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Measurement of perioral pressures during playing of musical wind instruments
Measurement of perioral pressures during playing of musical wind instruments
IS well known that biologic changes occur in the t,issucs surrounding the root of the tooth when extraneous forces arc applied to the crown. Rrsorption and deposition of bone, as well as fibrillar reorientation within the periodontal ligament, permit alteration in the position ol’ a tooth when prolonged forces arc applied. Embouchure, the manner of applying the lips and teeth to the mouthpiece of a musical wind instrument, may produce sufficient pressure on the teeth to cause tooth movement. This study was initiated to measure and evaluate the amount of pressure exerted by the upper lip against. the maxillary anteriol teeth of various musicians playing different instrumrnts. In 1939, Strayer1 classified instruments according to type 01 monthpiecc: and rccommcnded that, specific instrmricnts bc selcctcd for their bcricficial influencc on esisting malocclusion. Schultz,” I lrubp and Kessler,:’ Kessler,+‘; Frank.’ and IIeskia and Hospitals hale made similar suggestions. On the other hand, musical instruments may be chosen to fit the prevailing malocclusion from the ease-of-playing standpoint, without regard to anp detrimental influence that may bc cscrtcd on the dentition.+” The significance of circumoral muscle influence has been mentioned. Tulley\-l’ theorized from electromyographic observation that a lip cont,raction greater than the pressures exerted by the tongue caused retroinclination of the incisors. Portcr’sl” studies supported the theory that forces resultZing from the playing of musical instruments affect. the dentit,ion. Rogers I-~-Mclinically demonstrated the place of myofunctional therapy in corrcctin, 0‘ malocclusion and in aiding normal development of the dentofacial complex. Strengthening of the pcrioral musculature by playin, 0‘ a musical instrument may aid in maintaining a normal occlusion following orthodontic correction. A numhcr of research studies hare IT
856
Perioral
pressures a.7ld musical wind instruments
857
been directed toward assessment of the balance between lip and tongue forces.17-28 Generally, the investigators concluded that the tongue is capable of producing a greater maximum muscle force than the lips. Of the various devices used to measure muscle pressures, the most accurate have been the electronic strain gauges. WinderP” attached gauges to the labial surface of a maxillary incisor and measured the maximum pressure, resting pressure, and swallowing pressure of the perioral musculature. He established this method as a reliable means of recording labial forces. In contrast to the opinions just mentioned, the Alameda Instrument Study demonstrated that the playing of musical instruments or the type of instrument played had little effect on tooth position, provided the patient was using correct embouchure and was under proper supervision.‘” In the present study an attempt has been made to answer the following questions: What is the magnitude of the perioral force involved in playing a musical wind instrument? And what is the variation of this force from subject to subject? What is the relationship between instrumental pressure and other pcrioral forces? No previous study has attempted to measure the forces produced by musical instruments. METHODS
ASD
MATERIALS
In order to measure the lingually directed force of the upper lip against the maxillary incisors during the playing of a musical instrument, an intraoral pressure transducer was designed to meet the following requirements : (1) sufficiently small bulk so as not to interfere with playing of the instrument; (2) sensitivity over a range consistent with the pressures to be measured; (3) adaptability to various subjects; and (4) accurate repositioning in a given subject,. The pressure-sensitive element of the device constructed for this study was a transducer,* consisting of a wafer 6 mm. in diameter and 1.5 mm. thick. The clement, was made of two brass terminal plates between which was a layer of pressure-sensitive paint composed of rare-earth materials. The pressure transducer had a minimum resistance of 1,000 ohms and a pressure range of from 0 to 2.5 pounds. This transducer, because of the properties of the rare earths, exhibited a decrease in electrical resistance as pressure against it increased. The resultant change in voltage was amplified and recorded by means of a preamplifier and an ink-writing oscillograph.+ The intraoral apparatus consisted of a fixator-carrier by means of which the apparatus was retained and stabilized against the maxillary dentition and transmitted pressure to the transducer element (Fig. I). Two rectangular metal t.roughs, joined by a rigid but adjustable st,eel wire, overlay the right and left buccal teeth. Self-curing acrylic resin placed in these troughs permitted individualized adaptation of the fixator to the dcntition of each subject. On the buccnl ‘Clark Electronics t(:rass Instrument, Preamnlifier.
Laboratory, Company,
Palm Springs, 101 Old Colony
Calif., Ave.,
No. VI 25 Microducer. Quincy, Mass., Model
5C
Polygraph,
5P
858
Engelman
I
LABIAL
ACRYLIC
FORCE
I
.040
LABIAL
LEAD WIRE
GAUGE
CARRIER Fig.
