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Aim of the study The success of the implant therapy is co-dependent on the correct pre-implant assessment of the general, loco-regional and local status, the surgical and post-surgical stage or prosthetics as well as maintenance. In order to appreciate and evaluate the candidate for implanted therapy, a series of markers or clinical-biological indices are followed. The present paper proposes an updated synthesis of the opinions from the specialized literature regarding them, with the aim of preparing an update regarding the scientific results of recent years. Material and methods Systematic reviews, meta-analyses on the influence of general and local factors on the success of implant therapy, clinical-biological indices, success rate, peri-implantation, using electronic platforms available until June 26, 2023, were included for analysis. ​Results Clinical-biological indicators of general condition influence the patient’s response both in the immediate post-therapeutic healing stage and long-term implant retention. At the same time, the patient’s general condition conditions the time and extent of the surgical intervention. Conclusions A number of general conditions are mentioned in the literature that contraindicate the surgical intervention in ambulatory conditions, such as myocardial infarction more recent than 6-12 months, acute leukemia, stroke more recent than 12 months.

Background: Implant infections caused by biofilm forming bacteria are a major threat in orthopedic surgery. Delivering antibiotics directly to an implant affected by a bacterial biofilm via superparamagnetic nanoporous silica nanoparticles could present a promising approach. Nevertheless, short blood circulation half-life because of rapid interactions of nanoparticles with the host's immune system hinder them from being clinically used. The aim of this study was to determine the temporal in vivo resolution of magnetic nanoporous silica nanoparticle (MNPSNP) distribution and the effect of PEGylation and clodronate application using PET/CT imaging and gamma counting in an implant mouse model. Methods: PEGylated and non-PEGylated MNPSNPs were radiolabeled with gallium-68 (68Ga), implementing the chelator tris(hydroxypyridinone). 36 mice were included in the study, 24 mice received a magnetic implant subcutaneously on the left and a titanium implant on the right hind leg. MNPSNP pharmacokinetics and implant accumulation was analyzed in dependence on PEGylation and additional clodronate application. Subsequently gamma counting was performed for further final analysis. Results: The pharmacokinetics and biodistribution of all radiolabeled nanoparticles could clearly be visualized and followed by dynamic PET/CT imaging. Both variants of 68Ga-labeled MNPSNP accumulated mainly in liver and spleen. PEGylation of the nanoparticles already resulted in lower liver uptakes. Combination with macrophage depletion led to a highly significant effect whereas macrophage depletion alone could not reveal significant differences. Although MNPSNP accumulation around implants was low in comparison to the inner organs in PET/CT imaging, gamma counting displayed a significantly higher %I.D./g for the tissue surrounding the magnetic implants compared to the titanium control. Additional PEGylation and/or macrophage depletion revealed no significant differences regarding nanoparticle accumulation at the implantation site. Conclusion: Tracking of 68Ga-labeled nanoparticles in a mouse model in the first critical hours post-injection by PET/CT imaging provided a better understanding of MNPSNP distribution, elimination and accumulation. Although PEGylation increases circulation time, nanoparticle accumulation at the implantation site was still insufficient for infection treatment and additional efforts are needed to increase local accumulation. [ABSTRACT FROM AUTHOR]

For any dental implant procedure that is being carried out, the success will depend on a thorough preoperative investigation. The quality, quantity and the volume of available bone at the planned implant site has to be assessed properly when planning a dental implant placement. When we speak of the forementioned aspects pre-surgical imaging and its co-relation to clinical findings help assess the relation to the amount of bone available from underlying vital parts namely the sinus cavities, nasal floor, nerves, teeth and vessels. Different radiographic modalities have been advocated for its assessment. Intra Oral Periapical radiograph (two-dimensional) is one such modality that has lost its importance after the introduction of more advanced techniques like Cone Beam Tomography (three-dimensional). This article will help us understand how two-dimensional and three-dimensional imaging modalities go hand in hand while treating dental patients. It will also explain why the conventional imaging technologies are still required in this era of modern methods of imaging. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the accuracy and reliability of cone-beam computerized tomography (CBCT) in measuring thinning bone surrounding dental implants. Three implants were inserted into the mandible of a domestic pig at 6 different bone thicknesses on the vestibular and the lingual sides, and measurements were recorded using CBCT. The results were obtained, analyzed, and compared with areas without implants. Our results indicated that the bone thickness and the neighboring implants decreased the accuracy and reliability of CBCT for measuring bone volume around dental implants. We concluded that CBCT slightly undermeasured the bone thickness around the implant, both buccally and orally, compared with the same thickness without the implant. These results support that using the i-CAT NG with a 0.2 voxel size is not accurate for either qualitative or quantitative bone evaluations, especially when the bone is thinner than 0.72 mm in the horizontal dimension. [ABSTRACT FROM AUTHOR]

