Histomorphometric Analysis of Newly Formed Bone After Maxillary Sinus Floor Augmentation Using Ground Cortical Bone Allograft and Internal Collagen Membrane

Patient and implant-related risk factors for implant failure of one-stage lateral sinus floor elevation: A 2- to 10-year retrospective study

OBJECTIVES

This retrospective study aimed to evaluate the early and late implant failure rates of one-stage lateral sinus floor elevation (LSFE) and to identify the patient and implant-related risk factors associated with these failures.

MATERIALS AND METHODS

All patients treated with one-stage LSFE from January 2014 to December 2021 were evaluated for inclusion. A total of 618 patients with 936 implants met the inclusion criteria. Clinical and radiographic information about patient and implants was collected. Univariate and multivariate Cox proportional hazards frailty regression models were performed to identify risk factors for early and late implant failure.

RESULTS

The cumulative implant survival rate was 95.62% (95% CI 93.90%-97.68%), with 16 early implant failures and 25 late implant failures. The Cox analysis indicated that ≤3 mm residual bone height (RBH) was associated with a higher early failure rate. For late implant failure, smoking habit, ≤3 mm RBH, and certain implant brand were independent risk factors. Narrow sinus ostium, long infundibulum, and flat thickening of Schneiderian membrane might be non-independent risk factors for late implant failure. No significance was found in other variables, including age, periodontitis history, implant characteristics (position, diameter, length, protrusion length, marginal bone loss), surgeon experience, healing time, opposing dentition, and prosthesis.

CONCLUSIONS

One-stage LSFE is a predictable treatment for patients with atrophic maxilla. ≤3 mm RBH increased the risk of early implant failure, while smoking habit, ≤3 mm RBH, and certain implant brand were independent risk factors for late implant failure.

Using Platelet-Rich Fibrin in Combination With Allograft Bone Particles Can Induce Bone Formation in Maxillary Sinus Augmentation

BACKGROUND

Sinus pneumatization secondary to posterior maxillary tooth extraction can hinder proper implant installation. Maxillary sinus floor augmentation is a surgical procedure that has been proposed to overcome this issue.

PURPOSE

The aim of this study was to evaluate and compare the histomorphometric outcomes of sinus floor elevation using allograft bone particles with or without platelet-rich fibrin (PRF).

STUDY DESIGN, SETTING, SAMPLE

This randomized clinical trial included patients scheduled for maxillary sinus floor elevation in the Implant Department of Mashhad Dental School. Healthy adults with an edentulous maxilla and residual alveolar bone height of 3 mm or less were eligible to participate and were randomly allocated to intervention (A) or control (B) groups. Bone biopsies were obtained 6 months postoperatively.

PREDICTOR VARIABLE

The predictor variable was using a PRF membrane for maxillary sinus augmentation. In group A, sinus floor elevation was performed using PRF combined with bone allografts, while in group B only allograft particles were used.

MAIN OUTCOME VARIABLES

The primary outcome variables were the recorded postoperative histologic parameters, as in the area of newly formed bone, new bone marrow, and residual graft particles (μm2). The secondary outcome variables were the radiographically measured postoperative bone height and width at the graft site.

COVARIATES

Age and sex.

ANALYSES

Independent sample t-test was employed to compare the postoperative histomorphometric parameters between groups A and B. P value ≤ .05 was considered statistically significant.

RESULTS

A total of 20 patients (10 per group) completed the study. The mean rate of new bone formation was 43.25 ± 5.22% in group A and 38.25 ± 7.01% in group B. This difference was statistically insignificant (P = .087). The mean amount of newly formed bone marrow was significantly more in group A compared to group B (6.81 ± 2.19% vs 10.23 ± 4.49%; P = .044). The average amount of remaining particles was also significantly less in group A patients (9.35 ± 3.43% vs 13.18 ± 3.67%; P = .027).

CONCLUSION AND RELEVANCE

Incorporating PRF as an adjunctive grafting material results in fewer residual particles of allograft and in more bone marrow formation and may serve as a treatment option for developing the atrophic posterior maxilla.

Evaluation of the effect of autologous conditioned serum on the radiographic characteristics of hard tissue after horizontal bone augmentation in implant dentistry

