bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Origin of Periodontal Infections
Authors: Genco R.J. , Zambon J.J. , Christersson L.A. 
Published: January 2017

Periodontal diseases are recognized as bacterial infections, and some forms are associated with specific organisms, such as Actinobacillus actinomycetemcomitans in juvenile periodontitis, and Bacteroides gingivalis and others in adult periodontitis. The source of the periodontal organisms, whether they are part of the indigenous or resident flora and overgrow to become opportunistic oral pathogens, or whether they are exogenous oral pathogens, is important to determine. The chain of periodontal infection, microbial agent(s) and their transmission, and host response are reviewed with respect to the role of A. actinomycetemcomitans in localized juvenile periodontitis and B. gingivalis in adult periodontitis. The present data lead us to hypothesize that some periodontal organisms may be exogenous pathogens. Prevention of periodontal diseases may be influenced by the knowledge of whether various forms are caused by opportunistic organisms or exogenous pathogens. If exogenous pathogens are responsible, prevention can be directed to intercepting transmission, thereby preventing colonization. On the other hand, if the organisms are opportunistic pathogens, prevention might be directed at interfering with initial acquisition of the flora earlier in life, as well as suppressing them to low levels consistent with health. For those exogenous periodontal infections, attempts at eradication and prevention of re-infection are likely to be effective. If the organisms are part of the indigenous flora, there is little hope of complete elimination of the organism. Criteria for distinguishing exogenous periodontal pathogens from opportunistic periodontal pathogens include the prediction that exogenous pathogens would be transient members of the oral flora associated with periodontal disease, likely to be comprised of one or a few clonal types, and intrinsically virulent. In contrast, opportunistic periodontal pathogens would likely be members of the indigenous flora and would overgrow. They would likely be comprised of many clonal types, and have an intrinsically low level of virulence.
Clinical Application of Tissue Reflectance Spectrophotometry to Periodontal Disease
Authors: Shizukuishi S. , Hanioka T. , Tsunemitsu A. 
Published: January 2017

Rapid, accurate, and non-invasive measurements of hemodynamics and oxygen utilization in gingiva are clinically important in evaluation of the severity of the inflammatory response in periodontal disease. In the present study, tissue reflectance spectrophotometry was used to examine gingiva in vivo to estimate hemoglobin concentration (Hb index) and the oxygen saturation level of hemoglobin in gingiva (HbSO2 index). Reflectance spectrophotometry was also used to examine these parameters in experimental periodontitis in dogs, and in patients with periodontal disease. Both in vitro and in vivo experiments confirmed that the Hb index was positively correlated with hemoglobin concentration in gingival tissue. The relationship between the HbSO2 index and PO2 in gingiva was a sigmoid curve resembling the hemoglobin-oxygen dissociation curve. In rapidly advancing periodontitis resulting from ligature placement in dogs, the Hb index was significantly enhanced, but the HbSO2 index was reduced. This reduction corresponded to increases in gingival inflammation during the experiments. Furthermore, in humans, the Hb index was significantly higher in inflamed gingiva than in clinically healthy gingiva. A lower HbSO2 index was also found in inflamed gingiva. These findings are consistent with congested blood vessels, impaired venous return, and localized hypoxia in inflamed gingival tissue. Tissue reflectance spectrophotometry is clinically useful in estimating blood volume and oxygen saturation in diseased gingiva.
X-Ray Micro-Analysis of the Mineralization Patterns in Developing Enamel in Hamster Tooth Germs Exposed To Fluoride in Vitro During the Secretory Phase of Amelogenesis
Authors: Lyaruu D.M. , Blijlevenz N. , Hoeben-Schornagel K. , Bronckers A.L.J.J. , Woltgens J.H.M. 
Published: January 2017

