Gingiva thickening with a porcine collagen matrix in a preclinical dog model: Histological outcomes

Achieving the optimal emergence profile: the role of soft tissue grafting and pontic site development

Hard and soft tissue remodelling after tooth extraction may result in a concave profile at the subsequent edentulous ridge. This defect may result in a sub-optimal aesthetic transition zone between the soft tissue and the pontic, which may appear to sit on the ridge, rather than emanating from within the ridge, as would a natural tooth. To optimise aesthetics, pontic site augmentation (PSA) (increasing the volume at the pontic site) and pontic site development (PSD) (remodelling the tissue at the pontic site) may provide a solution.This article discusses the role of soft tissue grafting for PSA, alongside the techniques employed for PSD. Biomaterial substitutes may be used for soft tissue grafting; although autogenous tissue remains the gold standard. Patients may benefit from biomaterial substitutes (as no donor site is required) but evidence for long-term volumetric stability within this specific scenario is limited.Studies suggest PSD may be initiated three months post-augmentation, with minimal changes in site volume following this time point; although again, clinical data are limited. PSD can be achieved via several techniques, depending on operator and patient preference, with the ultimate goal of tissue conditioning to accept a convex fit surface that facilitates hygiene practices. PSA and PSD play key roles in the creation of a natural emergence profile at edentulous sites, leading to optimal aesthetics and cleansability.

Collagen matrix versus free gingival graft for augmentation of keratinized tissue in mandibular anterior teeth: A comparative clinical study

Background

Insufficient width of keratinized gingiva (WKG) leads to clinical attachment loss (CAL) and eventually periodontal destruction. Free gingival graft (FGG) is the gold standard to increase WKG but requires a second surgical site and poor esthetics outcomes. Hence, alternatives like collagen matrix (CM) have been developed.

Aim

The present study aims to evaluate the efficacy of CM versus FGG in augmenting WKG in the lower anterior.

Materials and Methods

Twenty patients with inadequate WKG were enrolled and allocated into two groups. Group I participants received augmentation of WKG using CM and Group II participants with FGG. Clinical parameters such as probing pocket depth, CAL, WKG, and gingival thickness were recorded at baseline, 3rd month, and 6th month. Plaque score was recorded at baseline and 6th month and wound healing index was recorded at 14th and 21st days. The parameters within the group and between the groups were compared using repeated measures of analysis of variance and independent t-test.

Results

The mean WKG of Group I and Group II in 6th month after augmentation was 3.88 ± 0.3 mm and 5.21 ± 1.0 mm, respectively, and the difference was statistically significant (P = 0.001). The mean wound healing index for Group I and Group II measured on 21st day was 5.00 ± 0.1 and 2.50 ± 0.5, respectively, and the difference in the wound healing index was statistically significant (P = 0.001).

Conclusion

Both CM and FGG are suitable for increasing the WKG. FGG aided in a marginally greater increase in WKG than CM and healing was better with CM as compared to FGG.

Effects of implant placement timing and type of soft-tissue grafting on histological and histomorphometric outcomes in a preclinical canine model

AIM

To determine the effects of implant timing and type of soft-tissue grafting on histological and histomorphometric outcomes in a preclinical model.

MATERIALS AND METHODS

Four implant placement protocols were randomly applied at the mesial root sites of the third and fourth mandibular premolars in 10 mongrel dogs: immediate placement (group IP), early placement (group EP), delayed placement with/without alveolar ridge preservation (groups ARP and DP, respectively). A connective-tissue graft (CTG) or porcine-derived volume-stable collagen matrix (VCMX) was applied to enhance the ridge profile (simultaneously with implant placement in group IP and staged for others), resulting in five sites for each combination. All dogs were sacrificed 3 months after soft-tissue grafting. Histological and histomorphometric analyses were performed, and the data were analysed descriptively.

RESULTS

CTG and VCMX were difficult to differentiate from the augmented area. The median total tissue thickness on the buccal aspect of the implant was largest in group IP/CTG (between 2.78 and 3.87 mm). The soft-tissue thickness was generally favourable with CTG at all implant placement timings. Within the DP groups, CTG yielded statistically significantly larger total and soft-tissue thickness than VCMX (p < .05). Among the groups with VCMX, group EP/VCMX showed the largest soft-tissue thickness at apical levels to the implant shoulder.