Background. Bone deficiency in different areas is problematic in implant placement. Changes in histological, histomorphometric, and radiographic properties of hard tissues in the implant placement area affect many parameters of implant success. Autologous conditioned serum (ACS) is a blood product with high levels of IL1- receptor antagonists. Augmentation surgeries are required in many cases because implant placement in the edentulous areas requires a sufficient amount of bone. Therefore, this study radiographically evaluated the effect of autologous conditioned serum after horizontal bone augmentation. Methods. In this prospective RCT, 21 patients eligible patients were evaluated. The patient underwent horizontal ridge augmentation surgery in the area. The ACS-impregnated graft was in direct con-tact with the bone. The control side underwent the same surgical protocol without using ACS. Four months after surgery, a CBCT radiograph was taken, and radiographic changes in the two areas were calculated using the differences in the amount of bone formed in the horizontal dimension as well as the Hounsfield unit (HU). The data were reported using descriptive statistical methods, including means (standard deviations) and frequencies (percentages). According to the results of the Kolmog-orov-Smirnov test, the data had a normal distribution (P>0.05); therefore, paired t-test was used to compare the means of the parameters between the two groups. Results. IRadiographic examinations showed that the horizontal dimension of bone before surgery was similar between the two groups. However, after surgery in the ACS group (33.13±6.1), it was significantly higher than in the control group (62.1±86.4) (P>0.05). Also, the rate of horizontal dimension increase (the difference before and after surgery) in the ACS group was significantly higher than in the control group. Bone density before surgery was similar between the two groups. However, after surgery, there was a significant increase in the ACS group (75.56±330.42 HUs) compared to the control group (38.35±292.38 HUs) (P>0.05). Also, the rate of density increase (the difference before and after surgery) in the ACS group was significantly higher than in the control group. Conclusion. Radiographic evaluations of hard tissues showed a significant increase in the horizontal dimension of bone and density of newly formed bone using ACS compared to the control group.

Intraoperative complications and early implant failure after transcrestal sinus floor elevation with residual bone height ≤5 mm: A retrospective multicenter study

OBJECTIVE

Clinical indications for maxillary sinus floor elevation with transcrestal techniques have increased in recent years even in sites with minimal residual bone height (RBH). Nevertheless, limited information is currently available on incidence of intraoperative complications and early implant failure in these cases.

MATERIAL AND METHODS

This retrospective multicenter study was performed on anonymized clinical and radiographic records of patients who underwent transcrestal sinus floor elevation in seven clinical centers. Influence of different factors related to patient, and sinus anatomy and surgical technique on the incidence of intraoperative complications and early implant failure rate after transcrestal sinus lift were investigated.

RESULTS

A total of 430 patients treated with transcrestal sinus floor elevation for single-implant insertion in sites with RBH ≤5 mm were included in the final analysis. After 1 year of loading, 418 implants of 430 were satisfactorily in function. Early implant failure was recorded in 12 cases (2.8%); results were significantly associated with the presence of large sinus cavities and with the occurrence of membrane perforation. The following adverse events were recorded: membrane perforation (7.2%), acute sinusitis (0.9%), implant displacement into the sinus cavity (0.7%), oro-antral fistula (0.2%), and benign paroxysmal positional vertigo (0.5% of osteotome cases). A strong direct correlation between sinus membrane perforation and bucco-palatal sinus width (p = .000) was demonstrated.

CONCLUSIONS

Early implant failure after transcrestal sinus elevation showed significant direct correlation with bucco-palatal maxillary sinus width and the presence of membrane perforation. Sinus membrane perforation was strongly associated with bucco-palatal sinus width (extremely low perforation rate in narrow and much higher incidence in wide sinuses).

Does new bone formation vary in different sites within the same maxillary sinus after lateral augmentation? A prospective histomorphometric study

OBJECTIVE

The aim of this study was to evaluate histomorphometric outcomes of lateral maxillary sinus augmentation in different areas of the same cavity and to correlate results to bucco-palatal sinus width (SW) and residual bone height (RBH).

MATERIAL AND METHODS

Patients needing maxillary sinus floor elevation (RBH <5 mm) to insert two nonadjacent implants were treated with lateral augmentation using a composite graft. Six months later, two bone-core biopsies (mesial/distal) were retrieved in implant insertion sites. SW and RBH were measured on cone beam computed tomography, and correlations between histomorphometric and anatomical parameters were evaluated by multivariate linear regression analysis.

RESULTS

Twenty patients underwent sinus augmentation, and eighteen were included in the final analysis (two dropouts for membrane perforation). Mean newly formed mineralized tissue percentage (%NFMT) after 6 months in mesial and distal sites was 17.5 ± 4.7 and 11.6 ± 4.7, respectively (p = .0004). Multivariate linear regression showed a strong negative correlation between SW and %NFMT (β coefficient=-.774, p < .0001) and no correlation between RBH and %NFMT (β coefficient =-.038, p = .825).

CONCLUSIONS

The present study confirms that %NFMT after lateral sinus augmentation occurs at different rates in different anatomical areas of the same maxillary sinus, showing a strong negative correlation with SW, whereas no influence of RBH was observed. Clinicians should regard SW as a guide for graft selection and to decide duration of the healing period. Researchers should consider SW as a predictor variable, when comparing regenerative outcomes of different biomaterials by using maxillary sinus as an experimental model.

Radiographic and Histomorphometric Evaluation of Biomaterials Used for Lateral Sinus Augmentation: A Systematic Review on the Effect of Residual Bone Height and Vertical Graft Size on New Bone Formation and Graft Shrinkage

The aim of the present systematic review was to investigate the effect of residual bone height (RBH) and vertical bone gain on new bone formation (NBF) and graft shrinkage after lateral sinus lifts using different biomaterials.

