Dentosphere : World of Dentistry

# Hypercementosis is the excessive deposition of secondary cementum on the roots. Any tooth may be involved, however, which teeth are most frequently involved? A. Molars B. Incisors C. Premolars D. Canines The correct answer is C. Premolars. Hypercementosis is often confined to the apical half of the root but, in some instances, may involve the entire root. In a large majority of instances, it affects vital teeth, is not associated with any one particular systemic disease, and may be regarded as a dental anomaly. lt may be seen when a tooth has lost its antagonist or when there is a chronic inflammation of the tooth. The premolars are most frequently involved. Next in frequency are the first and second molars. Hypercementosis produces no significant clinical signs or symptoms indicative of its presence. It is seen radiographically as a bulbous enlargement that has surrounding it a continuous and unbroken periodontal membrane space and a normal lamina dura. ...

# Death in Ludwig's angina occurs due to: (MAN -2K) A. Sepsis B. Respiratory obstruction C. Cavernous sinus thrombosis D. Carotid blow-out The correct answer is B. Respiratory obstruction. In Ludwig's angina there is progressive dyspnoea due to backward spread of infection. If not treated, it results in edema of glottis and causes complete respiratory obstruction.

# At what point is herd immunity to a given disease observed? A. After 100% of a population has developed a primary immune response B. After antibiotics have treated all known cases of disease in a population C. After 100% of a population has developed a secondary immune response D. Immediately after 100% of a population has been Immunized E. After enough people in a population have developed a primary immune response so that spread of an infectious agent is curtailed The correct answer is E. After enough people in a population have developed a primary immune response so that spread of an infectious agent is curtailed.  Herd immunity does not require that 100% of a population be immune. Herd immunity requires that enough people in the population have elicited memory cells. Should the pathogen enter the population, the number of people infected will be small because the immunized population will not be able to contract or spread the infection to the n...

# To extend the life of a tungsten carbide bur, the bur should... A. Be moving slow before contacting tooth structure B. Be sterilized with heat sterilization C. Contact tooth structure before rotating D. Be moving fast before contacting tooth structure The correct answer is D. Be moving fast before contacting tooth structure. The lifespan of a tungsten carbide bur can be extended by bringing the bur up to speed  before contacting tooth structure, because it decreases the friction between the bur and the tooth structure thereby decreasing damage to the bur and the pulp. Sufficient rotating speed makes the cutting edge of the bur more efficient even with using light pressure. Heat sterilization corrodes the carbon steel and anneals the cutting edge of the bur.

# In Which dental procedure is a rubber dam most indicated? A. Deep caries B. Direct pulp capping C. Indirect pulp capping D. Preparing a crown The correct answer is: B. Direct Pulp capping.  In direct pulp capping, it is essential to have adequate access, visibility, and isolation of the operating field. Direct pulp capping is indicated if a pin-point pulp exposure is made during cavity preparation. Teeth should be properly isolated to avoid saliva and bacterial contamination during direct pulp caps. Proper isolation of the operating field also allows proper sealing of the cavity of the tooth. 

# The single most important factor in producing cariogenic plaque is: A. High amount of glucose exposure B. High frequency of glucose exposure C. High amount of sucrose exposure D. High frequency of sucrose exposure The correct answer is: D. High frequency of sucrose exposure. High-frequency exposure to fermentable carbohydrates such as sucrose may be the most important factor in producing cariogenic biofilm and ultimately caries lesions. Frequent ingestion of fermentable carbohydrates begins a series of changes in the local tooth environment, essentially changing the composition of the biofilm, thus favoring the growth of highly acidogenic bacteria that eventually leads to caries lesion formation. In contrast, when ingestion of fermentable carbohydrates is severely restricted or absent, biofilm growth typically does not lead to caries lesions. Sucrose in particular allows the formation of extracellular polysaccharides, which render the biofilm viscous and stic...

