tongue movements in patients with skeletal class ii malocclusion evaluated with real-time balanced...

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Tongue movements in patients with skeletal ClassII malocclusion evaluated with real-time balancedturbo field echo cine magnetic resonance imaging

Fatih Yılmaz,a Deniz Sa�gdıc,b Seniz Karacay,c Erol Akin,d and Nail Bulakbasıe

Ankara and Istanbul, Turkey

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Introduction: The aim of this study was to evaluate the deglutitive tongue movements in patients with skeletalClass II malocclusion.Methods: Fifty-nine patients (26 male, 33 female) with skeletal Class II relationship weredivided into 3 groups according to cephalometric analysis. Group 1 (n 5 19) had mandibular retrognathism,group 2 (n5 20) had maxillary prognathism, and group 3 (n5 20) had both mandibular retrognathism and max-illary prognathism. Twenty-two skeletal Class I patients (10 male, 12 female) were also included as the controls.Results: In the mandibular retrusion group, the posterior portion of the dorsal tongue moved downward at stage2 and upward at stage 3; the root of the dorsal tongue was in an inferior and anterior position at stage 2. In pa-tients with bothmandibular retrognathism andmaxillary prognathism, themiddle portion of the dorsal tonguewaspositioned superiorly at stage 3 relative to stage 1; the tongue tip was retruded at stage 3 relative to stages 1 and2. In the control group, the middle portion of dorsal tongue was positioned superiorly at stage 3 relative to stages1 and 2; the posterior portion of the tongue moved upward at stage 2 and downward at stage 3, and tongue-tipretrusion was observed at stage 2 relative to stage 1. Contact of the anterior portion of the tongue with the rugaearea of the hard palate decreased in the Class II malocclusion groups relative to the control group. The middleportion of the dorsal tongue was positioned more superiorly in patients with Class II malocclusion during allstages of deglutition. The root of the tongue was more inferior and anterior, and the tongue tip was retrudedin patients with Class II malocclusion compared with the control group. The posterior portion of the dorsaltongue was more inferiorly positioned in patients with mandibular retrusion than in the other Class II groupsor the controls. In the third stage of deglutition, this portion of the tongue had a superior position in groups 2and 3 relative to the control group. Conclusions: Dentofacial morphology affects the position and movementsof the tongue during deglutition, and adaptive changes occur in the tip, dorsum, and root of the tongue. Deglu-titive tongue movements in patients with a skeletal Class II relationship are different from those with a skeletalClass I relationship. (Am J Orthod Dentofacial Orthop 2011;139:e415-e425)

The development of an occlusion is the result of theinteractions among the genetically developmentalfactors and a number of environmental factors, in-

cluding the orofacial functions.1 The environment of the

ciate professor, Department of Orthodontics, Center of Dental Sciences,ne Military Medical Academy, Ankara, Turkey.ssor, Department of Orthodontics, Center of Dental Sciences, Gulhanery Medical Academy, Ankara, Turkey.ciate professor, Dental Service, Haydarpasha Education Hospital, Gulhanery Medical Academy, Istanbul, Turkey.ciate professor, Medicana Dental Hospital, Istanbul, Turkey.ciate professor, Department of Radiology, Gulhane Military Medicalmy, Ankara, Turkey.uthors report no commercial, proprietary, or financial interest in thects or companies described in this article.t requests to: Seniz Karacay, Tıbbiye Caddesi, GATA Haydarpasa Egitimnesi, Dis Servisi, Ortodonti B€ol€um€u, _Istanbul, Turkey; e-mail, [email protected], November 2009; revised, January 2010; accepted, February 2010.5406/$36.00ight � 2011 by the American Association of Orthodontists..1016/j.ajodo.2010.02.031

teeth and alveolar bone includes conflicting forces andpressures, especially from muscular functions, which inpart determine tooth positions.1,2

The tongue is an organ that occupies a large portionof the oral cavity and performs complex movementsduring mastication, deglutition, and speech. It also playsimportant roles in the transport of bolus from the ante-rior oral cavity to the pharynx. There is debate over therole of the tongue in the development and morphologyof the dental arches and dentofacial forms.3-6 Manyinvestigators have tried to find the relationship betweensize, posture, and function of the tongue with thesurrounding oral cavity and dentofacial morphology.6-9

The frequency of swallowing, the magnitude of theforce exerted on the teeth, the counteraction of theseforces by other muscular structures such as lips, theresistance of dentoalveolar structures to displacement,and the resting posture of the tongue when no

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e416 Yılmaz et al

swallowing is occurring are the important factors thatmight affect the relationship between tongue functionand dentofacial form.9 Melsen et al,6 who evaluated therelationship between swallowing pattern and differentmalocclusion traits, reported that malocclusion frequencywas higher among children swallowing without toothcontact, and the malocclusion traits most affected bythe swallowing pattern were the sagittal discrepancies.They suggested 2 swallowing patterns and reported thata high position of the tongue favored spacing in the max-illa and increased overjet, whereas low tongue position fa-vored spacing in the mandible and decreased overjet,creating a Class III tendency.

