Effect of temperature and air pressure on the incidence of Bell's palsy in Hangzhou: a distributed lag non-linear analysis.

The etiology of Bell's palsy (BP) is currently unknown, and the findings from previous studies examining the association between seasonal or meteorological factors and BP have been inconsistent. This research aims to clarify this relationship by analyzing a larger dataset and employing appropriate statistical methods. Data from 5387 patients with BP treated at Zhejiang Provincial Hospital of Traditional Chinese Medicine in Hangzhou, Zhejiang Province, from May 1, 2018, to June 30, 2023, was gathered. We assessed the temporal distribution of meteorological factors and the incidence of BP across seasons and months. A distributed lag non-linear model was used to further investigate the lagged and overall effects of temperature and air pressure on the onset of BP. The temporal distribution of BP incidence revealed the highest average number of cases occurring in December and the lowest in June. A correlation existed between BP episodes and temperature or air pressure. The model revealed a higher relative risk during periods of low temperature and high air pressure, characterized by a time lag effect. This correlation was notably more pronounced in female patients and individuals in the young and middle-aged groups. Our findings suggest that exposure to low temperatures and high air pressure constitute risk factors for BP development.

Microparticle-induced vascular injury in mice following decompression is inhibited by hyperbaric oxygen: effects on microparticles and interleukin-1ß.

Hyperbaric oxygen (HBO2) became a mainstay for treating decompression sickness (DCS) because bubbles are associated with the disorder. Inflammatory processes including production of circulating microparticles (MPs) have now been shown to occur with DCS, leading to questions regarding pathophysiology and the role for HBO2. We investigated effects of HBO2 on mice exposed to 790 kPa air pressure for 2 h, which triggers elevations of MPs ladened with interleukin (IL)-1ß that cause diffuse vascular injuries. Exposure to 283 kPa O2 (HBO2) inhibited MP elevations at 2 h postdecompression by 50% when applied either prophylactically or as treatment after decompression, and the MP number remained suppressed for 13 h in the prophylactic group. Particle content of IL-1ß at 2 h postdecompression was 139.3 ± 16.2 [means ± SE; n = 11, P < 0.05) pg/million MPs vs. 8.2 ± 1.0 ( n = 15) in control mice, whereas it was 31.5 ± 6.1 ( n = 6, not significant vs. control (NS)] in mice exposed to HBO2 prophylactically, and 16.6 ± 6.3 ( n = 7, NS) when HBO2 was administered postdecompression. IL-1ß content in MPs was similar in HBO2-exposed mice at 13 h postdecompression. HBO2 also inhibited decompression-associated neutrophil activation and diffuse vascular leak. Immunoprecipitation studies demonstrated that HBO2 inhibits high-pressure-mediated neutrophil nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 inflammasome oligomerization. Furthermore, MPs isolated from decompressed mice cause vascular injuries when injected into naïve mice, but if decompressed mice were exposed to HBO2 before MP harvest, vascular injuries were inhibited. We conclude that HBO2 impedes high-pressure/decompression-mediated inflammatory events by inhibiting inflammasome formation and IL-1ß production. NEW & NOTEWORTHY High pressure/decompression causes vascular damage because it stimulates production of microparticles that contain high concentrations of interleukin-1ß, and hyperbaric oxygen can prevent injuries.

Microencapsulation of anthocyanin extract from purple rice bran using modified rice starch and its effect on rice dough rheology.

The investigation aims to microencapsulate anthocyanin extract from purple rice bran with modified glutinous rice starch to provide stable anthocyanin powder. The modified glutinous rice starch was used as wall material where anthocyanin extract was a core material for microencapsulation. The microencapsulation was carried out in a spray dryer, and the process was optimized using a rotatable central composite design. The effect of independent parameters, viz., starch concentration, inlet air temperature, and atomizer pressure, on the dependent parameters, such as encapsulation efficiency, anthocyanin content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, true density and water activity were investigated. The optimum values of the spray drying process parameters were 6.01% of starch concentration, 168.78 °C inlet air temperature and 4.96 MPa atomizer pressure. The physical characteristics of spray-dried powders were investigated in term of water activity (0.51), solubility (51.83%), bulk density (1.404 g/cm3), porosity (0.20), and diameter (6.44 µm) and the Hausner ratio (1.020). The thermal, crystallinity and surface morphology of the microencapsulated particles were also comprehensively studied using DSC, XRD, FTIR, and SEM. The storage stability of microencapsulated anthocyanin showed more stability at 4 °C than at 25 °C for 90 days. The microencapsulated particles also have an effect on the steady-shear rheology of the rice dough.

