Root coverage using a coronally advanced flap with or without acellular dermal matrix: a meta-analysis

Urethral Tissue Reconstruction Using the Acellular Dermal Matrix Patch Modified with Collagen-Binding VEGF in Beagle Urethral Injury Models

Objectives

Urethral tissue reconstruction for hypospadias is challenging for urologists. In this study, bovine acellular dermal matrix (ADM) patch loading with collagen-binding vascular endothelial growth factor (CBD-VEGF) was used to repair the urethral injury in beagles.

Methods

The safety and effectiveness of the scaffold implantation were carefully evaluated by comparing among the urethral injury control group, ADM implantation group, and ADM modified with CBD-VEGF implantation group during 6 months. Urodynamic examination, urethral angiography, and pathological examination were performed to evaluate the recovery of urethral tissue.

Results

Stricture, urethral diverticulum, and increased urethral closure pressure were observed in the control group. Fistula was observed in one animal in the ADM group. By contrast, no related complications or other adverse situations were observed in animals treated with ADM patch modified with CBD-VEGF. The average urethra diameter was significantly smaller in the control animals than in scaffold implantation groups. Pathological examination revealed more distribution of proliferative blood vessels in the animals treated with ADM modified with CBD-VEGF.

Conclusions

Overall, ADM patches modified with CBD-VEGF demonstrated an optimized tissue repair performance in a way to increase tissue angiogenesis and maintain urethral function without inducing severe inflammation and scar formation.

Comparison of Vestibular Depth Relapse and Wound Healing After Reconstructive Preprosthetic Surgery Using Cryopreserved Amniotic Membrane and Acellular Dermal Matrix - A Comparative Study

Introduction:

The significance of membranes as wound dressing in oral surgeries has been reported by previous studies. The aim of the present split-mouth randomized clinical study was to assess and compare the wound dressing properties of acellular dermal matrix (ADM) and cryopreserved human amniotic membrane (AM) after reconstructive preprosthetic oral surgery.

Materials and Methods:

Twenty-eight patients with complete mandibular edentulism and resorbed alveolar bone were included. After taking mandibular impression, a clear acrylic splint with increased labial flange height was created. In each participant, labial vestibular depth was elevated using the Clark's technique. Subsequently, half of the exposed periosteum was covered with ADM while the other half was covered with cryopreserved human AM. Vestibule depth and relapse in the two sides were measured immediately after vestibuloplasty and at the end of the 1^st week, 2^nd week, 1^st month, and 3^rd months with graduations of 0.1 mm. Furthermore, after 3 and 7 days, samples were collected from graft material, and the macrophage population was analyzed by flow cytometry.

Results:

There was no significant difference in the relapse of vestibule depth between the two grafts at different time intervals. However, the frequency of wound-infiltrating macrophages (CD68⁺ cells) was significantly higher in areas covered by ADM after 3 and 7 days.

Discussion:

ADM is as effective as cryopreserved AM in terms of maintaining the postoperative vestibular depth. On the other hand, our results suggested that the onset of healing phase in ADM-covered areas occurs faster compared to the periosteum covered with cryopreserved human AM. This clinical trial showed significantly faster postoperative healing onset when ADM was used than when cryopreserved human AM was applied on the periosteum.

Case Report: Surgical Closure of Chronic Soft Tissue Defects Using Extracellular Matrix Graft Augmented Tissue Flaps

Chronic soft tissue defects are notoriously difficult to heal. Surgical reconstruction of chronic defects using tissue flaps is a routine approach for closure of challenging chronic defects. Due to the poor tissue quality of chronic defects and associated inflammation, infection and impaired blood supply the success of flap closure is marred by reported complication rates of 25-58%. Extracellular matrix (ECM)-based graft materials are commonly used for resolving chronic wounds and in plastic and reconstructive procedures to create a scaffold for tissue regeneration. We hypothesized combination use of ECM grafts with tissue flaps in a single-stage surgical procedure would reduce complications and improve outcomes in the closure of chronic soft tissue defects. We report a case series (n = 9) of chronic soft tissue defect reconstruction using this modified procedure of ECM graft augmented flap closure. Defects included pressure injuries and surgical dehiscence and ranged in wound age from 5 months to 7 years. Successful uncomplicated healing was achieved in six defects. Post-operative complications (dehiscence) occurred in two defects, however, these healed via secondary intention without additional surgical intervention. All healed defects exhibited acceptable cosmesis and "normal" function, with 100% patient satisfaction. Augmentation of tissue flaps with ECM graft materials in this modified single-stage procedure may improve outcomes and minimize typical complications encountered in flap closure of chronic defects attributed to inflammation, infection, hypoperfusion, and dead space.

Creeping attachment: A literature review

OBJECTIVE

Mucogingival surgery has been widely applied in clinics. An interesting phenomenon after mucogingival surgery is the coronal migration of gingival margin, which is described as "creeping attachment." The goal of this review is to summarize the characteristics, significance, mechanism, and manifestation of the creeping attachment after mucogingival surgery and to describe the factors associated with its occurrence.

