Abstract: A dental implant assembly for supporting a dental component on a patient's jawbone. The dental implant assembly is fitted into a hole drilled in the jawbone. The dental implant assembly comprises an implant member having a hollow bottom sleeve split into multiple segments, a fixed shaft located inside the split bottom sleeve, and an expander member movably mounted on the fixed shaft and having a ramped surface engaging with the at least two split segments. The expander member is engaged with the bottom of the jawbone hole, and caused to move on the shaft as the implant member is installed into the jawbone hole, to thereby force the split segments to expand outwardly against and tightly engage with the interior sidewall of the jawbone hole. Therefore, the dental implant assembly can be securely installed into the patient's jawbone in a single step without any additional and separate step to operate the expander.