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Volumetric analysis in the upper left maxilla. (a) Optically scanned preexpansion model. (b) Optically scanned postexpansion model. (c) Superimposed pre- and postexpansion models. Software used: Geomagic Studio 2013, Raindrop Geomagic, NC, USA.
Source publication
This pilot study aimed at investigating the safety and feasibility of pre-augmentation soft tissue expansion (STE). Tissue expanders of different sizes (from 240 to 1300 mm ³ ) were implanted subperiosteally in four patients requiring vertical and/or horizontal bone augmentation, and left in situ for 20–60 days, according to the expander size. Guid...
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Implantoprosthetic rehabilitation has become the main method to reestablish totally or partially edentulous patients, with a high success rate. However, some complications can cause implant loss. The main one is periimplantitis, with bone loss around the osseointegrated implant. However, implant fractures or incorrect implant position may compromis...
Citations
... The majority of the studies reported the defect sites in both the maxilla and the mandible [22,32,33,37,[45][46][47][48]. The remaining assessments only included defect sites in the posterior area of the mandible [49,50], followed by the maxillary [23,51,52]and mandibular anterior location [53], respectively. ...
... Defect site. The conducted investigations have reported the application of STE on both mandibular and maxillary regions [22,32,33,37,[45][46][47][48]. Some studies focused on the upper arch [23,51,52]. ...
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.
... Cast models were scanned with a 3D scanner (Trios3 ® , 3Shape, Denmark) and transferred into a database integrated software (Geomagic Control X, 3D systems, USA) to measure soft tissue dimensional changes ( Figure 3A). Scanned 3D images were exported as STL files (standard tessellation language), and each patient's images at different time points were superimposed using adjacent teeth from the defective site as the reference point and landmark as the best-fit initial alignment [21,22]. Three vertical cross sections and three horizontal cross sections were measured to observe the horizontal and vertical changes. ...
Objectives:
The purpose of this study was to evaluate the effectiveness of the intraoral use of subperiosteally placed self-inflating tissue expanders for subsequent bone augmentation and implant integrity.
Material and methods:
A prospective, multicenter, randomized controlled trial was performed on patients requiring alveolar bone graft for dental implant insertion. Patients were assigned to three groups: tissue expansion and tunneling graft (TET group), tissue expansion and conventional bone graft (TEG), and control group without tissue expansion. Dimensional changes of soft tissue and radiographic vertical bone gain, retention, and peri-implant marginal bone changes were evaluated and secondary outcomes; clinical complications and thickness changes of expanded overlying tissue were assessed.
Results:
Among 75 patients screened, a total of 57 patients were included in the final analysis. Most patients showed uneventful soft tissue expansion without any inflammatory sign or symptoms. Ultrasonographic measurements of overlying gingiva revealed no thinning after tissue expansion (p > 0.05). Mean soft vertical and horizontal tissue measurements at the end of its expansion were 5.62 and 6.03 mm, respectively. Significantly higher vertical bone gain was shown in the TEG (5.71 ± 1.99 mm) compared with that in the control patients (4.32 ± 0.97 mm; p < 0.05). Hard tissue retention- measured by bone resorption after 6 months-showed that control group showed higher amount of vertical (2.06 ± 1.00 mm) and horizontal bone resorption (1.69 ± 0.81 mm) compared to that of the TEG group (p < 0.05).
Conclusion:
The self-inflating tissue expander effectively augmented soft tissue volume and both conventional bone graft and tunneling techniques confirmed their effectiveness in bone augmentation. With greater amount of bone gain and better 6 month hard tissue integrity, the TEG group compared to the control group-without tissue expansion-showed that the combined modality of tissue expander use and guided bone regeneration (GBR) technique may improve the outcome and predictability of hard tissue augmentation.
