The role of stigma in health and functioning in chronic pain: Not just catastrophizing.

BACKGROUND: People with chronic pain are frequently exposed to stigma, which is typically distressing and may lead to internal stigmatizing thoughts. The thought content associated with stigma has similarities to pain catastrophizing, although these concepts differ in that stigma is arguably more social in origin. Stigma can be measured by the Stigma Scale for Chronic Illness - 8-item version (SSCI-8). In this study, we first demonstrate the validity of this measure in Swedish. We then examine the role of stigma in the health and functioning of people with chronic pain, particularly beyond the role played by pain catastrophizing. METHODS: Adult participants (N = 404) with chronic pain recruited online completed measures of pain, stigma, catastrophizing, pain interference, work and social adjustment and depression on two occasions. RESULTS: A one-factor solution had an overall good model fit as long as residuals were allowed to covary, indicating some redundancy in the items. The SSCI-8 demonstrated good internal consistency and moderate temporal stability, and SSCI-8 scores demonstrated medium-to-large correlations with the measures of health and functioning. Furthermore, stigma was found to significantly contribute to explained variance in pain interference, work and social adjustment and depression, uniquely adding to the explained variance in these outcomes even after accounting for pain catastrophizing. CONCLUSIONS: The SSCI-8 provides an adequate measure to capture stigma experiences. Stigma is uniquely associated with pain-related outcomes and should be further considered in pain research and clinical practice in the future. SIGNIFICANCE: This study points to the importance of a social perspective on pain-related outcomes. We may need to more fully appreciate the way that people with chronic pain are treated by both health care providers and others can have an impact on their well-being. Potential negative impacts of stigmatizing responses to people with chronic pain are highlighted by the current results.

First Report of Bean Common Mosaic Necrosis Potyvirus (BCMNV) Infecting Common Bean in California.

During the 1996 growing season (June to September) an outbreak of bean common mosaic was detected in a navy bean field (cv. Snow Bunting) in Colusa County, CA. Early field inspections (August 1996) revealed an incidence of 5 to 10% infection, whereas a late field inspection (September) showed an incidence of 70 to 90% infection. Enzyme-linked immunosorbent assay (ELISA) was performed on 18 leaf samples from symptomatic plants collected from this field with two monoclonal antibodies (Mab): Mab I-2, which detects bean common mosaic necrosis virus (BCMNV) strains (previously necrotic or serotype A bean common mosaic potyvirus [BCMV] strains), and Mab 197, which detects BCMV strains (previously non-necrotic or serotype B BCMV strains) and BCMNV (3). ELISA results indicated BCMNV infection in all 18 samples. In order to confirm ELISA results and to further characterize the viral isolate(s), primary leaves of the differential bean cvs. Black Turtle Soup (BTS) T-39, Topcrop, Amanda, and Sutter Pink were inoculated mechanically with sap prepared from the same leaves used for ELISA. Within 1 week, BTS T-39 and Topcrop plants showed necrotic spots on inoculated leaves and systemic necrosis and death (black root rot symptoms), Sutter Pink showed typical systemic mosaic symptoms, and Amanda showed necrotic spots and restricted vein necrosis on inoculated leaves. These reactions were consistent with infection by the NL-3 strain of BCMNV (1). Reverse transcriptase-polymerase chain reaction was used to amplify a portion of the genome of the virus that contains the 3' end of the coat protein (CP) gene and the 3' untranslated region (UTR). A DNA fragment of approximately 670 bp was amplified and DNA sequence analysis revealed that the nucleotide sequences of the 3' end of the CP and the UTR region of the California BCMNV isolate were 98 and 94% similar to those of the Michigan isolate of the BCMNV NL-3 strain (2), respectively. Together, these results suggest that the outbreak of bean common mosaic in the cv. Snow Bunting navy beans was caused by a pathogroup VI BCMNV isolate, and DNA sequence information suggests that it is similar to the NL-3 strain of BCMNV. This is the first report of BCMNV in California. References: (1) E. Drijfhout et al. Neth. J. Plant Pathol. 84:13, 1978. (2) G. F. Fang et al. Virus Res. 39:13, 1995. (3) G. I. Mink et al. Arch. Virol. S:397, 1992.