The developing enamel from three-day-old hamster first maxillary (M1) molar tooth germs exposed to fluoride (F-) in vitro was analyzed for its mineral content by means of the energy-dispersive x-ray micro-analysis technique. The aim of this study was to obtain semi-quantitative data on the F--induced hypermineralization patterns in the enamel and to confirm that the increase in electron density observed in micrographs of F-treated enamel (Lyaruu et al., 1986, 1987b) is indeed due to an increase in mineral content in the fluorotic enamel. The tooth germs were explanted during the early stages of secretory amelogenesis and initially cultured for 24 hr in the presence of 10 ppm F- in the culture medium. The germs were then cultured for another 24 hr without F-. In order to compare the ultrastructural results directly with the microprobe data, we used the same specimens for both investigations. The net calcium counts (measurement minus background counts) in the analyses were used as a measure of the mineral content in the enamel. The aprismatic pre-exposure enamel, deposited in vivo before the onset of culture, was the most hypermineralized region in the fluorotic enamel, i.e., it contained the highest amount of calcium measured. The degree of the F--induced hypermineralization gradually decreased (but was not abolished) in the more mature regions of the enamel. The unmineralized enamel matrix secreted during the initial F- treatment in vitro mineralized during the subsequent culture without F-. The calcium content in this enamel layer was in the same order of magnitude as that recorded for the newly deposited enamel in control tooth germs cultured without F-. From these results, and in combination with the ultrastructural data obtained in previous studies, it is concluded that in vitro: (1) F- treatment during the secretory phase of amelogenesis induces hypermineralization of the pre-exposure enamel; (2) F- decontrols or abolishes enamel crystal growth in length and promotes crystal growth in thickness, thus producing enamel hypermineralization; and (3) enamel matrix secreted during F- exposure retains its capacity to support crystal growth when F- is removed from the culture environment.
Side-Effects: Mercury Contribution to Body Burden From Dental Amalgam
Authors: Reinhardt J.W. 
Published: January 2017

The purpose of this paper is to examine and report on studies that relate mercury levels in human tissues to the presence of dental amalgams, giving special attention to autopsy studies. Until recently, there have been few published studies examining the relationship between dental amalgams and tissue mercury levels. Improved and highly sensitive tissue analysis techniques have made it possible to measure elements in the concentration range of parts per billion. The fact that mercury can be absorbed and reach toxic levels in human tissues makes any and all exposure to that element of scientific interest. Dental amalgams have long been believed to be of little significance as contributors to the overall body burden of mercury, because the elemental form of mercury is rapidly consumed in the setting reaction of the restoration. Studies showing measurable elemental mercury vapor release from dental amalgams have raised renewed concern about amalgam safety. Mercury vapor absorption occurs through the lungs, with about 80% of the inhaled vapor being absorbed by the lungs and rapidly entering the bloodstream. Following distribution by blood circulation, mercury can enter and remain in certain tissues for longer periods of time, since the half-life of excretion is prolonged. Two of the primary target organs of concern are the central nervous system and kidneys.
Documented Clinical Side-Effects to Dental Amalgam
Authors: Ziff M.F. 
Published: January 2017

Since all dental restorative materials are foreign substances, their potential for producing adverse health effects is determined by their relative toxicity and bioavailability, as well as by host susceptibility. Adverse health effects to dental restoratives may be local in the oral cavity or systemic, depending on the ability of released components to enter the body and, if so, on their rate of absorption. The medical scientific community is now in general agreement that patients with dental amalgam fillings are chronically exposed to mercury, that the average daily absorption of mercury from dental amalgam is from 3 to 17 micrograms per day, and that the amalgam mercury absorption averages 1.25-6.5 times the average mercury absorption from dietary sources (World Health Organization, 1991). The health significance of this chronic mercury exposure is now being investigated by several medical research groups.
Dental Amalgam and Mercury Vapor Release
Authors: Osborne J.W. 
Published: January 2017

