Training strategies of 10,074 athletes from 121 countries based on human development index in early COVID-19 lockdown.

The aim of this study was to investigate relationships between changes in training practices and human development index (HDI) levels, and identify strategies employed by athletes who consistently maintained their training quantity during the first 100 days of the COVID-19 pandemic. A total of 10,074 athletes (5290 amateur and 4787 professional athletes from 121 countries) completed an online survey between 17 May to 5 July 2020. We explored their training practices, including specific questions on training frequency, duration and quantity before and during lockdown (March-June 2020), stratified according to the human development index (HDI): low-medium, high, or very high HDI. During the COVID-19 lockdown, athletes in low-medium HDI countries focused on innovative training. Nevertheless, women and amateur athletes experienced a substantial reduction in training activity. Performance-driven athletes and athletes from higher HDI indexed countries, were likely to have more opportunities to diversify training activities during lockdowns, facilitated by the flexibility to perform training away from home. Factors such as lockdown rules, socioeconomic environment, and training education limited training diversification and approaches, particularly in low-medium and high HDI countries. Athletes (amateurs and professionals) who maintained the quantity of training during lockdown appeared to prioritize basic cardiovascular and strength training, irrespective of HDI level. Modifying training and fitness programs may help mitigate the decrease in training activities during lockdowns. Customized training prescriptions based on gender, performance, and HDI level will assist individuals to effectively perform and maintain training activities during lockdowns, or other challenging (lockdown-like) situations.

Assessment of bone density in edentulous maxillae using cone beam computed tomography (CBCT).

INTRODUCTION: In edentulous maxillae, the anterior maxilla is the region of interest for implant placement due to posterior bone resorption and sinus pneumatization. This study aimed to assess variations in bone density in different regions of the edentulous maxilla according to sex and age, using cone beam computed tomography (CBCT). MATERIALS AND METHODS: 69 CBCT from edentulous maxilla were analyzed. Six virtual implants were planned between the maxillary sinuses at incisor, canine, and premolar sites. Bone densities (in Hounsfield units HU) were recorded at six points on the neck, body, and apex of the buccal and lingual areas of each virtual implant. We used the two-sample t-test to compare male and female bone densities, and the Spearman correlation coefficient to analyze the correlation between mean bone density and age. One-way analysis of variance with post hoc pairwise t-tests was used to analyze the differences in density between three sites of the edentulous maxilla and the differences in density between three parts of the implant. The significance level was set at 5%. RESULTS: Mean bone density in males was significantly higher than in females. There was a significant correlation between mean bone density and age in females. Incisor sites showed the highest mean bone density, followed by canine and premolar sites. There was a significant decline in bone density from the neck to the apex. CONCLUSIONS: Bone density varied within and among edentulous maxillae. Bone density of the edentulous maxilla seemed to be influenced by age in women and by sex.

Competency Framework for Podiatric Medicine Training: A Validation Report Based on an Adapted E-Delphi Across Canada.

OBJECTIVES: Competency-based medical education has been introduced into many health professional curricula. Based on CanMEDs, a framework has recently been developed for podiatric medicine education in Canada. This study aimed to validate the framework through a consensus of various podiatric medicine experts across Canada. METHODS: An adapted Delphi method was used for content validation. Two structured online questionnaires were used to gather expert opinions and agreement on the roles and core competencies described in the framework previously developed. The validation consensus threshold was set at a minimum of 80% agreement. The summary of comments and suggestions was used to reformulate certain items after the research team reached a consensus. RESULTS: Out of the 51 experts invited from the Canadian Podiatric Medicine Association, 19 completed the first-round questionnaire (mean podiatric experience = 24.5 years; standard deviation 17.6). After the first round, "Podiatric Expert", "Communicator" and "Scholar" roles have been modified. After these modifications, a consensus was obtained at the second round completed by 13 experts. Overall, 95% of the experts agreed that the competency framework was relevant even if some indicators would need to be adapted to suit the requirements of each province and territory. CONCLUSION: This validated framework supports the excellence and the quality of our podiatric educational program. It also promotes the adoption of a uniform education of podiatrists in Canada and worldwide.

Cumulative pre-cooling methods do not enhance cycling performance in tropical climate.

