An experimental approach to analyze aerosol and splatter formations due to a dental procedure.

Throughout 2020 and beyond, the entire world has observed a continuous increase in the infectious spread of the novel coronavirus (SARS-CoV-2) otherwise known as COVID-19. The high transmission of this airborne virus has raised countless concerns regarding safety measures employed in the working conditions for medical professionals. Specifically, those who perform treatment procedures on patients which intrinsically create mists of fine airborne droplets, i.e., perfect vectors for this and other viruses to spread. The present study focuses on understanding the splatter produced due to a common dentistry technique to remove plaque buildup on teeth. This technique uses a high-speed dentistry instrument, e.g., a Cavitron ultrasonic scaler, to scrape along the surface of a patient's teeth. This detailed understanding of the velocity and the trajectory of the droplets generated by the splatter will aid in the development of hygiene mechanisms to guarantee the safety of those performing these procedures and people in clinics or hospitals. Optical flow tracking velocimetry (OFTV) method was employed to obtain droplet velocity and trajectory in a two-dimensional plane. Multiple data collection planes were taken in different orientations around a model of adult mandibular teeth. This technique provided pseudo-three-dimensional velocity information for the droplets within the splatter developed from this high-speed dental instrument. These results indicated that within the three-dimensional splatter produced there were high velocities (1-2 m/s) observed directly below the intersection point between the front teeth and the scaler. The splatter formed a cone-shape structure that propagated 10-15 mm away from the location of the scaler tip. From the droplet trajectories, it was observed that high velocity isolated droplets propagate away from the bulk of the splatter. It is these droplets which are concerning for health safety to those performing the medical procedures. Using a shadowgraphy technique, we further characterize the individual droplets' size and their individual velocity. We then compare these results to previously published distributions. The obtained data can be used as a first step to further examine flow and transport of droplets in clinics/dental offices.

Correlated charge noise and relaxation errors in superconducting qubits.

The central challenge in building a quantum computer is error correction. Unlike classical bits, which are susceptible to only one type of error, quantum bits (qubits) are susceptible to two types of error, corresponding to flips of the qubit state about the X and Z directions. Although the Heisenberg uncertainty principle precludes simultaneous monitoring of X- and Z-flips on a single qubit, it is possible to encode quantum information in large arrays of entangled qubits that enable accurate monitoring of all errors in the system, provided that the error rate is low1. Another crucial requirement is that errors cannot be correlated. Here we characterize a superconducting multiqubit circuit and find that charge noise in the chip is highly correlated on a length scale over 600 micrometres; moreover, discrete charge jumps are accompanied by a strong transient reduction of qubit energy relaxation time across the millimetre-scale chip. The resulting correlated errors are explained in terms of the charging event and phonon-mediated quasiparticle generation associated with absorption of γ-rays and cosmic-ray muons in the qubit substrate. Robust quantum error correction will require the development of mitigation strategies to protect multiqubit arrays from correlated errors due to particle impacts.

Impact of hydraulic retention time on phosphorus removal from wastewater using reactive media.

Phosphorus (P) discharge from wastewater treatment plants into the environment contributes to eutrophication issues. Reactive media filters represent an effective, simple and cost-effective solution to decrease the P content. Previous research used various experimental designs and often synthetic wastewater, making assessment of real-world performance difficult. This study assesses the impact of the hydraulic retention time (HRT) on P removal using real wastewater to refine design criteria for full-scale installations. Four media were compared in column experiments for >200 days. Different HRTs were applied and initially the media achieved low P effluent concentrations of >0.1 mg/L PO4-P, increasing over time. Best P removal was observed for the highest HRT with on average >99%. HRT was seen to be the driving factor for P removal rather than media capacity. Three of the four materials showed pH levels above 12 initially, decreasing over time. Water quality parameters, including organics, solids and metals, were monitored. In-depth analysis confirmed formation of calcium phosphate precipitation on the media's surface. The results suggest the importance of an optimal HRT to achieve high P removal and show that the reactive media application is an appropriate technology for P removal on small sites if the elevated pH is addressed.

