{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T02:24:42Z","timestamp":1777947882813,"version":"3.51.4"},"reference-count":32,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T00:00:00Z","timestamp":1777593600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"ITI research grant","award":["1331-2018"],"award-info":[{"award-number":["1331-2018"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JFB"],"abstract":"<jats:p>Aim: This study aimed to compare two-piece zirconia and two-piece titanium implants inserted into the anterior mandible for removable overdentures in a 3-year randomized split-mouth clinical trial. Methods: Twenty fully edentulous mandibular patients received two zirconia and two titanium implants allocated by computer-generated randomization. The primary endpoint was bleeding-on-probing (BOP) at 12 months. Secondary outcomes included implant survival and success (Albrektsson criteria), marginal bone level changes, peri-implant cytokines (IL-1\u03b2, IL-6, and TNF\u03b1), prosthetic complications, and patient-reported outcomes (PROMs). Results: After 3 years, overall survival was 98.61% and overall success was 84.72%. Titanium implants showed higher success compared with zirconia implants (91.70% vs. 77.78%), while survival was 100% and 97.22%, respectively. Marginal bone loss was significantly greater around zirconia implants at 36 months (p &lt; 0.01). No significant differences were observed in IL-1\u03b2, IL-6, or TNF\u03b1 levels up to 12 months. PROMs revealed a trade-off, with zirconia favored for esthetics and cleaning perception, while titanium was rated superior for stability. Conclusions: Within the limitations of this split-mouth RCT, zirconia implants demonstrated reduced success and inferior marginal bone stability compared with titanium implants in overdenture therapy. Careful case selection and close follow-up appear essential when zirconia implants are used in this indication.<\/jats:p>","DOI":"10.3390\/jfb17050213","type":"journal-article","created":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T09:33:17Z","timestamp":1777627997000},"page":"213","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A 3-Year Split-Mouth Randomized Controlled Clinical Trial of Zirconia and Titanium Implant-Supported Overdentures"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8579-2622","authenticated-orcid":false,"given":"Kristian","family":"Kniha","sequence":"first","affiliation":[{"name":"Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Pauwelsstra\u00dfe 30, 52074 Aachen, Germany"},{"name":"Private Dental Clinic, Dres. Kniha, Rosental 6, 80331 Munich, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5658-2893","authenticated-orcid":false,"given":"Lothar","family":"Rink","sequence":"additional","affiliation":[{"name":"Institute of Immunology, University Hospital RWTH Aachen, Pauwelstra\u00dfe 30, 52074 Aachen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9785-9502","authenticated-orcid":false,"given":"Mark","family":"Ooms","sequence":"additional","affiliation":[{"name":"Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Pauwelsstra\u00dfe 30, 52074 Aachen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katharina","family":"Schaffrath","sequence":"additional","affiliation":[{"name":"Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Pauwelsstra\u00dfe 30, 52074 Aachen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7023-991X","authenticated-orcid":false,"given":"Stephan Christian","family":"M\u00f6hlhenrich","sequence":"additional","affiliation":[{"name":"Department of Dentistry, Section of Orthodontics, Dentofacial Orthopedics and Craniofacial Biology, Radboud University Medical Centre, THK 309, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Frank","family":"H\u00f6lzle","sequence":"additional","affiliation":[{"name":"Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Pauwelsstra\u00dfe 30, 52074 Aachen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2160-4527","authenticated-orcid":false,"given":"Ali","family":"Modabber","sequence":"additional","affiliation":[{"name":"Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Pauwelsstra\u00dfe 30, 52074 Aachen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9205-6065","authenticated-orcid":false,"given":"Marius","family":"Heitzer","sequence":"additional","affiliation":[{"name":"Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Pauwelsstra\u00dfe 30, 52074 Aachen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1111\/prd.12180","article-title":"Zirconia dental implants: Where are we now, and where are we heading?","volume":"73","author":"Cionca","year":"2017","journal-title":"Periodontology 2000"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"S2849","DOI":"10.4103\/jpbs.jpbs_1163_25","article-title":"Metal-Free Dental Implants: A Narrative Review of Zirconia and Emerging Alternative Materials","volume":"17","author":"Chappa","year":"2025","journal-title":"J. Pharm. Bioallied Sci."