Dental diseases are among the most common ailments, and dentists in the United States spend over 50% of their time in dental practice rebuilding carious, malformed, and traumatically injured teeth. It is logical, therefore, that the majority of the dental school curriculum is devoted to the diagnosis, prevention, and treatment of teeth with anomalies. Dentists have several choices of materials they can use to accomplish the task of rebuilding teeth. Besides amalgam, they have ceramic materials, resin composites, base-metal and noble casting alloys, and glass-ionomer cements to use to restore the posterior dentition. Each of these restorative materials has advantages and disadvantages, and the clinical judgment as to when a particular material should be used is given a high priority in dental education. Amalgam is the most widely used of these restorative materials, with 92% of dentists listing it as the material of choice in the posterior of the mouth (Clinical Research Associates, 1990). Dentists have been placing amalgams for over 150 years in the US. They placed 150 million last year, which represents over 75 tons of amalgam alloy. The reasons that dentists use this restorative material so frequently are its durability, ease of manipulation, and low cost. Numerous clinical studies have been conducted on the serviceability of amalgam. Most of these have been on the old, low-copper alloys, and results indicate that they last from 8 to 15 years (Bailit et al,, 1979; Osborne et al., 1980; Qvist et al., 1986). In the past 20 years, vast improvements have been made in amalgams with the development of the high-copper systems. Clinical studies initiated in the 1970's are reporting that the well-placed high-copper amalgam will last over 30 years (Laswell et al., 1989; Letzel et al., 1989; Osborne and Norman, 1990; Osborne et al., 1991). The ease with which amalgam is manipulated has no equal. Placement of amalgam takes only 20-50% of the time it takes to restore a tooth with other materials. For the amalgam, this cost in placement time and the cost to purchase the material are considerably less. The one factor that amalgam does not have in its favor is esthetics. The other-restorative materials, frankly, look better.
Problems and Benefits Associated With Restorative Materials: Side-Effects and Long-Term Cost
Authors: Mjör Ivar A. 
Published: January 2017

The paper reviews data on biological side-effects of dental materials on patients and also on personnel who routinely handle the materials. The incidence of adverse effects is low-in one study indicated to be 1:700 for all types of treatments. For individual types of materials, it will be significantly lower, and for restorative materials, probably in the 1 : 10,000 to 1:20,000 range. Allergic reactions are the most common type of adverse effect of dental materials. Lichenoid reactions on the oral mucous membrane adjacent to amalgam restorations are the most frequently encountered side-effects for a specific group of restorative materials. Cost analyses were based on reports of longevity of different restorations and the cost of restorations at the time of placement. Amalgam restorative therapy was more cost-effective than composite restorations and gold castings.
Dental Tissue Effects of Fluoride
Authors: Fejerskov O. , Larsen M.J. , Richards A. , Baelum V. 
Published: January 2017

It is now well-established that a linear relationship exists between fluoride dose and enamel fluorosis in human populations. With increasing severity, the subsurface enamel all along the tooth becomes increasingly porous (hypomineralized), and the lesion extends toward the inner enamel. In dentin, hypomineralization results in an enhancement of the incremental lines. After eruption, the more severe forms are subject to extensive mechanical breakdown of the surface. The continuum of fluoride-induced changes can best be classified by the TF index, which reflects, on an ordinal scale, the histopathological features and increases in enamel fluoride concentrations. Human and animal studies have shown that it is possible to develop dental fluorosis by exposure during enamel maturation alone. It is less apparent whether an effect of fluoride on the stage of enamel matrix secretion, alone, is able to produce changes in enamel similar to those described as dental fluorosis in man. The clinical concept of post-eruptive maturation of erupting sound human enamel, resulting in fluoride uptake, most likely reflects subclinical caries. Incorporation of fluoride into enamel is principally possible only as a result of concomitant enamel dissolution (caries lesion development). At higher fluoride concentrations, calcium-fluoride-like material may form, although the formation, identification, and dissolution of this compound are far from resolved. It is concluded that dental fluorosis is a sensitive way of recording past fluoride exposure because, so far, no other agent or condition in man is known to create changes within the dentition similar to those induced by fluoride. Since the predominant cariostatic effect of fluoride is not due to its uptake by the enamel during tooth development, it is possible to obtain extensive caries reductions without a concomitant risk of dental fluorosis.
Current Techniques for Measuring Dental Fluorosis: Issues in Data Analysis
Authors: Kingman A. 
Published: January 2017

