An Overview of Scaffolds and Biomaterials for Skin Expansion and Soft Tissue Regeneration: Insights on Zinc and Magnesium as New Potential Key Elements.

The utilization of materials in medical implants, serving as substitutes for non-functional biological structures, supporting damaged tissues, or reinforcing active organs, holds significant importance in modern healthcare, positively impacting the quality of life for millions of individuals worldwide. However, certain implants may only be required temporarily to aid in the healing process of diseased or injured tissues and tissue expansion. Biodegradable metals, including zinc (Zn), magnesium (Mg), iron, and others, present a new paradigm in the realm of implant materials. Ongoing research focuses on developing optimized materials that meet medical standards, encompassing controllable corrosion rates, sustained mechanical stability, and favorable biocompatibility. Achieving these objectives involves refining alloy compositions and tailoring processing techniques to carefully control microstructures and mechanical properties. Among the materials under investigation, Mg- and Zn-based biodegradable materials and their alloys demonstrate the ability to provide necessary support during tissue regeneration while gradually degrading over time. Furthermore, as essential elements in the human body, Mg and Zn offer additional benefits, including promoting wound healing, facilitating cell growth, and participating in gene generation while interacting with various vital biological functions. This review provides an overview of the physiological function and significance for human health of Mg and Zn and their usage as implants in tissue regeneration using tissue scaffolds. The scaffold qualities, such as biodegradation, mechanical characteristics, and biocompatibility, are also discussed.

Sublesional fat grafting leads to a temporary improvement of wound healing in chronic leg ulcers: A prospective, randomised clinical trial.

Chronic wounds remain a therapeutic and financial challenge for physicians and the health care systems. Innovative, inexpensive and effective treatment methods would be of immense value. The sublesional fat grafting could be such treatment, although effectiveness and safety have only been assessed in a few randomised clinical trials. The fat graft was obtained by liposuction, washed with the Coleman method and then injected sublesional and into the wound margins after surgical debridement. For the control group, saline solution was used instead of fat. The primary endpoint was to determine the wound size reduction in both groups. The wounds were measured preoperatively, intraoperatively and 3, 7, 21 and 60 days after the intervention. A p-value of <0.05 was considered significant. Furthermore, histology and microbiology of the wounds and pain were assessed. A temporary effect of the treatment was observed after 14 and 21 days. The wound size reduction was significantly larger in the intervention group, whereas after 60 days, no significant difference was detected between both groups. No adverse events could be reported and the pain level was almost equal in the control and intervention group. Sublesional fat grafting temporarily enhanced healing of chronic wounds. The procedure was safe and the pain level was low. Repeated interventions could lead to complete wound closure, which should be determined in future studies.

Ex Vivo Infection of Human Skin Models with Herpes Simplex Virus 1: Accessibility of the Receptor Nectin-1 during Formation or Impairment of Epidermal Barriers Is Restricted by Tight Junctions.

