Dentosphere : World of Dentistry

# All of these are principal fibers of Periodontal ligament except: A. Dentoalveolar crest fibers B. Apical fibers C. Horizontal fibers D. Transseptal fibers The correct answer is:  D. Transseptal fibers Principal Fibers of Periodontal Ligament are: - Alveolar crest, - horizontal , - oblique , - apical , and - interradicular fiber bundles

# Pharynx extends up to which cervical vertebra? [Nepal Medical Council, Dec 2019] A. C3 B. C4 C. C5 D. C6 The correct answer is D. C6 Pharynx The word throat is used for the parts of the neck anterior to the vertebral column, especially the pharynx and the larynx. The pharynx is the part of the digestive system situated posterior to the nasal and oral cavities and posterior to the larynx. It is therefore divisible into nasal, oral, and laryngeal parts: the (1) nasopharynx, (2) oropharynx, and (3) laryngopharynx. The pharynx extends from the base of the skull down to the inferior border of the cricoid cartilage (around the C6 vertebral level) , where it becomes continuous with the esophagus. Its superior aspect is related to the sphenoid and occipital bones and the posterior aspect to the prevertebral fascia and muscles as well as the upper six cervical vertebrae. The pharynx is a fibromuscular tube lined by mucous membrane.

# Pharynx extends up to which cervical vertebra? [Nepal Medical Council, Dec 2019] A. C3 B. C4 C. C5 D. C6 CLICK HERE FOR CORRECT ANSWER WITH EXPLANATION

COLLEGE OF MEDICAL SCIENCES. TEACHING HOSPITAL BHARATPUR            Dec-Jan 2019-2020 Level: IV BDS                                                                                                                            Exam: Send up Subject: Orthodontics                                                                                                              Time: 2 h...

COLLEGE OF MEDICAL SCIENCES. TEACHING HOSPITAL BHARATPUR            Dec-Jan 2019-2020 Level: IV BDS                                                                                                                            Exam: Send up Subject: Periodontics                                                                                                              Time: 2 h...

COLLEGE OF MEDICAL SCIENCES. TEACHING HOSPITAL BHARATPUR            Dec-Jan 2019-2020 Level: IV BDS                                                                                                                            Exam: Send up Subject: Pedodontics                                                                                                              Time: 2 hr...

COLLEGE OF MEDICAL SCIENCES. TEACHING HOSPITAL BHARATPUR           Dec-Jan 2019-2020 Level: IV BDS                                                                                                                            Exam: Send up Subject: Oral Medicine                                                                                                               Ti...

# The most common bone cancer is (AlIMS 94, AIPG 99) a) Osteosarcoma b) Metastatic bone cancer c) Multiple myeloma d) Squamous cell carcinoma The correct answer is: B. Metastatic bone cancer. Metastatic cancers are most common cancers in bone. Multiple myeloma is the common primary bone tumor, whereas the common inherent bone cell tumor is osteogenic sarcoma or osteosarcoma.

# Bifid ribs, multiple radiolucent lesions of the jaws, multiple basal cell nevi and falx ceribri calcification are found in (Man 98, 97) a) Basal cell nevus syndrome b) Sturge weber syndrome c) Horner syndrome d) Hereditary internal polyposis The correct answer is A. Basal cell nevus syndrome. Basal cell nevus syndrome is also called as Gorlin Goltz syndrome. Horner's syndrome is characterized by miosis, ptosis and anhidrosis over face due to interruption of sudomotor and vasomotor control. Hereditary intestinal polyposis is seen in Peutz-Jeghers syndrome.

