Maxillary sinus floor augmentation using bioactive glass granules and autogenous bone with simultaneous implant placement. Clinical and histological findings

This clinical study was undertaken to: 1) evaluate the use of bioactive glass Biogran combined with autogenous bone as grafting material for maxillary sinus augmentation with simultaneous implant placement using radiography and histology; and 2) document the short-term post-loading success of implants inserted in sinus cavities augmented with this material. Unilateral or bilateral sinus augmentation was performed in 12 patients with 3-5 mm of alveolar crestal bone height in the posterior maxilla prior to grafting. The sinuses were grafted with bioactive glass mixed in a 4:1 ratio with autogenous bone. Simultaneously, 2-3 threaded titanium implants were inserted into the augmented sinuses. Second stage surgery was carried out 9 to 12 months post implantation. At abutment connection, 10 core biopsy specimens were taken from different grafted sites and evaluated histologically. All 27 implants were clinically stable at second stage surgery. A mean increase in mineralized tissue height of 7.1 +/- 1.6 mm was evident when comparing the pre-surgical CT scans with those performed 9-12 months following the sinus augmentation procedure. Evaluation of the cores yielded a mean of 30.6 +/- 5.7% of bone tissue in the grafted sites. One implant failed during the prosthetic phase while the remaining 26 implants were stable 12 months post loading. This study suggests that Biogran/autogenous bone graft combination used in one-stage sinus augmentation yields sufficient quality and volume of mineralized tissue for predictable simultaneous implant placement in patients with 3-5 mm of bone height prior to grafting.     

Bone reformation and implant integration following maxillary sinus membrane elevation: an experimental study in primates

Background: Recent clinical studies have described maxillary sinus floor augmentation by simply elevating the maxillary sinus membrane without the use of adjunctive grafting materials. Purpose: This experimental study aimed at comparing the histologic outcomes of sinus membrane elevation and simultaneous placement of implants with and without adjunctive autogenous bone grafts. The purpose was also to investigate the role played by the implant surface in osseointegration under such circumstances. Materials and Methods: Four tufted capuchin primates had all upper premolars and the first molar extracted bilaterally. Four months later, the animals underwent maxillary sinus membrane elevation surgery using a replaceable bone window technique. The schneiderian membrane was kept elevated by insertion of two implants (turned and oxidized, Brånemark System®, Nobel Biocare AB, Göteborg, Sweden) in both sinuses. The right sinus was left with no additional treatment, whereas the left sinus was filled with autogenous bone graft. Implant stability was assessed through resonance frequency analysis (Osstell^TM, Integration Diagnostics AB, Göteborg, Sweden) at installation and at sacrifice. The pattern of bone formation in the experimental sites and related to the different implant surfaces was investigated using fluorochromes. The animals were sacrificed 6 months after the maxillary sinus floor augmentation procedure for histology and histomorphometry (bone‐implant contact, bone area in threads, and bone area in rectangle). Results: The results showed no differences between membrane‐elevated and grafted sites regarding implant stability, bone‐implant contacts, and bone area within and outside implant threads. The oxidized implants exhibited improved integration compared with turned ones as higher values of bone‐implant contact and bone area within threads were observed. Conclusions: The amount of augmented bone tissue in the maxillary sinus after sinus membrane elevation with or without adjunctive autogenous bone grafts does not differ after 6 months of healing. New bone is frequently deposited in contact with the schneiderian membrane in coagulum‐alone sites, indicating the osteoinductive potential of the membrane. Oxidized implants show a stronger bone tissue response than turned implants in sinus floor augmentation procedures.     

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.     