Herpes simplex virus 1 (HSV-1) must overcome epidermal barriers to reach its receptors on keratinocytes and initiate infection in human skin. The cell-adhesion molecule nectin-1, which is expressed in human epidermis, acts as an efficient receptor for HSV-1 but is not within reach of the virus upon exposure of human skin under nonpathological conditions. Atopic dermatitis skin, however, can provide an entry portal for HSV-1 emphasizing the role of impaired barrier functions. Here, we explored how epidermal barriers impact HSV-1 invasion in human epidermis and influence the accessibility of nectin-1 for the virus. Using human epidermal equivalents, we observed a correlation of the number of infected cells with tight-junction formation, suggesting that mature tight junctions prior to formation of the stratum corneum prevent viral access to nectin-1. Consequently, impaired epidermal barriers driven by Th2-inflammatory cytokines interleukin 4 (IL-4) and IL-13 as well as the genetic predisposition of nonlesional atopic dermatitis keratinocytes correlated with enhanced infection supporting the impact of functional tight junctions for preventing infection in human epidermis. Comparable to E-cadherin, nectin-1 was distributed throughout the epidermal layers and localized just underneath the tight-junctions. While nectin-1 was evenly distributed on primary human keratinocytes in culture, the receptor was enriched at lateral surfaces of basal and suprabasal cells during differentiation. Nectin-1 showed no major redistribution in the thickened atopic dermatitis and IL-4/IL-13-treated human epidermis in which HSV-1 can invade. However, nectin-1 localization toward tight junction components changed, suggesting that defective tight-junction barriers make nectin-1 accessible for HSV-1 which enables facilitated viral penetration. IMPORTANCE Herpes simplex virus 1 (HSV-1) is a widely distributed human pathogen which productively infects epithelia. The open question is which barriers of the highly protected epithelia must the virus overcome to reach its receptor nectin-1. Here, we used human epidermal equivalents to understand how physical barrier formation and nectin-1 distribution contribute to successful viral invasion. Inflammation-induced barrier defects led to facilitated viral penetration strengthening the role of functional tight-junctions in hindering viral access to nectin-1 that is localized just underneath tight junctions and distributed throughout all layers. We also found nectin-1 ubiquitously localized in the epidermis of atopic dermatitis and IL-4/IL-13-treated human skin implying that impaired tight-junctions in combination with a defective cornified layer allow the accessibility of nectin-1 to HSV-1. Our results support that successful invasion of HSV-1 in human skin relies on defective epidermal barriers, which not only include a dysfunctional cornified layer but also depend on impaired tight junctions.

Osteosynthesis-associated infection in maxillofacial surgery by bacterial biofilms: a retrospective cohort study of 11 years.

OBJECTIVES: The aim of this retrospective cohort study was to determine risk factors for osteosynthesis-associated infections (OAI) with subsequent necessity of implant removal in oral and maxillofacial surgery. MATERIALS AND METHODS: A total of 3937 records of patients who received either orthognathic, trauma, or reconstructive jaw surgery from 2009 to 2021 were screened for osteosynthetic material removal due to infection. Treatment-intervals, volume of applied osteosynthetic material, and respective surgical procedures were also assessed. Moreover, intraoperatively harvested microbial flora was cultured and subsequently identified by MALDI TOF. Bacteria were then screened for antibiotic resistance via VITEK system or, if necessary, via agar diffusion or epsilometer test. Data was analyzed utilizing SPSS statistical software. For statistical analysis of categorical variables, chi-square tests or Fisher exact tests were used. Continuous variables were compared via non-parametric tests. The level of significance for p-values was set at < 0.05. Descriptive analysis was also performed. RESULTS: The lower jaw was more prone to OAI than the mid face region. Larger volumes of osteosynthetic material led to significantly more OAI, resulting in reconstruction plates bearing the highest risk for OAI especially when compared to small-volume mini-plates frequently applied in trauma surgery. Among OAI associated with implant volumes smaller than 1500 mm3, the detection of Streptococcus spp., Prevotella spp., Staphylococcus spp., and Veillonella spp. was significantly elevated, whereas implant volumes larger than 1500 mm3 showed a significant increase of Enterococcus faecalis, Proteus mirabilis and Pseudomonas aeruginosa. High susceptibility rates (87.7-95.7%) were documented for 2nd- and 3rd-generation cephalosporines and piperacillin/tazobactam. CONCLUSION: High material load and lower jaw reconstruction bear the greatest risks for OAI. When working with large volume osteosynthetic implants, gram-negative pathogens must be considered when choosing an appropriate antibiotic regime. Suitable antibiotics include, e.g., piperacillin/tazobactam and 3rd-generation cephalosporines. CLINICAL RELEVANCE: Osteosynthetic material utilized in reconstructive procedures of the lower jaw may be colonized with drug-resistant biofilms.

Surgical side infections of the tracheostomy - A retrospective cohort study of patients with head and neck cancer in intensive care.

