Dentosphere : World of Dentistry

 # Listerine is contraindicated in patients taking: A. Phenytoin B. Cyclosporin C. Nifedipine D. Disulfiram The correct answer is D. Disulfiram. Listerine antiseptic and its generic counterparts are approved by the ADA Council on Dental Therapeutics to help prevent and reduce supragingival plaque and gingivitis. The active ingredients in Listerine are methyl salicylate and three essential oils (eucalyptol, thymol, and menthol). Listerine has been shown to be effective in reducing plaque and gingivitis compared with placebo rinses in young healthy adults. Listerine may exacerbate xerostomia because of its high alcohol content, ranging from 21.6% to 26.9%. Listerine is generally contraindicated in patients under treatment for alcoholism who take Antabuse (disulfiram). Listerine may benefit patients who do not tolerate the taste or staining of chlorhexidine and who prefer OTC medicaments that are less expensive and easier to obtain. Reference: Carranza's Clinical Periodontology, 12th ...

 # The only antibiotic in periodontal therapy to which all strains of A. actinomycetemcomitans are susceptible: A. Azithromycin B. Ciprofloxacin C. Cvefidipine D. Metronidazole The correct answer is B. Ciprofloxacin. Ciprofloxacin Pharmacology: Ciprofloxacin is a quinolone that is active against gram-negative rods, including all facultative and some anaerobic putative periodontal pathogens. Clinical Use: Because it demonstrates a minimal effect on Streptococcus species, which are associated with periodontal health, ciprofloxacin therapy may facilitate the establishment of a microflora that is associated with periodontal health. At present, ciprofloxacin is the only antibiotic in periodontal therapy to which all strains of A. actinomycetemcomitans are susceptible. It has also been used in combination with metronidazole. Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 519 CLICK HERE FOR MORE MCQs

 # Which of the following contains most aggressive bacteria penetrating connective tissue and resulting in bone destruction? A. Subgingival unattached plaque B. Subgingival tooth attached plaque C. Subgingival attached plaque D. Supragingival plaque The correct answer is A. Subgingival unattached plaque. The total width of the plaque-free zone varies according to the type of tooth (i.e., it is wider in the molars than in the incisors) and the depth of the pocket (i.e., it is narrower in deeper pockets). It is important to remember that the term plaque-free zone refers only to attached plaque, because unattached plaque contains a variety of gram-positive and gram-negative morphotypes, including cocci, rods, filaments, fusiforms, and spirochetes . The most apical zone contains predominantly gram-negative rods and cocci. Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 285. CLICK HERE FOR MORE MCQs 

 # The predominant immunoglobulin in gingival fluid is: A. IgA B. IgG C. IgM D. IgE The correct answer is B. IgG. High levels of antibodies appear in GCF (in addition to those in the circulation), and these are produced locally by plasma cells in periodontal tissues. Antibodies to periodontal pathogens are primarily IgG, with few IgM or IgA types produced. Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 97 CLICK HERE FOR MORE MCQs

 # Following are the examples of indirect retainers except: A. Occlusal rest B. Auxillary occlusal rest C. Canine rest D. Continuous bar retainers and linguoplates The correct answer is A. Occlusal rest. Continuous clasp : “A metal bar usually resting on the lingual surface of teeth to aid in their stabilization and to act as an indirect retainer”-GPT. Canine rest • If the mesial marginal ridge of the first premolar is close to the fulcrum line, canine rest is used. • This design can be modified by placing the minor connector anterior to the canine. The minor connector hooks back into the cingular rest seat. This increases the efficacy of the indirect retainer (due to increase in distance from the fulcrum line). Types of Indirect Retainers The most commonly used type of indirect retainer is a rest connected to a minor connector. In some cases indirect retention is obtained without a rest. Types: 1. Auxiliary occlusal rest 2. Canine extension from the occlusal rest 3. Canine rest 4....