# The liquid system of glass ionomer restorative material is essentially: A. Polyalkanoic acid B. Phosphoric acid C. Polyacrylic-itaconic acid D. Hydrochloric acid The correct answer is C. Polyacrylic-itaconic acid. COMPOSITION OF GLASS IONOMER CEMENTS Powder/liquid materials Powder -  Sodium aluminosilicate glass with about 20% CaF and other minor additives Liquid - Aqueous solution of acrylic acid/itaconic acid copolymer or Aqueous solution of maleic acid polymer or maleic/acrylic copolymer and Tartaric acid in some products to control setting characteristics Powder/water materials Powder - Glass (as above) + vacuum-dried polyacid (acrylic, maleic or copolymers) Liquid - Manufacturers supply a dropper bottle which the operator fills with water or The manufacturer supplies a dilute aqueous solution of tartaric acid

# Toothbrush trauma (cervical abrasion) usually occurs on: A. Centrals and laterals B. Canines and premolars C. Second and third molar D. First and second molars The correct answer is: B. Canines and premolars. Toothbrush trauma (abrasion) usually occurs on teeth that are the most prominent in the dental arch. Trauma from toothbrushing may result in the following: • Recession of the marginal gingiva • Lacerations of the soft tissues including the attached gingiva and the alveolar mucosa • V-shaped notches in the cervical areas of teeth • Gingival clefts: which are narrow grooves that extend from the crest of the gingiva to the attached gingiva The location of the above alterations is frequently inversely related to the right or left handedness of the patient.

# Which type of pocket is formed by gingival enlargement without destruction of the underlying periodontal tissues? A. Gingival pocket B. Periodontal pocket C. Suprabony pocket D. Infrabony pocket The correct answer is A. Gingival pocket. Deepening of the gingival sulcus may occur by coronal movement of the gingival margin, apical displacement of the gingival attachment, or a combination of the two processes. Pockets can be classified as follows: • Gingival pocket (pseudopocket): this type of pocket is formed by gingival enlargement without destruction of the underlying periodontal tissues. All gingival pockets are suprabony (the base of the pocket is coronal to the crest of the alveolar bone). The sulcus is deepened because of the increased bulk of the gingiva. •Periodontal pocket: this type of pocket occurs with destruction of the supporting periodontal tissues. Progressive pocket deepening leads to destruction of the supporting periodontal tissues and ...

# The source of mineralization for supragingival calculus is: A. Desquamated epithelial cells B. Gingival crevicular fluid C. Phosphatases formed by bacterial plaque D. Saliva The correct answer is D. Saliva. Calculus is dental plaque that has undergone mineralization. It forms on the surfaces of natural teeth and dental prostheses. Saliva is the source of mineralization for supragingival calculus, whereas the serum transudate called gingival crevicular fluid furnishes the minerals for subgingival calculus. • Supragingival calculus: is located coronal to the gingival margin. ft is usually white or pale yellow in color and is hard with a claylike consistency. It is easily removed by professional cleaning. The two most common locations for supragingival calculus to develop are the buccal surfaces of the maxillary molars and the lingual surfaces of the mandibular anterior teeth. Saliva from the parotid gland flows over the facial surfaces of the maxillary m...

# Bone consists of: A. Two-thirds organic matter and one-third inorganic matrix B. One-third organic matter and two-thirds inorganic matrix C. One-half organic matter and one-half inorganic matrix D. Two-thirds inorganic matter and one-third organic matrix The correct answer is D. Two thirds inorganic matter and one-third organic matrix. Bone consists of two-thirds inorganic matter and one-third organic matrix. The inorganic matrix is composed principally of the minerals calcium and phosphate, along with hydroxyl, carbonate, citrate, and trace amounts of other ions, such as sodium, magnesium, and fluoride. The mineral salts are in the form of hydroxyapatite crystals and constitute approximately two-thirds of the bone structure. The organic matrix consists mainly of collagen type l (90%), with small amounts of noncollagenous proteins such as osteocalcin, osteonectin, bone morphogenetic protein, phosphoproteins, and proteoglycans.

# Which one describes the boundaries that define the attached gingiva? A. From the gingival margin to the interdental groove B. From the free gingival groove to the gingival margin C. From the mucogingival junction to the free gingival groove D. From the epithelial attachment to the cementoenamel junction The correct answer is: C. From the mucogingival junction to the free gingival groove. In an adult, normal gingiva covers the alveolar bone and tooth root to a level just coronal to the CEJ. The gingiva is divided anatomically into marginal, attached, and interdental areas. - Marginal or unattached gingiva: is the terminal edge or border of the gingiva surrounding the teeth in collar- like fashion. In about 50% of cases, it is demarcated from the adjacent attached gingiva by a shallow linear depression, the free gingival groove. Usually about 1 mm wide, the marginal gingiva fonns the soft tissue wall of the gingival sulcus. - Attached gingiva: is continuo...

