title: Soft Tissue Integration of Hydroxyapatite-Coated Abutments for Bone Conduction Implants.
abstract: OBJECTIVE
  The protocol for bone conduction hearing implant surgery involves reduction of soft tissues around the abutment to minimize the risk of skin-related complications. The present investigation was undertaken to demonstrate that hydroxyapatite-coated abutments provide improved soft tissue integration compared with conventional (pure titanium) abutments and are suitable for use without surgical removal of subepidermal soft tissues.
  
  
  METHODS
  Forty-eight implants for bone conduction with two different types of abutments (test and control) were inserted in the skull parietal part of eight sheep. Test abutments had a hydroxyapatite-coated surface and a concave shape. Conventional titanium abutments were used as controls. A follow-up time of 4 weeks was used. Histomorphometric analyses of test and control samples were analyzed, and morphometric results were compared using mixed model analysis.
  
  
  RESULTS
  Histological assessment showed healthy soft tissues around the abutments with limited or no signs of inflammation. Hydroxyapatite-coated abutments showed intimate dermal adherence, while less close contact was noted for control abutments. Statistically significant differences in mean pocket depth (0.4 vs 1.6 mm, p = .0013) and epidermal downgrowth (0.6 vs 2.0 mm, p = .0003) between test and control abutments were recorded.
  
  
  CONCLUSIONS
  The study confirms that hydroxyapatite-coated abutments resulted in a significant reduction in pocket depth and improved soft tissue integration compared with conventional titanium abutments, possibly by providing tight adherence at the interface. Statistically significant reduced pocket depth formation and epidermal downgrowth were recorded.
authors: Oral & Maxillofacial Surgery, Department of Odontology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors: Anna
authors: A
authors: Larsson
authors: Cochlear Bone Anchored Solutions AB, Mölnlycke, Sweden.
authors: Marcus
authors: M
authors: Andersson
authors: Cochlear Bone Anchored Solutions AB, Mölnlycke, Sweden.
authors: Stina
authors: S
authors: Wigren
authors: Statistiska Konsultgruppen, Gothenburg, Sweden.
authors: Aldina
authors: A
authors: Pivodic
authors: Cochlear Bone Anchored Solutions AB, Mölnlycke, Sweden.
authors: Mark
authors: M
authors: Flynn
authors: Oral & Maxillofacial Surgery, Department of Odontology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors: Ulf
authors: U
authors: Nannmark
mesh_terms: D000818:Animals; D001844:Bone Conduction; D000044:Dental Abutments / Q000009:adverse effects; D017886:Durapatite / Q000627:therapeutic use*; D005260:Female; D005881:Gingiva / Q000033:anatomy & histology / Q000502:physiology*; D005888:Gingival Pocket / Q000209:etiology; D012756:Sheep; D014025:Titanium / Q000627:therapeutic use
chemical_list: D017886:Durapatite; D014025:Titanium
keywords: bone-anchored hearing aid; hearing aids; hydroxyapatite; minimally invasive surgery