PMC3680989_01
Preoperative intraoral findings.. 
a: Upper dentition (occlusal view).. 
b: Lower dentition (occlusal view).. 
c: Front teeth (front view).. 
d: Left-side view of molar occlusal status. Planned implant site indicated with an asterisk (*).
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In 2005, the patient returned, and requested implant treatment to replace the bridge (Fig. 1). 
Alveolar bone findings.. 
a: Appearance of the alveolar bone sample.. 
b: 3D-microCT image of the longitudinal section, through the center of the sample.. 
c: Hematoxylin-eosin staining of the same section as in (b).
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 Using a trephine bur, an alveolar bone sample (column-shaped; 2 mm in diameter, 7 mm in height) was obtained from the implant site (Fig. 2a), before the the implant was placed (5 mm in diameter, 13 mm in height, Branemark system , Nobel Biocare, Gothenburg, Sweden). After fixation, the fine trabecular structures of the sample were observed with microCT (Fig. 2b), at the following settings: slice thickness 20 microm; magnification 4.58X; 80.0 kV and 76 microA (ELE SCAN; Nittetsu. Tokyo, Japan). The sample was then decalcified, embedded in paraffin and sliced into thin sections for hematoxylin-eosin staining (Fig. 2c) and tartrate-resistant acid phosphatase (TRAP) staining.
Preoperative radiographic findings.. 
a: Periapical radiographof the planned implant site. Arrowheads indicate the borders of an irregularly-shaped radiolucency.. 
b: Panoramic radiograph, with an irregularly-shaped radiolucency (arrowheads) also visible.
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The panoramic and periapical radiographs revealed an irregularly-shaped radiolucency under the alveolar crest at the planned implant site (Fig. 3), and the trabeculae were not clearly visible with ordinary CT (Fig. 4).
3D-microCT images of the alveolar biopsy sample.. Left to right: microCT images, with the sample being successively rotated approx. 60 degrees clockwise each time.. CB: cortical bone; TB: plate-like trabeculae.
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MicroCT three-dimensional (3D) images of the bone sample clearly showed several plate-like trabeculae extending outward from the lingual cortical bone (Fig. 5).
Histological findings.(a) to (d) Hematoxylin-eosin staining of paraffin sections. (e) and (f) TRAP staining of paraffin sections.. 
a: Adipose tissue, visible over a wide range in the marrow space.. 
b: Hematopoietic cells, occasionally visible in certain areas of the marrow.. 
c: Several flattened osteoblasts (fOb), visible at the bone surface.. 
d: Cuboidal osteoblasts (cOb), occasionally visible at the bone surface.. 
e: TRAP-positive bone surface, indicated by the red staining at the bone surface.. 
f: A few TRAP-positive osteoclasts, on the resorption lacuna.
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Histological observations revealed that the marrow space was filled with adipose tissue (Fig. 6a), and that most of the bone surface was covered with flattened osteoblasts (Figs. 6a, c). However, some hematopoietic cells were observed in the bone marrow (Fig. 6b), and cuboidal osteoblasts were also seen on the bone surface in a few regions (Fig. 6d). TRAP-positive osteoclasts and cement lines were also observed (Figs. 6e, f). The histomophometricdata are shown in Table 2.
Radiographic findings, two years post-operatively.. 
a: Periapical radiograph of planned implant site.. 
b: Panoramic radiograph.. Although a radiolucent area is still visible around the center of the implant, bone is also visible directly adjacent to the implant.
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