1. Int,rnoral
apparatus.
flange of the right trough was a vertical t.ubc which served as a hinged attachment for the labial bow of the apparatus. The labial bo~v consisted of an 0.040 inch steel wire with an acrylic plate, 2 by 39 by 6 mm., attached in its anterior area to lit between the incisor teeth and thr lip. The acrylic presented a larger surfacc area to the lip and allowed greater comfort. Pressure from the lip moved the labial bar posteriorly. The left end of the labial bow wire extended through a horizontal guide tube on the buccal flange of the left trough and terminated against the center of the transducer disk. This disk was attached to a vertical plate extending buccally perpendicular to the flange. The transducer was insulated from moisture by a coating of epoxy enamel.’ Wire leads from the terminal plat,es of the microducer were connect,ed extraorally to a,n adaptor circuit box which was, in turn, plugged into the preamplifier of the polygraph. The labial bow moved posteriorly as a result o-f lip pressure against the acrylic shield, and this caused the end of the wire to press against the transducer, altering its resistance. The resultant change in voltage caused a deflection of the oscillograph pen on the chart paper of the polygraph. The deflection could be expressed in units of force by reference to a calibration curve. Twenty subjects, ranging in age from IO to 17 years, were included in this study. They were patients in the Department of Orthodontics at Washington University School of Dentistry who had not begun treatment or were not in a period of active orthodontic therapy. Each subject had at least one year’s experience with the musical instrument used during the recording. In each subject, the intraoral apparatus was positioned securely by means of individual acrylic impressions formed in metal troughs in such a. manner that the acrylic plate was 1 to 2 mm. away from the incisors in the pa.ssive state (Fig. 2). *Glidden
Paint
Company,
106 Gratiot
St., St. Louis,
MO.,
508 white
epoxy
enamel
and converter.
Perioral
Fig.
2. Photograph
of
int,raoral
pressures and nausicul
fixator-carrier
with
labial
how
wind inshrurnents
859
attached.
In order that the perioral pressures might be evaluated, the following set of exercises was executed: 1. Maximum pressure. The subject was instructed to pull the lip down as far as possible. 2. Swallowing. The subject swallowed a sip of water. 3. Thumb-sucking. The subject was directed to suck his thumb, without any particular instruction as to method. 4. Whistling. The subject whistled a prescribed tune. 5. Instrument C-major scale. The subject played the C-major scale on his own instrument. The apparatus was permitted to remain in the mouth for a,pproximately 15 minutes before a recording was made in order that the subject might become accustomed to it and so that the transducer could reach mouth temperature. Each of the exercises was performed three times. Five seconds was allowed for each trial, with a rest interval of 15 seconds between trials. All recordings were made at a polygraph sensitivity of 0.5 mv. per centimeter and at a chart speed of 0.5 mm. per second. By referring to a transducer calibration curve, it was possible t,o transform millimeters of pen deflection, as recorded on the chart paper, to grams of force. RESULTS
In order to standardize the apparat,us, a calibration curve was obtained by adapting the apparatus to a dental cast. Known weights of from 150 to 1,685 grams were applied to the acrylic portion of the labial bar, and the deflection of the oscillograph pen was recorded on chart paper. Calibration curves were obtained on seven occasions to determine the reproducibility of the apparatus. A linear response of the apparatus was noted over the pressure range used. The mean values of the seven tests were used in computing a regression line which was employed in converting millimeters of pen deflect,ion to grams of force. 9 sample record illustrating t,he responses of a typical subject to the various test exercises is shown in Fig. 3. To determine the reliability of the recording technique, the first five subjects were tested on three separate occasions. From these triple determinations, the
860
Fig. per
Engelman
3. Sample second.
oscillograph
rrc~ord.
Sensitik-ity
: 0.5
nlv.
per
wntimetw.
Spw(l:
0.5
m1n.
Table I. Summary of d&a for totul group and for subjects g~wuped accordin~~ to instrument played Maximum musde pressure (Gm.) Group mean s. D. Brass group mean + S. Reed group mean + S. Flute group mean ? S.
Thumb-sucking (Gm.)
Whistling (Gm.)
/
Instrument C-major scale (Gm.)
5 “93
51 174
D.
500
+ 67
D.
270
2 86
D.
