What MDM are you using? There’s a Cloud Customer 360 product that is native to Force platform which can de-duplicate the Salesforce accounts and also show DNB hierarchy between those accounts.
If using MDM multi-domain on prem then there’s no OOTB integration to Salesforce. You need ETL like Informatica powercenter with Salesforce connector or any ESB layer like Mulesoft for integration.
Sathiesh M | Infa GCS-MDM