In vitro comparative study between complete arch conventional implant impressions and digital implant scans with scannable pick-up impression copings.

STATEMENT OF PROBLEM: Intraoral digital scan techniques have been widely used and sufficient evidence supports this technique in partially edentulous patients. However, the evidence supporting the use of intraoral scanners (IOSs) for edentulous patients is limited. PURPOSE: The purpose of this in vitro study was to measure and compare the accuracy of complete arch conventional pick-up implant impressions with open and closed trays, complete arch digital implant scans with IOSs, and 3-dimensional (3D) printed casts from complete arch digital implant scans. MATERIAL AND METHODS: Six implants were placed in a mandibular model. Scannable pick-up impression copings were inserted in the implants, scanned with a reference scanner, and exported in standard tessellation language (STL) format (Group Control). Splinted open-tray pick-up impressions (Group OT, n=5) and closed-tray pick-up impressions (Group CT, n=5) were made, and stone casts were fabricated. Digital scans (Group DS, n=5) were made with an IOS, and the STL files were exported to fabricate 3D printed casts (Group STL, n=5). Scannable pick-up impression copings were inserted in the dental implant analogs in Groups OT, CT, and STL and scanned with the reference scanner. Using a 3D inspection software program, the recording techniques were compared with the control. Root mean square (RMS) values were calculated from the control, and superimposed digitized casts from different recording techniques. Analysis of variance was used to determine differences in RMS values, and theTukey post hoc test was used to determine difference between different groups. RESULTS: Group CT had the lowest mean dimensional difference when superimposed with Group Control, followed by Groups DS, OT, and STL. Significant differences were found in RMS values between Control and digitized casts fabricated with different techniques (P<.05). The post hoc Tukey test revealed that Group DS (P<.05) was significantly different from the other groups, while no significant difference was found among Groups CT, OT, and STL (P>.05). CONCLUSIONS: Based on the findings of the present study, 3D printed casts from digital scans have the same accuracy as stone casts from conventional impressions in complete arch implant cases. Intraoral scans had the highest accuracy. Complete arch pick-up impression techniques using dual-functioning scannable pick-up impression copings are as accurate as splinted complete arch pick-up impressions.

Fabrication of a Dual-Purpose Implant Surgical Guide.

While surgical guides have allowed for more highly accurate immediate implant placement in the esthetic zone, only a few techniques have been described to predictably position an immediate implant provisional. Even fewer techniques have addressed repositioning a patient's extracted tooth for use as the interim implant restoration. This article describes a workflow for the fabrication of a dual-purpose surgical guide that allows for guidance of implant placement as well as repositioning of a decoronated tooth that will serve as a provisional. While other provisional techniques aim to recreate proper gingival contour, the benefit of repositioning of the original tooth is the preservation of the existing gingival margin position and existing critical contour of the emergence profile.

A randomized, double-blind pilot study of analgesic and anti-inflammatory effects of naproxen sodium and acetaminophen following dental implant placement surgery.

Introduction: Post-surgical pain following dental implant placement surgery is typically managed with non-opioid analgesics, including non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen. However, the comparative analgesic efficacy of over-the-counter doses of non-steroidal anti-inflammatory drugs and acetaminophen in implant patients is unknown. Therefore, we compared the analgesic and anti-inflammatory effects of naproxen sodium and acetaminophen after surgical placement of one or two dental implants. Methods: Adult patients were treated with naproxen sodium (440 mg loading dose +220 mg q8h, n = 15) or acetaminophen (1,000 mg q6h-max daily dose 3,000 mg, n = 15) for 3 days after implant placement in a randomized, double-blind design. Pain was assessed on a 0-10 scale every 20 min for 6 h after study medication treatment. Tramadol (50 mg) was available as a rescue medication. Plasma and gingival crevicular fluid (GCF) were collected prior to the surgery and 0, 1, 2, 4, 6, 24, and 72 h after surgery for quantification of interleukin (IL)-6, IL-8, and IL-1ß levels. Results: Pain scores were significantly lower in patients treated with naproxen sodium compared to those treated with acetaminophen. Inflammatory mediator levels in plasma and gingival crevicular fluid increased after surgery and returned to near baseline levels by 72 h. Plasma IL-6 levels were significantly lower 6 h after surgery in patients treated with naproxen sodium compared to acetaminophen. No differences in inflammatory mediator concentrations in gingival crevicular fluid were observed between the treatment groups. The number of implants placed and body mass index (BMI) influenced inflammatory mediator concentrations in plasma and gingival crevicular fluid, respectively. Discussion: Naproxen sodium was more effective than acetaminophen in reducing post-operative pain and systemic inflammation following surgical placement of one or two dental implants. Further studies are needed to determine whether these findings are applicable to more complex implant cases and how they affect clinical outcomes following implant placement. Clinical Trial Registration: ClinicalTrials.gov, identifier NCT04694300.

