If you are concerned with tooth decay, one option would be to brush his teeth. If you haven’t been checking his teeth and gums on a routine basis he may not like you doing this at first. Start slowly by inspecting his mouth daily and this will help when you actually start to brush them. If you don’t want to go there then introducing chew items shouldn’t be a problem, I don’t see him chewing on other things since it hasnt been in his behavior to do so, if he starts to show interest in chewing things that you don’t want him to, just correct it and give him something to chew
on that is allowed.