/80 0 Oral Microbiology Preparation (Dr. Chhay Sokdalis) 1 / 80 1) Which of the following statements on streptococci are not true? a. Can cause caries in the absence of sucrose b. Can be primarily differentiated by their hemolytic reactions on blood agar c. Some are Gram-positive and anaerobic d. mutans group streptococci cause caries 2 / 80 2) Which of the following statements on dentoalveolar infections is INEXACTE? a. Endogenous oral commensals, usually from apex of a necrotic tooth b. Prevalence and severity increase with age c. Clinical presentation depends on virulence of causative microorganisms. d. Pus-producing infections associated with teeth and surrounding supporting structures 3 / 80 3) What are the predominant plaque bacteria in healthy condition? a. Anaerobic cocci (-) and rods (-). b. Anaerobic cocci (+) and rods (+) c. Facultative anaerobia cocci (+) and rods (+) d. Facultative anaerobia cocci (-) and rods (-) 4 / 80 4) Mouthwashes contain several chemical agents to effectively control oral malodor. Select the agent that does not belong in mouthwashes:? a. Chlorhexidine gluconate b. essential oils c. Cetylpyridinium. d. alcohol 5 / 80 5) Which of the following statements on dental caries is INEXACTE? a. Commonly associated with malnutrition and possibly systemic diseases b. Destruction of tissues of tooth by bacterial fermentation of dietary carbohydrates. c. Carious lesion is result of demineralization of enamel d. Chronic endogenous infection caused by normal oral commensal flora 6 / 80 6) The bacteria detected in localized aggressive periodontitis are:? a. Treponema denticola and fusobacterium nucleatum. b. A. actinomycetemcomitans, Capnocytophaga spp. and Porphyromonas gingivalis. c. Fusiformis and Tanerella forsythus. d. Borrelia vincenti and medium size spirochetes. 7 / 80 7) Which of the following vaccines would you recommend to your new female dental surgery assistant starting work with you? a. Measles–mumps–rubella (MMR) b. Hepatitis B immunoglobulin c. Hepatitis A d. Hepatitis C. 8 / 80 8) Normal flora help protect the body from pathogens … ? a. by secreting histamines. b. by attacking pathogenic bacteria c. by sharing plasmids with pathogenic bacteria d. by competing with other bacteria 9 / 80 9) Which of the following statements on acute necrotizing ulcerative gingivitis is INEXACTE? a. Commonly associated with poor and neglected oral hygiene b. If untreated, ulcers enlarge and spread to involve marginal c. The disease may be inherited (autosomal recessive). d. Possibly systemic diseases 10 / 80 10) The human body provides a favorable habitat for microorganisms. Which of the following does not contribute to this favorable habitat? a. Low levels of moisture b. Stable temperature c. Relatively stable pH. d. Constant source of nourishment 11 / 80 11) Probiotics exhibit all BUT the following characteristics:? a. Remain viable for a long time b. Nontoxic and nonpathogenic to host c. Have beneficial effect on host. d. Mimic antibiotics 12 / 80 12) Which of the following bacteria that is predominant in chronic periodontitis? a. Prevotella intermedia. b. Streptococcus sanguinis c. Actinomyces viscsus d. Porphyromonas gingivalis 13 / 80 13) Microorganisms play the most essential role.? a. Streptococcus bovis b. Streptococcus anginosus. c. Dental caries is associated with: d. Streptococcus mutans e. Streptococcus agalactiae 14 / 80 14) Aggressive periodontitis is treated by:? a. Tetracycline 250 mg 3 times/day for 4 weeks b. Amoxicillin 500 mg 3 times/day for 2 weeks. c. Metronidazole 250 mg 3 times/day for 1 weeks d. Penicillin 500 mg 3 times/day for 3 weeks 15 / 80 15) Communicable diseases can spread by several methods. Which is not an example of the direct transmission mode of disease spread? a. Placental transfer. b. Transfusion c. Sexual intercourse d. Contact with contaminated food 16 / 80 16) An abortive infection is one in which: ? a. Cell multiplication is stopped. b. Transplacental infection of the fetus occurs c. Progeny virus is not produced d. The infected cells are killed 17 / 80 17) An example of a nonspecific chemical barrier to infection is…? a. cytotoxic T cells. b. cilia in the respiratory tract c. unbroken skin d. lysozyme in saliva 18 / 80 18) Which of the following statements on periodontal disease is INEXACT? a. Manage by restoration b. Disorders of supporting structures of teeth c. Can be controlled by using mechanical cleansing techniques. d. One of major diseases afflicting humankind 19 / 80 19) Demineralization of inorganic portion and destruction of organic of tooth is known as:? a. Dental caries b. Dentinal caries c. Enamel caries d. Pulpitis. 