Characteristics of both patient and surgeon can affect dental implants’ success

Nov 7 2012

Characteristics of both patient and surgeon can affect the success of dental implants. A 10-year study finds that patient risk factors such as grinding teeth or diabetes increase the odds of implant failure. It also associates higher implant failure rates with surgeons who have less than 5 years of experience.

A study in a special issue of the Journal of Oral Implantology evaluated the success of 50 patients who received implant-supported fixed complete dentures. Encompassing a total of 297 implants, the retrospective study spanned 10 years, with a mean time of 3½ years from surgery to last follow-up.

The study examined failure rates for factors including type of prosthesis, surgeons' experience level, smoking, diabetes, bruxism, and implant location—maxillary or mandibular. The implant failures in this study appeared to be affected by patient risk factors, such as diabetes, rather than by implant-related factors, such as location and length of implant.

While smoking has often been shown to be a risk factor for implant failure, its effect was insignificant in this study. Bruxism (clenching and grinding of the teeth), most often during sleep, can affect bone loss and implant failure. Twenty-nine percent of patients with a dental history of bruxism in this study experienced implant failure. More than 28 percent of patients with diabetes suffered implant failure.

The number of years and surgeries performed by the oral surgeon also had an impact on the success of the implants, as did the complexity of the surgery required. Implants placed by surgeons who had previously performed less than 50 implants were twice as likely to fail. The failure rate was 12 percent among surgeons in this study with less than 5 years of experience.

Traditional implant guidelines requiring a healing period of 3 to 6 months before functional loading of dentures are giving way to immediate loading of a functional prosthesis. The success rates of these two methods are comparable, although this study found a slight advantage for the traditional approach.

An implant was considered successful if no implant loss occurred and bone loss was less than 4 mm as assessed by periapical radiograph. Overall, the study found a better than 90 percent absolute success rate for implant-supported fixed dentures and an 85 percent cumulative implant success rate.