Soft tissue volume alterations after connective tissue grafting at teeth: the subepithelial autologous connective tissue graft versus a porcine collagen matrix - a pre-clinical volumetric analysis

Soft Tissue Augmentation by Electrospun Membranes embedded With Nano-Hydroxyapatite: Histologic and Volumetric Analyses

PURPOSE

The aim of this study was to assess the histologic and volumetric alteration in gingival tissues following grafting with electrospinning collagen membranes blended with nanophased hydroxyapatite (nHA) on the buccal side of canine teeth.

METHODS

Four adult beagle dogs underwent hemisecting of the mandibular premolars, followed by the extraction of the mesial roots. Soft tissue augmentations were randomly conducted with collagen membranes composed of poly (L-Lactic-co-caprolactone) and porcine fibrinogen (PLCL/F-Fg), PLCL/F-Fg membranes blended with nHA (PLCL/F-Fg/nHA), or a sham-operated control. The animals were sacrificed at 12 weeks post-surgery and received volumetric analyses. Histological examinations at the meantime were carried out at five different depths below the crest (0, 1.5, 2.5, 3.5 and 5.5 mm).

RESULTS

Histological examinations showed a statistically significant increase in buccal gingival thickness between PLCL/F-Fg/20%nHA and PLCL/F-Fg (3.82 ± 1.56mm vs 1.78 ± 0.20mm (at 3.5 mm); 4.23 ± 0.63mm vs 1.80 ± 0.58mm (at 5.5 mm)) as well as between PLCL/F-Fg/20%nHA and PLCL/F-Fg/10%nHA (4.23 ± 0.63mm vs 1.97 ± 0.73mm (at 5.5 mm)). Volumetric analyses showed a statistically significant decrease in volume reduction between PLCL/F-Fg/20%nHA and PLCL/F-Fg (4.46 ± 2.75mm3 vs 10.27 ± 4.77mm3) as well as between PLCL/F-Fg/20%nHA and PLCL/F-Fg/10%nHA (4.46 ± 2.75mm3 vs 10.57 ± 2.88mm3).

CONCLUSION

PLCL/F-Fg/20%nHA membranes demonstrated effectiveness in the gingival thickness augmentation on the buccal side of canine teeth at 12 weeks postsurgery. The electrospinning collagen membranes blended with nHA rendered an alternative treatment for soft tissue volume augmentations at the pontic site.

3D-Analysis of Peri-Implant Soft Tissue Gain With Collagen Matrix and Connective Tissue Graft: A Randomized Control Trial

OBJECTIVES

To compare the efficacy of the connective tissue graft (SCTG) and the collagen matrix (VXCM) in terms of soft tissue gain at the buccal site around a single implant.

METHODS

The study was designed as a randomized, controlled clinical trial. This trial was registered in ClinicalTrial.gov with the identifier NCT05870774 and is accessible under the following link: https://clinicaltrials.gov/study/NCT05870774?term=NCT05870774&rank=1. This clinical trial was not registered prior to participant recruitment and randomization. Patients with a single tooth gap and horizontal soft tissue thickness deficiency were enrolled in the study. Sites were randomly allocated to the control (SCTG) or test group (VXCM: Geistlich Fibro-Gide, Geistlich Pharma AG, Wolhusen, Switzerland) to augment buccal soft tissue thickness. The primary outcome was soft tissue gain 3 months post-op. Secondary outcomes included soft tissue gain 6 months post-op, the pink aesthetic score (PES), and patient-reported outcome measures (PROMs).

RESULTS

Patients' recruitment started on 28 October 2021 and ended on 25 December 2022. Thirty-two patients were enrolled and subjected to intervention. Sixteen patients were included per group. Three months post-op, soft tissue gain at the buccal site was 1.77 ± 0.61 mm in the VXCM group and 1.26 ± 0.41 mm in the SCTG group (p = 0.0003). Six months post-op, soft tissue gain was 1.11 ± 0.44 mm in the VXCM group and 1.43 ± 0.81 mm in the SCTG group (p = 0.0459). PROMs, including pain perception, favored the VXCM group. SCTG demonstrated favored results in PES.

CONCLUSION

SCTG remains the gold standard for increasing soft tissue thickness in terms of the clinical result.