Phenotypic Spectrum of Pentosan Polysulfate Sodium-Associated Maculopathy: A Multicenter Study.

IMPORTANCE: A unique pigmentary maculopathy was recently described in 6 patients with long-term exposure to pentosan polysulfate sodium (PPS), a long-standing oral therapy for interstitial cystitis. OBJECTIVE: To characterize the exposure characteristics and clinical manifestations of PPS-associated maculopathy. DESIGN, SETTING, AND PARTICIPANTS: In this multi-institutional case series, medical records of patients who exhibited the characteristic maculopathy in the setting of prior PPS exposure were retrospectively reviewed. Data were collected from August 1, 2012, to October 1, 2018, and data were analyzed from October 2018 to January 2019. MAIN OUTCOMES AND MEASURES: Drug exposure, visual acuity, and retinal imaging characteristics. RESULTS: Of the 35 included patients (70 eyes), 34 (97%) were female, and the median (range) age was 60 (37-79) years. The median (range) duration of PPS intake was 15 (3-22) years, and the median (range) cumulative exposure was 1.61 (0.44-4.31) kg. The leading visual symptoms were metamorphopsia, blurred vision, and prolonged dark adaptation. Median (range) logMAR visual acuity of all eyes was 0.10 (-0.12 to 1.18). Fundus examination often revealed hyperpigmented macular spots (34 of 64 eyes [53%]) with interspersed pale-yellow deposits, although less commonly in eyes that exhibited retinal pigment epithelial atrophy (6 of 26 eyes [23%]; P < .001). Optical coherence tomography showed foci of retinal pigment epithelium elevation or thickening associated with hyperreflectance on near-infrared reflectance imaging. Fundus autofluorescence imaging typically revealed a symmetric, confluent pattern of hyperautofluorescent and hypoautofluorescent spots that involved the fovea in all eyes and extended to the retinal periphery in 24 eyes (36%). Longitudinal evaluation demonstrated dynamic changes in pigmentary abnormalities. CONCLUSIONS AND RELEVANCE: These findings suggest that PPS-associated maculopathy is a vision-threatening condition that can manifest in the setting of long-term exposure to the drug. Multimodal imaging posits a distinctive clinical phenotype, characterized in this cohort by dynamic alterations within the retinal pigment epithelium and at the retinal pigment epithelium-photoreceptor interface. Ongoing work might explore causality and direct screening guidelines.

Culture-Proven Endophthalmitis After Intravitreal Injection: A 10-Year Analysis.

BACKGROUND AND OBJECTIVE: To report on the microbiology, management, and visual outcomes of intravitreal injection (IVI)-associated, culture-proven endophthalmitis. PATIENTS AND METHODS: All patients seen at a tertiary referral center with culture-proven endophthalmitis associated with an IVI between June 2007 and July 2017 were included in this retrospective analysis. RESULTS: Thirty-five patients with culture-positive endophthalmitis following IVI were identified. All gram-positive organisms (34 of 35) were susceptible to vancomycin. Cases due to pathogens associated with oral or respiratory flora were common (31.4%, n = 11), presented earlier (2.0 days vs. 4.6 days, P < .001), were more likely to undergo pars plana vitrectomy (81.8% vs. 25.0%, P = .002) and had worse visual acuity outcomes. CONCLUSION: IVI-associated endophthalmitis pathogens and anti-microbial susceptibilities in the Pacific Northwest are similar to those reported from other geographic locations. Bacteria associated with the oral and respiratory flora are common isolates that result in a more aggressive course and worse visual outcomes. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:33-38.].

Manifestation of a solitary retinal astrocytic hamartoma in a patient with Best macular dystrophy.

