Buffering of Local anaesthesia (LA) has been suggested as a mechanism to improve injection comfort and hasten the onset of anaesthesia. Aim This study aimed to evaluate the effectiveness of buffered LA in the extraction of maxillary premolars and molars. Materials and Methods This randomized controlled study included 100 patients who were indicated for extraction of maxillary posterior teeth, they were randomly divided into two groups; a study group that received infiltration of buffered 2% lidocaine hydrochloride with 1:80,000 epinephrine LA, and a control group that received non-buffered 2% lidocaine hydrochloride with 1:80,000 epinephrine LA. The buffering was performed using the Onset® LA buffering system (Onpharma®). The outcome variables included the pain during injection buccally and palatally assessed by pain Numerical rating scale, the onset of anaesthesia, the volume of local anaesthesia used, and the patient satisfaction for the whole procedure. Results There were statistically significant differences in pain during injection buccally and palatally in favour of the study group (p < 0.0001) with a large effect size for the palatal injection and moderate effect size for the buccal injection. The onset of anaesthesia on the buccal and palatal sides was significantly faster in the study group (p values 0.02 and 0.01, respectively). There was a non-significant difference between the groups with respect to the volume of anaesthesia (p = 0.07). The patients in the study group reported a significantly higher satisfaction score (p < 0.0001). Conclusions Buffered LA significantly reduced the onset of action of anaesthesia and pain during injection, especially on the palatal side, and resulted in better satisfaction with the extraction procedure.
