If they don’t already have a number of certificates behind their desk, it’s worth asking their qualifications and skills in dental implants. In NZ, they should have Health Sciences first year, and then a four-year Bachelor of Dental Surgery. In NZ, this only is available at Otago University. Then they will have a post-graduate qualification or accreditation in dental implantation.
Be hesitant about anyone who doesn’t commit to ongoing learning. The technology behind implants is constantly changing, and in order for the best results, dentists need to be always learning. If they’ve learned nothing since they’ve completed their degree, give them a wide berth.