| Abstract|| |
Computed tomography (CT) has been used in diagnosis and implant treatment, and CT can be used to assess the dimensional stability of graft materials after maxillary sinus augmentation. A 50-year-old male patient was treated for the simultaneous placement of implants with sinus augmentation and two post-operative CT scans were performed after the delivery of the prosthesis at 9 months and 15 months after the operation. There were no significant changes in alveolar bone height and the buccal window seemed to show remodeling over time. The continuity of the defect and the cortication were apparent in the 15-month post-operative CT scan. Implants installed simultaneously with sinus augmentation were well in function and the graft material seemed to be stable in maintaining tissue dimensions after the loading of the implants. The presented results need to be validated in further large case series or case-controlled studies.
Keywords: Computed tomography, dental implant, height, loading, sinus augmentation
|How to cite this article:|
Park JB. Radiographic follow-up evaluation of sinus augmentation with deproteinized bovine bone and implant installation after loading. Indian J Dent Res 2010;21:603-5
Maxillary sinus augmentation and placement of dental implants is a well-established technique for functional and esthetic dental rehabilitation of partially or completely edentulous patients with severe maxillary atrophy. 
|How to cite this URL:|
Park JB. Radiographic follow-up evaluation of sinus augmentation with deproteinized bovine bone and implant installation after loading. Indian J Dent Res [serial online] 2010 [cited 2013 May 25];21:603-5. Available from: http://www.ijdr.in/text.asp?2010/21/4/603/74227
Computed tomography (CT) provides a highly sophisticated format for precisely defining the jaw structure and locating critical anatomic structures,  and CT has been used in diagnosis and implant treatment. 
There have been a few publications using CT for evaluating the dimensional changes after the sinus augmentation, , but there are no published case reports evaluating the change in sinus-graft height after the delivery of the prosthesis. In this case report, two post-operative CT scans at the 9-and 15-month post-operative evaluations were used to evaluate the change of the dimension after implant loading.
| Case Report|| |
A 50-year-old male patient came for periodontal evaluation and treatment. The patient had a non-contributory medical history. The patient had the upper left 1 st and 2 nd molars missing. Sinus augmentation with simultaneous dental implant placement was planned and an informed consent was received.
Axial CT scans of the maxillary sinus region were performed before the surgery to evaluate the condition of the left maxillary sinus. The imaging was performed on a high-resolution CT scanner (SOMATOM sensation 4, Siemens, Germany) with a table progression of 2 mm. No pathology, including the thickening of the membrane, was observed in the left maxillary sinus [Figure 1] and the average remaining alveolar bone height was 6.0±1.4 mm [Table 1].
|Figure 1: Pre-operative cross-sectional view of the computed tomography scan|
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After infiltration with a local anesthetic agent, a crestal incision was made and the mucoperiosteum was elevated for exposure of the buccal wall of the maxillary sinus. A portion of the buccal wall was removed with generous saline irrigation. The exposed Schneiderian membrane was elevated to make space for the bone graft.
Preparation of the implant sites was carried out according to the protocol. A graft of deproteinized bovine bone mineral (Bio-Oss® ; spongious granule, particle size 0.25-1 mm; Geistlich Pharmaceutical, Wolhusen, Switzerland) was applied to the sinus floor. Two self-tapping, titanium implants with the sandblasted and acid-etched (SLA) surface (two 3.8×12 implants; Implantium, Dentium, Seoul, Korea) were inserted and the remaining sinus space was completely packed with bovine bone mineral. The defect in the buccal wall was then covered with an absorbable membrane (Bio-Gide® , Geistlich Pharma AG, Wolhusen, Switzerland) and the barrier membrane was stabilized with sutures. Antibiotic therapy with amoxicillin/clavulanic acid (three times per day) was continued for 5 days after the sinus augmentation procedure. The implants were exposed 4 months after implant placement and the final implant-supported crowns were inserted 7 months after the operation.