In recent years, it has been suggested that there arecorrelations between deglutitive (swallowing) tonguemovements and certain features of maxillofacial mor-phology. Ichiada et al,10 who evaluated the relationshipbetween the lingual-palatal contact duration associatedwith swallowing and maxillofacial morphology, reportedthat the patients with prolonged contact had tendenciesfor inclination of the maxillary incisors toward the lip,opening of the mandibular and occlusal planes, and pos-terior rotation of the mandible. Cheng et al9 also showedsignificant correlations between the tongue movementsduring swallowing and dentofacial morphology. Theyreported that the movements of the tongue during swal-lowing are related to dentofacial morphology, especiallyin the motion magnitude of the early final phase. Fujikiet al11 showed that patients with open bite had tongue-tip protrusion, slower movement of the rear part of thedorsal tongue, and earlier closure of the nasopharynxduring deglutition. In their subsequent study, theyfound significant correlations between mandibularplane angle, ramus height, or anteroposterior dimensionof the maxilla and movement of the front part of thedorsal tongue during deglutition in the patients with an-terior open bite.12 Akin et al13 also reported compensa-tory tongue functions in patients with anterior openbites. Gorgulu et al,14 who evaluated the deglutitivetongue movements in patients with skeletal Class IIImalocclusion, reported a decreased contact of the an-terior portion of the tongue with the rugae area ofthe hard palate in those with Class III malocclusions.They also showed that the posterior portion of the dor-sal tongue was positioned more inferiorly, the root ofthe tongue was positioned more inferiorly and anteri-orly, and the tongue tip was also positioned more an-teriorly in patients with Class III malocclusions.Differences were also observed in the manner of bolustransfer. Linear motion of the tongue was observed inpatients with Class III malocclusion, whereas a fluctua-tion motion of the tongue occurred in patients withClass I malocclusion.14

May 2011 � Vol 139 � Issue 5 American

Asmentioned above, there have beenmany studies todetermine the relationship among oral structures, typesof malocclusion, and deglutition. These studies showedthat the characteristic tongue movements during deglu-tition were closely related to the morphologic features ofthe subjects. The purpose of our study was to investigatetongue posture and tongue movements during 3 stagesof deglutition in subjects with Class II malocclusion. Cin-ematic (cine) images of the tongue were obtained by us-ing real-time balanced turbo field echo cine-magneticresonance imaging (MRI), which was successfully usedin our previous studies to observe deglutitive tonguemovements.13-17 To our knowledge, this technique hasnot been used before in the evaluation of swallowingpatterns of patients with skeletal Class II malocclusion.

MATERIAL AND METHODS

This prospective study was carried out after institu-tional approval from the Ethics Committee of GulhaneMilitary Medical Academy in Ankara, Turkey.

Eighty-one patients (45 male, 36 female) were in-cluded in the study, and informed consents were ob-tained from all participants. They were divided into 4groups according to their skeletal relationships. Skeletalclassification was made by the evaluation of the sagittalcomponents of the jaws on the cephalometric radio-graphs, and it was based on the SNA, SNB, and ANBangles, and N vertical-A and N vertical-Pg linear mea-surements. Nineteen skeletal Class II patients (5 boys,14 girls; mean age, 14.056 1.87 years) with mandibularretrognathism (ANB, .4�; SNB, \78�; N vertical-Pg, \�6 mm) were included in the first group. In thesecond group, there were 20 skeletal Class II patients(9 boys, 11 girls; mean age, 14.20 6 1.39 years) withmaxillary prognathism (ANB, .4�; SNA, .84�; Nvertical-A,.2 mm). The third group comprised 20 skel-etal Class II patients (12 boys, 8 girls; mean age, 14.1562.05 years) with both mandibular retrognathism andmaxillary prognathism (ANB, .4�; SNA, .84�;SNB,\78�; N vertical-A, .2 mm; N vertical-Pg,\�6mm). Finally, 22 subjects (10 male, 12 female; meanage 18.266 5.22 years) with skeletal Class I relationship(ANB, 2� 6 2�; SNA, 82� 6 2�; SNB, 80� 6 2�; Nvertical-A, 06 1 mm; N vertical-Pg, �66 1 mm) com-posed the control group. The values of the measuredcephalometric parameters and the mean ages of thegroups are given in Table I.

