Abstract
BackgroundThe subcrestal placement of implant platform has been considered a key factor in the preservation of crestal bone, but the influence of implant placement depth on bone remodeling combined with peri-implantitis is not fully understood. The aim of this study was to assess the effect of the crestal or subcrestal placement of implants on peri-implant bone defects of ligature-induced peri-implantitis in dogs.Material and MethodsEight weeks after tooth extraction in six beagle dogs, two different types of implants (A: OsseoSpeed™, Astra, Mölndal, Sweden; B: Integra-CP™, Bicon, Boston, USA) were placed at either crestal or subcrestal (-1.5 mm) positions on one side of the mandible. Ligature-induced peri-implantitis was initiated four weeks after the installation of the healing abutment connections. After 12 weeks, tissue biopsies were processed for histological analyses.ResultsSupra-alveolar bone loss combined with a shallow infrabony defect was observed in crestal level implants while deep and wide infrabony defects were present in subcrestal level groups. Subcrestal groups showed significantly greater ridge loss, depths and widths of infrabony defects when compared to crestal groups (P<0.001).ConclusionsWithin the limitations of the animal study, it can be stated that the implants at subcrestal position displayed greater infra-osseous defect than implants at crestal position under an experimental ligature-induced peri-implantitis. Key words:Subcrestal, peri-implantitis, histology.
Highlights
Subcrestal implant placement in esthetic areas has been a common treatment modality in order to maintain the mucosa texture and tonality, as well as provide sufficient space to achieve an ideal emergence profile [1,2]
The main effect of implant-abutment interface (IAI) placement depth was significant for ridge loss, Ridge-fBIC and HBL values (P < 0.001, P < 0.001 and P < 0.001, respectively), with mean ridge loss, depths of infrabony defect (Ridge-fBIC), and the widths of infrabony defect (HBL) significantly greater for the subcrestal groups compared to the crestal groups
Compared to other studies, which inserted implants at crestal level under ligature-induced peri-implantitis [19,20], the depths and widths of infrabony defect obtained in this study show similar results
Summary
Subcrestal implant placement in esthetic areas has been a common treatment modality in order to maintain the mucosa texture and tonality, as well as provide sufficient space to achieve an ideal emergence profile [1,2]. Clinical studies utilizing implants with tapered internal IAI inserted at subcrestal levels presented contradictory results with respect to peri-implant bone loss [8,9,10,11,12]. The main effect of IAI placement depth was significant for ridge loss, Ridge-fBIC and HBL values (P < 0.001, P < 0.001 and P < 0.001, respectively), with mean ridge loss, depths of infrabony defect (Ridge-fBIC), and the widths of infrabony defect (HBL) significantly greater for the subcrestal groups compared to the crestal groups.
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