Vertical alveolar ridge augmentation by means of a titanium mesh and autogenous bone grafts

The aim of this study is to evaluate a surgical protocol for vertical ridge augmentation in the maxilla and mandible using autogenous onlay bone graft associated with a titanium mesh. A group of 18 partially edentulous patients, presenting the need for vertical bone augmentation of at least 4 mm, were treated before implant placement. During the first surgery, an autogenous bone graft was harvested from either the mandibular ramus or the mental symphysis and secured by means of titanium screws. Particulate bone was added and a titanium micro-mesh was used to stabilize and protect the graft. After a mean interval of 4.6 months, meshes and screws were removed and 37 endosseous implants were successfully placed. The desired bone gain was reached in all patients. Mean vertical bone augmentation obtained was 4.8 mm (range 4-7 mm). No major complications were recorded at recipient or donor sites. Abutment connection was carried out 2-3 months after implant placement. No implant was lost. Clinical parameters and probing depth, after prosthetic reconstruction, demonstrated the presence of a healthy peri-implant mucosa. The preliminary results suggest that, by using the presented technique, patients can be successfully rehabilitated by means of implant-supported prosthesis 6-7 months after the first surgery, even in case of severely atrophied maxilla.     

Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone

Objectives: The aim was to evaluate histologically the outcome of a bioglass and autogenous bone (at 1 : 1 ratio) composite implantation for transalveolar sinus augmentation. Methods: In 31 patients, during implant installation ca. 4 months after sinus augmentation, biopsies were harvested through the transalveolar osteotomy by means of a trephine bur and non‐decalcified sections through the long axis of the cylinder were produced. After a strict selection process, taking into account the presurgical residual bone height and biopsy length, 8 and 15 biopsies representing the new tissues formed inside the sinus and the transalveolar osteotomy, respectively, qualified for analysis. The tissue fractions occupied by newly formed bone (mineralized tissue+bone marrow), soft connective tissue, residual biomaterial+empty spaces, and debris inside the sinus cavity or the transalveolar osteotomy were estimated. Results: Bone and connective tissue fraction in the newly formed tissues inside the sinus cavity averaged 23.4 ± 13.2% and 54.1 ± 23.5%, respectively. Residual biomaterial, empty spaces, and debris averaged 1.9 ± 3.5%, 10.5 ± 6.3%, and 8.4 ± 14.5%, respectively. In the transalveolar osteotomy, bone and connective tissue fraction averaged 41.6 ± 14.3% and 46.1 ± 13%, respectively, while the amount of residual biomaterial, empty spaces, and debris was 2.8 ± 5%, 4.7 ± 1.9%, and 3.2 ± 2.6%, respectively. Statistically significant differences between the sinus cavity and the transalveolar osteotomy were found only for bone and empty spaces' values (P=0.02 and 0.04, respectively). Conclusion: Sinus augmentation with a bioglass and autogenous bone composite is compatible with bone formation that, in a short distance from the floor of the sinus, shows similar density as that reported previously for other commonly used bone substitutes. New bone fraction inside the transalveolar osteotomy was almost twice as much as in the sinus cavity, while the amount of residual biomaterial was much less than that inside the sinus. To cite this article :
Stavropoulos A, Sima C, Sima A, Nyengaard J, Karring T, Sculean A. Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone.
Clin. Oral Impl. Res. 23 , 2012; 125–131.
doi: 10.1111/j.1600‐0501.2011.02161.x     

Horizontal ridge augmentation using autogenous block grafts and the guided bone regeneration technique with collagen membranes: a clinical study with 42 patients

OBJECTIVE: To analyze the clinical outcome of horizontal ridge augmentation using autogenous block grafts covered with an organic bovine bone mineral (ABBM) and a bioabsorbable collagen membrane. MATERIAL AND METHODS: In 42 patients with severe horizontal bone atrophy, a staged approach was chosen for implant placement following horizontal ridge augmentation. A block graft was harvested from the symphysis or retromolar area, and secured to the recipient site with fixation screws. The width of the ridge was measured before and after horizontal ridge augmentation. The block graft was subsequently covered with ABBM and a collagen membrane. Following a tension-free primary wound closure and a mean healing period of 5.8 months, the sites were re-entered, and the crest width was re-assessed prior to implant placement. RESULTS: Fifty-eight sites were augmented, including 41 sites located in the anterior maxilla. The mean initial crest width measured 3.06 mm. At re-entry, the mean width of the ridge was 7.66 mm, with a calculated mean gain of horizontal bone thickness of 4.6 mm (range 2-7 mm). Only minor surface resorption of 0.36 mm was observed from augmentation to re-entry. CONCLUSIONS: The presented technique of ridge augmentation using autogenous block grafts with ABBM filler and collagen membrane coverage demonstrated successful horizontal ridge augmentation with high predictability. The surgical method has been further simplified by using a resorbable membrane. The hydrophilic membrane was easy to apply, and did not cause wound infection in the rare instance of membrane exposure.     

