Bone Plate Research Articles

Finite element model with realistic bone geometries for the optimal design of internal fixation during the fibula healing process.

A finite element model with realistic bone geometries is developed to design optimal internal fixation during the fibula healing process in this study. The effect of bone plate parameters on fibula fracture healing is studied. The relationship between differences in plate length, thickness and working length, and bone healing performance is focused. The optimal combination form of the bone plate parameters was selected by the orthogonal experimental design and fracture block strain to achieve bone healing maximize the performance. The model results show that the maximum equivalent force of the bone plate was below the material yield limit; the higher mean contact stresses in the bone fragments indicate that the bone plate is prone to higher contact stresses when they are long. The working length of the bone plate has a greater effect on callus healing than the thickness and length of the bone plate. The optimal internal fixation option for distal fibula fractures is achieved when it provides the stability required for internal fixation during bone healing. It ensures lower contact stresses in the fibula as well as maximum Young's modulus during callus healing process.

Clinical Application and Evaluation of Specialised Ring Fixators for the Management of Upper and Lower Limb Bone Fractures in Dogs

Present study was conducted on nine-clinical cases of humerus (n=4), femur (n=3) and radius-ulna (n=2) fractures in dogs of either sex, weighing 5.5 to 18 kg. Both closed (n=6) and open (n=3) fractures were treated in this study. The fracture was reduced and stabilized by transfixation using modified ring fixators. Semicircular (n=4) and hybrid fixators (n=5) were used for upper limb and lower limb bones respectively. The main component of fixator i.e. aluminium rings were designed locally at Bikaner using 4-mm aluminium sheets and fabricated accordingly. Full rings were used for distal radial (n=2) and distal femoral (n=1) fractures whereas semicircular rings were made through cutting the full ring during surgery for specific humeral (n=4) and femoral (n=2) fractures. Specialised wire fixation bolt (iron based; weighing 5.5g) was also designed locally at Bikaner for transcortical pin and ring articulation. Humeral and distal femoral fractures are challenging while bone plating of distal radial fracture demands further surgeries therefore external fixators were modified and applied in present study. Operated limbs were evaluated clinically with serial postoperative radiographs at regular intervals. Fixator-assembly evaluation and functional recovery of operated limbs were considered as objectives of this study.

Accessory tympanic plate ossicle: a new osteological entity.

The auricular cartilage, which is typically soft and flexible, can calcify or ossify because of diseases such as diabetes mellitus, trauma, radiation therapy for cancer, and more commonly from frostbite. Calcified, ossified, or hardened auricular cartilage is a rare finding in the clinical literature and appears to be absent in the physical and forensic anthropological literature. This study examines the ossified auricular cartilage and tests whether the hypothesis can be identified in postmortem skeletonized tissue and be part of the external auditory meatus. A total of 290 crania were examined for accessory ossicles. A descriptive and interpretative analysis was performed grossly, histologically, and morphometrically to document the morphology and location of the ossicles, investigate their structure, and perform hypothesis testing. Results revealed that seven females and one male crania from a total of 290 crania (2.76%) exhibit semi-ossified auricular cartilage attached to the tympanic plate of the temporal bone. The morphology and location of the ossicles at the junction of the auricle and external auditory meatus indicate they are hardened auricular cartilage that was verified with histological observations. Regression analysis indicates that addition of the ossicle to the depth of the auditory tube significantly changes coefficient of determination (R2) with respect to cranial breadth. In conclusion, results indicate that small cartilaginous structures of the external ear may ossify forming accessory tympanic plate ossicles that potentially could be identified in skeletal remains as a new osteological entity. This report highlights the types of information that can be gained using an approach that integrates forensic anthropology, gross anatomy, and histology.

Exploring Advanced Functionalities of Carbon Fiber-Graded PEEK Composites as Bone Fixation Plates Using Finite Element Analysis.

