Virtual blebbistatin: A robust and rapid software approach to motion artifact removal in optical mapping of cardiomyocytes.

Fluorescent reporters of cardiac electrophysiology provide valuable information on heart cell and tissue function. However, motion artifacts caused by cardiac muscle contraction interfere with accurate measurement of fluorescence signals. Although drugs such as blebbistatin can be applied to stop cardiac tissue from contracting by uncoupling calcium-contraction, their usage prevents the study of excitation-contraction coupling and, as we show, impacts cellular structure. We therefore developed a robust method to remove motion computationally from images of contracting cardiac muscle and to map fluorescent reporters of cardiac electrophysiological activity onto images of undeformed tissue. When validated on cardiomyocytes derived from human induced pluripotent stem cells (iPSCs), in both monolayers and engineered tissues, the method enabled efficient and robust reduction of motion artifact. As with pharmacologic approaches using blebbistatin for motion removal, our algorithm improved the accuracy of optical mapping, as demonstrated by spatial maps of calcium transient decay. However, unlike pharmacologic motion removal, our computational approach allowed direct analysis of calcium-contraction coupling. Results revealed calcium-contraction coupling to be more uniform across cells within engineered tissues than across cells in monolayer culture. The algorithm shows promise as a robust and accurate tool for optical mapping studies of excitation-contraction coupling in heart tissue.

Apolipoprotein E4 has extensive conformational heterogeneity in lipid-free and lipid-bound forms.

The ε4-allele variant of apolipoprotein E (ApoE4) is the strongest genetic risk factor for Alzheimer's disease, although it only differs from its neutral counterpart ApoE3 by a single amino acid substitution. While ApoE4 influences the formation of plaques and neurofibrillary tangles, the structural determinants of pathogenicity remain undetermined due to limited structural information. Previous studies have led to conflicting models of the C-terminal region positioning with respect to the N-terminal domain across isoforms largely because the data are potentially confounded by the presence of heterogeneous oligomers. Here, we apply a combination of single-molecule spectroscopy and molecular dynamics simulations to construct an atomically detailed model of monomeric ApoE4 and probe the effect of lipid association. Importantly, our approach overcomes previous limitations by allowing us to work at picomolar concentrations where only the monomer is present. Our data reveal that ApoE4 is far more disordered and extended than previously thought and retains significant conformational heterogeneity after binding lipids. Comparing the proximity of the N- and C-terminal domains across the three major isoforms (ApoE4, ApoE3, and ApoE2) suggests that all maintain heterogeneous conformations in their monomeric form, with ApoE2 adopting a slightly more compact ensemble. Overall, these data provide a foundation for understanding how ApoE4 differs from nonpathogenic and protective variants of the protein.

Correction of multiple-blinking artifacts in photoactivated localization microscopy.

Photoactivated localization microscopy (PALM) produces an array of localization coordinates by means of photoactivatable fluorescent proteins. However, observations are subject to fluorophore multiple blinking and each protein is included in the dataset an unknown number of times at different positions, due to localization error. This causes artificial clustering to be observed in the data. We present a 'model-based correction' (MBC) workflow using calibration-free estimation of blinking dynamics and model-based clustering to produce a corrected set of localization coordinates representing the true underlying fluorophore locations with enhanced localization precision, outperforming the state of the art. The corrected data can be reliably tested for spatial randomness or analyzed by other clustering approaches, and descriptors such as the absolute number of fluorophores per cluster are now quantifiable, which we validate with simulated data and experimental data with known ground truth. Using MBC, we confirm that the adapter protein, the linker for activation of T cells, is clustered at the T cell immunological synapse.

Drug-Polymer Nanodroplet Formation and Morphology Drive Solubility Enhancement of GDC-0810.