PURPOSE: To report the case of an adolescent male with a history of Best macular dystrophy and retinal astrocytic hamartoma. OBSERVATIONS: A 15 year old male with a history of Best macular dystrophy who had been followed by ophthalmology for 9 years was noted to have progressive enlargement of a superonasal peripapillary retinal lesion. Imaging and exam are consistent with a diagnosis of retinal astrocytic hamartoma. There were no extraocular signs or symptoms that were diagnostic of a phakamatosis. Genetic testing was positive for a mutation in BEST1, but not TSC1 or TSC2. CONCLUSIONS AND IMPORTANCE: Retinal astrocytic hamartoma is an unusual association with Best macular dystrophy, and this case highlights the balanced approach needed to navigate a potentially complex work-up.

Visual Outcomes after Vitrectomy for Terson Syndrome Secondary to Traumatic Brain Injury.

PURPOSE: To evaluate visual outcomes after vitrectomy for intraocular hemorrhages secondary to traumatic brain injury. DESIGN: Retrospective, observational case series. PARTICIPANTS: A total of 28 eyes in 20 patients undergoing vitrectomy for Terson syndrome secondary to traumatic brain injury between 1997 and 2015. METHODS: We reviewed the records of patients undergoing a standard 20-gauge or 23-gauge pars plana vitrectomy for intraocular hemorrhages secondary to traumatic brain injury, and the timing of vitrectomy in relation to the inciting intracranial event was recorded. MAIN OUTCOME MEASURES: The primary outcome measure was the change in the preoperative visual acuity score at postoperative month 1 and at the last noted clinic appointment. RESULTS: A total of 28 eyes in 20 patients (all male) underwent pars plana vitrectomy for intraocular hemorrhages secondary to traumatic brain injury. The mean preoperative baseline logarithm of the minimum angle of resolution (logMAR) (Snellen) best-corrected visual acuity (BCVA) was 1.81±0.56 (20/1290). At 1-month postoperative follow-up, the mean BCVA was 0.30±0.33 (20/40). At the date of the last follow-up, the mean BCVA was 0.15±0.24 (20/30) and the median BCVA was 0.00 (20/20). Although the difference between preoperative and postoperative BVCA was significantly different at 1 month and the final postoperative clinic visits (P < 0.001), there was not a correlation between preoperative visual acuity as a predictor of final postoperative visual acuity outcome (r=-0.32; P = 0.09; 95% confidence interval [CI] -0.62 - 0.06). At the date of the last follow-up, the differences in visual outcomes between the individuals undergoing vitrectomy within 3 months of the inciting event, 0.08±0.15 (20/25), were not significantly different than those undergoing surgical intervention after 3 months, 0.18±0.27 (20/30) (P = 0.28). Three cases among those undergoing vitrectomy after 3 months were complicated by retinal detachment, none of which resulted in a BCVA worse than when the patient originally presented preoperatively. CONCLUSIONS: In this retrospective series of patients without other ocular pathology, surgical intervention effectively provided rapid visual recovery in the majority of individuals with intraocular hemorrhages secondary to traumatic brain injury, irrespective of the timing of vitrectomy or of preoperative visual acuity.

Physician-Industry Interactions and Anti-Vascular Endothelial Growth Factor Use Among US Ophthalmologists.

