# Whenever the caries cone in enamel is larger or at least the same size as that in dentin, it is called as:

# Whenever the caries cone in enamel is larger or at least the same size as that in dentin, it is called as:
A. Residual caries
B. Recurrent caries
C. Forward caries
D. Backward caries

Forward Caries. Forward caries is where the caries cone in enamel is larger or at least the same size as that in dentin.

Backward Caries. When the spread of caries along the DEJ exceeds the caries in the contiguous enamel, caries extends into this enamel from the junction.

Ans is C: Forward caries (Ref: Sturdevant's Art and science of operative dentistry 4th ed., p 274)

# DPT vaccine does not provide immunity against:

# DPT vaccine does not provide immunity against:
A. Tetanus
B. Diphtheria
C. Polio
D. Whooping cough

The correct answer is C. Polio.

The vaccine DPT stands for Diphtheria, Pertusis (Whooping cough) and Tetanus. 

# I.V. Diazepam in a patient on a dental chair can cause: [AIIMS 2007 NOV]

# I.V. Diazepam in a patient on a dental chair can cause: [AIIMS 2007 NOV]
A. Tinel’s Sign
B. Verrill’s Sign
C. Bell’s sign
D. Coleman’s sign

The correct answer is B. Verrill's Sign.

Verrill's  sign has 3 Symptoms which indicate  the correct level after  diazepam sedation.

- 50% eyelid ptosis

- Blurring of vision

- Slurring of speech 

Verrill's Sign

# Tinel's Sign: Tinel sign was used earlier as an indicator of the start of the nerve regeneration. It is elicited by percussion over the divided nerve, which result in tingling sensation in part supplied by peripheral section.

# Coleman's sign: Seen in mandibular fractures. Ecchymosis in the lingual sulcus is pathognomic of mandibular fracture.

 # Bell's Sign: Bell's phenomenon (also known as the palpebral oculogyric reflex) is a medical sign that allows observers to notice an upward and outward movement of the eye, when an attempt is made to close the eyes. The upward movement of the eye is present in the majority of the population, and is a defensive mechanism. 

# Local anesthetic with adrenaline if injected intravenously, what will be the result? ( AIIMS 2014, AIPG 2013)

# Local anesthetic with adrenaline if injected intravenously, what will be the result? ( AIIMS 2014, AIPG 2013)
A. Hypertension with Tachycardia
B. Hypotension with Tachycardia
C. Hypotension with Bradycardia
D. Hypertension with Bradycardia

The correct Answer is: A. Hypertension with Tachycardia.

 # In a hypertensive patient on B-blockers, an injection of Local anesthesia + Adrenaline will cause:
A. Hypertension and Tachycardia
B. Hypertension and Bradycardia
C. Hypotension and Tachycardia
D. Hypotension and Bradycardia

The correct answer is B. Hypertension and Bradycardia.

• There are two separate drug interaction considerations with local anesthetics, the anesthetic itself and the vasoconstrictor.

• Hypertensive events have been documented in patients taking B blockers, Furazolidone, Tricyclic antidepressants, methyl dopa, and the antihypertensive drugs guanethidine and Rauwolfia alkaloids.

• Beta blocker interactions are potentially the most serious ones and cause hypertension and bradycardia. 

Why do people have crooked teeth?

Mal-aligned teeth or crooked teeth are problematic not only aesthetically but also from a health point of view. Irregularly placed teeth when present are difficult to clean and maintain hygiene, affect the speech, alters the facial profile and decreases the quality of smile and overall confidence of the person.

Let's see what are the causes of having crooked teeth.

1. Heredity and Evolution
During the course of evolution, the size of man's jaw has been decreasing gradually. Before thousands of years it is believed that human's used to have long jaws and even four molars. Present day human has smaller jaws and even third molars are impacted and need to be removed surgically these days.

Also, heredity also plays an important in proper alignment of teeth. If any of the parents have crooked tooth, the offsprings may also inherit the same.

2. Tooth size arch length discrepancy
When the jaws are smaller and they cannot accommodate all the teeth in the arch properly, the teeth get displaced out of arch due to crowding. Decrease arch length may be due to actual enlargement of tooth, also called Macrodontia, or may be due to retarded growth of maxilla or mandible. Moreover due to consumption of more soft and refined foods, the jaw growth is deficient and the teeth fail to accommodate.

Also the arch length is lost when the deciduous tooth are removed early due to caries or the mesiodistal width of teeth is reduced due to proximal caries. The permanent successor teeth  cannot get enough space to erupt in the arch and become crooked.

3. Habits
Abnormal habits like mouth breathing, tongue thrusting and thumb sucking also exert unnatural forces on the orofacial structures and cause malocclusion.

When diagnosed and treated early, orthodontic treatment can have best outcome and restore natural and healthy smile. Even after the growth phase is completed, crooked teeth can be aligned using fixed archwires and brackets by your Orthodontist. Please visit your nearest Orthodontist if you have got any crooked tooth.

MCQs in Public Health Dentistry - Biostatistics

The correct answers are highlighted in green.

# The arithmetical average of a number of observations is called :
 A. Mean 
 B. Median
 C. Range

 D. All of the above

# Which of the following correlates highest correlation between variables ? 

 A. r= + 0.25 

 B. r= + 0.5 

 C. r= - 0.75 

 D. r= + 2 

Gemination, Twinning, Concrescence and Fusion of Teeth

Gemination:

• An attempt at division of a single tooth before calcification, resulting in incomplete formation of two teeth.

• The resultant structure will have two completely or incompletely separated crowns with a single root and root canal.

• It is difficult to differentiate between gemination and a case in which there has been fusion between a normal tooth and a supernumerary tooth.

Twinning:

The division of a single tooth resulting in one normal and one supernumerary tooth. The number of teeth will be more than normal.

Concrescence:

• A form of fusion of cementum after completion of root formation

• The teeth are united by cementum only.

• Maxillary molars are frequently involved

Fusion: 

• Union of two normally separated tooth germs.

• If the union occurs before calcification, the two teeth are completely united to form a single Large tooth.

• If the union occurs after calcification, there is union of roots only. The tooth may have separate or fused root canals.

•  Fusion of teeth is more common in deciduous teeth.