Bone formation after sinus augmentation with engineered bone

Objectives: The aim of the following investigation was to quantify the resorption rate of tissue-engineered bone grafts in the maxillary sinus using volume measurements. MATERIAL AND METHODS: Sinus floor augmentation using autologous bone grafts from the iliac crest (n=17, group 1) was compared with commercially produced transplants of human cells seeded on polyglycolid-polylactid (PLGA) scaffolds (Oral Bone) (n=14, group 2). RESULTS: The total resorption rate for autologous transplants 3 months post operation was 29%, while the tissue-engineered bone showed a resorption rate of 90%. The autologous bone had a bone density of up to 266-551 Hounsfield units (HU), while sufficient mineralization of tissue-engineered bone was found in only one case (152 HU). CONCLUSION: In this clinical study, the use of autologous cancellous bone grafts in sinus augmentation was more reliable than scaffolds containing cultured osteoblasts. Further tissue-engineered bone transplants should be examined to draw general conclusions about the use of tissue-engineered grafts compared with autologous bone grafts for maxillary sinus augmentation.     

DBBM骨替代材料在上颌窦外提升中的三维影像学研究

目的：通过螺旋CT数据的三维重建与测量,评估用含量为100% DBBM无机牛骨(Bio-Oss)充填材料进行上颌窦提升后提升区组织的体积稳定性。方法：对12例用100% DBBM进行上颌窦外提升一期植骨术的患者分别于术后2周与6个月行提升区的螺旋CT扫描,将CT数据通过SurgiCase CMF5.0软件进行三维重建与测量,通过自身前后对照观察充填区体积的变化。数据计算由Stata10软件包完成。结果：充填物总体积平均减小19.40%。其中,颊腭向最宽处平均减少0.29%,近远中向最宽处平均减少5.87%,垂直向最高处平均减少14.32%。结论：DBBM在术后6个月内有一定的体积收缩,以垂直向最为显著。     

Bone reformation with sinus membrane elevation: a new surgical technique for maxillary sinus floor augmentation

Background: Various maxillary sinus floor augmentation techniques using bone grafts and bone substitutes are frequently used to enable placement of dental implants in the posterior maxilla. A previous case report demonstrated the possibility of promoting bone formation in the sinus by lifting the membrane without using a grafting material. However, the predictability of the technique is not known. Purpose: The aim of this study was to investigate whether sinus membrane elevation and the simultaneous insertion of titanium implants without additional grafting material constitute a valid technique for bone augmentation of the maxillary sinus floor. Materials and Methods: The study group comprised 10 patients in whom a total of 12 maxillary sinus floor augmentations were performed. A replaceable bone window was prepared in the lateral sinus wall with a reciprocating saw. The sinus membrane was dissected, elevated superiorly, and sutured to the sinus wall to create and maintain a compartment for blood clot formation. One to three dental implants were inserted through the residual bone and protruded at least 5 mm into the maxillary sinus. The bone window was replaced and secured with the overlying mucosa. Bone height was measured directly at each implant site at the time of insertion. Resonance frequency analysis (RFA) was performed on each implant at the time of initial placement, at abutment surgery, and after 12 months of functional loading. Computed tomography (CT) was performed in the immediate postoperative period and 6 months later, prior to exposure of the implants. Results: A total of 19 implants (Brånemark System®, TiUnite?, Nobel Biocare AB, Gothenburg, Sweden) in lengths of 10 to 15 mm were placed, with an average residual bone height of 7 mm (range, 4–10 mm). All implants remained clinically stable during the study period. Comparisons of pre‐ and postoperative CT radiography clearly demonstrated new bone formation within the compartment created by the sinus membrane elevation procedure. RFA measurements showed mean implant stability quotient values of 65, 66, and 64 at placement, at abutment connection, and after 12 months of loading, respectively. Conclusions: The study showed that there is great potential for healing and bone formation in the maxillary sinus without the use of additional bone grafts or bone substitutes. The secluded compartment created by the elevated sinus membrane, implants, and replaceable bone window allowed bone formation according to the principle of guided tissue regeneration. The precise mechanisms are not known, and further histologic studies are needed. Sinus membrane elevation without the use of additional graft material was found to be a predictable technique for bone augmentation of the maxillary sinus floor.     

