Bacteriostatic and Bactericidal at high doses

# Some antibiotics are bacteriostatic in nature but bactericidal in high doses, such as:
a- erythromycin
b- amoxycillin
c- tetracycline
d- metronidazole
e- cephalosporin

The correct answer is A. Erythromycin.

Witch Chin is seen due to:

# “Witch Chin” is a postoperative complication that occurs when a mucoperiosteal flap is raised in the symphyseal area because of:
A.  injury to the orbicularis oris
B.  detachment of mentalis muscle
C.  incisive nerve damage
D.  periosteal striping
E.  detachment of the platysma muscle

The correct answer is B. Detachment of mentalis muscle.

Blue black pigmentation of gingiva

# Blue black pigmentation of gingiva is seen with pre existing toxicity of:
A. Bismuth
B. Lead
C. Arsenic
D. Mercury

The correct answer is A. Bismuth

Bismuth pigmentation in the oral cavity usually appears as a narrow, bluish black 
discoloration of the gingival margin in areas of preexisting gingival inflammation.

Periodontal pocket

# A periodontal pocket of 8mm deep having the junctional epithelium coronal to the CEJ is:
A. An infrabony pocket
B. A pseudopocket
C. A true periodontal pocket
D. A furcation involvement

The correct answer is B. A pseudopocket

- Pseudopocket/ gingival pocket/relative or false pocket is formed by gingival enlargement without destruction of underlying periodontal tissues

- True/absolute /periodontal pocket is formed by destruction of supporting periodontal tissues and attachment loss.
- Suprabony/supracrestal/Supraalveolar pocket is formed when bottom of pocket is coronal to underlying alveolar bone

- Infrabony/intrabony/subcrestal /intra-alveolar is formed where bottom of pocket is apical to level to adjacent alveolar bone.

MCQs on Nerve Supply of Head and Neck

# All of the following are true of upper eyelid except:
A. Muscles which close the eyelid are supplied by the facial nerve
B. Muscles which open the eyelid are supplied by the branch of trigeminal nerve
C. Sensory supply is by the fifth cranial nerve
D. Blood supply is by the lacrimal and ophthalmic arteries

# Ptosis may occur due to damage to:
A. Trochlear nerve
B. Occulomotor
C. Trigeminal nerve
D. Superior oblique muscle

# Paralysis of upper eyelid is due to paralysis of:
C. V

Xeroderma pigmentosum is characterized by:

# Xeroderma pigmentosum is characterized by:
A. Autosomal dominant inheritance
B. Inability to repair sunlight induced damage to DNA
C. Irregular accumulation of melanin in the basal cell layer
D. Acanthosis of epithelium with elongation of rete pegs

The correct answer is B. Inability to repair sunlight induced damage to DNA

Xeroderma Pigmentosum
- Inherited disorder involving defective DNA repair genes.
- Increased risk for the development of cancers of the skin when exposed to the UV rays.
- UV light causes crosslinking of pyrimidine residues, thus preventing normal DNA replication.
- Such DNA damage is repaired by the nucleotide excision repair (NER) pathway. Several proteins and genes are involved in NER, and an inherited loss of any one can give rise to xeroderma pigmentosum.


Most common form of reversible cell injury is:

# The earliest and most common form of reversible cell injury is:
A. Cloudy swelling
B. Fatty degeneration
C. Hydropic changes
D. Necrosis

The correct answer is A. Cloudy swelling.

- Reversible cellular changes, cellular swelling, or fatty degeneration (cloudy) are the forms of reversible cell injury.

- Necrosis and apoptosis represent irreversible cell injury. 

Most reactive free radical is:

# Out of the various free radical species, the following radical is most reactive:
A. Superoxide (O2-)
B. Hydrogen peroxide (H2O2)
C. Hydroxyl (OH-)
D. Nitric oxide (NO)

The correct answer is C. Hydroxyl Ion (OH-)
Important mechanisms of cell injury are by damage to DNA, proteins, lipid membranes, and circulating lipids (LDL) by peroxidation caused by oxygen-derived free radicals- superoxide anion (O2-), hydroxyl radical (OH-) and hydrogen peroxide (H2O2). Hydroxyl ion is the most reactive.

Koch postulates were modified for periodontitis by:

# Koch postulates were modified for periodontitis by
(A). Socransky
(B). Glickman
(C). Carranza
(D). Orban

The correct answer is: A. Socransky

Why is dental treatment expensive?

You must have gaped when you first time heard your dentist's fee for a single appointment if you live in North America, Europe or Australia. Although, dentistry is much cheaper in South Asia and other parts of the world not mentioned above, dentists make a good income and their earning rises over years as they gain more clinical experience. But, you may be thinking it is not justified that some dentists charge thousands of dollars for the work of an hour or two. Let's see some of the possible causes why dental treatment is so expensive.

A. Dentistry is not only about knowledge
Dentists gain their expertise in dentistry after long years of study, clinical practice and experience which really has no shortcuts. Knowing the thing is not enough, dentists have to visualise and do the procedures in the same ideal way everytime they do something. Precision and manual dexterity is something that develops after years of practice and an inquisitive mind. If  you don't regard your teeth precious and would not bother if they have to be extracted after some slipshod work by a careless dentist, then you can google search for "cheapest dentist in the town", "cheapest dental clinic", "Dental treatment at minimum price" or something similar. But, if you would like to have quality treatment and value your teeth as much as your life, you must seek references from someone who has had a good dental experience and not to choose your dentist solely based upon your financial condition.

