INFECTED SILICONE CHIN IMPLANT AFTER IMPLANT-SUPPORTED JAW REHABILITATION: CASE REPORT AND LITERATURE REVIEW

To report the infected silicone chin implant due to the non-ideal placement of dental implants, in female patient, 67 years old. A patient unsatisfied with her facial profile had installed a silicone chin implant 25 years ago. Recently underwent surgery for the placement of dental implants in a region close to the silicone implant. The non-ideal positioning of the dental implants and close contact with the silicone implant led to the absence of osseointegration, with consequent mobility and infection of both. The silicone implant was removed with dental implant that shows mobility. In the imaging exams could be noted others complications of silicone implant like bone resorption and the formation of a narrow bone layer around the inferior border of implant. Alloplastic implants are an option for the esthetic correction of chin deformities. Solid silicone is biocompatible and highly resistant to degradation, with a minimal allergic reaction and risk of toxicity. However, a number of postoperative complications may arise, such as migration or displacement, extrusion, foreign body reaction, bone resorption, heterotopic bone formation and infection. The precise imaging exams are critical to arrive at a diagnosis and the best treatment plan.

Geology and taphonomy of a unique tyrannosaurid bonebed from the upper Campanian Kaiparowits Formation of southern Utah: implications for tyrannosaurid gregariousness

Tyrannosaurids are hypothesized to be gregarious, possibly parasocial carnivores engaging in cooperative hunting and extended parental care. A tyrannosaurid (cf. Teratophoneus curriei) bonebed in the late Campanian age Kaiparowits Formation of southern Utah, nicknamed the Rainbows and Unicorns Quarry (RUQ), provides the first opportunity to investigate possible tyrannosaurid gregariousness in a taxon unique to southern Laramidia. Analyses of the site’s sedimentology, fauna, flora, stable isotopes, rare earth elements (REE), charcoal content and taphonomy suggest a complex history starting with the deaths and transport of tyrannosaurids into a peri-fluvial, low-energy lacustrine setting. Isotopic and REE analyses of the fossil material yields a relatively homogeneous signature indicating the assemblage was derived from the same source and represents a fauna living in a single ecospace. Subsequent drying of the lake and fluctuating water tables simultaneously overprinted the bones with pedogenic carbonate and structurally weakened them through wet-dry cycling. Abundant charcoal recovered from the primary bone layer indicate a low temperature fire played a role in the site history, possibly triggering an avulsion that exhumed and reburied skeletal material on the margin of a new channel with minimal transport. Possible causes of mortality and concentration of the tyrannosaurids include cyanobacterial toxicosis, fire, and flooding, the latter being the preferred hypothesis. Comparisons of the RUQ site with other North American tyrannosaur bonebeds (Dry Island-Alberta; Daspletosaurus horneri-Montana) suggest all formed through similar processes. Combined with ichnological evidence, these tyrannosaur mass-burial sites could be part of an emerging pattern throughout Laramidia reflecting innate tyrannosaurid behavior such as habitual gregariousness.

The Effects of Crosslinking on the Rheology and Cellular Behavior of Polymer-Based 3D-Multilayered Scaffolds for Restoring Articular Cartilage

Polymer-based tri-layered (bone, intermediate and top layers) scaffolds used for the restoration of articular cartilage were prepared and characterized in this study to emulate the concentration gradient of cartilage. The scaffolds were physically or chemically crosslinked. In order to obtain adequate scaffolds for the intended application, the impact of the type of calcium phosphate used in the bone layer, the polymer used in the intermediate layer and the interlayer crosslinking process were analyzed. The correlation among SEM micrographs, physical-chemical characterization, swelling behavior, rheological measurements and cell studies were examined. Storage moduli at 1 Hz were 0.3–1.7 kPa for physically crosslinked scaffolds, and 4–5 kPa (EDC/NHS system) and 15–20 kPa (glutaraldehyde) for chemically crosslinked scaffolds. Intrinsic viscoelasticity and poroelasticity were considered in discussing the physical mechanism dominating in different time/frequency scales. Cell evaluation showed that all samples are available as alternatives to repair and/or substitute cartilage in articular osteoarthritis.

Evaluation of osteochondral-like tissues using human freeze-dried cancellous bone and chondrocyte sheets to treat osteochondral defects in rabbits

Human freeze-dried cancellous bone combined with human chondrocyte sheets have recently been used to construct an osteochondral-like tissue, which resembled a cartilage layer on a subchondral bone layer.

Diagnosis and Exercise Rehabilitation of Knee Joint Anterior Cruciate Ligament Injury Based on 3D-CT Reconstruction

The joint capsule of the knee joint is attached to the edges of various articular surfaces and is thin and loose. Therefore, ligament reinforcement is needed to protect the knee joint and increase the stability of the joint. It plays a vital role in human activities. In this paper, a 3D-CT three-dimensional reconstruction method is used to reconstruct the ACL natural femoral imprint and double-bone tract. The relative positional relationship between the two center points is compared, and the law is summarized to guide the improvement of ACL anatomic double-beam reconstruction under arthroscopy. The 3D reconstruction results suggest that the bone layer in the anterior medial portion is the thickest, forming a peak, and the thickness of the bone layer in the posterior medial portion gradually decreases in a stepwise manner. The entire bone tissue in the anterior medial portion and posterior medial portion is integrated into one body. The tissues are connected as a whole, and the thickness is relatively uniform. The two parts of the bone tissues are not connected. The CF tissue was inserted into the bone tissue in a zigzag pattern. The changes of CF tissues in the anterior medial and posteromedial CF tissues were similar, and they were distributed stepwise from the inside to the outside. According to the bone and CF spatial structure and changing rules, ACL is divided into medial and lateral beams. According to this study, it can be summarized that (1) 3D reconstruction can clearly reconstruct the natural footprint of ACL femoral stops and postoperative osseous position and (2) 3D reconstruction can be used to evaluate the position of osseous postoperative ACL anatomic double-beam reconstruction. Arthroscopy double-beam reconstruction of ACL is instructive.

Ultra-High Molecular Weight Polyethylene/Titanium-Hybrid Implant for Bone-Defect Replacement

A hybrid implant with a structure mimicking that of natural bone was developed. Titanium alloy Ti–6Al–4V prepared with three-dimensional (3D)-printing technology was used to simulate the cortical-bone layer. The mismatch in the mechanical properties of bone and titanium alloy was solved by creating special perforations in the titanium’s surface. Porous ultra-high molecular weight polyethylene (UHMWPE) with high osteogenous properties was used to simulate the cancellous-bone tissue. A method for creating a porous UHMWPE structure inside the titanium reinforcement is proposed. The porous UHMWPE was studied with scanning electron microscope (SEM) to confirm that the pores that formed were open, interconnected, and between 50 and 850 μm in size. Mechanical-compression tests done on the obtained UHMWPE/titanium-hybrid-implant samples showed that their mechanical properties simulated those of natural bone.

A Col I and BCP ceramic bi-layer scaffold implant promotes regeneration in osteochondral defects

A new bi-layer scaffold composed of Col I and BCP ceramic was prepared to regenerate osteochondral defect. The result demonstrated the bi-layer scaffold could effectively promote the regeneration of both the cartilage and the subchondral bone layer.