Dental implants show longevity after four decades

Iveta Ramonaite, Dental Tribune International

Wed. 2. April 2025

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GOTHENBURG, Sweden: Single-tooth implants have demonstrated high success rates over observation periods of five to ten years. However, long-term monitoring remains essential. Researchers at the University of Gothenburg have recently conducted the longest follow-up study yet on implant survival and complication rates, evaluating single implants placed 38–40 years ago. Their findings confirmed that the implants remained fully functional but that the implant-supported crowns exhibited comparatively shorter lifespans. The study offers valuable insights into potential long-term complications and reinforces confidence in the longevity of single-tooth implant treatments.

Lead author Sargon Barkarmo. (Image: Elin Lindström)

The study included 13 individuals who received 18 single implants placed using a two-stage protocol with delayed loading, and none received bone grafts. The implants were developed based on research conducted at the University of Gothenburg under the leadership of the late Prof. Per-Ingvar Brånemark—a distinguished Swedish physician and researcher widely recognised as the father of modern dental implantology and the pioneer of osseointegration.

Lead author Sargon Barkarmo, a prosthodontist and senior lecturer at the university, expressed enthusiasm regarding the long-term effectiveness of the implants, which showed an impressive cumulative survival rate of 95.6%. He commented in a university press release: “Even though the study included a small number of patients, the results show that the implants remain in place and that the bone loss around them is virtually unchanged after 40 years. This confirms that the foundation Brånemark established still holds.”

Although peri-implant mucositis was common among the study participants, no peri-implantitis was diagnosed. Nonetheless, several implants exhibited probing depths of ≥ 6 mm, indicating the necessity of ongoing clinical monitoring. Plaque was observed on all the teeth and implants during the follow-up visit, and the mean plaque index was 16.9% ± 11.6%. The bone levels surrounding all the implants remained remarkably stable over the study period, and many even showed slight bone gain.

Senior author Dr Jan Kowar. (Image: Elin Lindström)

In contrast to the high implant survival, the implant-supported crowns had a notably shorter lifespan. Only 60.9% of the original crowns remained in place. Out of 18 crowns, six were cement-retained. Senior author Dr Jan Kowar, a prosthodontist and senior lecturer at the university, explained that aesthetic concerns, rather than technical failures, were the primary reason for crown replacements. He noted that developing innovative crown materials could significantly advance long-term outcomes for implant treatments.

Despite the relatively small sample size, the study highlights the excellent long-term success of single-tooth implant systems while acknowledging the increasing likelihood of crown replacements over extended periods. The authors stressed that longer follow-up studies are crucial for better understanding implant longevity and potential complications, particularly because many of the patients who receive single implants are young and are thus expected to maintain their implants for decades. Barkarmo noted: “Today, methods that accelerate treatment and healing are commonly used. These approaches also need long-term follow-ups and careful evaluation to ensure equally good results over time.”

The study, titled “Outcome of single dental implants over 38–40 years: A long-term follow-up study”, was published online in the February 2025 issue of Clinical Implant Dentistry and Related Research.