Frequent dental scaling might reduce infection risk after knee replacement
TAINAN, Taiwan: Oral bacteria that enter and spread through the bloodstream have been found to cause about 10 per cent of peri-prosthetic joint infections after total knee arthroplasty (TKA). Therefore, TKA patients are often advised to pay special attention to their oral health. A team of Asian researchers has now found that frequent dental scaling might reduce the risk of infection after TKA.
For patients with end-stage osteoarthritis, TKA is a common treatment to improve function and reduce knee pain. However, in some cases, patients contract subsequent peri-prosthetic joint infections. With a risk of about 2 per cent, these infections are the most frequent complication after TKA and may lead to functional loss, revision surgery and increased mortality.
In about one tenth of all cases, TKA infections are caused by oral bacteria that enter the bloodstream and cause transient bacteraemia, the temporary presence of bacteria in the blood. Oral bacteraemia may occur because of dental treatments, such as extractions or dental scaling, but also as a result of daily oral care, including toothbrushing and flossing. The condition has been found to occur more frequently in patients with poor oral health. Dental plaque accumulation and gingival inflammation in particular are thought to significantly increase the prevalence of bacteraemia after toothbrushing.
Regular dental scaling to remove plaque and calculus contributes to maintaining oral health and is provided by many dentists as part of routine dental care. Therefore, the researchers from National Cheng Kung University in Tainan hypothesised that it might be a possible way to reduce the risk of peri-prosthetic infection in TKA patients. In their study, the scientists investigated the association between the frequency of dental scaling and the risk of peri-prosthetic joint infection, using data from Taiwan’s National Health Insurance Research Database, which contains data on 99 per cent of the country’s population.
The researchers analysed 1,291 patients who had undergone TKA between 1999 and 2002 and needed revision surgery within five years after the initial operation owing to a peri-prosthetic infection. They compared these cases to a control group of age- and sex-matched TKA patients who had not had any peri-prosthetic infection.
The scientists found that the patients in the infection group had undergone less frequent dental scaling within the three-year period before their endoprostheses had to be removed. Of these patients, 73.1 per cent had not visited a dental clinic during that time to have dental check-ups and scaling, compared with 67.8 per cent in the control group. Only 7.1 per cent of the patients with a peri-prosthetic infection underwent regular dental scaling, whereas 10 per cent of the patients in the control group did.
Statistical analysis showed that patients who had received dental scaling one to four times during the three-year period had a 16 per cent lower risk of infection than patients who had not undergone the dental procedure. For patients who had seen the dentist five to six times for dental scaling, the risk was 31 per cent lower. The researchers concluded that regular dental scaling might reduce the risk of peri-prosthetic joint infection in TKA patients, as it can improve oral health and thereby reduce the risk of transient bacteraemia caused by oral bacteria. However, further research is required to confirm this connection, they stated.
The study, titled “Frequent dental scaling is associated with a reduced risk of periprosthetic infection following total knee arthroplasty: A nationwide population-based nested case–control study”, was published online in the PLOS ONE journal on 23 June.