All patients were examined with a 1.5-T super con-ducting magnetic resonance scanner with a quad H coiland version 9 software (New Intera Nova, Philips MedicalSystems, Best, The Netherlands). Real-time balancedturbo field echo images (shortest TR/TE:2.1/1.09 ms)

Journal of Orthodontics and Dentofacial Orthopedics

Table I. Mean ages of the groups and the measured cephalometric parameters

Mean age (y) SNA (�) SNB (�) ANB (�) N vertical-A (mm) N vertical-Pg (mm)

Mean SD Mean SD Mean SD Mean SD Mean SD Mean SDGroup 1 14.05 1.87 78.42 2.54 72.21 2.55 6.21 0.41 �4.18 2.46 �12.10 4.62Group 2 14.20 1.39 86.45 1.39 79.85 1.18 6.60 0.99 4.35 1.30 �5.00 1.62Group 3 14.15 2.05 84.45 0.99 76.70 1.45 7.75 1.25 3.30 1.08 �9.55 1.70All Class II groups 14.13 1.77 83.10 1.64 76.25 1.72 6.85 0.88 1.15 1.61 �8.88 2.64Group 4 18.26 5.22 81.27 1.01 79.36 1.12 1.91 0.83 0.10 1.30 �6.73 2.05

Fig 1. A, The oral stage begins when the contact of the tongue’s dorsum with the soft palate is lost (1).Tongue (white arrowhead), oropharynx (black arrow), and soft palate (white arrow) are shown. B, Thepharyngeal stage begins when the water head passes across the posterior or inferior margin of the ra-mus (2). Pharyngeal wall (thin, white arrowhead), closure of larynx (bold white arrow), elevation of hyoid(thin white arrow), and opening of esophagus (white triangle) are marked. C, The esophageal stagebegins when the water head passes through the opening of the esophagus (3). Opening of the upperesophageal sphincter is shown (white arrow).

Yılmaz et al e417

were taken with a 50� flip angle in the midsagittal plane,10 mm thickness, 350 3 350 mm field of view dimen-sions, and 963 96 matrix width during the patient’s wa-ter swallowing. A hundred dynamic scans were capturedin 11 seconds.

The images were obtained while the subjects wereswallowing 10 mL of water that was taken with a syringejust before imaging. For each patient, images matchingthe following 3 stages were determined by a consensusof 3 specialists and printed out on a radiograph: stage1 (oral): loss of contact of the dorsal tongue with thesoft palate (Fig 1, A); stage 2 (pharyngeal): passage ofthe bolus head across the posterior or inferior marginof the ramus of the mandible (Fig 1, B); and stage 3(esophageal): passage of the bolus head through theopening of the esophagus (Fig 1, C).

Linear measurements defined by Fujiki et al11 weremade on these radiographs for each stage by 1 author(F.Y.) to prevent interobserver variability. Reference

American Journal of Orthodontics and Dentofacial Orthoped

points and planes are shown in Table II. Since AM-Eand AM-PM are distances on the palatal mucosa, theywere curved lines. A ligature wire was used for themeasurement of these parameters. MM-MT, MM-MS,PM-PT, PM-PS, C1-D, C1-Me, and PS-I are straight dis-tances. P0-Ti is the shortest distance from a line crossingat a right angle to the NF plane through PNS to Ti (Fig 2).Magnetic resonance analyses of the groups arepresented in Table III.

The points and measurements of 25 patients werereevaluated 1 month later, and the method error wasdetermined by using Dahlberg’s formula: method

error 5ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiP

d2=2nq

, where n is the number of subjects

and d is the difference between the 2 measurements ofa pair.18 The method error did not exceed 0.135 mm.All statistical analyses of the groups were performedwith the Statistical Package for Social Sciences forWindows software (version 15, SPSS, Chicago, Ill). The

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Table II. Reference points and planes used in studyANS Most anterior point of the maxilla at the level of the palatePNS Most posterior point on the bony hard palateMe Lowest point on the symphyseal outline of the chinI Edge point of the maxillary incisorC1 Front-most point of the atlasNF Plane through both ANS and PNSSP Plane passing the edge of the maxillary incisor and parallel to the palatal planeAM Boundary point between the maxillary central incisor and the palatal mucosaE Point nearest the tongue base in the contact region between the tongue and the palatal mucosaMM Point at which the line crossing at a right angle to NF through the middle point between ANS and

PNS intersects the palatal mucosaMT Point at which the line crossing at a right angle to NF through the middle point between ANS and

PNS intersects the dorsum of the tongueMS Point at which the line crossing at a right angle to NF through the middle point between ANS and

PNS intersects SPPM Point at which the line crossing at a right angle to NF through PNS intersects the palatal mucosaPT Point at which the line crossing at a right angle to NF through PNS intersects the dorsum of tonguePS Point at which the line crossing at a right angle to NF through PNS intersects SPD Point at which the line through Me and C1 intersects the dorsum of the tongueTi Tongue tip

Fig 2. Linear measurements on MRI: (a), contact of tongue and palate (distances on the palatal mu-cosa) (AM-E/AM-PM); (b) middle portion of the dorsal tongue (straight distance) (MM-MT/MM-MS);(c) posterior portion of the dorsal tongue (straight distance) (PM-PT/PM-PS); (d) root of the dorsaltongue (straight distance) (C1-D/C1-Me); (e), tongue tip (shortest distance from the line crossing ata right angle to the NF plane through PNS to Ti) (P0-Ti/P0-I).11,12

e418 Yılmaz et al

differences between repeated measurements were evalu-ated by analysis of variance (ANOVA) for repeated mea-surements. Bonferroni tests were used as post-hoc tests.To analyze the differences within the groups, the pairedsample t test was used, and P#0.05 was accepted as thelevel of significant difference. In the comparison of theClass II groups with the control group, the Dunnetttest was used.

