Histopathological morphometric evaluation of 2 different hydroxyapatite-bone derivatives in sinus augmentation procedures: a comparative study in humans

A randomized clinical trial of phycogenic materials for sinus grafting with hydroxyapatite versus biphasic calcium phosphate: 2 years clinical outcomes

OBJECTIVES

To assess in a prospective randomized trial two phycogenic bone substitutes-biphasic calcium phosphate (BCP) versus almost pure hydroxyapatite (HA)-for their volume stability and clinical implications after sinus floor elevation (SFE).

MATERIALS AND METHODS

Twenty patients requiring lateral-window SFE 6 months prior to implant surgery were randomized to a BCP or HA group. As primary outcome, the grafts were analyzed for volume stability, using four cone-beam computed tomography scans obtained immediately/6/12/24 months after SFE. Secondary outcomes were implant survivval, success, periotest values, oral-health-related quality of life (OHIP-G14), and pain (VAS).

RESULTS

Kolmogorov-Smirnov goodness-of-fit test revealed normal distribution of samples (p = .200). At 6/12/24 months, the augmented volumes decreased to 96/92/90% (HA) or 99/96/96% (BCP). Volume changes were significantly a factor of time (p < .001; generalized linear model with repeated measures) and reached significantly lower values in HA group (p = .018). Significant intergroup difference in volume losses was notable at 24 months (p = .021; t-test for independent samples). Periotest values decreased from -3/-4.1 (HA/BCP) after implant placement to -6.3/-4.5 (HA/BCP) after 6 months. OHIP scores diverged at 2 months (HA: 9.5; BCP: 5.2) and largely resolved by 24 months (HA: 1.3; BCP: 1.9). VAS scores were comparable, 2.2 at 1 week after SFE being their highest mean level.

CONCLUSIONS

After 2 years, both groups experienced no biological or technical complications, demonstrating a consistent healing trajectory without notable symptoms. Although no significant differences were observed in implant stability and survival, BCP demonstrated higher volume stability than HA.

A Histologic, Histomorphometric, and Immunohistochemical Evaluation of Anorganic Bovine Bone and Injectable Biphasic Calcium Phosphate in Humans: A Randomized Clinical Trial

Following trauma, chronic periapical process, or tooth extraction, a large loss of bone volume is noticed during the healing process. To facilitate the placement of dental implants, various surgical procedures are used for an optimal alveolar ridge profile, while maintaining adequate bone dimensions. The main aim of this study was to determine the healing ability (histologically and immunohistologically) of alveolar bone defects during augmentation with two different biomaterials: injectable biphasic calcium phosphate (BCP) and anorganic bovine bone (ABB). Thirty-eight subjects were randomly divided into two groups. The first group received the tested bone substitute biomaterial (BSB), i.e., BCP (maxresorb inject®), and the second group received an alternative to the gold standard, i.e., ABB (Bio-Oss®). The histopathological, histomorphometric, and immunohistochemical analyses gave comparable results for these bone substitute materials in terms of newly formed bone: (BCP: 39.91 ± 8.49%, ABB: 41.73 ± 13.99%), residual biomaterial (BCP: 28.61 ± 11.38%, ABB: 31.72 ± 15.52%), and soft tissue (BCP: 31.49 ± 11.09%, ABB: 26.54 ± 7.25%), with no significant difference found between the groups (p < 0.05, t-test), proving that BCP is equally suitable and successful for alveolar bone regeneration.

Sinus augmentation procedure via the lateral window technique-Reducing invasiveness and preventing complications: A narrative review

Sinus augmentation has become an integrated surgical phase in posterior maxillary implant prosthesis reconstruction. Since the residual alveolar bony height usually requires additional volume particularly at this anatomical region, sinus floor augmentation is advocated routinely. Over the years, Implant success rate is proved to be comparable to the one in the pristine bone, which is well documented in the literature. Anatomical aspects as well as surgeon skills are at most importance to achieve predictable outcome. In this narrative review, the different osteotomy techniques, the indications toward 1 or 2-stage approaches, the control of the Schneiderian membrane integrity as well as the management of intra- and post-operative complications are thoroughly discussed according the current data. In light of the excellent long-term implant success rate concurrent with the application of contemporary advanced techniques of the sinus augmentation via the lateral wall osteotomy approach, reduce invasiveness and less complication occurrences are well documented. A well-codified patient selection involving the rhinologist as an integral medical team would be significantly beneficial toward early diagnosis. In-depth knowledge of the anatomy, execution of a well standardized surgical technique, and understanding the complication etiology and their management are prerequisites for reducing patient morbidity to minimal discomfort and predictable successful outcome.

Grafting biomaterials associated to topical glucocorticoid: effects on pre-osteoblastic cells (MC3T3-E1)

The topical glucocorticoid budesonide has been prescribed before and after sinus lift surgery as adjuvant drug treatment for maxillary sinus membrane inflammation. However, there is no study on the effects of budesonide on the regenerative process of bone grafting biomaterials. We investigated the effect of the association of budesonide with some biomaterials on the growth and differentiation capacity of pre-osteoblastic cells (MC3T3-E1 subclone 4). Xenogeneic (Bio-Oss and Bio-Gen) and synthetic hydroxyapatites (Osteogen, Bonesynth, and HAP-91) were tested in conditioned medium (1% w/v). The conditioned medium was then supplemented with budesonide (0.5% v/v). Cell viability was assessed using the MTT assay (48, 96, and 144 h), and mineralized nodules were quantified after 14 days of culture using the Alizarin Red Staining. Alkaline phosphatase activity was assessed through the release of thymolphthalein at day seven. All biomaterials showed little or no cytotoxicity. The Bio-Gen allowed significantly less growth than the control group regardless of the experimental time. Regarding differentiation potential of MC3T3-E1, the HAP-91-conditioned medium showed remarkable osteoinductive properties. In osteodifferentiation, the addition of budesonide favored the formation of mineral nodules when cells were cultured in medium conditioned with synthetic materials, whereas it weakened the mineralization potential of cells cultured in xenogeneic medium. Regardless of whether budesonide was added or not, Osteogen and Bio-Oss showed higher alkaline phosphatase activity than the other groups. Budesonide may improve bone formation when associated with synthetic biomaterials. Conversely, the presence of this glucocorticoid weakens the mineralization potential of pre-osteoblastic cells cultured with xenogeneic hydroxyapatites.

Remodelling of sinus bone grafts according to the distance from the native bone: A histomorphometric analysis

OBJECTIVES

To evaluate graft remodelling according to the distance from the native bone in maxillary sinuses grafted with anorganic bovine bone (ABB).

MATERIAL AND METHODS

Bilateral sinus grafting was performed in twenty patients with residual bone height <5 mm before implant placement. After 8 months, biopsy samples were harvested, and histomorphometric analysis was performed to examine bone formation according to the distance (in mm) from the native bone (sinus floor). In the grafted area, the percentages of new bone (NB), residual graft material (rABB), and soft tissue (ST) were evaluated.

