The effects of rapid maxillary expansion on voice function

Can rapid maxillary expansion affect speech sound production in growing patients? A systematic review

Rapid maxillary expansion (RME) may change speech sound parameters due to the enlargement of oral and nasal cavities. This study aimed to systematically review the current evidence on speech changes as a side effect of RME. An electronic search was conducted in nine databases, and two of them accessed the 'grey literature'. The eligibility criteria included clinical studies assessing orthodontic patients with maxillary transverse deficiency and the relationship with speech alterations without restricting publication year or language. Only interventional studies were included. The JBI Critical Appraisal Tool assessed the risk of bias. The initial search provided 4853 studies. Seven articles (n = 200 patients) met the inclusion criteria and were analysed. The primary source of bias was the absence of a control group in four studies. RME altered speech production by changing vowel fundamental frequency and fricative phoneme formant frequency. Shimmer and jitter rates changed in one and two studies, respectively. Two studies presented deterioration during orthodontic treatment, but speech improved after appliance removal. Despite the limited evidence, RME affects speech during and after treatment.

Rapid Maxillary Expansion (RME): An Otolaryngologic Perspective

Background. To evaluate the possible effects of Rapid Maxillary Expansion (RME), such as nasal breathing problems, middle ear function, Obstructive Sleep Apnea (OSA) in the otolaryngology field. RME has already been introduced in orthodontics to expand the maxilla of young patients affected by transversal maxillary constriction. Methods. A literature search was performed using different databases (Medline/PubMed, EMBASE, and CINAHL), from May 2005 to November 2021, according to the PRISMA guidelines. Results. The application of RME in children has shown good results on nasal function, reducing nasal resistances, independently from a previous adenotonsillectomy. These results are not only related to the increasing of nasal transverse diameters and volume, but also to the stiffening of airway muscles, enabling the nasal filtrum function and avoiding mouth opening, thereby decreasing respiratory infections. Positive effects have also been reported for the treatment of conductive hearing loss and of OSA, with the reduction of Apnea Hypopnea Index (AHI), possibly due to (i) an increased pharyngeal dimensions, (ii) a new tongue posture, and (iii) reduced nasal respiratory problems. Conclusions. Otolaryngologists should be aware of the indications and benefits of the RME treatment, considering its possible multiple beneficial effects.

The Impact of Fan-Type Rapid Palatal Expanders on Speech in Patients With Unilateral Cleft Lip and Palate

Rapid palatal expanders (RPEs) are commonly used in patients with cleft lip and palate (CLP) prior to secondary alveolar bone grafting (SABG). Their position and size can impede tongue movement and affect speech. This study assessed changes in perception and production of speech over the course of RPE treatment.

Prospective longitudinal.

Tertiary university-affiliated hospital.

Twenty-five patients with unilateral CLP treated with Fan-type RPEs, and their parents.

Patient and parent speech questionnaires and patient speech recordings were collected at baseline before RPE insertion (T1), directly after RPE insertion (T2), during RPE expansion (T3), during RPE retention (T4), directly after RPE removal but before SABG (T5), and at short-term follow-up after RPE removal and SABG (T6).

Ratings for patient and parent questionnaires, first (F1) and second (F2) formants for vowels /a/, /i/, and /u/, and nasalance scores for non-nasal and nasal sentences, were obtained and analyzed using mixed model analyses of variance.

Ratings worsened at T2. For the vowel /a/, F1 and F2 were unchanged at T2. For the vowel /i/, F1 increased and F2 decreased at T2. For the vowel /u/, F1 was unchanged and F2 decreased at T2. Nasalance was unchanged at T2. All outcome measures returned to T1 levels by T4.

RPE insertion resulted in initial adverse effects on speech perception and production, which decreased to baseline prior to removal. Information regarding transient speech dysfunction and distress may help prepare patients for treatment.

Voice changes after surgically assisted rapid maxillary expansion

INTRODUCTION

This study aimed to investigate voice changes in patients who had surgically assisted rapid maxillary expansion (SARME).

METHODS

Nineteen adult patients with maxillary transverse deficiency were asked to pronounce the sounds "[a], [ϵ], [ɯ], [i], [ɔ], [œ] [u], [y]" for 3 seconds. Voice records were taken before the expansion appliance was placed (T0) and 5.8 weeks after removal (T1, after 5.2 months of retention). The same records were taken for the control group (n = 19). The formant frequencies (F0, F1, F2, and F3), shimmer, jitter, and noise-to-harmonics ratio (NHR) parameters were considered with Praat (version 6.0.43).

