17333

Irreversible pulpitis is characterized by sharp, severe pain that continues even after the stimulus (such as cold) has been removed. 

32224

Normal serum calcium and alkaline phosphatase levels are seen in cherubism.

18972

Secondary impression material for edentulous patients with hyper gag reflex is silicon rubber base.

56904

Mean exposure at the skin from intraoral periapical radiographs is 0.03 mR.

15516

A sanitary pontic is the most appropriate design for a flat ridge and ease of cleansing because it has a minimal or no contact with the underlying ridge, allowing for easy cleaning with dental floss or other hygiene aids. This design minimizes plaque accumulation and inflammation, making it suitable for areas where esthetics are not a primary concern, such as posterior regions. 

45606

11713

Oncofoetal antigens are substances that are normally present in the developing fetus but are found in abnormally high quantities in the tissues of certain cancer cells. These antigens are proteins that can be used as markers for the detection of certain types of cancers. The presence of these antigens in cancer cells suggests that the tumor cells have partially reverted to a more primitive, embryonic stage of development.

Explanation for each option:

1. á-Fetoprotein (AFP): This is an oncofoetal antigen. It is a glycoprotein that is produced by the liver cells of the developing fetus. In adults, the production of AFP is usually very low. However, in cases of certain cancers such as hepatocellular carcinoma (primary liver cancer) and some types of testicular cancer, the tumor cells start producing AFP in large amounts. Therefore, high levels of AFP in the blood can be indicative of these cancers.

2. Carcinoembryonic antigen (CEA): CEA is another example of an oncofoetal antigen. It is a glycoprotein that is present in the gastrointestinal tract, pancreas, and sometimes in the respiratory and reproductive systems of a developing fetus. In adults, CEA levels are typically very low. However, in certain types of cancers, such as colorectal cancer, gastric cancer, and some forms of lung, pancreatic, and breast cancer, the tumor cells may start producing large amounts of CEA, which can be detected in the blood and used as a tumor marker for these malignancies.

3. A and B: Both α-fetoprotein and carcinoembryonic antigen are examples of oncofoetal antigens, so this option is correct.

29229

Sialadenoma papilliferum is a rare, benign salivary gland tumor typically occurring in the palate. It presents as an exophytic, papillary lesion and histologically shows a dual epithelial layer (columnar and cuboidal) with connective tissue cores that may contain plasma cells. The other options, such as monomorphic adenoma or simple ductal papilloma, lack these specific histological features.

34621

The massetric notch in the distobuccal corners of the mandibular denture is due to the action of masseter on buccinator.

26058

Anterior crossbite in a 10-year-old child, particularly if functional, can sometimes be a self-correcting anomaly, especially if the underlying cause (e.g., premature contact) is addressed or with natural growth changes. Other conditions like buccoversion of the mandibular first molar, anterior open bite, and flaring of incisors typically require intervention to correct.