Multiple Choice Questions Test - I (Basic Periodontology).

This is a self assessment test consisting of ten questions. Click evaluate to get result.

1. The Lamina densa within the epithelial attachment is primarily composed of which collagen fiber type?

The main components of Basement Membrane are laminin, type IV collagen, fibronectin, type VII collagen and proteoglycans. Laminin, the most abundant noncollagenous extracellular matrix protein in BM, has multiple structural and functional roles in tissue development. Type IV collagen provides the basic, strong membrane while fibronectin plays a key role in tissue development and healing through cell matrix binding sites. Anchoring fibrils in the lamina densa, composed mainly of type VII collagen, are known to maintain the integrity of tissues.

Reference: Pierre Le Bars and Assem Soueidan. Distribution Patterns of E-Cadherin, Type VII Collagen and Fibronectin in Denture-Related Stomatitis: A Preliminary Study. The Open Dentistry Journal, 2012, 6, 14-22.

Type I
Type II
Type III
Type IV
Correct Answer - option 4

2. Genes that regulate production of IL-1 are located on,

There are three genes that regulate the production of IL-1: IL1A, IL1B and IL1RN. These genes are located on chromosome 2q13. Genes IL1A and IL1B control the production of the pro-inflammatory proteins, IL-1α and IL-1β, respectively. IL1RN controls the synthesis of an antagonist protein (IL-ra).

Reference: P. S. G. Prakash and D. J. Victor. Interleukin-1b gene polymorphism and its association with chronic periodontitis in South Indian population. International Journal of Genetics and Molecular Biology Vol. 2(8), pp. 179-183, August 2010

Chromosome 1q13.
Chromosome 2q13.
Chromosome 6q13.
Chromosome 21q13.
Correct Answer - option 2

3. Which of the following is not true about Nitric oxide (NO)

NO is generated within biologic tissues via the enzymatic conversion of L-arginine to L-citrulline by nitric oxide synthase (NOS). Nitric oxide synthase (NOS) exists in the body as three distinct isoforms: neuronal (nNOS or NOS-I), inducible (iNOS or NOS-II) and endothelial NOS (eNOS or NOS-III). NO is a short-lived molecule implicated in a wide range of biologics/ processes ranging from immune homeostasis to cancer. While low levels of NO are present in tissue homeostasis, NO is produced at higher concentrations in response to inflammatory stimuli such as bacterial 1,PS via inducible forms of NOS (iNOS). NO is a highly reactive free radical reacting with metal and Oliol residues leading to lipid peroxidation, protein and DNA damages and stimulation of cyrokine release.

Reference: Salvi GE, Lang NP. Host response modulation in the management of periodontal diseases. J Clin Periodontol 2005;32(suppl.6): 108-129.

NO is a short-lived molecule implicated in a wide range of biological processes ranging from immune homeostasis to cancer
NO is generated within biologic tissues via the enzymatic conversion of L-citrulline to L-arginine by nitric oxide synthase (NOS)
Low levels of NO are present in tissue homeostasis, NO is produced at higher concentrations in response to inflammatory stimuli such as bacterial LPS
NO is a highly reactive free radical reacting with metal and thiol residues leading to lipid peroxidation, protein and DNA damages and stimulation of cytokine release
Correct Answer - option 2

4. The ecological plaque hypothesis has been proposed by,

Bacteria have long been recognized as an essential factor in the etiology and progression of periodontal diseases. Toward the end of the 19th century, oral microbiology was just beginning its integration into the study of dentistry, and the work of American microbiologist Willoughby D. Miller played a key role. In the year 1890, Miller published his pioneering book The Microorganisms of the Human Mouth, in which he describes how the accumulation of many different bacterial species collectively induce inflammation and destruction of periodontal tissue. Miller did not believe that any specific organisms were responsible, but that the virulence factors of the community as a whole produced the observed pathology. His hypothesis was backed by the work of J. Leon Williams of London who described dental plaque as a gelatinous accumulation of bacteria, and the obvious association of plaque build-up and periodontal disease. Studies conducted between 1930 to 1970 failed to identify a specific organism as the etiologic agent of periodontal diseases. These negative findings formed a basic tenet of the non-specific hypothesis which suggested that periodontal disease is due to subgingival accumulation of micro-organisms beyond a threshold that can be limited by mechanisms of host resistance (Theilade, 1986). This theory has subsequently evolved into the specific plaque hypothesis, which postulates that certain bacteria are the etiologic agents of distinct forms of periodontal diseases (Loesche, 1976; Tanner et al, 1979; Slots, 1986). Recently an “ecological plaque hypothesis” has been propose that reconciles the key elements of the earlier two hypothesis:
(a) The selection of "pathogenic" bacteria is directly coupled to changes in the environment.
(b) Diseases need not have a specific etiology; any species with relevant traits can contribute to the disease process.

