NBDE Part II – (Fall2022/2024) Exam 100% Solved

Which of the following best explains why the renal excretion of salicylic acid is increased in an alkaline urine? A. The urine volume is decreased. B. The percentage of salicylic acid that is ionized in urine is increased. C. The percentage of salicylic acid that is ionized in urine is decreased. D. Decreasing urine pH usually increases the renal excretion of weak acids. - ANSWER-B. The percentage of salicylic acid that is ionized in urine is increased. X-rays are produced when A. Protons strike the anode. B. Electrons strike the anode. C. The anode is heated above 3,000 degrees Centigrade. D. The filament becomes positively charged. - ANSWER-B. Electrons strike the anode. Primary crown mineralization (calcification) generally begins A. In the third to sixth week in utero. B. In the second trimester. C. In the third trimester. D. At birth. - ANSWER-B. In the second trimester. Which of the following best describes the usual behavioral characteristics of a child who has Down syndrome? A. Crying and stubborn B. Hyperactive and disoriented C. Smiling, affectionate, and easily distracted D. Fearful and unresponsive to verbal communication - ANSWER-C. Smiling, affectionate, and easily distracted A member of the dental staff routinely fails to clean up his work area. Which of the following best exemplifies an assertive message that could be made by a co-worker? A. If you refuse to do your part, I'm just going to have to report the situation to the boss. B. When you don't help with the clean-up, it makes me angry because I have to do both your work and my own. C. I'm tired of cleaning up your mess! D. I hope you'll remember to help me clean up today. E. Is something bothering you? You sometimes forget to clean up. - ANSWER-B. When you don't help with the clean-up, it makes me angry because I have to do both your work and my own. The crown of an endodontically-treated maxillary lateral incisor is fractured near the gingival margin. The coronal end of the silver cone used in filling that canal is visible at that level. The findings reveal that the existing root canal filling meets all criteria to be judged successful. Which of the following is the best way to obtain the needed post space? A. To prepare it alongside the silver cone using burs and Peeso reamers. B. To carefully grind away the coronal part of the silver cone using round burs or end-cutting burs. C. To remove the silver cone and re-treat the canal using a gutta-percha technique, and then to create the needed post space. D. To remove the silver cone, notch it 4 mm from the apical end, coat it with freshly mixed sealer, replace it in the canal, and "twist-off" the coronal segment. - ANSWER-C. To remove the silver cone and re-treat the canal using a gutta-percha technique, and then to create the needed post space. After receiving one cartridge of a local anesthetic, a healthy adult patient became unconscious in the dental chair. The occurrence of a brief convulsion is A. Pathognomonic of grand mal epilepsy. B. Consistent with a diagnosis of syncope. C. Usually caused by the epinephrine in the local anesthetic. D. Pathognomonic of intravascular injection of a local anesthetic. - ANSWER-B. Consistent with a diagnosis of syncope. The axial wall of an occlusolingual amalgam preparation on a maxillary molar should be in dentin and A. Parallel to the dentinoenamel junction. B. Parallel to the long axis of the tooth. C. At an acute angle with the pulpal floor. - ANSWER-A. Parallel to the dentinoenamel junction. During the mixed dentition stage, which of the following appliances should be used as a space maintainer for missing primary molars in the mandibular arch? A. Distal shoe B. Nance holding arch C. Passive lingual arch D. Removable acrylic functional - ANSWER-C. Passive lingual arch Accepted methods for closing a diastema between maxillary central incisors include using either a removable appliance with finger springs or A. A rubber elastic around the two teeth. B. A steel ligature around the two teeth. C. Bonded brackets with intertooth traction. - ANSWER-C. Bonded brackets with intertooth traction. Each of the following developmental cysts appears on radiographs EXCEPT one. Which one is this EXCEPTION? A. Nasolabial B. Median palatal C. Globulomaxillary D. Nasopalatine - ANSWER-A. Nasolabial When trying-in a porcelain fused-to-metal crown, the dentist observes that the gingival-margin finish-line integrity is excellent, but that the occlusal surface is 1 mm too high. Which of the following is the most probable cause? A. Incorrectly related casts B. Proximal contacts being too tight C. A distortion of the metal during firing D. An expansion of the porcelain