Name three tools that can be used for conservative preps.

• A. Milling machine; Drill; Impact hammer
• B. Air abrasion; chemicomechanical caries removal; laser
• C. Prophy cup; Pulp tester; Curette
• D. Phosphoric acid; Bonding agent; Light cure

Answer: (B)

Conservative preps focus on removing only diseased tissue while keeping as much healthy tooth structure as possible, using methods that minimize heat, vibration, and unnecessary removal. Air abrasion accomplishes this by blasting away decayed tissue with a stream of tiny particles and air, which allows selective removal with less pressure and noise than a traditional drill. Chemicomechanical caries removal uses a gel to soften decayed dentin so a hand instrument can lift it away, again targeting only the softened tissue and preserving sound dentin and enamel. Lasers cut away carious tissue with precision and can decontaminate the site, often reducing the need for anesthesia and limiting collateral dentin loss, which fits the goal of a conservative prep.

In contrast, conventional milling machines, drills, and impact hammers rely on cutting away tooth structure with high speed and pressure, which tends to be more invasive and less selective. A prophy cup, pulp tester, and curette aren’t instruments for creating cavity preparations—one is for cleaning, another for vitality testing, and the third for periodontal debridement—so they don’t support a conservative caries-prep approach. Phosphoric acid, bonding agent, and light-curing units are materials used in bonding and cementation after a prep, not tools that perform conservative tissue removal.