On-fiber high-resolution photonic nanojets via high refractive index dielectrics.

In this manuscript, we present high spatial resolution focusing of electromagnetic waves at telecommunication wavelengths (λ0 = 1.55 µm) by using high-refractive index mesoscale dielectrics placed at the end of an optical fiber. Our approach exploits photonic nanojets (PNJs) to achieve high-intensity, spatially narrow focal spots. The response of the device is evaluated in detail considering 2-dimensional (2D) and 3-dimensional (3D) configurations using high-index mesoscale cylindrical and spherical dielectrics, respectively, placed on top of an optical fiber. It is shown how the PNJs can be shifted towards the output surface of the mesoscale high-index dielectric by simply truncating its 2D/3D cylindrical/spherical output profile. With this setup, a PNJ with a high transversal resolution is obtained using the 2D/3D engineered mesoscale dielectric particles achieving a Full-Width at Half-Maximum of FWHM = 0.28λ0 (2D truncated dielectric), and FWHMy = 0.17λ0 and FWHMx = 0.21λ0 (3D truncated dielectric). The proposed structure may have potential in applications where near-field high spatial resolution is required, such as in sensing and imaging systems.

Pain and the Montreal Cognitive Assessment (MoCA) in Aging.

OBJECTIVE: The present study aimed to determine whether specific cognitive domains part of the Montreal Cognitive Assessment (MoCA) are significantly lower in community-dwelling older adults with chronic pain compared with older adults without pain and whether these domains would be associated with self-reported pain, disability, and somatosensory function. DESIGN: Secondary data analysis, cross-sectional. SETTING: University of Florida. SUBJECTS: Individuals over 60 years old enrolled in the Neuromodulatory Examination of Pain and mobility Across the Lifespan (NEPAL) study were included if they completed the MoCA and other study measures (n = 62). Most participants reported pain on most days during the past three months (63%). METHODS: Subjects underwent a health assessment (HAS) and a quantitative sensory testing (QST) session. Health/medical history, cognitive function and self-reported pain measures were administered during the HAS. Mechanical and thermal detection, and thermal pain thresholds were assessed during the QST session. RESULTS: Older adults with chronic pain had lower MoCA scores compared with controls on domains of executive function, attention, memory, and language (P < 0.05). The attention and language domains survived adjustments for age, sex, education, depression, and pain duration (P < 0.05). Attention was significantly associated with all pain characteristics including pain intensity and disability, while executive function was associated with mechanical detection (P < 0.05). CONCLUSION: Our results support previous findings that individuals with chronic pain tend to show poorer cognitive functioning compared with pain-free controls in domains of attention and executive function. Our findings also extend these findings to community-dwelling older adults, who are already most vulnerable to age-related cognitive declines.

Real-time image restoration for space-object imaging.

Military applications such as optical space surveillance and civilian applications such as astronomical imaging often require adaptive optics to compensate images of distant objects that are dynamically blurred by atmospheric turbulence. Many factors prevent adaptive optics (AO) from restoring a fully diffraction-limited image quality. Accordingly, restoration methods such as blind deconvolution and contrast enhancement are applied to further improve such imagery. Sometimes, the restoration must take place with low-latency and real-time frame rates because video imagery needs to be viewed promptly. This paper describes a procedure for conducting multi-frame blind deconvolution on experimental AO-compensated imagery in real time. In the procedure, registration and windowing enabled deconvolution, and subsequent enhancements improved the visibility of object features for visual assessment. This process features "multi-frame online blind deconvolution," which is a modification of the previously published "online blind deconvolution." This modified algorithm jointly processes multiple frames simultaneously, making it a true multi-frame, blind deconvolution method. The new method was tested on simulated and experimental imagery. The full procedure was implemented on a workstation with a low-end graphics processing unit, and timing tests were evaluated to estimate execution times.

Editorial Commentary: Are We Really Ready to Talk About Sports After Osteochondral Allograft Transplantation?