RESULTS

A total of 103 biopsy samples were evaluated, and the percentages of NB, rABB, and ST were 31.62 ± 9.85%, 18.94 ± 7.88%, and 49.41 ± 9.52%, respectively, in the 1st mm; 27.15 ± 9.83%, 23.33 ± 9.45%, and 49.53 ± 11.73%, respectively, in the 2nd mm; 23.61 ± 13.02%, 21.35 ± 11.08%, and 55.03 ± 16.14%, respectively, in the 3rd mm; and 21.67 ± 12.29%, 19.67 ± 10.28%, and 58.66 ± 12.46%, respectively, in the 4th mm. The 1st millimetre of the grafted area (closer to the native bone) presented a larger amount of NB than the other portions of the grafted areas and a smaller amount of rABB than the 2nd mm of the grafted area (p < .05). The amount of ST was larger in the 3rd and 4th mm of the grafted area than in the first 2 millimetres (p < .05).

CONCLUSION

The distance from the native bone influences bone formation following maxillary sinus augmentation.

The use of hydroxyapatite bone substitute grafting for alveolar ridge preservation, sinus augmentation, and periodontal bone defect: A systematic review

OBJECTIVES

We determined and structurally analyzed the reported effect of hydroxyapatite (HA) bone substitute on alveolar bone regeneration. To the best of our knowledge, no systematic reviews have previously reported the bone regenerative effect of the HA bone substitute.

MATERIALS AND METHODS

A literature search was performed for articles published up to August 2015 using MEDLINE with the search terms "hydroxyapatite," "bone regeneration," and "alveolar bone" as well as their known synonyms. The inclusion criteria were set up for human trials with at least five patients. The literature search, eligible article selection, and data extraction were independently performed by two readers, and their agreement was reported by κ value.

RESULTS

Of the 504 studies found using the MEDLINE literature search, 241 were included for further steps (inter-reader agreement, κ = 0.968). Abstract screening yielded 74 studies (κ = 0.910), with 42 completely fulfilling the inclusion criteria (κ = 0.864). In a final step, 42 studies were further analyzed, with 17 and 25 studies with and without statistical analysis, respectively. The 17 studies reporting similar outcome measures were compared using the calculated 95% confidence intervals. The effect of HA on ridge preservation could not be evaluated.

CONCLUSIONS

The use of the HA bone substitute interfered with the normal healing process, with significant differences found for sinus augmentation but not for periodontal bone defects. Thus, a bone substitute with optimal bone regenerative properties for alveolar ridge or socket preservation, sinus augmentation, and periodontal bony defect should be developed.

Impact of Inorganic Xenograft on Bone Healing and Osseointegration: An Experimental Study in Rabbits

PURPOSE

To evaluate if an inorganic graft applied before implant insertion interferes with osseointegration.

MATERIALS AND METHODS

The bilateral mandibular incisors of 12 rabbits were extracted. One of the sockets was randomly filled with an inorganic xenogenic bone graft, whereas the remaining socket was allowed to heal naturally and served as a control. After 60 days, titanium implants were inserted into healing areas. The animals were killed 60 days after. Bone depositions were marked with fluorochrome oxytetracycline, alizarin, and calcein and evaluated using confocal laser scanning microscopy. Bone-to-implant contact (BIC) and bone area (BA) within the limits of the implant threads were analyzed. Data were compared statically by paired t tests, one-way ANOVA, and Bonferroni post hoc tests (α = 0.05).

RESULTS

No differences between the control and experimental groups in bone deposition for each marker, in either the BIC or BA analysis were observed. The bone deposition marked by alizarin (14-21 days) was the highest, followed by oxytetracycline (0 and 7 days) and calcein (45 and 52 days) in both groups (P < 0.05).

CONCLUSION

The bone healing or the course of osseointegration was not impaired by the use of an inorganic xenogenic graft before insertion of a titanium implant.

Maxillary Sinus Floor Augmentation With Synthetic Bone Substitutes Compared With Other Grafting Materials: A Systematic Review and Meta-analysis

OBJECTIVE

To test the hypotheses of no differences in implant treatment outcome after maxillary sinus floor augmentation (MSFA) with synthetic bone substitutes (SBS) compared with other grafting materials applying the lateral window technique.

MATERIALS AND METHODS

A MEDLINE/PubMed, Embase and Cochrane Library search in combination with hand-search of selected journals was conducted.

RESULTS

Five randomized controlled trials with low risk of bias fulfilled the inclusion criteria. SBS disclosed high survival rate of suprastructures and implants with no significant differences compared to autogenous bone graft or xenograft. Meta-analysis revealed a patient-based implant survival rate of 0.98 (confidence interval: 0.89-1.08), indicating no differences between SBS and xenograft. SBS demonstrated significant less newly formed bone compared with autogenous bone graft, whereas no significant difference was revealed as compared to xenograft. High implant stability values, limited periimplant marginal bone loss, and few complications were reported with SBS.

CONCLUSIONS

There seem to be no differences in implant treatment outcome after MSFA with SBS compared to other grafting materials.

Subantral Augmentation With Mineralized Cortical Bone Allograft Material: Clinical, Histological, and Histomorphometric Analyses and Graft Volume Assessments

PURPOSE

The aim of this study was to clinically and histologically evaluate the effect of using mineralized cortical bone allograft in sinus lift augmentation and to 3-dimensionally quantify volumetric changes in maxillary sinuses augmented over a 2-year period.

MATERIALS AND METHODS

Eleven patients affected with less than 3 mm of residual ridge were enrolled in the study. After sinus grafting with a mineralized bone allograft, the site was covered with a collagen wound dressing. During implant placement 4 months later, a biopsy was obtained for histological and histomorphometry evaluations. Bone volume changes were also evaluated.

RESULTS

Biopsies showed mature cancellous bone with a predominantly lamellar structure. The well-vascularized intertrabecular spaces were filled with connective tissue and bone marrow. Histomorphometry evaluations revealed a mean 43.76 ± 1.47% of bone marrow, 40.16 ± 1.35% of mineralized bone and 16.59 ± 0.55% of woven bone. The mean of residual particles was 0.47 ± 0.01%. Volumetric measurements showed a mean volume of grafted material 16.24 ± 1.55 cm at T0, 14.48 ± 1.48 cm at T1, and 13.06 ± 1.39 cm at T2. The mean volume retraction was 10.83% of the initial total volume at (T0-T1) and 9.8% at (T1-T2).

CONCLUSIONS

The clinical and histological results indicated that mineralized cortical bone allograft promoted de novo bone formation and can be used for sinus lift procedure.

Implant stability after sinus floor augmentation with deproteinized bovine bone mineral particles of different sizes: a prospective, randomized and controlled split-mouth clinical trial

The aim of this study was to compare implant stability after maxillary sinus floor augmentation using small- or large-sized particles of Bio-Oss. Ten partially edentulous patients requiring bilateral maxillary sinus floor augmentation were enrolled. The subjects were assigned randomly to one of two experimental groups: maxillary sinus was filled with 0.25-1mm particle size (small particles) and the contralateral side was filled with 1-2mm particle size (large particles). After 8 months, a total of 25 implants were placed in the two maxillary sinuses. Primary implant stability was measured immediately after implant placement (T0) using a torque controller and resonance frequency analysis (RFA). Six months after implant placement (T1), the implant stability was measured again. There were no postoperative complications in either particle size group, and the success rate for implant survival was 100%. All implants showed good primary stability as evidenced by high torque for the implant insertion in both groups. RFA revealed high ISQ values for all implants installed in both groups at T0 and T1. These results indicate that the size of the Bio-Oss particles (small and large) did not influence implant stability in the maxillary sinus. Indeed, small and large particles of Bio-Oss presented optimal properties, supporting their possible use as osteoconductive grafts.