Changes of mineralization of free autogenous bone grafts used for sinus floor elevation

For augmentations before implant placement in areas of minor bone quantity, autogenous bone is considered the reference to all bone substitutes used alternatively. Autogenous bone transplants originate from various donor areas and can be prepared in different ways before augmentation. They may either be used as block grafts or may be milled to granules that can be used solitarily or in combination with a bone substitute. In a prospective study, 61 patients of the Maxillofacial Surgery Department of our University receiving two-stage sinus floor elevation because of insufficient bone supply were randomly selected. At first-stage surgery, the local augmentation procedure, monocortical probes were obtained on the site of bone harvesting. At second-stage surgery, the implant insertion 6 months after the elevation procedure, bone cores were harvested in the areas of implant placement. Donor regions were the following three areas: the posterior (N=28) and anterior pelvic region (N=15) and the chin region (N=18). The implanted bone in all three groups was particulated to granules of 2-3 mm(2) using a bone mill. All biopsies were analyzed by means of microradiography. The anterior pelvic bone grafts showed a mineralized tissue grade of 35.1+/-7.6% before milling and augmentation. The posterior pelvic bone grafts exhibited a mineralization of 30.7+/-9.5% and the chin bone grafts 74.6+/-8.6%. At second-stage surgery after 6 months, the mineralization was 36.1+/-7.59% in the areas where bone grafts from the anterior pelvic crest were used. Probes harvested from sites with posterior pelvic bone augmentations showed a mineralization rate of 34.5+/-6.5%, and sites were chin bone grafts were applied expressed a mineralization of 54+/-8.6% (P=0.003 compared with the pre-operative value). The comparison of the microradiographical results demonstrated significant differences in the mineralization grades depending on the origin of the graft. The origin of the grafts and their remodeling influenced the mineralization rates found at 6 months. How these data may influence the long-term clinical outcome considering implant survival and bone resorption has to be examined in further long-term studies.     

Sinusfloor elevation and grafting with autogenous iliac crest bone.

Insufficient bone height in the posterior area of the maxilla, due to expansion of the maxillary sinus and atrophic reduction of the alveolar process of the maxilla, represents a contra-indication for insertion of dental implants. This anatomic problem can, in many cases, be solved by augmentation of the floor of the maxillary sinus. This surgical technique was introduced by Tatum. The so-called top hinge door method creates a new floor of the maxillary sinus at a more cranial level. Underneath this new floor the existing space is filled with a bone graft. Implantation in the alveolar process with increased bone height allows insertion of dental implants. This sinus grafting technique was used in the present study. In total, 62 sinusfloor elevations were performed with cancellous iliac bone grafts in 42 patients. In those 62 augmented sinuses, 161 ITI screw type implants were inserted. The follow-up was 1-6 years after implantation. In 2 cases infections occurred. One implant needed an extended integration time. No implants were lost. The ITI solid screw implant appears to be a suitable implant following sinusfloor elevation operations, due to its rough surface, its shape and the size of the thread. The sinusfloor elevation procedure with autogenous cancellous bone graft appears to be a valuable and reliable pre-implantological procedure, provided a proper pre-operative investigation and careful surgery are performed. This procedure allows dental implant placement with a high success rate.     

Sinus floor elevation and grafting with autogenous iliac crest bone

Insufficient bone height in the posterior area of the maxilla, due to expansion of the maxillary sinus and atrophic reduction of the alveolar process of the maxilla, represents a contraindication for insertion of dental implants. This anatomic problem can, in many cases, be solved by augmentation of the floor of the maxillary sinus. This surgical technique was introduced by Tatum. The so‐called top hinge door method creates a new floor of the maxillary sinus at a more cranial level. Underneath this new floor the existing space is filled with a bone graft. Implantation in the alveolar process with increased bone height allows insertion of dental implants. This sinus grafting technique was used in the present study. In total, 62 sinusfloor elevations were performed with cancellous iliac bone grafts in 42 patients. In those 62 augmented sinuses, 161 ITT screw type implants were inserted. The follow‐up was 1–6 years after implantation. In 2 cases infections occurred. One implant needed an extended integration time. No implants were lost. The ITI solid screw implant appears to be a suitable implant following sinusfloor elevation operations, due to its rough surface, its shape and the size of the thread. The sinusfloor elevation procedure with autogenous cancellous bone graft appears to be a valuable and reliable pre-implantological procedure, provided a proper pre‐operative investigation and careful surgery are performed. This procedure allows dental implant placement with a high success rate.     

