Oral Diseases (2015) 21, 483–492 doi:10.1111/odi.12307 © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd All rights reserved www.wiley.com
ORIGINAL ARTICLE
Articulation and oromyofunctional behavior in children seeking orthodontic treatment KM Van Lierde1, A Luyten1, E D’haeseleer1, G Van Maele2, L Becue1, E Fonteyne1, P Corthals3, G De Pauw4 1
Department of Speech, Language and Hearing Sciences, Ghent University, Gent; 2Department of Biostatistics, Ghent University, Gent; 3Department of Speech, Language and Hearing Sciences, University College Ghent, Ghent University & Faculty of Education, Health and Social Work, Gent; 4Department of Orthodontics, Ghent University, Gent, Belgium
OBJECTIVES: The purpose of this controlled study is to document articulation and oromyofunctional behavior in children seeking orthodontic treatment. In addition, relations between malocclusions, articulation, and oromyofunctional behavior are studied. MATERIALS AND METHODS: The study included 56 children seeking orthodontic treatment. The control group, consisting of 54 subjects matched for age and gender, did not undergo orthodontic intervention. To determine the impact of the occlusion on speech, the Oral Health Impact Profile was used. Speech characteristics, intelligibility and several lip and tongue functions were analyzed using consensus evaluations. RESULTS: A significant impact of the occlusion on speech and more articulation disorders for/s,n,l,t/were found in the subjects seeking orthodontic treatment. Several other phenomena were seen more often in this group, namely more impaired lip positioning during swallowing, impaired tongue function at rest, mouth breathing, open mouth posture, lip sucking/biting, anterior tongue position at rest, and tongue thrust. Moreover, all children with a tongue thrust showed an anterior tongue position at rest. CONCLUSIONS: Children seeking orthodontics have articulatory and oromyofunctional disorders. To what extent a combined orthodontic and logopaedic treatment can result in optimal oral health (i.e. perfect dentofacial unit with perfect articulation) is subject for further multidisciplinary research. Oral Diseases (2015) 21, 483–492 Keywords: orthodontics; speech; oromyofunctional behavior; malocclusion Correspondence: Kristiane M. van Lierde, Department of Speech, Language and Hearing Sciences, Ghent University, 2P1, De Pintelaan 185 9000 Gent, Belgium. Tel: +32 9 332 23 91, Fax: +32 9 332 49 93, E-mail: [email protected] Received 4 September 2014; revised 26 November 2014; accepted 12 December 2014
Introduction The final process involved in speech production is articulation. Articulation is the molding of the airstream into recognizable speech sounds by several structures in the mouth, the articulators. The most important static or immovable articulators are the hard palate, the alveolar ridge, and the teeth. Apart from serving a cosmetic purpose, the teeth also play a part in the articulation of specific speech sounds of several languages such as Flemish (spoken in Flanders, the northern part of Belgium). The teeth are directly involved in the production of/f/and/v/. Moreover, they help to produce the frication in sounds such as/s/ and/z/as the breath stream passes over the lower edges of the incisor teeth (Pena-Brooks and Hedge, 2000). Any abnormality of the position of the teeth, mandible, or maxilla could negatively affect the production of specific speech sounds, especially in children during speech-language development. In case of deformations of the dental arch and facial disharmony during dentofacial development, patients (and their parents) are motivated to seek orthodontic care. Very few studies have investigated articulation and oromyofunctional behavior in children seeking orthodontic treatment. Table 1 provides a summary of recent studies regarding the presence of articulation and oromyofunctional disorders in children with orthodontic disorders. Several studies reported a relation between orthodontic disorders and the presence of articulation disorders in different languages. Also, the presence of some types of oromyofunctional disorders in relation to orthodontic disorders is reported. In most of these studies, no age- and gender-matched control groups were used, and very few consensus evaluations were performed during speech assessments. Only in the study of Sahad et al (2008), an articulation test was performed by two experienced speech therapists (but no degree of consensus is provided). Moreover, no controlled studies were found in Flemish or Dutch. The purpose of this controlled study is to perform an in-depth consensus analysis of articulation and oromyofunctional behavior in Dutch-speaking children seeking
Oral Diseases
Language
Czech
English
German
Brazilian Portuguese
Authors
Jindra et al (2003)
Onyeasa and Aderinokun (2003)
Grabowski et al (2007)
Sahad et al (2008)
•
•
•
•
Relationship between occlusal aspects and anterior lisping and/or anterior tongue thrust in the articulation of/t//d//n//l/
Relation between OMD in early mixed dentition
Relation between Dental Aesthetic Index and perception of esthetics, function and speech
Relation between speech disorders and orthodontic anomaly
Purpose
• • • •
• • • •
• • • • •
• • •
333 children 157 males/176 females Age range: 3–6 year No control group
2275 children 1114 males/1161 females m.a.: 8.3 year No control group
614 children 327 males/287 females m.a.: 14.9 y age range: 12–18 year No control group
24 children m.a.: 12.0 year Control group: 19 children (m.a.: 12.3 year)
Subjects
•
•
•
• • • •
Dental Aesthetic index Questionnaire No consensus evaluation
Articulation during the production of a Czech logopaedic poem No consensus evaluation
Assessment and classification of vertical interincisal trespass Articulation test (auxiliary test-personal context, word lists, spontaneous naming, phonoarticulatory assessment) Consensus evaluation but no percentage of consensus
Observation of mouth/tongue posture swallowing pattern articulation/l//n//d//t//s/ No consensus evaluation
• • •
•
•
Methods
Table 1 Summary of recent studies regarding the presence of articulation and oromyofunctional disorders in children with orthodontic disorders
•
• •
•
•
•
•
•
•
484 (continued)
Significant relation between open bite and anterior lisping and/or anterior tongue thrust during the articulation of/t/,/d/,/n/, and/l/
Confirmed the role of the frontal segment of dental arch in sibilants Disorders of sibilants might occur in patients with severe orthodontic anomaly of the frontal segment Significant correlation between Dental Aesthetic Index and children’s perception of the appearance of the teeth Significant correlation between appearance of teeth and speech and biting/chewing and speech Frequency of OMD significantly higher in increased maxillary overjet, frontal open bite, lateral cross-bite and mandibular prognathism Prevalence of OMD higher in mixed compared to primary dentition Articulation disorders in 17.5% of the patients Significantly more articulation disorders in males
Results Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
Brazilian Portuguese
Italian
Swedish
Brazilian Portuguese
Peres et al (2011)
Farronato et al (2012)
Dimberg et al (2013)
Leme et al (2013)
OMD, oromyofunctional disorders.
