Gums (gingiva) can recede around an implant for a few different reasons including; 1) something stuck in the gums around the implant tooth, 2) periodontal disease (periodontitis), or 3) natural order of events.
First, anything stuck in the gums around the implant tooth will make the gums bleed, maybe puss, and eventually recede. This could be food continually getting impacted between the teeth or something as a little bit of extra cement from the crown being put on. The cement can be cleaned our; however, if there is a food trap (small gap between the teeth), the gap will have to be closed to stop the recession.
Secondly, when an implant is put in, no one is worried about a cavity as titanium, porcelain, or zirconia do not grow cavities. However, an implant can still get periodontitis only in this case it is called peri-implantitis. The gums around the implant need to be kept clean just like any other tooth; otherwise they will recede.
Finally, Titanium and titanium alloys are used for implants because they have what is known as bio compatibility. This means that they are the most compatible with a persons biological tissues (the do not cause a reaction and go undetected by the body's immune system). This is why hip implants, rods and screws used in the body are made out of titanium. However, in some cases the body will reject the implant and the gums around it will recede. Hope this helps.
My best to you
William F. Scott IV, DMD
Dr. Mark Berkowitz