Tension pneumoperitoneum during pneumatic reduction of pediatric intussusception: case report

This paper presents a case report of tension pneumoperitoneum that occurred in a 4-month-old girl with intussusception during pneumatic reduction. Tension pneumoperitoneum is a rare but life threatening complication in air pressure enema that is commonly used to turn the intussuscepted bowel to its original position. The incidence of a simple pneumoperitoneum due to a bowel perforation associated with attempted pneumatic reduction for intussusception is as high as 4%. The simple pneumoperitoneum changed rapidly to tension pneumoperitoneum and immediate needle decompression was life-saving in this case. Similar to a tension pneumothorax, the diagnosis is clinical and management should not be delayed awaiting other confirmatory tests. The emergency physician must recognize this rare complication of pneumatic reduction and promptly treat the ensuing tension pneumoperitoneum after bowel perforation with immediate needle decompression as a part of the initial resuscitation.

Wideband Acoustic Immittance: Normative Study and Test-Retest Reliability of Tympanometric Measurements in Adults.

PURPOSE: The purpose of this study was to present normative data of tympanometric measurements of wideband acoustic immittance and to characterize wideband tympanograms. METHOD: Data were collected in 84 young adults with strictly defined normal hearing and middle ear status. Energy absorbance (EA) was measured using clicks for 1/12-octave frequencies (0.236 to 8 kHz), with the ear canal air pressure systematically varied (+200 to -300 daPa). In 40 ears, 7 consecutive trials and a trial of clinical 226-Hz acoustic admittance (Ya) tympanometry followed. A cavity test was also conducted. RESULTS: From the wideband EA tympanogram, several EA spectrums and EA tympanograms were derived. Descriptive statistics were performed, and population parameters were estimated. The immediate test-retest reliability was excellent. Effects of ear canal air pressure on EA were examined comprehensively. Differences in EA between tympanometric and ambient-pressure measurements were significant. Single-frequency EA tympanograms exemplified for half-octave frequencies were contrasted. The bandpass EA tympanogram, 0.236- and 1-kHz EA and Ya tympanograms, and 226-Hz Ya tympanogram were compared in 9 variables. CONCLUSIONS: This study established a database of wideband tympanograms in healthy adults. The data analyses will promote our understanding of the middle ear transfer function. These data will serve as a reference for further studies in clinical populations.

Effect of hyperbaric oxygen conditions on the ordering of interfacial water.

Hyperbaric oxygen (HBO2) conditions are applied clinically to treat diverse conditions. There is a lack of a unifying consensus as to how HBO2 acts effectively against a broad range of medical conditions, and numerous differing biological explanations have been offered. The possibility of a mechanism dependent on the extensive ordering of interfacial water has not yet been investigated. We examined the hypothesis that zones of ordered water, dubbed "exclusion zones" or "EZ," are expanded under hyperbaric oxygen conditions. Specifically, we tested whether there are significant quantitative differences in EZ size at steady state under high-pressure and/or high-oxygen conditions, compared to normal atmospheric conditions. Oxygen concentration and mechanical pressure were examined separately and in combination. Statistically significant increases in EZ size were seen at elevated air pressures and at high oxygen concentrations. These experimental results suggest the possibility of an ordered water-mediated mechanism of action for hyperbaric oxygen therapy.

Procedures for ambient-pressure and tympanometric tests of aural acoustic reflectance and admittance in human infants and adults.

