Alternatives to Autologous Bone Graft in Alveolar Cleft Reconstruction: The State of Alveolar Tissue Engineering

Does the adjunctive use of autologous platelet concentrate during secondary alveolar bone grafting reduce the risk of wound dehiscence? A systematic review and meta-analysis

Wound dehiscence is a common complication after secondary alveolar bone grafting (SABG), leading to unfavourable surgical outcomes. Studies have shown that autologous platelet concentrates (APC) may enhance wound healing and improve outcomes. Therefore, this review aimed to evaluate in patients with alveolar clefts, whether using APC and iliac crest bone graft can mitigate the likelihood of wound dehiscence formation compared with those who underwent iliac bone grafting only following SABG. A comprehensive literature search was conducted using various electronic databases, including PubMed, Embase, Scopus, Web of Science, EBSCOhost, Ovid MEDLINE, LILACS, Cochrane Library, and grey literature, to include studies until July 31, 2023, without any restriction to language and time of publication. Only randomized (RCT) and controlled (CCT) clinical trials were included. Two independent reviewers screened the studies based on the predefined criteria, after which a qualitative and quantitative analysis was conducted. The search yielded 821 studies, of which seven were deemed eligible for systematic review. The risk of bias assessment done using "The Cochrane collaboration tool for risk of bias assessment" for six RCTs and the "Risk of Bias in Non-randomized Studies - of Interventions" for one CCT revealed a moderate to high risk of bias. The meta-analysis of five studies showed that the overall risk of developing wound dehiscence was lower in the APC group (RR = 0.33; 95% CI: 0.16, 0.71; p = 0.005; χ2 = 0.82; I2 = 0%). Subgroup analyses based on study design further supported these findings. Although the adjuvant use of APC for alveolar cleft reconstruction reduces the risk of wound dehiscence, more studies with increased scientific rigour and fewer confounding variables are warranted.

Evaluation of Radiographic Outcomes of Alveolar Graft Associated with Premaxillary Osteotomy Performed with rhBMP-2

OBJECTIVE

To evaluate the influence of filling material and timing of surgery on radiograph outcomes of alveolar grafting with premaxillary osteotomy. The null hypothesis was that radiographic outcomes would be similar with both rhBMP-2 (rhBMP-2G) and cancellous bone from the iliac crest (IG), regardless of the timing of surgery.

DESIGN

Cross-sectional study with consecutive sampling of 56 periapical or occlusal radiographs taken 12 months after surgery.

SETTING

A single tertiary craniofacial center.

PATIENTS/PARTICIPANTS

Twenty-eight patients with complete bilateral cleft lip and palate and mean age of 13 years. The individuals underwent bilateral alveolar grafting associated with premaxillary osteotomy (AG + PO) with rhBMP-2 or cancellous bone from the iliac crest.

INTERVENTIONS

Experienced maxillofacial surgeons used the same surgical technique in both groups. AG + PO were assigned as success or failure by 3 blinded raters based on modified Bergland and SWAG scales.

MAIN OUTCOME MEASURES

The influence of filling materials and timing of surgery on radiographic outcomes was verified by Fisher's exact test and chi-square test (P < .05).

RESULTS

There was no significance variation between the mean age of participants in the rhBMP-2G and IG (P = .471). Scales showed almost perfect reliability (agreement rate = 96.4%; K = 0.85). rhBMP-2G and IG had similar success rates with modified Bergland scale (85.7% and 82.1%) and SWAG scale (92.9% and 82.1%), respectively. However, only modified Bergland scale found influence of age on radiographic outcomes (P = .025).

CONCLUSIONS

AG + PO performed with rhBMP-2 and iliac crest bone showed similar radiographic success rates, regardless of the timing of surgery.

Evaluation of the Regenerative Capacity of Demineralized Bone Matrix vs Fat Graft in Alveolar Cleft Model in Albino Rats

AIM

This study was performed to evaluate the regenerative capacity of demineralized bone matrix vs fat graft, both guided by pericardium membrane in alveolar cleft model in albino rats.

MATERIALS AND METHODS

A total of 72 rats were required in this study. A surgical bone defect with a 7 mm length × 4 mm width × 3 mm depth was created as a model of an alveolar cleft, then the rats were divided randomly into four equal groups each group contained 18 rats: control group (defect only), the membrane group (the defect was covered by the pericardium membrane), the demineralized bone matrix (DBM) group (the defect was filled with DBM guided by pericardium membrane) and fat group (the defect was filled with a fat graft guided by the pericardium membrane). Around 6 rats from each group were euthanized after 2, 4, and 8 weeks. Skulls were scanned with cone beam computed tomography (CBCT) and harvested for histological evaluation with routine H&E immunohistochemical stains (Anti-osteocalcin and Anti-Wnt5a). The data was recorded and statistically analyzed by a two-way ANOVA.

RESULTS

The study showed a notable formation of new bone, and expression of OCN and Wnt5a were notably increased by time in the fat group. However, the density of bone grafts and OCN and Wnt5a expression decreased with time in the DBM group. Control and membrane groups showed negative OCN and Wnt5a immune-reactivity in the cleft site.

CONCLUSION

Fat graft results were superior to DBM results with regard to mucosal closure and accelerated bone regeneration, and may represent an effective treatment for alveolar cleft reconstruction.

CLINICAL SIGNIFICANCE

Finding an inexpensive, accessible, biocompatible and easily manipulated treatment for craniofacial reconstruction and fat graft fulfilled the desired aims. Further investigations with prolonged evaluation periods are needed. How to cite this article: Abdel Raouf E, Elsherbini AM, Abdel Salam Yousef Y, et al. Evaluation of the Regenerative Capacity of Demineralized Bone Matrix vs Fat Graft in Alveolar Cleft Model in Albino Rats. J Contemp Dent Pract 2024;25(6):554-562.

Stem Cell-Based Regenerative Approaches for the Treatment of Cleft Lip and Palate: A Comprehensive Review

Cleft lip and/or palate (CLP) is a prevalent congenital craniofacial abnormality that can lead to difficulties in eating, speaking, hearing, and psychological distress. The traditional approach for treating CLP involves bone graft surgery, which has limitations, post-surgical complications, and donor site morbidity. However, regenerative medicine has emerged as a promising alternative, employing a combination of stem cells, growth factors, and scaffolds to promote tissue regeneration. This review aims to provide a comprehensive overview of stem cell-based regenerative approaches in the management of CLP. A thorough search was conducted in the Medline/PubMed and Scopus databases, including cohort studies, randomized controlled trials, case series, case controls, case reports, and animal studies. The identified studies were categorized into two main groups: clinical studies involving human subjects and in vivo studies using animal models. While there are only a limited number of studies investigating the combined use of stem cells and scaffolds for CLP treatment, they have shown promising results. Various types of stem cells have been utilized in conjunction with scaffolds. Importantly, regenerative methods have been successfully applied to patients across a broad range of age groups. The collective findings derived from the reviewed studies consistently support the notion that regenerative medicine holds potential advantages over conventional bone grafting and represents a promising therapeutic option for CLP. However, future well-designed clinical trials, encompassing diverse combinations of stem cells and scaffolds, are warranted to establish the clinical efficacy of these interventions with a larger number of patients.

Demineralized bone matrix for repair and regeneration of maxillofacial defects: A narrative review

OBJECTIVES

Demineralized bone matrix (DBM) is a well-established bone graft material widely accepted by dentists and the public for its favorable osteoconductivity and osteoinductive potential. This article aimed to provide a narrative review of the current therapeutic applications and limitations of DBM in maxillofacial bone defects.

STUDY SELECTION, DATA, AND SOURCES

Randomized controlled trials, prospective or retrospective clinical studies, case series and reports, and systematic reviews. MEDLINE, PubMed, and Google Scholar were searched using keywords.

CONCLUSIONS

Some evidence supported the therapeutic application of DBM in periodontal intrabony defects, maxillary sinus lifts, ridge preservation, ridge augmentation, alveolar cleft repair, orthognathic surgery, and other regional maxillofacial bone defects. However, the limitations of DBM should be considered when using it, including potential low immunogenicity, instability of osteoinductive potential, handling of the graft material, and patient acceptance.