Histomorphometric results of different grafting materials and effect of healing time on bone maturation after sinus floor augmentation: a systematic review and meta-analysis

The aim of this systematic review was to evaluate histomorphometric variables, the amount of new bone (NB), residual graft (RG) particles and soft tissue (ST), related to various grafting materials and assess the effect of graft healing time on different histomorphometric outcomes. Studies that were published before October 2015 were electronically and manually searched in three databases. We included human studies that reported the amount of NB, RG and ST in the biopsies taken from the grafted sinuses. Based on the applied grafting materials, extracted data were categorized into different groups. Furthermore, extracted data were classified into three groups based on healing time: (i) ≤ 4.5 mo; (ii) 4.5-9 mo; and (iii) ≥ 9-13.5 mo. The search provided 791 titles. Full text analysis was performed for 258 articles resulting in 136 studies that met the inclusion criteria. Autogenous bone (AB) resulted in the highest amount of NB and lowest amount of RG compared to other grafting materials. Based on this meta-analysis, a significant difference was noticed in the amount of NB formation in grafts with a healing time of > 4.5 mo when compared to the grafts with less healing time. However, when comparing biopsies taken at 4.5-9 mo of healing (average = 6.22 mo) to the ones taken at ≥ 9-13.5 mo (average = 10.36 mo), no significant difference was noticed in the amount of NB formation of various grafts except allografts that resulted in a significantly higher percentage of NB at 9.5 mo of healing. Based on histomorphometric analysis, AB results in the highest amount of NB formation in comparison to the other grafting materials. Bone substitute materials (allografts, alloplastic materials and xenografts) seem to be good alternatives to autogenous bone and can be considered as grafting materials to avoid disadvantages related to AB, including morbidity rate, limited availability and high volumetric change. Combining AB with alloplastic materials and xenografts brings no significant advantages regarding NB formation.

In vivo evaluation of shark teeth-derived bioapatites

OBJECTIVE

The present work proposes the shark teeth as a new source of bioapatites for bone filler applications in maxillary sinus elevation, periodontal regeneration or implants placement. This abundant fishing by-product provides an improved hydroxyapatite (HA) with fluorine contributions. The in vivo evaluation of osteointegration and bone mineral density levels promoted by these marine bioapatites was the main objective.

MATERIALS AND METHODS

Marine bioapatite granules of two sizes (1 mm, <20 μm) were obtained and characterized (XRD, SEM, ICP-OES) to determine morphology and composition. In vivo evaluation was performed, after bioapatites implantation in critical defects of parietal bone of 25 rats, for 3 weeks. Commercial synthetic HA/βTCP (60/40%) material and unfilled defects were used as controls. Radiology, micro-CT, histology and quantification of bone mineral density are presented.

RESULTS

These marine bioapatites presented a globular porous morphology. A biphasic composition ~70% apatitic (HA, apatite-CaF, fluorapatite) and ~30% non-apatitic phase (whitlockite, tricalcium bis(orthophosphate)), with contributions of F (1.0 ± 0.5%wt), Na (0.9 ± 0.2%wt) and Mg (0.65 ± 0.04%wt) was confirmed. After implantation period, higher osteointegration of 1-mm marine bioapatites than commercial synthetic granules was observed, together with bone formation from the defect surroundings but also at central area (potential osteoinductive properties). New bone cells penetrated inside pores and inter-granular cavities. Higher bone mineral density, in both 1-mm and <20-μm granules, than on commercial synthetic graft was determined, being significant in 1-mm bioapatites (a P < 0.05).

CONCLUSION

Shark teeth bioapatites were successfully validated as new functionally efficient bone filler in rat model, promoting significantly increased bone mineral density than synthetic control.

A histomorphometric assessment of collagen-stabilized anorganic bovine bone mineral in maxillary sinus augmentation - a prospective clinical trial

OBJECTIVE

To histomorphometrically compare the use of collagen-stabilized anorganic bovine bone (ABBM-C) (test) to anorganic bovine bone + autogenous bone (ABBM + AB) (control) in maxillary sinus augmentation.

MATERIALS AND METHODS

Forty (n = 40 sinuses) patients underwent sinus augmentation and received either control (20 sinuses) or test bone graft (20 sinuses). Bone samples were harvested from the augmented sinuses 5 months postgrafting. The samples were processed for histomorphometry, which assessed within the primary region of interest (ROI-1), the area fraction of new bone (%NB), graft particle osseointegration (% OI), residual graft (%RG), and soft tissue components (% STM). The same analysis was also carried out in a second region of interest (ROI-2) located in a zone 1 mm proximal to the previous maxillary sinus floor.

RESULTS

In both ROI-1 and ROI-2, the mean % NB, %RG, and %STM in the control group were similar to mean values in the test group. The % OI was significantly greater in the control group (42.0 +/- 26.8) when compared to the test group (19.6 +/- 27.3) in ROI-2 (P < 0.05). No statistically significant differences were seen when ROI-1 and ROI-2 were compared except for improved %OI in ROI-2 in the control group. The mean proportion of lamellar bone to woven bone in the control group (1.22 ± 1.48) was significantly greater than the test group (0.38 ± 0.29) (P < 0.05).

CONCLUSION

ABBM-C exhibited very similar histomorphometric parameters to the composite graft of ABBM + AB. The ABBM + AB group was more mature as indicated by the significantly greater proportion of lamellar bone when compared to the ABBM-C. Improved % OI was seen in the zone proximal to the resident bony floor in the ABBM + AB group. Based on histological assessment, ABBM-C is a suitable bone substitute for the purposes of maxillary sinus augmentation. Its clinical utility may be indicated in cases of sinus membrane perforation and insufficient autogenous bone in the local area.

A histomorphometric assessment of collagen-stabilized anorganic bovine bone mineral in maxillary sinus augmentation - a randomized controlled trial in sheep

OBJECTIVE

To histomorphometrically compare the use of collagen-stabilized anorganic bovine bone (ABBM-C) (test) to anorganic bovine bone + autogenous bone (ABBM + AB) (control) in maxillary sinus augmentation.

MATERIALS AND METHODS

Nine sheep underwent bilateral sinus augmentation. Each sinus was randomized to receive either control or test bone graft. Three animals were sacrificed at 8 weeks, and six animals were sacrificed at 16 weeks post-grafting. The 18 sinuses were processed for histomorphometry, which assessed the area fraction of new bone (%NB), residual graft (%RG) and soft tissue components (% STM), as well as graft particle osseointegration (% OI), within three zones equally distributed from the augmented sinus floor.

