Bioactive Glass for Alveolar Ridge Augmentation

The restoration and recovery of the alveolar healing process are a challenge to dental surgeons to achieve satisfactory results at the osseointegration of implants and implant rehabilitation. Different operative technique and biomaterials are being used to reconstruct the framework of the alveolar process. One of the biomaterials used for this purpose is the bioactive glass. The aim of this study was to report clinical and histologic final results of 7 clinical reports of alveolar ridge augmentation using bioactive glass. Clinically, bioglass was able to maintain bone architecture of the alveolar bone and repaired satisfactory. Biopsy was performed on the histologic samples and showed bone formation in intimate contact to the particles of the biomaterial.

Alveolar ridge augmentation with the perforated and nonperforated bone grafts

Purpose: Autogenous bones are frequently used because of their lack of antigenicity, but good osteoconductive and osteoinductive properties. This study evaluated the biological behavior of perforated and nonperforated cortical block bone grafts.Methods: Ten nonsmoking patients who required treatment due to severe resorption of the alveolar process and subsequent implant installation were included in the study. The inclusion criteria was loss of one or more teeth; the presence of atrophy of the alveolar process with the indication of reconstruction procedures to allow rehabilitation with dental implants; and the absence of systemic disease, local infection, or inflammation. The patients were randomly divided into two groups based on whether they received a perforated (inner surface) or nonperforated graft. After a 6-month healing period, a biopsy was performed and osseointegrated implants were installed in the same procedure.Results: Fibrous connective tissue was evident at the interface in patients who received nonperforated grafts. However, full union between the graft and host bed was visible in those who had received a perforated graft.Conclusions: We found that cortical inner side perforations at donor sites increased the surface area and opened the medullary cavity. Our results indicate an increased rate of graft incorporation in patients who received such perforated grafts.

Changes in the volume and density of calvarial split bone grafts after alveolar ridge augmentation

OBJECTIVES: One main problem occurring after bone grafting is resorption, leading to insufficient bone volume and quality, and may subsequently cause dental implant failure. Comparison of graft volume and bone density of iliac crest and calvarial transplants determined by animal studies demonstrates significantly lower resorption of bone grafts harvested from the skull. This paper is the first clinical study evaluating bone volume and density changes of calvarial split bone grafts after alveolar ridge reconstruction. MATERIAL AND METHODS: Bone volume and density were determined using CT scans and the software program Dicom Works in a total of 51 calvarial grafts after alveolar ridge augmentation in 15 patients. CT scans were taken in all 15 patients immediately after grafting (T0) and before implantation after a postoperative period of 6 months (T1). In five patients (26 calvarial grafts), a 1-year follow-up was performed (T2). RESULTS: A mean volume reduction of 16.2% at T1 (15 patients) and 19.2% at T2 (five patients) was observed. Bone density was high--about 1000 Hounsfield units--and did not change during the 1-year period. At the time of implantation, 41 transplants were classified as quality 1 bone and 10 as quality 2-3 bone. Grafting area and the technique used for grafting (inlay or onlay graft) did not affect the postoperative bone volume reduction. Generalized osteoporosis did not increase the resorption rate of calvarial transplants. CONCLUSION: Based on these findings, calvarial split bone grafts are a promising alternative for alveolar ridge reconstruction in dental implantology.

[Management of a failing implant supporting a bar-retained maxillary overdenture by means of alveolar ridge augmentation. Implant loss and reimplantation]

This case report presents the treatment sequence of a 56 years old patient after he developed periimplantitis at the implant in position of tooth 22. This implant was integrated in an overdenture reconstruction connected to a soldered screw retained gold bar. The entire 2-stage procedure of implant explantation, simultaneous bone augmentation and new implant placement is documented. The onlay-graft was performed by means of the Transfer-Ring-Control System (Meisinger). The existing gold bar could be resoldered and adapted to the new implant. Accordingly the overdenture was relined and the female retainer mounted. The treatment period covered almost one year.

Alveolar ridge and maxillary sinus augmentation using rhBMP-2: a systematic review

Purpose: The aim of this systematic review was to evaluate clinical and safety data for recombinant human bone morpho-genetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier when used for alveolar ridge/maxillary sinusaugmentation in humans.Materials and Methods: Clinical studies/case ser ies published 1980 through June 2012 using rhBMP-2/ACS were searched.Studies meeting the following criteria were considered eligible for inclusion: >10 subjects at baseline and maxillary sinus oralveolar ridge augmentation not concomitant with implant placement.Results: Seven of 69 publications were eligible for review. rhBMP-2/ACS yielded clinically meaningful bone formationfor maxillary sinus augmentation that would allow placement of regular dental implants without consistent differencesbetween rhBMP-2 concentrations. Never theless, the statistical analysis showed that sinus augmentation following autog-enous bone graft was significantly greater (mean bone height: 1.6 mm, 95% CI: 0.5–2.7 mm) than for rhBMP-2/ACS(rhBMP-2 at 1.5 mg/mL). In extraction sockets, rhBMP-2/ACS maintained alveolar ridge height while enhancing alve olarridge width. Safety reports did not represent concerns for the proposed indications.Conclusions: rhBMP-2/ACS appears a promising alternative to autogenous bone grafts for alveolar ridge/maxillary sinusaugmentation; dose and carrier optimization may expand its efficacy, use, and clinical application.

