Effect of autologous growth factors in maxillary sinus augmentation: a systematic review

Effectiveness of concentrated growth factors with or without grafting materials in maxillary sinus augmentation: a systematic review

Concentrated Growth Factor (CGF) is a highly effective biomaterial known for its ability to promote tissue regeneration. While it's been studied extensively in intraoral procedures and bone grafting, its benefits in maxillary sinus lifting lack substantial evidence. This review aimed to evaluate CGF's effectiveness in maxillary sinus augmentation, focusing on clinical, radiographic, and histological outcomes.A comprehensive literature search was conducted across PubMed, Scopus, Web of Science, Google Scholar, and Cochrane Library databases using specific mesh terms and keywords and adhered to PRISMA guidelines. Studies up to March 2024 involving transcrestal or lateral maxillary sinus floor elevation with CGF, either alone or in combination with grafting materials, were included.Out of 783 publications, 13 studies met the eligibility criteria. The review assessed CGF's role in minimizing postoperative complications, enhancing new bone formation, and improving implant survival. Despite data variability among studies, the majority reported that CGF positively influenced maxillary sinus augmentation outcomes.While more robust randomized clinical trials are required to draw definitive conclusions, initial results are promising, and the findings suggest that CGF utilization in maxillary sinus augmentation seems to enhance clinical outcomes by promoting vascularization and regeneration at the surgical sites and improving both the quality and quantity of newly formed sinus bone. Furthermore, it exhibits potential for improving postoperative sequelae and achieving high implant survival rates.

Navigating the combinations of platelet-rich fibrin with biomaterials used in maxillofacial surgery

Platelet-rich fibrin (PRF) is a protein matrix with growth factors and immune cells extracted from venous blood via centrifugation. Previous studies proved it a beneficial biomaterial for bone and soft tissue regeneration in dental surgeries. Researchers have combined PRF with a wide range of biomaterials for composite preparation as it is biocompatible and easily acquirable. The results of the studies are difficult to compare due to varied research methods and the fact that researchers focus more on the PRF preparation protocol and less on the interaction of PRF with the chosen material. Here, the literature from 2013 to 2024 is reviewed to help surgeons and researchers navigate the field of commonly used biomaterials in maxillofacial surgeries (calcium phosphate bone grafts, polymers, metal nanoparticles, and novel composites) and their combinations with PRF. The aim is to help the readers select a composite that suits their planned research or medical case. Overall, PRF combined with bone graft materials shows potential for enhancing bone regeneration both in vivo and in vitro. Still, results vary across studies, necessitating standardized protocols and extensive clinical trials. Overviewed methods showed that the biological and mechanical properties of the PRF and material composites can be altered depending on the PRF preparation and incorporation process.

Effectiveness of Autologous Platelet Concentrates in the Sinus Lift Surgery: Findings from Systematic Reviews and Meta-Analyses

Maxillary sinus augmentation is one of the most predictable procedures for the rehabilitation of the posterior maxilla. The current overview aimed to summarize the findings provided by systematic reviews (SRs) and meta-analyses on the effectiveness of autologous platelet concentrates (APCs) in sinus lift and to assess the methodological quality of the included SRs. Three electronic databases have been explored. SRs and meta-analyses addressing the effectiveness of APCs in sinus lift technique were included. Clinical, radiographic and histomorphometric findings were considered for APCs as solely grafting materials and APCs in combination with biomaterials. Outcomes were implant survival rate (ISR), implant stability (IS), implant failure (IF), postoperative complications, histomorphometric findings, radiographic bone gain, bone volume and bone density. The methodological quality of the included SRs was assessed using the updated version of "A Measurement Tool to Assess Systematic Review" (AMSTAR-2). Thirty SRs were included. The methodological quality of the included reviews ranged from critically low (3 studies) to high (9 studies). The included SRs showed favorable clinical outcomes, short-term new bone formation and no biological complications when APCs were used both as solely graft material or in combination with other biomaterials. However, no significant additional effects in the long-term period were observed. APCs did not add any further positive effects compared to the physiological healing derived by the natural blood clot. The current overview of SRs highlighted the need for high-quality SRs evaluating the role of APCs in sinus lift though network meta-analyses, in order to identify the most powerful material for sinus lift augmentation. The use of APCs improves the healing of soft tissues and the postoperative quality of life in the short-term period. Thus, its application can be recommended.

Combined Application of Dentin Noncollagenous Proteins and Odontogenic Biphasic Calcium Phosphate in Rabbit Maxillary Sinus Lifting

BACKGROUND

Teeth can be used as a raw material for preparing bone substitutes due to their similar chemical composition to bone. The objective of our study was to evaluate the effect of odontogenic biphasic calcium phosphate (BCP) incorporating dentin noncollagenous proteins (DNCPs) on osteogenesis and stability in maxillary sinus augmentation.

METHODS

The composition, structure and morphology of the odontogenic BCP were tested by X-ray powder diffraction (XRD), Brunauer-Emmett-Teller, and scanning electron microscopy methods. The biocompatibility and osteoinduction of DNCPs and materials were examined in vitro and their bone regeneration capacity was verified in vivo.

RESULTS

The results showed that the cells adhered and proliferated well on the DNCP-loaded BCP scaffold. The odontogenic BCP and DNCPs promoted osteogenic differentiation of cells, The new bone formation in the BCP groups and DNCP subgroups was significantly higher than the new bone formation in the control, and the new bone quality was better. The bone regeneration effect of odontogenic BCP was similar to the effect of deproteinized bovine bone mineral, but β-TCP did not maintain the height and volume of bone reconstruction.

CONCLUSION

In conclusion, the combined application of DNCPs and odontogenic BCP is an effective strategy for tissue engineering osteogenesis in the maxillary sinus region. The biomimetic strategy could provide a new approach for patients requiring maxillary sinus lifting.

