Title

A new landmark and modification of the standard inferior alveolar nerve block injection

Lead Author Affiliation

Dental Surgery Program

Second Author Affiliation

Dental Surgery Program

Third Author Affiliation

Dental Surgery Program

Fourth Author Affiliation

Biomedical Sciences

Introduction/Context

Nerve block anesthesia is employed to serially block the inferior alveolar (IA), mylohyoid, and lingual nerves. Success rates range broadly (13-98%). To improve IA success rates we test a new landmark that is stable and consistently visible in the oral cavity. Here we: 1) test the ability of the landmark to guide needle placement, 2) test different mandibular opening positions, and 3) identify anatomical variations that impact needle placement.

Method

We CT scanned a geographically diverse sample of adult skulls (n=26). The dentition varies from complete to edentulous, with M3/3 erupted or unerupted. Virtual mandibles were duplicated. Condylar heads of one model were aligned for maximum opening (~40-45mm) with translation; the other slightly closed (~30-35mm) without translation. Oblique orthoslices through the interproximal surfaces of the LP3-4 and the maxillopterygoid junction mimics the injection pathway. The coronoid notch set injection height.

Results

Assessment of the maxillopterygoid junction as a landmark for insertion shows the needles path terminates just superior to the mandibular foramen in 73% of cases (19/26: maximum opening/positioned on eminence). In 19.2% of cases (5/26), the plane terminated near or just posterior to the ramus. Neither geographic variation nor the presence/absence of the M3/3’s impacted this relationship

Significance/Conclusions

Use of this technique holds the potential to greatly simplify IA blocks. However, the reasons for the observed variation in needle termination are currently obscure. Clarifying relationships between landmarks employed in block procedures and anatomy relevant to achieving anesthesia should lead to more standardized, patient-centered techniques and improved success rates.

Comments

This work was supported by funding previously obtained from Dr. Richards. This work was presented at the ASDA District 11 meeting in Irvine, CA in October, 2015 and San Francisco Dental Society Meeting Poster Presentation on March 2, 2016.

Location

University of the Pacific, Dugoni Dental School, San Francisco, CA

Format

Poster

Poster Session

Senior Research Presentations

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A new landmark and modification of the standard inferior alveolar nerve block injection

University of the Pacific, Dugoni Dental School, San Francisco, CA

Nerve block anesthesia is employed to serially block the inferior alveolar (IA), mylohyoid, and lingual nerves. Success rates range broadly (13-98%). To improve IA success rates we test a new landmark that is stable and consistently visible in the oral cavity. Here we: 1) test the ability of the landmark to guide needle placement, 2) test different mandibular opening positions, and 3) identify anatomical variations that impact needle placement.