Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Turbinates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources

Nasal turbinate resection for relief of nasal obstruction.

Surgical correction of mechanical nasal airway obstruction is commonly attempted by means of septoplasty or submucous resection. In spite of these procedures, patients continue to present postoperatively with inadequate nasal airflow due to hypertrophied turbinates. Partial resection of turbinate mucosa, submucous turbinate resection, electrocautery and outfracture of turbinates provide additional improvement but are incomplete procedures. Total inferior turbinectomies have been performed on 40 patients over the past 5 years; 29 of these patients have been followed from 2 to 60 months postoperatively by clinical examination and by formal questionnaire. Twenty-five patients described a marked improvement of their nasal breathing, 3 had mild improvement, and 1 had no improvement at all. Only 1 patient, 1 year postoperatively, described excessive dryness, 2 described mild dryness, 3 described excessive secretions and none complained of foul smell or pain postoperatively. All patients had patent airways by clinical examination by at least 2 otolaryngologists. The inferior turbinates play a role in humidification and temperature regulation of inspired air. The removal of them, however, does not seem to be fraught with the morbidity which has heretofore been attributed to this procedure.

Adolescent↗

Radiofrequency volumetric tissue reduction (RFVTR) of inferior turbinates: a new method in the treatment of chronic nasal obstruction.

Twenty-two Caucasians (16 male and 6 female) with chronic bilateral nasal obstruction due to hypertrophic inferior turbinates were followed up over a three-month period. They were assessed by clinical examination, as active anterior rhinometry, and acoustic rhinometry before and after topical decongestion, preoperatively and three months after surgery. All patients were treated by application of radiofrequency-volumetric-tissue reduction (RFVTR, or somnoplasty) to both inferior turbinates. Initial postoperative edematous response disappeared during the first week after RFVTR. Three months postoperatively 20 of 22 patients (91%) reported subjective improvement of nasal patency. The average cross-sectional area for both sides of the nasal cavity (measured at the head of the inferior turbinate (C-Notch) before decongestion) increased in 15 of 22 patients (68.2%). This means a significant improvement from 1.24 to 1.49 cm2 for both sides of the nasal cavity (p = 0.0054). We conclude that RFVTR can safely reduce turbinate volume in a precise manner in patients with nasal obstruction due to hypertrophic inferior turbinates.

Adolescent↗

Swiftlase assisted CO2 laser ablation in the treatment of nasal obstruction due to hypertrophy of the inferior turbinates.

Hypertrophy of the inferior turbinates are the major cause of nasal obstruction. CO2 lasers have been used to reduce the size of the inferior turbinates over the last 20 years. However, the many techniques of delivery of the laser show that there is no one standard method reducing the size of the turbinates. We now describe how the laser can be applied directly to the turbinates using a handpiece with a special nasal tip, thus overcoming the disadvantages delivery via arthroscopic devices, microscopes and fibers. This technique is further enhanced by coupling it with Swiftlase which swirls the focused beam in a 3 mm spot thus ablating tissue more quickly. This procedure is done under local anaesthesia. The ablation of the anterior third of the inferior turbinates effectively overcomes nasal obstruction. This new method was compared to the more traditional submucus diathermy. 22 patients were subjected to laser treatment whilst 20 patients were subjected to diathermy. The outcome was evaluated subjectively by the patients themselves at 2 weeks, 3 months and 6 months. At the end of the study, the laser group reported a more significantly improved nasal airway (91% against 75%) and decreased rhinorrhea (72.7% against 35%) when compared to the diathermy group.

Adolescent↗

Middle turbinate resection: impact on outcomes in endoscopic sinus surgery.

There is considerable controversy concerning the advisability and efficacy of middle turbinate resection in endoscopic sinus surgery. Some have reported that it causes an increase in the incidence of frontal sinusitis, while others have found no such association. Surprisingly, in a 35-year review of turbinate surgery literature, Clement and White did not find a single prospective study of turbinate surgery. In this article, we briefly report our prospective study of middle turbinate resection during endoscopic sinus surgery. Our findings lead us to believe that middle turbinate resection has no deleterious effects on the results of endoscopic sinus surgery.

Endoscopy↗

Enlargement of the bone component in different parts of compensatorily hypertrophied inferior turbinate.

