MDS PREP
The solution used to bleach non-vital endodontically treated teeth
1) Chloroform
2) Ether
3) Hydrogen peroxide
4) Sodium hypochlorite
Endodontics
Answer: 3
What is the mechanism of action for acid etching of dentin?
1) Formation of a smear layer.
2) Selective dissolution of hydroxyapatite crystals.
3) Dehydration of the dentin matrix.
4) Both A and B.
Acid etching selectively dissolves the hydroxyapatite crystals in dentin, creating microscopic tags and channels for resin infiltration, which enhances the bond between the restorative material and the tooth structure.
The anterior tooth most likely to display two canals is
1) Maxillary central
2) Maxillary lateral
3) Mandibular central
4) Mandibular lateral
Endodontics
Answer: 4
What is the liquefaction temperature of agar hydrocolloid?
1) 37°C - 50°C
2) 60°C - 70°C
3) 70°C - 100°C
4) 50°C - 65°C
Agar hydrocolloid must be heated to a liquefaction temperature between 70°C and 100°C to be suitable for impression taking.
A young adult shows non-fluctuant, tender and red swelling in the marginal gingival lesion. This is most likely
1. Periodontal abscess
2. Periapical abscess
3. Gingival abscess
4. Periapical sinus
Periodontics
Answer: 3
A young adult with non-fluctuant, tender, and red swelling in the marginal gingival lesion is most likely to have a gingival abscess.
Diabetic insipidus is due to the lack of
1 Insulin
2 Angiotensin.
3 Aldosterone.
4 A.D.H.
Physiology
Answer: 4
Diabetic insipidus is due to the lack of 4. A.D.H. (Antidiuretic hormone).
Explanation:
Diabetic insipidus (DI) is a condition characterized by the production of large
volumes of dilute urine due to the lack of the antidiuretic hormone (ADH) or the
body's inability to respond to it. It is different from diabetes mellitus, which
involves problems with insulin and blood sugar regulation.
1. Insulin: Insulin is a hormone produced by the pancreas that plays a critical
role in regulating blood sugar levels. A deficiency or resistance to insulin
leads to diabetes mellitus, not diabetic insipidus. Diabetes mellitus is
characterized by hyperglycemia (high blood sugar) and increased thirst and urine
production due to the inability of the kidneys to reabsorb glucose properly.
2. Angiotensin: Angiotensin is a hormone system that plays a role in the
regulation of blood pressure and fluid balance. It is involved in the
renin-angiotensin-aldosterone system (RAAS). While it is crucial for maintaining
blood pressure, it is not directly related to the pathophysiology of diabetic
insipidus.
3. Aldosterone: Aldosterone is a mineralocorticoid hormone produced by the
adrenal glands. It helps regulate sodium and potassium levels in the body, which
in turn affects fluid and blood volume. While it is essential for electrolyte
and fluid balance, it does not cause diabetic insipidus when lacking.
4. Antidiuretic hormone (ADH): ADH is a hormone produced by the hypothalamus and
stored in the posterior pituitary gland. It acts on the kidneys to increase
water reabsorption, which leads to the production of concentrated urine. In
diabetic insipidus, there is either a deficiency of ADH or the kidneys fail to
respond to it adequately. This results in the kidneys being unable to reabsorb
enough water, leading to the production of large volumes of dilute urine and
increased thirst.
There are two main types of diabetic insipidus: central and nephrogenic. Central
DI occurs when the pituitary gland does not produce enough ADH, while
nephrogenic DI results from the kidneys' inability to respond to ADH. Both types
lead to an imbalance in water regulation and can cause symptoms such as polyuria
(excessive urine production), polydipsia (excessive thirst), and dehydration if
not managed properly.
To treat diabetic insipidus, the underlying cause must be addressed. If it is
central DI, synthetic ADH (desmopressin) is administered to replace the missing
hormone. If it is nephrogenic DI, the treatment focuses on addressing the
kidney's response to ADH and managing symptoms such as maintaining fluid intake
and sometimes medications to reduce urine output.
A bacterial disease with oral manifestations is
1. Herpes Measles
2. Measles
3. Diphtheria
4. Leishmaniasis
Microbiology
Answer: 4
Diphtheria serious bacterial infection that usually affects the mucous
membranes of the nose and throat.
Diphtheria signs and symptoms usually begin 2 to 5 days after a person becomes
infected. Signs and symptoms may include:
A thick, gray membrane covering the throat and tonsils
A sore throat and hoarseness
Swollen glands (enlarged lymph nodes) in the neck
Difficulty breathing or rapid breathing
Nasal discharge
Fever and chills
Tiredness
Skin (cutaneous) diphtheria
A second type of diphtheria can affect the skin, causing pain, redness and
swelling similar to other bacterial skin infections. Ulcers covered by a gray
membrane also may be a sign of skin diphtheria.