CONCLUSIONS

CTG generally led to greater tissue thickness than VCMX.

Xenogeneic collagen matrix vs. connective tissue graft for the treatment of multiple gingival recession: a systematic review and meta-analysis

The aim of this systematic review (SR) compared the effect of xenogeneic collagen matrix (XCM) vs. connective tissue graft (CTG) for the treatment of multiple gingival recession (MGR) Miller Class I and II or Cairo type I. Five databases were searched up to August 2022 for randomized clinical trials (RCTs) comparing the clinical effects of XCM vs. CTG in the treatment of MGR. The random effects model of mean differences was used to determine reduction of gingival recession (GR), gain in keratinized tissue width (KTW), gain in gingival thickness (GT) and gain in clinical attachment level (CAL). The risk ratio was used to complete root coverage (CRC) at 6 and 12 months. 10 RCTs, representing 1095 and 649 GR at 6 and 12 months, respectively, were included in this SR. The meta-analysis showed no statistically significant difference in GR reduction, KTW gain GT gain or CAL gain between groups at 6 months. However, at 12 months of follow-up, differences favoring the control group were observed (p < 0.05). CRC was significantly higher in the CTG group at 6 and 12 months. Regarding dentine hypersensitivity (DH), no statistically significant differences were found between groups at 6 and 12 months of follow-up (p < 0.05). At 12 months, CTG showed significantly superior clinical results in the treatment of MGR: however, this difference was not observed in the decrease of DH.

Clinical and histological wound healing patterns of collagen-based substitutes: An experimental randomized controlled trial in standardized palatal defects in humans

AIM

To evaluate the progression of wound healing of standardized palatal defects in groups using three different collagen-based wound dressings and a control group, in terms of wound closure, pain perception and descriptive histology.

MATERIALS AND METHODS

Twenty participants were enrolled in this experimental study, in whom four palatal defects were created. The defects (6 mm diameter, 3 mm depth) were randomly assigned to one of four treatment modalities: C (control), MG (Mucograft®), MD (mucoderm®) and FG (Fibro-Gide®). Photographs were taken, and pain assessment was performed before and after treatment and at 5, 7, 9, 12, 14 and 16 days after surgery. All participants wore a palatal splint for a duration of 16 days.

RESULTS

All groups achieved complete wound closure at 14 days. The percentage of the remaining open wound on day 7 amounted to 49.3% (C; interquartile range [IQR]: 22.6), 70.1% (FG; IQR: 20.7), 56.8% (MD; IQR: 26.3) and 62.2% (MG; IQR: 34.4). Statistically significant differences were found between FG and C (p =.01) and between MD and FG (p =.04). None of the participants rated pain higher than 4 out of 10 during the entire study period.

CONCLUSIONS

Collagen-based wound dressings provide coverage of open defects, albeit without acceleration of wound closure or reduction of pain. FG (which is not intended for open oral wounds) showed slower wound closure compared to C and MD.

Xenogeneic collagen matrix versus connective tissue graft for soft tissue augmentation at immediately placed implants: a prospective clinical trial

The advantages of immediate implant placement for patients include a reduced number of surgical procedures and a shorter overall treatment time. Disadvantages include a higher risk of aesthetic complications. The aim of this study was to compare xenogeneic collagen matrix (XCM) versus a subepithelial connective tissue graft (SCTG) used for soft tissue augmentation in combination with immediate implant placement without provisionalization. Forty-eight patients requiring a single implant-supported rehabilitation were selected and assigned to one of two surgical procedures: immediate implant with SCTG (SCTG group) or immediate implant with XCM (XCM group). Marginal changes in the peri-implant soft tissue and the facial soft tissue thickness (FSTT) were assessed after 12 months. Secondary outcomes included peri-implant health status, aesthetics, patient satisfaction, and perceived pain. All of the implants placed were successfully osseointegrated, resulting in 1-year survival and success rates of 100%. The patients in the SCTG group had a significantly lower mid-buccal marginal level (MBML) recession (P = 0.021) and a greater increase in FSTT (P < 0.001) than the patients in the XCM group. Using xenogeneic collagen matrix during immediate implant placement significantly increased FSTT from the baseline, leading to good aesthetic and patient satisfaction results. However, the connective tissue graft yielded better MBML and FSTT results.