Microhardness and porosity of Class 2 light-cured composite restorations cured with a transparent cone attached to the light-curing wand.

A new technique for curing class 2 composite fillings was investigated with respect to microhardness and porosity in the cervical part of the restorations. The technique is based on a plastic transparent cone that is attached to the curing wand. Before polymerizing the cervical portion, the cone is pressed down into the material in the direction of the floor of the approximal box. When the light is activated, it concentrates in the tip of the cone, from where it is distributed into the composite material. In order to compare this technique with conventional curing, standardized class 2 cavity preparations were made in brass blocks. Four different composite materials were used for 20 restorations each: Heliomolar, Herculite XR, Occlusin, and P-50. Ten restorations of each material were cured using the conventional technique (in two portions), and in the remaining 10 restorations the cervical portion was cured with the transparent cone. The irradiation time was 60 seconds in all instances. The Vickers hardness of the cervical approximal surfaces was measured after one and 24 hours. The surfaces were photographed in a stereomicroscope, and the numbers of porosities were counted on black-and-white prints.(ABSTRACT TRUNCATED AT 250 WORDS)

Temperature rise during root canal preparation--a possible cause of damage to tooth and periodontal tissue.

Temperature rise on the surface of extracted human premolar roots was recorded during root canal preparation using a thermo-couple. It was found that time, pressure exerted on the reamer, type of reamer and rotational speed influenced the temperature rise. Starting from about 30 degrees C temperatures up to 87 degrees C were recorded, generally in less than 50 seconds' working time, using routine instrument and technique. Possible effects of this temperature rise on tooth substance, periodontal membrane and supporting bone are discussed.

A follow-up study of screwpost-retained amalgam crowns.

A follow-up study of amalgam crowns retained with brass screwposts (Dentatus) has been performed. The teeth had been restored by undergraduates at the Department of Cariology, School of Dentistry, Stockholm, during the years 1970-1976. Radiographs of the teeth made at the time of insertion of posts were available in all cases. The material comprised 56 teeth with altogether 69 screwposts. Average observation time was 7.8 years. Anamnestic data were collected and clinical and radiographic investigations of the restored teeth and surrounding tissues were carried out. Of the 56 teeth, 8 teeth containing altogether 11 screwposts had been lost by extraction. Annotations from the treating dentists were available in all cases and showed that five of the extractions had been necessary because of extensive caries, one because of parodontitis and two because of root fractures. No corrosion of screwposts had been observed in the fractured teeth. The anamnestic investigation revealed sporadic tenderness and metallic taste in only a few cases. The most frequent clinical findings were discoloration and pitting of amalgam surfaces and discoloration of tooth substance and gingiva. The discolorations of the gingiva were related to restorations extending below the gingival margin. No clinical or radiographic signs of corrosion of screwposts were found in the investigated teeth.

Laser-induced fluorescence from sound and carious tooth substance: spectroscopic studies.

Fluorescence spectra of dentine and enamel illuminated with laser light of wavelengths of 337, 488, 515 and 633 nm respectively were recorded. The fluorescence obtained by illumination with UV laser light at 337 nm had a peak at about 400 nm in dentine as well as enamel. Compared to intact enamel the fluorescence from enamel with initial carious lesions was of lower intensity and had a slight red shift. No fluorescence within the visible range was obtained by illumination with a low power He-Ne laser at 633 nm. Illumination at 488 nm produced fluorescence with a peak at about 540 nm in dentine as well as enamel. The difference in the intensity of fluorescence between sound and carious enamel was generally greater at this wavelength than at any of the others tried, and the red shift from the carious enamel was also more pronounced. Illumination at 515 nm produced fluorescence of similar wavelengths but with much less difference between intact and carious enamel. It was concluded that illumination at 488 nm was the most suitable wavelength of those investigated for the detection of initial carious lesions by the fluorescence technique.

