Randomized and Controlled Clinical Trial of Bone Healing After Alveolar Ridge Preservation Using Xenografts and Allografts Versus Plasma Rich in Growth Factors

The Use of the Facial Sinus Wall as Bone Shell Onlay Graft for Maxillary Posterior Ridge Reconstruction: A Retrospective Case Series

PURPOSE

To evaluate the performance and clinical outcome of vertical and horizontal bone augmentation (VHBA) in posterior maxillary regions combining lateral window sinus floor elevation (LWSFE) with a horizontal bone shell technique applying the maxillary facial sinus wall as a bone plate.

MATERIALS AND METHODS

In 18 patients, LWSFE was combined with a horizontal bone shield augmentation procedure utilizing the maxillary facial sinus bone wall as a lateral bone plate. Both the sinus cavity and the lateral bone box created were grafted with a mixture of autogenous bone/venous blood and bovine bone mineral. The primary aim was to assess the performance of combined techniques enabling subsequent implant placement. Using radiographic measurements (preoperative, after VHBA, at implant placement, and at follow-up), bone gain/reduction of augmented horizontal ridge width (HRW) and vertical bone height (VBH) were evaluated. Additionally, clinical outcome assessing implant survival/success rate, marginal bone loss (MBL), and implant health (mucositis/peri-implantitis) was evaluated.

RESULTS

For the combined VHBA techniques, HRW and VBH increased significantly (p < 0.001) from preoperative 3.5 ± 1.4 mm/3.6 ± 2.1 mm to 9.7 ± 1.9 mm/18.0 ± 1.6 mm post-augmentation. However, HRW and VBH dimensions decreased up to 8.9 ± 1.8 mm/17.1 ± 1.4 mm at implant placement and 8.6 ± 1.7 mm/16.7 ± 1.3 mm at follow-up evaluation (3.8 ± 1.8 years; p < 0.001, respectively). Augmented bone reduction was significantly higher (-7.7%) between the augmentation procedure and implant placement than in the post-implant-placement period (-2.5%). All implants survived (100%) representing peri-implant MBL of -0.9 ± 0.7 mm, pocket depth of 3.4 + 1.8 mm, and prevalences of 5%/0% for peri-implant mucositis/peri-implantitis.

CONCLUSION

The combination of horizontal bone augmentation using local bone shield transfer from the maxillary facial sinus wall with LWSFE enables sufficient reconstruction of maxillary posterior ridge.

Does Injectable Platelet-Rich Fibrin Combined With Autogenous Demineralized Dentine Enhance Alveolar Ridge Preservation? A Randomized Controlled Trial

OBJECTIVE

The present trial evaluated the first-time application of autogenous demineralized dentin graft with injectable platelet-rich fibrin (ADDG + i-PRF) versus autogenous demineralized dentin graft (ADDG), in alveolar ridge preservation (ARP) in the maxillary aesthetic zone.

MATERIAL AND METHODS

Twenty-two maxillary (n = 22) non-molar teeth indicated for extraction were randomized into two groups (n = 11/group). Extracted teeth were prepared into ADDG, implanted into extraction sockets with or without i-PRF amalgamation and covered by collagen sponge. Cone-beam computed tomography scans at baseline and 6 months were compared to assess ridge-dimensional changes. Keratinized tissue width, patient satisfaction, pain score and chair time were recorded. In the course of dental implant placements at 6 months, bone core biopsies of engrafted sites were obtained and analysed histomorphometrically.

RESULTS

Reduction in ridge width was 1.71 ± 1.08 and 1.8 ± 1.35 mm, while reduction in ridge height was 1.11 ± 0.76 and 1.8 ± 0.96 mm for ADDG + i-PRF and ADDG, respectively (p > 0.05). Significant differences in keratinized tissue width reduction were notable between ADDG + i-PRF and ADDG (0.12 ± 0.34 and 0.58 ± 0.34 mm respectively; p = 0.008). Postoperative pain scores were significantly lower in ADDG + i-PRF (p = 0.012). All patients in the two groups were satisfied with no differences in chair time (p > 0.05). No differences in total percentage area of newly formed bone, soft tissue or graft particles were observed between the groups (p > 0.05).

