title: Combined Treatment Effects Using Bioactive-Coated Implants and Ceramic Granulate in a Rabbit Femoral Condyle Model.
abstract: BACKGROUND
  Resolution of peri-implant defects resulting from implant placement in the freshly extracted site demands for a bone graft substitute that stimulates bone regeneration and hence facilitates implant integration. In view of this, the addition of silica to hydroxyapatite (HASi) could enhance the bioactive behavior of ceramic materials and implant surfaces coated with bioactive ceramics might benefit the interaction between bone and implant.
  
  
  OBJECTIVE
  To evaluate the bone response to implants coated with hydroxyapatite-silica (HASi) or hydroxyapatite (HA) and either or not combined with HASi and HA ceramic bone substitute particles, respectively, on bone-to-implant contact (BIC) and bone formation using a rabbit femoral condyle implant model with a gap design.
  
  
  METHODS
  A total of 32 custom-made, titanium implants (Ti: diameter 5 mm, length 8 mm) with two-sided gaps were fabricated and coated with either HASi or HA using pulsed laser deposition (PLD). The implants were installed bilaterally in the femoral condyles of 16 New Zealand white rabbits. According to a randomization protocol, one gap of HASi-coated and HA-coated implants was filled with HASi particles and HA particles, respectively, and the other gap was left empty. After an implantation period of 8 weeks, the retrieved specimens were analyzed via histology and histomorphometry (i.e., bone to implant contact [BIC] and bone volume [BV]).
  
  
  RESULTS
  The BIC and BV around the implants were analysed for HASi- and HA-coated implants with and without the use of HASi and HA bone substitute material. Comparison of HASi- and HA-coated implants showed similar BIC for HASi- (55.7 + 11.0) and HA-coated implants (50.3 + 19.7). When coated implants were combined with bone substitute materials, HASi-coated and particle-filled implants showed higher BIC (64.3 ± 6.8%) compared with HA-coated and HA-filled implants (54.5 ± 10.9%). Similarly, the BV within the region of interest showed significantly higher values for the HASi-coated and HASi-filled implants (21.1 ± 1.7%) compared with HA-coated and HA-filled implants (12.8 ± 4.9%).
  
  
  CONCLUSIONS
  Within the limitations of this study, it can be concluded that silicon substitution in HA favors bone regeneration compared with HA, especially when used as bone substitute material. Further studies using different healing periods will elucidate the resorption pattern of HASi granules in comparison with HA.
authors.affiliation: Department of Periodontics and Community Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Reghunathan S
authors.initials: RS
authors.lastname: Preethanath
authors.affiliation: Bioceramic Laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India.
authors.forename: Palangadan
authors.initials: P
authors.lastname: Rajesh
authors.affiliation: Bioceramic Laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India.
authors.forename: Harikrishna
authors.initials: H
authors.lastname: Varma
authors.affiliation: Department of Periodontics and Community Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Sukumaran
authors.initials: S
authors.lastname: Anil
authors.affiliation: Department of Biomaterials, Radboudumc, Nijmegen, The Netherlands.
authors.forename: John A
authors.initials: JA
authors.lastname: Jansen
authors.affiliation: Department of Biomaterials, Radboudumc, Nijmegen, The Netherlands.
authors.forename: Jeroen J J P
authors.initials: JJ
authors.lastname: van den Beucken
mesh_terms: D000818:Animals; D001861:Bone Regeneration; D018786:Bone Substitutes; D002516:Ceramics; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017886:Durapatite; D005269:Femur / Q000166:cytology / Q000502:physiology; D020007:Implants, Experimental; D053685:Laser Therapy; D023421:Models, Animal; D011817:Rabbits; D012822:Silicon Dioxide; D014025:Titanium
chemical_list: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D012822:Silicon Dioxide; D017886:Durapatite; D014025:Titanium
keywords: bone grafting; bone substitute; histology; histomorphometry; hydroxyapatite; hydroxyapatite silica; intrabony defects; pulsed laser deposition