211
+ 150
397
+ 196
315
2 178
215
+_ 169
maximum deviation from the mean value of each exercise was expressed as a per cent of the mean values (per cent maximum deviation). Computation of these values revealed 10.5 per cent maximum deviation for the maximum pressure exercise, 18.0 per cent for thumb-sucking, 34.7 per cent for the whistling exercise, and 18.8 per cent for the instrument exercise. The group mean, standard dcviat,ion, and a summary of data derived from the sample of twenty subjects are presented in Table I. Swallowing pressure was not of sufficient magnitude to produce a measurable pen deflection; therefore, this exercise was considered no further in the study. The subjects were classified into three subgroups accordin, w to type of instrument played, and the mean values for instrument pressure were computed for each subgroup. To test the null hypothesis that there is no difference in the pressure exerted by various classes of instruments, t,he Student’s “t” test was used to test for significant differences between the means for subject,s who played instruments of the cup-shaped (brass), reed, and flute categories. The brass group showed
Perimd
pressures and musica.1 wind instmments
86 1
means that were significantly r greater than t,hose shown by either the reed or the flute group. To ascertain any relationship between the maximum pressure and the various exercises and between the maximum pressure and instrument pressure for the individual subgroups, the correlation coefficient (“r” values) were computed and “t” tests were determined to show their significance. The only high correlation significant at the 5 per cent level was between maximum pressure and flute instrument pressure. DISCUSSIOS
External pressures acting on the dentition can change tooth position. The effect of musical wind instruments on the dentition warrants investigation, since the forces produced by them may be of sufficient magnitude, duration, and direction to help produce a malocclusion or, conceivably, to help correct one. The knowledge that one type of instrument creates a consistently higher pressure t,han another in a given direction may aid in the selection of an instrument that would be most, desirable for the young musician from the dental and orthodontic standpoints. With this in mind, the pressure exerted on the maxillary incisors during the playing of wind instruments was examined and compared to pressures exerted by perioral musculature during various prescribed exercises. The exercise capable of producing maximum pressure establishes the greatest force that a subject is able to produce with the lips. Swallowing demonstrates pressures repeatedly exerted by the lips in normal contraction, thumb-sucking demonst,rates the force produced by abnormal compression of the lips, and whistling represents an average pressure force. Because of their placement between or on the lips, musical instruments, act as extraoral forces together with the lingually directed force of the lips. An examination of the means of the various exercises shows that the mean maximum muscle pressure and thumb-sucking pressure are the highest in grams of force. The mean pressure of the whistling exercise is the lowest of all exercises (except swallowing, which was found to be so small as to produce no measurable pressure). Instrument pressure is greater than whistling but less than the maximum-effort and thumb-sucking pressures. The forces produced by the musical instruments are larger than forces produced by average muscle contraction and approach pressure levels associated with maximum lip-muscle effort. This gives credence to the belief that, instrument pressure should be given consideration in orthodontic rationale. Maximum pressure showed no significant correlation with any of the other exercise pressures. The values obtained appear related more to the particular manner in which the exercise was performed than to any inherent strength of t,he lip musculature. The possibility that different types of musical instrument produce varying compression of the lips was investigated. The various instruments were separated into three subgroups-brass, reed, and flute. An examination of the brass subgroup showed its mean instrument pressure to be higher than the group mean of maximum muscle pressure. The young amateur musicians who participated
862
Engelman
in this study tended to use the pressure system of embouchure, that is, a pressing backward of the instrument against the lips. For this reason, the pressure for the brass subgroup mean was higher than the pressure produced 1)~ the reetl and flute subgroups. In this regard, brass inst,rumrnts should be given consideration in the management of maxillary dental protrusions. The mean instrument pressures for the reed and flute subgroups were Neal the group mean for whistling, an exercise that can be considered a normal COW traction. The flute and reed means are considerably smaller than the mean of the brass subgroup, indicating that, these instrmncnts would have less infincnett in a posterior direction on the dentition. In order to test the null hypothesis that, the pressure of the brass instrument is no different than that of the reed and flute, “t” tests were computed. These were significant at a 5 per cent level. The “t!’ test comparing the reed to flute group is not significant. This might be oxpccted, since the muscle activity illvolved in playing these instruments is somewhat similar and the nronthpiece produces no extraoral force against the incisors. To investigate the relat,ionship between maximum muscle pressure and instrument pressure, a correlation coefficient was computed between t,hcse values for the total group. This correlation was follnd to he insignificant, and one could conclude that generally the maximum pressure that a subject could exert had no relationship to t,hc pressure prodncc~l when IIC played a musical wind instrument. When the relationship was compntcd for ~~11 of the instrument subgroups, however, a significant correlation was found between maximurn pressure and instrument pressure in the flute subgroup. To account for the existence of this relationship in only this one area, reference cm bc made to the effect of playing the flute on the development of lip musculature. StraJ-er’ has asserted that, (“lass 1) instrument,s (which would include the flllte and piccolo) are effcctivc in improving muscle tone and post,urc ot’ tlic lips. A relative comparison oi’ the values of maximum prcssurc and swallow-in g shows agreement, with t tie firitlings reported by M’inders,24-“’ since both arc high and low, respectivcll\-. in each study. CON01
, USIONS
1jroduced the highest, pressures 1. Maximum pressure and thumb-sucking of thr exercises measured, and swallowing and whistling produced the lowest. The group mean for inst,rument pressure lay between these values. 2. Brass instruments produced significantly greater lingually dirrct~ed pressure against the incisors than any other instruments. 3. Jnst,rument pressure values wcrc not significant1.v correlated with maximum pressure values except in the case of the flute players, suggesting that, there is a relat.ionship between flute playin g and increased tone of the upp~ lip.