Language
Authors
Table 1 (continued)
•
•
•
•
Relation between oral habits and functions and oral health-related quality of life
Prevalence of malocclusion at ages 3 and 7 years (longitudinal study)
Relation between malocclusions and articulation
Relation between malocclusion and self-perception of oral appearance/function
Purpose
• • •
• • • • • • • • • • • 328 children Age range: 8–14 year Control group: habit and habit-free group
528 three-year-old/ 386 seven-year-old children No control group
880 children 448 males/432 females Age range: 6–10 year No control group
717 adolescents 377 males/340 females 12/15 years old No control group
Subjects
• • • • • •
• • • •
•
Nordic Orofacial Test-Screening Quality of Life (QOL) Questionnaire No consensus evaluation
Clinical examination of malocclusions Questionnaire regarding oral habits No consensus evaluation
Articulation test with phonetic analysis No consensus evaluation
Malocclusion measured with Dental Aesthetic Index Questionnaire No consensus evaluation
Methods
•
• • • •
• •
•
•
•
71% showed oral habits (habit group) Females prevalence of oral habits More affected sensory functions in habit group Results of the Nordic Orofacial test positively correlated with the questionnaire results Orofacal dysfunctions were associated with worse QOL
Higher prevalence of malocclusion at 3 years of age Significant relation between anterior open bite and posterior cross-bite and sucking habits
Correlations between articulation disorders, Class III occlusion, diastema, increase in overjet, and presence of open and deep bite
Missing teeth and the presence open bite: risk indicators for speech capability Molar relationship: risk indicator for chewing capability
Results
Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
485
Oral Diseases
Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
486
orthodontic treatment. In addition, relations between occlusal findings, and articulation characteristics and the oromyofunctional behavior are studied. Given the growing demands for perfect articulation in today’s communication-based society and the lack of specialized speech analysis studies of children seeking orthodontic services, additional research is warranted. Detailed information on speech and oromyofunctional characteristics in children seeking orthodontic treatment should lead to better multidisciplinary guidance of these patients and a better long-term outcome regarding dentofacial appearance and speech.
Methods and materials This study was approved by the human subject committee of the Ghent University (name: EC UZG, registration number 2013/761). Written informed consent was obtained from each participants’ parents.
Subjects All children were native speakers of Flemish, attended regular schools, and had no history of craniofacial anomalies, or presence of ear, nose, throat, or neurological pathologies. The original study group included 60 children (34 females and 26 males) with a mean age of 10.3 years (range: 7–12 years); they were consulting the Department of Orthodontics at the Ghent University. Ninety-three percent (52/56) of the children were consulting an orthodontist for the first time. Seven percent (4/56) had a functional appliance/activator (not used during speech assessment) (mean period: 12 months, range: 10–24 months). Nearly 11 percent (6/56) of the children were in the first translational period (early mixed dentition), 21% (12/56) were in the intertranslational period, 48% (27/56) were in the second translational period (late mixed dentition), and 20% (11/56) had permanent dentition. Four children were excluded on the day of testing due to temporary nasal obstruction caused by a nasal cold. The final study group included 56 children (32 females and 24 males) with a mean age of 10.2 years (range: 7–12 years). The gender- and age-matched control group, not undergoing or being referred for orthodontic treatment, was randomly selected and consisted of 54 Flemish-speaking subjects (29 females and 25 males) with a mean age of 9.3 years (range: 6–12 years). Nearly 4 percent (2/54) had a deciduous dentition, 37% (20/54) were in the first translational period (early mixed dentition), 48% (26/54) were in the translational period, and 11% (6/54) had permanent dentition. An independent Student’s t-test showed no significant age and gender differences between the subjects in the experimental group and those in the control group. In comparison with the control group, significantly more children in the study group (11%) were in the first translational period (early mixed dentition). Two orthodontists performed the intra- and extraoral orthodontic examinations. The types of malocclusions and dental clinical findings in the experimental group are mentioned in Table 2. To classify malocclusions, Angle’s taxonomy was used, with a subdivision in Class II malocclusions (Class II division with proclination of the upper front teeth and Class II division 2 with retroclination of the upper front teeth). Other functional disturbances (mandibular displacements) were noted as well as different occlusal parameters (overbite, overjet, cross-bite,. . .). Definitions and distribution are given in Table 2.
