The contour of the incisal edges of the maxillary anterior teeth relative to the curvature of the lower lip during a social smile is called:

# The contour of the incisal edges of the maxillary anterior teeth relative to the curvature of the lower lip during a social smile is called:

Line of occlusion

b. Curve of Spee

c. Curve of Monson

d. Smile arc

The correct answer is D. Smile arc.

The smile arc is defined as the contour of the incisal edges of the maxillary anterior teeth relative to the curvature of the lower lip during a social smile. For best appearance, the contour of the incisal edges of these teeth should parallel the curvature of the lower lip. If the lip and dental contours match, they are said to be consonant.

A flattened (non-consonant) smile arc can pose either or both of two problems: It is less attractive, and it tends to make you look older (because older individuals often have wear of the incisors that tends to flatten the arc of the teeth). The characteristics of the smile arc must be monitored during orthodontic treatment because it is surprisingly easy to flatten it in the pursuit of other treatment objectives. The data indicate that the most important factor in smile esthetics, the only one that can change the rating of a smile from acceptable to unesthetic, is the smile arc.

Ref: Contemporary Orthodontics, William R. Proffit, 6th Edition.

# Concept of cortical anchorage given by:

# Concept of cortical anchorage given by:

a. Angle 

b. Kingsley 

c. Ricketts 

d. Newton 

The correct answer is C. Ricketts. 

Rickets technique by intentionally bringing the buccal roots of the anchor teeth into contact with the cortical plates of bone thus increasing the anchorage value of such teeth. It should be appreciated that this process should be carried out with great care and precision since overzealous torque can produce root resorption or in extreme cases cortical perforation. (Brezniak& Wasserstein, 2008)

One of the following procedures falls under high bacteremia risk for infective endocarditis:

 

# One of the following procedures falls under high bacteremia risk for infective endocarditis: 

a. Post-operative suture removal 

b. Intraligamentary and intra-osseous local anesthetics injections 

c. Intracanal endodontic treatment 

d. Placement/ removal of removable orthodontic appliances 

The correct answer is B. Intraligamentary and intra-osseous local anesthetics injections.

All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa are the procedures for which endocarditis prophylaxis is reasonable.

The following procedures and events do not need prophylaxis: 

• routine anesthetic injections through noninfected tissue,  
• taking dental radiographs, 
• placement of removable prosthodontic or orthodontic appliances, 
• adjustment of orthodontic appliances, 
• placement of orthodontic brackets, 
• shedding of deciduous teeth, 
• and bleeding from trauma to the lips or oral mucosa. 

Fenestration as an adverse effect of Fixed Orthodontic Treatment

 Fenestration is a notable adverse effect associated with fixed orthodontic treatment. It refers to the formation of a window-like defect in the alveolar bone, where the root of a tooth becomes partially exposed due to the bone's resorption. This condition can occur when excessive or improperly directed orthodontic forces are applied, causing the tooth to move outside the limits of the alveolar bone housing.

The main factors contributing to fenestration include:

Excessive Force Application: Applying too much force during orthodontic treatment can lead to undue stress on the bone, resulting in resorption and fenestration.

Unfavorable Tooth Movement: Moving teeth in directions that extend beyond the anatomical boundaries of the alveolar bone can cause this adverse effect.

Pre-existing Bone Deficits: Patients with naturally thin or compromised alveolar bone are more susceptible to fenestration when undergoing orthodontic treatment.

Fenestration above left maxillary canine in a female patient undergoing fixed orthodontic treatment

The clinical implications of fenestration include increased risk of periodontal problems, potential tooth sensitivity, and aesthetic concerns. Early detection and careful planning of orthodontic forces are crucial to minimize the risk of fenestration. Regular monitoring through clinical and radiographic evaluations can help in identifying early signs of this adverse effect, allowing for timely intervention to prevent further complications.

Detecting fenestration clinically involves a combination of visual examination, palpation, and radiographic assessment. Here are the primary methods used:

1. Visual Examination

Gingival Recession: Look for areas where the gum line appears lower than usual, which may indicate underlying bone loss.