The forces produced against the labial surfaces of the maxillary incisors during the playing of various types of musical wind instruments were measured pressure was in twenty subjects by means of a transducer. This instrument
compared to pressures produced b;v the pcrioral muscles during the execution of prescribed cscrcises (maximum pressure, swallowing, whistling, and thumbsucking). REFERENCES 1. Strayer, E. R.: Musical Instruments as an Aid in the Treatment of Muscle 1)efects ant1 Perversions, Angle Orthodontist 9: X3-27, 1939. 2. Schultz, Stephen: Wind Instruments and the Dental Problem, J. 11Tisconsin I). SOC. 33: 239-242 262 1962. 3. Hruby, A., and Kessler, H. E.: Dentistry and Musical Wind Instrument Problem, I). Radiog. & Photog. 32: l-8, 1959. 4. Kessler, H. E.: Study of the Dental Factors Concerned With Playing a Musical Wintl Instrument, D. Students’ Mag. 37: 22-25, 1959. 5. Kessler, H. E.: Dental Study of a Professional Trumpet Player, J. Am. Dent. A. 59: 320-321, 1959. 6. Kessler, H. I’:.: Particular Dental Care for Musicians, Oral Hyg. 49: 48-49, 1959. 7. Frank, B.: Orthodontics for Better Looks, for Better Speech, for Better Music (Abst.), Internat. D. J. 7: 505, 1957. 8. Heskia, J. E., and Hospital, I,.: Musical 1Vind Instruments Utilized in Orthodontics, D. Abst. 2: 67, 1957. 9. Seidner, S.: Importance of the I)ental Conditions for Players of Wind Instruments, I). Abst. 2: 68-69, 1957. IO. Reitlner, H.: Can Orthodontic Treatment Be influenced by Wind Jnstruments? .I. 1Visconsin 1). Sot. 40: 261-263, 1964. 11. Clleyncy, E. A.: Adaptation to Embouchure as a Function of Dentofacial Complex, A>v. J. ORTIIOIMNTICB 35: 440, 1949. 12. ‘l’ulley, W. J. : Adverse Muscle Forces; Their Diagnostic Significance, AM. J. ORTHOl)ONTI(‘S 42: 801-814, 1956. 13. Porter, M. M.: Dental Factors Adversely Influencing the Playing of Wind Instruments; the Role of Artificial Aids, Brit. I>. J. 95: 152-160, 1953. l-4. Rogers, A. I’.: Muscle Training in Relation to Orthodontics, INT. J. ORTH~WNTIA 4: 555-577, 1918. 15. Rogers, A. P.: The Placement of Myofunctional Treatment in the Correction of Malocclusion, J. Am. Dent. A. 23: 6678, 1936. 16. Rogers, A. P.: The Nonmechanical Treatment of Dentofacial Deformities, J. Am. Dent. .4. 15: 290.294, 1928. 17. dlderisio, J. P.: An Electronic Technique for Recording the Myodynamic Forces of the Lip, Cheek, and Tongue, J. D. Res. 32: 548.553, 1953. 1% Margolis, H. I., and Prakash, P.: A I\;ew Instrument for Recording Oral Muscle Forces; the Photoelectric Npodynograph, J. I). Res. 33: 425-435, 1954. 19. Fcldstein, L. : An Instrument for Measuring Muscular Forces Acting on the Teeth, Xar. J. 0KTHOl)ONTICS 36: 856.859, 1950. 20. Kydd, William J.: Maximum Forces Exerted on the Dentition by the Perioral and Lingual Musculature, J. Am. Dent. A. 55: 646.651, 1957. 01. Kydd, William J., Akamine, .J. S., Mendel, R. A., and Kraus, B. S.: Tongue and I,ip l’orces Exerted During Deglutition in Subjects With and Without an Open Bite, J. I). Res. 42: 858-866, 1963. 22. Stevens, Huey M.: The intraoral Pressure Exerted on the Maxillary and Mandibular Central Incisors by the Tongue and TJips in Angle Class Tl, Division 1 Cases (Al)&), AM.
23.
24.
J. ORTHODONTICS
42:
937,
1956.
Sims, F. W.: Pressure Exerted on the Maxillary and Mandibular Incisors by the Perioral and Lingual Musculature in Awcptahle Occlusions (Abst.), AM. J. ORTII~UO~VI’ICS 44: 64-65 1958. Winders, Rolwt V.‘: A Study in the Development of an Electronic Technique to Measure
25. 26. 27.
28. 29.
the Forces Exerted on the Dentition l)y tho Perioral and Lingual Mu.vulature, AX J. ORTHOI)OA-TICS 42: 645.657, 1956. Winders, Robert V.: Forces Exerted on the Dentition by the Perioral ant1 I,ingual Musculature During Swallowing, Angle Orthodontist 28: 236-251, 19.58. Winders, Robert V.: Recent Findings in Myometric Research, Sngle Orthodontist 32: 35-43, 196”. Bovet, .J. M., Ketter, S., and Sasaki, II.: Ilirect 1Ieasuremeut of the Tbnto =\lveolar Equilibrium by Extensiometer Gauges. In Tylman. 8. I)., and others (editors): Year Book of Dentistry (1962.1963), Chicago, 1963, Year Hook Medical Publishers, pp. “li-219. Proffet, William R., Kydd, William L., XVilskie, G., and Taylor, I).: Intraoral Pressures in a Young Adult Group, J. J). Res. 43: 555562, 1964. Pa,rkcr, .Tohn H.: The Alameda Instrumental Study, AM. J. ORTIIODONTICS 43: X&-116, 1!)57.
