Aim: The purpose of this randomized controlled trial was to investigate whether the minimally invasive approach would result in good clinical success and satisfying aesthetics of monolithic ceramic crowns compared to conventional layered full ceramic crowns, and therefore be an alternative to conventional tooth preparation. Materials and methods: The tested ceramic was lithium-disilicate ceramic (IPS e.max CAD) manufactured with two different processing techniques. Monolithic lithium-disilicate crowns with reduced thickness were compared to conventional full ceramic crowns with a lithiumdisilicate core and layered with aesthetic ceramic. Fifty-two participants with an endodontically treated premolar or molar were randomized into two groups, with twenty-six patients in each group. Each participant received only one crown. In one group participants were provided with a monolithic crown with reduced thickness, while in another group they were provided with a conventional layered crown. The teeth for conventional crowns were prepared with 2 mm occlusal reduction and 1 mm rounded shoulder, while teeth for monolithic crowns were prepared with 1 mm occlusal reduction and 0.6 mm rounded shoulder. All crowns were prepared by the same clinician and manufactured in the same laboratory by the same technician. The clinical success was evaluated in eight categories, and was carried out by the independent clinician who was not involved in the clinical part of the study. The observation period was 36 months, with control appointments every 6 months using modified United States Public Health Service (USPHS) criteria. Apart from clinical success, participants’ aesthetic satisfaction with provided crowns was also assessed using the visual analogue scale (VAS), after the cementation and after one year. The assessment was double blind as both the examiner and the patients did not know which type of crown was provided. Statistical analysis was done using nonparametric tests. Results: There was no significant difference in clinical success between monolithic and conventional layered crowns after 3 years. One monolithic crown fractured while all other were intact and the survival rate was 96%. All layered crowns were intact and the survival rate was 100%. The median patients’ aesthetic satisfaction for both crowns was very high (99%). Conclusion: The results of this study indicate that the minimally invasive approach can be a good alternative to conventional tooth preparation. IPS e.max lithium-disilicate ceramic demonstrated an exceptional three-year survival rate independently of the thickness of the material. Apart from this, the thickness of the ceramic did not influence the participants’ aesthetic satisfaction.