The Maxillary Sinus Floor Elevation Using a Poly-L-Lactic Acid Device to Create Space Without Bone Graft: Case Series Study of Five Patients
Maxillary sinus floor elevation using autologous or alloplastic bone grafting is often performed for implant treatment of maxillary molars; however, issues related to the donor site and complications such as infection have been reported. We performed maxillary sinus floor elevation using poly-L-lactic acid (PLLA) as a space-making material in patients with an insufficient bone mass (<3 mm) for simultaneous implantation between the alveolar crest and floor of the maxillary sinus and evaluated the newly formed bone. Conventional antrostomy of the maxillary sinus from the lateral wall was performed, and PLLA was placed on the floor of the maxillary sinus after elevating the sinus membrane. Six months after surgery, the bone mass and density were measured using quantitative computed tomography, and histological evaluation was performed. No complications were recorded. Radiological findings showed a bone-like radiopaque appearance, and histological examination revealed new bone formation in all patients. In cases with insufficient bone mass prior to simultaneous implant placement, this method of maxillary sinus augmentation allows for sufficient bone augmentation without bone grafting.
Figure 1. Material used: 0.3-mm-thick hydroxyapatite 40% poly-L-lactic acid (PLLA) mesh plate. Figure 2. (a) Antrostomy and elevation of the maxillary sinus membrane. (b) Schematic diagram showing the method of placement of PLLA.
Figure 3. X-rays show implants in place before superstructure. (a) Case 3. (b) Case 4. Figure 4. Invagination of soft tissue into the antrostomy site.
Measurement of the increase in bone thickness. The increase in bone thickness was measured using computerized tomography images. (a) Preoperative. (b) Six months postoperative, poly-L-lactic acid mesh plate (arrows).
(a) Bone surface stained red, indicating active progression of bone formation. Connective tissue is seen in the central portion of the specimen. (b) Hematoxylin and eosin staining showing the presence of prebone and a large number of osteoblasts arranged in a well-aligned pattern, indicating active progression of bone formation. There is no inflammatory infiltration of lymphocytes, and loose connective tissue and a large number of new blood vessels are observed. (c) Goldner staining showing bone formation sites that are not yet noncalcified (stained red), indicating that bone formation is still active.
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