Er:YAG Laser Versus Conventional Cavity Preparation in Children With Molar-Incisor Hypomineralization

This prospective, parallel-group, randomized clinical trial was conducted to compare the clinical effects of Er:YAG laser-assisted and conventional rotary cavity preparation in children with molar-incisor hypomineralization. Fifty-two children aged 6-12 years requiring restorative treatment of a mandibular first permanent molar were allocated in a 1:1 ratio to either the Er:YAG laser group or the conventional rotary instrument group.

In the laser group, cavity preparation was performed using an Er:YAG laser. In the conventional group, rotary instruments were used. Local anesthesia was not routinely administered but was provided when clinically required. Following cavity preparation, the teeth were restored using the same adhesive system and resin composite material in both groups.

Pain and behavioral responses were assessed using the Wong-Baker FACES Pain Rating Scale and the Face, Legs, Activity, Cry, Consolability scale. Dental anxiety was evaluated before and after treatment using the Modified Child Dental Anxiety Scale-Faces version. Heart rate and peripheral oxygen saturation were recorded as physiological indicators. Sensory experiences, overall discomfort, willingness to undergo the same procedure again, need for local anesthesia, cavity preparation time, and total procedure time were also recorded. Postoperative discomfort and the clinical performance of the restorations were evaluated at 1-, 3-, and 6-month follow-up visits.

Inclusion criteria

• Children aged 6 to 12 years.
• Diagnosis of molar-incisor hypomineralization according to the European Academy of Paediatric Dentistry diagnostic criteria.
• Presence of mild or moderate molar-incisor hypomineralization.
• Presence of an erupted mandibular first permanent molar (tooth 36 or 46) requiring restorative treatment.
• Presence of a single-surface occlusal carious lesion classified as ICDAS code 4 or 5.
• Vital target tooth without clinical or radiographic signs of pulpal or periapical pathology.
• No previous restorative treatment of the target tooth.
• Cooperative behavior corresponding to Frankl behavior rating scores 3 or 4 and Venham scores 0 to 2.
• Written informed consent provided by a parent or legal guardian.
• Child assent to participate in the study.

Exclusion criteria

• Presence of a systemic or neurodevelopmental condition that could affect pain perception, anxiety, communication, or cooperation.
• Use of analgesic, anxiolytic, sedative, or other medication that could influence pain or anxiety assessment before treatment.
• Presence of spontaneous dental pain, irreversible pulpitis, pulp necrosis, or periapical pathology in the target tooth.
• Requirement for multisurface cavity preparation or extensive restorative treatment.
• Previous restorative treatment of the target tooth.
• Inability of the child or parent/legal guardian to understand or complete the study assessments.
• Refusal of the child or parent/legal guardian to participate.