Volumetric changes of the graft after maxillary sinus floor augmentation with Bio-Oss and autogenous bone in different ratios: a radiographic study in minipigs

Objective: The objective of the present study was to learn about the volumetric changes of the graft after maxillary sinus floor augmentation with Bio‐Oss and autogenous bone from the iliac crest or the mandible in different ratios in minipigs. Material and methods: Bilateral maxillary sinus floor augmentation was performed in 40 minipigs with: (A) 100% autogenous bone, (B) 75% autogenous bone and 25% Bio‐Oss, (C) 50% autogenous bone and 50% Bio‐Oss, (D) 25% autogenous bone and 75% Bio‐Oss, and (E) 100% Bio‐Oss. The autogenous bone graft was harvested from the iliac crest or the mandible and the graft composition was selected at random and placed concomitant with implant placement. Computed tomographies of the maxillary sinuses were obtained preoperatively, immediately postoperatively, and at euthanasia after 12 weeks. The volumetric changes of the graft were estimated using the Cavalieri principle and expressed as mean percentage with a 95% confidence interval (CI). Results: The mean volume of the graft was reduced by (A) 65% (95% CI: 60–70%), (B) 38% (95% CI: 35–41%), (C) 23% (95% CI: 21–25%), (D) 16% (95% CI: 12–21%), and (E) 6% (95% CI: 4–8%). The volumetric reduction was significantly influenced by the ratio of Bio‐Oss and autogenous bone (P<0.001), but not by the origin of the autogenous bone graft (P=0.2). Conclusions: The volume of autogenous bone grafts from the iliac crest and the mandible is reduced significantly after maxillary sinus floor augmentation in minipigs. The graft volume is better preserved after the addition of Bio‐Oss and the volumetric reduction is significantly influenced by the ratio of Bio‐Oss and autogenous bone. However, further studies are needed addressing the amount of new bone formation and bone‐to‐implant contact before the final conclusion can be made about the optimal ratio of Bio‐Oss and autogenous bone. To cite this article:
Jensen T, Schou S, Svendsen PA, Forman JL, Gundersen HJG, Terheyden H, Holmstrup P. Volumetric changes of the graft after maxillary sinus floor augmentation with Bio‐Oss and autogenous bone in different ratios: a radiographic study in minipigs.
Clin. Oral Impl. Res. 23 , 2012; 902–910
doi: 10.1111/j.1600‐0501.2011.02245.x     

Maxillary sinus augmentation using different grafting materials and dental implants in monkeys. Evaluation of autogenous bone combined with porous hydroxyapatite.

The aim of this study was to evaluate clinically, histologically, and histometrically the use of autogenous bone combined with porous hydroxyapatite (Interpore 200®) as a grafting material for maxillary sinus augmentation procedures. In 4 adult male rhesus monkeys (Macaca mulatta) the 1st, 2nd and 3rd maxillary molars on one side of the jaws were extracted. After a healing period of 3 months. maxillary sinus augmentation procedures were performed in each monkey, and the sinuses were grafted with autogenous bone from the monkeys' tibia mixed in a 3:1 ratio with porous hydroxyapatite. At the same time. 2 pure titanium plasma-sprayed IMZB cylinder implants were immediately placed into the augmented sinuses (i.e. simultaneous implants-loaded group). After 4 months, 2 additional similar implants were placed into the previously augmented sinuses (i.e. delayed implants-loaded group). Four months later, the abutment connection was performed and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received similar treatment with the exception that the extractions were performed 7 months after those in the opposite side and that the implants were not loaded. Thus, 2 additional study groups (i.e. simultaneous implants unloaded group and delayed implants unloaded group) were obtained. Clinically, all loaded implants were stable at the day of sacrifice. Histologically, the grafted sinuses exhibited a significant amount of new bone formation. The porous hydroxyapatite granules appeared integrated with the newly formed bone. Histometric analyses revealed that delayed implant placement resulted in a greater amount of direct mineralized bone-to-implant contact in the augmented area than the simultaneous implant placement. Furthermore, the percentage of direct mineralized bone-to-implant contact was far more significant in the residual bone than in the augmented area. It was concluded that the autogenous bone/porous hydroxyapatite graft combination enhanced bone formation and mineralized bone-to-implant contact in the augmented sinuses and that the delayed implant placement may be favorable for sinus augmentation procedures.     