CONCLUSIONS

ADDG alone or in combination with i-PRF yields similar results regarding ARP clinically, quality of the formed osseous tissues, as well as patients' satisfaction. Yet, the addition of i-PRF to ADDG tends to preserve the keratinized tissue and lessen postoperative pain.

Autologous platelet concentrates in alveolar ridge preservation: A systematic review with meta-analyses

In order to evaluate the therapeutic advantages of various autologous platelet concentrates (APC) as a single biomaterial during alveolar ridge preservation (ARP), a systematic review with meta-analyses was conducted. PubMed, EMBASE, Web of Science, and Scopus were screened for randomized controlled trials (RCTs) that were released prior to 2024. The selected papers compared an APC with either unassisted healing (blood clot) or another biomaterial during ARP (third molars were not included). The outcome parameters included alveolar bone dimension alterations, soft tissue healing, and post-op pain intensity. The search yielded 35 papers (33 studies), one applying platelet-rich plasma (PRP), six using plasma rich in growth factors (PRGF), and 28 using leukocyte- and platelet-rich fibrin (L-PRF). These studies showed a large heterogeneity (e.g., outcome parameters, timing, surgical approach, and inclusion criteria), which hindered drawing strong conclusions. In most studies, however, ARP with PRP, PRGF, and L-PRF alone produced faster soft tissue healing, less post-extraction pain, less alveolar ridge resorption, more socket bone fill, and a higher bone density when compared to unassisted (spontaneous) healing. The ultimate benefit appears to be significantly influenced by the surgical approach. Limited literature exists comparing APC with other biomaterials for ARP, resulting in inconclusive data. APC application for ARP is a promising strategy to improve soft and hard tissue healing and reduce post-extraction pain.

A systematic review and meta-analysis on the use of regenerative graft materials for socket preservation in randomized clinical trials

OBJECTIVE

To evaluate if regenerative materials with/without scaffold deployed in dental socket preservation led to reduced radiographic height and width bone resorption.

STUDY DESIGN

English-written human studies from January 2010 to December 2023 were selected from PubMed, EMBASE, MEDLINE, Cochrane CENTRAL, Google Scholar and manually searched journals. Six meta-analyses were conducted, addressing treatments with all blood-derived growth factor preparations as well as L-platelet-rich fibrin (L-PRF) separately, and recombinant human BMP-2 (rhBMP-2). An unpaired t-test on L-PRF and rhBMP-2 determined the clinically best preservation treatment. Cochrane risk of bias in all studies was analyzed.

RESULTS

Twenty-nine articles (1068 participants) were included. Meta-analyses on blood-derived preparations demonstrated nonsignificant alveolar width, but significant (p = .001) height preservation. L-PRF vs. natural healing demonstrated nonsignificant changes in both dimensions. RhBMP-2 caused highly significant reduced horizontal (p = .01) and vertical (p < .0008) bone resorptions. When comparing mean resorption rates, significant benefits of rhBMP-2 over L-PRF were observed for width but not height preservation (p < .0001 and p = .057, respectively). Six studies recorded low, 8 moderate, and 15 high net risks.

CONCLUSIONS

Regenerative materials appear beneficial for radiographic bone width and height preservation after tooth extraction. Although rhBMP-2 performed better in alveolar width preservation, L-PRF can be an autologous and cost-effective alternative.

Changes of the Alveolar Bone Ridge Using Bone Mineral Grafts and Collagen Membranes after Tooth Extraction: A Systematic Review and Meta-Analysis

BACKGROUND

Alveolar preservation techniques for esthetic or functional purposes, or both, are a frequently used alternative for the treatment of post-extraction sockets, the aim of which is the regeneration of the lesion and the preservation of the alveolar bone crest.

