[Basic studies on development of new type air turbine handpiece for dental use. Part 1. Analysis of noise from air turbine handpiece for dental use].
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Air Pressure↗
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[Development of new type plastics air turbine handpiece for dental use].
The noise generated by the metal air turbine handpiece employed in dental practice is considerable and attended with predominant high frequency components. Therefore, investigation of the noise generation mechanism and development of a silent air turbine handpiece was only a matter of course. In addition, the metal air turbine hardpiece is comparatively heavy and its production cost is high. From this point of view as well, production of a light air turbine handpiece at low cost is also desirable. In order to overcome the objections to the metal air turbine handpiece, appropriate plastics materials were employed wherever possible. In this study, the number of revolutions, noise level, frequency analysis, start pressure and weight of newly produced plastics handpieces and metal handpieces were examined and compared. The following results were obtained: 1. The number of revolutions of single-nozzle type air turbine handpieces encased in plastics housings and fitted with metal turbine rotors was higher than that of all-metal air turbine handpieces. The noise level of the former tended to be lower. 2. The number of revolutions of multi-nozzle type air turbine handpieces encased in plastics housings and fitted with turbine rotors with plastics turbine blades was almost equal to that of similar metal handpieces, with the noise level tending to be lower. 3. In the case of handpieces fitted with turbine rotors with dynamic balance, the number of revolutions was high and the noise level was low. This indicated that dynamic balance was a factor affecting the number of revolutions and noise level. 4. Narrow band sound frequency analysis of single-nozzle type air turbine handpieces showed a sharp peak at the fundamental frequency which was the same as the number of revolutions multiplied by the number of rotor turbine blades. It is thought that the noise from air turbine handpieces was aerodynamic in origin, being generated by the periodical interruption of steady air flow by rotor turbine blades. 5. The start pressure of plastics handpieces was almost equal to that of metal handpieces. 6. The weight of plastics handpieces was 20%-50% of that of metal handpieces. The present results indicate that it is possible to produce a new type of light, silent and aesthetical air turbine handpiece.
Dental Cavity Preparation↗
[Design-dependent transmission of bacteria by internal infection of dental turbines (author's transl)].
The results of the present investigation point to an up to now little recognized possibility of bacterial transmission by dental turbines, namely, the intake of spray water by reverse suction from the turbine hand piece into the cooling water system on turning off the unit. Reverse suction is provided in most modern dental turbine units to prevent after-drip and the cooling of the pre-warmed spray. As a consequence, microorganisms of the oral flora and possibly disease-producing bacteria may be carried into the cooling water system and thus be transmitted to the next patient when using the same turbine. In carefully planned experiments employing E. coli as test organisms it could be shown both in simulated manipulation in the oral cavity as well as in in vitro experiments that transmission of bacteria is possible in up to 10 ml of spray water ejected (equivalent to 10 spray water fractions of 1 ml each). In older model turbines without spray water reverse suction, bacteria were absent after ejection of no more than 6 ml of cooling water (in fractions of 1 ml each). In order to avoid transmission of bacteria in spray water of dental turbines it appears necessary to subject the turbine hand piece or the turbine head, resp., to rigorous disinfection and to allow delivery of at least 20 ml of spray water - corresponding to about 20 second's operation - before reusing the unit.
Bacterial Infections↗
Density of mucous glands in the normal adult nasal turbinates.
On 13 normal inferior and middle turbinates the mucous membrane was freed, stained by the PAS-alcian blue whole-mount method, and the mean density of glandular orifices was determined by counting in 4 mm2 fields. The median density fell in both turbinates in the anteroposterior direction, being in the inferior turbinate 8.2 glands/mm2 anteriorly, 7.9 in the middle, and 7.1 glands/mm2 posteriorly. In the middle turbinate it was 8.4 glands/mm2 anteriorly, 8.1 in the middle, and 7.3 glands/mm2 posteriorly. There were no significant differences in median density between the medial and lateral wall or between the superior and inferior half of the inferior or middle turbinate as a whole. The median total number of glands in the inferior turbinate was 9,200 with a very wide interindividual range of 6,100-12,700. In the middle turbinate the median count was 6,700 glands and the range 4,400-11,500. The pathology of the mucous glands of the nose is discussed.
