Neural habituation during acute stress signals a blunted endocrine response and poor resilience.

BACKGROUND: A blunted hypothalamic-pituitary-adrenal (HPA) axis response to acute stress is associated with psychiatric symptoms. Although the prefrontal cortex and limbic areas are important regulators of the HPA axis, whether the neural habituation of these regions during stress signals both blunted HPA axis responses and psychiatric symptoms remains unclear. In this study, neural habituation during acute stress and its associations with the stress cortisol response, resilience, and depression were evaluated. METHODS: Seventy-seven participants (17-22 years old, 37 women) were recruited for a ScanSTRESS brain imaging study, and the activation changes between the first and last stress blocks were used as the neural habituation index. Meanwhile, participants' salivary cortisol during test was collected. Individual-level resilience and depression were measured using questionnaires. Correlation and moderation analyses were conducted to investigate the association between neural habituation and endocrine data and mental symptoms. Validated analyses were conducted using a Montreal Image Stress Test dataset in another independent sample (48 participants; 17-22 years old, 24 women). RESULTS: Neural habituation of the prefrontal cortex and limbic area was negatively correlated with cortisol responses in both datasets. In the ScanSTRESS paradigm, neural habituation was both positively correlated with depression and negatively correlated with resilience. Moreover, resilience moderated the relationship between neural habituation in the ventromedial prefrontal cortex and cortisol response. CONCLUSIONS: This study suggested that neural habituation of the prefrontal cortex and limbic area could reflect motivation dysregulation during repeated failures and negative feedback, which might further lead to maladaptive mental states.

Application of computer-aided design and 3D-printed template for accurate bone augmentation in the aesthetic region of anterior teeth.

PURPOSE: To explore the outcomes of bone augmentation in the aesthetic zone of the anterior teeth using computer-aided design and a 3D-printed template. METHODS: Ten patients with severe bone defects in the aesthetic zone of anterior teeth were included in the study; CT data were collected before surgery. The design of the osteotomy line in the bone defect area was determined under computer simulation. The position parameters and osteotomy line of the free bone were determined via virtual surgery. A 3D-printed template was prepared to guide the accurate placement of the bone graft. Reexamination was conducted to evaluate the position of the bone graft immediately after the operation and the resorbed capacity of the bone graft before implant restoration. RESULTS: The position of the bone graft was consistent with the preoperative design. The amount of bone graft resorbed was within the acceptable range three months after the operation, and the effect of implant restoration was satisfactory. CLINICAL SIGNIFICANCE: Use of computer-aided design and a 3D-printed template can be an effective approach for accurate bone augmentation in the aesthetic zone of the anterior teeth.

Computer-Aided Design and Three-Dimensional-Printed Surgical Templates for Second-Stage Mandibular Reconstruction.

It is extremely difficult in clinical practice to accurately reset the physiologic positions of the mandibular condyle and ramus because of ongoing bone remodeling, muscle stretching, occlusal disorders, and other factors; this makes it difficult to obtain a good shape for a reconstructed mandible, as well as a good condylar position. The present study aimed to investigate a standardized method for mandibular reconstruction in cases of obsolete mandibular defects, using a 3-dimensional (3D)-printed surgical template enhanced by computer-aided design. We collected computed tomography data preoperatively to computerize the physiologic positions of the mandibular condyle and ramus on the sagittal, axial, and coronal planes. Surgical simulation and 3D-printed template preparation were then conducted to assist in the implementation of actual surgery. Postoperative review was performed to assess the repositioning of the condyle, where patients were found to regain a satisfactory condyle position. Reconstruction error was ±0.56 mm, fulfilling the preoperative design. No complications and discomfort were reported. Overall, the combined use of computer-aided design and 3D-printed surgical templates can standardize mandibular reconstruction in cases of obsolete mandibular body defects.

A Rapidly Self-Healing Host-Guest Supramolecular Hydrogel with High Mechanical Strength and Excellent Biocompatibility.

