Influence of implant scanbody material,position and operator on the accuracy of digital impression for complete-arch: A randomized in vitro trial

PurposeTo evaluate the influence of implant scanbody (ISB) material, position and operator on the accuracy of a confocal microscopy intraoral scanning (IOS) for complete-arch implant impression.MethodsAn edentulous maxillary model with 6 internal hexagonal connection analogues was scanned with an extraoral optical scanner to achieve a reference file. Three ISBs made of different materials (polyetheretherketone (Pk), titanium (T) and Pk with a titanium base (Pkt)) were scanned with IOS by 3 operators. The resulting 45 test files were aligned to the reference file with a best fit algorithm. Linear (ΔX, ΔY and ΔZ-axis) and angular deviations (ΔANGLE) were assessed. Absolute values of the linear discrepancies were summed up to obtain a global measure of linear absolute error (ΔASS). Influence of ISB material, position and operator was statistically assessed using the mixed general linear model.ResultsAt multivariate analysis, whenΔASS was considered as response variable, it was identified a significant influence of material (p < 0.0001) and position (p = 0.0009) while no significant operator effect was detected.When ΔANGLE was considered as response variable, material and position significantly influenced the expected ΔANGLE (p = 0.0232 and p < 0.0001) and no operator effect was identified.ConclusionsThe investigated IOS for complete-arch digital impression was influenced by the ISB material with peek reporting the best results on both linear and angular measurements followed by titanium, peek-titanium resulting as the less accurate. Implant angulation affected significantly the linear deviations while implant position the angular deviations. Operator did not show any significant effect on the IOS accuracy.     

Grieving in the digital era: Mapping online support for grief and bereavement

ObjectiveTo describe the landscape of digital resources available for grief and bereavement, and to explore cultural variations through the analysis of patterns in three languages with a multinational repartition (English, French and Spanish).MethodsFor each language, websites were collected through a systematized approach and classified according to their category (governmental, health, educational, social media, conventional media, spiritual), their country of origin, and the type of support they offered (practical support, services, peer support, informational support, resources).ResultsA total of 2587 websites (English: 1003; French 678; Spanish: 906) were analyzed. Cultural variations were observed both for the websites’ categories and the types of support. Half of the websites presented at least one type of support, informational support being the most prevalent, followed by practical support. English websites presented significantly more support than Spanish websites, with French websites in between.Practice implicationsBy using an extensive survey, our results allow for a general mapping of online websites that is comparable across languages, but also unveil digital dynamics unknown to date. These results further the multicultural understanding of digital support for grief and bereavement, propose an innovative and operational typology for online support and raise awareness of the current support landscape.     

Cervical fracture patterns associated with blunt cerebrovascular injures when utilizing computed tomographic angiography: a systematic review and meta-analysis

BACKGROUND CONTEXTPrior studies have demonstrated an association between cervical spine fractures and blunt cerebrovascular injuries (BCVI) due to the intimate anatomic relationship between the cervical spine and the vertebral arteries. Digital subtraction angiography (DSA) has historically been the gold standard, but computed tomography angiography (CTA) is commonly used to screen for BCVI in the trauma setting. However, there is no consensus regarding which fracture patterns mandate screening. Over aggressive screening may lead to increased radiation, increased false positives, and overtreatment of patients which can cause unnecessary patient harm, and increased healthcare costs.PURPOSEThe aim of this meta-analysis is to analyze which cervical spine fracture patterns are most predictive of BCVI when utilizing CTA.STUDY DESIGN/SETTINGSystematic review and meta-analysis.OUTCOME MEASURESOdds ratios for specific cervical fracture patterns and risk of developing a BCVI.METHODSA systematic literature review of all English language studies from 2000-2020 was conducted. The year 2000 was chosen as the cut-off because use of CTA prior to 2000 was rare. Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Scopus, Global Index Medicus, and ClinicalTrials.gov were queried. Studies were included if they met the following criteria: (1) the diagnostic imaging modality was CTA; (2) investigated blunt cervical trauma; (3) noted specific cervical spine fracture patterns associated with BCVI; (4) odds ratios for specific cervical spine fracture patterns or the odds ratio could be calculated; (5) subjects were 18 years old or older. Studies were excluded if they: (1) included DSA or magnetic resonance imaging; (2) included penetrating cervical trauma; (3) included pediatric patients less than 18 years of age; (4) were not written in English. All statistical analysis was performed using R Studio (RStudio, Boston, MA, USA).RESULTSThe initial search, after duplicates were removed, resulted in 10,940 articles for independent review. Six studies met the criteria for inclusion in the meta-analysis. Specific fracture patterns mentioned are isolated C1, C2, C3 fractures, any C1–C3 fracture, any C4–C7 fracture, two-level fractures, subluxation/dislocations, and transverse foramen (TF) fractures. Three studies were included in the meta-analysis for C1, C2, C1–C3, subluxations/dislocations, and TF fractures. Two studies were included in the meta-analysis for C3, C4–C7, and two-level fractures. The pooled odds ratio with 95% confidence interval for: C1 fractures and BCVI is 1.3 (0.8–2.1); C2: 1.6 (0.9–2.8); C3: 1.8 (0.9–3.6); C1–C3: 2.2 (1.1–4.2); C4–C7: 0.7 (0.3–1.7); Two-level: 2.5 (1.4–4.6); Subluxation/Dislocation: 2.9 (1.8–4.5); TF: 3.6 (1.4–8.9).DISCUSSION/CONCLUSIONThis study found that when utilizing CTA for screening of BCVI only fractures in the C1-C3 region, two-level fractures, subluxations/dislocations, and transverse foramen fractures were associated with increased incidence of a BCVI. Further refinement of protocols for CTA in the setting of blunt cervical trauma may help limit unnecessary patient harm from overtreatment and reduce healthcare costs.     