Exocrine Glands↗
Turbinate osteoporosis in pigs following intranasal inoculation of purified Pasteurella toxin: histomorphometric and ultrastructural studies.
Turbinate osteoporosis, induced by intranasal inoculation of purified toxin isolated from serotype D Pasteurella multocida, was investigated in 3- to 5-week-old, caesarean-derived, colostrum-deprived, isolation-reared pigs. Marked bilateral reduction in relative volume of trabecular bone occurred in osseous cores of turbinates of toxin-treated pigs relative to control pigs on post-inoculation day (p.i.d.) 3, 6, 9, 12, and 15. The fractional resorptive surface along turbinate bone was greater in toxin-treated pigs when compared to controls on p.i.d. 3 and 6. A significant decrease in resorptive surface occurred over time in toxin-treated pigs, whereas the fractional resorptive surface was constant over time in control pigs. Osteoclasts in medullary spaces separating bony trabeculae of turbinates were abundant in toxin-treated pigs and scant in controls on p.i.d. 3, 6, and 9. Degeneration and necrosis of bone forming cells, principally osteoblasts, were progressively more extensive with time and were associated with decreased mineralization and reduced thickness of osteoid and woven bone matrix. Osteoclasts along resorptive surfaces of turbinate bone in toxin-treated pigs had more abundant, more highly vacuolated cytoplasm, a more prominent microvillous border, and a greater number of nuclei per cell than osteoclasts from control pigs on p.i.d. 3 and 6. We conclude that this Pasteurella toxin stimulates osteoclastic osteolysis and inhibits osteogenesis in turbinates by causing degeneration and death of osteoblasts.
Animals↗
Acetylcholinesterase levels in nasal turbinate congestion.
In a previous communication, one of the authors discussed prolonged congestion of the turbinates following nasal surgery. The clinical factors responsible were allergy or the traumatic effects of nasal packing on the turbinates. A study of turbinate function was done to find the factor responsible for this congestion. Biopsies of an inferior turbinate were obtained preoperatively and two weeks after surgery. The specimens were examined for the level of acetylcholinesterase by histochemical assay and were also studied by examining sections histologically. In the majority of cases, the level of acetylcholinesterase fell with the appearance of congestion and rose when the turbinates returned to normal. These results suggest a connection between turbinate congestion and levels of tissue acetylcholinesterase in the presence of inflammation or allergy.
Acetylcholinesterase↗
[Endoscopic surgery of the turbinates. Preliminary results].
Turbinate surgery has become more precise thanks to miniaturisation and improvements in optical systems, therby allowing endoscopic surgery throughout the procedure including its posterior portion. Endoscopic turbinate surgery includes surgery of the hypertrophied middle turbinate "concha bullosa" which requires diagnosis for successful treatment (septoplasty, endonasal ethmoid surgery). Endoscopy has improved inferior turbinate cauterisation which has become more complete and precise especially for the posterior portion of the turbinate. It allows the use of new techniques: the YAG laser and the CO2 laser. Endoscopy allows good control during resection of the tail of the inferior turbinate and ensures hemostasis in the event of hemorrhage occurring during this procedure.
Endoscopy↗
Turbinate perimeter ratio as an indicator of conchal atrophy for diagnosis of atrophic rhinitis in pigs.