Stability Evaluation of Implants Integrated in Grafted and Nongrafted Maxillary Bone: A Clinical Study from Implant Placement to Abutment Connection

Background: Clinical studies have shown a higher degree of implant failures in grafted bone compared with normal nongrafted maxillary bone. Additionally, a prolonged time for integration of titanium implants in grafted block bone has been shown by means of resonance frequency analysis (RFA). Purpose: The aim of this prospective study was to compare the stability of implants placed in particulate bone, onlay block bone, interpositional bone, and nongrafted maxillary bone during the early phase of osseointegration using RFA and implant failure. Material and Methods: Thirty‐five patients with edentulism in the maxilla were included in the study. In all, 260 Astra Tech TiOblast? implants (Astra Tech AB, Mölndal, Sweden) were installed. Twenty‐five of these patients had severe maxillary atrophy and were treated with iliac bone grafts 5 to 6 months prior to implant placement, 19 with lateral onlay block grafts on one side (group A, 38 implants) and particulate bone for lateral augmentation on the other (group B, 38 implants). These 19 patients also got bilateral sinus floor augmentation with particulate bone (group C, 76 implants). Six patients had an unfavorable sagittal relation between the jaws and underwent a LeFort I operation with interpositional bone blocks grafted to the nasal and sinus floors (group D, 48 implants). The remaining 10 patients could be treated with implants without bone augmentation and served as control (group E, 60 implants). RFA was performed at implant placement and abutment connection 6 months later and an implant stability quotient (ISQ) value was given for each implant. Results: Four implants (1.5%) were found mobile at abutment connection and removed (two in group A and two in group D). RFA showed a slight increase in stability from installation to abutment connection but the differences were not statistically significant in any of the groups (Wilcoxon signed rank test for comparison of paired data). Implants installed in group D had a significantly lower ISQ value at both measurements compared with the other groups (Wilcoxon Rank Sum test for comparisons of independent samples, p = .05). Conclusion: It is concluded that TiO₂‐blasted implants placed in nongrafted and grafted maxillary bone using a two‐staged protocol show similar stability during the early phase of osseointegration. Patients reconstructed with interpositional bone graft after a LeFort I osteotomy showed lower implant stability values than nongrafted patients and other grafting techniques.     

Recombinant human bone morphogenetic protein-7 in maxillary sinus floor elevation surgery in 3 patients compared to autogenous bone grafts. A clinical pilot study