RESULTS

The stages were compared within the groups. In themandibular retrusion group (group 1) (Table IV), evalu-ation of the posterior portion of the dorsal tongue (PM-PT/PM-PS) showed a statistically significant increasebetween stages 1 and 2 (P\0.01) and a statistically sig-nificant decrease between stages 2 and 3 (P \0.01).


These alterations showed that this portion of the tonguemoved downward at stage 2 and upward at stage 3. Theroot of the dorsal tongue (C1-D/C1-Me) showed a signif-icant increase between stages 1 and 2 (P\0.05) becauseof the inferior and anterior position of the root of thetongue at stage 2 relative to stage 1.

Alterations in the contact of the anterior part of thetongue (AM-E/AM-PM) and the movements of the mid-dle portion of the dorsal tongue (MM-MT/MM-MS) andthe tongue tip (P0-Ti/P0-I) were statistically insignificant.

In the maxillary protrusion group (group 2) (Table V),no parameter showed a statistically significant alteration.

In the mandibular retrognathism and maxillary prog-nathism group (group 3) (Table VI), the distance betweenthe middle portion of the dorsal tongue and the palatalmucosa (MM-MT/MM-MS) was significantly smaller at


Table III. Magnetic resonance measurements of the groups

Group 1 Group 2 Group 3 Group 4

Mean (mm/mm) SD Mean (mm/mm) SD Mean (mm/mm) SD Mean (mm/mm) SDStage 1Anterior contact 0.158 0.155 0.095 0.082 0.095 0.055 0.266 0.057Middle part 0.365 0.188 0.301 0.169 0.358 0.147 0.607 0.157Posterior part 0.299 0.106 0.263 0.183 0.348 0.146 0.308 0.080Root of tongue 0.385 0.061 0.407 0.056 0.402 0.039 0.215 0.060Tip of tongue 0.708 0.139 0.775 0.127 0.675 0.207 0.945 0.120

Stage 2Anterior contact 0.123 0.136 0.078 0.063 0.137 0.141 0.297 0.070Middle part 0.337 0.153 0.222 0.106 0.323 0.184 0.663 0.153Posterior part 0.473 0.163 0.276 0.138 0.340 0.169 0.239 0.100Root of tongue 0.445 0.087 0.419 0.104 0.423 0.042 0.186 0.053Tip of tongue 0.780 0.142 0.753 0.197 0.755 0.094 0.850 0.125

Stage 3Anterior contact 0.086 0.039 0.084 0.062 0.081 0.045 0.271 0.051Middle part 0.275 0.092 0.227 0.140 0.225 0.073 0.403 0.219Posterior part 0.295 0.167 0.200 0.102 0.256 0.073 0.382 0.153Root of tongue 0.437 0.070 0.432 0.041 0.428 0.041 0.223 0.073Tip of tongue 0.773 0.077 0.773 0.068 0.799 0.093 0.904 0.147

Table IV. Comparison of the stages in group 1

Group 1 Stages

Meandifference(mm/mm) SD P

Anterior contact 1-2 0.035 0.039 1.0001-3 0.072 0.039 0.2162-3 0.037 0.039 1.000

Middle part 1-2 0.028 0.049 1.0001-3 0.089 0.049 0.2142-3 0.062 0.049 0.632

Posterior part 1-2 �0.174 0.048 0.002y

1-3 0.004 0.048 1.0002-3 0.177 0.048 0.002y

Root of tongue 1-2 �0.060 0.024 0.045*1-3 �0.053 0.024 0.0962-3 0.007 0.024 1.000

Tip of tongue 1-2 �0.071 0.040 0.2421-3 �0.065 0.040 0.3312-3 0.006 0.040 1.000

*P\0.05; yP\0.01.

Table V. Comparison of the stages in group 2

Group 2 StagesMean difference

(mm/mm) SD PAnterior contact 1-2 0.017 0.022 1.000

1-3 0.011 0.022 1.0002-3 �0.006 0.022 1.000

Middle part 1-2 0.079 0.044 0.2431-3 0.074 0.044 0.3112-3 �0.005 0.044 1.000

Posterior part 1-2 �0.014 0.046 1.0001-3 0.063 0.046 0.5212-3 0.077 0.046 0.299

Root of tongue 1-2 �0.012 0.023 1.0001-3 �0.025 0.023 0.8302-3 �0.013 0.023 1.000

Tip of tongue 1-2 0.023 0.045 1.0001-3 0.002 0.045 1.0002-3 �0.021 0.045 1.000

Yılmaz et al e419

stage 3 than at stage 1 (P\0.05), showing that this por-tion of the tongue was positioned superiorly at stage 3relative to stage 1. Evaluation of the tongue tip (P0-Ti/P0-I) showed that it was retruded at stage 3 relative tostages 1 and 2 (P\0.001).