Experimental studies of the transmission of light through low-coverage regular or random arrays of silica micropillars supported by a glass substrate.

The transmission of light through low-coverage regular and random arrays of glass-supported silica micropillars of diameters 10-40 µm and height 10 µm is studied experimentally. Angle-resolved measurements of the transmitted intensity are performed at visible wavelengths by either a goniospectrophotometer or a multimodal imaging (Mueller) polarimetric microscope. It is demonstrated that for the regular arrays, the angle-resolved measurements are capable of resolving many of the densely packed diffraction orders that are expected for periodic structures of lattice constants 20-80 µm, but they also display features ("halos" and fringes) that are due to the scattering and guiding of light in individual micropillars or in the supporting glass slides. These latter features are also found in angle-resolved measurements on random arrays of micropillars of the same surface coverage. Finally, we perform a comparison of direct measurements of haze in transmission for our patterned glass samples with what can be calculated from the angle-resolved transmitted intensity measurements. Good agreement between the two types of results is found, which testifies to the accuracy of the angle-resolved measurements that we report.

Digital histology with Mueller microscopy: how to mitigate an impact of tissue cut thickness fluctuations.

Mueller microscopy studies of fixed unstained histological cuts of human skin models were combined with an analysis of experimental data within the framework of differential Mueller matrix (MM) formalism. A custom-built Mueller polarimetric microscope was used in transmission configuration for the optical measurements of skin tissue model adjacent cuts of various nominal thicknesses (5 to 30 µm). The maps of both depolarization and polarization parameters were calculated from the corresponding microscopic MM images by applying a logarithmic Mueller matrix decomposition (LMMD) pixelwise. The parameters derived from LMMD of measured tissue cuts and the intensity of transmitted light were used for an automated segmentation of microscopy images to delineate dermal and epidermal layers. The quadratic dependence of depolarization parameters and linear dependence of polarization parameters on thickness, as predicted by the theory, was confirmed in our measurements. These findings pave the way toward digital histology with polarized light by presenting the combination of optimal optical markers, which allows mitigating the impact of tissue cut thickness fluctuations and increases the contrast of polarimetric images for tissue diagnostics.

Investigation of dental cone-beam CT pixel data and a modified method for conversion to Hounsfield unit (HU).

OBJECTIVES: To investigate the relationship in dental cone-beam CT (CBCT) between the manufacturer-reported image pixel data and a modified conversion to CT number densities in Hounsfield unit (HU). METHODS: A standardized CT phantom was imaged using typical clinical parameters on CBCT from three manufacturers (Carestream 9300®, Carestream Health, Rochester, NY; J Morita 3D Accutomo®, J. Morita Mfg. Corp., Kyoto, Japan; and Planmeca Promax 3D®, Planmeca Helsinki, OY, Finland). Reconstructed axial slices were evaluated using regions of interest to ascertain the mean pixel value in five materials in the phantom. The Digital Imaging and Communications in Medicine data were also evaluated to determine if raw pixel data had been adjusted during the image reconstruction. A modified version of the existing manual HU conversion technique was applied, and the resultant slope and y-intercept were used to scale the pixel values ultimately to HU for all images. RESULTS: The DICOM header data show that a modified rescale y-intercept was applied to both the Carestream and Planmeca image data yielding manufacturer-produced results in HU. The Morita pixel data were unmodified and report in shades of grey or grey values (GV). The Carestream manufacturer-derived HU measurements showed good correlation in air (-1000 HU), but all other materials ranged from 2.6 to 13.5 σ from the specified phantom value. Results in the modified conversion technique images fell within 1.0-2.4 σ from the specified phantom values. CONCLUSIONS: While more studies are needed to test for regularity, this study suggests that our modified technique could be a means of getting more accurate quantitative data from dental CBCTs.

Apolipoprotein C-I is an APOE genotype-dependent suppressor of glial activation.

