Twenty-five years of recombinant human growth factors rhPDGF-BB and rhBMP-2 in oral hard and soft tissue regeneration

Contemporary oral tissue engineering strategies involve recombinant human growth factor approaches to stimulate diverse cellular processes including cell differentiation, migration, recruitment, and proliferation at grafted areas. Recombinant human growth factor applications in oral hard and soft tissue regeneration have been progressively researched over the last 25 years. Growth factor-mediated surgical approaches aim to accelerate healing, tissue reconstruction, and patient recovery. Thus, regenerative approaches involving growth factors such as recombinant human platelet-derived growth factor-BB (rhPDGF-BB) and recombinant human bone morphogenetic proteins (rhBMPs) have shown certain advantages over invasive traditional surgical approaches in severe hard and soft tissue defects. Several clinical studies assessed the outcomes of rhBMP-2 in diverse clinical applications for implant site development and bone augmentation. Current evidence regarding the clinical benefits of rhBMP-2 compared to conventional therapies is inconclusive. Nevertheless, it seems that rhBMP-2 can promote faster wound healing processes and enhance de novo bone formation, which may be particularly favorable in patients with compromised bone healing capacity or limited donor sites. rhPDGF-BB has been extensively applied for periodontal regenerative procedures and for the treatment of gingival recessions, showing consistent and positive outcomes. Nevertheless, current evidence regarding its benefits at implant and edentulous sites is limited. The present review explores and depicts the current applications, outcomes, and evidence-based clinical recommendations of rhPDGF-BB and rhBMPs for oral tissue regeneration.

Maxillary Sinus Floor Augmentation With Allograft Alone Compared With Alternate Grafting Materials: A Systematic Review and Meta-Analysis

A meta-analysis of scientific literature was conducted to ascertain the superiority between allografts and other regenerative grafts for maxillary sinus floor augmentation (MSFA). Review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines and registered in PROSPERO-CRD42023392766. Electronic databases like PubMed, Google scholar and Ebsco Host were searched from 2000 to December 2022 for studies reporting MSFA using allografts or other regenerative grafts. Quality assessment of included studies was evaluated using the Cochrane risk of bias (ROB)-2 tool for randomized controlled trials through its domains. Risk of bias summary graph and ROB summary applicability concern were plotted using RevMan software version 5.3. The standardized mean difference was used as a summary statistic measure with random effect model and P value <0.05 as statistically significant. Four studies fulfilled the eligibility criteria and were included in qualitative synthesis, of which all 4 studies were suitable for meta-analysis. Pooled estimate through standardized mean difference signifies that new bone formation was more or less similar for both graft materials, whereas regenerative grafts showed more residual bone grafts (P>0.05). Publication bias through funnel plot showed symmetric distribution with the absence of systematic heterogeneity. Both allografts and other regenerative grafts are equally effective in the MSFA in terms of new bone formation, whereras regenerative grafts showed more residual bone grafts. Furthermore, randomized controlled trials are required to establish evidence in outcomes involving sinus floor augmentation and different graft materials.

Residual Bone Height and New Bone Formation after Maxillary Sinus Augmentation Procedure Using Biomaterials: A Network Meta-Analysis of Clinical Trials

BACKGROUND

Different factors may affect new bone formation following maxillary sinus floor augmentation for the rehabilitation of posterior edentulous maxilla. The purpose of this study was to determine the influence of residual bone height (RBH) on new bone formation after lateral sinus augmentation utilizing different biomaterials, through a network meta-analysis (NMA).

METHODS

PUBMED, Scopus, and Web of Science electronic databases were searched until 31 December 2022 to obtain relevant articles. A hand search was also conducted. Randomised controlled studies on maxillary sinus augmentation comparing different grafting materials in patients with atrophic posterior maxilla, in need of prosthetic rehabilitation, were included. The risk of bias was assessed following the guidelines of the Cochrane Collaboration. The primary outcome was new bone formation (NBF), assessed histomorphometrically. The statistical analysis was performed by splitting the data according to RBH (<4 mm and ≥4 mm).

