Objectives

This practice-based cross-sectional study aimed at evaluating microbiological findings and aMMP-8 of periimplant mucositis (M) and periimplantitis (P) in partially edentulous patients under supportive implant therapy (SIP).

Methods

Patients

The present retrospective study includes the data of partially edentulous patients who were restored by a dentist in a private dental office between January 1, 1999 and June 30, 2006. Patients who met the following criteria were included:

• same type of implant (ANKYLOS, DENTSPLY Friadent, Mannheim, Germany)
• fixed superstructures
• participation in SIP
• functional period of the restoration >2 years

Dental examination

Dental examination covered pocket probing depth (PPD), bleeding on probing (BOP), and radiographic bone loss. Classification of periimplant diseases were derived:

• Mucositis (M): probing depth≥4mm+BOP
• Periimplantitis (P): probing depth ≥5mm+BOP/pus+ radiographic bone loss >3mm.

Different samples of gingival crevicular fluid (GCF) were taken from all periimplant pockets to detect periodontal pathogens (PCR), and aMMP-8 level (ELISA) at each implant side. Furthermore, saliva samples were collected for detecting the saliva aMMP-8-level.

Laboratory investigation

Microbiological analysis: Microbiological analysis of the periodontal pathogens at each implant side was carried out using polymerase chain reaction analysis (PCR; semi-quantitative detection; Micro-IDentplus-Test, Hain Lifescience, Nehren, Germany).

aMMP-8 analysis: The aMMP-8 level of each implant was determined by enzyme-linked immunosorbent assay (ELISA; quantitative aMMP-8-labory test, Dentognostics, Jena, Germany). The saliva aMMP-8 level of each patient was determined with a special saliva test by ELISA (Dentognostics, Jena, Germany).

Statistical analysis

For the statistical analysis Chi-Quadrat test and Kruskal-Wallis test were used; level of significance: α=5%.

Results

Patients (Tab. 1): 87 patients (57.1±11 years; f=51) with 168 implants (mean observational period: 68.2±24.8 months) were examined. The implant-related prevalence of M was 33% (n=55), and of P 9% (n=16).

Microbiological findings (Tab. 2): Microbiological analysis showed no statistical difference between M and P (p>0.05). Porphyromonas gingivalis (M: 67%, P: 68%), Tannerella forsythia (M: 58%, P: 62%), and Fusobacterium nucleatum (M: 89%, P: 93%) were the most frequent bacterial findings in both types of periimplant disease. Only Treponema denticola (Td), and Prevotella intermedia (Pi) showed a higher prevalence in P (M: Td=33%, Pi=25%; P: Td and Pi=50%).

aMMP8-8 findings (Fig. 1): The mean aMMP-8 level at implant sides showed no significant difference (p=0.05) between healthy (5.2±8.1), M (9.9±19.0), and P (4.9±7.7). Also, in saliva samples no statistical difference (p>0.05) between M (19.6 ng/ml; 95% CI: 14.7-24.5) and P (18.4 ng/ml; 95% CI: 14.5-22.3) was observed.

Conclusions

Microbiological findings and aMMP-8 level are not suitable for a predictable differentiation between periimplant mucositis and periimplantitis in patients under SIP.