Search Results (169)

A novel macrodesign for a dental implant characterized by a non-monotonic variation in core diameter and thread shape has been described to produce lower stress levels during insertion as compared to conventional tapered implants. Two finite element models resembling the lower left molar region with preformed osteotomies were created based on a cone beam computed tomography (CBCT) scan. Insertion of both the novel and the conventional, tapered implant type were simulated using Standard for the Exchange of Product model data (STEP) files of both implant types. Von Mises equivalent stress, strain development, and amount of redistributed bone were recorded. The conventional implant demonstrated a continuous increase in strain values and reaction moment throughout the insertion process, with a brief decrease observed during the final stages. Stress levels in the cortical bone gradually increased, followed by a reduction when the implant was finally positioned subcrestally. The novel implant achieved the maximum magnitude of reaction moment and cortical bone strain values when the implant’s maximum core diameter passed the cortical bone layer at around 60% of the insertion process. Following a notable decrease, both the reaction moment and stress started to rise again as the implant penetrated further. The novel implant removed more bones in the trabecular region while the conventional implant predominantly interacted with cortical bone. Overall, the novel design seems to be less traumatic to alveolar bone during the insertion process and hence may lead to reduced levels of initial peri-implant bone loss. Full article

Background: Surgical neck nonunions of the proximal humerus present a complex clinical challenge, especially in elderly patients with pre-existing glenohumeral arthritis. Reverse total shoulder arthroplasty (RTSA) offers a reliable treatment option in these cases; however, resection of the tuberosities may compromise joint stability, increase the risk of postoperative dislocation and compromise postoperative function. This article describes a reproducible RTSA technique that preserves and repairs the greater and lesser tuberosities, aiming to enhance construct stability and optimize outcomes. Methods: We present a 74-year-old female with underlying glenohumeral arthritis who underwent RTSA for a symptomatic surgical neck nonunion via an extended deltopectoral approach. The nonunion is first mobilized, and tuberosity osteotomies are performed. After implant placement, the tuberosities are secured to the implant, to each other, and to the humeral shaft. A cerclage suture is also passed circumferentially to reinforce the repair and prevent posterior gapping. Results: The patient regained her pre-injury level of function by her last follow-up. She had pain-free, active forward elevation to 110 degrees and radiographic evidence of maintained tuberosity reduction and healing. There was no evidence of instability. Conclusions: In conclusion, incorporating tuberosity preservation and repair into RTSA for proximal humerus nonunion may reduce dislocation risk and improve functional recovery in elderly, low-demand patients. Full article

A novel composite patch osteosynthesis technique (CPT) has demonstrated promising ex vivo biomechanical performance in small tubular bones. To bridge the gap toward clinical evaluations, this study compared the stability of the CPT to a stainless-steel locking plate (LP) in an experimental in vivo ovine bilateral proximal phalanx fracture model. Eight sheep underwent a midline osteotomy with a 4.5 mm circular unicortical defect in the lateral proximal phalanx of both front limbs, treated with the CPT (n = 8) or the LP (n = 8). A half-limb walking cast, or a custom off-loading hoof shoe, was used for postoperative protection. Implant stability was assessed by post-surgery X-ray evaluations and post-euthanasia (16 weeks) dual-energy X-ray absorptiometry (DXA). At week one, all CPT implants demonstrated mechanical failure, while all LPs remained overall intact. Mean BMD was 0.45 g/cm² for CPT and 0.60 g/cm² for LP in the fracture area (p = 0.078), and 0.37 g/cm² vs. 0.41 g/cm² in the distal epiphysis (p = 0.016), respectively. In conclusion, the CPT demonstrated indications of inferior stability compared to the LP in this fracture model, which may limit its clinical applicability in weight-bearing or high-load scenarios and in non-compliant patients. Full article

