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The principal component of dental plaque is:

 # The principal component of dental plaque is:
A. Dextrans
B. Lactic acid
C. Materia alba
D. Microorganism



The correct answer is D. Microorganism.

Dental plaque is composed primarily of microorganisms. One gram of plaque (wet weight) contains approximately 100000000000 bacteria. The number of bacteria in supragingival plaque on a single tooth surface can exceed 1000000000 cells. In a periodontal pocket, counts can range from 1000 bacteria in a healthy crevice to more than 100000000 bacteria in a deep pocket. With the use of highly sensitive molecular techniques for microbial identification, it has been estimated that more than 500 distinct microbial phylotypes can be present as natural inhabitants of dental plaque.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no:  141


Scaling and root planing:

# Scaling and root planing:
 A. Prevent further loss of attachment in deep pockets
B. Most effective in reducing pocket depth than surgical means
C. More successful in posterior than anterior tooth
D. Same as curettage

 

The correct answer is A. Prevent further loss of attachment in deep pockets.

Of all clinical dental procedures, subgingival scaling and root planing in deep pockets are the most difficult and exacting skills to master. It has been argued that such proficiency in instrumentation cannot be attained, and therefore periodontal surgery is necessary to gain access to root surfaces. Others have argued that although proficiency is possible, it need not be developed because access to the roots can be gained more easily with surgery. However, without mastering subgingival scaling and root-planing skills, the clinician will be severely hampered and unable to treat adequately those patients for whom surgery is contraindicated.

Scaling and root planing alone are effective for reducing pocket depths, gaining increases in periodontal attachment levels, and decreasing inflammation levels (i.e., bleeding with probing). When scaling and root planing are combined with the subgingival placement of sustained-release vehicles, however, additional clinical benefits are possible, including the further reduction of pocket depths, additional gains in clinical attachment levels (e.g., 0.39 mm with minocycline gel), and further decreases in inflammation. Improvements in clinical attachment levels also occur with the chlorhexidine chip (0.16 mm) and doxycycline gel (0.34 mm). When systemic antibiotics are used as adjuncts to scaling and root
planing, the evidence indicates that some systemic antibiotics (e.g., metronidazole, tetracycline) provide additional improvements in attachment levels (0.35 mm for metronidazole; 0.40 mm for tetracycline)
when used as adjuncts to scaling and root planing. The use of anti-infective chemotherapeutic treatment adjuncts does not result in significant patient-centered adverse effects.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 524

When the flaps are not in close apposition, following suturing technique is used:

 # When the flaps are not in close apposition, following suturing technique is used:
A. Direct or loop suture
B. Sling ligation
C. Anchor suture
D. Figure of 8 suture


The correct answer is D. Figure of 8 suture.

Interdental Ligation. Two types of interdental ligation can be used: the direct loop suture and the figure-eight suture. With the figure-eight suture, thread is placed between the two flaps. This suture is used when the flaps are not in close apposition as a result of apical flap position or nonscalloped incisions. This is simpler to perform than the direct ligation. The direct suture allows for a better closure of the interdental papilla. It should be performed when bone grafts are used or when close apposition of the scalloped incision is required.

Reference: Carranza's Clinical Periodontology, 12th Edition, Page no: 586 e1

All the following cements possess anticariogenic properties, EXCEPT:

 # All the following cements  possess anticariogenic properties, EXCEPT:
A. Silicate
B. Glass ionomer
C. Silicophosphate
D. Zinc oxide eugenol



The correct answer is D. Zinc oxide eugenol.

Anticariogenic property of cements makes the enamel (fluorapatite) resistant to acid mediated decalcification. Silica-phosphate has the highest fluoride content followed by silicate and GIC. Polycarboxylate has least fluoride content. They release fluoride throughout the life of restoration but rate of release decreases over time.

Tarnish generally occurs in the oral cavity due to:

 # Tarnish generally occurs in the oral cavity due to:
A. Formation of hard and soft deposits
B. Pigment producing bacteria
C. Formation of their oxides, sulphides or chlorides
D. All of the above



The correct answer is D. All of the above.

Tarnish: It is the surface discoloration or alteration of the surface finish or luster. It generally occurs due to formation calculus, plaque on the surface of the metal. It also occurs due to formation of oxides, sulfides or chlorides. Tarnish is the forerunner of corrosion.

Which of the following alloys exhibit superelasticity and shape memory

 # Which of the following alloys exhibit superelasticity and shape memory?
A. Nitinol
B. Beta titanium
C. Optiflex
D. Stainless steel



The correct answer is A. Nitinol.

The nickel-titanium alloys used in dentistry are based upon the equiatomic intermetallic compound NiTi, which contains 55% nickel and 45% titanium by weight. Orthodontic wire alloys contain small amounts of other elements, such as cobalt, copper, and chromium.

The alloy name “Nitinol” originally came from the two elements nickel (Ni) and titanium (Ti) and the Naval Ordnance Laboratory (NOL) where these alloys were developed. Superelasticity and shape memory are the properties exhibited by Nitinol.



Which die material has a hazardous (lethal) potential during fabrication?

 # Which die material has a hazardous (lethal) potential during fabrication?
A. Improved stone
B. Silver amalgam
C. Electrodeposited silver
D. Epoxy resin



The correct answer is C. Electrodeposited silver.

• Has a lethal potential due to the Electro usage of silver cyanide plated silver 
• Polysulphide impressions can be easily electro plated

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