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cote interne IRCAM: Vergez98b; /; National audience; An artificial mouth with latex lips for trumpet-likeinstruments has been built. Four-track simultaneous recordings havebeen performed: acoustic pressure in the mouth, in the mouthpiece, andin the bell as well as the lips' opening area. Moreover, visualisation andfilming of the lips' movement has been done. Results are analysed in order tobetter understand the functioning of a brass instrument with the aim,among others, of improving our real-time model of trumpet.

BRUNSTROM, J. M., A. W. MacRAE, and B. ROBERTS. Mouth-state dependent changes in the judged pleasantness of water at different temperatures. PHYSIOL BEHAV 61 (5) 667–669, 1996.—Dehydration increases the pleasantness of cold (0°C) water (Boulze et al., 1983, Physiol. Behav. 30:97–102, 1983). The hypothesis that the mouth dryness induced by dehydration mediates this hedonic shift was investigated. Hydrated assessors ( n = 16) judged 3°C water as more pleasant after artificial mouth drying than did controls ( n = 16). Mouth drying failed to influence similar judgements of water 13°C, 23°C, and 33°C. We propose that preference shifts depend on temperature because cold water offers more rewarding relief from the sensations resulting from mouth dryness. Measures on saliva production were consistent with this proposal. Assessors swilled with water (3°C, 13°C, 23°C, and 33°C) for 5 s and then emptied their mouths. Measures of subsequent saliva flow confirmed that cold (3°C) water induces an elevated rate of saliva flow and consequently leaves the mouth in a wetter state.

cote interne IRCAM: Vergez97a; /; National audience; For several years, we have been developing and studying computer-simulated models of brass instruments, including the player's lips. We demonstrate here the most recent developments of our physical model, including physical functioning and real-time control with MIDI events. These improvements result in great improvements of sound quality and musical expressivity. To better understand the physics of real lips, we have built a working latex model of a pair of lips. We show that this artificial mouth can play a trumpet like a real trumpet player. We make comparisons between naturally blown trumpet signals, artificially-blown trumpet signals, and simulations with our computer model.

Most theoretical descriptions of the brass instrument lip-reed consider the acoustical condition at the lips to be a closed, rigid termination, corresponding to a unitary reflectance. This assumption is carried through to many computational models as well. In reality, the protrusion of the player's lips into the mouthpiece causes a periodic shortening/extension of the acoustical tube downstream, an effect sometimes but not always incorporated into such models. Of interest here is the absorption properties of the lip termination, the so-called “soft source impedance.” This provides a further modification to the boundary condition at the lips, since the soft, deformable nature of the lips are likely to cause some extra damping of the acoustic standing wave. Measurements are presented to demonstrate this damping effect using an artificial mouth. This is achieved through measurements of the lip reflectance from downstream of the lips, from where it is shown that the reflectance shows a dip at the peak absorba...

Mechanisms of salivary lubrication can be quantitatively measured by a reduction in the coefficient of friction. It is important that lubrication be assessed under the conditions of the oral cavity to properly assess lubrication regimes. The relative lubricity of three artificial salivas and two controls were assessed at a bovine enamel interface in an artificial mouth with a range of conditions that approximate oral function. Statistical analysis indicated that the enamel lubricity of sodium dodecylsul-fate (SDS) and Oracare-D saliva substitutes were different from the other saliva substitutes and water. The low friction with Oracare-D and SDS saliva substitutes was because of resident amphipaths adsorbed at the enamel interface. Amphipaths adsorbed on enamel may provide a reduction in interocculsal friction and its resulting complications for patients with xerostomia.

The objectives of this review are to compare the models that are used to simulate the caries process in cardiology research and to suggest how these models might be used to assess caries-inhibitory properties of dental materials. Available caries-simulation models fall into the following classifications: 1) in vitro demineralization using acid buffers, 2) in vitro demineralization using bacterially generated acids, 3) in vitro demineralization/remineralization using a pH-cycling system, 4) an artificial mouth where a bacterially generated acid challenge is interspersed with a "saliva" treatment, 5) in vivo animal model (generally with rats), 6) in situ demineralization and/or remineralization using enamel or dentin blocks or slices in the human mouth, and 7) in vivo studies using teeth scheduled for extraction in the human mouth. Most dental materials studies have used simple in vitro demineralization models or component release experiments, each of which is inadequate to answer the questions that are being asked about the caries-inhibitory properties of the material being tested. Experimental methods must be chosen with care to ensure that the material to be tested is examined in an appropriate mode. The ultimate goal is to correctly predict clinical outcomes. The design or redesign of a model must eventually be tied to documented clinical outcomes to improve the model and allow for future successful development of new materials.