 # Main advantage of the palatal plate major connector is: A. Thick metal plate B. Thin metal plate C. Surface irregularity of plate D. Corrugated plate The correct answer is D>B.  Advantages: • Intimate contact with the palatal tissues over a large area provides good retention due to the presence of interfacial surface tension. • Provides good vertical support. • Numerous surface corrugations due to very thin metal provide a very natural feel. Reference: Nallaswamy, 2nd Edition, Page No 331 CLICK HERE FOR MORE MCQs

 # Class IV Kennedy classification is: A. A single edentulous area located anterior to remaining natural teeth B. A single edentulous area present anterior to the canine C. A single edentulous area present bilaterally on both halves of the jaw D. A single edentulous area crossing the midline located anterior to the remaining natural teeth The correct answer is D. A single edentulous area crossing the midline located anterior to the remaining natural teeth Class IV: Single, bilateral edentulous area located anterior to the remaining natural teeth. This is a single edentulous area, which crosses the midline of the arch, with remaining teeth present only posterior to it.  Reference: Nallaswamy, 2nd edition, Page no: 272 CLICK HERE FOR MORE MCQs

 # The main purpose of tilting the cast in surveying is to: A. Locate the undercuts B. Locate the line of contour C. Provide the most desirable path of placement D. Aid in designing The correct answer is C. Provide the most desirable path of placement. Tilting the Cast and  Altering the Path of Insertion Some areas of the tooth may form an undercut only when viewed in a different angle. In such cases, the cast can be tilted on a surveyor so that the path of insertion of the denture is altered and the undercuts are present in relation to the new path of insertion. The cast can be tilted only to a maximum of 10°, beyond which it is not advisable because the patient will require excessive mouth opening for insertion and removal. Generally, tilting the cast to obtain a retentive undercut is the least sorted procedure and is not advisable in the presence of other alternatives. Ref: Nallaswamy, 2nd Edition Page No: 402 CLICK HERE FOR MORE MCQs

 # The most common reason for midline fracture of the maxillary denture is due to:  A. Alignment of posterior teeth too far buccally B. Lack of strength of the material itself C. Thin palatal portion of the denture D. Internal porosity which is common in palatal portion The correct answer is A. Alignment of posterior teeth too far buccally. Denture base resins are subjected to a variety of stresses during function: • Midline fractures of dentures during function are considered a flexural fatigue failure due to cyclical deformation of the base during function. This is usually more evident in ill fitting or poorly designed dentures. • Impact fracture may result from patients accidentally dropping the dentures. Ref: Boucher's Prosthodontics, 13th Edition Page 137  CLICK HERE FOR MORE MCQs

 # Zero degree cusp teeth are preferred over anatomic teeth: A. When muscles of mastication is very powerful B. Diabetic patients C. Patients with well developed residual ridge D. Patients with very less retention and stability The correct answer is D. Patients with very less retention and stability. Zero degree teeth are defined as, “Artificial posterior teeth having no cusp angles in relation to the horizontal occlusal surfaces” - GPT. Advantages • In patients with bruxism non-anatomic teeth decrease the forces acting on the basal tissues. • Greater range of movements is possible. • In patients with neuromuscular disorders where accurate jaw relation cannot be recorded, cuspless teeth are preferred. • In cases with highly resorbed ridge, cuspless teeth are preferred as they do not get locked and displace the denture during lateral movements. Disadvantages • Flat occlusal surfaces and artificial contours give an unaesthetic appearance. • Masticatory efficiency is less. • Balanced...