Introduction: This manuscript addresses the limitations of traditional orthognathic surgery in achieving both functional and aesthetic correction in patients with Class II malocclusion and severe mandibular retrusion. Current techniques often struggle to simultaneously address mandibular deficiency and inadequate transverse dimension, leading to unsatisfactory outcomes. Methods: Seven male patients underwent bimaxillary osteotomy with mandibular advancement. A novel surgical plate, Implate, was used, which was designed to facilitate precise osteotomy and stabilization. Pre-surgical planning included CBCT scanning, 3D modeling, and surgical simulation. Postoperative assessments included clinical examinations, CT and OPT scans. Results: Implate successfully addressed the challenges of conventional techniques, minimizing the formation of bony steps and achieving a more harmonious facial profile. The minimally invasive procedure, with careful periosteal and muscle management, contributed to stable outcomes, and no complications were reported. At the 6-month follow-up, OPT analysis showed a mean mandibular width increase of 18.1 ± 6.2 mm and vertical ramus height gains of 6.0 ± 3.1 mm (left) and 5.8 ± 1.7 mm (right). Conclusions: According to our preliminary experience, the integration of Implate into surgical practice offers a significant improvement in treating complex Class II malocclusions. By simultaneously correcting mandibular retrusion and width while minimizing complications, Implate provides a superior solution compared to traditional methods. This innovative approach highlights the potential of combining advanced surgical techniques with personalized 3D-printed implants to achieve optimal functional and aesthetic outcomes. Further prospective studies with controls and longer follow-up are needed to validate the efficacy and reproducibility of Implate in wider clinical use. Full article

Background/Objectives: Limb malalignment disrupts physiological joint forces and predisposes individuals to the development of osteoarthritis. Surgical interventions such as distal femur or high tibial osteotomy aim to restore mechanical balance on weight-bearing joints, thereby reducing long-term morbidity. Accurate alignment is crucial since it cannot be adjusted after stabilization with plates and screws. Recent advances in personalized medicine offer the opportunity to tailor surgical corrections to each patient’s unique anatomy and biomechanical profile. This study evaluates the benefits of 3D planning and patient-specific cutting guides over traditional 2D planning with standard implants for alignment correction procedures. Methods: We assessed limb alignment parameters pre- and postoperatively in patients with varus and valgus lower limb malalignment undergoing acute realignment surgery. The cohort included 23 opening-wedge high tibial osteotomies and 28 opening-wedge distal femur osteotomies. We compared the accuracy of postoperative alignment parameters between patients undergoing traditional 2D preoperative X-ray planning and those using 3D reconstructions of CT data. Outcome measures included mechanical axis deviation and tibiofemoral angles. Results: 3D reconstructions of computerized tomography data and patient-specific cutting guides significantly reduced the variation in postoperative limb alignment parameters relative to preoperative goals. In contrast, traditional 2D planning with standard non-custom implants resulted in higher deviations from the targeted alignment. Conclusions: Utilizing 3D CT reconstructions and patient-specific cutting guides enhances the accuracy of postoperative limb realignment compared to traditional 2D X-ray planning with standard non-custom implants. Patient-specific instrumentation and personalized approaches represent a key step toward precision orthopedic surgery, tailoring correction strategies to individual patient anatomy and potentially improving long-term joint health. This improvement may reduce the morbidity associated with lower limb malalignment and delay the onset of osteoarthritis. Level of Evidence: Therapeutic Level III. Full article

Background/Objectives: Guided implant surgery relies on the use of surgical templates to direct osteotomy drills, but guide design may influence irrigation efficiency, hence bone overheating, a critical factor in preventing thermal necrosis. This ex vivo study compared temperature changes when drilling using two guide designs: a closed-frame (occlusive structure) and an open-frame (non-occlusive design), evaluating their clinical relevance in mitigating overheating. Methods: Sixteen pig ribs were scanned, and implant osteotomies were planned via a guided surgery software. Two 3D-printed resin templates, one with a closed-frame design and one with an open-frame design, were tested (8 ribs per group, 24 implants per group). Drilling was performed sequentially (diameter of 1.9 mm, 3.25 mm, and 4.1 mm) at 800 rpm, while bone temperatures were recorded at depths of 3 mm and 10 mm using K-type thermo§s. Results: Significantly higher temperature rises were observed with the closed-frame guide. Drilling depth had also a significant influence, with higher temperatures at 3 mm than 10 mm (p < 0.001), suggesting that cortical bone density may amplify frictional heat. No significant effect of drill diameter was detected. Conclusions: Within the limitations of this ex vivo model, the open-frame design kept the maximal temperature rise about 0.67 °C lower than the closed-frame guide (1.22 °C vs. 0.55 °C), i.e., a 2.2-fold relative reduction was observed during the most demanding drilling step. This suggests a more efficient cooling capacity, especially in dense cortical bone, which offers a potential benefit for minimizing thermal risk in guided implant procedures. Full article

