The primary purpose of this study is to determine the local anesthetic efficacy and safety of 4% Articaine compared 2% Mepivicaine in 3 years old children, by using infiltration technique for primary teeth that required restorative, pulp therapy, or dental extraction procedure, as assessed by measuring the pain experience during injection and treatment procedures, child's behavior during the procedure, and postoperative complications.

Articaine has been widely used in dental surgery. Dentists started to use carticaine around 1977. In dentistry, articaine has been investigated extensively. Clinical trials comparing articaine mostly with lidocaine have varied in study design and site of action. The overwhelming majority of references in the literature describing the alleged neurotoxicity of articain concern paraesthesia and prolonged numbness after dental procedures. An excellent review of the dental literature was published last year. The authors concluded that articaine is a safe and effective local anesthetic drug to use in all aspects of clinical dentistry for patients of all ages, with properties comparable to other common local anesthetic agents. Although there may be controversy regarding its safety and advantages in comparison to other local anesthetics, there is no conclusive evidence demonstrating neurotoxicity or significantly superior anesthetic properties of articaine for dental procedures. The choice whether to use articaine or another local anesthetic is based on the personal preference and experiences of individual clinicians. 3Currently, articaine is available as a 4% solution containing 1:100,000 or 1:200,000 epinephrine. Clinical trials comparing 4% with 2% solutions show no clinical advantage of 4% over a 2% solution.

Inclusion criteria:

All patients have to meet all of the following inclusion criteria. They are eligible if:

1. They are Healthy (ASA 1: no acute or chronic disease, normal BMI percentile for age.

1. They are 36 to 47 months old children.
2. Intellectually qualified for communication.
3. They have under gone either clinically indicated gingival abscess, dental caries or pathological root resorption or periapical radiolucency showing on the radiograph.
4. Child's body weight at least 15 kg.
5. Ability to communicate effectively in the Arabic or English language.
6. Not taking any agents likely to interfere with reporting of pain (analgesics).
7. Needs any of the following procedure: Class I cavity, Class II cavity, pulpotomy, pulpectomy, stainless steel crown (SSC) or extraction.
8. Prior to enrollment, all radiographic data must be found acceptable by pediatric dentist.
9. Written and singed informed consent from legally acceptable representative.

Exclusion criteria:

Patients are excluded from the study if:

1. Patients have allergic to local anesthetic with epinephrine (sulphites or amide).
2. Intellectual or severe emotional problems. patient with intellectual development is significantly lower than average and his or her ability to adapt to the environment is consequently limited like autism, Down syndrome, fragile x syndrome, fetal alcohol syndrome, and Prader-Willi syndrome.
3. Considerable behavior problems.
4. Parents refuse participation in the trial.
5. History of previous bad dental experience.
6. Primary tooth who had a history of failed pulp therapy.
7. They have uncontrolled medical condition.
8. They use immunosuppressive agents, rifampin, or anticonvulsants, or any other medication.
9. Glucose 6 phosphate dehydrogenase deficiency.
10. Congenital cardiac diseases.
11. Seizures or uncontrolled epilepsy.