侧壁开窗上颌窦底提升术后垂直向骨增量的观察研究

目的通过观察侧壁开窗上颌窦底提升术后垂直向骨增量的变化情况,研究其相关的影响因素。方法收集上颌后牙区牙列缺损行侧壁开窗上颌窦底提升术分期种植患者资料,对纳入病例的术前剩余牙槽骨高度(residual bone height,RBH)、术后当日垂直向骨高度、术后6个月垂直向骨高度及垂直向骨增量的变化情况进行观察。结果术后6个月较术后当日垂直向骨高度有显著性降低,降低量为0.56±0.25mm;上颌窦底黏膜厚度的术后6个月较术后当日垂直向骨增量的变化量无明显差异;在不同剩余牙槽骨高度情况下,术后6个月较术后当日垂直向骨增量的变化量有统计学差异,RBH大于5mm的患者相对RBH小于5mm的患者垂直向骨增量的降低值显著增加;上颌窦宽度与术后6个月较术后当日垂直向骨增量的降低值呈正相关。结论侧壁开窗上颌窦底提升术后6个月较术后当日存在垂直向骨增量的降低现象;剩余牙槽骨高度大于5mm时垂直向骨增量的降低值显著增加;上颌窦宽度与垂直向骨增量的降低值呈正相关。     

Measurement of volume changes after sinus floor augmentation with a phycogenic hydroxyapatite

PURPOSE: The purpose of this study was the determination of time-dependent volumetric changes of particulate sinus inlay grafts. A mixture of phycogenic hydroxyapatite (Algipore/C-Graft) and autologous bone collected from the surgical access area was used as the grafting material. MATERIALS AND METHODS: Thirty-three sinus floor augmentations using phycogenic hydroxyapatite combined with autologous bone collected at the augmentation site and venous blood were performed on 18 patients aged 57.4 +/- 12.5 years (mean +/- SD) with severe atrophy of the posterior maxilla. Graft volume was measured 1 to 14 days postoperatively and before the placement of dental implants 6.1 +/- 2.1 months later (mean +/- SD; range, 4 to 11 months) to evaluate the amount of time-dependent resorption of the implanted material on computerized tomographic (CT) images of the augmented region. The images were put into Digital Imaging and Communications in Medicine (DICOM) format and evaluated using the software library Analyze. The implanted bone replacement material was plotted manually on each CT slice, and the volume of the implanted material was calculated. RESULTS: The average volume loss of the bone replacement material during the observation period was 13.9% +/- 1.9% (mean +/- SEM). All sinus floor augmentations healed without complications except for delayed membrane exposure in 2 cases. DISCUSSION: The results indicate that the graft material, a mixture of Algipore, bone chips from the access area, and venous blood, exhibited a small volume loss over a period of approximately 6 months, thus providing predictable height for second-stage implant surgery. CONCLUSION: Further investigations are needed to evaluate long-term stability and implant success.     

Bone reaction to bovine hydroxyapatite for maxillary sinus floor augmentation: histologic results in humans

This study was designed to examine the sequential progress of healing, at two different time intervals, following delayed sinus augmentation using bovine hydroxyapatite (BHA) as the sole grafting material. Fourteen pairs of bone biopsies were taken from 10 patients after 6 and 12 months of healing, respectively. The biopsy specimens were examined histologically and histomorphometrically. The bone that was formed following sinus augmentation with BHA increased and matured over time up to 12 months after grafting; meanwhile, no overt signs of resorption of BHA were visible within the study period.     

Endoscopic and ultrasonographic evaluation of the maxillary sinus after combined sinus floor augmentation and implant insertion

OBJECTIVE: The aim of our study was a radiographic, endoscopic, and ultrasound follow-up of the maxillary sinus comparing 2 techniques of sinus floor augmentation. STUDY DESIGN: Sonograms, radiographs (Waters' view) of the sinuses, and endoscopy served before and during surgery to evaluate the maxillary sinus. One week after the operation, ultrasound and radiograph follow-up (Waters' view) were carried out. Six months after the operation, we performed an ultrasound follow-up along with uncovering the implants. If any pathologic condition was found, we took another x-ray film of the sinuses, performed another endoscopic examination, or both. RESULTS: In 23 of 63 patients, healing was uneventful. Waters' view revealed opacification of the maxillary sinus 1 week after surgery in 40 cases when the "window technique" was used. Sinusitis occurred 3 times, as a result of migration of bone chips in 2 patients. We lost 11 of 132 inserted implants during the healing and loading periods. CONCLUSION: Endoscope-controlled sinus floor augmentation may lower the complication rate in a remaining height of the jaws between 4 and 8 mm. In our group of patients, we proved by endoscopic examination that migration of cancellous bone sequestra was the reason for sinusitis. In case of infected bone grafts with antral symptoms, sinoscopy allowed debridement and removal of a sequestrum.     