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Abdurakhmon, K., Wu, J., Li, S., and Wei, C. (2025). Biomechanical evaluation of implant materials and connection designs: A structured narrative review of titanium and zirconia. Odontology.","DOI":"10.1007\/s10266-025-01221-2"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1111\/j.1708-8208.2008.00105.x","article-title":"Fracture strength of zirconia implants after artificial aging","volume":"11","author":"Andreiotelli","year":"2009","journal-title":"Clin. Implant. Dent. Relat. Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"844","DOI":"10.1111\/j.1600-0501.2009.01727.x","article-title":"Surface-modified zirconia implants: Tissue response in rabbits","volume":"20","author":"Rocchietta","year":"2009","journal-title":"Clin. Oral Implant. Res."},{"key":"ref_6","first-page":"e90380","article-title":"The Future of Dental Implants: A Narrative Review of Trends, Technologies, and Patient Considerations","volume":"17","author":"James","year":"2025","journal-title":"Cureus"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"30","DOI":"10.11607\/jomi.10500","article-title":"Ceramic Dental Implants: A Systematic Review and Meta-analysis","volume":"38","author":"Neugebauer","year":"2023","journal-title":"Int. J. Oral Maxillofac. Implant."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"567","DOI":"10.5005\/jp-journals-10024-1364","article-title":"Analysis of the peri-implant soft tissues in contact with zirconia abutments: An evidence-based literature review","volume":"14","author":"Pellizzer","year":"2013","journal-title":"J. Contemp. Dent. Pract."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"e694","DOI":"10.1111\/jopr.12766","article-title":"Papilla-Crown Height Dimensions around Zirconium Dioxide Implants in the Esthetic Area: A 3-Year Follow-Up Study","volume":"28","author":"Kniha","year":"2019","journal-title":"J. Prosthodont."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"635","DOI":"10.1111\/j.1600-0501.2008.01543.x-i2","article-title":"The mucosal barrier at implant abutments of different materials","volume":"19","author":"Welander","year":"2008","journal-title":"Clin. Oral Implant. Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1111\/clr.12093","article-title":"Bacterial adhesion on the titanium and zirconia abutment surfaces","volume":"25","author":"Nascimento","year":"2014","journal-title":"Clin. Oral Implant. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"106220","DOI":"10.1016\/j.jdent.2025.106220","article-title":"Clinical performance of immediately loaded zirconia implants: A systematic review with meta-analysis","volume":"164","author":"Alves","year":"2026","journal-title":"J. Dent."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"511","DOI":"10.1902\/jop.2015.150441","article-title":"Evaluation of Hard and Soft Tissue Dimensions Around Zirconium Oxide Implant-Supported Crowns: A 1-Year Retrospective Study","volume":"87","author":"Kniha","year":"2016","journal-title":"J. Periodontol."},{"key":"ref_14","first-page":"11","article-title":"The long-term efficacy of currently used dental implants: A review and proposed criteria of success","volume":"1","author":"Albrektsson","year":"1986","journal-title":"Int. J. Oral Maxillofac. Implant."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1111\/j.1399-302X.1987.tb00298.x","article-title":"The microbiota associated with successful or failing osseointegrated titanium implants","volume":"2","author":"Mombelli","year":"1987","journal-title":"Oral Microbiol. Immunol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1111\/j.1600-0757.1994.tb00013.x","article-title":"Pathogenesis of implant failures","volume":"4","author":"Tonetti","year":"1994","journal-title":"Periodontology 2000"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"230","DOI":"10.1034\/j.1600-0501.1996.070305.x","article-title":"Correlations between radiographic, clinical and mobility parameters after loading of oral implants with fixed partial dentures. A 2-year longitudinal study","volume":"7","author":"Bragger","year":"1996","journal-title":"Clin. Oral Implant. Res."