Cross-sectional Examination of the Reliability of Oral Implants
Conditions: Periimplantitis
Sponsor: German Association of Oral Implantology e. V.

STUDY PROTOCOL 
 
Cross-sectional examination for the certainty of success of oral implants 
 
F. Schwarz 
 
Poliklinik for Dental Surgery and Admission, West German Kieferklinik, 
Heinrich Heine University, Düsseldorf 
 
Correspondence address: Prof. Dr. Frank Schwarz 
Polyclinic for Dental Surgery 
Heinrich Heine University 
Moorenstrasse 5 
40225 Düsseldorf 
Germany 
Tel: (+) 49 211 81 04471 
Fax: (+) 49 211 81 04474 
Email: Frank.Schwarz@med.uni-duesseldorf.de 
 
 
1. Aim of the study 
The aim of the present multi-centre, cross-sectional study is to determine 
the prevalence and incidence of mucositis and peri-implantitis. 
Furthermore, with the help of a cytokine analysis of peri-implant swab 
samples and of blood lymphocytes or monocytes on titanium platelets and 
particles in vitro, the tolerance of titanium in relation to the clinical 
conditions will be examined. In total, a maximum of 200 patients will be 
examined at 10 centers over a period of 6 months using clinical, genetic 
and microbiological parameters. 
 
2. Material and methods 
200 patients will be enrolled in the study at a maximum of 10 centers (20 
patients per center) that have been presented for a routine check-up. The 
centers are 3 university clinics, a hospital and 6 private practices: 
 
• Clinic for Periodontology at the University of Bern 
• Polyclinic for Dental Surgery and admission to Heinrich Heine University 
Düsseldorf 
• Clinic for Maxillofacial Surgery at the Georg-August University in 
Göttingen 
• Clinic for maxillofacial surgery at the Red Cross Hospital Kassel 
• Private dental practice Dr. Karl-Ludwig Ackermann / Filderstadt 
• Private dental practice Dr. Gerhard Iglhaut / Memmingen 
• Private dental practice Prof. Dr. Werner Lill / Vienna, Austria 
• Private dental practice Dr. Ralf Rössler / Wetzlar 
• Private dental practice Dr. Michael Stimmelmayr / Cham 
• Private dental practice PD Dr. Ata Anil / Bitburg 
 
Titanium implants had been placed in all of the test subjects in the 
individual centers within the last 10 years. After the implantation, they 
were included in a regular recall system. All test subjects are informed in 
detail about the course of the study both verbally and in writing and give 
their written consent. At any point in time, the patient has the option of 
leaving the examination. The study protocol is checked by the ethics 
committees of the medical faculties of Heinrich Heine University in 
Düsseldorf, Georg-August University in Göttingen, Ludwig Maximilian 
University in Munich and the University of Bern. 
 
3. Inclusion criteria for patients 
• Presence of at least one helical dental implant made of cp-Ti with an 
insertion date after April 1st, 2001 
• No other titanium implants in the body 

• Regular participation in a recall 
 
4. Course of studies 
 
4.1 General medical history 
As part of the survey of the general anamnesis, the underlying internal 
diseases of all patients are recorded. In particular, questions are asked 
whether the patient has diabetes mellitus, whether bisphosphonates or 
acetylsalicylic acid are regularly taken and whether there are allergies. 
In addition, the patients' smoking habits are asked about. 
 
4.2 Clinical investigation parameters 
For patients with multiple implants, a maximum of two implants are 
examined, the most clinically noticeable and one normal implant. All 
measurements are carried out by a previously calibrated person using a PCP 
12 periodontal probe (Hu-Friedy kal, Germany). 
The following clinical parameters are determined: 
 
 
Plaque Index (according to O’Leary): 
Determination in each case on the gingival margin to record the cleaning 
success in 6 places around the implant (mesio-facial, mid-facial, disto-
facial, mesio-oral, mid-oral, disto-oral). There is no staining test. 
 
Bleeding on probing (BOP): 
Determination 30 seconds after probing at 6 points around the implant 
(mesio-facial, mid-facial, disto-facial, mesio-oral, mid-oral, disto-oral) 
to determine the peri-implant inflammation status. 
 
Probing depths (ST): 
measured at 6 places around the implant as a distance: marginal mucosal 
edge - pocket floor (mesio-facial, mid-facial, disto-facial, mesio-oral, 
mid-oral, disto-oral). 
 
 
4.3 X-ray diagnostics 
    
An x-ray image, preferably a dental film, is made for all patients as part 
of a routine diagnosis. In individual cases, an orthopantomogram can also 
be made. These are compared with the X-ray images already available at the 
time the prosthetic superstructure was incorporated and an assessment of 
the peri-implant bone is carried out. 
 
4.4 blood test 
A blood sample (fresh heparinized blood) is taken from each patient, with 
which a lymphocyte activation test is carried out in vitro. For this 
purpose, the samples are sent overnight to the Prof. Thomas Center / LMU 
Munich. There, lymphocytes and monocytes are isolated from the samples and 
incubated in vitro with titanium particles and on titanium plates from 
Astra, Camlog, Dentsply, Nobel Biocare and Straumann. After several days of 
culture, the release of inflammatory cytokines is measured (IL-1, IL-6, IL-
8, interferon , TNF, TNF, MMPs, etc.). Furthermore, a DNA bank for 
further polymorphism studies is created from a small additional sample and 
the CRP, beta crosslaps and HbA1c values are measured from the serum sample 
obtained. 
    
 
4.5 IL-1 polymorphism analysis 
With the help of a brush (GenoType® PST® plus, Hain Lifescience GmbH, 
Nehren), a smear is also taken in the peri-implant area. The brushes are 
then placed in a test tube and examined in the laboratory for an IL-1 
polymorphism (Bioscientia GmbH, Ingelheim). 

 
 
4.6 Microbiological test parameters 
A microbiological examination is carried out on all patients. For this 
purpose, the qualitative and quantitative presence of Aggregatibacter 
actenomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella 
intermedia (Pi), Tannerella forsythia (Tf), Treponema denticola is 
determined with a marker germ analysis (micro-IDent® plus, Hain Lifescience 
GmbH, Nehren) (Td), Peptostreptococcus micros (Pm), Fusobacterium nucleatum 
(Fn), Campylobacter rectus (Cr), Eubacterium nodatum (En), Eikenella 
corrodens (Ec) and Capnocytophaga sp. (C.sp.) examined. For this purpose, 
after the examination area has dried, a sterile paper tip is inserted to 
the bottom of the respective peri-implant pocket and left there for about 
20 seconds. These are then placed in a test tube and examined in a 
laboratory (Bioscientia GmbH, Ingelheim). 
 
 
4.7. Quantitative determination of the protein aMMP-8 
Furthermore, a quantitative determination of the tissue-degrading protein 
aMMP-8 is carried out in all patients (Bioscientia GmbH, Ingelheim). 
 
 
5. Evaluation 
Based on the clinical and radiological findings, the prevalence of 
mucositis and peri-implantitis in all patients is statistically recorded 
with the software program ImpDat (Kea GmbH, Pöcking). In addition, it is 
checked whether there is a correlation between the occurrence of peri-
implant inflammation and the genetic, immunological and microbial factors 
also recorded.