# Water irrigation devices (oral irrigators) have been shown to: A. Eliminate plaque B. Clean nonadherent bacteria and debris from the oral cavity more effectively than toothbrushes and mouth rinses. C. Disinfect pockets for up to 12 hours D. Prevent calculus formation The correct answer is B. Clean nonadherent bacteria and debris from the oral cavity more effectively than toothbrushes and mouth rinses. Oral irrigators for daily home use by patients work by directing a high-pressure, steady or pulsating stream of water through a nozzle to the tooth surfaces. Most often, a device with a built-in pump generates the pressure. Oral irrigators clean nonadherent bacteria and debris from the oral cavity more effectively than toothbrushes and mouth rinses. When used as adjuncts to toothbrushing, these devices can have a beneficial effect on periodontal health by reducing the accumulation of plaque and calculus and decreasing inflammation and pocket depth. Oral irri...

# In implantology, "countersinking" refers to the process of: A. Flaring or enlarging the coronal end of the osteotomy B. Reversing the engine to remove the implant C. Placing the implant in a counterclockwise rotation D. Torquing the abutment to place The correct answer is A. Flaring or enlarging the coronal end of the osteotomy. As one of the final steps in the creation of the osteotomy to receive the implant body, a special bur is activated and inserted into the occlusal end of the osteotomy in order to increase the diameter of the opening slightly or to otherwise shape it. This step is referred to as "countersinking." Countersinking the implant osteotomy is called for by some manufacturers to compensate for very dense cortical bone or to prepare the bone for a particular implant shape (e.g., a flared implant shape at the coronal end). Another of the final steps in the creation of the osteotomy is to place a threaded bur into the osteotomy so...

# Which of the following periodontal diagnoses is MOST COMMON in adults? A. Localized aggressive periodontitis B. Gingival hyperplasia C. Generalized chronic periodontitis D. Necrotizing ulcerative gingivitis E. Plaque associated gingivitis The correct answer is E. Plaque associated gingivitis. Plaque associated gingivitis (marginal gingivitis) is the MOST COMMON periodontal diagnosis. Prolonged exposure to plaque creates an inflammatory response in the gingiva, causing mild gingivitis. Gingival overgrowth can be experienced when taking: - Calcium channel blockers - Phenytoin - Dilantin - Cyclosporine Localized aggressive periodontitis is MOST COMMONLY seen younger patients and is associated with Aggregatibacter actinomycetemcomitans.

# Which of the following is the BEST method for managing a tooth with internal resorption? A. Pulpectomy and root canal therapy B. Extraction C. Svek pulpotomy D. Pulpotomy with calcium hydroxide The correct answer is A. Pulpectomy and root canal therapy. Internal resorption in a tooth requires complete pulp removal followed by a root canal procedure. Pulpotomy does not completely remove the pulp,  so the internal resorption will persist and probably progress if the pulp is not completely removed.

# While attempting to remove a grossly decayed mandibular molar, the crown fractures. What is the recommended next step in order to facilitate the removal of this tooth? A. Use a larger forceps and luxate remaining portion of tooth to the lingual B.  Separate the roots C.  Irrigate the area and proceed to remove the rest of the tooth D. Place a sedative filling and reschedule patient The correct answer is B. Separate the roots. This can be done with a chisel, elevator, or most easily with a bur. Teeth with two or more roots often need to be sectioned into single entities prior to successful removal. A popular method of sectioning is to make a bur cut between the roots, followed by inserting an elevator in the slot and turning it 90° to cause a break. Roots can be removed by closed technique. The surgeon should begin a surgical removal if the closed technique is not immediately successful. Indications for surgical extractions: • After init...