RESULTS

At week 16, a significant increase in %NB was evident across all three zones in the control group when compared to week 8. A significantly greater %NB was evident in the control group when compared to the test group in zones 2 (P < 0.001) and 3 (P < 0.001). There was a significant increase in %OI in week 16 when compared to week 8 across all three zones in the control group (P < 0.001). %OI in the control group was significantly greater across all three zones when compared to the test group at week 16 (P < 0.001). Zone was found to be a significant main effect (P < 0.001) that was independent of time and treatment with decreasing %OI in distant zones. %RG did not significantly change with time for both groups. There was a significant reduction in %ST in week 16 when compared to week 8 across all three zones in the control group (P < 0.001). %ST in the test group was significantly greater across all zones when compared to the control group at week 16 (P < 0.001).

CONCLUSION

Both groups exhibited very similar histomorphometric measurements in the zones proximal to the resident sinus wall. The % NB and % OI were greatest in the zones proximal to resident bony walls and gradually decreased as the distance from the proximal walls increased. There was greater % NB and % OI in the control group when compared to the test group in the distant zone.

Horizontal and vertical reconstruction of the severely resorbed maxillary jaw using subantral augmentation and a novel tenting technique with bone from the lateral buccal wall

AIM

The aim of this study was to evaluate the effect of using the lateral wall bone in sinus lifting two-dimensional reconstruction on bone augmentation.

PATIENTS AND METHODS

Ten patients affected by class V or VI maxillary atrophy with less than 3 mm of residual horizontal ridge were selected. Using a piezo-ultrasonic surgery tip bony lateral wall was cut. To expose native bone to the bone graft, multiple perforations, made through the cortical plate of the recipient site with a round bur. Once the bony buccal wall was adjusted it was fixed away from the ridge with two 1.5 x 13 mm bone fixation screws. Deficiencies created between the bony buccal wall and the ridge was filled with a mineralized cortical bone. A pericardium membrane was then placed on the graft. A biopsy for histologic evaluation was made.

RESULTS

The data analysis in bone volume changes reported significant differences between the anterior and posterior locations before and after grafting (p < 0.05). The biopsy shows mature cancellous bone with predominantly lamellar structure.

CONCLUSION

The use of the lateral wall bone in sinus lift surgery showed significant increase in bone volume.

Histomorphometric analysis of maxillary sinus augmentation using an alloplast bone substitute

PURPOSE

To evaluate the regenerative potential of a fully synthesized homogenous hydroxyapatite:β-tricalcium phosphate 60:40 alloplast material in sinus lift procedures.

MATERIALS AND METHODS

Hydroxyapatite:β-tricalcium phosphate was used for sinus floor augmentation. After 9 months, 12 biopsies were taken from 12 patients. Routine histologic processing was performed and specimens were analyzed using a light microscope and a digital camera.

RESULTS

Histologic evaluation showed 26.4% newly formed bone, 27.3% residual graft material, and 46.3% bone marrow. The osteoconductive index was 33.5%.

CONCLUSIONS

Hydroxyapatite:β-tricalcium phosphate 60:40 alloplast material was found to be biocompatible and osteoconductive in maxillary sinus augmentation procedures.

Evaluation of the osteoconductive potential of bone substitutes embedded with schneiderian membrane- or maxillary bone marrow-derived osteoprogenitor cells

AIM

Sinus augmentation procedures commonly employ osteoconductive scaffolding materials to stimulate and support bone formation. The aim of this study was to develop a simple screening methodology for the evaluation of the osteoconductive potential of various bone graft materials prior to clinical use.

MATERIALS AND METHODS

Materials tested were Bio-Oss, Bi-Ostetic, OraGraft, and ProOsteon. These Simple and composite bone substitutes were embedded with osteoprogenitor cells derived from either the human maxillary sinus schneiderian membrane (hMSSM) or from maxillary tuberosity bone marrow and then monitored both in vitro and in vivo.

RESULTS

Cell adherence and proliferation was most pronounced in OraGraft, followed by ProOsteon. In vivo bone formation, within the bone graft, was also observed, with most marked results in OraGraft and ProOsteon grafts.

CONCLUSIONS

The proposed osteoconductivity testing method proved simple, informative, and reliable for the purpose of screening candidate biomaterials for sinus lifting or sinus augmentation.

Histological results after maxillary sinus augmentation with Straumann® BoneCeramic, Bio-Oss®, Puros®, and autologous bone. A randomized controlled clinical trial

OBJECTIVE

This investigation focused on a comparison of clinical and histological characteristics after sinus floor augmentation with biphasic calcium phosphate (BCP, Straumann BoneCeramic(®) ), anorganic bovine bone (ABB, Geistlich Bio-Oss(®) ), mineralized cancellous bone allograft (MCBA, Zimmer Puros(®) ), or autologous bone (AB).

MATERIALS AND METHODS

Thirty consecutive patients with a posterior edentulous maxillary situation and a vertical bone height less than or equal to 4 mm were included in this study. A two-stage procedure was carried out. After augmentation of the maxillary sinus with ABB, BCP, MCBA, or AB followed by a healing period of 5 months, biopsies were taken with simultaneous implant placement. The samples were analyzed using microradiography and histology.

RESULTS

Ninety-four implants were placed in the augmented positions and 53 bone biopsies were taken and evaluated. The bone volume fraction of newly formed bone was measured as 30.28 ± 2.16% for BCP, 24.9 ± 5.67% for ABB, 41.74 ± 2.1% for AB, and 35.41 ± 2.78% for MCBA with significant increases in bone volume of AB vs. BCP and ABB, and MCBA vs. ABB samples. Significantly different residual bone substitute material was measured as 15.8 ± 2.1% in the BCP group and 21.36 ± 4.83% in the ABB group.

CONCLUSION

As it provides the highest rate of de novo bone formation, AB can be considered to remain the gold standard in sinus floor augmentation. All tested control materials showed comparable results and are suitable for maxillary sinus augmentation.

The effect of bovine bone graft with or without platelet-rich plasma on maxillary sinus floor augmentation

PURPOSE

The purpose of this study was to compare Unilab Surgibone (USB) (Mississauga, Ontario, Canada), a bone xenograft (bovine), with platelet-rich plasma (PRP) and USB without PRP to augment the human maxillary sinus in preparation to receive dental implants.

PATIENTS AND METHODS

Patients who had bilateral pneumatized maxillary sinuses were included. Sinuses on one side were augmented with the USB-PRP combination and formed the study group, whereas the opposite-side sinuses were augmented with USB alone and served as controls. Bone biopsy specimens were taken during implant placement at 6.8 ± 0.9 months after maxillary sinus floor augmentation. Resonance frequency analysis measurements were performed at implant placement (first control) and before the prosthetic stage (second control), at 6.5 ± 0.7 months after implant surgery.

RESULTS

There were 10 patients (7 men and 3 women; mean age, 53.7 ± 0.8 years). Integration between new bone and residual grafts was histologically observed in all samples. The volumes of soft tissue were 59.9% ± 7.5% and 57.8% ± 4.4% in the control and study groups, respectively; residual graft, 21.9% ± 6.6% and 23.6% ± 5.9%, respectively; new bone, 15.8% ± 4.8% and 16.0% ± 3.8%, respectively; and trabecular bone, 64.7% ± 22.5% and 69.1% ± 18.6%, respectively. A positive correlation was found between new bone volume and trabecular bone volume (P = .0001). The mean Implant Stability Quotient (ISQ) values were 71.7 ± 4.9 and 70.3 ± 5.7 in the control and study groups, respectively, at first control and 75.4 ± 6.4 and 74.4 ± 6.4, respectively, at second control. The mean ISQ values at second control in both groups were significantly higher than at first control (P = .043 and P = .028, respectively). No statistically significant differences were observed between groups (P > .05).