Nanodroplet formation is important to achieve supersaturation of active pharmaceutical ingredients (APIs) in an amorphous solid dispersion. The aim of the current study was to explore how polymer composition, architecture, molar mass, and surfactant concentration affect polymer-drug nanodroplet morphology with the breast cancer API, GDC-0810. The impact of nanodroplet size and morphology on dissolution efficacy and drug loading capacity was explored using polarized light microscopy, dynamic light scattering, and cryogenic transmission electron microscopy. Poly(N-isopropylacrylamide-stat-N,N-dimethylacrylamide) (PND) was synthesized as two linear derivatives and two bottlebrush derivatives with carboxylated or PEGylated end-groups. Hydroxypropyl methylcellulose acetate succinate grade MF (HPMCAS-MF) and poly(vinylpyrrolidone-co-vinyl acetate) (PVPVA) were included as commercial polymer controls. We report the first copolymerization synthesis of a PVPVA bottlebrush copolymer, which was the highest performing excipient in this study, maintaining 688 µg/mL GDC-0810 concentration at 60 wt % drug loading. This is likely due to strong polymer-drug noncovalent interactions and the compaction of GDC-0810 along the PVPVA bottlebrush backbone. Overall, it was observed that the most effective formulations had a hydrodynamic radius less than 25 nm with tightly compacted nanodroplet morphologies.

Practice-Oriented Research: An Introduction to New Developments and Future Directions.

Aimed at understanding and improving psychological therapies as they are conducted in clinical routine, practice-oriented research (POR) is now a well-established approach to the scientific foundations of mental health care services. Resting on the accumulation of a wide range of practice-based evidence related to treatment outcome and process, as well as factors associated with the participants of psychotherapy and its context, POR is ripe for new developments - regarding what to investigate and how to investigate it. This paper is the introduction of a series devoted to recent advances and future directions of POR as their pertained to routine outcome monitoring, technologies and artificial intelligence, the integration of constructs and methods from program evaluation and implementation science, and the investigation of populations with limited financial resources across various regions of the world. The series also includes commentaries from two leaders of POR.

The Importance of Conducting Practice-oriented Research with Underserved Populations.

There has been a growing emphasis on dissemination of empirically supported treatments. Dissemination, however, should not be restricted to treatment. It can and, in the spirit of the scientific-practitioner model, should also involve research. Because it focuses on the investigation of clinical routine as it takes place in local settings and because it can involve the collaboration of several stakeholders, practice-oriented research (POR) can be viewed as an optimal research method to be disseminated. POR has the potential of addressing particularly relevant gaps of knowledge and action when implemented in regions of the world that have limited resources for or experiences with empirical research, and/or in clinical settings that are serving clinical populations who are not typically receiving optimal mental care services - specifically, individuals in rural and inner cities that have limited economic and social resources. The establishment and maintenance of POR in such regions and/or settings, however, come with specific obstacles and challenges. Integrating the experiences acquired from research conducted in various continents (Africa, Europe, Latin America, and North America), the goal of this paper is to describe some of these challenges, strategies that have been implemented to address them, as well as new possible directions to facilitate the creation and growth of POR. It also describes how these challenges and ways to deal with them can provide helpful lessons for already existing POR infrastructures.

One-Pot Syntheses of Substituted Oxazoles and Imidazoles from the Isocyanide Asmic.

Substituted oxazoles and imidazoles are synthesized in one pot from the isocyanide building block Asmic (anisylsulfanylmethyl isocyanide), an alkyl halide, and an acid chloride or nitrile, respectively. The modular assembly employs sequential deprotonation-alkylation and deprotonation-acylation or imination of Asmic, followed by an unusual carbon-sulfur bond cleavage to construct the azole. The strategy is robust, highly efficient, and affords C4-C5 disubstituted oxazoles or imidazoles in a single operation.

Helicobacter pylori World Gastroenterology Organization Global Guideline.

Helicobacter pylori remains a major health problem worldwide, causing considerable morbidity and mortality due to peptic ulcer disease and gastric cancer. The burden of disease falls disproportionally on less well-resourced populations. As with most infectious diseases, the largest impact on reducing this burden comes from improvement in socioeconomic status, which interrupts transmission. This has been observed in many regions of the world, but the prevalence of infection remains high in many regions where improvements in living standards are slow to occur. Meanwhile, the optimal clinical management and treatment pathways remain unsettled and are evolving with changing antimicrobial resistance patterns. Despite decades of research and clinical practice, major challenges remain. The quest for the most effective, safe, and simple therapy remains the major issue for clinicians. The search for an effective vaccine appears to be elusive still. Clinical guidelines do not infrequently proffer discordant advice. A major challenge for guidelines is for relevance across a variety of populations with a varying spectrum of disease, antimicrobial resistance rates, and vastly different resources. As local factors are central to determining the impact and management strategies for H. pylori infection, it is important that pathways are based on the best available local knowledge rather than solely extrapolating from guidelines formulated in other regions, which may be less applicable. To this end, this revision of the World Gastroenterology Organisation (WGO) H. pylori guideline uses a "Cascades" approach that seeks to summarize the principles of management and offer advice for pragmatic, relevant and achievable diagnostic and treatment pathways based on established key treatment principles and using local knowledge and available resources to guide regional practice.