This study was conducted to reveal the relevant risk factors for surgical site infections (SSI) of the tracheostomy in ICU tracheostomy patients with oncologic history. Retrospectively, medical and ICU records of patients who received open tracheostomy in a uniform manner were investigated. Of 187 consecutive patients in total, patients with a peri/post-operative antibiotic prophylaxis (POABP) experienced significantly more Organ-Space SSI, whereas patients with a POABP developed less Superficial Incisional SSI and Deep Incisional SSI. Neck Dissection (p = 0.025), especially the more levels are included, and POABP (p = 0.005) have a significant impact on the occurrence of an SSI of the tracheostomy. Deep incisional SSI significantly prolonged a patient's dependency on a ventilator (p = 0.045, M = 3.92, SD = 4.718). The difference between Superficial Incisional, Deep Incisional and Organ-Space SSI should be taken in consideration regarding risk evaluation and treatment. Furthermore, a gram-negative facultative anaerobic biofilm should be taken into consideration in treatment options and thus an escalation regarding antibiotic treatment as a POABP. For fulminant SSI of the tracheostomy the use of piperacillin/tazobactam or 3rd generation cephalosporines or carbapenems is recommendable.

Herpes Simplex Virus 1 Can Bypass Impaired Epidermal Barriers upon Ex Vivo Infection of Skin from Atopic Dermatitis Patients.

To infect its human host, herpes simplex virus 1 (HSV-1) must overcome the protective barriers of skin and mucosa. Here, we addressed whether pathological skin conditions can facilitate viral entry via the skin surface and used ex vivo infection studies to explore viral invasion in atopic dermatitis (AD) skin characterized by disturbed barrier functions. Our focus was on the visualization of the onset of infection in single cells to determine the primary entry portals in the epidermis. After ex vivo infection of lesional AD skin, we observed infected cells in suprabasal layers indicating successful invasion in the epidermis via the skin surface which was never detected in control skin where only sample edges allowed viral access. The redistribution of filaggrin, loricrin, and tight-junction components in the lesional skin samples suggested multiple defective mechanical barriers. To dissect the parameters that contribute to HSV-1 invasion, we induced an AD-like phenotype by adding the Th2 cytokines interleukin 4 (IL-4) and IL-13 to healthy human skin samples. Strikingly, we detected infected cells in the epidermis, implying that the IL-4/IL-13-driven inflammation is sufficient to induce modifications allowing HSV-1 to penetrate the skin surface. In summary, not only did lesional AD skin facilitate HSV-1 penetration but IL-4/IL-13 responses alone allowed virus invasion. Our results suggest that the defective epidermal barriers of AD skin and the inflammation-induced altered barriers in healthy skin can make receptors accessible for HSV-1. IMPORTANCE Herpes simplex virus 1 (HSV-1) can target skin to establish primary infection in the epithelium. While the human skin provides effective barriers against viral invasion under healthy conditions, a prominent example of successful invasion is the disseminated HSV-1 infection in the skin of atopic dermatitis (AD) patients. AD is characterized by impaired epidermal barrier functions, chronic inflammation, and dysbiosis of skin microbiota. We addressed the initial invasion process of HSV-1 in atopic dermatitis skin to understand whether the physical barrier functions are sufficiently disturbed to allow the virus to invade skin and reach its receptors on skin cells. Our results demonstrate that HSV-1 can indeed penetrate and initiate infection in atopic dermatitis skin. Since treatment of skin with IL-4 and IL-13 already resulted in successful invasion, we assume that inflammation-induced barrier defects play an important role for the facilitated access of HSV-1 to its target cells.

Platelet-rich plasma (PRP) in oncological patients: long-term oncological outcome analysis of the treatment of subcutaneous venous access device scars in 89 breast cancer patients.

PURPOSE: Platelet-rich plasma (PRP) is widely used product, and meta-analyses showed this product to be beneficial when applied to a wound area. This study group has already demonstrated increased patient satisfaction and lower complication rates in breast cancer patients who received PRP after removal of their subcutaneous venous access device. This work is a follow-up analysis focusing on oncologic safety. Currently, there is no long-term data on the use of PRP products in cancer patients available yet. METHODS: Between the years 2012-2016, venous access device removal was supported with the application of Arthrex ACP® (Autologous Conditioned Plasma)-a PRP product to improve the wound-healing process. All surgeries were performed in the breast cancer center of the municipal hospital of Cologne, Holweide, Germany. 35 patients received an application of Arthrex ACP® after port removal compared to the control group of 54 patients. Endpoints were local recurrence-free, distant recurrence-free as well as overall survival. RESULTS: Median follow-up was 45 months. No (0) adverse events were shown for cancer recurrence within the subcutaneous venous access device scar area. Thus, there seems to be no local oncogenic potential of the PRP product. All other endpoints as well as any-cause death numerically favor PRP use. CONCLUSION: PRP products such as Arthrex ACP® seem to be oncological inert when applied after removal of subcutaneous access devices. This is the first study providing long-term data about overall survival, distant recurrence-free and local recurrence-free survival after applying PRP in high-risk cancer patients.

