Expanding soft tissue with Osmed tissue expanders in the goat maxilla

Gingivo-Periosteal Expansion of Edentulous Jaw Crest with An Osmotic Self-Inflatable Expander: A Preclinical in Vivo Study

This study examined the biocompatibility and expansion volume of tissue expanders utilizing rabbits and beagles as experimental models. The self-inflatable expander was provided using a Tissue balloon® (Neobiotech Co., Seoul, Korea). In 9 adult rabbits, a Tissue balloon® was placed under the lateral mandibular periosteum via an extraoral approach. After 2, 3, and 4 weeks (n=3), the expanders were removed, and soft tissue and bone samples were collected for analysis. Histomorphometric analysis and measurements of expander characteristics were performed. In 5 Beagles, all premolars were extracted. Three months after extraction, tissue expanders were placed in the maxilla and mandible, adjacent to dental extraction sites, and removed after 3 weeks. Gingival parameters were measured before and after expansion. Blood perfusion in the oral mucosa was assessed using a laser Doppler flowmeter at different time points. After three weeks, dogs were euthanized, and tissue samples were collected for histologic analysis, focusing on inflammatory response, bone formation, and gingival thickness changes. In the rabbit study, measurements of size, weight, and volume showed significant increases over 4 weeks. Swelling peaked at 2 weeks postimplantation and then gradually stabilized. Histologic examination revealed no signs of inflammation, and expanders were covered by collagen-rich capsules. Some bone resorption was noted due to pressure from the expanders, but the resorption was not significant. In the beagle study, twenty tissue expanders were implanted; 1 expander was lost, and 9 wounds dehisced during soft tissue healing. However, no signs of infection were noted. Histologic evaluation showed bone atrophy, attributed to swelling pressure, at the recipient site. Gingival thickness was not decreased. Perfusion measurements indicated that expansion did not affect microvascular circulation adversely. Overall, both studies suggest that tissue expanders demonstrate biocompatibility and successful expansion volume in vivo, with minimal adverse effects on surrounding tissues and microvascular circulation.

Restoring Severely Atrophic Edentulous Ridge of Mandible Using Self-Expanding Tissue Expander-A Case Report

This report describes the use of Self Inflating Tissue Expanders (SITEs) to rehabilitate severely atrophic edentulous mandibular ridges, enabling successful bone grafting and implant placement. The treatment resulted in stable and complication-free implants over a seven-year follow-up, demonstrating SITEs' effectiveness in providing sufficient bone volume and soft tissue coverage for dental implants.

Hydrogel based soft tissue expanders for orodental reconstruction

Tension-free flap closure to prevent soft tissue dehiscence is a prerequisite for successful bone augmentation in orodental reconstructive surgery. Since soft tissue contour follows the underlying jaw bony architecture, resorption of alveolar (jaw) bone limits the availability of soft tissue for wound closure following major bone reconstruction, required to facilitate oral rehabilitation with endosseous dental implants following tooth loss. Although there are several clinical procedures to increase soft tissue volume, these techniques are complicated and technically demanding. Soft tissue expansion, an established technique in reconstructive surgery, is an ideal alternative to generate surplus soft tissue prior to bone augmentation and dental implant placement. Increase in tissue volume can be achieved by using soft tissue expanders (STEs). Contemporary STEs have evolved from silicone balloons to osmotically inflating hydrogel-based systems. Here, we provide an overview of STEs in clinical oral surgery, outline the current research in STEs, and an update on recent clinical trials as well as the associated complications. Also, the mechanism governing soft tissue expansion and the critical factors that control the expansion process are covered. Design considerations for STEs for intraoral applications are given particular attention. Finally, we present our perspectives on utilization of minimally invasive methods to administer STEs for orodental applications. STATEMENT OF SIGNIFICANCE: Soft tissue expansion is required for a range of reconstructive applications and more notably in regenerative dentistry for vertical bone augmentation. This review describes the commercially available soft tissue expanders along with the latest systems being currently developed. This review insightfully discusses the biological and physical mechanisms leading to soft tissue expansion and critically assesses the design criteria of soft tissue expanders. A particular focus is given on the development of a new generation of hydrogel-based soft tissue expanders; their chemistry and required physical properties for tissue expansion is described and the obstacles towards clinical translations are identified. Finally, the review elaborates on promising minimally invasive injectable hydrogel-based tissue expanders and highlights the beneficial features of these systems.

Soft tissue expansion using self-inflating osmotic hydrogel expanders prior to bone augmentation: healing and complications. Evidence-based review

AIM

This review aims to assess complication rates, soft tissue gain, and bone gain associated with the use of self-inflating osmotic hydrogel tissue expanders (SOHTEs) for soft tissue expansion (STE).

