New complete dentures with bilateral balanced occlusion were fabricated for the patients. The patients wore the prosthesis for at least 8 weeks to allow the muscles to adapt. After adaptation to the dentures, 2 dental implants (Astra Tech Implant System, Dentsply Sirona) were placed in the interforaminal region of the mandible. A minimum of 3 months was waited for the dental implants to osseointegrate. After osseointegration, a clinical examination of the prostheses was performed. The clinical examination evaluated the accuracy of the prostheses in terms of occlusion and vertical dimension, their adaptation to the tissue, and the health of the soft tissue. If cracks or fractures were present, the prosthesis was repaired, and if a defect in tissue adaptation was detected, the prostheses were idealized by relining. The OccluSense® computerized occlusion analysis system (Dr. Jean Bausch GmbH \& Co. KG, Cologne, Germany) was used to check occlusion evaluation, masticatory force distribution, and premature contact due to wear. In the case of premature contact, contacts were eliminated and the first bite force (BF) values of patients with correct occlusion were measured. The maximum BF was measured with a forcemeter (Akson, Istanbul, Turkey). The intraoral sensor of the device was placed unilaterally at the level of the 1st molar. To ensure stability, a bite block of the same thickness was placed in the contralateral dental arch. Patients were seated in a comfortable position with the Frankfurt horizontal plane parallel to the horizontal plane. Patients were asked to bite hard for 3 seconds and the measurement was repeated 3 times. To obtain a reliable value, patients rested for 1 minute after each measurement. The maximum BF was accepted as the highest value among the three bite forces. The mean value of the unilateral right and left measurements was used for data analysis. After measurement, the dentures were attached to the Locator Attachments (Zest Anchors LLC, Escondido, USA). Patients had to wait at least 8 weeks to adapt to the implant-supported overdentures. After the adaptation period, the second BF values of the patients wearing complete dentures in the maxilla and implant-supported overdentures in the mandible were measured.

Oral health-related quality of life and patients satisfaction In this phase, patients were asked to complete the OHIP-14 questionnaires to assess their quality of life and VAS forms to assess patient satisfaction. To assess the impact of clinical parameters, age, gender, implant lengths, implant diameters, locator attachment height, attachment color, and interimplant distance were also recorded.

OHRQoL was assessed using the Turkish version of the Oral Health Impact Profile (OHIP-14). Patients were asked to indicate how often the corresponding OHIP parameter occurred in the past month. OHIP-14 contains 14 questions related to 7 different main topics. The 7 main themes are functional limitations, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap. Patients answered the questions as 0 = Never, 1 = Rarely, 2 = Occasionally, 3 = Quite often, and 4 = Frequently. Scoring was based on 7 main categories and 8 data as the sum of all these categories. The total score of the OHIP-14 is at least 0 and the highest score is 56. A low score at the end of the test indicates a positive impact on OHRQoL, while a high score indicates a negative impact.

Patient satisfaction was measured with the questionnaire VAS. The questions in the questionnaires evaluated the comfort of the prosthesis, convenience in chewing, aesthetics, speech, stability, and ease of cleaning. Patients answered the questions with 5=Totally satisfied, 4=Satisfied, 3=Adequate, 2=Not satisfied, 1=Not at all satisfied. Higher scores indicate higher patient satisfaction.