CT scans were performed within 1 week after the delivery of the final prosthesis to assess the new bone formation and the condition of the sinus membrane. The cross-sectional and panoramic views were used to measure the remaining alveolar bone and the change of the alveolar height [Figure 2]. Axial view was used to evaluate the cortication of the buccal defect in the maxillary sinus [Figure 3]. The implants were embedded in bone and bone was extended over the top of the implants. There was some irregularity on the buccal wall, and average alveolar ridge height at 9 months post-operatively was to be 11.9±0.6 mm [Table 1].
|Figure 2: A 9-month post-operative cross-sectional view of the computed tomography scan|
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|Figure 3: A 9-month post-operative axial view of the computed tomography scan showing some irregularities on the buccal wall of the maxillary sinus|
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An additional CT scan was obtained 15 months after the sinus augmentation, which is 6 months past the delivery of the permanent restoration. The grafted area appeared to be markedly denser than the autogenous bone [Figure 4]. The lateral wall of the former defect buccal window area seemed to be healed fully and the continuity of the bone was achieved [Figure 5]. The mean ridge height at 15 months post-operatively was 11.0±1.2 [Table 1]. The statistical analysis was carried out with SPSS 16.0 for Windows (SPSS Inc., Chicago, IL, USA) using the Wilcoxon signed ranks test. There were no statistically significant differences between the two evaluations performed at 9 and 15 months (P>0.05). The implant-supported prosthesis was functioning well up to 17 and the patient was scheduled for a follow-up visit [Figure 6].
|Figure 4: A 15-month post-operative cross-sectional view of the computed tomography scan|
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|Figure 5: A 15-month post-operative axial view of the computed tomography scan showing the continuity and the cortical of the buccal window|
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|Figure 6: Clinical view of the prosthesis in function at the final evaluation|
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| Discussion|| |
Volumetric changes have been evaluated using three-dimensional CT. , Wanschitz et al. reported that the average volume loss at 6.1±2.1 months was 13.9±1.9%.  Kirmeier et al. evaluated the dimensional stability for a longer period and showed that the mean volume shrinkage at 11 and 17 months of follow-up was 23.2% and 28.9%. 
However, there are no published case reports evaluating the change in sinus-graft height after the delivery of the prosthesis and, in this case report, two post-operative CT scans were used to evaluate the dimensional change after the delivery of the prosthesis. Two-dimensional CT was used to evaluate the alveolar bone height because it may be more suitable for determining the change of the graft height.  The axial scans were reformatted to produce radiographic sections through the implants in both the sagittal and the coronal directions, and the cross-sectional and panoramic views were used to measure the remaining alveolar bone.
There were no significant differences of alveolar bone height between the 9 and 15 month post-operative measurement, which suggests that the graft material may be stable in maintaining tissue dimensions after the loading of the implants. The change of buccal defect in the lateral wall was evaluated radiographically using the axial view. The remaining defect seen at the 9 th month was fully healed at 15 months and the cortication of the buccal window was seen. The resolution of the defect in the lateral wall may serve as an index for the healing state and remodeling of the graft material.
Implants installed simultaneously with sinus augmentation were well in function and the graft material seemed to be stable in maintaining tissue dimensions after the loading of the implants. The presented results need to be validated in further large case series or case-controlled studies.
| References|| |
|1.||Wanschitz F, Figl M, Wagner A, Rolf E. Measurement of volume changes after sinus floor augmentation with a phycogenic hydroxyapatite. Int J Oral Maxillofac Implants 2006;21:433-8. |
|2.||Garg AK, Vicari A. Radiographic modalities for diagnosis and treatment planning in implant dentistry. Implant Soc 1995;5:7-11. |
|3.||Ito K, Gomi Y, Sato S, Arai Y, Shinoda K. Clinical application of a new compact CT system to assess 3-D images for the preoperative treatment planning of implants in the posterior mandible. A case report. Clin Oral Implants Res 2001;12:539-42. |
|4.||Kirmeier R, Payer M, Wehrschuetz M, Jakse N, Platzer S, Lorenzoni M. Evaluation of three-dimensional changes after sinus floor augmentation with different grafting materials. Clin Oral Implants Res 2008;19:366-72. |
|5.||Szabo G, Suba Z, Hrabak K, Barabas J, Nemeth Z. Autogenous bone versus beta-tricalcium phosphate graft alone for bilateral sinus elevations (2- and 3-dimensional computed tomographic, histologic, and histomorphometric evaluations): Preliminary results. Int J Oral Maxillofac Implants 2001;16:681-92. |
Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]