Optimal anesthesia is an essential requirement for successful dentoalveolar intervention.To achieve this goal,different anesthetic agents and techniques are available. Inferior alveolar nerve block (IANB) remains the most commonly used anesthetic technique. However, after the worldwide approval of articaine, a relatively new local anesthetic with enhanced tissue diffusion properties, many studies on healthy volunteers have investigated the anesthetic efficacy of buccal articaine infiltration and IANB in the mandibular posterior teeth and reported comparable results. Infiltration anesthesia is technically more straightforward, less stressful to the patient, and associated with higher success and lower complication rates than block anesthesia. The aim of this study was to determine the effectiveness of local infiltration anesthesia using 4% articaine in the analgesia of deciduous and permanent molars in children aged 5-18 years and mandibular premolars in children aged 10-18 years.

Clinical study to evaluate the effectiveness of local anesthesia with 4% articaine in order to ensure painless and effective implementation of dental procedures in children. Selection of respondents: participians with good systemic health - patients classified as American Society of Anesthesiologists (ASA) classification - ASA I and ASA II will be included in the study and required invasive dental treatment using local anesthetic (restoration or extraction) on deciduous and permanent molars in children aged 5-18 years and mandibular premolars in children aged 10-18 years, over 20 kg of body weight.The research would include at least 60 participials aged 5-18, who would be divided into two groups. One group the local anesthetic 4% articaine would be used. The second group would be provided with the local anesthetic 2% lidocaine chloride, as a control group. Analysis and data collection in each group would create subgroups depending on the age of the participials: 5-9 years, 10-13 years and 14-18 years.A clinical study would be doubly blind. Participials who would be included in the clinical study would sign a consent form to participate in the clinical study but would not know which anesthetic would be received.Criteria for measuring efficacy would be to measure pain during anesthetic injection,10 minutes after injection, and during and after the intervention using:

1. Visual Analog Scales (VAS)
2. Tooth vitality test
3. Wong-Baker Pain Rating Scale (W-BFSR)
4. Frank Behavior Rating Scale (FBRS)
5. By determining the growth and development of the roots of permanent premolars and molars
6. By determining the resorption of the roots of deciduous molars.

The child's behavior would be monitored through all phases of clinical work by direct observation of the dentist(examiner) who is in charge of measuring the effectiveness of anesthetics but does not know what type of anesthetic. Only a dentist who applies(practitioner) an anesthetic will know what type of anesthetic it is. After that, the examiner would fill in the questionnaire based on the answer of the child / parent (guardian).

In accordance with known ethical principles and in accordance with the principles of Good Clinical Practice (GCP), care for the well-being of the patients was maximally respected, in accordance with the latest revision of the Declaration of Helsinki and accepted principles that apply to clinical trials on humans. The holder of the protection of the patients in this clinical trial is the principal researcher, who cooperated with the Ethics Committee of the Dental Clinic of Vojvodina, University of Novi Sad. The patients written Informed Consent implied that the patient had received full information about the research, and was stressed that they had the right to decide independently to participate, without coercion and external influences, or any harmful consequences if they refused to participate.

Inclusion Criteria:

• Respondents of both sexes, aged 5-18 years
• Subjects in need of either conservative rehabilitation or tooth extraction on deciduous or permanent premolars and / or molars
• Subjects who have an X-ray of the teeth for the need of dental rehabilitation

Exclusion Criteria:

• difficult cooperation with the patient
• existence of allergy to local anesthetic
• the existence of a diagnosed general disease
• unsigned informative consent

Patients were randomly and equally assigned to treatment groups. The study was planned as a double-blind. Thus, neither the patients nor the researchers knew which anesthetic will be applied. Only practioner, who will injected anesthetic will know what tipe of anesthetic is it - 4% articain or 2% lidocain chlorid. Number of participials is 60, divided into two equal groups.