METHODS

Studies published in PubMed (Medline), Web of Science, Embase, and Cochrane Library databases up to January 2024 were consulted. Inclusion criteria were established as intervention studies, according to the PICOs strategy: adult subjects undergoing dental extractions (participants), with alveoli treated with bone mineral grafts and collagen membranes (intervention), compared to spontaneous healing (comparison), and observing the response to treatment in clinical and radiological measures of the alveolar bone crest (outcomes).

RESULTS

We obtained 561 results and selected 12 studies. Risk of bias was assessed using the Cochrane Risk of Bias Tool, and methodological quality was assessed using the Joanna Briggs Institute. Due to the high heterogeneity of the studies (I2 > 75%), a random-effects meta-analysis was used. Despite the trend, no statistical significance (p > 0.05) was found in the experimental groups.

CONCLUSIONS

The use of bone mineral grafts in combination with resorbable collagen barriers provides greater preservation of the alveolar ridge, although more clinical studies are needed.

Plasma Rich in Growth Factors in Bone Regeneration: The Proximity to the Clot as a Differential Factor in Osteoblast Cell Behaviour

The osteogenic differentiation process, by which bone marrow mesenchymal stem cells and osteoprogenitors transform into osteoblasts, is regulated by several growth factors, cytokines, and hormones. Plasma Rich in Growth Factors (PRGF) is a blood-derived preparation consisting of a plethora of bioactive molecules, also susceptible to containing epigenetic factors such as ncRNAs and EVs, that stimulates tissue regeneration. The aim of this study was to investigate the effect of the PRGF clot formulation on osteogenic differentiation. Firstly, osteoblast cells were isolated and characterised. The proliferation of bone cells cultured onto PRGF clots or treated with PRGF supernatant was determined. Moreover, the gene expression of Runx2 (ID: 860), SP7 (ID: 121340), and ALPL (ID: 249) was analysed by one-step real-time quantitative polymerase chain reaction (RT-qPCR). Additionally, alkaline phosphatase (ALPL) activity determination was performed. The highest proliferative effect was achieved by the PRGF supernatant in all the study periods analysed. Concerning gene expression, the logRGE of Runx2 increased significantly in osteoblasts cultured with PRGF formulations compared with the control group, while that of SP7 increased significantly in osteoblasts grown on the PRGF clots. On the other hand, despite the fact that the PRGF supernatant induced ALPL up-regulation, significantly higher enzyme activity was detected for the PRGF clots in comparison with the supernatant formulation. According to our results, contact with the PRGF clot could promote a more advanced phase in the osteogenic process, associated to higher levels of ALPL activity. Furthermore, the PRGF clot releasate stimulated a higher proliferation rate in addition to reduced SP7 expression in the cells located at a distant ubication, leading to a less mature osteoblast stage. Thus, the spatial relationship between the PRGF clot and the osteoprogenitors cells could be a factor that influences regenerative outcomes.

Do autologous platelet concentrates (APCs) have a role in intra-oral bone regeneration? A critical review of clinical guidelines on decision-making process

In the past decades, personalized regenerative medicine has gained increased attention. Autologous platelet concentrates (APCs) such as PRP, PRGF, and L-PRF, all serving as a source of a large variety of cells and growth factors that participate in hard and soft tissue healing and regeneration, could play a significant role in regenerative periodontal procedures. This narrative review evaluated the relative impact of APCs in alveolar ridge preservation, sinus floor augmentation, and the regeneration of bony craters around teeth, both as a single substitute or in combination with a xenograft. L-PRF has a significant beneficial effect on alveolar ridge preservation (bone quality). The data for PRGF are less convincing, and PRP is controversial. L-PRF can successfully be used as a single substitute during transcrestal (≥3.5 mm bone gain) as well as 1-stage lateral window sinus floor elevation (>5 mm bone gain). For PRGF and especially PRP the data are very scarce. In the treatment of bony craters around teeth, during open flap debridement, L-PRF as a single substitute showed significant adjunctive benefits (e.g., >PPD reduction, >CAL gain, >crater depth reduction). The data for PRP and PRGF were non-conclusive. Adding PRP or L-PRF to a xenograft during OFD resulted in additional improvements (>PPD reduction, >CAL gain, >bone fill), for PRGF no data were found. Autologous platelet concentrates demonstrated to enhance bone and soft tissue healing in periodontal regenerative procedures. The data for L-PRF were most convincing. L-PRF also has the advantage of a greater simplicity of production, and its 100% autologous character.

