Late-placed and early-loaded implants with a moderately rough endosseal hydrophilic surface and a machined implant collar present a reliable treatment option, with positive results after more than 9 years› follow-up.
Successful osseointegration is a key factor in long-term prognosis after implant-supported fixed dental prostheses, along with good marginal bone level and healthy peri-implant mucosa. Various techniques for supporting osseointegration have been evaluated, with the aim to reduce treatment times and improve outcomes. One such modification entails making the implant surface hydrophilic, which may facilitate protein binding and activity of osteoblasts. With limited information available on the mid- and long-term outcomes of such implants, a group of researchers at the University of Bern performed a prospective observational study and report follow-up outcomes at 3 and 8.5–9.5 years.
Dr. med. dent. Konrad Meyenberg
In this study conducted by the dental clinics of the University of Bern, the effectiveness of the super hydrophilic alkaline surface of a “hybrid-design” implant (also referred to as “tissue level» implant) on marginal bone preservation was investigated.
In this case series, 15 patients received a total of 20 implants (specifically, screw-shaped titanium self-tapping dental implants with a super hydrophilic endosseal surface [sandblasted and thermal acid etched] and a 1-mm machined collar, ELEMENT RC INICELL®, Thommen Medical). The implants were late placed, i.e. a minimum of 4 months after dental extraction, and loaded early after 21 days of healing. At the 6-month follow-up, the provisional reconstructions were replaced with a final screw-retained reconstruction.
Dr. med. dent. Konrad Meyenberg
The collar of this implant is machined, the intraosseous part has an SLA surface (sandblasted and acid-etched). This can be considered the gold standard today.
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All 15 patients were available for the 3-year follow-up and all implants were considered clinically stable, giving success and survival rates of 100%. At the later follow-up (at a mean of 9 years and 7 months), 3 patients could not attend the evaluation, but the 16 observable implants were functional with no complications, to continue the 100% survival and success rates. Reconstruction-level success and survival rates were similarly high: at 3 years there was one instance of minor chipping (that could be polished), to give a 100% survival and 94.7% success rate. The restorations all remained in place at the later follow-up, although one major chipping event was resolved by a new restoration, leading to a 100% survival and 93.8% prosthetic success rate.
The marginal bone level reached its lowest point at 3-6 months, stabilizing at 0.76 mm measured from the implant shoulder after 36 months. At the last follow-up, the median marginal bone loss was 0.14 mm, being significantly lower than the 6- and 36-month measurements.
Dr. med. dent. Konrad Meyenberg
The marginal bone runs predictably along the smooth-rough border after healing and initial bone modeling, which is also important with regard to surface-related risks for peri-implantitis.
No biological complications were observed, and patients remained satisfied with their treatment, with a mean score of 9.42/10.
Taken together, the findings of this study suggest that late-placed and early-loaded implants with a hydrophilic, moderately rough surface are a reliable treatment option, with high success and survival rates. Importantly, the patients reported high levels of satisfaction with their treatment, even more than 9 years later. As a future step, a randomized controlled trial with a larger sample size would lend important context to these results and provide a useful comparison with a control group.
