Mean diameter of inferior alveolar nerve is:

 # Mean diameter of inferior alveolar nerve is:

A. 10 mm

B. 4.7 mm

C. 8 mm

D. 1.7 mm

The correct answer is B. 4.7 mm.

The inferior alveolar nerve is a branch of the mandibular nerve (the third division of the trigeminal nerve), responsible for providing sensory innervation to the lower teeth, chin, and lower lip. Its diameter is significant in clinical practices like dental anesthesia, nerve preservation during surgeries, and implant placement.

• The mean diameter of 4.7 mm reflects the nerve's size as it travels through the mandibular canal.

Inferior Alveolar – exits the mental foramen as the mental nerve and continues as the incisive nerve.

● The nerve to mylohyoid is a motor and sensory branch of the inferior alveolar nerve

● The nerve to anterior belly of the digastric muscle is a motor branch of the inferior alveolar nerve

Molar relation in primary dentition is determined by:

 # Molar relation in primary dentition is determined by:

A. Mesiobuccal cusp of maxillary first molar

B. Buccal groove of mandibular first molar

C. Distal surface of maxillary and mandibular second molar

D. Distal surface of maxillary and mandibular first molar

The correct answer is:

C. Distal surface of maxillary and mandibular second molar

Explanation:

In primary dentition, the molar relationship is determined by the alignment of the distal surfaces of the maxillary and mandibular second molars. This is used to describe the primary occlusion as either:

Flush terminal plane: The distal surfaces of the second molars are aligned in a straight plane.

Mesial step: The mandibular second molar’s distal surface is mesial to the maxillary second molar’s distal surface.

Distal step: The mandibular second molar’s distal surface is distal to the maxillary second molar’s distal surface.

These relationships are important because they influence the development of the permanent molar occlusion.

Clinical sign that is always positive in bone fracture is:

 # Clinical sign that is always positive in bone fracture is:

A. Crepitus

B. Tenderness

C. Abnormal mobility

D. All of the above

The correct answer is:

B. Tenderness

Explanation:
Tenderness is always present in fractures, as it reflects localized periosteal irritation and soft tissue damage.

Other signs, such as:

• Crepitus and abnormal mobility, may not be present in minor or incomplete fractures. These are typically seen in displaced or severe fractures but are not universal findings.

Endocrine disorder is the primary cause of:

 # Endocrine disorder is the primary cause of:

A. Acromegaly

B. Albright’s syndrome

C. Paget’s disease

D. Fibrous dysplasia

The correct answer is A. Acromegaly.

Explanation:

Acromegaly is primarily caused by an endocrine disorder, specifically excess growth hormone (GH) secretion, usually due to a pituitary adenoma. This leads to abnormal growth of bones and soft tissues, particularly in adults.

Other options explained:

B. Albright’s syndrome (McCune-Albright Syndrome): A genetic disorder caused by post-zygotic mutations in the GNAS gene, leading to fibrous dysplasia, café-au-lait spots, and endocrine abnormalities. It is not primarily an endocrine disorder but has endocrine manifestations.

C. Paget’s disease: A bone remodeling disorder of unclear etiology, possibly involving genetic and environmental factors, not primarily endocrine.

D. Fibrous dysplasia: A developmental bone disorder caused by activating mutations in the GNAS gene, not related to endocrine dysfunction as a primary cause.