Senso-Immunologic Prospects for Complex Regional Pain Syndrome Treatment

Complex regional pain syndrome (CRPS) is a chronic pain syndrome that occurs in tissue injuries as the result of surgery, trauma, or ischemia. The clinical features of this severely painful condition include redness and swelling of the affected skin. Intriguingly, it was recently suggested that transient receptor potential ankyrin 1 (TRPA1) is involved in chronic post-ischemia pain, a CRPS model. TRPA1 is a non-selective cation channel expressed in calcitonin gene-related peptide (CGRP)-positive primary nociceptors that becomes highly activated in ischemic conditions, leading to the generation of pain. In this review, we summarize the history of TRPA1 and its involvement in pain sensation, inflammation, and CRPS. Furthermore, bone atrophy is also thought to be a characteristic clinical sign of CRPS. The altered bone microstructure of CRPS patients is thought to be caused by aggravated bone resorption via enhanced osteoclast differentiation and activation. Although TRPA1 could be a target for pain treatment in CRPS patients, we also discuss the paradoxical situation in this review. Nociceptor activation decreases the risk of bone destruction via CGRP secretion from free nerve endings. Thus, TRPA1 inhibition could cause severe bone atrophy. However, the suitable therapeutic strategy is controversial because the pathologic mechanisms of bone atrophy in CRPS are unclear. Therefore, we propose focusing on the remission of abnormal bone turnover observed in CRPS using a recently developed concept: senso-immunology.

Implant Survival in Immediately Loaded Full-Arch Rehabilitations following an Anatomical Classification System—A Retrospective Study in 1200 Edentulous Jaws

This retrospective study analyzed implant survival of immediate implant-supported fixed complete denture (IFCD) treatment options (TOs) based on the level of alveolar atrophy (CC). Records of 882 patients receiving a total of 6042 implants at one private referral clinic between 2004 and 2020 were considered. The mean follow-up period was 3.8 ± 2.7 years. Cumulative implant survival rates (CSRs) were analyzed as a function of CCs and TOs according to Mantel-Haenszel and Mantel-Cox. Hazard risk ratios for implant loss were compared using Cox regression. Confounding factors were identified using mixed Cox regression models. The 2- and 5-year CSRs were 98.2% and 97.9%, respectively. Maxillary 2- and 5-year CSRs were lower (97.7% and 97.3%) compared to mandibular CSRs (99.8% and 98.6%) (p = 0.030 and 0.0020, respectively). The CC did not influence CSRs of IFCDs in the mandible (p = 0.1483 and 0.3014, respectively) but only in the maxilla (p = 0.0147 and 0.0111), where CSRs decreased with increasing atrophy. TOs did not statistically differ in terms of survival rate for a given level of alveolar atrophy. The adaption of IFCD treatments to the level of atrophy and patient-specific risk factors can result in high CSRs, even at different levels of bone atrophy.

How does the viability of bone-restricted osteocytes regulate bone atrophy?

How does the viability of bone-restricted osteocytes regulate bone atrophy? Osteocyte death is amplified in many bone diseases and is ubiquitous upon ageing. To date, the impact of osteocyte death on pathological bone loss is poorly studied due to the remote location of osteocytes. Within the ERC Starting Grant project “Unknown functions of Osteocyte DEath (ODE)” we will make use of new imaging and omics technologies to unravel this question.

Radiographic Evaluation of Bone Remodeling after Additively Manufactured Subperiosteal Jaw Implantation (AMSJI) in the Maxilla: A One-Year Follow-Up Study

Additively manufactured subperiosteal jaw implants (AMSJI) are patient-specific, 3D-printed, titanium implants that provide an alternative solution for patients with severe maxillary bone atrophy. The aim of this study was to evaluate the bony remodeling of the maxillary crest and supporting bone using AMSJI. Fifteen patients with a Cawood–Howell Class V or greater degree of maxillary atrophy were evaluated using (cone beam) computed tomography scans at set intervals: one month (T1) and twelve months (T2) after definitive masticatory loading of bilateral AMSJI implants in the maxilla. The postoperative images were segmented and superimposed on the preoperative images. Fixed evaluation points were determined in advance, and surface comparison was carried out to calculate and visualize the effects of AMSJITM on the surrounding bone. A total mean negative bone remodeling of 0.26 mm (SD 0.65 mm) was seen over six reference points on the crest. Minor bone loss (mean 0.088 mm resorption, SD 0.29 mm) was seen at the supporting bone at the wings and basal frame. We conclude that reconstruction of the severely atrophic maxilla with the AMSJI results in minimal effect on supporting bone. Reduced stress shielding with a biomechanically tuned subperiosteal implant does not induce radiographically significant crestal bone atrophy.

The use of laser welding in the immediate rehabilitation for dental patients with edentulou jaws

Necessary to take into account the effect of occlusal and non-axial loading in orthopedic treatment and rehabilitation of patients with edentulous jaws with implant-supported structures. Immediate stabilization, which achieved by intraoral welding, increases the posebility of success of implant osseointegration, and using immediate loading even in cases of bone atrophy for allows implants to be stabilized. The presented review of scientific literature on the use of laser welding in dentistry, the features of the application and the practical feasibility of immediate loading when splinting implants using intraoral welding. Many authors have investigated the use and effect of the parameters of a pulsed solid-state Nd:YAG laser for Ti and dental alloys. Scientists have proven the safety and effectiveness of using a dental Nd:YAG laser for welding metals directly in the oral cavity. The main risk for immediate loading implants is bone overload in the implants area during the first postoperative weeks, which can lead to their disintegration. Splinting prevent micro-displacement, distributes forces across multiple implants and shows highly effective immediate loading protocols. The expediency of immediate loading and the use of implant splinting with the intraoral welding prevents possible implant tilt and overload. The problem of using the method of immediate loading of implants with intraoral welding in dental orthopedic treatment has not been finally solved, and the well-known developments of the authors require further research and improvement.

Findings from recent studies by the Japan Aerospace Exploration Agency examining musculoskeletal atrophy in space and on Earth

The musculoskeletal system provides the body with correct posture, support, stability, and mobility. It is composed of the bones, muscles, cartilage, tendons, ligaments, joints, and other connective tissues. Without effective countermeasures, prolonged spaceflight under microgravity results in marked muscle and bone atrophy. The molecular and physiological mechanisms of this atrophy under unloaded conditions are gradually being revealed through spaceflight experiments conducted by the Japan Aerospace Exploration Agency using a variety of model organisms, including both aquatic and terrestrial animals, and terrestrial experiments conducted under the Living in Space project of the Japan Ministry of Education, Culture, Sports, Science, and Technology. Increasing our knowledge in this field will lead not only to an understanding of how to prevent muscle and bone atrophy in humans undergoing long-term space voyages but also to an understanding of countermeasures against age-related locomotive syndrome in the elderly.