# Which of the following tumors is most aggressive? (AIPG 91, AIIMS2004) a) Ameloblastoma b) Odontoma c) Odontogenic myxoma d) Fibrocarcinoma The answer is C. Odontogenic myxoma ODONTOGENIC MYXOMAS Aggressive, intraosseous neoplasms derived from embryonic odontogenic mesenchyme probably arise from the dental papilla or follicular mesenchyme. Nearly all lesions are found in the tooth bearing areas of maxillary and mandibular bone. Mandibular lesions are commonly found in the premolar-molar area. The lesions often produce multilocular radiolucency with a "soap bubble' or "honey comb" appearance in the bone. Thin and extremely delicate septa of bone are often seen to course through the radiolucent area and produce a "spider- web" like or "tennis racket" like appearance.  (Ref: Shafer's Textbook of oral pathology 7h ed., p 299)

# Obesity, genetic profile, and aging all contribute to the development of Type II diabetes. Of the following, which is the most important additive factor for these three conditions in the development of Type II diabetes? A. elevated hepatic ketogenesis B. elevated pancreatic glucagon secretion C. impaired renal clearance of glucose D. muscle resistance to insulin Answer: D - Muscle resistance to insulin is the most important additive factor for these three conditions in the development of Type II diabetes. The progressive loss of skeletal muscle sensitivity to insulin leads to increased rates of visceral cell lipolysis and pancreatic beta-cell compensation.

# # All of cranial nerve have parasympathetic outflow except : A. 5th nerve B. 7th nerve C. 3rd neve D. 9th nerve The correct answer is A. 5th nerve Cranial nerves having parasympathetic now are 3,7,9 and 10. Preganglionic parasympathetic neuron cell bodies are located in certain cranial nerve nuclei of the brain stem and in the grey matter of the second to fourth sacral segments of the spinal cord. Efferent fibres, which are myelinated, emerge from the CNS only in cranial nerves III, VII, IX, and X and in the second to fourth sacral spinal nerves. Preganglionic parasympathetic neurons are cholinergic.  The only cranial nerve which arises on the dorsal aspect   -       Trochlear The cranial nerve with longest intracranial coarse              -        Abducent The cranial nerve with longest coarse                      ...

# ___________most often refer pain to the temporal region, while _________most often refer pain the ear. A. Maxillary second premolars, mandibular molars B. Maxillary molars, mandibular molars C.  Maxillary second premolars, mandibular premolars D. Maxillary molars, mandibular premolars The correct answer is A. Maxillary second premolars, mandibular molars. If careful diagnosis does not reveal the affected tooth, other teeth and related anatomic structures become suspect. Pulpitis in one tooth may cause pain in other areas - the pain is referred. Site of Pain Referral                              Pulp of Tooth Causing Pain Forehead region                                    Maxillary incisors Nasolabial area                      ...

# Which of the following statements is TRUE? (MAN-95) a) The hydrolysis of lactose yields glucose and galactose b) The hydrolysis of maltose yields glucose and fructose c) The hydrolysis of sucrose yields only glucose d) All of the above statements are true The correct answer is A. The hydrolysis of lactose yields glucose and galactose Carbohydrate Products Maltose 2 glucose units Sucrose 1 glucose + 1 fructose Lactose Galactose + glucose Starch Water soluble amylose and a water soluble amylopectin Inulin Polymer of fructose

# Advantage of chromic gut over plain is: A. Delayed resorption B. Increased strength C. Less irritation D. Less tissue reaction The correct answer is A. Delayed resorption. Chromic gut sutures consist of the plain gut that has been treated with chromium trioxide. This results in a delay in the absorption rate. Because retention of sutures beyond a few days is not recommended in endodontic surgery, the use of chromic gut sutures offers no advantage. Also, evidence indicates that plain gut is more biocompatible with oral soft tissues than is the chromic gut. The gut suture material is marketed in sterile packets containing isopropyl alcohol. When removed from the packet, the suture is hard and non-pliable because of its dehydration. Before using gut sutures should be hydrated by placing them into sterile, distilled water for 3 to 5 minutes. After hydration, the gut suture material will be smooth and pliable with manipulative properties similar to silk. ...