Table 2 Occlusal findings with definitions (Proffit et al, 1986) in the children seeking orthodontic treatment Dental relationship Class I Class II/1
Class II/2
Class III Mandibular displacement (forced bite) Absent To the left To the right Anteriorly Buccal cross-bite
Absent Unilateral Bilateral Anterior open bite
Absent Present Overjet Normal Increased Reduced Overbite Normal Reduced, edge to edge Reduced, negative Increased
Criteria/definition Angle’s classification for a normal relationship between upper and lower jaw Angle’s classification of a retruded mandible in regard to the maxilla with proclination of the upper front teeth Angle’s classification of a retruded mandible in regard to the maxilla with retroclination of the upper front teeth Angle’s classification of a protruded mandible in regard to the maxilla When closing from the rest position, the mandible displaces to avoid a premature contact into maximum interdigitation
Percentage (n) 32 (18/56) 52 (29/56)
16 (9/56)
0 (0/56)
87 (49/56) 4 (2/56) 7 (4/56) 2 (1/56) The buccal cusps of the lower premolars and/or molars occlude buccally to the buccal cusps of the upper premolars and/or molars 61 (34/56) 34 (19/56) 5 (3/56) The lower incisors do not occlude with the opposing upper incisors or the palatal mucosa when the buccal segment teeth are in occlusion 79 (44/56) 21 (12/56) Distance between the upper and lower incisors in the horizontal plane (mm) 2–4 mm More than 4 mm Less than 2 mm Vertical overlap of the upper and lower incisors when viewed anteriorly (mm) One-third to one-half coverage of the lower incisors No vertical overlap but the incisal edges of upper and lower incisors make contact No vertical contact between the incisors Greater than one-half coverage of the lower incisors
12 (7/56) 88 (49/56) 0 (0/56)
41 (23/56) 11 (6/56) 11 (6/56) 37 (21/56)
Methods
(Van der Meulen et al, 2008). A high score (on a scale ranging from 0 to 4) implies a high impact of the occlusion on speech characteristics.
Specific assessment techniques were used to determine speech characteristics (speech intelligibility and phonetic characteristics) and oromyofunctional behavior (Van Lierde et al, 2012).
Articulation and speech intelligibility
Oral health impact profile To determine the impact of the occlusion on speech characteristics, one question (‘did you experience any speech problem related to your teeth?’) of the Dutch version of the Oral Health Impact Profile (OHIP-14) was used
Oral Diseases
To assess articulation, speech samples were elicited by means of a picture-naming test. This test requires subjects to name black and white drawings of common objects and actions. It yields a speech sample, which contains instances of all Dutch single sounds, and most consonant clusters in all permissible syllable positions (see Appendix) (Van Lierde et al, 2001, 2011). The samples were recorded digitally for fur-
Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
ther analysis. The evaluation included a phonetic inventory and phonetic analysis. The phonetic inventory revealed which consonants and vowels the patient was capable of producing correctly in his/her native language. This analysis was conducted without making reference to the intended target sounds. A sound was considered to be present in the inventory when at least two instances of correct production (i.e. consistent with the standard realization of the sound) were found. In the relational analysis, consonant and vowel productions were compared with target productions and analyzed for error types on the segmental level. The speech samples collected by means of a picture-naming test were also used to judge overall speech intelligibility of words and sentences. An ordinal scale with four levels was used to rate speech intelligibility (0 = normal speech intelligibility, 1 = mildly impaired, 2 = moderately impaired, and 3 = severely impaired speech intelligibility). All analyses of articulation and intelligibility were based on a consensus narrow phonetic transcription made by two speech-language pathologists (L.B., E.F) using the symbols and diacritics of the International Phonetic Alphabet. Both speech-language pathologists were blinded to the subject’s condition, that is, whether a given subject belonged to the experimental or the control group. Moreover, the speech-language pathologists first simultaneously and independently transcribed the samples before comparing transcriptions and intelligibility ratings aiming at a consensus. Only spontaneous and unequivocal namings of the stimulus picture were retained in the analysis. The speech samples thus gathered consisted of 135 different words.
Oromyofunctional assessment During oromyofunctional assessments, five functions were verified as proposed in the protocol of Lembrechts et al (1999). These functions were as follows: lip function (lip position at rest, lip closure, dispersion of the corners of the mouth, lip protrusion, lip position during swallowing), tongue function (tongue position at rest, tongue protrusion, tongue retraction, tongue lifting against the upper lip, tongue depression against the lower lip, lateral movements of the tongue, tongue position during swallowing), blowing, sucking, and swallowing. There is an anterior interdental/addental tongue thrust when the tongue tip is between/against the central incisors. When the tongue blade is between the molars unilaterally or bilaterally, there is a unilateral or bilateral tongue thrust (Logemann, 2000; Pena-Brooks and Hedge, 2000). A three-point rating scale was used (0 = normal function, 1 = decreased function, 2 = severely disordered/function impossible). The following oromyofunctional disorders were verified: presence of sucking habits, drooling, mouth breathing, lip incompetence, and bruxism. The experienced speech-language pathologists first rated independently. In case of disagreement, the samples were replayed and discussed until a consensus was reached. A questionnaire regarding oral habits (thumb or finger sucking, pacifier sucking, mouth breathing, habitual open mouth posture, lip biting or sucking, drooling, bruxism, nail biting, tongue position at rest; unphysiological: tongue tip between or against the central incisors; normal: tongue tip at the upper or lower alveolar ridge) and swallowing was used.
