title: Retrospective clinical study of ultrawide implants more than 6 mm in diameter.
abstract: BACKGROUND
  The prognosis of wide implants tends to be controversial. While wider implants were initially expected to result in a larger osseointegration area and have higher levels of primary stability, they were reported to have a relatively high rate of failure. The clinical outcome of ultrawide implants of more than 6 mm in diameter was evaluated through a retrospective study.
  
  
  METHODS
  The investigation was conducted on patients who had received ultrawide implant (≥6 mm diameter) placements in Seoul National University Bundang Hospital from January 2008 to December 2013. Complications were investigated during the maintenance period, and marginal bone loss was measured using periapical radiography. Primary stability immediately after the implant placement and second stability after second surgery or during impression were measured using Osstell®Mentor (Osstell, Sweden) as an implant stability quotient (ISQ).
  
  
  RESULTS
  Fifty-eight implants were placed in 53 patients (30 male, 23 female), and they were observed for an average of 50.06 ± 23.49 months. The average ISQ value increased from 71.22 ± 10.26 to 77.48 ± 8.98 (P< 0.005). The primary and secondary stability shows significantly higher at the mandible than at the maxilla (P< 0.001). However, mean survival rate shows 98.28 %. Average marginal bone loss of 0.018 and 0.045 mm were measured at 12 and 24 months after the loading and 0.14 mm at final follow-up date (mean 46.25 months), respectively. Also in this study, the bone loss amount was noticeably small compared to regular implants reported in previous studies.
  
  
  CONCLUSIONS
  The excellent clinical outcome of ultrawide implants was confirmed. It was determined that an ultrawide implant can be used as an alternative when the bone quality in the posterior teeth is relatively low or when a previous implant has failed.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Gumi-ro 173-82, Bundang-gu, Seongnam City, Gyeonggi-do 13620 South Korea.
authors.forename: Jeong-Kui
authors.initials: JK
authors.lastname: Ku
authors.affiliation: Department of Prosthodontics, Section of Dentistry, Seoul National University Bundang Hospital, Gumi-ro 173-82, Bundang-gu, Seongnam City, Gyeonggi-do 13620 South Korea ; Department of Dentistry and Dental Research Institute, School of Dentistry, Seoul National University, Daehak-ro 101, Jongno-gu, Seoul 03080 South Korea.
authors.forename: Yang-Jin
authors.initials: YJ
authors.lastname: Yi
authors.affiliation: Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Gumi-ro 173-82, Bundang-gu, Seongnam City, Gyeonggi-do 13620 South Korea.
authors.forename: Pil-Young
authors.initials: PY
authors.lastname: Yun
authors.affiliation: Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Gumi-ro 173-82, Bundang-gu, Seongnam City, Gyeonggi-do 13620 South Korea ; Department of Dentistry and Dental Research Institute, School of Dentistry, Seoul National University, Daehak-ro 101, Jongno-gu, Seoul 03080 South Korea.
authors.forename: Young-Kyun
authors.identifier: 0000-0002-7268-3870
authors.initials: YK
authors.lastname: Kim
keywords: Diameter; Outcome; Ultrawide implant