Alterations in the contact of the anterior part of thetongue (AM-E/AM-PM) and the movements of the pos-terior portion (PM-PT/PM-PS) and the root of the dorsaltongue (C1-D/C1-Me) were statistically insignificant.

In the control group (group 4) (Table VII), the dis-tance between the middle portion of the dorsal tongueand the palatal mucosa (MM-MT/MM-MS) was


significantly smaller at stage 3 than at stages 1 and 2(P \0.001), showing that this portion of the tonguewas positioned superiorly in stage 3 relative to stages 1and 2. In the evaluation of the posterior portion of thedorsal tongue (PM-PT/PM-PS), a statistically significantincrease was determined at stage 2 relative to stage 1(P\0.05), and a statistically significant decrease was de-termined at stage 3 relative to stage 2 (P\0.001). Thesealterations showed that the posterior portion of thetongue moved upward at stage 2 and downward at stage3. Evaluation of the tongue tip (P0-Ti/P0-I) showed a sta-tistically significant decrease at stage 2 relative to stage 1


Table VI. Comparison of the stages in group 3

Group 3 Stages


Anterior contact 1-2 �0.042 0.029 0.4511-3 0.014 0.029 1.0002-3 0.056 0.029 0.171

Middle part 1-2 0.035 0.045 1.0001-3 0.133 0.045 0.014*2-3 0.098 0.045 0.104

Posterior part 1-2 0.008 0.043 1.0001-3 0.092 0.043 0.1092-3 0.084 0.043 0.166

Root of tongue 1-2 �0.021 0.013 0.3171-3 �0.026 0.013 0.1522-3 �0.005 0.013 1.000

Tip of tongue 1-2 �0.080 0.044 0.2171-3 0.419 0.044 0.000y

2-3 0.499 0.044 0.000y

*P\0.05; yP\0.001.

Table VII. Comparison of the stages in group 4

Group 4 Stages


Anterior contact 1-2 �0.031 0.019 0.1201-3 �0.005 0.018 0.7702-3 0.026 0.018 0.177

Middle part 1-2 �0.056 0.052 0.2941-3 0.204 0.046 0.000y

2-3 0.260 0.058 0.000y

Posterior part 1-2 0.069 0.024 0.010*1-3 �0.074 0.037 0.0572-3 �0.142 0.034 0.000y

Root of tongue 1-2 0.029 0.018 0.1161-3 �0.008 0.020 0.6982-3 �0.037 0.018 0.051

Tip of tongue 1-2 0.095 0.035 0.013*1-3 0.041 0.045 0.3712-3 �0.054 0.045 0.243

*P\0.05; yP\0.001.

Table VIII. Comparison of the groups in stage 1

Stage 1 Groups



Middle part 1-2 0.0642 0.0530 1.00001-3 0.0072 0.0530 1.00002-3 �0.0570 0.0523 1.0000

Posterior part 1-2 0.0364 0.0428 1.00001-3 �0.0486 0.0428 1.00002-3 �0.0850 0.0423 0.2874

Root of tongue 1-2 �0.0223 0.0175 1.00001-3 �0.0173 0.0175 1.00002-3 0.0050 0.0173 1.0000

Tip of tongue 1-2 �0.0666 0.0486 1.00001-3 0.0339 0.0486 1.00002-3 0.1005 0.0480 0.2368

Table IX. Comparison of the groups in stage 2

Stage 2 Groups


Anterior contact 1-2 0.0452 0.0344 1.00001-3 �0.0133 0.0344 1.00002-3 �0.0585 0.0340 0.5336

Middle part 1-2 0.1153 0.0486 0.12121-3 0.0143 0.0486 1.00002-3 �0.1010 0.0480 0.2318

Posterior part 1-2 0.1966 0.0461 0.0003y

1-3 0.1331 0.0461 0.0300*2-3 �0.0635 0.0455 0.9997

Root of tongue 1-2 0.0257 0.0241 1.00001-3 0.0217 0.0241 1.00002-3 �0.0040 0.0238 1.0000

Tip of tongue 1-2 0.0270 0.0462 1.00001-3 0.0250 0.0462 1.00002-3 �0.0020 0.0456 1.0000

*P\0.05; yP\0.001.

e420 Yılmaz et al

(P\0.001) because of the retrusion of the tongue tip atstage 2.

Alterations in the contact of the anterior part of thetongue (AM-E/AM-PM) and the movements of theroot of the dorsal tongue (C1-D/C1-Me) were statisti-cally insignificant.

The stages were also compared between the groups.In stage 1 (Tables VIII and XI), no parameter hada statistically significant difference in the comparisonof the Class II groups (groups 1, 2, and 3). Howeversome differences were determined in the comparisonof the Class II groups with the control group (group 4).


When the degree of contact between the anteriorportion of the tongue and palate (AM-E/AM-PM) wascompared between the groups, it was observed thatthere was a statistically significant decrease in all ClassII groups relative to the control group (P\0.001).