Bone-Regenerative Ability of Platelet-Rich Plasma Following Sinus Augmentation with Anorganic Bovine Bone: A Systematic Review with Meta-Analysis

BACKGROUND

The objective of this systematic review is to assess the effect of the adjuvant use of platelet-rich plasma (PRP) and its type on new bone formation by anorganic bovine bone during maxillary sinus floor augmentation procedure.

METHODS

PubMed, Cochrane Central Register of Controlled Trials, and Ovid databases were searched for relevant studies published up to 16 September 2021. Randomized clinical trials (RCTs) and non-randomized controlled clinical trials (CCTs) that reported data on the new bone formation (measured by histomorphometric analysis) were considered. Risk of bias and quality assessment of included studies were evaluated following the Cochrane Handbook for Systematic Reviews of Interventions and the Risk Of Bias In Non-randomised Studies of Interventions (ROBINS-I) tool. Strength of evidence was assessed following the approach of the Agency for Healthcare Research and Quality (AHRQ) through its evidence-based practice center (AHRQ EPC). The meta-analysis was based on the primary outcome of newly formed bone, for which the standard mean difference was calculated.

RESULTS

After the application of eligibility criteria, six clinical trials (three RCTs and three CCTs) covering 85 maxillary sinus floor elevation procedures were included. The pooled new bone formation value for PRP was 1.67 (95% CI: -0.15 to 3.49; I2: 86%), indicating the absence of significant effect. Plasma rich in growth factors (PRGF) was the pure PRP tested in five of the included studies. When sub-group (type of PRP) meta-analysis was performed, significantly higher new bone formation was observed in the PRGF group [2.85 (95% CI: 0.07 to 5.64; I2: 88%)] in comparison to the control group.

CONCLUSIONS

A beneficial effect on new bone formation after maxillary sinus floor elevation can be obtained when anorganic bovine bone is mixed with PRGF.

Radiographic Analysis of Graft Dimensional Changes after Lateral Maxillary Sinus Augmentation with Heterologous Materials and Simultaneous Implant Placement: A Retrospective Study in 18 Patients

Background: This investigation aimed to radiographically assess the variations of graft dimension following maxillary sinus augmentation by the lateral approach. Methods: Eighteen patients (seven males), with a mean age at surgery of 66.5 ± 9.8 (range 52−82) years, were unilaterally treated. Thirty-five dental implants were positioned in the posterior maxilla simultaneously to grafting with heterologous biomaterials. Intraoral radiographs taken at the time of surgery, after six months, and at the longest follow-up (up to nine years after implant placement) were analyzed. The following distances were measured: mesio-distal width of the graft, vertical distance from implant apex to most coronal level of the graft, distance from the mesial aspect of the (mesial) implant to the mesial graft extension; distance from the distal aspect of the (distal) implant to the distal graft extension, and graft height along the implant axis. The dimensional changes with respect to baseline, after six months and at the longest follow-up were calculated. Results: The patient-based mean follow-up was 38.3 ± 30.1 months (range 12−108 months). The mean residual bone height at the mesial and distal aspect of the implants was 3.19 ± 2.05 mm and 2.65 ± 1.60 mm, respectively (p = 0.38). The mean graft width at baseline was 27.95 ± 5.23 mm, and the mean graft width reduction was 10.2 ± 12.7% (2.98 ± 3.62 mm) and 11.3 ± 14.4% (3.36 ± 4.08 mm) at six months and at the latest follow-up. The change was significant at six months (p = 0.005), but did not show significant further variation (p = 0.11). On the mesial and distal aspect, the mean graft extension decreased by 1.56 ± 2.67 mm and 0.84 ± 2.71 mm at the latest follow-up. No significant difference between mesial and distal changes was found (p = 0.24), suggesting that the biomaterial is resorbed homogeneously on both sides. The mean graft height was 11.92 ± 2.53 mm at baseline and decreased by 9.3 ± 9.05% (1.11 ± 1.09 mm) at six months (p < 0.001). Non-significant further changes were found at the latest follow-up (p = 0.10). Conclusions: after early remodeling, heterologous bone substitutes showed a good dimensional stability in the mid-term for maxillary sinus augmentation.

Complications in sinus lifting procedures: Classification and management

Open and closed sinus lifting procedures are predictable methods to augment the bone needed for appropriate implant placement in the posterior maxilla in cases where available bone is limited. However, these techniques may give rise to complications and associated comorbidities. In the case of open sinus lifting, perforation of the Schneiderian membrane during osteotomy is the most common complication, with an incidence rate of around 20%-25%. Apart from those complications associated with oral surgery in general (such as swelling or hematoma), there are specific complications of open sinus lifting procedures that may arise less frequently (chronic rhinosinusitis, hemorrhage, or ostium blockage by overfilling) but which may nevertheless compromise the viability of the graft and/or the implants and cause substantial discomfort to the patient. Closed sinus lifting is a less invasive approach that allows transcrestal placement of the implants in cases where there is sufficient residual bone height. However, it may also be associated with specific complications, including membrane perforation, benign paroxysmal positional vertigo, and implant displacement to the sinus cavity. New technologies have been proposed to reduce these complications and comorbidities associated with conventional sinus lifting procedures, such as the use of piezoelectric devices and hydraulic sinus lift or reamer burs. The evidence supporting their effectiveness and safety, however, is still lacking. A detailed medical history together with a thorough radiographic and clinical examination are essential prior to any kind of bone regenerative augmentation involving the maxillary sinus. Moreover, it is recommended to employ the most appropriate surgical technique for the specific characteristics of the case and, at the same time, accommodating the experience and skills of the surgeon.

A retrospective preliminary histomorphometric and clinical investigation on sinus augmentation using enzyme-deantigenic, collagen-preserving equine bone granules and plasma rich in growth factors

Background

Enzyme-deantigenic equine bone (EDEB) is a substitute of autogenous bone. Mixing it with plasma rich in growth factors (PRGF) seems a viable option to achieve enhanced bone formation in alveolar bone augmentation surgeries. This retrospective study aims to first report the histomorphometric and clinical outcomes achieved when using the EDEB/PRGF mixture for performing sinus augmentation procedures followed by delayed implant placement.