BACKGROUND/AIMS: This pilot study was designed to determine the clinical bone formation ability of a human recombinant DNA bone morphogenetic protein-7, also referred to as Osteogenic Protein-1 [OP-1] combined with a collagen carrier, implanted in the maxillary sinus of 3 patients. The results were compared with a group of 3 patients treated with sinus floor elevation and autogenous bone grafts. METHODS: 6 consecutive patients, 4 female and 2 male, between 48 and 57 years of age were treated by means of sinus floor elevation for insufficient bone height in the posterior maxilla for implant surgery. 3 patients, 2 female and 1 male, were treated with OP-1 attached to a collagen device. In these patients, 4 maxillary sinus grafting procedures according to Tatum's method were carried out. 1 g of collagen carrier containing 2.5 mg rhOP-1 mixed with 3 ml of saline was placed between the bony floor and the elevated mucosal lining of the most caudal part of the maxillary sinus, in order to increase the vertical bone dimension to place dental implants of a sufficient length. The 3 other patients, also 2 female and 1 male, with a total of 5 sinus sites, were treated with sinus floor elevation and autogenous iliac crest bone grafts. After 6 months, during dental implant preparation, bone cores were taken for histology. Thus, clinical, radiological and histological results of the 2 groups of 3 patients were compared. RESULTS: 6 months after sinus grafting with OP-1, in 1 male, well-vascularized bone-like tissue of good quality was observed clinically. This could be confirmed by histology. In the second, female, patient no bone formation was observed at all. A cyst-like granular tissue mass, without purulent content, was removed. In the 3rd, female, patient, who received bilateral sinus grafts, some bone-like formation was seen, however it showed flexible tissue which led to the decision that at 6 months after the sinus grafting, the implant placement had to be postponed. In all 5 autogenous grafted sinuses a bone appearance similar to normal maxillary bone was observed clinically as well as histologically and dental implants could be placed six months after sinus floor elevation surgery. CONCLUSIONS: These findings indicate that the OP-1 device has the potential for initiating bone formation in the human maxillary sinus within 6 months after a sinus floor elevation operation. However, the various findings in these 3 patients indicate that the behaviour of the material is at this moment insufficiently predictable, in this indication area. Further investigation is indicated before OP-1 can be successfully used instead of the "gold standard" autogenous bone graft.     

A collagenated porcine bone substitute for augmentation at Neoss implant sites: a prospective 1-year multicenter case series study with histology

Background: The presence of localized defects and/or small amounts of bone below the maxillary sinus is a common finding, which may compromise implant placement. There is therefore a need for predictable techniques for bone augmentation in such situations. Purpose: The study aims to clinically and histologically evaluate a porcine bone (PB) substitute used for augmentation of the alveolar crest or the maxillary sinus floor prior to or in conjunction with implant placement. Materials and Methods: Nineteen patients were treated with a porcine bone substitute and barrier membranes (OsteoBiol, Tecnoss Dental, Turin, Italy) for lateral bone augmentation (Group 1a) and healing of bone defects (Group 1b) or for augmentation of the maxillary sinus floor using either a replaceable (Group 2a) or an infractured bone window (Group 2b). A total of 34 implants (Neoss Ltd., Harrogate, UK) were placed in conjunction or 5 to 7 months after the procedure. Implants were followed with implant stability measurements at placement and abutment connection, and with intraoral radiographs at abutment connection and after at least 1 year of loading. A biopsy for histology and morphometry was taken at the first reentry operation. Results: All but one of the procedures was successful (94.7%) as one maxillary sinus procedure (Group 2a) resulted in insufficient bone for implant placement. One of the 34 implants failed, giving an implant survival rate of 97.1% after 1 year. Implant stability measurements showed a mean stability of 71.9 ± 7.7 implant stability quotient (ISQ) at placement, which significantly increased to 75.3 ± 6.8 ISQ at abutment connection (p = .03). The average bone loss was 0.5 ± 0.7 mm during 1 year. Histology revealed new bone formation at the PB surface, which formed bridges between particles and between particles and preexisting bone. The presence of scalloped resorption lacunae and new osteons inside the particles indicated ongoing resorption/remodeling of the particles. The histomorphometric analyses showed that the total specimen area consisted of, in average, 56.5 ± 15.7% mineralized tissue of which 24.8 ± 13.9% of the total area was PB particles. Conclusion: This study showed good clinical results when using a PB substitute and barrier membranes for augmentation of the alveolar crest and maxillary sinus. Histology revealed bone condensation properties and indicated that the material can be resorbed with time.     