It is still a challenge to achieve both excellent mechanical strength and biocompatibility in hydrogels. In this study, we exploited two interactions to form a novel biocompatible, slicing-resistant, and self-healing hydrogel. The first was molecular host-guest recognition between a host (isocyanatoethyl acrylate modified ß-cyclodextrin) and a guest (2-(2-(2-(2-(adamantyl-1-oxy)ethoxy)ethoxy)ethoxy)ethanol acrylate) to form "three-arm" host-guest supramolecules (HGSMs), and the second was covalent bonding between HGSMs (achieved by UV-initiated polymerization) to form strong cross-links in the hydrogel. The host-guest interaction enabled the hydrogel to rapidly self-heal. When it was cut, fresh surfaces were formed with dangling host and guest molecules (due to the breaking of host-guest recognition), which rapidly recognized each other again to heal the hydrogel by recombination of the cut surfaces. The smart hydrogels hold promise for use as biomaterials for soft-tissue repair.

Static and Temporal Dynamic in Functional Connectivity of Large-scale Brain Networks During Acute Stress Regulate Stress Resilience Differently: The Promotion Role of Trait Resilience.

Stress resilience has been largely regarded as a process in which individuals actively cope with and recover from stress. Over the past decade, the emergence of large-scale brain networks has provided a new perspective for the study of the neural mechanisms of stress. However, the role of inter-network functional-connectivity (FC) and its temporal fluctuations in stress resilience is still unclear. To bridge this knowledge gap, seventy-seven participants (age, 17-22 years, 37 women) were recruited for a ScanSTRESS brain imaging study. A static perspective was initially adopted, using changes in FC that obtained from stress vs. control condition during the entire stress induction phase as a static indicator. Further, changes in FC between different stress runs were analyzed as an index of temporal dynamics. Stress resilience was gauged using salivary cortisol levels, while trait resilience was measured via behavioral-activation-system (BAS) sensitivity. Results found that, for the static index, enhanced FC between the salience-network (SN), default-mode-network (DMN) and limbic-network (LBN) during acute stress could negatively signal stress resilience. For the temporal dynamics index, FC among the dorsal-attention-network (DAN), central-executive-network (CEN) and visual-network (VN) decreased significantly during repeated stress induction. Moreover, the decline of FC positively signaled stress resilience, and this relationship only exist in people with high BAS. The current research elucidates the intricate neural underpinnings of stress resilience, offering insights into the adaptive mechanisms underlying effective stress responses.

The role of personal, relational, and collective self-esteem in predicting acute salivary cortisol response and perceived stress.

Personal self-esteem (PSE) has been well recognized as a buffer against stress; however, the effects of other types of self-esteem, such as relational self-esteem (RSE) and collective self-esteem (CSE), on stress have not been adequately explored. This study investigated the roles of PSE, RSE, and CSE in reducing stress response. The Rosenberg, Relational, and Collective Self-Esteem Scales were adopted to assess PSE, RSE, and CSE, respectively. Participants underwent an acute social stress paradigm, and their acute stress response was assessed using subjective stress reports and salivary cortisol levels. Chronic stress level was estimated using the Perceived Stress Scale and hair cortisol concentration. The results showed that PSE was negatively correlated with salivary cortisol response during acute social stress; however, no significant associations were found between any type of self-esteem and subjective stress reports. For chronic stress, all types of self-esteem were negatively associated with perceived stress level, but not with hair cortisol concentration. Further hierarchical regression analyses suggested that only PSE negatively predicted acute salivary cortisol response and perceived stress level. Overall, the findings suggest the essential role of PSE in predicting acute salivary cortisol responses and perceived stress.

Case Report: Application of Mixed Reality Combined With A Surgical Template for Precise Periapical Surgery.

Objective: The etiology of apical diseases is diverse, and most are due to incomplete root canal therapy. The common clinical manifestations include gingival abscess, fistula and bone destruction. The currently existing limitation of procedures is that surgeons cannot visually evaluate the surgical areas. We sought to combine mixed reality (MR) technology with a 3-dimensional (3D) printed surgical template to achieve visualization in apical surgery. Notably, no reports have described this application. Methods: We created visual 3D (V3D) files and transferred them into the HoloLens system. We explained the surgical therapy plan to the patient using a mixed reality head-mounted display (MR-HMD). Then, the 3D information was preliminarily matched with the operative area, and the optimal surgical approach was determined by combining this information with 3D surgical guide plate technology. Results: We successfully developed a suitable surgical workflow and confirmed the optimal surgical approach from the buccal side. We completely exposed the apical lesion and removed the inflammatory granulation tissue. Conclusion: We are the first group to use the MR technique in apical surgery. We integrated the MR technique with a 3D surgical template to successfully accomplish the surgery. Desirable outcomes using minimally invasive therapy could be achieved with the MR technique.