1,720,980 research outputs found
Optimizing Immediate Loading with Immediate Implants
No full textThis chapter defines and elaborates on what is meant by "immediate loading." Dynamic guided implant surgery (dCAIS) or navigation uses advanced technology to facilitate precise implant placement based on cone-beam computed tomographic (CBCT) planning. Immediate implant placement with immediate loading requires a full understanding of the biological and technical essentials involved. The most crucial determinant for success with immediate loading of immediate implants is their primary stability. Both immediate non-occlusal and immediate occlusal loading can favor faster peri-implant bone formation. Internal conical connection implants are used for immediate non-occlusal and immediate occlusal loading provided that they are placed subcrestal, incorporate a platform switch feature and have peri-implant soft tissue thickness of 3 mm. Biconometric implant crown-to-abutment attachment can replace other forms of prosthesis retention. A novel approach meant to accelerate healing with immediate loading of immediate implants is discussed
The Effect of Implant Thread’s Pitch on Primary Stability: An In Vitro Polyurethane Study with Under-Preparation and Low-Speed Drilling
Full text linkBackground: The morphology of implant threads plays a crucial role in achieving primary stability, which is essential for successful osseointegration and immediate loading of dental implants. This study aimed to evaluate how different implant thread pitches and an under-preparation drilling technique impact primary stability using an in vitro model. Methods: The study was conducted on low-density polyurethane bone models with and without cortical layers. The following three different implant thread profiles were tested: CYROTH 0.40 (0.40 mm), CYROTH 0.45 (0.45 mm), and CYROTH T (0.35 mm). Two different drilling procedures were utilized, with diameters of 3.4 mm and 3.7 mm, at a low rotational speed of 30 rpm. Primary stability was assessed by measuring insertion torque (IT), removal torque (RT), and resonance frequency analysis (RFA). Results: The low rotational speed of 30 rpm was found to be effective for achieving favorable fixation parameters in all scenarios. The 0.45 mm thread consistently exhibited higher implant stability quotient (ISQ) values (from two to six points higher) compared to the 0.40 mm and standard 0.35 mm threads, while also requiring lower IT. The highest ISQ values were recorded in the 20 pounds per cubic foot (PCF) block with a cortical layer using the 0.45 mm thread and a 3.4 mm drill. The under-preparation using the 3.4 mm drill resulted in higher IT and RT values than the 3.7 mm drill. Conclusions: This study demonstrated that implant thread pitch and drilling technique are critical factors influencing primary stability. Utilizing a wider thread pitch (0.45 mm) along with an under-preparation drilling protocol can significantly improve implant stability, even in low-density bone, without the need for excessive IT. These findings suggest that selecting the appropriate implant macrogeometry and surgical technique can optimize the primary stability of dental implants
Finite element analysis of primary healing implants with different transmucosal designs
Full text linkPurpose: This study aimed to assess the response of peri-implant tissues, both hard and soft, to mechanical stress when using a primary healing implant (PHI) with two different transmucosal profiles: concave (Model A) and divergent (Model B). The investigation also sought to observe bone modeling under post-extraction conditions. Materials and methods: The methodology involved the creation of a three-dimensional bone model of the first molar region, derived from a computed tomography scan. Subsequently, two implants were inserted into the bone site and subjected to a loading force of 100 N at a 45° angle. Results: The results of stress analysis, using the von Mises criterion, indicated that Model A exhibited a more uniform stress distribution within the soft tissues, registering a maximum value of 75 MPa, in contrast to 126 MPa observed in Model B. Concerning implant stress, the peak value was recorded at the conometric connection zone between the implant and the abutment, measuring 138 MPa for Model B and 125 MPa for Model A. The study specifically analyzed cortical bone stress, which revealed levels of 72 MPa for Model B and 64 MPa for Model A. Additionally, stress distribution in immature bone ranged from 1.3 to 9 MPa for Model A and from 1.5 to 12 MPa for Model B. Conclusions: The finite element method represents a valuable tool for the design and optimization of implant shapes, taking into account occlusal loads and specific anatomical locations. This approach aims to enhance the stimulation of both soft and hard tissues, thereby mitigating the risk of implant failure
Insertion Torque, Removal Torque, and Resonance Frequency Analysis Values of Ultrashort, Short, and Standard Dental Implants: An In Vitro Study on Polyurethane Foam Sheets
Full text linkShort implants were introduced to reduce morbidity, treatment duration, and complex bone regeneration interventions in atrophic jaws and to improve patient-reported outcomes. This study aimed to determine the insertion torque (IT), removal torque (RT), and resonance frequency analysis (RFA) values of ultrashort (3 mm length), short (7 mm length), and standard implants (10 mm length) inserted in 1-, 2-, 3-, and 4-mm thickness polyurethane sheets with densities of 10, 20, and 30 pounds per cubic foot (PCF). Standard-length implants were the gold standard (control). Overall, short-length implant IT values were higher or similar to the control in most experimental conditions. Those inserted into a 3 mm/30 PCF lamina showed the highest IT values, whereas 5 mm diameter ultrashort-length implants inserted into 2 and 3 mm/20 PCF laminas were higher than other implants. RT values followed the same trend and RFA values were more appreciable in short- and standard-length implants in all the scenarios. However, ultrashort-length implants reached a primary stability comparable to that of standard implants in lower thicknesses. In conclusion, although further studies are needed to corroborate this in vitro model with preclinical and clinical studies, our data shed light on short- and ultrashort-length implants geometries to a potential application in critical atrophy of the posterior jaws
A 3D in vitro model of biphasic calcium phosphate (BCP) scaffold combined with human osteoblasts, osteoclasts, and endothelial cells as a platform to mimic the oral microenvironment for tissue regeneration
Full text linkObjectives: This study aimed to develop an innovative 3D in vitro model based on the biphasic calcium phosphate (BCP) scaffold combined with human osteoblasts (hOBs), osteoclasts (hOCs), and endothelial cells to evaluate its effects on bone and vascular cells behavior.
