195 CT scans from a private practice were examined. Measurements were made with computer software (Simplant) at 5mm intervals. Patients were categorized as to age, sex, and missing posterior teeth.
The following data emerged at the 95% confidence level (Excerpted from Table 1):
Distance from the crest to the inferior alveolar nerve at the first molar:
In males with no missing teeth : 13.85mm
In females with no missing teeth : 12.50mm
In males with missing posterior teeth: 10.20mm
In females with missing posterior teeth: 8.96mm
Other measured variables were available bone volume from the alveolar nerve to the inferior border of the mandible, the buccal cortex and the lingual cortex.
A high degree of variability in mandibular bone volume surrounding the inferior alveolar nerve. Greater risk of injury for females. CT scan should be considered when limited bone above the nerve is observed in conventional radiographs.
Dr GebrAel’s comments:
A must read (and re-read) article giving helpful average measurements as they relate to implant placement in the posterior mandible.
For more information PLEASE Refer To:
Radiographic Considerations for the Regional Anatomy in the Posterior Mandible
Natasha Yashar, Christopher G. Engeland, Alan L. Rosenfeld, Timothy P. Walsh, Joseph P. Califano
Journal Of Periodontology Jan 2012, Vol. 83, No.1, Pages 36-42