Intradental nerve activity and jaw-opening reflex in response to mechanical deformation of cat teeth.

Mechanical stress was applied to canine teeth in anaesthetized cats to excite intradental A-fibres and to produce digastric muscle EMG responses. Activity in the intradental sensory units was recorded by two electrodes, one inserted in a dentinal cavity, the other in contact with the gingival sulcus. A pneumatically driven piston was used to cause a mechanical stress (10-150 N) on the stabilized tooth crown for 30 s, with instantaneous onset and release. Application of a load of 30 N produced a momentary burst of impulses in 2 of 12 teeth; 8 out of 10 teeth responded when 150 N was used. Digastric EMG responses were obtained at and above 60 N. Removal of the coronal pulp or cooling of the tooth crown with ethyl chloride abolished this reflex, whereas percussion of the tooth still produced a digastric response. Our results suggest that load-induced deformation of teeth activates intradental sensory mechanisms and a reflex withdrawal reaction unrelated to periodontal stimulation.

Electrical impedance for estimation of irritation in oral mucosa and skin.

Our aim is to establish an objective, easy-to-use technique to evaluate tissue irritation in vivo using non-invasive electrical impedance measurements. Such a technique would facilitate testing the biocompatibility of various materials, and also in quantifying skin diseases and other processes involving structural changes. It has been found that irritation of the oral mucosa not clinically or histologically discernible could be detected with a simple device based on electrical impedance techniques. Originally, the key problem was to focus the probing electrical field in order to minimize artefacts emanating from tissue layers of no interest. The device was then refined and applied to skin testing. It was found that irritation effects far below the limit of the commonly used visual readings could be detected. In this case, it is desirable to exclude from the measurement tissue layers with no diagnostic information, or at least reduce their influence. In this paper, the essential steps of the development of a multi-frequency depth selective device are reviewed.

Initial caries diagnosis in rat molars, using laser fluorescence.

Scoring of enamel caries in rat molars in ordinary light and in laser fluorescence was compared. Fifty rats were infected with Streptococcus mutans; 5 served as control rats, and the other 45 were fed a cariogenic diet for 15-20 days. With Keyes's system, the total enamel caries score for 35 of the test rats was 29.1 lesions per rat (l/r) in ordinary light and 39.6 l/r in laser fluorescence. The corresponding scores for fissure caries were 15.9 l/r and 21.6 l/r, respectively. Fissure caries scores of thin, longitudinal, central sections from the molars of the 10 remaining test rats were 18.0 l/r in ordinary light, 21.4 l/r in laser fluorescence, and 17.1 l/r in microradiographic analysis. In conclusion, the use of laser fluorescence improves scoring of early enamel carious lesions in rat molars, offering potential reductions in test time and/or sucrose load in animal caries research.

Effects of egg yolk testosterone on growth and immunity in a precocial bird.

In oviparous vertebrates, maternal steroid allocation to eggs can have important fitness consequences for the offspring. However, elevated testosterone levels are not only associated with beneficial postnatal effects, such as enhanced growth and high social status, but may also entail costs by suppressing the immune system. In this study, testosterone levels in eggs of Chinese painted quail (Coturnix chinensis) were experimentally manipulated to evaluate its effects on growth and immunocompetence. Testosterone did not affect embryonic development, body size or growth during the first 20 days. However, elevated testosterone levels during embryonic development were immunosuppressive for chicks with inherently higher growth rate. Adaptive scenarios where only beneficial effects of increased testosterone levels are considered may therefore need to be re-evaluated.

Strength and setting behavior of resin-modified glass ionomer cements.