# The root of which tooth is most often dislodged into the maxillary sinus during an extraction procedure? A. Palatal root of the maxillary first premolar B. Palatal root of the maxillary first molar C. Palatal root of the maxillary second molar D. Palatal root of the maxillary third molar The correct answer is B. Palatal root of the maxillary first molar. If an entire tooth or a large fragment of one is displaced into the sinus, it should be removed. If the tooth fragment is irretrievable through the socket, it should be retrieved through a Caldwell-Luc approach ASAP. However, this should be performed only if the dental surgeon is well versed with the procedure, else, the patient should be referred to an oral and maxillofacial surgeon. If a small communication is made with the maxillary sinus during extraction of a tooth, the best treatment is leave it alone and allow the blood clot to form. Post-operative instructions to patient: • Avoid nose blowing for ...

# The ideal time to remove impacted third molars is: A. When the root is fully formed B. When the root is approximately two-thirds formed C. Makes no difference how much of the root is formed D. When the root is approximately one-third formed The correct answer is B. When the root is approximately two thirds formed. Patient would be around the age of 17-21. At this time, the bone is more flexible and the roots are not formed well enough to have developed curves and rarely fracture during extraction. When the root is fully formed, the possibility increases for abnormal root morphology and for fracture of the root tips during extraction.

# A cuplike resorptive area at the crest of the alveolar bone is a radiographic finding of : A. Gingivitis B. Occlusal trauma C. Early periodontitis D. Acute necrotizing ulcerative gingivitis The correct answer is C. Early Periodontitis  Radiographic Changes in Periodontal Disease: • Early periodontitis: areas of localized erosion of the alveolar bone crest (blunting of the crest in anterior regions and a rounding of the junction between the crest and lamina dura in the posterior regions). • Moderate periodontitis: the destruction of alveolar bone extends beyond early changes in the alveolar crest and may include buccal or lingual plate resorption, generalized horizontal erosion or localized vertical defects and possible clinical evidence of tooth mobility. •Advanced periodontitis: the bone loss is so extensive that the remaining teeth show excessive mobility and drifting and are in jeopardy of being lost. There is usually extensive horizontal...

# What is guided tissue regeneration? A. A soft tissue graft used to correct mucogingival junction involvement B. Placement of non-resorbable barriers or resorbable membranes and barriers over a bony defect C. A free gingival graft used to increase the amount of attached gingiva D. Placement of an autograft to treat a bony defect The correct answer is B. Placement of non-resorbable barriers or resorbable membranes and barriers over a bony defect. The method for the prevention of epithelial migration along the cemental wall of the pocket that has gained wide attention is guided tissue regeneration (GTR). This method is based on the assumption that only the periodontal ligament cells have the potential for regeneration of the attachment apparatus of the tooth. GTR consists of placing barriers of different types to cover the bone and periodontal ligament, thus temporarily separating them from the gingival epithelium. Excluding the epithelium and the gingival connectiv...

# Which of the following bacteria are commonly associated with acute necrotizing ulcerative gingivitis (ANUG)? A. Bacteroides forsythus B. Aggregatibacter actinomycetemcomitans C. Actinomyces viscosus D. Porphyromonas gingivalis E. Treponema denticola The correct answer is E. Treponema denticola. Treponema Denticola is associated with acute necrotizing gingivitis/periodontitis (ANUG/ANUP). Acute necrotizing gingivitiss igns/symptoms: - Pain - Interproximal necrosis of the papilla - Bleeding gingiva - Fetid odor - Low-grade fever - Pseudomembrane Acute necrotizing gingivitis risk factors: - Poor oral hygiene - Smoking - Malnutrition - Fatigue - Stress - Immunocompromised patients Aggregatibacter actinomycetemcomitans is most commonly associated with localized aggressive periodontitis. Porphyromonas gingivalis is most commonly associated with chronic periodontitis. Actinomyces viscosus is associated with healthy gingivae. Bacteriodes Forcythus is ass...

# Which of the following creates the phenomena of dentinal plugs? A. Adhesive B. Debris from the smear layer C. Oxalic acid D. Sclerotic dentin E. Primer (form micro/macrotags) Dentinal or smear plugs are composed of the debris from the smear layer. The smear layer is documented to be about 0.5-2mm thick layer of debris with a  mainly granular substructure that entirely coverst he dentin. The surface of the smear layer appears quite irregular. The orifices of dentinal tubules are obstructed by debris tags known as smear plugs or dentinal plugs. These dentinal plugs extend into the tubules to a depth of 1-10 micrometers. The smear layer is reported to reduce dentinal permeability by about 86% due to dentinal plugging. Dentinal plugs are removed by acid etching the tooth surface with phosphoric acid.