IS well known that biologic changes occur in the t,issucs surrounding the root of the tooth when extraneous forces arc applied to the crown. Rrsorption and deposition of bone, as well as fibrillar reorientation within the periodontal ligament, permit alteration in the position ol’ a tooth when prolonged forces arc applied. Embouchure, the manner of applying the lips and teeth to the mouthpiece of a musical wind instrument, may produce sufficient pressure on the teeth to cause tooth movement. This study was initiated to measure and evaluate the amount of pressure exerted by the upper lip against. the maxillary anteriol teeth of various musicians playing different instrumrnts. In 1939, Strayer1 classified instruments according to type 01 monthpiecc: and rccommcnded that, specific instrmricnts bc selcctcd for their bcricficial influencc on esisting malocclusion. Schultz,” I lrubp and Kessler,:’ Kessler,+‘; Frank.’ and IIeskia and Hospitals hale made similar suggestions. On the other hand, musical instruments may be chosen to fit the prevailing malocclusion from the ease-of-playing standpoint, without regard to anp detrimental influence that may bc cscrtcd on the dentition.+” The significance of circumoral muscle influence has been mentioned. Tulley\-l’ theorized from electromyographic observation that a lip cont,raction greater than the pressures exerted by the tongue caused retroinclination of the incisors. Portcr’sl” studies supported the theory that forces resultZing from the playing of musical instruments affect. the dentit,ion. Rogers I-~-Mclinically demonstrated the place of myofunctional therapy in corrcctin, 0‘ malocclusion and in aiding normal development of the dentofacial complex. Strengthening of the pcrioral musculature by playin, 0‘ a musical instrument may aid in maintaining a normal occlusion following orthodontic correction. A numhcr of research studies hare IT
856
Perioral
pressures a.7ld musical wind instruments
857
been directed toward assessment of the balance between lip and tongue forces.17-28 Generally, the investigators concluded that the tongue is capable of producing a greater maximum muscle force than the lips. Of the various devices used to measure muscle pressures, the most accurate have been the electronic strain gauges. WinderP” attached gauges to the labial surface of a maxillary incisor and measured the maximum pressure, resting pressure, and swallowing pressure of the perioral musculature. He established this method as a reliable means of recording labial forces. In contrast to the opinions just mentioned, the Alameda Instrument Study demonstrated that the playing of musical instruments or the type of instrument played had little effect on tooth position, provided the patient was using correct embouchure and was under proper supervision.‘” In the present study an attempt has been made to answer the following questions: What is the magnitude of the perioral force involved in playing a musical wind instrument? And what is the variation of this force from subject to subject? What is the relationship between instrumental pressure and other pcrioral forces? No previous study has attempted to measure the forces produced by musical instruments. METHODS
ASD
MATERIALS
In order to measure the lingually directed force of the upper lip against the maxillary incisors during the playing of a musical instrument, an intraoral pressure transducer was designed to meet the following requirements : (1) sufficiently small bulk so as not to interfere with playing of the instrument; (2) sensitivity over a range consistent with the pressures to be measured; (3) adaptability to various subjects; and (4) accurate repositioning in a given subject,. The pressure-sensitive element of the device constructed for this study was a transducer,* consisting of a wafer 6 mm. in diameter and 1.5 mm. thick. The clement, was made of two brass terminal plates between which was a layer of pressure-sensitive paint composed of rare-earth materials. The pressure transducer had a minimum resistance of 1,000 ohms and a pressure range of from 0 to 2.5 pounds. This transducer, because of the properties of the rare earths, exhibited a decrease in electrical resistance as pressure against it increased. The resultant change in voltage was amplified and recorded by means of a preamplifier and an ink-writing oscillograph.+ The intraoral apparatus consisted of a fixator-carrier by means of which the apparatus was retained and stabilized against the maxillary dentition and transmitted pressure to the transducer element (Fig. I). Two rectangular metal t.roughs, joined by a rigid but adjustable st,eel wire, overlay the right and left buccal teeth. Self-curing acrylic resin placed in these troughs permitted individualized adaptation of the fixator to the dcntition of each subject. On the buccnl ‘Clark Electronics t(:rass Instrument, Preamnlifier.
Laboratory, Company,
Palm Springs, 101 Old Colony
Calif., Ave.,
No. VI 25 Microducer. Quincy, Mass., Model
5C
Polygraph,
5P
858
Engelman
I
LABIAL
ACRYLIC
FORCE
I
.040
LABIAL
LEAD WIRE
GAUGE
CARRIER Fig.
