3D diagnostics – i.e. CBCT – has become indispensable in endodontic and endosurgical diagnostics, treatment and control (follow-up) and has become a real "gamechanger" not only for experienced colleagues and specialists. With the increasing complexity of cases, the superimposition-free and dimensionally accurate display of even the smallest details is gaining in impor-tance and offers an excellent assessment of the prognosis of the teeth to be treated, thus allowing a high degree of certainty in treatment planning as well as (evidence-based) patient education. This is especially relevant for endosurgical procedures with their close relationships to anatomically significant structures (e.g.: maxillary sinus or nervous structures). Nevertheless, CBCT requires a high degree of responsibility with regard to the use of ionizing radiation. The ALARA principle ("As Low As Reasonably Achievable") is more and more replaced by ALADA ("As Low As Diagnostically Acceptable"). It is always necessary to decide whether the patient's well-being is more compromised by not taking the X-ray than by the ionizing radiation and its consequences. Even though there is current evidence that exposure to low-dose radiation with a cumulative dose of up to 100 mSv does not appear to increase the risk of cancer, each CBCT-scan is a justifiable, indication-based, case-by-case decision that must always be made on the basis of a thorough history and clinical examination, taking into account any previous images that may be available. Schlagwörter: CBCT, apical surgery, endodontics, microsurgery, radiation exposure, radiography, surgical, treatment outcome