Development and validation of a parametric human mandible model to determine internal stresses for the future design optimization of maxillofacial implants.

Large segmental mandible bone defects still represent a challenge for endogenous regeneration. Despite the bone's capacity to heal in many clinical situations, bone defects over a critical size do not heal spontaneously. An emerging treatment of critically sized mandibular defects is the implantation of individually manufactured scaffolds consisting of biodegradable magnesium alloys. Biomedical engineers faced the challenge of developing a scaffold structure that not only provides sufficient stability, but also stimulates and promotes bone growth while considering the degradation of the magnesium alloy. The porosity of the scaffold must also support bone ingrowth and neovascularization. For an optimal design and subsequent structural optimization knowledge of external load cases is essential. However, currently the muscle and joint forces of the mandible cannot be measured directly. The aim of our study was therefore the development of a parametric human mandible model to determine the relevant boundary conditions for the subsequent structural optimization of individual jawbone implants. Using a model-based approach, determining the essential external load of the mandible as a function of the age and sex of a patient individually and the realistic simulation of the mechanical stress for patient-specific loads and anatomies has been realized. The developed model is successfully validated by evaluating the deformations and stresses of the lower jaw of a possible patient and comparing them with the results of dental research. Based on the results of the modelling, in a subsequent optimization process section forces at the interface between the bone tissue and jawbone implant can be determined and used to optimize the design of the jawbone implant.

Correlation analysis of resected breast tissue and implant volume after mastectomy and its association with breast density.

BACKGROUND: The current methods for calculating the ideal implant volume for breast reconstruction are based on pre- or intraoperative volume measurements of the existing breast volume and do not take into account the individual breast density of the woman. This study aims is to identify objective parameters that can help to improve the optimal implant selection. MATERIALS AND METHODS: This retrospective analysis includes 198 breast cancer patients who underwent mastectomy. Breast densities (ACR) measured in mammography and MRI were compared with the removed breast tissue weight and volume of the implants used. In addition, the resected weight was compared directly with the implant volume to calculate a mathematical function. RESULTS: There was no significant correlation between the ACR values and the resected weights [correlation coefficient: mammography:- 0.117 (p = 0.176), MRI - 0.033 (p = 0.756)]. A negative correlation between the implant volumes and both imaging methods could be demonstrated [correlation coefficient: mammography - 0.268; p = 0.002; MRI was - 0.200 (p = 0.055)]. A highly significant correlation between the resected weights and the implant volumes (correlation coefficient 0.744; p < 0.001) was observed. This correlation corresponds to a power function (y = 34.71 x0.39), in which any resected weight can be used for the variable x to calculate the implant volume. CONCLUSION: We were able to show that there is a significant correlation between the resected breast tissue and the implant volume. With our novel potency function, the appropriate implant volume can be calculated for any resected weight making it easier for the surgeon to choose a fitting implant in a simple and more objective manner.

Preoperative Perforator Mapping in DIEP Flaps for Breast Reconstruction. The Impact of New Contrast-Enhanced Ultrasound Techniques.