Does Emotional State Improve Following Temporomandibular Joint Total Joint Replacement?

BACKGROUND: Temporomandibular joint total joint replacement (TMJTJR) offers patients the opportunity for improved function and reduced pain. TMJTJR also has the potential to affect a patient's emotions in a positive or negative manner. PURPOSE: The purpose of this study was to evaluate changes in emotional state for subjects undergoing TMJTJR. STUDY DESIGN, SETTING, SAMPLE: The authors implemented a retrospective cohort study. Subjects who received TMJTJR were identified from the TMJ Inter Network, which is a study group comprising more than 130 temporomandibular joint surgeons. Subjects between the ages of 18 and 65 years with complete medical records and pre/post TMJTJR video/audio recordings were enrolled in the study. PREDICTOR VARIABLE: The predictor variable was time (preoperative and postoperative). MAIN OUTCOME VARIABLES: The primary outcome variable is change in the emotional state. All subjects had preoperative (T0) recorded interview as well as a postoperative (T1) interview at 3 to 6 months. The eight-category emotional state was classified as neutral, happy, sad, angry, fearful, disgusted, surprised, and bored. The three-category emotional state was classified as neutral, positive, and negative. The emotional state was measured using artificial intelligence at T0 and T1. The secondary outcome variable was pain score and maximal interincisal opening. COVARIATES: The covariates are gender, age, diagnosis, prosthetic side, TMJTJR design, and TMJTJR type. ANALYSES: The relationship between emotional state change and covariates was examined using both the χ2 test and the Kruskal-Wallis H test. The significance of the change in categorical data after surgery was examined using the McNemar-Bowker test. P values < .05 were considered statistically significant. RESULTS: Thirty-three subjects were included in the study. The mean age was 30.09 ± 8.69 with 15 males (45%) and 18 females (55%). The percentage of subjects with preoperative neutral, happy, sad, angry, and fearful emotional states was 24, 15, 24, 9, and 27%, respectively. The percentage of subjects with postoperative neutral, happy, sad, angry, and fearful emotional states was 21, 39, 21, 12, and 6%, respectively. The change in emotional state was statistically significant (P = .037). There was no statistically significant relationship between covariates and emotional state changes (P > .05). CONCLUSION: According to the assessment of artificial intelligence, TMJTJR improves the emotional state of patients.

Baseline overly accommodating interpersonal problems in relation to parsed alliance-outcome associations in cognitive behavioral therapy for generalized anxiety disorder.

Given its interpersonal underpinnings, relational factors may be salient in psychotherapy for generalized anxiety disorder (GAD). Supporting this point, research has indicated a positive total alliance-improvement correlation in cognitive behavioral therapy (CBT) for GAD. However, less research has disaggregated this correlation into within- and between-patient components, or examined theory-informed ways in which patient characteristics influence to these components. Thus, we first investigated parsed alliance-outcome associations in CBT for GAD. Second, consistent with theory that alliance may represent a direct interpersonal change correlate, we tested whether within-patient alliance improvements were especially therapeutic for patients with higher levels of an interpersonal problem prototypical of GAD-over accommodation. Also, consistent with theory that between-patient differences in overall alliance may be influenced by patients' preexisting relational characteristics, we tested whether more overly accommodating patients reported poorer average alliances that, in turn, related to worse outcomes.Sixty-nine patients received variants of CBT. Patients rated over accommodation at baseline, and alliance and outcome across treatment.As hypothesized, within-patient alliance improvements correlated with subsequent anxiety reduction, and this association was stronger for more overly accommodating patients. All between-patient associations were nonsignificant.Results help clarify the nuanced role of alliance in CBT for GAD.