This study aims to address the challenges associated with conventional metallic bone fixation plates in biomechanical applications, such as stainless steel and titanium alloys, including stress shielding, allergic reactions, corrosion resistance, and interference with medical imaging. The use of materials with a low elastic modulus is regarded as an effective approach to overcome these problems. In this study, the impact of different types of chopped carbon fiber-reinforced polyether ether ketone (CCF/PEEK) functionally graded material (FGM) bone plates on stress shielding under static and instantaneous dynamic loading was explored using finite element analysis (FEA). The FGM bone plate models were established using ABAQUS and the user's subroutine USDFLD and VUSDFLD, and each model was established with an equivalent overall elastic modulus and distinctive distributions. The results revealed that all FGM bone plates exhibited lower stress shielding effects compared to metal bone plates. Particularly, the FGM plate with an elastic modulus gradually increased from the centre to both sides and provided maximum stress stimulation and the most uniform stress distribution within the fractured area. These findings offer crucial insights for designing implantable medical devices that possess enhanced mechanical adaptability.

Evaluation of the Effectiveness of Bone Grafting in Alveolar Ridge Augmentation Using the Two-Stage Splitting Technique.

Stimulation of neoosteogenesis is the main mechanism of osseointegration during installation of dental implants, bone tissue recession, and alveolar process augmentation in adentia. In experiments on miniature pigs, we used the technology of two-stage splitting of the ridge of the alveolar process of the mandible in combination with a xenograft that was placed between the fragments of the split bone plate. The morphology of the reparative process and the distribution of osteogenic differentiation markers in the compact and trabecular bone of the alveolar crest were studied. Signs of reparative osteogenesis were observed in the bone regenerate that had a lamellar structure, formed osteons, and foci of woven tissue. It was found that the xenograft was replaced by newly formed trabecular bone tissue. These sites were characterized by increased expression of osteocalcin and CD44. Augmentation technology through two-stage splitting provides trophic relationship of osteoprogenitor cells and is an effective method of osteogenesis stimulation in the alveolar process.

Is the facial bone wall critical to achieving esthetic outcomes in immediate implant placement with immediate restoration? A systematic review.

Rehabilitation in the anterior region requires specific conditions for success, such as the presence of papilla, emergence profile, and balance between pink and white esthetic. This systematic review aimed to evaluate the esthetic risk associated with immediate implant placement with immediate restoration in the anterior superior area, where the facial bone plate may be absent or deficient. The search was done in PubMed, Embase, Cochrane, Lilacs, Scopus, Scielo, and Google Scholar databases. The investigation involved clinical studies and observational studies published between January 2012 and July 2023. Studies were excluded if there was less than 12-month follow-up, no immediate restoration or facial defect, heavy smokers, or systemic disease. The risk of bias was assessed using the ROBINS-I and Modified-Cochrane RoB tools. Twelve studies were included in this systematic review. The thinner the facial plate, the higher the alveolus's risk of gingival recession or shrinkage. There was an increased interproximal recession when the thin phenotype was associated with flap surgery. An increase in pink esthetic score (PES) was reached when immediate implant placement (IIP) and immediate restoration were done. Soft tissue augmentation achieved more gingival-level stability. Regardless of the initial phenotype, an esthetic outcome was delivered. The risk of bias was high in 1 study and moderate in 3 studies. It is possible to conclude that esthetic results and increased final PES or patient satisfaction index in IIP treatments associated with immediate restoration could be obtained even in buccal bone wall defects or gingival recession, regardless of their extension.

