracheostomy tube. The patient recovered uneventfully and was discharged on the eighth postoperative day.

Effect of different agents on preload force of dental implants with bio high-performance poly-ether-ether-ketone abutments

PurposeThis study evaluated the influence of different agents such as blood, artificial saliva, and normal saline on preload force of dental implants with bio-high-performance poly-ether-ether-ketone (Bio-HPP) abutments to determine its effect on screw loosening. MethodsForty (N = 40) Grade 5 titanium dental implant analog (GM Implant Analog; Neodent, Straumann) with Bio-HPP poly ether-ether ketone (PEEK) abutment and titanium screw was used in the study. The samples were embedded in acrylic split mold. In the control Group C, no agent was added. In the other three groups, blood (B), normal saline (N) and saliva (S) was added in the access cavity of the samples. A sequential torque of 15 Ncm, 20 Ncm, 25 Ncm, 30 Ncm up to 35 Ncm was applied with a digital torque meter (Eclatorq, model: SD-05bn, range:2.5–50 Ncm, torque accuracy: ± 2%cw). Samples were subjected to thermomechanical cyclic loading at 5–550 Celsius for 1000 cycles (Chewing simulator, CS 4.4) to simulate six months of clinical service. Preload was measured as reverse torque value (RTV). Raw data in the form of mean ± standard deviation was documented and subjected to statistical analysis. A one-way ANOVA was performed to contrast the groups. Tukey HSD test was used to determine the multiple comparison assessment (P < 0. 05). ResultsA mean reverse torque value of 35 Ncm ±0.00 was observed in both control and in groups exposed to normal saline (P >.05). Measurements of 33.4 Ncm ±2.51 and 34.8 Ncm ±0.40 were found when exposed to blood and artificial saliva in order (P < .05). When compared with control, exposure to blood showed significant variation in preload (P = .03). ConclusionA significant reduction in reverse torque force was observed when titanium implants and Bio-HPP abutments were exposed to blood, suggesting a potential risk of screw loosening (P < .05). In contrast, minimal decrease and no significant change in preload were noted with exposure to saliva and normal saline (P > .05).

Improved metal suppression using new generation low-field MRI: a biophantom feasibility study.

Novel 0.55 MRI scanners have the potential to reduce metal artifacts around orthopedic implants. The purpose of this study was to compare metal artifact size and depiction of anatomy between 0.55T and 3.0T MRI in a biophantom. Steel and titanium screws were implanted in 12 porcine knee specimens and imaging at 0.55T and 3T MRI was performed using the following sequences: turbo spin-echo (TSE), TSE with view angle tilting (VAT), and slice encoding for metal artifact correction (SEMAC) with proton-density (PD) and T2-weighted short-tau inversion-recovery (T2w-STIR) contrasts. Artifacts were measured, and visualization of anatomy (cartilage, bone, growth plates, cruciate ligaments) was assessed and compared between groups. Metal artifacts were significantly smaller at 0.55T. The smallest artifact sizes were achieved with SEMAC at 0.55T for both PD and T2w-STIR sequences; corresponding relative size reductions vs. 3.0T were 78.7% and 79.4% (stainless steel) and 45.3% and 1.4% (titanium). Depiction of anatomical structures was superior at 0.55T. Substantial reduction of artifact size resulting in superior depiction of anatomical structures is possible on novel 0.55T MRI systems. Further clinical studies are required to elucidate patient-relevant advantages.

Assessment of biomechanical strength of titanium versus unsintered-hydroxyapatite/poly-L-lactic acid (u-HA/PLLA) osteosynthesis screws in bilateral sagittal split ramus osteotomy

