Dentosphere : World of Dentistry

Refractory periodontitis is aggravated by: A. Areca nut chewing B. Smoking C. Menstruation D. Hormone PG and oestrogen The correct answer is B. Smoking. The impact of cigarette smoking on the long-term effects of periodontal therapy in a population undergoing Supportive Periodontal Therapy (SPT) has been reported. Smokers displayed less favorable healing responses both at re-evaluation and during a 6-year period of SPT (Baumert-Ah et al. 1994). This was confirmed in another study in which higher percentages of heavy smokers experienced more multiple (≥9) residual pockets (≥5 mm) than non-smokers both after active periodontal therapy (31.2% versus 7.3%, respectively) and after 11 years of SPT (52.4% versus 14.8%, respectively) (Matuliene et al. 2008). In this study, heavy smoking was found to be a significant risk factor for periodontitis progression. Moreover, smoking was the main statistically significant risk factor for the recurrence of periodontitis after 10.5 years of SPT in the 8...

# After curettage, re-epithelialization occurs in: A. 1-2 days B. 2-3 days C. 2-7 days D. Two weeks The correct answer is C. 2-7 days. Immediately after curettage, a blood clot fills the pocket area, which is totally or partially devoid of epithelial lining. Hemorrhage is also present in the tissues with dilated capillaries and abundant polymorphonuclear leukocytes, which appear on the wound surface. This is followed by a rapid proliferation of granulation tissue with a decrease in the number of small blood vessels as the tissue matures. The restoration and epithelialization of the sulcus generally require 2 to 7 days, and restoration of the junctional epithelium occurs in animals as early as 5 days after treatment. Immature collagen fibers appear within 21 days. Healthy gingival fibers that are inadvertently severed from the tooth and tears in the epithelium are repaired during the healing process.  CLICK HERE FOR MORE MCQs

 # With the increase of age, keratinization of gingiva: A. Increases B. Decreases C. Remains same D. None of the above The correct answer is B. Decreases. Thinning and decreased keratinization of the gingival epithelium have been reported with age. The significance of these findings could mean an increase in epithelial permeability to bacterial antigens, a decreased resistance to functional trauma, or both contributing to increased vulnerability of the gingiva to trauma and periodontal disease in older adults. CLICK HERE FOR MORE MCQs

 # Who was the first to band the teeth for active tooth movements? A. Pierre Fauchard  B. Henry A. Baker C. William and Magill  D. Emerson C. Angel The correct answer is C. William and Magill. CLICK HERE FOR MORE MCQs

 # Who advocated the use of finger pressure to align irregular teeth? A. Edward Hartley Angle B. Calvin Case C. Aulius Cornelius Celsius D. PR Begg The correct answer is C. Aulius Cornelius Celcius. Aulius Cornelius Celsus (25 BC–50 AD) described finger pressure to move teeth in his work “De Re Medicina.” CLICK HERE FOR MORE MCQs

 # Who is the founder of modern dentistry? A. Edward H angle B. Norman Kingsley C. Aulius Cornelius Celsius D. Pierre Fauchard The correct answer is: D. Pierre Fauchard. Pierre Fauchard (January 2, 1679 – March 21, 1761) was a French physician, credited as being the "father of modern dentistry". He is widely known for writing the first complete scientific description of dentistry, Le Chirurgien Dentiste ("The Surgeon Dentist"), published in 1728. The book described basic oral anatomy and function, signs and symptoms of oral pathology, operative methods for removing decay and restoring teeth, periodontal disease (pyorrhea), orthodontics, replacement of missing teeth, and tooth transplantation.  CLICK HERE FOR MORE MCQs

 # Bilateral balanced occlusion concept is given by: A. Von Spee and Monson B. GV Black C.  D Van D. Sturdevant The correct answer is A. Von Spee and Monson. This is a type of occlusion that is seen when simultaneous contact occurs on both sides in centric and eccentric positions. Bilateral balanced occlusion helps to distribute the occlusal load evenly across the arch and therefore helps to improve stability of the denture during centric, eccentric or parafunctional movements. For minimal occlusal balance, there should be at least three points of contact on the occlusal plane. More the number of contacts, better the balance. Bilateral balanced occlusion can be protrusive or lateral balance. There are two types of compensating curves namely: • Anteroposterior curves • Lateral curves Curve of Spee, Wilson’s curve and Monson’s curve are associated only with natural dentition. In complete dentures compensating curves similar to these curves should be incorporated to produce balan...

