Is it permissible to recite the Qur’an with the intention of regenerating teeth, and is this considered an transgression in supplication, given the existence of individual stories of people for whom this occurred?

Allah has forbidden transgression in supplication (Du'a). One form of this is asking Allah for something He does not do, such as requesting the regrowth of teeth for an adult. This contradicts the established norm upon which Allah created humans, as teeth grow only twice in a lifetime. As for the circulated stories about teeth regrowing, they are mostly lies with no basis, and one should not believe everything heard or read. Even if a miraculous act (karamah) occurs for someone by Allah's will, it does not mean that we should supplicate for things that contradict the norm without necessity.