Methods: To this end, an optimized mixture of hydroxyapatite (HA) and β-tricalcium phosphate (TCP) with a weight ratio of 30/70 was employed to develop a BCP scaffold using the computer-aided design (CAD) approach. The BCP scaffold was combined with primary cultures of hOBs, hOCs and human umbilical vein endothelial cells (HUVECs).
Results: Morphometric analyses using scanning electron microscopy (SEM) and X-ray micro-computed tomography, along with biomechanical testing, revealed that BCP scaffold exhibited a regular 3D structure with large interconnected internal pores (700 μm) and high mechanical strength. In terms of biological behavior, after 14 days of tri-culture with hOBs, hMCs and HUVECs, SEM, immunofluorescence, and histological analyses showed that all cell types were viable and adhered well to the entire surface of the scaffold. Interestingly, SEM and energy-dispersive X-ray spectroscopy analyses also revealed on the BCP scaffold the presence of mineralized matrix crystals of Ca, P, O and C within a tissue-like cell layer produced by the interaction of the three cell types.
Conclusions: Data confirmed the high performance of the BCP scaffold through biomechanical studies. Notably, for the first time, this study demonstrated the feasibility of combining BCP scaffold with hOBs, hOCs, and HUVEC, which remained viable and maintained their native phenotypes, creating also tissue-like cell layer.
Clinical significance: Although further investigation is needed, these results underscore the potential to develop a 3D in vitro model that mimics the oral microenvironment, which could be valuable for BTE approaches in in vivo studies
Finite‐Element Analysis Study Comparing Titanium and Polyetheretherketone Caps in a Conometric Connection between Implant and Prosthesis
Full text linkProsthetic retention relies on the perfect adaptation between the cap and the abutment of a dental implant. The conometric connection ensures retention similar to cemented systems, preventing bacterial infiltration and sustaining a high implant success rate. Furthermore, the material used for the cap plays a crucial role in distributing stress on the implant components and bone. Traditionally, caps use titanium (Ti), but ongoing research investigates polyetheretherketone (PEEK) for its bone-like qualities and similar elasticity to Ti. In this finite-element analysis study, stress and strain distributions are compared between crestal and subcrestal implants using Ti and PEEK conometric caps, assessing retention through cap displacement to determine the material best suited for proper retention aligned with implant insertion depth. In the findings, an improvement in stress and strain is indicated on trabecular bone, a reduction in stress on cortical bone, and thus enhanced implant stability due to higher stresses around the implant threads, particularly with PEEK coping and subcrestal placement. Consequently, PEEK emerges as a promising substitute for Ti in conometric caps as it absorbs stress more effectively, distributing it across prosthetics to counter stress shielding and prevent implant failure.This finite-element analysis assesses stress and strain in peri-implant bone and implants with conometric titanium or polyetheretherketone (PEEK) caps, placed crestally or subcrestally. In the results, it is indicated that subcrestal placement of PEEK-capped implants reduces cortical bone stress and increases trabecular bone stress, suggesting its potential to enhance bone stimulation, implant stability, and prevent bone resorption.imag
Effect of Crestal Position on Bone–Implant Stress Interface of Three-Implant Splinted Prostheses: A Finite Element Analysis
Full text linkOptimizing stress distribution at the bone–implant interface is critical to enhancing the long-term biomechanical performance of dental implant systems. Vertical misalignment between splinted implants can result in elevated localized stresses, increasing the risk of material degradation and peri-implant bone resorption. This study employs three-dimensional finite element analysis (FEA) to evaluate the mechanical response of peri-implant bone under oblique loading, focusing on how variations in vertical implant platform alignment influence stress transmission. Four implant configurations with different vertical placements were modeled: (A) all crestal, (B) central subcrestal with lateral crestal, (C) lateral subcrestal with central crestal, and (D) all subcrestal. A 400 N oblique load was applied at 45° simulated masticatory forces. Von Mises stress distributions were analyzed in both cortical and trabecular bone, with a physiological threshold of 100 MPa considered for cortical bone. Among the models, configuration B exhibited the highest cortical stress, exceeding the physiological threshold. In contrast, configurations with uniform vertical positioning, particularly model D, demonstrated more favorable stress dispersion and lower peak values. Stress concentrations were consistently observed at the implant–abutment interface across all configurations, identifying this area as critical for design improvements. These findings underscore the importance of precise vertical alignment in implant-supported restorations to minimize stress concentrations and improve the mechanical reliability of dental implants. The results provide valuable insights for the development of next-generation implant systems with enhanced biomechanical integration and material performance under functional loading
