Effect of staged crestal maxillary sinus augmentation: A case series

Abstract

Background: In sinus augmentation, when remaining bone height is ≤5 mm, a lateral window approach is often the preferred choice; nonetheless, patients prefer to have a less invasive approach such as crestal sinus augmentation (CSA). Prior case reports have described the use of various staged approaches of a CSA technique in cases of limited bone height. The aim of this report was to describe the results of a case series in which a two-stage CSA technique was used in patients with 4 to 6 mm of bone height.

Methods: Nineteen subjects with 28 sinuses of initial vertical bone height of 4 to 6 mm were included in which a two-stage CSA technique was used in place of a lateral window approach. In the first surgery, 0.3 mL graft material was inserted into all sites. In the second surgery, 13 sites were filled with 0.2 mL graft material and remaining 15 sites were filled with 0.4 mL.

Results: No damage was observed in the maxillary sinus floor membrane after first 0.2 mL filling; however, one case had Schneiderian membrane perforation after filling 0.4 mL. The average elevation height (EH) after first surgery was 5.81 ± 0.7 mm, 5.15 ± 0.91 mm before second surgery, 6.69 ± 0.89 mm with 0.2 mL filling (total 0.5 mL) and 8.11 ± 1.24 mm with 0.4 mL filling (total 0.7 mL). The thickness of maxillary sinus membrane before first surgery was 2.6 ± 2.59 mm; however, it has become 0.97 ± 1.59 mm before second surgery, with a decrease of 1.6 mm estimate.

Conclusion: This case series that assessed outcomes of staged crestal maxillary sinus augmentation was an effective approach to elevating 6 or 8 mm alveolar bone height without causing major membrane perforation. However, the two-stage approach was used in the limited residual bone height (4 to 6 mm) and required two separate surgical procedures.

Keywords: Schneiderian membrane; crestal sinus augmentation; crestal sinus lift; internal sinus lift.

Figure 1

New bone regeneration after the first and the second surgery of CSA procedure. (A) The vertical height of bone formation. (B) Bone formation measured at the buccal–palatal (BP) dimension. (C) Bone formation measured at the medial–distal (MD) dimension. (D) and (E) show the method used to measure needed data. Vertical height (VH) was measured from the crestal bone to the grafted bone at the midline saggital plane. At the same plane, buccal–palatal (BP) bone was measured at the meeting point of grafted bone and the buccal and palatal limits of the sinus. Medial–distal (MD) bone formation was measured at the most grafted bone shown on the coronal plane

Figure 2

Comparison of the bone formation between the first and the second surgery during the CSA procedure. (A) Vertical bone height (VH), (B) buccal–palatal (BP) bone height, (C) mesial‐distal (MD) bone height, and (D) changes of the sinus membrane thickness (MT) at the first and the second surgery. *P < 0.05 analyzed by t‐test

Figure 3

A representative clinical case. (A) Preoperative CBCT shows a crestal bone height of <5 mm. CSA was indicated. (B) The first surgery was performed after osteotome, 0.3 mL grafting material (a mixture of HA and osteogen) inserted into the sinus without elevating the sinus membrane. (C) Follow‐up CBCT of 42 days after the first surgery shows new bone regeneration at the grafted area. (D) Second surgery was performed 1 week later. At first 0.2 mL new grafting material (DFDBA) was inserted after osteotome procedure, then 0.4 mL grafting material was added before implant placement (E). (F) 4.7 × 12 mm implant was placed at the same second surgery after second bone grafting at the sinus. (G) six‐years follow‐up shows a minimum bone resorption after implant placement after CSA. X shows images in sagittal plane, while Y shows images in coronal plane. Magnification of images in green is available in the next figure

Figure 4

High magnification of images A, F, and G in Figure 3. The crestal bone height before CSA procedure was 4.3 mm. Sinus membrane thickness was 1.4 mm (A). After implant placement, crestal bone height including implant and underneath newly formed tissue is 14.8 mm. The newly formed tissue including newly regenerated bone is 2.5 mm (B). In 6‐year 10 months follow‐up (C), the newly formed tissue is 2.6 mm. X shows images in sagittal plane, while Y shows images in coronal plane

Figure 5

Diagram illustrating the surgical steps of CSA. (A) Step 1. Osteotome followed by sinus augmentation with the first grafting material (HA mixed with osteogen with high contrast). (B) Follow‐up right before the second surgery. (C) Step 2. Second surgery is performed by inserting the second amount of grafting material (DFDBA without high contrast) after osteotome. Implant placement is simultaneously performed