Transverse sections of snouts from 171 cross-bred (principally Yorkshire X American Landrace) pigs were evaluated for evidence of turbinate atrophy by use of conventional (atrophic rhinitis [AR] score) and morphometric methods. Of the 171 pigs, 35 were clinically normal (AR score, 0), 65 had mild AR (AR score, 1), 41 had moderate AR (AR score, 2), and 30 had severe AR (AR score, 3). Turbinate cross-sectional area (TA) and the ratio of TA to nostril cross-sectional area, called turbinate area ratio (TAR), had the lowest correlations (r = 0.24 to 0.55) with conventional AR score. Among clinically normal pigs, TA was greater in older pigs as expected, but the TAR values also were significantly (P less than 0.0001) different between 15-week-old pigs (55 kg) and 22-week-old pigs (100 kg). Turbinate perimeter and turbinate perimeter ratio (TPR) were not influenced by pig age or source. The TPR values were closely correlated with subjective visual AR scores (r = 0.73), with AR scores derived by measuring the space between the ventral portion of the scroll and the floor of the nasal cavity (r = 0.72), and the actual size of this space in millimeters (r = 0.71). Mean TPR values for pigs assigned visual AR scores of 0, 1, 2, or 3 were 1.54, 1.25, 0.97, and 0.73, respectively. The 95% confidence intervals around these mean TPR values were discreet and did not overlap. Turbinate perimeter ratio, therefore, may be a more reliable morphometric measure of atrophic rhinitis and also provides parametric data suitable for quantitative analysis.
Animals↗
Induction of nasal turbinate atrophy in germ-free pigs, using Pasteurella multocida as well as bacterium-free crude and purified dermonecrotic toxin of P multocida.
To establish the role of the dermonecrotic toxin (DNT) of Pasteurella multocida in the cause and pathogenesis of atrophic rhinitis, germ-free pigs were inoculated with several strains of P multocida, crude DNT, or purified DNT. In some experiments, the aforementioned inocula were combined with Bordetella bronchiseptica. All DNT-producing P multocida strains induced severe turbinate atrophy. Histologic examination of the remnants of the nasal turbinates revealed intact, but undulated, ciliated epithelium and numerous osteoclasts. Inflammation was minimal or absent. A DNT-producing B bronchiseptica strain induced only mild turbinate atrophy. The lesions were characterized histologically by loss of cilia and ciliated cells and by an infiltration of predominantly mononuclear cells. Bone formation seemed impaired. Turbinate lesions were most severe in pigs infected with a combination of B bronchiseptica and a DNT-producing P multocida strain. Intranasal administration of sterile DNT-containing culture filtrate of P multocida or purified DNT of P multocida did not result in turbinate atrophy. In contrast, turbinate atrophy developed when these preparations were injected IM or when intranasal administration of DNT was preceded by inoculation of B bronchiseptica.
Animals↗
Mucociliary clearance and particle retention in the maxillary and ethmoid turbinate regions of beagle dogs.
In this study, the retention and clearance of particles instilled onto the epithelium at two sites in the nasal cavity were examined. Polystyrene microspheres (3 micron geometric diameter) were labeled with 141Ce or 85Sr and instilled simultaneously on the maxillary and ethmoid turbinates of beagle dogs. The retention and clearance patterns of the microspheres were followed for 30 d after instillation. Tissue samples, excreta content, and autoradiography of the radiolabels provided the basis for defining the fate of the microspheres or the radiolabels dissolved from the microspheres. Early nasal mucus velocity was significantly faster (p less than 0.05) from the maxillary turbinate region (2.5 +/- 0.7 mm/min, mean +/- SE) than from the ethmoid turbinate region (0.6 +/- 0.4 mm/min). Retention at both instillation sites at 30 d after instillation was approximately 0.1% of the amount initially instilled. Radioactivity was excreted primarily via the feces during the first few days. Radiolabel measured in urine and tissues other than turbinates was small (less than 0.05% of the initial burden), indicating minimal dissolution of the radiolabel from the particles. Autoradiographs of turbinate tissue revealed particles sporadically located in the epithelial submucosa. From these data, it was concluded that a significant difference in early clearance for particles exists between the ethmoid and maxillary turbinates, but there was no difference in the fraction of particles retained in these two areas for long periods of time.
Animals↗
Turbine flowmeter vs. Fleisch pneumotachometer: a comparative study for exercise testing.
