Er:YAG Laser for Dental Cavity Preparation

The goal of this clinical trial is to compare Er:YAG laser cavity preparation with conventional rotary instruments in adults who have permanent premolars planned for extraction as part of orthodontic treatment. The main questions the study aims to answer are: How do Er:YAG laser and conventional rotary instruments compare in the time needed for cavity preparation? Do participants experience different levels of pain with the two methods? Which cavity preparation method do participants prefer after experiencing both methods? Are there differences in cavity surface and interface characteristics and microleakage between teeth prepared with the two methods? Researchers will compare Er:YAG laser cavity preparation with conventional rotary cavity preparation using a split-mouth design. Each participant will receive both treatment methods on two different eligible permanent premolars. Participants will: Have one eligible premolar prepared with an Er:YAG laser and another eligible premolar prepared with conventional rotary instruments. Have the two procedures performed at separate visits on different days. Rate their pain after each procedure and indicate which treatment method they would prefer for future dental treatment. Have the study teeth extracted approximately 1 month later, as already planned for their orthodontic treatment. After extraction, the teeth will be examined in the laboratory to compare cavity surface and interface characteristics and microleakage between the two preparation methods.

Inclusion Criteria: * Adult participants with permanent maxillary or mandibular premolars scheduled for extraction for orthodontic reasons. * Eligible premolars are intact or have carious lesions limited to the enamel and are free of pain symptoms. * Where carious lesions are present, teeth meet the study eligibility criteria based on ICDAS II 2009, as specified in the study protocol. * Participants voluntarily agree to participate and provide informed consent. * No spontaneous or continuous dental pain. * Clinical examination, thermal pulp testing, and electric pulp testing are consistent with normal pulp status. * Radiographic examination shows no periapical radiolucency and complete root apex formation. * Participants have no systemic health condition that could adversely affect healing. Exclusion Criteria: * Participants with psychological or behavioral conditions that prevent adequate cooperation with the study procedures. * Teeth showing radiographic evidence of internal root resorption or pulp canal calcification.