A Comparative Study of Bilateral Sinus Lifts Performed with Platelet-Rich Plasma Alone Versus Alloplastic Graft Material Reconstituted with Blood

Emerging roles of platelet concentrates and platelet-derived extracellular vesicles in regenerative periodontology and implant dentistry

Platelet concentrates (PCs) are easily obtained from autogenous whole blood after centrifugation and have evolved through three generations of development to include platelet-rich plasma, platelet-rich fibrin, and concentrated growth factor. Currently, PCs are widely used for sinus floor elevation, alveolar ridge preservation, periodontal bone defects, guided bone regeneration, and treatment of gingival recession. More recently, PCs have been leveraged for tissue regeneration to promote oral soft and hard tissue regeneration in implant dentistry and regenerative periodontology. PCs are ideal for this purpose because they have a high concentration of platelets, growth factors, and cytokines. Platelets have been shown to release extracellular vesicles (P-EVs), which are thought to be essential for PC-induced tissue regeneration. This study reviewed the clinical application of PCs and P-EVs for implant surgery and periodontal tissue regeneration.

The Application of Beta-Tricalcium Phosphate in Implant Dentistry: A Systematic Evaluation of Clinical Studies

The demand for synthetic graft materials in implant dentistry is rising. This systematic review aims to evaluate the survival rate of dental implants placed simultaneously with bone regeneration procedures using the material β-tricalcium phosphate, one of the most promising synthetic graft materials. The electronic search was conducted in PubMed, Scielo, and the Cochrane Central Register of Controlled Trials. Five randomized clinical trials, one non-randomized controlled clinical trial and four observational studies without control group were include. Implant survival rate and other clinical, radiographic, and histological parameters did not differ from those of implants placed simultaneously with another type of graft material, or placed in blood clots or natural alveolar ridges. Based on the available literature, β-tricalcium phosphate seems to be a promising graft material in implant dentistry. Nevertheless, more randomized clinical trials, with long follow-up periods, preoperative and postoperative CBCT, and histological analysis, are necessary to assess its long-term behavior.

Minimally Invasive Transcrestal Sinus Floor Elevation Procedure in Severely Atrophic Ridge: A Case Report

Typically, the greater the atrophy of the process, the more extensive and invasive the sinus floor elevation procedure is. This case of a 39-year-old man demonstrates a minimally invasive hydrostatic sinus lift from 1.7-mm height process in the site of lost tooth No. 16. Using a small flap, safe drills for a crestal approach diameter of 2.8 mm, 2 mL of saline solution under pressure of a syringe plunger, and 1 g of particulated bovine xenograft, a 14-mm height and 12-mm width sinus floor elevation was obtained. The implant was placed with a torque of 30 Ncm, and a healing cap was attached. Despite the very difficult conditions, the presented method not only resulted in a very good therapeutic effect but also reduced the number of procedures and time necessary for complete rehabilitation of the patient. The total treatment time to the final crown delivery was 6 months.

Sinus membrane elevation and implant placement

Sinus Schneiderian membrane elevation surgery is widely performed for dental implant placement in the maxillary posterior region. With regard to sinus elevation surgery, various complications can occur and lead to implant failure. For successful implants in the maxillary posterior region, the clinician must be well acquainted with sinus anatomy and pathology, a variety of bone graft materials, the principles of sinus elevation surgery, and prevention and management of complications.

Maxillary Sinus Membrane Elevation With Simultaneous Installation of Implants Without the Use of a Graft Material: A Systematic Review

OBJECTIVE

To compare implant treatment outcome after maxillary sinus membrane elevation with simultaneous installation of implants with or without the use of graft material applying the lateral window technique.

MATERIALS AND METHODS

MEDLINE/PubMed, Cochrane Library, and Embase search in combination with a hand-search of relevant journals was conducted from January 1, 2004 to January 1, 2016.

RESULTS

Thirteen studies fulfilled the inclusion criteria. Survival of suprastructures has not been compared within the same study. Short-term implant survival without graft material varied between 96% and 100% compared to 100% for autogenous bone or bone substitutes. No significant difference in bone gain was reported without graft material compared to autogenous bone. The density of newly formed bone increased significantly during the observation period. Bone density was significantly higher in sinuses augmented with blood clot compared to bone substitute, whereas no significant difference was found when compared to autogenous bone. Noncomparative studies demonstrated high long-term implant survival and new bone formation after sinus membrane elevation without graft material.

CONCLUSIONS

Sinus membrane elevation without the use of a graft material seems to enhance new bone formation with high implant survival, but long-term comparative studies are missing.

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.

Effects of platelet-rich plasma in association with bone grafts in maxillary sinus augmentation: a systematic review and meta-analysis

This systematic review evaluated the effect on bone formation and implant survival of combining platelet-rich plasma (PRP) with bone grafts in maxillary augmentation. A comprehensive review of articles listed in the PubMed/MEDLINE, Embase, and Cochrane Library databases covering the period January 2000 to January 2015 was performed. The meta-analysis was based on bone formation for which the mean difference (MD, in millimetres) was calculated. Implant survival was assessed as a dichotomous outcome and evaluated using the risk ratio (RR) with 95% confidence interval (CI). The search identified 3303 references. After inclusion and exclusion criteria were applied, 17 studies were selected for qualitative analysis and 13 for quantitative analysis. A total of 369 patients (mean age 51.67 years) and 621 maxillary sinus augmentations were evaluated. After the data analysis, additional analyses were performed of the implant stability quotient, marginal bone loss, and alveolar bone height measured by MD. The results showed no significant difference in implant stability (P=0.32, MD 1.00, 95% CI -0.98 to 2.98), marginal bone loss (P=0.31, MD 0.06, 95% CI -0.05 to 0.16), alveolar bone height (P=0.10, MD -0.72, 95% CI -1.59 to 0.14), implant survival (P=0.22, RR 1.95, 95% CI 0.67-5.69), or bone formation (P=0.81, MD -0.63, 95% CI -5.91 to 4.65). In conclusion, the meta-analysis indicates no influence of PRP with bone graft on bone formation and implant survival in maxillary sinus augmentation.

