Dental plaque/ Periodontal microbiology

 All the questions have been directly picked from Carranza 11th edition



 1. Pre-requisite for plaque formation is

a. Pellicle                                                                                    B. Glycoprotein

c. Mucopolysaccharide                                                            d. Dextran

Ans:  a. Pellicle

Pellicle formation starts with absorption of glycoprotein form saliva.

 

2. The yellow white, soft sticky, deposit of cellular debris and bacteria loosely adherent on tooth surface is

a. Pellicle

b. Materia alba

c. Plaque

d. Calculus

Ans: b. Materia alba

Sequence of formation is Pellicle-Materia alba-Plaque-Calculus with pellicle formation being the first.

 

3. Inorganic component of subgingival plaque is derived from

a. Saliva                                                                                           b. Crevicular fluid

c. a and b                                                                                       d. Fluids ingested

Ans: b. crevicular fluid

For supragingival plaque, it is from the saliva.

 

4. Composition of plaque formed on all restorative material surfaces is similar except that on

a. Composite

b. Amalgam

c. Silicate.

d None of the above

Ans: c. Silicates

Composition of plaque over silicates changes due to the fluoride releasing capacity of silicates.

 

 

5. Hemin iron from the breakdown of host hemoglobin may be important in metabolism of which of the following

a. Porphyromonas gingivalis                                                        b. Prevotella intermedia

c. Prevotella melanogenicus                                                         d. Wollinella recta

Ans: a. Porphyromonas gingivalis

 

6. According to Glickman, Maximum accumulation of plaque takes place in

a. 7 days                                                                                           b.15 days

c. 30 days                                                                                          d.60days

Ans: c 30days

-Maximum accumulation of plaque takes place approximately in 21 days.

-Acquired pellicle formation takes place within seconds.

-Initial plaque formation within 2 hours

-Irreversible colonisation of bacteria after 2 hours

-supragingival plaque well established within 6 hours

 

7. After cleansing and pumicing the tooth surface, plaque formation takes place within

a. A few minutes                                                                                 b. 1/2 -1 hour

c.2-4-hour                                                                                             d. After 1 hour

Ans: b ½ to 1 hour

The pellicle formation takes place within nanoseconds.

 

 

8.‘’Corncob appearance’’ is seen in

a. supragingival calculus

b. subgingival calculus

c Supragingival plaque

d. Subgingival plaque

Ans; c Supragingival plaque

It is seen in supragingival plaque towards tooth surface.

 

9. Bacterial communication with each other in a biofilm is through a phenomenon known as

a. Coaggregation phenomenon

b. Coadhesion phenomenon

c. Corncob phenomenon

d. Quorum sensing

Ans: d Quorum sensing

 

Bacterial communication takes place with the help

1. Peptides released by gram positive organisms during growth

2. Universal signal molecule known as AI-2(Autoinducer-2)

 

10. Bacterial enzyme capable of causing the breakdown of ground substance of the periodontal ligament

a. Lysozyme                                                                                b. Peroxidase

c. Hyaluronidase                                                                        d. streptokinase

Ans: c hyaluronidase

 

11. Specific plaque hypothesis was put forward by

a. Jenco                                                                                          b. Listgarten

c. Loesche                                                                                        d. Marsh

Ans: c. Loesche

 

12. ‘’Coaggregation’’ is mainly predominated by

a. Interaction between gram positive bacteria

b. Interaction between gram negative bacteria

c. Interaction between gram positive and gram-negative bacteria

d. None

Ans: b. Interaction between gram negative bacteria

Recognition of genetically distinct partner cell types due to interaction of carbohydrate and protein molecule located on the bacterial cell surface and mediated by lectin like adhesins.

 

13. Co-adhesion is a process of

a. Attachment of primary colonizers on the tooth surface

b. Attachment of new bacteria on the bacterial receptors

c. formation of taste tube brush like appearance

d. Irreversible colonization of bacteria on tooth

 

Ans: b Attachment of new bacteria on bacterial receptors

 

14. Following removal, plaque formation is rapid on

a. Interproximal surface                                                        b. Occlusal surface

c. Lingual surface                                                                       d. Same on all surface

Ans: a Interproximal surface

 

15.Which of the tooth has most of the plaque?

a. Gingival third

b. Incisal third

c. Middle third

d. Uniform on all surfaces

Ans: a  Gingival third

Plaque accumulates mostly on gingival third of tooth surfaces due to lack of movement of food during mastication.

