Marked reduction in the amount of dentin, widening of predentin layer, presence of large areas of interglobular dentin and irregular pattern of dentin

# Which of the following condition shows marked reduction in the amount of dentin, widening of predentin layer, presence of large areas of interglobular dentin and irregular pattern of dentin?

A. Hypocalcified dentin

B. Regional odontodysplasia

C. Dentin dysplasia

D. Dentinogenesis imperfecta

The correct answer is B. Regional odontodysplasia.

The most characteristic features of Regional odontodysplasia are the marked reduction in the amount of dentin, the widening of the predentin layer, the presence of large areas of interglobular dentin, and an irregular tubular pattern of dentin.

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Dentigerous cyst is likely to cause:

# Dentigerous cyst is likely to cause:

A. Ameloblastoma

B. Fibrosarcoma

C. Adenocarcinoma

D. All of the above

The correct answer is A. Ameloblastoma.

Several relatively serious potential complications exist stemming from the dentigerous cyst, besides simply the possibility of recurrence following incomplete surgical removal. These include:

􀁏 The development of an ameloblastoma either from the lining epithelium or from rests of odontogenic epithelium in the wall of the cyst.

􀁏 The development of epidermoid carcinoma from the same two sources of epithelium.

􀁏 The development of a mucoepidermoid carcinoma, basically a malignant salivary gland tumor, from the lining epithelium of the dentigerous cyst which contains mucus secreting cells, or at least cells with this potential, most commonly seen in dentigerous cysts associated with impacted mandibular third molars.

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Cancer which most commonly metastasizes to jaw bone is:

# Cancer which most commonly metastasizes to jaw bone is:

A. Breast

B. Prostatic

C. Lung

D. Kidney

The correct answer is A. Breast

Metastasis to the jaw bones mainly occurs in the posterior region of the mandible, ramus, and the condyle, which are rich in red bone marrow. Metastasis to the maxilla is rare and comprises one-fifth of all metastatic tumors to the jawbones.[1] The male-to-female ratio is almost equal with a ratio of 1:1.1. The mean age of patients is 45 years.[2] The primary focus in women is usually located in the breasts, reproductive organs, thyroid gland, and kidneys, whereas in men it is in the lungs, prostate, kidneys, bones, large intestine, and suprarenal glands.[3,4,5] Metastases to the jaw bones almost originate from infraclavicular regions. The diffusion through Batson's venous system is the principal process of the oral cavity metastasis.[6] Histologically, the primary foci are usually carcinomas, and among them adenocarcinomas are more common. Adenocarcinoma is usually a metastasis from the breasts in women or from the lungs, alimentary canal, or prostate in men. 

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References: 

1. Antunes AA, Antunes AP. Gnathic bone metastasis: A retrospective study of 10 cases. Braz J Otorhinolaryngol. 2008;74:561–5. [PubMed] [Google Scholar]

2.  Singh H, Kumar P, Nirwan A, Kaur R. Possible pathogenetic mechanisms and overview of metastatic tumours to the oral cavity. Internet J Oncol 8 [Google Scholar]

3. Friedrich RE, Abadi M. Distant metastases and malignant cellular neoplasms encountered in the oral and maxillofacial region: Analysis of 92 patients treated at a single institution. Anticancer Res. 2010;30:1843–8. [PubMed] [Google Scholar]

4. Kaugars GE, Svirsky JA. Lung malignancies metastatic to the oral cavity. Oral Surg Oral Med Oral Pathol. 1981;51:179–86. [PubMed] [Google Scholar]

5. Shin SJ, Roh JL, Choi SH, Nam SY, Kim SY, Kim SB, et al. Metastatic carcinomas to the oral cavity and oropharynx. Korean J Pathol. 2012;46:266–71. [PMC free article] [PubMed] [Google Scholar]

6. Batson OV. The function of the vertebral veins and their role in the spread of metastases. 1940. Clin Orthop Relat Res. 1995:4–9. [PubMed] [Google Scholar]

In trauma or surgery which of the following fluids should be avoided?

 # In trauma or surgery which of the following fluids should be avoided?

A. 5% Dextrose

B. Isotonic saline

C. Ringer lactate

D. Blood

The correct answer is B. Isotonic saline.

Hypovolemic shock due to hemorrhage results in cellular anaerobic metabolism and lactic acidosis. This acidosis leads to decreased function of the coagulation proteases, resulting in coagulopathy

and further haemorrhage.  Underperfused muscle is unable to generate heat and hypothermia ensues. Coagulation functions poorly at low temperatures and there is further haemorrhage, further hypoperfusion and worsening acidosis and hypothermia. These three factors result in a downward spiral leading to physiological exhaustion and death. 

Intravenous blood and fluids are cold and exacerbate hypothermia. Further heat is lost by opening body cavities during surgery. Surgery usually leads to further bleeding and many crystalloid

fluids are themselves acidic (e.g. normal saline has a pH of 6.7). 

So, identification and stoppage of hemorrhage should be done immediately and physiological exhaustion from coagulopathy, acidosis and hypothermia should be avoided or limited. 

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Which of the following inhalational anesthetic has analgesic property?

 # Which of the following inhalational anesthetic has analgesic property?

A. Nitrous oxide

B. Halothane

C. Enflurane

D. Sevoflurane

The correct answer is A. Nitrous oxide

The use of nitrous oxide to relieve the pain of surgery was suggested by Humphrey Davy in 1800. He was the first person to make nitrous oxide, and he tested its effects on several people, including himself and the Prime Minister, noting that it caused euphoria, analgesia and loss of consciousness. The use of nitrous oxide, billed as ‘laughing gas’, became a popular fairground entertainment and came to the notice of an American dentist, Horace Wells, who had a tooth extracted under its influence, while he himself squeezed the inhalation bag.

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A diabetic patient in the waiting room develops giddiness, sweating and confusion, he is suffering from:

 # A diabetic patient in the waiting room develops giddiness, sweating and confusion, he is suffering from:

A. Hypertension

B. Ketoacidosis

C. Hypoglycemia

D. Hyperglycemia

The correct answer is C. Hypoglycemia.

Signs and symptoms of low blood sugar (happen quickly)

Feeling shaky.

Being nervous or anxious.

Sweating, chills and clamminess.

Irritability or impatience.

Confusion.

Fast heartbeat.

Feeling lightheaded or dizzy.

Hunger.

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Carcinoma due to chronic irritation is:

 # Carcinoma due to chronic irritation is:

A. Kangri cancer

B.  Countryman’s injury

C. Chimney-sweepers cancer

D. All of the above

The correct answer is D. All of the above.

Kangri cancer is a type of squamous-cell carcinoma of the skin. It is found only in Kashmir in the northwest of the Indian subcontinent. It occurs on the lower abdomen and inner thighs and is due to the use of a kanger, a ceramic pot covered with wicker-work, carried as a source of warmth during cold weather. 

Actinic cheilitis is cheilitis (lip inflammation) caused by long term sunlight exposure. Essentially it is a burn, and a variant of actinic keratosis which occurs on the lip. It is a premalignant condition, as it can develop into squamous cell carcinoma (a type of mouth cancer). This is also known as sailor's lip or farmer's lip or countryman's lip.

Chimney sweep's cancer, also called soot wart, is a squamous cell carcinoma of the skin of the scrotum. It has the distinction of being the first reported form of occupational cancer, and was initially identified by Percivall Pott in 1775. It was initially noticed as being prevalent amongst chimney sweeps.

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