The Effect of Bimaxillary Orthognathic Surgery on Voice Characteristics in Skeletal Class 3 Deformity Patients: An Evaluation Using Acoustic Analysis

Impact of orthognathic surgery on voice and speech: a systematic review and meta-analysis

BACKGROUND

Orthognathic surgical procedures, whether in one or both jaws, can affect structures regarding the articulation and resonance of voice and speech.

OBJECTIVE

Evaluating the impact of orthognathic surgery on voice and speech performance in individuals with skeletal dentofacial disharmony.

SEARCH METHODS

Word combinations and truncations were adapted for the following electronic databases: EMBASE, PubMed/Medline, Scopus, Web of Science, Cochrane Library, and Latin American and Caribbean Literature in Health Sciences (LILACS), and grey literature.

SELECTION CRITERIA

The research included studies on nonsyndromic adults with skeletal dentofacial disharmony undergoing orthognathic surgery. These studies assessed patients before and after surgery or compared them with individuals with good facial harmony using voice and speech parameters through validated protocols.

DATA COLLECTION AND ANALYSIS

Two independent reviewers performed all stages of the review. The Joanna Briggs Institute tool was used to assess risk of bias in the cohort studies, and ROBINS-I was used for nonrandomized clinical trials. The authors also performed a meta-analysis of random effects.

RESULTS

A total of 1163 articles were retrieved after the last search, of which 23 were read in full. Of these, four were excluded, totalling 19 articles for quantitative synthesis. When comparing the pre- and postoperative periods, both for fundamental frequency, formants, and jitter and shimmer perturbation measures, orthognathic surgery did not affect vowel production. According to the articles, the main articulatory errors associated with skeletal dentofacial disharmonies prior to surgery were distortions of fricative sounds, mainly/s/ and/z/.

CONCLUSIONS

Orthognathic surgery may have little or no impact on vocal characteristics during vowel production. However, due to the confounding factors involved, estimates are inconclusive. The most prevalent articulatory disorders in the preoperative period were distortion of the fricative phonemes/s/ and/z/. However, further studies must be carried out to ensure greater robustness to these findings.

REGISTRATION

PROSPERO (CRD42022291113).

Impact of 3-dimensional anatomical changes secondary to orthognathic surgery on voice resonance and articulatory function: a prospective study

An evaluation was made of the impact of orthognathic surgery (OS) on speech, addressing in particular the effects of skeletal and airway changes on voice resonance characteristics and articulatory function. A prospective study was carried out involving 29 consecutive patientssubjected to OS. Preoperative, and short and long-term postoperative evaluations were made of anatomical changes (skeletal and airway measurements), speech evolution (assessed objectively by acoustic analysis: fundamental frequency, local jitter, local shimmer of each vowel, and formants F1 and F2 of vowel /a/), and articulatory function (use of compensatory musculature, point of articulation, and speech intelligibility). These were also assessed subjectively by means of a visual analogue scale. Articulatory function after OS showed immediate improvement and had further progressed at one year of follow up. This improvement significantly correlated with the anatomical changes, and was also notably perceived by the patient. On the other hand, although a slight modification in vocal resonance was reported and seen to correlate with anatomical changes of the tongue, hyoid bone, and airway, it was not subjectively perceived by the patients. In conclusion, the results demonstrated that OS had beneficial effects on articulatory function and imperceptible subjective changes in a patient's voice. Patients subjected to OS, apart from benefitting from improved articulatory function, should not be afraid that they will not recognise their voice after treatment.

Vowel sound production and its association with cephalometric characteristics in skeletal Class III subjects

BACKGROUND

This study aimed to evaluate differences in vowel production using acoustic analysis in skeletal Class III and Class I Japanese participants and to identify the correlation between vowel sounds and cephalometric variables in skeletal Class III subjects.

MATERIALS AND METHODS

Japanese males with skeletal Class III (ANB < 0°) and Class I skeletal anatomy (0.62° < ANB < 5.94°) were recruited (n = 18/group). Acoustic analysis of vowel sounds and cephalometric analysis of lateral cephalograms were performed. For sound analysis, an isolated Japanese vowel (/a/,/i/,/u/,/e/,/o/) pattern was recorded. Praat software was used to extract acoustic parameters such as fundamental frequency (F0) and the first four formants (F1, F2, F3, and F4). The formant graph area was calculated. Cephalometric values were obtained using ImageJ. Correlations between acoustic and cephalometric variables in skeletal Class III subjects were then investigated.

RESULTS

Skeletal Class III subjects exhibited significantly higher/o/F2 and lower/o/F4 values. Mandibular length, SNB, and overjet of Class III subjects were moderately negatively correlated with acoustic variables.

LIMITATIONS

This study did not take into account vertical skeletal patterns and tissue movements during sound production.

CONCLUSION

Skeletal Class III males produced different /o/ (back and rounded vowel), possibly owing to their anatomical positions or adaptive changes. Vowel production was moderately associated with cephalometric characteristics of Class III subjects. Thus, changes in speech after orthognathic surgery may be expected. A multidisciplinary team approach that included the input of a speech pathologist would be useful.

What Is the Effect of Maxillary Impaction Orthognathic Surgery on Voice Characteristics? A Quasi-Experimental Study

Background

Regarding the impact of orthognathic surgery on the airway and voice, this study was carried out to investigate the effects of maxillary impaction surgery on patients' voices through acoustic analysis and articulation assessment.

Methods

This quasi-experimental, before-and-after, double-blind study aimed at examining the effects of maxillary impaction surgery on the voice of orthognathic surgery patients. Before the surgery, a speech therapist conducted acoustic analysis, which included fundament frequency (F0), Jitter, Shimmer, and the harmonic-to-noise ratio (HNR), as well as first, second, and third formants (F1, F2, and F3). The patient's age, sex, degree of maxillary deformity, and impaction were documented in a checklist. Voice analysis was repeated during follow-up appointments at one and six months after the surgery in a blinded manner. The data were statistically analyzed using SPSS 23, and the significance level was set at 0.05.

Results

Twenty two patients (18 females, 4 males) were examined, with ages ranging from 18 to 40 years and an average age of 25.54 years. F2, F3, HNR, and Shimmer demonstrated a significant increase over the investigation period compared to the initial phase of the study (P <0.001 for each). Conversely, the Jitter variable exhibited a significant decrease during the follow-up assessments in comparison to the initial phase of the study (P< 0.001).

Conclusion

Following maxillary impaction surgery, improvements in voice quality were observed compared to the preoperative condition. However, further studies with larger samples are needed to confirm the relevancy.