Mouthpiece Design Research Articles

Historical Clarinet Mouthpieces: An Analysis and Re-creation studyHistorical Clarinet Mouthpieces: An Analysis and 3D Re-creation study

The mouthpiece of a clarinet plays a crucial role in sound formation and tuning, and there is still great potential for research within the field of historical clarinet mouthpieces. This study explores the relationship between mouthpiece shape and performance practice in the first half of the 19th century when significant changes occurred in clarinet history. The author examines historical mouthpieces from various collections and creates 3D-printed replicas for experimentation. The research investigates how mouthpiece shape relates to changes in reed positioning and national styles, and how 3D printing technology can aid in understanding historical mouthpiece design. The study finds evidence of a causal relationship between changes in reed positioning and mouthpiece geometry, especially reflected in the dimension of the mouthpiece window. The creation of a functional 3D-printed historical mouthpiece and experimentation with variations in shape shed light on how different parameters of the mouthpiece geometry affect the sound response. The research offers a useful tool for historical clarinet players to choose mouthpieces in a more historically informed way.

Effects of the mouthpiece and chamber of Turbuhaler® on the aerosolization of API-only powder formulations

Powder dispersion in dry powder inhalers (DPIs) is affected by powder formulations as well as the design of a device. This paper conducted a numerical investigation based on the coupled computational fluid dynamics (CFD) and discrete element method (DEM) to evaluate the changes of the design of a commercial DPI device Turbuhaler® on the aerosolization of an API-only formulation. Six different designs were proposed by modifying the mouthpiece and chamber of the original geometry which was reconstructed from a CT-scan of the Turbuhaler, and their performances in terms of powder deposition in the device and fine powder fraction (FPF) were evaluated. The resistance of the device was observed to vary with different designs. For the change of the mouthpiece, the device with a cylindrical mouthpiece had the least resistance and the lowest FPF emitted among all the devices, confirming the important role of the spiral mouthpiece on powder dispersion. Reducing the mouthpiece size caused more powder deposition in the inhaler due to higher airflow velocity, but FPF emitted increased compared to the original design as more powder dispersion occurred inside the mouthpiece. The half-length mouthpiece design reduced device resistance to increase airflow velocity and average collision energy, resulting in an increase in FPF loaded but a decrease in the number of collisions. For the change of the chamber, the domed chamber design increased the powder dispersion time and thus enhanced the frequency and energy of particle collisions, which eventually led to an increase in FPF loaded. At fixed flow rates, the powder dispersion efficiency was a function of the device resistance with higher device resistance causing an increase in the FPF loaded. However, it is important for the patient’s attainable pressure drop to be considered in this context. Correlations between the aerosolization efficiency and the ratio of the average collision energy and cohesion energy were established based on model-predicted quantities.

Towards 3D printed saxophone mouthpiece personalization: Acoustical analysis of design variations

Saxophonists have different expectations from the saxophone mouthpiece, as it significantly affects the playability and the sound of the instrument. A mass personalization paradigm provides unique products to cater to their needs, using the flexibility of additive manufacturing. The lack of quantitative knowledge on mouthpiece design hinders the personalization attempts. This study aims to lay out how design parameters affect mouthpiece characteristics. Twenty-seven 3D-printed mouthpieces with varying design parameters are used in conjunction with an artificial blowing machine, to determine the acoustical relevance of the various mouthpiece designs on four selected mouthpiece features. The influence of the design parameters is evaluated statistically and via a case study with five saxophonists. The analysis shows that seven out of nine parameters tested affect the mouthpiece characteristics by relatively different amounts. A user study demonstrates that saxophonists confirm the results in 7 of 10 cases, and they prefer personalized mouthpieces in 4 of 5 cases. The results present a key contribution to the understanding of mouthpiece design. The findings provide valuable insights for new mouthpiece design and mouthpiece personalization.

