Human Maxillary Sinuses Augmented With Mineralized, Solvent-Dehydrated Bone Allograft: A Longitudinal Case Series

CBCT for Diagnostics, Treatment Planning and Monitoring of Sinus Floor Elevation Procedures

Sinus floor elevation (SFE) is a standard surgical technique used to compensate for alveolar bone resorption in the posterior maxilla. Such a surgical procedure requires radiographic imaging pre- and postoperatively for diagnosis, treatment planning, and outcome assessment. Cone beam computed tomography (CBCT) has become a well-established imaging modality in the dentomaxillofacial region. The following narrative review is aimed to provide clinicians with an overview of the role of three-dimensional (3D) CBCT imaging for diagnostics, treatment planning, and postoperative monitoring of SFE procedures. CBCT imaging prior to SFE provides surgeons with a more detailed view of the surgical site, allows for the detection of potential pathologies three-dimensionally, and helps to virtually plan the procedure more precisely while reducing patient morbidity. In addition, it serves as a useful follow-up tool for assessing sinus and bone graft changes. Meanwhile, using CBCT imaging has to be standardized and justified based on the recognized diagnostic imaging guidelines, taking into account both the technical and clinical considerations. Future studies are recommended to incorporate artificial intelligence-based solutions for automating and standardizing the diagnostic and decision-making process in the context of SFE procedures to further improve the standards of patient care.

Bone augmentation by replica-based bone formation

OBJECTIVE

The sources of iliac crest bone grafts are limited. Alternatives are evaluated due to the progress in biomaterial sciences. Synthetical hydroxyapatite (HA), ß-tricalcium phosphate (ß-TCP) or biphasic compounds, or even a mélange of HA and ß-TCP will replace bovine ceramics. The goal is maintenance of replica-based-bone formation (RBBF) for bone augmentation.

METHODS

2 female and 2 male patients between 41 and 73 years with 5 sinus elevations were evaluated. Sinus elevations with lateral fenestration, trapezoidal-muco-periosteal flaps and filling with micro-chambered beads (1.5 mm) was performed. A porcine-collagenous membrane and the refixated flap covered the defect. A biopsy program over 20 months was confirm confirm the maintenance of the newly formed bone.

RESULTS

A fast bone formation was pronounced. The biopsies revealed mature lamellar bone and full osseointegration of the ß-TCP implant. The biopsy after 20 months showed compact bone with osseointegration of minor rests of the ceramic implant. The defect revealed a mature bone stock already after 5 weeks.

SIGNIFICANCE

The introduction of the replica-based-bone formation (RBBF) around micro-chambered beads will change the paradigm of bone augmentation. The next step of the ongoing study has to redefine the interval for implant insertion. The clinical approach confirms the breakthrough to primary mature lamellar bone formation and will permit reduction of placement time for a dental implant.

Vertical Guided Bone Regeneration with Mineralized Cancellous Bone Allograft in a Severe Anterior Maxillary Defect: A Clinical Report with 14-Year Follow-Up

Purpose

To report the supracrestal bone regeneration of approximately 10 mm using solvent-dehydrated mineralized cancellous bone allograft and nonresorbable membrane in rehabilitation of unsuccessful implants in the anterior maxilla and stability of the regenerated bone at the 14th-year follow-up.

Case Presentation

A 24-year-old female patient with a history of anterior dentoalveolar trauma resulting in the loss of upper left incisors and canine underwent rehabilitation several years ago with three implant-supported fixed prostheses. The prosthesis was both functionally and aesthetically inadequate, and the patient complained of gingival swelling, bleeding, and food impaction at the site of the implants. A staged approach for retreatment was planned, wherein the first surgical stage aimed at removing the existing implants and preparing the bone ridge and soft tissues for the augmentation procedure. The second stage was vertical ridge augmentation and simultaneous prosthetic-driven placement of two new implants at the sites of the left central incisor and canine. After nine months of uneventful healing, complete regeneration of the bony defect was achieved, and the new prosthetic rehabilitation satisfied both functional and aesthetic requirements.

Conclusion

The therapeutic approach followed in the present case proved effective in achieving satisfactory functional and aesthetic results and in maintaining the stability of the regenerated bone at 14 years of follow-up.

Radiological and Histomorphometric Outcomes of Homologous Bone Graft in Postextractive Implant Sites: A 6-Year Retrospective Analysis

OBJECTIVES

The aim was to investigate the in vivo efficacy of a cancellous particulate allograft bone in the regeneration of postextractive atrophic sites.

MATERIAL AND METHODS

Ten patients were selected, and after a minimally invasive extraction of the teeth (T0), a cone beam computed tomography was performed (T1). Seven days after extraction, Puros cancellous particulate homologous graft was inserted into the elected sites together with a membrane (T2). After 4 months, a cone beam computed tomography of the sites was performed (T3). After 5 months, samples of the regenerated sites were taken contextually to implant insertion (T4). The samples were histologically and histomorphometrically analyzed. Intraoral periapical radiographs were accomplished at T4 and at the 6-year follow-up appointment (T5).