16. Who modified the Koch’s postulates as related to periodontal disease?

a. Socransky                                                           

b. Glickman

c. Russel

d. Greene and Vermillion

Ans: a. Socransky

 

17.‘Corncob appearance’ of plaque is seen on

a.1week old plaque

b.2weeks old plaque

c.3weeks old plaque

d.4weeks old plaque

Ans: c 3 weeks old plaque

 

18.Predominat bacteria found in two-days old plaque

a.       Steptococci

b.      Bacteroids

c.       Spirochetes

d.      Actinomyces

Ans: a

 

  19.Corncob appearance of bacteria in plaque is seen towards

a.       Tooth surface

b.      Outer surface

c.       Middle of plaque

d.      All of the above

            Ans: A

 

  20.Supragingival plaque causes

a.       Gingivitis

b.      Periodontitis

c.       Pericoronitis

d.      Apthous ulcers

Ans-A

Subgingival plaque towards the tissue causes periodontits

Subgingival plaque towards the tooth causes root caries.

 

  21. Radius of action of toxins in bacterial plaque is

a. Less than 2.5mm                                                   b. Greater than 3.5mm

c Less than 1.5mm                                                       d.1.5-2.5mm

  Ans. d 1.5-2.5mm

 Radius of action is the range of effectiveness of the bacterial toxins.

 

22. P.intermedium are present in -------- complexes.

a.      Orange

b.      Red

c.       Green

d.      Purple and yellow

   Ans –a

Aggregetibacter (serotype a) falls under green complex

 

  23. All of the following are protective agents in periodontal disease except

a.       S. sanguis

b.      C. ochracea

c.       V. parvula

d.      B. oralis

     Ans-d

 

    24. Which of the following organisms is not implicated in aetiology of periodontal disease

a.       Bacteroides

b.      Wolinella

c.       Neisseria

d.      Eikenella

       Ans-c

     Neiseria is not a periodontal pathogen

 

  25. Which of the following is a periodontal pathogen

a.       S. sanguis

b.      S. mutans

c.       A. viscosus

d.      P. gingivalis

 

Ans-d

 

 

     26. Bacteria which are not found in normal healthy periodontium are

a.       Actinomyces

b.      Capnocytophaga

c.       Veillonella

d.      Eubacterium

       Ans-d

 

   27. Actinobacillus actinomycetemecomitans is

a.       Gram positive aerobe

b.      Gram negative aerobe

c.       Obligate anaerobe

d.      Facultative anaerobe

Ans-d

 

     28. Which micriorganisms has 90% presence in localized aggressive periodontitis?

a.      Spirochaetes

b.      P.gingivalis

c.       P.intermedia

d.      A. actinomycetamcomitans

       Ans-d

 

   29.Localized Aggressive Periodontitis is Present-

a.       Equally in both the sexes

b.      More in males

c.       More in females

d.      More in postmenopausal females

        Ans-c

 

   

30.Breakdown of periodontal fibres in periodontits is due to bacterial enzyme

a.       Collagenase

b.      Hyaluronidase

c.       Coagulase

d.      Streptokinase

      Ans-a

 

 31.Which organism is increased in pregnant ladies

a.      Prevotella intermedia

b.      Porphyomonous gingivalis

c.       Porphyroonas gingivalis

d.      Eichenella corrodens

      Ans-a

 

   32.Leukotoxin is released is released by

a.      P.nucleatum

b.      A.naeslundi

c.       B.forsythna

d.      A.actinomyctemcomitans

     Ans-d

 

  33.BANA test measures activity of

a.       Calculus

b.      Cathepsin

c.       Elastase

d.      Trypsin like enzyme

       Ans-D

    

    34.All of the following organisms can be detected by BANA analysis EXCEPT?

