Pretreatment and Immediately after Orthodontic Bonding - Intra Oral Images Dr. Raman Dhungel, BDS, MDS (Orthodontics)

Which of the following is not an antigen-presenting cell?

 # Which of the following is not an antigen-presenting cell?

A. B cell

B. Dendritic cell

C. T cell

D. Macrophage

The correct answer is C. T cell.

Explanation:

Professional Antigen-Presenting Cells (APCs) are specialized immune cells that process and display foreign antigens complexed with Major Histocompatibility Complex (MHC) class II molecules on their surfaces. Their primary role is to present these antigens to T cells to trigger an immune response.

The classical professional APCs are:

Dendritic cells: The most potent APCs, crucial for initiating primary immune responses by activating naive T cells.

Macrophages: Phagocytes that engulf pathogens and present antigens to T cells to sustain ongoing immune responses.

B cells: Internalize antigens via their specific surface antibodies and present them to helper T cells to receive the signals necessary for antibody production.

T cells, conversely, are the "responders." They use their T cell receptors (TCRs) to recognize the antigens presented by the APCs. They do not serve the primary function of capturing and presenting antigens.

Ringer lactate does not contain:

 # Ringer's lactate does not contain:

A. Magnesium

B. Chloride

C. Potassium

D. Sodium

The correct answer is Magnesium.

Ringer's lactate (also known as Hartmann's solution or sodium lactate solution) is an isotonic crystalloid fluid used for intravenous resuscitation and fluid replacement. It is formulated to closely mimic the electrolyte concentration of human blood plasma, but it does not contain magnesium.

Ideally a malocclusion should be treated between the age of:

 # Ideally a malocclusion should be treated between the age of:

A. 5 and 8 years

B. 8 and 10 years

C. 10 to 12 years

D. The age at which a malocclusion is treated depends on the problem involved

The correct answer is: D. The age at which a malocclusion is treated depends on the problem involved.

Explanation: There is no single ideal age to treat all malocclusions. The optimal timing depends on the type and severity of the malocclusion, the patient's growth status, and the treatment objectives.

Examples:

• Early (5–8 years):
  • Crossbites
  • Functional shifts
  • Harmful oral habits
  • Severe skeletal Class III requiring interceptive treatment
  • 
    
• Mixed dentition (8–10 years):
  • Severe crowding
  • Ectopic eruption
  • Functional Class II correction in selected cases
  • 
    
• Late mixed/early permanent dentition (10–12 years):
  • Most comprehensive orthodontic treatments
  • Class II correction during the pubertal growth spurt
  • Alignment after eruption of permanent teeth
  • 
    
• Adolescence or adulthood:
  • Comprehensive orthodontic treatment
  • Orthognathic surgery for severe skeletal discrepancies (after growth completion)