The effect of adjusting the pH of local anaesthetics in dentistry: a systematic review and meta-analysis.

The acidic nature of commercial local anaesthetics (LAs) can cause pain during infiltration and delay the onset of anaesthesia. It is suggested that adjusting the pH of anaesthetic agents could minimize these effects. This systematic review aimed to evaluate the efficacy of buffered LAs in reducing infiltration pain and onset time during dental procedures. MEDLINE, Embase, Scopus and Scielo databases were searched up to April 2017. Randomized controlled trials comparing buffered and unbuffered LAs for intraoral injections were included. Risk of bias was assessed using the Cochrane Collaboration tool. Data upon injection pain and onset time were pooled in a random-effects model. Subgroup analyses compared normal and inflamed tissues, and terminal infiltrations and inferior alveolar nerve (IAN) blocks. Meta-regressions were performed to explain heterogeneity. Fourteen articles were included in this review. Lidocaine with epinephrine was the most used anaesthetic combination. Nonlidocaine studies (n = 2) were not pooled in the meta-analysis. Buffered lidocaine did not result in less pain during intraoral injections: mean difference -6.4 (95% CI -12.81 to 0.01) units in a 0-100 scale. Alkalinized lidocaine did not reduce the onset time in normal tissues when terminal infiltration techniques were used, but resulted in a more rapid onset for IAN blocks (-1.26 min) and in inflamed tissues (-1.37 min); however, this change may not be clinically relevant, considering the time required to prepare the buffered agent. Studies performed using other anaesthetic salts did not show robust and clinically significant results in favour of alkalinization.

Cardiovascular responses to different stages of restorative dental treatment unaffected by local anaesthetic type.

BACKGROUND: The aim of this study was to evaluate the cardiovascular effects of maxillary infiltration using 2% lidocaine with 1:100,000 adrenaline, 4% articaine with 1:200,000 adrenaline, and 4% articaine with 1:100,000 adrenaline in different stages during restorative dental procedures. METHODS: Twenty healthy patients randomly received 1.8 mL of the three local anaesthetics. Systolic blood pressure, average blood pressure, diastolic blood pressure, and heart rate were evaluated by the oscillometric and photoplethysmograph methods in seven stages during the appointment. RESULTS: Statistical analysis by ANOVA and Tukey tests of cardiovascular parameters did not show significant differences between the anaesthetic associations. There were significant differences for the parameters among different clinical stages. CONCLUSIONS: The variation of cardiovascular parameters was similar for lidocaine and articaine with both adrenaline concentrations and showed no advantage of one drug over the other. Cardiovascular parameters were influenced by the stages of the dental procedures, which showed the effect of anxiety during restorative dental treatment.