The traditional treatment of deep carious lesions approaching the pulp is dictated by removing all of the soft demineralized dentin in one visit. However, several studies has been challenged this approach. Removing caries in stages over two visits some months apart allow pulp time to form reparative dentin reduces the risk of pulp exposure. The purpose of this randomized clinical trial study is to access the prevalence of pulp exposure after stepwise (two-step) versus direct complete (one-step) excavation of permanent teeth with deep carious lesion. Secondary objects are to access patient experience of symptoms of pulpal inflammation or necrosis and tooth remineralization.108 patients, 18 years of age, presenting permanent tooth with deep carious lesion will be randomly assigned to three different treatments (n=36): Group 1 (Direct complete excavation-Control Group): all identifiable, irreversible infected dentin will be completely removed prior to definitive restorative procedure. Group 2 (Calcium Hydroxide): Irreversibly infected dentin will be partially removed and calcium hydroxide will be applied. Group 3 (MTA-Mineral Trioxide Aggregate): Irreversibly infected dentin will be partially removed and MTA will be applied. For Groups 2 and 3 teeth will be sealed with a temporary restoration and definitive restoration will be placed after 3 months. Control and experimental groups will be evaluated every 3 months during 12 months. Specific statistical tests will be used to analyze outcome measures: number of pulp exposure during caries removal, patient experience of symptoms of pulpal inflammation or necrosis and percentage of dentin remineralization. A p-value of less than 0.05 will be considered statistically significant. This clinical study presents an alternative and more conservative approach to traditional caries removal for deep caries lesion. The authors are proposing the use of MTA, a potent reparative dentin material, which has never been evaluated for two-step technique in clinical trials.