Barbell Technique: A Novel Approach for Bidirectional Bone Augmentation: Clinical and Tomographic Study

Horizontal bone augmentation is a common surgical procedure used in implant therapy to achieve adequate bone volume to permit dental implant placement. However, most current techniques are focused on unidirectional bone reconstruction (grafting only on the buccal side). This study was carried out to validate a new device that will permit bidirectional bone augmentation. Ten patients of both sexes (7 women and 3 men), with ages ranging from 29 to 62 years, who needed a bidirectional horizontal bone augmentation in maxilla were separated in accordance with the horizontal alveolar change (HAC) classification published by Pelegrine et al (2018). The patients classified as HAC 3 (ie, containing remaining cancellous bone at the recipient bed) received the Barbell device with xenogeneic biomaterial and a collagen membrane, whereas HAC 4 patients (ie, with no remaining cancellous bone at the recipient bed) received the Barbell device with a mixture of autogenous bone chips and xenogeneic biomaterial covered by a collagen membrane. For each patient, two computerized tomography scans were performed (T0 at baseline and T1 at 6 months postoperative examinations). Mean bone thickness (T0) in the studied sites were 3.25 ± 0.35 in HAC 3 and 1.98 ± 0.5 in HAC 4 patients. The mean bone thickness achieved after 6 months was 7.70 ± 0.89 mm and 8.62 ± 0.89 in HAC 3 and 4, respectively. All grafted sites were able to receive dental implants in adequate prosthetic positions. Based on these results, the use of this novel device permits bidirectional horizontal bone augmentation.

Success of Xenografts in Alveolar Ridge Preservation Based on Histomorphometric Outcomes

Different xenograft approaches in alveolar ridge preservation (ARP) are essential to understand relative to their histomorphometric outcomes. Therefore, the aim of this study involved studying biomaterials of a xenograft nature that are used in ARP procedures, to compare the different approaches and evaluate their efficacy in relation to histomorphometric data. An electronic search was completed using the databases: Ovid (Medline), Google Scholar and Wiley Online Library, including a hand search for relevant articles and grey literature. Only randomised controlled trials, using xenograft biomaterials for alveolar ridge preservation procedures involving human studies, dated from 2010-2022 were included in the review. An initial search yielded 4918 articles, after application of the eligibility criteria, 18 studies were deemed eligible for inclusion in the systematic review. The two main xenograft groups found were of bovine origin and of porcine origin. The main histomorphometric outcomes evaluated included new bone percentage (N.B%) and residual graft percentage (R.G%). The mean N.B% for the bovine and porcine groups were 33.46% and 39.63% respectively and the mean R.G% for the bovine and porcine groups were 19.40% and 18.63% respectively. The current evidence suggests that the two main xenograft biomaterials used in ARP procedures after tooth extraction, which are of bovine and porcine origin, displayed effectiveness in producing new bone.

Effect of the use of platelet concentrates on new bone formation in alveolar ridge preservation: a systematic review, meta-analysis, and trial sequential analysis

OBJECTIVES

To investigate the histomorphometric changes occurring in alveolar ridge preservation (ARP) based on the use of different plasma concentrates (PCs) in randomized clinical trials (RCT). There is controversy whether the placement of PCs in ARP is effective in the formation of new bone.

MATERIALS AND METHODS

A systematic review search was conducted in PubMed, Scopus, Web of Science, and Cochrane Database to answer the PICO question: In patients undergoing tooth extraction followed by ARP, do PCs alone in the post-extraction socket in comparison with spontaneous healing improve new vital bone formation percentage in histomorphometric analysis after more than 10 weeks? The risk of bias was assessed and a meta-analysis was conducted.