Objective: To assess the bone histological changes and histomorphometric parameters when using different implant site preparation methods. Methods: A systematic search was conducted in March 2025 across the PubMed, Scopus, and Web of Science (WoS) databases following the PRISMA guidelines. An initial search of the databases yielded 338 potentially relevant articles. Ultimately, a total of 29 articles were included in the qualitative synthesis in this review. The considerable heterogeneity among the included studies precluded a meta-analysis. Results: This systematic review showed that, among all the assessed implant site preparation methods, which were drilling, laser, piezoelectric surgery, osteotomy and osteodensification, the classical drilling method was more likely to cause adverse changes at the drill site, such as microcracks, uneven bone margins, osteocyte damage and thermal injury. In contrast, alternative methods resulted in fewer microcracks, minimal inflammation, a reduced risk of thermal tissue damage and denser, more regular bone formation. When using these methods, the %BIC parameter was higher than when using the drilling method. Conclusions: Using alternative techniques to prepare the implant bed creates favourable conditions for proper healing and osseointegration by eliminating defects resulting from the drilling method. However, it should be noted that satisfactory results can be achieved using the classical method if the correct parameters of the drill rotation, cooling and load are employed. Further studies based on a uniform methodology are necessary to determine the most efficient and safest parameters for each method. Full article

Background/Objectives: This review analyzes the effects of invasive and non-invasive methods of knee joint unloading on knee loading, employing a biomechanical model to evaluate their impact. Methods: PubMed, Web of Science, Cochrane, and Scopus were searched up to 15 May 2024 to identify eligible clinical studies evaluating Joint Space Width, Cartilage Thickness, the Western Ontario and McMaster Universities Osteoarthritis Index, the Knee Injury and Osteoarthritis Outcome Score system, Gait velocity, Peak Knee Adduction Moment, time to return to sports and to work, ground reaction force, and the visual analogue scale pain score. A second search was conducted to select a biomechanical model that could be parametrized, including the modifications that each treatment would impose on the knee joint and was capable of estimate joint loading to compare the effectiveness of each method. Results: Analyzing 28 studies (1652 participants), including 16 randomized clinical trials, revealed significant improvements mainly when performing knee joint distraction surgery, increasing Joint Space Width even after removal, and high tibial osteotomy, which realigns the knee but does not reduce loading. Implantable shock absorbers are also an attractive option as they partially unload the knee but require further investigation. Non-invasive methods improve biomechanical indicators of knee joint loading; however, they lack quantitative analysis of cartilage volume or Joint Space Width. Conclusions: Current evidence indicates a clear advantage in knee joint unloading methods, emphasizing the importance of adapted therapy. However, more extensive research, particularly using non-invasive approaches, is required to further understand the underlying knee joint loading mechanisms and advance the state of the art. Full article

Achieving the appropriate primary stability for immediate or early loading in areas with low-density bone, such as the posterior maxilla, is challenging. A three-dimensional (3D) stabilization implant design featuring a tapered body with continuous cutting flutes along the length of the external thread form, with a combination of curved and linear geometric surfaces on the thread’s crest, has the capacity to enhance early biomechanical and osseointegration outcomes compared to implants with traditional buttressed thread profiles. Commercially available implants with a buttress thread design (TP), and an experimental implant that incorporated the 3D stabilization trimmed-thread design (TP 3DS) were used in this study. Six osteotomies were surgically created in the ilium of adult sheep (N = 14). Osteotomy sites were randomized to receive either the TP or TP 3DS implant to reduce site bias. Subjects were allowed to heal for either 3 or 12 weeks (N = 7 sheep/time point), after which samples were collected en bloc (including the implants and surrounding bone) and implants were either subjected to bench-top biomechanical testing (e.g., lateral loading), histological/histomorphometric analysis, or nanoindentation testing. Both implant designs yielded high insertion torque (ITV ≥ 30 N⋅cm) and implant stability quotient (ISQ ≥ 70) values, indicative of high primary stability. Qualitative histomorphological analysis revealed that the TP 3DS group exhibited a continuous bone–implant interface along the threaded region, in contrast to the TP group at the early, 3-week, healing time point. Furthermore, TP 3DS’s cutting flutes along the entire length of the implant permitted the distribution of autologous bone chips within the healing chambers. Histological evaluation at 12 weeks revealed an increase in woven bone containing a greater presence of lacunae within the healing chambers in both groups, consistent with an intramembranous-like healing pattern and absence of bone dieback. The TP 3DS macrogeometry yielded a ~66% increase in average lateral load during pushout testing at baseline (T = 0 weeks, p = 0.036) and significantly higher bone-to-implant contact (BIC) values at 3 weeks post-implantation (p = 0.006), relative to the traditional TP implant. In a low-density (Type IV) bone model, the TP 3DS implant demonstrated improved performance compared to the conventional TP, as evidenced by an increase in baseline lateral loading capacity and increased BIC during the early stages of osseointegration. These findings indicate that the modified implant configuration of the TP 3DS facilitates more favorable biomechanical integration and may promote more rapid and stable bone anchorage under compromised bone quality conditions. Therefore, such improvements could have important clinical implications for the success and longevity of dental implants placed in regions with low bone density. Full article