RESULTS

A total of 67 studies were eligible for conducting NMA. Overall, in the included studies, 1955 patients were treated and 2405 sinus augmentation procedures were performed. The biomaterials used were grouped into: autogenous bone (Auto), xenografts (XG), allografts (AG), alloplasts (AP), bioactive agents (Bio), hyaluronic acid (HA), and combinations of these. An inconsistency factor (IF) seen in the entire loop of the XG, AP, and Bio+AP was found to be statistically significant. The highest-ranked biomaterials for the <4 mm RBH outcome were XG+AG, XG+AP, and Auto. Similarly, the surface under the cumulative ranking curve (SUCRA) of biomaterials for ≥4 mm RBH was Auto, Bio+XG, and XG+Auto.

CONCLUSION

There is no grafting biomaterial that is consistently performing better than others. The performance of the materials in terms of NBF may depend on the RBH. While choosing a biomaterial, practitioners should consider both patient-specific aspects and sinus clinical characteristics.

Clinical and patient-reported outcomes of tissue engineering strategies for periodontal and peri-implant reconstruction

Scientific advancements in biomaterials, cellular therapies, and growth factors have brought new therapeutic options for periodontal and peri-implant reconstructive procedures. These tissue engineering strategies involve the enrichment of scaffolds with living cells or signaling molecules and aim at mimicking the cascades of wound healing events and the clinical outcomes of conventional autogenous grafts, without the need for donor tissue. Several tissue engineering strategies have been explored over the years for a variety of clinical scenarios, including periodontal regeneration, treatment of gingival recessions/mucogingival conditions, alveolar ridge preservation, bone augmentation procedures, sinus floor elevation, and peri-implant bone regeneration therapies. The goal of this article was to review the tissue engineering strategies that have been performed for periodontal and peri-implant reconstruction and implant site development, and to evaluate their safety, invasiveness, efficacy, and patient-reported outcomes. A detailed systematic search was conducted to identify eligible randomized controlled trials reporting the outcomes of tissue engineering strategies utilized for the aforementioned indications. A total of 128 trials were ultimately included in this review for a detailed qualitative analysis. Commonly performed tissue engineering strategies involved scaffolds enriched with mesenchymal or somatic cells (cell-based tissue engineering strategies), or more often scaffolds loaded with signaling molecules/growth factors (signaling molecule-based tissue engineering strategies). These approaches were found to be safe when utilized for periodontal and peri-implant reconstruction therapies and implant site development. Tissue engineering strategies demonstrated either similar or superior clinical outcomes than conventional approaches for the treatment of infrabony and furcation defects, alveolar ridge preservation, and sinus floor augmentation. Tissue engineering strategies can promote higher root coverage, keratinized tissue width, and gingival thickness gain than scaffolds alone can, and they can often obtain similar mean root coverage compared with autogenous grafts. There is some evidence suggesting that tissue engineering strategies can have a positive effect on patient morbidity, their preference, esthetics, and quality of life when utilized for the treatment of mucogingival deformities. Similarly, tissue engineering strategies can reduce the invasiveness and complications of autogenous graft-based staged bone augmentation. More studies incorporating patient-reported outcomes are needed to understand the cost-benefits of tissue engineering strategies compared with traditional treatments.

Efficacy of biologics for alveolar ridge preservation/reconstruction and implant site development: An American Academy of Periodontology best evidence systematic review

BACKGROUND

The use of biologics may be indicated for alveolar ridge preservation (ARP) and reconstruction (ARR), and implant site development (ISD). The present systematic review aimed to analyze the effect of autologous blood-derived products (ABPs), enamel matrix derivative (EMD), recombinant human platelet-derived growth factor-BB (rhPDGF-BB), and recombinant human bone morphogenetic protein-2 (rhBMP-2), on the outcomes of ARP/ARR and ISD therapy (i.e., alveolar ridge augmentation [ARA] and maxillary sinus floor augmentation [MSFA]).

METHODS

An electronic search for eligible articles published from January 2000 to October 2021 was conducted. Randomized clinical trials evaluating the efficacy of ABPs, EMD, rhBMP-2, and rhPDGF-BB for ARP/ARR and ISD were included according to pre-established eligibility criteria. Data on linear and volumetric dimensional changes, histomorphometric findings, and a variety of secondary outcomes (i.e., clinical, implant-related, digital imaging, safety, and patient-reported outcome measures [PROMs]) were extracted and critically analyzed. Risk of bias assessment of the selected investigations was also conducted.