自体植骨上颌窦底提升同期种植体植入术近期疗效观察

目的:评价自体骨开窗式上颌窦提升术对上颌后牙区牙槽骨高度严重不足(高度4～6mm)的患者种植治疗的近期疗效。方法:对4例上颌后牙骨量不足(高度4～6mm)而需种植修复的病例,实施自体植骨的开窗式上颌窦提升术,并同期植入种植体共9枚。自体移植骨来自种植窝制备时中空钻取骨,在需做牙槽嵴修整处的牙槽骨棘取骨,如不够再用刮骨器取骨或从颏部手术取骨,将所取之骨碾碎备用。结果:术后7个月拍片,均显示骨性愈合;冠修复后行使功能18～24个月效果理想。结论:自体取骨植骨用于上颌窦提升,可扩大种植手术适应证,降低种植成本。     

Bone quality after sinus floor augmentation

The problem of insufficient alveolar bone in the edentulous maxilla caused by resorption and pneumatization can be overcome by augmentation of the sinus floor to increase bone volume for the placement of dental implants. The quality of bone which is achieved after sinus floor augmentation is hardly known. This study describes the histologic results obtained three till six months after sinus floor augmentation with autogenous bone from the iliac crest in patients with severe maxillary bone resorption. The bone biopsies taken from the implant sites showed a substantial bone volume with a mature trabecular pattern and active bone growth. It was concluded that with the obtained bone quality, the sinus floor augmentation procedure can be a good treatment modality for the rehabilitation with implants in patients with severe maxillary bone atrophy.     

Dental implant treatment with different techniques for sinus floor elevation--a case report

A 60-year-old man with missing maxillary molar teeth received dental implant therapy for reconstruction of occlusion. Sinus floor elevation with autogenous bone graft consisting of iliac bone block and particulate cancellous bone and marrow (PCBM) was performed in the bilateral maxillary sinuses for implant placement. On the right side, bone height in the molar region was less than 2mm. Therefore, a delayed protocol was applied, and 2 implants were placed 4 months after bone grafting. Bone graft resorption occurred during the healing period of 4 months. On the left side, 3 implants were placed simultaneously with sinus floor elevation, as bone height in the molar region was more than 4-5mm. The bone graft was carried out at the same time as implant placement. After implant placement, resorption of the bone graft stopped, and the superstructures were delivered on both sides. The tissues around the implants were clinically healthy at one year after examination. Sinus floor elevation with autogenous bone graft is an acceptable option for implant treatment in the maxillary molar region where there is adequate height of existing bone. In postoperative care, it is important to undertake adequate follow-up to ascertain occurrence of bone graft resorption.     

Maxillary sinus augmentation: histologic and histomorphometric analysis

PURPOSE: Implant placement in the posterior maxilla may often be contraindicated because of insufficient bone volume and the presence of the maxillary sinus. In these situations, sinus floor lifting and grafting frequently have been proposed as the best treatment. The aim of this study was to compare histologically the use of 100% autogenous bone versus a combination of autogenous bone and corticocancellous pig bone for maxillary sinus augmentation. MATERIALS AND METHODS: Eighteen patients requiring bilateral maxillary sinus augmentation were selected for this study. Bone for grafting was harvested from the iliac crest. Each patient received 100% autogenous bone in 1 randomly selected sinus (control side) and a 1:1 mixture of autogenous bone and corticocancellous pig bone particles in the contralateral sinus (test side). Five months after the augmentation procedure, bone biopsy specimens were taken at the time of implant placement. RESULTS: No complications were observed during the surgical procedures; all patients healed uneventfully. No signs or symptoms of maxillary sinus disease were observed during the 5 months after surgery. No significant differences in bone percentages were observed in the bone biopsies from test and control sides. DISCUSSION AND CONCLUSION: It could be concluded from this study that corticocancellous pig bone particles can be successfully used in a 1:1 mixture with autogenous bone from the iliac crest for maxillary sinus augmentation in cases of severely atrophic maxilla.     