Measurements of Implant Stability Following Sinus Lift: A Pilot Clinical Study

AIM

The aim of this study was to evaluate the implant stability of Bredent Sky Blue implants of different diameters following one stage sinus lift procedure.

MATERIAL AND METHODS

This study included 9 male patients with an existing indication for unilateral or bilateral sinus lift procedure. As grafting materials, combination of allograft material MinerOss® cortical & cancellous and Ossceram nano were used.

RESULTS

All implants were considered successful and ISQ levels were measured by Osstell ISQ device. The ISQ values were from 68 to 84. The mean values of stability of Bredent Sky Blue implants of different diameters following one stage sinus lift procedure were 77.73 ± 2.93 (MD) and 77.98 ± 2.72 (VO).

Comparative study of alveolar bone height and implant survival rate between autogenous bone mixed with platelet rich plasma versus venous blood for maxillary sinus lift augmentation procedure

AIM AND OBJECTIVES

The aim of this study was to evaluate changes in alveolar bone height by means of radiographic examination and Straumann implant survival rate following maxillary sinus lift augmentation using autogenous bone in combination with platelet rich plasma (PRP) versus venous blood (VB).

METHODS

Fifty patients requiring sinus lift augmentation procedure included in the study were divided into two groups (n = 25). During the procedure the sub antral sinus cavity was augmented using autogenous bone taken from mandibular ramus area and mixed with PRP in one group and autogenous bone mixed with VB in the other group. Orthopantomograms were taken preoperatively, immediate, at 6 months and 1 year postoperatively. Height of alveolar bone at the site of sinus augmentation was measured on the radiographs. One hundred and twenty-one Straumann dental implants were placed after healing period.

RESULTS

Age of the patients in the study groups ranged from 36 to 69 years. Differences in mean values of bone height measurements recorded in the PRP series revealed significant differences among the three subgroups (P = 0.001). Significant differences were noted between immediate postop and 6 month (P < 0.01), immediate postop and year (P < 0.01). In the VB series also significant differences were revealed among the three subgroups (P = 0.0280). Significant differences were noted between immediate postop and 6 month (P < 0.05). Comparison of results of subgroups of the two series at the three intervals revealed significant differences at 'immediate postop' values (P = 0.0002) and 'sixmon' values (P = 0.0435). Differences between 'year' values were not significant. Two implants were lost in PRP group.

CONCLUSION

The results of this limited study reveals that both groups recorded a good increase in the alveolar bone height after sinus augmentation and showed no significant differences between these groups when compared to each other at 1 year postoperatively. When both sub groups compared with immediate postop to year, PRP group showed significant difference and blood group showed no significant difference.

Effect of maxillary sinus floor augmentation without bone grafts

Objective:

The objective of the present review was to determine the effectiveness of maxillary sinus floor augmentation without bone grafts using lateral window technique.

Materials and Methods:

PubMed and Cochrane databases were searched for relevant articles. We also included articles by hand search until June 2012. The analysis included both human and animal studies which satisfied the following criteria: Minimum of 6 months follow-up, no use of bone grafts, and lateral window approach to the sinus.

Results:

We included 22 articles in the review. A descriptive analysis of the constructed evidence tables indicated that there is evidence of predictable a mount of bone formation in the maxillary sinus augmentation without the use of bone grafts.

Conclusion:

Within the limits of the articles and data available, maxillary sinus augmentation without bone graft might be considered effective inpredictable bone formation.

Interventions for replacing missing teeth: augmentation procedures of the maxillary sinus

BACKGROUND

Insufficient bone volume is a common problem encountered in the rehabilitation of the edentulous posterior maxillae with implant-supported prostheses. Bone volume is limited by the presence of the maxillary sinus together with loss of alveolar bone height. Sinus lift procedures increase bone volume by augmenting the sinus cavity with autogenous bone or commercially available biomaterials, or both. This is an update of a Cochrane review first published in 2010.

OBJECTIVES

To assess the beneficial or harmful effects of bone augmentation compared to no augmentation when undertaking a sinus lift procedure. Secondly, to compare the benefits and harms of different maxillary sinus lift techniques for dental implant rehabilitation.

SEARCH METHODS

We searched the Cochrane Oral Health Group's Trials Register (to 17 January 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 12), MEDLINE via OVID (1946 to 17 January 2014) and EMBASE via OVID (1980 to 17 January 2014). There were no language or date restrictions on the searches of the electronic databases.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of different techniques and materials for augmenting the maxillary sinus for rehabilitation with dental implants that report the outcome of implant success or failure at least to four months after initial loading.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the risk of bias of the trials, and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed using fixed-effect models as there were either less than four studies or we used Peto odds ratios (ORs) for dichotomous data when there were zero cells in either the treatment or control or both arms and the number of trials was small. The statistical unit of the analysis was the patient.