Long-term assessment of a modified tunneling technique for root coverage in lower anterior gingival recession: a retrospective study

PURPOSE

Root coverage (RC) procedures require long-term evaluation. This study assessed the clinical validity and long-term stability of a modified tunneling technique for lower anterior gingival recession (GR) using a subepithelial connective tissue graft (SCTG) and a volume-stable collagen matrix.

METHODS

Across 39 patients, 66 mandibular incisors with ≥1.0 mm of GR were examined before and after RC surgery. Clinical photographs documenting the results of RC were taken at baseline (T₀) and the most recent follow-up visit (Tl). Impressions were obtained either at baseline (T₀) or 3 weeks later (T₃). The recession depth, Miller classification, and rates of RC and complete root coverage (CRC) were assessed.

RESULTS

This study analyzed 66 GR sites across 39 patients, with an average follow-up period of 41.3 months. Overall, the mean RC achieved was 86.2%±15.7%. Among single recessions, the RC was 85.2%±25.6% for Miller class I, 91.5%±10.4% for class II, and 79.2%±18.3% for class III. Regarding multiple recessions, the RC was 85.1%±16.2% for Miller class I, 87.0%±12.5% for class II, and 89.8%±16.0% for class III. By Miller classification, the RC was 85.1%±16.8% for class I, 88.7%±11.6% for class II, and 85.8%±17.3% for class III. Furthermore, the RC varied by follow-up duration: 72.5%±15.1% at 12 months, 90.1%±12.6% at 25-36 months, 89.0%±16.7% at 37-48 months, 91.10%±9.88% at 49-60 months, and 97.6±4.79% for longer than 61 months, with 77.8% of the last group achieving CRC. RC also differed based on the initial recession depth, at 88.0%±16.8% for 1-3 mm, 83.1%±14.1% for 3-6 mm, and 80.2%±5.04% for depths exceeding 6 mm.

CONCLUSIONS

A modified tunneling technique, utilizing SCTG and a volume-stable collagen matrix, appears to represent a reliable option for the long-term management of GR in the lower anterior region, even in cases involving multiple Miller class III GRs.

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.

The activin/BMP-2 chimera AB204 promotes periodontal tissue regeneration in a buccal dehiscence model: a pilot study

PURPOSE

A combination of activin and bone morphogenetic protein-2 (BMP-2), termed AB204, has been shown to improve osteogenic potential with fewer side effects than BMP-2 alone. This study was performed to evaluate the effect of AB204 on periodontal tissue regeneration in a dog buccal dehiscence model.

METHODS

Buccal dehiscence defects were created on the maxillary premolars (P1, P2, and P3) of 6 mongrel dogs. After 5 weeks, the dogs were randomly assigned to 1 of 3 groups: the control, collagen matrix (CM), and CM/AB204 groups. Grafting procedures were then performed. The dogs were sacrificed 8 weeks after the grafting procedure, and volumetric and histological analyses were conducted.

RESULTS

The thickness of the buccal gingiva in the CM/AB204 group was greater than those in the other groups at 2 weeks (P<0.05). The ridge width in the AB204/CM group exceeded the width in the other groups at 4 and 8 weeks; however, the difference was not statistically significant. Histological analysis revealed that the CM/AB204 group demonstrated the formation of new bone surrounded by newly formed periodontal ligament and cementum (P=0.035).

CONCLUSIONS

The combined application of CM and AB204 shows promise in facilitating the regeneration of periodontal attachment, including the formation of new bone, cementum, and periodontal ligament.

Investigation of Morphological Changes of the Soft Tissue in the Aesthetic Zone: A 3D Virtual Analysis after Conventional Tooth Extraction and Benex® Extraction

BACKGROUND

Postoperative resorption of hard and soft tissues occurs as a consequence of tooth extraction. The Benex®-Control extractor allows minimally invasive extraction of the tooth without causing pronounced iatrogenic trauma. The aim of this study was to verify whether the resorption of the tissues after extraction can be reduced by using the Benex® system compared to the conventional extraction method.

METHODS

Postoperative intraoral scans were superimposed after surgery (t0), after 7 days (t1), after 14 days (t2), after 30 days (t3), after 60 days (t4), and after 90 days (t5) within the two groups (study n = 14, control n = 16), and defined regions of interest (ROIs) (1-8) and volume changes were analyzed. In addition, the influence of gingival thickness and the thickness of the labial cortical plate was investigated.

RESULTS

The greatest decrease in volume was observed in both groups in ROI3, although there was no significant difference observed between the groups. In the presence of an adjacent tooth, there was less volume loss in the affected ROIs (1, 2 and 7, 8). The thickness of the gingiva and the bony lamella did not significantly influence the change in volume.