1. Int,rnoral
apparatus.
flange of the right trough was a vertical t.ubc which served as a hinged attachment for the labial bow of the apparatus. The labial bo~v consisted of an 0.040 inch steel wire with an acrylic plate, 2 by 39 by 6 mm., attached in its anterior area to lit between the incisor teeth and thr lip. The acrylic presented a larger surfacc area to the lip and allowed greater comfort. Pressure from the lip moved the labial bar posteriorly. The left end of the labial bow wire extended through a horizontal guide tube on the buccal flange of the left trough and terminated against the center of the transducer disk. This disk was attached to a vertical plate extending buccally perpendicular to the flange. The transducer was insulated from moisture by a coating of epoxy enamel.’ Wire leads from the terminal plat,es of the microducer were connect,ed extraorally to a,n adaptor circuit box which was, in turn, plugged into the preamplifier of the polygraph. The labial bow moved posteriorly as a result o-f lip pressure against the acrylic shield, and this caused the end of the wire to press against the transducer, altering its resistance. The resultant change in voltage caused a deflection of the oscillograph pen on the chart paper of the polygraph. The deflection could be expressed in units of force by reference to a calibration curve. Twenty subjects, ranging in age from IO to 17 years, were included in this study. They were patients in the Department of Orthodontics at Washington University School of Dentistry who had not begun treatment or were not in a period of active orthodontic therapy. Each subject had at least one year’s experience with the musical instrument used during the recording. In each subject, the intraoral apparatus was positioned securely by means of individual acrylic impressions formed in metal troughs in such a. manner that the acrylic plate was 1 to 2 mm. away from the incisors in the pa.ssive state (Fig. 2). *Glidden
Paint
Company,
106 Gratiot
St., St. Louis,
MO.,
508 white
epoxy
enamel
and converter.
Perioral
Fig.
2. Photograph
of
int,raoral
pressures and nausicul
fixator-carrier
with
labial
how
wind inshrurnents
859
attached.
In order that the perioral pressures might be evaluated, the following set of exercises was executed: 1. Maximum pressure. The subject was instructed to pull the lip down as far as possible. 2. Swallowing. The subject swallowed a sip of water. 3. Thumb-sucking. The subject was directed to suck his thumb, without any particular instruction as to method. 4. Whistling. The subject whistled a prescribed tune. 5. Instrument C-major scale. The subject played the C-major scale on his own instrument. The apparatus was permitted to remain in the mouth for a,pproximately 15 minutes before a recording was made in order that the subject might become accustomed to it and so that the transducer could reach mouth temperature. Each of the exercises was performed three times. Five seconds was allowed for each trial, with a rest interval of 15 seconds between trials. All recordings were made at a polygraph sensitivity of 0.5 mv. per centimeter and at a chart speed of 0.5 mm. per second. By referring to a transducer calibration curve, it was possible t,o transform millimeters of pen deflection, as recorded on the chart paper, to grams of force. RESULTS
In order to standardize the apparat,us, a calibration curve was obtained by adapting the apparatus to a dental cast. Known weights of from 150 to 1,685 grams were applied to the acrylic portion of the labial bar, and the deflection of the oscillograph pen was recorded on chart paper. Calibration curves were obtained on seven occasions to determine the reproducibility of the apparatus. A linear response of the apparatus was noted over the pressure range used. The mean values of the seven tests were used in computing a regression line which was employed in converting millimeters of pen deflect,ion to grams of force. 9 sample record illustrating t,he responses of a typical subject to the various test exercises is shown in Fig. 3. To determine the reliability of the recording technique, the first five subjects were tested on three separate occasions. From these triple determinations, the
860
Fig. per
Engelman
3. Sample second.
oscillograph
rrc~ord.
Sensitik-ity
: 0.5
nlv.
per
wntimetw.
Spw(l:
0.5
m1n.
Table I. Summary of d&a for totul group and for subjects g~wuped accordin~~ to instrument played Maximum musde pressure (Gm.) Group mean s. D. Brass group mean + S. Reed group mean + S. Flute group mean ? S.
Thumb-sucking (Gm.)
Whistling (Gm.)
/
Instrument C-major scale (Gm.)
5 “93
51 174
D.
500
+ 67
D.
270
2 86
D.