MAIN RESULTS

Eighteen RCTs out of 64 potentially eligible study reports met the inclusion criteria. They compared undertaking a sinus lift with not doing so, and the use of different sinus lift techniques. There were 650 patients providing data for the outcomes evaluated. Five studies were assessed as low risk of bias, 11 were assessed as high risk of bias, and in two the risk was unclear. Sinus lift versus no sinus lift Four trials of moderate quality (three trials at low and one at high risk of bias) with 102 participants evaluated short implants (5 to 8.5 mm long) as an alternative to sinus lift in bone with residual height between 4 and 9 mm. One year after loading there was insufficient evidence to claim differences between the two procedures for prosthesis failure (OR (Peto) 0.37, 95% confidence interval (CI) 0.05 to 2.68; three trials) or implant failure (OR (Peto) 0.44, 95% CI 0.10 to 1.99; four trials). There was however an increase in complications at treated sites when undertaking the sinus lift (OR (Peto) 4.77, 95% CI 1.79 to 12.71, P value = 0.002; four trials). Different sinus lift techniques Fourteen trials with 548 participants compared different sinus lift techniques. Only three comparisons included more than one trial (two trials for each). These were bone graft versus no bone graft, autogenous bone versus bone substitute, bone graft with or without platelet-rich plasma (PRP). There was insufficient evidence to claim a benefit for any of these techniques for the primary outcomes of prosthesis and implant failure. For the other reported outcomes, in a single study at high risk of bias, only bone gain was greater for the bone graft site than the site without a graft six months after augmentation, however this was not significant at 18 or 30 months.The other comparisons with single studies were rotary versus piezosurgery to open a lateral sinus window, two different bone substitutes, use or not of a membrane to seal the lateral window, one- versus two-stage lateral sinus lift, two-stage granular bone versus one-stage autogenous bone blocks, and crestal versus lateral sinus lift; two trials compared three different crestal sinus lifting techniques: rotatory versus hand malleting (patients preferred rotatory instruments over hand malleting) and hand versus electric malleting. There was no evidence of a benefit for any sinus lift procedure compared to any other for the primary outcomes prosthesis or implant failure.

AUTHORS' CONCLUSIONS

There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 8.5 mm) in reducing prosthesis or implant failure up to one year after loading. However, there are more complications at sites treated with sinus lift procedures. Many trials compared different sinus lift procedures and none of these indicated that one procedure reduced prosthetic or implant failures when compared to the other. Based on low quality evidence, patients may prefer rotary instruments over hand malleting for crestal sinus lift.

Osteoconduction and Bioresorption of Bone Allograft versus Anorganic Bovine Bone Xenograft: A Histomorphometric Study in Humans

This clinical study evaluated the tissue repair process using different bone grafts. Nine dental patients with indication for posterior implantodontic treatment were submitted to maxillary sinus lifting procedures associated to grafting. After 6 months, bone biopsies (6 sites with allogenous bone grafting and 13 sites with bovine xenogenous bone grafting/OsseusTM) were removed and processed for histopathological and histomorphometric analyses (ANOVA and Tukey's test). Both groups had tissue biocompatibility without significant inflammatory response, only punctual presence of multinucleated giant cells in xenograft group. Osteoconductive potential was evidenced by new bone tissue surrounding and in direct contact with the granules of both grafts. Volume density of connective tissue was similar between groups, although there were significant differences in allograft group in comparison to xenograft as the presence of new bone formation (48.50%±13.93 versus 29.83±9.56, respectively, p<0.05) and remnant biomaterial (1.57±2.39 versus 22.23±12.41, respectively, p<0.001), suggesting a greater osteoconductivity and faster bioresorption in the allograft group. These results demonstrate that allogenous bone and OsseusTM can be satisfactorily used as grafts in minor oral surgeries for bone augmentation in humans.

Direct vs. indirect sinus lift procedure: A comparison

BACKGROUND

There are different techniques for the sinus augmentation; the factors that contribute to the survival rate of sinus augmentation and dental implant placement are still the subject of discussion. So we compare the two different ways of sinus floor elevation: a) Lateral antrostomy as a one or two step procedure as direct method. b) Osteotome technique with a crestal approach as indirect method.

MATERIALS AND METHODS

A total of twenty partially edentulous patients in maxillary posterior region who opted for implant retained prosthesis but had a low sinus and deficient alveolar ridge within the age group of 20-55 years were taken up, 25 implants were placed in combination with bone grafting material for sinus augmentation. The final bone height was measured from Orthopantomogram. Post-operative Clinical Evaluation was based on pain, gingival inflammation status, stability, swelling and bone height. Statistical analysis was done by using Statistical Package for Social Sciences (version 15.0) (SPSS Inc., Chicago, IL, USA).

RESULTS

The gain in bone height was significantly greater in direct procedure through lateral antrostomy (mean 8.5 mm) than in indirect method through crestal approach by osteotome technique (mean 4.4 mm).

CONCLUSIONS

Osteotome technique can be recommended when more than 6 mm of residual bone height is present and an increase of 3-4 mm is expected. In case of more advanced resorption direct method through lateral antrostomy has to be performed. Both sinus elevation techniques did not seem to affect the implant success rate.

