Review - ZZI 01/2010

Indication of a preoperative antibiotic prophylaxis
for insertion of dental implants – A systematic review

B. Al-Nawas1, K. Stein2

The aim of this study was to review the available literature on the question of whether preoperative antibiotic prophylaxis during implant placement reduces the risk of implant failure in patients without general medical risk factors.

The literature search was done using the medical databases Pubmed, Medpilot and the Cochrane Library. A hand-search was performed in dental journals. The studies were selected using a systematic quality evaluation and a meta-analysis.

Eight studies fulfilled the inclusion criteria: neither of the two studies of evidence level I showed a significant difference in the early implant failure rate between the test and the control groups. The studies of evidence level II also showed only a minor positive effect of antibiotic prophylaxis. We performed an aggregation of the data of the prospective clinical studies with control groups, which naturally must be interpreted with appropriate caution as there was marked heterogeneity between the four studies. There, a statistically significant difference between the intervention and control groups was apparent, with antibiotic prophylaxis having a clearly positive effect on the early implant failure rate with a number needed to treat of 56.

Based on the present available evidence of “moderate quality”, a “weak recommendation” can be given for antibiotic prophylaxis with a penicillin during implant placement.

Keywords: systematic review; meta-analysis; early failure; antibiotic prophylaxis; implant insertion

Introduction

For decades, dental patients have been managed very successfully with oral endosseous implants. An important strategy to increase the success rate is avoidance of (early) infection. This raises the question as to whether routine preoperative antibiotic prophylaxis prior to placement of endosseous implants in patients without medical risk factors reduces the number of early failures. This question continues to be controversial among dental professionals and in the literature [5, 7, 10, 15, 22, 29]. In view of the risk of potential side effects and the dangerous growth in the number of resistant microorganisms [11], a responsible decision on whether or not antibiotics are indicated should be based in part on the findings of high-quality studies (external evidence). It should not be forgotten that evidence-based medicine (EBM) does not mean being guided only by this external evidence. Besides the external evidence, the individual dentist’s experience (internal evidence) and the patient’s preference are also important. The fact that these factors can only function jointly as a “tool” is often overlooked when EBM is discussed. All three factors are particularly important in the question of the effectiveness of antibiotic prophylaxis.

A systematic review is a scientific study in which relevant studies (external evidence) are identified, their quality is evaluated and their results are summarized according to scientific methods [17, 21]. Besides a traceable search according to clearly defined criteria, evaluation of the quality of the literature represents a very important element of a systematic review. The importance that can be attached to the result of a study depends on whether attention was paid during the planning and conduct of the study to various factors that can distort the result of the study (“bias“) [21]. An accurate presentation of the study conditions therefore plays a major role. Authors and journal editors should be guided by the CONSORT statement in the presentation and publication of clinical studies [23]; this provides a practical checklist for producing manuscripts.

Since the “assignment of patients” to the different treatment arms (test vs. control) in a study can be a great source of error, this question is of major importance. For instance, in one study of perioperative antibiotic prophylaxis, patients having “difficult” operations might be assigned more often to the antibiotic prophylaxis arm by the study investigator or by the patients themselves. Randomization, i.e. random assignment of the study participants to the intervention and control groups, is intended to guarantee that the participants are balanced with regard to known and unknown influencing factors. Accordingly, randomization can take place only in a study with a prospective design with a control arm and this is regarded as desirable with regard to the evidence gained.

Ordering external evidence in a hierarchy according to such criteria of validity has become accepted. The classification in Table 1a refers to the fundamental suitability of a study design for arriving at valid results by avoiding systematic errors [28]. It is clear that clinical studies do not always fit into this relatively rigid system. This is why the clearly laid out GRADE system (Table 1b) has recently come to be preferred [12, 13].

The search, therefore, was always for the best available (external) evidence, which does not absolutely have to be a randomized study but can also be based on observational studies. It is therefore surprising that randomized studies on the subject of “Antibiotic prophylaxis with implant insertion” exclusively are considered in the Cochrane Review [10]. In the version of 2003, which was the occasion for this study, it was even concluded that there was no evidence at all for or against antibiotic prophylaxis [8]. This is a result that hardly assists the clinician in decision-making.

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