Procedures are described to measure acoustic reflectance and admittance in human adult and infant ears at frequencies from 0.2 to 8 kHz. Transfer functions were measured at ambient pressure in the ear canal, and as down- or up-swept tympanograms. Acoustically estimated ear-canal area was used to calculate ear reflectance, which was parameterized by absorbance and group delay over all frequencies (and pressures), with substantial data reduction for tympanograms. Admittance measured at the probe tip in adults was transformed into an equivalent admittance at the eardrum using a transmission-line model for an ear canal with specified area and ear-canal length. Ear-canal length was estimated from group delay around the frequency above 2 kHz of minimum absorbance. Illustrative measurements in ears with normal function are described for an adult, and two infants at 1 month of age with normal hearing and a conductive hearing loss. The sensitivity of this equivalent eardrum admittance was calculated for varying estimates of area and length. Infant-ear patterns of absorbance peaks aligned in frequency with dips in group delay were explained by a model of resonant canal-wall mobility. Procedures will be applied in a large study of wideband clinical diagnosis and monitoring of middle-ear and cochlear function.

Pressure induced lung injury in a novel in vitro model of the alveolar interface: protective effect of dexamethasone.

PURPOSE: The lungs of infants born with congenital diaphragmatic hernia suffer from immaturity as well as the short and long term consequences of ventilator-induced lung injury, including chronic lung disease. Antenatal and postnatal steroids are among current strategies promoted to treat premature lungs and limit long term morbidity. Although studied in whole-animal models, insight into ventilator-induced injury at the alveolar-capillary interface as well as the benefits of steroids, remains limited. The present study utilizes a multi-fluidic in vitro model of the alveolar-interface to analyze membrane disruption from compressive aerodynamic forces in dexamethasone-treated cultures. METHODS: Human alveolar epithelial cell lines, H441 and A549, were cultured in a custom-built chamber under constant aerodynamic shear followed by introduction of pressure stimuli with and without dexamethasone (0.1µM). On-chip bioelectrical measurements were noted to track changes to the cellular surface and live-dead assay to ascertain cellular viability. RESULTS: Pressure-exposed alveolar cultures demonstrated a significant drop in TEER that was less prominent with an underlying extracellular-matrix coating. Addition of dexamethasone resulted in increased alveolar layer integrity demonstrated by higher TEER values. Furthermore, dexamethasone-treated cells exhibited faster recovery, and the effects of pressure appeared to be mitigated in both cell types. CONCLUSION: Using a novel in vitro model of the alveolus, we demonstrate a dose-response relationship between pressure application and loss of alveolar layer integrity. This effect appears to be alleviated by dexamethasone and matrix sub-coating.

Effect of training on inspiratory load compensation in weaned and unweaned mechanically ventilated ICU patients.

BACKGROUND: While inspiratory muscle weakness is common in prolonged mechanical ventilation, inspiratory muscle strength training (IMST) can facilitate strengthening and ventilator weaning. However, the inspiratory load compensation (ILC) responses to threshold loads are not well characterized in patients. We retrospectively compared ILC responses according to the clinical outcomes of IMST (ie, maximum inspiratory pressure [PImax], weaning outcome), in difficult-to-wean ICU patients. METHODS: Sixteen tracheostomized subjects (10 weaned, 6 unweaned) from a previous clinical trial underwent IMST 5 days/week, at the highest tolerated load, in conjunction with daily, progressive spontaneous breathing trials. PImax and ILC with a 10 cm H2O load were compared in the subjects before and after IMST. Changes in ILC performance were further characterized (5, 10, 15 cm H2O loads) in the trained subjects who weaned. RESULTS: Demographics, respiratory mechanics, and initial PImax (52 ± 26 cm H2O vs 42 ± 13 cm H2O) did not significantly differ between the groups. Upon enrollment, PImax significantly correlated with flow ILC responses with the 10 cm H2O load (r = 0.64, P = .008). After IMST, PImax significantly increased in the entire sample (P = .03). Both before and after IMST, subjects who weaned generated greater flow and volume ILC than subjects who failed to wean. Additionally, ILC flow, tidal volume, and duty cycle increased upon ventilator weaning, at loads of 5, 10, and 15 cm H2O. CONCLUSIONS: Flow ILC at a threshold load of 10 cm H2O in ventilated, tracheostomized subjects positively correlated with PImax. Although PImax improved in both groups, the flow and volume ILC responses of the weaned subjects were more robust, both before and after IMST. The results suggest that ILC response is different in weaned and unweaned subjects, reflecting dynamic inspiratory muscular efforts that could be influential in weaning.

