Developmental defects of enamel (DDE) is currently one of the most prevalent conditions affecting children worldwide. Hypomineralized second primary molar (HSPM) is the current term being used for the condition previously described as deciduous molar hypomineralization. It is a qualitative developmental defect resulting from the disruption of enamel during formation. It usually presents as a clear demarcated opacity in the enamel translucency. This opacity may vary to several degrees from opaque white, yellow, to brown-colored lesion of enamel. Hypomineralized second primary molars have a clinical presentation similar to that of molar incisor hypomineralizaion. This may be due to a shared period of amelogenesis by second primary molars and first permanent molars. This condition is not just a related phenomenon to MIH but presents as a unique predictive factor for the occurrence of MIH. There is a likelihood of HSPMs being associated with post-eruptive breakdown and being more prone to caries. The hypomineralised enamel is a poor insulator and therefore, the pulp is not well protected from external thermal stimuli. As a result, the tooth becomes hypersensitive to hot and cold temperatures. This chronic stress on the pulp leads to an inflammatory response within the pulp and pH changes at periapical tissue level leading to hypersensitive pulp nerve tissue which excite with less stimulation than normally necessary. The clinical implication of this is a hypersensitive tooth that is difficult to anaesthetise even with increasing the local anaesthetic dose. There are several local anesthetics that can be used in children, the most common being: articaine 4% and lignocaine 2%. Although several studies have been published comparing lidocaine 2% to articaine 4% in children, results have been mixed. To date, there is no randomized clinical study comparing lidocaine with articaine when an inferior alveolar nerve block (IANB) is used for local anesthesia of HSPMs.