Deep inferior epigastric artery flaps (DIEP) represent the gold standard of autologous breast reconstruction. Due to significant variations in vascular anatomy, preoperative perforator mapping (PM) is mandatory in order to ensure the presence of a sufficient perforator within the flap. In this regard, CT angiography (CTA) is currently the method of choice. Therefore, we investigated the value of contrast-enhanced ultrasound (CEUS) techniques for preoperative PM in comparison to CTA. Patients underwent PM, utilizing both CTA and CEUS techniques. Documentation included the course of the vascular pedicle through the rectus muscle (M), fascial penetration (F), the subcutaneous plexus (P) and the skin point (SP) on either side of the abdomen. Thus, contrast-enhanced B-Flow (BCEUS), B-Flow ultrasound (BUS), CEUS, color Doppler ultrasound (CDUS) and CTA were evaluated in terms of the diagnostic consistency and effectiveness of PM. Precision (∆L) was then calculated in relation to the actual intraoperative location. Statistical analysis included Kruskall-Wallis, Levene and Bonferroni tests, as well as Spearman correlations. A total of 39 DIEP flaps were analyzed. Only CTA (∆L = 2.85 mm) and BCEUS (∆L = 4.57 mm) enabled complete PM, also including P and SP, whereas CDUS, CEUS and BUS enabled clear PM throughout M and F only. Regarding the number of detected perforators, PM techniques are ranked from high to low as follows: CTA, BCEUS, BUS, CEUS and CDUS. CTA and BCEUS showed sufficient diagnostic consistency for SP, P and F, while CDUS and CTA had a superior performance for M. BCEUS offers precise image-controlled surface tags and dynamic information for PM without imposing radiation and may, therefore, be considered a feasible add-on or alternative to CTA. However, BCEUS requires an experienced examiner and is more time-consuming.

#facialtraumasurgery: Educational Content of Instagram as a Social Media Source for Facial Trauma Surgery.

ABSTRACT: With an uprising influence of social media platforms like Instagram during the last decade, medical and healthcare related posts have accumulated majorly. In particular the head and face characterizes and signifies each individual's human character, which may be the reason why numerous posts are shared on social media platforms. The purpose of this investigation was to assess the content associated with facial trauma surgery and evaluate its educational quality.The authors performed a retrospective investigation on 550 Instagram posts by #facialtraumasurgery due to number of "likes," comments, type of post, language, its purpose, and source. Furthermore, posts were evaluated due to their educational quality by 3 examiners of different educational levels.The majority of posts showed 0 to 50 "likes" and 0 to 5 comments in English language. The major post type were single photographs (289; 52.5%), multiple photographs (188; 34.2%), videos (73; 13.3%) and predominantly case reports (233; 42.4%). The source was 322 (58.5%) posts by surgeons, followed by 185 (33.6%) clinic posts. Only 10% to 18% of the posts were rated "excellent." Interrater reliability between all 3 examiners presented a high concordance with 89% (P = 0.000).Our study presents an analysis of quantity and quality of social media content according to facial trauma surgery. It supports the deduction that most of the content on Instagram is shared by patients and unclear sources and thus is limited informative. Nevertheless, influence of social media on medical information is increasing and practitioners have to face its effect on their patients.

Ex Vivo Infection of Human Skin with Herpes Simplex Virus 1 Reveals Mechanical Wounds as Insufficient Entry Portals via the Skin Surface.

Herpes simplex virus 1 (HSV-1) enters its human host via the skin and mucosa. The open question is how the virus invades this highly protective tissue in vivo to approach its receptors in the epidermis and initiate infection. Here, we performed ex vivo infection studies in human skin to investigate how susceptible the epidermis and dermis are to HSV-1 and whether wounding facilitates viral invasion. Upon ex vivo infection of complete skin, only sample edges with integrity loss demonstrated infected cells. After removal of the dermis, HSV-1 efficiently invaded the basal layer of the epidermis and, from there, gained access to suprabasal layers. This finding supports a high susceptibility of all epidermal layers which correlated with the surface expression of the receptors nectin-1 and herpesvirus entry mediator (HVEM). In contrast, only single infected cells were detected in the separated dermis, where minor expression of the receptors was found. Interestingly, after wounding, nearly no infection of the epidermis was observed via the skin surface. However, if the wounding of the skin samples led to breaks through the dermis, HSV-1 infected mainly keratinocytes via the damaged dermal layer. The application of latex beads revealed only occasional entry via the wounded dermis; however, it facilitated penetration via the wounded skin surface. Thus, we suggest that although the wounded human skin surface allows particle penetration, the skin still provides barriers that prevent HSV-1 from reaching its receptors. IMPORTANCE The human pathogen herpes simplex virus 1 (HSV-1) invades its host via the skin and mucosa, which leads to primary infection of the epithelium. As the various epithelial barriers effectively protect the tissue against viral invasion, successful infection most likely depends on tissue damage. We addressed the initial invasion process in human skin by ex vivo infection to understand how HSV-1 overcomes physical skin barriers and reaches its receptors to enter skin cells. Our results demonstrate that intact skin samples allow viral access only from the edges, while the epidermis is highly susceptible once the basal epidermal layer serves as an initial entry portal. Surprisingly, mechanical wounding did not facilitate HSV-1 entry via the skin surface, although latex beads still penetrated via the lesions. Our results imply that successful invasion of HSV-1 depends on how well the virus can reach its receptors, which was not accomplished by skin lesions under ex vivo conditions.