B. Dentistry is a one-to-one patient care
The most experienced dentist in the world and the best dentist in the world also can treat only one patient at a time. Dentistry is not only based on medications and counseling, it involves some procedures which take time that nobody can predict accurately. A seemingly easy tooth extraction may take hours following crown fracture and a patient appearing healthy may go into syncope after injecting the local anesthetic. Some weeping canals take more than five or six visits to become asymptomatic and ready for obturation. Even after the dentist becomes very experienced, things take time, healing takes time. It is said that time is the most precious thing in the world which nobody can buy. But, we are selling our time everyday for some price. Some for very low price, some for reasonable prices and some are getting highly paid for their time. And, it is quite understandable that a good dentist must charge higher.

C. A dentist is as good as his instruments and materials
Dental materials have evolved over years and require a lot of research for their improvement. Their advances in the properties of materials and quality of dental treatment they provide gest reflected on the charge the patient has to pay for some procedure. Owning a clinic requires a lot of capital which would have made a lot of profit were it invested elsewhere. We must not neglect the opportunity cost of the capital as well as the dentist working on your mouth.

D. People have got dental problems, quite a lot, and a single dentist cannot solve them all
Imagine that one day all the people in the world with dental caries decided to have their cavity restored. Dental clinics will get overcrowded. Nobody could get quality treatment. Hasty works done result in more dire circumstances in the future. To prevent this, some dentists gradually increase their fees over the years just to that extent that they are not overburdened by the patients. However experienced a dentist may be, he or she cannot examine and treat more than 20 patients in the long run every single day. After few years of clinical practice, dentists develop back pain and may have to retire professionally due to physical difficulties. Keeping all these things in mind, they charge higher to compensate for that loss. 

E. People are ready to pay anything for pain and fear
Dental pain is one of the most severe types of pain. Periodontal and other painless problems in oral cavity are neglected until the carious process reaches the pulp and the patient goes to the dental clinic jumping with pain. They want immediate relief and are ready to pay any price for it. But, they cannot wait for the appointment date. Because pain and fear are the largest industries in the world exploited by the multinational corporations. The cost of dental treatments could be reduced if preventive, rather than curative approach is done towards oral health.

F. Dentistry can always be done better
There are a lot of ways a dentist can improve. However good the dental work may be there is always some room for improvement. As they have reached certain level of confidence in their work and whenever they feel that they could charge higher without hurting the patients' sentiments and mutual benefits, dentists mark - up their charges.

These all could be the reasons some dentists make a lot of money and some struggle to get a job. What are the reasons do you think that some dentists charge higher and make a lot of money? Do comment below.

Bilateral Mandibular Fracture

# Following bilateral mandibular fracture in the canine region, the following muscles will tend to pull the mandible back:
A. Genioglossus and anterior belly of digastric
B. Genioglossus and mylohyoid
C. Genioglossus and thyrohyoid
D. Genioglossus and masseter

The correct answer is A. Genioglossus and anterior belly of digastric

- Symphysis fracture displacement result from action of mylohyoid muscle resulting from imbalance of action of museles attached to genial tubercles on either side.
- Bilateral fracture in canine region when run obliquely forward muscles acting on it are geniohyoid and genioglossus and anterior belly of digastric muscles.
- Lateral pterygoid muscles inserted into medial fossa on anterior aspect of condyle.
- In condylar fracture head is displaced anteriorly and medially

#Recurrent vesicles which are distributed along the sensory nerve trunk

# The Lesion which is erythematous and with recurrent vesicles that are distributed along the sensory nerve trunk is?
(A). Herpes Zoster
(B). Erythema Multiforme
(C). Recurrent Aphthous
(D). Herpes Gingivostomatitis

The correct answer is A. Herpes Zoster.


Herpes Zoster is a recurrent regional infection caused by the Herpes Zoster virus and is characterized by vesicular eruptions over the skin and mucous membrane in a distinctively unilateral pattern.

After producing chickenpox, the V-Z virus remains dormant in the trigeminal ganglion for decades. The virus may become reactivated following stress, trauma, malnutrition and immune suppression, etc.

Clinical Features
The first branch of the trigeminal nerve is most commonly affected and the disease beside affecting the first branch, may also involve the following other branches like:
- Nasociliary nerve-Causing herpetic Keratitis
 Ciliary nerve- Causing Argyll Robertson pupil.
-Facial nerve- Causing Ramsay Hunt syndrome.

- After the prodromal phase of intense pain, the disease produces clusters of vesicles over the skin and oral mucosa; which characteristically develop on one side of the face up to the midline.

- The lesion usually develops and spreads along the distribution of the sensory nerve unilaterally on one side of the face, while the other side of the face remains completely free of symptoms.

- Within the oral cavity the vesicles also develop unilaterally over the buccal mucosa, soft palate and tongue, etc. and cause stinging pain, paresthesia and severe stomatitis.

- In due course of time the fragile vesicular lesions of the skin and the oral mucosa rupture and they leave painful, 'crateriform' ulcers. 

-  Herpes-zoster is histologically characterized by swelling of the infected epithelial cell cytoplasms due to intracellular edema (ballooning degeneration).

Clinical: The disease is nearly always diagnosed on the basis of its very characteristic clinical findings, e.g.
- Unilateral distribution of the lesion. 
- Early severe pain and paresthesia.
- Facial rash accompanying the stomatitis.

Serology: The disease is diagnosed by the detection of virus-specific antibodies in the serum.

Cytologic smear: Cytologic smears prepared from the vesicular fluid reveal inclusion bodies and ballooning degeneration of the infected cell.

Culture: Tissue culture using vesicular contents produces change in the culture cells which could be correlated with the clinical findings found in the primary infection.

Immunofluorescence: HZV specific antibodies are labeled with a fluorescent dye and seen microscopically.

Aniviral drugs such as acyclovir is given along with antibiotics to prevent secondary infections.