 # Metal margin is preferred over ceramic margin in metal ceramic restoration: A. Margins are easy to prepare for metal during tooth preparation B. Tooth preparation is going to be more conservative C. Only when margin is subgingival D. Marginal adaptation is better in metal margin rather than ceramic margin The correct answer is C. Only when margin is subgingival. Metal ceramics:  These materials require extensive tooth reduction. The junction between the metal and the ceramic is very unaesthetic. For aesthetic reasons the margins of the restoration is placed subgingivally which frequently leads to periodontal problems.  Reference: Nallaswamy, 2nd Edition, Page 495 CLICK HERE FOR MORE MCQs

 # The support of partial denture is usually: A. Tooth support B. Mucosa support C. Occlusal rest support D. Tooth and mucosa support The correct answer is D. Tooth and mucosa support. Watt et al Classification He proposed the classification in 1958. It was based on the type of support derived. • Entirely tooth borne: The entire denture rests on the abutment teeth. • Entirely tissue borne: The entire denture rests on the soft tissue. • Partially Tooth borne and partially tissue borne: These dentures rest on both the teeth and the tissues. Generally most of the removable partial dentures come under this category. Reference: Nallaswamy, 2nd Edition, Page 284 CLICK HERE FOR MORE MCQs

 # ‘Sandwich technique’ of restoration of carious lesion involves application of following materials: A. Dycal/GIC/Composites B. Dycal/GIC/Phosphate C. Phosphate/Miracle mix/Amalgam D. ZOE/Amalgam/Composite The correct answer is A. Dycal/GIC/Composites When composite is placed over an RMGI material, this technique is often referred to as a ‘sandwich’ technique. The potential advantages of this technique are: - The RMGI material bonds to the dentin without the need for a dental adhesive - The RMGI material, because of its bond to dentin and potential for fluoride release (potential anti-cariogenicity), may provide a better seal when used in cases where the preparation extends gingivally onto root structure - The favourable elastic modulus of the RMGI may reduce the effects of polymerization shrinkage stresses. These suggested advantages are considered controversial, as no conclusive published research based on longitudinal clinical trials evaluating the technique is available. Refer...

# The root amputation procedure involving the removal of one half of the crown and one root in a mandibular molar is called as: A. Bi-cuspidization B. Hemisection C. Root resection D. Apicoectomy  The correct answer is B. Hemisection. RADISECTOMY AND HEMISECTION Definition: Radisectomy denotes the removal of one or more roots of a molar. Hemisection refers to sectioning of the crown of a molar tooth, with either the removal of half the crown and its supporting root structure or the retention of both halves, to be used after reshaping and splinting as two premolars. Reference: GROSSMAN’S ENDODONTIC PRACTICE 14TH EDITION, Page NO: 447 CLICK HERE FOR MORE MCQs

 # For a patient with the gingival recession, The best technique of wedging is: A. Piggy back B. Double wedging C. Wedge wedging D. Single wedge The correct answer is A. Piggy Back. Piggy-back wedging technique If the wedge is significantly apical of the gingival margin, a second (usually smaller) wedge may be placed on top of the first to wedge adequately the matrix against the margin. This type of wedging is particularly useful for patients whose interproximal tissue level has receded. Reference: Sturdevant’s Art and Science of Operative Dentistry Second South Asia Edition 2019, Page No: 362 CLICK HERE FOR MORE MCQs

# Which of the following agents is used as a die hardener? A. Cyanoacrylate B. Nail polish C. Volatile relief agents D. Composite resin The correct answer is A. Cyanoacrylate. Gypsum dies are sometimes modified to (1) make them more abrasion-resistant, (2) change the dimensions of the dies, (3) increase the refractoriness of the dies, or (4) produce a combination of these effects. Several means are used to increase the abrasion resistance, including silver plating, coating the surface with cyanoacrylate adhesive , and adding a die hardener to the gypsum. Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 211 CLICK HERE FOR MORE MCQs

 # Following are the factors associated with external root resorption except: A. Grafting of alveolar clefts B. Cysts C. Orthodontic therapy D. Endodontic therapy The correct answer is A. Graft of alveolar clefts. Risk factors associated with severe resorption are: - Shorter than average roots. - Previously traumatized teeth. - Nonvital teeth. - Teeth subjected to excessive forces. - Combination of orthodontic and orthognathic procedures. Reference: Shafer’s Textbook of ORAL PATHOLOGY, 7th Edition, Page No: 930 CLICK HERE FOR MORE MCQs

