Total temporomandibular joint (TMJ) replacements reduce pain and improve quality of life in patients suffering from end-stage TMJ disorders, such as osteoarthritis and trauma. Jaw kinematics measurements following TMJ arthroplasty provide a basis for evaluating implant performance and jaw function. The aim of this study is to provide the first measurements of three-dimensional kinematics of the jaw in patients following unilateral and bilateral prosthetic TMJ surgeries. Jaw motion tracking experiments were performed on 7 healthy control participants, 3 unilateral and 1 bilateral TMJ replacement patients. Custom-made mouthpieces were manufactured for each participant's mandibular and maxillary teeth, with each supporting three retroreflective markers anterior to the participant's lip line. Participants performed 15 trials each of maximum jaw opening, lateral and protrusive movements. Marker trajectories were simultaneously measured using an optoelectronic tracking system. Laser scans taken of each dental plate, together with CT scans of each patient, were used to register the plate position to each participant's jaw geometry, allowing 3D condylar motion to be quantified from the marker trajectories. The maximum mouth opening capacity of joint replacement patients was comparable to healthy controls with average incisal inferior translations of 37.5mm, 38.4mm and 33.6mm for the controls, unilateral and bilateral joint replacement patients respectively. During mouth opening the maximum anterior translation of prosthetic condyles was 2.4mm, compared to 10.6mm for controls. Prosthetic condyles had limited anterior motion compared to natural condyles, in unilateral patients this resulted in asymmetric opening and protrusive movements and the capacity to laterally move their jaw towards their pathological side only. For the bilateral patient, protrusive and lateral jaw movement capacity was minimal. Total TMJ replacement surgery facilitates normal mouth opening capacity and lateral and inferior condylar movements but limits anterior condylar motion. This study provides future direction for TMJ implant design

The use of implant biomaterials for prosthetic reconstructive surgery and osteosynthesis is consolidated in the orthopaedic field, improving the quality of life of patients and allowing for healthy and better ageing. However, there is the lack of advanced innovative methods to investigate the potentialities of smart biomaterials, particularly for the study of local effects of implant and osteointegration. Despite the complex process of osseointegration is difficult to recreate in vitro, the growing challenges in developing alternative models require to set-up and validate new approaches. Aim of the present study is to evaluate an advanced in vitro tissue culture model of osteointegration of titanium implants in human trabecular bone. Cubic samples (1.5×1.5 cm) of trabecular bone were harvested as waste material from hip arthroplasty surgery (CE AVEC 829/2019/Sper/IOR); cylindrical defects (2 mm Ø, 6 mm length) were created, and tissue specimens assigned to the following groups: 1) empty defects- CTR-; 2) defects implanted with a cytotoxic copper pin (Merck cod. 326429)- CTR+; 3) defects implanted with standard titanium pins of 6 µm-rough (ZARE S.r.l) -Ti6. Tissue specimens were cultured in mini rotating bioreactors in standard conditions, weekly assessing viability. At the 8-week-timepoint, immunoenzymatic, microtomographic, histological and histomorphometric analyses were performed. The model was able to simulate the effects of implantation of the materials, showing a drop in viability in CTR+, differently from Ti6 which appears to have a trophic effect on the bone. MicroCT and histological analysis supported the results, with lower BV/TV and Tb.Th values observed in CTR- compared to CTR+ and Ti6 and signs of matrix and bone deposition at the implant site. The collected data suggest the reliability of the tested model which can recreate the osseointegration process in vitro and can therefore be used for preliminary evaluations to reduce and refine in vivo preclinical models. Acknowledgment: This work was supported by Emilia-Romagna Region for the project “Sviluppo di modelli biologici in vitro ed in silico per la valutazione e predizione dell'osteointegrazione di dispositivi medici da impianto nel tessuto osseo”

Post-surgical infections are still one of the most frequent adverse events in the prosthetic surgery. PMMA-based cements are widely employed in orthopaedic surgery as filler or prosthetic fixing device. The main problems associated with this material are poor bone integration and infection development. Aiming to avoid bacterial adhesion and to extend the longevity of implants, different solutions were proposed, both in terms of operative procedures and new materials development. Regarding the materials advancement, innovative PMMA-based composite bone cements, contemporaneously bioactive and antibacterial (without the use of antibiotics), were developed. The composites are based on a PMMA matrix containing a bioactive glass, doped with antibacterial ions (Ag+ or Cu++); so, the same filler shows at the same time the ability of promoting bone ingrowth and an antibacterial effect. Composite cements were characterized in terms of morphology and composition, curing parameters and mechanical properties; in vitro tests were performed to verify the material ability to release antibacterial ions and to promote the precipitation of hydroxyapatite. Moreover, cytotoxicity and antimicrobial properties were verified. The cements characteristics were tested using different commercial matrix and different viscosities; therefore, the proposed formulations represent an innovative solution for a new family of antibiotic-free, bioactive and antibacterial cements

Objectives

Implant-related infection is one of the most devastating complications in orthopaedic surgery. Many surface and/or material modifications have been developed in order to minimise this problem; however, most of the in vitro studies did not evaluate bacterial adhesion in the presence of eukaryotic cells, as stated by the ‘race for the surface’ theory. Moreover, the adherence of numerous clinical strains with different initial concentrations has not been studied.