RESULTS

Of 3809 results, 8 studies were considered suitable for inclusion. A total of 255 teeth were extracted in 250 patients. Regarding the PCs used, ARP was performed with platelet- and leukocyte-rich fibrin (L-PRF) in 120 sockets, and with pure platelet-rich plasma (P-PRP) in 31 sockets and 104 sockets were controlled. PCs improved new bone formation in ARP with respect to the spontaneous healing group (SMD = 1.77, 95%C.I. = 1.47-2.06, p-value < 000.1). There were no differences between the different PCs (L-PRF and P-PRP).

CONCLUSION

The results of this meta-analysis support the efficacy of the use of PCs in new bone formation in ARP. With respect to the different types of PCs studied, no differences were observed.

CLINICAL RELEVANCE

When planning implant surgery after tooth extraction, treatment with PCs should be considered for ARP. Any PC increases new bone formation compared to spontaneous healing.

Adjunctive Plasma Rich in Growth Factors in the Treatment of Osteomyelitis and Large Odontogenic Cysts Prior to Successful Implant Rehabilitation: Case Report

Osteomyelitis of the jaws presents a clinical challenge to conventional treatment, often requiring multiple surgical interventions resulting in significant deformity and presenting significant problems to satisfactory rehabilitation. While benign odontogenic cysts, such as the radicular cyst, are generally predictably treated, they can cause significant localized bone destruction and thus can present significant problems in satisfactory rehabilitation. In this case report, patients were treated combining conventionally appropriate surgical debridement and oral antibiotics with adjunctive plasma rich in growth factors (PRGF). Patients showed a complete soft tissue and osseous regeneration to their pre-pathologic state, with successful implant rehabilitation. PRGF appears to be highly successful in minimizing or eliminating osseous deformities normally associated with conventional treatment of osteomyelitis of the jaw and treatment of large odontogenic cysts. Future trials must be performed to confirm these results in comparison to controls using conventional treatment alone.

Two-Step Progressive Transcrestal Sinus Augmentation Using a 4.5 mm Unloaded Implant as a "Temporary Implant" in Highly Atrophic Ridge: Case Report

Severe atrophic posterior maxillary ridge (residual bone height < 3 mm) could be a challenging situation to place dental implants. Several treatment options have been proposed, but some of them may require advanced surgical skills to achieve best results. In this article, we present a novel and easier technique to allow implant placing in localized areas of severe atrophy. In a first step, a 4.5-length extra-short (unloaded) implant is placed after a transcrestal maxillary sinus floor augmentation (MSFA). After the gained apical bone consolidation, this "temporary implant" is atraumatically removed and a longer and wider definitive implant is placed to support the definitive single restoration. The case of a 45-year-old female treated with this approach is also presented. The patient suffered a severe resorption in the upper right molar area after a tooth extraction. Four months after the "temporary implant" placement and MSFA grafting with plasma rich in growth factors and autologous bone, 3 mm of dense apical bone gain could be observed. In a second surgical time, the 4.5 mm-length "temporary implant" was removed, and a 5.5 mm-length "definitive implant" was placed. This second implant was placed in a denser type 1 (1,000 Hounsfield Unit) new formed apical bone. Four months later, the implant was loaded with a screw-retained crown over a transepithelial (intermediate abutment). After 1-year follow-up, the implant was in health and no mechanical or biological complications were noticed. The satisfactory results of this case encourage the realization of new studies to elucidate its reproducibility.

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.

Unravelling Alveolar Bone Regeneration Ability of Platelet-Rich Plasma: A Systematic Review with Meta-Analysis