Effect of the welding burner mouthpiece design on the gas dynamics of the expiration of the protective gas jet

Effect of the welding burner mouthpiece design on the gas dynamics of the expiration of the protective gas jet

Two methods for acoustic modeling of the saxophone mouthpiece

The mouthpiece is one of the key components in determining the sound and the playability of the saxophone. Assuming plane-wave propagation inside the mouthpiece, two different models are proposed for acoustic modeling of the saxophone mouthpiece. First, a Transfer Matrix (TM) model is derived from a finite element model and is then validated by comparing the calculated input impedance of a mouthpiece-cone structure with measurements. Then, by adapting a methodology traditionally used in modeling the human vocal tract, a Geometric Model (GM) is used to approximate the mouthpiece as a series of acoustic tubes of varying cross-sectional areas, and its accuracy is examined by comparing it with the TM mouthpiece model. We couple both models to a measured input impedance of an alto saxophone and provide a comparison of both methods and their impact on different fingering configurations. Finally, we discuss applications in sound synthesis and in mouthpiece design.

Spiral mouthpiece design in a dry powder inhaler to improve aerosolization

This study presents the effect of a spiral mouthpiece design in a carrier-based dry powder inhalation on particle aerosol characteristics. Two kinds of mouthpieces, with spiral and non-spiral shaped flow channels, were fabricated by 3D-printing; particle image velocimetry and Anderson cascade impactor were performed to evaluate the drug aerosol characteristics. The obtained experimental results were in agreement with the simulation results of the computational fluid dynamics analysis. The spiral channel created a strong swirl motion of the air flow emitted from the mouthpiece exit, which produced angular momentum rather than the axial flow velocity in the forward direction. This is beneficial in terms of liberating the micronized drug particles from the carrier surface, and leads to more effective delivery of these drug particles to the peripheral target regions of the respiratory system. The spiral device could produce drug particles with significantly smaller mass median aerodynamic diameters and higher fine particle fraction than the non-spiral device.

Assessing temporomandibular disorders: Mouthpiece design considerations

Background/Aim. Scuba diving is one of the sports with the fastest growing popularity. Nowadays doctors of dental medicine meet divers-patients in their offices more often. Treatment of these patients has some specific features that are related to difficulties in the temporomandibular joint, masticatory muscles and soft tissues of the oral cavity. A set of those complaints represent a condition called ?diver's mouth syndrome?. Most scuba divers complain of temporomandibular joint and the masticatory muscles pain; inadequate mouthpieces can exacerbate temporomandibular dysfunction (TMD) even when its symptoms are not present in everyday life. The aim of this research was to find a decent substitute for a fully customised mouthpiece, that are not present at our market, to discover the qualities of a good mouthpiece and establish prevalence of TMD among divers. Methods. This study included 30 scuba divers. Scuba divers filled out the questionnaire before diving, then dived twice with each of the 3 different commercial mouthpieces provided for this research (Mares Universal, Seac sub, Mares LiquidSkin (Universal Mares, Seac sub, Mares LiquidSkin). After diving, they filled out the second part of the questionnaire and so they performed an assessment of the mouthpiece and gave insight into the prevalence of TMD symptoms caused by using the mouthpiece. Results. According to the average score of satisfaction (the least present symptoms such as pain, fatigue, and numbness of the masticatory muscles and the jaw joint), this research proved Mares LiquidSkin mouthpieces to be the best out of the 3 commercial mouthpieces. For its use, average satisfaction score among participants was 7.07 (out of 10) and none of the divers reported jaw and muscle stiffness during and after the dive with this mouthpiece. The smallest percentage of participants reported pain in the orofacial region and discomfort while swallowing when used it in comparison with other mouthpieces. The anatomy and material of the mouthpieces turned out to be an extremely important factor. Conclusion. Several factors contribute to a good mouthpiece design; the choice of material, its elasticity and softness, the thickness and length of the interdental bite platform and the width of the oral screen that is inserted into the vestibule. The preferred material should be soft silicone. The interdental bite platforms should support the posterior teeth and the oral screen should fit the jaws and not be too wide.