# Which of the following hormone's action results in HCl secretion and gastric motility? A. GIP B. Secretin C. Gastrin D. Cholecystokinin The correct answer is C. Gastrin.  Gastrin is stimulated by amíno acids and peptides in lumen, distension. It stimulates HCl secretion and gastric motility. Other hormones of gastrointestinal system: Cholecystokinin : Stimulated by fatty acids, and amino acids in duodenum. Increases pancreatic digestive enzyme secretion and increases bile secretion from the gallbladder. Secretin : Stimulated by a low pH in the duodenum. Increases bicarbonate release from the pancreases and decreases gastric motility and gastric acid secretion. GIP : Stimulated by fat and glucose in the duodenum. Increases insulin release and decreases gastric motility and gastric acid secretion.

# Which of the following viruses is NOT capable of causing cell transformation? A. Retrovirus B. Herpes virus C. Hepatitis B virus D. Human papilloma virus E. Picorna virus The correct answer is E. Picorna virus. Picornavirus is an extremely small, ether- resistant RNA virus which is not capable of cell transformation. This virus can cause several different disease conditions. Diseases caused by Picornavirus include: - Poliomyelitis - Herpangina - Aseptic meningitis - Encephalomyocarditis - Foot-and-mouth disease

# Which of the following is the MOST critical factor determining the prognosis of a periodontally involved tooth? A. Mobility of the tooth B. Probing depth C. Amount of attachment loss D. Presence of furcation involvement The correct answer is C. Amount of attachment loss. The amount attachment loss determines the prognosis of periodontally Compromised teeth. Teeth with severe attachment loss and vertical mobility present a hopeless prognosis and must be extracted to avoid infection that may compromise other teeth. The higher the quantity of attachment, the better the prognosis.

# Elevators are instruments that are designed to: A. Engage the tooth coronal to the cementoenamel junction B. Retract the crestal gingiva before forceps are used C. Reflect a full thickness flap before forceps are used D. Engage the tooth apical to the cementoenamel junction Elevators are instruments used to elevate the tooth out of its socket. Elevators are designed to engage the root portion of the tooth below the cementoenamel junction. Elevators are inserted into the periodontal ligament space, create more room for tooth movement, and help elevate the tooth out of its socket.

# Which of the following is the most UNDESIRABLE property of sodium hypochlorite? A. Tendency to bleach tooth structure B. Reaction with chelating agents C. Smell D. Corrosiveness to endodontic files E. Toxicity to vital tissue The correct answer is E. Toxicity to vital tissue. Sodium hypochlorite in undiluted or excessive amounts is toxic to vital tissues and can cause periapical tissue damage and pain. Sodium hypochlorite is a good disinfectant that is used in dentistry as an endodontic canal irrigant at a diluted concentrations. Sodium hypochlorite is used often used to disinfect gutta percha points prior to placement and obturation of the canal.

# Which of the following describes the 1st step in cavity preparation according to G.V. Black? A Retention form B. Outline form C. Resistance form D. Convenience form The correct answer is B. Outline form. The 1st step in cavity preparation according to G V Black is to establish the outline form. The initial extension or the outline form of the tooth preparation should be visualized preoperatively by estimating the extent of the defect, the preparation form requirements of the amalgam, and the need for the adequate access to place amalgam into the tooth. G.V Blacks various steps of cavity preparation are: - Establish outline form - Obtain retention form - Obtain resistance form - Obtain convenience form

# The implant should be positioned at least ____ away from natural tooth: a) 0.5 mm b) 1.0 mm c) 1.5 mm d) 2.0 mm The correct answer is C. 1.5 mm. When the implant is closer than 1.5 mm to an adjacent root of a tooth, the wedge-shaped vertical defect may become a horizontal defect, creating bone loss on the adjacent tooth root.  Initial vertical bone loss around an implant during the first year of loading varies and ranges from 0.5 to more than 3 mm. this effect is utmost importance because the interseptal bone height in part determines the incidence of presence or absence of interdental papillae between the teeth or implants. As a result, an implant should be at least 1.5 mm from adjacent teeth whenever possible. Natural tooth roots are often close than 1.5 mm to each other. Therefore the ideal mesiodistal implant size is usually less than the natural root dimension. Most often, the ideal implant diameters used to replace the average size anterior tooth co...