Titanium osteosynthesis is considered to be stable for the bilateral sagittal split ramus osteotomy (BSSRO) procedure in orthognathic surgery but is disregarded owing to a multitude of complications, the most significant necessitating a secondary surgery for removal. Bioresorbable osteofixation devices, especially third-generation unsintered-hydroxyapatite/poly-L-lactic acid (u-HA/PLLA), are increasingly used in the mandibular region because of their strength and bioactive/osteoconductivity. To date, three titanium bicortical screws has been the standard for the rigid fixation of BSSRO. As data on the use of u-HA/PLLA bicortical screws are limited, we conducted an in vitro biomechanical strength test to evaluate the performance of 12-mm bicortical u-HA/PLLA screws in comparison with titanium screws using mandibular bone models. BSSRO was performed on all specimens, followed by fixation with either three titanium screws or three, four, or five u-HA/PLLA screws, and loading was performed using a clinically presumed occlusal force. Displacement forces (measured in newton ‘N’) of 50N, 130N, and 220N were applied. Our results showed that the use of three u-HA/PLLA screws was unstable, that of four u-HA/PLLA screws was comparable, and that of five u-HA/PLLA screws provided stability equal to that of the three titanium bicortical screws. Although further clinical assessment is needed, our study demonstrated that the five u-HA/PLLA bicortical screws are viable alternatives to titanium in BSSRO osteofixation.

Nonmetallic Carbon Fiber-Reinforced Polyetheretherketone Implants Vs Titanium Implants: Analysis of Clinical Outcomes and Influence on Postoperative Radiotherapy Planning in Metastatic Spine Tumor Surgery.

Titanium has been the conventional implant material of choice for fixation in both primary and metastatic spine tumor surgeries (MSTS). However, these implants result in artifact generation during postoperative computed tomography or magnetic resonance imaging, resulting in poor planning of radiotherapy (RT) and suboptimal tumor surveillance. Carbon fiber-reinforced polyetheretherketone (CFR-PEEK) implants have gained momentum for instrumentation in MSTS due to their radiolucent properties. In this study, the perioperative outcomes, postoperative imaging artifacts, and dosimetric data of CFR-PEEK implants to titanium implants were compared to assess for potential benefits in postoperative RT planning in patients undergoing MSTS. This is a retrospective study involving 62 patients who underwent operations for MSTS. The cohort of CFR-PEEK fixations (n = 20) was compared with a series of patients operated using titanium implants (n = 42). Patient-related data, including demographics, tumor pathology and extent of morbidity, intraoperative data, functional outcome, and RT-related data, were recorded for both groups. Primary outcome measures for RT data were amount of artifact generated on postoperative imaging and the time taken to contour them. All patients were followed up postoperatively for a minimum of 2 years or until death, whichever was earlier. Both groups had similar clinical outcomes for pain and overall survival predictability preoperatively (P = 0.786). The mean number of levels instrumented by titanium screws was 5.69 ± 2.64, while for CFR-PEEK screws it was 4.26 ± 1.05. Mean volume of artifact generated during postoperative computed tomography was 73.4 ± 50.43 mm3 in the titanium group and 20.0 ± 20.7 mm3 in the CFR-PEEK group (P < 0.001). The mean time taken to contour the artifacts was 17.3 ± 5.84 minutes in titanium group and 9.60 ± 7.17 minutes in CFR-PEEK group (P = 0.049). Our study confirms that CFR-PEEK screws significantly reduce artifact generation and the time taken to contour them during postoperative RT planning while delivering equivalent clinical and functional outcomes as compared with standard titanium implants.

Experimental and Histological Validation of Nanostructured Products Use in Maxillofacial Surgery

The aim of the study is using experimental histological techniques to validate the beneficial potential of specific medical devices made of nanostructured titanium, and compare their effect with factorymade products currently applied in maxillofacial surgery. Material and methods. The study involved 50 sexually mature male Chinchilla rabbits. An open fracture of the lower jaw was simulated in the animals. In the 1st series of the experiment, the fragments were fixed using nanostructured miniplates and miniscrews made of Grade 4 titanium. In the 2nd series, they were fixed with standard miniplates and miniscrews from Konmet LLC. The material for the study was taken on the 7th, 14th, 21st, 28th and 40th days after the operation. In all series the object of the study was the extirpated lower jaw in the fracture area. The prepared histological sections were stained with Mayer's hematoxylin and eosin. The immunohistochemistry technique was used to identify cells with signs of proliferation (synthesizing the Ki67 protein), to assess the expression of the synthesis of proteins p53, caspasa 3 and the anti-apoptotic protein bcl-2. The surfaces of titanium structures were studied by scanning electron microscopy. The results were processed statistically. Results. The study investigated the effect of miniplates and miniscrews made of nanostructured and standard titanium on rabbits. The data obtained revealed the nature of the proliferative and apoptotic potentials of osteoblasts in the regenerate, and also indicated an increase in the ratio of the number of cambial cells and cells with an apoptotic dominant in the zone contacting with the nanostructured surface of the titanium screw compared to the titanium screw manufactured by Konmet LLC. Taken together, the obtained data indicate that the use of nanostructured titanium Grade 4 for the production of miniplates and miniscrews has an optimizing effect on reparative osteogenesis. The mechanism of this effect is determined by the presence of osseointegration properties of titanium. Conclusion. Nanostructured titanium is advisable to use for the production of implants, reconstructive titanium plates and other products for bone grafting.