IMPORTANCE: The publication of the US Physician Payments Sunshine Act provides insight into the financial relationship between physicians and the pharmaceutical industry. This added transparency creates new opportunities of using objective data to better understand prior research that implicates pharmaceutical promotions as an important factor in a physician's decision-making process. OBJECTIVE: To assess the association between reported industry payments and physician-prescribing habits by comparing the use of anti-vascular endothelial growth factor (VEGF) intravitreal injections by US ophthalmologists to the industry payments these same physicians received. DESIGN, SETTING, PARTICIPANTS: This study reviews data from the Centers for Medicare & Medicaid Services (CMS) 2013 Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use File and the CMS-sponsored August through December 2013 Open Payments program (Physician Payments Sunshine Act). Ophthalmologists who prescribe anti-VEGF injections for all indications were analyzed. MAIN OUTCOMES AND MEASURES: Association between industry payments reportedly received and the number and type of anti-VEGF injections administered. RESULTS: A total of 3011 US ophthalmologists were reimbursed by CMS for 2.2 million anti-VEGF injections in 2013. Of these physicians, 38.0% reportedly received $1.3 million in industry payments for ranibizumab and aflibercept. Analysis revealed positive associations between increasing numbers of reported industry payments and total injection use (r = 0.24; 95% CI, 0.22-0.26; P < .001), aflibercept and ranibizumab injection use (r = 0.32; 95% CI, 0.29-0.34; P < .001), and percentage of injections per physician that were aflibercept or ranibizumab (r = 0.27; 95% CI, 0.25-0.29; P < .001). A smaller association was noted between greater number of industry payments and bevacizumab injection use (r = 0.07; 95% CI, 0.04-0.09; P < .001). Similar associations were found between the total dollars of reported industry payments received to injection use. Subgroup analysis further revealed that physicians receiving $1 to $25 in reported industry benefits were more likely than those not receiving industry payments to perform a greater percentage of their injections with aflibercept and ranibizumab. CONCLUSIONS AND RELEVANCE: Among ophthalmologists who prescribe anti-VEGF medications, there is a positive association between reported pharmaceutical payments and increased use of aflibercept and ranibizumab injections. As is inherent to the design of correlation studies, this analysis cannot determine whether the payments reported caused the increased use, are a result of the increased use, or are merely associated with some other factor that causes the increased use.

A case of recurrent bilateral uveitis independently associated with dabrafenib and pembrolizumab therapy.

PURPOSE: To report the case of an adult female who presented on different occasions with recurrent uveitis provoked by initiating therapy of two recently approved agents, dabrafenib and pembrolizumab, for treatment of metastatic melanoma. OBSERVATIONS: A 61 year old female presented with bilateral anterior uveitis after initiating therapy with dabrafenib for advanced metastatic melanoma. Her symptoms resolved and exam improved with oral and topical steroid therapy. Months later, she was started on pembrolizumab and transitioned off dabrafenib. Within days of starting pembrolizumab, she developed recurrent bilateral uveitis. This responded to escalating doses of topical and oral corticosteroid therapy and resolved following discontinuation of pembrolizumab. Nine months later, our patient received her third dose of pembrolizumab due to further progression of melanoma and within three days developed blurry vision, photophobia and subsequent ophthalmologic exam demonstrated bilateral panuveitis. CONCLUSIONS AND IMPORTANCE: Dabrafenib and pembrolizumab therapy have both previously been associated with uveitis. Here, we document a case of a woman who developed acute uveitis in response to beginning therapy with dabrafenib and then later developed acute uveitis soon after initiating pembrolizumab. To our knowledge, this is the first time this uncommon side-effect has been reported in the same patient after receiving sequential targeted agents and checkpoint inhibitors.

Modern Strategies to Save Sight in Diabetes.

Owing to the global epidemic of obesity, the incidence of diabetes and its complications are rapidly increasing around the world. Yet, visual impairment caused by diabetic retinopathy is paradoxically on the decline. This improvement is due to better understanding of etiologic mechanisms, increased screening, and advent of newer therapies. Here, we discuss salient developments in the comprehension of the root causes of diabetic retinopathy and the molecular mechanisms underlying current treatment approaches.

Energy benchmarking in wastewater treatment plants: the importance of site operation and layout.

