A comparison of teeth and implants during maintenance therapy in terms of the number of disease-free years and costs - an in vivo internal control study


  • Conflict of interest and source of funding statement:

    The authors declare that they do not have any conflict of interest.

    The study is self funded by the authors.


Øystein Fardal

Kvednabekkvn 4

N-4370 Egersund


E-mail: fardal@odont.uio.no



Little is known about the cost minimization and cost effectiveness involved in maintaining teeth and implants for patients treated for periodontal disease.

Materials & Methods

A retrospective study was carried out encompassing all patients who had initial periodontal treatment followed by implant placement and maintenance therapy in a specialist practice in Norway. The neighbouring tooth and the contra-lateral tooth were used as controls. The number of disease-free years and the extra cost over and above maintenance treatment for both teeth and implants were recorded.


The sample consisted of 43 patients with an average age of 67.4 years. The patients had 847 teeth at the initial examination and received 119 implants. Two implants were removed 13 and 22 years after insertion. The prevalence of peri-implantitis was 53.5% at the patient level and 31.1% at the implant level. The prevalence of periodontitis was 53.4% at the patient level and 7.6% at the tooth level. The mean number of disease-free years was: implants: 8.66; neighbouring tooth: 9.08; contra-lateral teeth: 9.93. These mean values were not statistically significantly different from each other. The extra cost of maintaining the implants was about five times higher for implants than for teeth.


The number of disease-free years was the same for neighbouring teeth, contra-lateral teeth and implants. However, due to the high prevalence of peri-implantitis, the cost of maintaining implants was much higher than the cost of maintaining teeth.