BACKGROUND: To evaluate the unilateral compensatorily hypertrophied inferior turbinate (CHIT) by computed tomography (CT) and determine the enlargement of the bone component in different parts of the CHIT. METHODS: Patients were studied in three groups: those with a straight or nearly straight septum (n = 143), with mild deviation (n = 42), and with moderate to severe deviation (n = 99). The cross sectional area (CSA) of the inferior turbinate (IT) bone and the whole turbinate were measured at anterior, middle, and posterior thirds of the IT in coronal sections. The ratio of CSA of the IT bone on two sides of the septum (interturbinate ratio) and the ratio of the CSA of the overall turbinate to the IT bone (intraturbinate ratio) were calculated. RESULTS: The interturbinate ratio of the bony turbinate CSA for the severe deviation group was significantly higher compared with other groups in anterior and middle segments (p < 0.0001). The intraturbinate ratio was highest in the posterior segment and lowest in the middle segments in compensatorily hypertrophied sides for all groups (p < 0.001). CONCLUSION: Skeletal enlargement is prominent in anterior and middle thirds of CHIT in patients with pronounced septal deviation.

Adolescent↗

Numerical simulation of intranasal air flow and temperature after resection of the turbinates.

BACKGROUND: Radical surgical resection of the turbinates leads to a reduced intranasal air conditioning. The aim of this study was to determine the effect of turbinate resection on intranasal heating and airflow patterns using a numerical simulation. METHODS: A bilateral model of the human nose with resection of the turbinates on one side based on a CT-scan was reconstructed. A numerical simulation applying the computational fluid dynamics (CFD) solver Fluent 6.1.22 was performed displaying inspiratory intranasal air temperature and airflow patterns. RESULTS: Due to resection of the turbinates the airflow pattern is disturbed resulting in a spacious vortex throughout the entire nasal cavity. Hence, contact between air and surrounding nasal wall is less intense. Consequently, intranasal heating of the inspired air is relevantly reduced. CONCLUSIONS: Surgical resection of the turbinates leads to a disturbed intranasal air conditioning. The presented numerical simulation demonstrates the close relation between airflow patterns and heating.

Body Temperature↗

[The middle turbinate as the cause of sinusal pathology].

The middle turbinate and its anatomical variations (concha bullosa and paradoxically bent middle turbinate) may be the site of different pathologies due to the alteration of the sinus function at the key area of the osteomeatal complex. In the present work we study 4 cases of concha bullosa and 4 cases of paradoxically bent middle turbinates, associated to recurrent sinusitis and/or headaches, which underwent endoscopic surgery. Improvement was achieved in all recurrent circumscribed sinusitis. One of the patients with bilateral paradoxically bent middle turbinate had an associated pansinusitis, and he only improved in his right side. An aspergilloma was found inside one of the conchae bullosae. Headaches improved in all the cases analyzed. Anatomic variations may be the cause of recurrent sinusal pathology or isolated headaches and it should be noted that, in correctly selected groups, a dramatic improvement can be achieved with a minor surgical procedure on the middle turbinate or ethmoidal infundibulum.

Adolescent↗

Consequences of prolonged inhalation of ozone on F344/N rats: collaborative studies. Part XII: Atrophy of bone in nasal turbinates.

As part of the National Toxicology Program/Health Effects Institute collaborative study of the health effects of prolonged ozone exposure, it was observed that rats chronically exposed to ozone had marked histopathologic changes in the upper respiratory tract, including atrophy of the nasal turbinates. The principal objective of the present study was to morphometrically assess the severity of the ozone-induced changes in the bony tissue of the maxilloturbinates in these chronically exposed rats. Male and female F344/N rats were exposed to 0, 0.12, 0.5, or 1.0 part per million (ppm) ozone, 6 hours/day, 5 days/week for 20 or 24 months. Rats were killed one week after the end of the exposure, and nasal tissues were processed for light and electron microscopy. Using image analysis and standard morphometric techniques, the amounts of bone, surface epithelium, and lamina propria comprising the maxilloturbinates were estimated by measuring the cross-sectional area of each tissue compartment at a defined location in the proximal nasal passage. Both male and female rats had significant morphologic and morphometric changes in the maxilloturbinates after prolonged exposures to 0.5 or 1.0 ppm ozone, but not to 0.12 ppm ozone. Ozone-exposed rats had significant reductions in the cross-sectional area of turbinate bone, reflecting the loss of bone in the maxilloturbinate after prolonged exposure. This ozone-induced bony atrophy was more severe in male than in female rats. Using electron microscopy, numerous bone-resorption sites were identified on the outer, periosteal, surface of the turbinate bone in ozone-exposed animals. Rats with bony atrophy also had a conspicuous influx and mixed inflammatory cells into the lamina propria surrounding the turbinate bone. In addition, ozone exposures caused reductions in the area of lamina propria, due to blood vessel constriction, and increases the in the area of the surface epithelium, due to hyperplasia and metaplasia. The results of the present tudy demonstrated that prolonged exposure of rats to ozone can cause marked loss of turbinate bone. The severity of this ozone-induced bony atrophy in rats is dependent on both concentration and gender.

