orthodontics

Speech and Malocclusion #Paper1

Anisha ValliLeave a comment

Introduction

Orthodontic care primarily focuses on dental esthetics and masticatory function, but its impact on sound production is often overlooked. Sound production involves a dynamic interaction with the oral cavity, requiring orthodontists to recognize how dental anomalies and treatments influence speech. Enhanced patient care can be achieved through better treatment planning and referrals to speech pathologists for patients whose malocclusions affect speech production. This is particularly relevant for adults requiring proper speech for professional purposes.

Definition of Sound and Speech Mechanism

Sound is mechanical vibration energy requiring the coordination of neural, muscular, mechanical, aerodynamic, acoustic, and visual elements. Speech production involves four processes:

  1. Language processing in the brain.
  2. Motor command generation to vocal organs.
  3. Articulatory movements of the oral cavity.
  4. Air emission from the lungs.

Speech sounds are classified into:

  • Vowels: Produced without obstruction to airflow.
  • Consonants: Produced with varying obstructions in oral or nasal cavities.

Classification

  • Ingram’s Classification:
    1. Dysphonia: Disorders of vocalization.
    2. Dysrhythmia: Respiratory coordination issues.
    3. Dysarthria:
      • Due to neurological abnormalities (e.g., motor neuron lesions).
      • Due to local abnormalities (e.g., jaws, teeth, palate).
    4. Non-Structural Disorders: Mental, hearing, or environmental factors.
    5. Developmental Disorders: Abnormal or delayed speech development.
    6. Mixed Disorders: Combination of the above.
  • Types of Consonants:
    • Bilabial consonants: “b”, “p”, “m”
    • Labiodental consonants: “f ”, “v”
    • Dental consonants: “d”, “t”, “n”, “s”, “z”
    • Dentoalveolar consonants: “c”, “c”, “j”, “ş”
    • Frontopalatal consonants: “g”, “k”, “l”, “r”, “y” 
    • Backpalatal consonants: “g”, “ğ”
    • Pharyngeal consonant: “h”
    • Nasal consonants: “m”, “n”

Orthodontic Implications

  • Malocclusion and Speech:
    • Class II Malocclusion:
      • Difficulty with bilabial sounds (“p,” “b,” “m”).
      • Compensatory mechanisms involve lower lip contacting maxillary incisors.
    • Class III Malocclusion:
      • Difficulty with labiodental sounds (“f,” “v”).
      • Common errors include bilabial production or reversed labiodental posture.
      • Dentalization leads to lisping for sounds like “t,” “d,” “s,” and “z.”
    • Open Bite:
      • Anterior lisping and distortion of anterior sounds.
      • Severe cases show more misarticulations when combined with other anomalies.
    • Diastema:
      • Impacts sounds like “l,” “n,” and “d.”
  • Velopharyngeal Dysfunction: Associated with cleft palate, causing hypernasal resonance and airflow issues.
  • Adaptation Mechanisms: Tongue and lips often adapt to dental irregularities, masking speech defects.

Studies

  • Fymbo’s Study:
    • Analyzed 410 students, noting a higher incidence of speech difficulties in those with malocclusion.
    • Severity of speech defects correlated with the severity of dental anomalies.
  • Laine et al.:
    • Narrower palates linked to sibilant speech disorders.
    • Increased open bite and overjet have greater impacts than spacing.
  • Dalston and Vig:
    • Minimal long-term speech changes post-orthognathic surgery.
  • Garber et al.:
    • Temporary speech errors observed post-surgery resolved within 1-3 months.

Shortcomings

  • Limited Longitudinal Data: Lack of extended studies tracking speech changes post-treatment.
  • Standardization Issues: No universal methods to measure malocclusion-related speech defects.
  • Complex Etiology:
    • Speech defects often result from multiple factors, not just malocclusion.
    • Adaptation varies based on intelligence, emotional state, and muscle control.

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