Imaging forms an integral component for diagnosis of dental and in specific periodontal diseases. To date, intra-oral radiographic techniques are the main non-invasive diagnostic aids for the detection and assessment of internal changes in mineralized periodontal tissues like alveolar bone. These analog radiographic techniques suffer from inherent limitations like: Two dimensional projection, magnification, distortion, superimposition and misrepresentation of anatomic structures. The evolution of novel imaging modalities, namely cone beam computed tomography, tuned aperture CT empowered dental researchers to visualize the periodontium three dimensionally. This improves interpretation of structural and biophysical changes, ensures densitometric assessments of dentoalveolar structures including variations in alveolar bone density, and peri-implant bone healing more precisely. This detailed review, highlights current leading edge concepts, envisions a wide range of imaging modalities which pave the way for better understanding and early intervention of periodontal diseases. [ABSTRACT FROM AUTHOR]

Diagnostic imaging plays an important role in evaluating the dental implant patient. Many types of radiographic imaging are recommended for treatment planning for implants. These include panoramic, periapical and occlusal radiographs, conventional and computed tomography (CT) and MRI. The clinician needs to identify the best method for each clinical situation. This article gives an overview of the various available imaging modalities at our disposal with the advantages and limitations of each. [ABSTRACT FROM AUTHOR]

The likelihood of finding manufactured components (surgical tools, implants, etc.) within a tomographic field-of-view has been steadily increasing. One reason is the aging population and proliferation of prosthetic devices, such that more people undergoing diagnostic imaging have existing implants, particularly hip and knee implants. Another reason is that use of intraoperative imaging (e.g., cone-beam CT) for surgical guidance is increasing, wherein surgical tools and devices such as screws and plates are placed within or near to the target anatomy. When these components contain metal, the reconstructed volumes are likely to contain severe artifacts that adversely affect the image quality in tissues both near and far from the component. Because physical models of such components exist, there is a unique opportunity to integrate this knowledge into the reconstruction algorithm to reduce these artifacts. We present a model-based penalized-likelihood estimation approach that explicitly incorporates known information about component geometry and composition. The approach uses an alternating maximization method that jointly estimates the anatomy and the position and pose of each of the known components. We demonstrate that the proposed method can produce nearly artifact-free images even near the boundary of a metal implant in simulated vertebral pedicle screw reconstructions and even under conditions of substantial photon starvation. The simultaneous estimation of device pose also provides quantitative information on device placement that could be valuable to quality assurance and verification of treatment delivery. [ABSTRACT FROM AUTHOR]

