Safety of local anaesthesia in dental patients taking oral anticoagulants: is it still controversial?

The aim of this study was to investigate the safety of local infiltration techniques and the inferior alveolar nerve block (IANB) in dental patients taking oral anticoagulants. A total of 352 patients were given a total of 560 injections of local anaesthetic (119 IANB and 441 others). The study group comprised 279 patients with therapeutic international normalised ratios (INRs), and the control group 73 patients who were taking oral anticoagulants but had subtherapeutic INR on the day of operation. Blood was aspirated 7 times (7.3%) during the IANB in the study group. However, there were no clinical signs of prolonged haemorrhage into the medial pterygoid muscle or pterygomandibular space after 96 IANB, including those from whom blood had been aspirated. Only two minor haematomas developed after multiple infiltrations in the lingual sulci. The results suggest that bleeding as a result of the use of local anaesthesia in patients with therapeutic INR is unlikely, provided that the IANB is done correctly.