The main objective of this study was to investigate the effect of mixed cooling techniques (combination of internal and external strategies, with and without menthol) during warm-up for a time trial in tropical climate. Seven heat-acclimatized trained male road cyclists participated in three experimental sessions consisting of 20-min cycling performances on a velodrome track in ecological hot and humid conditions (Guadeloupe, French West Indies; WBGT: 27.64±0.27°C; relative humidity: 76.43±2.19%), preceded by a standardized 30-min warm-up and the ingestion of cold menthol water (1) with a cooling vest soaked in ice water (ICE-VEST), (2) with a cooling vest soaked in ice menthol water (MEN-VEST), and (3) without a vest (NO-VEST). Cycling performance (total distance, distance traveled per 2-min block), physiological parameters (core body temperature recorded, heart rate) and perceptions (exertion, thermal comfort, thermal sensation) were assessed. No between-condition differences were found for physiological parameters, the total covered distance or the distance traveled per 2-min block. However, distance traveled per 2-min decreased with time (p = 0.03), with no difference between conditions, suggesting a variation in pace during the cycling performance trial (e.g., mean±SD: 1321±48.01m at T2; 1308±46.20m at T8, 1284±78.38m at T14, 1309±76.29m at T20). No between-condition differences were found for perception of exertion, thermal comfort and thermal sensation during the warm-up (11.83±3.34; 2.58±1.02; 4.39±0.94, respectively) and the performance (17.85±0.99; 2.70±1.25; 5.20±1.20, respectively) but the pairwise comparisons within condition revealed a significant increase of TS values from T0 (4.57±1.13) to T20 (6.00±0.58) only in NO-VEST condition (p = 0.04). The absence of modification of thermal sensation at the end of the cycling test under the mixed conditions (ICE-VEST and MEN-VEST) suggests a beneficial effect of wearing a cooling vest on thermal sensation although it had no effect on performance.

It's time to increase physical activity promotion among pregnant women in France.

BACKGROUND: The lockdown linked to COVID-19 was shown to have negative effects on healthy behaviors in the general population, prompting the implementation of adapted public health measures. However, more vulnerable populations, such as pregnant women, were not specifically taken into account. At the time of writing this study, we know little about how the COVID-19 pandemic impacted the physical activity (PA) behavior of pregnant women in France. Given the many reports in the literature about women's low level of PA throughout pregnancy and the negative effects of the COVID-19 lockdown on behaviors in the general population; however, we might assume that their sedentary behaviors increased. The current study aimed to analyze the French recommendations and PA promotion among pregnant women. MATERIALS AND METHODS: A literature search was done using PubMed for the key terms "physical activity/physical activity promotion," "pregnant women/pregnancy,", and "French population/France." All the relevant studies were included to support the argument for this narrative review. RESULTS: Efforts to promote PA for pregnant women often seem ineffective and even unrealistic, and many women become overweight or obese during pregnancy. Health professionals need evidence-based guidelines and continuous training and skills development in order to convincingly encourage women to be more active during pregnancy and the postpartum period. CONCLUSION: Health policies should strengthen PA promotion among pregnant women with detailed evidence-based guidelines on PA during postpartum.

Physical Activity Counselling Received Throughout Pregnancy and Effect on Behaviours: A Quasi-Experimental Study.

OBJECTIVES: The objective was to examine the frequency of physical activity (PA) counselling for pregnant women over the course of their pregnancies and the effect on the women's PA behaviour. METHODS: A quasi-experimental study was conducted in the maternity unit of a hospital. In total, 72 pregnant women were randomized into a control or intervention group. Counselling about PA was dispensed to the women in the intervention group throughout pregnancy by health professionals who had been sensitized to its importance and the recommendations. The women in the control group received the usual consultation content. The PA behaviour of pregnant women in the intervention group who reported receiving PA counselling was evaluated. The counselling and PA levels were evaluated by chi-square tests and repeated measures analysis of variance, respectively. RESULTS: Overall, the women received little counselling in accordance with the recommendations, although the intervention group women received this counselling more frequently (P = 0.049). All women in the intervention group who reported receiving counselling throughout pregnancy limited their decline in PA compared with those in the control group. The decline in total PA among normal-weight and overweight pregnant women was reduced in the intervention group (respectively, P = 0.043 and P = 0.044). CONCLUSION: Our intervention showed the effectiveness of counselling on PA behaviour, although the effect was observed at the end of pregnancy. Training and sensitizing for professionals should be strengthened to ensure that counselling in line with the recommendations to maintain or increase PA levels throughout pregnancy is provided.