Energy benchmarking is a powerful tool in the optimization of wastewater treatment plants (WWTPs) in helping to reduce costs and greenhouse gas emissions. Traditionally, energy benchmarking methods focused solely on reporting electricity consumption, however, recent developments in this area have led to the inclusion of other types of energy, including electrical, manual, chemical and mechanical consumptions that can be expressed in kWh/m3. In this study, two full-scale WWTPs were benchmarked, both incorporated preliminary, secondary (oxidation ditch) and tertiary treatment processes, Site 1 also had an additional primary treatment step. The results indicated that Site 1 required 2.32 kWh/m3 against 0.98 kWh/m3 for Site 2. Aeration presented the highest energy consumption for both sites with 2.08 kWh/m3 required for Site 1 and 0.91 kWh/m3 in Site 2. The mechanical energy represented the second biggest consumption for Site 1 (9%, 0.212 kWh/m3) and chemical input was significant in Site 2 (4.1%, 0.026 kWh/m3). The analysis of the results indicated that Site 2 could be optimized by constructing a primary settling tank that would reduce the biochemical oxygen demand, total suspended solids and NH4 loads to the oxidation ditch by 55%, 75% and 12%, respectively, and at the same time reduce the aeration requirements by 49%. This study demonstrated that the effectiveness of the energy benchmarking exercise in identifying the highest energy-consuming assets, nevertheless it points out the need to develop a holistic overview of the WWTP and the need to include parameters such as effluent quality, site operation and plant layout to allow adequate benchmarking.

Measurement of radiative proton capture on 18F and implications for oxygen-neon novae.

The rate of the 18F(p,γ)19Ne reaction affects the final abundance of the γ-ray observable radioisotope 18F, produced in novae. However, no successful measurement of this reaction exists and the rate used is calculated from incomplete information on the contributing resonances. Of the two resonances thought to play a significant role, one has a radiative width estimated from the assumed analogue state in the mirror nucleus, 19F. The second does not have an analogue state assignment at all, resulting in an arbitrary radiative width being assumed. Here, we report the first successful direct measurement of the 18F(p,γ)^19Ne reaction. The strength of the 665 keV resonance (Ex=7.076 MeV) is found to be over an order of magnitude weaker than currently assumed in nova models. Reaction rate calculations show that this resonance therefore plays no significant role in the destruction of ^{18}F at any astrophysical energy.

Clinical manifestations and treatment of idiopathic and Wegener granulomatosis-associated subglottic stenosis.

OBJECTIVE: To compare and contrast the manifestations and surgical management of subglottic stenosis in patients with airway obstruction attributed to granulomatosis with polyangiitis (GPA), previously known as Wegener granulomatosis, and those with idiopathic subglottic stenosis (iSGS). DESIGN: Retrospective medical chart review. Review of subglottic stenosis cases seen in the otolaryngology department of an academic medical center from 2005 through 2010. Data were obtained on disease presentation, operative management. and findings. SETTING: Tertiary referral center. PARTICIPANTS: A total of 24 patients with iSGS and 15 patients with GPA-associated subglottic stenosis (GPA-SGS). RESULTS: All individuals with iSGS were female, and 40% of patients with GPA-SGS were male (P < .01). Patients with iSGS tended to have a higher Myer-Cotton stenosis grade at the time of dilation than those with GPA-SGS (P = .02). Individuals with GPA-SGS were more likely to undergo tracheotomy as a result of disease-related complications than individuals with iSGS (P < .01). No patients with an open airway reconstruction in the iSGS group required follow-up mechanical dilation. In contrast, all patients with open airway reconstructions in the GPA-SGS group underwent more than 1 subsequent airway dilation (P < .01). CONCLUSIONS: While surgical utilization is the mainstay of treatment in iSGS and GPA-SGS, iSGS occurs almost exclusively in females and presents with a greater degree of stenosis at the time of endoscopic dilation. In contrast, GPA-SGS is associated with greater rates of tracheotomy. Open airway reconstruction may be used in the treatment of iSGS and GPA-SGS but is much more effective in iSGS.

Progression and management of Wegener's granulomatosis in the head and neck.