RESULTS

The mean vertical bone augmentation was of 4.1 mm in the lower jaw and of 3.35 mm in the maxilla at T3 appointment. The mean horizontal bone augmentation in the lower jaw was 2.02 and 2.15 mm in the maxilla. At T4, the mean total bone was 60.01% and the mature bone was 98.41. At the 6-year follow-up visit, the mean periimplant bone resorption was 0.14 mm (range 0-0.5 mm).

CONCLUSIONS

Cancellous particulate allograft bone demonstrated excellent bone regeneration behavior both in terms of quantity and quality, and stable results over a 6-year period.

CLINICAL RELEVANCE

Cancellous allograft bone can be successfully used to regenerate atrophic sites.

Maxillary Sinus Augmentation With Calcium Phosphate Double-Coated Anorganic Bovine Bone: Comparative Multicenter Randomized Clinical Trial With Histological and Radiographic Evaluation

PURPOSE

The purpose of this study was to evaluate the clinical, histological and radiographic outcomes of the calcium phosphate double-coated anorganic bovine bone (InduCera; Oscotec Inc., Seongnam, Gyeonggi, Republic of Korea) compared with that of anorganic bovine bone (Bio-Oss; Geistlich Biomaterials, Wolhusen, Switzerland) in maxillary sinus augmentation, prospectively.

PATIENTS AND METHODS

Twenty-eight sinuses in 25 patients (3 bilateral) with vertical alveolar bone height from 2 to 5 mm were included in this study. The maxillary sinus was augmented with InduCera or Bio-Oss, followed by a healing period of 6 months. Trephine cores were obtained for histomorphometric evaluation with the implant placement. Cone-beam computed tomography (CBCT) scans were taken at 1 week and 6 months after sinus augmentation.

RESULTS

The graft sites were healed without any notable complications in both groups. In histomorphometric analysis, the area of the newly formed bone was measured as 21.37 ± 8.87% for InduCera and 23.02 ± 5.88% for Bio-Oss, with no significant differences. Radiographically, no statistically significant differences were calculated between the groups in bone height at baseline, the height of bone augmentation, the final alveolar bone height (alveolar bone height + augmented height) after 6 months in panoramic radiograph. There were also no significant differences in the shrinkage rate of the grafted area volume in CBCT.

CONCLUSION

Although calcium phosphate double-coated anorganic bovine bone showed no additional effect compared with anorganic bovine bone from a histological and radiographical point of view, it could be used as the bone graft material in maxillary sinus augmentation.

Comparative Histological and Histomorphometric Results of Six Biomaterials Used in Two-Stage Maxillary Sinus Augmentation Model after 6-Month Healing

Objectives

To evaluate the performances of six different bone substitute materials used as graft in maxillary sinus augmentation by means of histological and histomorphometric analysis of bone biopsies retrieved from human subjects after a 6-month healing period.

Materials and Methods

Six consecutive patients (3 males, 3 females, aged 50-72 years), healthy, nonsmokers, and with good oral hygiene, presenting edentulous posterior maxilla with a residual bone crest measuring ≤ 4 mm in vertical height and 3 to 5 mm in horizontal thickness at radiographic examination, were selected to receive sinus augmentation and delayed implant placement. Under randomized conditions, sinus augmentation procedures were carried out using mineralized solvent-dehydrated bone allograft (MCBA), freeze-dried mineralized bone allograft (FDBA), anorganic bovine bone (ABB), equine-derived bone (EB), synthetic micro-macroporous biphasic calcium-phosphate block consisting of 70% beta-tricalcium phosphate and 30% hydroxyapatite (HA-β-TCP 30/70), or bioapatite-collagen (BC). After 6 months, bone core biopsies were retrieved and 13 implants were placed. Bone samples were processed for histological and histomorphometric analysis. CT scans were taken before and after surgery. After 4 months of healing, patients were restored with a provisional fixed acrylic resin prosthesis, as well as after further 2-4 months with a definitive cemented zirconia or porcelain-fused-to-metal crowns.

Results

There were no postoperative complications or implant failures. The histological examination showed that all biomaterials were in close contact with newly formed bone, surrounding the graft granules with a bridge-like network. No signs of acute inflammation were observed. The histomorphometry revealed 20.1% newly formed bone for MCBA, 32.1% for FDBA, 16.1% for ABB, 22.8% for EB, 20.3% for HA-β-TCP 30/70, and 21.4% for BC.

Conclusions

Within the limitations of the present investigation, all the six tested biomaterials showed good biocompatibility and osteoconductive properties when used in sinus augmentation procedures, although the FDBA seemed to have a better histomorphometric result in terms of newly formed bone and residual graft material. This trial is registered with ClinicalTrials.gov Identifier (Registration Number): NCT03496688.