CONCLUSIONS

Due to the small cohort, the results are limited, and the hypothesis is rejected.

The adjunctive effect of polydeoxyribonucleotide on bone formation in alveolar ridge preservation: A pre-clinical in vivo study

AIM

This study investigated the adjunctive effect of polydeoxyribonucleotide (PDRN) on bone formation in alveolar ridge preservation (ARP) sockets.

MATERIALS AND METHODS

Both mandibular second, third and fourth premolars of eight beagle dogs were randomly divided into ARP and ARP/PDRN groups. Following tooth extraction, ARP procedures were conducted using collagenized alloplastic graft material and bilayer collagen membrane soaked with normal saline (ARP group) or PDRN (ARP/PDRN group) for 10 min before application. Both groups were also randomly allocated to 2-, 4- or 12-week healing subgroups. The primary endpoint of this study was to compare histomorphometric differences between ARP and ARP/PDRN. The secondary endpoints of this study were to compare micro-CT analysis and three-dimensional volumetric measurement between the two groups.

RESULTS

In the histomorphometric analysis, the ARP/PDRN group exhibited greater new bone formation at coronal, middle and total position compared with the ARP group at 2-week healing. The number of newly formed blood vessels was higher in the ARP/PDRN group than in the ARP group at 2- and 4-week healing. In micro-CT analysis, the mean new bone volume/total bone volume between ARP and ARP/PDRN was statistically significant at 2-week healing. Ridge volume alterations were significantly decreased in the ARP/PDRN group during entire healing time compared with the ARP group, especially on the buccal side.

CONCLUSIONS

The application of PDRN in ARP might provide additional benefits for early bone regeneration and maintenance of buccal ridge volume.

Effectiveness of a collagen matrix seal and xenograft in alveolar ridge preservation: an experimental study in dogs

Majority of previous studies on alveolar ridge preservation (ARP) used collagen membranes as barrier membranes, and further evidence for ARP in dehiscent extraction sockets with a deproteinized bovine bone mineral (DBBM) and matrix is needed. The aim of this study is to assess the impact of non-cross linked collagen membranes (membrane) and crosslinked collagen matrices (matrix) on ARP using DBBM in extraction sockets with buccal dehiscence. In six mongrel dogs, the mesial roots of three mandibular premolars (P2, P3, and P4) were extracted 1 month after dehiscence defect induction. Two experimental groups were randomly assigned: (1) DBBM with a membrane (DBBM/membrane group) and (2) DBBM with a matrix (DBBM/matrix group). Three-dimensional (3D) volumetric, microcomputed tomography (μCT), and histologic analyses were performed to assess the ridge preservation. Both groups were effective to maintain the ridge width (p > 0.05), and the DBBM/matrix group showed more favorable soft tissue regeneration and bone quality in the histological analysis (p = 0.05). Based on these results, DBBM/matrix could be better choice for ARP in cases of buccal dehiscence defects.

Effect of polydeoxyribonucleotide with xenogeneic collagen matrix on gingival phenotype modification: a pilot preclinical study

PURPOSE

To investigate the effect of xenogeneic collagen matrix (XCM) with polydeoxyribonucleotide (PDRN) for gingival phenotype modification compared to autogenous connective tissue graft.

METHODS

Five mongrel dogs were used in this study. Box-type gingival defects were surgically created bilaterally on the maxillary canines 8 weeks before gingival augmentation. A coronally positioned flap was performed with either a subepithelial connective tissue graft (SCTG) or XCM with PDRN (2.0 mg/mL). The animals were sacrificed after 12 weeks. Intraoral scanning was performed for soft tissue analysis, and histologic and histomorphometric analyses were performed.

RESULTS

One animal exhibited wound dehiscence, leaving 4 for analysis. Superimposition of STL files revealed no significant difference in the amount of gingival thickness increase (ranging from 0.69±0.25 mm to 0.80±0.31 mm in group SCTG and from 0.48±0.25 mm to 0.85±0.44 mm in group PDRN; P>0.05). Histomorphometric analysis showed no significant differences between the groups in supracrestal gingival tissue height, keratinized tissue height, tissue thickness, and rete peg density (P>0.05).

CONCLUSIONS

XCM soaked with PDRN yielded comparable gingival augmentation to SCTG.

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.

