Most commonly submerged tooth is:

 # Most commonly submerged tooth is:

A. Mandibular primary first molar

B. Mandibular primary second molar

C. Maxillary primary first molar

D. Maxillary primary second molar

The correct answer is B. Mandibular primary second molar. 

‘Submerged’ teeth are deciduous teeth, most commonly mandibular second molars, that have undergone a variable degree of root resorption and then have become ankylosed to the bone. This process prevents their exfoliation and subsequent replacement by permanent teeth. After the adjacent permanent teeth have erupted, the ankylosed tooth appears to have submerged below the level of occlusion. This illusion is explained by the fact that there has been continued growth of the alveolar process and also that the crown height of the deciduous tooth is less than that of the adjacent permanent teeth, so that the relative level of occlusion has been changed, not the position of the deciduous tooth. 

The mandibular primary molars are the teeth most often observed to be ankylosed. In unusual cases all the primary molars may become firmly attached to the alveolar bone before their normal exfoliation time. 

Angular osseous defects cannot occur in:

 # Angular osseous defects cannot occur in:

A. Mandibular anterior region

B. Mandibular molar region

C. Maxillary premolar region

D. Maxillary molar region

The correct answer is A. Mandibular anterior region.

Angular osseous defects cannot occur in the mandibular anterior region due to the absence of cancellous bone between the cortical plates.

Which of the following is not a risk indicator for periodontitis?

 # Which of the following is not a risk indicator for periodontitis?

A. HIV/AIDS

B. Bleeding on probing

C. Infrequent dental appointment

D. Osteoporosis

The correct answer is B. Bleeding on probing.

• A risk factor is an environmental, behavioral, or biological factor that, if present directly increases the probability of a disease (or adverse event) occurring and, if absent or removed, reduces that probability.

• A risk indicator is a probable risk factor that has not been confirmed by carefully conducted longitudinal studies. 

• A risk predictor is a characteristic that is associated with an elevated risk for a disease (or adverse event), but may not be part of the causal chain. 

Risk determinants/background characteristics for periodontal disease 

• Genetic Factors 

• Age 

• Gender 

• Socioeconomic status 

• Stress 

Risk indicators for periodontal disease 

• Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome 

• Osteoporosis 

• Infrequent Dental Visits 

Risk markers/predictors for periodontal disease 

• Previous History of Periodontal disease 

• Bleeding on Probing 

Workhorse of periodontal therapy is:

 # Workhorse of periodontal therapy is:

A. Double papilla flap

B. Apically repositioned flap

C. Coronally displaced flap

D. Laterally repositioned flap

The correct answer is B. Apically repositioned flap.

An apically displaced (positioned) flap (APF) is a full-thickness or partial-thickness mucoperiosteal flap. It has a relatively high degree of predictability and is a "workhorse" of periodontal therapy. 

Reversed architecture is most commonly found in:

 # Reversed architecture is most commonly found in:

A. Trauma from occlusion

B. Retrograde periodontitis

C. Aggressive periodontitis

D. ANUP

The correct answer is A. Trauma from occlusion.

Reversed architecture defects are produced by a loss of interdental bone, including the facial plates and the lingual plates, without a concomitant loss of radicular bone, thereby reversing the normal

architecture. Such defects are more common in the maxilla.

Which of the following is not true about beta titanium?

 # Which of the following is not true about beta titanium?

A. Offers less resistance to friction

B. True weldability

C. Biocompatibility

D. High formability

The correct answer is A. Offers less resistance to friction.

- In general, the B-titanium wires have better biocompatibility and high corrosion resistance in the oral environment. The absence of nickel is another important feature and hence can be used in patients with hypersensitivity to nickel. 

- These wires show passivating effect due to the presence of Titanium oxide. Beta-titanium wires can be soldered or welded with ease without losing resiliency. 

- These wires have a high coefficient of friction and are not good for use during retraction mechanics. Hence, their use is restricted to frictionless mechanics like loops and springs. 

- Beta -titanium is a very resilient wire, has high tensile strength, and is easily formable. A continuous arch with T, vertical, helical, and 'L' loops, can be formed in both round wire and rectangular wire.

Which of the following wires cannot be soldered and welded?

 # Which of the following wires cannot be soldered and welded?

A. Beta titanium

B. Optiflex wire

C. Gold wire

D. Stainless steel

The correct answer is B. Optiflex wire.

Optiflex arch-wire is composed of a silicon dioxide core, which provides the force or resiliency to the wire. The silicon resin forms the middle layer. This adds strength to the wire. The nylon outer layer makes the wire stain resistant. 

• Optiflex wire cannot be soldered, or welded, and a sharp bend cannot be placed in the wire. 

• It is a new aesthetic archwire. 

• Highly resilient, and effective for the alignment of crowded teeth. 

Another type of wire which cannot be soldered and welded is NiTi wire.