Evaluation of bone volume changes after sinus floor augmentation with autogenous bone grafts

The aim of this study was to establish an objective method for quantitative evaluation of bone volume change after sinus augmentation. 11 sinuses in 9 patients were evaluated by computed tomography images taken before treatment (T0), and 3 months (T1) and at least 1 year (T2) after sinus augmentation. Based on the 3D digital subtraction technique, augmented bone images were extracted and bone volumes were calculated from voxel numbers of the extracted images. The mean augmented bone volumes at T1 and T2 were 2.46 cm3 and 1.85 cm3, respectively. These bone volume changes were statistically significant and the mean bone volume change ± SE was -24.8% ± 6.1%. Loss of augmented bone was observed in all except one of the patients. The correlation coefficient between bone volume change and elapsed time was -0.64, which was statistically significant and indicated that bone resorption progressed with elapse of time after sinus augmentation. The authors' method of analysis enabled visualization of augmented bone and objective assessment of bone volume change. Within the limited number of cases, the present investigation demonstrated a significant decrease in augmented bone volume between 3 and 23 months after surgery.     

基因强化组织工程骨用于上颌窦底提升的动物实验

目的 评价骨形态生成蛋白2( bone morphogenetic protein-2,BMP-2)基因强化骨髓间充质干细胞(bone marrow stromal cells,BMSC)复合Bio-Oss骨在上颌窦底提升术中的效果.方法 抽取12只犬髂部骨髓体外分离扩增BMSC,分别加入含BMP-2基因、绿色荧光蛋白(green fluorescent protein,GFP)基因的腺病毒载体共培养,观察转染效率,并植入裸鼠皮下观察成骨情况.将BMP-2基因强化BMSC-Bio-Oss复合骨随机植入犬一侧上颌窦底提升形成的空腔中为实验组,另一侧植入BMSC-Bio-Oss复合骨为空白对照组.分别于术后30、60、120 d行大体观察、CT检查、组织学检查和新生骨量分析.结果 裸鼠皮下可见新生骨,荧光显微镜示踪可见BMSC.犬上颌窦底提升30 d后,大体观察和CT检查示少量新骨形成,120 d后上颌窦内新骨生成致密,仅有少量Bio-Oss骨.新生骨量分析显示,与空白对照组[(19.67 ±5.73) mm2]相比,实验组新生骨量[(24.74±6.33) mm2]显著增多(P＜0.05).结论 BMP-2基因强化BMSC-Bio-Oss复合骨应用于上颌窦底提升术可获得良好的成骨效果.     

Effects of boric acid on bone formation after maxillary sinus floor augmentation in rabbits

Purpose

Augmentation of the maxillary sinus floor with bone grafting is commonly used for successful treatment of edentulous posterior maxilla with dental implants, and it is essential to maintain good bone volume and quality for long-term success of dental implants. The aim of this experimental study was to investigate the local and systemic effects of boric acid on new bone formation after maxillary sinus floor augmentation (MSFA).

Materials and methods

Twenty-four male, New Zealand rabbits were randomly divided into three groups with eight rabbits each, and bilateral MSFA was performed in each animal. An autogenous bone/xenograft mixture was used to augment the maxillary sinuses in each group. Group 1 was determined as control with no additional materials, whereas 3 mg/kg boric acid (BA) was added to the mixture in group 2, and 3 mg/kg boric acid solution added to drinking water daily in group 3.

Results

The animals were sacrificed and also histologic, histomorphometric, and immunnohistochemical analyses were performed at weeks 4 and 8. At week 4, bone regeneration was better in the local BA group than in the control and systemic BA groups (p?<?0.05). However, no significant difference was found among the groups in terms of bone regeneration at the end of week 8 (p?>?0.05).

Conclusion

Significant higher new bone formation was revealed by BA at early healing especially with local application. BA may be a therapeutic option for improving the bone regeneration.