METHODS

A comprehensive search on Pubmed and Google Scholar databases was conducted to identify human studies using SOHTEs for STE; last searched in March 2023. Expansion phase details and expander variables were documented. Complication rates, soft tissue gain, and bone gain reported in each study were also recorded. The inclusion criteria encompassed human studies ranging from evidence levels II-IV (Oxford Centre for Evidence-Based Medicine Levels of Evidence), without specific date limits. For assessing bias in randomized controlled trials (RCTs), a Risk of Bias tool was employed. The synthesised results were presented through tables, sunburst plots, and bar charts.

RESULTS

A total of 13 studies were identified, comprising 4 RCTs, 1 cohort study, and 8 case-series. Employment of SOHTEs yielded an overall complication rate of 17% (24/140 sites), with expander perforation accounting for 9.3% (13/140) of the sites. Specific complication rates included dehiscence (1.4%, 2/140 sites), paraesthesia (1.4%, 2/140 sites), and infection (1.4%, 2/140 sites). All randomized controlled trials (RCTs) were categorised at Level II. The remaining investigations primarily consisted of Level IV case-series lacking controls. All studies demonstrated some concerns towards bias.

CONCLUSION

STE studies using SOHTEs exhibit a reduction in complications associated with bone augmentation in scenarios of inadequate soft tissue coverage. Preliminary evidence suggests potential benefits even in cases with sufficient soft tissue. Adherence to procedural precautions may reduce the risk of expander perforations, further diminishing complications. Subsequent studies should incorporate individual patient and expander variables in their reports to explore the impact of expansion phases on complication rates, as well as bone and soft tissue augmentation.

An Overview of Scaffolds and Biomaterials for Skin Expansion and Soft Tissue Regeneration: Insights on Zinc and Magnesium as New Potential Key Elements

The utilization of materials in medical implants, serving as substitutes for non-functional biological structures, supporting damaged tissues, or reinforcing active organs, holds significant importance in modern healthcare, positively impacting the quality of life for millions of individuals worldwide. However, certain implants may only be required temporarily to aid in the healing process of diseased or injured tissues and tissue expansion. Biodegradable metals, including zinc (Zn), magnesium (Mg), iron, and others, present a new paradigm in the realm of implant materials. Ongoing research focuses on developing optimized materials that meet medical standards, encompassing controllable corrosion rates, sustained mechanical stability, and favorable biocompatibility. Achieving these objectives involves refining alloy compositions and tailoring processing techniques to carefully control microstructures and mechanical properties. Among the materials under investigation, Mg- and Zn-based biodegradable materials and their alloys demonstrate the ability to provide necessary support during tissue regeneration while gradually degrading over time. Furthermore, as essential elements in the human body, Mg and Zn offer additional benefits, including promoting wound healing, facilitating cell growth, and participating in gene generation while interacting with various vital biological functions. This review provides an overview of the physiological function and significance for human health of Mg and Zn and their usage as implants in tissue regeneration using tissue scaffolds. The scaffold qualities, such as biodegradation, mechanical characteristics, and biocompatibility, are also discussed.

Gaining Soft Tissue with a Hydrogel Soft Tissue Expander: A Case Report

In this case report, we describe the treatment of a patient referred to our clinic with a hopeless tooth 21 with an attached pontic. The aim of this case report was to, first, describe the advantages and disadvantages of gaining soft tissue with a self-inflating soft tissue expander before performing a bone augmentation procedure in implant dentistry in the esthetic zone. Second, we describe how an amalgam tattoo, caused by a previously performed apicoectomy that made the extension of the raised flap to cover the augmented site esthetically undesirable, was removed. Two silicone enveloped Osmed hydrogel self-inflating soft tissue expanders were placed submucosally on the right- and left-hand side of the amalgam tattoo. One of these two perforated the overlaying mucosa after 24 days. Both tissue expanders were removed, the amalgam tattoo was excided, the site augmented, and an implant with a crown and a pontic was placed.

Expanding intestinal segment using osmotic hydrogel: An in vivo study

Intestinal circumferential expansion is essential for bowel lengthening in patients with Short Bowel Syndrome. We hypothesized use of an endoluminal osmotic hydrogel expander (EOHE) as a novel approach for intestinal expansion. An EOHE was introduced into an isolated intestinal segment of New Zealand rabbits, with a similar segment created as a control. After 4weeks, the segments were retrieved for analysis. Weight, inflammatory markers and fluoroscopy data was recorded weekly. EOHE allowed successful expansion of intestinal segments from 4.68 ± 0.35 to 9.79 ± 0.35 cm (p = 0.01). Increase in intestinal length was 167.8 ± 35.21% in segments with EOHE vs. 23.03 ± 4.2% in the control group (p < 0.01). A significant intestinal dilatation (214.4 ± 1.58 vs. 34.59 ± 1.23%, p < 0.01) was demonstrated. Hematoxylin and eosin stain revealed conservation of intestinal architecture with muscle hypertrophy and flattening of the epithelium possibly due to compression. No reduction of rabbit weight, inflammatory markers or liver damage was described. EOHE appears to produce safe intestinal expansion, achieving increased length and dilatation suitable for lengthening procedure. This approach may allow development of similar techniques to expand bowel in short bowel patients. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1304-1309, 2019.