RESULTS

A total of 39 articles were included and analyzed qualitatively. Due to the high level of heterogeneity across studies, quantitative analyses were not feasible. Most studies in the topic of ARP/ARR revealed that the use of biologics rendered similar results compared with conventional protocols. However, when juxtaposed to unassisted healing or socket filling using collagen sponges, the application of biologics did contribute to attenuate post-extraction alveolar ridge atrophy in most investigations. Additionally, histomorphometric outcomes were positively influenced by the application of biologics. The use of biologics in ARA interventions did not yield superior clinical or radiographic outcomes compared with control therapies. Nevertheless, ABPs enhanced new bone formation and reduced the likelihood of early wound dehiscence. The use of biologics in MSFA interventions did not translate into superior clinical or radiographic outcomes. It was observed, though, that the use of some biologics may promote bone formation during earlier stages of healing. Only four clinical investigations evaluated PROMs and reported a modest beneficial impact of the use of biologics on pain and swelling. No severe adverse events in association with the use of the biologics evaluated in this systematic review were noted.

CONCLUSIONS

Outcomes of therapy after post-extraction ARP/ARR and ARA in edentulous ridges were comparable among different therapeutic modalities evaluated in this systematic review. Nevertheless, the use of biologics (i.e., PRF, EMD, rhPDGF-BB, and rhBMP-2) in combination with a bone graft material generally results into superior histomorphometric outcomes and faster wound healing compared with control groups.

Sinus Floor Augmentation Using Recombinant Human Bone Morphogenetic Protein-2 With Hydroxyapatite: Volume Assessment

INTRODUCTION

The aim of this study was to assess the efficacy of using bone morphogenetic protein-2 with hydroxyapatite granules (BMP-2/hydroxyapatite) during augmentation of maxillary sinus floor, with respect to changes in volume, relative to conventional bone graft materials.

METHOD AND MATERIALS

Twenty of 25 patients in the BMP-2/hydroxyapatite group, and 16 of 33 patients in the conventional materials group met the criteria for inclusion in this study. Computed tomography scans were performed preoperatively, immediately postoperatively, and at follow-up, approximately 6 months postoperatively. Changes in volume and height of both grafted materials were measured using 3-dimensional reconstruction software; these changes were compared between groups.

RESULTS

The mean (standard deviation) volumetric changes were 0.25 (0.11) cc and -0.07 (0.35) cc, and the mean rates of volumetric changes were 26.44% (7.78%) and -2.92% (30.92%) in BMP-2/hydroxyapatite and conventional materials groups, respectively. The mean height changes were 0.34 (0.73) mm and -0.63 (1.07) mm, and the mean rates of height changes were 3.67% (7.57%) and -5.95% (9.98%) in BMP-2/hydroxyapatite and conventional materials groups, respectively.

CONCLUSION

Compared with the conventional materials group, the BMP-2/hydroxyapatite group showed better maxillary sinus floor augmentation results in terms of volumetric changes and grafted material densities, and can provide predictably reliable outcomes.

Histological Evaluation of the Effects of Growth Factors in a Fibrin Network on Bone Regeneration

OBJECTIVE

The aim of this study was to evaluate the effect of mineralized plasmatic matrix (MPM), comprising a combination of synthetic graft and platelet concentrates, on bone regeneration.

METHODS

Critical size defects of 6-mm diameter were created on the tibias of 6 male sheep, with the animals subsequently assigned into 2 groups. Of the 5 bone defects generated per animal, 4 were randomly filled with MPM, beta-tricalcium phosphate graft (β-TCP), platelet-rich fibrin (PRF) + β-TCP, and autogenous graft. One defect was left empty as a control group. Animals were killed at 3 weeks (early healing group) and 6 weeks (late healing group). The specimens underwent histologic and histomorphometric analysis to evaluate new bone formation.

RESULTS

In both healing periods, new bone formation from autogenous bone was observed significantly more often than from biomaterials or the empty defect. The degree of new bone formation for MPM was significantly higher than that of the control group at all healing periods. In addition, it was significantly higher in both healing periods than that of β-TCP albeit only in the late healing period than that of the PRF + β-TCP combination. In all biomaterial groups, residual graft ratios decreased from early to late healing periods.

CONCLUSION

The results indicated that MPM, representing growth factors in a fibrin network, increases new bone formation in surgically created defects in sheep tibia as confirmed by histologic assessment.

