Prognose und Prognosefaktoren enossaler Implantate im bestrahlten Kiefer

Abstract

In comparison to tumor patients not receiving radiotherapy, the rehabilitation of masticatory function after head and neck irradiation is limited due to radiation-induced caries, radioxerostomia, and the risk of osteoradionecrosis. This study focused on implants in the irradiated jaw and on the evaluation of the prognosis and the effect of potential factors on the prognosis. The retrospective study covered 197 implants (47 patients) from 1988 to 1997. The implant prognosis was determined by implant survival statistics (Kaplan-Meier). Losses not related to the implants were censored. In addition, groups were formed according to factors potentially affecting the prognosis. The significance of differences in the groups relative to survival were tested using the log-rank test. Twelve (6.1%) implants from a total of 197 were lost due to peri-implantitis, and eight (4.1%) due to possible biomechanical stress. A total of 52 losses (26.4%) due to death of patients and two (1.0%) due to resection of the jaw were censored; 111 (56.3%) implants remained at recall and the average interval was 33 months. The rates of implant survival (Kaplan-Meier) after 1 and 2 years were 95%, after 3 and 4 years 92%, and after 5 and 6 years 72%. The univariate analysis of group comparisons showed a significantly lower rate of loss after perimplant flap reconstruction (p = 0.036). There was no effect due to the doses of irradiation (p = 0.16), chemotherapy (p = 0.90), or peri-implant osteoplasty (p = 0.84). Although none of the implants inserted before radiotherapy had to be explanted, the implant survival difference in the very heterogeneous groups was not significant (preirradiation, n = 29; postirradiation: n = 156; p = 0.13). According to the literature, the rate of survival of teeth which were sound before radiotherapy (1 year, 75%; 5 years, 45%) was distinctly lower than the survival of enossal implants (1 year, 95%; 5 years, 72%). The high-quality rehabilitation of masticatory function with implant-based protheses is the preferred method of treatment for irradiated tumor patients. In addition, contraindications for enossal implants were ruled out for all studied factors affecting prognosis.

Chronische Strahlenfolgen an den Zahnhartgeweben (“Strahlenkaries”) Klassifikation und Behandlungsansätze

“…Die engmaschige Kontrolle und Behandlung kann diese Zähne, die zur Abstüt-zung einer Teilprothese relativ gut geeignet sind, zumindest temporär über mehrere Jahre erhalten. Bei weitgehendem oder vollständigem Zahnverlust kann trotz Radioxerostomie die kaufunktionelle Versorgung durch dentale Implantate deutlich verbessert werden [13].…”

Long-term oral Candida colonization, mucositis and salivary function after head and neck radiotherapy

“…As a consequence, many different salivary functions are lost (antimicrobial, antiinflammatory, remineralization, lubrication, masticatory) [13]. This loss is the main factor limiting the achievement of oral rehabilitation after radiation therapy [14]. Although some patients seem to show slight recovery of salivary function, prospective longterm data on this problem are lacking.…”

Prospective study of the long term change of the oral flora after radiation therapy

“…Changes in oral pathogens are greatly affected by the changed saliva parameters as seen for radiotherapy as well as other non-radiotherapy reason. The increase of the cariogenic microflora in contrast to the nearly unaffected incidence of periodontopathogenic pathogens might explain the better long term survival of dental implants [28] compared to natural teeth [29] after radiotherapy. This requires broad efforts in the social and orofacial rehabilitation of oral cancer patients.…”