title: Effects of Thread Depth in the Neck Area on Peri-Implant Hard and Soft Tissues: An Animal Study.
abstract: Implants with deep thread depth have been developed for the purpose of increasing total implant surface area. However, effects of implant thread depth remain controversial. The aim of this study is to examine effects of thread depth on peri-implant tissues in terms of bone-implant contact (BIC), bone-implant volume (BIV), and hard and soft tissue dimensions using comprehensive analyses, including microcomputed tomography (micro-CT).
  
  
  
  Five beagle dogs received experimental intramandibular implants 3 months after removal of their premolars and first molars (P2, P3, P4, and M1). Two different types of implants were installed in each animal: deep threaded (DT) and shallow threaded (ST). Resonance frequency testing was performed on the day of implantation as well as 4 and 8 weeks after implantation. Intraoral radiography, micro-CT, and histomorphometry were used to evaluate peri-implant tissues 4 and 8 weeks after implantation.
  
  
  
  There were no significant differences in resonance frequency test results between the two groups. Although radiographic analysis showed no group differences, micro-CT (P = 0.01) and histomorphometry (P = 0.003) revealed the DT group had significantly lower BIC values than the ST group at 4 weeks. However, by 8 weeks, BIC values of the two groups did not differ significantly. No significant differences in BIV or soft tissue height were observed between the two groups at either time point.
  
  
  
  DT implants showed no benefits over ST implants when inserted in dog mandibles.
authors.affiliation: Department of Periodontology, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
authors.forename: Shan-Pao
authors.initials: SP
authors.lastname: Sun
authors.affiliation: Department of Periodontology, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
authors.forename: Dong-Won
authors.initials: DW
authors.lastname: Lee
authors.affiliation: Department of Periodontology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, Republic of Korea.
authors.forename: Jeong-Ho
authors.initials: JH
authors.lastname: Yun
authors.affiliation: Department of Oral and Maxillofacial Surgery, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University.
authors.forename: Kwang-Ho
authors.initials: KH
authors.lastname: Park
authors.affiliation: MIR Dental Hospital, Daegu, Republic of Korea and MegaGen, Seoul, Republic of Korea.
authors.forename: Kwang-Bum
authors.initials: KB
authors.lastname: Park
authors.affiliation: Department of Periodontology, Gangnam Severance Dental Hospital, College of Dentistry, Yonsei University, Seoul, Republic of Korea.
authors.forename: Ik-Sang
authors.initials: IS
authors.lastname: Moon
mesh_terms: D000818:Animals; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D004285:Dogs; D020007:Implants, Experimental; D008334:Mandible; D016348:Osseointegration; D055114:X-Ray Microtomography
chemical_list: D015921:Dental Implants
keywords: Dental implants; dogs; histology; mandibles; osseointegration; osteogenesis