 # The advantage of metal base denture is: A. Increase in tissue tolerance B. Easy laboratory procedure C. Rebasing and relining are quite easy D. Increase in restorative cost The correct answer is A. Increase in tissue tolerance. Advantages of metal denture base Mandibular dentures are heavier. So the retention and stability are improved. Improved thermal conductivity gives good sensory interpretation. They are strong even in thin sections. Thin sections are very comfortable for the patient. Easier to maintain. CLICK HERE FOR MORE MCQs

 # Indirect retainers of partial denture: A. Engages undercut areas B. Most effective when close to direct retainer C. Must be constructed with flexible materials like plastics D. Should resist rotatory forces about fulcrum The correct answer is D. Should resist rotatory forces about fulcrum. Indirect retainers of a partial denture are designed to prevent rotational movement of the denture around the fulcrum line. They help stabilize the denture and distribute occlusal forces more evenly. The correct function of indirect retainers is to resist these rotatory forces about the fulcrum. Therefore, the correct answer is: D. Should resist rotatory forces about fulcrum. When the distal extension denture base is dislodged from its basal seat, it tends to rotate around the fulcrum lines. Theoretically, this movement away from the tissues can be resisted by activation of the direct retainer, the stabilizing components of the clasp assembly, and the rigid components of the partial denture fr...

 # The midline fracture of the maxillary denture are mainly due to: A. Teeth set too buccally B. No midline relief C. Ridge resorption D. All of the above Midline fractures of the maxillary denture are primarily due to multiple factors that can contribute to the weakening of the denture structure. These factors include: Teeth set too buccally: This can cause an uneven distribution of occlusal forces, leading to increased stress on the midline of the denture. No midline relief: Lack of relief in the midline area can result in stress concentration, particularly during functional movements. Ridge resorption: Loss of alveolar ridge height and support can lead to increased flexure and eventual fracture of the denture. Given that all these factors can contribute to the midline fracture of the maxillary denture, the correct answer is: D. All of the above. Several factors have been attributed to be the cause of midline fracture i.e. flexural fatigue resulting from cyclic deformation and ...

 # Cavosurface margin angulation in chamfer finish line is: A. Always 90 degree B. 90 degree or less than 90 degree C. 90 degree or more than 90 degree D. 120 degree The correct answer is C. 90 degree or more than 90 degree. Chamfer is an obtuse-angled finish line. Indicated where metal forms the margin of a restoration, e.g. complete metal crown. Should not be given for porcelain restorations as the obtuse angle produces shearing forces which is not well tolerated by porcelain. It is prepared using a round-end tapering diamond. This is produced by sinking in half the diamond into the tooth. The tip produces the chamfer while the sides give the necessary taper to the axial surface.  Cavosurface angle of less than 90 degree produces a lip of unsupported enamel which fractures easily. CLICK HERE FOR MORE MCQs

# Which of the following is a nutritional deficiency anemia? A. Aplastic anemia B. Sickle cell anemia C. Spherocytosis D. Megaloblastic anemia # Megaloblastic anemia is related to: A. Folic acid and Vit. 12 deficiency B. Iron deficiency C. Vit. C deficiency D. Vit. K deficiency

 # A prepared cavity is best protected from moisture by: A. Cotton rolls  B. Saliva ejector C. Rubber dam  D. Paper napkin The correct answer is C. Rubber dam. It is not possible to properly accomplish operative dentistry without control of mouth moisture. Moisture control refers to the exclusion of saliva, gingival sulcular fluid, and gingival bleeding from the operating field. It also involves preventing or limiting the spray from the handpiece and restorative debris from being swallowed or aspirated by the patient. he rubber dam, suction devices, and absorbents are variously effective in controlling moisture. Use of the rubber dam as an optimum means of gaining moisture control is recommended. CLICK HERE FOR MORE MCQs

  # The finish line used in complete metal cast crown is:  A. Chamfer  B. Chamfer with bevel  C. Feather Edge  D. Shoulder The correct answer is A. Chamfer. Indications of Chamfer Finish Line - Cast metal restorations - Lingual aspect of metal ceramics  Advantages of Chamfer finish line: - Conservative  - Good marginal adaptation - Provides bulk Disadvantages of Chamfer finish line: - Improper fabrication may result in an unsupported tip CLICK HERE FOR MORE MCQs

