title: Effect of radiotherapy on osseointegration of dental implants immediately placed in postextraction sites of minipigs mandibles.
abstract: BACKGROUND
  The aim of this study was to compare the osseointegration and the survival of dental implants (DIs) immediately placed in postextraction sites, in mandibles of minipigs that underwent radiotherapy (RT).
  
  
  METHODS
  Twelve Brazilian minipigs were divided into the following groups: A, control; B, implants placement 15 days before RT; C, implants placement 3 months after RT. Implant loss rate (ILR), fibrointegration rate (FIR), bone-implant contact (BIC), and bone density inside the threads (BDIT) were determined in each group 90 days after implantation.
  
  
  RESULTS
  ILR was higher in group C (68.7%) than in groups B (28.1%) and A (21.9%), (P = 0.001). FIR was more frequent in group C (30%) than in groups B (21.7%) and A (4%), although not statistically significant. The averages of BIC and BDIT were, respectively, 33.1 and 41.5 in group C; 18.5 and 26.6 in group B; and 11.5 and 16.3 in group A (P = 0.003 for both variables).
  
  
  CONCLUSIONS
  RT showed a negative effect in periimplant bone regeneration. The implants placement before RT showed better results compared with the implants performed after RT, suggesting that DIs in head and neck cancer patients must be placed before RT or simultaneously during ablative tumor surgery.
authors.affiliation: *Postgraduate Programme in Oncology, University of São Paulo, São Paulo, SP, Brazil; Staff of Oral and Maxillofacial Surgery Department, Erasto Gaertner Hospital, Curitiba, PR, Brazil. †Chief of Oral and Maxillofacial Surgery Department, Erasto Gaertner Hospital, Curitiba, PR, Brazil. ‡Staff of Oral and Maxillofacial Surgery Department, Erasto Gaertner Hospital, Curitiba, PR, Brazil. §Veterinary of Experimental Surgery Laboratory and Bioterium, Positivo University, Curitiba, PR, Brazil; Associate Professor of Federal University of Parana, Curitiba, PR, Brazil. ‖Chief of Radiotherapy Department, Erasto Gaertner Hospital, Curitiba, PR, Brazil. ¶Scientific Director of Head and Neck Surgery and Otorhinolaryngology Department, Hospital de Cancer de Barretos, Barretos, SP, Brazil; Research Advisor of Postgraduate Programme in Oncology, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Roberta Targa
authors.initials: RT
authors.lastname: Stramandinoli-Zanicotti
authors.forename: Laurindo Moacir
authors.initials: LM
authors.lastname: Sassi
authors.forename: Juliana Lucena
authors.initials: JL
authors.lastname: Schussel
authors.forename: Maria Fernanda
authors.initials: MF
authors.lastname: Torres
authors.forename: Sergio Araquem
authors.initials: SA
authors.lastname: Matos Ferreira
authors.forename: André Lopes
authors.initials: AL
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D015921:Dental Implants; D008297:Male; D008334:Mandible; D016348:Osseointegration; D011878:Radiotherapy; D013552:Swine; D013556:Swine, Miniature; D014081:Tooth Extraction
chemical_list: D015921:Dental Implants