THE POTENTIAL OF MAGNESIUM-BASED MICRO CYLINDER FOR CARTILAGE AND BONE REGENERATION UTILIZING AN IN VITRO OSTEOARTHRITIS MODEL

Osteoarthritis (OA) is an inflammatory disease affecting the complete synovial joint including the cartilage layer and the subchondral bone plate. Due to the multifactorial causes and the not yet completely resolved molecular mechanisms, it lacks a gold standard treatment to mitigate OA. Hence, biomaterials capable of delaying or preventing OA are a promising alternative or supplement to antiphlogistic and surgical interventions. Magnesium (Mg) and its alloys are among the promising biomaterials with osteoinductive effects. This work investigated the impact of Mg micro cylinders (length ≈of 1.0 mm and width of 0.5 mm) in vitro, in favoring joint regeneration together with preventing OA progression. Therefore, a mesenchymal stem cell line (SCP-1) was applied in order to assess the compatibility of the degradable material. Furthermore, an in vitro OA model utilizing SCP-1 cells based on the supplementation of the cytokines; IL-1β, TNF-α was established and disclosed the capability of Mg microparticles in differentiating SCP-1 cells into chondrogenic and osteogenic lineages proven through extracellular matrix staining and gene marker analysis. A concentration above 10 mM revealed a reduction in the cell viability by 50 %. An increase in the expression of collagens especially and proteoglycans (COL2A1, Aggrecan) as extracellular matrix proteins as well as an increase in osteogenic marker (ALP, BMP2) favoring the mineralization process were observed. The inflammatory condition reduced the viability and productivity of the applied stem cell line. However, the application of Mg microparticles induced a cell recovery and reduction of inflammation marker such as MMP1 and IL6. The cytocompatible and the ability of Mg microparticles in supporting bone and cartilage repair mechanisms in vitro even under inflammatory conditions make biodegradable Mg microparticles a suitable implant material to treat OA therapy.Acknowledgements: This project OAMag was funded by the German Research Foundation (project number 404534760). The author thank Dr. Björn Wiese (hereon) for the production of Mg based material and Prof. Böcker (MUM Musculoskeletal University Center Munich) for the provision of SCP-1 cell line.

Machine learning for forecasting the biomechanical behavior of orthopedic bone plates fabricated by fused deposition modeling

Purpose Three-dimensional (3D) printing is highly dependent on printing process parameters for achieving high mechanical strength. It is a time-consuming and expensive operation to experiment with different printing settings. The current study aims to propose a regression-based machine learning model to predict the mechanical behavior of ulna bone plates. Design/methodology/approach The bone plates were formed using fused deposition modeling (FDM) technique, with printing attributes being varied. The machine learning models such as linear regression, AdaBoost regression, gradient boosting regression (GBR), random forest, decision trees and k-nearest neighbors were trained for predicting tensile strength and flexural strength. Model performance was assessed using root mean square error (RMSE), coefficient of determination (R2) and mean absolute error (MAE). Findings Traditional experimentation with various settings is both time-consuming and expensive, emphasizing the need for alternative approaches. Among the models tested, GBR model demonstrated the best performance in predicting both tensile and flexural strength and achieved the lowest RMSE, highest R2 and lowest MAE, which are 1.4778 ± 0.4336 MPa, 0.9213 ± 0.0589 and 1.2555 ± 0.3799 MPa, respectively, and 3.0337 ± 0.3725 MPa, 0.9269 ± 0.0293 and 2.3815 ± 0.2915 MPa, respectively. The findings open up opportunities for doctors and surgeons to use GBR as a reliable tool for fabricating patient-specific bone plates, without the need for extensive trial experiments. Research limitations/implications The current study is limited to the usage of a few models. Other machine learning-based models can be used for prediction-based study. Originality/value This study uses machine learning to predict the mechanical properties of FDM-based distal ulna bone plate, replacing traditional design of experiments methods with machine learning to streamline the production of orthopedic implants. It helps medical professionals, such as physicians and surgeons, make informed decisions when fabricating customized bone plates for their patients while reducing the need for time-consuming experimentation, thereby addressing a common limitation of 3D printing medical implants.