Diametral tensile strength (DTS), fracture strength, and Vickers microhardness were tested in three resin-modified glass ionomer cements (GICs), one chemically set GIC, and one dental composite. For the DTS studies test discs were immersed in deionized water at 37 degrees C for 10 min, 1 day, and 28 days, respectively. Cured discs were also implanted in back muscles of rats for 28 days before testing. The effects of light irradiation time and delayed curing on the DTS of the cements were also studied. Significantly higher strength was observed in the resin-modified GICs in comparison with the chemically set GIC at all observation period. K71 showed the highest strength among the GICs. No strength reductions were detected after 28 days for the specimens in vivo. An illumination time of 20 sec was enough to obtain final strength in the PFA and K71 specimens, and 40 sec was needed in the VI specimens. The strength of the resin-modified GICs when light-cured was significantly higher than when the same cements were allowed to set without irradiation. The microhardness of the light-cured GICs was similar to that of the dental composite. Considering the improved fracture strength and surface hardness, it was concluded that the resin-modified GICs present an interesting material for further development.

Factors influencing shear strength of incrementally cured composite resins.

Factors influencing the shear strength of incremental curing of three different composite resins were examined. The first increment was cured under different surface conditions, in air, or under a coverglass. A separate experiment studied the effect of curing in nitrogen atmosphere. There was no difference in the shear strength of the specimens if the first increment was created in air or under a coverglass. One material (Heliomolar RO) showed higher shear strength when cured in increments and one when bulk-cured (Herculite XR). Curing increments in a nitrogen atmosphere increased the shear strength for two of the three materials tested (P50 and Heliomolar). The results showed that the bond strength between the increments of composites was influenced by the surface properties of the composites themselves after they had been cured under the different conditions; it was also affected by the inherent chemical and physical properties of the materials utilized.

Influence of paste temperature at curing on conversion rate and bending strength of light-cured dental composites.

Pastes of three dental composites were tempered to 20 degrees C, 37 degrees C and 60 degrees C. Test specimens (22 x 2 x 2 mm) were cured by light and stored in deionized water. Three-point bending strength was measured after 1 h and after 24 h. Degree of conversion on the surface exposed to the curing light and the opposite surfaces at the bottom of the mould was analysed by Fourier transform infrared (FTIR) after 1 h. After 1 h, specimens produced using the pastes cured at 60 degrees C showed significantly higher bending strength than the specimens produced using pastes cured at 20 degrees C and 37 degrees C. However, after 24 h the composites pretempered at the lower temperatures had developed the same level of bending strength as the composites cured at 60 degrees C. An increase in the degree of conversion with increased paste temperature was found in all materials after 1 h.

Fluorescence in dissolved fractions of human enamel.

Fluorescence induced by laser light is useful in early detection of enamel caries. The present work studied the fluorescence emission pattern in dissolved human enamel and in different molecular weight fractions obtained after gel chromatography or dialysis followed by ultrafiltration. For comparison, solutions of synthetic hydroxyapatite and bovine enamel were used. When the entire emission and excitation spectra of the corresponding excitation and emission wavelengths in the solutions of human enamel and bovine enamel were compared, no distinct differences were found between the solutions. With excitation at 375 nm, emission peaks were found at 460 and 560 nm, indicating the presence in human enamel solution of two different chromophores, unevenly distributed over the molecular weight fractions. The 460-nm and the lower 560-nm fluorescence peaks seem to be derived from both organic and inorganic components. The inorganic substances contributing to both the 460-nm and 560-nm peaks were incorporated in complexes. The 560-nm emission peak elucidates part of the basis of the laser fluorescence method.

In vitro fluoride uptake by enamel and dentin. A comparative study of two varnishes.

The uptake of fluoride in enamel and dentin after application of an experimental fluoride varnish has been studied and compared with the uptake from a commercially available varnish (Duraphat). Each varnish was applied to 10 extracted human cuspid teeth. Successive etchings with perchloric acid were carried out separately in enamel and root dentin to obtain samples at three different depths. The concentrations of fluoride and calcium in the samples were determined, and the fluoride uptake was calculated. The experimental varnish gave a significantly greater fluoride uptake at all three sample depths in both enamel and dentin.

Flexure strength of resin-modified glass ionomer cements and their bond strength to dental composites.