METHODS

An electronic search was conducted on three databases to identify randomized controlled trials (RCTs) published until January 2021 with at least one follow-up at 6 months and at least five patients treated, comparing biomaterials used for maxillary sinus augmentation with a lateral approach. Graft volumetric changes, RBH, vertical bone gain, implant failure, and post-operative complications were evaluated. The risk of bias was assessed using the Cochrane tool.

RESULTS

We used 4010 identified studies, of which 21 were RCTs. Overall, 412 patients and 533 sinuses were evaluated. Only three publications had an overall low risk of bias. After 6 months, xenograft (XG) showed the least volume reduction (7.30 ± 15.49%), while autogenous graft (AU) was the most reabsorbed (41.71 ± 12.63%). NBF appeared to not be directly correlated with RBH; on the contrary, the overall linear regression analysis showed that NBF significantly decreased by 1.6% for each mm of postoperative vertical graft gain. This finding suggests that the greater the augmentation, the lower the NBF. A similar tendency, with a regression coefficient even higher than the overall one, was also observed with alloplast (AP) and XG.

CONCLUSIONS

The present results suggested that NBF was essentially independent of preoperative bone height. On the contrary, the smaller the volume was of the graft placed, the higher the amount of new bone formed, and the smaller the graft shrinkage was. Minimizing the augmentation volume might be beneficial to graft healing and stability especially when using AP and XG.

Sinus augmentation - autograft vs. fresh frozen allograft: Bone density dynamics and implant stability

OBJECTIVES

Compare bone density changes and initial implant stability following sinus augmentation with autogenous bone (AB) vs. fresh frozen bone (FFB).

MATERIALS AND METHODS

Randomized, prospective, split mouth study. Sinus augmentation executed using either AB or FFB. Dental implants were inserted after 6 months of healing. Implant dimensions and insertion torques were recorded. Prostheses were delivered 6 months thereafter. All patients had computerized tomography (CT) scans 1 week (T1) and 6 months (T2) after initial bone grafting. Third CT (T3) was taken 12 months after prosthesis delivery. Data from CT scans was used to analyze bone density at each period.

RESULTS

A total of 15 patients (8 males, 7 females) following bilateral sinus augmentation procedures, were included. Mean age was 54 ± 5 years (range 48-60 years). All patients had 3 CT examinations. The initial augmented AB density was higher than the initial FFB density. Nevertheless, density differences between the two groups were not statistically significant at any time frame. At T2 density of both grafts showed a statistically significant increase. A significant increase from T2 to T3 was noted only for the FFB group. Implant insertion torque was significantly higher in the FFB group. Insertion torque ≥32 N/cm was achieved in significantly more patients in the FFB group.

CONCLUSION

The use of FFB for sinus augmentation is a reliable option of graft material. The newly formed bone quality performance, evaluated by CBCT density, is as good as AB, allowing predictable initial implant stability and osseointegration. Unnecessary morbidity associated with AB harvesting is thus avoided.

Effect of amount of biomaterial used for maxillary sinus lift on volume maintenance of grafts

Background

Regardless of the kind of biomaterial used for the graft, it is clear that, over time, the graft undergoes dimensional changes that could influence the final bone volume obtained, which could alter the stability of the installed implants. The aim of the present study was to compared and correlated the graft behavior with the amount (in grams) of xenogeneic and alloplastic biomaterials used in grafts for maxillary sinus lift.

Material and Methods

This retrospective cohort study used 148 CBCT images of 74 grafts from 68 maxillary sinuses lift patients in a university, post-graduate clinic. The weights of biomaterials, categorized in intervals according to amount used, were correlated with the graft volumes at V1 (10 days) and V2 (180 days). Kruskal-Wallis test was used to evaluate the possible bias effect of weight on graft maintenance.

Results

Mean weights of biomaterials used were: Bio-Oss Small® (1.58g); Bio-Oss Large® (1.35g); Endobon® (0.72g); BoneCeramic®+Emdogaim® (0.96g); Cerasorb® (1.13g) and Osteogen® (2.70g). No significant differences (p>0.05). Were found for the influence of these mean amounts in graft maintenance: Bio-Oss Small® (18); Bio-Oss Large® (10); Endobon® (17); BoneCeramic®+Emdogaim® (10); Cerasorb® (11); and Osteogen® (08) at V1 and V2. However, when biomaterials were categorized by intervals, all Cerasorb® interval groups showed statistically significant differences (p<0.001) in graft volume at V2.

Conclusions

The amounts of the biomaterials used could influence the final volume; depending on the biomaterial characteristics. Implant installation was possible with all studied grafts, although graft volume shrinkage should be considered when selecting biomaterial for sinus lift.

Key words:Biocompatible materials; cone beam computed tomography; maxillary sinus; hydroxyapatites.

Radiological and histological evaluation of horizontal ridge augmentation using corticocancellous freeze-dried bone allograft with and without autogenous bone: A randomized controlled clinical trial

PURPOSE

The purpose of this study was radiological and histological evaluation of horizontal ridge augmentation using corticocancellous freeze-dried bone allograft (FDBA) with and without autogenous bone (AB).