International audience; The influence of the first and second resonance frequencies on tuning, timbre (or tone colour) and ease of playing is investigated for reed instruments, such as the clarinet, alto saxophone and oboe. Theoretical analyses of the eflects of the reed and the player embouchure (i.e. lip position and pressure on the reed) are reviewed, as well as the consequences of inharmonicity in the resonance frequencies. This review allows us to present interesting interpretations of the numerous experiments reported here. Three kinds of results are given: (I) comparison of playing frequencies andfirst resonance frequencies, for severalfmgerings with or without open register hole, leading to the deJinition of a frequency independent length correction for the embouchure; (2) examination of the eflect of inharmonicity of the two jirst resonance frequencies on both tone colour and ease of playing, the causes coming from either the player embouchure or the instrument construction; (3) comparison between theory and experiment for the inharmonicity produced by the changes in conicity in oboes, leading to an interpretation of the maker's choices. The results show how judicious use of simple tools, such as calculations or measurements of input impedance or playing data obtained using an arttjicial mouth, can be of help to the understanding of instrument construction and to the instrument designer.

Auditory self‐monitoring studies require the participants’ speech feedback to be manipulated experimentally and then presented to the ear. The acoustic levels of the altered speech must be the same as those under normal speech feedback conditions when speech is transmitted to the ear live, directly from the mouth. Therefore, it is critical to understand the transfer function between the mouth and the eardrum. To further this understanding, live and played‐back self‐generated speech for two female and two male individuals were recorded using a probe tube microphone inserted into the ear canal at a fixed distance from the tragus. The played‐back speech samples were delivered via a B&K artificial mouth, at the sound pressure level calibrated to match the level at the lips. The artificial mouth was placed offset to the participants right side and in line with the x and z axes of his/her mouth position. Recordings were conducted with the ears either open or sealed with ER‐3A insert earphones. In addition, the ...

The serpent is a lip‐excited wind instrument with an air column length of around 2 m and an approximately conical bore. In the form in which it emerged in France in the sixteenth century, it is a wooden tube with six finger holes and a chromatic compass of three octaves. The serpent suffers from some problems related to the fact that all the holes are covered directly by the fingers. The holes are grouped in two clusters, and the hole diameter is too small to provide adequate venting. The ophicleide, invented in the early nineteenth century, has a similar bore profile to the serpent. Eleven or more side holes in the thin‐walled metal tube are covered by lever‐operated padded keys; these allow most notes to be obtained without cross fingering, and the size and placing of the holes are not limited by the anatomy of the human hand. Several acoustical investigation techniques, including input impedance analysis, pulse reflectometry and excitation by an artificial mouth, have been used to investigate the extent to which the ophicleide is a successful solution to the acoustical problems posed by the serpent.

Simulated occlusal wear studies in an artificial mouth involving enamel occluding on porcelain demonstrated a high coefficient of wear for dental porcelain; in agreement with other workers, an abrasive wear process is postulated. Volume loss due to wear showed good linearity as a function of the number of masticatory cycles with slight flattening at higher masticatory levels. However, the depth of wear curve showed a pronounced deviation from linearity with flattening of the wear rate with time. A parabolic relation exists between volume and depth of wear and correspondingly between time and depth. Based on the coefficient of wear, the intrinsic wear of porcelain appears to be about one order of magnitude greater than that experienced by dental amalgam.

The pH and Eh of bacterial plaques produced on a tooth surface in an artificial mouth following inoculation with saliva, single cultures and mixed cultures were measured. The importance of these properties and the role of sucrose in controlling colonization by specific organisms, particularly anaerobes, was investigated. The degree of colonization was estimated from the viable counts in the effluent from the tooth. Interactions between the bacterial species in the multi-culture plaques are discussed. The results are presented in support of the hypothesis that colonization of the teeth by anaerobes depends upon prior growth of aerobes during early plaque formation.

