Clinical Implant Dentistry and Related Research

One-piece vs. two-piece implants at 15+ years: better bone, but at what cost?

Pirc M, Pala K, Rusch F

Source study: Outcomes of One-Piece and Two-Piece Dental Implants After 15-17 Years: Follow-Up of a Randomized Clinical Trial. — Clinical Implant Dentistry and Related Research

In brief

  • Overall implant survival reached 95% at 15-17 years, with two-piece implants showing higher survival (98.0%) than one-piece (91.8%) in this cohort.
  • One-piece implants preserved marginal bone significantly better (0.08 mm loss vs. 1.53 mm for two-piece) over the long term.
  • Technical complications were markedly higher with one-piece implants: 35.4% at implant level vs. 5.8% for two-piece, requiring substantially more prosthetic intervention.
  • Peri-implant mucositis was recorded in 49.7% of implants and peri-implantitis in 13.3%, with higher rates in the one-piece group.

Long-term data on dental implant outcomes remain among the most valuable evidence in implantology, and this study provides a rare 15-17-year follow-up of a randomized clinical trial comparing one-piece (STM) and two-piece (BRA) implant systems.

From an original cohort of 60 patients, 39 patients with 95 implants completed the long-term follow-up (STM: 22 patients/45 implants; BRA: 17 patients/50 implants), with a mean follow-up of 16.4 ± 1.1 years. The cumulative implant survival rate was 95.0% overall (STM: 91.8%; BRA: 98.0%).

Marginal bone levels told a nuanced story. At 15-17 years, the one-piece system showed superior marginal bone preservation (0.08 ± 1.15 mm) compared to the two-piece design (1.53 ± 0.81 mm). This difference is clinically meaningful over such a long horizon. However, the one-piece system carried a substantially higher rate of technical complications — 35.4% at implant level versus just 5.8% for two-piece. These included prosthetic complications over the 23 affected implants in the STM group versus only 5 in the BRA group.

Biological complications were also documented: peri-implant mucositis was observed in 49.7% of all implants and peri-implantitis in 13.3%, with higher rates in the STM group. Bleeding on probing was higher in the one-piece group. Esthetic observations included visible crown margins in 62 implants and mucosal shimmering in 54 implants; no implant fractures were reported.

The clinical takeaway is a clear trade-off: one-piece implants preserve bone better but demand more prosthetic maintenance. Two-piece systems offer greater prosthetic reliability with acceptable bone remodeling. These 15+ year data help clinicians make informed design choices based on patient-specific priorities.

Why it matters in practice

Rare 15+ year RCT data on implant design are scarce; this study quantifies a clinically meaningful trade-off that should inform patient selection: one-piece implants offer a bone-preservation advantage but require accepting a substantially higher burden of prosthetic maintenance, while two-piece systems deliver greater long-term prosthetic reliability at the cost of more marginal bone remodeling.

This summary is automatically generated from the original abstract and curated by Dr. Ernesto Bruschi. Always refer to the original publication for clinical decisions.
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