Materials and methods

Records of 11 patients who underwent 14 sinus augmentation surgeries using EDEB/PRGF followed by delayed implant placement were retrospectively collected and analyzed to assess histomorphometric data concerning newly formed bone (NFB) and residual biomaterial (RB) recorded at implant placement, marginal bone loss (MBL) values of implants placed in the augmented sinuses, and implant and prosthetic success and survival rates.

Results

At 5.6 ± 1.1 months after grafting, NFB and RB were 34.0 ± 9.1% and 11.3 ± 2.2% respectively, and no histologic signs of inflammation or immune reaction were observed in any of the 34 bone biopsies being collected. Further, 86.5 ± 4.3 months after implant placement, MBL was 0.40 ± 0.07 mm. No implant or prosthesis failed, and the implant success and survival rates were 100%

Conclusions

Within the limitations of the present study, grafting EDEB/PRGF for lateral sinus augmentation and delayed implant placement seems to be safe. Compared to published data concerning EDEB alone, results of the present study do not suggest that the EDEB/PRGF combination may provide a histomorphometric or medium-/long-term clinical advantage.

Platelet rich plasma in oral and maxillofacial surgery from the perspective of composition

The application of platelet-rich plasma (PRP) in oral and maxillofacial surgery has been thoroughly studied in the last two decades. Currently, different types of PRP are applied in the clinical practice, being the presence or absence of leukocytes one of the classification criteria. However, there is poor evidence assessing the influence of the PRP composition in their efficacy. In this context, the aim of this narrative review is to compile the existing evidence covering the efficacy of PRP in oral and maxillofacial surgery, starting from a systematic literature search and to qualitatively describe the efficacy outcomes from the composition perspective. According to the results of this review, the application of PRP in oral and maxillofacial surgery is a potential strategy to improve soft- and hard-tissue regeneration, observing differences in the efficacy of PRP depending on its composition and the studied application. P-PRP (the absence of leukocytes) has been more consistent in achieving beneficial effects in alveolar ridge preservation, management of post-extraction complications, bone augmentation and temporomandibular joint disorders. For that, the composition and methodology used to prepare the PRP should be a critical point when evaluating the efficacy of PRP.

The Influence of Residual Alveolar Bone Height on Graft Composition after Maxillary Sinus Augmentation Using Two Different Xenografts: A Histomorphometric Comparative Study

AIM

To evaluate the hypothesis of a correlation between the preoperative residual alveolar bone height (RBH) and graft maturation after maxillary sinus floor augmentation procedures using two different bone substitutes.

METHODS

A total of 20 patients who underwent unilateral maxillary sinus floor augmentation with either mineralized deproteinized bovine bone (DBBM) or a xenograft enriched with polymer and gelatin (NBS) were included in this prospective study. Six months after sinus surgery, bone biopsies were harvested with a 3.2 mm diameter trephine bur, prior to dental implant placement. Histomorphometric analysis was performed, and the results were correlated with the individual RBH. Implants were loaded after 5 months of insertion, and 1-year implant success and marginal bone level change were assessed.

RESULTS

RBH was 2.17 ± 1.11 mm (range 0.5-3.5 mm) and 2.14 ± 0.72 mm (range 0.5-3.0 mm) in the NBS and DBBM group, respectively. The biopsy analyses for the DBBM group showed woven bone increases by 5.08% per 1-mm increment of RBH; medullary spaces decreased by 9.02%, osteoid decreased by 4.4%, residual biomaterial decreased by 0.34%, and lamellar bone increased by 5.68% per 1-mm increase of RBH. In the NBS group, samples showed woven bone increases by 8.08% per 1-mm increase of RBH; medullary spaces decreased by 0.38%; osteoid increased by 1.34%, residual biomaterial decreased by 0.58%, and lamellar bone decreased by 5.50% per 1-mm increase of RBH. There was no statistically significant difference in the correlation between RBH and lamellar bone, woven bone, and osteoid, independently of the material used. Implant success was 100% in both groups, and marginal bone loss was 1.02 ± 0.42 mm in DBBM and 0.95 ± 0.31 mm in the NBS group after the 1-year follow-up.

CONCLUSION

In spite of the absence of significance, the observed trend for woven bone to increase and medullary spaces to decrease when RBH increases deserves attention. Residual bone dimension might be a determinant in the bone graft maturation after maxillary sinus augmentation.

Three-dimensional bone evaluation after surgical treatment with plasma rich in growth factors of Medication Related Osteonecrosis of the Jaw (MRONJ): A report of 3 cases

Introduction

Medication Related Osteonecrosis of the Jaw (MRONJ) is an adverse effect of antiresorptive and antiangiogenic agents that consists of progressive bone destruction in the maxillofacial area. The purpose of this study is to analyze the effect on bone volume of a surgical protocol using plasma rich in growth factors (PRGF) for successfully treating MRONJ.

Methods

Three patients were treated combining surgical debridement with PRGF. Cone bean computed tomography scans were taken prior to surgery and 12 months after to measure bone volume changes. Biopsies were taken for histology analysis during surgery.

Results

All patients showed a complete soft tissue and bone healing with pain, discomfort, and neural symptoms resolution for a follow up period of 30 months. A total of 12 to 30% of bone volume gain was found at 12 months after surgery.

Conclusions

PRGF in combination with surgery may be effective in treating MRONJ. Future trials must be performed to confirm these results, including bone volume analysis.

Effectiveness of Platelet-Rich Fibrin as an Adjunctive Material to Bone Graft in Maxillary Sinus Augmentation: A Meta-Analysis of Randomized Controlled Trails

Purpose

To date, it remains unknown whether the addition of platelet-rich fibrin (PRF) to bone grafts actually improves the effectiveness of maxillary sinus augmentation. This study aimed to perform a meta-analysis to evaluate the efficacy of PRF in sinus lift.

Materials and Methods

PubMed, Embase, and the Cochrane Library were searched. Randomized controlled studies were identified. The risk of bias was evaluated using the Cochrane Collaboration tool.

