Osseointegration of Anodized vs. Sandblasted Implant Surfaces in a Guided Bone Regeneration Acute Dehiscence-Type Defect: An In Vivo Experimental Mandibular Minipig Model

Abstract

Objectives: This controlled preclinical study analyzed the effect of implant surface characteristics on osseointegration and crestal bone formation in a grafted dehiscence defect minipig model.

Material and methods: A standardized 3 mm × 3 mm acute-type buccal dehiscence minipig model grafted with deproteinized bovine bone mineral and covered with a porcine collagen membrane after 2 and 8 weeks of healing was utilized. Crestal bone formation was analyzed histologically and histomorphometrically to compare three implant groups: (1) a novel, commercially available, gradient anodized (NGA) implant, to two custom-made geometric replicas of implant "1," (2) a superhydrophilic micro-rough large-grit sandblasted and acid-etched surface, and (3) a relatively hydrophobic micro-rough large-grit sandblasted and acid-etched surface.

Results: At 2 and 8 weeks, there was no difference between the amount and height of newly formed bone (NBH, new bone height; BATA, bone area to total area) for any of the groups (p > 0.05). First bone-to-implant contact (fBIC) and vertical bone creep (VBC) at 2 and 8 weeks were significantly increased for Groups 2 and 3 compared to Group 1 (p < 0.05). At 8 weeks, osseointegration in the dehiscence (dehiscence bone-implant-contact; dBIC) was significantly higher for Groups 2 and 3 compared to Group 1 (p < 0.05).

Conclusions: The amount of newly formed bone (BATA) and NBH was not influenced by surface type. However, moderately rough surfaces demonstrated significantly superior levels of osseointegration (dBIC) and coronal bone apposition (fBIC) in the dehiscence defect compared to the NGA surface at 2 and 8 weeks.

Trial registration: For this type of study, clinical trial registration is not required. This study was conducted at the Biomedical Department of Lund University (Lund, Sweden) and approved by the local Ethics Committee of the University (M-192-14).

Keywords: SLA; SLActive; TiUltra; anodized; dehiscence type defects; guided bone regeneration; hydrophillic implant surface; implant crestal bone formation; implant surface; osseointegration.

FIGURE 1

Illustration of surgical procedures. (a) implant osteotomy preparation starting from a flattened mandibular alveolar ridge. (b) creation of osteotomy. (c) implant placement with standardized acute‐type buccal dehiscence type defect (3 × 3 × 3 mm). (d) grafting of dehiscence defect with deproteinized bovine bone mineral. (e) coverage with a collagen membrane. (f) primary wound closure.

FIGURE 2

Representative micrographs of histological cross‐sections comparing the healing pattern of grafted dehiscence defects around NGA test implants (1), moderately rough modSLA geometrical clone implants (2), and moderately rough SLA geometrical clone implants (3) after 2 weeks (upper row) and 8 weeks of healing (lower row). Sections were stained with paragon (toluidine blue and basic fuchsin) for microscopic evaluation.

FIGURE 3

Representative micrographs at higher magnification of histological cross‐sections comparing the healing pattern of grafted dehiscence defects around NGA test implants (1), moderately rough modSLA geometrical clone implants (2), and moderately rough SLA geometrical clone implants (3) after 2 weeks (upper row) and 8 weeks of healing (lower row). The 2 and 8 week SLA micrographs have been mirrored to allow for easier viewing. Sections were stained with paragon (toluidine blue and basic fuchsin) for microscopic evaluation.

FIGURE 4

Comparison of histomorphometric parameters between different implant groups after 2 and 8 weeks of healing: (a) NBH, new crestal bone height; (b) BATA, ratio of bone area to total area in the defect; (c) dBIC, bone‐to‐implant contact in the dehiscence defect area; (d) VBC, vertical bone creep; (e) fBIC, first bone‐to‐implant contact. 1—Group 1 NGA test implants, 2—Group 2 moderately rough modSLA geometrical clone implants and 3—Group 3 moderately rough SLA geometrical clone implants. Individual values represent adjusted mean values by mixed linear regression. Error bars designate the 95% confidence intervals. Levels of significance as adjusted according to Dunnett‐Hsu: *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001.