In vitro and in vivo evaluation of a modified porcine acellular dermal matrix for soft tissue augmentation

OBJECTIVES

To evaluate the effects of a modified porcine acellular dermal matrix (P-ADM), subepithelial connective tissue graft (SCTG) and other commercial bovine acellular dermal matrix membrane materials (B-ADM) on gingival soft tissue augmentation in the oral esthetic zone.

MATERIAL AND METHODS

The characteristics of P-ADM were observed by scanning electron microscope (SEM), Hematoxylin and eosin (H&E) and Masson's trichrome staining (Masson staining). The biocompatibility of P-ADM was verified by CCK8, phalloidin and living/dead cell staining. Beagle dog models were constructed and the thickness of gingiva was analyzed by the intraoral scanner. The morphology was observed by H&E and Masson staining.

RESULTS

Scanning electron microscopy, H&E and Masson staining showed that the P-ADM was mainly composed of collagen fibers, with no component of nuclear. The results of CCK8, phalloidin and living/dead cell staining indicated that the P-ADM had good cytocompatibility and no cytotoxicity. Human gingival fibroblasts were able to adhere and stretch on the surface of the material with pseudopodia. The SCTG group outperformed the B-ADM and P-ADM groups in terms of effectiveness, according to the analysis of digital oral scanning data at various time points following incremental soft tissue surgery. Compared with the B-ADM group, the effect of soft tissue increment was better in the P-ADM group.

CONCLUSIONS

P-ADM, as a biocompatible biomaterial, can be used as an alternative biomaterial for oral soft tissue thickening. However, the results of this study need to be verified by more clinical trials.

Recombinant human platelet-derived growth factor improves root coverage of a collagen matrix for multiple adjacent gingival recessions: A triple-blinded, randomized, placebo-controlled trial

AIM

To evaluate the efficacy of recombinant human platelet-derived growth factor (rhPDGF)-BB combined with a cross-linked collagen matrix (CCM) for the treatment of multiple adjacent gingival recession type 1 defects (MAGRs) in combination with the coronally advanced flap (CAF).

MATERIALS AND METHODS

Thirty patients were enrolled in this triple-blind, randomized, placebo-controlled trial and treated with either CAF + CCM + rhPDGF, or CAF + CCM + saline. The primary outcome was mean root coverage (mRC) at 6 months. Complete root coverage, gain in gingival thickness (GT), keratinized tissue width, volumetric and ultrasonographic changes, and patient-reported outcome measures were also assessed. Mixed-modelling regression analyses were used for statistical comparisons.

RESULTS

At 6 months, the mRC of the CCM + rhPDGF and CCM alone groups were 88.25% and 77.72%, respectively (p = .02). A significant gain in GT was consistently observed for both treatment arms, and more so for the patients receiving the matrix containing rhPDGF through time (0.51 vs. 0.80 mm, on average, p = .01). The rhPDGF + CCM treated patients presented greater volume gain, higher soft tissue thickness, and a superior aesthetic score.

CONCLUSION

rhPDGF enhances the clinical, volumetric, and aesthetic outcomes of MAGRs above the results achieved with CAF + CCM alone (ClinicalTrials.gov NCT04462237).

Clinical Comparison of the Volumetric Changes in Single Pontic Site Development through Connective Tissue Grafting Using Modified Pouch Technique versus Pouch Technique in the Maxillary Esthetic Zone: A Randomized Controlled Clinical Trial

Aim

The aim is to compare the volumetric changes between pouch technique versus the modified pouch technique in pontic site development using connective tissue graft in patients that have Seibert class I ridge defects in the maxillary esthetic zone. Methodology. This randomized, controlled, double-blinded, parallel-grouped clinical trial included sixteen patients with a single pontic site in the maxillary esthetic area presenting Seibert Class I ridge defects. Patients were randomly assigned into two equal groups: test group (n: 8) received soft tissue augmentation with connective tissue graft using the modified pouch technique and control group (n: 8) received soft tissue augmentation with connective tissue graft using pouch technique. The volumetric evaluation was carried out by taking impressions at baseline, 3 and 6 months after the surgery. Keratinized tissue thickness was also measured at baseline, 3 and 6 months after the surgery. Visual analogue scale (VAS) was recorded by the patients at day 3, day 7, and day 14 after the surgery.