Reference:

Newman , Michael G.. Carranza`s Clinical Periodontology, 11th Edition.

Marsh PD: Are dental diseases examples of ecological catastrophes? Microbiology 2003, 149:279-294.

Walter Loesche.
P.D. Marsh.
Theilade.
Socransky.
Correct Answer - option 2

5. Which one of the following is associated with abnormal collagen formation leading to periodontal disease?

Hypophosphatasia was initially recognized by Rathbun in 1948.  It is an inherited disorder that affects the development of bones and teeth. This condition disrupts a process called mineralization, in which minerals such as calcium and phosphorus are deposited in developing bones and teeth. Hypophosphatasia, as well as Ehlers–Danlos syndrome are associated with abnormal collagen formation and periodontal disease.

Reference: Etienne Mornet. Hypophosphatasia. Orphanet J Rare Dis. 2007; 2: 40.

Papillon–Lefèvre syndrome.
Type 1 diabetes mellitus.
Hypophosphatasia.
Type 2 diabetes mellitus.
Correct Answer - option 3

6. Osteogenic protein-l and 2 (OP-1 and OP-2) also known as,

Bone Morphogenetic protein-7 (BMP-7):

Bone Morphogenetic protein 7 (BMP7), also known as osteogenic protein 1 (OP-1) is a multifunctional growth factor belonging to the transforming growth factor beta (TGF-β) super-family. Initially discovered in 1965 by Marshall Urist, BMPs are the only known proteins capable of inducing the formation of new bone.

Bone Morphogenetic protein-8 (BMP-8):

BMP-8 is also known as osteonegenic protein 2 (OP 2). BMP8 Induces cartilage and bone formation. May be the osteoinductive factor responsible for the phenomenon of epithelial osteogenesis. It also plays a role in calcium regulation and bone homeostasis.

Reference: Michael B. Lee. Bone morphogenetic proteins: background and implications for oral reconstruction. Journal of Clinical Periodontology Volume 24, Issue 6, pages 355–365, June 1997.

BMP-7 and BMP-8, respectively.
BMP-6 and BMP-7, respectively.
BMP-5 and BMP-6, respectively.
BMP-6 and BMP-8, respectively.
Correct Answer - option 1

7. Sub-clinical gingivitis is characterized by,

Initial lesion:

  • Vascular dilation and vasculitis subsequent to the junctional epithelium.
  • Infiltration of polymorphonuclear neutrophils (PMNs) into the junction and sulcular epithelium.
  • Predominant immune cells are PMNs.
  • Perivascular loss of collagen.
  • Alteration of the coronal part of the junctional epithelium.

Early lesion:

  • Vascular proliferation.
  • Rete peg formation and atrophic areas in the SE and JE.
  • Predominant immune cells are lymphocytes (75% of the infiltrate).
  • Increased collagen loss, 70% of collagen destroyed around the cellular infiltrate.

Established lesion:

  • Vascular proliferation and blood stasis.
  • More advanced area of rete-peg formation and atrophic areas in the SE and JE.
  • Predominant immune cells are plasma cells.
  • Continued collagen loss.

Advanced lesion:

The lesion is considered advanced when the destruction of bone is evident.