The interaction of fluoride with plaque and the underlying enamel was studied in an artificial mouth after topical application of three different fluoride solutions. Streptococcus mutans

The retention and behaviour of fluoride contained in plaque and underlying enamel has been studied in the artificial mouth. Artificial plaque was grown either on bovine enamel or on platinum foil. At

Apparatus which enables the simultaneous continuous monitoring of pH and Eh of bacterial dental plaque as it develops on a tooth surface in an artificial mouth is described. Details of the electrodes used, monitoring equipment, and culture conditions are given. Preliminary results are given showing the Eh and pH values of plaque produced in vitro to be in close agreement with readings reported for plaque in vivo. The effect of the incorporation of 1% sucrose in the medium on these parameters is reported and a distinct inverse relationship between pH and Eh recorded.

口呼吸における口腔内外の気流の実態を把握するために, 流体力学的手法を用いて流れの可視化を行った. 可視化実験に先立って, 銅板製のヒト口腔3倍大矢状断模型で等電位線の測定を行い, 口腔内外の気流の傾向や概略が推測できた. 引き続いてプラスチック製の口腔模型を用いて, 色素法やアルミ粉トレーサー懸濁法による水流実験を行った. その結果としては, (1) 口腔に流入する空気は, とくに下唇下方からの流れが直接皮膚面に沿って進入する. (2) 口呼吸時の吸気の方向や速度は, 上下切歯の植立角度や開口度, また被蓋関係に強く影響される. (3) 前歯の被蓋関係が正常な場合, 上下切歯の切歯間を高速で通過した層流は, その幅を拡げることなく, 上顎切歯の口蓋面に沿って進み, この歯の歯肉に衝突したのち, 大部分は口蓋から若干離れて咽頭へ進む. (4)流れの可視化法は口呼吸の実態解明にきわめて有効な方法であると考える.

Fermenting sucrose, glucose and a simulated baby milk containing sugar and corn syrup produced lesions in enamel in vitro in an artificial mouth (the Orofax) which were significantl

Development and metabolic aspects of a monobacterial plaque of Streptococcus mutans C 67-1, inoculated on flattened human enamel slabs, were studied using an artificial mouth model.

Resonance of the mouth cavity while playing the flute has been found to occur near 1000 Hz. Experiments with an artificial mouth show the Q of this cavity is less than two when air is passing through the lips. The presence of this coupled cavity can affect the flute frequency by as much at 10 cents, and may increase the losses in the system by as much as one‐third.

To induce artificial mouth breathing on experimental animals has extremely been difficult because of its immediate death following nasal sealing treatment, and we could find only an imitating experiment reported by Butcher et al (J. Periodont. 32: 38, 1961). The purpose of this study is to induce absolute mouth breathing in rats and to investigate histopathological changes of their gingival tissues. Thirty six of Wister strain rats were equally divided into control and experimental groups. To induce absolute mouth breathing artificially, the nose of all experimental animals were sutured using thin wire and metallic buttones. After two weeks of experimental period, animals were sacrificed and materials were obtained.Consequently, we could find much more remarkable hyperkeratinization of epithelial layers in the experimental animals than the control. Inf lammatoric changes, however, were found in both groups of animals, but less in control. As the conclusion of this investigation, absolute mouth breathing may induce hyperkeratinization of the epithelial tissues, but does not initiate gingival inflammation following two weeks of experiment.

Sound human premolar teeth were incubated with Streptococcus mutans in an artificial mouth for 6 days. The enamel lesions produced were studied by microradiography and in polarized light. The lesions displayed an almost intact surface zone and a banded appearance in the underlying demineralized zone, although all the features of slowly progressing natural lesions were not seen.

The wear of dental amalgam by a smear mechanism and amalgam transfer onto the opposing cusp was confirmed by simulated studies in an artificial mouth. The coefficient of wear for dental amalgam was 4.89×10−5. Calculation of the coefficient of friction for the enamel/amalgam couple indicated that friction was overcome by shallow slippage and shear within the amalgam. On the basis of these facts, the good wear performance of both the amalgam and the opposing enamel was rationalized. A retrospective clinical correlation of amalgam wear in an artificial mouth showed a correlation coefficient of 0.938 as far as the mean wear values were concerned. Further the wear rates in both studies were linear except in a narrow region at time zero. The variances, however, in the 2 studies were very different. The desirability of in vitro studies to reproduce the same variance, as well as the same mean values, is a point for further discussion and experimentation.