OBJECTIVES/HYPOTHESIS: To describe the otolaryngologic presentation and natural history of granulomatosis with polyangiitis (GPA), previously known as Wegener's granulomatosis, and to compare otolaryngologic outcomes of patients with systemic GPA to those with a limited form of GPA confined to the head and neck. STUDY DESIGN: Retrospective chart review. METHODS: Review of GPA cases (identified by serology, biopsy, or clinical presentation) seen in the otolaryngology department of an academic medical center. RESULTS: A total of 24 patients were identified; each patient was followed for an average 6.8 years. Sinusitis and subglottic stenosis were the most commonly observed head and neck manifestations at diagnosis, seen in 64% and 36%, respectively. Over time, disease spread to additional sites in more than half the cohort (n = 14), but only two of 13 patients with disease initially limited to the head and neck developed pulmonary disease, and none developed renal disease. Cumulatively, otitis media was more likely to be observed in patients with systemic disease (P = .04). Patients with localized (n = 12) and systemic (n = 12) GPA did not have significantly different rates of surgical interventions (0.55 vs. 0.72 surgical interventions/patient-year of follow-up, respectively, P = .19). CONCLUSIONS: GPA has a variety of head and neck manifestations, most commonly sinusitis, nasal disease, subglottic stenosis, and otitis media. GPA commonly progresses to involve additional sites, regardless of the extent of disease. These patients require frequent surgical intervention, and the clinician should remain vigilant for progression of disease.

Surface modifications of dental implants.

Dental implant surface technologies have been evolving rapidly to enhance a more rapid bone formation on their surface and hold a potential to increase the predictability of expedited implant therapy. While implant outcomes have become highly predictable, there are sites and conditions that result in elevated implant loss. This paper reviews the impact of macro-retentive features which includes approaches to surface oxide modification, thread design, press-fit and sintered-bead technologies to increase predictability of outcomes. Implant designs that lead to controlled lateral compression of the bone can improve primary stability as long as the stress does not exceed the localized yield strength of the cortical bone. Some implant designs have reduced crestal bone loss by use of multiple cutting threads that are closely spaced, smoothed on the tip but designed to create a hoop-stress stability of the implant as it is completely seated in the osteotomy. Following the placement of the implant, there is a predictable sequence of bone turnover and replacement at the interface that allows the newly formed bone to adapt to microscopic roughness on the implant surface, and on some surfaces, a nanotopography (<10(-9) m scale) that has been shown to preferably influence the formation of bone. Newly emerging studies show that bone cells are exquisitely sensitive to these topographical features and will upregulate the expression of bone related genes for new bone formation when grown on these surfaces. We live in an exciting time of rapid changes in the modalities we can offer patients for tooth replacement therapy. Given this, it is our responsibility to be critical when claims are made, incorporate into our practice what is proven and worthwhile, and to continue to support and provide the best patient care possible.

The use of mycobacterial adjuvant-based agents for immunotherapy of cancer.

A heat-killed preparation of Mycobacterium vaccae (SRL172) has been shown, in recent studies, to be effective in the treatment of adenocarcinoma of the lung and renal cell cancer. It is postulated that the mechanisms of this form of immunotherapy is, at least in part, due to immune regulation, reflected in the selective enhancement of Th1 and down-regulation of Th2 T cell activity. These beneficial effects are attributed to the ability of adjuvants in the bacterial cell walls to modify and optimise the response to antigens shared by the bacteria and stressed host tissues, resulting in the destruction of cancer cells by programmed cell death or apoptosis. The M. vaccae-induced apoptosis appears to be most effective against carcinomas, perhaps especially those of glandular tissue, in contrast to pyrexia-induced necrosis which is most effective against tumours of mesodermal origin. In view of the great range of adjuvants, especially in the genus Mycobacterium and related genera, it may prove possible to develop a range of immunotherapeutic agents with useful activity against a wide range of cancers.

Successful immunotherapy with Mycobacterium vaccae in the treatment of adenocarcinoma of the lung.