# Benzodiazepine antagonist is: A. Flumazenil B. Naloxone C. Furazolidone D. Dapsone The correct answer is A. Flumazenil Benzodiazepine act by enhancing presynaptic or postsynaptic inhibition through a specific receptor which is integral part of gabba receptor Cl-channel complex. Flumazenil is a BZD analogue which has little intrinsic activity but it competes with BZDs as well as inverse agonists for BZD receptor and reverses their depressant or stimulant effects respectively. Flumazenil is the drug of choice for benzodiazepine overdose.

# To prevent sensitivity caused by acid etching and to protect pulp in deep cavities, which of the following should be used? A. Calcium hydroxide liner B. ZnO liner C. Light cure GIC liner D. Lining with varnish The correct answer is A. calcium hydroxide liner Deep caries excavation close to the pulp, which may result in either an undetected pulpal exposure or a visible pulpal exposure, should be covered with a calcium hydroxide liner that can stimulate formation of dentin bridges (reparative dentin) over the exposure. For amalgam restorations, deep excavations not encroaching on the pulp should be covered with a glass-ionomer material that will contribute to thermal protection and provide mechanical protection from amalgam condensation forces at thicknesses of I to 1.5 mm or greater.

# Bonding of composite resins to tooth structure is by: (KAR-01) a) Covalent bond b) Ionic bond c) Mechanical d) Vander waal forces The correct answer is C. Mechanical Bonding of composites to tooth structure occurs by micromechanical retention. Acid etching creates micro porosities into which the resin penetrates resulting in resin tag formation. These tags penetrate to a depth of 5 - 10 µm but their lengths are dependent on the enamel etching time.

# The main advantage of composites over unfilled direct filling resin is their: (KAR-97) a) Higher solubility in saliva b) Lower modulus of elasticity c) Esthetic excellence d) Lower thermal co-efficient of expansion The correct answer is D. Lower coefficient of thermal expansion. Advantages of composites over unfilled resins: Lower coefficient of thermal expansion Low polymerization shrinkage Low water absorption High abrasive resistance Disadvantages of composites: Less color stability Less smooth finish than unfilled resins

# The most common reason why hyperplastic tissue is removed during the construction of a complete denture is that: a) It interferes with the arrangement of the teeth b) It is unaesthetic to construct a denture on a hyperplastic tissue c) It interferes with the stability of the denture d) All of the above The correct answer is C. It interferes with the stability of the denture. The most important reason for the treatment of hyperplastic tissue before the construction of complete or removable partial dentures is to provide a firm, stable base for the denture. 

# The amount of functional cusp reduction required for metal-ceramic crown is - a) 1.0 - 2.5 mm b) 1.5 - 2.0 mm c) 2.0 - 2.25 mm d) 1.85 - 2.10 mm The correct answer is B. 1.5 -2.0 mm.  Metal ceramic restorations require a 1.5 - 2 mm reduction in the functional cusp and 1.0 - 1.5mm reduction in the non-functional cusp. 

# Best method to remove gutta-percha in retreatment procedures: A. Hand instrumentation B. Automated instrumentation C. Rotatory instruments D. Ultrasonic instruments The correct answer is A. Hand instrumentation The coronal portion of gutta-percha obturations should always be drilled out, preferably by means of endodontic drills such as the Gates-Glidden or Peeso. Gutta-percha may be dissolved (solvent technique) or removed in its solid form (Solid gutta-percha techniques). Dissolving avoids the use of excessive force in the negotiating of gutta-percha-obturated canals. Extrusion of solvent into the periapical tissues should be prevented. Solvents of gutta-percha: Gutta-percha is soluble in chloroform, ethyl chloroform, carbon disulfide, carbon tetrachloride, benzene, xylene, eucalyptol oil, halothane, and rectified white turpentine. Retreatment of solid objects other than gutta-percha, either a silver point or a fragment of an instrument or post, cannot ...

