Still little bit numbness in teeth due to chin implant surgery after three years - Normal?

Hello! Thank you for your question! Numbness after any surgical
procedure is expected for several weeks to months following. As the
nerves to the area are traumatized and will then experience a temporary
neuropraxia, a transient loss of nerve conduction. This usually
resolves over the next 6-12 weeks, but depending on the procedure
performed, sometimes much longer. Typically this should resolve by 1
year. As it goes past this date, the likelihood of the sensation
returning is small. However, it can take up to 2 years. If no return
from there, it is unlikely to return. It should be discussed that
persistent sensory changes may develop following any surgical
procedure.  This is not common, but if new, the implant may have migrated and need adjustment.  Followup with your surgeon for evaluation.  The usual signs of the nerves regenerating and neuropraxia
resolving is itching, followed by a burning sensation and then
occasional sharp, shock-like pains. These will be normal to experience,
and actually a promising sign. Usually, normal sensation returns, but
is is also possible to have decreased sensation or even increased
sensation to the areas affected. Re-educating nerves postoperatively is
often helpful and will allow proper instruction for the affected
sensory nerves - methods include using different textures to the
affected areas when showering, bathing, applying lotion, etc. If
bothersome, there are some medications that may be helpful, including
Neurontin for pain for hypersensitivity. You can try various textures
such as washcloths, loofahs, cotton sheets, etc. Massaging the areas is
also beneficial for the incision to make the finest scar possible. The
last place to regain the sensation will be directly adjacent to the
incision/scar as the nerves will make its way from the periphery to this
location. If continual pain arises, evaluation is warranted. After
ruling out other causes, one rare explanation may be that a neuroma has
developed and may require surgical excision. This is very unlikely
unless a large sensory nerve has been transected inadvertently during
the procedure. Hope that this helps! Best wishes!

I recommend that you see your surgeon to determine whether the implant has either migrated or eroded into the bone.  An xray might be helpful to determine this.  Your symptoms are not common after routine chin implantation.