BACKGROUND: Inheritance of the human ε4 allele of the apolipoprotein (apo) E gene (APOE) significantly increases the risk of developing Alzheimer's disease (AD), in addition to adversely influencing clinical outcomes of other neurologic diseases. While apoE isoforms differentially interact with amyloid ß (Aß), a pleiotropic neurotoxin key to AD etiology, more recent work has focused on immune regulation in AD pathogenesis and on the mechanisms of innate immunomodulatory effects associated with inheritance of different APOE alleles. APOE genotype modulates expression of proximal genes including APOC1, which encodes a small apolipoprotein that is associated with Aß plaques. Here we tested the hypothesis that APOE-genotype dependent innate immunomodulation may be mediated in part by apoC-I. METHODS: ApoC-I concentration in cerebrospinal fluid from control subjects of differing APOE genotypes was quantified by ELISA. Real-time PCR and ELISA were used to analyze apoC-I mRNA and protein expression, respectively, in liver, serum, cerebral cortex, and cultured primary astrocytes derived from mice with targeted replacement of murine APOE for human APOE ε3 or ε4. ApoC-I direct modulation of innate immune activity was investigated in cultured murine primary microglia and astrocytes, as well as human differentiated macrophages, using specific toll-like receptor agonists LPS and PIC as well as Aß. RESULTS: ApoC-I levels varied with APOE genotype in humans and in APOE targeted replacement mice, with ε4 carriers showing significantly less apoC-I in both species. ApoC-I potently reduced pro-inflammatory cytokine secretion from primary murine microglia and astrocytes, and human macrophages, stimulated with LPS, PIC, or Aß. CONCLUSIONS: ApoC-I is immunosuppressive. Our results illuminate a novel potential mechanism for APOE genotype risk for AD; one in which patients with an ε4 allele have decreased expression of apoC-I resulting in increased innate immune activity.

Effect of hepatitis C virus (HCV) genotype on HCV and HIV-1 disease.

The relationship between hepatitis C virus (HCV) genotype and HCV and human immunodeficiency virus (HIV) type 1 disease is not well defined. The present study analyzed data from a cohort of 207 HIV-1-infected and 126 HIV-1-uninfected children and adolescents with hemophilia who enrolled in the Hemophilia Growth and Development Study and were followed for 7 years. The mean HCV RNA level was higher in the participants in the HCV genotype 1 group than in the participants the HCV non-genotype 1 group, among both the HIV-1-infected (difference, +0.33 log(10) copies/mL; P=.038) and HIV-1-uninfected (difference, +0.59 log(10) copies/mL; P=.008) participants. Although HCV genotype was not associated with differences in HIV-1 RNA level, a significantly lower mean CD4(+) T cell count (difference, -127 cells/ microL; P=.026) and percentage of CD4(+) T cells (difference, -4.3%; P=.027) were observed in the participants in the HCV genotype 1 group, compared with those in the participants in the HCV non-genotype 1 group. In addition, the participants in the HCV genotype 1 group were at increased risk for progression to AIDS-related mortality (hazard ratio, 2.44; P=.037). The present study suggests that HCV infection and genotype may influence the natural history of HCV and HIV-1 disease.

Concurrent cerebral american trypanosomiasis and toxoplasmosis in a patient with AIDS.

We report a case of concurrent cerebral infection with Trypanosoma cruzi and Toxoplasma gondii in a patient with acquired immunodeficiency syndrome (AIDS). A 22-year-old El Salvadoran man initially improved during receipt of antitoxoplasmosis therapy, but he had rapidly progressive hemiplegia. Magnetic resonance imaging showed an abnormal finding in the left internal capsule, and cytological analysis of cerebrospinal fluid revealed T. cruzi trypomastigotes. Despite prompt therapy with nifurtimox, the patient's mental status declined, and he died of nosocomial complications. Although infrequent, T. cruzi infection should be considered in the differential diagnosis of brain lesions in patients with AIDS from regions of endemicity.

Reversal of linezolid-associated cytopenias, but not peripheral neuropathy, by administration of vitamin B6.

OBJECTIVES: We sought to determine if vitamin B6 therapy would reverse linezolid-associated cytopenias and/or peripheral neuropathy. PATIENTS AND METHODS: We have recently treated two patients with disseminated Mycobacterium abscessus infections with prolonged (> or =9 month) courses of linezolid. Both patients developed cytopenias related to linezolid, and one patient also developed peripheral neuropathy. Because continuing linezolid therapy was required, we administered vitamin B6 (50 mg orally once a day) in an attempt to mitigate the associated cytopenias. RESULTS: The cytopenias in both patients reversed following administration of vitamin B6, and stabilized during prolonged linezolid therapy, although the peripheral neuropathy did not. CONCLUSIONS: Vitamin B6 treatment may be useful to prevent or modify the course of linezolid-associated cytopenias. More formal and rigorous study of vitamin B6 therapy in patients receiving prolonged courses of linezolid is warranted.