 # Which of the following is a test for measuring hardness? A. Knoop B. Toughness C. Yield strength D. Resilience The correct answer is A. Knoop. The tests most frequently used in determining the hardness of dental materials are known by the names Barcol, Brinell, Rockwell, Shore, Vickers, and Knoop. Selection of the test should be determined on the basis of the material being measured. The Knoop hardness test employs a diamond-tipped tool. The impression is rhombic in outline, and the length of the largest diagonal is measured. The load is divided by the projected area to give the Knoop hardness number (usually abbreviated as HK or KHN). Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 64 CLICK HERE FOR MORE MCQs

 # The mechanism of adhesion of glass ionomer cement restoration with tooth surface is by means of: A. Carboxyl group of polymer chains B. Chelates with metal ion C. C=C double bond D. Hydroxyl group The correct answer is A. Carboxyl group of polymer chains. Glass ionomers bond to tooth structure by chelation of the carboxyl groups of the polyacrylic acids with the calcium in the apatite of the enamel and dentin, in a manner similar to polycarboxylate cement. Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 321 CLICK HERE FOR MORE MCQs

 # During the setting of alginate impression materials: A. Trisodium phosphate reacts preferentially with calcium sulfate B. Trisodium phosphate reacts preferentially with sodium alginate C. The colloidal gel state changes to a sol D. The material in contact with the soft tissues set last The correct answer is. A. Trisodium phosphate reacts preferentially with calcium sulfate A water-soluble phosphate salt (e.g., trisodium phosphate) is added to the composition as a retarder to extend the working time. The strategy is that the calcium ions will react preferentially with the phosphate ions in the solution. Thus, the rapid reaction between calcium ions and the soluble alginate is deferred until phosphate ions from trisodium phosphate are exhausted. The amount of retarder is adjusted to provide the proper setting time. A similar gelation process is expected with the modified alginate product. Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, ...

# Ease with which impression can be poured without bubble formation is related to: A. Hardness of impression material B. Resiliency of impression material C. Contact angle of the die material with the impression material D. Surface contamination The correct answer is C. Contact angle of the die material with the impression material. When gypsum products are mixed with water to pour dental models in various types of impressions, wetting must occur between gypsum and the impression to ensure good surface quality of the gypsum model. The basic ingredient of the most popular silicone-based elastomeric impression material today is considered to be hydrophobic, because a contact angle of greater than 90° is observed when an aqueous medium is poured into this elastomeric mold. To improve the wettability of the set impression material by a gypsum-water mixture, the operator usually sprays a surfactant (also called debubblizer). The most direct approach by the manufacturer is to incorporate a w...

# Which portion of the flame is used while soldering? A. Cold mixing zone B. Partial combustion zone C. Tip of the reducing zone D. Oxidizing zone The correct answer is C. Tip of reducing zone. The next zone, dimly blue and located just beyond the tip of the green combustion zone, is the reducing zone. This is the hottest part of the flame, and it should be kept constantly on the alloy during melting. The outer cone (oxidizing zone) is the area in which combustion occurs with the oxygen in the air. Under no circumstances should this portion of the flame be used to melt the alloy. Not only is its temperature lower than that of the reducing zone but it also oxidizes the alloy. Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 221 CLICK HERE FOR MORE MCQs

 # When porcelain is baked, is backed against metal, it should possess a: A. High fusion expansion B. Linear coefficient of thermal expansion less than, but close to that of the metal C. Linear coefficient of thermal expansion greater than, but close to that of the metal D. Linear coefficient of thermal expansion greater than that of the metal The correct answer is B.: Linear coefficient of thermal expansion less than, but close to that of the metal The metal and porcelain should be selected with a slight mismatch in their coefficient of thermal contraction (the metal CTC being slightly higher) so that the metal contracts slightly more than the porcelain on cooling from the firing temperature to room temperature. This mismatch leaves the porcelain adjacent to the metal in a state of residual compression, which effectively protects the metal-ceramic restoration against fracture of the veneering ceramic. Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th E...