When it comes to return to high-level sports participation, articular cartilage surgical treatment outcomes were historically abysmal, whereas osteochondral allografts have allowed return to sport at rates as high as 88%. However, although osteochondral allograft transplantation effectively reconstructs the damaged articular surface in affected knees, the grafts themselves do nothing to re-establish normal joint homeostasis, resulting in high reoperation rates. Return to sport should require recovery of nearly normal motion and strength, as well as magnetic resonance imaging showing intact cartilage, bony incorporation, and no effusion. These milestones typically occur at 6 months. Persistent joint inflammation and reactivity remain a vexing issue, and long-term durability is of significant concern. In the future, a goal could be to develop biological therapies that could modulate the joint inflammation and catabolism associated with articular cartilage injury.

Satisfaction with dental care among patients who receive invasive or non-invasive treatment for non-cavitated early dental caries: findings from one region of the National Dental PBRN.

BACKGROUND: The objectives were to: (1) quantify patient satisfaction with treatment for early dental caries overall, and according to whether or not (2a) the patient received invasive treatment; (2b) was high-risk for dental caries, and had dental insurance; and (3) encourage practitioners to begin using non-invasive approaches to early caries management. METHODS: Ten practitioners recorded patient, lesion, and treatment information about non-cavitated early caries lesions. Information on 276 consecutive patients with complete data was included, who received either non-invasive (no dental restoration) or invasive (dental restoration) treatment. Patients completed a patient satisfaction questionnaire and were classified as dissatisfied if they did not "agree" or "strongly agree" with any of 14 satisfaction items. RESULTS: Patients had a mean (± SD) age of 41.8 (±15.8) years, 64% were female and 88% were white. Twenty-five percent (n = 68) were dissatisfied in at least one of the 14 satisfaction items. Satisfaction levels did not significantly vary by patient's gender, race, caries risk category, or affected tooth surface location. Overall, 11% (28 of 276) received invasive treatment; satisfaction did not differ between patients who had invasive or non-invasive treatment. Seven patients received invasive treatment at their request even though that was not what their practitioner recommended; 5 out of 6 were satisfied with their treatment nonetheless. CONCLUSIONS: About one-fourth of patients treated for non-cavitated early caries were dissatisfied with at least some aspect of their dental care experience. Satisfaction of patients who received invasive treatment did not differ from those who received non-invasive treatment.

Repair or Replacement of Restorations: A Prospective cohort study by dentists in The National Dental Practice-Based Research Network.

BACKGROUND: A prospective cohort study that included dentists in The National Dental Practice-Based Research Network was conducted to quantify 12-month failures of restorations that were repaired or replaced at baseline. The study tested the hypothesis that no significant differences exist in failure percentages between repaired and replaced restorations after 12 months. It also tested the hypothesis that certain dentist, patient, and restoration characteristics are significantly associated with the incidence of restoration failure. METHODS: Dentists recorded data for 50 or more consecutive defective restorations. The restorations that were either - repaired or replaced were recalled after 12 months and characterized for developing defects. RESULTS: Dentists (N = 195) recorded data on 5,889 restorations; 378 restorations required additional treatment (74 repaired, 171 replaced, 84 teeth received endodontic treatment, and 49 were extracted). Multivariable logistic regression analysis indicated that additional treatment was more likely to occur if the original restoration had been repaired (7%) compared with replaced (5%) (odds ratio [OR], 1.6; P < .001; 95% confidence interval [CI], 1.2-2.1), if a molar was restored (7%) compared with premolars or anterior teeth (5% and 6%, respectively) (OR, 1.4; P = .010; 95% CI, 1.1-1.7), and if the primary reason was a fracture (8%) compared with other reasons (6%) (OR, 1.3; P = .033; 95% CI, 1.1-1.6). CONCLUSIONS: An additional treatment was more likely to occur within the first year if the original restoration had been repaired (7%) compared with being replaced (5%). However, repaired restorations were less likely to need an aggressive treatment (replacement, endodontic treatment, or extraction) than replaced restorations. PRACTICAL IMPLICATIONS: One year after repair or replacement of a defective restoration, the failure rate was low. However, repaired restorations were less likely to need an aggressive treatment than replaced restorations.