OVERVIEW

A total of 82 relevant articles were included in the literature review. The characteristics and significance of the creeping attachment after mucogingival surgery were analyzed. The mechanism of the creeping attachment was explored. Different manifestations of and factors associated with creeping attachment were summarized.

CONCLUSIONS

Creeping attachment may occur to obtain additional root coverage after the healing of various mucogingival surgeries. However, this coverage is not always complete nor entirely predictable.

CLINICAL SIGNIFICANCE

Creeping attachment plays an important role in the prognosis of mucogingival surgeries. This review will help clinicians get a thorough recognition and understanding of this phenomenon.

Enhanced Wound Healing Potential of Primary Human Oral Fibroblasts and Periodontal Ligament Cells Cultured on Four Different Porcine-Derived Collagen Matrices

Xenogenic collagen-based matrices represent an alternative to subepithelial palatal connective tissue autografts in periodontal and peri-implant soft tissue reconstructions. In the present study, we aimed to investigate the migratory, adhesive, proliferative, and wound-healing potential of primary human oral fibroblasts (hOF) and periodontal ligament cells (hPDL) in response to four commercially available collagen matrices. Non-crosslinked collagen matrix (NCM), crosslinked collagen matrix (CCM), dried acellular dermal matrix (DADM), and hydrated acellular dermal matrix (HADM) were all able to significantly enhance the ability of hPDL and hOF cells to directionally migrate toward the matrices as well as to efficiently repopulate an artificially generated wound gap covered by the matrices. Compared to NCM and DADM, CCM and HADM triggered stronger migratory response. Cells grown on CCM and HADM demonstrated significantly higher proliferative rates compared to cells grown on cell culture plastic, NCM, or DADM. The pro-proliferative effect of the matrices was supported by expression analysis of proliferative markers regulating cell cycle progression. Upregulated expression of genes encoding the adhesive molecules fibronectin, vinculin, CD44 antigen, and the intracellular adhesive molecule-1 was detected in hPDL and hOF cells cultured on each of the four matrices. This may be considered as a prerequisite for good adhesive properties of the four scaffolds ensuring proper cell–matrix and cell–cell interactions. Upregulated expression of genes encoding TGF-β1 and EGF growth factors as well as MMPs in cells grown on each of the four matrices provided support for their pro-proliferative and pro-migratory abilities. The expression of genes encoding the angiogenic factors FGF-2 and VEGF-A was dramatically increased in cells grown on DADM and HADM only, suggesting a good basis for accelerated vascularization of the latter. Altogether, our results support favorable influence of the investigated collagen matrices on the recruitment, attachment, and growth of cell types implicated in oral soft tissue regeneration. Among the four matrices, HADM has consistently exhibited stronger positive effects on the oral cellular behavior. Our data provide solid basis for future investigations on the clinical application of the collagen-based matrices in surgical periodontal therapy.

Clinical efficacy of xenogeneic and allogeneic 3D matrix in the management of gingival recession: a systematic review and meta-analysis

OBJECTIVE

A systematic review and meta-analysis was thus conducted to answer the following focused question based on PICO strategy: Is there any 3D matrix biomaterial used for root coverage of human Miller class I and II defects equivalent with the connective tissue graft in localized defects of at least 2 mm and 3 mm?

MATERIAL AND METHODS

The search on electronic database included MEDLINE, Cochrane Central Register of Controlled Trials, Clinical Trials.gov, Web of Science, and New Zealand/Australian Clinical Trials. Only randomized clinical trials (RCTs) that compared connective tissue graft (CTG) with at least one 3D matrix alone for root coverage in Class I and II Miller localized defects of at least 2 mm, with at least 6 months follow-up, were included in this systematic review.

RESULTS

A total of 14 studies were included for meta-analysis (12 compared CTG with acellular dermal matrix allograft and 2 compared CTG with Xenogenic Collagen Matrix). Relative root coverage showed no significant difference among the materials, for either 2 or 3 mm minimal recessions. For keratinized tissue width, on 2 mm recessions, CTG showed superiority above other biomaterials, but on 3 mm recessions, it seemed to have the same results. The percentage of recessions with complete root coverage for both 2 and 3 mm recessions showed similar results for all biomaterials.

CONCLUSIONS

With their limits, the present data concluded that CTG, acellular dermal matrix allograft, and xenogenic collagen matrix provided similar results for root coverage.

CLINICAL RELEVANCE

To know if there is a 3D matrix with equivalent predictable results for root coverage, that we could avoid the morbidity of the connective tissue graft for these cases.

[Research progress on substitutes for autogenous soft tissue grafts in mucogingival surgery]

Mucogingival surgery is a general term for periodontal surgeries that correct aberrant periodontal soft tissues. Conventional mucogingival surgeries with pedicle flap or autologous soft tissue graft for treatment of gingival recession and insufficient keratinized tissues are always related to disadvantages such as need for a second surgery site, limited supplies, and complaints for postoperative discomfort. In this regard, research and application of soft tissue substitutes have gained increasing attention. Various kinds of soft tissue substitutes, including acellular dermal matrix and xenogeneic collagen matrix, have been developed and applied to clinical treatment. This review aims to summarize advances in research of the characteristics and clinical effectiveness of several soft tissue substitutes and provide references for clinical application.