 # The act of smoothening the surface and margin of amalgam restoration is known as: A. Condensation B. Burnishing C. Trituration D. Amalgamation The correct answer is B. Burnishing. After carving is completed, the surface of the restoration should be smoothed. This may be accomplished by judiciously burnishing the surface and margins of the restoration. Burnishing of the occlusal anatomy can be accomplished with a ball burnisher. Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 350 CLICK HERE FOR MORE MCQs

 # The principal ingredient of modeling plastic is: A. Waxes B. Zinc oxide C. Aluminium oxide D. Silicon oxide The correct answer is A. Waxes. In general, impression compounds (modelling plastic) are composed of a mixture of waxes, thermoplastic resins, filler, and a coloring agent. Shellac, stearic acid, and gutta-percha are added to improve plasticity and workability. The waxes or resins in the impression compound are the principal ingredients of the matrix. Filler is added to increase the viscosity at temperatures above that of the mouth and to increase the rigidity of the compound at room temperature. Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 178 CLICK HERE FOR MORE MCQs

# Chemically gypsum is: A. Calcium sulphate dihydrate B. Calcium aluminofluorosilicate C. Calcium carbonate D. Magnesium carbonate The correct answer is A. Calcium sulphate dihydrate. Gypsum (CaSO4•2H2O; calcium sulfate dihydrate) is a mineral mined in various parts of the world, but it is also produced as a by-product of flue gas desulfurization in some coal-fired electric power plants. Various crystalline forms of gypsum, such as selenite and alabaster, exist in nature. Gypsum products are supplied as fine hemihydrate powders that are produced by heating ground gypsum particles. After mixing with water, the mixture reverts back to gypsum. This unique property of gypsum products has led to numerous applications through history. Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition Page no: 182 CLICK HERE FOR MORE MCQs

 # Serial extraction is indicated primarily in: A. Class I malocclusion B. Class II malocclusion C. Class III malocclusion D. Lower anterior crowding only The correct answer is D. Lower anterior crowding only. Serial extraction is directed toward severe dental crowding. For this reason, it is best used when no skeletal problem exists and the space discrepancy is large-greater than l0mm per arch. If the crowding is severe, little space will remain after the teeth are aligned, which means there will be little tipping and uncontrolled movement of the adjacent teeth into the extraction sites. If the initial discrepancy is smaller, more residual space must be anticipated. It is unwise to start serial extraction in a child who has a skeletal problem, because the closure of extraction spaces would be affected by how the skeletal problem was being addressed. Serial extraction treatment begins in the early mixed dentition with extraction of primary incisors if necessary, followed by extract...

# The eruption of permanent teeth in cases of extremely early loss of deciduous teeth  will result in: A. No change in the time of eruption B. Early eruption of the permanent teeth C. Delayed eruption of the permanent teeth D. A class II division 1 malocclusion The correct answer is C. Delayed eruption of the permanent teeth. Sometimes incisors fail to erupt even when there is no retained or overlying primary tooth or supernumerary  teeth present. Changes in the overlying keratinized tissue occur in long-standing edentulous regions, and this contributes to slow eruption of a permanent incisor when its predecessor was lost prematurely.  Ref: Comtemporary Orthodontics, Proffit 4th Edition, Page 450 CLICK HERE FOR MORE MCQs