Administration, Inhalation↗

CO2 laser surgery of hypertrophied inferior turbinates.

The inferior turbinates are responsible for nasal obstruction in patients with allergic and vasomotor rhinitis. Until today there is no satisfactory means of treating hypertrophied turbinates. One hundred and eighty-four patients with nasal obstruction due to hypertrophied inferior turbinates were treated with the CO2 laser using the microscope and a micromanipulator. A few laser spots (1 W, 1 s, laser power density: 2,038 W/cm2) were applied to the head of the turbinate. After a few days a positive effect was present. One hundred and twelve patients were followed for over 2 years. Six months after laser surgery, 87.5% had excellent or good results. After one year, 82.1% of the patients were satisfied, and after 2 years 80.4% were satisfied. The procedure involves little bleeding, no pain and can be done under local anaesthesia in an outpatient setting. Less post-operative wound care is necessary. Therefore, the CO2 laser surgical technique can be considered as an effective method in the treatment of hyperthrophied turbinates.

Adult↗

Pre- and postoperative imaging analysis for frontal sinus disease following conservative partial middle turbinate resection.

The prudence of partial or complete middle turbinate resection during endoscopic sinus surgery (ESS) is controversial. The greatest concern regarding partial resection relates to the effect on the frontal recess and the development of frontal sinus disease. The purpose of this study was to radiographically evaluate the frontal sinus in patients who had undergone ESS with partial conservative middle turbinate resection. We reviewed the charts and operative records from 195 consecutive cases of ESS performed by a single surgeon (JFB) over a two-year period. Thirty-three of 117 patients who had undergone ESS with conservative partial middle turbinate resection without frontal recess exploration agreed to return for magnetic resonance imaging (MRI) of their sinuses. The preoperative computed tomography (CT) scans and postoperative MR images were reviewed and graded (1-3) by a single neuroradiologist. Significant frontal sinus disease (grades 2 and 3) was seen in 15 of 52 sides preoperatively (29%), and in 14 sides postoperatively (27%). During the postoperative MRI studies, only six frontal sinus sides demonstrated minimal mucosal thickening (grade 1) which had not been apparent on preoperative CT. This radiographic analysis suggests that conservative partial middle turbinate resection during ESS does not adversely affect the frontal sinus. We believe that the surgical technique employed when resecting the middle turbinate, and the avoidance of unnecessary dissection in the recess are both important factors in preventing the development of frontal sinus disease following ESS.

Adult↗

Large band spectral analysis and harmful risks of dental turbines.

Previous studies have attributed harmful effects to ultrasonic frequencies and recently many have addressed the problem of early deafness among dentists caused by high-speed air turbines. In this study, we measured the spectra of the sounds generated by high-speed air turbines, ranging from audible to ultrasonic frequencies (0-70 kHz). The hypothesis advanced is that the ultrasound spectrum of high-speed air turbines reaches amplitudes that may be noxious. We performed continuous analyses of the spectra of three bands of turbines (n = 17). Measurements of frontal incidence were made using a Bruel & Kjaer microphone and sonometer. For spectral analysis we used the autoregressive parametric method. Using Akaike's criteria the model weights were fixed at 12. The method used in the present work led to an accuracy in the results of 10(-2) kHz within the same brand of turbine. Results show, in terms of frequencies, the presence of four main peaks: 5.6 kHz +/- 0.73 in the audible range, and 20.1 kHz +/- 2.16, 35.7 kHz +/- 2.56 and 46.5 kHz +/- 0.71 in the ultrasonic range. In a normalized spectrum, the amplitude of the ultrasonic component reaches 115 dBspl for 46.5 kHz and is 76% greater than that of the audible component. Such values, both in terms of frequencies and amplitude, reach levels which may provoke short- or long-term negative physiological disturbances and hearing-damage risk. Further research should be directed to determine to what extent they might induce noxious effects for the dental team.