# Which of the following is a main ingredient of denture cleaning powder or tablets? a) Hydrogen peroxides b) Detergents c) Sodium perborates d) Alkaline compounds The correct answer is C. Sodium Perborates All the denture cleansing powder and tablets contain detergent, flavouring agent, alkaline compounds and sodium perborat e. The main component is sodium perborate. It decomposes in water to form a peroxide solution which inturn breaks down to liberate oxygen. It is this oxygen bubbles that remove the debris on the denture surfaces. CLICK HERE FOR MORE MCQs

# Most common reason to repeat impression is? a) Improper positioning of tray b) Too less or excess material c) Voids that are irreparable d) Improper mixing The correct answer is A. Improper positioning of tray. The most common reason to repeat an impression is improper positioning of the impression tray. If the tray position is improper, the flange of the impression which lies on the side of deviation will be excessively thick and the flange of the impression opposite to the deviation will be thin. The other reasons are improper consistency, large voids, movement of the tray during setting and too little or too much impression material. CLICK HERE FOR MORE MCQs

# The purpose of relieving mid-palatine area in complete dentures is to prevent: a) Pressure on palate b) Midline fractures in dentures c) Incorrect centric relation d) Resorption of bone The correct answer is A. Pressure on palate. Mid palatine raphe is the median suture area covered by a thin submucousa and the mucosa layer is practically in contact with the underlying bone. For the reason the soft tissue covering the median palatal sutures is non resilient and may need to be relived to avoid trauma from the denture base. CLICK HERE FOR MORE MCQs

# In a case where maxillary canine is missing and we have to make a tooth-supported FPD, the abutment will be: a) Central incisor, Lateral incisor and 1st premolar b) Lateral incisor, 1st premolar 2nd premolar c) Lateral incisor and 1st premolar d) It depends upon periodontal status of remaining teeth The correct answer is A. Central incisor, lateral incisor and first premolar. Missing maxillary canine or mandibular canine (one tooth) come under complex fixed partial dentures and central incisor, lateral incisor and 1'1 premolar acts as abutments, whereas for other teeth(incisors, premolars and molars) the adjacent teeth in relation to the missing tooth are enough to act as abutments. FPD replacing canines can be difficult because the canine often lies outside the inner abutment axis. An edentulous space created by the loss of a canine and any two contiguous teeth is best restored with a RPD. CLICK HERE FOR MORE MCQs

# The posterior tooth that gives a better support is: a) With convergent roots b) Divergent roots c) Conical roots d) Curved roots The correct answer is B. Divergent roots. - Roots with greater labiolingual width than mesiodistal width are preferable to roots that are round in cross section. • Long, irregularly shaped and divergent roots offer great support. • Short, conical and blunted roots offer poor support. CLICK HERE FOR MORE MCQs

# The functional cusps are bevelled in the preparation of posterior cast crowns: a) To reduce the stress at the line angles b) To prevent the fracture of the tooth structure c) For the structural durability of the restoration d) To help in the retention Bevelling of the functional cusp (lingual inclines of maxillary lingual cusps and the buccal inclines of mandibular buccal cusps) is an integral part in obtaining the structural durability of the restoration. - Lack of functional cusp bevel can cause: • A thin area or perforation on the casting. • Overcontouring and poor occlusion of the restoration. • Loss of tooth structure and retention. CLICK HERE FOR MORE MCQs

# The forces acting through a fixed partial denture on the abutment tooth should be directed: a) As far as possible at right angles to the long axis of the teeth b) Parallel to the long axis of the teeth c) By decreasing the mesio-distal dimension d) None of the above The correct answer is B. Parallel to the long axis of the teeth/ Ideally, the forces acting on the abutment tooth should be parallel to long axis of the tooth and should be within the confines of the root. By this, the stress is directed vertically which is well tolerated by the periodontium. Narrowing the buccolingual width of occlusal surfaces of the constructed crowns help to achieve these desirable forces. CLICK HERE FOR MORE MCQs