In the comparison of the distance between the middleportion of the dorsal tongue and the palatal mucosa(MM-MT/MM-MS), a statistically significant increasewas found in all Class II groups relative to the controlgroup (P \0.001). This increase showed the inferiorpositioning of the middle portion of the tongue in thepatients with Class II malocclusion. However, no


Table X. Comparison of the groups in stage 3

Stage 3 Groups



Middle part 1-2 0.0483 0.0467 1.00001-3 0.0503 0.0467 1.00002-3 0.0020 0.0461 1.0000

Posterior part 1-2 0.0958 0.0415 0.14161-3 0.0398 0.0415 1.00002-3 �0.0560 0.0409 1.0000

Root of tongue 1-2 0.0054 0.0187 1.00001-3 0.0099 0.0187 1.00002-3 0.0045 0.0185 1.0000

Tip of tongue 1-2 0.0002 0.0329 1.00001-3 �0.0258 0.0329 1.00002-3 �0.0260 0.0325 1.0000

Table XI. Comparison of the Class II groups with thecontrol group

Groups


Stage 1Anterior contact 1-4 �0.11 0.03 0.00z

2-4 �0.17 0.03 0.00z

3-4 �0.17 0.03 0.00z

Middle part 1-4 �0.24 0.05 0.00z

2-4 �0.31 0.05 0.00z

3-4 �0.25 0.05 0.00z

Posterior part 1-4 �0.01 0.04 0.992-4 �0.05 0.04 0.563-4 0.04 0.04 0.66

Root of tongue 1-4 0.17 0.02 0.00z

2-4 0.19 0.02 0.00z

3-4 0.19 0.02 0.00z

Tip of tongue 1-4 �0.24 0.05 0.00z

2-4 �0.17 0.05 0.00z

3-4 �0.27 0.05 0.00z


2-4 �0.17 0.05 0.00z

3-4 �0.27 0.05 0.00z

Middle part 1-4 �0.33 0.05 0.00z

2-4 �0.44 0.05 0.00z

3-4 �0.34 0.05 0.00z

Posterior part 1-4 0.23 0.05 0.00z

2-4 0.04 0.04 0.753-4 0.10 0.04 0.07

Root of tongue 1-4 0.26 0.02 0.00z

2-4 0.23 0.02 0.00z

3-4 0.24 0.02 0.00z

Tip of tongue 1-4 �0.07 0.05 0.292-4 �0.10 0.04 0.083-4 �0.10 0.04 0.09


2-4 �0.19 0.02 0.00z

3-4 �0.19 0.02 0.00z

Middle part 1-4 �0.13 0.05 0.02*2-4 �0.18 0.05 0.00z

3-4 �0.18 0.05 0.00z

Posterior part 1-4 �0.09 0.04 0.092-4 �0.18 0.04 0.00z

3-4 �0.13 0.04 0.01y

Root of tongue 1-4 0.21 0.02 0.00z

2-4 0.21 0.02 0.00z

3-4 0.20 0.02 0.00z

Tip of tongue 1-4 �0.13 0.03 0.00z

2-4 �0.13 0.03 0.00z

3-4 �0.11 0.03 0.00z

*P\0.05; yP\0.01; zP\0.001.

Yılmaz et al e421

statistically significant alteration was observed in theposition of the posterior portion of the dorsal tongue(PM-PT/PM-PS).

Evaluation of the root of the dorsal tongue (C1-D/C1-Me) showed that the distance between the root ofthe tongue and the front point of the atlas increased sig-nificantly in all Class II groups relative to the controlgroup (P\0.001). This increase was due to the inferiorand anterior position of the root of the tongue inpatients with Class II malocclusion.

The tongue-tip (P0-Ti/P0-I) evaluation showed statis-tically significant decreases in all Class II groups relativeto the control group (P\0.001). This decrease showedthe retrusion of the tongue tip in patients with Class IImalocclusion.

In stage 2 (Tables IX and XI), the degree of contactbetween the anterior portion of the tongue and palate,and the position of the middle portion and the root ofthe dorsal tongue showed the same alterations as atstage 1, and these parameters (AM-E/AM-PM, MM-MT/MM-MS, C1-D/C1-Me) were statistically significant in thecomparison of the Class II groups (groups 1, 2, and 3)with the control group (group 4) (P\0.001).

When the position of the posterior portion of the dor-sal tongue (PM-PT/PM-PS) was compared between thegroups, statistically significant increases were deter-mined in the mandibular retrusion group (group 1) rela-tive to group 2 (P \0.001), group 3 (P \0.05), andgroup 4 (P \0.001). These decreases showed that theposterior portion of the dorsal tongue was positionedmore inferiorly in patients with mandibular retrusion.

Evaluation of the tongue tip (P0-Ti/P0-I) showed ret-rusion in all Class II groups relative to the control group,but, contrary to stage 1, it was not statistically signifi-cant at stage 2.


In stage 3 (Tables X and XI), the degree of contactbetween the anterior portion of the tongue and thepalate, the position of the middle portion and the rootof the dorsal tongue, and the tongue tip showed the


Fig 3. Graphics showing the anterior contact of tongueand palate (mm/mm).