Fate of autologous and fresh-frozen allogeneic block bone grafts used for ridge augmentation. A CBCT-based analysis

Objectives: To evaluate dimensional changes in autologous (AT) and fresh-frozen allogeneic (AL) block bone grafts 6 months after alveolar ridge augmentation. Material and methods: Twenty-six partially or totally edentulous patients treated either with fresh-frozen AL bone or AT bone onlay block grafts prior to implant placement (13 patients in each group), were included in this analysis. Patients received CBCT (i-CAT Classic) examinations prior to surgery and 14 days and 6 months after grafting. Differences in alveolar ridge area among the various observation times were evaluated by planimetric measurements on two-dimensional CBCT images of the grafted regions. Nineteen grafted blocks from each group were evaluated. Results: Significant increase in alveolar ridge dimensions, allowing implant placement, was obtained with both types of grafts 6 months after grafting; no significant differences in alveolar ridge area were observed between the groups at the various observation times. However, graft resorption in the AL group was significantly larger compared to that in the AT group at 6 months. Conclusions: Larger bone graft resorption was seen in patients treated with fresh-frozen AL bone than in those treated with AT bone 6 months following alveolar ridge augmentation. © 2011 John Wiley & Sons A/S.

Horizontal ridge augmentation of the atrophic anterior maxilla using rhBMP-2/ACS or autogenous bone grafts: A proof-of-concept randomized clinical trial

Aim To compare the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge carrier (ACS) with autogenous bone graft for augmentation of the edentulous atrophic anterior maxilla. Methods Twenty-four subjects were enrolled in a randomized, controlled, parallel-group, open-label clinical trial. Subjects either received rhBMP-2/ACS (1.5 mg/ml) or particulated autogenous bone harvested from the mandibular retromolar region. A titanium-mesh was used to provide space and wound stability. A guide was used to standardize clinical recordings using an analogue caliper. Alveolar ridge width was also assessed using cone-beam computed tomography. Results rhBMP-2/ACS yielded significantly greater radiographic horizontal bone gain compared with autogenous bone graft at immediate subcrestal levels (1.5 ± 0.7 versus 0.5 ± 0.9 mm; p = 0.01); non-significant differences were observed at mid- (2.9 ± 0.8 versus 2.9 ± 0.9 mm; p = 0.98) and apical (1.7 ± 0.9 versus 1.8 ± 1.1 mm; p = 0.85) crestal levels. No significant differences in clinical horizontal bone gain were observed at 6 months between rhBMP-2/ACS and autogenous bone graft (3.2 ± 0.9 mm versus 3.7 ± 1.4 mm; p = 0.31). Sixty-two implants were placed after 6 month of healing with no significant differences between groups for number of implants, implant size, primary stability and survival. Conclusions rhBMP-2/ACS appears a realistic alternative for augmentation of the edentulous atrophic anterior maxilla. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Graft incorporation and implant osseointegration following the use of autologous and fresh-frozen allogeneic block bone grafts for lateral ridge augmentation

Objectives: To compare autogenous bone (AT) and fresh-frozen allogeneic bone (AL) in terms of histomorphometrical graft incorporation and implant osseointegration after grafting for lateral ridge augmentation in humans. Materials and methods: Thirty-four patients were treated with either AL (20 patients) or AT (14 patients) onlay grafts. During implant installation surgery 6 months after grafting, cylindrical biopsies were harvested perpendicularly to the lateral aspect of the augmented alveolar ridge. Additionally, titanium mini-implants were installed in the grafted regions, also perpendicularly to the ridge; these were biopsied during second-stage surgery. Histological/histomorphometric analysis was performed using decalcified and non-decalcified sections. Results: Histological analysis revealed areas of necrotic bone (NcB) occasionally in contact with or completely engulfed by newly formed vital bone (VB) in both AT and AL groups (55.9 ± 27.6 vs. 43.1 ± 20.3, respectively; P = 0.19). Statistically significant larger amounts of VB (27.6 ± 17.5 vs. 8.4 ± 4.9, respectively; P = 0.0002) and less soft connective tissue (ST) (16.4 ± 15.6 vs. 48.4 ± 18.1, respectively; P ≤ 0.0001) were seen for AT compared with AL. No significant differences were observed between the groups regarding both bone-to-implant contact (BIC) and the bone area between implant threads (BA) on the mini-implant biopsies. Conclusion: Allogeneic bone block grafts may be an option in cases where a limited amount of augmentation is needed, and the future implant can be expected confined within the inner aspect of the bone block. However, the clinical impact of the relatively poor graft incorporation on the long-term performance of oral implants placed in AL grafts remains obscure. © 2013 John Wiley & Sons A/S.

