Effectiveness of buffered local anesthetic solutions in pediatric nerve blocks and infiltration anesthesia: a systematic review and meta-analysis

Local anesthesia is essential for pain control and behavioral management in pediatric dentistry. Conventional anesthetic solutions often have low pH, causing injection discomfort and delayed onset. Buffering local anesthetics, typically with sodium bicarbonate, may enhance efficacy by increasing the pH, reducing injection pain, and accelerating onset. This study aimed to evaluate the clinical efficacy of buffered and unbuffered local anesthetic agents in pediatric dental patients, with an emphasis on the onset of anesthesia, patient-reported pain perception (subjective pain), and clinician-assessed pain responses (objective pain) during injection. A systematic literature search was conducted using PubMed, ScienceDirect, the Cochrane Library, LILACS, and Google Scholar for studies published between January 2000 and March 2025. Only randomized controlled trials (RCTs) specifically focused on pediatric patients aged 4-12 years comparing buffered and unbuffered local anesthetics were included. The risk of bias of the included studies was assessed using the Cochrane Risk of Bias 2.0 (ROB 2) tool. Meta-analyses using a random-effects model with standardized mean differences (SMD) accounted for variability across studies. The review protocol was prospectively registered with PROSPERO (CRD420251051999). Of the 138 records initially identified through the literature search, five RCTs met the eligibility criteria and were included. When compared with unbuffered solutions, buffered local anesthetics demonstrated a promising trend toward faster onset and reduced subjective pain. Meta-analysis revealed a significant reduction in subjective pain scores with buffered agents (SMD = -0.59, 95% CI: -1 to -0.17, P 2 = 66%), whereas pooled effects on anesthesia onset (SMD = -1.55, 95% CI: -3.67 to 0.57, I2 = 97%) and objective pain (SMD = -0.53, 95% CI: -1.2 to 0.15, I2 = 82%) were not statistically significant. Risk of bias assessment indicated three low-risk studies, one with some concerns, and one high-risk study suggesting a cautious interpretation of the findings. Buffered local anesthetics reduced injection pain, accelerated the onset of pediatric dental procedures, and enhanced patient comfort. Objective pain outcomes are less consistent, but buffering is a promising and cost-effective adjunct to improve clinical experience. Nevertheless, additional high-quality RCTs with standardized protocols are recommended for additional evidence.