Background/Objectives: The achievement of primary stability in low-density bone represents a critical endpoint in clinical practice. The aim of the present investigation was to evaluate the effectiveness of different drilling osteotomy techniques on polyurethane bone substitutes in vitro. Methods: A total of 320 osteotomies have been conducted on 10 pound per cubic feet (PCF) and 20PCF, respectively, with and without cortical layer. The simultaneous and progressive drilling protocol has been conducted at two different rotational speeds considering two different implant profiles (TAC conical vs. NT cylindrical implants). The study variables were insertion torque, removal torque, and resonance frequency analysis (RFA). Results: A significantly higher insertion torque, removal torque, and resonance frequency analysis RFA was detected at low speed with simultaneous drilling protocol (RPM) (p < 0.05). A TAC implant produced an increased implant stability compared to NT implants in all conditions tested (p < 0.05). Conclusions: The conical TAC implant showed higher implant stability in low-density polyurethane, and it is strongly recommended in critical bone quality. Simultaneous drilling osteotomy at low speed could further improve torquing positioning and significantly achieve primary stability in this condition. Full article

A tibial implant is necessary to provide mechanical support in open-wedge high tibial osteotomy (OWHTO) treatment of knee osteoarthritis. The pore structure and porosity of implants exert significant effect on tibia stress distribution and lower limb alignment stability. In this study, finite element (FE) analysis and in vitro biomechanical experiments were utilized to evaluate the impact of different tibial implants on postoperative tibial stress distribution. The biomechanical experimental results of experiments on tibial implants exhibit similar mechanical response patterns to the established finite element model, whose maximum displacement error is 1.18% under 1500 N compressive load. The hybrid porous implant developed in this study demonstrated significant stress reductions in both tibial bone (19.97% and 15.33% lower than mono-porous configurations at 73% porosity) and implant body (31.60% and 11.83% reductions, respectively), while exhibiting diminished micromotion tendencies. This consistent performance pattern was maintained across the entire porosity spectrum (53–83%) in implanted specimens. In summary, the finite element model established using authentic tibial CT data can effectively guide the structural design of tibial implants, and optimized pore structure design can provide enhanced mechanical support effects for tibial implants. Full article

It is widely recognized that excessive stress and/or strain can lead to peri-implant bone atrophy; therefore, the clinical success of dental implants is intrinsically related to their biomechanical behavior. This study evaluates the influence of the diameter, length, and material [Ti6Al4V (α+β Ti) and Ti35Nb7Zr5Ta (β-Ti)] of a novel cylindrical dental implant on stress and strain levels within maxillary bone of type II quality. The implant design aims to ensure an appropriate distribution of stresses and strains within the peri-implant bone structures (cortical and trabecular bones) while also facilitating surgical machining by requiring a simple, linear, and less expensive bone incision. This approach minimizes the risk of thermal necrosis, a common complication in osteotomies for conical implants that can lead to peri-implant bone loss. Using finite element analysis, stress and strain patterns were evaluated in the maxillary second premolar region under static delayed loading. The results reveal that the cortical bone strains remained below the critical threshold (0.003) to prevent resorption. In the trabecular bone, only larger diameter/length configurations satisfied the previous strain criterion. In all simulations, trabecular bone stress remained below 3 MPa, whereas cortical bone stress peaked at 78 MPa. Notably, the implant model with the largest diameter/length minimized stress and strain concentrations in type II bone when compared to smaller designs, thereby demonstrating its biomechanical advantage. Full article

