Which specific malocclusion feature, when corrected in adulthood, has the highest likelihood of showing a statistically significant improvement in phonetic articulation (e.g., elimination of a frontal lisp) according to speech pathology studies?

 # Which specific malocclusion feature, when corrected in adulthood, has the highest likelihood of showing a statistically significant improvement in phonetic articulation (e.g., elimination of a frontal lisp) according to speech pathology studies?

A. Maxillary incisor protrusion with anterior open bite (Interdental gap)

B. Unilateral posterior crossbite

C. Severe class II division 2 deep bite

D. Mild crowding of the mandibular anterior teeth

The correct answer is A.  Maxillary incisor protrusion with anterior open bite (Interdental gap)

The malocclusion feature correction that shows the highest likelihood of a statistically significant improvement in phonetic articulation (e.g., elimination of a frontal lisp) in adulthood is: Maxillary incisor protrusion with anterior open bite (Interdental gap)



Rationale from Speech Pathology Studies

The correction of a malocclusion that eliminates an anterior open bite and reduces excessive maxillary incisor protrusion (overjet) is the most consistently linked orthodontic correction to an improvement in speech.

1. Direct Cause of Lisps

A frontal lisp (or interdental lisp), which involves the tongue protruding between the front teeth during production of the /s/ and /z/ sounds, is often a compensatory mechanism for an interdental gap (anterior open bite) or a large overjet (protrusion). The absence of the anterior dental barrier forces the tongue to find another point of articulation, which leads to the distorted sounds.

2. Evidence in Adults

Speech pathology studies have found a statistically significant association between the severity of an anterior open bite (often cited as an open bite greater than 2 mm) and the occurrence of speech sound errors, particularly with the sibilant sounds /s/ and /z/. By correcting the open bite and reducing the protrusion through orthodontic treatment (often in conjunction with myofunctional therapy), the physical space is closed, restricting the tongue's forward movement and creating the necessary physical target for correct articulation, which directly and reliably improves the articulation errors.

The other options are less likely to produce a significant, consistent phonetic improvement in the adult:

Unilateral posterior crossbite: Primarily affects chewing (mastication) and is less directly linked to common anterior speech sounds like /s/ and /z/.

Severe class II division 2 deep bite: While a deep bite can affect function, it typically does not create an anterior gap that causes the tongue to thrust forward, thus its link to frontal lisps is much weaker.

Mild crowding of the mandibular anterior teeth: This is primarily an aesthetic and periodontal issue. The subtle misalignment of the lower teeth does not usually create the structural deficit necessary to cause a major articulation error like a lisp.