Comparative Evaluation of Primary Stability in Truncated Cone Implants with Different Macro-Geometries in Low-Density Polyurethane Blocks Simulating Maxillary Sinus Rehabilitations
Full text linkAfter tooth loss, particularly in the posterior maxilla, the alveolar ridges undergo bone resorption. Therefore, ensuring the appropriate quantity and quality of alveolar bone is crucial for accurate implant positioning and achieving optimal esthetic and functional results. This study aimed to evaluate biomechanical parameters (insertion torque: IT, removal torque: RT, and implant stability quotient: ISQ) of distinct truncated cone implant designs (Sinus-plant and SLC) on polyurethane blocks simulating type D3 and D4 bone. SLC implants exhibited significantly higher IT, RT, and ISQ values compared to Sinus-plant implants, except in the 10 pounds per cubic foot (PCF) density block with a cortical layer for the IT (24.01 ± 0.91 vs. 23.89 ± 1.66 Ncm). The IT values for SLC implants ranged from 13.95 ± 0.19 Ncm in the lowest density block to 37.94 ± 0.45 Ncm in the highest density block, consistently providing significantly higher primary stability with an ISQ of approximately 70 in the highest density block. Despite lower ISQ in the lowest density block (48.60 ± 0.52 and 48.80 ± 0.42 in buccolingual and mesiodistal directions), it was deemed acceptable considering the inadequate bone densities in the maxillary region. These findings on SLC suggest potential clinical advantages, including reduced procedure duration and costs, improved stability, and the possibility of immediate implant placement following sinus augmentation, thereby streamlining the rehabilitation process
Complex Magnetic Fields: Harnessing the Electromagnetic Symphony for Possible Applications in Regenerative Medicine and Antifungal Properties
Full text linkComplex magnetic fields (CMFs) represent an emerging frontier in regenerative medicine, offering significant potential for innovative therapeutic strategies. This review examined both the theoretical foundations and practical applications of CMFs, focusing on their roles in tissue regeneration and antifungal activity. A comprehensive review of electronic databases (PubMed, Scopus, and Embase) identified seven pivotal studies on in vitro models concerning the CMF topic. Although the number of studies is limited, they collectively highlighted the promising therapeutic potential of CMFs in enhancing wound healing, reducing oxidative stress, and neuroinflammation in diabetic neuropathy, positively influencing mitochondrial function, modulating immune responses, promoting cellular communication, inhibiting the growth and adhesion of Candida albicans to medical surfaces, and enhancing dental pulp stem cell proliferation under inflammatory conditions. These findings suggested that CMFs may offer an eco-sustainable approach, effectively targeting pathogens while preserving human cell integrity. While the current body of research is insightful, it remains in its early stages. To fully leverage the therapeutic potential of CMFs, more comprehensive studies are needed to refine their application and confirm their effectiveness across diverse clinical scenarios. This is essential for integrating CMFs into clinical practice, where they promise to revolutionise treatment approaches
Assessment of Pyrogenic Response of Medical Devices and Biomaterials by the Monocyte Activation Test (MAT): A Systematic Review
Full text linkPyrogens are fever-inducing substances routinely investigated in health products through tests such as the Rabbit Pyrogen Test (RPT), the Limulus Amebocyte Lysate (LAL), and the Monocyte Activation Test (MAT). However, the applications of the MAT for medical devices and biomaterials remain limited. This work aimed to overview the studies evaluating the pyrogenicity of medical devices and biomaterials using the MAT, highlighting its successes and potential challenges. An electronic search was performed by December 2023 in PubMed, Scopus, and Web of Science, identifying 321 records which resulted in ten selected studies. Data were extracted detailing the tested materials, MAT variants, interferences, and comparisons between methods. Methodological quality was assessed using the ToxRTool, and the results were synthesized descriptively. The selected studies investigated various materials, including polymers, metals, and natural compounds, employing the different biological matrices of the MAT. Results showed the MAT’s versatility, with successful detection of pyrogens in most materials tested, though variability in sensitivity was noted based on the material and testing conditions. Challenges remain in optimizing protocols for different material properties, such as determining the best methods for direct contact versus eluate testing and addressing the incubation conditions. In conclusion, the MAT demonstrates significant potential as a pyrogen detection method for medical devices and biomaterials. However, continued research is essential to address existing gaps, optimize protocols, and validate the test across a broader range of materials
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