Dentosphere : World of Dentistry

 # 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 mo...

 # A potential iatrogenic adverse consequence of treating maxillary incisor proclination with retraction mechanics is a decrease in the: A. Depth of the nasolabial angle due to soft tissue retraction B. Vertical height of the alveolar process in the anterior mandible C. Maxillary incisor root proximity to the nasal floor and palatal cortex D. Posterior arch width due to transverse forces The correct answer is C. Maxillary incisor root proximity to the nasal floor and palatal cortex When maxillary incisors are retracted (moved backward) to correct proclination (forward tipping), the entire tooth structure, including the root, moves posteriorly. The root apices of the maxillary incisors are naturally close to the nasal floor superiorly and the palatal cortical plate posteriorly. Significant retraction, especially with bodily movement or lingual tipping, can push the root apices closer to these anatomical boundaries. This decreased proximity (i.e., the distance becomes smaller) incre...

 # The primary benefit of early (Phase I) correction of a mandibular functional shift is to: A. Improve the patient’s TMJ range of motion in maximal opening B. Prevent asymmetric growth and irreversible skeletal asymmetry of the mandible C. Reduce the risk of buccal non carious cervical lesions D. Avoid extraction of premolar teeth in the permanent dentition The correct answer is B. Prevent asymmetric growth and irreversible skeletal asymmetry of the mandible Mandibular functional shifts, typically from unilateral posterior crossbite, cause the mandible to deviate laterally (1–3 mm) into centric occlusion to bypass interferences, altering condylar positioning and asymmetric loading during growth—leading to differential mandibular ramus/fossa remodeling (e.g., 1–2 mm longer body on shifted side) and progressive skeletal asymmetry (chin deviation, facial canting) that becomes increasingly fixed post-puberty. Phase I correction (e.g., rapid maxillary expansion in mixed dentition) eli...

 # An uncorrected anterior open bite with a tongue thrust habit can lead to an adverse consequence in the dental alveolar complex via a mechanism of: A. Disruption of the equilibrium between tongue and lip muscle forces B. Increased risk of periodontal bone loss due to heavy occlusal forces C. Pathologic attrition of the posterior teeth D. Skeletal mandibular retrusion The correct answer is A. Disruption of the equilibrium between tongue and lip muscle forces In uncorrected anterior open bite with tongue thrust, the aberrant lingual pressure during deglutition and speech exerts a supracrestal force (20–50 N) on the lingual inclines of maxillary and mandibular incisors, overriding the restraining orbicularis oris and mentalis tonicity—resulting in progressive labial flaring, anterior spacing, and failure of spontaneous closure, with alveolar bone remodeling adapting to this disequilibrium (e.g., reduced interradicular bone density via osteoclast activation). This perioral imbalance ...

 # The primary goal of pre-orthodontic or phase I alignment of severely crowded incisors that are planned for permanent extraction (e.g. premolar) is to: A. Reduce the risk of post treatment gingival recession B. Decrease the overall duration of the comprehensive treatment C. Prevent external apical root resorption of adjacent teeth D. Align the roots parallel for optimal force distribution during space closure The correct answer is D. Align the roots parallel for optimal force distribution during space closure In extraction cases with severe incisor crowding, initial (phase I) alignment using light round NiTi wires uprights and derotates the anterior teeth, paralleling their roots to position the center of resistance (CR) along the retraction force vector—enabling bodily translation rather than uncontrolled tipping during subsequent en masse space closure (e.g., via chain or coil springs). This optimizes biomechanical efficiency, reduces unwanted extrusion or lingual crown tipping...

 # The benefit of orthodontic correction for a single tooth with infraocclusion is primarily to: A. Improve the patient's vertical dimension of occlusion (VDO) B. Eliminate the need for prosthetic replacement of the tooth C. Reduce the risk of periodontal bone loss on the adjacent teeth D. Prevent future TMJ derangement and pain The correct answer is C. Reduce the risk of periodontal bone loss on the adjacent teeth. Uncorrected infraocclusion (often from ankylosis) causes compensatory tipping and overeruption of adjacent teeth (e.g., first permanent molar mesially tilting into the space), leading to eccentric occlusal loading, plaque stagnation in tilted contacts, and progressive alveolar bone resorption on those neighbors—up to 1–2 mm loss over 1–2 years if severe. Orthodontic intervention restores occlusal plane integrity, preventing this cascade: studies show it minimizes adjacent tipping by 70–90%, preserving arch length, symmetry, and periodontal health (e.g., stable probing d...

 # Which adverse consequence of malocclusion has the highest correlation with a patient's socio-economic status and access to dental care, rather than the malocclusion's severity alone? A. Functional lateral mandibular shift B. Increased risk of incisor trauma C. Pathologic attrition leading to dentin exposure D. Early and severe development of dental caries The correct answer is D. Early and severe development of dental caries Crowding and irregular alignment in malocclusion create plaque-retentive areas that hinder effective oral hygiene, elevating caries risk by 1.5–2.5 times, but this consequence is disproportionately amplified in lower socioeconomic status (SES) populations due to confounding factors like high-sugar diets, limited fluoride exposure, infrequent professional cleanings, and poor access to preventive care—resulting in DMFT scores 20–50% higher in low-SES groups regardless of malocclusion severity alone. Cross-sectional studies in vulnerable cohorts (e.g., refu...