a.      Tanerella forsythia

b.      Porphyomonas gingivalis

c.       Capnocytophaga

d.      Actinomycetemcomitans

         Ans-d

 

 

        35.The carbohydrate not associated with dental plaque is

a.       Dextrose

b.      Levans

c.       Glucose

d.      Rhamnose

        Ans-d

 

      36.Which of the most numerous component of plaque?

a.       Minerals

b.      Food debris

c.       Microorganisms

d.      Leukocytes

         Ans-c

   

       37.Which o the following is the most likely source of collagenase?

a.       Staphylococus aureus

b.      Bacteroides gingivalis

c.       Treponema microdentum

d.      Veillonella alkalescens

         Ans-b

 

       38.Dental plaque is formed by reaction of enzymes on:

a.       Sucrose and lipids

b.      Glucose and proteins

c.       Glucose and lipids

d.      Sucrose and saliva

       Ans-d

 

      39.Subgingival scaling alters the microflora of periodontal pocket

a.       Never gets altered

b.      Aerobes only

c.       Gets altered

d.      Anaerobes only

        Ans-c

 

       40.Lactic acid is produced in mouth by

a)      Saccharolytic  bacteria in supragingival region

b)      Saccharolytic bacteria in subgingival region

c)      Non-saccharolytic bacteria in supragingival region

d)      Non-saccharolytic bacteria in subgingival region

          Ans-a

   

        41.Which of the following bacteria  do not invade host tissue cell?

a)      T. denticola

b)      P. intermedia

c)      P. gingivalis

d)      F. nucleatum

      Ansj-b

   

      42. Which of the following species is found in abundance in adult plaque?

a)      Fusobacterium

b)      Cocci

c)      Bacteroids

d)      All of the above

        Ans-a

 

     43. Periodontitis is caused by

a)      Malnutrition

b)      Supra gingival plaque

c)      Bio-film

d)      Faulty tooth brushing

 

Ans-c

 

     44. The organism least likely to be found in normal gingival crevices is

a)      Fusobacterium sp.

b)      Actinomyces sp.

c)      Diptheroids

d)      Streptococci sps.

         Ans-c

  

       45. Dental plaque adheres to the tooth because:

a)      Levans are gummy

b)      Detrans are insoluble and sticky

c)      Plaque grows into the microorganisms

d)      Microorganisms produce sticky lipoproteins

        Ans-b

    

         46. Co-aggregation is mainly predominated by

a)      Interaction between Gm +ve bacteria

b)      Interaction between Gm -ve  bacteria

c)      Interaction between Gm +ve and Gm –ve bacteria

d)      None of the above

         Ans-b

      

        47. Which of the following species of streptococci is usually not found in human dental plaque

a)      S. mutans

b)      S. sanguis

c)      S. pyogens

d)      S. salivarius

Ans-c

 

48. The biofilms found on tooth surfaces are termed as

a)      Enamel

b)      Dental caries

c)      Dental plaque

d)      Saliva

                Ans-c

 

        49.  Commonly isolated organism from oral cavity is

a)      Streptococcus sanguis

b)      Streptococcus pyogens

c)      Neisseria gonorrhea

d)      Streptpcpccus pneumonia

Ans-a

 

        50.What is/are the method/methods of transferring information in a biofilm?

a)      Quorum Sensing

b)      Conjugation

c)      Plasma transfer

d)      All of the above

       Ans-d

 

51. ‘’Red complex’’ contains organisms that

a. Cause periodontal disease

b. Associated with bleeding on probing

c. Contain early colonisers

d. Contain late colonisers

Ans: b Associated with bleeding on probing

 

53. “Port d’ entrĂ©e” for periodontopathogens

a)      Gingiva

b)      Teeth

c)      Tongue

d)      Periodontal ligament

Ans: B

 

54. After full-mouth extraction, the relative numbers of A. actinomycetemcomitans and P. gingivalis,

a)      Remain unchanged

b)      Is entirely eradicated

c)      Decreased

d)      Increased

Ans: C

 

·         In contrary, the level of S. mutans reach below detectable level after full mouth extraction as they are an obligate periphyte and require hard tissue to colonize.

·         Mucosa cannot act as reservoir for these obligate periphyte.

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