Tooth Root Visibility: In severe cases, the root of the tooth might be visible through the gum tissue.

2. Palpation

Probing: Gently probing the gum tissue around the suspected area can help identify soft spots or depressions that suggest bone loss.

Tactile Sensation: Feeling for irregularities in the bone contour by gently pressing the gingiva around the suspected area.

3. Radiographic Assessment

Intraoral Periapical Radiographs: These provide detailed images of the tooth and surrounding bone, which can help identify areas of bone loss.

Cone Beam Computed Tomography (CBCT): Offers a three-dimensional view of the alveolar bone, making it easier to detect fenestration accurately.

Panoramic Radiographs: These can be used for a broader view, though they are less detailed compared to periapical radiographs and CBCT.

4. Additional Diagnostic Tools

Periodontal Probing Depths: Increased probing depths around a tooth can indicate bone loss.

Bone Scanning: In some cases, advanced imaging techniques like bone scans might be used for a more detailed assessment.

Clinical Signs to Watch For

Localized Inflammation: Swelling or redness around the affected area.

Pain or Discomfort: Patients may report unusual sensitivity or pain in the area, especially when pressure is applied.

Changes in Tooth Position: Shifts in tooth alignment may also indicate underlying bone issues.

Regular follow-up appointments and careful monitoring are essential for early detection and management of fenestration during orthodontic treatment.

The daily requirement of vitamin B12 is:

 # The daily requirement of vitamin B12 is: 

A. 0.25-0.67 mcg per day

B. 3-5 mcg per day

C. 0.5-0.7 mcg per day

D. 1-2 mcg per day

The correct answer is D. 1-2 mcg per day.

Vitamin B12 plays a crucial role in maintaining healthy nerve function, supporting red blood cell production, and aiding in DNA synthesis. This range is in line with the daily recommended intake for vitamin B12 for most adults, which is typically around 2.4 mcg per day according to various health guidelines.

Organism most commonly seen in lung abscesses is:

 # Organism most commonly seen in lung abscesses is: 

A. Candida albicans 

B. Herpes zoster virus 

C. Oropharyngeal flora 

D. Staphylococcus aureus

(PSC KOSHI 2081)

The correct answer is C. Oropharyngeal flora. 

Lung abscesses are typically caused by aspiration of bacteria from the oropharyngeal flora. This flora includes a mix of aerobic and anaerobic bacteria normally found in the mouth and throat. When these bacteria are aspirated into the lungs, they can cause an infection leading to a lung abscess.

While the other options listed can cause infections in the lungs, they are not the most common cause of lung abscesses:

Candida albicans (A): This fungus is a common cause of opportunistic infections, but it is not the most common cause of lung abscesses.

Herpes zoster virus (B): This virus causes shingles and can rarely lead to lung complications, but it is not a common cause of lung abscesses.

Staphylococcus aureus (D): While this bacterium can cause pneumonia and other lung infections, it is not the most common cause of lung abscesses.

Tetany is caused by:

 # Tetany is caused by:

A. Hyperglycemia 

B. Hypocalcemia 

C. Clostridium tetani 

D. Low oxygen level

The correct answer is B. Hypocalcemia.

Tetany is a condition characterized by involuntary muscle contractions, cramps, and spasms. The primary cause of tetany is hypocalcemia, which is a low level of calcium in the blood. Calcium plays a crucial role in muscle contraction and nerve function. When calcium levels are low, nerves become hyperexcitable, leading to the uncontrolled muscle contractions seen in tetany.

Hyperglycemia (A): High blood sugar levels are associated with diabetes, not tetany.

Clostridium tetani (C): This bacterium causes tetanus, a different condition characterized by muscle stiffness and spasms.

Low oxygen level (D): While low oxygen can cause various symptoms, it is not the primary cause of tetany.

Reference: Hypocalcemia and Tetany: Causes, Symptoms, and Treatment (webmd.com)