# Endodontic retreatment: A. Is as technically challenging as original treatment B. Has a poorer prognosis than original treatment C. Is performed only on endodontic failures D. Has different objectives than primary treatment The correct answer is B. has a poorer prognosis than the original treatment

# In restoring an endodontically treated tooth for post core, an absolute minimum of apical fill of gutta percha to be left over to prevent leakage is: A. 1 mm B. 2 mm C. 3 mm D. 4 mm The correct answer is D. 4mm Since there is greater leakage when only 2-3 mm of Gutta-percha is present, 4-5 mm should be retained apically to ensure an adequate seal. Although studies indicate that 4 mm produce an adequate seal, stopping precisely at 4 mm is difficult, and radiographic angulation errors could lead to retention of less than 4 mm. Therefore, 5 mm of gutta-percha should be retained apically. 

# Concentration of EDTA used during biomechanical preparation (BMP) is: A. 20% at pH 7.4 B. 15% at pH 5.0 C. 15% at pH 7.3 D. 25% at pH 7.4 The correct answer is C. 15% at pH 7.3 EDTA has a property of chelate formation with calcium salts. Disodium salt of EDTA is used in endodontic therapy for dissolving pulp stones. 

# Length of a Peeso reamer is: A. 28-32 mm B. 30-35 mm C. 35-40 mm D. 40-45 mm The correct answer is A. 28-32 mm - Standard Peeso reamer is of 32 mm length. - Short Peeso reamer is of 28 mm length.

# Which of the following is called cardiac glycosides? A. Digitalin B. Belladonna C. Reserpine D. Colchicum Cardiac glycosides are a class of organic compounds that increase the output force of the heart and increase its rate of contractions by acting on the cellular sodium-potassium ATPase pump. Their beneficial medical uses are as treatments for congestive heart failure and cardiac arrhythmias; however, their relative toxicity prevents them from being widely used. Cardiac glycosides can be more specifically categorized based on the plant they are derived from, as in the following list. For example, cardenolides have been primarily derived from the foxglove plants Digitalis purpurea and Digitalis lanata, while bufadienolides have been derived from the venom of the cane toad Bufo marinus, from which they receive the “bufo” portion of their name. Cardiac glycosides have long served as the main medical treatment to congestive heart failure and cardiac arrhythm...

# The middle meningeal artery: (MAN -95) a) Enters the skull through the foramen ovale b) Supplies the superolateral surface of the ipsilateral cerebral hemisphere c) Runs a subdural course within the cranial cavity d) Gives an interior branch which runs deep to the pterion The correct answer is D. Gives an interior branch which runs deep to the pterion The middle meningeal artery enters the middle cranial fossa through the foramen spinosum. In middle cranial fossa, it has an extradural course and divides into anterior frontal branch and posterior parietal branch. The frontal branch is closely related to the motor area of the cerebral cortex. It is the commonest source of extradural hemorrhage and results in hemiplegia of the opposite side. The parietal branch is closely related to the cerebrum and its involvement result in contralateral deafness. 

# Which one of the following is a junction of frontal, parietal, temporal and greater wing of sphenoid bone?   A. Pterion  B. Lambda  C. Vertex  D. Inion # A non synovial joint with dense connective tissue between two bony surfaces is termed as:  A. Synchondrosis  B. Syndesmosis  C. Symphysis  D. Suture

14th MARCH 2019 B.P. Koirala Institute of Health Sciences, Dharan, Nepal 5th year BDS FINAL EXAMINATION, MARCH 2019 Paper - IV  (ORAL & MAXILLOFACIAL SURGERY) Time - 2 Hours  Total Marks: 80 SHORT ANSWER QUESTIONS SECTION - 'A' Maximum Marks - 40 1. Explain the pathophysiology of osteomyelitis of jaws.   (4) 2. Discuss the clinical features of trigeminal neuralgia and enlist different treatment options. (2+3=5) 3. Enlist FOUR clinical features of zygomatic arch fracture. Add a note on Gillies temporal approach to indirect reduction. (2+3=5) 4. Enlist the clinical test to diagnose oro-antral communication and add a note on management of oroantral communication. (2+4=6) 5. Discuss briefly on different types of dislocation and enumerate the surgical procedures for the management of chronic recurrent temporomandibular joint dislocation . (3+3=6) 6. Mention the difference between ridge extension and ridge augmentation procedure ba...