Evaluation of the effects of the use of platelet-rich plasma (PRP) on alveolar bone repair following extraction of impacted third molars: prospective study

Platelet-rich plasma (PRP) is rich in growth factors, target-specific polypeptides that play a role in cell proliferation and differentiation and can thus encourage wound repair. This study sought to assess the effects of PRP on new bone formation in a sample of 25 patients with clinical indications for extraction of all four impacted third molars with similar orientation, depth, and root morphology. Immediately after extraction, sockets on one side received PRP, whereas those on the other side (control) did not. Patients underwent 6 months of clinical and radiographic follow-up. Periapical radiographs were scanned and bone repair was assessed by image histogram analysis. The radiographic densities of the extraction sockets were compared to the densities of the distal surfaces of the adjacent teeth, with the difference between both serving to distinguish the PRP and control sides. Results showed that healing of PRP-treated sockets was significantly different from that of control sockets at 1-, 3-, and 6-month follow-up, in mandibular and maxillary sockets alike. The results of this sample suggest that PRP provides a safe and effective means of speeding alveolar bone repair.

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.

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

PURPOSE

The aim of the present study was to systematically evaluate the effect of autogenous platelet concentrates on the clinical and histomorphometric outcomes of maxillary sinus augmentation.

MATERIALS AND METHODS

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched using a combination of specific search terms. Furthermore, a hand searching of the relevant journals and of the bibliographies of reviews was performed. Prospective comparative clinical studies were included. Implant survival and histomorphometric outcomes were evaluated.

RESULTS

Twelve studies were included. Four hundred forty-five sinus floor augmentation procedures were considered. No difference in implant survival was reported between test and control groups. Six studies reported a beneficial effect of platelet concentrates based on histomorphometric outcomes, while another six studies found no significant effect. A large heterogeneity was found regarding study design, surgical techniques, graft materials, clinical and histomorphometric outcome variables, and methods for preparing platelet concentrates. Favorable effects on soft tissue healing and postoperative discomfort reduction were often reported but not quantified.

CONCLUSIONS

A clear advantage of platelet concentrates could not be evidenced. Standardization in the experimental design is needed in order to detect the true effect of platelet concentrates in maxillary sinus augmentation procedure, especially regarding postoperative quality of life.

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.

Platelet-rich plasma in sinus augmentation procedures: a systematic literature review: Part II

BACKGROUND

Although platelet-rich plasma (PRP) has been extensively studied for over a decade, there are no definitive reports, which prove the benefit of using PRP in sinus augmentation procedures. In addition, no systematic literature review has been done to report the benefit of treatment outcome in patients who received PRP in conjunction with bone/bone substitutes in maxillary sinus augmentation procedures. Therefore, it can be rightly stated that evidence for an adjunctive benefit of using PRP with bone grafts in sinus augmentation procedures is equivocal and inconclusive.

AIM

: The objective of this systematic literature review was to examine this literature in determining whether PRP with bone and bone substitutes leads to more rapid and effective bone regeneration clinically, radiographically, and histologically with sinus augmentation procedures and was there any clinical data parallel to animal experiments providing clinical evidence in sinus augmentation procedures?

METHODS

A systematic review of randomized clinical trials of at least 6 months duration was conducted comparing PRP and bone/bone substitutes (test group) to bone/bone substitutes (control group) alone. Electronic databases such as MEDLINE and CENTRAL (Cochrane central register of controlled clinical trials) were searched for relevant articles. The reference list of all included articles was searched along with unpublished clinical trials whose abstracts were available.

RESULTS

Although, there is a lack of human studies, which show benefit of using PRP in conjunction with bone grafting materials, it can be stated that use of PRP does lead to early regeneration and reduction in healing time of soft and hard tissues. However, no significant statistical or clinical benefit was reported from studies that would satisfy the inclusion criteria. This study answers the question very clearly that at this point of time, there is no human study that strongly supports the benefit of using PRP in sinus augmentation procedures.

CONCLUSION

There is a paucity of clinically controlled trials regarding benefits of PRP in sinus augmentation procedures. Theoretically, it seems to have significant beneficial effects on the soft and hard tissue healing; however, the disparity in study design, surgical techniques, and different outcome assessment variables used, makes it difficult to assess the practical benefit of its clinical use. Although no obvious positive effects of PRP on healing of bone graft material in maxillary sinus augmentation procedures were noted, the handling of the particulate bone grafts was improved.

Interventions for replacing missing teeth: augmentation procedures of the maxillary sinus

BACKGROUND

Insufficient bone volume is a common problem encountered in the rehabilitation of the edentulous posterior maxillae with implant-supported prostheses. Bone volume is limited by the presence of the maxillary sinus together with loss of alveolar bone height. Sinus lift procedures increase bone volume by augmenting the sinus cavity with autogenous bone and/or commercially available biomaterials.

OBJECTIVES

To determine whether and when augmentation of the maxillary sinus are necessary and which are the most effective augmentation techniques for rehabilitating patients with implant-supported prostheses.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched on 7th January 2010. Several dental journals were handsearched. The bibliographies of review articles were checked, and personal references were searched. More than 55 implant manufacturing companies were also contacted.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of different techniques and materials for augmenting the maxillary sinus for rehabilitation with dental implants reporting the outcome of implant success/failure at least to abutment connection.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and odds ratios for dichotomous outcomes with 95% confidence intervals. The statistical unit of the analysis was the patient.