Statistical analysis For the comparisons of overall satisfaction and the impact on speech in both groups, a Mann–Whitney U-test was performed. For the comparisons of the phonetic articulation characteristics and oromyofunctional disorders and to verify the associations between phonetic articulatory, oromyofunctional, and orthodontic disorders, Fisher’s exact test was used. All significance levels were set at P = 0.05.
Results Oral health impact profile The mean total OHIP score for the subjects seeking orthodontic treatment was 1.05 (s.d.: 1.15 range: 0–4). The mean total OHIP score for the control subjects was 0.4
(s.d.: 0.71 range: 0–1). The Mann–Whitney U-test showed a significantly increased impact of the occlusion on speech (P = 0.001) in the subjects seeking orthodontic treatment in comparison with the control subjects. No gender- and age-related differences in OHIP outcome were found.
487
Articulation and speech intelligibility The phonetic inventory was complete in all subjects of both groups (100% consensus evaluation). The results of the in-depth phonetic analysis (consensus evaluation 87%) are provided in Table 3. Phonetic articulation disorders of/s/,/n/,/l/,/t/,/d/,/p/,/b/, and/m/were found in the subjects seeking orthodontic treatment, with disorders of/s/,/n/,/l/, and/t/occurring significantly more often. The Mann–Whitney U-test revealed that children in the orthodontic group produced more phonetic disorders per child (P < 0.001) (mean number of phonetic disorders/child: 2.3 sounds, s.d.: 1.92, range: 0–5) in comparison with children without orthodontics (mean number of phonetic disorders/child: 0.9 sounds, s.d.: 1.51, range: 0–5). Normal speech intelligibility (100% consensus evaluation) was seen in both groups. Oromyofunctional behavior The types of oromyofunctional disorders in both groups are provided in Table 4. Significantly more children seeking orthodontic treatment showed an impaired lip position during swallowing (P = 0.006) and an impaired tongue function at rest (P < 0.001) in comparison with the control group children. Lip function at rest (P = 0.243), lip closure (P = 1.00), dispersion of the corners of the mouth (P = 0.082), and lip protrusion (P = 0.896) did not differ significantly in both groups. Moreover, no significant differences were found for tongue protrusion (P = 0.618), tongue retraction (P = 1.000), tongue lifting/depression (P = 0.482/P = 0.676), and lateral movements of the tongue (P = 0.266) between both groups. A Fisher’s exact test revealed a significant association between anterior tongue position at rest and tongue thrust or visceral swallowing pattern (P < 0.01). All children with a tongue thrust had an anterior tongue position at rest. No significant link was found between anterior tongue position at rest and persistent sucking behavior (P = 0.780). The types of oral habits (based on a questionnaire) in both groups are provided in Table 5. Significantly more control group children showed pacifier sucking (P = 0.026) in comparison with the children seeking orthodontic treatment. The latter group of children showed significantly more lip incompetence during breathing (P = 0.002), habitual open mouth posture (P < 0.001), lip sucking/biting (P = 0.002), anterior tongue position at rest (P < 0.01), and tongue thrust (P = 0.03) in comparison with the control group. No significant differences between both groups were found for thumb/finger sucking, drooling, bruxism, and nail biting. The children seeking orthodontic treatment (mean number of oral habits: 3.3, s.d.: 1.84, range: 0–7) showed significantly more (P < 0.001) oral habits than children in the control group (mean number of oral habits: 1.4, s.d.: 1.44, range: 0–5).
Oral Diseases
Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
488
Table 3 Type of phonetic articulation disorders with definitions (Pena-Brooks and Hedge, 2000) in children seeking orthodontic treatment (n = 56) and in children without further orthodontic treatment (n = 54). The level of significance (P-value, Fisher’s exact test) between the results of the children seeking orthodontic treatment and the children without further orthodontics is provided
Type of phonetic articulation disorder Sigmatism Sigmatism addentalis Sigmatism stridens Sigmatism simplex Sigmatism labiodentalis Sigmatism lateroflexus Sigmatism interdentalis Sigmatism palatalis Phonetic disorder of the/n/ Addental production of the/n/ Interdental production of the/n/ Lambdacism Lambdacism addentalis Lambdacism interdentalis Lambdacism lateroflexus Phonetic disorder of the/t/ Addental production of the/t/ Interdental production of the/t/ Tensed/t/ Phonetic disorder of the/d/ Addental production of the/d/ Interdental production of the/d/ Multiple interdental productions Multiple addental productions Phonetic disorder of the bilabials
Criteria/definition Phonetic disorder of the/s/ /s/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /s/sound accompanied with a whistle sound /s/sound without sufficient frication /s/sound is produced between the lower lip and the upper incisors (instead of between the central incisors) /s/sound with tongue tip against the canine tooth /s/sound with the tongue tip between the central incisors /s/sound with the tongue tip against the more posterior part of the palate /n/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /n/sound with the tongue tip between the central incisors Phonetic disorder of the/l/ /l/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /l/sound with the tongue tip between the central incisors /l/sound with the tongue tip against the canine tooth /t/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /t/sound with the tongue tip between the central incisors /t/sound followed by a slight/s/sound /d/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /d/sound with the tongue tip between the central incisors Interdental production of/s/,/t/,/d/,/n/,/l/,/z/ Addental production of/s/,/t/,/d/,/n/,/l/,/z/ Phonetic disorder of the/p/,/b/,/m/
Children seeking orthodontics % (n)
Children without orthodontics % (n)
Level of significance P-value
59 (33/56) 25 (14/56)
22 (12/54) 4 (2/54)
ORIGINAL ARTICLE
Articulation and oromyofunctional behavior in children seeking orthodontic treatment KM Van Lierde1, A Luyten1, E D’haeseleer1, G Van Maele2, L Becue1, E Fonteyne1, P Corthals3, G De Pauw4 1
Department of Speech, Language and Hearing Sciences, Ghent University, Gent; 2Department of Biostatistics, Ghent University, Gent; 3Department of Speech, Language and Hearing Sciences, University College Ghent, Ghent University & Faculty of Education, Health and Social Work, Gent; 4Department of Orthodontics, Ghent University, Gent, Belgium