Prerequisites for a dry powder inhaler for children with cystic fibrosis

Correct inhalation technique is essential for effective use of dry powder inhalers (DPIs), as their effectiveness largely depends on the patient’s inhalation manoeuvre. Children are an especially challenging target population for DPI development due to the large variability in understanding and inspiratory capacities. We previously performed a study in which we determined the prerequisites for a paediatric DPI in a mostly healthy paediatric population, for which we used an empty test inhaler with variable internal airflow resistance and mouthpiece. In the current study we investigated what specifications are required for a DPI for children with cystic fibrosis (CF), for which we expanded on our previous findings. We recorded flow profiles of 35 children with CF (aged 4.7–14.7 years) at three airflow resistances (0.031–0.045 kPa0.5.min.L-1) from which various inspiratory parameters were computed. Obstructions in the mouth during inhalation were recorded with a sinuscope. All children were able to perform a correct inhalation manoeuvre, although video analysis showed that children did not place the inhaler correctly in the mouth in 17% of the cases. No effect was found of medium to high airflow resistance on total inhaled volume, which implies that the whole resistance range tested is suitable for children with CF aged 4–14 years. No effect could be established of either mouthpiece design or airflow resistance on the occurrence of obstructions in the mouth cavity. This study confirms our previous conclusion that the development of DPIs specifically for children is highly desired. Such a paediatric DPI should function well at 0.5 L inhaled volume and a peak inspiratory flow rate of 20 to 30 L/min, depending on the internal airflow resistance. This resistance can be increased up to 0.045 kPa0.5.min.L-1 (medium-high) to reduce oropharyngeal deposition. A higher resistance may be less favourable due to its compromising effect on PIF and thereby on the energy available for powder dispersion.

Prevalence of dental problems in recreational SCUBA divers: a pilot survey.

Objective To determine the prevalence of dental symptoms in recreational scuba divers and describe the distribution of these symptoms on the basis of diver demographics, diving qualifications and dive conditions during the episode of dental pain.Design A survey was designed and distributed through online social media platforms dedicated to scuba diving. A convenience sample of 100 recreational divers was obtained by this method.Main outcome measures The outcome measures of interest were: diver demographics, diving characteristics (level of certification, number of dives completed), occurrence of dental problems during a dive, and details of the episode.Results Forty-one percent of the respondents experienced dental symptoms during a dive. Barodontalgia was the most frequently experienced dental symptom during a dive.Conclusion Within the limits of the small sample size and online method of recruitment, the findings of this study suggest that a high proportion of recreational divers may experience dental symptoms during a dive. It would be meaningful to ensure that dental decay and damaged restorations are addressed before a dive and that the mouthpiece design be evaluated in case of complaints of temporomandibular discomfort during a dive.

Influence of wearing a scuba diving mouthpiece on the stomatognathic system - considerations for mouthpiece design.

Although diver's mouth syndrome (DMS) has long been recognized by scuba divers, little attention has been paid to the influence of wearing a scuba diving mouthpiece on the stomatognathic system. In this review, DMS-related stomatognathic events (DMS-SE) while wearing a mouthpiece, the relationship between components of the mouthpiece and those events, and design considerations to reduce the risk of those events are discussed based on evidence from 32 articles concerning scuba diving mouthpieces. Forward movement of the mandible, loss of molar occlusal support, and continuous jaw clenching while wearing a mouthpiece are considered to be pathogenic for DMS-SE. Several experimental studies have suggested a relationship between incidence of those events and the design of mouthpiece components such as the connector, labial flange, platform, and occlusal rug, and the possibility of reducing risk of those events through design customization of these components. Improvement of the shape of commercially available mouthpieces and creation of custom-made mouthpieces may thus contribute to the prevention and treatment of DMS-SE and the provision of a comfortable diving environment.

Effect of inhaler design variables on paediatric use of dry powder inhalers.