MAIN RESULTS

Ten RCTs out of 29 met the inclusion criteria. One trial of 15 patients evaluated implants 5 mm long with 6 mm diameter as an alternative to sinus lift in bone with a residual height of 4 to 6 mm. Nine trials with 235 patients compared different sinus lift techniques; of these four trials (114 patients) evaluated the efficacy of platelet-rich plasma (PRP). Due to the variety of techniques evaluated, meta-analysis was only possible of use of PRP for implant failure (two trials) and complications (three trials). No statistically significant difference was observed.

AUTHORS' CONCLUSIONS

Conclusions are based on few small trials, with short follow-up, and judged to be at high risk of bias. Therefore conclusions should be viewed as preliminary and interpreted with great caution. It is still unclear when sinus lift procedures are needed. 5 mm short implants can be successfully loaded in maxillary bone with a residual height of 4 to 6 mm but their long-term prognosis is unknown. Elevating the sinus lining in presence of 1 to 5 mm of residual bone height without the addition of a bone graft may be sufficient to regenerate new bone to allow rehabilitation with implant-supported prostheses. Bone substitutes might be successfully used as replacements for autogenous bone. If the residual alveolar bone height is 3 to 6 mm a crestal approach to lift the sinus lining, to place 8 mm implants may lead to fewer complications than a lateral window approach, to place implants at least 10 mm long. There is no evidence that PRP treatment improves the clinical outcome of sinus lift procedures with autogenous bone or bone substitutes.

Comparison of platelet-rich plasma, bovine BMP, and rhBMP-4 on bone matrix protein expression in vitro

This study investigated the potential use of platelet-rich plasma (PRP) in conjunction with mRNA expression of bone matrix proteins using bioassay and RT-PCR comparing bovine bone morphogenetic proteins (BMP), recombinant human BMP-4 (rhBMP-4) during rat bone marrow stromal cell (Mesenchymal Stem Cell) differentiation at 14 days. The results showed that all three growth factors were associated with significantly elevated alkaline phosphatase activity. PRP and bovine BMP resulted in increased protein content. The mRNA of type I collagen was expressed with all three growth factors and remained consistently elevated. Osteopontin was observed with PRP from days 1 to 7; bone sialoprotein expression was detected on days 1 and 3. PRP, bovine BMP and rhBMP-4 enhanced the steady-state expression of PDGF-A as time-dependent to day 14 and in PRP was the strongest. PTHr was expressed at days 1 and 5. Vascular endothelial growth factor expression was the most highly expressed after day 3. These findings suggest that PRP increases mRNA expression of bone matrix protein, enchances osteogenesis and angiogenesis in vitro.

Minimally invasive antral membrane balloon elevation - results of a multicenter registry

BACKGROUND AND PURPOSE

Frequently, the posterior maxilla lacks sufficient bone mass to support dental implants. This multiphysician registry assessed the feasibility and safety of minimally invasive antral membrane balloon elevation (MIAMBE), followed by bone augmentation and implant fixation.

MATERIALS AND METHODS

One hundred twelve consecutive patients were referred for MIAMBE. Following pre-procedural assessment and informed consent, patients underwent alveolar crest exposure, and 3 mm osteotomy followed by MIAMBE. Platelet-rich fibrin and bone substitutes were injected under the antral membrane; implant placement and primary closure were executed at the same sitting. Implant loading was carried out 6 to 9 months later.

RESULTS

One hundred nine (97.3%) patients successfully concluded the initial procedure. Three patients had membrane tear requiring procedure abortion. One case of infection was documented at 4 weeks. Procedure time was 58 +/- 23 minutes. Incremental bone height consistently exceeded 10 mm, and implant survival of 95% was observed at 6 to 9 months.

CONCLUSION

MIAMBE can be applied to all patients in need of posterior maxilla bone augmentation with high procedural success, low complication rate, and satisfactory bone augmentation and implant survival. As it is minimally invasive and associated with minimal discomfort, MIAMBE should be an alternative to the currently employed methods of maxillary bone augmentation.

A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation

OBJECTIVES

The objectives of this systematic review were to assess the survival rate of grafts and implants placed with sinus floor elevation.

MATERIAL AND METHODS

An electronic search was conducted to identify studies on sinus floor elevation, with a mean follow-up time of at least 1 year after functional loading.

RESULTS

The search provided 839 titles. Full-text analysis was performed for 175 articles resulting in 48 studies that met the inclusion criteria, reporting on 12,020 implants. Meta-analysis indicated an estimated annual failure rate of 3.48% [95% confidence interval (CI): 2.48%-4.88%] translating into a 3-year implant survival of 90.1% (95% CI: 86.4%-92.8%). However, when failure rates was analyzed on the subject level, the estimated annual failure was 6.04% (95% CI: 3.87%-9.43%) translating into 16.6% (95% CI: 10.9%-24.6%) of the subjects experiencing implant loss over 3 years.

CONCLUSION

The insertion of dental implants in combination with maxillary sinus floor elevation is a predictable treatment method showing high implant survival rates and low incidences of surgical complications. The best results (98.3% implant survival after 3 years) were obtained using rough surface implants with membrane coverage of the lateral window.

