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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Pseudoepitheliomatous hyperplasia

# Which among the following shows pseudoepitheliomatous hyperplasia?
a) Squamous cell carcinoma
b) Basal cell carcinoma
c) Verrucous carcinoma
d) Granular cell myoblastoma

The correct answer is D. Granular cell myoblastoma.

Granular cell myoblastoma is a benign tumor of muscle tissue origin, most commonly involving tongue. The epithelium exhibits pseudoepitheliomatous hyperplasia because of which it is confused with epidermoid carcinoma.

NOTE:
Pseudoepitheliomatous hyperplasia is also seen in:
• Granular cell myoblastoma
• Blastomycosis
• Papillary hyperplasia
• DLE (Discoid lupus erythematosus)


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High rate of Cancer

# Increased incidence of carcinoma is observed with:
a) Homogenous leukoplakia
b) Verrucous leukoplakia
c) Nodular leukoplakia
d) None of the above

The correct answer is C. Nodular Leukoplakia.

Clinically, Leukoplakia is of three types:
A. Homogenous
B. Speckled or Nodular
C. Proliferative verrucous leukoplakia (PVL)

A. Homogenous
• Appears as translucent white, raised area. • It is non-palpable i.e., same as surrounding mucous membrane.
• Differential diagnosis is hyperplastic lichen planus.

B. Speckled or Nodular 
• Raised from surface with red and white areas.
• Mostly seen at the angle of mouth and commissures of lips in chronic smokers.
• Indurations, fissuring and ulcer formation is seen
• The epithelial dysplasia is more common and has more tendency for malignancy.

C. Proliferative verrucous leukoplakia (PVL) 
• First described by Hansen and is associated with a high risk of progression to squamous cell carcinoma.
• May be associated with human papilloma virus (HPV)
• Seen as white papilliferous or cauliflower like growth
• Commonly seen in the region, where the quid is kept for long time
• No fixity is seen
• Differential diagnosis is verrucous carcinoma.


Note:
The forms of leukoplakia according to CURRENT classifications are:
1) Homogeneous: 
Lesions that are uniformly white.
a) Smooth
b) Furrowed (Fissured)
c) Ulcerated

2) Nonhomogeneous nodulospeckled: Lesion with well demarcated raised white areas, interspersed with reddened areas. It is applicable to both color (mixed red and white lesion -erythroleukoplakia) and texture (exophytic, papillary or verrucous).

Proliferative verrucous leukoplakia is a term used to describe a clinically aggressive form or oral leukoplakia with a strong potential for malignant transformation.


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Elephantiasis neuromatosa

# Elephantiasis neuromatosa is a feature of:
a) Von Recklinghausen's disease
b) Neurilemmoma
c) Paraganglioma
d) Multiple endocrine neoplasia syndrome

The correct answer is A. Von Recklinghausen's disease.

Two distinct variants of Elephant man syndrome or von Recklinghausen's neurofibromatosis are known. Type 1 which is often associated with oral lesions and neurofibromatosis 2 (bilateral acoustic neurofibromatosis) is less common and is less frequently associated with obvious peripheral neurofibromatosis or oral lesions.

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Flush Terminal Plane

# If a flush terminal plane is present in the deciduous dentition then the molars will erupt:
a) Initially in class I occlusion
b) Initially in class II occlusion
c) Initially in class III occlusion
d) End to end

The correct answer is D. End to End

Baume's classification of primary molars

Flush terminal plane : 
• The distal surface of upper and lower second deciduous molars are in one vertical plane.
• The permanent molars will erupt in a flush or end on relationship.

Mesial Step:
• The distal surface of lower second deciduous molar is more mesial to that of upper second deciduous molar.
• Mesial step- (normal mesial step of < 2mm, which is more common)- The permanent molars will erupt in Angle's class-I occlusion
• Exaggerated Mesial step of >2 mm- The permanent molars will erupt in Angle's classIII occlusion

Distal Step:
• The distal surface of lower second deciduous molar is distal to that of upper second deciduous molar.
• The permanent molars may erupt in Angle's class-II occlusion.

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