Fig 4. Graphics showing the middle portion of the dorsaltongue (mm/mm).

Fig 5. Graphics showing the posterior portion of the dor-sal tongue (mm/mm).

Fig 6. Graphics showing the root of the dorsal tongue.

e422 Yılmaz et al

same alterations as at stage 1, and these parameters(AM-E/AM-PM, MM-MT/MM-MS, C1-D/C1-Me, P0-Ti/P0-I) were statistically significant in the comparison ofthe Class II groups with the control group (group 4).

Evaluation of the position of the posterior portion ofthe dorsal tongue (PM-PT/PM-PS) showed that it waspositioned superiorly in groups 2 and 3 in the compari-son with the control group (P \0.001 and P \0.01,respectively). The same alteration was also observed atgroup 1, but it was statistically insignificant.

Graphics of all measurements are presented inFigures 3-7.

DISCUSSION

Deglutition is a complex action involving multipleanatomic structures in the oral cavity, pharynx, larynx,and esophagus. During normal swallowing, the tonguetip rests on the lingual part of the dentoalveolar area,and the middle portion of the tongue elevates fromfront to back. In recent years, some investigators sug-gested that there are correlations between deglutitivetongue movements and maxillofacial morphol-ogy.9,10,12 Posture and function of the tongue havebeen found to be significantly correlated with jawrelationship, abnormality of the dental arch form, and


abnormal tooth positions. Tongue movements indeglutition immediately adapt to changes in the localenvironment.17

In recent years, the movements of the anatomicstructures that participate in deglutition have beeninvestigated by several methods: ultrasonography,9 elec-tropalatography,10 cineradiography,11 electromyogra-phy,19 and electromagnetic articulography.20 However,all these techniques have various disadvantages, suchas radiation exposure, the risk of aspiration of barium,and indirect visualization of the involved struc-tures.11,12,21 Dynamic MRI is a noninvasive methodthat has recently become available in the evaluation ofdeglutition. New developments in MRI techniquesmade it possible to provide dynamic images in cine-MRI that produces a series of anatomic images with pe-riodic motion. Recently, dynamic MRI has been used toevaluate tongue movements and the anatomic struc-tures involved in deglutition,13-17 vocal fold motion,22

pharyngeal airway space,23,24 and laryngeal andtracheal motion during breathing25; this technique hasthe advantages of noninvasiveness, absence of ionizingradiation exposure, and the capability of imaging soft-tissue anatomy during motion. On the other hand, Ana-gnostara et al26 reported that this technique has limitedutility as a diagnostic tool for deglutition studies under


Fig 7. Graphics showing the tongue tip (mm/mm).

Yılmaz et al e423

physiologic conditions because the examination is per-formed while the subjects are in a supine position. How-ever, since all the subjects were in a supine positionduring the examinations, the comparison of the selectedgroups is convenient with this technique.13,14,17 In thestudies of Fujiki et al,11,12 the swallowing events wererecorded 3 times, but, in our study, because of thehigh cost of the technique, only 1 scan was performed.The patients’ supine position and the high cost of thetechnique are the disadvantages of cine MRI.

Dynamic images of anatomic structures involved indeglutition can be obtained by using fast scan tech-niques such as echo-planar imaging or fast gradientecho techniques such as fast low-angle shot, fast fieldecho, or turbo field echo. Anagnostara et al26 comparedthese sequences and reported that the turbo field echosequence provided the best temporal resolution andwas optimal for the investigation of swallowing func-tion. In our study, the turbo field echo sequence wasperformed.

In many studies, it has been suggested that tonguemovements during deglutition might be related to themaxillofacial morphology of the patients. In our study,the patients with Class II skeletal malocclusion were di-vided into 3 groups after evaluation of the SNA, SNB,and ANB angles, and N vertical-A and N vertical-Pg lin-ear measurements to determine the source of the skeletalmalocclusion. Not only the relationship between themaxilla and the mandible, but also the relationship be-tween the jaws and the anterior cranial base were con-sidered while the groups of skeletal Class IImalocclusion were being created.

Evaluation of the contact between the anterior por-tion of the tongue and the rugae area of the hard palateshowed a significant decrease in all Class II malocclusiongroups relative to the control group. Similar results werealso found in the patients with Class III malocclusion inour preceding study.14 Therefore, the results of these 2studies suggest that increased or decreased overjet de-creases the contact between the anterior portion of the


tongue and the rugae area of the hard palate because,in both of these conditions, it was difficult to seal offthe front of the mouth during swallowing. Lips makecontact to provide the seal in the anterior region of themouth in patients with normal overjet. Nevertheless,this physiologic seal is usually provided by tongue-lip-maxillary incisor contact in subjects with Class II or ClassIII malocclusion; in this situation, the contact betweenthe anterior portion of the tongue and the rugae areaof the hard palate decreases. Supporting our results,Subtelny and Subtelny27 also reported that subjectswith maxillary protrusion, maxillary deficiency, andopen bite had difficulties in attaining an anterior seal,and these patients used the anterior portion of theirtongue to close the anterior opening.