CLINICAL SIGNIFICANCE

With the increasing demand for the treatment of maxillofacial bone defects, DBM is likely to play a greater role as a promising bone graft material. Safe and effective combination treatment strategies and how to maintain a stable osteoinductive potential will be the future challenges of DBM research.

Effectiveness of maxillary cortical bone graft chips harvested by bone scraper, covered with platelet-rich fibrin (PRF), in reconstruction of alveolar clefts: comparative study

PURPOSE

The aim of this study is to assess the effectiveness of maxillary cortical bone graft chips harvested by bone scraper, covered with platelet-rich fibrin (PRF) in alveolar clefts.

PATIENTS AND METHODS

Seventy-two cleft patients were examined for their eligibility to be part in this comparative study; they were randomly divided into group A, thirty-six patients had received cancellous bone chips from iliac crest; group B, thirty-six had received cortical bone chips harvested from maxilla using a curved bone scraper, covered with PRF. The clinical success over the follow-up period was evaluated on the basis of elimination of the oronasal fistula, radiographic assessment of bone graft volume, achievement of the osseous continuity of the alveolar arch, and the extent of the vertical bone height.

RESULTS

The mean of volume gained in group A was 0.8053 ± 0.9682, while for group B was 0.7397 ± 0.7703. The amount of vertical bone loss between groups was registered, and the chi-square test revealed insignificant differences between study groups (p = 0.547). The result of the frequency of fistula development after grafting in both groups was insignificant (p = 0.074). Also, for the continuity of the maxilla as a one piece, the results were insignificant differences between study groups (p = 0.058).

CONCLUSION

In conclusion of our study, intraoral harvesting of maxillary cortical chips by bone scraper covered with PRF is able to achieve a valid functional and aesthetic support in alveolar cleft patients, meeting the reconstructive goals.

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.

Early Results on the Efficacy of Demineralized Bone Matrix, Bone Morphogenic Protein, and Freeze-dried Bone Chips in Alveolar Cleft Repair

Background

Conventional treatment for alveolar cleft repair is done using autologous iliac crest alveolar bone graft (ABG). However, this method may not be ideal in all patients. Analysis of the efficacy of a mixture of demineralized bone matrix (DBX), bone morphogenic protein (rhBMP-2), and freeze-dried bone chips (FDBC) as an alternative for alveolar cleft repair was performed.

Methods

Consecutive patients from August 2019 to June 2022 undergoing early alveolar cleft repair, concomitant hard palate and alveolar cleft repair, secondary alveolar cleft repair, and regrafting from a previously failed ABG were analyzed. Computed tomography scans were performed to evaluate graft take at least 6 months postoperatively. Images were reviewed and scored. Alveolar graft height and graft thickness were recorded. A standardized scoring system was developed, with a score of 0 representing no graft take and 3 representing best possible graft take.

Results

Fifty-five consecutive alveolar clefts (43 patients) were identified as having undergone ABG and satisfied all the other inclusion criteria. Of these, 29 underwent first time ABG and 26 underwent redo ABG. The mean graft height and graft thickness recorded for all clefts was 2.2 and 2.0, respectively.

Conclusions

Early results evaluating the efficacy of ABG using DBX, rhBMP-2, and FDBC show feasibility in regard to both graft height and thickness when using a maxillary computed tomography scan to measure the bone graft take. These results suggest that DBX, rhBMP-2, and FDBC may act as a versatile bone graft material in cleft care, although further studies are needed to determine long-term outcomes.

Revisiting Recent Tissue Engineering Technologies in Alveolar Cleft Reconstruction

Tissue engineering and regenerative medicine have received significant attention in treating degenerative disorders and presented unique opportunities for researchers. The latest research on tissue engineering and regenerative medicine to reconstruct the alveolar cleft has been reviewed in this study. Three approaches have been used to reconstruct alveolar cleft: Studies that used only stem cells or biomaterials and studies that reconstructed alveolar defects by tissue engineering using a combination of stem cells and biomaterials. Stem cells, biomaterials, and tissue-engineered constructs have shown promising results in the reconstruction of alveolar defects. However, some contrary issues, including stem cell durability and scaffold stability, were also observed. It seems that more prospective and comprehensive studies should be conducted to fully clarify the exact dimensions of the stem cells and tissue engineering reconstruction method in the therapy of alveolar cleft.

Bioglass 45S5, a relevant alternative to autogenous harvesting for secondary alveolar bone grafts in clefts? Retrospective study of one hundred surgeries

The secondary alveolar bone grafting (SABG) step restores the continuity of the alveolar bone necessary for dentition. Faced with the complications of autografts, synthetic biomaterials such as Bioglass (BG) 45S5 have been proposed. The objective was to evaluate the success rate of SABG with the addition of BG 45S5 and to highlight the prognostic factors. Patients who underwent operation between 2015 and 2021 and had follow-up cone-beam computed tomography (CBCT) were analyzed. Multivariate analysis was performed to determine factors influencing radiographic success. A total of 102 SABG were analyzed. They were unilateral total cleft lip and palate (49, 48.0%). The mean age at surgery was 9.32 ± 3.09 years. Surgeries were performed mainly outside a syndromic context and without a family history after orthodontic preparation. The radiographic success rate at 1 year was 80.4%. Mixed dentition stage (odds ratio [OR] = 7.3, p = 0.024), absence of syndromic context (OR = 20.7, p = 0.024) and female sex (OR = 4.88, p = 0.021) were factors predictive of surgical success. The use of BG 45S5 instead of autograft is relevant for SABG, with a 1-year success rate of over 80%. The stage of mixed dentition, the absence of syndromic context, and female sex were factors for good prognosis.

Effect of adjuvant autologous platelet concentrates on secondary repair of alveolar clefts: A systematic review and meta-analysis

OBJECTIVE

To review the existing evidence on the adjuvant use of autologous platelet concentrates (APCs) with iliac crest bone graft (ICBG) in the reconstruction of the secondary alveolar cleft.

METHODS

Electronic databases were searched systematically until November 2022. Clinical trials comparing the three-dimensional radiological outcomes of patients who underwent secondary alveolar bone grafting (SABG) with ICBG and APCs to those with ICBG alone and the radiological outcomes assessed 6 months after surgery were included. Two authors performed the study selection and the assessment of the risk of bias. Meta-analysis was performed using the random-effects model to determine the risk ratio (RR) for developing wound dehiscence and the mean difference (MD) with a 95% confidence interval (CI) for the percentage of newly formed bone.

RESULTS

Nine studies (seven RCT and two CCT) were included with a low to high risk of bias. At the 6-month follow-up, the study group revealed insignificant results regarding the percentage of newly formed bone (MD = 6.49; 95% CI: -0.97, 13.94; p = .09; χ2  = 0.01; I2  = 71%). In addition, the overall risk of developing wound dehiscence was lower in the study group (RR = 0.34; 95% CI: 0.15, 0.78; p = .01; χ2  = 0.67; I2  = 0%).

CONCLUSION

Currently, there is insufficient evidence to support the adjuvant use of APCs with ICBG on enhanced bone regeneration following secondary alveolar bone grafting. However, combining ICBG and APCs might be beneficial in reducing the risk of developing wound dehiscence.

Radiographic Assessment of Different Autogenous Bone Grafts in the Alveolar Cleft: A Retrospective Longitudinal Study

Objectives

To assess feasibility and maintenance of bone after alveolar cleft reconstructions using graft from iliac crest and mandibular symphysis.

Methods

51 alveolar clefts grafted with iliac crest and 51 ones grafted with mandibular symphysis bones were selected from patients aged between 7 and 12 years. At three (T1) and 12 months (T2) after surgeries, periapical radiographs were performed to measure the height of the grafted bone based on the modified Bergland scale. Chi-square and Mann-Whitney-Wilcoxon tests compared differences between T1 and T2 according to each bone graft.

Results

From the clefts grafted with mandibular symphysis bone, 47 were classified as type I (92.5%) and 04 as type II (7.84%) at T1. At T2, 36 were classified as type II (25.49%) and 02 as type III (3.92%). In the analysis of the clefts grafted with iliac crest at T1, 48 were classified as type I (94.11%) and three as type II (5.88%). At T2, 37 classifieds as type I (72.54%), 12 as type II (23.52%) and two as type III (3.92%). There was no statistically significant difference between treatments.