The flexure strength of three resin-modified glass ionomer cements and one conventional glass ionomer cement and their bond strength to dental composites were studied by measuring the three-point bending and the shear strengths. The bond strengths between the dental composite and the resin-modified glass ionomer cements were dependent on the curing modes. Resin-modified glass ionomer cements bonded significantly more strongly to cured dental composites than dental composites bonded to cured resin-modified glass ionomer cements. However, the dental composites showed a significantly stronger bonding to the resin-modified glass ionomer cements than to the cured conventional glass ionomer cement, to which the dental composite did not adhere without acid etching. The flexure strengths of the resin-modified glass ionomer cements were significantly improved compared with the conventional one but were still significantly lower than that of the dental composites.

Strategies for improving the assessment of dental fluorosis: focus on optical techniques.

In its milder forms, enamel fluorosis is characterized clinically by diffuse opacities. The appearance is due to optical properties of a subsurface or surface porous layer with lower mineral content. These areas usually have texture and color similar to those of initial caries lesions but generally another shape and location. Therefore, several optical methods, previously used to diagnose initial caries lesions, were applied to fluoride-induced opacities on extracted premolars and on incisors of four subjects in vivo. These methods included light-scattering measurements, white light illumination, violet light illumination, ultraviolet illumination, and laser fluorescence. Video images were captured with a charge-coupled-device (CCD) camera, digitized, and computer-processed. It is concluded that the light-scattering monitor can be used for the determination of the local porosity of fluorotic enamel and that the laser fluorescence method might be developed into a method applicable for the assessment of the severity of enamel fluorosis.

Evaluation of a model for short-term clinical testing of cariogenicity.

Conventional mirror and probe examination and laser fluorescence were used to score caries-like alterations on the buccal surfaces of posterior teeth in 60 panelists, allotted to one of three groups. All subjects refrained from oral hygiene for five days. In one group each subject consumed 12 sucrose candies daily between meals and in the second group each subject similarly consumed 12 palatinose (isomaltulose) candies. The third group served as a control. At the end of the experimental period the tooth surfaces reexamined. Conventional and laser fluorescence scoring techniques showed an increase in the number of caries-like alterations for all groups, but there were no significant differences between the groups. For all groups, the laser method gave significantly greater scores throughout. The findings imply that certain aspects of the early development of enamel caries in subjects regularly using fluorides must be considered in the design of a short-term cariogenicity test. It is concluded that sensitive quantitative methods for the registration of caries are necessary in such tests.

A new method for in vivo quantification of changes in initial enamel caries with laser fluorescence.

A new method for the in vivo assessment of changes in initial enamel caries lesions was developed and tested. A CCD camera equipped with a high-pass filter (lambda > 520 nm) collects the fluorescence image of carious teeth, illuminated intraorally with diffuse laser light (lambda = 488 nm). Incipient lesions show a loss in fluorescence to be expressed as a percentage of fluorescence radiance of sound tissue. A PC program (Inspektor, model QLF 1.0) is used for display, storage, and subsequent analysis of images. To enable the calculation of fluorescence loss, the fluorescence of sound tissue at the lesion site is reconstructed from the radiances of sound tissue bordering the lesion. This method was tested on 19 visually sound buccal surfaces in vivo. The differences between actual and reconstructed radiance was -1.6 +/- (SD) 1.1%, over areas varying between 8 and 14 mm2. The repeatability of the caries quantification was tested by measuring one arrested initial caries lesion 25 times in vivo. The lesion area was 0.56 +/- 0.20 mm2, and the loss of fluorescence was 17.6 +/- 0.7%, corresponding to a lesion depth of 17 +/- 2 microns. The new quantitative method was applied for the testing of an in vivo caries model using plaque-accumulating brackets on premolars scheduled for extraction. Videoimages were recorded in vivo before bracketing and 0, 2, 3, and 5 weeks after debracketing. Clear changes between the different time points were recorded for both lesion size and mineral content.(ABSTRACT TRUNCATED AT 250 WORDS)