This multicentre, randomized clinical trial compared digital intraosseous anaesthesia with conventional local anaesthetic techniques in children aged 6-12 years receiving restorative treatment for MIH-affected permanent first molars. Within the maxillary stratum, digital intraosseous anaesthesia was compared with conventional infiltration anaesthesia; within the mandibular stratum, it was compared with inferior alveolar nerve block. The primary outcome was child-reported pain during restorative treatment. Secondary outcomes included pain during needle penetration and anaesthetic solution delivery, observed pain-related behaviour, and change in dental anxiety.