CONCLUSION

The combination of USB and PRP does not have any effect on new bone formation and implant stabilization.

Maxillary sinus floor elevation and grafting with deproteinized bovine bone mineral: a clinical and histomorphometric study

OBJECTIVES

This study evaluated the histomorphometric and clinical outcomes of maxillary sinus floor elevation using deproteinized bovine bone mineral (DBBM).

MATERIAL AND METHODS

Maxillary sinuses with a residual vertical height of <5 mm were augmented with DBBM alone before implant placement 9 months later. At the time of implant surgery, trephine samples were removed and histological and histomorphometric analyses were performed to examine the percentage of bone and residual graft using point counting and software-aided analysis. Patients were recalled for clinical and radiographic examination up to 3 years later.

RESULTS

Twenty-five patient specimens were analysed. The percentages of regenerated bone and residual graft material were 19% and 40%, respectively. Software-aided analysis was comparable to point counting. Twelve patients attended for clinical follow-up. Implants placed into this regenerated bone exhibited success and survival rates of 100% after an average follow-up of 3 years. The average vertical height gained was 7.9 mm.

CONCLUSIONS

The use of DBBM alone in maxillary sinus floor elevation is a predictable method to gain vertical bone height in the posterior maxilla.

Applicability of equine hydroxyapatite collagen (eHAC) bone blocks for lateral augmentation of the alveolar crest. A histological and histomorphometric analysis in rats

This study assessed the mechanical characteristics, biocompatibility and osteoconductive properties of an equine hydroxyapatite collagen (eHAC) bone block when applied as a bone substitute for lateral augmentation of rat mandible. 96 rats underwent lateral augmentation of the mandible, using two substitute bone blocks (eHAC or Bio-Oss spongiosa) or autologous bone grafts. Signs of inflammation, amount of bone formation and ingrowth of bone into the bone blocks were assessed at 1 and 3 months. eHAC blocks were mechanically rigid and could be fixed firmly and easily. Bio-Oss spongiosa blocks were brittle and fixation was difficult. eHAC and Bio-Oss spongiosa blocks were biocompatible and induced few or no signs of inflammation. Inflammation prevalence between the groups was not statistically different. Bone formation and bone growth into the blocks was significantly higher in eHAC than Bio-Oss spongiosa blocks, but lower than in autologous bone grafts (after 1 and 3 months). Regression analysis showed that the autologous bone graft predicted new bone formation at both time points. The eHAC block was only a predictor at 1 month; a trend was found at 3 months. The application of biodegradable membranes was not related to more bone ingrowth.

A meta-analysis of histomorphometric results and graft healing time of various biomaterials compared to autologous bone used as sinus floor augmentation material in humans

BACKGROUND

To date, no studies have been published in which histomorphometric data from a large group of patients comparing various biomaterials for sinus floor augmentation procedures were evaluated.

MATERIALS AND METHODS

A meta-analysis of the English literature from January 1993 till April 2009 was carried out. Out of 147 titles, according to our criteria, 64 articles were selected for analysis describing the use of autologous bone and their alternatives, such as allogenic, xenogenic, and alloplastic materials.

RESULTS

On the basis of autologous bone grafting, a reference value for total bone volume (TBV) of 63% was found. Particulation of the bone graft resulted in a general reduction of −18% in TBV. Delayed implant placement reduced the TBV with −7%. Overall TBV was 8% or 6% higher if a biopsy was, respectively, taken before 4.5 months or after 9.0 months after initial sinus augmentation surgery. Allogenic, xenogenic, alloplastic, or combinations of graft materials all resulted in a significant lower amount of TBV compared to autologous bone grafting ranging from −7% to −26%. Inventorying the effect of "biopsy time" for autologous bone, the TBV was significantly higher before 4.5 and after 9.0 months of healing time compared to period in between. Surprisingly, no significant differences in TBV with respect to "biopsy time" for bone substitutes were found.

CONCLUSIONS

On the basis of the aspect of TBV autologous bone still has to be considered to be the gold standard in sinus augmentation surgery. However, the consequence of the TBV for implant survival is still unraveled yet.

Histomorphometric analysis after maxillary sinus floor augmentation using cancellous bone-block allograft

BACKGROUND

Cancellous bone-block allografts may contribute to improved initial implant stability during sinus augmentation in cases with posterior atrophic maxillary ridge height < or =4 mm. The present study histologically and histomorphometrically evaluates the application of cancellous bone-block allografts for maxillary sinus-floor augmentation.

METHODS

Thirty-one consecutive patients, 16 females and 15 males (age range, 25 to 65 years; mean age: 54 +/- 9 years) underwent sinus augmentation with simultaneous implant placement with cancellous bone-block allografts. After 9 months, a second-stage surgery was performed. The previous window location was determined. A cylindrical sample core was collected. All specimens were prepared for histologic and histomorphometric examinations.

RESULTS

Seventy-two of 76 implants were clinically osseointegrated (94.7%). All patients received a fixed implant-supported prosthesis. The mean t values of newly formed bone, residual cancellous bone-block allograft, marrow and connective tissue were 26.1% +/- 15% (range: 10% to 58%); 24.7% +/- 19.4% (range: 0.6% to 71%), and 49.2% +/- 20.4% (range: 14.9% to 78.9%), respectively. No statistically significant histomorphometric differences regarding newly formed bone were found between genders (27.02% in males versus 25.68% in females; P = 0.446), ages (29.82% in subjects < or =40 years old versus 24.43% in subjects >40 years old; P = 0.293), presence of membrane perforations (25.5% in non-perforated sinuses versus 27.3% in perforated sinuses; P = 0.427), and residual alveolar bone height (25.85% for residual alveolar bone height <2 mm versus 26.48% for residual alveolar bone height of 2 to 4 mm; P = 0.473).

CONCLUSION

The cancellous bone-block allograft is biocompatible and osteoconductive and permits new bone formation in sinus augmentations with simultaneous implant-placement procedures in extremely atrophic posterior maxillae.

Maxillary sinus augmentation by the crestal core elevation technique

BACKGROUND

The crestal core elevation (CCE) technique is reportedly a less invasive procedure than the lateral window elevation technique. We retrospectively evaluated long-term outcomes of CCE procedures over an 11-year time period.

METHODS

Core preparations were made after extractions of 57 upper molars in 45 patients. Extraction sites were drilled with a calibrated trephine bur to an estimated distance of 1 mm from the sinus membrane. The trephined interradicular bone and underlying sinus membrane were imploded into the sinus. The surgical crater and residual extraction socket were filled with deproteinized bovine bone mineral or freeze-dried bone allograft, stabilized, and protected with an absorbable collagen membrane and fully covered with coronally positioned flaps. Implants were placed 4 months later. Success was defined if ≥9 mm available bone height was available. Where the available bone height varied between 7 and 9 mm, implant placement was complemented using the bone-added osteotome sinus floor elevation technique; those sites were defined as a "partial success."