Reconstructing dropout: Building from multiple definitions, therapist effects, and center effects.

Objective: The literature regarding dropout from psychotherapy has suffered from issues of diverse operationalization of the construct. Some have called for a more uniform definition to aid in generalization across research; this study aimed to assess the viability of such a definition by examining the rate of occurrence for three distinct definitions simultaneously. In addition, therapist and center level variances are explored to further understand the differences between definitions.Method: We compared the prevalence rates and overlap of three distinct operationalizations of dropout (based on last session attendance, therapist judgment, and symptom change) using data gathered from a national practice research network (N = 2977). Higher-order therapist and center-level effects were assessed for each definition.Results: There was very little overlap among definitions, with less than one percent of clients simultaneously meeting criteria for all three definitions. Additionally, therapist and center effects were found for each definition, especially notable for therapist-rated and last-session attendance definitions of dropout.Conclusion: Rather than a singular definition of dropout, these results instead suggest that multiple, specific, and unique definitions more accurately depict clinical reality, and future research might benefit from uncovering predictors of different "classes" of dropouts and examining the different practices of therapists and centers.

Therapeutic alliance and clinical outcomes in teletherapy and in-person psychotherapy: A noninferiority study during the COVID-19 pandemic.

OBJECTIVE: The current study aimed to inform the varied and limited research on clinical variables in the context of teletherapy. Questions remain about the comparative quality of therapeutic alliance and clinical outcome in the context of teletherapy compared to in-person treatment. METHODS: We utilized a cohort design and a noninferiority statistical approach to study a large, matched sample of clients who reported therapeutic alliance as well as psychological distress before every session as part of routine clinical practice at a university counseling center. A cohort of 479 clients undergoing teletherapy after the emergence of the COVID-19 pandemic was compared to a cohort of 479 clients receiving in-person treatment before the onset of the pandemic. Tests of noninferiority were conducted to investigate the absence of meaningful differences between the two modalities of service delivery. Client characteristics were also examined as moderators of the association between modality and alliance or outcome. RESULTS: Clients receiving teletherapy showed noninferior alliance and clinical outcome when compared to clients receiving in-person psychotherapy. A significant main effect on alliance was found with regard to race and ethnicity. A significant main effect on outcome was found with regard to international student status. Significant interactions on alliance were found between cohort and current financial stress. CONCLUSIONS: Study findings support the continued use of teletherapy by demonstrating commensurate clinical process and outcome. Yet, it will be important for providers to be aware of existing mental health disparities that continue to accompany psychotherapy - in person and via teletherapy. Results and findings are discussed in terms of research and clinical implications. Future directions for researching teletherapy as a viable treatment delivery method are also discussed.

Therapeutic techniques and session impact: A practice-research network study in private practice.

Objective: This study investigated the relationship between therapeutic techniques and session impact, by examining the replicability of findings observed in a university-based training clinic (Boswell et al., 2010) in another practice-oriented setting: private practice.Method: N = 8 therapists completed session-level assessments of their technique use for N = 38 clients. The same client sample completed session-level assessments of session outcome. Technique-outcome associations were examined with multilevel models.Results: As in Boswell et al., common factors were associated with positive session impact. For clients who received higher average common factor techniques (relative to their own therapist's caseload), session impact was the poorest in sessions with higher behavioral change techniques use (relative to the client's own average). Moreover, clients with the lowest average common factor techniques (relative to their therapist's caseload) reported better session impact in sessions that involved a higher degree of session-level behavioral change techniques (relative to their own average).Conclusion: In line with Boswell et al., therapists should be mindful of the consistency of their routine technique use between- and within-clients, and this can be aided through collection of their own practice-oriented data.

Proton motive force underpins respiration-mediated potentiation of aminoglycoside lethality in pathogenic Escherichia coli.