OBJECTIVES: The purpose of this controlled study is to document articulation and oromyofunctional behavior in children seeking orthodontic treatment. In addition, relations between malocclusions, articulation, and oromyofunctional behavior are studied. MATERIALS AND METHODS: The study included 56 children seeking orthodontic treatment. The control group, consisting of 54 subjects matched for age and gender, did not undergo orthodontic intervention. To determine the impact of the occlusion on speech, the Oral Health Impact Profile was used. Speech characteristics, intelligibility and several lip and tongue functions were analyzed using consensus evaluations. RESULTS: A significant impact of the occlusion on speech and more articulation disorders for/s,n,l,t/were found in the subjects seeking orthodontic treatment. Several other phenomena were seen more often in this group, namely more impaired lip positioning during swallowing, impaired tongue function at rest, mouth breathing, open mouth posture, lip sucking/biting, anterior tongue position at rest, and tongue thrust. Moreover, all children with a tongue thrust showed an anterior tongue position at rest. CONCLUSIONS: Children seeking orthodontics have articulatory and oromyofunctional disorders. To what extent a combined orthodontic and logopaedic treatment can result in optimal oral health (i.e. perfect dentofacial unit with perfect articulation) is subject for further multidisciplinary research. Oral Diseases (2015) 21, 483–492 Keywords: orthodontics; speech; oromyofunctional behavior; malocclusion Correspondence: Kristiane M. van Lierde, Department of Speech, Language and Hearing Sciences, Ghent University, 2P1, De Pintelaan 185 9000 Gent, Belgium. Tel: +32 9 332 23 91, Fax: +32 9 332 49 93, E-mail: [email protected] Received 4 September 2014; revised 26 November 2014; accepted 12 December 2014
Introduction The final process involved in speech production is articulation. Articulation is the molding of the airstream into recognizable speech sounds by several structures in the mouth, the articulators. The most important static or immovable articulators are the hard palate, the alveolar ridge, and the teeth. Apart from serving a cosmetic purpose, the teeth also play a part in the articulation of specific speech sounds of several languages such as Flemish (spoken in Flanders, the northern part of Belgium). The teeth are directly involved in the production of/f/and/v/. Moreover, they help to produce the frication in sounds such as/s/ and/z/as the breath stream passes over the lower edges of the incisor teeth (Pena-Brooks and Hedge, 2000). Any abnormality of the position of the teeth, mandible, or maxilla could negatively affect the production of specific speech sounds, especially in children during speech-language development. In case of deformations of the dental arch and facial disharmony during dentofacial development, patients (and their parents) are motivated to seek orthodontic care. Very few studies have investigated articulation and oromyofunctional behavior in children seeking orthodontic treatment. Table 1 provides a summary of recent studies regarding the presence of articulation and oromyofunctional disorders in children with orthodontic disorders. Several studies reported a relation between orthodontic disorders and the presence of articulation disorders in different languages. Also, the presence of some types of oromyofunctional disorders in relation to orthodontic disorders is reported. In most of these studies, no age- and gender-matched control groups were used, and very few consensus evaluations were performed during speech assessments. Only in the study of Sahad et al (2008), an articulation test was performed by two experienced speech therapists (but no degree of consensus is provided). Moreover, no controlled studies were found in Flemish or Dutch. The purpose of this controlled study is to perform an in-depth consensus analysis of articulation and oromyofunctional behavior in Dutch-speaking children seeking
Oral Diseases
Language
Czech
English
German
Brazilian Portuguese
Authors
Jindra et al (2003)
Onyeasa and Aderinokun (2003)
Grabowski et al (2007)
Sahad et al (2008)
•
•
•
•
Relationship between occlusal aspects and anterior lisping and/or anterior tongue thrust in the articulation of/t//d//n//l/
Relation between OMD in early mixed dentition
Relation between Dental Aesthetic Index and perception of esthetics, function and speech
Relation between speech disorders and orthodontic anomaly
Purpose
• • • •
• • • •
• • • • •
• • •
333 children 157 males/176 females Age range: 3–6 year No control group
2275 children 1114 males/1161 females m.a.: 8.3 year No control group
614 children 327 males/287 females m.a.: 14.9 y age range: 12–18 year No control group
24 children m.a.: 12.0 year Control group: 19 children (m.a.: 12.3 year)
Subjects
•
•
•
• • • •
Dental Aesthetic index Questionnaire No consensus evaluation
Articulation during the production of a Czech logopaedic poem No consensus evaluation
Assessment and classification of vertical interincisal trespass Articulation test (auxiliary test-personal context, word lists, spontaneous naming, phonoarticulatory assessment) Consensus evaluation but no percentage of consensus
Observation of mouth/tongue posture swallowing pattern articulation/l//n//d//t//s/ No consensus evaluation
• • •
•
•
Methods
Table 1 Summary of recent studies regarding the presence of articulation and oromyofunctional disorders in children with orthodontic disorders
•
• •
•
•
•
•
•
•
484 (continued)
Significant relation between open bite and anterior lisping and/or anterior tongue thrust during the articulation of/t/,/d/,/n/, and/l/
Confirmed the role of the frontal segment of dental arch in sibilants Disorders of sibilants might occur in patients with severe orthodontic anomaly of the frontal segment Significant correlation between Dental Aesthetic Index and children’s perception of the appearance of the teeth Significant correlation between appearance of teeth and speech and biting/chewing and speech Frequency of OMD significantly higher in increased maxillary overjet, frontal open bite, lateral cross-bite and mandibular prognathism Prevalence of OMD higher in mixed compared to primary dentition Articulation disorders in 17.5% of the patients Significantly more articulation disorders in males
Results Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
Brazilian Portuguese
Italian
Swedish
Brazilian Portuguese
Peres et al (2011)
Farronato et al (2012)
Dimberg et al (2013)
Leme et al (2013)
OMD, oromyofunctional disorders.
