Keen’s approach is used to elevate zygomatic arch:

 # Keen’s approach is used to elevate zygomatic arch:

A. Extraorally

B. Intraorally

C. Transbuccally

D. Percutaneous route

The correct answer is B. Intraorally

Keen’s approach is a closed reduction technique for isolated zygomatic arch fractures, performed via an intraoral incision in the maxillary buccal vestibule (upper gingival sulcus), allowing indirect elevation with a Rowe's disimpaction forceps or similar instrument inserted through the incision to access and lift the depressed arch. This method minimizes visible scarring, avoids facial nerve risk, and prevents external incisions, though it requires careful closure to avoid complications like oroantral fistula. It contrasts with extraoral approaches (e.g., Gillies temporal), percutaneous stab incisions (e.g., for screws), or transbuccal punctures.

Growth of maxilla in the vertical direction is due to:

 # Growth of maxilla in the vertical direction is due to:

A. Growth of alveolus

B. Growth of sutures

C. Growth of cranial base

D. Growth of synchondrosis

The correct answer is B. Growth of sutures

Vertical growth of the maxilla occurs primarily through inferior displacement facilitated by bone apposition and remodeling at the circum-maxillary sutures (e.g., fronto-maxillary, zygomatico-maxillary, and spheno-maxillary sutures), allowing the maxilla to elongate downward while adapting to surrounding structures like the expanding nasal septum and orbital contents. This mechanism accounts for the majority of vertical maxillary development from infancy through adolescence, with contributions from alveolar apposition around erupting teeth but not as the primary driver. Cranial base growth (via synchondroses) contributes indirectly by providing anteroposterior expansion that influences displacement, but sutural growth is the direct enabler of vertical changes, as supported by classic orthodontic principles (e.g., Enlow's remodeling concepts and Björk's implant studies showing downward vector at ~51° to the cranial base).

Additional parameter in five characteristics of Ackerman-Proffit Classification?

 # Which is added as an additional parameter in five characteristics of Ackerman-Proffit Classification?

A. Curve of Spee

B. Esthetic line of occlusion

C. Smile arc

D. Smile line

The correct answer is B. Esthetic line of occlusion

The Ackerman-Proffit classification evaluates malocclusion using Angle's anteroposterior relationships plus five key characteristics—alignment (perimeter/crowding), transverse relationship (arch width discrepancies), vertical relationship (open/deep bite), overjet (incisor protrusion), and midline deviation (asymmetry)—often visualized via a Venn diagram for comprehensive diagnosis. To enhance esthetic analysis, the esthetic line of occlusion is incorporated as an additional parameter, assessing the curved alignment of the maxillary incisor edges relative to the lower lip during smiling or repose, which helps predict treatment outcomes for facial harmony beyond functional aspects. This addition addresses limitations in purely skeletal classifications by integrating soft-tissue esthetics. Options A (Curve of Spee) relates to occlusal curvature but isn't added here; C (Smile arc) and D (Smile line) are related esthetic features but not specifically the parameter in this system.

Gene therapy targeting the germ-line is:

 # Gene therapy targeting the germ-line is:

A. Heritable

B. Non heritable

C. Sometimes heritable

D. Unrelated to heritability

The correct answer is: A. Heritable

Germ-line gene therapy involves modifying DNA in germ cells (sperm, ova, or their precursors), which integrate into the genome and are transmitted to future generations, making the genetic changes heritable. This contrasts with somatic gene therapy, which targets non-reproductive cells and is non-heritable (option B). Option C is incorrect as heritability is inherent to germ-line targeting, and option D is irrelevant since heritability is the defining feature. Ethical and regulatory concerns limit germ-line therapy in humans, but the biological principle remains clear.