Gingival biotype modification with collagen matrix or autogenous subepithelial connective tissue graft: Histologic and volumetric analyses in a beagle model

Objectives

To evaluate the volumetric effect and biocompatibility of porcine tendon-derived type I collagen matrix graft (CG) in gingival biotype modification (GBM) compared with subepithelial connective tissue graft (SCTG) in a beagle model.

Methods

Surface analysis using scanning electron microscopy and a collagen degradation assay of CG was performed in vitro. Six adult dogs were used in in vivo experiment, and each received autologous SCTG or CG at the anterior side. Histometric and three-dimensional digital volume analyses were conducted to compare quantitative changes in CG and SCTG in GBM. Immunohistochemical analysis was performed for the qualitative evaluation of CG compared to SCTG.

Results

CG had a double-layered structure, and its degradation was slower than that of other well-reported materials. No critical problems were associated with the healing procedure. Changes in gingival thickness and volume in the CG and SCTG groups were equivalent, with no significant differences between the groups. Type I collagen and vascular endothelial growth factor expression levels were similar in both groups.

Significance

CG and SCTG had equivalent potential for GBM in terms of quantity and quality. Additionally, CG could be used as a reasonable substitute for SCTG, making surgery convenient and predicting successful clinical outcomes.

Connective tissue graft versus xenogeneic collagen matrix for soft tissue augmentation at implant sites: a randomized-controlled clinical trial

OBJECTIVES

The purpose of this randomized clinical trial (RCT) is to compare xenogeneic collagen matrix (XCM) versus subepithelial connective tissue graft (SCTG) to increase soft tissue thickness at implant site.

MATERIALS AND METHODS

The study was a randomized, parallel-group controlled investigation. Thirty patients underwent buccal soft tissue thickness augmentation at the stage of implant placement by two different methods: SCTG (control group) and XCM (test group). Primary outcome was the amount of buccal soft tissue thickness gain, 3 months after the intervention. Secondary outcomes were the operation time, the amount of keratinized mucosa (KM), pain syndrome (PS), and patients' quality of life (QL). Histologic evaluation was also performed.

RESULTS

The amount of soft tissue thickness gain was 1.55±0.11 mm in SCTG group, and 1.18±0.11mm in XCM group. The difference between the SCTG and XCM was -0.366 (-0.66 to -0.07; p=0.016). Operation time with XCM was 8.4 (3.737 to 13.06) min shorter than that with the SCTG (p=0.001). KT, PS, and QL for both groups were not statistically significantly different at any time point (p>0.05). At histological examination, the general picture in both groups was similar. No significant differences between the studied groups in most indices, except for the average and maximum formation thickness, cellularity of the basal, mitotic activity and also maximum length of rete ridges.

CONCLUSION

Within limitations, this study demonstrates that the use of SCTG provides a statistically significant superior soft tissue thickness gain than XCM for soft tissue augmentation procedures around implants.

CLINICAL RELEVANCE

XCM can be used as the method of choice for increasing the thickness of soft tissues.

Minimal invasiveness in soft tissue augmentation at dental implants: A systematic review and meta-analysis of patient-reported outcome measures