MATERIALS AND METHODS

The present research was conducted on 42 patients (27 females and 15 males) with insufficient width of edentulous ridge. The patients were randomly assigned into two groups, FDBA alone + collagen membrane (n = 21) and the combined FDBA and AB + collagen membrane (n = 21). The horizontal alveolar ridge dimensions were measured using cone-beam computerized tomography before and 6 months after alveolar ridge augmentation. At the time of insertion of implants, biopsy of new bone was taken from 11 patients in each group and was analyzed histologically. The obtained data were statistically analyzed with paired t test and two-sample t test. The registration number was IRCT201109165305N3.

RESULTS

The mean ± SD ridge width gain after 6 months at the distance of 0, 2, 4, and 6 mm from crest of alveolar ridge was 2.78 ± 1.44, 3.05 ± 1.21, 2.82 ± 1.62, and 2.23 ± 1.95 mm in the FDBA group and 2.40 ± 1.60, 3.10 ± 1.80, 3.60 ± 1.87, and 2.65 ± 2.39 mm in the combined group, respectively, which was statistically significant in both groups using paired t test (P < .001). However, the difference between two groups analyzed by two-sample t test was not statistically significant (P > .05). Amount of new bone generation, remained particles, and connective tissue was not statistically different between two groups (P = .367, P = .428, and P = .598, respectively).

CONCLUSION

Based on the results of this study, corticocancellous FDBA granules along with collagen membrane can successfully be used for horizontal augmentation of edentulous ridge, and adding AB to the granules of FDBA does not significantly increase the quality and quantity of regenerated bone.

Bone formation following sinus grafting with an alloplastic biphasic calcium phosphate in Lanyu Taiwanese mini-pigs

BACKGROUND

To evaluate the new bone formation after grafting with a synthetic biphasic calcium phosphate in sinuses with minimal bone height, the alloplastic and xenograft materials were compared after grafting into Lanyu Taiwanese mini-pig sinuses via split-mouth design.

METHODS

In six mini-pigs, synthetic hydroxyapatite/tricalcium phosphate (HA/TCP) particles were inserted into one of the sinus cavities using the extra-oral approach, where deproteinized bovine bone mineral (DBBM) particles were placed contralaterally. Fluorescent bony labels of Alizarin and Calcein green were delivered at weeks 4 and 8, respectively. Animals were sacrificed at week 12 and the augmented tissues were evaluated by cone-beam computed tomography, microcomputed tomography, and histology.

RESULTS

By radiographic examination, the mean thicknesses of sinus cortexes for DBBM and HA/TCP groups were similar (0.35 versus 0.38 cm) and the mean volumes augmented were also indifferent (1.29 versus 1.64 cm³ ). The distributions of bones, residual particles, and non-mineralized tissues in augmented masses between groups were undistinguishable. Under microscopy, however, macroporosities of osteons were filled with HA/TCP residual particles, whereas the newly formed bones lay on top of DBBM particle surfaces. Although the mineral deposition rates between groups were indifferent, the mean labeled surface in the HA/TCP group was significantly greater than those in the DBBM group at week 4 (35.16% versus 14.00% for HA/TCP and DBBM, respectively) but less than that at week 8 (19.33% versus 39.16%, respectively).

CONCLUSION

Sinus augmentation with synthetic HA/TCP and DBBM exhibited similar effectiveness in new bone formation.

Influence of residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone

OBJECTIVE

To evaluate the influence of the posterior residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone.

MATERIAL AND METHODS

Bilateral sinus bone augmentation was performed using anorganic bovine bone in 20 patients with residual bone height <2 mm in at least one site on each side. Trephine samples were removed at the implant insertion site 8 months after the grafting procedure, and histological and histomorphometric analyses were performed to examine the relative amount (%) of new bone, anorganic bovine bone, and soft tissue in the grafted area. Based on cone beam computed tomography evaluation, the sites of implant insertion were classified according to sinus width into narrow, average, and wide, and according to residual bone height into ≤2 and >2 mm.

RESULTS

A total of 146 implants were installed and 103 biopsies were evaluated. New bone formation in sites classified as narrow (69 sites), average (19 sites), and wide (15 sites) was 28.5% ± 9.24, 28.9% ± 8.61, and 30.3% ± 7.80, respectively. The mean posterior maxillary residual bone height was 4.0 ± 2.43 mm, and 26 and 77 sites were classified as ≤2 and >2 mm, respectively. New bone formation was 26.2% ± 9.10 and 29.8% ± 8.67 for residual bone height ≤2 and >2 mm, respectively. The differences were non-significant.

CONCLUSIONS

Within the limitations of the present study, posterior residual bone height and sinus width were not factors with influence on new bone formation in sinuses grafted exclusively with anorganic bovine bone after 8 months of healing.