A method for measuring frictional forces on enamel of natural teeth and restorative materials was developed using the Artificial Oral Environment. Enamel/enamel systems were tested using different oral fluids in a minienvironmental chamber capable of introducing biologic fluids between the occluding surfaces. Matched, extracted opposing human premolars mounted in physiologic occlusion under an occlusal load of 3 pounds were bruxed at approximate masticatory velocities. A load cell measured the resulting horizontal forces and an X-Y record was attained. 31 independent measurements of friction in both buccal and lingual directions were performed with the teeth dry, and with human saliva, Xerolube, and distilled water intervening. It was found that typical values for enamel/enamel coefficients of friction, μ, were in the range of 0.1–0.42. μ was independent of different fluids within any one enamel/enamel couple (coefficient of variation was typically 10%). However, the coefficient of friction of the enamel pair was highly dependent on surface texture. Roughening virgin enamel led to a 3 fold increase in μ. Conversely surfactants present in mineral oil reduced the friction of roughened enamel by 3 fold. Where the wear process is by abrasion it is likely that the reduction of the tangential forces due to friction could lead to reduced loss of contour. It is likely that finishing procedures in dentistry are important in this process. Finally, the production of low friction restorative materials are clearly indicated as a future development.

The oral cavity supports a great diversity of micro-organisms, ranging from aerobes to strict anaerobes. The tooth surface, saliva and soft tissues each contain their own commensal flora. Dental plaque, the microbial community on the tooth surface, has been the subject of much investigation because of its role in the aetiology of both dental caries and periodontal disease. Two different approaches have been used to simulate the oral environment in an attempt to understand microbial behaviour in the mouth: one of these is the artificial mouth, the other is the chemostat.

Simulated occlusal wear utilizing the artifical mouth included natural enamel against isosit and polymethyl methacrylate splint materials. The results reported in volume loss (mm 3 ) demonstrated the isosit material to be 55–67% more resistant to wear than polymethyl methacrylate. No wear occurred on the enamel surface opposing either splint material.

Bacteriocinogenic strains of Streptococcus salivarius antagonized Strep. sanguis on blood agar and in Todd-Hewitt broth with, but not without, sucrose. Each organism produced plaque in vitro but, after a mixed inoculum with both organisms, the numbers of Strep. sanguis rapidly fell to

The plaque-producing properties of Streptococcus sanguis, Streptococcus salivarius, Streptococcus mutans, Streptococcus mitis and Streptococcus faecalis were investigated in an artificial mouth with continuous supply of nutrient. Attention was focused on the role of salivary factors and sucrose in tooth colonization. Plaque formation by single cultures depended on the ability to produce tenacious extracellular polysaccharide or to cohabit the tooth with an organism having this property. Sucrose was the only essential additive to nutrient broth necessary for plaque formation and could not be substituted by sterile natural saliva. Saliva neither facilitated colonization by Strep. mitis nor prevented colonization by Strep. salivarius as may have been supposed from previous reports.

The wear of a posterior composite against a maxillary palatal cusp was studied in an artificial mouth. The coefficient of wear for the composite was 2.58×10 −5 . A retrospective clinical correlation with composite wear in the artificial mouth showed a correlation coefficient of 0.84 at 1 year of wear. The artificial mouth studies support a parabolic relationship between depth of composite wear and time. The ratio of 6 months depth of wear compared to 3 years was found to be 41% which supports the Leinfelder finding (5) of 49%. However, the correlation with the linear studies of Braem (2,3) was good as far as the mean depth of wear at 1 year was concerned. The disagreement between the linear and parabolic studies is small during the early wear process, but becomes serious during a longer term. It is important for future clinical wear studies to resolve the question of the nature of the wear rate curve in posterior composites, if accurate prediction of long term performance is to be achieved.