An Innovative Approach for Preoperative Perforator Flap Planning Using Contrast-enhanced B-flow Imaging.

Precise perforator mapping of the epifascial and subcutaneous course of the perforator flaps, including the precise detection of the skin point, is mandatory for successful preoperative flap design and planning of supramicrosurgery. We investigated the effectiveness of contrast-enhanced B-flow (BCEUS) imaging for perforator mapping and preoperative perforator flap planning and compared it with B-flow ultrasound, contrast-enhanced ultrasound, and color Doppler ultrasound. Sixteen patients who received an individualized perforator flap reconstruction were included in the study. Preoperative perforator mapping includes the following structures: subfascial course of the pedicle, fascial penetration point, subcutaneous course (epifascial and subcutaneous), and perforator skin point. The precision of the preoperative perforator mapping was analyzed for color Doppler ultrasound, contrast-enhanced ultrasound, B-flow ultrasound, and BCEUS. Each technique was able to precisely display the subfascial course of the vascular pedicle, including the fascial penetration point. However, only BCEUS enabled precise mapping of the epifascial and subcutaneous (suprafascial) course, including the skin point of the perforators with a clear delineation. Precise knowledge of the suprafascial course of the perforators is mandatory for successful supermicrosurgery and perforator flap planning. BCEUS imaging facilitates full perforator mapping, which improves the safety of flap harvesting. However, BCEUS is technically demanding and requires an experienced sonographer.

Influence of surface condition on the degradation behaviour and biocompatibility of additively manufactured WE43.

The further development of future Magnesium based biodegradable implants must consider not only the freedom of design, but also comprise implant volume reduction, as both aspects are crucial for the development of higher functionalised implants, such as plate systems or scaffold grafts in bone replacement therapy. As conventional manufacturing methods such as turning and milling are often accompanied by limitations concerning implant design and functionality, the process of laser powder bed fusion (LPBF) specifically for Magnesium alloys was recently introduced. In addition, the control of the degradation rate remains a key aspect regarding biodegradable implants. Recent studies focusing on the degradation behaviour of additively manufactured Magnesium scaffolds disclosed additional intricacies when compared to conventionally manufactured Magnesium parts, as a notably larger surface area was exposed to the immersion medium and scaffold struts degraded non-uniformly. Moreover, chemical etching as post processing technique is applied to remove sintered powder particles from the surface, altering surface chemistry. In this study, cylindrical Magnesium specimens were manufactured by LPBF and surfaces were consecutively modified by phosphoric etching and machining. Degradation behaviour and biocompatibility were then investigated, revealing that etched samples exhibited the overall lowest degradation rates, but experienced large pit formation, while the reduction of surface roughness resulted in a delay of degradation.

Towards a flexible electrochemical biosensor fabricated from biocompatible Bombyx mori silk.