New bone formation after transcrestal sinus floor elevation was influenced by sinus cavity dimensions: A prospective histologic and histomorphometric study

OBJECTIVE

The aim of this multicenter prospective study was to analyze clinically and histologically the influence of sinus cavity dimensions on new bone formation after transcrestal sinus floor elevation (tSFE).

MATERIAL AND METHODS

Patients needing maxillary sinus augmentation (residual crest height <5 mm) were treated with tSFE using xenogeneic granules. Six months later, bone-core biopsies were retrieved for histological analysis in implant insertion sites. Bucco-palatal sinus width (SW) and contact between graft and bone walls (WGC) were evaluated on cone beam computed tomography, and correlations between histomorphometric and anatomical parameters were quantified by means of forward multiple linear regression analysis.

RESULTS

Fifty consecutive patients were enrolled and underwent tSFE procedures, and forty-four were included in the final analysis. Mean percentage of newly formed bone (NFB) at 6 months was 21.2 ± 16.9%. Multivariate analysis showed a strong negative correlation between SW and NFB (R²  = .793) and a strong positive correlation between WGC and NFB (R²  = .781). Furthermore, when SW was stratified into three groups (<12 mm, 12 to 15 mm, and >15 mm), NFB percentages (36%, 13% and 3%, respectively) resulted significantly different.

CONCLUSIONS

This study represented the first confirmation based on histomorphometric data that NFB after tSFE was strongly influenced by sinus width and occurred consistently only in narrow sinus cavities (SW <12 mm, measured between buccal and palatal walls at 10-mm level, comprising the residual alveolar crest).

Dehydrothermally Cross-Linked Collagen Membrane with a Bone Graft Improves Bone Regeneration in a Rat Calvarial Defect Model

In this study, the bone regeneration efficacy of dehydrothermally (DHT) cross-linked collagen membrane with or without a bone graft (BG) material was evaluated in a critical-sized rat model. An 8-mm-diameter defect was created in the calvaria of 40 rats, which were randomized into four groups: (1) control; (2) DHT; (3) BG; and, (4) DHT + BG. Evaluations were made at 2 and 8 weeks after surgery using micro-computed tomographic (micro-CT), histological, and histomorphometric analyses. Micro-CT analysis showed an increase in the new bone volume (NBV) of the BG and DHT + BG groups at 2 weeks after surgery, representing a significant difference (p < 0.05). At 8 weeks after surgery, the NBV increased in all four groups. However, larger NBVs were observed in the BG and DHT + BG groups, and a significant difference was no longer observed between the two groups. Histologic analysis demonstrated that the graft materials sustained the center of the defect in the BG and DHT + BG groups, which was shown in histomorphometric analysis as well. These results suggest that DHT membrane is a safe biomaterial with adequate tissue integration, and has a positive effect on new bone formation. Moreover, the best effects were achieved when DHT was used in conjunction with BG materials.

Comparison between mineralized cancellous bone allograft and an alloplast material for sinus augmentation: A split mouth histomorphometric study

BACKGROUND

Several grafting materials have been used in sinus augmentation procedures including autogenous bone, demineralized freeze-dried bone, hydroxyapatite, β-tricalcium phosphate, anorganic deproteinized bovine bone, and combination of these and others. Yet, the issue of the optimal graft material for sinus floor augmentation is controversial.

PURPOSE

This prospective, randomized split-mouth study was undertaken to histomorphometrically compare a biphasic calcium phosphate (BCP) alloplastic bone substitute and a human bone mineral allograft (freeze-dried bone allograft, FDBA) in patients undergoing bilateral maxillary lateral sinus floor augmentation.

MATERIAL AND METHODS

Apico-coronal core biopsies were harvested at 9 months from 26 bilateral sites in 13 treated patients. Specimens were processed for histological and histomorphometrical analyses.

RESULTS

Newly formed bone (NB) was evident in all specimens with values of 27.5% and 24.0% at the FDBA and BCP sites, respectively (P = .331). The residual graft particle values were 12.5% and 25.4% (P = .001), and the connective tissue values were 60.0% and 50.6%, respectively. The osteoconductive value was 52.6% for the FDBA and 26.7% for the alloplast (P = .001). The values for the measured residual graft particles, connective tissue, and osteoconductivity, but not for NB, showed highly significant differences between the two groups. All sections in the alloplast material showed evidence of a light chronic inflammatory infiltrate, mainly comprising lymphocytes and multinucleated giant cells.

CONCLUSIONS

Both graft materials are suitable for sinus floor augmentation, with the allograft material being more osteoconductive.

