Many clinical studies and literature reviews have suggested that bar and ball attachments in maxillary and mandibular implant-supported overdentures (ISOs) should be indicated only when there is sufficient interocclusal space (IOS; minimum = 30 mm). The aim of this clinical report was to present the prosthetic rehabilitation of a patient with adenoid cystic carcinoma associated with microstomia due to radiotherapy (IOS = 23 mm). ISOs offer superior retention and greater stability than conventional obturators, so that base extensions were kept to the minimum. Placing the balls parallel to the prosthesis path of insertion is much easier with this treatment modality.