T The main principle of Minimally Invasive Dentistry (MID) inremoval of dentine caries is by techniques that can maintain affected dentin andreduce wasting of healthy dentin. MID techniques include: rotary preparation(bur tungsten carbide, polymer bur) and air abrasion techniques. Theeffectiveness of the three techniques is determined based on time. Objectives:Analyzing the differences in the effectiveness of the perparation technique usingrotary (polymer bur and tungsten carbide) with air abrasion technique against theremoval of dentine caries within 60 and 90 seconds. Methods: Twenty-fourthpieces of maxillary/mandibular teeth with dentine caries were randomized anddivided into 3 groups: polymer bur group, air abrasion, tungsten carbide bur with60 and 90 seconds observation time (n=4). The sample is then prepared andsmeared with detector caries and evaluated by stereomicroscope. Data wereanalyzed using the Kruskal-Wallis test. Results: There was no significantdifference in effectiveness of caries removal between the preparation techniqueswith polymer bur, air abrasion and tungsten carbide bur (p<0.05) within 60 and90 seconds (p<0.05). Conclusion: Rotary preparation techniques (polymer burand tungsten carbide) and air abrasion techniques, have the same effectiveness inremoving dentin caries tissue, both in 60 seconds and 90 seconds cleaning time.