Results

Five RCTs were included in our meta-analysis. Clinical, radiographic, and histomorphometric outcomes were considered. No implant failure or graft failure was detected in all included studies within the follow-up period. The percentage of contact length between newly formed bone substitute and bone in the PRF group was lower but lacked statistical significance (3.90%, 95% CI, -2.91% to 10.71%). The percentages of new bone formation (-1.59%, 95% CI, -5.36% to 2.18%) and soft-tissue area (-3.73%, 95% CI, -10.11% to 2.66%) were higher in the PRF group but were not significantly different. The percentage of residual bone graft was not significant in either group (4.57%, 95% CI, 0% to 9.14%).

Conclusions

Within the limitations of this review, it was concluded that there were no statistical differences in survival rate, new bone formation, contact between newly formed bone and bone substitute, percentage of residual bone graft (BSV/TV), and soft-tissue area between the non-PRF and PRF groups. Current evidence supporting the necessity of adding PRF to bone graft in sinus augmentation is limited.

The use of Platelet-rich Fibrin in the management of medication-related osteonecrosis of the jaw: A case series

Medication related osteonecrosis of the jaw (MRONJ) is characterized by exposed necrotic bone in the maxillofacial region that persists for more than eight weeks in patients taking antiresorptive or antiangiogenic drugs for bone metastasis or osteoporosis. The management of such condition depends on several factors, among which the staging of MRONJ. Though, a specific gold standard treatment has not been established to date. The aim of this case series is to describe the outcome of surgical treatment of MRONJ with the adjunct of Platelet-rich Fibrin (PRF). Eleven patients under therapy with alendronate underwent surgical removal of necrotic bone and debridement, followed by placement of PRF membranes in the bone defect. The outcome of the surgical treatment was successful in all patients, in a follow-up range from 12 to 36 months. In the cases presented, the macroscopic evaluation showed excellent and fast soft tissue healing, with no recurrence of bone exposure and no signs of infections. PRF membranes were also effective for postsurgical pain control. The use of PRF may represent a valuable adjunct in the surgical management of MRONJ.

Maxillary Sinus Augmentation for Dental Implant Rehabilitation of the Edentulous Ridge: A Comprehensive Overview of Systematic Reviews

OBJECTIVES

The objective of this systemic review was to perform a comprehensive overview of systematic reviews and meta-analyses of the maxillary sinus augmentation procedure for implant rehabilitation in humans. The following were evaluated in this overview: (1) anatomic variables affecting sinus augmentation, (2) histomorphometric analysis of the grafted sinus, (3) volumetric changes after sinus grafting, and (4) implant survival beyond 1 year.

MATERIAL AND METHODS

Electronic databases were searched for systematic reviews and meta-analyses of implant-related sinus augmentation published from 1976 to September 2015. The studies selected must identify itself as a systemic review or meta-analysis in the title or abstract and must pertain to sinus augmentation.

RESULTS

Thirty-three publications fulfilled the review criteria. The AMSTAR ratings for the 33 chosen reviews scored greater than 3 of 11, with 8 reviews scoring greater or equal to 8 of 11.

CONCLUSION

The outcome of this overview suggested that the following will increase the success of sinus augmentation and survival of implants placed in the grafted sinus: (1) the use of barrier membranes over the lateral window when using a lateral approach to graft the sinus, (2) the use of particulate autogenous bone with or without other substitute graft materials, (3) sinus augmentation without the use of grafting materials may be considered provided that the space between the sinus membrane and floor can be maintained, (4) the use of rough-surfaced implants, (5) simultaneous implant placement with residual bone height greater than 4 mm, and (6) the cessation of smoking.

Bioactive treatments in bone grafts for implant-based rehabilitation: Systematic review and meta-analysis

BACKGROUND

The use of bioactive proteins, such as rhBMP-2, may improve bone regeneration in oral and maxillofacial surgery.

PURPOSE

Analyze the effect of using bioactive proteins for bone regeneration in implant-based rehabilitation.

MATERIALS AND METHODS

Seven databases were screened. Only clinical trials that evaluated the use of heterologous sources of bioactive proteins for bone formation prior to implant-based rehabilitation were included. Statistical analyses were carried out using a random-effects model by comparing the standardized mean difference between groups for bone formation, and risk ratio for implant survival (P ≤ .05).

RESULTS

Seventeen studies were included in the qualitative analysis, and 16 in the meta-analysis. For sinus floor augmentation, bone grafts showed higher amounts of residual bone graft particles than bioactive treatments (P ≤ .05). While for alveolar ridge augmentation bioactive treatments showed a higher level of bone formation than control groups (P ≤ .05). At 3 years of follow-up, no statistically significant differences were observed for implant survival (P > .05).

CONCLUSIONS

Bioactive proteins may improve bone formation in alveolar ridge augmentation, and reduce residual bone grafts in sinus floor augmentation. Further studies are needed to evaluate the long-term effect of using bioactive treatments for implant-based rehabilitation.

Long-Term Implant Survival After 100 Maxillary Sinus Augmentations Using Plasma Rich in Growth Factors

PURPOSE

To identify determinants of long-term implant survival after sinus augmentation procedure (SAP) using a combination of plasma rich in growth factors (PRGF) and graft material.

MATERIALS AND METHODS

Patients were included in this retrospective study if they underwent SAP through a lateral wall approach using PRGF in combination with mainly xenograft, and received implants restored for at least 1 year. Sociodemographic, behavioral and implant characteristics (clinical factors, implant details, surgical details, prosthesis details, and complications) were analyzed.

RESULTS

Sixty-seven patients received 217 implants in 100 augmented sinuses. The mean follow-up was 7.2 years. Overall, 22 implants failed in 15 patients (90% cumulative implant survival). Multivariable models showed greater implant survival with implants placed with ≥5 mm of residual crestal bone height (RBH) compared with those placed with <3 mm of RBH. There was also an improvement in survival comparing implant lengths. In addition, immediate loading of implants significantly increased the risk of implant failure.