Language
Authors
Table 1 (continued)
•
•
•
•
Relation between oral habits and functions and oral health-related quality of life
Prevalence of malocclusion at ages 3 and 7 years (longitudinal study)
Relation between malocclusions and articulation
Relation between malocclusion and self-perception of oral appearance/function
Purpose
• • •
• • • • • • • • • • • 328 children Age range: 8–14 year Control group: habit and habit-free group
528 three-year-old/ 386 seven-year-old children No control group
880 children 448 males/432 females Age range: 6–10 year No control group
717 adolescents 377 males/340 females 12/15 years old No control group
Subjects
• • • • • •
• • • •
•
Nordic Orofacial Test-Screening Quality of Life (QOL) Questionnaire No consensus evaluation
Clinical examination of malocclusions Questionnaire regarding oral habits No consensus evaluation
Articulation test with phonetic analysis No consensus evaluation
Malocclusion measured with Dental Aesthetic Index Questionnaire No consensus evaluation
Methods
•
• • • •
• •
•
•
•
71% showed oral habits (habit group) Females prevalence of oral habits More affected sensory functions in habit group Results of the Nordic Orofacial test positively correlated with the questionnaire results Orofacal dysfunctions were associated with worse QOL
Higher prevalence of malocclusion at 3 years of age Significant relation between anterior open bite and posterior cross-bite and sucking habits
Correlations between articulation disorders, Class III occlusion, diastema, increase in overjet, and presence of open and deep bite
Missing teeth and the presence open bite: risk indicators for speech capability Molar relationship: risk indicator for chewing capability
Results
Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
485
Oral Diseases
Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
486
orthodontic treatment. In addition, relations between occlusal findings, and articulation characteristics and the oromyofunctional behavior are studied. Given the growing demands for perfect articulation in today’s communication-based society and the lack of specialized speech analysis studies of children seeking orthodontic services, additional research is warranted. Detailed information on speech and oromyofunctional characteristics in children seeking orthodontic treatment should lead to better multidisciplinary guidance of these patients and a better long-term outcome regarding dentofacial appearance and speech.
Methods and materials This study was approved by the human subject committee of the Ghent University (name: EC UZG, registration number 2013/761). Written informed consent was obtained from each participants’ parents.
Subjects All children were native speakers of Flemish, attended regular schools, and had no history of craniofacial anomalies, or presence of ear, nose, throat, or neurological pathologies. The original study group included 60 children (34 females and 26 males) with a mean age of 10.3 years (range: 7–12 years); they were consulting the Department of Orthodontics at the Ghent University. Ninety-three percent (52/56) of the children were consulting an orthodontist for the first time. Seven percent (4/56) had a functional appliance/activator (not used during speech assessment) (mean period: 12 months, range: 10–24 months). Nearly 11 percent (6/56) of the children were in the first translational period (early mixed dentition), 21% (12/56) were in the intertranslational period, 48% (27/56) were in the second translational period (late mixed dentition), and 20% (11/56) had permanent dentition. Four children were excluded on the day of testing due to temporary nasal obstruction caused by a nasal cold. The final study group included 56 children (32 females and 24 males) with a mean age of 10.2 years (range: 7–12 years). The gender- and age-matched control group, not undergoing or being referred for orthodontic treatment, was randomly selected and consisted of 54 Flemish-speaking subjects (29 females and 25 males) with a mean age of 9.3 years (range: 6–12 years). Nearly 4 percent (2/54) had a deciduous dentition, 37% (20/54) were in the first translational period (early mixed dentition), 48% (26/54) were in the translational period, and 11% (6/54) had permanent dentition. An independent Student’s t-test showed no significant age and gender differences between the subjects in the experimental group and those in the control group. In comparison with the control group, significantly more children in the study group (11%) were in the first translational period (early mixed dentition). Two orthodontists performed the intra- and extraoral orthodontic examinations. The types of malocclusions and dental clinical findings in the experimental group are mentioned in Table 2. To classify malocclusions, Angle’s taxonomy was used, with a subdivision in Class II malocclusions (Class II division with proclination of the upper front teeth and Class II division 2 with retroclination of the upper front teeth). Other functional disturbances (mandibular displacements) were noted as well as different occlusal parameters (overbite, overjet, cross-bite,. . .). Definitions and distribution are given in Table 2.