It is well known that loss of aerobic respiration in Gram-negative bacteria can diminish the efficacy of a variety of bactericidal antibiotics, which has lead to subsequent demonstrations that the formation of reactive oxygen species (ROS) and the proton motive force (PMF) can both play a role in antibiotic toxicity. The susceptibility of Gram-negative bacteria to aminoglycoside antibiotics, particularly gentamicin, has previously been linked to both the production of ROS and the rate of antibiotic uptake that is mediated by the PMF, although the relative contributions of ROS and PMF to aminoglycoside toxicity has remained poorly understood. Herein, gentamicin was shown to elicit a very modest increase in ROS levels in an aerobically grown Escherichia coli clinical isolate. The well-characterised uncoupler 2,4-dinitrophenol (DNP) was used to disrupt the PMF, which resulted in a significant decrease in gentamicin lethality towards E. coli. DNP did not significantly alter respiratory oxygen consumption, supporting the hypothesis that this uncoupler does not increase ROS production via elevated respiratory oxidase activity. These observations support the hypothesis that maintenance of PMF rather than induction of ROS production underpins the mechanism for how the respiratory chain potentiates the toxicity of aminoglycosides. This was further supported by the demonstration that the uncoupler DNP elicits a dramatic decrease in gentamicin lethality under anaerobic conditions. Together, these data strongly suggest that maintenance of the PMF is the dominant mechanism for the respiratory chain in potentiating the toxic effects of aminoglycosides.

Polycation Architecture Affects Complexation and Delivery of Short Antisense Oligonucleotides: Micelleplexes Outperform Polyplexes.

Herein, we examine the complexation and biological delivery of a short single-stranded antisense oligonucleotide (ASO) payload with four polymer derivatives that form two architectural variants (polyplexes and micelleplexes): a homopolymer poly(2-dimethylaminoethyl methacrylate) (D), a diblock polymer poly(ethylene glycol)methylether methacrylate-block-poly(2-dimethylaminoethyl methacrylate) (ObD), and two micelle-forming variants, poly(2-dimethylaminoethyl methacrylate)-block-poly(n-butyl methacrylate) (DB) and poly(ethylene glycol)methylether methacrylate-block-poly(2-dimethylaminoethyl methacrylate)-block-poly(n-butyl methacrylate) (ObDB). Both polyplexes and micelleplexes complexed ASOs, and the incorporation of an Ob brush enhances colloidal stability. Micellplexes are templated by the size and shape of the unloaded micelle and that micelle-ASO complexation is not sensitive to formulation/mixing order, allowing ease, versatility, and reproducibility in packaging short oligonucleotides. The DB micelleplexes promoted the largest gene silencing, internalization, and tolerable toxicity while the ObDB micelleplexes displayed enhanced colloidal stability and highly efficient payload trafficking despite having lower cellular uptake. Overall, this work demonstrates that cationic micelles are superior delivery vehicles for ASOs denoting the importance of vehicle architecture in biological performance.

Life-history attributes of juvenile Anopheles gambiae s.s. in central Uganda; implications for malaria control interventions.

Malaria is among the leading causes of death in Uganda, and Anopheles gambiae sensu stricto (s.s.) is the predominant vector. Although current vector control interventions have greatly reduced the malaria burden, the disease persists. New interventions are needed in order to eradicate them. Evaluation of new tools will require the availability of well-characterized test vector populations. Juvenile An. gambiae s.s. from Kibbuye and Kayonjo-derived populations were characterized under semi-field and laboratory conditions, given that various vector traits, including abundance and fitness are dependent on development profiles at this life stage. Ten replicates comprising 30 first instar larvae each were profiled for various life-history attributes (egg hatching, larval development time, larval survivorship, pupal weight and pupation rate). All parameters were similar for the two sites under laboratory conditions. However, the similarities or differences between field and laboratory development were parameter-specific. Whereas, larval survivorship and pupal weight were similar across seasons and laboratory in colonies from both sites, in the semi-field settings, pupation rate and larval survivorship differed between seasons in both sites. In addition, the average larval development time during the wet season was longer than that of the laboratory for both sites. Availability of mirror field sites is important for future tool evaluations.

Diagnostic accuracy of ultrasound to confirm endotracheal tube depth.