Conclusions

It was concluded that iliac crest and mandibular symphysis are adequate areas from which bone grafts can be obtained for reconstruction of alveolar cleft.

Current State of Clinical Trials Regarding Alveolar Bone Grafting

Alveolar ridge defects develop because of surgery, trauma, infection, or congenital malformations. Alveolar ridge defects can be resolved using an osseous replacement. The primary outcomes of osseous replacement are the maintenance of contour; the elimination of dead space, the reduction of postoperative infection; and the increase in bony and soft tissue healing. Recent research shows promising developments in dental bone grafts. This review presents the results of several clinical trials and provides updates on current alveolar bone grafting.

In May 2023, we searched Clinicaltrials.gov for interventional clinical trials related to alveolar bone grafting. A total of 66 clinical trials were included using Boolean Operators AND, OR, NOT we used the "advanced search" option with the search terms [Alveolar Bone Grafting] OR [Ridge Preservation] OR [Dental Bone Grafting] OR [Ridge Augmentation]. Reviewed publications are summarized.

28 out of the 66 trials were successfully completed. None of the trials had offered an invitation to enroll, and only one was terminated. Autograft was the most prevalent kind of grafting, at 28 out of 66, more than twice as prevalent as allograft, which ranked second at 12 out of 66.

this study shows a lack of variety in location, low results provided, and low clinical trials regarding bone rejection. The focus of published trials was mainly on cleft palate rehabilitation using secondary alveolar bone grafting, and the usage of L-prf, rh-FGF-2, rhBMP2, and hyaluronic acid in association with alveolar bone grafting showed remarkable results concerning bone's osteoconduction, osteoinduction, and osteogenesis.

Updates in Cleft Care

Cleft lip and/or palate is a congenital malformation with a wide range of presentations, and its effective treatment necessitates sustained, comprehensive care across an affected child's life. Early diagnosis, ideally through prenatal imaging or immediately postbirth, is paramount. Access to longitudinal care and long-term follow-up with a multidisciplinary approach, led by the recommendations of the American Cleft Palate Association, is the best way to ensure optimal outcomes. Multiple specialties including plastic surgery, otolaryngology, speech therapy, orthodontists, psychologists, and audiologists all may be indicated in the care of the child. Primary repair of the lip, nose, and palate are generally conducted during infancy. Postoperative care demands meticulous oversight to detect potential complications. If necessary, revisional surgeries should be performed before the child begin primary school. As the child matures, secondary procedures like alveolar bone grafting and orthognathic surgery may be requisite. The landscape of cleft care has undergone significant transformation since early surgical correction, with treatment plans now tailored to the specific type and severity of the cleft. The purpose of this text is to outline the current standards of care in children born with cleft lip and/or palate and to highlight ongoing advancements in the field.

Treatment of critical bone defects using calcium phosphate cement and mesoporous bioactive glass providing spatiotemporal drug delivery

Calcium phosphate cements (CPC) are currently widely used bone replacement materials with excellent bioactivity, but have considerable disadvantages like slow degradation. For critical-sized defects, however, an improved degradation is essential to match the tissue regeneration, especially in younger patients who are still growing. We demonstrate that a combination of CPC with mesoporous bioactive glass (MBG) particles led to an enhanced degradation in vitro and in a critical alveolar cleft defect in rats. Additionally, to support new bone formation the MBG was functionalized with hypoxia conditioned medium (HCM) derived from rat bone marrow stromal cells. HCM-functionalized scaffolds showed an improved cell proliferation and the highest formation of new bone volume. This highly flexible material system together with the drug delivery capacity is adaptable to patient specific needs and has great potential for clinical translation.

Bilayer scaffolds/membranes for bone tissue engineering applications: A systematic review

OBJECTIVE

This systematic review evaluates the purpose, materials, physio-mechanical, and biological effects of bilayer scaffolds/membranes used for bone tissue engineering applications.

METHODS

A comprehensive electronic search of English-language literature from 2012 to October 2022 was conducted in PubMed, Scopus, ScienceDirect, and Google Scholar online databases according to the PRISMA 2020 guidelines. The quality of animal studies was evaluated through the SYRCLE's risk of bias tool.

RESULTS

A total of 77 studies were sought for retrieval, and 39 studies met the inclusion criteria. According to the synthesis results, most bilayers had a dense barrier layer that prevented connective tissue penetration and a loose osteogenic layer that supported cell migration and osteogenesis. PLGA, PCL, and chitosan were the most common polymers in the barrier layers, while the most utilized polymers in osteogenic layers were PLGA and gelatin. Electrospinning and solvent casting were the most common fabrication methods to design the bilayer structures. Many studies reported higher biological results for bilayers compared to their single layers. Also, fabricated bilayers' in vitro osteogenesis and in vivo new bone formation were significantly superior or at least comparable to the frequently used commercial membranes.

CONCLUSION

1) Bilayers with two distinct layers and different materials, porosities, mechanical properties, and biological behavior can significantly improve heterogeneous bone regeneration; 2) the addition of ceramics and/or drugs to the osteogenic layer enhances the osteogenic properties of the bilayers; 3) fabrication method and pore size of the layers play an important role in determining the mechanical and biological behavior of them.

Biomolecular Mechanisms and Case Series Study of Socket Preservation with Tooth Grafts

The purpose of this research was to assess the effectiveness of an innovative medical device capable of extracting tooth graft materials directly from the patient's own teeth. Twenty consecutive tooth grafting procedures were conducted, with an average follow-up period of 18 months.

METHODS

Twenty patients requiring tooth extraction underwent socket preservation utilizing the extracted tooth as the grafting material.

RESULTS

After a 4-month healing period, the defects were significantly filled with newly formed hard tissue. Subsequently, bone biopsies were performed during dental implant placement to evaluate histological outcomes. The tissue exhibited a similar density to medium-density bone, displaying a homogeneous and uniform appearance without any visible signs of inflammation. The post-operative healing phase was free from infective complications or indications of graft particles within the regenerated bone structure. The histomorphometric analyses revealed the following results: bone total volume, BV% 52.6 ± 13.09, vital bone VB% 40.39 ± 15.86, residual graft % 12.20 ± 12.34.

CONCLUSION

The study demonstrated positive bony healing in guided regenerative surgery procedures using autologous tooth grafts. However, further research with an extended follow-up period is necessary to thoroughly assess the potential of demineralized dentin autografts.

Effectiveness of Autogenous Chin Bone Graft in Reconstructive Surgery of Cleft Patients: A Systematic Review With Meta-Analysis and Algorithm of Treatment

PURPOSE

Bone grafting is fundamental in the treatment of cleft patients, and several grafting materials have been used for this purpose. The objective of this study is to evaluate the effectiveness of autogenous bone graft from the chin in the reconstruction of cleft alveolus.

METHODS

Searches were performed in six databases (PubMed, Scopus, Cochrane, LILACS, Embase, and Google Scholar) by two researchers individually until July 2022. This study was registered in the International Prospective Register of Systematic Reviews (CRD42021267954) and conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The predictor variable is reconstruction technique, grouped into three levels: autogenous genial grafts, other endochondral autogenous grafts, and bio- or tissue-engineered materials. The outcome variables were alveolar cleft healing rate and bone height. The secondary variables were complications that included infections, necrosis, paresthesia, and dehiscence. Data analysis included the risk of bias and assessment of the certainty of evidence by the risk of bias in nonrandomized studies of interventions and grading of recommendations, assessment, development, and evaluation tools, respectively. The meta-analysis was performed with heterogeneity based on random effects of I² and 95% confidence.

RESULTS

In the initial search, 4,833 articles were found, and 10 of them were included in this systematic review. The included studies were from six countries on three different continents, with a sample of 692 patients. It was observed that the chin bone graft (214 patients) when compared to the endochondral bone graft (386 patients) reduced by 0.42 [confidence interval 95% = 0.18, 0.95] times the prevalence of bone resorption (P = .040 and I² = 70%) analyzed in radiographic images. Two studies evaluated the bone filling through computed tomography, and there was no statistically significant difference between the groups (P = .340, I² = 0%). Only two studies had a low risk of bias.

CONCLUSION

Based on a low certainty of evidence, the chin autogenous bone graft proved to be similar to the endochondral graft in the reconstruction of the cleft alveolar; however, the limited number of studies with high heterogeneity and an uncertain risk of bias decreased the strength of the results found in this systematic review. New controlled primary studies should be carried out with the purpose of safely determining the effectiveness of chin bone grafts for the reconstruction of cleft alveolar.