20 / 80 20) What are the predominant plaque bacteria in periodontitis? a. Anaerobic rods (-). b. Facultative anaerobia cocci (-) c. Facultative anaerobia cocci (+) d. Anaerobic rods (+) 21 / 80 21) Which of the following is associated with dental caries? a. Staphylococcus aureus. b. Streptococcus pneumonia c. Lactococcus lactis d. Streptococcus mutans 22 / 80 22) Which of the following statements on aggressive periodontitis is EXACTE? a. 95% of all periodontal diseases. b. Most prevalent disease globally c. Initiation is onset of puberty d. Prevalence and severity decrease with age 23 / 80 23) The dietary carbohydrate most likely involved in etiology of dental caries is 😕 a. Dextran b. Polysaccharide c. Xylitol. d. Sucrose 24 / 80 24) The mutans group of streptococci are key cariogenic pathogens. Which of the following belongs to the mutans group? a. Streptococcus mutans b. Streptococcus pneumonia. c. Streptococcus pyogenes d. Streptococcus saprophyticus 25 / 80 25) Which of the following statements on the natural history of periodontal disease is INEXACT? a. Gram-positive cocci predominate in healthy gingival crevice b. facultative anaerobes predominate in gingivitis. c. the proportion of Gram positive rods decreases to nearly 5% in chronic marginal gingivitis d. Gram-negative anaerobes predominate in chronic periodontitis 26 / 80 26) There are many different types of bacteria normally present in the oral cavity. Which of the following is the name of the one most likely to be associated with the onset of dental caries? a. Spirochaetes b. Staphylococcus c. Bacteroides d. Streptococcus. 27 / 80 27) Which of the following statements on chronic periodontitis is INEXACTE? a. Most prevalent disease globally b. 95% of all periodontal diseases. c. Prevalence and severity decrease with age d. Morbidity 70–80% 28 / 80 28) In dentoalveolar abscess, the bacteria reach pulp by:? a. Plaque microorganisms b. Traumatic exposure during dental treatment c. Primary herpetic gingivostomatitis. d. Poor oral hygiene 29 / 80 29) Viruses can be cultivated in? a. Lab media b. Tissue culture c. Broth d. Blood culture. 30 / 80 30) How to manage dentoalveolar abscess? a. Reducing cariogenic flora b. Removing source of infection and prescribing antibiotics c. Probiotics replacement of cariogenic bacteria d. Initial local debridement. 31 / 80 31) Widely accepted theory of dental caries is 😕 a. Acidogenic theory b. Proteolytic theory c. Proteolytic chelation theory d. Autoimmune theory. 32 / 80 32) Which is not true about Ludwig angina? a. Caused by an acute or chronic destructive process in periodontium b. May need emergency tracheostomy c. Maintain fluid balance. d. Involves submandibular space 33 / 80 33) Which of the following statements on diagnosis of dental caries is INEXACTE? a. Laser fluorescence b. Probing c. Electrical impedance d. Organoleptic assessment. 34 / 80 34) What are the predominant plaque bacteria in gingivitis? a. Anaerobic cocci (-) and Facultative anaerobia rods (-). b. Facultative anaerobia cocci (-) and Anaerobic rods (-) c. Anaerobic cocci (+) and Facultative anaerobia cocci rods (+) d. Facultative anaerobia cocci (+) and Anaerobic rods (-) 35 / 80 35) Turbid dentin in carious tooth is all EXCEPT:? a. Zone which cannot be remineralised b. Zone of bacterial invasion c. Zone that need not be removed before restoration. d. Zone in which collagen is irreversibly denatured 36 / 80 36) For a bacterium to be seriously considered in the etiology of dental caries, it must 😕 a. produce intracellular dextrans. b. be lethal for animals c. produce extracellular proteolytic enzyme d. exist regularly in the dental plaque 37 / 80 37) Gram staining reflects in bacteria? a. differences in bacterial metabolism b. differences in the cell wall structure c. differences in the bacterial plasmatic membrane d. presence or absence of nucleus. 