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1149","DOI":"10.3758\/BRM.41.4.1149","article-title":"Statistical power analyses using G*Power 3.1: Tests for correlation and regression analyses","volume":"41","author":"Faul","year":"2009","journal-title":"Behav. Res. Methods"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"175","DOI":"10.3758\/BF03193146","article-title":"G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences","volume":"39","author":"Faul","year":"2007","journal-title":"Behav. Res. Methods"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"217","DOI":"10.11607\/jomi.5598","article-title":"Peri-implant Crestal Bone Changes Around Zirconia Implants in Periodontally Healthy and Compromised Patients","volume":"33","author":"Kniha","year":"2018","journal-title":"Int. J. Oral Maxillofac. Implant."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Robaian, A., Hamed, M.M., Ahmed, Y., and Hassanein, F.E.A. (2025). Comparative Evaluation of Customized CAD\/CAM vs. Stock Titanium Abutments for Immediate Implant Placement in Class II Extraction Sockets: A Randomized Controlled Trial. Dent. J., 13.","DOI":"10.3390\/dj13080371"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"e15010","DOI":"10.7717\/peerj.15010","article-title":"Clinical performance of zirconium implants compared to titanium implants: A systematic review and meta-analysis of randomized controlled trials","volume":"11","author":"Duan","year":"2023","journal-title":"PeerJ"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Abreu, F., Correia, F., Caetano, T., and Faria-Almeida, R. (2025). The Survival Rate of Zirconia Versus Titanium Dental Implants: A Systematic Review. Surgeries, 6.","DOI":"10.3390\/surgeries6010020"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"630","DOI":"10.1111\/clr.14258","article-title":"A randomized clinical trial on zirconia versus titanium implants in maxillary single tooth replacement","volume":"35","author":"Cune","year":"2024","journal-title":"Clin. Oral Implant. Res."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"6279","DOI":"10.1007\/s00784-023-05242-5","article-title":"Survival and success of zirconia compared with titanium implants: A systematic review and meta-analysis","volume":"27","author":"Padhye","year":"2023","journal-title":"Clin. Oral Investig."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1010","DOI":"10.1007\/s12663-024-02409-9","article-title":"Clinical Assessment of the Relationship of Dental Implant Materials (Titanium and Zirconia) and Peri-Implantitis: A Systematic Review","volume":"24","author":"Shrivastava","year":"2025","journal-title":"J. Maxillofac. Oral Surg."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2285","DOI":"10.1007\/s00784-016-1729-z","article-title":"Pro-inflammatory cytokines at zirconia implants and teeth. A cross-sectional assessment","volume":"20","author":"Cionca","year":"2016","journal-title":"Clin. Oral Investig."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"554","DOI":"10.1016\/j.ijom.2018.10.018","article-title":"Experimental peri-implant mucositis around titanium and zirconia implants in comparison to a natural tooth: Part 1-host-derived immunological parameters","volume":"48","author":"Clever","year":"2019","journal-title":"Int. J. Oral Maxillofac. Surg."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"298","DOI":"10.1902\/jop.2016.160245","article-title":"In Vitro Biofilm Formation on Titanium and Zirconia Implant Surfaces","volume":"88","author":"Roehling","year":"2017","journal-title":"J. Periodontol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1186\/s40001-025-02488-5","article-title":"Clinical effectiveness of Zirconia versus titanium dental implants in anterior region: An overview of systematic reviews","volume":"30","author":"Alqahtani","year":"2025","journal-title":"Eur. J. Med. Res."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"354","DOI":"10.1016\/j.prosdent.2022.08.004","article-title":"Attachment systems for mandibular implant-supported overdentures: A systematic review and meta-analysis of randomized controlled trials","volume":"132","author":"Prasad","year":"2024","journal-title":"J. Prosthet. Dent."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"255","DOI":"10.4103\/jips.jips_368_19","article-title":"A systematic review and meta-analysis of the attachments used in implant-supported overdentures","volume":"20","author":"Chaware","year":"2020","journal-title":"J. Indian Prosthodont. Soc."}],"container-title":["Journal of Functional Biomaterials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-4983\/17\/5\/213\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,3]],"date-time":"2026-05-03T04:15:06Z","timestamp":1777781706000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-4983\/17\/5\/213"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,1]]},"references-count":32,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["jfb17050213"],"URL":"https:\/\/doi.org\/10.3390\/jfb17050213","relation":{},"ISSN":["2079-4983"],"issn-type":[{"value":"2079-4983","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,1]]}}}