Reliability of pain intensity clamping using response-dependent thermal stimulation in healthy volunteers.

BACKGROUND: Pain intensity clamping uses the REsponse-Dependent Stimulation (REDSTIM) methodology to automatically adjust stimulus intensity to maintain a desired pain rating set-point which is continuously monitored from a subject's real-time pain ratings. REDSTIM blinds subjects regarding the pain intensity set-point, supporting its use for assessing intervention efficacy. By maintaining the pain intensity at a constant level, a potential decrease in pain sensitivity can be detected by an increase in thermode temperature (unknown to the subject) and not by pain ratings alone. Further, previously described sensitizing and desensitizing trends within REDSTIM provide a novel insight into human pain mechanisms overcoming limitations of conventional testing methods. The purpose of the present study was to assess the test-retest reliability of pain intensity clamping using REDSTIM during three separate sessions. METHODS: We used a method for testing changes in pain sensitivity of human subjects (REDSTIM) where the stimulus temperature is modulated to clamp pain intensity near a desired set-point. Temperature serves as the response variable and is used to infer pain sensitivity. Several measures were analyzed for reliability including average temperature and area under the curve (AUC). Intraclass correlation coefficients were calculated for each measure at pain rating set-points of 20/100 and 35/100. RESULTS: Sixteen healthy individuals (mean age = 21.6 ± 3.9) participated in three experiments two days apart at both pain rating set-points. Most reliability coefficients were in the moderate to substantial range (r's = 0.79 to 0.94) except for the negative AUC (r = 0.52), but only at the 20/100 pain rating set-point. CONCLUSIONS: The present study supports the test-retest reliability of pain intensity clamping using the REDSTIM methodology while providing a novel tool to examine human pain modulatory mechanisms and overcoming common shortcomings of conventional quantitative sensory testing methods.

Determinants of First-Time Cancer Examinations in a Rural Community: A Mechanism for Behavior Change.

OBJECTIVES: After conducting a media campaign focusing on the importance of oral and pharyngeal cancer (OPC) examinations, we assessed mechanisms of behavior change among individuals receiving an OPC examination for the first time. METHODS: We used data from 2 waves of telephone surveys of individuals residing in 36 rural census tracts in northern Florida (n = 806). The second survey occurred after our media intervention. We developed media messages and modes of message delivery with community members via focus groups and intercept interviews. We performed a mediation analysis to examine behavior change mechanisms. RESULTS: Greater exposure to media messages corresponded with heightened concern about OPC. Heightened concern, in turn, predicted receipt of a first-time OPC examination, but only among men. CONCLUSIONS: We extended earlier studies by measuring an outcome behavior (receipt of an OPC examination) and demonstrating that the putative mechanism of action (concern about the disease) explained the link between a media intervention and engaging in the target behavior. Improving the quality of media campaigns by engaging community stakeholders in selecting messages and delivery methods is an effective strategy in building public health interventions aimed at changing behaviors.

Dentists' use of caries risk assessment and individualized caries prevention for their adult patients: Findings from The Dental Practice-Based Research Network.

OBJECTIVES: Few studies have examined dentists' subjective ratings of importance of caries risk factors or tested whether dentists use this information in treatment planning. This study tested several hypotheses related to caries risk assessment (CRA) and individualized caries prevention (ICP). METHODS: Data were collected as part of a questionnaire entitled 'Assessment of Caries Diagnosis and Caries Treatment' completed by 547 practitioners who belong to The Dental Practice-Based Research Network (DPBRN), a consortium of participating practices and dental organizations. RESULTS: Sixty-nine percent of DPBRN dentists perform CRA on their patients. Recently graduated dentists, dentists with busier practices, and those who believe a dentist can predict future caries were the most likely to use CRA. The association between CRA and individualized prevention was weaker than expected (r = 0.21). Dentists who perform CRA provide ICP to 57% of their patients, compared with 42% for dentists who do not perform CRA. Based on their responses to radiographic and clinical scenarios in the questionnaire, dentists who use CRA appear to use this information in restorative decisions. CONCLUSION: A substantial percentage of DPBRN dentists do not perform CRA, and there is not a strong linkage between its use and use of individualized preventive regimens for adult patients. More progress in the implementation of current scientific evidence in this area is warranted.