# Moth eaten appearance is seen in all except: A. Osteomyelitis B. Hemorrhagic cyst C. OKC D. Osteosarcoma The correct answer is C. OKC 'Moth eaten appearance' is seen in lesions of bone which shows lytic activity.  Seen in: - Osteomyelitis - Acute suppurative and chronic both - Osteosarcoma - Osteoradionecrosis - Ewing Sarcoma - Langerhans cell histiocytosis - Hemorrhagic cyst

# A radiolucency seen between the maxillary central incisors is most commonly due to: A. Periapical cyst B. Nasopalatine cyst C. Globulomaxillary cyst D. Nasoalveolar cyst The correct answer is B. Nasopalatine cyst Nasopalatine cyst (Incisive canal cyst) - Most common fissural cyst, usually asymptomatic, may complain of tender swelling of palate. Radiographic characteristics- well demarcated round, oval or heart shaped radiolucency between and above maxillary central incisors; rarely just lateral to the midline; lesion crosses midline, teeth are vital. 

# The dentin desensitizing agents that acts by precipitating proteins in dentinal tubular fluid is: (MHCET 2014) A. Strontium chloride B. Potassium oxalate C. Fluoride D. Hydroxyethyl methacrylate The correct answer is A. Strontium chloride. After professional diagnosis, dentinal hypersensitivity can be treated simply and inexpensively by home use of desensitizing dentifrices. Strontium Chloride Dentifrices Ten percent strontium chloride desensitizing dentifrices are found effective in relieving the pain of tooth hypersensitivity. Potassium Nitrate Dentifrices Five percent potassium nitrate dentifrices are found to alleviate pain related to tooth hypersensitivity. Fluoride Dentifrices Sodium monofluorophosphates dentifrices are effective mode of treating tooth hypersensitivity. Strontium chloride is the most important constituent in home care dentifrices intended to be used for the treatment of dentinal hypersensitivity. Topical applicatio...

# Which of the following are true about direct pulp capping? A. Mechanically exposed teeth have a greater success rate than carious exposures B. Final restorative materials do not affect success C. Generally, individual teeth involved in a fixed prosthesis are candidates for direct pulp capping D. All of the above The correct answer is A.  Mechanically exposed teeth have greater success rate than carious exposures.

# The ‘FLUORIDE BOMBS’ is related to: A. A fluoride  capsule with high ppm of fluoride varnish B. A hypoplastic lesion on tooth seen in fluorosis areas C. Undiagnosed hidden caries D. Procedure to treat rampant caries The correct answer is C. Undiagnosed hidden caries. Occult or hidden caries is used to describe such lesion which is not clinically diagnosed but detected only on radiographs. Occult lesions are seen with low caries rate which is suggestive of increased fluoride exposure. It is believed that increased fluoride exposure encourages remineralization and slows down the progress of the caries in the pit and fissure enamel while the cavitation continues in dentin, and the lesions become masked by a relatively intact enamel surface. These hidden lesions are called 'fluoride bombs' or fluoride syndrome.

# Calcium hydroxide is advocated as an inter appointment intracanal medication because of: A. Its ability to dissolve necrotic tissue B. Its antimicrobial property C. Its ability to stimulate hard tissue formation D. Its powerful bleaching effect The correct  answer is B. Its antimicrobial property.  Most studies report culture reversals during the interappointment period when active antibacterial dressing is not used in the root-canal system between appointments. The reversals are due to regrowth of residual bacteria or recontamination by bacterial leakage around the access cavity dressing.  Classical and well-controlled studies (Sundqvist’s group) evaluated the effect of various root-canal treatment procedures on the microbiota both qualitatively and quantitatively. They tested the effect of mechanical preparation, saline or sodium hypochlorite irrigation (0.5%, 5.0%, 5.0% with EDTA), the addition of ultrasonic activation to the irrigation and calc...