The Maxillary Sinus Floor Elevation Using a Poly-L-Lactic Acid Device to Create Space Without Bone Graft: Case Series Study of Five Patients

Maxillary sinus floor elevation using autologous or alloplastic bone grafting is often performed for implant treatment of maxillary molars; however, issues related to the donor site and complications such as infection have been reported. We performed maxillary sinus floor elevation using poly-L-lactic acid (PLLA) as a space-making material in patients with an insufficient bone mass (&lt;3 mm) for simultaneous implantation between the alveolar crest and floor of the maxillary sinus and evaluated the newly formed bone. Conventional antrostomy of the maxillary sinus from the lateral wall was performed, and PLLA was placed on the floor of the maxillary sinus after elevating the sinus membrane. Six months after surgery, the bone mass and density were measured using quantitative computed tomography, and histological evaluation was performed. No complications were recorded. Radiological findings showed a bone-like radiopaque appearance, and histological examination revealed new bone formation in all patients. In cases with insufficient bone mass prior to simultaneous implant placement, this method of maxillary sinus augmentation allows for sufficient bone augmentation without bone grafting.

Effectiveness of platelet-rich plasma as an adjunctive material to bone graft: a systematic review and meta-analysis of randomized controlled clinical trials

The use of platelet-rich plasma (PRP) has become a strategic therapy in tissue regeneration medicine. PRP represents a good source of growth factors. Due to this property, it has been considered a reliable adjunctive material in bone augmentation procedures, such as the sinus lift technique. The aim of this review was to assess the scientific evidence on the effectiveness of PRP as an adjunctive material in the sinus floor elevation technique. The following databases were searched for relevant published studies: Medline, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, CINAHL, Science Direct, ISI Web of Knowledge, and SCOPUS. Only randomized controlled clinical trials comparing a group receiving PRP as an adjunctive material to a control group without PRP, involving adult human subjects (age >18 years) with no systemic disease, were included. Of the studies identified, only one reported a significant difference in bone augmentation in favour of the adjunctive use of PRP, while four studies did not find any significant difference. None of the studies included reported a significant difference in the implant survival rate. Further randomized clinical trials are needed to clarify the effectiveness of adjunctive PRP.

Bone regeneration of macropore octacalcium phosphate-coated deproteinized bovine bone materials in sinus augmentation: a prospective pilot study

OBJECTIVE

To investigate the osteogenic potential of macropore octacalcium phosphate (OCP)-coated deproteinized bovine bone materials (DBBMs) in sinus augmentation.

STUDY DESIGN

Macropore OCP-coated DBBM was manufactured from bovine bone by thermal and chemical processing. Sinus grafts of a lateral window approach with experimental bone were conducted in 10 patients. At 6 months after surgery, a total of 10 specimens were obtained from 10 patients. But, 4 of them were excluded because the amount of specimens was not enough for evaluation. Morphological investigation under scanning electron microscopy and histological evaluation were performed.

RESULTS

OCP was evenly attached to the surface of the experimental graft and showed a relatively large pore size (300-400 μm) compared with Bio-Oss (100-200 μm). New bone comprised 23.49% (± 0.10), and residual graft material comprised 15.39% (± 0.06) in bone specimens.

CONCLUSION

A macropore-sized design and OCP coating could present a favorable environment for new bone formation in maxillary sinus grafts.

Lateral Bone Window Closing Technique with Poly-L-Lactic Acid (PLLA) Membrane in the Augmentation of the Maxillary Sinus without Grafting Material: Evaluation of Bone Healing in a Rabbit Model

BACKGROUND

When augmenting the maxillary sinus without grafting material, the method used to cover the bony window is a subject of debate.

PURPOSE

The purpose of this study was to evaluate the poly-L-lactic acid (PLLA) membrane as closing material of the lateral window in a maxillary sinus augmentation without bone grafting.

MATERIALS AND METHODS

Augmentation of the maxillary sinus without grafting material and installation of titanium screws that fix the Schneiderian membrane were performed in 18 Japanese male white rabbits. The bony window was covered with a collagen membrane or PLLA membrane or no membrane. The animals were sacrificed at 4 or 8 weeks. New bone volume was calculated radiologically using microcomputed tomography (micro-CT). The samples were analyzed histologically after toluidine blue staining.

RESULTS

No significant differences were observed in the new bone volume, as measured by micro-CT. However, histomorphometric analysis demonstrated the superiority of the PLLA membrane in new bone formation compared with the collagen membrane.

CONCLUSION

The PLLA membrane is a suitable material to be applied for tissue regeneration in this animal model.

Platelet-Rich Fibrin in Maxillary Sinus Augmentation: A Systematic Review

The aim of this study was to systemically assess the efficacy of platelet-rich fibrin (PRF) on maxillary sinus augmentation using the lateral approach. A PubMed search and a hand search of relevant journals and the bibliographies of selected articles were performed. Clinical studies using PRF with open maxillary sinus augmentation were included. The search provided 290 titles; only 8 studies fulfilled the inclusion criteria. Identified studies showed heterogeneity regarding surgical technique, grafting material, implant placement time, protocol, outcome measures, healing time for biopsy, and implant placement, as well as follow-up period. From the 8 identified studies, 3 studies used PRF as a sole filling material, whereas the other 5 studies used PRF with bone substitutes. PRF showed promising results as a sole filling material for sinus lift with simultaneous implant placement, and PRF seemed to accelerate maturation of a demineralized freeze dried bone allograft. Conversely, it had no effect on deproteinized bovine maturation. PRF fibrin membranes represent an easy and successful method to cover the sinus membrane or osteotomy window.