Background: This systematic review aims to evaluate the efficacy of the available platelet-rich plasma (PRP) products and composition to regenerate alveolar bone after tooth extraction. Methods: PubMed, Cochrane Central Register of Controlled Trials, and EBSCO databases were searched up to 2 July 2021. Only randomized clinical trials using leukocyte-rich plasma (L-PRP) or pure-platelet rich plasma (P-PRP) for bone regeneration in alveolar ridge preservation were selected. The following outcomes were considered: (1) new bone formation (primary outcome) and (2) bone density (secondary outcome). A meta-analysis for PRP, P-PRP, and L-PRP using a fixed effect model was performed with Review Manager 5.4 software. Overall evidence was qualified using GRADE. Results: Six randomized clinical trials from 2639 unique articles initially identified met the inclusion criteria. The meta-analysis showed a significant effect of the P-PRP on the outcome of new bone formation (SMD, 1.44; 95% CI, 0.84 to 2.03) for P-PRP treatment. No information was retrieved for L-PRP. A statistically significant difference was also observed in the P-PRP group for bone density outcome (SMD, 1.24; 95% CI, 0.81 to 1.68). The L-PRP treated sockets also showed higher bone density (SMD, 0.88; 95% CI, 0.31 to 1.45) in comparison to control sockets. The quality of evidence was moderate for both outcomes in the P-PRP group and low for the L-PRP group. Conclusions: Despite the limitations of the included studies, our data suggest that P-PRP, in comparison to unassisted healing, can improve alveolar bone regenerative potential. However, more high-quality clinical studies are needed.

Autologous Platelet Concentrates (APCs) for Hard Tissue Regeneration in Oral Implantology, Sinus Floor Elevation, Peri-Implantitis, Socket Preservation, and Medication-Related Osteonecrosis of the Jaw (MRONJ): A Literature Review

Simple Summary

Autologous platelet concentrates with high growth factor levels are used in many fields of dentistry. In recent years, the critical role of blood-derived materials in bone and soft tissue engineering has become apparent. After tooth extraction, the alveolar bone is exposed to progressive bone resorption, which can lead to difficulties in implant placement. Hence, many studies have demonstrated that APCs have the potential for soft tissue and bone regeneration. Furthermore, no inflammatory reactions occur, and they may be used alone or in combination with bone grafts, promoting bone growth and maturation. Moreover, the released growth factors and the presence of fibrin structures can induce osteogenesis. This review aims to provide information regarding the applications, indications, advantages, and disadvantages of three APC techniques in hard tissue regeneration.

Abstract

Over recent years, the usage of autologous platelet concentrates (APCs) has risen in hard tissue regeneration and oral implantology. The purpose of the present review is to offer an overview of the use of three APC techniques in dentistry: platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and concentrated growth factor (CGF). A narrative summary of articles published between January 2011 and April 2022 is provided. The PubMed, Cochrane Library, Scopus, and Embase databases were used to conduct the search. The following keywords were used in the preliminary: “VEGF”, “TGF-b1”, “PRP”, “PRF”, “CGF”, AND “sinus augmentation” OR “implants” OR “peri-implantitis” OR “socket preservation” OR “MRONJ”. A total of 82 articles was finally included. The review then takes into account the application of the three techniques in different areas of treatment—including oral implantology, sinus floor elevation, peri-implantitis, socket preservation, and medication-related osteonecrosis of the jaw (MRONJ)—as well as their advantages and disadvantages.

Dimensional and histomorphometric evaluation of biomaterials used for alveolar ridge preservation: a systematic review and network meta-analysis

OBJECTIVES

This systematic review and network meta-analysis aimed to answer to the following questions: (a) In patients undergoing alveolar ridge preservation after tooth extraction, which grafting material best attenuates horizontal and vertical ridge resorption, as compared to spontaneous healing?, and (b) which material(s) promotes bone formation in the extraction socket?

MATERIALS AND METHODS

The MEDLINE, SCOPUS, CENTRAL, and EMBASE databases were screened in duplicate for RCTs up to March 2021. Two independent authors extracted the data and assessed the risk of bias of the included studies. Primary outcomes were ridge horizontal and vertical dimension changes and new bone formation into the socket. Both pairwise and network meta-analysis (NMA) were undertaken to obtain estimates for primary outcomes and compare different grafting materials.