Objectives: To briefly review the mathematical background of beam-hardening artifacts in cone-beam computed tomography (CBCT)-reconstruction and to investigate geometrical properties relevant for these reconstruction errors. By means of simulated and experimental results, beam-hardening effects caused by titanium implants are evaluated. Materials and methods: The geometrical and physical properties of the acquisition process of the projections used for 3D reconstruction are investigated and their effects on the CBCT images in the presence of titanium implants are derived. Beam-hardening effects are computed for a simplified polychromatic situation (three energy subsets of 80 and 110 kV) and compared with experimental results from a hard-plaster phantom containing two ‘implants’ (pure titanium rods; 4 mm diameter) exposed in two CBCT machines. Results: Massive absorption within a typical implant body (diameter: 4 mm) was computed for the low-energy subset of both energies (80 kV: 99.7%; 110 kV: 90.9%), whereas the high-energy subsets are only marginally absorbed (80 kV: 14.8%; 110 kV: 11.3%). Accordingly, phantom data revealed drastically reduced gray values in artifact-affected regions (3DAccuitomo: −46% to −51%) or (3DExam: −55%) plus increased noise (+67% vs. +73%), when compared with unaffected regions. Conclusions: Our theoretical and experimental results prove massive beam-hardening artifacts for a typical implant diameter and typical energies of up-to-date CBCT machines. Meaningful artifact reduction has to be based on more sophisticated mathematical modeling of the actual physical image acquisition process rather than on postprocessing of the erroneous results obtained from the rather crude reconstruction algorithms used presently. To cite this article: Schulze RKW, Berndt D, d'Hoedt B. On cone-beam computed tomography artifacts induced by titanium implants. Clin. Oral Impl. Res. 21, 2008; 100–107. [ABSTRACT FROM AUTHOR]

Background Context: Image quality and implant detectability by conventional imaging methods are suboptimal for perioperative spinal diagnostics, primarily limited by implant-related artifacts. Purpose: To evaluate the imaging quality of various intervertebral spacers examined by flat-panel detector-based volumetric computed tomography (FD-VCT) versus magnetic resonance imaging (MRI). Study Design/setting: A preclinical comparative study on an experimental porcine model. The study was performed at a university research facility. Methods: Three different intervertebral spacer types (titanium, carbon fiber-reinforced polymer, cobalt-chrome-molybdenum) were implanted in a cadaveric porcine spine and then examined by MRI using T1-weighted spin echo (T1w-SE) and turbo spin echo (T1w-TSE) sequences. Comparative imaging was performed with an experimentally approved FD-VCT prototype featuring two-dimensional and three-dimensional imaging and high isotropic spatial resolution. Data analysis focused on spacer shape, implant positioning, and implant-bone interface. Results: Compared with MRI, and despite the use of T1w-SE and T1w-TSE sequences, the image quality and detectability of all target characteristics were better with FD-VCT absent the usual artifacts. Using its option for implant-specific imaging, the experimental FD-VCT imager allowed reliable determination of additional variables such as dimension and volume. Conclusions: This experimental study provides initial evidence that FD-VCT produces excellently sharp, high-accuracy, artifact-free imaging quality that is superior to MRI in distinguishing key characteristics of intervertebral implants in a preclinical setting. [ABSTRACT FROM AUTHOR]

Non-invasive longitudinal imaging of osseointegration of bone implants is essential to ensure a comprehensive, physical and biochemical understanding of the processes related to a successful implant integration and its long-term clinical outcome. This study critically reviews the present imaging techniques that may play a role to assess the initial stability, bone quality and quantity, associated tissue remodelling dependent on implanted material, implantation site (surrounding tissues and placement depth), and biomarkers that may be targeted. An updated list of biodegradable implant materials that have been reported in the literature, from metal, polymer and ceramic categories, is provided with reference to the use of specific imaging modalities (computed tomography, positron emission tomography, ultrasound, photoacoustic and magnetic resonance imaging) suitable for longitudinal and non-invasive imaging in humans. The advantages and disadvantages of the single imaging modality are discussed with a special focus on preclinical imaging for biodegradable implant research. Indeed, the investigation of a new implant commonly requires histological examination, which is invasive and does not allow longitudinal studies, thus requiring a large number of animals for preclinical testing. For this reason, an update of the multimodal and multi-parametric imaging capabilities will be here presented with a specific focus on modern biomaterial research. [ABSTRACT FROM AUTHOR]

