Inclusion Criteria:  Signed Informed Consent Form Adult subjects (18 years or older)  Subjects with 3.1. conductive or mixed hearing losses with pure tone average (PTA) bone conduction (BC) threshold (measured at 0.5, 1, 2 and 3 kHz) of the indicated ear better than or equal to 45 dB HL.  3.2. OR subjects who have a profound sensorineural hearing loss in one ear and normal hearing in the opposite ear (i.e. SSD). The pure tone average (PTA) air conduction (AC) threshold of the hearing ear should then be better than or equal to 20 dB HL (measured at 0.5, 1, 2 and 3 kHz) 3.3. OR subjects who are indicated for an air-conduction contralateral routing of signals (ACCROS) hearing aid, but who for some reason cannot or will not use an AC CROS.  Fluent in local language Subjects who have the ability and are willing to follow investigational procedures/requirements, e.g. to complete quality of life scales.  Exclusion Criteria:  Inability to undergo general or local anesthesia Prior implantation with percutaneous device or middle ear implant on the side to be implanted Known medical conditions that contraindicate undergoing surgery as judged by the investigator Untreated ongoing middle ear infection at the time of surgery Known insufficient bone quality/quantity/depth or skull size (scull abnormalities) for implantation of a Sentio Ti Implant Known or suspected contact allergy to silicone or other material used in the Sentio system. Known condition that could jeopardize wound healing and skin condition e.g. uncontrolled diabetes over time as judged by the investigator. Known skin or scalp conditions that may preclude attachment or interfere with the usage of the sound processor. Known retro cochlear pathology and auditory processing disorders that may have an impact on the outcome of the investigation Any other known condition that the investigator determines could interfere with compliance or investigation assessments. Use of ototoxic drugs that could be harmful to the hearing, as judged by the investigator. Subject that has received radiotherapy in the area of implantation or is planned for such radiotherapy or similar during the investigation period. For bilateral asymmetric candidates, subject already treated with a bone-anchored hearing solution on the side with the best bone conduction thresholds Known chronic or non-revisable vestibular or balance disorder Known abnormally progressive hearing loss For conductive and mixed losses: evidence that hearing loss is retro-cochlear or of central origin Participation in another clinical investigation with pharmaceuticals and/or devices which might cause interference with investigation participation. Use of active implantable or body worn device that for medical reasons cannot be removed or discontinued, such as implantable cardiac pacemakers, defibrillators, or neurostimulators. Known need for frequent MRI investigations for follow-up of other diseases. Any subject that according to the Declaration of Helsinki is deemed unsuitable for investigation enrolment.