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.

Outcomes of permanent canines on the cleft side after secondary alveolar grafting using different materials in complete unilateral cleft lip and palate

The prevalence of impaction of the permanent canine on the cleft side (PCCS) ranges from 12-35% after alveolar bone grafting (ABG). PCCSs usually develop above other permanent teeth in the alveolar process, gradually becoming vertical until they reach the occlusal plane. The type of cleft, hypodontia of lateral incisor on the cleft side, slower PCCS root development, and genetic factors are predictors of impaction and/or its ectopic eruption. To compare the behavior of PCCS in individuals with complete unilateral cleft lip and palate (UCLP) subjected to secondary alveolar grafting (SAG) with different materials. This retrospective longitudinal study analyzed 120 individuals undergoing SAG with iliac crest bone, rhBMP-2, and mandibular symphysis. The individuals were selected at a single center and equally divided into three groups. Panoramic radiographs were analyzed by the Dolphin Imaging 11.95 software to measure PCCS angulation and PCCS height from the occlusal plane at two different timepoints. No statistical significance was found between grafting materials (P=0.416). At T1, the PCCS height from the occlusal plane was greater for rhBMP-2 and mandibular symphysis compared to iliac crest bone. The lateral incisor on the cleft side was not related to success or lack of eruption of PCCS (P=0.870). Impaction rates of PCCS were similar for the materials studied. Absence of the lateral incisor on the cleft side did not prevent spontaneous eruption of PCCSs.

Appropriate pore size for bone formation potential of porous collagen type I-based recombinant peptide

Introduction

In this study, we developed porous medium cross-linked recombinant collagen peptide (mRCP) with two different ranges of interconnected pore sizes, Small-mRCP (S-mRCP) with a range of 100–300 μm and Large-mRCP (L-mRCP) with a range of 200–500 μm, to compare the effect of pore size on bone regeneration in a calvarial bone defect.

Methods

Calvarial bone defects were created in Sprague–Dawley rats through a surgical procedure. The rats were divided into 2 groups: S-mRCP implanted group and L-mRCP implanted group. The newly formed bone volume and bone mineral density (BMD) was evaluated by micro-computed tomography (micro-CT) immediately after implantation and at 1, 2, 3, and 4 weeks after implantation. In addition, histological analyses were carried out with hematoxylin and eosin (H&E) staining at 4 weeks after implantation to measure the newly formed bone area between each group in the entire defect, as well as the central side, the two peripheral sides (right and left), the periosteal (top) side and the dura matter (bottom) side of the defect.

Results

Micro-CT analysis showed no significant differences in the amount of bone volume between the S-mRCP and L-mRCP implanted groups at 1, 2, 3 and 4 weeks after implantation. BMD was equivalent to that of the adjacent native calvaria bone at 4 weeks after implantation. H&E images showed that the newly formed bone area in the entire defect was significantly larger in the S-mRCP implanted group than in the L-mRCP implanted group. Furthermore, the amount of newly formed bone area in all sides of the defect was significantly more in the S-mRCP implanted group than in the L-mRCP implanted group.

Conclusion

These results indicate that the smaller pore size range of 100–300 μm is appropriate for mRCP in bone regeneration.

•

This study confirmed the regenerative potential of mRCP as novel bone substitute.

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mRCP with 2 different interconnected pores sizes have been developed.

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The smaller pore size range of 100–300 μm was optimal for calvarial bone regeneration.

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The slower absorption rate of smaller pore size mRCP influenced its effectiveness.

The strategy of composite grafting with BMP2-Loaded calcium phosphate cements and autogenous bone for alveolar cleft reconstruction

Purpose: To remedy the drawbacks of traditional autogenous bone harvesting in alveolar bone grafting (ABG), a novel strategy of composite grafting with BMP2-loaded calcium phosphate cements (BMP2-CPC) and autogenous bone harvested by minimally invasive technique was developed and evaluated for its bone-repairing efficacy.

Materials and methods: A chart review was conducted for 19 patients with unilateral alveolar clefts who underwent secondary ABG from 2017 to 2020. Of the enrolled patients, 9 patients underwent grafting with autogenous bone harvested by traditional trap door technique (group I), and 10 patients underwent grafting with the composite graft comprising BMP2-CPC and autogenous bone harvested by minimally invasive technique at a ratio of 1:1 by volume (group II). The clinical performance of the composite graft was comprehensively evaluated in terms of clinical, radiographic and histological perspectives.

Results: The present results demonstrated that the composite graft exhibited satisfactory bone-repairing efficacy comparable to that of the autogenous bone graft on the premise of lower amount of harvested bone. The post-surgical resorption of bone volume and vertical height of grafted area was significantly slower in group II. The favourable resorption performance of BMP2-CPC contributed to preserving the post-surgical bony contour reconstructed with the composite graft.

Conclusion: The composite graft comprising BMP2-CPC and autogenous bone harvested by minimally invasive technique was demonstrated to be an eligible alternative for application in ABG, especially for its improved resorption performance in preserving post-surgical bony contour.

Secondary Alveolar Bone Grafting in Patients with Unilateral and Bilateral Complete Cleft Lip and Palate: A Single-Institution Outcomes Evaluation Using Three-Dimensional Cone Beam Computed Tomography

BACKGROUND

Secondary alveolar bone grafting of autologous bone from the iliac crest is a widely accepted modality for repair of residual alveolar cleft in patients with mixed dentition with previously repaired complete cleft lip and palate. There remains debate regarding surgical timing and preoperative, perioperative, and postoperative management of these cases.

METHODS

This retrospective study reviewed patient demographic information in addition to preoperative, perioperative, and postoperative course to evaluate how patient and practice factors impact graft outcomes as assessed by three-dimensional cone beam computed tomographic evaluation at the 6-month postoperative visit.

RESULTS

On univariate analysis, age at operation older than 9 years, history of oronasal fistula, history of cleft lip or palate revision, and history of international adoption were all found to significantly increase likelihood of graft failure (p < 0.05). On multivariate analysis, age older than 9 years was found to be the single most significant predictor of graft failure (p < 0.05). There was no significant difference in graft outcomes between patients with unilateral or bilateral cleft lip and palate, and no single variable was found to significantly correlate to increased complication rates. The graft success rate overall of the authors' practice was 86.2 percent, with a complication rate of 7.7 percent.

CONCLUSIONS

Secondary alveolar bone grafting is an integral part of the cleft lip and palate surgical treatment series; this study identified several outcome predictors for both graft failure and adverse events, the most significant of which was age at operation. Although the mixed dentition phase often extends to 12 years of age, it is recommended that bone grafting be performed before 9 years of age to optimize outcomes.

CLINICAL QUESTIONS/LEVEL OF EVIDENCE

Risk, III.

Use of Polyesters in Fused Deposition Modeling for Biomedical Applications

In recent years, 3D printing techniques experienced a growing interest in several sectors, including the biomedical one. Their main advantage resides in the possibility to obtain complex and personalized structures in a cost-effective way impossible to achieve with traditional production methods. This is especially true for Fused Deposition Modeling (FDM), one of the most diffused 3D printing methods. The easy customization of the final products' geometry, composition and physico-chemical properties is particularly interesting for the increasingly personalized approach adopted in modern medicine. Thermoplastic polymers are the preferred choice for FDM applications, and a wide selection of biocompatible and biodegradable materials is available to this aim. Moreover, these polymers can also be easily modified before and after printing to better suit the body environment and the mechanical properties of biological tissues. This review focuses on the use of thermoplastic aliphatic polyesters for FDM applications in the biomedical field. In detail, the use of poly(ε-caprolactone), poly(lactic acid), poly(lactic-co-glycolic acid), poly(hydroxyalkanoate)s, thermo-plastic poly(ester urethane)s and their blends has been thoroughly surveyed, with particular attention to their main features, applicability and workability. The state-of-the-art is presented and current challenges in integrating the additive manufacturing technology in the medical practice are discussed. This article is protected by copyright. All rights reserved.