INTRODUCTION: Endotracheal intubation is commonly performed in the Emergency Department. Traditional measures for estimating and confirming the endotracheal tube (ETT) depth may be inaccurate or lead to delayed recognition. Ultrasound may offer a rapid tool to confirm ETT depth at the bedside. METHODS: This was a randomized trial assessing the diagnostic accuracy of ultrasound to confirm ETT depth. Three cadavers were intubated in a random sequence with the ETT placed high (directly below the vocal cords), middle (2 cm above the carina), or deep (ETT at the carina). Seven blinded sonographers assessed the depth of the ETT using ultrasound. Outcomes included diagnostic accuracy of sonographer identification, time to identification, and operator confidence based upon ETT location. A subgroup analysis was performed to assess diagnostic accuracy by operator confidence. RESULTS: 441 total assessments were performed (154 high, 154 middle, and 133 deep ETT placements). Overall accuracy was 84.8% (95% CI 81.1% to 88.0%). When placed high, ultrasound was 82.5% sensitive (95% CI 75.5% to 88.1%) and 92.3% specific (95% CI 88.6% to 95.1%) with a mean time to identification of 15.3 s (95% CI 13.6-17.0) and a mean operator confidence of 3.9/5.0 (95% CI 3.7-4.1). When the ETT was placed in the middle, ultrasound was 83.8% sensitive (95% CI 77.0% to 89.2%) and 92.3% specific (95% CI 88.6% to 95.1%) with a mean time to identification of 16.7 s (95% CI 14.6-18.8) and a mean operator confidence of 3.7/5.0 (95% CI 3.5-3.9). When the ETT was placed deep, ultrasound was 88.0% sensitive (95% CI 81.2% to 93.0%) and 92.2% specific (95% CI 88.6% to 94.6%) with a mean time to identification of 19.0 s (95% CI 17.3-20.7) and a mean operator confidence of 3.4/5.0 (95% CI 3.2-3.6). Sonographers were significantly more accurate when they reported a higher confidence score. CONCLUSION: Ultrasound was moderately accurate for identifying the ETT location in a cadaveric model and was more accurate when sonographers felt confident with their visualization. Future research should determine the accuracy of combining transtracheal ultrasound with lung sliding and other modifications to improve the accuracy.

Characteristics of Medical Malpractice Claims Involving Temporomandibular Joint Surgery in the United States.

PURPOSE: Medical malpractice claims contribute to the practice of defensive medicine which exposes patients to unnecessary tests and limits access to care. The purpose of this study is to characterize medical malpractice claims involving temporomandibular joint (TMJ) operations by oral and maxillofacial surgeons in the United States. MATERIALS AND METHODS: Retrospective cross-sectional study of closed medical malpractice claims against oral and maxillofacial surgeons in the Unites States insured by OMS National Insurance Company, RRG (OMSNIC), from January 1, 2016, through December 31, 2020. All claims were obtained from the OMSNIC claims database and classified by procedure type. The primary outcome measure was closed claims involving a TMJ operation. Claims regarding postoperative TMJ complications from non-TMJ operations were excluded. Predictor variables included alleged error and type of TMJ procedure performed. Claim outcome was reported as a secondary outcome measure. Additional outcomes measured included claims involving dentoalveolar or dental implant procedures. Descriptive statistics were performed, and risk ratios were calculated for TMJ claim settlement by alleged error and procedure. Significance was set at P < .05. RESULTS: A total of 1455 closed claims occurred during the study period. There were 14 closed claims involving a TMJ operation (0.96% of all claims). "Improper performance" was the most common alleged error for TMJ claims. Two claims (1 TMJ arthroscopy and 1 TMJ replacement) were settled with payment, and the alleged error for these claims was improper performance. No TMJ claim received a court-adjudicated payout. Dentoalveolar and dental implant-related claims made up 68.73% (n = 1,000) and 15.53% (n = 226) of all OMSNIC claims, respectively. The risk of a settlement was not significantly influenced by alleged error or TMJ procedure performed. CONCLUSIONS: Medical malpractice claims against oral and maxillofacial surgeons for TMJ operations are very uncommon. Medical malpractice risk should not factor into a surgeon's decision to exclude TMJ operations from their practice.