The Decision to Repair or Replace a Defective Restoration is Affected by Who Placed the Original Restoration: Findings from the National Dental PBRN.

OBJECTIVES: To evaluate how restoration characteristics are associated with the decision to repair or replace an existing restoration. The following hypotheses were studied: dentists who placed the original restoration are more likely to repair instead of replace restorations (H1) that are in molar teeth; (H2) that are in the upper arch; (H3) that have amalgam restorative material; (H4) if a fracture is not the primary reason for the defect; and (H5) when the restoration comprises more than one surface. METHODS: This cross-sectional study used a consecutive patient/restoration recruitment design. 194 dentists members of a dental practice-based research network recorded data on restorations in permanent teeth that needed repair or replacement. RESULTS: For 6,623 of the 8,770 defective restorations in 6,643 patients, the treatment was provided by the dentist who had not placed the original restoration (75%). The 2-way interaction revealed that dentists who had placed the original restoration often chose to repair when the defective restoration was in a molar, relative to premolar or anterior teeth (OR = 2.2, p <.001); and chose to replace when the restoration had amalgam (OR = 0.5, p < .001), and when it was a fracture compared to another reason (OR = 0.8, p = 001). CONCLUSION: Most dentists are not conservative when they revisit a restoration that they originally placed regardless of type of failure, number of surfaces or material used. However, dentists who had placed the original restoration were significantly more likely to repair it when the defective restoration was in a molar tooth. CLINICAL SIGNIFICANCE: Most dentists who placed the original restoration were prone to replace it, however if the defective restoration was located in a molar tooth they would consider repairing it.

Health literacy: a pathway to better oral health.

OBJECTIVES: We examined whether health literacy was associated with self-rated oral health status and whether the relationship was mediated by patient-dentist communication and dental care patterns. METHODS: We tested a path model with data collected from 2 waves of telephone surveys (baseline, 2009-2010; follow-up, 2011) of individuals residing in 36 rural census tracts in northern Florida (final sample size n = 1799). RESULTS: Higher levels of health literacy were associated with better self-rated oral health status (B = 0.091; P < .001). In addition, higher levels of health literacy were associated with better patient-dentist communication, which in turn corresponded with patterns of regular dental care and better self-rated oral health (B = 0.003; P = .01). CONCLUSIONS: Our study showed that, beyond the often-reported effects of gender, race, education, financial status, and access to dental care, it is also important to consider the influence of health literacy and quality of patient-dentist communication on oral health status. Improved patient-dentist communication is needed as an initial step in improving the population's oral health.

Sex differences in the incidence of severe pain events following surgery: a review of 333,000 pain scores.

OBJECTIVE/BACKGROUND: Prior work has not addressed sex differences in the incidence of severe postoperative pain episodes. The goal of this study was to examine sex differences in clinical postoperative pain scores across an array of surgical procedures using direct comparisons of numeric rating scale pain scores as well as using the incidence of severe pain events (SPEs). DESIGN/SETTING: Retrospective cohort study of over 300,000 clinical pain score observations recorded from adult patients undergoing nonambulatory surgery at a tertiary care academic medical center over a 1-year period. METHODS/PATIENTS: To test the hypothesis that the number of SPE on postoperative day (POD) 1 differed by sex after controlling for procedure, we calculated Cochran-Mantel-Haenszel statistics of sex by count of SPE, controlling for type of surgery. ASSESSMENT TOOLS/OUTCOMES: Pain scores were collected from clinical nursing records where they were documented using the numeric rating scale. RESULTS: In female patients, 10,989 (25.09%) of 43,806 POD 1 pain scores were considered SPE compared with 10,786 (22.45%) of 48,055 POD 1 pain scores in male patients. This produced an overall odds ratio of 1.16 (99% confidence interval 1.11-1.20) for females vs males to report an SPE for a pain score on POD 1. Estimates of the odds that a given pain observation represents an SPE for female vs male patients after controlling for type of surgery yielded an odds ratio of 1.14 (99% confidence interval, 1.10-1.19). CONCLUSION: Female patients experience greater mean pain scores, as well as a higher incidence of SPE, on POD 1 for a variety of surgical procedures.