The aim of this study was to compare patient-reported outcome measures (PROMs) of soft tissue substitutes versus autogenous grafts for soft tissue augmentation procedures at implant sites. Comprehensive and systematic literature searches were performed until December 2021. A focused question was formulated based on the Population, Intervention, Comparison and Outcome criteria (PICO): In patients with dental implants undergoing soft tissue augmentation (P), do soft tissue substitutes (I) compared to autogenous soft tissue graft (SCTG [subepithelial connective tissue graft]) (C) limit the post-operative morbidity and other patient reported-outcomes measures (O). Randomized controlled clinical trials, prospective-, retrospective- and case-series studies were included. Meta-analyses were performed whenever possible and the results were expressed as weighted mean differences (WMD). A total of 29 clinical studies were included. For mucosal thickness gain, soft tissue substitutes significantly reduced the pain perception compared to SCTG (n = 4; WMD = 14.91 Visual Analog Scale [VAS] units; 95% confidence interval [CI] 6.42-23.40; P < .0006) based on a 0-100 VAS scale. Based on a 0-10 VAS scale, a borderline significance of pain reduction was found when soft tissue substitutes were applied (n = 4; WMD = 1.62 VAS units; 95% CI 0.01-3.23; P = .05). For keratinized tissue gain, soft tissue substitutes significantly reduced the pain perception after keratinized tissue augmentation compared to SCTG based on a 0-100 VAS scale (n = 2; WMD = 21.43 VAS units; 95% CI 12.58-30.28; P < .0001). Based on the 0-10 VAS scale, soft tissue substitutes significantly reduced the pain as compared to SCTG (n = 4; WMD = 1.65 VAS units; 95% CI 0.66-2.64; P = .001). Regarding pain medication, soft tissue substitutes required less painkillers (n = 6; WMD = 1.56 tablets; 95% CI 1.22-1.91; P < .00001) after soft tissue augmentation. The surgery time was significantly reduced when soft tissue substitutes were used (n = 5; WMD = 10.9 minutes; 95% CI 4.60-17.19; P < .00001). There were no significant differences in satisfaction, aesthetics, and quality of life (OHIP-14) between soft tissue substitutes and autogenous grafts following soft tissue augmentation at implants sites. Soft tissue substitutes, compared to autogenous grafts, significantly improve PROMs following soft tissue augmentation at implant sites. Soft tissue substitutes can reduce pain perception, amounts of painkillers and surgery time while achieving similar levels of patient´s satisfaction as autogenous grafts without impairing the clinical outcomes. The current evidence indicates that they constitute a valid and reliable alternative to minimize the invasiveness in soft tissue augmentation procedures at implant sites.

Comparison of two types of xenogeneic matrices to treat single gingival recessions: A randomized clinical trial

BACKGROUND

Xenogeneic matrices (XMs) have been increasingly used for root coverage procedures. This study compared the use of two types of XM (collagen matrix [CM] and xenogeneic acellular dermal matrix [XDM]) associated with the coronally advanced flap technique (CAF) to treat single gingival recessions.

METHODS

Seventy-five patients presenting single RT1 gingival recession were treated by CAF (control group, n = 25), CAF+CM (test group 1, n = 25), or CAF+XDM (test group 2, n = 25) and completed 6-month follow-up. Clinical, patient-centered, and esthetic assessments were performed and intra- and intergroup differences were analyzed.

RESULTS

At 6 months, the mean recession reduction for CAF, CAF+CM, and CAF+XDM was 2.4 ± 0.8 mm, 2.4 ± 0.9 mm and 2.1 ± 0.8 mm, respectively (P > 0.05). The corresponding mean percentage of root coverage was 78.9% ± 26.2% for CAF, 78.0% ± 28.5% for CAF+CM, and 65.6% ± 26.9% for CAF+XDM (P > 0.05). Dentin hypersensitivity and esthetic conditions showed significantly improvements in all groups. Test groups presented significant gains in gingival thickness (GT; CAF+CM: 0.4 ± 0.3 mm; CAF+XDM: 0.4 ± 0.2 mm) compared to the control group (CAF: 0.0 ± 0.1 mm; P < 0.05).

CONCLUSION

The CAF, CAF+CM, and CAF+XDM treatments each provided similar results in the treatment of single gingival recessions. The addition of either CM or XDM to CAF increases the GT.

Mesenchymal Stromal Cells Enhance Vascularization and Epithelialization within 7 Days after Gingival Augmentation with Collagen Matrices in Rabbits