38 / 80 38) The most common protozoa in the oral cavity of people ? a. Giardia lamblia. b. Entamoeba histolytica c. Giardia muris d. Trichomonas tenax 39 / 80 39) Following can be used for cultivation of viruses EXCEPT:? a. Primary cell b. Cell cultures c. Diploid cell line d. Blood agar. 40 / 80 40) Members of the genus Lactobacillus are normal microflora of the? a. Hair b. Skin c. Mouth d. Nasopharynx. 41 / 80 41) With regard to prevention of dental caries, which of the following statements are true? a. substituting cariogenic artificial sweeteners b. probiotic therapy with ‘cariogenic’ bacteria is the most promising approach c. water fluoridation, though effective, leads to other major systemic illnesses d. remineralization of early lesions can be accomplished by fluoridated toothpaste. 42 / 80 42) Viruses that persist in the cell and cause recurrent disease are considered? a. resistant. b. cytopathic c. oncogenic d. latent 43 / 80 43) What is the cause of death in Ludwig angina? a. Dysrhythmia b. Asphyxia c. Pneumonia d. Wall rupture. 44 / 80 44) The peak incidence of juvenile periodontitis in children occurs at ages:? a. 10-13 years. b. 5-7 years c. 1-3 years d. Birth-6 months 45 / 80 45) Lysozyme is present in? a. Saliva. b. Cerebro spinal fluid (CSF) c. Urine d. Sweat 46 / 80 46) Virus replicate by which of the following? a. Within a host cell b. Extracellular c. Cell division d. Reproduction. 47 / 80 47) Bacterial pathogens attach most often by all except which of the following mechanisms? a. Adhesins b. Spikes c. Glycocalyx. d. Fimbriae (pili) 48 / 80 48) Mouthwashes used for controlling oral malodor should contain? a. Antibacterial agent b. Xylitol. c. Alcohol d. Sugar to make them more palatable to consumers 49 / 80 49) Which genus of bacterium contributes to plaque, caries, gingivitis, and periodontal disease? a. Bacillus. b. Escherichia c. Staphylococcus d. Streptococcus 50 / 80 50) The primary cause of periodontal diseases is? a. Calculus b. Dental Plaque c. Restoration. d. Malocclusion 51 / 80 51) How to manage dental caries? a. Minimal cavity preparation techniques b. Institute surgical drainage. c. Eliminate primary source of infection d. Initial local debridement with ultrasonic scaling 52 / 80 52) Which of the following statements on prevention of dental caries is INEXACTE? a. Plaque-free by routine oral hygiene measures. b. Increasing cariogenic flora c. Stopping or reducing between-meal consumption of carbohydrates d. Probiotics replacement of cariogenic bacteria 53 / 80 53) Microorganism that can grow in the presence as well as in the absence of molecular oxygen is? a. facultatively anaerobic. b. obligatory anaerobic c. microaerobically d. obligatory aerobic 54 / 80 54) Which of the following bacteria that is predominant in aggressive periodontitis? a. Porphyromonas gingivalis b. Aggregatibacter actinomycetemcomitans c. Prevotella intermedia. d. Streptococcus sanguinis 55 / 80 55) The main difference in true bacteria and mycoplasma is that it does not posses:? a. A capsule. b. ATP synthesis c. Flagella d. Cell wall 56 / 80 56) The organisms which can grow best in the presence of a low concentration of oxygen? a. Aerobic b. Aerophilic c. Anaerobic. d. Microaerophilic 57 / 80 57) Initiation of dental caries depends upon:? a. availability of carbohydrate food b. formation of large amount of acid c. Localisation of acid over tooth surface. d. viscosity of saliva 58 / 80 58) Predisposing factors for acute necrotizing ulcerative gingivitis include INEXACT:? a. severe malnutrition b. immunodeficiency c. diabetes. d. heavy smoking 59 / 80 59) How to manage acute necrotizing ulcerative gingivitis? a. Institute surgical drainage. b. Tetracycline 250 mg 3 times/day for 4 weeks c. Initial local debridement by ultrasonic scaling d. Reducing cariogenic flora 60 / 80 60) Which of the following statements on complication of Ludwig’s angina is INEXACTE? a. Death due to asphyxiation b. pread of infection to masticator c. Airway obstruction due to edema of glottis d. Respiratory tract infections. 