during firing - ANSWER-A. Incorrectly related casts The Health Belief Model attempts to explain patient recommendations by A. Examining patients' perceptions of disease-seriousness and of the treatment effectiveness. B. Focusing on the doctor-patient relationship. C. Emphasizing the barriers that are external to behavior D. Change, for example, payment mechanisms. E. Focusing on patients' skills at carrying out recommendations. - ANSWER-A. Examining patients' perceptions of disease-seriousness and of the treatment effectiveness. Which of the following represents the MOST effective way of encouraging a child to floss regularly? A. Presenting a message that concerns the potential loss of teeth, should the patient not floss. B. Arranging for the child to earn privileges for flossing. C. Repeating periodically the message on the value of flossing. D. Providing written material that explains the mechanism of flossing. - ANSWER-B. Arranging for the child to earn privileges for flossing. In an ideal Class V cavity preparation for amalgam in a mandibular premolar, retention form is gained A. Into the mesial and distal walls. B. In the mesial and occlusal line angles. C. In the axio-occlusal and axiogingival line angles at the expense of the axial wall. D. In the axio-occlusal and axiogingival line angles at the expense of the occlusal and gingival walls. - ANSWER-D. In the axio-occlusal and axiogingival line angles at the expense of the occlusal and gingival walls. Which of the following systems is thought to malfunction in the hereditary form of angioneurotic edema? A. C-1 esterase B. C-1q inhibitor C. CH50 consumption D. Serine phosphatase E. Complement synthetase - ANSWER-A. C-1 esterase Following a bilateral mandibular fracture in the canine region, the anterior fragment of the mandible is displaced posteriorly by the action of the geniohyoid and by which other muscles? A. Thyrohyoid and mylohyoid only B. Genioglossus and mylohyoid C. Thyrohyoid, mylohyoid, and anterior bellies of the digastric D. Genioglossus and anterior bellies of the digastric - ANSWER-D. Genioglossus and anterior bellies of the digastric The number of persons who die each year from oral cancer in the United States approximates A. 2000 B. 4000 C. 8000 D. 16000 - ANSWER-C. 8000 Each of the following parameters has an effect on the distribution of a drug EXCEPT one. Which one is this EXCEPTION? A. The intrinsic activity of the drug B. The binding of a drug to plasma proteins C. The blood flow to various organs and tissues D. The relative solubility of the drug in the tissues - ANSWER-A. The intrinsic activity of the drug Which of the following is MOST appropriate for testing differences between the means of two groups? A. Chi-square test B. Multiple regression analysis C. Correlation coefficient analysis D. Students t-test - ANSWER-D. Students t-test A patient was administered a flow rate of 4 liters of oxygen and 2 liters of nitrous oxide. What percentage of nitrous oxide did the patient inhale? A. 0.25 B. 0.33 C. 0.5 D. 0.66 - ANSWER-B. 0.33 When a removable partial denture is terminally seated, the retentive clasp tips should A. Be invisible. B. Exert no force. C. Apply retentive force into the body of the teeth. D. Resist torque through the long axis of the teeth. - ANSWER-B. Exert no force. The decrease in ventilation caused by morphine and by some of the related opioids depends chiefly upon a decrease in A. Blood PC02 concentration. B. Medullary endorphin activity. C. Sensitivity of the medullary respiratory center to carbon dioxide. D. Sensitivity of aortic and carotid chemoreceptors to blood oxygen concentration. - ANSWER-C. Sensitivity of the medullary respiratory center to carbon dioxide. The depth of the clinical gingival sulcus is the distance from the gingival margin to the A. Cementoenamel junction. B. Most apical penetration of the periodontal probe. C. Most apical extension of the junctional epithelium. D. Bottom of the sulcus in well-preserved histologic block sections. - ANSWER-B. Most apical penetration of the periodontal probe. A bevel is CONTRAINDICATED on the cavosurface angles of a Class I dental amalgam cavity preparation. Which of the following best explains why? A. This type of margin is prone to microleakage. B. The cavosurface bevel makes burnishing more difficult. C. A thin flange of the amalgam restorative material might fracture. D. As the tooth undergoes natural attrition, the amalgam margin can abrade. - ANSWER-C. A thin flange of the amalgam restorative material might fracture. Which of the following represents a dental program in which eligible patients receive services at specified facilities from a limited number of dentists? A. An open-panel B. A