Isometric exercise as a test of pain modulation: effects of experimental pain test, psychological variables, and sex.

OBJECTIVE: Little is known regarding whether exercise-induced hypoalgesia (EIH) produced by isometric exercise is influenced by psychological factors or systematically varies across multiple experimental psychophysical pain tests. Thus, this study sought to determine the influence of experimental pain test, psychological factors, and sex on the hypoalgesic response of submaximal isometric exercise. METHODS: Healthy young males (N = 12) and females (N = 15) completed one training and two testing sessions consisting of quiet rest (control condition) or a 3-minute isometric handgrip performed at 25% of maximum voluntary contraction. Pain testing was conducted on both forearms prior to and following exercise and quiet rest. The pain tests included: pressure pain thresholds (PPT), suprathreshold pressure pain test, static prolonged heat test, and temporal summation of heat pain. Participants completed the Pain Catastrophizing Scale during the training session and the State-Trait Anxiety Inventory-State version prior to each session. The data were analyzed with mixed model analyses of variance, partial Pearson correlations, and hierarchical regression analyses. RESULTS: Isometric exercise increased PPTs for men and women, reduced pain perception during static prolonged heat stimuli for women, and reduced temporal summation of pain for men and women. Greater pain catastrophizing was associated with smaller reductions in temporal summation following isometric exercise. CONCLUSIONS: These findings demonstrate that the hypoalgesic response to submaximal isometric exercise is partially a function of sex and experimental pain test. Furthermore, the relationship between EIH and pain catastrophizing was psychophysical pain test specific, with greater pain catastrophizing predicting diminished EIH only during the temporal summation of pain trials.

Restorative material and other tooth-specific variables associated with the decision to repair or replace defective restorations: findings from the dental PBRN.

OBJECTIVES: Using data from dentists participating in The Dental Practice-Based Research Network (DPBRN), the study had 2 main objectives: (1) to identify and quantify the types of restorative materials in the existing failed restorations; and (2) to identify and quantify the materials used to repair or replace those failed restorations. METHODS: This cross-sectional study used a consecutive patient/restoration recruitment design. Practitioner-investigators recorded data on consecutive restorations in permanent teeth that needed repair or replacement. Data included the primary reason for repair or replacement, tooth surface(s) involved, restorative materials used, and patient demographics. RESULTS: Data for 9,875 restorations were collected from 7,502 patients in 197 practices for which 75% of restorations were replaced and 25% repaired. Most of the restorations that were either repaired or replaced were amalgam (56%) for which most (56%) of the material used was direct tooth-colored. The restorative material was 5 times more likely to be changed when the original restoration was amalgam (OR = 5.2, p < .001). The likelihood of changing an amalgam restoration differed as a function of the tooth type (OR = 3.0, p < .001), arch (OR = 6.6, p < .001); and number of surfaces in the original restoration (OR = 12.2, p < .001). CONCLUSION: The probability of changing from amalgam to another restorative material differed with several characteristics of the original restoration. The change was most likely to take place when (1) the treatment was a replacement; (2) the tooth was not a molar; (3) the tooth was in the maxillary arch; and (4) the original restoration involved a single surface.

Increasing screening intentions for oral and pharyngeal cancer.