Background: The autogenous bone core block (BCB) is a viable, biologically advantageous, and minimally invasive alternative to other augmentation procedures for small bone defects around dental implants. This study focused specifically on horizontal vestibular defects in the mandible, a frequently encountered yet underrepresented clinical situation, to evaluate the effectiveness and predictability of bone core grafting. Methods: Cylindrical autogenous bone cores, harvested from the implant-site osteotomy using trephine drills with a 2.5 internal diameter, were stabilized with osteosynthesis screws, and implants were placed simultaneously. Initial preoperative measurements of the edentulous ridge width were performed based on cone beam computer tomography (CBCT). At 4 months postoperatively, a subsequent CBCT measurement was performed for each implant site. Results: A total of 38 augmentation procedures were analyzed with a mean horizontal bone gain of 1.8 mm (p = 0.000). Improved outcomes were observed in V-shaped defects with remaining vertical bony walls, which contributed to better graft stability and volume preservation. While Khoury et al. previously validated the general applicability of this technique across various defect types, our study refines its indication by offering a clear protocol tailored to a common clinical niche. Conclusions: The proposed BCB method proved to be a safe, efficient, and with reduced morbidity procedure, providing clinicians with a practical and evidence-based tool for predictable horizontal bone augmentation. Full article

Background/Objectives: A novel 3D-printed, bioresorbable bone graft, made of nanohydroxyapatite (nHAP) covered by poly(lactide-co-glycolide) (PLGA), showed strongly expressed osteoinductive properties in our previous investigations. The current study examines its application in the dual regeneration of bone and cartilage by combining with nHAP gel obtained by nHAP enrichment with hydroxyethyl cellulose, sodium hyaluronate, and chondroitin sulfate. Methods: In the in vitro part of the study, the mitochondrial activity and osteogenic and chondrogenic differentiation of stem cells derived from apical papilla (SCAPs) in the presence of nHAP gel were investigated. For the in vivo part of the study, three rabbits underwent segmental osteotomies of the lateral condyle of the femur, and defects were filled by 3D-printed grafts customized to the defect geometry. Results: In vitro study revealed that nHAP gel displayed significant biocompatibility, substantially increasing mitochondrial activity and facilitating the osteogenic and chondrogenic differentiation of SCAPs. For the in vivo part of the study, after a 12-week healing period, partial resorption of the graft was observed, and lamellar bone tissue with Haversian systems was detected. Histological and stereological evaluations of the implanted grafts indicated successful bone regeneration, marked by the infiltration of new bone and cartilaginous tissue into the graft. The existence of osteocytes and increased vascularization indicated active osteogenesis. The hyaline cartilage near the graft showed numerous new chondrocytes and a significant layer of newly formed cartilage. Conclusions: This study demonstrated that tailored 3D-printed bone grafts could efficiently promote the healing of substantial bone defects and the formation of new cartilage without requiring supplementary biological factors, offering a feasible alternative for clinical bone repair applications. Full article

This study explored the complications and prognosis of modified tibial plateau leveling osteotomy with tibial tuberosity transposition (mTPLO-TTT) for simultaneously correcting high-grade medial patellar luxation (MPL) and cranial cruciate ligament disease (CCLD) in small-breed dogs. This retrospective study evaluated patient data, lameness scores, radiographic outcomes, and complications over a median follow-up period of 10 weeks. Additionally, an owner interview was conducted 6 months postoperatively. Nine stifles from seven dogs were included in this study. All cases showed satisfactory patellar alignment and stability after surgery, with no major complications or reluxations. The lameness scores improved, and radiographic assessments confirmed implant stability and appropriate bone healing. Owner-reported outcomes at 6 months were also favorable. These findings suggest that simultaneous mTPLO-TTT is an effective surgical option for small-breed dogs with concurrent CCLD and Grade IV MPL. Full article