Oral tissue response to soft tissue expanders prior to bone augmentation: in vitro analysis and histological study in dogs

Purpose

To determine whether the swelling and mechanical properties of osmotic self-inflating expanders allow or not the induction of intraoral soft tissue expansion in dogs.

Methods

Three different volumes (0.15, 0.25, and 0.42 mL; referred to respectively as the S, M, and L groups) of soft tissue expanders (STEs) consisting of a hydrogel core coated with a silicone-perforated membrane were investigated in vitro to assess their swelling behavior (volume swelling ratio) and mechanical properties (tensile strength, tensile strain). For in vivo investigations, the STEs were subperiosteally inserted for 4 weeks in dogs (n=5). Soft tissue expansion was clinically monitored. Histological analyses included the examination of alveolar bone underneath the expanders and thickness measurements of the surrounding fibrous capsule.

Results

The volume swelling ratio of all STEs did not exceed 5.2. In tensile mode, the highest mean strain was registered for the L group (98.03±0.3 g/cm), whereas the lowest mean value was obtained in the S group (81.3±0.1 g/cm), which was a statistically significant difference (P<0.05). In addition, the S and L groups were significantly different in terms of tensile strength (1.5±0.1 g/cm for the S group and 2.2±0.1 g/cm for the L group, P<0.05). Clinical monitoring showed successful dilatation of the soft tissues without signs of inflammation up to 28 days. The STEs remained volumetrically stable, with a mean diameter in vivo of 6.98 mm, close to the in vitro post-expansion findings (6.69 mm). Significant histological effects included highly vascularized collagen-rich fibrous encapsulation of the STEs, with a mean thickness of 0.67±0.12 mm. The bone reaction consisted of resorption underneath the STEs, while apposition was observed at their edges.

Conclusions

The swelling and mechanical properties of the STEs enabled clinically successful soft tissue expansion. A tissue reaction consisting of fibrous capsule formation and bone loss were the main histological events.

Soft Tissue Augmentation Techniques and Materials Used in the Oral Cavity: An Overview

PURPOSE

Oral soft tissue augmentation or grafting procedures are often necessary to achieve proper wound closure after deficits resulting from tumor excision, clefts, trauma, dental implants, and tooth recessions.

MATERIALS AND METHODS

Autologous soft tissue grafts still remain the gold standard to acquire a functionally adequate zone of keratinized attached gingiva. However, soft tissue substitutes are more commonly used because they minimize morbidity and shorten surgical time.

RESULTS

This review aimed to assess soft tissue grafting techniques and materials used in the oral cavity from existing literature. There are a large variety of materials and techniques, including grafts, local flaps, allogenic derived matrices such as acellular dermal allograft, xenogenic tissue matrices from animal origin, and synthetic materials.

CONCLUSIONS

Tissue engineering of oral mucosa represents an interesting alternative to obtain sufficient autologous tissue for reconstructing oral wounds using biodegradable scaffolds, and may improve vascularization and epithelialization, which are critical for successful outcomes.

Pre-augmentation soft tissue expansion: an overview

OBJECTIVES

The aim of this study was to explore the development of soft tissue expanders, their different types and their potential applications prior to bone augmentation and implant placement.

MATERIAL AND METHODS

A review of pertinent literature was performed using PubMed to comprehend the dynamics of soft tissue expanders and determine the current position of their pre-augmentation applications.

RESULTS

There is promising, albeit preliminary information regarding the benefits of pre-augmentation soft tissue expansion. Findings cannot be generalised due to relatively small sample size.

CONCLUSIONS

Further clinical trials with larger sample sizes and long-term follow-up are needed before soft tissue expanders can be confidently applied in everyday clinical practice.

Self-inflating oral tissue expander for ridge augmentation in the severely atrophic mandible

In dentistry, tissue expanders have been used to obtain sufficient soft tissue for alveolar bone augmentation in the severely atrophic ridge. Herein, we review two cases of soft tissue augmentation using a self-inflating tissue expander in patients in the Department of Oral and Maxillofacial Surgery at Ewha Womans University Mokdong Hospital for bone graft and implant operations. The results of each patient were presented using pre-operative and post-operative radiographs and clinical exams. The results of our study indicate successful bone graft and implant surgery using a self-inflating tissue expander.