BACKGROUND: Oral and pharyngeal cancer is a serious health threat that goes unnoticed by most people. Increasing screenings for oral and pharyngeal cancer is essential to achieving early detection when the disease is most treatable. PURPOSE: We tested the effectiveness of a media campaign designed to increase intentions to seek an oral and pharyngeal cancer screening. We further examined whether concern and knowledge of oral and pharyngeal cancer mediated screening intentions. METHODS: Participants in the intervention condition received messages on posters, handheld fans, pamphlets, and magnets displayed on the sides of cars or trucks. Participants in the intervention and comparison conditions (N = 1,790) were surveyed prior to and after the intervention. RESULTS: Intervention participants reported greater intentions to seek free oral and pharyngeal cancer screenings. Concern about oral and pharyngeal cancer partially mediated the effect whereas knowledge did not. CONCLUSIONS: Our media campaign successfully increased screening intentions by heightening concerns.

Relationships between the intensity and duration of Peltier heat stimulation and pain magnitude.

Ramp-and-hold heat stimulation with a Peltier thermode is a standard procedure for quantitative sensory testing of human pain sensitivity. Because myelinated and unmyelinated nociceptive afferents respond preferentially to changing and steady temperatures, respectively, ramp-and-hold heat stimulation could assess processing of input from A-delta nociceptors early and C nociceptors late during prolonged thermal stimulation. In order to evaluate the progression from dynamic change to a steady temperature during prolonged Peltier stimulation, recordings of temperatures at the probe-skin interface were obtained. First, recordings of temperature during contact-and-hold stimulation (solenoid powered delivery of a preheated thermode to the skin) provided an evaluation of heat dissipation from the beginning of stimulation, uncontaminated by ramping. The heat-sink effect lasted up to 8 s and accounted in part for a slow increase in pain intensity for stimulus durations of 1-16 s and stimulus intensities of 43-59 °C. Recordings during longer periods of stimulation showed that feedback-controlled Peltier stimulation generated oscillations in temperature that were tracked for up to 75 s by subjects' continuous ratings of pain. During 120-s trials, sensitization of pain was observed over 45 s after the oscillations subsided. Thus, long-duration stimulation can be utilized to evaluate sensitization, presumably of C nociception, when not disrupted by oscillations in thermode temperature (e.g., those inherent to feedback control of Peltier stimulation). In contrast, sensitization was not observed during 130.5 s of stimulation with alternately increasing and decreasing temperatures that repeatedly activated A-delta nociceptors.

Experimental pain phenotype profiles in a racially and ethnically diverse sample of healthy adults.

OBJECTIVE: To examine patterns of interindividual variability in experimental pain responses emerging from multiple experimental pain measures in a racially/ethnically diverse sample of healthy adults and to examine the association between the derived phenotype profiles with demographic, psychological, and health-related measures. METHODS: Two hundred and ninety-one participants underwent heat, cold, pressure, and ischemic pain assessments, and completed several psychological and health-related assessments. The experimental pain measures were subjected to a principal component analysis and factor scores were used to compute Pain Sensitivity Index scores. The scores were subsequently submitted to a cluster analysis to identify patterns of pain sensitivity across experimental pain modalities. RESULTS: The sample was equally composed of non-Hispanic whites, African Americans, and Hispanic whites. Sensitivity scores were computed for heat pain, pressure pain, cold pain, ischemic pain, and temporal summation of heat pain. Five distinct clusters were characterized by high heat pain sensitivity, low ischemic pain sensitivity, low cold pain sensitivity, low pressure pain sensitivity, and high temporal summation. Cluster membership was significantly different by sex as well as somatic reactivity and catastrophizing, although cluster differences were most pronounced between the heat pain-sensitive individuals vs the cold pain-insensitive individuals. CONCLUSIONS: Our findings highlight the importance of phenotyping individuals to account for interindividual differences in pain responses. Our findings also replicate previously reported pain phenotypes, which are not solely related to demographic, psychosocial, or health-related factors in our healthy participants. Future studies designed to elucidate the biological underpinnings of pain sensitivity profiles would be of substantial value.

The burden of chronic diseases in a rural North Florida sample.