 # Which of the following are typical consequences of dental crowding; assuming no primary teeth has been lost prematurely? A. Overlapping of lower incisors B. Palatal displacement of upper canines C. Impaction of 15 and 25 between first premolars and first molars D. Mesial tipping of 16 and 26 The correct answer is A. Overlapping of lower incisors. A child with a generalized arch length discrepancy of 2-4mm and no prematurely missing primary teeth can be expected to have moderately crowded incisors. Unless the incisors are severely  protrusive, the long-term plan would be generalized expansion of the arch to align the teeth. Contemporary Orthodontics, Proffit, Fourth Edition Page 247 CLICK HERE FOR MORE MCQs

 # If a first molar is lost, the second molar drifts to the: A. Distal B. Mesial  C. Buccal D. Lingual The correct answer is B. Mesial. When a first permanent molar is lost during childhood or adolescence and not replaced, the second molar drifts  mesially and the premolars often tip distally and rotate as space opens between them.  Ref: Contemporary Orthodontics, Fourth Edition, Page 639. CLICK HERE FOR MORE MCQs

 Name of Dental Clinic: Shanti Pharmacy and Advance Dental Care Address (Full): Biratnagar, Hospital chowk Year of Establishment: 2071 Name of the chief Dental Surgeon: Dr Ravi Acharya CONTACT NUMBER: 9842044842 CLICK HERE TO VIEW ALL DENTAL CLINICS OF PROVINCE NO 1

 # Best X ray view for TMJ is: A. Lateral skull B. Lateral oblique C. Transpharyngeal D. Panoramic The correct answer is C. Transpharyngeal. Transpharyngeal: Main indications The main clinical indications include: - TMJ pain dysfunction syndrome - To investigate the presence of joint disease, particularly osteoarthritis and rheumatoid arthritis - To investigate pathological conditions affecting the condylar head, including cysts or tumours - Fractures of the neck and head of the condyle. CLICK HERE FOR MORE MCQs

 Name of Dental Clinic: Namaste Dental & Oral Health Care Center Pvt Ltd Address (Full) : Triyuga municipality - 11, Gaighat, Udaypur Year of Establishment: 2020 Name of the chief Dental Surgeon: Dr. Niraj Kumar Dev CONTACT NUMBER: 9817706162 CLICK HERE TO VIEW ALL DENTAL CLINICS OF PROVINCE NO 1

 Name of Dental Clinic: Lovely Dental Care  Address (Full) : Sunargaun Marg , Khasi bazar, Kalanki Year of Establishment: 2078 Name of the chief Dental Surgeon: Dr. Pratik Prabhat Gautam  CONTACT NUMBER: 9860900536 CLICK HERE TO VIEW ALL DENTAL CLINICS OF BAGMATI PROVINCE

 Name of Dental Clinic:  Delight Dental care Address (Full) : Tilottama 5, manigram, butwal Year of Establishment:  2021 Name of the chief Dental Surgeon: Dr. Pratima Pathak CONTACT NUMBER:  9849001931 CLICK HERE TO VIEW ALL DENTAL CLINICS OF LUMBINI PROVINCE

CLICK HERE TO VIEW ALL PAST QUESTIONS COLLECTIONS OF LOK SEWA AAYOG  1. Rank the following dental materials in order of increasing values of their coefficient of thermal expansion: dental amalgam, human teeth, porcelain and unfilled acrylic plastics A. Human teeth, porcelain, dental amalgam and unfilled acrylic plastics B. Porcelain, human teeth, unfilled acrylic plastics and dental amalgam C. Porcelain, human teeth, dental amalgam and unfilled acrylic plastics D. Human teeth, porcelain, unfilled acrylic plastics and dental amalgam 2. A metal that expands on solidification from the molten state is: A. Gold B. Silver C. Bismuth D. Copper 3. The principal ingredient of an irreversible hydrocolloid impression is: A. Agar B. Tri sodium phosphate C. Sodium alginate D. Colliodal silica 4. One of the best agents used in successful pulp capping is: A. Copper cement B. Calcium hydroxide C. Amalgam D. Zinc oxide 5. Silicone differs from polyether pol...