Thesis (M.D.S. 1979) from the Department of Oral Pathology and Oral Surgery, University of Adelaide.

The location of mental nerve has been extensively studied anatomically and radiographically. This systematic review aims to summarize the common location of mental foramen (MF) as well as its anatomical variation, the accessory mental foramen (AMF). The PubMed and Google Scholar databases were both searched for the available study until Jan 2020. The database search yield 2766 study of which 47 were included in this study according to the inclusion criteria. The study concludes that in general the position of the mental foramen is between area distal to the first premolar root apex and the long axis of the apex of second premolar in 82% to 90% according to panoramic and CBCT studies reported until 2020 respectively. Importantly, AMF incident has been found in 8.3% of the population, according the all of the CBCT studies included in this systematic review.

INTRODUCTION: Many studies have used different diagnostic methods to detect and measure the mental loop. Due to different criteria used and dissimilar diagnostic techniques diverse results were found in these studies. Understanding anatomical structures are crucial for planning and placing dental implants. Implant surgeons should be familiar with anatomical variations that they may encounter. METHODS: CBCTs of twenty male and twenty female patients were selected and categorized into four groups; male and female groups aged (18-44) and male and female groups aged (45-65). SIMPLANT Pro 17.01 software was used to determine the shape and the extension of the mental loop. Data was collected and analyzed for statistical significance to determine the association between CBCT findings and the patient's gender and age. RESULTS: The extension of the anterior loop of the metal nerve in this study ranged between 0 – 3.17mm. The mean of the loop was 1.25mm. The mental loops mean extension in males was 1.25mm. The mental loops mean extension in females was 1.23mm. The mental loops mean extension in elders was 1.19mm. The mental loops mean extension in younger group was 1.28mm. Subjects tend to have more curved mental loops compared to straight loops regardless the gender and/ or age group. CONCLUSION: In this study no association found between the shape and the extension of the mental loop with subjects age and gender. Measuring the extension of the mental loop should be mandatory for each individual to avoid injuries during implant placement in the interforaminal region.