Full mouth implant rehabilitation of a patient with ectodermal dysplasia after orthognathic surgery, sinus and ridge augmentation: a clinical report

An 18-year-old male presented severe hypodontia due to hypohidrotic ectodermal dysplasia was treated with Le Fort I maxillary osteotomy with simultaneous sinus floor augmentation using the mixture of cortical autogenous bone graft harvested from iliac crest and organic Bio-Oss to position the maxilla in a right occlusal plane with respect to the mandible, and to construct adequate bone volume at posterior maxilla allowing proper implant placement. Due to the poor bone quality at other sites, ridge augmentation with onlay graft was done to construct adequate bone volume allowing proper implant placement, using tissue harvested from the iliac bone. Seven implants were placed in the maxilla and 7 implants were inserted in the mandible and screw-retained metal ceramic FPDs were fabricated. The two year follow up data showed that dental implants should be considered as a good treatment modality for patients with ectodermal dysplasia.     

Histologic evaluation of autogenous calvarial bone in maxillary onlay bone grafts: a report of 2 cases

Bone augmentation for implant dentistry has become a necessary procedure for a number of edentulous patients. Calvarial bone grafting constitutes an important tool in achieving maxillary augmentation and sinus elevation. Much effort has been directed toward improving graft survival and volumetric maintenance. The purpose of the present study was to evaluate the histologic results of the calvarial onlay graft for maxillary reconstruction before implant placement. Two patients underwent maxillary augmentation using autogenous calvarial onlay grafts. After a 4-month healing period, biopsies of the augmented regions were performed and implants were placed. The implants were loaded after 5 months and then clinically examined after 15 months of function. Biopsies showed that calvarial onlay grafts were well incorporated into the preexisting bone after a 4-month period. Histologic and histomorphometric findings demonstrated a living bone that showed features characteristic of mature and compact osseous tissue. The restored Implants were stable and osseointegrated after a 15-month period of follow-up. The use of calvarial onlay grafts can be a predictable and successful method to achieve maxillary augmentation, allowing appropriate placement of implants and stable prosthetic restorations.     

Clinical results of alveolar ridge augmentation with mandibular block bone grafts in partially edentulous patients prior to implant placement

A group of 15 partially edentulous patients who needed alveolar ridge augmentation for implant placement, were consecutively treated using a two-stage technique in an outpatient environment. A total of 18 alveolar segments were grafted. During the first operation bone blocks harvested from the mandibular ramus or symphysis were placed as lateral or vertical onlay grafts and fixed with titanium osteosynthesis screws after exposure of the deficient alveolar ridge. After 6 months of healing the flap was re-opened, the screws were removed and the implants placed. Twelve months after the first operation implant-supported fixed bridges could be provided to the patients. Mean lateral augmentation obtained at the time of bone grafting was 6.5 +/- 0.33 mm, that reduced during healing because of graft resorption to a mean of 5.0 +/- 0.23 mm. Mean vertical augmentation obtained in the 9 sites where it was needed was 3.4 +/- 0.66 mm at bone grafting and 2.2 +/- 0.66 mm at implant placement. Mean lateral and vertical augmentation decreased by 23.5% and 42%, respectively, during bone graft healing (before implant insertion). Mandibular sites showed a larger amount of bone graft resorption than maxillary sites. All the 40 implants placed were integrated at the abutment connection and after prosthetic loading (mean follow-up was 12 months). No major complications were recorded at donor or recipient sites. Soft tissue healing was uneventful, and pain and swelling were comparable to usual dentoalveolar procedures. A visible ecchymosis was present for 4 to 7 days when the bone was harvested from the mandibular symphysis. From a clinical point of view this procedure appears to be simple, safe and effective for treating localised alveolar ridge defects in partially edentulous patients.     