Two versus three magnesium screws for osteosynthesis of mandibular condylar head fractures: a finite element analysis

ObjectivesPrevious finite element analyses (FEA) have shown promising results for using two titanium screws in treating mandibular condylar head fractures but limited mechanical stability of a two-screw osteosynthesis with magnesium screws. Given the potential benefits of magnesium screws in terms of biocompatibility and resorption, this study aimed to compare two- and three-screw osteosynthesis solutions for a right condylar head fracture (AO CMF type p) with magnesium screws with a FEA.Materials and methodsA previously validated finite element model simulating a 350 N bite on the contralateral molars was used to analyze von Mises stress within the screws, fragment deformation, and fracture displacement. All screws were modeled with uniform geometric specifications mirroring the design of Medartis MODUS® Mandible Hexadrive cortical screws.ResultsThe three-screw configuration demonstrated lower values for all three parameters compared to the two-screw scenario. There was a 30% reduction in maximum von Mises stress for the top screw and a 46% reduction for the bottom screw.ConclusionsFracture treatment with three magnesium screws could be a valuable and sufficiently stable alternative to the established treatment with titanium screws. Further studies on screw geometry could help improve material stability under mechanical loading, enhancing the performance of magnesium screws in clinical applications.Clinical relevanceThe use of magnesium screws for osteosynthesis of mandibular condylar head fractures offers the benefit of reducing the need for second surgery for hardware removal. Clinical data is needed to determine whether the advantages of resorbable screw materials outweigh potential drawbacks in condylar head fracture treatment.

Finite element analysis of anatomic plate fixation for proximal clavicular fractures

To explore establishment and finite element analysis of personalized proximal clavicular anatomical plate screw fixation model. A 40-year-old male healthy volunteer was selected and the finite element analysis modules of 3D reconstruction software Mimics 15.01, Hypermesh 2019 and Abaqus 2020 were used. The finite element model of anatomic plate at the proximal clavicle was established, and a vertical load of 250 N was applied to the distal end of long axis of clavicle about 15 mm, then the overall structure, plate and screw displacement cloud image, Mises stress distribution were observed. The displacement distribution of the overall structure shows the maximum displacement was distributed on the distal clavicle. Under the four conditions of normal upper limb weight, longitudinal clavicle fracture, oblique fracture and shoulder impact violence during fall, longitudinal clavicle fracture and oblique fracture, the maximum displacement were 1.04 mm, 1.03 mm, 1.35 mm and 1.33 mm, respectively. The displacement cloud map of titanium alloy steel plate showed the largest displacement was distributed near the distal clavicular bone, and the maximum displacement were 0.89 mm, 0.88 mm, 1.10 mm and 1.09 mm, respectively. The displacement cloud map of titanium alloy screw showed the largest displacement was distributed at the root of the distal screw, and the maximum displacement were 0.88 mm, 0.87 mm, 1.08 mm and 1.06 mm, respectively. Mises stress distribution showed the maximum stress was mainly distributed on titanium alloy plates and screws, and the stress on the clavicle was very small. Mises stress distribution cloud showed the maximum Mises stress was distributed at the second row of screw holes near the clavicle, and the maximum Mises stress were 673.1, 678.1, 648.5, 654.4 MPa, respectively. The maximum stresses of titanium alloy screws were 414.5, 417.4, 415.8 and 419.7 MPa, respectively. The biomechanical changes of personalized proximal clavicular anatomical plates are demonstrated by using 3D finite element method to provide biomechanical data for personalized proximal clavicular anatomical plates.