[Studies on baicalin ethylcellulose microspheres for intranasal administration].

In this study, solvent evaporation method was used to preparing baicalin ethylcellulose microspheres for intranasal administration. The prepared microspheres were round with certain rough surface. The average drug loading and entrapment efficiency was (33. 31 ± 0. 045)% , (63. 34 ± 0. 11)% , respectively. As the characteristic crystalline peaks of baicalin were observed in the microspheres sample, the result of X-ray diffractometric analysis indicated that the baicalin was present in crystalline form after its entrapment in ethylcellulose matrix. By investigating the thermogram of microspheres sample, it was found that endothermic peak of baicalin was shifted from 211. 8 °C to 244. 2 °C and associated with the first broad endothermic peak of ethylcellulose. This could confirm that baicalin was loaded into ethylcellulose, nor simply physical mixture. The powder flowability test exhibited that the specific energy of microspheres was 3. 57 mJ . g-1 and the pressure drop was 2. 22 mBar when air kept the speed of 2 mm . s-1 through the powder bed with the force was 15 kPa. The consequence of the baicalin in vitro released from microspheres showed that the pure baicalin sample displayed faster (90%) release than microspheres sample (75%) in 7 h. Fitting model for release curve before 7 h, the results showed that the pure baicalin sample and the microsphere sample accorded with first order model (R2 = 0. 990 4) and Riger-Peppas model(R2 = 0. 961 2), respectively. Ex vivo rabbit nasal mucosa permeability experiment revealed that the value of cumulative release rate per unit area of the microsphere sample was 1. 56 times that of the pure baicalin sample. This provided the foundation for the in vivo pharmacokinetic study.

Autonomic changes in young smokers: acute effects of inspiratory exercise.

PURPOSE: One of the most important consequences of smoking is the development of cardiovascular diseases. However, little is known about the early consequences of smoking and the acute effects of a single inspiratory muscle exercise session (IME). We evaluated the acute effects of an IME on cardiac parameters of young smokers. METHODS: Twelve nonsmokers (C) and fifteen smokers [S; 2.08 (1.0-3.2) pack-years] underwent an acute IME. We evaluated blood pressure (BP) and lactate, and we recorded RR interval for posterior analysis of heart rate variability (HRV), before and after IME. RESULTS: At baseline, systolic BP and HRV parameters in time and frequency domains were changed in S group in comparison with the C. Following IME, S group reduced systolic BP (-8 %), low frequency band (LF) (-21.4 %), LF/high frequency (HF) (-57 %), as well as increased RR variance (+105 %) and HF band. CONCLUSIONS: Our findings indicate that a single session of inspiratory muscle exercise was able to both reduce systolic BP and improve parasympathetic and sympathetic modulations in young smokers. The results of the current study highlight the importance of furthering research on this area to better elucidate the acute and chronic effects of inspiratory muscle training on early cardiovascular and pulmonary changes of cigarette smoking.

Potential for hypobaric storage as a phytosanitary treatment: mortality of Rhagoletis pomonella (Diptera: Tephritidae) in apples and effects on fruit quality.

The efficacy of low-oxygen atmospheres using low pressure, referred to as hypobaric conditions, to kill egg and third-instar Rhagoletis pomonella (Walsh) in apples was investigated. Infested apples were exposed to 3.33 and 6.67 kPa in glass jars at 25 and 30 degrees C for times ranging from 3 to 120 h. Probit analyses and lethal dose ratio tests were performed to determine differences in lethal time values. Eggs were more tolerant of low pressure compared with third-instar R. pomonella. Mortality of eggs and larvae increased with increase in time of exposure to low pressure and temperature. Lower pressures increased percent mortality of eggs, but these values were not significantly different at the pressures tested in this investigation. The LT99 for R. pomonella eggs at 3.33 kPa was 105.98 and 51.46 h, respectively, at 25 and 30 degrees C, which was a significant effect of the higher temperature on egg mortality. Investigation into consumer acceptance of low-pressure-treated apples was done with 'Red Delicious' and 'Golden Delicious'. Apples exposed to 3.33 kPa at 25 and 30 degrees C for 3 and 5 d were stored at 1 degrees C for 2 wk and presented to a sensory panel for evaluation. The panelists rated treated apples with untreated controls for external and internal appearance and taste. Golden Delicious apples were unaffected for all three sensory factors across both temperatures and exposure times. Although taste was unaffected for Red Delicious, the internal and external appearances deteriorated. Use of low pressure for disinfestation and preservation of apples is a potential nonchemical alternative to chemical fumigants such as methyl bromide and phosphine.

