Oral Drive Theory

# The oral drive theory to explain thumb sucking habit was given by:
a) Benjamin
b) Sears and wise
c) Sigmund Freud
d) Scheldon

The correct answer is B. Sears and Wise.

According to ORAL DRIVE THEORY OF SEARS AND WISE, prolonged suckling lead to thumb sucking.

BENJAMIN'S TH EORY states that thumb sucking arises from the rooting or placing reflex. Rooting reflex is the movement of infant's head and tongue towards an object touching his cheek. The rooting reflex disappears in normal infants around 7-8 months of age.

According to SIGMOND FREUDIAN THEORY, in the oral phase of psychologic development, the mouth is believed to be an oro-erotic zone. The child has the tendency to place fingers or any other object into the oral cavity.

ORAL GRATIFICATION THEORY BY SHELDON states that if a child is not satisfied with sucking during the feeding period it will persist as a symptom of an emotional disturbance by digit sucking.

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Gonial angle at birth

# The gonial angle at birth is?
a) 110°
b) 115°
c) 175°
d) 145°

The correct answer is D. 145 degrees.

 The mandibular or gonial angle during perinatal period ranges from 135° to 150°; however, soon after birth, it decreases to 130° to 140°. In adult mandible, the gonial angle measures between 110° to 120°. Studies have also indicated that the angle value of females is 3-5° greater than that of males.

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Development of Maxilla

# Maxilla develops by:
a) Endochondral bone formation
b) Intra membranous bone formation
c) Cartilage replacement and intra membranous bone formation
d) Mostly cartilage replacement and a little by intra membranous

The correct answer is B. Intra membranous bone formation.

In endochondral type, the bone formation is preceded by formation of cartilaginous model, which is replaced by bone. Eg: Ethmoid bone, Hyoid, Incus, Stapes.

In intramembranous type, the formation of bone is not preceded by formation ot cartilaginous model. Instead bone is laid directly in a fibrous membrane. Eg: Maxilla, nasal bones, parietals, zygoma, vomer, lacrimal, zygomatic.

 Both intramembranous and endochondral ossification is seen in -occipital, temporal, sphenoid bones.

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Father of Modern Orthodontics

# Father of modern orthodontics is:
a) Dewey
b) Angle
c) Andrew
d) Clark 

The correct answer is B. Angle. 

Many inventors have significantly contributed to the fascinating science of orthodontics. The person given the most credit for pioneering modern orthodontics is Dr Edward H Angle, who is rightly honored as the “Father of Modern Orthodontics.” Publication of Angle’s classification system of malocclusion in 1899 marked a turning point in the history of orthodontics, paving way to establishment of the oldest specialty of dentistry.

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