Autologous platelet concentrates for bone graft enhancement in sinus lift procedure

BACKGROUND

Autologous platelet (PLT)-rich plasma has been reported in some studies to promote osteogenesis. The goal of this study was to demonstrate that osteogenesis gained by mixing autologous PLT concentrates (APCs) with a small quantity of autologous bone graft could give a sufficient quality to lead to dental implant placement. The second goal was to compare this osteogenesis with that obtained by a traditional method (iliac bone graft), through clinical, radiologic, and histologic methods.

STUDY DESIGN AND METHODS

Eighteen patients needing bilateral sinus floor augmentation were enrolled. One sinus was grafted with iliac crest bone alone, and the other sinus with a small quantity of bone and APC. Panoramic view, computed tomography scan, and biopsies were performed 6 months after the initial surgery to compare ossification.

RESULTS

The adjunction of APCs permitted a 60 percent reduction of bone graft required for sinus floor elevation. The bone obtained with APCs had the same histologic and mechanical characteristics as the bone obtained by traditional graft.

CONCLUSION

Topical use of APCs might be helpful in bone reconstruction. No clinical, radiologic, or histologic osteogenesis inhibition of high PLT concentration was observed. The resulting osteogenesis was adapted to dental implant placements.

Efficacy and safety of the use of autologous plasma rich in platelets for tissue regeneration: a systematic review

BACKGROUND

Autologous plasma rich in platelets (PRP) is a derived blood product whose application in clinical practice is growing. A systematic review was conducted to evaluate its efficacy and safety.

STUDY DESIGN AND METHODS

A search was performed in electronic databases. Randomized controlled clinical trials (RCTs) in adult patients were included and assessed for methodologic quality. The main outcomes were "tissue regeneration" and "safety." Relative risks (RRs) and standardized mean differences (SMDs) were calculated to show pooled estimates for these outcomes. When the results heterogeneity was more than 50 percent, a sensitivity analysis was performed.

RESULTS

Twenty RCTs were included (11 of oral and maxillofacial surgery, 7 of chronic skin ulcers, and 2 of surgery wounds). Four RCTs evaluated the depth reduction in gingival recession in chronic periodontitis; the SMD was 0.54 (95% confidence interval [CI], 0.16 to 0.92) mm, favorable to PRP. Three RCTs evaluated the clinical attachment level in chronic periodontitis; the SMD was 0.33 (95% CI, -0.71 to 1.37) mm. Six RCTs assessed the complete skin epithelialization in wound ulcers; the RR was 1.40 (95% CI, 0.85 to 2.31). Only 6 RCTs reported adverse effects without differences between groups.

CONCLUSIONS

PRP improves the gingival recession but not the clinical attachment level in chronic periodontitis. In the complete healing process of chronic skin ulcers, the results are inconclusive. There are little data about PRP safety. There are several methodologic limitations and, consequently, future research should focus on strong and well-designed RCTs that assess the efficacy and safety of PRP.

Platelet-rich plasma induces mRNA expression of VEGF and PDGF in rat bone marrow stromal cell differentiation

OBJECTIVE

To investigate the potentially useful of platelet-rich plasma (PRP) on mRNA expression of angiogenesis.

STUDY DESIGN

Adjunct assay and reverse-transcription polymerase chain reaction (RT-PCR) analysis of type I collagen, vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF) in rat bone marrow stromal cells differentiation in 14 days' culture.

RESULTS

The PRP significantly elevated alkaline phosphatase activity after day 5 (P < .05), and DNA and protein content increased at culture days 1, 3, and 5 (P < .01) with PRP compared with control. The RT-PCR demonstrated that type I collagen was expressed in all substrates and remained high with PRP during 14 days of culture, and that mRNA expression of VEGF and PDGF were higher over time.

CONCLUSIONS

This study indicates a potential contribution of PRP as possibly starting the process of angiogenesis, recruiting the endothelial cells which line blood vessels, and beginning the initiation of bone regeneration.

Effect of solely applied platelet-rich plasma on osseous regeneration compared to Bio-Oss: a morphometric and densitometric study on rabbit calvaria

BACKGROUND

The use of platelet-rich plasma (PRP) in bone augmentation procedures is well documented; however, the exact benefit of this material is not yet established.

PURPOSE

This study aimed to evaluate the benefits of using PRP, when only used, and compare it to Bio-Oss (Geistlich Biomaterials, Wolhusen, Switzerland) in vertical bone augmentation capacity.

MATERIALS AND METHODS

The study was performed in calvaria of eight adult female New Zealand rabbits using titanium bone conduction cylinder. Two titanium cylinders were fixed into perforated slits made on the parietal bone of each rabbit. On each rabbit, one chamber was grafted with Bio-Oss, and the contralateral was filled with PRP. Animals were sacrificed 4 weeks after intervention and biopsies were taken. Densitometric, histological, and histomorphometric analyses were performed to evaluate bone mineral density, vertical bone augmentation, and remaining graft volume, respectively. Statistical analyses were performed with Mann-Whitney test, using a significance level of p < .05.

RESULTS

Densitometric and histomorphometric data analysis revealed that mean bone mineral densities and bone augmentation were significantly lower in the cylinders treated with PRP (p < .0001) 4 weeks after implantation.

CONCLUSION

This study showed no beneficial effect of using PRP on osseous regeneration. In addition, it was emphasized that Bio-Oss presents good osteoconductive properties by achieving suitable bone volume values.

Interventions for replacing missing teeth: bone augmentation techniques for dental implant treatment

BACKGROUND

Dental implants require sufficient bone to be adequately stabilised. For some patients implant treatment would not be an option without bone augmentation. A variety of materials and surgical techniques are available for bone augmentation.