# In the carious process, the initial dissolution of the tooth substance by acid takes place in which of the following place? A. Below the dentin Surface B. Below the enamel surface C. On the enamel surface D. Towards the dentin The correct answer is B. Below the Enamel Surface. The top portion of the tooth remains intact and it's the subsurface which looses the minerals. This is the stage where it's called as incipient lesion. Once the top protion breaks, it's called a cavitated lesion.

The correct answers are highlighted in green. # Micelles are the bodies related to:  A. Secretion of hormones  B. Secretion of enzymes  C. Absorption of minerals  D. Absorption of fat # Movements of circular muscles in the stomach is called  A. Digestion  B. Absorption  C. Excretion  D. Peristalsis

Sites Metabolic Pathways Mitochondria Citric acid cycle Oxidative phosphorylation Fatty acid oxidation Electron transfer Synthesis of ketone bodies Ribosomes Protein Synthesis Golgi Complex Glycoprotein synthesis Nucleolus RNA Synthesis Cytoplasm Cholesterol synthesis Glycolysis Fatty acid synthesis Glycogenesis Glycogenolysis HMP shunt Gluconeogenesis In both mitochondria and cytosol Urea Cycle Gluconeogenesis

# Clotting factor common to extrinsic and intrinsic pathway is: A. Factor II B. Factor III C. Factor V D. Factor VII The correct answer is C. Factor V. Prothrombin activator that is formed in intrinsic and extrinsic pathways converts prothrombin into thrombin in the presence of calcium (factor IV).  Once formed thrombin initiates the formation of more thrombin molecules. The initially formed thrombin activates Factor V. Factor V in turn accelerates formation of both extrinsic and intrinsic prothrombin activator, which converts prothrombin into thrombin. This effect of thrombin is called positive feedback effect. 

# Acid etching is done to: A. Decrease microleakage B. Decrease polymerization shrinkage C. Decrease Coefficient of thermal expansion D. Decrease porosity in restorative material The correct answer is A. Decrease microleakage. Acid-etching transforms the smooth enamel into an irregular surface  and increases its surface free energy. When a fluid resin-based material is applied to the irregular etched surface, the resin penetrates into the surface, aided by capillary action. Monomers in the material polymerize, and the material becomes interlocked with the enamel surface.The formation of resin microtags within the enamel surface is the fundamental mechanism of resin-enamel adhesion. As measured in the laboratory, shear bond strengths of composite to phosphoric acid-etched enamel usually exceed 20 megapascals (MPa) and can range up to over 50 MPa, depending on the test method used. Such bond strengths provide adequate retention for a broad variety of procedures and ...

# Iron content in 3M Nickel based steel crowns is: (MAN -01) a) 20% b) 40% c) 60% d) 10% The correct answer is D. 10 %. Composition of stainless steel crowns: Stainless steel (18-8) austentic type of alloy is used. Eg.: Rocky mountain and unitek. Iron -                 87% Chromium - 17% Nickel -         12% Carbon -          0.08 - 1.15% Nickel base crowns. Eg.: Iconel 600 and 3M crowns Iron                     -  10% Chromium -    16% Nickel - 72% others - 2%

# A gingival wall is difficult to obtain in primary molar when it extends too far gingivally in class II cavities because: (MAN-97) a) Facial pulp horn may be exposed b) Inclination of cervical enamel rods occlusally c) Of marked cervical constriction d) Prime contact is broad and flat The correct answer is C. of marked cervical constriction. Gingivally the enamel rods have an occlusal direction in primary teeth so bevel is not required as there will be no unsupported enamel rods. It is difficult to obtain gingival wall when lesion extends too far gingivally in primary molar due to the presence of marked cervical constriction.