Alloys Used in Different Temporomandibular Joint Reconstruction Replacement Prostheses Exhibit Variable Microstructures and Electrochemical Properties.

PURPOSE: Metallic temporomandibular joint replacement (TMJR) systems vary depending on design, material composition, and manufacturing methods such as casting, forging, and additive manufacturing. Therefore, the purpose of this study was to measure the association between manufacturing process of TMJR systems in terms of microstructure and electrochemical properties. MATERIALS AND METHODS: The sample was composed of new or surgically retrieved TMJ replacement devices of either titanium alloy (Ti6Al4V) or cobalt-chromium-molybdenum (CoCrMo) alloy from 8 different manufacturers. The primary predictor variable was alloy type, according to its manufacturing process (wrought, cast, additively manufactured [AM]). The primary outcome variables were 1) microstructure (grain size, aspect ratio, and phase content) and 2) corrosion potential and current, polarization resistance, and capacitance. Differences between alloy groups were determined by t tests, Kruskal-Wallis, and Mann-Whitney tests. RESULTS: We demonstrated that the TMJR CoCrMo and Ti6Al4V alloy microstructures can vary broadly within American Society for Testing and Materials specifications, where the components made of Ti6Al4V had 3 types of microstructures (equiaxial, bimodal, and martensitic) out of 10 samples, and the components made of CoCrMo had 2 types of microstructure (equiaxial and dendritic) out of 16 samples. Some CoCrMo alloys exhibited preferential corrosion sites, while wrought Ti6Al4V alloys trended toward a superior corrosion behavior (corrosion rate: 2 × 10-9 A/cm2, polarization resistance: 5,000,000 kΩcm2, and capacitance: 10 µSsa/cm2) compared with AM alloys (39 × 10-9 A/cm2, 1676 kΩcm2, 36 µSsa/cm2, respectively), where 4 samples of each group were tested and repeated 5 times. Among four AM devices, two exhibited a significantly inferior corrosion behavior. CONCLUSIONS: Although AM is an exciting emerging new technology that allows manufacturing of custom-made TMJR, their corrosion behavior is still inferior in comparison to that of traditional wrought alloys. Preventing corrosion is crucial because it can cause surface defects that may lead to implant fracture.

Is Heterotopic Ossification Removal From Alloplastic Temporomandibular Joint Prosthesis Using Er,Cr:YSGG Laser Superior to Conventional Methods?

PURPOSE: Heterotopic ossification (HO) formed over the major components and fixation screw heads of an alloplastic temporomandibular joint replacement (TMJR) prosthesis can result in decreased quality of life, limited function, prosthesis failure, and hinder prosthesis revision, replacement, or removal. This study simulated HO removal from the major components and fixation screw heads of alloplastic TMJR prostheses using an erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser and compared the results to conventional methods of HO removal. The surface morphology and chemical structure of the exposed components were analyzed. The investigators hypothesize that HO removal with an Er,Cr:YSGG laser causes less damage to TMJR prosthesis components compared to conventional HO removal methods. METHODS: This multiple test descriptive analysis simulated HO removal from TMJR prostheses mounted to stereolithic models. Simulated HO removal was completed using a novel Er,Cr:YSGG laser method and conventional methods which utilized a fissure carbide bur in a high-speed rotary instrument, a standard osteotome, and an ultrasonic aspirator. Surfaces exposed on the TMJR prostheses were analyzed for morphological or chemical change using scanning electron microscopy, energy dispersive X-ray spectroscopy, and Raman spectroscopy. RESULTS: The Er,Cr:YSGG laser did not adversely affect the titanium screws or titanium components of the TMJR prostheses, while conventional methods of HO removal did. HO removal using the Er,Cr:YSGG laser and conventional methods both inflicted surface damage to the fossa ultrahigh molecular weight polyethylene component of the TMJR prostheses. CONCLUSION: Damage inflicted to titanium alloy or commercially pure titanium components of TMJR prostheses by conventional HO removal methods can be avoided by instead removing HO with an Er,Cr:YSGG laser. However, long exposure of the Er,Cr:YSGG laser to ultrahigh molecular weight polyethylene surfaces should be avoided. Additional research to expand on applications to other procedures and in other surgical fields is encouraged.