Using droplet digital PCR to screen for rare blood donors: Proof of principle

BackgroundDigital droplet PCR (ddPCR) is a very sensitive high throughput genotyping methodology. To date, the use of ddPCR in immunohematology is restricted to fetal genotyping of red blood cell antigens. Our hypothesis is that this technology could be applied to screen for rare red blood cell genotypes, such as Di(b-).MethodsNucleic acid of 3168 donors was extracted for viral screening routine in pools of 6, which were converted into three types of 48-donor pools: control pools (only DI*B/*B samples), pools with varying amount of DI*A/*B samples (n = 1–5) and a pool with one rare DI*A/*A sample. Pools were genotyped using ddPCR to detect and quantify DI*A and DI*B alleles.ResultsDI*A allele was accurately detected in all pools containing Di(a + b+) samples and in the pool containing one Di(a + b-) sample. No copies were detected in the control pools (n = 60). The ratio between the number of DI*A and DI*B copies varied significantly between the pools and the triplicates.ConclusionThe proposed ddPCR assay was accurate in identifying the rare DI*A allele in large pools of donors and can be applied to screen for Di(b-) phenotype. The strategy can potentially be extended to search for other rare RBC phenotypes.     

Brief digital sleep questionnaire powered by machine learning prediction models identifies common sleep disorders

IntroductionWe developed and validated an abbreviated Digital Sleep Questionnaire (DSQ) to identify common societal sleep disturbances including insomnia, delayed sleep phase syndrome (DSPS), insufficient sleep syndrome (ISS), and risk for obstructive sleep apnea (OSA).MethodsThe DSQ was administered to 3799 community volunteers, of which 2113 were eligible and consented to the study. Of those, 247 were interviewed by expert sleep physicians, who diagnosed ≤2 sleep disorders. Machine Learning (ML) trained and validated separate models for each diagnosis. Regularized linear models generated 15–200 features to optimize diagnostic prediction. Models were trained with five-fold cross-validation (repeated five times), followed by robust validation testing. ElasticNet models were used to classify true positives and negatives; bootstrapping optimized probability thresholds to generate sensitivities, specificities, accuracies, and area under the receiver operating curve (AUC).ResultsCompared to reference subgroups, physician-diagnosed sleep disorders were marked by DSQ evidence of sleeplessness (insomnia, DSPS, OSA), sleep debt (DSPS, ISS), airway obstruction during sleep (OSA), blunted circadian variability in alertness (DSPS), sleepiness (DSPS and ISS), increased alertness (insomnia) and global impairment in sleep-related quality of life (all sleep disorders). ElasticNet models validated each diagnosis with high sensitivity (80–83%), acceptable specificity (63–69%), high AUC (0.80–0.85) and good accuracy (agreement with physician diagnoses, 68–73%).DiscussionA brief DSQ readily engaged and efficiently screened a large population for common sleep disorders. Powered by ML, the DSQ can accurately classify sleep disturbances, demonstrating the potential for improving the sleep, health, productivity and safety of populations.     

Titanium dioxide-based scanning powder can modulate cell activity of oral soft tissue - Insights from in vitro studies with L929 cells and periodontal fibroblasts

PurposeTo reveal the impact of titanium dioxide-based scanning powder for intraoral digital impression on the biological activity of oral fibroblasts.MethodsMurine L929 cells and human periodontal ligament (PDLF) and gingival fibroblasts (GF) were treated with ten-fold serial dilutions of scanning powder and the corresponding conditioned medium (filtrate of overnight incubation of powder in medium) starting with 30 mg/ml. Bicinchoninic acid protein assay, formazan- and resazurin-based toxicity assays, live/dead and annexin V/propidium iodide (PI) staining and immunoassays for interleukin (IL)-6 and IL-8 were performed. Powder composition was analyzed using energy dispersive X-ray spectroscopy (EDS).ResultsFormazan and resazurin conversion was lesser in L929 cells than PDLF and GF in the presence of scanning powder. Induction of cell death was caused by 30 mg/ml of powder in L929 cells but not in PDLF and GF. No pronounced impact of the conditioned medium was seen in cytotoxicity assays or live/dead-, and annexin V/PI staining. In PDLF and GF IL-6 expression was increased by the powder, while there was a decrease in IL-8. Powder particles did not deplete protein from medium. EDS showed a heterogeneous mixture consisting predominantly of titanium dioxide.ConclusionsScanning powder decreased cell activity and induced cell death in L929 cells at high concentrations. Human oral fibroblasts showed an increase in IL-6 levels but more resistance to the cytotoxicity of the powder. Within the limitations of an in vitro study our results suggest that proper cleaning after scanning is of clinical relevance to avoid potential unwanted effects of the powder.