One hour of internal precooling with cold water/menthol enhances cycling performance in a heat/wet stress environment: A pilot study.

The aim of this study was to compare precooling durations before aerobic performance in a heat/ wet stress environment. Seven heat-acclimated and trained male cyclists completed 1-hour time trials in a hot and humid environment. Before each trial, the cyclists drank (1) a neutral beverage at 23°C during the 1-hour pre-exercise resting period (Neutral), (2) an ice-slush/menthol beverage at -1°C during the last 30 min of the resting period (Pre-30), or (3) an ice-slush/menthol beverage at -1°C during the 1-hour pre-exercise resting period (Pre-60). In each condition, the cyclists drank cold water/menthol at 3°C during the exercise. Performance was significantly higher in Pre-60 than in Pre-30 and Neutral conditions (condition effect: F(2,12)=9.50, p=0.003, ηp2=0.61), with no difference between Pre-30 and Neutral. During the resting period, rectal temperature was significantly lower in Pre-60 than in Pre-30 and Neutral (condition effect: F(2,12)=4.48, p=0.035, ηp2=0.43). Thermal comfort and rating of perceived exertion were not affected by conditions, but thermal sensation was positively affected in Pre-60 during the resting period (Friedman condition effect at 40, 45 and 60 minutes: χ2=6.74; df=2; p=0.035; χ2=8.00; df=2; p=0.018; χ2=4.90; df=2; p=0.086, respectively) and exercise (Friedman condition effect at 5 and 60 minutes: χ2=6.62; df=2; p=0.037; χ2=6.50; df=2; p=0.039, respectively). This study shows that 1 hour of precooling with an ice-slush and menthol beverage (1) improved performance in a 1-hour time trial, (2) had a cumulative effect with a cold water/menthol beverage during this exercise, and (3) decreased rectal temperature during the resting period. This precooling method enhances cycling performance in a heat/wet stress environment.

Competency Framework for Podiatric Medicine Training in Canada: An Adapted Delphi Study.

Purpose: Podiatrists are generally defined as professionals with high-level skills in the prevention and management of local foot conditions that are not systemic diseases. Across countries, different academic trainings are implemented due to the specific context and practice of podiatric medicine. It is thus essential to support country-specific podiatry education for the development of highly skilled podiatrists. Therefore, we report the development of a podiatric medicine competency framework to support training in Canada. Participants and Methods: A Delphi process was conducted by 12 stakeholders (including 8 podiatry experts) from the University of Québec at Trois-Rivières which is the only university offering the degree of Doctor of Podiatric Medicine (DPM) in Canada. The developed framework is (1) based on the seven key roles of the Canadian medical education directives of specialists (CanMEDs) and, (2) closely aligned with the requirement of the College of Podiatrists of Québec which sets the standards of entry to practice in Québec. Results: The developed framework represents the state of the development process and the consensus of the podiatry experts. It reflects the expected profile of the institution's DPM graduates based on seven key roles (podiatry expert, communicator, collaborator, health advocate, leader and manager, scholar, and professional). This developed framework is an arborescence of complex skills defined in tangible indicators that characterize each expected part of a core competency. Twenty-four core competencies have been determined and divided into 84 enabling competencies and 288 observable indicators. Conclusion: This competency framework has been designed to support high-quality education and to develop podiatry. Next steps include: (1) validation of this framework by external experts, (2) development of rigorous evaluation methods and, (3) concrete actions for its implementation and assessment. This framework would help to define the scope of practice and capabilities of podiatric medicine, both in Canada and internationally.

Decrease of heart rate variability during exercise: An index of cardiorespiratory fitness.