Allograft Screws as Fixation of the Scarf Osteotomy.

Background: In comparison to titanium screws, novel cortical bone allograft screws may come with advantages in osseointegration and with avoidance of potential material removal surgery after scarf osteotomy. Methods: A scarf osteotomy with allograft bone screws as fixation was performed in 21 patients (30 feet). Clinical and radiological parameters were prospectively collected until one year after surgery. A retrospective control group, consisting of 75 patients (82 feet) after scarf osteotomy using headless compression screws, was used to compare clinical outcomes. Results: After fixation with allograft bone screws, the mean preoperative AOFAS score increased from 51.5 points preoperatively to 93.5 points one year after surgery. In radiological assessments, a continuous osseointegration with the remodeling of the bone screw was observed in all patients that finished follow-up. However, four metatarsal fractures occurred early postoperatively after fixation using allograft bone screws. There were only three material removal surgeries in patients treated with headless compression screws. Conclusions: Allograft bone screws display a safe fixation and are a biological alternative for scarf osteotomy. Enough distance between the screw and the proximal osteotomy should be ensured to avoid fractures.

Osseointegration potential of boron-coated titanium alloy pedicle screw in rabbit spine model

BackgroundSpinal implants’ longevity is crucial, but titanium alloys, while advantageous, lack strong bone integration. This study aimed to achieve better osseointegration rates by utilizing the ability of boron compounds to transform stem cells in the vertebra into osteoblasts.MethodTwenty male albino rabbits were divided into control (n = 10) and experimental (n = 10) groups. Control group received titanium alloy pedicle screws, while experimental group received boron-coated titanium alloy screws. Under general anesthesia, screws were inserted into the L6 and L7 lumbar spines. After 16 weeks, all animals were euthanized for histological examination. Vertebra samples underwent decalcification and H&E staining. Microscopic examination assessed osseointegration, necrosis, fibrosis, and vascularization using a triple scoring system by two blinded observers.ResultIn the boron-coated titanium alloy group, all subjects exhibited osseointegration, with 50% showing focal, 40% moderate, and 10% complete osseointegration. In the titanium alloy group, 90% showed osseointegration (70% focal, 10% moderate, and 10% complete).The differences between the groups were not statistically significant (p = 0.302). Focal necrosis rates were similar between groups, with 50.0% in the titanium alloy and 60.0% in the boron-coated group (p = 0.653).Fibrosis was absent in the titanium alloy group but present in the boron-coated group, albeit with lower rates of focal fibrosis (20.0%). However, the difference was not statistically significant (p = 0.086).Vascularization patterns showed no significant difference between groups.ConclusionBoron-coated titanium alloy pedicle screws provided osseointegration rates comparable to standard titanium screws and exhibited acceptable levels of necrosis and fibrosis. With stronger biomechanical properties, they could be a better alternative to currently used titanium screws.

The Effect of Gold Nanoparticles and Apricot Kernel Extract on the Osseointegration of Dental Implants - A Rabbit Model