Different reactions of human nasal and Eustachian tube mucosa after hyperbaric oxygen exposure: a pilot study.

Impairment of Eustachian tube function has been observed after hyperbaric oxygen treatment as well as after diving on oxygen used as breathing gas. The aim of the present study was to evaluate the influence of hyperbaric oxygen exposure on Eustachian tube ventilatory function and airflow characteristics of the nose. Six police task force divers performing two consecutive dives within a regular training schedule on oxygen were examined. Middle ear impedance, and nasal airflow velocities before and after diving as well as on the morning after the dive day were measured. Middle ear impedance decreased overnight in comparison to pre-dive values (P = 0.027) as well as compared to the value after the first dive (P = 0.032). Rhinoflowmetry did not reveal any changes of nasal airflow velocities related to the dives. Furthermore, no association between middle ear impedance and nasal airflow velocities was found. An impairment of Eustachian tube ventilatory function was obtained after hyperbaric oxygen exposure during dives employing oxygen as breathing gas. This impairment, however, was not associated with altered airflow characteristics of divers' noses. Thus, it seems unlikely that hyperbaric oxygen exerts an effect on the nasal mucosa similar to that on the Eustachian tube mucosa.

Huperzine A ameliorates cognitive deficits and oxidative stress in the hippocampus of rats exposed to acute hypobaric hypoxia.

Acute exposure to high altitudes can cause neurological dysfunction due to decreased oxygen availability to the brain. In this study, the protective effects of Huperzine A on cognitive deficits along with oxidative and apoptotic damage, due to acute hypobaric hypoxia, were investigated in male Sprague-Dawley rats. Rats were exposed to simulated hypobaric hypoxia at 6,000 m in a specially fabricated animal decompression chamber while receiving daily Huperzine A orally at the dose of 0.05 or 0.1 mg/kg body weight. After exposure to hypobaric hypoxia for 5 days, rats were trained in a Morris Water Maze for 5 consecutive days. Subsequent trials revealed Huperzine A supplementation at a dose of 0.1 mg/kg body weight restored spatial memory significantly, as evident from decreased escape latency and path length to reach the hidden platform, and the increase in number of times of crossing the former platform location and time spent in the former platform quadrant. In addition, after exposure to hypobaric hypoxia, animals were sacrificed and biomarkers of oxidative damage, such as reactive oxygen species, lipid peroxidation, lactate dehydrogenase activity, reduced glutathione, oxidized glutathione and superoxide dismutase were studied in the hippocampus. Expression levels of pro-apoptotic proteins (Bax, caspase-3) and anti-apoptotic protein (Bcl-2) of hippocampal tissues were evaluated by Western blotting. There was a significant increase in oxidative stress along with increased expression of apoptotic proteins in hypoxia exposed rats, which was significantly improved by oral Huperzine A at 0.1 mg/kg body weight. These results suggest that supplementation with Huperzine A improves cognitive deficits, reduces oxidative stress and inhibits the apoptotic cascade induced by acute hypobaric hypoxia.

Improving the efficiency of an Er:YAG laser on enamel and dentin.

