The aim of the study is to assess the efficacy of a modified version of the behaviour management technique Latent inhibition in combination with Er:YAG laser for achieving reduction of dental anxiety in paediatric dental patients. The main objectives are to compare dental anxiety felt during the laser and conventional dental treatment. The outcomes will be dental anxiety assessment by a self-reported anxiety during treatment in both group as well as measurement of heart rate dynamics during the procedures.

When providing dental care to child patients with a high level of dental anxiety, the range of approaches are divided into two sections - use of behavior management techniques and application of alternative methods for caries removal. In attempt to reduce dental anxiety, they can be mixed and matched in accordance with the dentists' choice. Owing to the promoted advantages Er:YAG laser turns into an ideal alternative technique for hard dental tissue therapy in anxious pediatric patients.This is a protocol for a randomized controlled clinical trial. The participants will be children aged aged 6-12 years, requiring conservative treatment of occlusal carious lesions on a second primary molar. Patients will be randomly assigned to experimental or control group via computer-generated sequence. In both groups Latent inhibition will be used as an anxiety-management technique. In the experimental group caries treatment will be performed with Erbium:YAG laser, whereas in the control group with the conventional rotary instruments. Outcome measures will be dental anxiety felt before and after the treatment and the dynamics of heart rate, registered during the treatment session.

Inclusion Criteria:

1. Participants in the study are children aged 6-12 years, compliant with the cognitive development of the child and the requirement for complete root development;
2. Children, requiring conservative treatment of occlusal carious lesions on a second primary molar, without spontaneous unprovoked pain, percussion or palpation pain or other symptoms, indicating pulp involvement or periodontal pathology. Lesions are classified as distinct cavity with visible dentin without prior restoration or sealants by the International Caries Detection and Assessment System (ICDAS) with code 05. Included are caries lesions only on vital teeth.
3. Children with one or more permanent molars giving indications for pit and fissure sealing;
4. Patients without previous experience with laser treatment of carious lesions;
5. Children who are not considered medically compromised or medically complex patients;
6. Verbal assent from the child willing to comply with all study procedures and protocol;
7. Obtained written informed consent by the patient's parent/guardian for participation in the study

Exclusion Criteria:

1. Patients who were undergoing therapy with neurological, sedative, analgesic, and/or anti-inflammatory drugs 7 days prior to treatment that might affect heart rate;
2. Children, who were first-time dental patients;
3. Children with systemic diseases or physiological development delays;
4. Children with mental or cognitive problems;
5. Present infectious diseases such as influenza, scarlet fever, etc.
6. Excluded are molars which are affected by disturbances in the development of dental structures (hypoplasia, hypomineralization, fluorosis)

The randomisation will be independent and the patients and parents/guardians will remain blinded to group status.