Introduction The osseointegration of dental implants is critical to their longevity and success. Various factors such as surface modifications, both additive and subtractive, systemic drug administration, growth factors, and plasma derivatives can influence osseointegration. Aims and Objectives This study aimed to study the effects of gold nanoparticles and aqueous extract of apricot kernels on the osseointegration of titanium implants in the tibia of rabbits. Materials and Methods Apricot kernels were dried, grounded, and dissolved in water to obtain an aqueous extract. It was filtered and stored in the refrigerator at 4oC. Gold nanoparticles (AuNPs) were prepared by mixing 3 ml of 0.02 mM hydrogen tetrachloroaurate with 1 ml of olive leaf extract. The mixture was stirred vigorously for 15 minutes on a heater stirrer at 50oC. Titanium screw implants were sterilized in an autoclave at 120oC with 15 pounds per square inch for 30 minutes. Sterilized implants were stored in sealed containers until use. The study was carried out at the College of Veterinary Medicine, University of Mosul, Iraq. The ethical approval for the study was obtained from the institutional animal care and use committee, College of Veterinary Medicine, University of Mosul, Mosul, Iraq, on 15/04/2023 on reference no UM.VET.2023.013. Nine healthy male adult white New Zealand rabbits aged between 10-12 months were utilized for the study. Three pure titanium implants, each of a type, were placed in each tibia. The implants were categorized as follows: control group (18 uncoated implants) and experimental group (36 coated implants). The implant placement was divided into three groups: controls with uncoated implants (n=18), AuNPs-coated implants (n=18), and apricot kernel extract-coated implants (n=18). General anesthesia was induced by intramuscular injection of ketamine hydrochloride 50mg (1ml /kg of body weight) plus xylazine 2% (0.2 ml /kg of body weight). The AuNPs-coated implants were implanted in the superior osteotomy site in the tibia. The apricot kernel extract-coated implants were implanted in the inferior osteotomy site and the uncoated implants were implanted in the middle osteotomy sites. Histological and histomorphometric tests were performed on all bone implant blocks at one-week, two-week, and three-week intervals after implant placement. The results were evaluated based on the amount of bone formation, cellular components, and inflammation. Tabulated data were statistically analyzed using SPSS v23.0 (IBM, Armonk, NY) using ANOVA with a statistical significance of p &lt;0.05 Results We observed a significant amount of osteogenesis with reduced inflammation in AuNPs-coated implants and apricot kernel extract-coated implants compared to untreated implants. The osteoclastic activity was significantly higher in untreated implants than the treated implant sites. A statistically significant association was observed between coated implants and untreated implants. Conclusion The application of gold nanoparticles and aqueous extract of apricot kernels appears to be promising in reducing inflammation and improving bone apposition on the titanium implant surface. However, this preliminary investigation warrants further research.

How difficult is titanium plate and screw implant removal? A retrospective case series

IntroductionTitanium implants are commonly used for surgical fixation in orthopedic trauma, and have many benefits compared to stainless steel implants. Despite these benefits, some orthopedic surgeons remain hesitant to use titanium implants due to concerns of difficulty with future implant removal, given concerns with cold-welding and screw strippage. The objective of this study was to assess difficulties associated with titanium plate and screw implant removal. MethodsThis is a retrospective case series from a large hospital system. Patients were identified using Current Procedural Terminology (CPT) code 20,680 from 2017 to 2020. Patients were included if they had removal of titanium plate and screws from the upper or lower extremity, were at least18 years of age, and considered skeletally mature. The ease of titanium plate/screw removal was determined by assessing for implant cold-welding, broken screws, stripped screws, and the need for advanced tools (screw removal set, trephine, burr). Results157 patients were identified, with a mean age of 54 years and 59 % female. In total 1274 screws were removed: 14 (1.1 %) were stripped, 8 (0.6 %) were cold-welded, 42 (3.3 %) were loose, and 13 (1.0 %) were broken. 183 plates were removed in total, and 15 (8.2 %) had bone overgrowth that required removal. 12 (7.6 %) procedures were complicated and required the use of advanced tools. Complicated implant removal operations occurred after significantly longer in vivo implant time (mean of 3.7 vs. 1.1 years, p = 0.036), were associated with a younger age, were more likely to occur in lower extremity procedures (p = 0.034), and took significantly longer time for removal (95 vs. 42 min, p < 0.001). ConclusionsDespite concerns with titanium implants, we found a low rate of screw strippage, breakage, and cold welding during the removal process. However, 7.6 % of the 157 surgeries required additional tools other than just a screwdriver, and needed additional operative time. This information allows treating surgeons to plan for implant removal when titanium implants have been used for fixation. Level of evidenceIV

Evaluation of Surface Morphology and Stress Distribution of Orthodontic Mini-implants in Maxilla: A Three-dimensional Finite Element Study