The currently popular scoring systems used to diagnosis fluorosis use different measurement units, evaluate variable numbers of sites per person, and involve non-comparable groupings of clinical symptoms. Although none of these factors is related to the level of fluoride exposure in the examined population, their combined effect produces fluorosis prevalence values for a population which vary considerably among and within these scoring systems. Intrinsic factors for a scoring system include the inclusion of a questionable category, the minimal level of fluorotic involvement, and the number of affected sites within a subject required for case definition. Thus, a case definition of fluorosis for each scoring system, although not mandatory, would certainly be desirable so that dental epidemiologists and clinical investigators can interpret fluorosis scores relative to risk assessment. On the other hand, ratios of fluorosis prevalence magnitudes, as evidenced by odds ratios, can be more stable between scoring systems when groups with different fluoride exposure levels are compared. There is a strong correlation between extent and specific measures of fluorosis severity for Dean's Index (DI) and the Tooth Surface Index of Fluorosis (TSIF) scoring system, as well as within each scoring system separately. Parallel patterns in fluorosis severity were found among groups with different fluoride exposures for the DI and TSIF scoring systems. The effects of fluoride exposure on severity levels of fluorosis may be better understood by using relative measures rather than by using differences in severity levels.
Endangered species: science writers in the Canadian daily press
Authors: Saari Mary-Anne , Gibson Candace , Osler Andrew 
Published: January 2017

The last comprehensive study of Canadian science journalists and science reporting was done over 20 years ago (Dubas and Martel 1973). A more recent content analysis of seven major Canadian dailies found most science stories are “hard” news in style and originate from wire sources (Einsiedel 1992). This 1994 survey of 105 of Canada's daily English-language newspapers and their commitment to science journalism revealed a general weakening and dilution of reporter allocation. Over 50 percent of Canadian dailies did not allocate a science reporter. Only 18 full-time science reporters were identified. A follow-up of 45 journalists covering science at least half-time revealed most covered science policy. The vast majority had no science training. Time problems and competing demands hindered professional development. Confirming suggestions of previous literature, this study also indicates the Canadian daily newspaper structure is not supportive of the style of reportage required for quality science writing, nor of the development of such writers.
An Epidemiologic Perspective of Saliva Flow Rates as Indicators of Susceptibility to Oral Disease
Authors: Billings Ronald J. 
Published: January 2017

Catastrophic hyposalivation significantly increases susceptibility to dental caries in dentate individuals and may cause the expression or exacerbation of other oral diseases/disorders as well. The effect of subcatastrophic hyposalivation on susceptibility to caries or other diseases/disorders is less well understood. The aim of this study (part of a larger study on the prevalence of hyposalivation) was to determine the prevalence and to measure the association of oral pathologic conditions with unstimulated and stimulated whole saliva flow rates. Only 6.3% of all study participants had significantly diminished unstimulated (<0.05 ml/min) and stimulated (<0.50 ml/ min) saliva flow rates. A total of 15 individuals were encountered with oral pathologic lesions and none of these lesions were associated with hyposalivation. Although the prevalence of coronal caries, root surface caries, abrasion, and erosion tended to increase as salivary flow decreased, when the effect of age was considered no significant differences were present. These data suggest that low saliva flow rates alone, at least from an epidemiologic perspective, do not have a clinically relevant effect on susceptibility to oral diseases/disorders.
Effect of Clarithromycin on Steady-State Digoxin Concentrations
Authors: Tanaka Hideko , Matsumoto Kana , Ueno Kazuyuki , Kodama Mayumi , Yoneda Kohji , Katayama Yoshiaki , Miyatake Kunio 
Published: January 2017

OBJECTIVE: To evaluate the magnitude and dose-relatedness of the effect of clarithromycin on the pharmacokinetics of digoxin, and to compare the effects of clarithromycin with those of P-glycoprotein inhibitors. METHODS: Eight Japanese inpatients with congestive heart failure participated in this study. Each patient received oral digoxin therapy for at least 7 days and were coadministered oral clarithromycin to prevent or treat pneumonia. To evaluate the effects of clarithromycin on the pharmacokinetics of digoxin, digoxin concentrations were compared before and after coadministration of clarithromycin. RESULTS: Digoxin concentrations were higher after coadministration of clarithromycin in all patients (before, 0.838 ± 0.329 ng/mL; after, 1.36 ± 0.619 ng/mL); (p < 0.005). A significant correlation was observed between the dose of clarithromycin and the percentage of increase in the digoxin concentration. CONCLUSIONS: Digoxin concentrations increased during concomitant administration of clarithromycin, and this effect was dose-dependent on clarithromycin. The percentage increase in digoxin concentrations after the usual oral dose of clarithromycin (400 mg/d) is approximately 70%. Therefore, digoxin concentrations must be monitored carefully after coadministration of clarithromycin, and the doses of digoxin may need readjustment in patients who are concomitantly receiving clarithromycin.
Pseudo-Parkinson Disease Secondary to Ritonavir–Buspirone Interaction
Authors: Clay Patrick G , Adams Molly M 
Published: January 2017