... Although one might think that the bone graft volumes generated might be insufficient at the time of implant surgery, as graft resorption during osseous healing is still not predictable, it must be noted that prefabricated grafts could be made of biomaterials that have a degradation rate in concordance with the remodeling processes of the target tissue. 10 In this context, a 2-step regenerative protocol can be implemented: pre-augmentation STE technique (Fig. 3), 5,28 followed by regeneration with prefabricated grafts. In this approach, a suitable self-inflating soft-tissue expander and its Atrophic posterior mandibles and virtually designed grafts The results of this retrospective study should be interpreted with caution, as it has certain limitations. ...
... Although one might think that the bone graft volumes generated might be insufficient at the time of implant surgery, as graft resorption during osseous healing is still not predictable, it must be noted that prefabricated grafts could be made of biomaterials that have a degradation rate in concordance with the remodeling processes of the target tissue. 10 In this context, a 2-step regenerative protocol can be implemented: pre-augmentation STE technique (Fig. 3), 5,28 followed by regeneration with prefabricated grafts. In this approach, a suitable self-inflating soft-tissue expander and its Atrophic posterior mandibles and virtually designed grafts The results of this retrospective study should be interpreted with caution, as it has certain limitations. ...
Objective:
The present study was conducted to evaluate the effect of soft tissue augmentation using a self-inflating soft tissue expander when performed before horizontal alveolar ridge augmentation on the outcomes of the bone augmentation procedure. The primary outcome is the bucco-palatal radiographical changes in alveolar ridge width, while the secondary outcome is the quality of the augmented bone assessed histomorphometrically.
Material and methods:
Sixteen patients underwent horizontal alveolar ridge augmentation using autogenous bone. For the test group, soft tissue expanders were used in a separate surgery before bone grafting surgery. For the control group, patients received treatment including single surgery of bone grafting associated with periosteal releasing incision Implants were placed in both groups six months after bone augmentation. Bucco-palatal changes in alveolar ridge width were evaluated via cone-beam computed tomography. Augmented bone quality was assessed histomorphometrically.
Results:
After six months. Regarding Radiographic bone width, there was no statistically significant difference between the two groups, as mean bone width in group I and group II were 8.57 mm, and 8.75 mm, respectively. Regarding Histomorphometric analysis, Group I showed significantly higher mean bone surface area fraction, higher median mature collagen area fraction and higher median blood vessel count than Group II (P-value = 0.012), (P-value = 0.004) and (P-value = 0.014) respectively.
Conclusion:
within the limitations of the present study, soft tissue expander has no influence on bone width gain after horizontal alveolar ridge augmentation with an autogenous bone block but may have a positive effect on the quality of augmented bone.
This review explores the evolution of the use of hydrogels for craniofacial soft tissue engineering, ranging in complexity from acellular injectable fillers to fabricated, cell-laden constructs with complex compositions and architectures. Addressing both in situ and ex vivo approaches, tissue restoration secondary to trauma or tumor resection is discussed. Beginning with relatively simple epithelia of oral mucosa and gingiva, then moving to more functional units like vocal cords or soft tissues with multilayer branched structures, such as salivary glands, various approaches are presented toward the design of function-driven architectures, inspired by native tissue organization. Multiple tissue replacement paradigms are presented here, including the application of hydrogels as structural materials and as delivery platforms for cells and/or therapeutics. A practical hierarchy is proposed for hydrogel systems in craniofacial applications, based on their material and cellular complexity, spatial order, and biological cargo(s). This hierarchy reflects the regulatory complexity dictated by the Food and Drug Administration (FDA) in the United States prior to commercialization of these systems for use in humans. The wide array of available biofabrication methods, ranging from simple syringe extrusion of a biomaterial to light-based spatial patterning for complex architectures, is considered within the history of FDA-approved commercial therapies. Lastly, the review assesses the impact of these regulatory pathways on the translational potential of promising pre-clinical technologies for craniofacial applications.