CONCLUSION

The use of PRGFs for maxillary sinus grafting may be an effective and safe treatment option for the rehabilitation of atrophic edentulous posterior maxillae. However, randomized clinical trials are needed to confirm these findings.

Efficacy of platelet concentrates in bone healing: A systematic review on animal studies - Part B: Large-size animal models

In the presence of large bone defects, delayed bone union, or nonunion and fractures, bone reconstruction may be necessary. Different strategies have been employed to enhance bone healing among which the use of autologous platelet concentrates (APCs). Due to the high content of platelets and platelet-derived bioactive molecules (e.g., growth factors, antimicrobial peptides), they are promising candidates to enhance bone healing. However, both preclinical and clinical studies produced contrasting results, mainly due to a high heterogeneity in study design, objectives, techniques adopted, and outcomes assessed. The aim of the present systematic review was to evaluate the efficacy of APCs in animal models of bone regeneration, considering the possible factors that might affect the outcome. An electronic search was performed on MEDLINE and Scopus databases. Comparative animal studies with a minimum follow up of 2 weeks, at least five subjects per group and using APCs for regeneration of bone defects were included. Articles underwent risk of bias assessment and quality evaluation. Fifty studies performed on six animal species (rat, rabbit, dog, sheep, goat, mini-pig) were included. The present part of the review considers studies performed on small ruminants, dogs, and mini-pigs (14 articles). The majority of the studies were considered at low risk of bias. In general, APCs' adjunct positively affected bone regeneration. Animal species, platelet and growth factors concentration, type of bone defect and of platelet concentrate used seemed to influence their efficacy in bone healing. However, sound conclusions were not drawn since too few studies for each large-size animal model were included. In addition, characterization of APCs' content was performed only in a few studies. Further studies with a standardized protocol including characterization of the final products will provide useful information for translating the results to clinical application of APCs in bone surgery.

Maxillary Sinus Floor Augmentation: a Review of Selected Treatment Modalities

Objectives

The objective of the present study is to present the current best evidence for enhancement of the vertical alveolar bone height and oral rehabilitation of the atrophic posterior maxilla with dental implants and propose some evidence-based treatment guidelines.

Material and Methods

A comprehensive review of the English literature including MEDLINE (PubMed), Embase and Cochrane Library search was conducted assessing the final implant treatment outcome after oral rehabilitation of the atrophic posterior maxilla with dental implants. No year of publication restriction was applied. The clinical, radiological and histomorphometric outcome as well as complications are presented after maxillary sinus floor augmentation applying the lateral window technique with a graft material, maxillary sinus membrane elevation without a graft material and osteotome-mediated sinus floor elevation with or without the use of a graft material.

Results

High implant survival rate and new bone formation was reported with the three treatment modalities. Perforation of the Schneiderian membrane was the most common complication, but the final implant treatment outcome was not influenced by a Schneiderian membrane perforation.

Conclusions

The different surgical techniques for enhancement of the vertical alveolar bone height in the posterior part of the maxilla revealed high implant survival with a low incidence of complications. However, the indication for the various surgical techniques is not strictly equivalent and the treatment choice should be based on a careful evaluation of the individual case. Moreover, further high evidence-based and well reported long-term studies are needed before one treatment modality might be considered superior to another.

Maxillary Sinus Floor Elevation Using Platelet-Rich Plasma Combined With Either Biphasic Calcium Phosphate or Deproteinized Bovine Bone

PURPOSE

Maxillary sinus floor elevation procedure has the objective of augmenting available bone in atrophic posterior maxilla to allow dental implants placement. The main aim of this prospective study was to evaluate clinically and histomorphometrically the performance of biphasic calcium phosphate (BCP) used in conjunction with platelet-rich plasma (PRP) compared with demineralized bovine bone matrix (DBBM) and PRP in sinus floor elevation surgery.

MATERIALS AND METHODS

Patients candidate to sinus floor elevation were treated using either BCP and PRP or DBBM and PRP. Biopsies were retrieved using trephine bur during implant placement surgery 6 months after grafting. Clinical success of implants was evaluated 1 year after prosthesis delivery. Histomorphometric analysis was performed assessing the relative volume of newly formed bone.

RESULTS

A total of 20 patients were recruited, and 20 sinus augmentation procedures were performed, 10 for each group. A total of 42 implants were placed. One year after prosthetic loading a 100% implant survival rate was reported in both groups. Histomorphometric analysis revealed that the mean amount of new bone formation was 18.6 ± 3.3% in BCP group and it was 21.9 ± 4.9% in DBBM group, without statistically significant difference. In BCP group a greater amount of collagen type I was found with respect to DBBM group.

CONCLUSIONS

Both grafting materials led to an excellent performance regarding implant survival rate after 1 year follow-up, without any significant adverse sequelae. A similar capability of inducing new bone formation was observed in both groups, even though the higher quantity of collagen type I in BCP group may suggest a greater potential for bone formation over time as compared with DBBM.

Immediate post-extraction implants with or without pure platelet-rich plasma: a 5-year follow-up study

PURPOSE

The purpose of this study was comparison of clinical and radiographic outcomes of immediate post-extraction implants with or without the use of pure platelet-rich plasma (P-PRP) in the short- and medium-term follow-up.

METHODS

A retrospective analysis was performed to assess soft tissue healing, implant and prosthesis survival, marginal bone level changes and biological complications.

RESULTS

A total of 109 partially edentulous patients with 126 implants were included in this analysis. At 4-5 years after loading, cumulative survival rate in test group was 97.4% and in control group was 97.8%, with no significant differences. After 5 years of function, marginal bone loss (MBL) in test group was 0.8 ± 0.35 and 1.02 ± 0.27 mm for immediate and delayed loading, respectively, and in control group was 0.6 ± 0.16 and 0.8 ± 0.89 mm for immediate and delayed loading, respectively. No significant differences in MBL were observed intragroups and intergroups at any time point considered. Soft tissue healing score was significantly higher in test group compared to the control at 3 and 7 days after surgery, with significant differences.