OBJECTIVE: To report a case of Parkinson-like symptoms appearing in a patient after introduction of ritonavir to buspirone therapy. CASE SUMMARY: A 54-year-old HIV-positive white man presented to the clinic with a 2-week history of ataxia, shuffling gait, cogwheel rigidity, resting tremor, and sad affect with masked features. This patient had been receiving high-dose buspirone (40 mg every morning and 30 mg every evening) for 2 years prior to the introduction of ritonavir/indinavir combination therapy (400 mg/400 mg twice daily) 6 weeks prior to initiation of the above symptoms. Buspirone was decreased to 15 mg 3 times daily, ritonavir/indinavir was discontinued, and amprenavir 1200 mg twice daily was added. The patient's symptoms began to subside after 1 week, with complete resolution after about 2 weeks. The patient continued to receive buspirone for an additional 12 months without recurrence of symptoms. DISCUSSION: This is the first reported interaction of buspirone and antiretrovirals. Buspirone, extensively metabolized by CYP3A4, was likely at supratherapeutic levels due to the inhibitory effect of ritonavir and, secondarily, indinavir. The Parkinson-like symptoms developed rapidly and severely, impacted this patient's quality of life, and necessitated significant clinic expenditures to identify this drug–drug interaction. CONCLUSIONS: This case demonstrates a severe drug–drug interaction between buspirone and ritonavir and further demonstrates the need for awareness of the metabolic profile for all agents an HIV-infected patient is receiving.
Macular Exanthema Due to Fumaric Acid Esters
Authors: Guenther Claudia H , Wozel Gottfried , Laske Jörg , Aschoff Roland , Meurer Michael 
Published: January 2017

OBJECTIVE: To report a case of an unusual skin reaction to fumaric acid esters (FAE). CASE SUMMARY: A 68-year-old white woman who was treated with FAE for 4 days for lichen planus developed generalized pruritic exanthema. This was suspected to be an allergic drug reaction to FAE, and the treatment was discontinued. After 48–72 hours, the exanthema resolved completely. An objective causality assessment revealed that the adverse drug event was probable. As skin testing for diagnostic purposes is not feasible with FAE, the drug-related origin of the exanthema was confirmed by oral rechallenge with FAE. DISCUSSION: The effectiveness of FAE in the systemic treatment of psoriasis vulgaris has been proven by controlled clinical trials. The compound has been shown to be tolerable and safe even during prolonged treatment. The most frequent adverse effects are gastrointestinal symptoms and flushing, which typically occur 4–6 hours after administration of the drug. Allergic reactions to FAE have not yet been reported. Since the patient was rechallenged with the suspected drug, we could confirm the allergic origin of the exanthema. CONCLUSIONS: The occurrence of allergic skin reaction should be considered in patients receiving treatment with FAE.
Gabapentin for the Treatment of Tremor
Authors: Faulkner Michele A , Bertoni John M , Lenz Thomas L 
Published: January 2017

OBJECTIVE: To review the use of the antiepileptic drug gabapentin for the treatment of various types of tremor. DATA SOURCES: A search of biomedical literature was completed through MEDLINE and EMBASE (1993–May 2002) to identify all clinical trials pertaining to the use of gabapentin for the treatment of tremor in humans. DATA SYNTHESIS: Outcome data from the few published studies have varied widely. Patient groups have been small, and conclusions have been based largely on subjective patient and investigator ratings. CONCLUSIONS: A trial of gabapentin is warranted in patients who fail therapy with traditional agents. Improvement should be measured by a patient's perceived functional ability.