RESULTS

Eighty-eight RCTs were included, with a total of 2805 patients and 3073 sockets. Overall, a total of 1740 sockets underwent alveolar ridge preservation with different materials (1432 were covered by a membrane). Pairwise meta-analysis showed that, as compared to spontaneous healing, all materials statistically significantly reduced horizontal and vertical shrinkage. According to the multidimensional scale ranking of the NMA, xenografts (XG) and allografts (AG), alone or combined with bioactive agents (Bio + AG), were the most predictable materials for horizontal and vertical ridge dimension preservation, while platelet concentrates performed best in the percentage of new bone formation.

CONCLUSIONS

Alveolar ridge preservation is effective in reducing both horizontal and vertical shrinkage, as compared to untreated sockets. NMA confirmed the consistency of XG for ridge dimension preservation, but several other materials and combinations like AG, Bio + AG, and AG + alloplasts, produced even better results than XG in clinical comparisons. Further evidence is needed to confirm the value of such alternatives to XG for alveolar ridge preservation. Bio + AG performed better than the other materials in preserving ridge dimension and platelet concentrates in new bone formation. However, alloplasts, xenografts, and AG + AP performed consistently good in majority of the clinical comparisons.

CLINICAL RELEVANCE

XG and Bio + AG demonstrated significantly better performance in minimizing post-extraction horizontal and vertical ridge dimension changes as compared with other grafting materials or with spontaneous healing, even if they presented the worst histological outcomes. Allografts and other materials or combinations (AG + AP) presented similar performances while spontaneous healing ranked last.

The impact of autologous concentrated growth factors on the alveolar ridge preservation after posterior tooth extraction: A prospective, randomized controlled clinical trial

BACKGROUND

Alveolar ridge preservation can effectively decrease alveolar ridge resorption following tooth extraction, but it can be limited by reducing new bone formation and residual bone graft material. Efforts to develop more efficacious approaches are thus an area of active research.

PURPOSE

To assess the impact of autologous concentrated growth factors (CGF) on alveolar ridge absorption and osteogenesis following posterior tooth extraction.

MATERIALS AND METHODS

Fifty patients were randomly assigned to have extraction sockets treated with CGF or no treatment. At 10 days, 1 month, and 3 months postextraction, soft tissue color and texture were examined and evaluated with healing score. Cone-beam computed tomography (CBCT) scans were performed before and 3 months after extraction, while radiographic analyses were used to assess vertical and horizontal bone changes. Bone samples were collected from the extraction sockets during implant placement, and micro-computed tomography (micro-CT) scans and histological analysis were performed to evaluate new bone formation. t-Test or Mann-Whitney U test was used to compare data and the level of statistical significance was set at 0.05 for all analyses.

RESULTS

Forty-six patients completed the trial. Sockets in the experimental group exhibited significantly better healing score on Day 10 postextraction relative to the control group, whereas comparable healing was observed in both groups at 1 and 3 months postextraction. Experimental group exhibited reduced vertical bone changes relative to the control (p < 0.05). Significant reductions were observed in ridge width changes at 1 and 2 mm apical to the crest (p < 0.05), although differences at 3 and 5 mm apical to the crest were not significant. Significant differences of bone mineral density (BMD) and microarchitecture of trabecular bone were observed via micro-CT analyses, and the experimental group had better results.

CONCLUSION

CGF application following posterior tooth extraction may reduce vertical and horizontal bone resorption and promote new bone formation.

Spongostan™ Leads to Increased Regeneration of a Rat Calvarial Critical Size Defect Compared to NanoBone® and Actifuse

