Which statement is a principle of minimally invasive tooth preparation?

• A. Overlying, unsupported enamel that is weak and prone to fracture should be removed
• B. Preparation width and depth should exceed carious tissue
• C. Non carious pits and fissures should be included
• D. Existing restorations should never be removed

Answer: (A)

Minimally invasive tooth preparation focuses on preserving as much natural tooth structure as possible and removing only material that jeopardizes the restoration’s integrity. When enamel overlying the dentin is unsupported, weak, and prone to fracture, removing that fragile layer helps create a stable, retentive preparation with a solid bonding surface. This proactive removal prevents future fracturing and improves the restoration’s longevity without unnecessarily sacrificing healthy tooth tissue.

Other options would either remove more tooth structure than necessary (exceeding the diseased area), involve removing healthy pits and fissures, or fail to allow proper restoration seal by leaving existing restorations in place when they compromise bonding or fit. The principle here is to eliminate only the enamel that would compromise the restoration, while preserving the surrounding healthy tooth structure.