OBJECTIVES

General objectives: To test the null hypothesis of no difference in the success, function, morbidity and patient satisfaction between different bone augmentation techniques for dental implant treatment.

SPECIFIC OBJECTIVES

(A) to test whether and when augmentation procedures are necessary; (B) to test which is the most effective augmentation technique for specific clinical indications. Trials were divided into three broad categories according to different indications for the bone augmentation techniques: (1) major vertical or horizontal bone augmentation or both; (2) implants placed in extraction sockets; (3) fenestrated implants.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE were searched. Several dental journals were handsearched. The bibliographies of review articles were checked, and personal references were searched. More than 55 implant manufacturing companies were also contacted. Last electronic search was conducted on 9th January 2008.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of different techniques and materials for augmenting bone for implant treatment reporting the outcome of implant therapy at least to abutment connection.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and odd ratios for dichotomous outcomes with 95% confidence intervals. The statistical unit of the analysis was the patient.

MAIN RESULTS

Seventeen RCTs out of 40 potentially eligible trials reporting the outcome of 455 patients were suitable for inclusion. Since different techniques were evaluated in different trials, no meta-analysis could be performed. Ten trials evaluated different techniques for vertical or horizontal bone augmentation or both. Four trials evaluated different techniques of bone grafting for implants placed in extraction sockets and three trials evaluated different techniques to treat bone dehiscence or fenestrations around implants.

AUTHORS' CONCLUSIONS

Major bone grafting procedures of resorbed mandibles may not be justified. Bone substitutes (Bio-Oss or Cerasorb) may replace autogenous bone for sinus lift procedures of atrophic maxillary sinuses. Various techniques can augment bone horizontally and vertically, but it is unclear which is the most efficient. It is unclear whether augmentation procedures at immediate single implants placed in fresh extraction sockets are needed, and which is the most effective augmentation procedure, however, sites treated with barrier plus Bio-Oss showed a higher position of the gingival margin when compared to sites treated with barriers alone. Non-resorbable barriers at fenestrated implants regenerated more bone than no barriers, however it remains unclear whether such bone is of benefit to the patient. It is unclear which is the most effective technique for augmenting bone around fenestrated implants. Bone morphogenetic proteins may enhance bone formation around implants grafted with Bio-Oss. Titanium may be preferable to resorbable screws to fixate onlay bone grafts. The use of particulate autogenous bone from intraoral locations, also taken with dedicated aspirators, might be associated with an increased risk of infective complications. These findings are based on few trials including few patients, sometimes having short follow up, and often being judged to be at high risk of bias.

Effect of platelet-rich plasma on bone regeneration in dentistry: a systematic review

OBJECTIVE

To review systematically the reported effects of platelet-rich plasma (PRP) on bone regeneration.

MATERIAL AND METHODS

Up to June 2006, MEDLINE and Cochrane databases were explored with different combinations of three search terms: 'PRP', 'bone regeneration', 'dentistry' and their synonyms.

INCLUSION CRITERIA

human controlled clinical trials designed to treat maxillofacial bony defects with application of PRP (test) or without PRP (control), including at least five patients with a follow-up period of more than 3 months and using clinical assessment, radiography, histology and/or histomorphometry for evaluation. Literature search, selection of eligible articles and data extraction were carried out independently by two readers.

RESULTS

The literature search revealed 108 references, of which 17 were selected for further analysis. Finally, nine articles fulfilling the inclusion criteria were selected for systematically review. Owing the substantial heterogeneity of the studies it was not possible to analyze the data statistically. An attempt was made to compare results from studies that used similar outcome measures by calculating and adding confidence intervals to the data presented in the original papers. Differences in treatment effects for periodontal defects in terms of clinical attachment level (CAL) were significant (ranging from 0.8 to 3.2 mm). The reported effects of PRP in sinus elevation (compared with their controls) were <10%.

CONCLUSION

We found evidence for beneficial effects of PRP in the treatment of periodontal defects. Evidence for beneficial effects of PRP in sinus elevation appeared to be weak. No conclusions can be drawn about other applications of PRP in dentistry.

Single-stage sinus augmentation with cancellous iliac bone and anorganic bovine bone in the presence of platelet-rich plasma in the miniature pig

AIM

The aim of the present study was to evaluate the osseointegration of dental implants and bone formation in maxillary sinus grafting with autologous and anorganic bovine bone in the presence of platelet-rich plasma (PRP) in an established animal model.

MATERIAL AND METHODS

We performed bilateral maxillary sinus augmentation with 50% anorganic bovine bone and simultaneously inserted a titanium screw implant in five minature pigs. Six hundred microlitre autologous PRP were added to the left side (test). The right side (no PRP) served as control. Polychrome sequential labeling was performed. The animals were sacrificed 6 weeks after surgery. Undecalcified ground sections were evaluated by microradiography, digitized histomorphometry and under fluorescent light.

RESULTS

The mean bone implant content in the test and control group was 8.4% and 17.3% respectively (P=0.042). The mean height of newly formed mineralized bone in the augmented area of the test group was 3.6 mm and 5.7 mm respectively (P=0.342). In the PRP group, the mean area of newly formed bone in the base of the sinus was enhanced (75.23%) as compared to the control side (51.8%) (P=0.020(*)). Although PRP enhanced bone formation at the base of the maxillary sinus, it neither improved osseointegration of dental implants nor bone in-growth into the bone substitute under the selected experimental conditions.