     

Effect of maxillary sinus floor augmentation on sinus membrane thickness in computed tomography

Background: Little is known about maxillary sinus compliance, i.e., the intrinsic potential of the sinus membrane to resume its homeostatic status after the surgical trauma caused by sinus floor elevation. The aim of the present study is to investigate the effect of maxillary sinus floor augmentation on sinus membrane thickness. Methods: Within‐patient comparison of computed tomographic scans before bone grafting versus 4 to 6 months after bone grafting was performed. Changes in membrane thickness were evaluated in 65 maxillary sinus floor augmentation procedures via a lateral approach in 35 patients without clinical signs of sinus pathology at any time. Results: Sinus membrane thickness differed significantly before (0.8 ± 1.2 mm) versus after (1.5 ± 1.3 mm) augmentation surgery (P <0.001), with a mean increase of 0.8 ± 1.6 mm (maximum: 4.4 mm). Only 28% of augmented sinuses did not show membrane thickening. In non‐augmented control sinuses, there was no evidence of membrane thickness increase. Conclusions: The results indicate that the maxillary sinus membrane, even in healthy clinical conditions, undergoes morphologic modifications after sinus floor elevation, yet membrane reactions demonstrate significant variability. Future research on the effect of augmentation surgery on maxillary sinus physiology is recommended.     

Maxillary sinus floor augmentation in patients with maxillary sinus pseudocyst: case report

The maxillary sinus floor elevation procedure has gained popularity with predictable results, and is a safe, acceptable technique for bone augmentation, providing a base for dental implant treatment. Faint radiopaque lesions at the base of the maxillary sinus are frequent diagnoses on radiographs and must be identified during dental implant planning. Pseudocysts classically appear hemispheric, homogeneously opaque, and well delineated in panoramic and periapical radiographs. The great majority of these lesions are asymptomatic and do not require surgical treatment. In this case report, we present 4 patients who had a maxillary sinus floor elevation procedure using either crestal or lateral approaches in the presence of antral pseudocysts. No complications were encountered during follow-up periods in these patients and all implants are functioning successfully.     

上颌窦囊性改变的影像分类诊断及 上颌窦提升术的探讨

锥形束CT影像上常常可以发现上颌窦囊性改变的存在,这种改变是否影响上颌窦提升术的实施呢?这对临床医生造成了一定的困惑。本文结合临床上常见的各种囊性改变的锥形束CT影像表现,对上颌窦囊性改变的影像分类诊断进行介绍,并探讨囊性改变时上颌窦提升术的实施可行性、手术方式及术后黏膜的影像学改变等,以帮助临床医生作出正确判断。     

上颌窦囊性改变的影像分类诊断及上颌窦提升术的探讨

锥形束CT影像上常常可以发现上颌窦囊性改变的存在,这种改变是否影响上颌窦提升术的实施呢?这对临床医生造成了一定的困惑。本文结合临床上常见的各种囊性改变的锥形束CT影像表现,对上颌窦囊性改变的影像分类诊断进行介绍,并探讨囊性改变时上颌窦提升术的实施可行性、手术方式及术后黏膜的影像学改变等,以帮助临床医生作出正确判断。     

Endoscopically controlled sinus floor augmentation. A preliminary report.

Sinus augmentation has been advocated to be a surgical technique with predictable results in peri‐implant surgery. Endoscopic surgery of the maxillary sinus so far has been used as diagnostic procedure. In this paper, the use of endoscopy is described as a low invasive adjunctive technique in sinus floor augmentation. After preparation of the mucoperiosteum, bone grafts can be placed under endoscopic control between sinus floor and mucoperiosteum. A laterobasal approach via a small osteotomy and a transalveolar approach are possible for mucosal elevation and graft placement. First clinical results are reported. Endoscopic sinus lift may contribute to a reduction of perioperative morbidity, reduction of oroantal fistulae and control of graft position. The less invasive technique may allow to extend the indication for sinus augmentation.     

超声骨刀在上颌窦底外提升术中的临床应用观察

目的：探讨超声骨刀在开窗式上颌窦底外提升术中应用的临床效果及安全性。方法：对29名患者30侧行上颌窦底开窗式外提升术,用超声骨刀开窗,植入种植体共53枚（同期植入47枚,延期植入6枚）,6～8月后完成上部修复。修复后3、6及12个月复查。结果：术前平均剩余牙槽突高度为4．46 mm,术后平均提升高度为7．34 mm,植入53枚植体,没有发生黏膜穿孔。术后随访3～18个月没有发生种植体周围炎、种植体周围黏膜炎及种植体松动脱落。X线片显示种植体周围骨结合良好。种植体存留率及手术成功率均为100％。结论：超声骨刀在上颌窦底开窗式外提升术中安全可靠。