Dentosphere : World of Dentistry

 # The gene aberrant in dentinogenesis imperfecta is: A. Chromosome 4 B. Chromosome 13 C. Chromosome 21 D. Chromosome 24 The correct answer is A. Chromosome 4. Aberration in chromosome 4 (4q21.3) is associated with Dentinogenesis imperfecta. It encodes dentin specific sialophosphoprotein (DSPP) gene. Deficiency of sialoprotein is also suggested as a causative factor for DI. They are generally tulip shaped.  Chromosome number              Disease  1                                               Vanderwoude syndrome 4                                               Dentinogenesis Imperfecta  4                              ...

 # Deficiency of which vitamin causes glossitis, dementia, rough keratotic areas on skin and gastrointestinal symptoms? A. Riboflavin B. Pyridoxine C. Niacin D. Pantothenic acid The correct answer is C. Niacin. Pellagra is a disease caused by a lack of the vitamin niacin (vitamin B3). Symptoms include inflamed skin, diarrhea, dementia, and sores in the mouth. Areas of the skin exposed to either sunlight or friction are typically affected first. Over time affected skin may become darker, stiffen, peel, or bleed. There are two main types of pellagra, primary and secondary. Primary pellagra is due to a diet that does not contain enough niacin and tryptophan. Secondary pellagra is due to a poor ability to use the niacin within the diet. This can occur as a result of alcoholism, long-term diarrhea, carcinoid syndrome, Hartnup disease, and a number of medications such as isoniazid. Diagnosis is typically based on symptoms and may be assisted by urine testing. 

 # FIGLU excretion test is used to estimate deficiency of: A. Vitamin K B. Vitamin B12 C. Vitamin Folic acid D. Niacin The correct answer is C. Vitamin Folic acid. Folic acid is associated with the metabolism of histidine. Formiminoglutamate (FIGLU) formed in histidine metabolism accumulates and is excreted in urine. Histidine load test utilizing the excretion of FIGLU in urine is used to assess folic acid deficiency. 

 # Which of the following vitamins is destroyed by heat? A. Vitamin A B. Vitamin D C. Biotin D. Thiamin The correct answer is C. Biotin. Biotin is present in many foods, including liver, grains, and eggs. It is also synthesized by intestinal bacteria. The conversion to a coenzyme simply requires that it be covalently linked to the appropriate enzymes. Biotin acts as a carrier of "activated carboxyl" groups for three key enzymes that catalyze carboxylation reactions. The enzymes and the pathways they participate in are: Pyruvate carboxylase (gluconeogenesis), acetyl-CoA carboxylase (fatty acid synthesis), and propionyl-CoA carboxylase (branched chain amino acid catabolism). Biotin deficiency is rare. Excessive consumption of raw egg impairs biotin absorption due to the presence of a biotin-binding protein, avidin, in egg whites. Antibiotics that alter the intestinal flora can also lead to biotin deficiency. Symptoms of deficiency include alopecia, skin and bowel inflammation, ...

# All of the cranial nerve have parasympathetic outflow EXCEPT: A. 5th Nerve B. 7th Nerve C. 3rd Nerve D. 9th Nerve # The future TMJ shows development at: A. 12 week B. 10 week C. 18 week D. 16 week # Area that lies immediately lateral to the anterior perforating substance is: A. Orbital gyrus B. Uncus C. Optic chiasma D. Limen insulae   # Which of the following organ is located posterior to pancreas? A. Kidney B. Stomach C. Colon D. Duodenum # Intrinsic factor of Castle is secreted by which of the following cells in Gastric glands? A. Chief cells B. Parietal cells C. Mucus cells D. B cells # A patient was diagnosed with isolated increase in LDL. His father and brother had the same disease with increased cholesterol. The likely diagnosis is: A. LDL receptor mutation B. Familial lipoprotein lipase deficiency type I C. Familial type 3 hyperlipo...

 # During a Le fort I maxillary osteotomy, the tooth most likely to be injured by a low osteotomy line is the: A. Central incisor B. Cuspid C. First bicuspid D. Lateral incisor The correct answer is B. Cuspid. The cuspids, or canine teeth, have the longest roots in both the maxilla and mandible. The average length of a cuspid tooth from the tip of the root to the tip of the crown is 27 mm. It is vital to know the length and position of the dental roots to avoid injuring the apices of the cuspid teeth during Le Fort I osteotomy and placement of internal fixation (interosseous miniplates or microplates and screws). The dentition may also be injured during stabilization of maxillary or mandibular fractures. The bicuspid, central and lateral incisor, and molar teeth all have roots that are shorter than the roots of the cuspid teeth; the average length of a molar tooth from the tip of the root to the tip of the crown, for example, is 24 mm. Consequently, these teeth are much less likely...

 # Bupivacaine is known to cause rapid and resistant cardiac toxicity when administered in high concentrations and volumes. What is the recent advancement to treat its cardiac toxicity? A. Buffered local anesthetics B. Addition of mannitol to local anesthetic solution C. Use of lipid emulsions to reverse the cardiotoxicity of local anesthetics D. Addition of another anesthetic to bupivacaine The correct answer is C. Use of lipid emulsions to reverse the cardiotoxicity of local anesthetics. Cardiovascular collapse from accidental local anesthetic toxicity is rare but the long-acting amide local anesthetics bupivacaine, levobupivacaine, and ropivacaine have differential cardiac toxicity, but all are capable of causing death with accidental overdose. In recent times, the discovery that lipid emulsion may improve the chance of successful resuscitation has led to recommendations that it should be available in every location where regional anesthesia is performed.