211
+ 150
397
+ 196
315
2 178
215
+_ 169
maximum deviation from the mean value of each exercise was expressed as a per cent of the mean values (per cent maximum deviation). Computation of these values revealed 10.5 per cent maximum deviation for the maximum pressure exercise, 18.0 per cent for thumb-sucking, 34.7 per cent for the whistling exercise, and 18.8 per cent for the instrument exercise. The group mean, standard dcviat,ion, and a summary of data derived from the sample of twenty subjects are presented in Table I. Swallowing pressure was not of sufficient magnitude to produce a measurable pen deflection; therefore, this exercise was considered no further in the study. The subjects were classified into three subgroups accordin, w to type of instrument played, and the mean values for instrument pressure were computed for each subgroup. To test the null hypothesis that there is no difference in the pressure exerted by various classes of instruments, t,he Student’s “t” test was used to test for significant differences between the means for subject,s who played instruments of the cup-shaped (brass), reed, and flute categories. The brass group showed
Perimd
pressures and musica.1 wind instmments
86 1
means that were significantly r greater than t,hose shown by either the reed or the flute group. To ascertain any relationship between the maximum pressure and the various exercises and between the maximum pressure and instrument pressure for the individual subgroups, the correlation coefficient (“r” values) were computed and “t” tests were determined to show their significance. The only high correlation significant at the 5 per cent level was between maximum pressure and flute instrument pressure. DISCUSSIOS
External pressures acting on the dentition can change tooth position. The effect of musical wind instruments on the dentition warrants investigation, since the forces produced by them may be of sufficient magnitude, duration, and direction to help produce a malocclusion or, conceivably, to help correct one. The knowledge that one type of instrument creates a consistently higher pressure t,han another in a given direction may aid in the selection of an instrument that would be most, desirable for the young musician from the dental and orthodontic standpoints. With this in mind, the pressure exerted on the maxillary incisors during the playing of wind instruments was examined and compared to pressures exerted by perioral musculature during various prescribed exercises. The exercise capable of producing maximum pressure establishes the greatest force that a subject is able to produce with the lips. Swallowing demonstrates pressures repeatedly exerted by the lips in normal contraction, thumb-sucking demonst,rates the force produced by abnormal compression of the lips, and whistling represents an average pressure force. Because of their placement between or on the lips, musical instruments, act as extraoral forces together with the lingually directed force of the lips. An examination of the means of the various exercises shows that the mean maximum muscle pressure and thumb-sucking pressure are the highest in grams of force. The mean pressure of the whistling exercise is the lowest of all exercises (except swallowing, which was found to be so small as to produce no measurable pressure). Instrument pressure is greater than whistling but less than the maximum-effort and thumb-sucking pressures. The forces produced by the musical instruments are larger than forces produced by average muscle contraction and approach pressure levels associated with maximum lip-muscle effort. This gives credence to the belief that, instrument pressure should be given consideration in orthodontic rationale. Maximum pressure showed no significant correlation with any of the other exercise pressures. The values obtained appear related more to the particular manner in which the exercise was performed than to any inherent strength of t,he lip musculature. The possibility that different types of musical instrument produce varying compression of the lips was investigated. The various instruments were separated into three subgroups-brass, reed, and flute. An examination of the brass subgroup showed its mean instrument pressure to be higher than the group mean of maximum muscle pressure. The young amateur musicians who participated
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in this study tended to use the pressure system of embouchure, that is, a pressing backward of the instrument against the lips. For this reason, the pressure for the brass subgroup mean was higher than the pressure produced 1)~ the reetl and flute subgroups. In this regard, brass inst,rumrnts should be given consideration in the management of maxillary dental protrusions. The mean instrument pressures for the reed and flute subgroups were Neal the group mean for whistling, an exercise that can be considered a normal COW traction. The flute and reed means are considerably smaller than the mean of the brass subgroup, indicating that, these instrmncnts would have less infincnett in a posterior direction on the dentition. In order to test the null hypothesis that, the pressure of the brass instrument is no different than that of the reed and flute, “t” tests were computed. These were significant at a 5 per cent level. The “t!’ test comparing the reed to flute group is not significant. This might be oxpccted, since the muscle activity illvolved in playing these instruments is somewhat similar and the nronthpiece produces no extraoral force against the incisors. To investigate the relat,ionship between maximum muscle pressure and instrument pressure, a correlation coefficient was computed between t,hcse values for the total group. This correlation was follnd to he insignificant, and one could conclude that generally the maximum pressure that a subject could exert had no relationship to t,hc pressure prodncc~l when IIC played a musical wind instrument. When the relationship was compntcd for ~~11 of the instrument subgroups, however, a significant correlation was found between maximurn pressure and instrument pressure in the flute subgroup. To account for the existence of this relationship in only this one area, reference cm bc made to the effect of playing the flute on the development of lip musculature. StraJ-er’ has asserted that, (“lass 1) instrument,s (which would include the flllte and piccolo) are effcctivc in improving muscle tone and post,urc ot’ tlic lips. A relative comparison oi’ the values of maximum prcssurc and swallow-in g shows agreement, with t tie firitlings reported by M’inders,24-“’ since both arc high and low, respectivcll\-. in each study. CON01
, USIONS
1jroduced the highest, pressures 1. Maximum pressure and thumb-sucking of thr exercises measured, and swallowing and whistling produced the lowest. The group mean for inst,rument pressure lay between these values. 2. Brass instruments produced significantly greater lingually dirrct~ed pressure against the incisors than any other instruments. 3. Jnst,rument pressure values wcrc not significant1.v correlated with maximum pressure values except in the case of the flute players, suggesting that, there is a relat.ionship between flute playin g and increased tone of the upp~ lip.
