Clinical tests that are commonly used to evaluate tissues surrounding natural teeth are also used in implant dentistry. It is unclear if they are equally valid and reflect the condition of the bone surrounding an implant reliably. This study evaluates the use of a plaque index, a gingiva index, the assessment of a probing depth and the Periotest value and relates the findings to the image on a radiograph in 16 patients, involving 32 IMZ implants. All four clinical tests showed poor sensitivity and, in general, only fair specificity when observations from the image on the radiograph were interpreted as the 'golden standard' for the presence or absence of pathology adjacent to the implant. Frequently, based on any clinical parameter, disease was not diagnosed, while the radiograph did show pathological loss of bone at the bone-implant contact area. It is concluded that the aforementioned parameters are unreliable and unfit for clinical evaluation in implant dentistry. Radiographs are needed to evaluate critical marginal bone changes surrounding dental implants.