Does the incorporation of strontium into calcium phosphate improve bone repair? A meta-analysis

Background

The application of calcium phosphate (CaP)-based bone substitutes plays an important role in periodontal regeneration, implant dentistry and alveolar bone reconstruction. The incorporation of strontium (Sr) into CaP-based bone substitutes appears to improve their biological properties, but the reported in vivo bone repair performance is inconsistent among studies. Herein, we conducted a systematic review and meta-analysis to investigate the in vivo performance of Sr-doped materials.

Methods

We searched PubMed, EMBASE (via OVIDSP), and reference lists to identify relevant animal studies. The search, study selection, and data extraction were performed independently by two investigators. Meta-analyses and sub-group analyses were conducted using Revman version 5.4.1. The heterogeneity between studies were assessed by I². Publication bias was investigated through a funnel plot.

Results

Thirty-five studies were finally enrolled, of which 16 articles that reported on new bone formation (NBF) were included in the meta-analysis, covering 31 comparisons and 445 defects. The overall effect for NBF was 2.25 (95% CI 1.61–2.90, p < 0.00001, I² = 80%). Eight comparisons from 6 studies reported the outcomes of bone volume/tissue volume (BV/TV), with an overall effect of 1.42 (95% CI 0.65–2.18, p = 0.0003, I² = 75%). Fourteen comparisons reported on the material remaining (RM), with the overall effect being -2.26 (95% CI − 4.02 to − 0.50, p = 0.0009, I² = 86%).

Conclusions

Our study revealed that Sr-doped calcium phosphate bone substitutes improved in vivo performance of bone repair. However, more studies are also recommended to further verify this conclusion.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02092-7.

Clinical Application of Stem Cell Therapy in Reconstructing Maxillary Cleft Alveolar Bone Defects: A Systematic Review of Randomized Clinical Trials

An alveolar cleft is the most common congenital bone defect. This systematic review aimed to investigate the use of stem cells for alveolar cleft repair and summarize the outcomes of clinical research studies. The electronic databases PubMed, Scopus, Web of Sciences, and Google Scholar were utilized to search the literature for relevant studies after administering specific inclusion and exclusion criteria. The search included articles that were published from 2011 to 2021 and specific keywords were used in the databases. The search was completed by two independent reviewers following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.Only four studies satisfied both the inclusion and exclusion criteria and were included in this systematic review. These studies investigated different aspects of bone reconstruction in the maxillary alveolar bone by stem cells, including cell types, clinical applications, biomaterial scaffolds, and follow-up period. The accumulated evidence in this systematic review is limited and insufficient to support the role of stem cell use in bone regeneration of maxillary alveolar bone defects. The outcome of using stem cells was studied only in 57 subjects from the four included studies. Although the noninvasive methods of isolating stem cells make them attractive resources for bone regeneration, more research is required in order to standardize and investigate stem cell therapy. This should be done beforehand in adults in less invasive procedures such as bone defect repair in dentistry prior to considering this type of therapy in this vulnerable patient population.

Efficacy of regenerative medicine for alveolar cleft reconstruction: A systematic review and meta-analysis

Objective:

Objective: To analyze the efficacy and complications of regenerative medicine compared to autogenous bone graft for alveolar cleft reconstruction.

Method:

Method: Electronic search was done in PubMed, Scopus, Embase and Cochrane database for studies published until May 2021. No limitations were considered for the type of the included studies. The risk of bias (ROB) of the studies was assessed using the Cochrane Collaborations and NIH quality assessment tool. Meta-analyses were performed to assess the difference in the amount of bone formation and rate of complications. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used for analyzing the level of the evidence.

Results:

Results: Among a total of 42 included studies, 21 studies used growth factors, 16 studies delivered cells, and five studies used biomaterials for bone regeneration of the alveolar cleft. Results showed no significant difference in the amount of bone formation between bone morphogenic protein-2 and iliac graft treated patients after six months (P=0.44) and 12 months (P=0.17) follow-up. Besides, higher swelling (OR=9.46,P<0.01) and less infection (OR=0.19,P=0.01) observed in BMP treated patients. Using stem cells can reduce the post-treatment pain (OR=0.04,P=0.01) but it has no significant impact on other complications (P>0.05). Using tissue engineering methods reduced the operation time (SD=1.06,P<0.01). GRADE assessment showed that results regarding the amount of bone formation volume after six and 12 months have low level of evidence.

Conclusion:

Conclusion: Tissue engineering methods can provide a comparable amount of bone formation as of the autogenous graft and reduce some of the complications, operation time and hospitalization duration.

Experimental study on the biocompatibility and osteogenesis induction ability of PLLA/DDM scaffolds

To investigate the characterization and function of a novel porous osteogenic material (PLLA / DDM) containing polylactic acid and demineralized dentin matrix. The surface morphology and composition of the material were observed by SEM and EDS. The physical characteristics of the material were detected by roughness and water contact angle analyses. The rate of weight loss and change in the pH value of the material were observed by scaffold degradation experiments. Four types of material were investigated: polylactic acid (PLLA) scaffold, demineralized dentin matrix (DDM) particles, PLLA/DDM scaffold and a blank control. The osteogenic effect and osteogenic characteristics of the new materials were explored through in vivo and in vitro osteogenic experiments. SEM analysis showed that DDM powder was uniformly distributed in the polylactic acid scaffold, and the water contact angle revealed that the water absorption of the porous scaffold was improved after the addition of DDM powder. The EDS results showed that the peak values of calcium and phosphorus were obviously increased after the addition of DDM powder, and the porosity test showed that the scaffold had higher porosity after the addition of DDM powder. Scaffold degradation experiments revealed that the scaffold gradually degraded with increasing time, and its pH value slightly increased. The results of cell culture and animal model experiments showed that the porous PLLA/DDM scaffold had good bio-compatibility and promoted cell proliferation and differentiation. In histological and micro-CT evaluations, the material showed good bio-compatibility, biodegradability and bone conductivity with host bone tissue in vivo. PLLA / DDM hybrid showed better performance than PLLA or DDM. The biocompatibility and cell growth promoting properties were stronger than those of single material.

Effectiveness of rhBMP-2 versus iliac autogenous bone graft in reconstructive surgery of cleft patients: an umbrella review

The objective of this umbrella review was to determine the effectiveness of rhBMP-2 in the reconstructive surgery of cleft patients through an evaluation of bone filling and volume of newly formed bone in the cleft area. A systematic search was carried out in PubMed/ Medline, Scopus, Cochrane Database of Abstracts of Reviews of Effects (DARE), Latin American and Caribbean Health Sciences Literature (LILACS), and the System for Information on Grey Literature in Europe (SIGLE) via Open Grey, until June 2020. Risk of bias was assessed using the ROBIS tool. A total of 2739 articles were identified and, based on the inclusion and exclusion criteria, six were included for final evaluation. The bone filling rate was 74.23% in the rhBMP-2 group and 72.38% in the autogenous group. Regarding the risk of bias, none of the articles had a low risk, four had an uncertain risk, and two a high risk. The results of this umbrella review show that the studies had high and uncertain risks of bias, and high heterogeneity. There was a lack of evidence regarding the possible complications offered by this therapy. The recommendation to use BMP-2 for alveolar cleft reconstruction, especially in a paediatric population, should be viewed with caution. New primary studies are needed to assess this variable and safely determine the use of rhBMP-2 in reconstructive surgery for cleft patients.

Transforming the Degradation Rate of β-tricalcium Phosphate Bone Replacement Using 3-Dimensional Printing

BACKGROUND

β-Tricalcium phosphate (β-TCP) is one of the most common synthetic bone grafting materials utilized in craniofacial reconstruction; however, it is limited by a slow degradation rate. The aim of this study was to leverage 3-dimensional (3D) printing in an effort to accelerate the degradation kinetics of β-TCP.

METHODS

Twenty-two 1-month-old New Zealand white rabbits underwent creation of calvarial and alveolar defects, repaired with 3D-printed β-TCP scaffolds coated with 1000 μM of osteogenic agent dipyridamole. Rabbits were euthanized after 2, 6, and 18 months after surgical intervention. Bone regeneration, scaffold degradation, and bone mechanical properties were quantified.

