To find the mean distance of the maxillary posterior tooth apices to the sinus, and the lateral thickness of adjacent bone over these apices.
- N= 12 autopsy and 38 live pts (medical CT previously prescribed) exclusion of patients with craniofacial trauma, deformity, etc.
- CT scan measurements compared to macroscopic autopsy measurements (no significant difference found). Protrusion into the sinus given a negative value. Contralateral teeth averaged for each tooth type.
- An inverse relationship exists between the thickness of bone BL and bone thickness superior to the apices of the teeth.
- Apices furthest from sinus floor is of the first premolar (6-7 mm) getting progressively closer in more posterior teeth (second molar 0.5- 2 mm).
- Buccal roots lie under 1- 4 mm buccal bone.
- Palatal roots lie under 1- 3 mm palatal bone, except 1st premolar (5.5 mm).
- Distances from sinus floor will dictate the size of the crypt during surgical endodontics.
- Lateral thickness of bone may indicate location of access with consideration of soft tissue reflection, hemorrhage control, and visibility.