Most common variation of tooth in relation to size and mass is common in ______________ teeth.

 # Most common variation of tooth in relation to size and mass is common in ______________ teeth.

A. Mandibular and maxillary premolar

B. Maxillary canine and premolars

C. Mandibular premolar and third molar

D. Maxillary lateral incisor and third molar

The correct answer is D. Maxillary lateral incisor and third molar.

Microdontia most commonly affects maxillary lateral incisors followed by third molars. 

Macrognathia is not a feature of:

 # Macrognathia is not a feature of:

A. Paget’s disease

B. Leontiasis ossea

C. Acromegaly

D. Parry Romberg Syndrome

The correct answer is D. Parry Romberg Syndrome.

Asymmetry of the face is a feature of Rarry-Romberg syndrome. One side of the face shows relative Micrognathia. 

Parry Romberg syndrome: Genetic disorder characterized by atrophic changes of the deeper structures involving one side of the face (e.g., fat, muscle, cartilage & bone) 

Romberg syndrome: Hemifacial atrophy, progressive atrophy of soft tissue of 1/2 inch of face + contralateral Jacksonian epilepsy & trigeminal neuralgia. 

Taurodontism is characterized by:

 # Taurodontism is characterized by:

A. Hypercementosis

B. Elongated wide pulp canals and short roots

C. Obliterated pulp chambers with secondary dentin deposition

D. Rootless teeth with thin shell of enamel

The correct answer is B. Elongated wide pulp canals and short roots.

Taurodontism (Bull Teeth) is due to failure of hertwig's sheath to invaginate at the proper horizontal level. Mostly molars are involved and the body of tooth is enlarged at expense of roots resulting in rectangular teeth. The roots are short and the pulp chambers are extremely large lacking the usual constriction at cervix of tooth. It has been reported that many patients with Klinefelter syndrome exhibit taurodontism but is not constant feauture of this syndrome.

Developmental enamel defects are most commonly seen in:

 # Developmental enamel defects are most commonly seen in:

A. Primary incisors

B. Primary second molar

C. Permanent incisors

D. Permanent first molar

The correct answer is C. Permanent incisors. 

Clinical studies indicate that most cases of enamel hypoplasia involve those teeth that form within the first year of birth, mainly the central and lateral incisors, cuspids, and first molars. 

• Amelogenesis imperfecta: All teeth of both dentitions are affected to some degree. In some cases, the teeth may appear essentially normal. 

• Hypoplasia due to nutritional deficiency and exanthematous fevers: The teeth most frequently involved are central & lateral incisors, cuspids, and first molars. 

• Enamel hypoplasia due to congenital syphilis: Maxillary & mandibular permanent incisors & the first molars are involved. 

• Enamel Hypoplasia due to local infection or trauma: Most commonly one of the permanent maxillary incisors or a maxillary or mandibular premolar is involved.