Table 2 Occlusal findings with definitions (Proffit et al, 1986) in the children seeking orthodontic treatment Dental relationship Class I Class II/1
Class II/2
Class III Mandibular displacement (forced bite) Absent To the left To the right Anteriorly Buccal cross-bite
Absent Unilateral Bilateral Anterior open bite
Absent Present Overjet Normal Increased Reduced Overbite Normal Reduced, edge to edge Reduced, negative Increased
Criteria/definition Angle’s classification for a normal relationship between upper and lower jaw Angle’s classification of a retruded mandible in regard to the maxilla with proclination of the upper front teeth Angle’s classification of a retruded mandible in regard to the maxilla with retroclination of the upper front teeth Angle’s classification of a protruded mandible in regard to the maxilla When closing from the rest position, the mandible displaces to avoid a premature contact into maximum interdigitation
Percentage (n) 32 (18/56) 52 (29/56)
16 (9/56)
0 (0/56)
87 (49/56) 4 (2/56) 7 (4/56) 2 (1/56) The buccal cusps of the lower premolars and/or molars occlude buccally to the buccal cusps of the upper premolars and/or molars 61 (34/56) 34 (19/56) 5 (3/56) The lower incisors do not occlude with the opposing upper incisors or the palatal mucosa when the buccal segment teeth are in occlusion 79 (44/56) 21 (12/56) Distance between the upper and lower incisors in the horizontal plane (mm) 2–4 mm More than 4 mm Less than 2 mm Vertical overlap of the upper and lower incisors when viewed anteriorly (mm) One-third to one-half coverage of the lower incisors No vertical overlap but the incisal edges of upper and lower incisors make contact No vertical contact between the incisors Greater than one-half coverage of the lower incisors
12 (7/56) 88 (49/56) 0 (0/56)
41 (23/56) 11 (6/56) 11 (6/56) 37 (21/56)
Methods
(Van der Meulen et al, 2008). A high score (on a scale ranging from 0 to 4) implies a high impact of the occlusion on speech characteristics.
Specific assessment techniques were used to determine speech characteristics (speech intelligibility and phonetic characteristics) and oromyofunctional behavior (Van Lierde et al, 2012).
Articulation and speech intelligibility
Oral health impact profile To determine the impact of the occlusion on speech characteristics, one question (‘did you experience any speech problem related to your teeth?’) of the Dutch version of the Oral Health Impact Profile (OHIP-14) was used
Oral Diseases
To assess articulation, speech samples were elicited by means of a picture-naming test. This test requires subjects to name black and white drawings of common objects and actions. It yields a speech sample, which contains instances of all Dutch single sounds, and most consonant clusters in all permissible syllable positions (see Appendix) (Van Lierde et al, 2001, 2011). The samples were recorded digitally for fur-
Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
ther analysis. The evaluation included a phonetic inventory and phonetic analysis. The phonetic inventory revealed which consonants and vowels the patient was capable of producing correctly in his/her native language. This analysis was conducted without making reference to the intended target sounds. A sound was considered to be present in the inventory when at least two instances of correct production (i.e. consistent with the standard realization of the sound) were found. In the relational analysis, consonant and vowel productions were compared with target productions and analyzed for error types on the segmental level. The speech samples collected by means of a picture-naming test were also used to judge overall speech intelligibility of words and sentences. An ordinal scale with four levels was used to rate speech intelligibility (0 = normal speech intelligibility, 1 = mildly impaired, 2 = moderately impaired, and 3 = severely impaired speech intelligibility). All analyses of articulation and intelligibility were based on a consensus narrow phonetic transcription made by two speech-language pathologists (L.B., E.F) using the symbols and diacritics of the International Phonetic Alphabet. Both speech-language pathologists were blinded to the subject’s condition, that is, whether a given subject belonged to the experimental or the control group. Moreover, the speech-language pathologists first simultaneously and independently transcribed the samples before comparing transcriptions and intelligibility ratings aiming at a consensus. Only spontaneous and unequivocal namings of the stimulus picture were retained in the analysis. The speech samples thus gathered consisted of 135 different words.
Oromyofunctional assessment During oromyofunctional assessments, five functions were verified as proposed in the protocol of Lembrechts et al (1999). These functions were as follows: lip function (lip position at rest, lip closure, dispersion of the corners of the mouth, lip protrusion, lip position during swallowing), tongue function (tongue position at rest, tongue protrusion, tongue retraction, tongue lifting against the upper lip, tongue depression against the lower lip, lateral movements of the tongue, tongue position during swallowing), blowing, sucking, and swallowing. There is an anterior interdental/addental tongue thrust when the tongue tip is between/against the central incisors. When the tongue blade is between the molars unilaterally or bilaterally, there is a unilateral or bilateral tongue thrust (Logemann, 2000; Pena-Brooks and Hedge, 2000). A three-point rating scale was used (0 = normal function, 1 = decreased function, 2 = severely disordered/function impossible). The following oromyofunctional disorders were verified: presence of sucking habits, drooling, mouth breathing, lip incompetence, and bruxism. The experienced speech-language pathologists first rated independently. In case of disagreement, the samples were replayed and discussed until a consensus was reached. A questionnaire regarding oral habits (thumb or finger sucking, pacifier sucking, mouth breathing, habitual open mouth posture, lip biting or sucking, drooling, bruxism, nail biting, tongue position at rest; unphysiological: tongue tip between or against the central incisors; normal: tongue tip at the upper or lower alveolar ridge) and swallowing was used.
Statistical analysis For the comparisons of overall satisfaction and the impact on speech in both groups, a Mann–Whitney U-test was performed. For the comparisons of the phonetic articulation characteristics and oromyofunctional disorders and to verify the associations between phonetic articulatory, oromyofunctional, and orthodontic disorders, Fisher’s exact test was used. All significance levels were set at P = 0.05.