The forces produced against the labial surfaces of the maxillary incisors during the playing of various types of musical wind instruments were measured pressure was in twenty subjects by means of a transducer. This instrument
compared to pressures produced b;v the pcrioral muscles during the execution of prescribed cscrcises (maximum pressure, swallowing, whistling, and thumbsucking). REFERENCES 1. Strayer, E. R.: Musical Instruments as an Aid in the Treatment of Muscle 1)efects ant1 Perversions, Angle Orthodontist 9: X3-27, 1939. 2. Schultz, Stephen: Wind Instruments and the Dental Problem, J. 11Tisconsin I). SOC. 33: 239-242 262 1962. 3. Hruby, A., and Kessler, H. E.: Dentistry and Musical Wind Instrument Problem, I). Radiog. & Photog. 32: l-8, 1959. 4. Kessler, H. E.: Study of the Dental Factors Concerned With Playing a Musical Wintl Instrument, D. Students’ Mag. 37: 22-25, 1959. 5. Kessler, H. E.: Dental Study of a Professional Trumpet Player, J. Am. Dent. A. 59: 320-321, 1959. 6. Kessler, H. I’:.: Particular Dental Care for Musicians, Oral Hyg. 49: 48-49, 1959. 7. Frank, B.: Orthodontics for Better Looks, for Better Speech, for Better Music (Abst.), Internat. D. J. 7: 505, 1957. 8. Heskia, J. E., and Hospital, I,.: Musical 1Vind Instruments Utilized in Orthodontics, D. Abst. 2: 67, 1957. 9. Seidner, S.: Importance of the I)ental Conditions for Players of Wind Instruments, I). Abst. 2: 68-69, 1957. IO. Reitlner, H.: Can Orthodontic Treatment Be influenced by Wind Jnstruments? .I. 1Visconsin 1). Sot. 40: 261-263, 1964. 11. Clleyncy, E. A.: Adaptation to Embouchure as a Function of Dentofacial Complex, A>v. J. ORTIIOIMNTICB 35: 440, 1949. 12. ‘l’ulley, W. J. : Adverse Muscle Forces; Their Diagnostic Significance, AM. J. ORTHOl)ONTI(‘S 42: 801-814, 1956. 13. Porter, M. M.: Dental Factors Adversely Influencing the Playing of Wind Instruments; the Role of Artificial Aids, Brit. I>. J. 95: 152-160, 1953. l-4. Rogers, A. I’.: Muscle Training in Relation to Orthodontics, INT. J. ORTH~WNTIA 4: 555-577, 1918. 15. Rogers, A. P.: The Placement of Myofunctional Treatment in the Correction of Malocclusion, J. Am. Dent. A. 23: 6678, 1936. 16. Rogers, A. P.: The Nonmechanical Treatment of Dentofacial Deformities, J. Am. Dent. .4. 15: 290.294, 1928. 17. dlderisio, J. P.: An Electronic Technique for Recording the Myodynamic Forces of the Lip, Cheek, and Tongue, J. D. Res. 32: 548.553, 1953. 1% Margolis, H. I., and Prakash, P.: A I\;ew Instrument for Recording Oral Muscle Forces; the Photoelectric Npodynograph, J. I). Res. 33: 425-435, 1954. 19. Fcldstein, L. : An Instrument for Measuring Muscular Forces Acting on the Teeth, Xar. J. 0KTHOl)ONTICS 36: 856.859, 1950. 20. Kydd, William J.: Maximum Forces Exerted on the Dentition by the Perioral and Lingual Musculature, J. Am. Dent. A. 55: 646.651, 1957. 01. Kydd, William J., Akamine, .J. S., Mendel, R. A., and Kraus, B. S.: Tongue and I,ip l’orces Exerted During Deglutition in Subjects With and Without an Open Bite, J. I). Res. 42: 858-866, 1963. 22. Stevens, Huey M.: The intraoral Pressure Exerted on the Maxillary and Mandibular Central Incisors by the Tongue and TJips in Angle Class Tl, Division 1 Cases (Al)&), AM.
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Sims, F. W.: Pressure Exerted on the Maxillary and Mandibular Incisors by the Perioral and Lingual Musculature in Awcptahle Occlusions (Abst.), AM. J. ORTII~UO~VI’ICS 44: 64-65 1958. Winders, Rolwt V.‘: A Study in the Development of an Electronic Technique to Measure
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the Forces Exerted on the Dentition l)y tho Perioral and Lingual Mu.vulature, AX J. ORTHOI)OA-TICS 42: 645.657, 1956. Winders, Robert V.: Forces Exerted on the Dentition by the Perioral ant1 I,ingual Musculature During Swallowing, Angle Orthodontist 28: 236-251, 19.58. Winders, Robert V.: Recent Findings in Myometric Research, Sngle Orthodontist 32: 35-43, 196”. Bovet, .J. M., Ketter, S., and Sasaki, II.: Ilirect 1Ieasuremeut of the Tbnto =\lveolar Equilibrium by Extensiometer Gauges. In Tylman. 8. I)., and others (editors): Year Book of Dentistry (1962.1963), Chicago, 1963, Year Hook Medical Publishers, pp. “li-219. Proffet, William R., Kydd, William L., XVilskie, G., and Taylor, I).: Intraoral Pressures in a Young Adult Group, J. J). Res. 43: 555562, 1964. Pa,rkcr, .Tohn H.: The Alameda Instrumental Study, AM. J. ORTIIODONTICS 43: X&-116, 1!)57.