CONCLUSIONS

P-PRP implant group showed a better soft tissue management and wound healing in the first 7 days after surgery compared to non-P-PRP implant group. In the medium-term follow-up, comparable clinical and radiographic outcomes were noticed between two groups.

Is Alveolar Ridge Split a Risk Factor for Implant Survival?

PURPOSE

There is a paucity of studies that have assessed the long-term outcomes of the alveolar ridge split (ARS). This study evaluated the intraoperative and postoperative complications and assessed the placed dental implant and prosthesis.

MATERIALS AND METHODS

A retrospective study of the ARS was conducted in a single private dental clinic. The predictor variable was the ARS technique (1 stage vs 2 stages). The primary outcome was the dental implant survival rate. Secondary outcomes were intraoperative complications, marginal bone loss, prosthetic complications, and prosthesis success rate. Descriptive analysis was performed for patients' demographic data, implant details, and prosthetic complications. The Kaplan-Meier method was used to assess implant survival rate and prosthesis success rate.

RESULTS

Twenty patients (mean age, 55 ± 6 yr) had a mean follow-up time of 5 years. Delayed implant placement was performed when the residual alveolar bone width was narrower than 3 mm. No intraoperative or postoperative complications were reported. The survival rate of the 31 implants was 100% and the prosthesis success rate was 96.8%.

CONCLUSIONS

The ARS is an effective technique for horizontal bone augmentation in the mandible. Delayed dental implant placement when the alveolar bone width is narrower than 3 mm could minimize the risk of buccal wall fracture.

Long-term Evaluation of Peri-implant Bone Level after Reconstruction of Severely Atrophic Edentulous Maxilla via Vertical and Horizontal Guided Bone Regeneration in Combination with Sinus Augmentation: A Case Series with 1 to 15 Years of Loading

BACKGROUND

To the best of the authors' knowledge, there is very limited clinical data on the outcomes of simultaneous guided bone regeneration (GBR) for horizontal and/or vertical bone gain for the reconstruction of severely atrophic edentulous maxilla. Therefore, the purpose of the clinical series presented herein was to clinically evaluate long-term horizontal and vertical bone gain, as well as implant survival rate after reconstruction of severely atrophic edentulous maxillary ridges.

MATERIAL AND METHODS

Sixteen patients (mean age: 64.6 ± 14.6 years of age) were consecutively treated for vertical and/or horizontal bone augmentation via GBR in combination with bilateral sinus augmentation utilizing a mixture of autologous and anorganic bovine bone. Implant survival, bone gain, intraoperative/postoperative complications and peri-implant bone loss were calculated up to the last follow-up exam.

RESULTS

Overall, 122 dental implants were placed into augmented sites and have been followed from 12 to 180 months (mean: 76.5 months). Implant survival was 100% (satisfactory survival rate of 97.5%). Mean bone gain was 5.6 mm (max: 9 mm; min: 3 mm) While vertical bone gain was 5.1 ± 1.8 mm; horizontal bone gain was 7.0 ± 1.5 mm. No intraoperative/postoperative complications were noted. Mean peri-implant bone loss values were consistent within the standards for implant success (1.4 ± 1.0 mm). At patient-level, only one patient who had three implants presented with severe peri-implant bone loss.

CONCLUSION

Complete reconstruction of an atrophied maxilla can be successfully achieved by means of guided bone regeneration for horizontal and/or vertical bone gain including bilateral sinus augmentation using a mixture of anorganic bovine bone and autologous bone.

A Randomized Case-Series Study Comparing the Stability of Implant with Two Different Surfaces Placed in Fresh Extraction Sockets and Immediately Loaded

Background. Hydrophilic and moderately rough implant surfaces have been proposed to enhance the osseointegration response. Aim. The aim of this study was to compare early changes of stability for two implants with identical macrodesign but with different surface topographies. Materials and Methods. In 11 patients, a total of 22 implants (11 bimodal (minimally rough, control) and 11 proactive (moderately rough and hydrophilic, test), Neoss Ltd., Harrogate, UK) were immediately placed into fresh extraction sockets and immediately loaded. The peak insertion torque (IT) was measured in Ncm at placement. Resonance Frequency Analysis (RFA) measurements were made at baseline and 2, 4, 6, and 12 weeks after surgery. Results. The two implant types showed similar IT and RFA values at placement (NS). A dip of RFA values after 2 weeks followed by an increase was observed, where the test implant showed a less pronounced decrease and a more rapid recovery than the control implant. The test implants were significantly more stable than the control ones after 12 weeks. Conclusions. The results from the present study indicated that the hydrophilic and rougher test implant was more resistant to immediate loading and showed a significantly higher stability than the smoother control implant after 12 weeks.

Does Freeze-Thawing Influence the Effects of Platelet Concentrates? An In Vitro Study on Human Adipose-Derived Stem Cells

Human adipose-derived stem cells (hASCs) have been proposed as a possible therapy for tissue regeneration in aesthetic, plastic, and reconstructive surgery. Today, platelet concentrates are used in a wide range of disciplines, but their storage has become a controversial aspect. The purpose of this in vitro study was to evaluate the effect of plasma rich in growth factors (PRGF), after a freeze-thawing cycle, on the proliferation and biological activity of progenitor cells involved in soft tissue healing. Different formulations of activated PRGF were added to hASCs cultured in serum-free medium. Cell proliferation was assessed by MTT test and cell count up to 7 and 12-day incubation. Osteo-differentiation ability of hASCs was also tested after 7 and 14-day incubation by alkaline phosphatase assay. The effects of 4 PRGF preparations (fresh/frozen and with/without platelets) were compared with corresponding formulations of plasma poor in growth factors and with standard medium. hASCs cultured in the presence of platelet concentrates increased proliferation rate with respect to cells grown in standard medium without significant differences among all the tested plasma formulations on cell viability up to 12 days of culture. PRGF activity is preserved after cryopreservation and platelet-rich preparations promoted osteo-differentiation of hASCs at day 7. In conclusion, PRGF supports the proliferation and the differentiation of progenitor cells in vitro also when applied after cryopreservation. Platelet concentrates, either alone or in combination with mesenchymal stem cells, might be a valuable tool in the field of tissue regeneration.