Results Oral health impact profile The mean total OHIP score for the subjects seeking orthodontic treatment was 1.05 (s.d.: 1.15 range: 0–4). The mean total OHIP score for the control subjects was 0.4
(s.d.: 0.71 range: 0–1). The Mann–Whitney U-test showed a significantly increased impact of the occlusion on speech (P = 0.001) in the subjects seeking orthodontic treatment in comparison with the control subjects. No gender- and age-related differences in OHIP outcome were found.
487
Articulation and speech intelligibility The phonetic inventory was complete in all subjects of both groups (100% consensus evaluation). The results of the in-depth phonetic analysis (consensus evaluation 87%) are provided in Table 3. Phonetic articulation disorders of/s/,/n/,/l/,/t/,/d/,/p/,/b/, and/m/were found in the subjects seeking orthodontic treatment, with disorders of/s/,/n/,/l/, and/t/occurring significantly more often. The Mann–Whitney U-test revealed that children in the orthodontic group produced more phonetic disorders per child (P < 0.001) (mean number of phonetic disorders/child: 2.3 sounds, s.d.: 1.92, range: 0–5) in comparison with children without orthodontics (mean number of phonetic disorders/child: 0.9 sounds, s.d.: 1.51, range: 0–5). Normal speech intelligibility (100% consensus evaluation) was seen in both groups. Oromyofunctional behavior The types of oromyofunctional disorders in both groups are provided in Table 4. Significantly more children seeking orthodontic treatment showed an impaired lip position during swallowing (P = 0.006) and an impaired tongue function at rest (P < 0.001) in comparison with the control group children. Lip function at rest (P = 0.243), lip closure (P = 1.00), dispersion of the corners of the mouth (P = 0.082), and lip protrusion (P = 0.896) did not differ significantly in both groups. Moreover, no significant differences were found for tongue protrusion (P = 0.618), tongue retraction (P = 1.000), tongue lifting/depression (P = 0.482/P = 0.676), and lateral movements of the tongue (P = 0.266) between both groups. A Fisher’s exact test revealed a significant association between anterior tongue position at rest and tongue thrust or visceral swallowing pattern (P < 0.01). All children with a tongue thrust had an anterior tongue position at rest. No significant link was found between anterior tongue position at rest and persistent sucking behavior (P = 0.780). The types of oral habits (based on a questionnaire) in both groups are provided in Table 5. Significantly more control group children showed pacifier sucking (P = 0.026) in comparison with the children seeking orthodontic treatment. The latter group of children showed significantly more lip incompetence during breathing (P = 0.002), habitual open mouth posture (P < 0.001), lip sucking/biting (P = 0.002), anterior tongue position at rest (P < 0.01), and tongue thrust (P = 0.03) in comparison with the control group. No significant differences between both groups were found for thumb/finger sucking, drooling, bruxism, and nail biting. The children seeking orthodontic treatment (mean number of oral habits: 3.3, s.d.: 1.84, range: 0–7) showed significantly more (P < 0.001) oral habits than children in the control group (mean number of oral habits: 1.4, s.d.: 1.44, range: 0–5).
Oral Diseases
Speech, oral behavior, and orthodontic treatment
KM Van Lierde et al
488
Table 3 Type of phonetic articulation disorders with definitions (Pena-Brooks and Hedge, 2000) in children seeking orthodontic treatment (n = 56) and in children without further orthodontic treatment (n = 54). The level of significance (P-value, Fisher’s exact test) between the results of the children seeking orthodontic treatment and the children without further orthodontics is provided
Type of phonetic articulation disorder Sigmatism Sigmatism addentalis Sigmatism stridens Sigmatism simplex Sigmatism labiodentalis Sigmatism lateroflexus Sigmatism interdentalis Sigmatism palatalis Phonetic disorder of the/n/ Addental production of the/n/ Interdental production of the/n/ Lambdacism Lambdacism addentalis Lambdacism interdentalis Lambdacism lateroflexus Phonetic disorder of the/t/ Addental production of the/t/ Interdental production of the/t/ Tensed/t/ Phonetic disorder of the/d/ Addental production of the/d/ Interdental production of the/d/ Multiple interdental productions Multiple addental productions Phonetic disorder of the bilabials
Criteria/definition Phonetic disorder of the/s/ /s/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /s/sound accompanied with a whistle sound /s/sound without sufficient frication /s/sound is produced between the lower lip and the upper incisors (instead of between the central incisors) /s/sound with tongue tip against the canine tooth /s/sound with the tongue tip between the central incisors /s/sound with the tongue tip against the more posterior part of the palate /n/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /n/sound with the tongue tip between the central incisors Phonetic disorder of the/l/ /l/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /l/sound with the tongue tip between the central incisors /l/sound with the tongue tip against the canine tooth /t/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /t/sound with the tongue tip between the central incisors /t/sound followed by a slight/s/sound /d/sound with the tongue tip against the central incisors (instead of against the upper alveolus) /d/sound with the tongue tip between the central incisors Interdental production of/s/,/t/,/d/,/n/,/l/,/z/ Addental production of/s/,/t/,/d/,/n/,/l/,/z/ Phonetic disorder of the/p/,/b/,/m/
Children seeking orthodontics % (n)
Children without orthodontics % (n)
Level of significance P-value
59 (33/56) 25 (14/56)
22 (12/54) 4 (2/54)
