Endosseous implants are used in the treatment of various types of tooth loss, and numerous long-term studies have demonstrated the excellent reliability of this method of treatment. However, the increase of implant failure are associated with inadequate quality and/or height of bone. At the end of the 1980s, Wide(>3.75mm) implants were initially used for managing these difficult bone situations. The recommended indications for its use included poor bone quality, inadequate bone height, immediate placement in fresh extraction sockets, and immediate replacement of failed implants. At the 2000s, wider implants(6.0mm and 6.5mm) were used in a few studies. Although good clinical outcomes have been reported in recent years, there is still a controversy on this topic.

Therefore, the purpose of this study was to estimate the survival rate of wide implants(6.0~8.0mm) in molar regions, evaluating the clinical outcome.

In this study, 1135 RBM surfaced wide implants(Rescue™, MEGAZEN Co., Korea/ 595 maxillary, 540 mandibular) were placed in 650 patients(403 male, 247 female/age mean: 51.2±11.1 years, range 20 to 83 years). Of the total, 68.3% were used to treat fully or partially edentulous situations, including single-tooth losses and 31.7% were placed immediately after teeth extraction or removal of failed implants, of which all were in the molar regions. Implant diameter and length ranged from 6.0 to 8.0mm and from 5.0 to 10.0mm, respectively. The implants were followed for up to 42 months (mean: 14.6±9.5 months).

Of 1135 placed implants, 58 implants were lost. Among them, 53 implants were lost within 12 months after implant placement. The survival rate was 93.6% in the maxilla and 96.3% in the mandible, yielding an overall survival rate of 94.9%, for up to 42 months. As the result of Cox regression model, prosthetic type, sinus graft, and patient gender have an statistical significance on the implant survival rate in this study.

This study suggests that the use of wide implants(6.0~8.0mm) would provide a predictable treatment alternative in posterior areas.