Objectives: Inaccurate design, insertion or loading of mini-implant may lead to disturbed bone turnover and subsequent implant failure. This study assesses the two commonly used types of implants and their bone stress pattern and determines which type of implant may be more patient-compatible. Method: The samples were categorized into four groups and analyzed by scanning electron microscopy to assess the surface morphology. Stress distribution was estimated using finite element method for which three-dimensional (3D) models of the maxilla and mini-screws were prepared. The implant was then inserted 5 mm from the alveolar crest onto the buccal cortical plate of maxilla between the second premolar and first molar within the platform of Ansys Workbench software. Two loads were applied: 5 Ncm and 2 N. Evaluation of von Mises stresses in the bone was estimated. Results: The study concluded that tapered stainless steel screws exerted greater stress on the bone than titanium screws in both situations. As the diameter increased from 1.3 mm to 1.5 mm, the mini-screw displacement and stress were less. Under 2 N force, the stress was distributed around the head and neck of the mini-implant and the cortical bone. Conclusion: The assessment of von Mises stress distributed around an orthodontic mini-implant under a constant load revealed that stainless steel mini-screws generated more stress than titanium mini-screws. It was observed that the majority of the stress and strain is tolerated by the cortical bone, not the cancellous bone. The diameter of mini-screw is more significant irrespective of material composition.

Clinical and Micro-CT analyses of Vertical Guided Bone Regeneration of Mandible using a d-PTFE Membrane, Autogenous Bone, and High-Temperature Processed Xenograft- A Case Series Study.

Purpose: To evaluate the efficacy of vertical guided bone regeneration (GBR) in the mandible utilizing a non-resorbable membrane and a bone graft combination of autogenous bone chips, and high-temperature processed (HTP) xenograft, through CT scans and microCT analysis. Materials and Methods: Patients underwent vertical ridge augmentation procedures prior to implant placement. The surgical procedure included flap elevation and placement of a bone graft comprising a 1:1 combination of autogenous posterior mandible-derived bone chips, and HTP xenograft graft particles covered with a d-PTFE membrane trimmed to suit the 3D shape of the bone defect. This was fastened securely with titanium screws and pins, and a layer of native collagen membrane. Post-operative complications and ridge measurements were assessed. Pre bone augmentation and pre implant placement bone parameters were obtained from CT scans. Biopsy specimens collected during implantation were examined by microCT. Results: All 13 study procedures were successful without any complications. The results revealed average vertical and horizontal bone gains of 3.35 mm and 5.15 mm respectively. A total of 33 implants were successfully placed in the augmented areas, without the need for further bone augmentation. MicroCT analysis revealed 48% bone, 15% filler material, and 37% non-calcified tissue in the augmented region compared to 65% bone, 3% filler material, and 32% non-calcified tissue in the pristine bone. Conclusions: A mixture of autogenous bone and HTP xenograft, covered with a d-PTFE membrane and a layer of native collagen membrane is effective for vertical GBR.

Effect of Titanium Base Abutment Height and Restorative Material on Torque Maintenance of Hybrid-abutment Restoration with Offset Implant Placement.

The purpose of this in vitro study was to evaluate the effect of titanium base height on torque loss of monolithic zirconia, lithium disilicate, and polymer-infiltrated ceramic hybrid- abutment restorations for offset placed implant. Forty-two hybrid- abutment restorations supported by offset placed implants (diameter: 4.2 mm; length: 10 mm) were divided into 6 groups: short titanium base and zirconia (SZ), long titanium base and zirconia (LZ), short titanium base and lithium disilicate (SE), long titanium base and lithium disilicate (LE), short titanium base and polymer-infiltrated ceramic (SP), and long titanium base and polymer-infiltrated ceramic (LP). An adhesive resin cement was used to bond the restoration to the titanium base. The restoration was secured with titanium screw tightened to 30 Ncm by using a calibrated torque meter device. The specimens were exposed to thermocycling (5000 cycles at 5°C to 55°C), then cyclic loaded (120 000 cycles/50 N/1.6 Hz), where the load was placed vertically in mesial fossa of the restoration. After the loosening torque value of the abutment screw was measured by the torque meter device, the torque loss and its percentage were calculated. Two-way ANOVA, one-way ANOVA, and post hoc Tukey tests were used for statistical analysis of the data (α&#61;.05). The 2-way ANOVA test showed significant differences in loosening torque, torque loss and percentage of torque loss across the restorative material (P<.001), no significant difference across the height of titanium base (P&#61;.213) and no significant interaction (P&#61;.845) between restorative material and height of titanium base. Regarding the restoration type, 1-way ANOVA test showed significant difference (F ratio&#61;15.95, P<.001) in torque loss between groups. The mean torque loss value with monolithic zirconia was significantly higher than with lithium disilicate (P&#61;.039) and polymer-infiltrated ceramic (P<.001), respectively. Between the lithium disilicate and polymer-infiltrated ceramic, a significant difference (P&#61;.013) was also found. The restorative material had a major effect on the torque maintenance in hybrid-abutment-restoration supported by offset placed implant, while the titanium base abutment height had no influence on it. Compared to lithium disilicate and polymer-infiltrated ceramic materials, monolithic zirconia induced higher torque loss when used as hybrid-abutment-restoration.

