In the present biopsy sample, the cortical cap was more than 3 times as wide in the anterior mandible as in the corresponding segment of the maxilla (Table 1). The reason for this difference is most likely explained by the pre-extraction status of the alveolar process. Thus, in the anterior region of the mandible, the spongy tissue in the facial and lingual bone wall is often absent (Arau ́ jo et al. 2008). In such locations, the facial and lingual cortical plates are continuous with the alveolar bone proper (of the socket). During healing following tooth extraction, the two cortical plates may fuse, hereby establishing a prominent cortical cap in the symphysis region. This kind of hard tissue was by Lekholm & Zarb (1985) denoted “Quality 1” bone and was considered to provide ideal conditions for primary stability of an endos- seous implant following installation. The validity of this hypothesis was questioned in a study by Cecchinato et al. (2012) who found a positive correlation between the volume of bone marrow (Quality 4 bone) in the recipient site and degree of osseointegra- tion.