Topical use of platelet-rich plasma to influence bone volume in maxillary augmentation: a prospective randomized trial

BACKGROUND AND OBJECTIVES

The atrophic posterior maxilla often requires restoration of the alveolar ridge due to a lack of bone quantity and quality before dental implant placement. The aim of this study was to verify the hypothesis that platelet-rich plasma (PRP) has an influence on bone density in the maxilla after sinus floor elevation in combination with autologous cancellous bone from the iliac crest. Therefore, a randomized, prospective, controlled trial was set up in two centres.

STUDY DESIGN AND METHODS

Fifty-three patients who underwent osteoplastic bone grafting for sinus floor elevation were included. The intervention group was treated with defined concentrations of PRP in addition to transplanted bone. Bone biopsy was performed 4 months after augmentation. Bone volume was then measured using the histomorphometric parameter bone volume.

RESULTS

The histomorphometric evaluation of the biopsies did not indicate superiority of any of the treatments in terms of bone volume.

CONCLUSION

Topical use of PRP did not improve maxillary bone volume either clinically relevant or statistically significant compared to that in conventionally treated patients. The use of PRP to support bone regeneration cannot be recommended as a standard method for maxillary augmentation.

Maxillary Sinus Augmentation Using Sinus Membrane Elevation and Peripheral Venous Blood for Implant-Supported Rehabilitation of the Atrophic Posterior Maxilla: Case Series

BACKGROUND

Dental implants need appropriate bone volume for adequate stability in the rehabilitation after tooth loss. In the severely atrophic posterior maxilla, the clinical success of implant treatment sometimes requires a vertical ridge augmentation in the maxillary sinus floor.

PURPOSE

The purpose of this investigation was to evaluate a maxillary sinus floor augmentation technique using a replaceable bone window, elevation of the membrane, placement of implants, and injection of the patient's own venous blood to fill the voids.

MATERIALS AND METHODS

Six patients with need of maxillary sinus floor augmentation participated in the study. After preparation of a replaceable bone window in the lateral aspect of the sinus and careful elevation of the Schneiderian membrane, a total of 14 Brånemark implants (TiUnite, MK III, Nobel Biocare AB, Göteborg, Sweden) were installed in the residual bone penetrating into the sinus cavity. The sinus cavity was then filled with peripheral venous blood and the bone window replaced and stabilized with a medical tissue glue (Aron Alpha A, Sankyo, Inc., Tokyo, Japan) to prevent blood leakage from the created compartment in the maxillary sinus.

RESULTS

After a healing period of a minimum of 6 months, new bone was successfully generated in all 14 implant sites as judged from radiographs. One of the 14 implants failed, corresponding to a survival rate of 92.9% after a follow-up period ranging 12 to 34 months.

CONCLUSIONS

The present case series demonstrate that the creation of a secluded space in the maxillary sinus and filling with venous blood results in bone formation at simultaneously installed dental implants over a 6-month period.

Platelet-rich plasma preparation using three devices: implications for platelet activation and platelet growth factor release

BACKGROUND

In this study, three commercial systems for the preparation of platelet-rich plasma (PRP) were compared and platelet growth factors release was measured.

METHODS

Ten healthy volunteers donated whole blood that was fractionated by a blood cell separator, and a table-top centrifuge to prepare PRP. Furthermore, an autologous growth factor filter was used to concentrate PRP fractionated by the blood cell separator. PRP was subsequently activated with autologously produced thrombin to degranulate the platelets to measure platelet-derived growth factor-AB (PDGF-AB), transforming growth factor-beta (TGF-beta), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF).

RESULTS

PRP contained significantly higher platelet counts compared with baseline values (p < 0.001). PDGF-AB concentrations were increased more than 18-fold in the platelet gel supernatant when the cell-separator and GPS were used, whereas only a 3-fold increase was seen with the AGF.

CONCLUSION

The three PRP devices enable the preparation of PRP for the release of high concentrations of platelet growth factor, but showed different harvesting capacities for the collection of concentrated platelets. The administration of thrombin for PRP activation resulted in the release of high concentrations of PDGF-AB and TGF-beta but only when PRP had not been activated during the preparation process in vitro.

The Role of Platelet-Rich Plasma in Sinus Augmentation: A Critical Review

Although the lateral wall sinus lift is a predictable clinical procedure to increase vertical bone height resulting in implant success rates comparable to that of native bone, the issue of extended healing periods remains troublesome. Clinicians and researchers have investigated several methods, including addition of growth factors and peptides, to reduce this healing time and enhance bone formation within the subantral environment. Platelet-rich plasma (PRP) is an autologous blood product containing high concentrations of several growth factors and adhesive glycoproteins. The incorporation of PRP into the sinus graft has been proposed as a method to shorten healing time, enhance wound healing, and improve bone quality. This article reviewed pertinent literature assessing the effect of PRP on sinus augmentation. Currently, the literature is conflicting with respect to the adjunctive use of PRP in sinus augmentation. Factors that may contribute to this variability include variable/inappropriate study design, underpowered studies, differing platelet yields, and differing graft materials used. In addition, methods of quantifying bone regeneration and wound healing differ between studies. At present, because of limited scientific evidence, the adjunctive use of PRP in sinus augmentation cannot be recommended. Further prospective clinical trials are urgently needed.