Age appropriateness is a major concern of pulmonary delivery devices, in particular of dry powder inhalers (DPIs), since their performance strongly depends on the inspiratory flow manoeuvre of the patient. Previous research on the use of DPIs by children focused mostly on specific DPIs or single inspiratory parameters. In this study, we investigated the requirements for a paediatric DPI more broadly using an instrumented test inhaler. Our primary aim was to assess the impact of airflow resistance on children’s inspiratory flow profiles. Additionally, we investigated children’s preferences for airflow resistance and mouthpiece design and how these relate to what may be most suitable for them. We tested 98 children (aged 4.7–12.6 years), of whom 91 were able to perform one or more correct inhalations through the test inhaler. We recorded flow profiles at five airflow resistances ranging from 0.025 to 0.055 kPa0.5.min.L−1 and computed various inspiratory flow parameters from these recordings. A sinuscope was used to observe any obstructions in the oral cavity during inhalation. 256 flow profiles were included for analysis. We found that both airflow resistance and the children’s characteristics affect the inspiratory parameters. Our data suggest that a medium-high resistance is both suitable for and well appreciated by children aged 5–12 years. High incidences (up to 90%) of obstructions were found, which may restrict the use of DPIs by children. However, an oblong mouthpiece that was preferred the most appeared to positively affect the passageway through the oral cavity. To accommodate children from the age of 5 years onwards, a DPI should deliver a sufficiently high fine particle dose within an inhaled volume of 0.5 L and at a peak inspiratory flow rate of 25–40 L.min−1. We recommend taking these requirements into account for future paediatric inhaler development.

Internal mouthpiece designs as a future perspective for enhanced aerosol deposition. Comparative results for aerosol chemotherapy and aerosol antibiotics

In an effort to identify factors producing a finest mist from Jet-Nebulizers we designed 2 mouthpieces with 4 different internal designs and 1-3 compartments. Ten different drugs previous used with their "ideal" combination of jet-nebulizer, residual-cup and loading were used. For each drug the mass median aerodynamic diameter size had been established along with their "ideal" combination. For both mouthpiece, drug was the most important factor due the high F-values (Flarge=251.7, p<0.001 and Fsmall=60.1, p<0.001) produced. The design affected the droplet size but only for large mouthpiece (Flarge=5.99, p=0.001, Fsmall=1.72, p=0.178). Cross designs create the smallest droplets (2.271) so differing from the other designs whose mean droplets were greater and equal ranging between 2.39 and 2.447. The number of compartments in the two devices regarding the 10 drugs was found not statistically significant (p-values 0.768 and 0.532 respectively). Interaction effects between drugs and design were statistically significant for both devices (Flarge=8.87, p<0.001, Fsmall=5.33, p<0.001). Based on our experiment we conclude that further improvement of the drugs intended for aerosol production is needed. In addition, the mouthpiece design and size play an important role in further enhancing the fine mist production and therefore further experimentation is needed.

Abstracts: International Society for Aerosols in Medicine19th International CongressChapel Hill, North Carolina, USAApril 6–10, 2013

Children are an important target group for inhalation therapy, but little is known about their intellectual and inspiratory capacities to operate dry powder inhalers (DPIs). Most studies so far have focused either on a specific DPI, or on (single) inhala- tion parameters and how these are affected by airflow resistance, which leaves many questions for the development of new devices for the pediatric population unanswered. In this study, we investigated the applicability of DPIs in children by a more systematic approach by using a test inhaler with variable airflow resistance and exchangeable mouthpiece design. The test inhaler was instrumented to record inhalation curves and equipped with fiberglass optics (sinuscope) to study the passageway for the aerosol through the mouth cavity. We examined for 103 school children (aged 4-12 years) whether they were able to use the test inhaler according to the instructions given. Nearly all (91) were able to perform one or more correct inhalations. We computed PIFs, inhaled volumes, and inhalation times from in total 256 recordings, and tested relationships with height and airflow resistance upon significance. We also noted preferences for airflow resistance and mouthpiece design, and investigated how these variables affect the inhalation maneuver. Ultimately, we aim to use the data from this study not only for prescribing the most appropriate type of currently marketed DPI to children, but particularly to design a new DPI that performs well within the range of inspiratory capacities (PIF and inhaled volume) to be expected for children.