RESULTS

The CCE technique was successful in 31 (68.9%) out of 45 sites, and partially successful in six (13.3%) out of 45 sites. Eight sites failed (17.8%). Surgical failures were caused by core detachment resulting in large tears of the sinus membrane. Implants placed in successful sites presented a 100% survival rate during the study duration.

CONCLUSIONS

CCE implemented simultaneously with molar extractions provided therapeutic benefits and clinical limitations. The subsequent implant placement using CCE revealed an excellent survival rate in the study population evaluated.

Biomechanical and microscopic response of bone to titanium implants in the presence of inorganic grafts

This study evaluated the biomechanical and microscopic response of previously grafted bone to titanium implants. The lower incisors of 16 rabbits were surgically extracted, and bilateral perforations communicating with the remaining sockets were created distally. A socket/perforation defect on each mandible was chosen at random to be immediately filled with a xenogenic graft, whereas the contralateral perforation was left to heal naturally and served as a paired control. After 60 days, titanium implants were installed in the previously operated areas. After periods of 2 and 6 months, the animals were killed, and the force necessary to retrieve implants as well as the bone-implant contact (BIC) and bone mass (BM) were quantified and statistically compared by 2-way analysis of variance and Tukey's test (α  =  .05). No significant differences in removal torque were observed, either by time or by treatment condition. Differences in BIC and BM between experimental and control groups were not statistically significant through the intervals studied (P < .05). The presence of a xenogenic graft did not influence the microscopic tissue response to titanium implants or fixation into newly formed or mature bone.

The "dome phenomenon" associated with maxillary sinus augmentation

AIM

This case series is aimed to report a new phenomenon, the "dome phenomenon," which was observed in infected augmented sinuses over several years.

METHODS

Five patients are presented in whom sinus lift augmentation resulted in postoperative infection with inflammation and suppuration. The patients received aggressive anti-inflammatory treatment and surgical debridement of the inflamed tissue, including some grafted material performed through the lateral window of the primary procedure.

RESULTS

The inflammatory condition was reversed, and the site healed clinically. Radiographically, a dome-shaped, radio-opaque tissue was observed at the superior most aspect of the grafted sinus. This "dome phenomenon" was further confirmed during dental implant placement, which indicates healing potential adjacent to the maxillary sinus membrane.

CONCLUSIONS

The current report, as well as other studies and case series, suggests that there is great potential for healing and bone formation in the maxillary sinus membrane. The precise mechanism is not known. Further clinical and histologic studies are needed to understand the regenerative potential of the Schneiderian membrane.

A new biphasic osteoinductive calcium composite material with a negative Zeta potential for bone augmentation

The aim of the present study was to analyze the osteogenic potential of a biphasic calcium composite material (BCC) with a negative surface charge for maxillary sinus floor augmentation. In a 61 year old patient, the BCC material was used in a bilateral sinus floor augmentation procedure. Six months postoperative, a bone sample was taken from the augmented regions before two titanium implants were inserted at each side. We analyzed bone neoformation by histology, bone density by computed tomography, and measured the activity of voltage-activated calcium currents of osteoblasts and surface charge effects. Control orthopantomograms were carried out five months after implant insertion. The BCC was biocompatible and replaced by new mineralized bone after being resorbed completely. The material demonstrated a negative surface charge (negative Zeta potential) which was found to be favorable for bone regeneration and osseointegration of dental implants.

A histomorphometric meta-analysis of sinus elevation with various grafting materials

Several grafting materials have been used in sinus augmentation procedures including autogenous bone, demineralized freeze-dried bone (DFDBA), hydroxyapatite, beta-tricalcium phosphate (beta-TCP), anorganic deproteinized bovine bone and combination of these and others. Up to now a subject of controversy in maxillofacial surgery and dentistry is, what is the most appropriate graft material for sinus floor augmentation.

PURPOSE

The aim of this study is to provide a body of evidence-based data regarding grafting materials in external sinus floor elevation concerning the fate of the augmented material at the histomorphological level, through a meta-analysis of the available literature.

MATERIALS AND METHODS

The literature searches were performed using the National Library of Medicine. The search covered all English and German literature from 1995 until 2006. For analyzing the amount of bone the parameter "Total Bone Volume" (TBV) was assessed. TBV is determined as the percentage of the section consisting of bone tissue.

RESULTS

In a relatively early phase after implantation the autogenous bone shows the highest TBV values. Interestingly, the different TBV levels approximate during the time. After 9 months no statistically significant differences can be detected between the various grafting materials.

CONCLUSION

From a clinical point of view, the use of autogenous bone is advantageous if a prosthetic rehabilitation (with functional loading) is expected within 9 months. In other cases the use of anorganic deproteinized bovine bone in combination with autogenous bone seems to be preferable. Donor side morbidity is ignored in this conclusion.

Ridge augmentation and maxillary sinus grafting with a biphasic calcium phosphate: histologic and histomorphometric observations

OBJECTIVES

This retrospective study reports on histologic and histomorphometric observations performed on human biopsies harvested from sites augmented exclusively by biphasic calcium phosphate [BCP: hydroxyapatite (HA)/ tricalcium phosphate (TCP) 60/40] and healed for a minimum of 6 months.

MATERIALS AND METHODS

Five patients benefited from three augmentation regimens (i.e.: one-stage lateral augmentation; two-stage lateral augmentation; and two-stage sinus grafting). In all patients, a degradable collagen membrane served as a cell-occlusive barrier. Core biopsies were obtained from lateral as from crestal aspects 6-10 months after augmentation surgeries. For histologic and histomorphometric evaluations, the non-decalcified tissue processing was performed.

RESULTS

The histological examination of 11 biopsies showed graft particles frequently being bridged by the new bone, and a close contact between the graft particles and newly formed bone was seen in all samples. The mean percentages of newly formed bone, soft tissue compartment, and graft material were 38.8% (+/-5.89%), 41.75% (+/-6.08%), and 19.63% (+/-4.85%), respectively. Regarding bone-to-graft contact values, the percentage of bone coverage of graft particles for all biopsies ranged from 27.83% to 80.17%. The mean percentage of bone coverage was 55.39% (+/-13.03%).

CONCLUSIONS

Data from the present study demonstrated osteoconductivity scores for the BCP material (HA/TCP 60/40) in patients resembling those previously shown for grafting materials of xenogenic and alloplastic origin.

The Schneiderian membrane contains osteoprogenitor cells: in vivo and in vitro study

Recent studies successfully demonstrated induction of new bone formation in the maxillary sinus by mucosal membrane lifting without the use of any graft material. The aim of this work was to test the osteogenic potential of human maxillary sinus Schneiderian membrane (hMSSM) using both in vitro and in vivo assays. Samples of hMSSM were used for establishment of cell cultures and for histological studies. Flow cytometry analysis was performed on P(0), P(1), and P(2) cultures using established mesenchymal progenitor cell markers (CD 105, CD 146, CD 71, CD 73, CD 166), and the ability of hMSSM cells to undergo osteogenic differentiation in culture was analyzed using relevant in vitro assays. Results showed that hMSSM cells could be induced to express alkaline phosphatase, bone morphogenic protein-2, osteopontin, osteonectin, and osteocalcin and to mineralize their extracellular matrix. Inherent osteogenic potential of hMSSM-derived cells was further proven by in vivo experiments, which demonstrated the formation of histology-proven bone at ectopic sites following transplantation of hMSSM-derived cells in conjunction with an osteoconductive scaffold. This study provides the biological background for understanding the observed clinical phenomena in sinus lifting. Our results show that a genuine osteogenic potential is associated with the hMSSM and can contribute to development of successful sinus augmentation techniques.