The purpose of this study was to investigate the characteristics of a newly developed turbine flowmeter (Alpha Technologies, model VMM-2) for use in an exercise testing system by comparing its measurement of expiratory flow (VE), O2 uptake (VO2), and CO2 output (VCO2) with the Fleisch pneumotachometer. An IBM PC/AT-based breath-by-breath system was developed, with turbine flowmeter and dual-Fleisch pneumotachometers connected in series. A normal subject was tested twice at rest, 100-W, and 175-W of exercise. Expired gas of 24-32 breaths was collected in a Douglas bag. VE was within 4% accuracy for both flowmeter systems. The Fleisch pneumotachometer system had 5% accuracy for VO2 and VCO2 at rest and exercise. The turbine flowmeter system had up to 20% error for VO2 and VCO2 at rest. Errors decreased as work load increased. Visual observations of the flow curves revealed the turbine signal always lagged the Fleisch signal at the beginning of inspiration or expiration. At the end of inspiration or expiration, the turbine signal continued after the Fleisch signal had returned to zero. The "lag-before-start" and "spin-after-stop" effects of the turbine flowmeter resulted in larger than acceptable error for the VO2 and VCO2 measurements at low flow rates.
Carbon Dioxide↗
[Comparative measurements of standard drills and turbines].
Standard electric micromotors as well as accessory handpieces and right-angle handpieces were subjected to technical tests. Turbines with and without traction power (bearing power) were also studied. The rotational speed could be regulated on one turbine. Normal to high rotational speeds were obtained with electric micromotors when used in conjunction with the transferance attachment. The motors functioned well in terms of the linearity of rotational speed. The study of the rotational speed, regulation of rotational speed, and traction power of the turbines showed that the rotational speed and the possibility of so-called contact grinding of the turbine is equal to that of micromotors. In terms of grinding trauma to the pulp and gingiva, the indications shifted in favor of the turbine.
Dental Equipment↗
Suitability of a new turbine spirometer for epidemiological surveys in children.
The performance of a new turbine spirometer, which has several advantages over equipment previously used to measure lung function, was compared with that of a conventional spirometer (Vitalograph) in a cross-over trial on 368 children six to 11 years old. On average, slightly higher values of forced expiratory volume at 0.75 s and forced vital capacity were recorded on the turbine spirometer. These differences occurred mainly in children aged less than eight years. Assuming the Vitalograph remained accurate, there appeared to be a slight tendency for readings on the turbine spirometer to drift downwards at a rate of 0.04 1 per 100 children measured but this was not statistically significant (p greater than 0.10). In conclusion, the machines differed mainly in the youngest age group. Until a recording of the complete expiration curve can be made using the turbine spirometer, it is not possible to assess whether this effect of age arose because of errors in the breath manoeuvre by younger children undetectable in the turbine spirometer or because the simpler design of the spirometer makes it easier than the Vitalograph for young children to use it correctly.
Age Factors↗
Cryosurgery of the inferior nasal turbinates.
Forty-seven patients with irreversible nasal obstruction due to inferior turbinate hypertrophy were treated by cryosurgery, the short and medium term results having been clinically evaluated. Permanent good results in nasal breathing were achieved in 83% of the patients. Failures are mostly related to turbinates hypertrophy due to nasal allergy. The combination of cryosurgery and nasal septoplasty, in cases of hypertrophy associated with deformities of nasal septum, gives an excellent result. Cryosurgery of hypertrophic nasal turbinates is a simple, safe, and reliable procedure to improve nasal breathing in cases of nasal turbinate hypertrophy.
Adolescent↗
Covalent binding of [14C]-2,6-dimethylaniline to DNA of rat liver and ethmoid turbinate.
