Which dentofacial morphology is generally considered the highest risk factor for the development or exacerbation of Obstructive Sleep Apnea (OSA) in adults?

 # Which dentofacial morphology is generally considered the highest risk factor for the development or exacerbation of Obstructive Sleep Apnea (OSA) in adults?

A. Deep Bite Class II Division 2 with an average mandibular plane angle

B. High Angle Class II with marked Mandibular Retrognathia

C. High Angle Class III with Anterior Crossbite

D. Low Angle Class I with severe dental crowding

B. High Angle Class II with marked Mandibular Retrognathia

High-angle Class II malocclusion, characterized by a steep mandibular plane angle (indicating a vertical growth pattern) and significant mandibular retrognathia (receded lower jaw), is a major anatomical risk factor for OSA in adults. This morphology reduces pharyngeal airway space by positioning the hyoid bone and tongue base posteriorly, promoting airway collapse during sleep—exacerbated by the dolichofacial pattern's narrower transverse dimensions. Studies confirm this combination correlates with decreased upper airway volume and higher OSA severity compared to other skeletal patterns. In contrast, Class II Division 2 (A) often features a lower or average angle with less retrognathia impact; high-angle Class III (C) typically widens the airway via mandibular prognathism, offering protection; and low-angle Class I (D) with crowding presents minimal skeletal compromise to airway patency.

A functional lateral shift of the mandible into maximum intercuspation is most likely to be associated with which long-term consequence if left uncorrected during the active growth period?

 # A functional lateral shift of the mandible into maximum intercuspation is most likely to be associated with which long-term consequence if left uncorrected during the active growth period?

A. Increased risk of External Apical Root Resorption (EARR)

B. Pathologic Attrition on the non-shifted side

C. Anterior Open Bite Development

D. Skeletal Asymmetry

The correct answer is D. Skeletal Asymmetry

A functional lateral shift of the mandible—often due to unilateral posterior crossbite—forces the jaw to deviate laterally into maximum intercuspation to avoid occlusal interferences. During active growth, this chronic deviation alters condylar loading and remodeling, promoting asymmetric mandibular growth (e.g., longer ramus or body on the shifted side) and potential facial skeletal discrepancies, such as chin deviation or canting. Early correction is crucial, as these changes become increasingly permanent post-growth. This contrasts with the other options: EARR is more tied to orthodontic forces, attrition typically affects the shifted/working side's teeth, and anterior open bite relates to habits or vertical discrepancies rather than lateral shifts.

Malocclusion affecting the production of sibilant sounds

 # The production of sibilant sounds (e.g., 's', 'z') is most commonly affected by which two concurrent malocclusion features due to uncontrolled air escape and altered tongue positioning?

A. Unilateral Posterior Crossbite and Midline Discrepancy

B. Severe Mandibular Crowding and Deep Overbite

C. Excessive Overjet and Anterior Open Bite

D. Class III Malocclusion and Edge-to-Edge Incisors

The correct answer is: C. Excessive Overjet and Anterior Open Bite

Sibilant sounds like 's' and 'z' rely on precise airflow through a narrow tongue-to-palate groove, and disruptions from excessive overjet (protruding upper incisors) alter tongue positioning, while anterior open bite allows uncontrolled air escape through the anterior gap, often causing lisps or distortions. Studies confirm this combination's strong impact on sibilants, unlike the other options, which less directly affect anterior airflow or tongue placement for these sounds.

Severe, localized pathologic attrition on the palatal surfaces of maxillary incisors and the incisal edges of mandibular incisors is most commonly pathognomonic of which specific malocclusion?

 # Severe, localized pathologic attrition on the palatal surfaces of maxillary incisors and the incisal edges of mandibular incisors is most commonly pathognomonic of which specific malocclusion?

A. Severe Anterior Open Bite

B. Class II Division 2 Malocclusion (Deep Bite)

C. Unilateral Posterior Crossbite with functional shift

D. Class I Malocclusion with severe posterior crowding

The correct answer is: B. Class II Division 2 Malocclusion (Deep Bite)

This wear pattern—severe, localized pathologic attrition on the palatal surfaces of the maxillary incisors and the incisal edges of the mandibular incisors—is pathognomonic for Class II Division 2 malocclusion, which features retroclined maxillary central incisors and a deep overbite. In this condition, the mandibular incisors contact the lingual (palatal) aspects of the maxillary incisors during occlusion, leading to friction and progressive enamel loss at these sites over time. This contrasts with the other options: anterior open bite reduces incisal contact, unilateral posterior crossbite primarily affects lateral segments, and Class I with posterior crowding does not typically produce this anterior-specific lingual wear.