RESULTS

In the SARME group, significant differences were observed in the F1 of [a] (P = 0.005), F2 of [ϵ] (P = 0.008), and [œ] sounds (P = 0.004). The postexpansion values were lower than those recorded before. In contrast, the F1 of [y] sound (P = 0.02), F2 of [u] sound (P = 0.01), the jitter parameter of [ɯ] and [i] sounds (P = 0.04; P = 0.002), and the NHR value of [ϵ] sound (P = 0.04) were significantly than the baseline values. In the comparison with the control group, significant differences were found in the F0 (P = 0.025) and F1 (P = 0.046) of the [u] sound, the F1 of the [a] sound (P = 0.03), and the F2 of the [ϵ] sound (P = 0.037). Significant differences were also found in the shimmer of [i] (P = 0.017) and [ɔ] (P = 0.002), the jitter of [ϵ] (P = 0.046) and [i] (P = 0.017), and the NHR of [i] (P = 0.012) and [ɔ] (P = 0.009).

CONCLUSION

SARME led to significant differences in some of the acoustics parameters.

Influence of pontic design on speech with an anterior fixed dental prosthesis: A clinical study and finite element analysis

STATEMENT OF PROBLEM

Patients may experience disturbed articulation after treatment with a fixed dental prosthesis. However, studies that assess the relationship between fixed dental prosthesis design and the accuracy of speech sound production are lacking.

PURPOSE

The purpose of this clinical and finite element analysis (FEA) study was to examine the influence of pontic design on speech with anterior fixed dental prostheses.

MATERIAL AND METHODS

First, an articulation test was carried out in which a partially edentulous participant was required to pronounce 4 Chinese words containing the voiceless fricative/s/while wearing fixed dental prostheses with 2 types of pontic designs. The oral morphology was obtained by cone beam computed tomography (CBCT) scanning while the participant, wearing the 2 fixed dental prosthesis designs, was pronouncing the voiceless fricative/s/sound. The geometry of the oral cavity was then reconstructed by an image processing software program. Finally, a finite element model for sound wave propagation inside the oral cavity was developed within the framework of the finite element analysis software program. By using this model, the sound pressure level of the 2 types of pontic design was characterized and quantified under different fundamental frequencies (F₀). The data were analyzed with 1-way ANOVA (α=.05).

RESULTS

The experimental articulation test reported that the pontic design of fixed dental prostheses affected the speech production of the/s/sound (P<.001). The numerical study reported that the sound pressure level values were different under various fundamental frequencies. In addition, the pontic design of fixed dental prostheses affected the sound pressure level values, and the differences varied significantly from 420 to 1300 Hz (P<.05); however, the differences were not significant between 120 and 420 Hz (P>.05). Moreover, further comparisons of low F₀ (120 to 500 Hz), medium F₀ (520 to 900 Hz), and high F₀ (920 to 1300 Hz) reported that the differences in the medium F₀ area were most obvious (P<.001 for maximum sound pressure level value and P=.001 for sound pressure level value at Point Q).

CONCLUSIONS

Both the fixed dental prosthesis pontic design and the fundamental frequency could affect the sound field distribution.

Effects of maxillary expansion on hearing and voice function in non-cleft lip palate and cleft lip palate patients with transverse maxillary deficiency: a multicentric randomized controlled trial

INTRODUCTION

The association between the treatment of transverse maxillary deficiency and the recovery of hearing and voice functions has gained attention in recent years.

OBJECTIVE

This prospective controlled trial aimed to evaluate the effects of rapid maxillary expansion on hearing and voice function in children with non-cleft lip palate and bilateral cleft lip palate with transverse maxillary deficiency METHODS: 53 patients (26 non-cleft and 27 bilateral cleft lip palate; mean age, 11.1±1.8 years) requiring rapid maxillary expansion for correction of narrow maxillary arches were recruited for this trial. Eight sub-groups were established based on the degree of hearing loss. Pure-tone audiometric and tympanometric records were taken for each subject at four different time periods. The first records were taken before rapid maxillary expansion (T0), the second after expansion (T1) (mean, 0.8 months), the third after three months (T2) (mean, 3 months) and the fourth at the end of retention period (T3) (mean, 6 months). ANOVA and Tukey HSD post-hoc tests were used for data analysis. Additionally, voice analysis was done using an updated PRAAT software program in a computerized speech lab at T0 and T2. A paired-samplet-test was used for comparisons of mean values of T0 and T2 voice parameters within both groups.

RESULTS

Rapid maxillary expansion treatment produced a significant increase in the hearing levels and middle ear volumes of all non-cleft and bilateral cleft lip palate patients with normal hearing levels and with mild conductive hearing loss, during the T0-T1, T1-T2, T0-T2, and T0-T3 observation periods (p<0.05). The significant increase was observed in right middle ear volumes during the T0-T1, T0-T2 and T0-T3 periods in non-cleft patients with moderate hearing loss. For voice analysis, significant differences were observed only between the T0 and T2 mean fundamental frequency (F0) and jitter percentage (p<0.05) in the non-cleft group. In the cleft group, no significant differences were observed for any voice parameter between the T0 and T2 periods.