The present study proposes to measure and quantify the heart rate variability (HRV) changes during effort as a function of the heart rate and to test the capacity of the produced indices to predict cardiorespiratory fitness measures. Therefore, the beat-to-beat cardiac time interval series of 18 adolescent athletes (15.2 ± 2.0 years) measured during maximal graded effort test were detrended using a dynamical first-order differential equation model. HRV was then calculated as the standard deviation of the detrended RR intervals (SDRR) within successive windows of one minute. The variation of this measure of HRV during exercise is properly fitted by an exponential decrease of the heart rate: the SDRR is divided by 2 every increase of heart rate of 20 beats/min. The HR increase necessary to divide by 2 the HRV is linearly inversely correlated with the maximum oxygen consumption (r = -0.60, p = 0.006), the maximal aerobic power (r = -0.62, p = 0.006), and, to a lesser extent, to the power at the ventilatory thresholds (r = -0.53, p = 0.02 and r = -0.47, p = 0.05 for the first and second threshold). It indicates that the decrease of the HRV when the heart rate increases is faster among athletes with better fitness. This analysis, based only on cardiac measurements, provides a promising tool for the study of cardiac measurements generated by portable devices.

Lingual foramina of the anterior mandible in edentulous patients: CBCT analysis and surgical risk assessment.

OBJECTIVE: The mandible has various unnamed accessory foramina, and surgery is often performed in the symphyseal area. The aim of this study was to analyze the anatomical characteristics of mandibular lingual foramina with the objective of preventing clinical complications during implant surgery on an edentulous mandible. STUDY DESIGN: A total of 100 cone beam computed tomography scans of completely edentulous patients were included in this study. For each canal, nine measurements were recorded in millimeters: seven length or height measurements and two diameter measurements. The placement of a standard implant was simulated and whether the implant passed through the canal was noted. The results were analyzed by t-test and chi-squared at a significance level of 0.05. Pearson correlation analysis was used to assess the relationship between variables. RESULTS: We identified 309 foramina: 236 medial lingual foramina and 73 lateral lingual foramina. We found no significant relationship between the number of foramina and the age of the individuals, or between diameter and the age or gender of the individuals. The mandibular canal was injured in 32.7 % of implant placement simulations. CONCLUSION: The risk of injury to neurovascular bundles is increased in edentulous patients due to vertical bone resorption.

Beneficial Effects of Motor Imagery and Self-Talk on Service Performance in Skilled Tennis Players.

This research aim to investigate the effects of motor imagery (MI), focused on the trajectory of the ball and the target area, and self-talk (motivational function) before the actual strike on the performance of the service in skilled tennis players. Thirty-three participants (6 females and 27 males, M age = 15.9 years), competing in regional to national competitions, were randomly divided into three groups: Control, MI, and MI + self-talk. They performed a pre-test (25 first service), 20 acquisition sessions (physical trial, physical trial + MI and physical trial + MI + self-talk), and a post-test similar to the pre-test, in match situations. The percentage of the first service, their speed, and the efficiency scores, evaluated by experts, were use as dependent variables and indicators of performance. While there was no difference in service speed ( p > 0.05), this study showed an improvement in the first service percentage and efficiency (all ps < 0.01) in the participants of the MI and MI + self-talk groups. Additionally, analyses revealed greater efficiency when MI was combined with self-talk compared to other conditions. It, therefore, seems advantageous for skilled tennis players to use MI and motivational self-talk before performing the first service balls.

Relationship Between Actual and Perceived Locomotor and Ball Skills Competence Among Children: A Person-Centered Approach.

This study examined whether profiles varying in actual and perceived locomotor and ball skill competencies would be identified and whether these profiles would differ in relation to children's characteristics. Participants were 127 (70 boys; 57 girls) French-speaking Canadian children (5-11 years). Actual and perceived motor competencies were, respectively, measured using the Test of Gross Motor Development - Third version and the pictorial scale of Perceived Movement Skill Competence. Latent profile analyses revealed four profiles: (1) Non-Alignment: Devaluation (children underestimated their slightly below average competencies; 17.9%); (2) Non-Alignment: Overestimation (children overestimated their slightly below average competencies; 24.7%); (3) Non-Alignment: Underestimation (children slightly underestimated their above average competencies; 24.9%); (4) Alignment: Low Competence (children displayed accurate but slightly below average competencies; 32.5%). Girls were more likely to correspond to profiles 1 and 4, older children and children more frequently involved in physical activity/sport practice were more likely to correspond to profile 3, and younger children were more likely to correspond to profile 2. These results emphasise the importance of considering the alignment between perceived and actual motor competencies. They also indicate that age and physical activity/sport practice were associated with higher competencies, whereas girls and younger children were associated with lower competencies.