Surgical Premaxilla Reposition and Secondary Bone Grafting in a Children with Complete Bilateral Trans-Foramen Cleft Lip and Palate: a Case Report

The objective of this study is to report the clinical case of a child with complete bilateral trans-foramen CLP who underwent surgical repositioning of the premaxilla with internal rigid fixation and a secondary bone grafting. The boy was following by different specialists since five days of life, being subjected to the entire surgical protocol to close the lip and palate. At 9 years old it was proposed surgical premaxilla reposition and, in a second surgery, a bone grafting in the alveolar process. After a virtual planning, surgery was performed under general anesthesia. The access was performed maintaining the vestibular pedicle of premaxilla, and after remove the interferences at the vomer and maxilla, premaxilla was fixed with titanium plates and screws. Six months after, fixation material was removed and the remaining gaps were grafted with iliac bone. After 21 months of the first surgery, the patient presents a good anteroposterior positioning of the maxilla and lip seal and, those responsible for the patient, reported an improvement in the patient's quality of life, with improvements mainly in speech, chewing and the patient's social life.

Risk of thromboembolism after intraosseous implantation of metallic devices with extracellular vesicles derived from multipotent stromal cells: preliminary results

Background. New implantation methods are of great importance due to the development of endoprostheses in traumatology and orthopedics, restorative medicine and dentistry. Equally important is the early detection and description of the implant-associated complications. The aim of the study is to find and describe thrombi and emboli in the heart and lungs formed after experimental implantation of metallic devices in the peripheral part of limb using extracellular vesicles of mesenchymal stromal cells. Methods. Outbred rabbits of both genders at the age from 4 to 6 months and of weight from 3 to 4 kg underwent experimental implantation. The study enrolled 57 species in total. They were divided into two groups: 30 animals underwent implantation of metallic devices using extracellular vesicles of mesenchymal stromal cells (EV MSCs), 27 — without their use. The rabbits’ hearts and lungs were studied by light microscopy methods at different stages after integration of screw titanium implants into the proximal condyle of the tibia using EV MSCs. Results. After implantation of metallic devices into the proximal condyle of the tibia, we detected fibrin, detritus and even the red bone marrow structures (various blast forms of hematopoietic cells: megakaryocytes, cells of the erythroid and myeloid lineages) in the right cavities of the heart. In the pulmonary arteries, we also found thrombi and emboli, which either led to the obliteration of the involved vessel or to gradual lysis, not disappearing completely within 10 days of follow-up. Conclusions. After intraosseous implantation of the metallic devices, there is an embolism risk in the right atria and ventricle of the heart and the pulmonary arteries and veins due to the debris migration with the bloodstream from the surgery site. At the same time, one cannot exclude a thrombotic risk in the heart and pulmonary arteries as a reaction to the presence of detritus. It is advisable to take measures aimed at preventing both debris releasing into the bloodstream and pulmonary embolism during any implantations into the bone tissues, even of relatively small devices. Using EV MSCs to affect the implant engraftment processes has no significant effect on the severity and frequency of thromboembolic complications.