A digital evaluation of alveolar ridge preservation at implants placed immediately into extraction sockets: an experimental study in the dog

Objective: To compare with pristine sites bone resorption and soft tissue adaptation at implants placed immediately into extraction sockets (IPIES) in conjunction with deproteinized bovine bone mineral (DBBM) particles and a collagen membrane.Material and methods: The mesial root of the third premolar in the left side of the mandible was endodontically treated (Test). Flaps were elevated, the tooth hemi-sectioned, and the distal root removed to allow the immediate installation of an implant into the extraction socket in a lingual position. DBBM particles were placed into the defect and on the outer contour of the buccal bony ridge, concomitantly with the placement of a collagen membrane. A non-submerged healing was allowed. The premolar on the right side of the mandible was left in situ (control). Ground sections from the center of the implant as well as from the center of the distal root of the third premolar of the opposite side of the mandible were obtained. The histological image from the implant site was superimposed to that of the contralateral pristine distal alveolus, and dimensional variation evaluated for the hard tissue and the alveolar ridge.Results: After 3 months of healing, both histological and photographic evaluation revealed a reduction of hard and soft tissue dimensions.Conclusion: The contour augmentation performed with DBBM particles and a collagen membrane at the buccal aspects of implants placed IPIES was not able to maintain the tissue volume.

Cone Beam Computed Tomographic Evaluation of a Maxillary Alveolar Ridge Reconstruction With Iliac Crest Graft and Implants

The present article discusses an atrophic maxilla reconstruction with iliac crest bone block and particulate grafts and dental implants. Onlay block grafts were used to restore bone volume of the anterior maxilla, whereas bilateral sinus floor augmentation was performed using a particulate graft. Ten months after the grafting surgery, 9 dental implants were placed to rehabilitate the case. Results of a 7-year follow-up were obtained clinically and by cone beam computed tomographic images.

Lateral ridge augmentation using equine- and bovine-derived cancellous bone blocks: a feasibility study in dogs

OBJECTIVES: The aim of the present study was to histologically evaluate and compare a new prototype collagen type I/III-containing equine- (EB) and a bovine- (BB) derived cancellous bone block in a dog model. MATERIALS AND METHODS: Four standardized box-shaped defects were bilaterally created at the buccal aspect of the alveolar ridge in the lower jaws of five beagle dogs and randomly allocated to either EB or BB. Each experimental site was covered by a native (non-crosslinked) collagen membrane and left to heal in a submerged position for 12 weeks. Dissected blocks were processed for semi-/and quantitative analyses. RESULTS: Both groups had no adverse clinical or histopathological events (i.e. inflammatory/foreign body reactions). BB specimens revealed no signs of biodegradation and were commonly embedded in a fibrous connective tissue. New bone formation and bony graft integration were minimal. In contrast, EB specimens were characterized by a significantly increased cell (i.e. osteoclasts and multinucleated giant cells)-mediated degradation of the graft material (P<0.001). The amount and extent of bone ingrowth was consistently higher in all EB specimens, but failed to reach statistical significance in comparison with the BB group (P>0.05). CONCLUSIONS: It was concluded that the application of EB may not be associated with an improved bone formation than BB.

Partial lateralization of the nasopalatine nerve at the incisive foramen for ridge augmentation in the anterior maxilla prior to placement of dental implants: a retrospective case series evaluating self-reported data and neurosensory testing

The objective of this study was to assess implant therapy after a staged guided bone regeneration procedure in the anterior maxilla by lateralization of the nasopalatine nerve and vessel bundle. Neurosensory function following augmentative procedures and implant placement, assessed using a standardized questionnaire and clinical examination, were the primary outcome variables measured. This retrospective study included patients with a bone defect in the anterior maxilla in need of horizontal and/or vertical ridge augmentation prior to dental implant placement. The surgical sites were allowed to heal for at least 6 months before placement of dental implants. All patients received fixed implant-supported restorations and entered into a tightly scheduled maintenance program. In addition to the maintenance program, patients were recalled for a clinical examination and to fill out a questionnaire to assess any changes in the neurosensory function of the nasopalatine nerve at least 6 months after function. Twenty patients were included in the study from February 2001 to December 2010. They received a total of 51 implants after augmentation of the alveolar crest and lateralization of the nasopalatine nerve. The follow-up examination for questionnaire and neurosensory assessment was scheduled after a mean period of 4.18 years of function. None of the patients examined reported any pain, they did not have less or an altered sensation, and they did not experience a "foreign body" feeling in the area of surgery. Overall, 6 patients out of 20 (30%) showed palatal sensibility alterations of the soft tissues in the region of the maxillary canines and incisors resulting in a risk for a neurosensory change of 0.45 mucosal teeth regions per patient after ridge augmentation with lateralization of the nasopalatine nerve. Regeneration of bone defects in the anterior maxilla by horizontal and/or vertical ridge augmentation and lateralization of the nasopalatine nerve prior to dental implant placement is a predictable surgical technique. Whether or not there were clinically measurable impairments of neurosensory function, the patients did not report them or were not bothered by them.

