Efficacy of Repeated Locoregional Anesthetics Blocks With Bupivacaine in Patients Suffering of Chronic Dentoalveolar Pain.

The aim of this study is to evaluate the efficacy of anesthetic blocks repeated with bupivacaine in the management of patients with persistent dentoalveolar pain. Goals are to improve the understanding of the physiopathological mechanisms of persistent dentoalveolar pain and to highlight predictive criteria for the effectiveness of anesthetic blocks.

This is a proof of concept, randomized, controlled prospective pharmacological trial, single blind, with two parallel arms.

The main objective of the study is to evaluate the efficacy of repeated locoregional anesthetic blocks with bupivacaine in patient's persistent dentoalveolar pain compared to a control group receives a simulated anesthesia (local anesthesia with lidocaine).

The secondary objectives are :

* to evaluate the tolerance of repeated locoregional anesthetic blocks to bupivacaine patients with persistent dentoalveolar pain compared to control receiving simulated anesthesia (local anesthesia with lidocaine).
* to evaluate demographic and nosological predictive factors (age of symptoms, Quantitative Sensory Testing results) and psychometric (anxiety, depression, dramatization) of the effectiveness of anesthetic blocks.

After signing the informed consent, the patients participate will be randomized to anesthetic block treatment with bupivacaine or lidocaine.

During the 1st step of the study patients will participate at 6 visits (day -7, day 0, day 7, day 14, day 21 and M2) and will receive either a series of 4 locoregional anesthetic blocks with bupivacaine or a series of 4 local anesthesia with lidocaine ("simulated" control group) at day 0, day 7, day 14 and day 21. The main criterion is raised 2 months after the end of the series.

During the 2nd step

* The patients from experimental group will be followed until month 6 (2 visits: month 3 month 6).
* The patients from control group :
* will received in open (if they want) a series of 4 locoregional anesthetic blocks with bupivacaine (day56, day,63, day 70, day 77) and will be followed during 6 months after the first injection (7 visits: day 63, day 70, day 77, month 3, month 4, month 5, month 8)
* will be followed until month 6 ((2 visits: month 3 month 6).

Eligibility Criteria:
Inclusion Criteria:

* Patient, male or female, over 18, with persistent dentoalveolar pain defined according to the criteria:

  * daily presence (\> 2 hours / day and for more than 3 months) and continues pain;
  * located at one or more teeth or at the level of the alveolar bone;
  * not following a nervous path;
  * clinical, radiological and neurological examinations showing no cause organic visible;
  * dental causes excluded by appropriate tests;
  * local or systemic pathologies related to pain apart.
* Pain intensity greater than or equal to 4/10 on numerical scale
* Patient informed of the constraints of the study and having given his written consent. Benefiting of a social security scheme.
* Mastering correctly French.

Exclusion Criteria:

* Pregnant women, breastfeeding, or likely to be pregnant.
* Oral pain of known origin (cancerous, infectious, traumatic).
* Patient having modified (stopped, started or modified dosage) in the last 2 month local or systemic medication that may interfere with the study results (for example, patients taking long-range psychotropic drugs will not be excluded).
* All medical pathology judged by the investigator as not compatible with the study.
* Known hypersensitivity to local amide-bound anesthetics or to any of the excipients
* Treatment anticoagulant or known disorder of blood
* Porphyria.
* Atrioventricular conduction requiring training permanent electrosystol not yet realized.
* Epilepsy not controlled by a treatment.
* Patient non-cooperating, not speaking or not reading fluently French or in the impossibility of understanding the principle of a pain scale or understanding the study or to sign an informed consent.
* Patient under guardianship, curatorship, or deprived of liberties.