Cyst without a lining is :

 # Cyst without a lining is : 

a Radicular cyst 

b. Nasopalatine duct cyst 

c. Dentigerous cyst 

d. Hemorrhagic/traumatic bone cyst 

The correct answer is D. Hemorrhagic/Traumatic bone cyst.

The traumatic cyst is a pseudo cyst (lacks an epithelial lining) and an uncommon lesion comprises about 1% of all jaw cysts. It occurs in other bones of the skeleton as well.

Etiology. The etiology of the solitary bone cyst is unknown, although a number of theories have been proposed and at least one, the trauma—hemorrhage theory has been rather widely accepted. Howe and also Sieverink have carried out extensive reviews of the literature and pointed out the wide acceptance

of the theory of origin from intramedullary hemorrhage following traumatic injury. Hemorrhage occurring within the medullary spaces of bone after trauma heals in most cases by organization of the clot and eventual formation of connective tissue and new bone. According to the traumatic theory, the

clot breaks down and leaves an empty cavity within the bone. Steady expansion of the lesion occurs secondary to altered or obstructed lymphatic or venous drainage. This expansion tends to cease when the cyst-like lesion reaches the cortical layer of bone, so that expansion of the involved bone is not a common finding in the solitary bone cyst.

Giant cell fibroma occurs commonly on:

 # Giant cell fibroma occurs commonly on:

A. Maxillary gingiva

B. Mandibular gingiva

C. Tongue

D. Palate

The correct answer is B. Mandibular gingiva.

Most common benign soft tissue neoplasm is fibroma (oral fibroma or fibromatosis fibroma) and its most common site is buccal mucosa. Giant cell fibroma is a distinctive entity from a conventional fibroma. The most common site is the mandibular gingiva, followed by the maxillary gingiva, the tongue, and the palate 

Syndrome in which all patients look similar, without being genetically linked to each other is:

 # Syndrome in which all patients look similar, without being genetically linked to each other is:

A. Hereditary ectodermal dysplasia

B. Von Recklinghausen

C. Gardner syndrome

D. Rosenthal syndrome

The correct answer is A. Hereditary ectodermal dysplasia. 

Hereditary ectodermal dysplasia is a large, heterogeneous group of inherited disorders involving skin, hair, nails, eccrine glands, and teeth. It is characterized by hypohidrosis, hypodontia, onychodysplasia, and hypotrichosis. Typical facies are characterized by frontal bossing, sunken cheeks, saddle nose, thick, everted lips, wrinkled hyperpigmented skin around the eyes, and low-set ears. Other common signs are short stature, eye abnormalities, decreased flow of tears, and photophobia. Since most of the signs are common, they resemble each other. 

BDS THIRD PROFESSIONAL EXAMINATION - GENERAL MEDICINE MODEL QUESTIONS

1. A fifty-year-old man presents in the emergency ward with central chest pain. On examination, his blood pressure is 90/60 mmHg and his pulse is 106 per minute. He is pale and sweating profusely. The most likely diagnosis is: 

a) Esophagitis. 

b) Myocardial infarction. 

c) Pericarditis. 

d) Pleural effusion. 

e) Pneumothorax. 

Key: b 

Ref: Myocardial Infarction (591) Davidson's Principles and Practice of Medicine. 

2. A thirty-five-year-old man presents in a clinic with history of chronic productive cough that is worse in the morning and brought on by changes in posture. Sputum is copious and yellow. The most likely diagnosis in this patient is: 

a) Bronchial asthma. 

b) Bronchiectasis. 

c) Bronchogenic carcinoma. 

d) Chronic bronchitis. 

e) Pulmonary tuberculosis. 

Key: b 

Ref: Bronchiectasis (Page 684) Davidson's Principles and Practice of Medicine. 

3. A twenty-year-old girl is taking anti-tuberculosis treatment. She presents in eye outdoor with visual complaints. The most likely cause of her symptoms is side effect of: 

a) Isoniazid. 

b) Rifampicin. 

c) Ethambutol. 

d) Pyrazinamide. 

e) Streptomycin. 

Key: c 

Ref: Adverse Reaction of First Line Anti Tuberculosis Drugs (Page 702) Davidson's Principles and Practice of Medicine. 

For extraoral maxillary nerve block, the target area is:

 # For extraoral maxillary nerve block, the target area is:

A. Anterior to lateral pterygoid plate

B. Posterior to lateral pterygoid plate

C. Pterygomandibular fossa

D. Pterygomandibular fissure

The correct answer is A. Anterior to the lateral pterygoid plate. 

In the extraoral technique for maxillary nerve block, the needle is directed anteriorly to the lateral pterygoid plate into the pterygopalatine fossa. The midpoint of the zygomatic process is located and depression in its inferior surface is marked. The needle is inserted perpendicular to the median sagittal plane until the needle point gently contacts the lateral pterygoid plate. 

How much reduction in strength and toughness in endodontically treated molars is attributed to changes in collagen cross-linking and dehydration of dentin?

 # How much reduction in strength and toughness in endodontically treated molars is attributed to changes in collagen cross-linking and dehydration of dentin?

A. 5 %

B. 14 %

C. 21 %

D. 60 %

The correct answer is B. 14 %.

There is almost a 14 % reduction in toughness in endodontically treated molars compared with vital dentin due to changes in collagen cross-linking and dehydration of dentin. 

Ref: Cohen 10th Edition , Page 462

Stimulation of trigeminal nerve during gap arthroplasty surgery causes?

 # Stimulation of trigeminal nerve during gap arthroplasty surgery causes?

A. Paroxysmal atrial tachycardia

B. Ventricular tachycardia

C. Bradycardia

D. Torsades de pointes

The correct answer is C. Bradycardia.

Trigeminocardiac Reflex (TCR) 

■ This basically means that stimulation of the trigeminal nerve causes vagally mediated bradycardia, which, in severe cases may even cause asystole. 

■ The trigeminocardiac reflex is the sudden-onset of dysrhythmia and hypotension during manipulation of any of the branches of the trigeminal nerve. The trigeminal nerve and cardioinhibitory vagus nerve constitute the afferent and efferent pathway in the reflex arc. 

■ In pediatric patients, the sympathetic nervous system is not fully developed, giving the parasympathetic nervous system greater control and increased tone. A severe and sudden bradycardia can often be the result of this parasympathetic hypertonia or "increased vagal tone " 

■ It is important to note that the incidence is inversely proportional to age with a sharp decline in incidence for children over the age of 3. 

■ Oculocardiac reflex (Aschner phenomenon) is a type of TCR due to stimulation of the ocular division of the trigeminal nerve.