Soft gingival tissue deficiency remains a severe problem leading to postoperative recession, peri-implantitis, and bone resorption. The use of collagen matrices does not always lead to complete rebuilding of the gingiva volume. The application of mesenchymal stromal cells (MSCs) simultaneously with collagen materials represents a promising approach for the restoration of soft gingival tissues. However, short-term effects of MSCs-enriched collagen grafts after gingival augmentation have not yet been studied properly. Mucograft and Mucoderm matrices were implanted in rabbits (n = 12) simultaneously with the intraoperative injection of rabbit bone marrow-derived mesenchymal stromal cells (BM-MSCs) or without cells. Collagen matrices were implanted under the flap or by the surface technique without intentional primary closure. The samples were harvested seven days after implantation, histological staining with hematoxylin and eosin, and immunohistochemical staining for VEGF, IGF1, and TGF were performed. The use of Mucoderm led to better augmentation outcomes on day 7 compared with Mucograft (p < 0.0001). Gingival augmentation in combination with the local administration of BM-MSCs led to better regeneration of the soft gingival tissues independently of the type of implanted collagen matrices (p < 0.0001). Furthermore, injection of BM-MSCs significantly enhanced gingival vascularization and epithelization with a clear positive correlation between vascular growth and epithelial response. Administration of BM-MSCs in combination with various collagen materials may potentially improve gingiva regeneration.

Is the postoperative discomfort after connective tissue harvesting from the palate influenced by the use of a bipolar coagulator? A randomized controlled trial

Objectives

This study aimed to determine the effect of the use of a bipolar coagulator on postoperative pain and complications when used during connective tissue harvesting from the palate.

Material and methods

A randomized controlled clinical trial was conducted with 57 sequential patients requiring a connective tissue graft for periodontal or implant surgery. All samples were harvested superficially and de‐epithelized outside the mouth. The patients were randomly allocated to two groups: in one group, the bipolar coagulator was used before suturing to control bleeding, and in the other group, the coagulator was not used. The surgeon was unaware of the randomization until the end of the harvesting phase. Self‐reported maximum pain, number of painkillers used, bleeding events, emergency visits at the clinic were recorded 7 days after surgery.

Results

Fifty patients were randomized and treated (seven were excluded for different reasons). The mean harvested area was 75.24 mm² (SD, 33.96), and the mean thickness of the samples was 2.47 mm (SD, 0.75). The mean self‐reported pain value on the visual analog scale was 3.37 (SD, 2.30), and the mean number of pain medications used was 7.1 (SD, 6.60). Seven patients made an emergency visit each, and 17 delayed bleeding events were reported by 15 patients. No statistically significant differences were reported in postoperative pain, postoperative bleeding, and emergency visit to the clinic between the groups that did and did not use the bipolar coagulator. When smoking habits were taken into consideration, the number of pain medications was higher among male smokers and older smokers than among male non‐smokers and younger smokers. This study was not able to find a relationship between harvested sample dimension or thickness and postoperative discomfort.

Conclusions

The bipolar coagulator can be used during connective tissue harvesting from the palate to control bleeding without influencing postoperative pain.

Histomorphometric Comparison between Two Types of Acellular Dermal Matrix Grafts: A Mini Pig Animal Model Study

Acellular dermal matrix grafts (ADMG) have been used as soft tissue graft substitutes for autografts in periodontal plastic surgical procedures. They have benefits like avoiding a second surgical site and patient morbidity that have been associated with autografts, but there is limited evidence available on their tissue response and wound healing process. This histomorphometric animal model study was carried out in mini pigs and it aimed to compare the two types of ADMG materials of porcine derivative with a control group through observation of parameters like epithelial and Keratinized layer thickness, angiogenesis, cellularity, matrix resorption, and inflammatory infiltrate. The surgical technique involved punctures on the edentulous areas stripping the epithelial tissue and exposing the underlying connective tissue, placement of the ADMGs in the appropriate control and test sites. Following this, gingival biopsies were procured at three different time intervals of 15, 45, and 90 days. There were significant differences in epithelial and Keratinized layer thickness among the three groups. This study concluded that there was no clear consensus on which graft material was superior but it gave an insight into the tissue response and wound healing process associated with the graft materials.

Free Gingival Graft and Collagen Matrix Revascularization in an Enoral Open Wound Situation

PURPOSE

Vestibuloplasty with free gingival grafting is a frequently performed surgical procedure to generate sufficient keratinized mucosa (KM) around dental implants. Avascular porcine collagen matrices (CM) have been proclaimed to be sufficient substitutes as alternatives to free gingival grafts (FGGs). However, the process of graft integration and vascularization is still incompletely understood.