BACKGROUND: The degree of health disparities present in rural communities is of growing concern and is considered "urgent" since rural residents lag behind their urban counterparts in health status. Understanding the prevalence and type of chronic diseases in rural communities is often difficult since Americans living in rural areas are reportedly less likely to have access to quality health care, although there are some exceptions. Data suggest that rural residents are more likely to engage in higher levels of behavioral and health risk-taking than urban residents, and newer evidence suggests that there are differences in health risk behavior within rural subgroups. The objective of this report is to characterize the prevalence of four major and costly chronic diseases (diabetes, cardiovascular disease, cancer, and arthritis) and putative risk factors including depressive symptoms within an understudied rural region of the United States. These four chronic conditions remain among the most common and preventable of health problems across the United States. METHODS: Using survey data (N = 2526), logistic regression models were used to assess the association of the outcome and risk factors adjusting for age, gender, and race. RESULTS: Key findings are (1) Lower financial security was associated with higher prevalence of cardiovascular disease, arthritis, and diabetes, but not cancer. (2) Higher levels of depressive symptoms were associated with higher prevalence of cardiovascular disease, arthritis, and diabetes. (3) Former or current smoking was associated with higher prevalence of cardiovascular disease and cancer. (4) Blacks reported higher prevalence of diabetes than Whites; Black women were more likely to report diabetes than all other groups; prevalence of diabetes was greater among women with lower education than among women with higher education. (5) Overall, the prevalence of diabetes and arthritis was higher than that reported by Florida and national data. CONCLUSIONS: The findings presented in this paper are derived from one of only a few studies examining patterns of chronic disease among residents of both a rural and lower income geographic region. Overall, the prevalence of these conditions compared to the state and nation as a whole is elevated and calls for increased attention and tailored public health interventions.

Reduction of conditioned pain modulation in humans by naltrexone: an exploratory study of the effects of pain catastrophizing.

The current study tested the hypothesis that conditioned pain modulation is mediated by the release of endogenous opioids with a placebo-controlled (sugar pill) study of naltrexone (50 mg) in 33 healthy volunteers over two counter-balanced sessions. Pain modulation consisted of rating of heat pain (palm) during concurrent cold water immersion (foot). Compared to baseline heat pain ratings, concurrent foot immersion lowered pain intensity ratings, which suggests an inhibitory effect, was reduced with naltrexone, suggesting at least partial dependence of inhibition on endogenous opioids. An exploratory analysis revealed that individual differences in catastrophizing moderated the effects of naltrexone; endogenous opioid blockade abolished modulation in subjects lower in catastrophizing while modulation was unaffected by naltrexone among high catastrophizers. The results suggest a role of endogenous opioids in endogenous analgesia, but hint that multiple systems might contribute to conditioned pain modulation, and that these systems might be differentially activated as a function of individual differences in responses to pain.

Methods used by dental practice-based research network dentists to diagnose dental caries.

OBJECTIVES: To (1) identify the methods that dentists in The Dental Practice-based Research Network (DPBRN) use to diagnose dental caries; (2) quantify their frequency of use, and (3) test the hypothesis that certain dentist and dental practice characteristics are significantly associated with their use. METHODS: A questionnaire about methods used for caries diagnosis was sent to DPBRN dentists who reported doing some restorative dentistry; 522 dentists participated. Questions included the use of dental radiographs, the dental explorer, laser fluorescence, air-drying and fiber-optic devices and magnification as used when diagnosing primary, secondary/recurrent or non-specific caries lesions. Variations on the frequency of their use were tested using multivariate analysis and Bonferroni tests. RESULTS: Overall, the dental explorer was the instrument most commonly used to detect primary occlusal caries and caries at the margins of existing restorations. In contrast, laser fluorescence was rarely used to help diagnose occlusal primary caries. For proximal caries, radiographs were used to help diagnose 75%-100% of lesions by 96% of the DPBRN dentists. Dentists who use radiographs most often to assess proximal surfaces of posterior teeth were significantly more likely to also report providing a higher percentage of patients with individualized caries prevention (p = .040) and seeing a higher percentage of pediatric patients (p = .001). CONCLUSION: The use of specific diagnostic methods varied substantially. The dental explorer and radiographs are still the most commonly used diagnostic methods.