Results

The test group had more increase in soft tissue volume than the control group at baseline, 3 months, and 6 months. The keratinized tissue width at baseline in the test group had a higher value than that of the control group. At 3 months, both groups had the same mean value, while at 6 months, the test group had a higher value than the control group. Regarding postoperative pain, the visual analogue scale shown at day 3 in the test group had a higher value than that of the control group, while at day 7, the control group had a higher value than the test group. At day 14, both groups had the same mean value.

Conclusions

Soft tissue augmentation using both the traditional pouch technique and the modified pouch technique led to successful soft tissue volume augmentation in pontic site development in Seibert Class I ridge defects with no statistically significant difference between the two techniques.

Use of Xenogenic Collagen Matrices in Peri-Implant Soft Tissue Volume Augmentation: A Critical Review on the Current Evidence and New Technique Presentation

Plastic peri-implant surgical procedures aiming to increase soft tissue volume around dental implants have long been well-described. These are represented by: pedicle soft tissue grafts (rotational flap procedures and advanced flap procedures) and free soft tissue grafts (epithelialized, also called free gingival graft (FGG), and non-epithelialized, also called, connective tissue graft (CTG) or a combination of both. To bypass the drawback connected with autologous grafts harvesting, xenogenic collagen matrices (XCM)s and collagen-based matrices derived from porcine dermis (PDXCM)s have been introduced, as an alternative, in plastic peri-implant procedures. Aim: This review is aimed to evaluate and to critically analyze the available evidence on the effectiveness of XCMs and PDXCMs in soft tissue volume augmentation around dental implants. Moreover, a clinical case with a new soft tissue grafting procedure technique (Guided Soft Tissue Regeneration, GSTR) is presented. Material and Methods: An electronic search was performed on the MEDLINE database, SCOPUS, Cochrane Library and Web of Science. The electronic search provided a total of 133 articles. One hundred and twenty-eight not meeting the inclusion criteria were excluded. Seven articles of human randomized clinical trials were selected. A total number of 108 patients were treated with CTG, and 110 patients with XCM. Results: in peri-implant soft tissue augmentation procedures, XCMs seem an effective alternative to CTGs, associated with lower patient morbidity and lower operative times.

Peri-implant soft-tissue esthetic outcome after immediate implant placement in conjunction with xenogeneic acellular dermal matrix or connective tissue graft: A randomized controlled clinical study

OBJECTIVES

This randomized comparative study evaluated the clinical esthetic outcome of the peri-implant mucosa following extraction and immediate implant placement in conjunction with anorganic bovine bone mineral (ABBM) and the use of a porcine acellular dermal matrix (pADM) versus an autogenous connective tissue graft (CTG) in the anterior maxilla.

MATERIALS AND METHODS

Twenty patients (11 men, 9 women) with a mean age of 48,9 years (range 21-72) were included in the study and randomly assigned to either the test (pADM) or control group (CTG). They underwent extraction and immediate implant placement together with ABBM for socket grafting and either pADM or CTG for soft tissue augmentation. Twelve months after implant placement color measurements of the peri-implant mucosa and a reference tooth were performed using a spectophotometer and the color difference (ΔE) was calculated. The overall esthetic appearance of the peri-implant soft tissue was evaluated using the Pink Esthetic Score (PES). Statistical analysis was performed using Student's T-Test, the alpha was set to 0.05.

RESULTS

All implants received osseointegration and were restored. The mean color difference of the peri-implant mucosa 1 year after surgery amounted ΔE 4.06 ± 1.6 for the test group (pADM) and ΔE 3.58 ± 1.36 mm for the control group (CTG), showing no statistically significant difference (p = 0.47). The mean PES of the pADM group was 11.4 ± 1.4 and for the CTG group 10.7 ± 1.5, showing no statistically significant difference (p = 0.29).

CONCLUSION

Twelve months after surgery, a porcine acellular dermal matrix for soft tissue augmentation in conjunction with immediate implant placement showed no difference in the overall esthetic appearance regarding color match and Pink Esthetic Score in comparison to autogenous soft tissue graft.

CLINICAL SIGNIFICANCE

Connective tissue grafts have become a standard in order to enhance the soft tissue quality and esthetic appearance in immediate implant placement. The use of new biomaterials like porcine acellular dermal matrices may avoid the need to harvest autogenous grafts resulting in simplified treatment and less postoperative morbidity.