Statement of Significance
While many commercially available hydrogel-based products are in use for the craniofacial region, most are simple formulations that either are applied topically or injected into tissue for aesthetic purposes. The academic literature previews many exciting applications that harness the versatility of hydrogels for craniofacial soft tissue engineering. One of the most exciting developments in the field is the emergence of advanced biofabrication methods to design complex hydrogels systems that can promote the functional or structural repair of tissues. To date, no clinically available hydrogel-based therapy takes full advantage of current pre-clinical advances. This review surveys the increasing complexity of the current landscape of available clinical therapies and presents a framework for future expanded use of hydrogels with an eye toward translatability and U.S. regulatory approval for craniofacial applications.
Background:
Craniofacial soft-tissue defects mostly have an impact on the treatment of various oral diseases. Tissue expander is an important technique for tissue reconstruction, especially for soft tissues in reconstructive surgery.
Objective:
This research aimed to develop a new self-swelling tissue expander, namely hydrogel, for soft tissue reconstruction in craniofacial region.
Methods:
In vitro, the chemical and physical characteristics of hydrogel were evaluated by SEM, swelling rate, mechanical testing, EDS, and FT-IR. In vivo, the craniofacial implant model of SD rats were divided into group A as control, group B with hydrogels for 1 week expansion, group C for 2 weeks and group D for 4 weeks (n = 5), and the effects were analyzed by HE staining, histological and radiographic evaluation.
Results:
The in vitro results suggested that dry hydrogel possessed a uniform surface with micropores, the surface of post-swelling hydrogel formed three-dimensional meshwork. Within 24 hours, hydrogels expanded markedly, then slowed down. The mechanical property of hydrogels with longer expansion was better, whose main elements were carbon and oxygen. FT-IR also verified its molecular structure. In vivo, the wounds of rats recovered well, hydrogels could be removed as one whole piece with original shape and examined by radiographic evaluation, besides, the expanded skin and developed fibrous capsule formed surrounding hydrogels.
Conclusion:
The new expander was designed successfully with good chemical and physical characteristics, and could be applied in an animal model to help tissue reconstruction.
Objectives:
Conventional guided bone regeneration (GBR) limits the amount of bone graft due to limited soft tissue expansion. We hypothesize that the use of tissue expander will successfully augment soft tissue prior to bone graft, allowing for sufficient amount of grafting which will lead to a more stable and effective vertical bone graft. The authors aimed to evaluate effectiveness of the novel self-inflating tissue expander for vertical augmentation in terms of soft tissue expansion, clinical outcomes, and related complications MATERIAL AND METHODS: A prospective, multicenter, randomized controlled trial was performed on patients requiring vertical augmentation. For experimental group patients, the tissue expander was subperiosteally implanted and followed by a tunneling bone graft without full flap reflection. Control patients underwent conventional vertical GBR. Primary objectives were to evaluate the dimensional changes of soft tissue and radiographic vertical bone gain and retention. As a secondary outcome, clinical complications and thickness changes of expanded overlying tissue were assessed and analyzed.
Results:
Twenty-three patients in each group were included. During a 4-week expansion, two of the experimental group showed over-expansion and one showed mucosal perforation associated with previous severe scars. The other patients showed uneventful expansion and mean tissue augmentation was 6.88 ± 1.64 mm vertically. Ultrasonographic measurements of overlying gingiva revealed no thinning after tissue expansion (P>0.05). Significantly higher vertical bone gain was shown in the experimental group (5.12 ± 1.25 mm) compared with that in the control patients (4.22 ± 1.15 mm; P<0.05). After a 6-month retention period, the mean vertical bone measurement of the controls had decreased to 1.90 mm (55.0% reduction), which was a significantly greater decrease than that in the experimental group (mean 3.55 mm, 30.7% reduction; P<0.05).
Conclusion:
Our results demonstrated the effectiveness of tissue expanders followed by tunneling bone graft for vertical augmentation; however, studies comparing the two techniques without tissue expanders are needed to elucidate the net effect of tissue expansion.
