Microscopic feature responsible for the clinical appearance of Wickham striae

 # Which of the following microscopic features is responsible for the clinical appearance of Wickham striae?

A. Fibrin deposition

B. Reduced vascularity

C. Acantholysis

D. Hyperkeratosis

E. Intracellular keratinocyte edema

The correct answer is D. Hyperkeratosis.

Several types of lichen planus within the oral cavity have been described. The most common type is the reticular form, which is characterized by numerous interlacing white keratotic lines or striae (so-called Wickham’s striae) that produce an annular or lacy pattern. The buccal mucosa is the site most commonly involved. 

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Legally dental records are the property of:

 # Legally dental records are the property of:

A. The patient

B. The dentist

C. The state

D. None of the above

The correct answer is B. The Dentist.

Dental radiographs should be kept indefinitely. The dental record must include documentation of informed consent and the exposure of radiographs (e.g., the number and type of films, the rationale for exposure and the interpretation). Legally, dental radiographs are the property of the dentist. Patients do,

however, have a right to reasonable access to the dental radiographs, which includes having a copy of the radiographs forwarded to another dentist.

Patients may refuse dental x-rays, however the dentist must decide whether an accurate diagnosis can be provided and whether treatment can provided.

*** No document can be signed by the patient that releases the dentist from liability.

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The biggest advantage of pulp revascularization in endodontics is:

 # The biggest advantage of pulp revascularization in endodontics is:

A. Achieving continued root development

B. No additional material such as TCP or MTA is required

C. No obturation is needed

D. After control of infection, it can be completed in a single visit

The correct answer is A. Achieving continued root development.

Revascularization is a new treatment method for immature (open apex) necrotic permanent teeth. This technique allows the growth of root even when the pulp is necrotic. This helps in strengthening and avoiding damage to the remaining thin and fragile walls of the immature apex. The main aim of this technique is stimulating the residual apical pulp stem cells which are able to survive due to the abundant blood supply in the open apex cases.

Revascularization procedure aids in:

- Stimulation of odontoblasts or undifferentiated mesenchymal cells at the periapex

- Deposition of the calcific material at the apex as well as lateral dentinal walls

- Normal maturation of the entire root

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MTA can be dissolved by adjunct solution of:

 # Set white MTA can be dissolved by adjunct solution of:

A. Carbonic acid

B. Normal saline

C. Sodium hypochlorite

D. Hydrogen peroxide

The correct answer is A. Carbonic acid. 

Carbonic acid can be effectively used as an adjunct to set white MTA even after 21 days.

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Indications for Prenatal Diagnosis by lnvasive Testing

 Principal Indications for Prenatal Diagnosis by lnvasive Testing

- Advanced maternal age (greater than 35 years)

- Previous child with de novo chromosomal aneuploidy

- Presence of structural chromosome abnormality in one of the parents

- Family history of a genetic disorder that may be diagnosed or ruled out by biochemical or DNA analysis

- Family history of an X-linked disorder for which there is no specific prenatal diagnostic test

- Risk of a neural tube defect (first degree relatives of patients with neural tube defects)

- Fetal abnormalities are suspected on Maternal serum screening and ultrasound examination 

Which of the following is not a sporicidal disinfectant?

 # Which of the following is not a sporicidal disinfectant?

A. Glutaraldehyde

B. Formaldehyde

C. Ethylene oxide

D. Benzalkonium chloride

The correct answer is D. Benzalkonium chloride.

Sporicidal agents are: 

E- Ethylene oxide

F- Formaldehyde

G- Glutaraldehyde

H- Halogens 

Benzalkonium chloride is quartenary ammonium antiseptic which is not sporicidal. Only aldehydes, halogens and ethylene oxide are sporicidal disinfectants. 

Formaldehyde is active against the amino group in the protein molecule. In aqueous solutions, it is marked bactericidal, sporicidal and virucidal. It is used to preserve anatomical specimens and for destroying anthrax spores in hair and wool. 10% formalin containing 0.5% sodium tetraborate is used to sterilize clean metal instruments. 

Glutaraldehyde has an action similar to that of formaldehyde. It is especially effective against the tubercle bacilli, fungi and viruses. 

Ethylene oxide is a colorless liquid with a boiling point of 10.7 degree centigrade and highly penetrating at normal temperature and pressure. Therefore, ethylene oxide can be used for sterilization of heat sensitive equipments like heart lung machine, respirators and dental equipment. 

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Which of the following cannot be reliably used for handwashing?

# Which of the following cannot be reliably used for handwashing?

A. Lysol

B. Cresol

C. Isopropyl alcohol

D. Chlorhexidine

The correct answer is A. Lysol.

Lysol is a phenolic compound derived from coal tar and is highly toxic to humans. It is recommended for disinfection of surfaces in hospital. 

These can be reliably used for handwashing: 

- Chlorhexidine

- Alcohols (isopropyl alcohol, ethyl alcohol)

- Iodine

- Cresol

- Chloroxylenol (dettol)

- Hexachlorophane

- Tincture of iodine

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