RESULTS

Histological analysis confirmed the generation of vascularized and organized bone. Microcomputed tomography analysis from 2 to 18 months demonstrated decreased scaffold volume within calvarial (23.6% ± 2.5%, 5.1% ± 2.2%; P < 0.001) and alveolar (21.5% ± 2.2%, 0.2% ± 1.9%; P < 0.001) defects, with degradation rates of 54.6%/year and 90.5%/year, respectively. Scaffold-inducted bone generation within the defect was volumetrically similar to native bone in the calvarium (55.7% ± 6.9% vs 46.7% ± 6.8%; P = 0.064) and alveolus (31.4% ± 7.1% vs 33.8% ± 3.7%; P = 0.337). Mechanical properties between regenerated and native bone were similar.

CONCLUSIONS

Our study demonstrates an improved degradation profile and replacement of absorbed β-TCP with vascularized, organized bone through 3D printing and addition of an osteogenic agent. This novel additive manufacturing and tissue engineering protocol has implications to the future of craniofacial skeletal reconstruction as a safe and efficacious bone tissue engineering method.

FDA-approved bone grafts and bone graft substitute devices in bone regeneration

To induce bone regeneration there is a complex cascade of growth factors. Growth factors such as recombinant BMP-2, BMP-7, and PDGF are FDA-approved therapies in bone regeneration. Although, BMP shows promising results as being an alternative to autograft, it also has its own downfalls. BMP-2 has many adverse effects such as inflammatory complications such as massive soft-tissue swelling that can compromise a patient's airway, ectopic bone formation, and tumor formation. BMP-2 may also be advantageous for patients not willing to give up smoking as it shows bone regeneration success with smokers. BMP-7 is no longer an option for bone regeneration as it has withdrawn off the market. PDGF-BB grafts in studies have shown PDGF had similar fusion rates to autologous grafts and fewer adverse effects. There is also an FDA-approved bioactive molecule for bone regeneration, a peptide P-15. P-15 was found to be effective, safe, and have similar outcomes to autograft at 2 years post-op for cervical radiculopathy due to cervical degenerative disc disease. Growth factors and bioactive molecules show some promising results in bone regeneration, although more research is needed to avoid their adverse effects and learn about the long-term effects of these therapies. There is a need of a bone regeneration method of similar quality of an autograft that is osteoconductive, osteoinductive, and osteogenic. This review covers all FDA-approved bone regeneration therapies such as the "gold standard" autografts, allografts, synthetic bone grafts, and the newer growth factors/bioactive molecules. It also covers international bone grafts not yet approved in the United States and upcoming technologies in bone grafts.

The Challenge of 3D Bioprinting of Composite Natural Polymers PLA/Bioglass: Trends and Benefits in Cleft Palate Surgery

Cleft lip and palate is the fourth most common congenital malformation. Its prevalence is about 1 in 750 to 1 in 2000 live births. The consequences of this malformation are major: maxillary growth deficit, unaesthetic appearance, phonation disorders, difficulty in eating, and psycho-social disorders. Cleft palate repair establishes the division between the oral and nasal cavities. The alveolar bone graft is a key step. Different sites of autogenous bone harvesting are used, the most common being the iliac crest. Nevertheless, the large number of complications associated with harvesting has led to the use of substitute biomaterials. Bioactive glasses, discovered in 1969, are a group of synthetic silica-based materials with bone-bonding properties. Although 45S5 granular composition is commonly used in bone surgery to repair critical defects, it is only rarely used in the repair of cleft palates because this galenic form is only moderately adapted. However, advances in bone tissue engineering allow the shaping of three-dimensional scaffolds, which support colonization by host cells. Recent advances in computer-aided design/computer-aided manufacturing (CAD/CAM) have even led to the 3D printing of scaffolds combining 45S5 bioglass with a natural and biocompatible poly-lactic acid matrix. The shape of the parts is customized and adapted to the particular shape of the critical bone defects. The objective of this literature review is to highlight the particularities of alveolar defects subsequent to facial clefts, then to detail the characteristics of the materials and technologies used to elaborate 3D matrices by bioprinting. Finally, we will explore research directions regarding their use in reconstructive surgery of cleft palates.

Skeletal and Dental Habilitation of Residual Alveolar and Maxillary Clefts

ABSTRACT

Management of residual clefts of the alveolus and maxilla requires the coordinated effort of multiple members of the craniofacial team including surgeon, orthodontist, and when teeth are hypoplastic or absent, the prosthodontist to achieve complete habilitation. Such cooperation among specialists begins early in the patient's life and continues through completion of care.Although numerous publications on this topic exist, few present definitive multidisciplinary reconstructive outcomes with longterm results. In this review paper, the authors present our comprehensive, multidisciplinary protocols, experience, and techniques as they have evolved with over 35 years of practice at our Craniofacial Center.Details of our updated protocols for each intervention and procedure, including our current thoughts on appropriate timing, follow up and advantages from the incorporation of current technologies are discussed. Close cooperation among specialists at all stages of care, the use of evolving technology, and adherence to, and modification where indicated, of time honored team protocols enables us to consistently achieve successful functional and esthetic outcomes, while minimizing complications.

[Influence of different sintering temperatures on mesoporous structure and ectopic osteogenesis of biphasic calcium phosphate ceramic granule materials]

Objective

To detect the difference in the osteogenesis ability of biphasic calcium phosphate (BCP) ceramic granular materials with different mesoporous diameters prepared at different sintering temperatures through in vivo and in vitro experiments, so as to provide evidence for screening BCP materials with better clinical application parameters.

Methods

Three kinds of BCP (materials 1, 2, 3) were prepared by mixing hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) at a ratio of 8∶2 and sintered at 1 050, 1 150, and 1 250℃ for 3 hours, respectively. The internal porosity and the diameter, volume, and area of the mesopore were measured by Brunauer-Emmett-Teller test (BET); the composition of the material was evaluated by X-ray diffraction (XRD); the microscopic surface morphology of the material was observed by scanning electron microscopy (SEM). The 3rd generation bone marrow mesenchymal stem cells (BMSCs) from Sprague-Dawley rats were co-cultured with the materials 1, 2, and 3 for 7 days in vitro respectively (groups A, B, and C), and the cells adhesion on the materials was observed by SEM and phalloidine staining, respectively. Cell proliferation activity was measured by cell counting kit 8 method. In vivo, 9 muscle bags were made in dorsal muscles of 9 beagles, respectively. The muscle bags were randomly divided into 3 groups (3 per beagle in each group) and materials 1, 2, and 3 were placed into the muscle bags of groups A, B, and C, respectively. After 1, 2, and 3 months of operation, 3 beagles were anesthetized and the samples were stained with HE, Masson, and Safranin, and the bone formation area ratio in the BCP gap was calculated. Real-time fluorescence quantitative PCR (qRT-PCR) was performed to detect the expressions of bone-related genes [including alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OC)].

Results

The BET test showed that with the increase of sintering temperature, the internal porosity of the particles did not change significantly, but the diameter, volume, and area of the mesopores gradually decreased. The XRD detection showed that the XRD waves of HA and β-TCP could be seen in all 3 kinds of materials; SEM showed that there were widely distributed macropores on the surface of 3 kinds of BCPs, and the interpores connected with the others. In vitro, BMSCs adhered and proliferated on the surfaces of 3 kinds of BCPs, and the cell biocompatibility of the materials in groups B and C was better than that in group A. In vivo, obvious osteoid tissue deposition could be observed in the intergranular space of 3 kinds of BCPs from 2 months after implantation. The bone formation area ratio of each group increased with time. The bone formation area ratio in group A was significantly higher than that in groups B and C at 2 and 3 months after implantation, and in group A than in group B at 1 month ( P<0.05). qRT-PCR showed that the expressions of osteogenic related genes peaked at 2 months in group A, and gradually increased with time in groups B and C. The relative expressions of ALP and OPN mRNAs in group A were significantly higher than those in groups B and C at 1 month after implantation, the relative expression of OC mRNA in group A was significantly higher than that in groups B and C at 2 months after operation, the relative expression of ALP mRNA in groups B and C and the relative expression of OPN mRNA in group B were significantly higher than those in group A, all showing significant differences ( P<0.05); there was no significant difference in the relative expression of each gene among the other groups at each time point ( P>0.05).

Conclusion

The mesoporous diameter of BCP decreases with the increase of sintering temperature. Different mesoporous diameters lead to different ectopic osteogenesis of BCP materials. BCP material with mesoporous diameter of 12.57 nm has better osteogenic ability which can activate the osteogenic gene earlier. The mesoporous diameter is expected to be an adjustable index for optimizing the osteogenic capacity of BCP materials.