Modified tunneling technique for root coverage of anterior mandible using minimal soft tissue harvesting and volume-stable collagen matrix: a retrospective study

Purpose

In this study, we aimed to evaluate the clinical validity of the modified tunneling technique using minimal soft tissue harvesting and volume-stable collagen matrix in the anterior mandible.

Methods

In total, 27 anterior mandibular teeth and palatal donor sites in 17 patients with ≥1 mm of gingival recession (GR) were analyzed before and after root coverage. For the recipient sites, vertical vestibular incisions were made in the interdental area and a subperiosteal tunnel was created with an elevator. After both sides of the marginal gingiva were tied to one another, a prepared connective tissue graft and volume-stable collagen matrix were inserted through the vestibular vertical incision and were fixed with resorbable suture material. The root coverage results of the recipient site were measured at baseline (T₀), 3 weeks (T₃), 12 weeks (T₁₂), and the latest visit (T_l). For palatal donor sites, a free gingival graft from a pre-decided area avoiding the main trunk of the greater palatine artery was harvested using a prefabricated surgical template at a depth of 2 mm after de-epithelization using a rotating bur. In each patient, the clinical and volumetric changes at the donor sites between T₀ and T₃ were measured.

Results

During an average follow-up of 14.5 months, teeth with denuded root lengths of 1–3 mm (n=12), 3–6 mm (n=11), and >6 mm (n=2) achieved root coverage of 97.01%±7.65%, 86.70%±5.66%, and 82.53%±1.39%, respectively. Miller classification I (n=12), II (n=10), and III (n=3) teeth showed mean coverage rates of 97.01%±7.65%, 86.91%±5.90%, and 83.19%±1.62%, respectively. At the donor sites, an average defect depth of 1.41 mm (70.5%) recovered in 3 weeks, and the wounds were epithelized completely in all cases.

Conclusions

The modified tunneling technique in this study is a promising treatment modality for overcoming GR in the anterior mandible.

Porcine Acellular Dermal Matrix: An Alternative to Connective Tissue Graft-A Narrative Review

Porcine acellular dermal matrix has recently been introduced in dentistry as an alternative to the gold standard connective tissue graft especially for the use in gingival recession treatments and soft tissue augmentation in implant surgery. Connective tissue grafts are inconvenient and require a second surgical site leading to greater morbidity, longer surgical procedures, and a more painful postoperative phase for the patient. Other options such as allografts have ethical concerns and are less available in Europe. Thus, dental professionals have sought other techniques and materials. Porcine acellular dermal matrix results in periodontal recession treatment with a gain in recession coverage as well as increased keratinized tissue and soft tissue augmentation. This leads to more keratinized mucosa and greater tissue thickness. Many studies have been published using collagen matrices, but a few strictly use porcine acellular dermal matrix, which have been studied in prospective randomized clinical trials with a large number of patients and longer follow-up periods (more than 5 years). Nevertheless, more data are needed to confirm that the porcine acellular dermal matrix is a suitable alternative although its favourable results to date suggest a positive future.

In Vitro Biodegradation Pattern of Collagen Matrices for Soft Tissue Augmentation

Collagen matrices have become a great alternative to the use of connective tissue grafts for soft tissue augmentation procedures. One of the main problems with these matrices is their volume instability and rapid degradation. This study has been designed with the objective of examining the degradation of three matrices over time. For this purpose, pieces of 10 × 10 mm² of Fibro-Gide, Mucograft and Mucoderm were submitted to three different degradation tests-(1) hydrolytic degradation in phosphate buffer solution (PBS); (2) enzyme resistance, using a 0.25% porcine trypsin solution; and (3) bacterial collagenase resistance (Clostridium histolyticum)-over different immersion periods of up to 50 days. Weight measurements were performed with an analytic microbalance. Thickness was measured with a digital caliper. A stereomicroscope was used to obtain the matrices' images. ANOVA and Student-Newman-Keuls tests were used for mean comparisons (p < 0.05), except when analyzing differences between time-points within the same matrix and solution, where pair-wise comparisons were applied (p < 0.001). Fibro-Gide attained the highest resistance to all degradation challenges. The bacterial collagenase solution was shown to constitute the most aggressive test as all matrices presented 100% degradation before 14 days of storage.