METHODS

In 18 patients a vestibuloplasty in the lower edentulous jaw situation was performed during implant exposure, either with FGGs from the palate or a porcine CM (mucoderm). Tissue perfusion of the soft tissue grafts was measured using laser-doppler-spectrophotometer intraoperatively and on postoperative days 2, 5, 10, 30 and between days 60 and 90. With graft perfusion expressed by oxygen saturation [SO2%], the relative amount of hemoglobin [rHb], blood flow, and velocity [AU] was detected and compared between groups and the surrounding mucosa.

RESULTS

Healing was uneventful in both groups, with mature KM around dental implants after healing. Blood flow and velocity significantly increased until postoperative day 10, comparable to perfusion values of the surrounded mucosa. Intergroup comparisons revelated no significant differences concerning the flow between CM and FGGs. Oxygen saturation also significantly increased within the first 5 postoperative days in both groups. Hemoglobin content did not show any differences during the investigated period.

CONCLUSIONS

The perfusion mainly progresses within the first postoperative week with only minimal further detectable alterations until the final investigation, comparable in both groups. Although integration of FGGs (revascularized) and the CM (new tissue formation) is biologically different, both transplants show comparable perfusion patterns, leading to sufficient KM.

Volumetric soft tissue alterations in the early healing phase after peri- implant soft tissue contour augmentation with a porcine collagen matrix versus the autologous connective tissue graft: A controlled clinical trial

AIM

This study evaluates the early volumetric changes after buccal soft tissue contour augmentation around implants with a porcine collagen matrix (CM) vs. the subepithelial connective tissue graft (SCTG) from the palate.

MATERIALS AND METHODS

14 patients were enrolled after early implant placement with simultaneous contour augmentation and persistent buccal tissue deficits. At implant exposure, buccal soft tissues were thickened with the CM (n = 7) or the SCTG (n = 7). Impressions were taken before and after surgery, after ten days, one, three and six months. Impressions were digitized and augmented regions 3D evaluated (soft tissue volume (mm³ , %)/thickness (mm)).

RESULTS

Volume increase (mm³ ) after 6 months was 19.56 ± 8.95 mm³ (CM) and 61.75 ± 52.69 mm³ (SCTG) (insignificant, p = .058). In percentage, this was a volume loss of the initially augmented soft tissue volume (100%) of 81.76% in the CM group and 56.39% in the SCTG group (6 months). The mean soft tissue thickness increase (mm) in the buccal contour after 6 months was 0.30 ± 0.16 mm (CM) and 0.80 ± 0.61 mm (SCTG) (insignificant, p = .071).

CONCLUSION

The early healing phase is associated with a significant volume loss of the soft tissues. The SCTG shows insignificant superiority compared to the CM.

Current Insight of Collagen Biomatrix for Gingival Recession: An Evidence-Based Systematic Review

Collagen (Col) is a naturally available material and is widely used in the tissue engineering and medical field owing to its high biocompatibility and malleability. Promising results on the use of Col were observed in the periodontal application and many attempts have been carried out to inculcate Col for gingival recession (GR). Col is found to be an excellent provisional bioscaffold for the current treatment in GR. Therefore, the aim of this paper is to scrutinize an overview of the reported Col effect focusing on in vitro, in vivo, and clinical trials in GR application. A comprehensive literature search was performed using EBSCOhost, Science Direct, Springer Link, and Medline & Ovid databases to identify the potential articles on particular topics. The search query was accomplished based on the Boolean operators involving keywords such as (1) collagen OR scaffold OR hybrid scaffold OR biomaterial AND (2) gingiva recession OR tissue regeneration OR dental tissue OR healing mechanism OR gingiva. Only articles published from 2015 onwards were selected for further analysis. This review includes the physicochemical properties of Col scaffold and the outcome for GR. The comprehensive literature search retrieved a total of 3077 articles using the appropriate keywords. However, on the basis of the inclusion and exclusion criteria, only 15 articles were chosen for further review. The results from these articles indicated that Col promoted gingival tissue regeneration for GR healing. Therefore, this systematic review recapitulated that Col enhances regeneration of gingival tissue either through a slow or rapid process with no sign of cytotoxicity or adverse effect.

