Effects of fixed labial and lingual orthodontic appliances on speech sound production: A comparative in vivo study

Introduction: The eventual esthetic solution for patients who do not want visible orthodontic appliance is the lingual orthodontic appliance. The result produced by the lingual orthodontic appliance is parallel to those produced by the labial orthodontic appliance. However, there is an articulation problem due to the position of the lingual brackets as there is a modification of the lingual surface of the teeth. Speech problems with each appliance are studied individually and extensively, but the comparison of both appliances regarding speech is very scanty. Aim: The aim of this study is to evaluate the effect of fixed labial and lingual orthodontic appliance on speech sound production at a different time interval. Materials and methods: A total number of 30 patients were included in this study, 15 patients were bonded with the fixed labial appliance (Group 1) and 15 patients were bonded with the fixed self-ligating lingual appliance (Group 2). Based on four types of errors (E1, E2, E3, E4), a total of nine groups of sounds (S1, S2, S3, S4, S5, S6, S7, S8, S9) were evaluated for each audiovisual sample at four different time intervals (T1, T2, T3, T4) by two different speech therapist individually in each group. Results: A high degree of agreement was found between the two observers in both groups regarding the type of sound effected and the type of error during sound production. The total number of patients with effected speech is more in the lingual group compared to the labial group on the same day of bonding until six months in treatment. Conclusion: The results of the present study demonstrated the following, the total number of patients with lingual appliance had more errors in speech compared to the labial appliance at the beginning of the treatment. Patients with lingual appliance required more time for adaptation concerning speech. A similar group of sounds was effected in both types of an appliance with a similar type of error. Patients with labial appliance showed more comfort and easier adaptation with the appliance. The anatomical location of the appliance plays an important role in speech alteration and adaptation. These findings should be considered before selecting an appliance for a particular patient. Corresponding Author: Dansih Intesaab Ahmed Department Of Orthodontics and Dentofacial Orthopaedics, M.A.Rangoonwala College of Dental Sciences & Research Centre, Pune-1, India e-mail:intesaab_001@yahoo.com Effects of fixed labial and lingual orthodontic appliances on speech sound production: A comparative in vivo study INTRODUCTION A complex psycho-physiological process for putting thoughts into words and organizing these words into a sequence with grammatical context is called speech. The physiological media of speech are respiratory, phonatory and articulation. The teeth, in combination with the lips and tongue, play an important role in the articulation of consonants by airflow obstruction and modifications. Therefore tooth position may play a role in articulatory speech disorders.1 More and more professional adults are seeking orthodontic treatment in this era; the orthodontist needs to recognize and to determine the possible risk factors affecting communication integrity. It is eminent that adults have an unenthusiastic reaction towards the esthetics of conventional fixed labial orthodontic appliances Submitted: September 7, 2019; Revised: October 7, 2019; Published: October 24, 2019 Ahmed DI., Kalia A., Nene S., Joshi J., Adsure G. Effects of fixed labial and lingual orthodontic appliances on speech sound production: A comparative in vivo study. South Eur J Orthod Dentofac Res. 2019;6(2):27-34. South Eur J Orthod Dentofac Res Ahmed DI et al. Effects of orthodontic appliances on speech sound production 28 and want to hide them. Recent advances such as plastic and ceramic bracket and esthetics archwires are available in the market, but the definitive solution to the problem mentioned above is the placement of the brackets on the lingual surface of the teeth.2 The solution for the esthetic problem due to the labial orthodontic appliance is the development of lingual orthodontic appliances. The final results of the lingual appliance are as good as the labial appliance.3-6 Since the lingual surface of the teeth is altered due to the placement of the lingual brackets, which may often cause articulation problems.7-11 The other issues reported to the lingual appliance is oral discomfort, difficulty in chewing, and tongue irritation.12-15 The issues mentioned above may lead to the social embarrassment that is greater than that originating from visible labial brackets.16 Studies regarding the individual comparison of both the appliances concerning the discomfort during the therapy are ample, but comparison among the two are very few.11-15 However, the intensity and extent of oral discomfort caused by lingual appliances compared to that