Analysis of Variance↗

Effects of sounds generated by a dental turbine and a stream on regional cerebral blood flow and cardiovascular responses.

Effects of sound generated by a dental turbine and a small stream (murmur) and the effects of no sound (null, control) on heart rate, systolic and diastolic blood pressure, and hemodynamic changes (oxygenated, deoxygenated, and total hemoglobin concentrations) in the frontal cortex were measured in 18 young volunteers. Questionnaires completed by the volunteers were also evaluated. Near-infrared spectroscopy and the Finapres technique were employed to measure hemodynamic and vascular responses, respectively. The subjects assessed the murmur, null, and turbine sounds as "pleasant," "natural," and "unpleasant," respectively. Blood pressures changed in response to the murmur, null, and turbine sound stimuli as expected: lower than the control level, unchanged, and higher than the control level, respectively. Mean blood pressure values tended to increase gradually over the recording time even during the null sound stimulation, possibly because of the recording environment. Oxygenated hemoglobin concentrations decreased drastically in response to the dental turbine sound, while deoxygenated hemoglobin concentrations remained unchanged and thus total hemoglobin concentrations decreased (due to the decreased oxygenated hemoglobin concentrations). Hemodynamic responses to the murmuring sound and the null sound were slight or unchanged, respectively. Surprisingly, heart rate measurements remained fairly stable in response to the stimulatory noises. In conclusion, we demonstrate here that sound generated by a dental turbine may affect cerebral blood flow and metabolism as well as autonomic responses.

Acoustic Stimulation↗

Flow and free running speed characterization of dental air turbine handpieces.

OBJECTIVES: Dental air turbine handpieces have been widely used in clinical dentistry for over 30 years, yet little work has been reported on their performance. A few studies have been concerned with measurement of speed (i.e. rotation rate), torque and power performance of these devices, but neither investigations of functional relationships between controlling variables nor theory dealing specifically with this class of turbine have been reported. This has hindered the development of satisfactory methods of handpiece specification and of testing dental rotary cutting tools. It was the intention of the present work to remedy that deficiency. METHODS: Measurements of pressure, temperature, gas flow rate and rotation rate were made with improved accuracy and precision for 14 ball bearing turbine handpieces on several gases. Functional relationships between gas properties, supply pressure, flow rate, turbine design factors and free running speed were identified and equations describing these aspects of behaviour of this class of turbine developed. RESULTS: The rotor radius, through peripheral Mach number, was found to be a major determinant of speed performance. In addition, gas flow was found to be an important limiting factor through the effect of choke. CONCLUSIONS: Each dental handpiece can be treated as a simple orifice of a characteristic cross-sectional area. Free running speed can be explained in terms of gas properties and pressure, with allowance for a design-specific performance coefficient.

Air↗

Prevention of microbial contamination of the dental unit caused by suction into the turbine drive air lines.

OBJECTIVE: To determine whether a specially designed antisuction device can prevent the bacterial contamination of the drive air lines of the dental turbine that is caused by suction when the turbine is stopped. STUDY DESIGN: A dental unit with and without the antisuction device and three different types of sterilized handpieces were used in the tests. Each turbine was operated in air, then submerged into a bacterial suspension of E. coli and enterococci for 3 seconds, removed, and stopped. This procedure was repeated 10 times. Possible bacterial contamination of the drive air lines was examined by submersing the head of a sterilized handpiece with the turbine running into a nutrient broth for 30 seconds. The broth was incubated at 35 degrees C up to 2 days. RESULTS: After use of the conventional dental unit, bacterial growth of drive air lines was found in 10 of 150 broth samples. After the installation of the antisuction device no bacterial growth was found in any of the 138 samples. The difference in the contamination frequencies is statistically significant (p = 0.011, Fisher's two-sided exact test). CONCLUSIONS: The drive air lines of the turbine in the dental unit may become contaminated despite the sterilization of handpieces. The antisuction device installed into the dental unit was found to prevent the contamination. With the exception of possibly immunocompromised patients, the transmission of microbes by exhaust air may be too small to cause infections. However, transmission of oral material between patients should be prevented in dental practice.