Impact of human maxillary sinus volume on grafts dimensional changes used in maxillary sinus augmentation: a multislice tomographic study

PURPOSE

To assess the influence of complete maxillary sinus volume on the dimensional changes of different grafts used in maxillary sinus lift.

MATERIALS AND METHODS

Analysis of 50 surgical procedures of maxillary sinus lift performed on 43 subjects using different grafting materials: fresh frozen allogenic particulated bone (11), hydroxyapatite (Endobon(®)) (17), 60% hydroxyapatite + 40% beta-tricalcium phosphate (Bone Ceramic(®)) (12) and Bone Ceramic(®) + Emdogain(®) (10). One hundred and fifty multislice tomographic images of the maxillary sinus were obtained using the software Syngo CT 2011 A VOLUME, measuring complete maxillary sinus volume (T0) and dimensional changes of different graft materials during periods of 15 days (T1) and 180 days (T2). The factor studied was the influence of maxillary sinus volume on the dimensional changes of different graft materials used in maxillary sinus lift in patients with posterior edentulism. Data obtained were assessed using the Student's t-test and Pearson's correlation coefficient.

RESULTS

No correlation (r 0.112) between the total maxillary sinus volume and the dimensional changes of the different graft materials used in this study was observed (P > 0.05).

CONCLUSION

This study demonstrated that there is no sufficient evidence to support the thesis that the volume of the maxillary sinus influences the contraction of the grafts, at least on sample or the biomaterials evaluated in this cohort study.

Volumetric changes after sinus augmentation using blocks of autogenous iliac bone or freeze-dried allogeneic bone. A non-randomized study

OBJECTIVES

To compare volumetric bone changes after sinus augmentation for implant positioning using blocks of autogenous iliac bone or freeze-dried allogeneic bone (FDBA) from the hip. Variables were compared between the two sources and for each surgical procedure at set times (pre- and post-augmentation procedure).

PATIENTS AND METHODS

A non-randomized retrospective chart review of 7 patients who had autogenous and 7 allogeneic block grafts was carried out (1 procedure per patient). Analysis of Computer Tomographic (CT) data of maxillary sinuses, acquired with high-speed, double-detector CT scanner, was performed using dentascan software. The change between the preoperative (T0) and postoperative volume was measured at 4-6 months (T2) and 1.5 year after transplantation (T3). Annual- and overall-rates of bone change were calculated for the two sources.

RESULTS

All patients were partially edentulous with a residual maxillary floor thickness in the planned implant insertion sites of 2.7 (0.5) mm and 2.8 (0.5) mm for allogeneic and autogenous procedures respectively. From identical intraoperative volume of grafts (2.25 cc at T1), volumetric changes were recorded at T2 and T3. The final volume of the grafts was 1.44 cc for allogeneic group and 1.78 cc for the autogenous group. Significant volumetric changes over time of transplanted grafts for both sources (23% for autograft and 18% for allograft) were found at T2. At 1.5-years post-operatively comparisons of volumes and rates of bone loss between sources were not statistically significant. No failure was recorded for either bone grafts or dental implants.

CONCLUSIONS

Short-term sinus grafting procedure for dental implant placement performed with FDBA showed an outcome close to that reported for autogenous bone. Volumetric changes were comparable between the sources. These data suggest that performing maxillary sinus augmentation with dry-preserved bone allogeneic materials in block form could be considered even when the residual floor thickness is less than 3 mm.

Lateral Augmentation of the Maxilla and Mandible Using Framework Technique With Allogeneic Bone Grafts

This study aimed to evaluate the effectiveness of lateral ridge augmentation in 36 patients with severely atrophic alveolar ridge using allogeneic bone grafts in a framework technique. A thinned allogeneic cortical graft was screwed to the alveolar ridge, leaving a hollow space that was filled with particulated allogeneic cortical bone. Thirty-six patients who received surgical lateral block augmentation using allogeneic bone grafts were involved in this study. Implants were placed in a second session after a mean time of 6.3 months. The surgical technique and the reasons for failure of surgery in three patients are described. Additionally, properties of allogeneic bone grafts are reviewed. In 33 patients, dental implants were successfully installed and continued to be well maintained at the last follow-up (91.7% success). In three patients, dental implants could not be installed (8.3% failure) as the graft was lost because of wound dehiscence; however, repeat surgery was successfully carried out in all three. The use of allogeneic bone grafts in lateral ridge augmentation of the maxilla and mandible showed successful clinical results. It seems to be a reliable material for reconstructing a severely atrophic alveolar ridge. It presents a good alternative to autogenous bone regarding augmentation because it offers good ossification, less morbidity, unlimited availability and shorter duration of surgery, and lower costs.

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.

Allograft for maxillary sinus floor augmentation: a retrospective study of 90 cases

PURPOSE

The aim of this study is to demonstrate the clinical applicability and efficacy of an allograft for maxillary sinus augmentations in patients requiring placement of dental implants.