Performance of threaded versus sintered porous-surfaced dental implants using open window or indirect osteotome-mediated sinus elevation: a retrospective report

BACKGROUND

The purpose of this retrospective report was to evaluate the performance of dental implants placed in a teaching environment in patients requiring maxillary sinus elevation.

METHODS

Threaded (acid-washed or sand-blasted acid-etched) and sintered porous-surfaced (SPS) press-fit implants were used. Sinuses were managed using direct (open window) or indirect (osteotome-mediated) techniques. Records were available for 97 implants in 62 patients. Preoperative subantral bone heights were determined from radiographs, primarily panoramic. Of 69 threaded implants used, 40 and 29 were placed using direct (DTH) and indirect (ITH) techniques, respectively. Twenty-eight SPS implants were placed using the indirect technique. Implant failure rates using the Kaplan-Meier method of analysis and cumulative crestal bone loss (the latter based on bone levels seen in the most recent radiographs) were determined for both types of implants.

RESULTS

The mean preoperative subantral bone height for DTH implants was 5.0 mm (range, 1 to 12 mm). Preoperative bone heights for ITH implants and SPS implants placed using the indirect approach were 7.2 mm (range, 4 to 12 mm) and 4.2 mm (range, 3 to 6 mm), respectively. Significant differences in preoperative bone height were seen between DTH and ITH implants (P <0.0001) and between ITH and SPS implants (P <0.0001). Average functional times were 18.7 months and 16.3 months for DTH and ITH implants, respectively, whereas the average functional time for SPS implants was 49.9 months. Time in function was significantly greater (P <0.0001) for SPS than DTH and ITH implants. Significant differences in implant length were also seen, with SPS implants significantly shorter than DTH or ITH implants. Three implants failed to integrate, one in each of the three treatment groups, giving initial survival rates of 97.5%, 96.6%, and 96.4% for DTH, ITH, and SPS implants, respectively. Mean cumulative crestal bone loss measurements were 1.84, 1.90, and 0.57 mm for DTH, ITH, and SPS implants, respectively. Bone loss was significantly less with SPS implants than with DTH or ITH implants. A second SPS implant failed after 7 years in function, likely because of prosthetic deficiencies. This late failure reduced the Kaplan-Meier survival rate to 80.4% for the SPS group.

CONCLUSION

Results from this teaching clinic suggest that the use of dental implants with sinus elevation procedures is a predictable treatment for the resorbed posterior maxilla.

Histomorphometric assessment of bone formation in sinus augmentation utilizing a combination of autogenous and hydroxyapatite/biphasic tricalcium phosphate graft materials: at 6 and 9 months in humans

OBJECTIVE

The aim of this study was to examine the efficacy of a new biphasic hydroxyapatite/tricalcium phosphate (HA/TCP) bone substitute in combination with particulate autogenous bone in sinus floor augmentation procedures.

MATERIAL AND METHODS

A simultaneous or a two-stage sinus augmentation and implant placement were conducted in 28 patients. A mixture of HA/TCP and autogenous bone chips in a 1 : 1 ratio was used as the grafting biomaterial. Cylindrical specimen bone retrieval was performed in all patients except one. Specimens were harvested either at 6 (n=14) or 9 (n=13) months post-augmentation. For histologic and histomorphometric evaluations, the non-decalcified tissue processing (Donath's technique) was performed.

RESULTS

Newly formed bone around the grafted particles was found in all samples. The encircling, highly cellular bone followed the outline of the grafted particles in direct contact. Both woven and lamellar types of bone were observed. Morphometrically, the total mean bone area fraction of all sections was 34.8+/-10.3%, increasing from 28.6+/-7.8% at 6 months to 41.6+/-8.3% at 9 months (P<0.001). Mean particle area fraction average was 25.5+/-11.6% and 23.5+/-9.3% at 6 and 9 months, respectively, with a total mean of 24.5+/-10.4%. The increase in bone area fraction was not significantly correlated to the decrease of the grafted particles area fraction.

CONCLUSIONS

The biphasic HA/TCP showed biocompatible and osteoconductive properties. This alloplast as a composite with autogenous bone chips promotes newly formed bone, which increases in its fraction along an extended healing period.

Vertical bone augmentation with granulated brushite cement set in glycolic acid

Brushite cements are a biocompatible materials that are resorbed in vivo. A new cement composed of a mixture of monocalcium phosphate (MCP) and beta-tricalcium phosphate (beta-TCP) that sets using glycolic acid (GA) was synthesized and characterized. After setting, the cement composition, derived from X-ray diffraction, was 83 wt % brushite and 17 wt % beta-TCP with an average brushite crystal size of about 2.6 +/- 1.4 microm. The cement has a diametral tensile strength of 2.9 +/- 0.7 MPa. Granules prepared from the set-cement were used as grafting material in bone defects on rabbit calvaria for evaluating in vivo its bone regeneration capacity. Considerable cement resorption, improvement in the bone mineral density, and bone neoformation was observed after 4 weeks of the granules' implantation.

Macroscopical, histological, and morphometric studies of porous bone-replacement materials in minipigs 8 months after implantation

OBJECTIVE

The aim of this investigation was to test the induction of bone formation and biodegradation of different biomaterials based on calcium phosphate (CaP). Up to now, hydroxyapatite and beta-tricalcium phosphate ceramics have routinely been sintered at temperatures of 1300 degrees C. The new CaP biomaterials tested are fabricated by a sol-gel process at only 700 degrees C.

STUDY DESIGN

Critical-size defects (>5 cm(3)) in the mandible of 15 adult Goettingen minipigs were filled with 1 of the 2 new types of CaP biomaterials, or with 1 of 2 well-known old-type ceramics, or with a gelatin sponge (in the control group). Macroscopical, histological, and morphometric examination of the former defect areas were made 8 months postoperatively.

RESULTS

Eight months after implantation of the new CaP biomaterials, complete bone formation was observed in the defect area, and at the same time, the foreign material was resorbed almost completely. After implantation of the classical types of ceramics, only incomplete bone formation and a lesser resorption rate of the foreign bodies were noted. The difference in the bone formation rate was significant: more than 93% for the new CaP biomaterials versus less than 58% for the classical types of ceramics (P < 0.01).

CONCLUSION

The biological behavior of the new CaP biomaterials was better than that of the old-type sintered ceramic bone-grafting materials. These new CaP matrices are suitable for filling bone defects and are of interest for dentists, including implantologists, craniomaxillofacial and orthopedic surgeons, as well as traumatologists.