Void space and long-term volumetric changes of maxillary sinus floor augmentation with comparison between hydroxyapatite soaked with bone morphogenetic protein 2 and anorganic bovine xenograft alone

PURPOSE

We hypothesized that the void volume after maxillary sinus floor augmentation (MSFA) with recombinant human bone morphogenetic protein-2 (rhBMP-2) would be larger than that without rhBMP-2, and filled with bone in the long term. The aim of this study was to analyze the occurrence of void space and long-term volumetric changes after MSFA with rhBMP-2 and hydroxyapatite (BMP-2/H).

MATERIAL AND METHODS

In 25 subjects, MSFA was performed with BMP-2/H (group I) or an anorganic bovine xenograft (group II). Computed tomography scans were taken twice, at 3 months (T1) and at least 24 months (T2) after surgery. Total volume (TV), bone volume (BV), and void volume (VV) were measured and analysed statistically.

RESULTS

While similar amounts of graft material were used, the TV was significantly larger in group I than in group II (p = 0.014). The VV showed a tendency to be larger in group I than in group II. VV reduction up to T2 was significantly greater in group I than in group II. Consequently, the BV at T2 was significantly greater in group I than in group II by 36% (p = 0.014).

CONCLUSION

This study showed that our hypothesis was valid. rhBMP-2 is effective for long-term bone regeneration after MSFA.

Do osteoconductive bone substitutes result in similar bone regeneration for maxillary sinus augmentation when compared to osteogenic and osteoinductive bone grafts? A systematic review and frequentist network meta-analysis

The purpose of this network meta-analysis was to identify the most effective biomaterials producing higher new bone formation (NBF) and lower residual graft (RG) and connective tissue (CT) following maxillary sinus augmentation (MSA), and to generate a ranking based on their performance. The MEDLINE, Embase, and CENTRAL databases were searched to identify randomized controlled trials (RCTs) published until March 2018, evaluating histomorphometric outcomes after MSA. Predictor variables were autogenous bone (AB), allografts (AG), xenografts (XG), alloplastic bone (AP), AB+XG, AB+AP, AG+XG, XG+AP, and grafts combined with autologous platelet concentrates/recombinant growth factors, mesenchymal stem cells (MSCs), or recombinant bone morphogenetic proteins (BMPs). Outcome variables were NBF%, RG%, and CT%. Healing time was considered. The weighted mean difference (WMD) with 95% confidence interval (CI) was calculated via frequentist network meta-analysis using Stata software. Fifty-two RCTs (1483 biopsies) were included. At a healing time <6 months, AB was superior to AP (WMD-10.66%, 95% CI-16.38% to -4.94%) and XG (WMD-7.93%, 95% CI-15.11% to -0.75%) for NBF. Regarding CT, AB was superior to XG+AP, AP, MSCs, and XG. At a healing time ≥6 months, NBF was higher for AB than AP (WMD-7.06%, 95% CI-12.59% to -1.52%). RG was lower in AB than AP (WMD 12.03%, 95% CI 3.04% to 21.03%), XG (WMD 14.62%, 95% CI 4.25% to 24.98%), and growth factors (WMD 12.32%, 95% CI 0.04% to 24.60%). The three highest ranked biomaterials for increasing NBF were AG+XG (95%, very low quality evidence), growth factors (69.9%, low quality evidence), and AB alone (69.8%, moderate quality evidence). The three highest ranked biomaterials for decreasing RG were BMPs (88.8%, very low quality evidence), AB alone (81.5%, moderate quality evidence), and AB+AP (58.9%, very low quality evidence). Finally, XG+AP (84.7%, low quality evidence), AP alone (77.7%, moderate quality evidence), and MSCs (76.1%, low quality evidence), were the three highest ranked biomaterials for decreasing the amount of CT. Network meta-analysis provided moderate quality evidence that AB alone is probably the best option to obtain greater NBF after MSA in the first 6 months after surgery. Additionally, the results of this network meta-analysis support the hypothesis that osteoconductive bone substitute materials should be combined with osteogenic or osteoinductive grafts for superior histomorphometric outcomes in MSA.

Evaluation of Space-Maintaining Sinus Membrane Using the Absorbable Screws in Sinus Lifting Bone Augmentation

PURPOSE

We investigated whether it was possible to perform a sinus lift maintaining absorbable screw material with biological activity.

MATERIALS AND METHODS

Thirty rabbits were used. The screws used in this study were unsintered hydroxyapatite/poly-L-lactic acid (uHA/PLLA) (uHA/PLLA group) and titanium alloy (Ti group). Some uHA/PLLA screws were treated with ultraviolet light (UV-uHA/PLLA group). Each group consisted of 10 rabbits, and 2 screws were implanted for 1 rabbit. The screws were implanted into the frontal bone. Rabbits were euthanized at 3 days, 1, 2, 3, and 4 weeks postoperatively and prepared for histological examination, BMP-2 cell staining, and micro-computed tomography (micro-CT) assessment.

