The use of antibiotic prophylaxis in implant dentistry : a microbiological and clinical perspective

The current development of antibiotic resistance calls for prudent use of antibiotic prescription. Methods of investigating antibiotic overconsumption, include identifying areas of misuse or overuse, as well as implementing recommendations and guidelines. The efficacy of antibiotic prophylaxis prior to dental implant surgery is debated. However, the rationale for restrictive antibiotic prophylaxis is often based on tradition rather than actual knowledge of negative consequences. Therefore, the general aim of this thesis is to investigate the rationale for restrictive antibiotic prophylaxis in implant dentistry and to determine actual prescription behavior. Study I: The aim of Study I was to investigate the microbiological consequences on oral microflora in terms of selection for resistance extent, and to determine the ecological disturbance after a single dose of 2 g amoxicillin. Thirty-three healthy participants were given a single dose of 2 g amoxicillin. Saliva was collected prior to administration of antibiotics (day 1), and on days 2, 5, 10, 17 and 24. A large ecological disturbance among oral aerobic microflora was observed. The proportion of viridians streptococci with reduced susceptibility to amoxicillin was significantly increased on days 2 and 5 (P = 0.00 and P = 0.04, respectively). Study II: The aim of Study II was to investigate antibiotic prophylaxis prescription behaviors among dentists placing dental implants, and to check the influence of scientific reviews published in 2010. Questionnaires were distributed during two time periods (2008 and 2012). The questionnaires were sent to eligible dentists (120 in 2008, 161 in 2012) in the Stockholm region, Sweden. In 2008, 88% of the dentists routinely prescribed antibiotic prophylaxis during implant surgical procedures, while in 2012 this dropped to 74% (P = 0.01). There was a significant change in dentists’ prescription patterns with 65% prescribing a single dose prophylaxis in 2012, compared to 49% in 2008 (P = 0.04). Study III: The aim of Study III was to investigate the effect of antibiotics on the outcome of bone augmentation in conjunction with dental implant placement. This was a complex systematic review combining the recommended quality assessment methods for systematic reviews and primary studies. Selected primary studies were reviewed using a protocol for assessment of randomized studies, while scientific evidence was graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) (Balshem, et al. 2011). The results showed that no relevant systematic reviews pertaining to the topic of this study where found. For primary studies, only two studies were regarded as a moderate risk of bias. Study IV: The aim of Study IV was to determine antibiotic prescription behavior among dentists performing bone-augmentation procedures prior to, or in conjunction with dental implant surgery, and to check the influence of national recommendations published in 2012. In addition, this study also investigated the occurrence of postoperative infection following these bone-augmentation procedures. A multi-center retrospective study was performed. Four hundred patients’ medical charts were investigated during two time periods (2010-2011 and 2014-2015). The results showed that, on comparing the two time periods, there was a significant reduction in the number of patients treated according to national recommendations (P = 0.02). Moreover, a significant reduction in the duration of antibiotic treatment was also seen (P = 0.03). The number of patients not given antibiotic prophylaxis significantly increased (p = 0.00). In addition, the rate of postoperative infections was low and without significant difference between both time points (3.5% in 2010-2011 and 7% in 2014-2015). In conclusion, single dose of prophylactic antibiotics induces a significant selection of resistant strains among oral microflora and causes a large ecological disturbance. There is a wide variation in the type, dose and duration of prophylactic antibiotic treatment prior to simple or complicated implant surgery. Knowledge regarding the use of antibiotic prophylaxis for reducing the risk of infection with bone augmentation procedure in conjunction with dental implant placement is lacking. The results of these four studies support a restrictive approach to antibiotic prophylaxis and warrant a thorough revisiting of indications for antibiotic prophylaxis. In addition, safety aspects pertaining to refraining from single antibiotic use need to be fully investigated. There is a need for strict guidelines based on solid scientific evidence to promote the rationale for antibiotic usage