closed-panel C. A capitation group D. A prepaid group - ANSWER-B. A closed-panel Additional space for successive eruption of permanent maxillary molars is provided by A. Interstitial bone growth. B. Appositional growth at the maxillary tuberosity. C. Continuous expansion of the dental arch due to sutural growth. D. An increase in palatal vault height due to alveolar growth. - ANSWER-B. Appositional growth at the maxillary tuberosity. Which of the following responses made by the dentist is the MOST likely to increase a patient's adherence to oral hygiene prescriptions? A. You don't want lots of cavities, do you? B. If you take my advice, you can save yourself pain and money. C. You really should spend the time it takes to brush and floss. D. What do you see as some of the problems with this approach? E. I can assure you that this approach is quick and easy. - ANSWER-D. What do you see as some of the problems with this approach? Amalgam scrap should be stored in a tightly-sealed container and covered with which of the following? A. Water B. Glycerin C. Sulfide solution D. Sodium hypochlorite solution - ANSWER-C. Sulfide solution The soft tissue-tooth interface that forms most frequently after flap surgery in an area previously denuded by inflammatory disease is a A. Collagen adhesion. B. Reattachment by scar. C. Long junctional epithelium. D. Connective tissue attachment. - ANSWER-C. Long junctional epithelium. Which of the following is inherited as an autosomal dominant trait? A. Lichen planus B. Bullous pemphigoid C. Pemphigus vulgaris D. White sponge nevus E. Epidermolysis bullosa acquisita - ANSWER-D. White sponge nevus Which of the following is the primary substance or material removed during root planing? A. Stain B. Dentin C. Plaque D. Calculus E. Cementum - ANSWER-E. Cementum Three days after full mouth extraction, an elderly patient complains of black-and-blue marks on her neck. The most probable diagnosis is A. Thrombocytopenia. B. Capillary fragility. C. Hematoma formation. D. Postoperative ecchymosis. - ANSWER-D. Postoperative ecchymosis. Most epidemiologic studies indicate that gingivitis in children is relatively common. A strong positive association between specific nutritional deficiencies and the presence of periodontal disease in children and adults has been demonstrated. A. Both statements are TRUE. B. Both statements are FALSE. C. The first statement is TRUE, the second is FALSE. D. The first statement is FALSE, the second is TRUE. - ANSWER-C. The first statement is TRUE, the second is FALSE. Chroma is that aspect of color that signifies the A. Degree of grayness. B. Degree of translucency. C. Degree of saturation of the hue. D. Combined effect of the hue and value. - ANSWER-C. Degree of saturation of the hue. In a state of gingival health, the narrowest width of keratinized gingival tissue is usually found on the facial aspect of which of the following teeth? A. Mandibular central incisors B. Mandibular first premolars C. Maxillary second premolars - ANSWER-B. Mandibular first premolars A patient is experiencing a throbbing pain in a specific tooth. This pain is aggravated by heat and relieved by cold. The tooth is sensitive to percussion. The most likely diagnosis is A. Occlusal trauma. B. Periodontal abscess. C. Irreversible pulpitis. D. Hyperemia of the pulp. - ANSWER-C. Irreversible pulpitis. Which of the following is the most consistent finding in systemic infections? A. Fever B. Tachypnea C. Lymphadenopathy D. Abscess formation E. Cellulitis formation - ANSWER-A. Fever Which of the following represents the variability about the mean-value of a group of observations? A. Sensitivity B. Standard deviation C. t-Statistic D. Specificity - ANSWER-B. Standard deviation Which of the following characterize(s) the histopathologic changes in chronic gingivitis? A. The loss of rete pegs and the dissolution of the basement membrane B. An inflammatory infiltrate in which macrophages predominate C. An inflammatory infiltrate in which neutrophilic leukocytes and mast cells predominate D. The destruction of the principal fibers of the periodontal ligament E. The disruption of the gingival fibers and an inflammatory infiltrate of plasma cells, lymphocytes, and neutrophilic leukocytes - ANSWER-E. The disruption of the gingival fibers and an inflammatory infiltrate of plasma cells, lymphocytes, and neutrophilic leukocytes When providing endodontic treatment for a patient who has a history of rheumatic heart disease, the dentist should especially avoid which of the following? A. Underinstrumentation of a vital tooth B. Overinstrumentation of a vital tooth C. Underinstrumentation of a necrotic tooth D. Overinstrumentation of a necrotic tooth - ANSWER-D. Overinstrumentation of a necrotic tooth Which of the following tissues is MOST sensitive to radiation-induced carcinogenesis? A. Liver B. Thyroid C. Salivary gland D. Prostate - ANSWER-B. Thyroid Which of the following most strongly suggest cause-and-effect relationships? A. Correlational studies B. Controlled clinical trials C. Case reports D. Epidemiologic surveys - ANSWER-B. Controlled clinical trials Spontaneous osteogenic sarcoma is associated with which of the following disease processes of bone? A. Paget's disease B. Histiocytosis-X C. Hyperparathyroidism D. Letterer-Siwe disease E. Osteogenesis imperfecta - ANSWER-A. Paget's disease The drug-of-choice for the treatment of adrenergically-induced arrhythmias is A. Quinidine. B. Lidocaine. C. Phenytoin. D. Propranolol. - ANSWER-D. Propranolol. Which of the following drugs, when administered intravenously, is LEAST likely to produce respiratory depression? A. Fentanyl B. Diazepam C. Thiopental D. Meperidine E. Pentobarbital - ANSWER-B. Diazepam Which of the following safety techniques provides the GREATEST DECREASE in overall radiation-risk to patients? A. Changing from Group D to Group E film B. Switching from round to rectangular collimation C. Using an automatic rather than manual processing switch D. Adding a cervical collar to a leaded apron - ANSWER-B. Switching from round to rectangular collimation Premature exfoliation of a primary mandibular canine is most often the sequela of which of the following? A. Caries B. Trauma C. Serial tooth extraction D. Arch length inadequacy - ANSWER-D. Arch length inadequacy In lateral movements, the non-working condyle moves in what direction? A. Laterally, posteriorly, and superiorly B. Superiorly, posteriorly, and inferiorly C. Inferiorly, anteriorly, and medially D. Inferiorly, anteriorly, and laterally - ANSWER-C. Inferiorly, anteriorly, and medially A dentist who is planning to restore a tooth with gold alloy desires a certain amount of expansion in the casting investment mold. Which of the following best explains why this expansion is desirable? A. It allows for the shrinkage of the molten metal and the wax pattern. B. It compensates for the shrinkage of the molten metal as it cools in the mold. C. It makes the metal casting larger than the wax pattern so that the casting will fit the tooth tightly. - ANSWER-B. It compensates for the shrinkage of the molten metal as it cools in the mold. The dentist is using polyether material to make impressions. The physical property of this material that should concern this dentist is the A. Coefficient of thermal conductivity. B. Hydrophilic nature. C. Extended setting time. D. High modulus of elasticity. - ANSWER-D. High modulus of elasticity. Streptococcus mutans is considered to be a principal etiologic agent of caries because it produces organic acids and it A. Forms a gelatinous matrix. B. Metabolizes substrate from saliva. C. Derives energy from enamel constituents. E. Lives symbiotically with Lactobacillus acidophilus. - ANSWER-A. Forms a gelatinous matrix. Which of the following best explains how high-copper amalgam restorations differ from conventional amalgam restorations? The high-copper restorations A. Have little or no tin-mercury phase. B. Require less mercury, so there is more matrix formed. C. Corrode at an accelerated rate due to increased copper content. D. Are unaffected by moisture contamination in the presence of zinc. - ANSWER-A. Have little or no tin-mercury phase. What do Gardner syndrome and cleidocranial dysplasia have in common? A. Intestinal polyps B. Intraoral pigmentation C. Impacted supernumerary teeth D. Osteomas of the skull and jaws - ANSWER-C. Impacted supernumerary teeth A healthy 3-year-old child has just had a routine extraction of a primary mandibular molar. Which of the following postoperative problems is the most likely to occur? A. Prolonged bleeding B. Pain C. A dry socket D. Lip bite - ANSWER-D. Lip bite Two hours elapsed before a patient with an avulsed tooth was able to see a dentist. The dentist replanted and splinted the tooth, and performed nonsurgical endodontic therapy. Which of the following probably resulted after the treatment? A. Radicular cyst formation B. Condensing osteitis C. External root resorption E. Chronic periapical periodontitis - ANSWER-C. External root resorption A practitioner who is restoring a tooth with composites wishes to be sure that the matrix has adhered to the filler. Which of the following agents adheres the resin matrix to the filler? A. Wetting B. Coupling C. Catalyzing D. Activating - ANSWER-B. Coupling An operator has chosen to use a shielded open-ended cone. Which of the following will contribute the most to patient gonadal dose?