The xylidide 2,6-dimethylaniline (2,6-DMA) has produced carcinomas and papillary adenomas in the nasal cavity of rats at high dietary doses (3000 ppm) in a 2-yr bioassay. The objective of the present study was to measure the covalent binding of 2,6-DMA to DNA of rat ethmoid turbinate tissues and, for comparison, to DNA of rat liver. The potent hepatocarcinogen 2-acetylaminofluorene (AAF) was studied as a positive control for adduct formation and covalent binding index (CBI) calculation. Both 2,6-DMA and AAF were administered as 14C-(ring)-labeled agents to naive rats and to rats pretreated for 9 d with unlabeled 2,6-DMA or AAF. The CBI value for 2,6-DMA adduct formation with ethmoid turbinate DNA was below the assay's sensitivity limit in nonpretreated rats, but increased to 41.9 in rats pretreated with unlabeled 2,6-DMA. It also increased from 0.6 in nonpretreated to 7.9 in liver of pretreated rats. The opposite pattern, however, was observed for AAF. In nonpretreated rats considerable adduct formation was observed in liver (CBI = 271.5) and modest values (CBI = 39.3) were calculated for ethmoid turbinate tissues. Pretreatment with unlabeled AAF caused a significant decrease in CBI values, to 18.3 for liver and less than 0.5 for ethmoid turbinate. The results suggest that there may be value in conducting DNA covalent binding assays in both naive animals and animals pretreated with the test article.
Aniline Compounds↗
Treatment of obstructing inferior turbinates with intranasal corticosteroids.
The most common cause of nasal obstruction is chronic enlargement of the inferior turbinate bones. The variety of medical and surgical treatments available for this condition bears testimony to their frequent ineffectiveness and the frustration of the physician or surgeon caring for these patients. Removal or destruction of the inferior turbinates has received strong criticism from rhinologists, although at present there is renewed interest in turbinectomy combined with rhinoplasty. A technique employing intranasal injections of long-acting corticosteroids has been used successfully for over twenty years in treating obstructing inferior turbinates secondary to allergic and vasomotor rhinitis. The indications, technique, and complications of this method are reviewed; the technique is presented as an alternative to destruction or resection of the inferior turbinates.
Adrenal Cortex Hormones↗
Trimming of the inferior turbinates: a prospective long-term study.
The aim of this study was to determine whether the initial benefits of radical trimming and anterior trimming of the inferior turbinates on nasal airflow persisted in the long term. Radical trimming significantly reduced nasal resistance at 2 months following operation (n = 12) (P less than 0.005). There was no significant change in nasal resistance over the next 20 months. Symptom scores for nasal obstruction also showed a significant reduction (n = 16) (P less than 0.005), at 2 months, and did not change significantly over the next 20 months. Radical trimming of the inferior turbinates is a highly effective operation in patients with hypertrophy of the inferior turbinates with few initial complications. However, further analysis of the data revealed that up to 20% of patients lose the initial subjective benefit of relief of nasal obstruction within 2 years of follow-up. Late onset crusting occurs in some patients though this is not directly attributable to an increase in nasal airflow. This study also concludes that anterior trimming of the inferior turbinates cannot be recommended as a form of treatment.
Adolescent↗
Vaccine efficacy for reducing turbinate atrophy and improving growth rate in piggeries with endemic atrophic rhinitis.
Two vaccines, based on formalin-killed whole cells of toxigenic Pasteurella multocida type D and Bordetella bronchiseptica combined with a partially toxoided cell extract of P multocida, were prepared with Freund's incomplete adjuvant (vaccine 1) or by alum precipitation (vaccine 2). Each was tested for safety and efficacy in reducing the severity of nasal turbinate atrophy and improving the growth rate of pigs in three Western Australian commercial piggeries with endemic atrophic rhinitis. In safety experiments with vaccine 1, no adverse clinical effects were observed in vaccinated sows or their progeny. Piglets receiving vaccine 2 showed no injection site abnormalities, pyrexia or turbinate atrophy. In field trials, vaccine 1 significantly reduced the prevalence of moderate to severe nasal turbinate atrophy (Done score 3 to 5) when used in two piggeries (A and B). Progeny from vaccinated sows in piggery B also grew significantly faster than controls. When vaccine 2 was used in piggery A at a later date and in another piggery (C), growth rate was not improved in either piggery and the prevalence of moderate to severe turbinate atrophy was reduced only in piggery C.
Adjuvants, Immunologic↗