Optimizing Orthopaedic Bone Plates for Directed Energy Deposition with Generative Design and Topological Optimization Approaches

Directed Energy Deposition (DED), a metal additive manufacturing technique, shows promise for future orthopaedic applications, especially in bone plate manufacturing. The need for patient-specific solutions in orthopaedics is growing, driven by the limitations of traditional bone plates made from stainless steel or titanium alloys and the rising incidence of complex fractures. This paper explores the design of orthopaedic bone plates using Generative Design (GD) and Topological Optimization (TO), aimed at eventual production through DED. By focusing on design, the research addresses challenges like stress shielding, caused by the modulus disparity between conventional plate materials and natural bone. Significant findings include mass reductions of 43.7% and 44.2% for GD designs GD1 and GD2, respectively, and a 36% reduction for the TO design TO1, enhancing biomechanical performance with improved strain values. The findings demonstrate GD’s effectiveness in generating anatomically congruent implants, showcasing advancements in personalized care and fracture treatment. The integration of GD and DED within the Design for Additive Manufacturing (DfAM) framework offers a promising pathway for future research focused on refining patient-specific designs and manufacturing processes, aligning with the evolving needs of orthopaedic treatments.

Functional Outcome of Distal Humerus Intra-articular Fractures Treated with Pre-contoured Anatomical Locking Plates

Introduction: The most difficult therapeutic challenge is treating humerus fractures, which might result in a subpar functional outcome. It is anticipated that early mobilization, anatomic reduction, and internal fixation will enhance the functional results. The purpose of this study is to assess the functional result, intercondylar fixation rate, and anatomically pre-contoured locking plate treatment of a distal humerus fracture. Material and Method: This prospective research included patients with type 13-C2 distal humerus fractures, regardless of sex, who were hospitalized. Using the modified triceps tongue flap method, all patients received open reduction and internal fixation with anatomic pre-contoured locking plates and screws. Patients underwent 6 months of follow-up after surgery. They had follow-up evaluations using the Mayo Elbow Performance Score (MEPS) for clinical, radiological, and functional assessments. The Chi-square test was used to analyze the outcomes. Observations: Males accounted for the majority of injuries (66.7% vs. 33.3%). The age distribution was 36.93 ± 14.67. Traffic accidents were the most common cause of injuries (66.7%). The most frequently affected side was the right upper limb (76.7%). Eighty percent of the patients had MEPS scores that were excellent or good overall. At the fracture site, the radiological union took an average of 10.2 ± 2.11 weeks. In the 6th week, the mean extension-flexion arc was 32.06°–104.06°, and in the 6th month, it was 11.55°–124.16°. Early superficial infection (3.3%), malunion (3.3%), ulnar neuropraxia (3.3%), and chronic osteomyelitis (3.3%) were the consequences. In conclusion, the functional result of the elbow was effectively preserved in distal humerus fractures treated with anatomic pre-contoured locking plates. Keywords: Elbow joint, distal humerus intra articular fractures, bone plates, articular range of motion, osteomyelitis, MEPS, pre-contoured anatomical locking plate.

Early implant placement in sites with ridge preservation or spontaneous healing: histologic, profilometric, and CBCT analyses of an exploratory RCT.

The aim of this study was to compare changes in soft and hard tissue and the histologic composition following early implant placement in sites with alveolar ridge preservation or spontaneous healing (SH), as well as implant performance up to 1 year after crown insertion. Thirty-five patients with either intact buccal bone plates or dehiscence of up to 50% following single-tooth extraction of incisors, canines, or premolars were included in the study. They were randomly assigned to undergo one of three procedures: deproteinized bovine bone mineral with 10% collagen (DBBM-C) covered by a collagen matrix (DBBM-C/CM), DBBM-C alone, or SH. At 8 weeks, implant placement was carried out, and cone-beam computed tomography scans and impressions were obtained for profilometric analysis. Patients were followed up after the final crown insertion and again at 1 year post-procedure. Within the first 8 weeks following tooth extraction, the median height of the buccal soft tissue contour changed by -2.11 mm for the DBBM-C/CM group, -1.62 mm for the DBBM-C group, and -1.93 mm for the SH group. The corresponding height of the buccal mineralized tissue changed by -0.27 mm for the DBBM-C/CM group, -2.73 mm for the DBBM-C group, and -1.48 mm for the SH group. The median contour changes between crown insertion and 1 year were -0.19 mm in the DBBM-C/CM group, -0.09 mm in the DBBM-C group, and -0.29 mm in the SH group. Major vertical and horizontal ridge contour changes occurred, irrespective of the treatment modality, up to 8 weeks following tooth extraction. The DBBM-C/CM preserved more mineralized tissue throughout this period, despite a substantial reduction in the overall contour. All 3 protocols led to stable tissues for up to 1 year.