The integration of two closed mechanical loops was used to produce a force-movement cycle, using servo-hydraulics. Several of the parameters were of interest in clinically-simulated laboratory studies. The system represented the first phase in developing an artificial oral environment.

A new system for in vitro decalcification, the agar-saliva method, has been used to produce gross carious lesions which closely resemble, by all available criteria, those produced by the carious process in the mouth. In addition, incipient lesions have been formed rapidly and have been found to be indistinguishable histochemically and microradiographically from natural lesions. The method is rapid and effective for evaluating anticaries agents, as determined by comparing materials whose action in clinical trials has been reported in the literature. A similar discrimination of known agents was produced by the use of the Pigman artificial mouth. Stannous fluoride (2%) was shown to be a more effective agent than sodium fluoride (2%), a result which agrees with clinical reports. In comparisons at lower concentrations, stannous fluoride was found to be even more strikingly superior to sodium fluoride in preventing decalcification in the in vitro system. A dentifrice containing stannous fluoride was found to be an effective agent against decalcification. The caries reducing effect of this dentifrice has been shown in clinical studies. The more effective application of the dentifrice was found to be a brushing technique, as opposed to a simple covering of the teeth with the paste. Examples have been shown to illustrate visual, fluorescent, transmitted light and microradiographic techniques for evaluating progress of decalcification in in vitro systems.

THE artificial mouth is a device for simulating in vitro the principal oral conditions presumably involved in dental caries1. Qualitatively, the in vitro lesions produced in human teeth are similar to those produced naturally2–4. The method has been used for the quantitative evaluation of anti-caries agents and dentifrices5–7.

For the work described in this report, freshly extracted teeth were mounted in plastic boxes and the surfaces were photographed at a magnification of about 8×. The mounted teeth were placed in cylindrical glass funnels and a bacteriologic medium was allowed to flow dropwise over the individual teeth. The teeth were inoculated at weekly intervals by soaking for thirty minutes in a sample of pooled saliva. Usually at regular intervals, the teeth were examined at a magnification of 30× and photographed when necessary. Under these conditions, lesions of the enamel have been produced which are very similar in appearance and position to natural carious lesions. By the use of bilaterally identical teeth, it has been shown that tooth surfaces brushed twice daily remain fairly sound for long periods, whereas unbrushed or roughened areas soften rapidly. Typical regions of attack of brushed teeth are developmental pits and grooves, particularly on the occlusal surfaces, proximal surfaces, and cervical areas near the cementoenamel junction. The mode of attack is quite different when a strictly decalcifying medium is used without bacterial development. Individual teeth exhibit considerable difference in resistance to enamel attack. Apparently deciduous and unerupted teeth are much less resistant than old erupted teeth. Enamel attack has been observed only when glucose is present in the media, and when streptococci, lactobacilli, or both have developed. In the absence of glucose, the tooth surfaces remain intact for long periods. Dentine is decalcified under these conditions, but usually the structure is retained. Some instances of dentine destruction have been noted; in current investigations the conditions necessary for dentine destruction are under active investigation.

This work aimed at analysing bread extracts obtained under headspace and artificial mouth conditions in order to study the reactions responsible for bread flavour quality. Selected extraction conditions were first compared according to the odour and aroma representativeness of the bread extracts. The optimal conditions were then ap - plied to extract volatiles of a conventional gluten bread formulation and an innovative gluten-free bread formulation. Results reveal that an extraction duration of 10 min in the artificial mouth was sufficient to obtain a representative aroma extract. Yet, 30 min of headspace extraction were necessary to obtain a representative odorant extract. The comparison between these both extracts shows that significantly higher quantities of bread compounds were extracted with artificial mouth. This innovative device could thus be used to better understand the mechanisms involved in the formation of those volatiles that are responsible for the perceived bread odour and aroma.