OBJECTIVE: To evaluate the influence of air pressure, water flow rate, and pulse frequency on the removal speed of enamel and dentin as well as on their surface morphology. METHOD AND MATERIALS: Twenty-four bovine incisors were horizontally cut in slices. Each sample was mounted on an experimental assembly, allowing precise orientation. Eighteen cavities were prepared, nine in enamel and nine in dentin. Specific parameters for frequency, water flow rate, and air pressure were applied for each experimental group. Three groups were randomly formed according to the air pressure settings. Cavity depth was measured using a digital micrometer gauge, and surface morphology was checked by means of scanning electron microscopy. Data was analyzed with ANOVA and Duncan post hoc test. RESULTS: Irradiation at 25 Hz for enamel and 30 Hz for dentin provided the best ablation rates within this study, but efficiency decreased if the frequency was raised further. Greater tissue ablation was found with water flow rate set to low and dropped with higher values. Air pressure was found to have an interaction with the other settings, since ablation rates varied with different air pressure values. CONCLUSION: Fine-tuning of all parameters to get a good ablation rate with minimum surface damage seems to be key in achieving optimal efficiency for cavity preparation with an Er:YAG laser.

Pneumatic reduction of intussusception in children at Korle Bu Teaching Hospital: an initial experience.

BACKGROUND: Intussusception is a common abdominal emergency in children which necessitates prompt diagnosis and management. Nonsurgical methods of managing this condition are rapidly gaining popularity with fluoroscopic-guided pneumatic reduction being one of such methods that has been used with great success in many countries. We present our initial experience with fluoroscopic-guided pneumatic reduction of intussusception at Korle Bu Teaching Hospital which is also the first time the technique has been used in Ghana. MATERIALS AND METHODS: A total of 18 children were enrolled in the study between August 2007 and February 2008 at Korle Bu Teaching Hospital, Accra, Ghana. Patients were given air enema under fluoroscopic-guidance using locally assembled equipment. The intraluminal pressure was monitored with a pressure gauge and was not permitted to go above 120 mmHg. A total of three attempts of 3 min each were allowed. RESULTS: There were 12 males and 6 females. The average age of the patients was 8.3 months (SD= 3 months). Twelve (67%) of the cases were reduced successfully while 6 (33%) failed to reduce. A majority of those that did not reduced had symptoms for at least 2 days. Bowel perforation occurred in three (16.7%) cases. CONCLUSION: Pneumatic reduction of intussusception is a cost-effective and rapid method of management of intussusception. It however has limitations like high reported rate of bowel perforation and limited ability to identify lead points. The benefits however seem to outweigh these challenges, such as fluoroscopic-guided pneumatic reduction has a very high success rate. Fluoroscopic guided pneumatic reduction should be considered as one of the primary modes of reduction in Ghana and other neighbouring countries that are yet to practice it.

Effects of air-polishing powders on color stability of composite resins

OBJECTIVES: The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. MATERIAL AND METHODS: Thirty cylindrical specimens (15×2 mm) were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C) and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder). A standard air-polishing unit (ProSmile Handly) was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic) for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300). Color differences (∆E*) between the 2 color measurements (baseline and after 24 h storage) were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (p<0.05). RESULTS: According to the 2-way ANOVA results, composite resin restorative materials, air-polishing powders, and their interaction were statistically significant (p<0.05) For Aelite Aesthetic Enemal, Filtek Z250, Grandio, CeramX Mono, and Quixfil composite resin restorative materials, no significant difference was observed between Group-PS and Group-CP (p>.05) and these groups demonstrated the highest ∆E* values. For Filtek Silorane and IntenS, the highest ∆E* values were observed in Group-PS. The lowest ∆E* values for all composite resin groups were observed in Group-C. When comparing the 7 composite resin restorative materials, Aelite Aesthetic Enemal demonstrated significantly less ∆E* values than the other composite resins tested. The highest ∆E* values were observed in Quixfil. CONCLUSION: Except for Quixfil, all control groups of composite resins that were polished Sof-Lex exhibited clinically acceptable ∆E values (<3.7). Air-polishing applications increased the color change for all composite resin restorative materials tested. Composite restorations may require re-polishing after air-polishing.

Effects of air-polishing powders on color stability of composite resins.