Bone substitute materials are becoming increasingly important in oral and maxillofacial surgery. Reconstruction of critical size bone defects is still challenging for surgeons. Here, we compared the clinically applied organic bone substitute materials NanoBone^® (nanocrystalline hydroxyapatite and nanostructured silica gel; n = 5) and Actifuse (calcium phosphate with silicate substitution; n = 5) with natural collagen-based Spongostan™ (hardened pork gelatin containing formalin and lauryl alcohol; n = 5) in bilateral rat critical-size defects (5 mm diameter). On topological level, NanoBone is known to harbour nanopores of about 20 nm diameter, while Actifuse comprises micropores of 200–500 µm. Spongostan™, which is clinically applied as a haemostatic agent, combines in its wet form both nano- and microporous topological features by comprising 60.66 ± 24.48 μm micropores accompanied by nanopores of 32.97 ± 1.41 nm diameter. Micro-computed tomography (µCT) used for evaluation 30 days after surgery revealed a significant increase in bone volume by all three bone substitute materials in comparison to the untreated controls. Clearly visual was the closure of trepanation in all treated groups, but granular appearance of NanoBone^® and Actifuse with less closure at the margins of the burr holes. In contrast, transplantion of Spongostan™ lead to complete filling of the burr hole with the highest bone volume of 7.98 ccm and the highest bone mineral density compared to all other groups. In summary, transplantation of Spongostan™ resulted in increased regeneration of a rat calvarial critical size defect compared to NanoBone and Actifuse, suggesting the distinct nano- and microtopography of wet Spongostan™ to account for this superior regenerative capacity. Since Spongostan™ is a clinically approved product used primarily for haemostasis, it may represent an interesting alternative in the reconstruction of defects in the maxillary region.

Three-dimensional analysis of dimensional changes after alveolar ridge preservation with bone substitutes or plasma rich in growth factors: Randomized and controlled clinical trial

OBJECTIVES

To evaluate alveolar ridge dimensional changes of different alveolar ridge preservation techniques after 3 months of tooth extraction and to compare the efficacy of autologous plasma rich in growth factor (PRGF) to the bone substitutes in alveolar ridge preservation and sites left to heal spontaneously.

MATERIALS AND METHODS

Forty patients requiring tooth extraction in the anterior maxilla were randomly allocated to the four following treatment modalities: spontaneous healing (control), natural bovine bone mineral covered with resorbable native collagen membrane (BBM/CM), freeze-dried bone allograft covered with resorbable native collagen membrane (FDBA/CM) and PRGF alone. Cone beam computed tomography (CBCT) scans were taken after surgery and 3 months later. The measurements of height and width (at 1, 3, and 5 mm below the crest) were performed after superimposing the 2 consecutive CBCT scans.

RESULTS

The greatest horizontal alveolar bone resorption at 1 mm below bone crest was observed in the control group (-1.61 ± 1.76 mm, P = .037), whereas the least reduction in width was found in the BBM/CM group (-0.68 ± 0.67 mm, P = .037). The most pronounced alveolar height reduction was observed in the control group (-0.86 ± 0.43 mm), whereas alveolar ridge preservation with BBMC/CM (-0.26 ± 0.91 mm) and PRGF (-0.54 ± 0.86 mm) successfully reduced the alveolar height reduction as compared to the control group.

CONCLUSIONS

Alveolar ridge preservation technique in the esthetic zone using BBM/CM or using PRGF is beneficial to reduce horizontal and vertical bone changes.

Biomimetic Aspects of Oral and Dentofacial Regeneration

Biomimetic materials for hard and soft tissues have advanced in the fields of tissue engineering and regenerative medicine in dentistry. To examine these recent advances, we searched Medline (OVID) with the key terms “biomimetics”, “biomaterials”, and “biomimicry” combined with MeSH terms for “dentistry” and limited the date of publication between 2010–2020. Over 500 articles were obtained under clinical trials, randomized clinical trials, metanalysis, and systematic reviews developed in the past 10 years in three major areas of dentistry: restorative, orofacial surgery, and periodontics. Clinical studies and systematic reviews along with hand-searched preclinical studies as potential therapies have been included. They support the proof-of-concept that novel treatments are in the pipeline towards ground-breaking clinical therapies for orofacial bone regeneration, tooth regeneration, repair of the oral mucosa, periodontal tissue engineering, and dental implants. Biomimicry enhances the clinical outcomes and calls for an interdisciplinary approach integrating medicine, bioengineering, biotechnology, and computational sciences to advance the current research to clinics. We conclude that dentistry has come a long way apropos of regenerative medicine; still, there are vast avenues to endeavour, seeking inspiration from other facets in biomedical research.