Background: Local anesthesia (LA) during routine dental treatment in children fails in 5%-35% of first attempts. No data, however, are available on the success rates of subsequent attempts. Aim: To evaluate the effectiveness of primary, secondary, and tertiary LA attempts (P-LA, S-LA, and T-LA, respectively) for anesthetizing molars during routine dental treatments in children. Design: We retrospectively analyzed dental records of all children (2-18 years) who had been administered LA for the treatment of primary or permanent molars by a single paediatric dentist, between 2011 and 2022. All LAs were delivered using a computer-controlled local anesthetic delivery (CCLAD) system. Results: The failure rate of P-LA in 1312 molars was 13% and correlated with age (p < .001), type of tooth (p < .001), type of treatment (p < .001), and treated arch (p < .001). The effectiveness of S-LA for buccal infiltration, intrasulcular, inferior alveolar nerve block, greater palatine nerve block (GPNB), posterior superior alveolar nerve block (PSANB), or a combination of the last two was 50%, 87.2%, 66.7%, 63.6%, 33.3%, and 100%, respectively, and was not significantly associated with age or the type of tooth, treatment, or P-LA. Conclusion: The optimal choice of S-LA for anesthetizing maxillary molars was a combination of PSANB and GPNB, whereas for mandibular molars, it was IS-CCLAD system.