OBJECTIVES: The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. MATERIAL AND METHODS: Thirty cylindrical specimens (15×2 mm) were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C) and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder). A standard air-polishing unit (ProSmile Handly) was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic) for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300). Color differences (∆E*) between the 2 color measurements (baseline and after 24 h storage) were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (p<0.05). RESULTS: According to the 2-way ANOVA results, composite resin restorative materials, air-polishing powders, and their interaction were statistically significant (p<0.05) For Aelite Aesthetic Enemal, Filtek Z250, Grandio, CeramX Mono, and Quixfil composite resin restorative materials, no significant difference was observed between Group-PS and Group-CP (p>.05) and these groups demonstrated the highest ∆E* values. For Filtek Silorane and IntenS, the highest ∆E* values were observed in Group-PS. The lowest ∆E* values for all composite resin groups were observed in Group-C. When comparing the 7 composite resin restorative materials, Aelite Aesthetic Enemal demonstrated significantly less ∆E* values than the other composite resins tested. The highest ∆E* values were observed in Quixfil. CONCLUSION: Except for Quixfil, all control groups of composite resins that were polished Sof-Lex exhibited clinically acceptable ∆E values (<3.7). Air-polishing applications increased the color change for all composite resin restorative materials tested. Composite restorations may require re-polishing after air-polishing.

Relationships among standard and wideband measures of middle ear function and distortion product otoacoustic emissions.

BACKGROUND: The overall goal of the current study was to examine the relationships among uncompensated admittance (Ya) at ambient pressure extracted from tympanograms, energy reflectance (ER) measures at ambient pressure from wideband acoustic transfer functions (WATF), and distortion product otoacoustic emissions (DPOAEs). If WATF measures of Ya are comparable to tympanometric measures of Ya at ambient pressure, it would be further evidence that the two systems provide comparable information at ambient pressure. Such a relationship could be used as a cross-check or validation for WATF measures and support the use of WATFs in lieu of tympanograms in some applications. Finally, if WATF measures of Ya and/or ER at DPOAE stimulus frequencies can account for some of the variability observed in DPOAE levels and/or signal-to-noise ratios (SNRs) in ears with normal hearing, the relationships could be used to improve hearing screening procedures. PURPOSE: The hypotheses were as follows: (1) measures of Ya at ambient pressure are significantly correlated as measured with tympanometric and WATF procedures and (2) measures of Ya and ER at DPOAE stimulus frequencies are significantly correlated with DPOAE level and SNR. RESEARCH DESIGN: Repeated measures in human adults. STUDY SAMPLE: Forty ears of 20 adults with normal hearing and middle ear function were included in the final sample. DATA COLLECTION AND ANALYSIS: Tympanograms were obtained using probe frequencies of 226, 678, and 1000 Hz; WATFs were obtained using a click probe, and DPOAEs were elicited with f2's of 1000, 2000, and 4000 Hz. A repeated measures analysis of variance (RM-ANOVA) was completed to identify significant differences between ears and among probe frequencies for Ya measured at ambient pressure from the Tympstar and for Ya measured at the three closest frequencies on the WATFs. Lines were fit to the comparison of Ya from the Tympstar and WATF, and percent variance accounted for (r2) was calculated. Ya and ER were extracted at all stimulus frequencies that were used to elicit DPOAEs and were compared to DPOAE levels and SNRs. RM-ANOVAs were completed to identify any significant differences in DPOAE level and SNR between ears and among f2 conditions. Lines were fit to the comparison of Ya and ER measures at f1 and f2 with the DPOAE levels and SNRs. The relationship between behavioral air conduction threshold at each f2 and DPOAE level (and SNR) was examined with regression analysis. RESULTS: Ya was significantly correlated between the tympanometric and WATF measures at all three probe-tone frequencies. Ya and ER at f1 and f2 were significantly correlated with DPOAE level for f2 = 4000 Hz. CONCLUSIONS: The implications are as follows: (1) WATFs, which can be obtained with the same probe microphone system as DPOAEs, could be used as a supplement to tympanometry in a diagnostic test battery, and the relationship between Ya measured on the two systems could be used for verification, and (2) Ya and ER measures from WATFs at both DPOAE stimulus frequencies account for some of the variability observed in DPOAE levels at f2 = 4000 Hz in normal ears.