In modern days, there is an increasing relevance of and demand for flexible and biocompatible sensors for in-vivo and epidermal applications. One promising strategy is the implementation of biological (natural) polymers, which offer new opportunities for flexible biosensor devices due to their high biocompatibility and adjustable biodegradability. As a proof-of-concept experiment, a biosensor was fabricated by combining thin- (for Pt working- and counter electrode) and thick-film (for Ag/AgCl quasi-reference electrode) technologies: The biosensor consists of a fully bio-based and biodegradable fibroin substrate derived from silk fibroin of the silkworm Bombyx mori combined with immobilized enzyme glucose oxidase. The flexible glucose biosensor is encapsulated by a biocompatible silicon rubber which is certificated for a safe use onto human skin. Characterization of the sensor set-up is exemplarily demonstrated by glucose measurements in buffer and Ringer's solution, while the stability of the quasi-reference electrode has been investigated versus a commercial Ag/AgCl reference electrode. Repeated bending studies validated the mechanical properties of the electrode structures. The cross-sensitivity of the biosensor against ascorbic acid, noradrenaline and adrenaline was investigated, too. Additionally, biocompatibility and degradation tests of the silk fibroin with and without thin-film platinum electrodes were carried out.

Comparison of two established 2D staging techniques to their appliance in 3D cone beam computer-tomography for dental age estimation.

For medicolegal purposes, orthodontic or orthognathic treatment various stomatological staging technique for age estimation with appliance of conventional radiographic images have been published. It remains uninvestigated if cone beam computer-tomography delivers comparable staging results to the conventional radiographic stages of third molar analysis. We conducted a retrospective cross-sectional study of 312 patients aged 13-21 years. Dental age estimation staging technique, introduced by Nolla and Demirjian, were applied on the left lower third molar imaged by conventional panoramic radiographs and cone beam computer-tomography. It was investigated if 2D and 3D imaging presented different staging results for dental age estimation. In 21% the Demirjian's staging differed by a single stage between 2 and 3D images. The greatest congruence (87%) between 2 and 3D images was revealed for stage 7 (G). In contrary, stage 5 (E) presented the lowest level of congruence with 47.4%. The categorization of Nolla revealed divergences in staging for than two categorical variables in Nolla's stages 3, 4, 5 and 6. In general, the analysis of the data displayed the divergence for Nolla's stages 4-8. The staging results for 2D and 3D imaging in accordance to the rules of Nolla and Demirjian showed significant differences. Individuals of 18 years may present immature third molars, thus merely an immature third molar cannot reject legal majority. Nolla's and Demirjian's 2D and 3D imaging present significantly different staging results.

Microstructure, mechanical properties, corrosion resistance and cytocompatibility of WE43 Mg alloy scaffolds fabricated by laser powder bed fusion for biomedical applications.

Open-porous scaffolds of WE43 Mg alloy with a body-center cubic cell pattern were manufactured by laser powder bed fusion with different strut diameters. The geometry of the unit cells was adequately reproduced during additive manufacturing and the porosity within the struts was minimized. The microstructure of the scaffolds was modified by means of thermal solution and ageing heat treatments and was analysed in detail by means of X-ray microtomography, optical, scanning and transmission electron microscopy. Moreover, the corrosion rates and the mechanical properties of the scaffolds were measured as a function of the strut diameter and metallurgical condition. The microstructure of the as-printed scaffolds contained a mixture of Y-rich oxide particles and Rare Earth-rich intermetallic precipitates. The latter could be modified by heat treatments. The lowest corrosion rates of 2-3 mm/year were found in the as-printed and solution treated scaffolds and they could be reduced to ~0.1 mm/year by surface treatments using plasma electrolytic oxidation. The mechanical properties of the scaffolds improved with the strut diameter: the yield strength increased from 8 to 40 MPa and the elastic modulus improved from 0.2 to 0.8 GPa when the strut diameter increased from 275 µm to 800 µm. Nevertheless, the strength of the scaffolds without plasma electrolytic oxidation treatment decreased rapidly when immersed in simulated body fluid. In vitro bicompatibility tests showed surface treatments by plasma electrolytic oxidation were necessary to ensure cell proliferation in scaffolds with high surface-to-volume ratio.

Influence of the Casting Concentration on the Mechanical and Optical Properties of FA/CaCl2-Derived Silk Fibroin Membranes.