Vertical ridge augmentation by expanded-polytetrafluoroethylene membrane and a combination of intraoral autogenous bone graft and deproteinized anorganic bovine bone (Bio Oss)

Objective: To evaluate, from a histological and histomorphometrical perspective, the efficacy of a 1 : 1 mixture of deproteinized bovine bone mineral (DBBM) and autogenous bone graft associated with an expanded‐polytetrafluoroethylene (e‐PTFE) membrane for vertical ridge augmentation in the human. Material and methods: Seven patients with 10 surgical sites requiring vertical ridge augmentation of partially edentulous lower jaws were included in the study. The vertical augmentation procedure was performed combining a titanium‐reinforced e‐PTFE Gore‐Tex membrane with a composite graft consisting of a 1 : 1 ratio of DBBM (Bio‐Oss) and autogenous bone. Twenty‐seven Branemark implants have been inserted. Eleven biopsies from the regenerated area were analyzed histologically and histomorphometrically. Results: The healing period was uneventful in nine surgical sites. In one site the membrane showed an exposure after 3 months. At the abutment connection, all implants appeared stable and submerged by a hard regenerated tissue clinically similar to bone. The histological analysis showed new bone formation and ongoing remodelling of the autogenous bone and the DBBM particles. Conclusions: The findings from the present clinical and histological study support the use of a 1 : 1 combination of DBBM and autogenous bone chips for vertical ridge augmentation by means of guided bone regeneration techniques. The regenerated bone may lead to proper osseointegration of a dental implant inserted at the time of the regenerative procedure or after a healing period of at least 6 months. DBBM undergoes very slow resorption and substitution with new bone. Furthermore, long‐term clinical studies are needed to confirm the positive effect of DBBM in enhancing the lasting stability of the vertically augmented bone.     

Lateral ridge augmentation by the use of grafts comprised of autologous bone or a biomaterial. An experiment in the dog

OBJECTIVE: The present investigation was performed to determine if a block of Bio-Oss used as an onlay graft can be used as a scaffold for new bone formation. MATERIAL AND METHODS: Five mongrel dogs were used. The mandibular premolars were extracted. On both sides of the mandible, the buccal bone plate was resected and defects, about 25 mm long, 8 mm high and 5 mm wide, were produced After 3 months of healing, a second surgical procedure was performed. In the left side, a block of Bio-Oss was adjusted to the buccal bone wall. The graft had the shape of a cylinder and was retained with a miniscrew and covered with a collagen membrane. In the contra-lateral side of the mandible, a block biopsy was first obtained from the ascending ramus. This bone graft had the shape of a cylinder that was 8 mm in diameter and 3 mm thick. The graft was transferred to the experimental site, adjusted to the buccal wall, retained with a miniscrew, and covered with a membrane. The flaps were repositioned and closed with sutures to ensure a complete coverage of the experimental sites. After 6 months of healing, the dogs were sacrificed and the experimental sites dissected. The biopsies were processed for ground sectioning. The sections were stained in toluidine blue, examined in the microscope, and a number of histo- and morphometric assessments made. RESULTS: The study demonstrated that cortical bone used as an onlay graft in the lateral aspect of the alveolar ridge, during a 6-month period of healing integrated with the host bone but underwent marked peripheral resorption. Thus, close to 30% of the height and 50% of the length of the graft was replaced with connective tissue. It was further observed that while the dimensions of a graft which contained a scaffold of cancellous bovine bone mineral remained unchanged, only moderate amounts of new bone formed at the base of this graft. CONCLUSION: Grafts of autologous cortical bone, placed on the surface of a one-wall defect, may undergo marked resorption during healing. A similar graft of Bio-Oss may retain its dimension, and limited amounts of new bone will form within the biomaterial.     

外斜线取骨自体骨移植及其他牙槽嵴骨增量法的研究进展

针对严重骨缺损且有种植修复意向的牙列缺损位点，自体骨移植是实现种植体三维方向充足骨量的“经典方案”，常用的口内供骨区有颏部和外斜线区域。相比颏部取骨，下颌骨外斜线取骨移植后神经并发症少，但跟其他牙槽嵴骨增量方式相比，术后骨吸收率大。本文重点讲述下颌骨外斜线块状取骨及其局限性，并阐述了其他临床应用广泛的牙槽骨增量方法，对比移植骨术后牙槽嵴宽度及高度变化、术后骨吸收率，为临床提供减小外斜线块状取骨局限性的其他骨增量方法。