State of the Art on Biomaterials for Soft Tissue Augmentation in the Oral Cavity. Part I: Natural Polymers-Based Biomaterials

Oral soft tissue thickening or grafting procedures are often necessary to cover tooth recession, re-establish an adequate width of keratinized tissue, correct mucogingival deformities improving esthetics, prepare a site for an implant or prosthetics, for ridge preservation procedures, and soft tissue contouring around dental implants. Gingival recession and root or implant exposure are commonly associated and have led to mucogingival deficiencies that have traditionally been treated with free gingival grafts and autogenous soft tissue grafts. The latter represents the gold standard in acquiring a functionally adequate zone of keratinized attached gingiva. However, soft tissue substitutes are more usually employed because they lessen morbidity and abbreviate surgical time. This review is aimed at assessing oral soft tissue augmentation techniques and biomaterials used from existing literature, principally concerning scaffolds from both human and animal-based tissue derivatives matrices. In order to avoid the use of human donor tissue, the xenogenic collagen matrices are proposed for soft tissue augmentation. In general, all of them have provided the remodeling processes and enhanced the formation of new connective tissue within the matrix body.

State of the Art on Biomaterials for Soft Tissue Augmentation in the Oral Cavity. Part II: Synthetic Polymers-Based Biomaterials

Most of the polymers used as biomaterials for scaffolds are naturally occurring, synthetic biodegradable, and synthetic non-biodegradable polymers. Since synthetic polymers can be adapted for obtaining singular desired characteristics by applying various fabrication techniques, their use has increased in the biomedical field, in dentistry in particular. The manufacturing methods of these new structures include many processes, such as electrospinning, 3D printing, or the use of computer-aided design/computer-aided manufacturing (CAD/CAM). Synthetic polymers show several drawbacks that can limit their use in clinical applications, such as the lack of cellular recognition, biodegradability, and biocompatibility. Moreover, concerning biodegradable polymers, the time for matrix resorption is not predictable, and non-resorbable matrices are preferred for soft tissue augmentation in the oral cavity. This review aimed to determine a new biomaterial to offset the present shortcomings in the oral environment. Researchers have recently proposed a novel non-resorbable composite membrane manufactured via electrospinning that has allowed obtaining remarkable in vivo outcomes concerning angiogenesis and immunomodulation throughout the polarization of macrophages. A prototype of the protocol for in vitro and in vivo experimentation with hydrogels is explained in order to encourage innovation into the development of promising biomaterials for soft tissue augmentation in the near future.

Coronally advanced flap with connective tissue graft or xenogeneic acellular dermal matrix in the treatment of multiple gingival recessions: A split-mouth randomized clinical trial

OBJECTIVE

To evaluate the clinical efficacy of xenogeneic acellular dermal matrix (XADM) or connective tissue graft (CTG) combined with modified-coronally advanced flap (M-CAF) in the treatment of multiple gingival recessions.

MATERIALS AND METHODS

Twelve participants with bilateral MGRs (multiple gingival recession) (82 gingival recessions) randomly received XADM (test group, 41 teeth) on one side and subepithelial CTG (control group, 41 teeth) on the other side in conjunction with M-CAF in the same session and completed the 18-months study period. Recession depth (RD), recession width (RW), keratinized tissue width (KTW), probing depth (PD), and clinical attachment level (CAL) were recorded at baseline, and 6-, 18-months postoperatively.

RESULTS

PD was significantly higher in the test group at 18-months (P < .05). PD in the test group was also significantly higher at 6- and 18-months compared to baseline (P < .05). RD and RW were significantly lower at 6- and 18-months compared to baseline in both groups (P < .05) and both parameters were significantly higher in the test group at 18-months (P < .05). Percentage of teeth with complete root coverage in the test and control groups were similar at 6-months (78% and 70.7%, respectively) and at 18-months (both 87.8%) (P > .05).

CONCLUSION

Within the limits of the study, M-CAF combined with XADM or CTG seems to be similarly effective in RD reduction of class I and II MGRs at least in the short term. Soft tissue shrinkage and increase in PD may be observed with XADM, while; CTG seems to provide stable clinical outcomes for 18-months follow-up.

CLINICAL SIGNIFICANCE

Even though the CTG and XADM in conjunction with M-CAF may provide similar RD reduction in class I and II multiple gingival recessions in the short term. CTGs may be superior in terms of soft tissue shrinkage and PD values.