Association Between Maternal Body Mass and Physical Activity Counseling During Pregnancy.

Aims: The antenatal period provides an important opportunity for giving advice on healthy lifestyle choices. However, the prevalence of maternal obesity is increasing, and women report that they do not receive counseling. We investigated the information given to pregnant women on gestational weight gain, physical activity, and nutrition during pregnancy in relation with their initial weight status, current gestational weight gain and diagnoses of either pre-pregnancy overweight/obesity or excessive gestational weight gain. Methods: Cross-sectional survey using a questionnaire. Pregnant participants (n = 141) were recruited from a midwife center. They completed a structured questionnaire on the information they received during their pregnancy and we assessed its relationship with their weight. Results: We found that many pregnant women did not receive advice about physical activity, gestational weight gain and nutrition (37.5, 53.2, and 66.2%, respectively). Women with weight problems (pre-pregnancy overweight/obesity and excessive gestational weight gain) were less targeted for counseling, although more than 80% of the women viewed receiving information on these topics as positive. Also, being informed of a weight problem was associated with a greater chance of receiving information about physical activity, gestational weight gain and nutrition (all p < 0.05). However, verbalization of the weight problems was low (14.0% of women with pre-pregnancy overweight were informed of their status). Conclusion: Health professionals should dispense more information, especially on PA and particularly for women with weight problems. Verbalization of the weight problem seems associated with more frequent transmission of information.

The Effect of an Olympic Distance Triathlon on Pulmonary Diffusing Capacity and its Recovery 24 Hours Later.

The Olympic distance triathlon includes maximal exercise bouts with transitions between the activities. This study investigated the effect of an Olympic distance triathlon (1.5-km swim, 40-km bike, 10-km run) on pulmonary diffusion capacity (DLCO). In nine male triathletes (age: 24 ± 4.7 years), we measured DLCO and calculated the DLCO to alveolar volume ratio (DLCO/VA) and performed spirometry testing before a triathlon (pre-T), 2 hours after the race (post-T), and the day following the race (post-T-24 h). DLCO was measured using the 9-s breath-holding method. We found that (1) DLCO decreased significantly between pre- and post-T values (38.52 ± 5.44 vs. 35.92 ± 6.63 ml∙min-1∙mmHg-1) (p < 0.01) and returned to baseline at post-T-24 h (38.52 ± 5.44 vs. 37.24 ± 6.76 ml∙min-1∙mmHg-1, p > 0.05); (2) DLCO/VA was similar at the pre-, post- and post-T-24 h DLCO comparisons; and (3) forced expiratory volume in the first second (FEV1) and mean forced expiratory flow during the middle half of vital capacity (FEF25-75%) significantly decreased between pre- and post-T and between pre- and post-T-24-h (p < 0.02). In conclusion, a significant reduction in DLCO and DLCO/VA 2 hours after the triathlon suggests the presence of pulmonary interstitial oedema. Both values returned to baseline 24 hours after the race, which reflects possible mild and transient pulmonary oedema with minimal physiological significance.

Neuromuscular Activity during Cycling Performance in Hot/Dry and Hot/Humid Conditions.

