Dentosphere : World of Dentistry

 # Pyruvate dehydrogenase complex contains all EXCEPT: A. Biotin B. NAD C. FAD D. Co-A The correct answer is A. Biotin. Pyruvate dehydrogenase complex (PDC) is a complex of three enzymes that converts pyruvate into acetyl-CoA by a process called pyruvate decarboxylation. Acetyl-CoA may then be used in the citric acid cycle to carry out cellular respiration, and this complex links the glycolysis metabolic pathway to the citric acid cycle. Pyruvate decarboxylation is also known as the "pyruvate dehydrogenase reaction" because it also involves the oxidation of pyruvate. The enzymes involved in PDC are Pyruvate dehydrogenase (E1), Dihydrolipoyl transacetylase (E2), and Dihydrolipoyl dehydrogenase (E3). The cofactors involved are:  TPP (thiamine pyrophosphate), magnesium, lipoate, coenzyme A,  FAD and  NAD+.  Reference:  https://en.wikipedia.org/wiki/Pyruvate_dehydrogenase_complex

 # The benign neoplasm of ‘brown fat’ noted in oral/pharyngeal region is: A. Lipoma B. Hibernoma C. Teratoma D. Brown tumor The correct answer is B. Hibernoma.  Hibernomas are uncommon neoplasms of brown adipose tissue. The most frequent sites of occurrence include the thigh, shoulder, and back. Less common myxoid and spindle cell hibernoma variants are likely to be located in the posterior neck and shoulder. Hibernomas are benign lipomatous neoplasms and have no potential for malignant transformation.  Hibernomas contain brown fat, and the name was coined about the presence of brown fat in hibernating animals. First described by Merkel 1906, these tumors are similar to lipomas in clinical behavior but have unique imaging and histopathologic features. Hibernomas generally present in young adults with a mean age of 38. In summary, these tumors are: Composed of brown fat Represent benign neoplasms Generally well-circumscribed masses Generally are small in size Exhibit slow ...

 # SNA angle describes the relationship of the: A. Maxilla to the cranial base B. Mandible to the cranial base C. Maxilla to mandible D. Maxilla to the upper incisors The correct answer is A. Maxilla to the cranial base.  SNA: the angle between the sella/nasion plane and the nasion/A plane (normal value at the end of growth 82 ± 2°). This angle assesses the antero-posterior position of the maxilla relative to the upper cranial structures.

 # Analysis of skull shape and size, supraorbital ridge, extension of zygomatic arch beyond external meatus, measurement of angle of mandible helps in: A. Sex determination B. Racial determination C. Age determination D. Ethnicity determination The correct answer is A. Sex determination. Skull and facial features like mastoid process, supraorbital ridges, size and architecture of skull can help in determining the sex of patient in 94% cases.  Sex differentiation (Sexing) of a specimen: It can be done using methods as below:    Using craniofacial morphology: T he following 6 traits give accurate results 94% times:  - Mastoid process  - Supraorbital ridge \ - Size and architecture of skull  - Extension of the zygomatic arch beyond the external auditory canal  - Nasal aperture and  - Gonial angle (on the mandible) (Including more features increases accuracy by 2%) 

 # Prolonged retention is usually needed in: A. Diastema B. Mild crowding C. Anterior cross bite D. Deep bite The correct answer is A. Diastema. Fixed (bonded) orthodontic retainers are normally used where intra-arch instability is anticipated and prolonged retention is planned. There are three major indications: • Maintenance of lower incisor position during late growth • Diastema maintenance • Maintenance of posterior tooth position in adults Reference: Proffit's Contemporary Orthodontics, 6th Edition.

 # Root shape before and after orthodontic treatment with radiographic evidence was first given by: A. Kaley and Phillip B. Newman and Proffit C. Ketcham AH D. Malmgren and Lavendar The correct answer is C. Ketcham AH. Albert H. Ketcham was born on August 3, 1870, and grew up in Whiting, Vermont. He graduated from the Boston Dental School in 1892, then moved to Colorado due to ill health. Inspired by the challenges of the young profession of orthodontics, he chose to enter the Angle School of Orthodontia in 1902. As a deep thinker with an inquiring mind, Ketcham explored many of the philosophical and mechanical problems, as well as the controversies of the profession of his day. He was one of the first to investigate root resorption, which continues to be a challenge today. He began to question some of Angle’s arbitrary pronouncements, causing Angle to attack him vehemently as a deviationist. He was smart enough to travel his own way from that time on. He worked hard to improve the...

 # Non caseating granuloma with bilateral Hilar lymphadenopathy is a feature of: A. Histoplasmosis B. Sarcoidosis C. Silicosis D. Tannosis The correct answer is B. Sarcoidosis. Sarcoidosis is described as a multisystem granulomatous disease of unknown origin characterized by the formation of uniform, discrete, compact, non-caseating epithelioid granulomas. It is more common in blacks than in whites. Though many investigators have regarded this disease, of unknown etiology, both infective and noninfective agents have been implicated. Currently the infectious etiology is more favored with focus on Mycobacterium and Propionibacterium. It is interesting to note that there was a belief that sarcoidosis is in some way related to tuberculosis. The factors which stood against were inability to culture the bacteria from the pathological tissues and difficulty in identifying them in stained sections. Reference: Shafer's Textbook of Oral Pathology 7th Edition.