CONCLUSION

Correction of the palatal anatomy by rapid maxillary expansion therapy has a beneficial effect on both improvements in hearing and normal function of the middle ear in both non-cleft and bilateral cleft lip palate patients. Similarly, rapid maxillary expansion significantly influences voice quality in non-cleft patients, with no significant effect in BCLP patients.

Transverse Skeletal Effects of Rapid Maxillary Expansion in Pre and Post Pubertal Subjects: A Systematic Review

OBJECTIVE

The aim of this systematic review was to assess the transverse skeletal effects of rapid maxillary expansion (RME) in pre and post-pubertal subjects.

MATERIAL AND METHODS

Five databases were searched till May 2018; Pubmed, Cochrane, Scopus, Lilacs and Web of science in addition to the manual search of other sources. There were no language restrictions. Methodological Index for Non-Randomized Studies MINORS was used to assess the quality and risk of bias of the trials included.

RESULTS

Six studies were finally included in the qualitative analysis. A meta-analysis wasn't performed due to the heterogeneity of methodologies and outcomes. All of the included studies showed drawbacks in their structure yielding weak evidence. On the short term, RME caused an increase in the maxillary and lateral-nasal widths in pre-pubertal subjects by 3.4 mm and 3.3 mm, and by 2.8 and 2.2 mm respectively in post-pubertal subjects. Although statistically insignificant, the maxillary width increase was more than that of the post-pubertal subjects by 0.6 mm. Over the long term, expansion produced permanent increases in the transverse dimensions of both the dento-alveolar and skeletal components of the maxilla and circum-maxillary structures in pre-pubertal subjects. The post-pubertal subjects presented with a statistically significant increase only in the later-nasal width by 1.3 mm than the untreated controls with no permanent increase in the skeletal maxillary width.

CONCLUSION

The literature is very deficient regarding the use of skeletal age as a reference in the treatment of skeletal crossbites using RME. Only weak evidence exists supporting the increased maxillary and lateral-nasal widths after tooth-tissue borne RME in pre-pubertal subjects, with these effects being less in the post-pubertal ones.

Relationship between voice function and skeletal effects of rapid maxillary expansion

OBJECTIVE

To evaluate the effects of rapid maxillary expansion (RME) on the vocal quality, maxillary central incisors, midpalatal suture, and nasal cavity in patients with maxillary crossbite.

MATERIALS AND METHODS

Coronal CT scans of 30 subjects (14 boys, 16 girls; mean age, 12.01 ± 0.75) were taken before RME (T0), and at the end of the expansion phase (T1). Voice samples of all patients were recorded with a high-quality condenser microphone (RODE NT2-A) on a desktop computer at T0 and T1. Statistical analyses were performed using a paired-sample t-test. The degree of association between the changes in the voice parameters and nasal width was assessed with Pearson's correlation.

RESULTS

RME treatment produced a significant increase in the transverse dimensions of the midpalatal suture and nasal cavity between T0 and T1 ( P < .05). The maximum F0 and jitter (%) results were shown to decrease statistically significantly from T0 to T1 ( P < .001 and P = .042, respectively). Between T0 and T1, shimmer (%) and shimmer (dB) exhibited statistically significant increases ( P = .037 and P = .019, respectively).

CONCLUSIONS

After RME therapy, voice quality differences were found to be associated with increases in nasal width.

Evaluation of the stiffness characteristics of rapid palatal expander screws

Background

The aim of this study is to evaluate the mechanical properties of the screws used for rapid expansion of the upper jaw.

Methods

Ten types of expansion screw were assessed, seven with four arms: Lancer Philosophy 1, Dentaurum Hyrax Click Medium, Forestadent Anatomic Expander type “S”, Forestadent Anatomic Expander type “S” for narrow palates, Forestadent Memory, Leone A 2620-10 with telescopic guide, and Leone A 0630-10 with orthogonal arms; and three with two arms: Dentaurum Variety S.P., Target Baby REP Veltri, and Leone A 362113. A test expander with the mean dimensions taken from measurements on a sample of 100 expanders was constructed for each screw. The test expanders were connected to the supports of an Instron 4467 (Instron Corp., USA) mechanical testing machine equipped with a 500 N load cell, and the compression force exerted after each activation was measured. The mean forces expressed by the two- and four-arm expanders were then compared.

Results

After five activations, the forces expressed by the two-arm devices were double than those expressed by the four-arm devices on average (224 ± 59.9 N vs. 103 ± 32.9 N), and such values remained high after subsequent activations.

Conclusions

The expanders tested demonstrated stiffness characteristics compatible with opening of the palatine sutures in pre-adolescent patients. The stiffness of such devices can be further increased during the construction phase.