Pit &fissure least effective with- Procedure done before applying pit & fissure sealant.. primary molar

1- Pit &fissure least effective with:

• A- tweny-four month year.
• B- primary molar.
• C- 2nd molar.

2- Procedure done before applying pit & fissure sealant:

• A- Acid etch by phosphoric acid.

Answers To Questions:

1. Pit & Fissure least effective with:

While all teeth with pits and fissures can benefit from sealants, there are factors that can affect their effectiveness. Among the options you provided:

B. Primary Molar:

This is generally NOT the least effective option. Primary molars are actually good candidates for pit and fissure sealants because they are more susceptible to caries due to their thinner enamel and deeper grooves. They also serve as space holders for permanent teeth, so protecting them is crucial. 

A. Twenty-four-month-old:

Age isn't the primary factor. Sealants can be effective throughout childhood and even in adults. However, earlier application tends to provide longer protection as children are more susceptible to caries, and sealants deteriorate and wear over time.

C. Second molar:

This could be considered the least effective option among the given choices. Second molars typically have deeper and more complex pits and fissures, making it more challenging for sealants to fully occlude and seal them effectively. Additionally, due to their location further back in the mouth, proper placement and monitoring of the sealant might be slightly more difficult. 

However, it's important to note that even with potential challenges, sealants can still be beneficial for second molars and should be considered as a preventive measure.

2. Procedure done before applying pit & fissure sealant:

A. Acid etch by phosphoric acid (30-37%) is indeed the correct answer.

This step is crucial for ensuring proper adhesion of the sealant to the tooth surface.

How to work:

Here's how it works:

- Acid etching:

The phosphoric acid dissolves a thin layer of enamel, creating microscopic pores.

- Rinse and dry:

The etched surface is then thoroughly rinsed and dried to remove any debris.

- Sealant application:

The sealant is flowed onto the prepared surface and light-cured to harden it.

Acid etching increases the surface area and creates a rougher texture, allowing the sealant to mechanically interlock with the enamel for a strong and lasting bond.