Air↗

Measurements of cardiac output of an isolated heart using a specially designed turbine.

Cardiac output is one of the important parameters used in evaluation of heart function. A turbine which works on mechanical principles was designed. It is also suitable for cardiac output measurements on isolated pig hearts in cases where some other equipment is not, like on doppler effect based transducers. The basic principle of measuring liquid flow through a turbine is based on measurement of the time that elapses when the rotor rotates by one degree. For this purpose, the rotor is fitted with transparent foil with a ring of 360 short black lines printed close to its circumference. Two infrared light-emitting diodes are mounted on one side of the foil and two photo-transistors, used as sensors of the transmitted infrared light, are mounted on the other. Voltage-regulated output ranging from 0 to +/- 2048 V at one revolution per second gives 500 mV at the output (changeable by programming), calculating time 2 ms, 1 mV resolution (11 bits), with an external power supply of 5 V. The turbine showed a linear response at a continuous saline flow up to 3000 ml min-1 at pressure loads of between 20 and 220 cm H2O. Pressure drop across the turbine depends on the volume flow and was 1 mm Hg at 100 ml min-1 and 3 mm Hg at 7000 ml min-1. A rotating movement 1.25 x 10(-4) kg m2 s-1 was calculated. The lowest volume change of a bolus of saline solution, detected by the turbine, was 1.6 ml.

Animals↗

Comparative study of influence on tensile bond strength of a composite to dentin using Er:YAG laser, air abrasion, or air turbine for preparation of cavities.

OBJECTIVES: The purpose of this study was to evaluate, in vitro, the tensile bond strength of the Single Bond (3M) adhesive system placed over dentin surfaces treated with air turbine, Er:YAG laser without contact and in focused or air abrasion. SUMMARY BACKGROUND DATA: The use of dentin adhesives is a well-established clinical routine among the dentists. However, there have been few reports comparing the influence of the Er:YAG laser, air abrasion, and air turbine on the Single Bond tensile bond strength of adhesives systems to dentin fact that could influence which tools dentists select for use in cavity preparations. METHODS: Twenty-three extracted retained human molars were used in this study. The coronal portion was divided in two parts and fixed in acrylic resin; the occlusal surface was abraded to a 2-mm width with a mechanic lathe until the dentin surface was completely exposed. The dental portions were divided into three groups of 15 each and treated with Er:YAG laser, air abrasion, or air turbine. A 3 mm hole in the center of each tooth was marked off using contact paper. Single Bond (3M) adhesive system was applied after acid phosphoric at 35% application for 15 sec over dentin surfaces. A resin composite cone was built into the delimited area to accomplish the tensile bond strength test on the EMIC universal test machine. The specimens were then evaluated by stereoscopy to determine the type of failures into the dentin-adhesive-resin composite surface. RESULTS: The tensile test was performed using the universal testing machine EMIC DL-2000 at a cross-head speed of 0.5 mm/min. The average results were: air turbine (17.52 MPa), Er:YAG laser (16.65 MPa) and air abrasion (15.83 MPa). Statistical treatment by ANOVA and Tukey's test (p < 0.01) showed no significant differences between the groups tested. The tensile bond strength test to the dentin showed no significant difference among the three groups when the Single Bond was used after the 35% phosphoric-acid conditioning. The stereoscopy showed a predominant adhesive failure in all groups. CONCLUSION: These results suggest that Single Bond tensile bond strength is the same as dentin prepared by Er:YAG laser, air abrasion, or air turbine.

Air Abrasion, Dental↗

Foundations for offshore wind turbines.

An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers.

Journal Article↗

A review of turbine blade tip heat transfer.

This paper presents a review of the publicly available knowledge base concerning turbine blade tip heat transfer, from the early fundamental research which laid the foundations of our knowledge, to current experimental and numerical studies utilizing engine-scaled blade cascades and turbine rigs. Focus is placed on high-pressure, high-temperature axial-turbine blade tips, which are prevalent in the majority of today's aircraft engines and power generating turbines. The state of our current understanding of turbine blade tip heat transfer is in the transitional phase between fundamentals supported by engine-based experience, and the ability to a priori correctly predict and efficiently design blade tips for engine service.

Journal Article↗