Experimental Intrabony and Periodontal Defects Treated With Natural Mineral Combined With a Synthetic Cell-Binding Peptide in the Canine: Morphometric Evaluations

BACKGROUND

A synthetic peptide (P-15) analog of collagen added to anorganic bovine bone mineral (ABM) has recently been used as an enhanced bone graft material (ABM/P-15). The objective of this study was to test the contribution of ABM/P-15 in a new putty form (PEP) in two experimental membrane-protected defects: periodontal and intrabony. Its efficacy as filler biomaterial in guided tissue regeneration (GTR) and guided bone regeneration (GBR) procedures was evaluated histologically and morphometrically.

METHODS

In the maxillary canines, a facial mucoperiosteal flap was raised bilaterally in nine dogs. Two circular defects, 5 mm in diameter and 2 mm in depth, were made on each side: a fenestrated periodontal on the canine root and an intrabony in the alveolar diastema, anteriorly. PEP particles filled both defects on one side; the contralateral side was blood filled (control). All surgical sites were covered with a bioabsorbable membrane. Histologically, at 4 months, tissue blocks were made using the cutting/grinding non-decalcification method followed by morphometric analysis. In the periodontal fenestration root surface, the linear percentage of new cementum (%CEM), area percentage of new bone (%NB), and residual biomaterial particles (%PEP) were calculated. These same measurements were calculated at the intrabony sites, except cementum. The amount of direct NB to PEP contact was measured to assess the osteoconductivity level (OSC). The Pearson correlation test was used to evaluate any significant relationship between the different measured parameters.

RESULTS

In the grafted and non-grafted fenestration root surface defects, %CEM averaged 59.5% and 73.9% (P <0.02), respectively; %NB averaged 36.1% and 31.4%, respectively; and %PEP averaged 20.6%. The mean percentage of OSC was 52.4%. In the intrabony grafted and non-grafted sites, %NB averaged 50.7% and 60.1%, respectively (P <0.02). Residual %PEP averaged 26.1%, and OSC averaged 35.6%. At the intrabony sites, higher %NB and lower %OSC were found compared to the fenestration sites (P <0.001 and P <0.03, respectively). Correlation analysis showed a negative correlation between %NB and %PEP at the fenestration defects. In between the two defect types, %OSC was significantly correlated (P <0.05).

CONCLUSIONS

ABM/P-15 putty showed osteoconductive and biocompatible qualities. However, at 4 months in this model, no enhanced regeneration was present compared to a higher CEM and NB growth detected at non-grafted membrane-protected sites.

Maxillary sinus augmentation

Attention to the principles of bone grafting, bone healing, and maxillary sinus physiology as well as anatomy is critical to the successful placement of dental implants in the posterior maxilla. The integration of these principles must take into account the restorative dental requirements and the patient's autonomy in guiding implant reconstruction. As in so many clinical disciplines, additional research is needed to provide better guidance for clinicians. Despite some gaps in our knowledge, however, sinus augmentation procedures have proven to be safe and effective and have permitted the placement of implants in sites that would have otherwise been impossible to treat. This article summarizes techniques and technologies related to maxillary sinus augmentation.

Platelet-Rich Plasma Combined With a Porous Hydroxyapatite Graft for the Treatment of Intrabony Periodontal Defects in Humans: A Comparative Controlled Clinical Study

BACKGROUND

The aim of the present controlled clinical study was to compare platelet-rich plasma (PRP) combined with a biodegradable ceramic, porous hydroxyapatite (HA) with a mixture of HA and saline in the treatment of human intrabony defects.

METHODS

Seventy interproximal intrabony osseous defects in 70 healthy, non-smoking subjects diagnosed with chronic periodontitis were included in this study. Thirty-five subjects each were randomly assigned to either the test group (PRP and HA) or control group (HA with saline). Clinical and radiographic measurements were determined at baseline and the 12-month evaluation.

RESULTS

When compared to baseline, the 12-month results indicated that, while both treatment modalities resulted in significant changes in all clinical parameters (gingival index, bleeding on probing, probing depth, clinical attachment level, and intrabony defect fill; P <0.001), the test group exhibited statistically significant changes compared to the control sites in probing depth reduction: 4.7 +/- 1.6 mm versus 3.7 +/- 2.0 mm (P <0.05); clinical attachment gain: 3.4 +/- 1.7 mm versus 2.0 +/- 1.2 mm (P <0.001); and vertical relative attachment gain: 70.3% +/- 23.4% versus 45.5% +/- 29.4% (P <0.001).

CONCLUSION

Treatment with a combination of PRP and HA compared to HA with saline led to a significantly more favorable clinical improvement in intrabony periodontal defects.

The sinus lift with phycogenic bone substitute. A histomorphometric study

OBJECTIVES

The aim of this histomorphometric prospective study was to ascertain the efficacy of phycogenic bone substitute in an augmented sinus. The process of graft healing, bone remodeling, and biomaterial replacement was examined.

MATERIAL AND METHODS

The phycogenic material (fluorohydroxyapatite) made from calcium-encrusted sea algae was used for the sinus lifts. Twenty-four procedures were carried out (one-stage and two-stage equally) and 45 titanium stepped-screw implants were placed. The patients were followed for 12-23 months. In intervals of 6, 9, 12, or 15 months after the sinus lift, 24 graft specimens were taken with a trephine bur. These specimens were examined histomorphometrically.

RESULTS

The grafting material was gradually resorbed and replaced by newly formed bone. Between the sixth and 15th month after the sinus lift, the percentage of newly formed bone grew linearly (from 15.5+/-9.6% to 40.8+/-15.3%) and the percentage of bone substitute decreased linearly (from 34.5+/-8.6% to 13+/-9.6%). After 15 months, the density of trabeculae in grafted bone corresponded to cancellous bone of good quality; however, the bone substitute was not completely resorbed during this period. No significant difference between the quality of the newly formed bone in the cases of the one- and two-stage sinus lifts was found.

CONCLUSION

Sinus lift carried out with phycogenic bone substitute was shown to be an effective method with limited invasiveness and a high survival rate of implants (97.8%).

Repair of bone defects by applying biomatrices with and without autologous osteoblasts

QUESTION

Is it possible to stimulate osteoconduction and osteogenesis to improve bone formation in critical-size defects in order to avoid bone grafting?

MATERIAL AND METHODS

Full thickness, critical-sized defects were created in the anterior mandible of 16 adult mini-pigs. The defects were filled with a new bioactive matrix (60% hydroxyapatite and 40% beta-tricalciumphosphate), produced by an innovative low temperature sol-gel-process (120 degrees C). The biomatrix was tested alone and in combination with cultured autologous osteoblasts. In a control group, periosteum was the only bone producing source. Five weeks postoperatively, the animals were sacrificed and the defects analysed macroscopically, histologically and radiographically.

RESULTS

The highest rate of new bone formation was in the biomatrix group without osteoblasts (73% of the former defect). The biomatrix was degraded at the same speed as new bone was laid down. In the control group, bone formation of only 59% was observed. Additional transplantation of autologous osteoblasts in combination with the biomatrix did not result in more bone production than in the control group(!).

CONCLUSION

This new bioactive calciumphosphate matrix seems to be a promising bone replacement material.