Computer-aided design and computer-aided manufacturing (CAD–CAM) enable subtractive or additive fabrication of temporary fixed dental prostheses (FDPs). The present in-vitro study aimed to compare the fracture resistance of both milled and additive manufactured three-unit FDPs and bar-shaped, ISO-conform specimens. Polymethylmethacrylate was used for subtractive manufacturing and a light-curing resin for additive manufacturing. Three (bars) and four (FDPs) different printing orientations were evaluated. All bars (n = 32) were subjected to a three-point bending test after 24 h of water storage. Half of the 80 FDPs were dynamically loaded (250,000 cycles, 98 N) with simultaneous hydrothermal cycling. Non-aged (n = 40) and surviving FDPs (n = 11) were subjected to static loading until fracture. Regarding the bar-shaped specimens, the milled group showed the highest flexural strength (114 ± 10 MPa, p = 0.001), followed by the vertically printed group (97 ± 10 MPa, p < 0.007). Subtractive manufactured FDPs revealed the highest fracture strength (1060 ± 89 N) with all specimens surviving dynamic loading. During artificial aging, 29 of 32 printed specimens failed. The present findings indicate that both printing orientation and aging affect the strength of additive manufactured specimens. The used resin and settings cannot be recommended for additive manufacturing of long-term temporary three-unit FDPs.

This study shows the potential risk of microfiltration between two different types of implant-abutment connections screwed at 45 Ncm: external and internal. For the first time the use of a mechanical artificial mouth is used with the values (compression and torsion loads with a frequency of 2 Hz) of the human chewing. The mechanical tests were performed with an artificial saliva at 37 degrees C. The microgap in the connection was measured by an Image Analysis software incorporated in a high resolution scanning electron microscopy. Implant connections were filled with methylene blue by using self-adjustable precision pipettes and the quantity of leakage was determined by high sensitivity spectometry. We showed that the internal connection has lower microgaps compared to the external ones and these microgaps increased with the number of mechanical cycles. The leakage of methylene blue was higher when the external connection was performed. Microgaps and the influence of the mechanical loads are very important for the long-term behavior avoiding the bacteria colonization in the dental implants. These aspects should be known by the implantologists. info:eu-repo/semantics/acceptedVersion

A miniature continuous culture apparatus is described which allows production of plaque on the surface of pH and Eh electrodes under continuous culture conditions. Continuous monitoring of pH and Eh of uninterrupted plaque was possible and the application of the apparatus to the study of plaque, salivary sediments and saliva collected from man is suggested. Plaque resembling that produced in an artificial mouth and that observed in vivo was developed in this apparatus in 8 hr.

When calibrated and operated at different distances, available artificial voice/mouth frequency response measuring systems yield significantly different results. These differences are greater for different distances than for different voice/mouths. Virtually all reported voice measurements are made at the CCITT recommended distance of 25 mm from the lips, or 25 mm in front of the “lip ring” of the artificial voice/mouths. Yet, all high‐noise environment military microphones are tested 1/4 in. (6 mm) from the voice/mouth opening. This is, however, several millimeters behind the lip plane of the voices. At this distance, noise canceling microphones show minimal cancellation effects. Historically, the use of 1/4‐in. distance began with a laboratory artificial voice/driver sound system, which predated the first commercially available, relatively large scale production artificial voice (B&K 4216). This paper shows the feet(s) on measured microphone response when military noise canceling microphones (M‐138, H‐2...

Reed vibrations have been observed for the lowest notes of a bassoon, an oboe, a clarinet, and a soprano saxophone artificially blown. The blowing pressure in the artificial mouth used has been increased from 1.5 k Pa to about 10 kPa (20 kPa for the oboe) and decreased. The relative position and contact pressure between the lips and reeds have been fixed during a cycle of changes in the blowing pressure. Conclusions: (1) Many different modes of very stable periodic vibrations are found even under the same blowing pressure. (2) A slow continuous change in blowing pressure causes a sudden transition from one mode to the next without a change in the lip‐reed relative position; this in turn gives rise to some change in the blowing pressure. (3) Which mode is excited under a given blowing pressure depends on the sequence of the preceding modes. (4) In the bassoon and oboe, not all the transitions are reversible; with blowing pressure being increased and decreased, the sequence of modes encountered exhibits hys...

Attention is drawn to the advantages of the so-called “artificial mouth” in investigations into experimental lesions similar to caries. The design of an all-glass apparatus suitable for multiple operation is described. Continuous and intermittent flow feed systems and a siphon for supplying Seitz filtered saliva have been evolved. The methods used for mounting and sterilizing the experimental teeth are described. It has been possible to produce, by salivary inoculation, a bacterial plaque on a sterile tooth surface.