Risks and Performance of a New Guiding Device for Inferior Alveolar Nerve Block, EZ-Block ® , Compared to Traditional Free Hand Techniques: A Pilot Study

The conventional method of the inferior nerve requires the insertion of the near the of the where the inferior alveolar nerve is located before it the foramen. Some important intraoral landmarks need to be identified by the operator in the failure following of The general anatomical landmarks of the mandible that the be of and which can be used in the IANB, include the coronoid process and notch, the anterior and posterior border of the mandible, the sigmoid notch, and also the condyle. The most important clinical intra-oral landmarks used in the location of the IANB are the coronoid notch and the pterygomandibular raphe. The preferred site of needle insertion ABSTRACT Risks and Performance of a New Guiding Device for Inferior Alveolar Nerve Block, EZ-Block , Compared to Traditional Free Hand Techniques: A

lies between these two landmarks, and the point of insertion is determined by simple measurements: it is located on an imaginary line drawn from the deepest part of the pterygomandibular raphe to the coronoid notch.
The location of the insertion point on this line is one quarter the distance towards the pterygomandibular raphe above the occlusal plane of the lower teeth; the syringe barrel should be located at the opposite site close to the premolars teeth during injection [1,27].
The conventional IANB is associated with a failure rate of 15-20%, which represents the highest percentage of all clinical failures achieved using local anaesthesia [1,29]. Dunne [17] reported that the IANB was shown to have a success rate between 43% and 55.6% on healthy first permanent molar. Others studies that anaesthetised inflamed molar teeth, had success rates between 10% and 60% [17]. There are many reasons why the success rate of the IANB is low. One is that the dentist might make technique errors such as improperly locating a landmark or angling the syringe [32]. Other reason of failure IANB techniques is the high incidence of positive aspiration and intervascular injection, which counts for 10% to 15% [4].
Complication related to the IANB vary from being common to rare, and include pain and trismus produced by tearing the mucosa during the insertion or even the withdrawal of the needle, needle breakage at that point of injection, and facial paralysis caused by injection of the anesthetic solution in the parotid region: this problem mainly occurs when the needle is positioned more posterior towards the posterior border of the mandible. Hematoma may also develop due to the damage of blood vessels in the area to be anesthetized, as well as following the intravascular injection of anesthetic solution. Other reported complications include ptosis and extraocular muscles paralysis, aphonia, necrosis of the skin of the chin, diplopia, and abducent nerve palsy. Some rare complications include a reduction in visual acuity and atrophy of the optic nerve, diplopia (double vision), blurred vision, amaurosis (temporary blindness), mydriasis (papillary dilatation), abnormal pupillary light reflex, retrobulbar pain, miosis (papillary restriction), enophthalmos (recession of the eyeball within the orbit), and ophthalmoplegia (paralysis of muscles responsible for eye movement). It has been also reported recently that IANB could be a factor in third molar agenesis [1,12,13,30,32]. Ocular complications such as diplopia, loss of vision, or ophthalmoplegia are very rare [30]. Even though these symptoms tend to be temporary, they can be rather distressing to both patients and dental practitioners [13]. Most of the complications are localized and last for only a short period [30]. The guiding medical device EZ-Block ®, which relies on extra-oral landmarks easy to identify, would increase performance and reduce risks of IANB. To test this hypothesis, analysis of 32 articles  between 2000 and 2020 about risks and performance of IANB free hand techniques was made. These results were compared with those of a pilot study, carried out for a CE certification premarket study.

Clinical Data Sources Analysis
The research in the scientific literature was made with Pubmed,  "inferior alveolar nerve block" 2 "inferior alveolar nerve block" AND "benefits" 2 "inferior alveolar nerve block" AND "risks" 2 Clinicaltrials.gov "inferior alveolar nerve block" 56 (3 with clinical results)

Main criteria
To evaluate the performance: • Success rate with the rate of realization of the entire intervention.
• Onset time of 5 minutes with the number for patients.
To evaluate the benefice with the rate of reinjection.

Secondary objective
To evaluate: • The side effects associated with the use of the EZ-Block®; • The positive aspiration.

Secondary criteria
The side effects and the positive aspiration are evaluated in percentage (expected adverse effects: hematoma, trismus, Oedema, nerve injury).

Number of patients 139 patients
Main criteria for inclusion Any adult patient needing care or surgery on mandibular molar.

Exclusion criteria
Patients under 18 years, pregnant or breastfeeding women, allergies to the anesthesia molecule or to a component of the anesthetic cartridge, contraindications to the use of vasoconstrictors.  The success rate (