Impact of crestal and subcrestal implant placement in peri-implant bone: a prospective comparative study

摘要

Background: To assess the influence of the crestal or subcrestal placement of implants upon peri-implant bone lossover 12 months of follow-up.Material and Methods: Twenty-six patients with a single hopeless tooth were recruited in the Oral SurgeryUnit (Valencia University, Valencia, Spain). The patients were randomized into two treatment groups: group A(implants placed at crestal level) or group B (implants placed at subcrestal level). Control visits were conducted bya trained clinician at the time of implant placement and 12 months after loading. A previously established standardprotocol was used to compile general data on all patients (sex and age, implant length and diameter, and brushingfrequency). Implant success rate, peri-implant bone loss and the treatment of the exposed implant surface werestudied. The level of statistical significance was defined as 5% (α=0.05).Results: Twenty-three patients (8 males and 15 females, mean age 49.8±11.6 years, range 28-75 years) wereincluded in the final data analyses, while three were excluded. All the included subjects were non-smokers witha brushing frequency of up to twice a day in 85.7% of the cases. The 23 implants comprised 10 crestal implantsand 13 subcrestal implants. After implant placement, the mean bone position with respect to the implant platformin group A was 0.0 mm versus 2.16±0.88 mm in group B. After 12 months of follow-up, the mean bone positionswere -0.06±1.11 mm and 0.95±1.50 mm, respectively - this representing a bone loss of 0.06±1.11 mm in the case ofthe crestal implants and of 1.22±1.06 mm in the case of the subcrestal implants (p=0.014). Four crestal implantsand 5 subcrestal implants presented peri-implant bone levels below the platform, leaving a mean exposed treated surface of 1.13 mm and 0.57 mm, respectively. The implant osseointegration success rate at 12 months was 100% inboth groups.Conclusions: Within the limitations of this study, bone loss was found to be greater in the case of the subcrestalimplants, though from the clinical perspective these implants presented bone levels above the implant platform after12 months of follow-up