Influence of Mouthpiece Geometry on the Aerosol Delivery Performance of a Dry Powder Inhaler

To investigate the influence of mouthpiece geometry on the amount of throat deposition and device retention produced using a dry powder inhaler (Aerolizer), along with the subsequent effect on the overall inhaler performance. Computational Fluid Dynamics analysis of the flowfield generated in the Aerolizer with various modified mouthpiece geometries (including cylindrical, conical and oval designs) was used in conjunction with experimental dispersions of mannitol powder using a multi-stage liquid impinger to determine how the overall inhaler performance varied as the mouthpiece geometry was modified. Geometry of the inhaler mouthpiece had no effect on device retention or the inhaler dispersion performance. In contrast, the mouthpiece geometry strongly affected the amount of throat deposition by controlling the axial component of the exit air flow velocity. The radial motion of the emitted aerosol jet was found to have little effect on throat deposition in representative mouth-throat models. Despite the reduced throat deposition, there was no difference in the overall inhaler performance. For cases where low throat deposition is a key design parameter, this study demonstrates that the amount of throat deposition can be reduced by making minor modifications to the inhaler mouthpiece design.

Prevalence of temporomandibular dysfunction in a group of scuba divers

Background: Temporomandibular dysfunction (TMD) has been reported to be a common problem in divers, with a prevalence of up to 68%. No evidence for this is available. Objective: To investigate...

Design characteristics of nineteenth century American-made brass instruments

The brass band was arguably the most popular form of entertainment for most American citizens in the nineteenth century. This ensemble flourished in nearly every town and eventually led directly to the development of jazz, the basis for all American popular music in the twentieth century. American brass instrument design underwent significant changes in a relatively short period of time during the second half of the nineteenth century. These design changes resulted in noticeable variations in instrumental timbre, changes that clearly had an effect on the music written for wind bands during this period. This presentation will feature two complete sets of nineteenth century brass band instruments, one from the Civil War era and one from the end of the century. They will be analyzed from the following perspectives: design specifications of bore, bell shape, valve configuration and mouthpiece design; weight and thickness of metal; and instrument timbre as demonstrated in live performance. It is hoped that the comparison of design characteristics followed by the actual sounds of the instruments will offer insights into this most important of relationships for the musician.

Alternative mouthpiece design for viewing the lip reed in motion

Mouthpieces for stroboscopic viewing of the lip reed have been designed for the full range of brass instruments, from trumpet to tuba. In order to provide an unobstructed frontal view of the lips, the axis of the backbore has been rotated 90° from the axis of the rim, so that it emerges from the side of the cup. This is similar to the original design of Daniel W. Martin [J. Acoust. Soc. Am. 13, 305–308 (1942)]. Flat end windows are desirable for avoiding optical distortion, but they limit the range of viewing angles. Placement of the lips on the rim and the angle of the air channel between the lips can vary noticeably from performer to performer, so a flat window that works well for one embouchure may be quite inadequate for another. The large cup volumes of the low brass mouthpieces allow for greater flexibility in design without getting into severe distortion. A cylindrical end window with its axis parallel to that of the rotated backbore provides a wide range of viewing angles. A preliminary survey of embouchures used by beginning and advanced trombone players will be presented. [Work supported in part by the Scholarly and Creative Activities Committee at CSULB.]

Comparison of two different mouthpieces for the measurement of Pimax and Pemax in normal and weak subjects

We investigated the effect of mouthpiece design on maximum static expiratory (PEmax) and inspiratory (PImax) mouth pressures. We measured PEmax from total lung capacity (TLC) and PImax from residual volume (RV) in 21 healthy volunteers, and in 40 patients referred for respiratory muscle testing. We compared two different mouthpieces, a semi-rigid plastic flanged type fitting inside the lips, and a 4 cm diameter rubber tube held against the lips. The tube mouthpiece gave significantly higher values for PEmax (p less than 0.02) in all subjects. PImax was also significantly higher (p less than 0.005) with the tube mouthpiece in subjects who recorded normal pressures. We conclude that maximum pressures are obtained in all normal subjects with the rubber tube mouthpiece, and that differences in quoted normal ranges of maximum static respiratory pressures reflect in part the design of the mouthpiece and the way in which it was used.

Dental factors in Scuba mouthpiece design.

Dental factors in Scuba mouthpiece design.