Which one of the following drug does not cause gingival hyperplasia?

 # Which one of the following drug does not cause gingival hyperplasia?

A. Cyclosporine

B. Phenytoin

C. Phenobarbital

D. Nifedipine

The correct answer is: C. Phenobarbital

Explanation:

Gingival hyperplasia is a common side effect of certain drugs due to their impact on fibroblast activity and collagen metabolism.

• Cyclosporine: An immunosuppressant commonly associated with gingival hyperplasia.
• Phenytoin: An antiepileptic drug that frequently causes gingival overgrowth.
• Nifedipine: A calcium channel blocker linked to gingival hyperplasia, especially in patients with poor oral hygiene.
• Phenobarbital: An antiepileptic and sedative-hypnotic drug that does not typically cause gingival hyperplasia.

Which lesion is easy to detect radiographically?

 # Which lesion is easy to detect radiographically?

A. An incipient lesion 

B. One that crosses the dentinoenamel junction (DEJ) 

C. One confined to enamel 

D. One with enamel demineralization 

The correct answer is: B. One that crosses the dentinoenamel junction (DEJ)

Explanation:

Lesions that cross the DEJ are easier to detect radiographically because:

1. Density Difference: When the lesion progresses beyond the DEJ, the change in tissue density between enamel and dentin becomes more pronounced, making it visible on radiographs.
2. Dentin Involvement: Dentin is less mineralized than enamel, so demineralization in this layer appears more distinctly on radiographs.

Other options:

• A. An incipient lesion: These are confined to the outer enamel and are challenging to detect radiographically due to minimal density changes.
• C. One confined to enamel: These may be faint or undetectable on radiographs, especially if demineralization is minor.
• D. One with enamel demineralization: Early enamel demineralization is often too subtle for reliable radiographic detection.

 

Malignant hyperthermia is caused by:

 # Malignant hyperthermia is caused by:

A. Suxamethonium

B. Thiopentone

C. Propofol

D. Cis-atracurium

The correct answer is A. Suxamethonium.

Malignant hyperthermia (MH) is a rare but life-threatening condition triggered in susceptible individuals by certain anesthetic agents. Suxamethonium (succinylcholine), a depolarizing neuromuscular blocker, and volatile anesthetic agents (e.g., halothane, sevoflurane) are common triggers. MH is caused by a genetic mutation in the ryanodine receptor (RYR1) or calcium channel, leading to uncontrolled calcium release in skeletal muscle, resulting in hypermetabolism, muscle rigidity, hyperthermia, and rhabdomyolysis.

The other options are not known to cause malignant hyperthermia:

• Thiopentone: A barbiturate used for induction of anesthesia, not a trigger for MH.
• Propofol: An intravenous anesthetic, considered safe in MH-susceptible individuals.
• Cis-atracurium: A non-depolarizing neuromuscular blocker, not associated with MH.

Sodium hypochlorite irrigation depends upon:

 # Sodium hypochlorite irrigation depends upon:

1. pH

2. Temperature

3. Volume

4. Concentration

A. 1 and 2

B. 2 and 3

C. 1 and 3

D. 2 and 4

The correct answer is: D. 2 and 4 (Temperature and Concentration)

Explanation:

The effectiveness of sodium hypochlorite (NaOCl) irrigation in endodontics depends significantly on:

1. Temperature: Increasing the temperature of sodium hypochlorite enhances its tissue-dissolving ability and antibacterial efficacy.

2. Concentration: Higher concentrations of sodium hypochlorite are more effective in tissue dissolution and microbial elimination. However, they can also increase the risk of cytotoxicity and irritation.

While pH and volume affect sodium hypochlorite's properties, they are not the primary factors affecting its irrigation efficacy.