Bone formation potential of collagen type I-based recombinant peptide particles in rat calvaria defects

Introduction

This study aimed to examine the bone-forming ability of medium-cross-linked recombinant collagen peptide (mRCP) particles developedbased on human collagen type I, contains an arginyl-glycyl-aspartic acid-rich motif, fabricated as bone filling material, compared to that of the autologous bone graft.

Methods

Calvarial bone defects were created in immunodeficient rats though a surgical procedure. The rats were divided into 2 groups: mRCP graft and tibia bone graft (bone graft). The bone formation potential of mRCP was evaluated by micro-computed tomography and hematoxylin-eosin staining at 1, 2, 3, and 4 weeks after surgery, and the data were analyzed and compared to those of the bone graft.

Results

The axial volume-rendered images demonstrated considerable bony bridging with the mRCP graft, but there was no significant difference in the bone volume and bone mineral density between the mRCP graft and bone graft at 4 weeks. The peripheral new bone density was significantly higher than the central new bone density and the bottom side score was significantly higher than the top side score at early stage in the regenerated bone within the bone defects.

Conclusion

These results indicate that mRCP has a high potential of recruiting osteogenic cells, comparable to that of autologous bone chips.

•

Bone formation potential of mRCP were comparable to that of autogenous bone.

•

mRCP particles exhibit high new bone formation potential in the calvaria defect.

•

Bone bridging was observed over the entire defect in mRCP graft at 4 weeks.

•

mRCP has a high potential of recruiting osteogenic cells comparable to bone graft.

Efficacy of Staged Oronasal Fistula Reconstruction and Improved Bone Graft Survival in Cleft Patients Undergoing Secondary Reconstruction

OBJECTIVE

To evaluate the efficacy of the senior author's technique of staged reconstruction in patients with recalcitrant oronasal fistulas.

DESIGN

A retrospective review of the Pediatric Plastic Surgery Cleft & Craniofacial Surgery Database of cases from September 2013 to December 2018 was conducted.

PATIENTS

A total of 31 patients who had previously undergone >1 surgical attempt to repair a fistula or patients who have failed >1 attempt at bone graft were included in this study. All patients were referrals from outside facilities.

MAIN OUTCOME MEASURES

Primary outcomes examined included fistula recurrence, infection rates, ability to proceed with second stage bone grafting after first stage fistula takedown and reconstruction, and bone graft loss.

RESULTS

Charts of 1053 patients were reviewed and 31 (2.94%) cases met inclusion criteria for this study. Nineteen (61.3%) of these patients proceeded with the second stage of reconstruction and 100% did not experience any graft loss. Seven patients who completed the first stage are undergoing orthodontic optimization prior to bone grafting. The remaining 5 are adult patients not interested in pursuing bone grafting. All 31 patients with recurrent and recalcitrant fistulas had successful fistula reconstruction with our approach, despite multiple previous failed reconstructions.

CONCLUSIONS

The 2-staged reconstructive approach described herein effectively resulted in resolution of prior recurrent recalcitrant fistulas and resulted in eventual bone grafting. By employing this technique, we report successful fistula repair and bone grafting in patients who had previously undergone multiple surgical reconstructions.

Innovative Molecular and Cellular Therapeutics in Cleft Palate Tissue Engineering

Clefts of the lip and/or palate are the most prevalent orofacial birth defects occurring in about 1:700 live human births worldwide. Early postnatal surgical interventions are extensive and staged to bring about optimal growth and fusion of palatal shelves. Severe cleft defects pose a challenge to correct with surgery alone, resulting in complications and sequelae requiring life-long, multidisciplinary care. Advances made in materials science innovation, including scaffold-based delivery systems for precision tissue engineering, now offer new avenues for stimulating bone formation at the site of surgical correction for palatal clefts. In this study, we review the present scientific literature on key developmental events that can go awry in palate development and the common surgical practices and challenges faced in correcting cleft defects. How key osteoinductive pathways implicated in palatogenesis inform the design and optimization of constructs for cleft palate correction is discussed within the context of translation to humans. Finally, we highlight new osteogenic agents and innovative delivery systems with the potential to be adopted in engineering-based therapeutic approaches for the correction of palatal defects. Impact statement Tissue-engineered scaffolds supplemented with osteogenic growth factors have attractive, largely unexplored possibilities to modulate molecular signaling networks relevant to driving palatogenesis in the context of congenital anomalies (e.g., cleft palate). Constructs that address this need may obviate current use of autologous bone grafts, thereby avoiding donor-site morbidity and other regenerative challenges in patients afflicted with palatal clefts. Combinations of biomaterials and drug delivery of diverse regenerative cues and biologics are currently transforming strategies exploited by engineers, scientists, and clinicians for palatal cleft repair.

Bone augmentation by replica-based bone formation

OBJECTIVE

The sources of iliac crest bone grafts are limited. Alternatives are evaluated due to the progress in biomaterial sciences. Synthetical hydroxyapatite (HA), ß-tricalcium phosphate (ß-TCP) or biphasic compounds, or even a mélange of HA and ß-TCP will replace bovine ceramics. The goal is maintenance of replica-based-bone formation (RBBF) for bone augmentation.

METHODS

2 female and 2 male patients between 41 and 73 years with 5 sinus elevations were evaluated. Sinus elevations with lateral fenestration, trapezoidal-muco-periosteal flaps and filling with micro-chambered beads (1.5 mm) was performed. A porcine-collagenous membrane and the refixated flap covered the defect. A biopsy program over 20 months was confirm confirm the maintenance of the newly formed bone.

RESULTS

A fast bone formation was pronounced. The biopsies revealed mature lamellar bone and full osseointegration of the ß-TCP implant. The biopsy after 20 months showed compact bone with osseointegration of minor rests of the ceramic implant. The defect revealed a mature bone stock already after 5 weeks.

SIGNIFICANCE

The introduction of the replica-based-bone formation (RBBF) around micro-chambered beads will change the paradigm of bone augmentation. The next step of the ongoing study has to redefine the interval for implant insertion. The clinical approach confirms the breakthrough to primary mature lamellar bone formation and will permit reduction of placement time for a dental implant.

Tissue engineering applications in otolaryngology-The state of translation

While tissue engineering holds significant potential to address current limitations in reconstructive surgery of the head and neck, few constructs have made their way into routine clinical use. In this review, we aim to appraise the state of head and neck tissue engineering over the past five years, with a specific focus on otologic, nasal, craniofacial bone, and laryngotracheal applications. A comprehensive scoping search of the PubMed database was performed and over 2000 article hits were returned with 290 articles included in the final review. These publications have addressed the hallmark characteristics of tissue engineering (cellular source, scaffold, and growth signaling) for head and neck anatomical sites. While there have been promising reports of effective tissue engineered interventions in small groups of human patients, the majority of research remains constrained to in vitro and in vivo studies aimed at furthering the understanding of the biological processes involved in tissue engineering. Further, differences in functional and cosmetic properties of the ear, nose, airway, and craniofacial bone affect the emphasis of investigation at each site. While otolaryngologists currently play a role in tissue engineering translational research, continued multidisciplinary efforts will likely be required to push the state of translation towards tissue-engineered constructs available for routine clinical use.

LEVEL OF EVIDENCE

NA.

Electrical Stimulation Decreases Dental Pulp Stem Cell Osteo-/Odontogenic Differentiation

Dental pulp stem cells (DPSCs) have great potential for use in tissue engineering (TE)-based dental treatments. Electrical stimulation (EStim) has been shown to influence cellular functions that could play an important role in the success of TE treatments. Despite many recent studies focused on DPSCs, few have investigated the effect EStim has on these cells. The aim of this research was to investigate the effects of direct current (DC) EStim on osteo-/odontogenic differentiation of DPSCs. To do so cells were isolated from male Sprague Dawley rats (7-8 weeks old), and phenotype characterization and multilineage differentiation analysis were conducted to verify their "stemness." Different voltages of DC EStim were administrated 1 h/day for 7 days, and the effect of EStim on DPSC osteo-/odontogenic differentiation was assessed by measuring calcium and collagen deposition, alkaline phosphatase (ALP) activity, and expression of osteo- and odontogenic marker genes at days 7 and 14 of culture. We found that while 10 and 50 mV/mm of EStim had no effect on cell number or metabolic activity, 100 mV/mm caused a significant reduction in cell number, and 150 mV/mm resulted in cell death. Despite increased gene expression of osteo-/odontogenic gene markers, Osteocalcin, RunX2, BSP, and DMP1, at day 7 in EStim treated cells, 50 mV/mm of EStim decreased collagen deposition and ALP activity at both time points, and calcium deposition was found to be lower at day 14. In conclusion, under the conditions tested, EStim appears to impair DPSC osteo-/odontogenic differentiation. Additional studies are needed to further characterize and understand the mechanisms involved in DPSC response to EStim, with an eye toward its potential use in TE-based dental treatments.