Clinical and histologic comparison of two different composite grafts for sinus augmentation: a pilot clinical trial

Background and objectives: Sinus augmentation is a procedure used for augmenting insufficient bone height that is often observed in the maxillary posterior areas. Many different techniques as well as bone graft regimens have been suggested for performing this procedure. It was the goal of this study to compare, clinically and histologically, two different composite grafting regimens used for sinus augmentation.
Material and methods: Five patients, needing a bilateral sinus augmentation to allow implant placement, were recruited for this study. Right sinuses were grafted with cortical bone (collected from overlying the sinus membrane) and bovine hydroxyapatite (HA), while the left side sinuses were grafted with overlying autologous bone plus a bioglass (BG) material. Bone core biopsies were taken at 6 months after sinus graft or at the time of implant insertion. A waiting period of 6 additional months was granted to allow healing, before prosthetic restoration and functional loading. The level of peri-implant bone was evaluated 12 months after loading. A comparative histomorphometric analysis was conducted and a statistical analysis was performed.
Results: All implants in both groups were functional after a 12-month loading period. No bone loss was observed radiographically or clinically in both groups. Histologic analysis revealed that both composite grafts had a high biocompatibility. In the bovine HA-containing group, minimal xenogenic graft absorption was noted. In contrast, BG group samples presented a high absorption rate with some remaining particles imbedded in new normal bone.
Conclusions: Sinus augmentation using a combination of autogenous bone plus either bovine HA or BG is a predictable technique.     

Histologic analysis of clinical biopsies taken 6 months and 3 years after maxillary sinus floor augmentation with 80% bovine hydroxyapatite and 20% autogenous bone mixed with fibrin glue

Background: Bovine hydroxyapatite (Bio‐Oss®, Geistlich Pharmaceutical, Wollhausen, Switzerland) has been suggested to be used in maxillary sinus floor augmentation procedures prior to or in conjunction with implant placement. However, the long‐term histologic fate of this material is not well understood. Purpose: The aim with this study was to histologically evaluate the tissue response in patients to a mixture of bovine hydroxyapatite (BH), autogenous bone, and fibrin glue 6 months and 3 years after a maxillary sinus floor augmentation procedure. Materials and Method: Biopsies were taken from a group of 20 consecutive patients 6 months (n = 16) and 3 years (n = 12) after maxillary sinus floor augmentation with a mixture of BH (80%), autogenous bone (20%), and fibrin glue and prepared for histologic analysis. Results: Light microscopy and morphometry from biopsies taken after 6 months showed various amounts of mineralized bone tissue. The specimen area was occupied by 54.1 ± 12.6% nonmineralized tissue, followed by 21.2 ± 24.5% lamellar bone, 14.5 ± 10.3% BH particles, and 10.2 ± 13.4% woven bone. The nonmineralized tissue seen in bone‐forming areas consisted of a loose connective tissue, rich with vessels and cells. There were no signs of resorption of the BH particles. The lamellar bone appeared to have originated from the recipient site and was seldom in contact with the BH particles. After 3 years, the nonmineralized tissue area had decreased to 36.0 ± 19.0% (p > .05) and consisted mainly of bone marrow tissue. The surface area of lamellar bone had increased to 50.7 ± 22.8% (p > .05), and there was almost no immature bone. The mean specimen area occupied by BH particles, was 12.4 ± 8.7% and had not changed from 6 months (not significant). Moreover, the sizes of the particles were similar after 6 months and 3 years. The degree of BH particle–bone contact had increased from 28.8%± 19.9% after 6 months to 54.5 ± 28.8% after 3 years (p > .05). Conclusion: Histology of specimens from maxillary sinuses augmented with 80% BH particles, 20% autogenous bone, and fibrin glue showed a positive bone tissue response after 6 months and 3 years after augmentation of the maxillary sinus floor prior to implant placement in a group fo 20 patients. The bone surrounding and in contact with the BH particles after 6 months was mainly immature woven bone, which with time was replaced by mature lamellar bone filling the interparticle space as observed in the 3‐year specimens. Moreover, bone‐integrated BH particles seem to be resistant to resorption. The results indicate that the procedure may be considered when only small amounts of intraoral autogenous bone graft are available.