In all Class II malocclusion groups, the middle portionof the dorsal tongue was positioned more superiorly inall deglutition stages relative to the control group. Theresult conflicted with the results of our previous studiesthat evaluated tongue movements in patients with openbite and Class III malocclusion.13,14 In these studies, themiddle portion of the dorsal tongue did not show anysignificant difference in the comparison with thecontrol group. However, this study showed that Class IImalocclusion affected the movements of the middleportion of the tongue during deglutition. In ouropinion, it depended on the retrusion of the tonguetip and the decreased contact of the anterior portionof tongue and the rugae area of the hard palate. Thiscontact also decreased in patients with Class IIImalocclusion, but the position of the middle portionwas not affected in these patients, probably dependingon the anterior positioning of the tongue tip inpatients with a Class III skeletal relationship.14 Akinet al13 reported that, in patients with open bite, the con-tact of the anterior portion of the tongue and the rugaearea of the hard palate showed no statistically significantdifference, but the middle portion of the tongue waslower, and the tongue tip moved anteriorly. In the lightof these findings, it can be concluded that the position ofthe tongue tip and the anterior and middle portions ofthe tongue affected the movements of each other duringdeglutition.

The posterior portion of the dorsal tongue did notshow significant differences at stage 1, but, at stage 2,it was positioned more inferiorly in patients with man-dibular retrusion (group 1) relative to the other 3 groups.At stage 3, this portion was positioned superiorly inpatients with Class II malocclusion relative to the controlgroup. However, it was not statistically significant inpatients with mandibular retrusion. In this group, infe-rior positioning of the posterior portion of the dorsaltongue at stage 2 decreased the elevation of this portion


e424 Yılmaz et al

at stage 3. In patients with Class III malocclusion, theposterior portion of the tongue was positioned more in-feriorly in all Class III groups relative to the controlgroup.14 These results show that dentofacial morphol-ogy affects the movements of the posterior portion ofthe tongue during deglutition. In the evaluation oftongue movements relative to the deglutition stages, itwas determined that the posterior portion of the dorsaltongue moved inferiorly at stage 2 and superiorly atstage 3 in patients with mandibular retrusion. However,in the control group, it moved superiorly at the secondstage and inferiorly at the third stage in the controlgroup. During bolus transfer, a fluctuation motion wasdetermined at the posterior portion of the dorsal tonguein these 2 groups, but the directions of the motions wereopposite. The motions in groups 2 and 3 were not signif-icant. Fujiki et al11 also reported fluctuation movementsin patients with open bite and normal overbite. This isa physiologic function of the tongue for the transporta-tion of the bolus.

Evaluation of the root of the tongue showed that itwas positioned more inferiorly and anteriorly in all ClassII groups relative to the control group at all stages. Thesame finding was also reported for the patients withClass III malocclusion.14 In the evaluation of the deglu-tition stages, it was observed that, in the mandibular ret-rusion group, the root of the tongue moved in an inferiorand anterior direction at stage 2. In this group, the pos-terior portion of the dorsal tongue also moved inferiorlyat stage 2. Probably, the movement of the root of thetongue was affected by the movement of the posteriorportion of the dorsal tongue.

The results of our study showed that the tongue tipswere positioned more posteriorly in all Class II groupsthan in the Class I control group. However, the retrusionof the tongue tip was not statistically significant atstage 2. When the movement of the tongue tip was eval-uated according to the stages, it was observed that, inthe mandibular retrusion andmaxillary protrusion group(group 3), it moved in the posterior direction at stage 3relative to stages 1 and 2. The reason for not moving inthe posterior direction at stage 2 was probably to createan anterior seal to prevent exudation and to help thetransportation of the bolus toward the pharyngealarea. However, in the control group, the retrusion wasobserved at stage 2 relative to stage 1. In the other ClassII groups (groups 1 and 2), tongue-tip movements dur-ing deglutition were not statistically significant. In someprevious studies, it was shown that tongue-tip positionwas closely related to overbite, overjet, and skeletalmorphology.11,13,14 Gorgulu et al,14 Subtelny and Sub-telny,27 and Fuhrmann and Diedrich28 reported thatthe tongue tip was positionedmore anteriorly in patients


with Class III malocclusion. Similarly, Fujiki et al11 andAkin et al13 showed that the tongue tip was more protru-sive during deglutition in patients with open bite. Similarto these results, tongue-tip position was affected by theClass II malocclusion, and it was retruded in these pa-tients. On the other hand, its movements were affectedonly when both jaws were malpositioned.

CONCLUSIONS

1. Dentofacial morphology affects the position of thetongue and its deglutitive movements.

2. In patients with Class II malocclusion, the dorsaltongue is positioned more superiorly, and thetongue tip is positioned more posteriorly than inthose with skeletal Class I malocclusion.

3. Further studies are needed to determine the adaptivechanges after the correction of Class II malocclusion,and this is the issue of another investigation plannedin our department.

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