# Ultrasonic instruments are indicated for each of the following types of patients EXCEPT one. Which is the EXCEPTION? A. Active infectious disease B. Deep periodontal pockets C. Controlled diabetic D. Edematous tissue E.Mildly uncontrolled diabetic Ultrasonic instruments should NOT be used for patients with active infectious disease because the aerosol created by the instruments serves to spread the infection around the operatory. Diabetes and deep periodontal pockets are indications that ultrasonic instrumentation. CLICK HERE FOR MORE MCQs

# Each of the following is associated with full-thickness flaps EXCEPT one. Which is the EXCEPTION? A. Periosteum stays on the bone B. Apical repositioning C. Osseous recontouring D. Dissection of the tissue with a blunt instrument The correct answer is A. Periosteum stays on the bone.  A full thickness flap includes stripping all of the soft tissue (epithelium, connective tissue, periostuem) from the bone. Following placement of the incisions, the flap is dissected using blunt instruments like a # 9 molt to separate the soft tissue from the bone. Full thickness flaps are used when recontouring the osseus structures below or when the gingiva are repositioned apically. CLICK HERE FOR MORE MCQs

# When sharpening instruments, the ______ of the blade should be placed at an angle ________ to the sharpening stone. A. Bevel, 90 B. Bevel, 45 C. Working end, 45 D. Working end, 90° The correct answer is B. Bevel, 45 When sharpening an instrument, the bevel of the blade is placed at an angle of 45° to the sharpening stone. This ensures maximum efficiency of the blade to sharpen the instrument. Instrument sharpening is an important aspect of operative dentistry. Dull instrument are not recommended for carrying out procedures in the oral cavity. Dull instruments are prone to produce more heat, are less efficient and can damage tooth structure. It is recommended to  discard those instruments which cannot be sharpened. CLICK HERE FOR MORE MCQs

# When utilizing four-handed dentistry, the assistant should be positioned... A. Higher than the dentist to facilitate visibility B. Different positions depending on where the dentist is working C. Lower than the dentist for ergonomic posturing D. At the same height because they are a team The correct answer is A. Higher than the dentist to facilitate visibility. In four handed dentistry, the assistant should sit close to the back of patient's chair higher than the dentist to facilitate visibility. This position is suitable for better view of the site, instruments and materials from the mobile cart or instrument tray. It also allows you access to these materials without leaning or overextending your arms. Assistant stools should be placed in a position so that their eye level is 4 to 6 inches higher than the dentist's. CLICK HERE FOR MORE MCQs

# Each of the following dental anomalies is likely to affect anterior teeth EXCEPT one. Which is the EXCEPTION? A. Concrescence B. False microdontia C. False macrodontia D. Gemination E. Dens-in-dente The correct answer is A. Concresence. Concrescence characteristics: Involves the union of two or more teeth through CEMENTUM ONLY. Most common in the permanent molars. It is different from fusion, because it occurs following eruption and never involves enamel and dentin. CLICK HERE FOR MORE MCQs

# In the life cycle of an ameloblast, there are cells that contain Tomes' processes. The cells described are in which of following stages? A. Morphogenic B. Maturative C. Organizing D. Secretory E. Protective The correct answer is D. Secretory. Tomes' process are projections or extensions of ameloblasts formed as the ameloblast moves away from the developing enamel matrix. The ameloblasts secrete secretory granules needed for the production enamel matrix during this phase. Ameloblasts are actively contributing to the enamel matrix formation by combining the secretory granules with the glycoprotein to lay down enamel during the secretory phase. Presence of Tomes' processes is a histological indicator of the secretory phase. CLICK HERE FOR MORE MCQs

# In the mandibular arch where the canines often erupt before the premolars, ________ technique of serial extraction is followed. A. Dewel’s B. Modified Dewel’s C. Tweed’s D. Nance’s The correct answer is: B. Modified Dewel's. Tweed defines it as “the planned and sequential removal of the primary and permanent teeth to intercept and reduce dental crowding problems”. The term “serial extraction” was coined by Kjellgren in 1929 and popularized by Nance (1940) who has been called the ‘father of serial extraction'. Indications of serial extraction: Indications 1. Class I malocclusions with anterior crowding space discrepancy of 10 mm more. 2. Lingual eruption of lateral incisors. 3. Midline shift of mandibular incisors due to displaced lateral incisors. 4. Premature loss of deciduous canine. 5. Abnormal canine root resorption. 6. Severe proclination of mandibular and maxillary interiors with associated crowding. 7. Ectopic eruption. 8....