Peri-implant tissue augmentation by volume-stable collagen matrix transplantation: a study of dog mandibles

The aim of this study was to investigate histologically the amount of peri-implant tissue augmentation after volume-stable porcine collagen matrix transplantation. Six male beagle dogs were used in the experiment. P2, P4, and M1 distal roots were extracted under general anesthesia. After 6 months, implants were placed in the same sites, and volume-stable porcine collagen matrix transplantation was performed. Impressions were taken at 1 and 2 weeks and at 1, 2, and 3 months after transplantation. The dogs were euthanized at 3 months, and their mandibles were removed and scanned using micro-computed tomography. Standard Triangulated Language data were also obtained. Using preoperative models as a reference, the data for all time points were compared, and changes in the thickness of the cross-section of the implant sites were measured. The model created at 3 months was then compared with the mandible data, and the thickness of collected peri-implant soft tissue was measured under optical microscopy. Increased thickness was found at some of the sites on the buccal side. Regarding the peri-implant soft tissue, the thickness of the measured sites on the buccal side was significantly increased at 3 months in the experimental group. Histological observations of the internal structures of the tissue in the experimental group revealed irregular collagen fibers and a remnant collagen matrix. Endogenous tissue was observed within the collagen matrix, indicating good fusion with the surrounding autologous tissue. These results suggest that volume-stable porcine collagen matrix transplantation promotes peri-implant tissue augmentation on the buccal side.

Impact of Cross-Linking of Collagen Matrices on Tissue Regeneration in a Rabbit Calvarial Bone Defect

The cross-linking of collagen matrices (Cl_CM) may provide volume-stable enhanced defect regeneration when compared to non-cross-linked matrices (Ncl_CM). The aim of the present study was to investigate the bone forming potential of collagen matrices (CMs) and the effects of cross-linking CMs in a rabbit calvaria defect model. (1) Empty controls (n = 6), (2) Ncl_CM (n = 8), and (3) Cl_CM (n = 8) were selected to be observed for the healing in 10 mm critical-sized calvarial bone defects. The potential for the bone as well as the connective tissue formation were evaluated by micro-CT and histomorphometry at three months post-surgery. There were no statistically significant differences in terms of new bone volume in the defects between the groups. However, the Cl_CM induced significantly greater fibrous tissue regeneration (5.29 ± 1.57 mm²) when compared to the controls (3.51 ± 0.93 mm²) by histomorphometry. The remnants of collagen fibers with immune cells, including macrophages and giant cells, were occasionally observed in the Cl_CM group but not in the Ncl_CM group. In conclusion, the cross-linking of collagen did not influence the potential for bone formation. Nevertheless, Cl_CM might be advantageous for the maintenance of fibrous tissue volume without disturbing bone formation in the defects.

Collagen Matrix vs. Autogenous Connective Tissue Graft for Soft Tissue Augmentation: A Systematic Review and Meta-Analysis

Soft tissues have been shown to be critical for the maintenance of both teeth and implants. Currently, regenerative soft tissue techniques propose the use of collagen matrices, which can avoid the drawbacks derived from the obtainment of autogenous tissue graft. A systematic review and meta-analysis were conducted to ascertain the efficacy of collagen matrices (CM) compared to autogenous connective tissue graft (CTG) to improve soft tissue dimensions. An electronic and manual literature searches were performed to identify randomized clinical trials (RCT) or controlled clinical trials (CCT) that compared CTG and CM. Pooled data of width of keratinized tissue (KT) and mucosal thickness (MT) were collected and weighted means were calculated. Heterogeneity was determined using Higgins (I²). If I² > 50% a random-effects model was applied. Nineteen studies were included based on the eligibility criteria. When using CTG a higher MT gain (0.32 mm, ranging from 0.49 to 0.16 mm) was obtained than when employing CM. Similar result was obtained for the width of KT gain, that was 0.46 mm higher (ranging from 0.89 to 0.02 mm) when employing CTG. However, it can be stated that, although autogenous CTG achieves higher values, CM are an effective alternative in terms of total width of KT and MT gain.

Comparison between a xenogeneic dermal matrix and connective tissue graft for the treatment of multiple adjacent gingival recessions: a randomized controlled clinical trial

AIM

To compare the outcomes of modified coronally advanced flap (mCAF) combined with either xenogeneic dermal matrix (XDM) or connective tissue graft (CTG) for the treatment of multiple adjacent gingival recessions (MAGRs).

MATERIALS AND METHODS

Forty-two patients, in whom 130 maxillary (MAGRs) of type (RT1) were found, were randomly allocated to the two groups. Clinical, esthetic, and patient-centered outcomes were evaluated at baseline, 6, and 12 months post-treatment.

