It is a single-center, prospective clinical study of a medical device, controlled, randomized, non-stratified, double-blind (neither the patient nor the parents know which area is irradiated / practitioner who performs the measures and evaluates the class I achievement or non also ignores the irradiated area) .

Children included in this clinical trial will be their own control, an area receiving LASER irradiation the other receiving a simulation LASER irradiation (placebo side, inactive laser) .

In the maxilla, it will be segmented using a technique by the introduction of sectional side (portion of elgiloy arch supporting molars, canines and premolars) which serve as a support for Intermaxillary Strength II (or Intermaxillary Elastics II).

The patient should put his own Intermaxillary Elastics II, force adapted to the amount of class II dental, and this 24h/24. The patient should position him/herself these intermaxillary elastics in the first mandibular molar to the maxillary canine ; their action, in case of maximum mandibular anchorage, is to reduce maxillary canine in order to obtain reports of class I. In the mandible, a maximum anchor will be realized. Maximum molar anchor is to place the roots of mandibular molars in the vestibular cortex in order to anchor them there. This allows the lower canines, premolars and maxillary molars under the action of FIM without causing mutual advancement of the mandibular arch.

This procedure does not differ from the usual treatment. The application of laser diode appears, by biomodulatrice action, to show promising results on accelerating the kinetics of tooth movement during orthodontic treatment. The main hypothesis of the research is an increase in the rate of correction of Class II irradiated side, i.e. a 1-month shortest delay in obtaining the class I for irradiated areas vs. non irradiated ones.

The main objective of this study is to evaluate the effect of the application of low energy laser (LLLT) on the time required to obtain a Class I canine on patients undergoing FIM II (Class II elastics)

Pre-inclusion criteria:

Written consent of parental authority, ie if any of the two parents, will be required, but the apparent unwillingness of the child shall prevail if any.

No exclusion period is required if the child has already attended another biomedical research.

Inclusion criteria:

• With a Class II canine complete or partial, bilateral and symmetrical

• In permanent dentition (no deciduous teeth in the arch)

• Requiring the use of intermaxillary strength (FIM) II correction dental class II during a multi fasteners orthodontic treatment

• Leveling done beforehand*

• Anchor of the mandible is maximum

  • The same technique employed should be segmented in the maxilla, in all patients (lateral sectional canine to molar).

Exclusion Criteria:

Patient :

• having a mental deficiency or child who can not read or write (difficulties in completing the questionnaire )
• with lack of cooperation (withdrawal, refuse to wear FIM II)
• who missed at least 3 consecutive appointments according to the medical record ,
• with orofacial malignant tumor
• having unbalanced chronic diseases or patient receiving treatment that can interfere with orthodontic treatment or with pain assessment (antibiotics, analgesics, treatment of bone and mineral metabolism, diabetes, hormonal treatments excluding contraceptives)
• with a Class II dental unilateral and asymmetric
• with a dental anomaly from shape and / or structure related to the following teeth: maxillary canines and first molars causing an increased risk of detachment brackets
• with anomalies of number : agenesis of permanent teeth
• with a mixed dentition
• refusing to give consent or with one or two parents refusing to give their consent (for minor patients)
• participating in another biomedical research
• pregnant