Purpose: Atherosclerosis detection remains challenging in coronary CT angiography for patients with cardiac implants. Pacing electrodes of a pacemaker or lead components of a defibrillator can create substantial blooming and streak artifacts in the heart region, severely hindering the visualization of a plaque of interest. We present a novel reconstruction method that incorporates a deformable model for metal leads to eliminate metal artifacts and improve anatomy visualization even near the boundary of the component., Methods: The proposed reconstruction method, referred as STF-dKCR, includes a novel parameterization of the component that integrates deformation, a 3D-2D preregistration process that estimates component shape and position, and a polyenergetic forward model for x-ray propagation through the component where the spectral properties are jointly estimated. The methodology was tested on physical data of a cardiac phantom acquired on a CBCT testbench. The phantom included a simulated vessel, a metal wire emulating a pacing lead, and a small Teflon sphere attached to the vessel wall, mimicking a calcified plaque. The proposed method was also compared to the traditional FBP reconstruction and an interpolation-based metal correction method (FBP-MAR)., Results: Metal artifacts presented in standard FBP reconstruction were significantly reduced in both FBP-MAR and STF-dKCR, yet only the STF-dKCR approach significantly improved the visibility of the small Teflon target (within 2 mm of the metal wire). The attenuation of the Teflon bead improved to 0.0481 mm -1 with STF-dKCR from 0.0166 mm -1 with FBP and from 0.0301 mm -1 with FBP-MAR - much closer to the expected 0.0414 mm -1 ., Conclusion: The proposed method has the potential to improve plaque visualization in coronary CT angiography in the presence of wire-shaped metal components.

The aim of this study was to assess the accuracy and reliability of cone-beam computerized tomography (CBCT) in measuring thinning bone surrounding dental implants. Three implants were inserted into the mandible of a domestic pig at 6 different bone thicknesses on the vestibular and the lingual sides, and measurements were recorded using CBCT. The results were obtained, analyzed, and compared with areas without implants. Our results indicated that the bone thickness and the neighboring implants decreased the accuracy and reliability of CBCT for measuring bone volume around dental implants. We concluded that CBCT slightly undermeasured the bone thickness around the implant, both buccally and orally, compared with the same thickness without the implant. These results support that using the i-CAT NG with a 0.2 voxel size is not accurate for either qualitative or quantitative bone evaluations, especially when the bone is thinner than 0.72 mm in the horizontal dimension.

Dental implant is a device made of alloplastic (foreign) material implanted into the jaw bone beneath the mucosal layer to support a fixed or removable dental prosthesis. Dental implants are gaining immense popularity and wide acceptance because they not only replace lost teeth but also provide permanent restorations that do not interfere with oral function or speech or compromise the self-esteem of a patient. Appropriate treatment planning for replacement of lost teeth is required and imaging plays a pivotal role to ensure a satisfactory outcome. The development of pre-surgical imaging techniques and surgical templates helps the dentist place the implants with relative ease. This article focuses on various types of imaging modalities that have a pivotal role in implant therapy.

Because tomographic reconstructions are ill-conditioned, algorithms that incorporate additional knowledge about the imaging volume generally have improved image quality. This is particularly true when measurements are noisy or have missing data. This paper presents a general reconstruction framework for including attenuation contributions from objects known to be in the field-of-view. Components such as surgical devices and tools may be modeled explicitly as part of the attenuating volume but are inexactly known with respect to their locations poses, and possible deformations. The proposed reconstruction framework, referred to as Known-Component Reconstruction (KCR), is based on this novel parameterization of the object, a likelihood-based objective function, and alternating optimizations between registration and image parameters to jointly estimate the both the underlying attenuation and unknown registrations. A deformable KCR (dKCR) approach is introduced that adopts a control point-based warping operator to accommodate shape mismatches between the component model and the physical component, thereby allowing for a more general class of inexactly known components. The KCR and dKCR approaches are applied to low-dose cone-beam CT data with spine fixation hardware present in the imaging volume. Such data is particularly challenging due to photon starvation effects in projection data behind the metallic components. The proposed algorithms are compared with traditional filtered-backprojection and penalized-likelihood reconstructions and found to provide substantially improved image quality. Whereas traditional approaches exhibit significant artifacts that complicate detection of breaches or fractures near metal, the KCR framework tends to provide good visualization of anatomy right up to the boundary of surgical devices.