PATIENTS AND METHODS

Sixty consecutive patients underwent a total of 90 sinus augmentations. Twenty-nine were women and 31 men, with a mean age of 54 years. Twenty-six patients received a bilateral procedure and 34 unilateral. All cases were treated with the lateral wall technique. Allograft consisted of demineralized freeze-dried blocks in 6 cases, particulate in 82 cases, and a combination of both in 2 cases. In 30 patients, it was combined with platelet-rich plasma. A total of 84 implants were inserted. Bone samples of grafted areas were obtained in two patients for histological examination.

RESULTS

Seventy-three implants were clinically successful at the reentry time. Eleven implants in seven patients were removed between 15 days and 6 months after their placement. Seven of these implants were replaced and received prostheses as well, for an overall postloading success rate of 95.2%. Follow-up for all patients after final restoration was between 12 and 96 months. Specimen's histological evaluation revealed bone formation and evidence of inflammatory infiltrate.

CONCLUSIONS

Based on the findings of this study, it can be suggested that the use of the demineralized freeze-dried bone allograft from the Banco de Huesos y Tejidos Fundación Cosme y Damian for sinus augmentation is effective and constitutes a feasible therapeutic alternative for implant placement.

Radiographic and histologic evaluation of platelet-rich plasma and bovine-derived xenograft combination in bilateral sinus augmentation procedure

There is currently a great interest regarding the use of platelet-rich plasma (PRP) in combination with various bone graft materials in sinus lift procedures. The purpose of this study was to assess and compare the radiographic and histological results of sinus augmentation procedures following treatment with PRP/bovine-derived xenograft (BDX) vs. BDX/collagen membrane. Using a split mouth design, 10 patients, with ≤5 mm of residual alveolar bone in the vertical direction, were treated with PRP/BDX or BDX/collagen membrane. At 8 months after surgery, both graft materials led to a satisfactory increase in vertical dimensions of bone. Bone biopsies were taken from the augmented sites during the implant placement. Histological analysis demonstrated that majority of the trabecula contained orderly layered lamellar bone in the PRP/BDX group, whereas mainly woven bone with a haphazard arrangement of collagen fibers were noticed in the BDX /collagen membrane group. It can be concluded that both combinations resulted with a satisfactory bone height, but more prominent and mature bone formation was observed at sites treated with PRP/BDX.

Histologic and Histometric Evaluation of Bovine Cancellous Bone and Beta-Tricalcium Phosphate 45 Months After Grafting in Maxillary Sinus

The aim of this report is to determine the long-term histologic and histometric evaluation of beta-tricalcium phosphate (beta-TCP) and bovine cancellous bone grafted into the left maxillary sinus of a patient in order to augment the sinus floor to prepare it for receiving an implant. Beta-TCP and bovine cancellous bone (BCB) were grafted into the left maxillary sinus at the extracted sites of maxillary left first and second molars of a 62-year-old male patient. Using osteotome technique, 45 months later, core biopsies were taken for histologic and histometric comparison of the newly formed bone. Histometric and histologic evaluation of both specimens revealed a normal maxillary bone structure with 23.08% calcified bone and 76.92% marrow and connective tissue for the beta-TCP grafted site, and 24.81% calcified bone with 75.19% marrow and connective tissue for the BCB grafted site. No residual grafting material was seen in either specimen. Both beta-TCP and BCB were completely resorbed and replaced by new bone 45 months after grafting. Histologic results of the newly formed bone were similar for both grafting materials.

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.

Clinical and histologic outcomes after the use of a novel allograft for maxillary sinus augmentation: a case series

PURPOSE

To document the clinical and histologic outcomes of sinus augmentation using a novel allogenic bone substitute as a sole grafting material.

MATERIALS

Patients in need of sinus augmentation before implant placement were recruited for this study. Sinus augmentation procedures were performed following a lateral approach, using a freeze-dried allograft as the only grafting material. Patients were followed up postoperatively for 6 months. Plaque score, wound healing, and patient discomfort were recorded at each follow-up visit. Implants were placed between 6 and 7 months after sinus augmentation and restored 6 months later. Bone core biopsy specimens were harvested at the time of implant placement and processed for histologic and histomorphometrical analysis. Vital bone, remaining allograft (RA) particles, and nonmineralized tissue percentages were assessed on each sample. Results were expressed as mean percentages with SD.

RESULTS

Of the 23 sinus patients, 20 patients underwent sinus augmentation surgery. All patients had satisfactory postoperative healing in the absence of complications. A total of 39 implants were placed. One implant failed and was replaced 3 months later. Histologic analysis revealed the presence of well-organized lamellar bone, in direct contact with RA particles. Mean vital bone was 23.02 +/- 19.11%, mean RA was 22.25 +/- 20.30%, and average nonmineralized tissue was 54.73 +/- 13.51%.

CONCLUSION

Clinical and histologic findings support the suitability of an allograft consisting of a combination of cortical and cancellous chips for sinus augmentation procedures.

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.