To determine the relationships between limiting factors and neuromuscular activity during a self-paced 20-km cycling time trial and evaluate the effect of environmental conditions on fatigue indices. METHODS: Ten endurance-trained and heat-acclimated athletes performed in three conditions (ambient temperature, relative humidity): HUMID (30 °C, 90%), DRY (35 °C, 46%) and NEUTRAL (22 °C, 55%). Voluntary muscular contractions and electromagnetic stimulations were recorded before and after the time trials to assess fatigue. The data on performance, temperature, heat storage, electromyogram, heart rate and rating of perceived exertion data were analyzed. RESULTS: Performance was impaired in DRY and HUMID compared with NEUTRAL environment (p < 0.05). The force developed by the vastus lateral muscle during stimulation of the femoral nerve remained unchanged across conditions. The percentage of integrated electromyogram activity, normalized by the value attained during the pre-trial maximal voluntary contraction, decreased significantly throughout the trial only in HUMID condition (p < 0.01). Neuromuscular activity in peripheral skeletal muscle started to fall from the 11th km in HUMID and the 15th km in DRY condition, although core temperature did not reach critical values. CONCLUSIONS: These alterations suggest that afferences from core/skin temperature regulate the central neural motor drive, reducing the active muscle recruited during prolonged exercise in the heat in order to prevent the system from hyperthermia.

Temperate Air Breathing Increases Cycling Performance in Hot and Humid Climate Environment.

Practicing physical activity in a hot and humid climate (HHC) is becoming increasingly common due to anthropogenic climate change and the growing number of international sports events held in warm countries. The aim of this study was to understand the physiological and psychological effects of breathing two air temperatures during cycling exercise in HHC. Ten male athletes performed two sessions of exercise in HHC (T°: 32.0 ± 0.5 °C, relative humidity: 78.6 ± 0.7%) during which they breathed hot air (HA, 33.2 ± 0.06 °C) or temperate air (TA, 22.6 ± 0.1 °C). Each session was composed of 30 min of pre-fatigue cycling at constant intensity, followed by a 10 min self-regulated performance. During pre-fatigue, TA induced a better feeling score and a lower rating of perceived effort (respectively, +0.9 ± 0.2, p < 0.05; 1.13 ± 0.21; p < 0.05) with no changes in physiological parameters. During performance, oxygen consumption and mechanical workload were increased by TA (respectively, +0.23 ± 0.1 L min-1, p < 0.05 and +19.2 ± 6.1 W, p < 0.01), whereas no significant differences were observed for psychological parameters. Reducing the breathed air temperature decreased the discomfort induced by HHC during exercise and increased the performance capacity during self-regulated exercise. Thus, breathed air temperature perception is linked to the hardship of training sessions and directly contributes to the performance decrease in HHC.

Face Cooling During Swimming Training in Tropical Condition.

The aim of this study was to test the effect of face cooling with cold water (1.2 ± 0.7°C) vs. face cooling with neutral water (28.0 ± 3.0°C) during high-intensity swimming training on both the core temperature (Tco) and thermal perceptions in internationally ranked long-distance swimmers (5 men's and 3 women's) during 2 randomized swimming sessions. After a standardized warm-up of 1,200 m, the athletes performed a standardized training session that consisted of 2,000 m (5 × 400 m; start every 5'15") at a best velocity then 600 m of aerobic work. Heart rate (HR) was continuously monitored during 5 × 400 m, whereas Tco, thermal comfort (TC), and thermal sensation (TS) were measured before and after each 400 m. Before and after each 400 m, the swimmers were asked to flow 200 mL of cold water (1.2°C) or neutral (22°C) water packaged in standardized bottles on their face. The swimmers were asked don't drink during exercise. The velocity was significantly different between cold water and neutral water (p < 0.004 - 71.58 m.min-1 ± 2.32 and 70.52 m.min-1 ± 1.73, respectively). The Tco was increased by ±0.5°C at race pace, under both face cooling conditions with no significant difference. No significant changes were noted in mean HR (i.e., 115 ± 9 and 114 ± 15 bpm for NW and CW, respectively). TC was higher with Cold Cooling than Neutral Cooling and TS was lower with Cold cooling compared with Neutral cooling. The changes in perceptual parameters caused by face cooling with cold water reflect the psychological impact on the physical parameters. The mean velocity was less important with face cooling whereas the heat rate and Tco were the same in the both conditions. The mechanism leading to these results seems to involve brain integration of signals from physiological and psychological sources.

Oxidative stress, inflammation, blood rheology, and microcirculation in adults with sickle cell disease: Effects of hydroxyurea treatment and impact of sickle cell syndrome.