Analysis of the anatomical relationship between the roots of three lower molars with the lingual bone plate and the mandibular canal using cone beam computed tomography

Odontectomy of the inferior wisdom teeth is considered to be one of the most frequently performed dental surgeries. It is certain that in order to prevent possible complications, the oral surgeon must have extensive knowledge regarding the anatomy of the region, possible intra– and postoperative risks, as well as treatment methods that would minimize the occurrence of complications. Of course, a key aspect in choosing the treatment technique and method is represented by the paraclinical investigations, and currently CBCT is considered to be the “golden” standard in visualizing the relationship of the third inferior molars to the neighboring anatomical structures, a fact that significantly contributes to the optimization the provision of dental surgical assistance. The purpose of this study was to reveal the role of the CBCT paraclinical radiological examination in the pre–surgical evaluation of the anatomical relationships of the roots of the lower third molars with the neighboring anatomical elements for the prophylaxis of postextractional complications. Material and methods. The prospective clinical study was based on the visualization of tomographic sections of 116 CBCTs, with a total of 160 inferior wisdom teeth, analyzing various study variables such as the relationship of the inferior wisdom teeth roots to the mandibular canal, to the lingual bony plate, root morphology, etc., with their subsequent statistical analysis. Results and discussion. The extraction of the lower wisdom teeth can be associated with the occurrence of various complications such as the association of postoperative infection, dislodging the teeth into the neighboring spaces, nerve damage. It is important to use preoperatively both the predictability scale of the difficulty of extraction of inferior third molar and the three–dimensional paraclinical investigations in order to plan a treatment plan involving low risks of intra– and postoperative complications. Conclusions. The use of three–dimensional paraclinical investigations such as CBCT are absolutely necessary both for visualizing the relationship between anatomical structures and for planning complex clinical cases.

Mathematical modeling of vancomycin release from Poly-L-Lactic Acid-Coated implants.

This study aimed to develop a mathematical model to predict the release profile and antibacterial efficacy of a vancomycin delivery system integrated with poly(L-lactic acid)-coated bone implants specifically designed for bone plates. Using Fickian diffusion principles within an ANSYS-CFX computational fluid dynamic model, we validated the model against our in vitro vancomycin release and agar diffusion studies, as well as previously published in vivo data, confirming the reliability of the model. The model predictions demonstrated the effectiveness of the system in inhibiting bacterial growth in surrounding tissue with no observed toxicity, with a peak vancomycin concentration of 0.95 mg/ml at 6 hours, followed by a decrease to levels that remained effective for antibacterial activity. Furthermore, a sensitivity analysis revealed that the model is particularly sensitive to the half-life of vancomycin, with a maximum sensitivity index of 0.8, indicating its greater impact on the prediction accuracy than the diffusion coefficient, which has a maximum sensitivity index of 0.5. Therefore, precise input of vancomycin's half-life is critical for accurate predictions. These findings offer substantial support for the efficacy of the local delivery system as a promising therapeutic approach against implant-associated infections.