61 / 80 61) Which of the following disease most commonly afflicts human? a. Periodontal disease b. Dentoalveolar abscess c. Periodontal abscess. d. Ludwig’s angina 62 / 80 62) Dentoalveolar abscess is treated by:? a. Drainage through the gingival sulcus or by an external incision. b. Gingivoplasty c. Periodontal flap procedure d. Gingivectomy 63 / 80 63) Which of the following procedures can be regarded as optimal for controlling cross infection in a dental clinic? a. Washing the gloves and reusing after visual examination of a patient b. Wearing headgear for all operational procedures c. Wearing a single face mask for 3 h d. Wearing gloves after removal of all hand jewellery. 64 / 80 64) Which of the following statements on clinical sign of dental caries is INEXACTE? a. Roughened and cavitation b. Pseudomembrane (slough) c. White-spot lesion. d. Chalkywhite lesion 65 / 80 65) Caries, all are true except:? a. Smooth surface caries occur due to streptococcus mutans b. Fluorides help in reducing caries incidence. c. Pit and fisssure caries can be prevented by using pit and fissure sealants d. Lactobacillus is the main causative organism in plaque 66 / 80 66) The following infectious agents are likely to be transmitted in dental care settings:? a. Candida albicans b. Hepatitis G c. Streptococcus pyogenes d. Influenza. e. Ph. Heng Kanika 67 / 80 67) Which of the following statements on clinical sign of necrotizing ulcerative gingivitis is INEXACTE? a. Inflamed, red, shiny and bleeding gingivae b. Irregular alveolar bone loss around teeth c. Unpleasant metallic taste d. Loss of supporting tissues (noma). 68 / 80 68) Which of the following statements on dental caries are true? a. recurrent caries is commonly associated with an existing restoration. b. fissure caries is commonly seen in the lingual surface of the incisors c. signs of fissure caries can be first detected in dentine d. approximately 90% of people over 60 years in the West have root surface caries 69 / 80 69) The legend of worms, endogenous theories, chemical theories and parasitic theory are early theories explaining:? a. Periodontitis b. Gingivitis c. Osteomylitis. d. Dental caries 70 / 80 70) Which of the following statements on dentoalveolar abscess is true? a. it is often precipitated by bacteria from the systemic route (anachoresis) b. it is frequently implicated as a cause of brain abscess c. it often resolves without antibiotics after adequate drainage. d. it is a infection of sublingual and submandibular spaces 71 / 80 71) Microorganisms that are frequently implicated in the pathogenesis of periodontal abscess include:? a. Porphyromonas spp. b. Treponema pallidum c. Streptococcus pneumonia d. Staphylococci 72 / 80 72) Chronic periodontitis is characterized by INEXACT:? a. absence of pain in general. b. tooth mobility and migration c. systemic symptoms like fever d. gingival recession 73 / 80 73) Which of the following statements on Ludwig’s angina is INEXACTE? a. little amount of pus is yielded on surgical drainage. b. it may warrant an urgent tracheostomy c. it needs to be treated with high-dose, parenteral metronidazole and penicillin d. the majority of cases are due to submandibular sialadenitis 74 / 80 74) A facultative anaerobic is:? a. Ordinarily an aerobe but can grow in absence of O2. b. Only grow in the presence of O2 c. Ordinarily an anaerobe but can grow with O2 d. Only grow anaerobically 75 / 80 75) Which of the following bacteria that is predominant in healthy condition? a. Actinomyces viscsus b. Streptococcus milleri c. Streptococcus sanguinis d. Actinomyces israelii. 76 / 80 76) Which of the following statements on clinical sign of chronic periodontitis is INEXACTE? a. Inflamed, red, shiny and bleeding gingivae. b. Gross gingival inflammation, fibrosis and some shrinkage c. Irregular alveolar bone loss around teeth d. Tooth mobility and migration 77 / 80 77) Main predisposing factors of acute necrotizing ulcerative gingivitis is:? a. Severe malnutrition b. Host factors c. Intake of fermentable carbohydrates. d. Dental caries 78 / 80 78) The main causative agent of Ludwig angina is:? a. Fusobacteria. b. Streptococcus pneumonia c. Treponema pallidum d. Staphylococci 79 / 80 79) The main causative agent of Ludwig’s angina is:? a. Group A streptococci. b. Porphyromonas c. Legionella infection d. Staphylococci 80 / 80 80) True about caries, all EXCEPT:? a. Chronic endogenous infection b. Not due to microorganisms c. Microorganisms play the most essential role d. Demineralization of enamel. 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