3D Printing of Bone Grafts for Cleft Alveolar Osteoplasty - In vivo Evaluation in a Preclinical Model

One of the most common hereditary craniofacial anomalies in humans are cleft lip and cleft alveolar bone with or without cleft palate. Current clinical practice, the augmentation of the persisting alveolar bone defect by using autologous bone grafts, has considerable disadvantages motivating to an intensive search for alternatives. We developed a novel therapy concept based on 3D printing of biodegradable calcium phosphate-based materials and integration of osteogenic cells allowing fabrication of patient-specific, tissue-engineered bone grafts. Objective of the present study was the in vivo evaluation of implants in a rat alveolar cleft model. Scaffolds were designed according to the defect's geometry with two different pore designs (60° and 30° rotated layer orientation) and produced by extrusion-based 3D plotting of a pasty calcium phosphate cement. The scaffolds filled into the artificial bone defect in the palate of adult Lewis rats, showing a good support. Half of the scaffolds were colonized with rat mesenchymal stromal cells (rMSC) prior to implantation. After 6 and 12 weeks, remaining defect width and bone formation were quantified histologically and by microCT. The results revealed excellent osteoconductive properties of the scaffolds, a significant influence of the pore geometry (60° > 30°), but no enhanced defect healing by pre-colonization with rMSC.

Outcomes of bone morphogenetic protein-2 and iliac cancellous bone transplantation on alveolar cleft bone grafting: A meta-analysis

BACKGROUND

To systematically evaluate the effect of bone morphogenetic protein-2 (BMP-2) and iliac cancellous bone graft (ICBG) on alveolar cleft bone grafting (ACBG) in cleft lip and palate.

METHOD

Online databases were searched for case-control studies related to the application of BMP-2 and ICBG in ACBG.

RESULT

Meta-analysis showed no significant statistical difference in the filling rate (OR = 4.1, 95% CI (0.06, 2.63)), the volume of bone graft area (OR=-0.42, 95% CI (-1.44, 0.60)), the height of bone graft area (OR = -21.38, 95% CI (-23.00, -19.76)), the density of bone graft area (OR = 0.43, 95% CI (-0.79, 1.64)), the failure rate of bone graft (OR = 0.02, 95% CI (-0.03, 0.06)), infection after operation, and the rate (OR = 0.20, 95% CI (0.05, 0.73)) and the incidence of postoperative oronasal fistula (OR = 4.1, 95% CI (0.06, 2.63)) between BMP-2 and ICBG in ACBG. However, there were obvious statistical differences in operative time (OR = -3.64, 95% CI (-7.35, 0.06)) and the length of hospital stay (OR = -1.97, 95% CI (-2.41, -1.53)).

CONCLUSION

The meta-analysis shows that there is no significant difference between BMP-2 and ICBG in filling rate, volume, density, failure rate, and the occurrence of oronasal fistula after ACBG. There were significant differences between BMP-2 and ICBG in the operation time and hospitalization time of ACBG. Compared with ICBG bone graft, BMP-2 has more advantages in ACBG such as remaining area height, postoperative infection rate, operative time, and length of hospital stay.

Extracellular Matrix Composition and Remodeling: Current Perspectives on Secondary Palate Formation, Cleft Lip/Palate, and Palatal Reconstruction

Craniofacial development comprises a complex process in humans in which failures or disturbances frequently lead to congenital anomalies. Cleft lip with/without palate (CL/P) is a common congenital anomaly that occurs due to variations in craniofacial development genes, and may occur as part of a syndrome, or more commonly in isolated forms (non-syndromic). The etiology of CL/P is multifactorial with genes, environmental factors, and their potential interactions contributing to the condition. Rehabilitation of CL/P patients requires a multidisciplinary team to perform the multiple surgical, dental, and psychological interventions required throughout the patient's life. Despite progress, lip/palatal reconstruction is still a major treatment challenge. Genetic mutations and polymorphisms in several genes, including extracellular matrix (ECM) genes, soluble factors, and enzymes responsible for ECM remodeling (e.g., metalloproteinases), have been suggested to play a role in the etiology of CL/P; hence, these may be considered likely targets for the development of new preventive and/or therapeutic strategies. In this context, investigations are being conducted on new therapeutic approaches based on tissue bioengineering, associating stem cells with biomaterials, signaling molecules, and innovative technologies. In this review, we discuss the role of genes involved in ECM composition and remodeling during secondary palate formation and pathogenesis and genetic etiology of CL/P. We also discuss potential therapeutic approaches using bioactive molecules and principles of tissue bioengineering for state-of-the-art CL/P repair and palatal reconstruction.

Dipyridamole-loaded 3D-printed bioceramic scaffolds stimulate pediatric bone regeneration in vivo without disruption of craniofacial growth through facial maturity

This study investigates a comprehensive model of bone regeneration capacity of dypiridamole-loaded 3D-printed bioceramic (DIPY-3DPBC) scaffolds composed of 100% beta-tricalcium phosphate (β -TCP) in an immature rabbit model through the time of facial maturity. The efficacy of this construct was compared to autologous bone graft, the clinical standard of care in pediatric craniofacial reconstruction, with attention paid to volume of regenerated bone by 3D reconstruction, histologic and mechanical properties of regenerated bone, and long-term safety regarding potential craniofacial growth restriction. Additionally, long-term degradation of scaffold constructs was evaluated. At 24 weeks in vivo, DIPY-3DPBC scaffolds demonstrated volumetrically significant osteogenic regeneration of calvarial and alveolar defects comparable to autogenous bone graft with favorable biodegradation of the bioactive ceramic component in vivo. Characterization of regenerated bone reveals osteogenesis of organized, vascularized bone with histologic and mechanical characteristics comparable to native bone. Radiographic and histologic analyses were consistent with patent craniofacial sutures. Lastly, through application of 3D morphometric facial surface analysis, our results support that DIPY-3DPBC scaffolds do not cause premature closure of sutures and preserve normal craniofacial growth. Based on this novel evaluation model, this DIPY-3DPBC scaffold strategy is a promising candidate as a safe, efficacious pediatric bone tissue engineering strategy.

Neurophysiological changes and chronic pain in cleft patients

The aim of this study was to evaluate if patients after orofacial cleft repair experience neurophysiological changes with consecutive chronic pain states after surgery. Patients (n = 48) with a repaired orofacial cleft (CLP) recruited in a support group took part in a survey including five questionnaires. They revealed pain states, described cleft situation and history, and epidemiological data. Patients' quality of life and psychological comorbidity after the surgical procedures were assessed with the Oral Health Impact Profile (OHIP), the Giessen Subjective Complaints List (GSCL) and the Hospital Anxiety and Depression Scale (HADS). Furthermore, psychosocial impairment was documented. 39 out of 48 subjects with CLP reported to have experienced pain during the last 6 months. Pain was proven to be already chronic for 36 persons. Locations of pain were the orofacial region, back and limbs. Neurophysiological perception to cold, warmth, pressure and touch were found to be inhomogeneous. Local disturbances of subjective sensitivity in hard and soft tissues in the operated region are suspicious for neuropathic disorders and peripheral and central sensitization. 16 participants also reported that during dental interventions higher doses of local analgesia were necessary to achieve a pain free condition. Overall participants with CLP demonstrated elevated levels for anxiety and depression. As a conclusion for daily routine, CLP patients are considered to be at a higher risk to develop chronic pain states. To avoid these, proper pain and psychological management must be performed from early childhood. Further clinical studies examining patients with neurophysiological diagnostic tools are needed.