Vascular proliferation.
Predominantly plasma cells microscopically.
Erythema, bleeding on probing.
Increased crevicular fluid flow and PMN infiltration of sulcular and junctional epithelium.
Correct Answer - option 4

8. Which of the following is not a mechanisms of increased antibiotic resistance of organisms in biofilms

One important mechanism of resistance appears to be the slower rate of growth of bacterial species in biofilms, which makes them less susceptible to many but not all antibiotics. Other mechanisms include exopolymer matrix , extracellular enzymes such as β-lactamases, formaldehyde lyase and formaldehyde dehydrogenase, hydrodynamics and super resistant strains.

Reference: Xu KD, McFeters GA, Stewart PS. Biofilm resitance to antimicrobial agents. Microbiology 2000: 146: 547–549.

Faster rate of growth of bacterial species in biofilms.
Shock proteins and multi-drug efflux pumps.
Exopolymer matrix of a biofilm.
Homeostatic function within the matrix.
Correct Answer - option 1

9. The majority of the proteolytic activity of P. Gingivalis is due to gingipains, which are Cysteine proteinases.

Gingipains are cysteine proteinases produced by P. Gingivalis which are responsible for about 85% of the general proteolytic activity generated by this bacterium. These enzymes are encoded by three genes (rgpA, rgpB, and kgp). In most P. gingivalis strains the gingipains are associated with the bacterial cell surface. Whereas RgpA and Kgp occur in a form of noncovalent complexes of unique catalytic domains with practically identical hemagglutinin/adhesion domains, RgpB is a single-chain enzyme.

Reference: Katarzyna Popadiak, Jan Potempa, Kristian Riesbeck and Anna M. Blom. Biphasic Effect of Gingipains from Porphyromonas gingivalis on the Human Complement System. J Immunol 2007; 178:7242-7250.

Both the statements are true.
Both the statements are false.
Only first statement is true.
P. Gingivalis does not possess proteolytic activity.
Correct Answer - option 1

10. Transfer of genetic sequence within a genome is facilitated by,

Insertion sequences (IS) are defined as mobile genetic elements that are known to encode only functions involved in insertion events. This is to be contrasted with transposons (Tn) that are mobile genetic elements containing additional detectable genes in addition and unrelated to insertion functions (for example, drug resistance). They constitute an important component of most bacterial genomes.  Majority of Insertion sequence elements are between 0.7 and l.8 kb in size and the terminal end is l0 to 40 base pairs in length with perfect or nearly perfect repeats.

Reference:  Jacques Mahillon and Michael Chandler I. Insertion Sequences. Microbiol. Mol. Biol. Rev. 1998, 62(3):725.

Conjugative plasmids.
Conjugative transposones.
Bacteriophages.
Insertion sequences.
Correct Answer - option 4

11. Which of the following is not true about host response in diabetes,

In diabetic patients the function of cells involved in host  response, including neutrophils, monocytes and macrophages is altered. The adherence, chemotaxis and phagocytosis of neutrophils often are impaired. Macrophages and monocytes often exhibit elevated production of proinflammatory cytokines and mediators such as tumor necrosis factor α (TNF-α) in response to periodontal pathogens, which may increase host tissue destruction. Collagen produced by fibroblasts is susceptible to rapid degradation by matrix metalloproteinase enzymes, the production of which is elevated in diabetes. The accumulation of AGEs in patients with diabetes also increases the intensity of the immunoinflammatory response to periodontal pathogens, because inflammatory cells such as monocytes and macrophages have receptors for AGEs. Interactions between AGEs and their receptors on inflammatory cells result in the increased production of proinflammatory cytokines such as IL-1β and TNF-α.

Reference:

Brian L. Mealey. Periodontal disease and diabetes: A two-way street. The Journal of the American Dental Association October 2006 vol. 137 no. suppl 2 26S-31S

Neutrophils, monocytes and macrophages response is altered in diabetic patients
Macrophages and monocytes often exhibit elevated production of proinflammatory cytokines such TNF-α
Fibroblasts do not function properly in high-glucose environments.
Interactions between AGEs and their receptors on inflammatory cells result in the decreased production of proinflammatory cytokines such as IL-1β and TNF-α.
Correct Answer - option 4

12. P. intermedia is increased in pregnancy associated gingivitis because

Kornman & Loesch (1980) have reported that the subgingival flora changes to a more anaerobic flora as pregnancy progresses. Microbilogical investigations show that the only microorganism that increases significantly during pregnancy is Prevotella intermedia and this increase is associated with elevations of levels of systemic estradiol and progesterone. These hormones are used as growth factors by these organisms as a substitute for vit. K.