RESULTS

At 1, 2, and 3 weeks, the UV uHA/PLLA group had significantly more bone contact and new bone ratio on histological assessment than the other 2 groups. At 1, 2, 3, and 4 weeks, micro-CT assessment revealed significant differences between the UV uHA/PLLA group and the other 2 groups.

CONCLUSIONS

Sinus lift surgery using absorbable screw allowed bone formation. The UV-treated hydroxyapatite/poly-L-lactic acid (uHA/PLLA) was superior for sinus lift bone augmentation using a screw.

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.

Sinus augmentation using a mini-pig model: Effect of ceramic and allogeneic bone biomaterials

BACKGROUND

Present clinical practice broadly relies on off-the-shelf allogeneic, xenogeneic or synthetic bone biomaterials in support of sinus augmentation. Also, recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge carrier (rhBMP-2/ACS) has been shown to support clinically relevant bone formation when used to augment the maxillary sinus.

OBJECTIVES

To evaluate local bone formation/dental implant osseointegration following implantation of two particulate bone biomaterials using the mini-pig sinus augmentation model.

METHODS

Nine adult Göttingen mini-pigs were used for evaluation of a biphasic ceramic (15%/85% HA/ß-TCP) and an allogeneic mineralized bone biomaterial. Treatments randomized to contralateral sinus sites included sham-surgery (control) and biomaterials. Two threaded dental implants (ø4.0 × 11.5 mm) were placed at each sinus site. The animals were euthanized at 8 weeks for histologic analysis.

RESULTS

Execution of the surgical protocol and healing was unremarkable. Limited infraorbital swelling was observed until suture removal. The biphasic ceramic and allogeneic bone biomaterials produced significantly increased bone formation (5.2 ± 1.9 mm and 4.9 ± 1.6 mm vs. 2.6 ± 0.5 mm, p < 0.05) and osseointegration (18.0 ± 6.0% and 25.1 ± 18.2% vs. 10.1 ± 8.0%, p < 0.05) over the sham-surgery control. No significant differences were observed between biomaterials.

CONCLUSIONS

Implantation of biphasic ceramic or allogeneic bone biomaterials enhances bone formation in the mini-pig maxillary sinus, however, dental implant bone support is incomplete resulting in overall limited osseointegration.

Histologic and Histomorphometric Comparison of Bone Regeneration Between Bone Morphogenetic Protein-2 and Platelet-Derived Growth Factor-BB in Experimental Groups

Efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human platelet-derived growth factor-BB (rhPDGF-BB) delivered via absorbable collagen sponge (ACS) on bone formation was evaluated in guinea pig tibias. Three-millimeter-circular bone tibia defects were created in 24 guinea pigs assigned randomly to 4 groups according to the following defect filling materials: ACS only, rhBMP-2+ACS, rhPDGF-BB+ACS, or empty. New bone formation was evaluated histologically and histomorphometrically at 15 (early healing) and 45 days (late healing). Mean new bone per total defect area ratio was 0.73, 0.57, 0.43, and 0.42 in rhBMP-2+ACS, rhPDGF-BB+ACS, ACS only, and empty groups at early healing, respectively. During early healing, significantly more new bone formation was observed in rhBMP-2+ACS and rhPDGF-BB+ACS groups than in the control groups. New bone formation was significantly higher with rhBMP-2+ACS than with rhPDGF-BB+ACS. Mean new bone per total defect area ratio was 0.81, 0.86, 0.74, and 0.75 in the rhBMP-2+ACS, rhPDGF-BB+ACS, ACS only, and empty groups at late healing, respectively. During late healing, new bone formation was significantly higher in the rhPDGF-BB+ACS group relative to both control groups, but the results did not differ significantly from those in the rhBMP-2+ACS group. New bone formation in the rhBMP-2+ACS group did not change significantly between the healing periods. In the rhPDGF-BB+ACS group, however, new bone formation was significantly higher in the late healing period. Both growth factors accelerated new bone formation in the early healing period. Although rhBMP-2 was more effective in the early healing period, the effects of rhPDGF-BB were longer lasting.

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

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

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.