Immunotherapy with a heat-killed suspension of Mycobacterium vaccae (SRL172), given with chemotherapy, in a phase III trial against non-small-cell-lung cancer showed no improvement in the primary endpoint of survival over chemotherapy alone in the initial published analysis. Compliance was poor, with on average only 53% of patients receiving more than 2 injections in the SRL172 arm of the study. Quality of life was, however, improved in those receiving SRL172. Secondary analyses based on compliance with therapy showed that immunotherapy led to significantly improved survival times of patients with adenocarcinoma but, by contrast, had no beneficial effect on survival times of patients with squamous cell carcinoma. Survival of adenocarcinoma patients receiving SRL172 was increased by a mean of 135 days (p=0.0009, Kaplan-Meier log rank test) and survival after 4 or 5 doses of SRL172 showed a difference of greater than 100 days (p<0.05, Mantel-Hänszel log rank test) in the group receiving SRL172 in addition to chemotherapy. Despite the problems inherent in a secondary analysis, these results encourage further research on the role of killed preparations of adjuvant-rich micro-organisms, including saprophytic mycobacteria such as M. vaccae, and members of related genera in the therapy of a range of cancers.

Apatite/amelogenin coating on titanium promotes osteogenic gene expression.

Osteoblast differentiation and extracellular matrix production are pivotal processes for implant osseointegration or bone tissue engineering. We hypothesized that a biomimetic coating on titanium surfaces, consisting of apatite and amelogenin, would promote such processes. Human Embryonic Palatal Mesenchymal pre-osteoblasts were used as a model for the evaluation of cell adhesion and spreading patterns, as well as mRNA expression of certain osteoblastic gene products. Real-time PCR showed significant (p < 0.05) increase in expression of type I collagen, alkaline phosphatase, and osteocalcin from cells grown on titanium with an apatite/amelogenin composite, as compared with that from cells grown on a pure titanium or apatite coating only. Osteocalcin expression was specifically stimulated by amelogenin added to the culture media. Enhanced attachment and cell spreading were also observed. The biomimetic coating promoting cell adhesion and osteoblast differentiation may have great potential for future dental and biomedical applications.

Childhood atopy and allergic disease and skin test responses to environmental mycobacteria in rural Crete: a cross-sectional survey.

BACKGROUND: Through its powerful immunoregulatory effects, infection with atypical mycobacteria may exert a protective effect on the development of childhood allergic disease. OBJECTIVE: To examine the relationship between childhood atopy or allergic disease and previous infection with four species of atypical mycobacteria. METHODS: Eight hundred and six children aged 8-18 years and living in rural Crete--most of whom had had previous BCG immunization--underwent skin prick testing with 10 aeroallergens; their parents completed a standardized questionnaire relating to allergic disease. No less than 8 weeks later each child underwent intradermal skin tests with 0.1 mL solutions of four selected mycobacterial reagents (Aviumin C, Gordonin, Chelonin and Ranin I). RESULTS: Twenty-three percent of children were atopic on skin prick testing; far fewer had symptoms of asthma (5%) or hayfever in conjunction with a positive prick test to pollens (2%). Eighty percent of children had positive skin responses to one or more mycobacterial species. Among all children--and those with a BCG scar--there was no association between atopy or allergic symptoms and mycobacterial skin responses; among the few children without a BCG scar however those with positive mycobacterial responses were less likely to be atopic or to report allergic symptoms; these differences were not statistically significant. CONCLUSIONS: Our findings, in a population of BCG-immunized children, do not lend support to the suggestion that infection with atypical mycobacteria is protective against childhood allergic disease.

Issues and considerations in dental implant occlusion: what do we know, and what do we need to find out?

Implant dentistry continues to struggle with what are the appropriate occlusal concept(s) for implant-supported restorations. The biological and mechanical consequences of the loading environment leads to establishing and maintaining an implant interface in a wide variety of bone quality and quantity, implant and prosthesis designs. To the restorative dentist, the role of occlusion is more focused on extending the service life of the restoration and the connecting abutment(s) than protecting the osseous integration of the implant(s). This study reviews the relevant issues regarding implant occlusion along with implant and prosthesis design in order to provide optimal patient care.