Long‐Term Impact of 1‐mm Versus 3‐mm Definitive Abutments on Marginal Bone Loss and Peri‐Implant Disease: A 7‐Year Randomised Clinical Trial

• Published in: Journal of clinical periodontology
• Main Authors: Muñoz, Marta, Pardo, Germán, Vilarrasa, Javi, Babiano, Álvaro, Ruíz‐Magaz, Vanessa, Nart, José
• Format: Journal Article
• Language: English
• Published: United States 18.08.2025
• Subjects: peri‐implant status; marginal bone level; bone level; peri‐implant maintenance therapy; long‐term studies; dental implant; peri‐implantitis; abutment height
• ISSN: 0303-6979; 1600-051X; 1600-051X
• DOI: 10.1111/jcpe.70009

To evaluate bone level changes in implants with 1-mm- or 3-mm-high abutments over a 7-year period and to investigate the role of abutment height upon peri-implant status. Two-piece implants were placed 1.5 mm subcrestally with either 1-mm (control) or 3-mm (test) high definitive abutments. Marginal bone level change from the first to seventh year was the primary outcome. Peri-implant status and other patient and peri-implant clinical variables (smoking, peri-implant maintenance therapy compliance, interproximal hygiene, vertical soft tissue thickness and keratinised mucosa width) were also assessed. After 7 years, 37 subjects (63 implants) were analysed: 17 subjects with 32 implants in the 1-mm abutment group, and 20 subjects with 31 implants in the 3-mm abutment group. Significant differences in marginal bone level changes were observed at 7 years. The 3-mm abutment group showed smaller changes compared to the 1-mm abutment group at mesial sites (-0.27 ± 1.32 mm vs. -0.42 ± 0.50 mm, respectively) and distal sites (-0.33 ± 1.39 mm vs. -0.35 ± 0.38 mm), with both differences being statistically significant (p < 0.001). In the control group, 18 implants (54.6%) presented peri-implant mucositis and 6 implants (18.2%) showed peri-implantitis. In the test group, 23 implants (74.2%) presented peri-implant mucositis and 1 implant (3.2%) showed peri-implantitis. No statistically significant differences were found (p = 0.158). Subcrestally inserted implants with 3-mm definitive abutments experienced minimal bone loss over long-term follow-up compared to 1-mm abutments. However, since the differences were not statistically significant, no conclusions could be drawn on the protective effect against peri-implantitis.