Bone Augmentation in Rabbit Tibia Using Microfixed Cobalt-Chromium Membranes with Whole Blood and Platelet-Rich Plasma

Background: Bone augmentation is a subject of intensive investigation in regenerative bone medicine and constitutes a clinical situation in which autogenous bone grafts or synthetic materials are used to aid new bone formation. Method: Based on a non-critical defect, Co-Cr barrier membranes were placed on six adult Fauve de Bourgogne rabbits, divided into two groups: whole blood and PRP. Three densitometric controls were performed during the experiment. The animals were euthanized at 30, 45, 60, and 110 days. The presence of newly formed bone was observed. Samples for histological studies were taken from the augmentation center. Results: External and internal bone tissue augmentation was observed in almost all cases. Significant differences between PRP- and whole blood–stimulated bone augmentation were not observed. At 60 days, bones with PRP presented higher angiogenesis, which may indicate more proliferation and cellular activity. Conclusion: PRP activates the bone regeneration process under optimized conditions by stimulation of osteoblast proliferation after six weeks, when a significant difference in cellular activity was observed. Membranes could stimulate bone augmentation at the site of placement and in the surrounding areas.

Platelet preparations in dentistry: How? Why? Where? When?

The aim of this article is to review the outcomes of platelet preparations in dentistry. A structured electronic search discovered 348 articles, which described the use of autologous platelet concentrates with a relevance to clinical dentistry. Among these articles, 220 articles investigated platelet rich plasma, 99 investigated platelet rich fibrin, 22 investigated plasma rich in growth factors and 7 investigated the use of concentrated growth factors. Several studies reported beneficial treament outcomes in terms of enhanced bone and soft tissue regeneration.

Vertical bone regeneration with deproteinised bovine bone mineral or biphasic calcium phosphate in the rabbit calvarium: effect of autologous platelet lysate

Although bone substitutes associated with platelet concentrates are widely used to vertically reconstruct alveolar ridges, their respective and specific contribution remain controversial. The aim of this study was to evaluate the benefit of using either biphasic calcium phosphate (BCP) or demineralised bovine bone mineral (DBBM) alone or with autologous platelet lysate (APL) in vertical bone regeneration. The study involved fourteen New Zealand rabbits. Autologous APL was prepared by freeze-thawing from a platelet suspension (10(9) platelets/ml). Four CP titanium (cpTi) cylinders were fixed to each calvarium; one cylinder was empty, one was filled with APL alone and the others were filled either with BCP or BCP + APL or DBBM or DBBM + APL. New bone formation and biomaterial resorption were evaluated using non-demineralised histology and histomorphometry. After 6 weeks, new bone formation was observed in all cylinders. The newly formed bone in the cylinders filled with APL alone, DBBM and BCP was significantly increased by (0.6-, 2.5- and 3.3-fold, respectively) (P < 0.0001) compared to results obtained with the empty cylinders. Vertical bone height in the cylinders filled with BCP was greater to that observed with DBBM. The residual material in the cylinders filled with BCP was significantly (P < 0.0001) lower (0.35-fold) than that with DBBM. Both newly formed bone and residual material in the cylinders filled with BCP + APL or DBBM + APL were similar to those filled with either BCP or DBBM, respectively. This study provided evidence that APL alone, as well as DBBM and BCP, have a beneficial effect on vertical bone formation and remodelling. APL associated with either DBBM or BCP did not provide additional benefits.

Autologous platelet concentrates for bisphosphonate-related osteonecrosis of the jaw treatment and prevention. A systematic review of the literature

PURPOSE

Bisphosphonate related osteonecrosis of the jaw (BRONJ) is an adverse drug reaction consisting of progressive bone destruction in the maxillofacial region of patients under current or previous treatment with a bisphosphonate. Autologous platelet concentrates (APC) demonstrated to enhance bone and soft tissue healing in oral surgery procedures. The present systematic review aimed at evaluating if APC may improve treatment and prevention of BRONJ in patients under bisphosphonate therapy.

METHODS

MEDLINE, Scopus and Cochrane databases were searched using terms like bisphosphonates, osteonecrosis, BRONJ, platelet concentrate, PRP, PRF, PRGF. No language, publication date and study design limitation was set. A hand search of the bibliographies of identified articles was also performed. The primary outcome was recurrence/onset of BRONJ after oral surgery procedures.

RESULTS

Eighteen studies were included, reporting on 362 patients undergoing oral surgery in combination with APC. The adjunct of APC in BRONJ treatment significantly reduced osteonecrosis recurrence with respect to control. APC was associated with a lower BRONJ incidence after tooth extraction, though not significant. Heterogeneity was found regarding bisphosphonate type, clinical indication, treatment duration, triggering factors, study design, follow-up duration, type of APC, outcomes adopted to evaluate treatment success.

CONCLUSION

Though the results of this review must be cautiously interpreted, due to the low evidence level of the studies included, and the limited sample size, they are suggestive of possible benefits of APC when associated with surgical procedures for treatment or prevention of BRONJ. To confirm such indication, prospective comparative studies with a large sample size are urgently needed.

The topical administration of bisphosphonates in implant surgery: a randomized split-mouth prospective study with a follow-up up to 5 years

OBJECTIVE

To evaluate the efficacy of the topical administration of bisphosphonates in implant therapy.