Incorporação e remodelação de enxertos homólogos na reconstrução alveolar em humanos: análise tomográfica, histológica e histomorfométrica

Enxertos ósseos homólogos congelados têm sido documentados apresentando bons resultados clínicos como substituto ao material autógeno nas reconstruções alveolares. Entretanto, dados referentes à incorporação e remodelação destes enxertos não estão disponíveis na literatura. Este estudo tem por objetivo determinar um período ótimo de espera para instalação de implantes em rebordos reconstruídos com enxertos ósseos homólogos em bloco no que se refere à incorporação e reabsorção. 24 pacientes foram submetidos à reconstrução alveolar óssea homóloga previamente à instalação de implantes. Os indivíduos foram alocados randomicamente em um de 3 grupos de acordo com o tempo de espera para o segundo estágio cirúrgico (4, 6 e 8 meses). Análises tomográficas, histológicas e histomorfométricas foram utilizadas a fim de determinar o grau de reabsorção e incorporação dos enxertos nos diferentes intervalos de tempo para cada grupo. Os dados de reabsorção sofrida pelos enxertos demonstraram diferenças estatisticamente significativas para os três intervalos de espera. Da mesma forma, parâmetros histomorfométricos como contagem de osteócitos e quantificação de remanescentes de osso homólogo nas biópsias apresentaram diferenças significativas entre os grupos. De acordo com os dados do presente trabalho, no que diz respeito à remodelação e incorporação, o período mais favorável à instalação dos implantes a curto prazo após recontruções com enxertos homólogos é de 4 meses.

Fresh-frozen human bone allograft in vertical ridge augmentation: clinical and tomographic evaluation of bone formation and resorption

The aim of the current study is to evaluate fresh-frozen human bone allografts (FHBAs) used in vertical ridge augmentation clinically and by computed tomography, and to analyze the resulting bone formation and graft resorption. Sixteen FHBAs were grafted in the maxillae and mandibles of 9 patients. The FHBAs, which were provided by the Musculoskeletal Tissue Bank of Marilia Hospital (Unioss), were frozen at -80A degrees C. After 7 months, dental implants were placed and bone parameters were evaluated. Vertical bone formation was measured by computerized tomography before (T0) and at 7 months (T1) after the surgical procedure. Bone graft resorption was measured clinically from a landmark screw head using a periodontal probe. The results were analyzed by Student's t-test. Significant differences existed in the bone formation values at T0 and T1, with an average change of 4.03 +/- A 1.69 mm. Bone graft resorption values were 1.0 +/- A 0.82 mm (20%). Implants were placed with varying insertion torque values (35-45 Ncm), and achieved primary stability. This study demonstrates that FHBAs promote satisfactory vertical bone formation with a low resorption rates, good density, and primary implant stability.

Vertical Bone Augmentation Using a Polytetrafluoroethylene Nonporous Barrier for Osseointegrated Implants Partially Inserted in Tibiae of Rabbits

Purpose: The aim of this study was to evaluate the possibility of obtaining guided bone regeneration using a poly-tetrafluoroethylene (PTFE) nonporous barrier for 2 endosseous implants, partially inserted in tibiae of rabbits.Materials and Methods: Histologic characteristics of the interface between titanium implants (one group with titanium plasma-coated implants and the other group with acid-treated surfaces) and of the regenerated bone were also studied. Twenty screw-vent implants were placed in tibiae of 5 male New Zealand rabbits, 2 at the right side and 2 at the left side, protruding 3 mm from the bone level, to create a horizontal bone defect. At the experimental group the implants were with a PTFE nonporous barrier, whereas no barriers were used in contralateral implants. Animals were sacrificed 3 months after surgery and biopsy specimens were evaluated histologically and histomorphometrically under light microscopy. Student's t test was used for statistical analysis.Results: The histologic measurements showed a mean gain in bone height of 2.15 and 2.42 mm for the barrier group and 1.95 and 0.43 mm for the control group, for the titanium plasma-spray and acid-treated implant surfaces, respectively.Conclusion: The results of the investigation revealed that the placement of implants protruding 3 nun from crestal bone defects may result in vertical bone augmentation using a nonporous PTFE barrier. (Implant Dent 2009;18:182-191)