«Старые» и новые венгерские погребения на левобережье Днестра

The article analyzes the materials obtained during the study of five Hungarian burials on the left bank of the Lower Dniester. Description of the of the barrow and the grave: Burial near the Butora village, which was sunk into an Early Bronze Age mound and contained a horse’s humerus and fragments of gold foil, was studied in 1978; it was previously published with erroneous cultural-chronological attribution or as uncertain. Two more graves were discovered in 1992 in Early Bronze Age mounds near the town of Slobodzeya. Until recently, archival documentation was considered lost, and anthropological materials and grave goods were not identified. А fragment of an iron steel was found in one of the burials. Bone plates for a bow, iron arrowheads, two iron knives (a long combat one and a short household one) were found in another burial. A Hungarian grave sunk in a Scythian mound was studied near Glinoe village, Slobodzeya district, in 2022, in the kurgan group “Sever”. A fire flint, an iron arrowhead, an awl and a knife, as well as gold foil and a horse’s humerus were found in the grave. A burial containing the humerus of small cattle and an iron arrowhead was excavated in 2023 in the Early Bronze Age mound situated at the “Kulak” cemetery near the Korotnoe village. Grave from the Butory cemetery, one of the burials near the town of Slobodzeya, as well as graves in the “Sever” group and from the “Kulak” cemetery were radiocarbon dated. Burial dating: Analogies to grave goods, as well as seven radiocarbon dates obtained in the Poznan, Kiev and Debrecen laboratories, allow us to date graves to the second half of the 9th – the first half of the 10th century. Final remarks: These burials, together with the Hungarian graves previously discovered in the North-Western Black Sea region, are archaeological sites left by the Hungarians east of the Carpathians immediately before finding their homeland.

Intra-Articular Injection of Chitin Nanofiber Attenuates Osteoarthritis: An Experimental Study in a Rat Model of Osteoarthritis.

This study aimed to evaluate the effect of chitin nanofibers (CNF) produced from crab shells as a medical material for the knee in an osteoarthritic rat model. The effect of intra-articular CNF injection was evaluated histologically among three groups: saline, hyaluronic acid (HA), and CNF injection groups. The Osteoarthritis Research Society International (OARSI) cartilage, subchondral bone, synovial, and meniscus scores were used for scoring. At 4 weeks, the CNF group had significantly lower scores than the saline group. The Synovial score was lower in HA and CNF groups at 4 weeks than in the saline group. At 4 weeks post-treatment, the thickening of the subchondral bone plate and angiogenesis were significantly reduced in the CNF treatment group compared to those in the saline treatment group (P = 0.02). The anti-inflammatory effects of CNF on knee osteoarthritis were comparable to that of HA in the early stages.

Development of thermally responsive composite bone plates for maxillofacial trauma treatment

Development of thermally responsive composite bone plates for maxillofacial trauma treatment

Soft-tissue volume augmentation using a connective tissue graft and a volume-stable collagen matrix with polydeoxyribonucleotide for immediate implant placement: a pilot study in a dog model.

The aims of this study were 1) to investigate the effects of a subepithelial connective tissue graft (SCTG) and a volume-stable collagen matrix (VCMX) on soft-tissue volume gain in the immediate implant placement protocol, and 2) to determine whether polydeoxyribonucleotide (PDRN) can enhance the effects of a VCMX. Dental implants were placed in 4 mongrel dogs immediately after extracting the distal roots of their third and fourth mandibular premolars. The gap between the implant and the buccal bone plate was filled with synthetic bone substitute particles. The following soft-tissue augmentation modalities were applied buccally: 1) control (no augmentation), 2) SCTG, 3) VCMX, and 4) VCMX/PDRN. After 4 months, histomorphometric analysis was performed. Tissue changes were evaluated using superimposed standard tessellation language (STL) files. Wound dehiscence was found in more than half of the test groups, but secondary wound healing was successfully achieved in all groups. Histomorphometrically, tissue thickness was favored in group SCTG at or above the implant platform level (IP), and group SCTG and the groups with VCMX presented similar tissue thickness below the IP. However, the differences in such thickness among the groups were minor. The keratinized tissue height was greater in group VCMX/PDRN than in groups SCTG and VCMX. Superimposing the STL files revealed a decrease in soft-tissue volume in all groups. Wound dehiscence after soft-tissue volume augmentation might be detrimental to obtaining the expected outcomes. PDRN appears not to have a positive effect on the soft-tissue volume gain.