MATERIALS AND METHODS

Thirty-nine consecutive patients were selected for a split-mouth study. Inclusion criteria were: presence of a bilateral or total edentulism, ability to tolerate conventional implant procedures, older than 18 years. Ten patients were smokers. Ten patients were fully edentulous in both maxilla and mandible, 12 patients had fully edentulous maxilla or mandible, and 17 were bilaterally partially edentulous (9 in the mandible and 8 in the maxilla). A one-stage procedure was adopted in all cases. The prosthetic phase started 10 weeks after implant insertion. Each patient received implants on the control side and the test side, with insertion performed in the conventional way on the control side; on the test side, a 3% clodronate solution mixed with a surfactant (Tween-20) at a 1:3 ratio was topically administered both at the implant surface and at the implant site.

RESULTS

One hundred fifty-five implants were inserted. The test and control groups included 75 and 80 implants, respectively. The implant insertion torque was no less than 30 Ncm. A total of 7 implants failed in the control group (6 before loading and one after 12 months of loading). No failure occurred on the test side. By the 5-year follow-up, no further implant failure had been recorded. Overall, implant survival rates at 5 years for the test and control groups were, respectively, 100% and 91.3%, the difference being significant (p < .01). Mean marginal bone loss was 0.85 ± 0.71 mm in the test group and 1.12 ± 0.85 mm in the control group after 1 year of loading and stable thereafter. The difference was not significant.

CONCLUSIONS

The topical administration of bisphosphonates may positively affect implant survival in the preloading and postloading phases in partially and fully edentulous patients. However, a larger study population is needed to verify these promising clinical results.

Clinical applications of cell-based approaches in alveolar bone augmentation: a systematic review

BACKGROUND

Cell-based approaches, utilizing adult mesenchymal stem cells (MSCs), are reported to overcome the limitations of conventional bone augmentation procedures.

PURPOSE

The study aims to systematically review the available evidence on the characteristics and clinical effectiveness of cell-based ridge augmentation, socket preservation, and sinus-floor augmentation, compared to current evidence-based methods in human adult patients.

MATERIALS AND METHODS

MEDLINE, EMBASE, and CENTRAL databases were searched for related literature. Both observational and experimental studies reporting outcomes of "tissue engineered" or "cell-based" augmentation in ≥5 adult patients alone, or in comparison with non-cell-based (conventional) augmentation methods, were eligible for inclusion. Primary outcome was histomorphometric analysis of new bone formation. Effectiveness of cell-based augmentation was evaluated based on outcomes of controlled studies.

RESULTS

Twenty-seven eligible studies were identified. Of these, 15 included a control group (8 randomized controlled trials [RCTs]), and were judged to be at a moderate-to-high risk of bias. Most studies reported the combined use of cultured autologous MSCs with an osteoconductive bone substitute (BS) scaffold. Iliac bone marrow and mandibular periosteum were frequently reported sources of MSCs. In vitro culture of MSCs took between 12 days and 1.5 months. A range of autogenous, allogeneic, xenogeneic, and alloplastic scaffolds was identified. Bovine bone mineral scaffold was frequently reported with favorable outcomes, while polylactic-polyglycolic acid copolymer (PLGA) scaffold resulted in graft failure in three studies. The combination of MSCs and BS resulted in outcomes similar to autogenous bone (AB) and BS. Three RCTs and one controlled trial reported significantly greater bone formation in cell-based than conventionally grafted sites after 3 to 8 months.

CONCLUSIONS

Based on limited controlled evidence at a moderate-to-high risk of bias, cell-based approaches are comparable, if not superior, to current evidence-based bone grafting methods, with a significant advantage of avoiding AB harvesting. Future clinical trials should additionally evaluate patient-based outcomes and the time-/cost-effectiveness of these approaches.

Impact of the use of plasma rich in growth factors (PRGF) on the quality of life of patients treated with endodontic surgery when a perforation of sinus membrane occurred. A comparative study

INTRODUCTION

The aim of this retrospective investigation was to evaluate the postoperative quality of life after endodontic surgery in maxillary molars when a sinus membrane perforation occurred and platelet concentrates were used.

MATERIALS AND METHODS

Included patients were treated by microsurgical endodontic treatment in molar and premolar maxillary regions between 2007 and 2010. Patients who fulfilled the inclusion criteria were screened. Data from the quality of life questionnaire were analyzed. The use of plasma rich in growth factors (PRGF) (test group) was compared with a control group when a Schneiderian membrane perforation occurred during endodontic surgery performed with a modern technique in maxillary molars and premolars.

RESULTS

A total of 20 patients (12 in the control group and eight in the test group) fulfilled the inclusion criteria. No differences were evaluated at baseline for clinical parameters. Significantly improved patients' quality of life was observed in the test group considering symptoms as swelling, bad breath or taste, and pain. Functional activities were less impaired in the test group and swelling was significantly higher in the control group. In the test group, pain was significantly lower than the control group during the first 6 days after surgery and also, the consumption of painkillers was lower for patients belonging to the test group even if it was not statistically significant.

DISCUSSION

In general, a small sinus membrane perforation (less than 6 mm) during endodontic surgery did not cause severe complications. The use of platelet concentrates could be effective in reducing the impact on patients' quality of life, decreasing pain and surgery side effects as well as swelling.

Effect of platelet concentrate on quality of life after periradicular surgery: a randomized clinical study

INTRODUCTION

Control of postoperative discomfort might enhance the patient's quality of life and treatment acceptance. The aim of the present randomized single-blind study was to evaluate whether the use of platelet concentrate during endodontic surgery might have a favorable impact on pain and other factors related to patient's quality of life during the first week after surgery.

METHODS

Eighteen patients with periapical lesion were treated with modern endodontic surgical procedure (control group). In another 18 patients, in adjunct to surgical procedure, platelet concentrate was applied on the root end in liquid form, within the bone defect in clot form, and over the suture in liquid form (test group). All patients completed a questionnaire for evaluation of main symptoms and daily activities during the first week after surgery. The outcomes of the questionnaires of the 2 groups were statistically compared.

RESULTS

The test group showed significantly less pain and swelling, fewer analgesics taken, and improved functional activities as compared with the control group.

CONCLUSIONS

The adjunct of platelet concentrate to the endodontic surgical procedure produced significant beneficial effect to patients' quality of life during the early postoperative stage.