caused by labial appliances are not intelligible yet. To date, there is no published study comparing speech performance between labial and lingual fixed orthodontic treatment that employed acoustic analysis and sonography. Additionally, all of these studies comparing levels of discomfort and speech performance between the two treatment modalities have failed to allot patients to groups randomly (i.e., selection bias may have been present in these investigations).3-15 The goal of this study was to compare the effect of sound speech production between the fixed labial and lingual appliance. MATERIALS AND METHODS This study consisted of total 30 patients of Class I bimaxillary protrusion malocclusion, from which 15 were being treated with labial fixed orthodontics appliance and 15 patients were being treated with lingual fixed orthodontics appliance in the Department of Orthodontics and Dentofacial Orthopaedics. (M.A Rangoonwala dental college and research center, Pune, India). This research was approved by ethical committee of University (Maharashtra university of health and science, Nasik, India) and Faculty (M.A Rangoonwala dental college and research center, Pune, India). Group 1 labial fixed orthodontic appliance bracket system 0.022 slot (American orthodontics) Master/mini series. Group 2 lingual fixed orthodontics appliances self ligating bracket system 0.018 slot (Classic orthodontics). Inclusion criteria 1. Class I bimaxillary protrusion malocclusion patients who were undergoing fixed labial orthodontic appliance therapy. 2. Class I bimaxillary protrusion malocclusion patients who were undergoing fixed lingual orthodontic appliance therapy. 3. Patients selected were studying or had completed education from a school where the medium of educations is english. (All the subjects were screened and had no mother tongue influence on english language while reading). Exclusion criteria 1. Overt dysmorphology such as cleft lip and/or palate. 2. Neurological disorders. 3. Tongue thrust habits. 4. Hearing deficits. (Subjective analysispatient could follow conversation over 2-5 feet distance without a problem). 5. Prior orthodontic treatment. 6. History of speech or hearing therapy. Method of data collection 1. The microphone was mounted on the DSLR camera, then camera was mounted on the tripod. The patient was asked to sit on a chair against a white background 4 feet away from the camera which was on auto focus. The recording was taken in a sound proof room. (Figure 1) 2. A printed poster with pictures and words to be evaluated in bold font was mounted on a stand at a distance of one and half feet from the patient, the mounted poster helped the patient in maintaining an upright natural head position and a parallel Frankfort horizontal plane. (Figure 1, 2) 3. The patient was instructed to read out the poster, and a video with sound was taken (T1) (Figure 3) Figure 1. DSLR camera with recording microphone mounted on the tripod against the white background. South Eur J Orthod Dentofac Res Ahmed DI et al. Effects of orthodontic appliances on speech sound production 29 4. Depending upon the choice of appliance decided for the patient, the appliance was bonded on both the dental arch using the 37% orthophosphoric acid, bonding agent and adhesive. The method of bonding was direct for both appliances. Then a 0.012 NiTi wire was placed in the both dental arch at the same appointment. (Figure 4a, 4b, 5). 5. Individual ligation was done for the labial appliance with ligature wire. As the lingual appliance was self ligating no ligature wire was used. 6. With the exact same setup again the video audio recording was taken with same poster (T2). 7. After three months 0.014 NiTi wire was placed in both dental arches with the same materials and technique. Again a recording with the same setup was taken (T3). 8. After 6 months into orthodontic treatment patient was recalled and 0.016 NiTi wire was placed in both the dental arches. Recording was again taken at this point (T4). 9. All the recordings in sequence of T1, T2, T3, T4 were stored in a folder with the specific patient serial number on it. (Figure 6) 10. In every recording the eyes of the subjects were hidden digitally with a black strip, to hide the identity of the patient. 11. Individually the speech therapist examined each of the recording carefully using windows media player (Figure 7), and evaluated each of them on the chart prepared for that particular patient with the serial number matching the folder. Both the speech therapist were not aware of the age, sex, or the type of appliance used for that particular patient. Figure 2. Printed posters with pictures and words. Figure 3. Patient reading the given paper with words and DSLR recording the audio video clip on auto focus. Figure 4a. Lingual appliance bonded on the teeth. Figure 4b. Labial appliance bonded on the teeth. South Eur J Orthod Dentofac Res Ahmed DI et al. Effects of orthodontic appliances on speech sound production 30 12. Both speech therapist did the analysis at