Clinical efficacy of grafting materials in alveolar ridge augmentation: A systematic review

PURPOSE

To evaluate the efficacy of grafting materials in lateral and vertical ridge augmentations.

MATERIALS AND METHODS

A systematic review of the literature on the clinical use of grafting materials of the years 1995 to April 2015 was conducted using electronic search of PubMed and Cochrane libraries and hand search of eight print journals. A total of 184 papers were included, comprising 6182 patients. Parameters evaluated were observation period [months], bone formation [histologic area%], defect fill [%], horizontal and vertical gain [mm], loss of augmented volume [mm], complication rate [%], and implant survival rate [%]. Results are expressed as weighted means ± SD.

RESULTS

Results were obtained after a weighted mean observation period of 27.4 months (range 3-168 months). Bone formation in the augmented areas varied from 33.2 ± 14.9% for allogeneic grafts to 56.0 ± 25.6% for mixtures of autogenous and other grafting materials. Defect fill in dehiscence defects ranged from 51.0 ± 13.6% (synthetic) to 85.8 ± 13.4% (xenogeneic) for the different materials, with an overall weighted mean of 79.8 ± 18.7%. Weighted mean horizontal gain for all particulate grafting materials was 3.7 ± 1.2 mm, with variation between 2.2 ± 1.2 mm (synthetic) and 4.5 ± 1.0 mm (mixtures of autogenous bone with allogeneic/xenogeneic grafting material) without statistical significance. Weighted overall mean vertical gain was 3.7 ± 1.4 mm. Vertical gain was substantially higher when space-making barrier materials such as titanium meshes were used; however this was also associated with strong increase in complication rate. Block grafts achieved higher horizontal gain by approximately 1 mm. The use of block grafts achieved significantly increased vertical gain compared to particulate material only when autogenous block grafts from extraoral donor sites were used.

CONCLUSION

Horizontal and vertical gain by 3.7 mm on average can be achieved using particulate materials. This can be increased by using titanium meshes. Substantial vertical gains beyond this dimension require the use of extraoral bone block grafts.

Histological and Histomorphometric Human Results of HA-Beta-TCP 30/70 Compared to Three Different Biomaterials in Maxillary Sinus Augmentation at 6 Months: A Preliminary Report

OBJECTIVE

The aim of this investigation was to examine the bone regenerative potential of newly biphasic calcium phosphate ceramics (HA-β-TCP 30/70), by assessing histological and histomorphometric results of human specimens retrieved from sinuses augmented with HA-β-TCP 30/70, and comparing them to anorganic bovine bone (ABB), mineralized solvent-dehydrated bone allograft (MSDBA), and equine bone (EB), after a healing period of 6 months.

MATERIALS AND METHODS

Four consecutive patients with edentulous atrophic posterior maxilla were included in this report. A two-stage procedure was carried out for sinus augmentation with HA-β-TCP 30/70, ABB, MSDBA, and EB. After 6 months, specimens were retrieved at the time of implant placement and processed for histological and histomorphometric analyses.

RESULTS

At histological examination, all biomaterials were in close contact with the newly formed bone and showed the same pattern of bone formation; the grafted granules were surrounded by a bridge-like network of newly formed bone. A limited number of ABB particles were partially covered by connective tissue. The histomorphometric analysis revealed 30.2% newly formed bone for Ha-β-TCP 30/70, 20.1% for ABB, 16.4% for MSDBA, and 21.9% for EB.

CONCLUSIONS

Within the limitations of the present investigation, these results support the successful use of HA-β-TCP 30/70 for sinus augmentation.

Fresh-frozen allografts combined with bovine bone mineral enhance bone formation in sinus augmentation

We evaluated histologically, histomorphometrically, and tomographically the effects of the association of fresh-frozen bone allograft (FFB) with bovine bone mineral (BBM) in maxillary sinus floor augmentation. In total, 34 maxillary sinuses from 29 patients, with a mean age of 51.32 (±6.44) years, underwent sinus augmentation. Patients were divided into control and test groups (17 sinuses each). The controls were grafted with allograft bone, and the test group received a combination of FFB and BBM at a 2:1 ratio. After 6 months, bone samples were collected for histological and histomorphometric examinations. The implant survival rates were 93.02% (control group) and 100% (test group) at 6 months after functional loading. Median volumetric reductions of 28.32% (17.05-44.05) and 12.62% (5.65-16.87) were observed for the control and test groups, respectively. Statistically significant histomorphometric differences were found between the control and test groups regarding newly formed bone 12.54% (10.50-13.33) vs. 24.42% (17.62-35.92), p < 0.001, total bone 48.34% (39.03-54.42) vs. 61.32% (50.61-64.96), p = 0.007, and connective tissue 51.66% (45.57-60.97) vs. 39.30% (35.03-49.37), p = 0.007. The addition of BBM to allograft bone in maxillary sinus augmentation resulted in higher percentages of new bone formation and total bone, and permitted implant placement with a low rate of osseointegration failure at the 6-month follow-up.