Marginal bone loss in relation to the implant neck surface: an update.

A review is made of the publications on the marginal bone loss of implants with a polished neck, rough neck with microthreading, and rough neck without microthreading. A PubMed search was carried out with the following key words: machined neck implant, polished neck implant, marginal bone loss, covering the period between January 1998 and March 2009. Inclusion was limited to those human clinical studies involving a minimum follow-up of 12 months, and registering the level of bone loss from the time of placement of the implant or prosthetic restoration to the end of follow-up. For most of the authors there were no significant differences in marginal bone loss between polished neck and rough neck implants. On the other hand, implants with a rough neck and microthreading showed significantly less bone loss than those with a polished neck or with a rough neck without microthreading. The survival rate of the implants with a polished neck ranged from 87% to 97.7%, versus 94.5% to 100% for those with a rough neck, and 100% for the rough neck implants with microthreading. No peri-implant disease was registered in the different studies.