Osteochondral tissue engineering in translational practice: histological assessments and scoring systems.

Osteochondral lesions are common pathological alterations in synovial joints. Different techniques have been designed to achieve osteochondral repair, and tissue-engineered osteochondral grafts have shown the most promise. Histological assessments and related scoring systems are crucial for evaluating the quality of regenerated tissue, and the interpretation and comparison of various repair techniques require the establishment of a reliable and widely accepted histological method. To date, there is still no consensus on the type of histological assessment and scoring system that should be used for osteochondral repair. In this review, we summarize common osteochondral staining methods, discuss the criteria regarding high-quality histological images, and assess the current histological scoring systems for osteochondral regeneration. Safranin O/Fast green is the most widely used staining method for the cartilage layer, whereas Gomori and Van Gieson staining detect new bone formation. We suggest including the graft-host interface and more sections together with the basic histological information for images. An ideal scoring system should analyze both the cartilage and bone regions, especially for the subchondral bone plate. Furthermore, histological assessments should be performed over a longer period of time to minimize discrepancies caused by defect size and animal species.

Biopolymeric membrane - a new concept in guided bone regeneration. Series of cases

Introduction. Different types of resorbable and non-resorbable membranes, cortical autogenous and allogenic bone plates, and prefabricated and perforated titanium meshes are currently used as guidance and support materials. All these devices present a series of advantages, but also disadvantages, such as gingival dehiscence with exposure and superinfection, additional trauma, and complete resorption of the bone graft. The objective of the study. This study emphasizes the importance of resorbable biopolymeric membranes in GBR. The retrospectively and descriptive analyses of the technique at 6 months postoperative time on a series of cases were performed. Materials and methods. GBR with resorbable biopolymer mesh was performed in 15 patients in 18 graft sites. Was analyzed just graft sites without any complication. The density of the newly formed bone under the augmentation membrane was evaluated postoperatively at 6 months using computed tomography (CBCT) according to the Hounsfield scale. Results. Results were interpreted in 18 graft sites and were evaluated at 6 months by paraclinical CBCT examination. After the polymer mesh GBR procedure, the mean radiodensity of the new bone obtained in the 18 sites was 1805 HU and the radiodensity of the native cortical bone next to the bone graft was 1793.4 HU

Immediate implant placement in the premolar maxillary area: a cone-beam computed tomography study.

This research aimed to investigate potential factors associated with the risk of perforation of the labial bone plate, nasal floor, or maxillary sinus floor during immediate implant placement (IIP) in the maxillary premolar area, utilizing a cone-beam computed tomography (CBCT) virtual study. CBCT exams from 179 eligible participants, encompassing 716 teeth, were included. Implants were virtually positioned in 2 orientations: along the long axis of the tooth (the prosthetically-driven position) and in an optimal position relative to adjacent anatomical structures (the bone-driven position). Binary logistic regression analysis was employed to assess potential associations between perforation or invasion and various covariates, including sex, age, tooth region, the distance from the tooth apex to the nasal floor or maxillary sinus floor, the angle between the prosthetically- and bone-driven positions (implant-line A angle [ILAA]), and the labial concavity angle (LCA). The mean ILAA was 18.3°±8.0°, and the angle was significantly larger for the second premolar compared to the first premolar. The mean minimum implant length was 13.0±2.1 mm, with a bone anchorage of 4 mm. The incidence of perforation was 84.1% for the prosthetically-driven position and 40.5% for the bone-driven position. Factors associated with a higher risk of cortical bone wall perforation or invasion of the 2-mm safety margin from surrounding anatomical structures (in the bone-driven position) included female sex, older age, shorter distance from the tooth apex to the nasal cavity/maxillary sinus, and smaller LCA. A high prevalence of cortical bone wall perforation or invasion of the 2-mm safety margin is anticipated when performing IIP in the maxillary premolar region.