Non-surgical treatment of peri-implantitis, a randomized, single blind, controlled trial

Peri-implantitis is an inflammation of the peri-implant tissues with bleeding
and/or suppuration on gentle probing (<0.25N) with a blunt instrument and
crestal bone loss (Lang & Berglundh, 2011, Linde & Meyle, 2008). Swelling and
redness of the marginal tissues may or may not be present, and there is usually
no pain (Mombelli & Décaillet, 2011). In the worst case peri-implantitis may
lead to loss of the dental implant.
The prevalence of peri-implantitis in subjects with dental implant is 28-56%
(Zitzmann & Berglundh, 2008). With the increasing amount of dental implants,
the amount of subjects with peri-implantitis is rising. Evaluation of excisting
non-surgical treatment for peri-implantitis is therefore necessary (Renvert et
al., 2008).

Primary Objective:
To investigate the additional effect of systemic antibiotics (amoxicillin 375
mg and metronidazole 250 mg) for non-surgical treatment of peri-implantitis in
comparison to non-surgical treatment of peri-implantitis without the adjunctive
use of systemic antibiotics on the difference in clinical attachment level
(CAL) between baseline and three and twelve months.
Secondary Objective(s):
The secondary objectives are to investigate the additional effect of systemic
antibiotics (amoxicillin 375 mg and metronidazole 250 mg) for non-surgical
treatment of peri-implantitis in comparison to non-surgical treatment of
peri-implantitis without the adjunctive use of systemic antibiotics on the
differences in clinical (pocket probing depth (PPD), bleeding on probing (BoP),
plaque-accumulation and bone loss) and microbiological parameters between
baseline and three and twelve months.


In addition, the third objective is to compare the effect of systemic
antibiotics on the differences in clinical and microbiological parameters
between smokers and non-smokers and with the data of the periodontitis study
with the same non-surgical treatment protocol.

Before the baseline appointment a short summary of the research is given during
regular maintenance if the patient meets the inclusion criteria. When a patient
wants to participate an appointment voor an intake is made. During the intake
appointment an oral explanation of the study is given and the patient takes
home the written information letter.
The study procedures for this randomised controlled trial are explicated below.
Subsequent to the research protocol standard treatment procedures are
performed. Please see amendment 1 of the research protocol for the description
of the standard treatment protocol of peri-implantitis. Any diagnostic
procedures or treatments are not postponed. Clinical measurements and anamneses
are standard procedures during treatment appointments and will be adopted from
the electronic health record of the subject.

First visit: Baseline (BL) signed informed consent; plaque samples from the
deepest pocket of the target implant and from the deepest pockets of a natural
teeth (if present)
Randomization (R) blinded for the dentist

Second visit: (T1) dental hygiene instruction
First intake of antibiotics for the test group, blinded for the dental hygienist

Third visit: (T2) non-surgical treatment quadrant I and VI

Fourth visit: (T3) non-surgical treatment quadrant II and III

Fifth visit: (T4) dental prophylaxis, removing all the staining, calculus and
plaque

Sixth visit: (E1) evaluation, plaque samples

Seventh visit: (E2) evaluation after one year: plaque samples.

Non-surgical treatment (mechanical cleaning of the implant surface) of
peri-implantitis with adjunctive use of systemic antibiotics (amoxicillin 375mg
and metronidazole 250mg three times a day for 7 days).

The burden and risks in this study are not different when compared to standard
clinical treatment. The antibiotics used in this study are regularly used in
dental practices and may cause side effects.