# Undetectable death of embryo occurs during first few days of conception when exposure range is: A. 0.1 – 0.3 Gy B. 0.4 – 0.7 Gy C. 0.8 - 1 Gy D. 1 – 3 Gy The correct answer is: D. 1-3 Gy. Exposures of 1 to 3 Gy during the first few days after conception are thought to cause undetectable death of the embryo because many of these embryos fail to implant in the uterine wall. The period of organogenesis, when the major organ systems form, is 3 to 8 weeks after conception. The most common abnormalities among the Japanese children exposed early in gestation were reduced growth that persisted through life and reduced head circumference (microcephaly), often associated with mental retardation. Ref: Oral Radiology, Principles and Interpretation, 7th E Page No. 25 CLICK HERE FOR MORE MCQs

# The plasma coating of a Titanium Dental implant (TPS) is done to: A. To increase its acceptance in bone B. To make the Implant Biocompatible C. To avoid contamination of the implant D. To improve implant anchorage power in bone The correct answer is: D. To improve implant anchorage power in bone. Applying calcium phosphate (CaP) coating on implants improves the osteoconductive (osseointegration) properties. Different methods have been developed to coat metal implants with CaP layer such as plasma spraying, biomimetic and electrophoretic deposition. By means of plasma polymerization, positively charged, nanometric thin coating can be applied to implant surfaces. Titanium plasma sprayed (TPS) surface results in increased surface area and it has been proposed that TPS improves implant anchorage power in bone (Osseo integration). CLICK HERE FOR MORE MCQs

# The first bone formed in response to orthodontic loading is: a) Bundle bone b) Composite bone c) Lamellar bone d) Woven bone The correct answer is D. Woven bone. When a force is applied, there is stretching of the periodontal fibres on the tension side with raised vascualarity. This raised vascularity causes mobilization of fibroblasts and osteoblasts into that area, which form osteoid. This lightly calcified bone in due course of time matures to form woven bone. CLICK HERE FOR MORE MCQs

# Incompetent lips refer to a) Inability of the Lips to cover the incisors in the mandibular relaxed position b) Inability of the lips to cover the incisors in occlusion c) The lips come in between the upper and lower incisors d) Tongue thrusts against the lips during swallowing The correct answer is A.  Inability of the Lips to cover the incisors in the mandibular relaxed position Competent Lips :  The lips are in slight contact when the  musculature is relaxed Incompetent Lips : Morphologically short Lips which do not form a lip seal in relaxed state Potentially competent lips: Normal lips that fail to form a lip seal due to proclined upper incisors or increased facial height Everted Lips: Hypertrophied lips with weak muscular tonicity CLICK HERE FOR MORE MCQs

# Which of the following is contraindicated beneath composite resins as liner/ base? A. Calcium hydroxide B. Zinc oxide-eugenol C. Glass ionomer D. None of the above The correct answer is B. Zinc oxide -eugenol. The advantages of ZOE cement are that it gives excellent seal, has a sedative effect on prepared sensitive teeth, cost-effectiveness, and ease of removal of cemented temporary restorations. However, these materials have the disadvantage that eugenol hinders the polymerization of resin cements that are used to fix final restorations. Tooth preparation usually exposes dentin, and hence, luting agents should possess property of being able to bond with the dentin. Eugenol used in cements for fixation of temporary restoration can penetrate into dentin and might affect adhesion of resin cements that are used for fixation of permanent restorations at a later stage. Hence, few authors suggested to use noneugenol cements for fixing interim restorations. Ref:  https://...

# Most commonly fractured cusp is: A. Buccal cusps of maxillary molars B. Buccal cusps of mandibular molars C. Lingual cusps of maxillary molars D. Lingual cusps of mandibular molars The correct answer is D. Lingual cusps of mandibular molars. Ref: Fennis, Willem & Kuijs, Ruud & Kreulen, Cees & Roeters, Joost & Creugers, Nico & Burgersdijk, Rob. (2002). A Survey of Cusp Fractures in a Population of General Dental Practices. The International journal of prosthodontics. 15. 559-63.