The planned study is a secondary care-based prospective, multi-center two-arm, parallel-group, randomized controlled trial at three pediatric university dental clinics in Germany. We plan to enroll 300 patients with one or more deeply carious, sensitive and non-symptomatic deciduous molar. One molar per patient will be randomly allocated to receive one of two treatments (selective or stepwise excavation). Total follow-up time will be three years after completion of the initial treatment. Success, survival and restoration integrity will be assessed after one, two and three years. Patients', parents' and dentists' preference will be assessed after each treatment using visual-analogue scale or Likert-rating scales. Costs will be assessed for initial and follow-up treatments and will be based on a micro-costing approach.