 # The best surface for a macrofilled composite resin is achieved by: A. Allowing polymerization to occur against a mylar matrix B. Use of a green stone C. Use of an extra fine silicone carbide disc D. Use of a white stone The correct answer is A. Allowing polymerization to occur against a mylar matrix. Finishing of composite resins is best done after 24 hours during which time the polymerization is complete. However, if a subsequent appointment is not desired finishing procedures can be started 15 minutes after curing. The initial contouring can be done with a knife or diamond stone. The final finishing is done with rubber impregnated abrasives or rubber cup with polishing pastes or aluminium oxide disks. The best finish is obtained when the composite is allowed to set against a matrix or mylar strip. CLICK HERE FOR MORE MCQs

 # Silicone differs from polyether polymer with respect to: A. Affinity for water B. Place and time of one C. Area of one D. Cost effectiveness The correct answer is A. Affinity for water. One of the disadvantages of the silicone impression materials (including condensation silicones) is their inherent hydrophobic nature. A nonionic surfactant can be added to the paste in the manufacturing process to render a degree of hydrophilicity to the surface of the material. This surfactant migrates toward the surface of the impression material and has its hydrophilic segment oriented toward the surface—a phenomenon that makes the surface more wettable by water. These impression materials still require a dry field for impression making. Pouring the set impression with a gypsum forming mixture is facilitated because the wet stone has a greater affinity for the hydrophilic surface. The clinical significance of hydrophilic additives is discussed in subsequent sections. CLICK HERE FOR MORE MCQs

 # One of the best agents used in successful pulp capping is: A. Copper cement B. Calcium hydroxide C. Amalgam D. Zinc oxide The correct answer is B. Calcium hydroxide. Calcium hydroxide, because of its high pH value, acts as a pulp irritant and stimulates reparative dentine formation . It is also used as a pulp-capping agent, both in direct and indirect pulp capping. CLICK HERE FOR MORE MCQs

 #  The principal ingredient of an irreversible hydrocolloid impression is: A. Agar B. Tri sodium phosphate C. Sodium alginate D. Colloidal silica The correct answer is C. Sodium alginate. The chief active ingredient in the alginate impression materials is one of the soluble alginates, such as sodium, potassium, or triethanolamine alginate. The diatomaceous earth acts as a filler to increase the strength and stiffness of the alginate gel. It also produces a smooth texture and ensures the formation of a firm gel surface that is not tacky. CLICK HERE FOR MORE MCQs  

 # A metal that expands on solidification from the molten state is: A. Gold B. Silver C. Bismuth D. Copper The correct answer is C. Bismuth. Elemental bismuth is denser in the liquid phase than the solid, a characteristic it shares with germanium, silicon, gallium, and water. Bismuth expands 3.32% on solidification; therefore, it was long a component of low-melting typesetting alloys, where it compensated for the contraction of the other alloying components to form almost isostatic bismuth-lead eutectic alloys. CLICK HERE FOR MORE MCQs

 A Soviet General Practitioner, Leonid Ivanovich Rogozov , had developed appendicitis while at Novolazarevskaya Station in April 1961, and being the only medical professional there at the time, had to perform his own appendectomy.  Leonid Ivanovich Rogozov performing self Appendectomy On the morning of 29 April 1961, Rogozov experienced general weakness, nausea, and moderate fever, and later pain in the lower right portion of his abdomen. None of the possible conservative treatments helped. By 30 April signs of localised peritonitis became apparent, and his condition worsened considerably by the evening. Mirny, the nearest Soviet research station, was more than 1,000 miles from Novolazarevskaya. Antarctic research stations of other countries did not have an aircraft available. Severe blizzard conditions prevented aircraft landing in any case. Rogozov had no option but to perform an operation on himself. The operation started at 02:00 local time on 1 May with the help of a...

  # The upper denture falls when the patient opens his mouth wide. This is due to: A. Thick labial flange B. Over extended borders C. Thick distobuccal flange D. Poor peripheral seal The correct answer is C. Thick distobuccal flange The thickness of distobuccal flange of maxillary denture must be adjusted to accommodate the ramus, coronoid process and the masseter. If the flange is too thick, the coronoid process will push the denture out of place during opening or lateral movements of mandible. CLICK HERE FOR MORE MCQs

  # Posterior palatal seal is recorded when the head is bent at: A. 15 degree B. 30 degree C. 45 degree D. 60 degree The correct answer is B. 30 degree. In conventional method of recording posterior palatal seal, the patient is seated in an upright position. In fluid wax technique, posterior palatal seal is recorded when the head is bent at 30 degree. CLICK HERE FOR MORE MCQs