In this study, we describe the manufacturing and characterization of silk fibroin membranes derived from the silkworm Bombyx mori. To date, the dissolution process used in this study has only been researched to a limited extent, although it entails various potential advantages, such as reduced expenses and the absence of toxic chemicals in comparison to other conventional techniques. Therefore, the aim of this study was to determine the influence of different fibroin concentrations on the process output and resulting membrane properties. Casted membranes were thus characterized with regard to their mechanical, structural and optical assets via tensile testing, SEM, light microscopy and spectrophotometry. Cytotoxicity was evaluated using BrdU, XTT, and LDH assays, followed by live-dead staining. The formic acid (FA) dissolution method was proven to be suitable for the manufacturing of transparent and mechanically stable membranes. The fibroin concentration affects both thickness and transparency of the membranes. The membranes did not exhibit any signs of cytotoxicity. When compared to other current scientific and technical benchmarks, the manufactured membranes displayed promising potential for various biomedical applications. Further research is nevertheless necessary to improve reproducible manufacturing, including a more uniform thickness, less impurity and physiological pH within the membranes.

Oral recipient site infections in reconstructive surgery - impact of the graft itself and the perioperative antibiosis.

OBJECTIVES: This study was designed to assess the influence of peri/post-operative antibiotic prophylaxis (POABP) and the reconstructive graft itself on recipient sites infections in head and neck surgery. MATERIALS AND METHODS: In this retrospective cohort study, 322 consecutive patients with reconstructive surgery were investigated. The primary objective was to analyze the differences of commonly applied reconstructive grafts on the occurrence of oral recipient site infections. Moreover, differences of POABP regimes (namely: ampicillin/sulbactam, 2nd generation cephalosporins, clindamycin) and antibiotic alternatives were investigated. In addition, patients' length of in-hospital stay was analyzed in regard to reconstructive graft and POABP regime. RESULTS: The free radial forearm flap and split-thickness skin graft presented significantly less recipient site infections and shorter length of in-hospital stays (LOS) in comparison to further six reconstructive technique with pedicled tissue transfer or bone transfers. LOS was significantly shorter for patients with ampicillin/sulbactam than with 2nd generation cephalosporins as POABP. 91% of the harvested pathogens (n=193) were susceptible to the combination of 2nd and 3rd generation cephalosporins. Secondly, 92 out 113 (81%) harvested pathogens presented susceptibility to moxifloxacin. CONCLUSION: Smaller tissue transfers are less prone to infections of the recipient site and present low LOS. For an POABP regime, the combination of 2nd and 3rd generation cephalosporins presents substantial results in recipient site infections. In cases of allergy, potential pathogens show adequate susceptibility to moxifloxacin. CLINICAL RELEVANCE: A combination of 2nd and 3rd generation cephalosporins may be used to prevent recipient sites in head and neck surgery.

Incidental findings on craniomaxillofacial cone beam computed tomography in orthodontic patients.

PURPOSE: Cone beam computed tomography (CBCT) in orthodontics is increasingly used for detecting impacted or ectopic teeth or for orthognathic and cleft lip and palate treatment. Incidental findings (IFs) are frequently encountered and often relevant. The aim of this study was to detect the prevalence of relevant pathologies on CBCT scans of orthodontic patients. METHODS: Over a 6-year period, incidental imaging findings were analyzed in 345 CBCT scans (181 men; 164 women; age 16.3 ± 8.4 years), and subdivided into dental (Group 1), skeletal (Group 2), sinunasal (Group 3), and infrequent other pathologies (Group 4). RESULTS: A total of 502 IFs were detected in 345 patients (1.4 IFs per patient, on average). Most IFs were found in Group 1 (358 IFs; 71.3%), followed by Group 2 (129 IFs; 25.7%), Group 3 (14 IFs; 2.8%), and Group 4 (1 IF; 0.2%). There were 119 (34.5%) patients with a missing wisdom tooth, 94 (27.3%) with dental aplasia, 71 (20.6%) with dislocations, 33 (9.6%) with partial opacifications, and 27 (7.8%) with signs of sinusitis. CONCLUSIONS: This study found that IFs in orthodontic CBCT scans are frequently encountered, even in younger orthodontic patients. When interpreting CBCT scans, orthodontists should be aware of potential relevant IFs that may require further investigation, change patients' treatment or affect their quality of life.