Reference:

Kornman KS, Loesch WJ. The subgingival microbial flora during pregnancy. J Perio dont Res 1980;15:111.

Kormman S, Loesce J. Effects of estradiol and progesterone on Bacteroides melaninogenicus and Bacteroides gingivalis. Infect Immun 1982; 35: 256-63.

Decreased immunity during pregnancy
Decrease in the number of other putative organisms due to which there is relative increase in number of P. Intermedia.
Elevated levels of estradiol and progesterone cause decreased immune response in body.
Estradiol and progesterone are used as growth factors by P intermedia as a substitute for Vit. K
Correct Answer - option 4

13. Hemorrhagic crusting of his lips following a course of antibiotic therapy in a 55 years old patient having no systemic manifestations is associated with

Erythema multiforme (EM) is an acute, self-limited, and sometimes recurring skin condition that is considered to be a type IV hypersensitivity reaction associated with certain infections, medications, and other various triggers.

Symptoms include:

  • Fever
  • Itching of the skin
  • Joint aches
  • Multiple skin lesions that:

Usually appear as a nodule, papule, or macule and may look like hives

Have a central sore surrounded by pale red rings, also called a "target", "iris", or "bulls-eye"

May have vesicles and blisters of various sizes (bullae)

Are located on the upper body, legs, arms, palms, hands, or feet

May involve the face or lips

 Are usually even on both sides (symmetrical)

Erythema multiforme
Bechet’s syndrome
Systemic lupus erytheromatosis
Pemphigus vulgaris
Correct Answer - option 1

14. Which one of the following is the least likely indication for antibiotic prophylaxis to prevent bacterial endocarditis

Cardiac conditions associated with endocarditis 

Endocarditis prophylaxis recommended:

High-risk category

  • Prosthetic cardiac valves, including bioprosthetic and homograft valves
  • Previous bacterial endocarditis
  • Complex cyanotic congenital heart disease (e.g., single ventricle states, transposition of the great arteries, tetralogy of Fallot)
  • Surgically constructed systemic pulmonary shunts or conduits

Moderate-risk category

  • Most other congenital cardiac malformations (other than above and below)
  • Acquired valvular dysfunction (e.g., rheumatic heart disease)
  • Hypertrophic cardiomyopathy
  • Mitral valve prolapse with valvular regurgitation and/or thickened leaflets

Endocarditis prophylaxis not recommended:

  • Isolated secundum atrial septal defect
  • Surgical repair of atrial septal defect, ventricular septal defect, or patent ductus arteriosus (without residua beyond 6 mos)
  • Previous coronary artery bypass graft surgery
  • Mitral valve prolapse without valvular regurgitation
  • Physiologic, functional, or innocent heart murmurs
  • Previous Kawasaki disease without valvular dysfunction
  • Previous rheumatic fever without valvular dysfunction
  • Cardiac pacemakers (intravascular and epicardial) and implanted defibrillators.

Reference:

Dajani AS, Taubert KA, Wilson W, Bolger AF,Bayer A, Ferrieri P, Gewitz MH, Shulman ST, Nouri S, Newburger JW, Hutto C, Pallasch TJ, Gage TW, Levison ME, Peter G, Zuccaro G : Prevention of bacterial endocarditis. Recommendations by the American Heart Association. JAMA 277 : 1794-1801, 1997.

Previous coronary artery bypass graft surgery
Previous history of endocarditis
Rheumatic fever
Valvular heart disease
Correct Answer - option 1

15. Which of the following hormones is not involved in the minute-to-minute regulation of carbohydrate metabolism?

Blood glucose levels must be held in the range of 4-5 mmoles/l between meals and under 10 mmoles/l after meals.   This kind of management requires hormonal regulation of many processes.  The main actors here are insulin, glucagon, adrenaline and growth hormone.  The "stress" hormones adrenalin, noradrenalin and growth hormone activate lipolysis through a common mechanism.

Insulin
Glucagon
Catecholamines
Growth hormone
Correct Answer - option 4



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