Inflammation and oxidative stress play a key role in the pathophysiology of sickle cell disease (SCD). However, the potential influence of different sickle genotypes, or hydroxyurea (HU) treatment, on these factors remains poorly documented. The present study compared several plasma markers of inflammation and oxidative stress, as well as microvascular function, between patients with sickle SC disease (HbSC, n = 19) and patients with sickle cell anemia (HbSS) under hydroxyurea (HU) treatment (n = 16), or not (n = 13). Hemorheological parameters and levels of inflammatory (IL-6, IL-8, IFN-γ, MCP-1, MIP-1ß, TNF-α) and oxidative stress (AOPP, MDA, MPO) markers were determined. Peripheral microcirculatory cutaneous blood flow and immediate microvascular response to local heat were evaluated using laser Doppler flowmetry. Oxidative stress and inflammation were lower in HbSC patients and HbSS patients under HU therapy compared to HbSS patients not treated with HU. Blood viscosity was higher in HbSC than in HbSS patients treated with or not with HU. Vasodilation response of the cutaneous microcirculation to heat stress was higher in HbSS patients receiving HU treatment. Our results clearly established that both sickle cell genotype and HU treatment modulate inflammation and oxidative stress.

Cone beam computed tomography analysis of the edentulous mandibular symphysis.

BACKGROUND/PURPOSE: Overdenture with single symphyseal implant is one of the useful clinical approach for elderly edentulous patients. We aimed to evaluate edentulous patients with regards to the relationship between dimensions, bone characteristics, cancellous densities, and cortical thickness of the mandibular symphyseal region using cone beam computed tomography (CBCT). MATERIAL AND METHODS: We analyzed 103 CBCT from pre-implant investigations. All included patients were healthy without any disorders affecting bone metabolism. We performed 13 measurements for each patient: 9 of height, width, and thickness (mm) and 4 of density (Hounsfield Units; HU). Fisher's exact test was applied to examine the association between two categorical variables, the Pearson correlation coefficient to measure the strength of linear relationship between two quantitative variables. We used the two-sample Student's t-test to compare mean symphysis height between men and women, the paired Student's t-test to compare mean lingual and buccal cortical thickness. For all tests, the threshold of significance was fixed at 5%. RESULTS: Men and women significantly differed with regards to mean total symphysis height (p = 0.004) and the distribution of Cawood and Howell classifications (p = 0.033). Symphysis height was negatively correlated with mean density of cancellous bone (r = -0.453, p < 0.001). Mean lingual cortical thickness significantly differed from mean vestibular thickness (p < 0.001, paired Student's t-test). CONCLUSION: Present findings supported that symphyseal measurements are parameters that reflect the symphysis bone characteristics, and can guide the choice of a suitable implant design.

Influence of High-Pressure Polymerization on Mechanical Properties of Denture Base Resins.

PURPOSE: The purpose of this study was to study the influence of high-pressure (HP) polymerization on the mechanical properties of denture base PMMA resins compared with conventional thermopolymerization and PMMA discs for digital dentures. MATERIALS AND METHODS: Three groups of blocks were prepared: Probase Hot (Ivoclar Vivadent, Lichtenstein) conventionally heat polymerized at 100°C, Probase Hot heat polymerized at 100°C under HP (200 MPa) and Ivobase CAD (Ivoclar Vivadent, Lichtenstein). Samples for mechanical/physical (n = 30) and samples for viscoelastic (n = 10) characterizations were cut from the blocks. Flexural strength (σf ), elastic modulus (Ef ), hardness, density (ρ), flexural deformation at maximal flexural stress, flexural load energy (Ur ) and viscoelastic properties (E', E'', Tanδ, Tg ) were analyzed using one-way ANOVA (α = 0.05), Scheffé multiple means comparisons (α = 0.05) and Weibull statistics (for σf ). SEM images of the fractured surfaces were obtained. RESULTS: Ef , E', E'' and density of HP polymerized Probase hot were significantly higher than conventional heat polymerized Probase Hot, whereas Tg was significantly lower and σf , Tanδ, hardness, flexural deformation at maximal flexural stress, Ur were not significantly different. The highest values for σf , flexural deformation at maximal flexural stress, Ur and Weibull modulus were obtained with Ivobase CAD. CONCLUSION: HP polymerization does not significantly increase the mechanical properties of denture base resins.