RESULT

Group CAF+ CTG exhibited a higher mean root coverage value (mRC) (91.79%) (primary outcome variable) than group CAF+XDM (80.19%) without statistically significant difference at 12 months (p=0.06). The control group also had significantly higher percentage of teeth in which complete root coverage (CRC) and mean gain of gingival thickness (GT) were achieved, than the test group (p<0.05). With respect to patient-centered outcomes, patients of the test group reported having experienced significantly less pain than those of the control group until 7 days (p<0.05). Both surgical approaches were capable of significantly decreasing dentin hypersensitivity (p<0.05). No difference between groups was found in the esthetic score analysis (p>0.05). Mean surgical time was lower in the test group (p<0.05).

CONCLUSION

The two treatments showed similar mRC. However, CAF+CTG was superior to CAF+XDM in providing CRC and in gaining GT. CAF+XDM demonstrated advantages over CAF+CTG with regard to patient morbidity and surgical time.

CLINICAL RELEVANCE

Application of XDM provided a better patient experience and shortened the time to recovery after coronally advanced flaps for coverage of multiple adjacent recessions. However, CTG resulted in improved percentages of complete root coverage.

TRIAL REGISTRATION

Brazilian Clinical Trials Registry (REBEC) number: RBR-974c9j.

Three-dimensional quantitative measurement of buccal augmented tissue with modified coronally advanced tunnel technique and de-epithelialized gingival graft: a prospective case series

BACKGROUND

The aim of this study is to investigate three-dimensional quantitative analysis of buccal augmented tissue alterations after surgery using a modified coronally advanced tunnel (MCAT) technique combined with a de-epithelialized gingival graft (DGG) within 1 year post-op, based on intraoral scanning.

METHODS

25 Cairo class I gingival recession defects were treated using an MCAT technique with DGG. Digital impressions were taken using an intraoral scanner at baseline, 2 weeks, 6 weeks, 3 months, and 1 year after the surgery. Three-dimensional quantitative measurements within 1 year were analyzed for buccal augmented tissue after surgery, including postoperative gingival height gain (GHG), area gain (GAG), volume gain (GVG) and mean thickness (GMT) of region of interest, as well as the tissue thickness change at 1, 2, and 3 mm (TTC1, TTC2, and TTC3) apical to the cemento-enamel junction.

RESULTS

Postoperative GHG, GAG, GVG, and GMT were distinctly encountered at 2 weeks post-op, then gradually decreased. At 1 year, GHG, GAG, GVG, and GMT were 2.211 ± 0.717 mm, 7.614 ± 2.511 mm2, 7.690 ± 4.335 mm3 and 0.965 ± 0.372 mm, respectively. Significant decreases were recorded between 6 weeks and 1 year in terms of GHG, GAG, and GVG. The GMT was sustained after 6 weeks with an increase of nearly 1 mm at 1 year. TTC1 and TTC2 yielded thicker tissue change than TTC3.

CONCLUSIONS

Three-dimensional quantitative measurements taken via intraoral scanning showed that buccal augmented tissue acquired via MCAT with DGG tends to be stable after 3 months post-op. Digital measurement can be applied in periodontal plastic surgery as a clinically feasible and non-invasive evaluation method for achieving volumetric outcomes.

TRIAL REGISTRATION

This study was retrospectively registered in the Chinese Clinical Trial Registry: ChiCTR1900026768. Date of registration: 21/10/2019.

Root coverage of multiple gingival recessions treated with coronally advanced flap associated with xenogeneic acellular dermal matrix or connective tissue graft: a 6-month split-mouth controlled and randomized clinical trial

OBJECTIVES

This study aimed to compare xenogeneic dermal matrix (XDM) to connective tissue graft (CTG) associated with coronally advanced flap (CAF) in treating Miller's class I and II (RT1) multiple gingival recession in a split-mouth randomized clinical trial.

MATERIALS AND METHODS

Fifteen patients with bilateral Miller's class I and II multiple recessions were selected. The patient's side receiving each treatment was randomly allocated to receive XDM or CTG. The clinical parameters were measured at baseline and 6 months of follow-up.

RESULTS

At 6 months, no significant difference in the root coverage (RC) (95.28 ± 6.89% for CTG and 92.68 ± 7.35% for XDM) and the keratinized tissue (KT) gain (0.91 ± 0.46 mm for CTG and 0.74 ± 0.39 mm for XDM) was observed between groups (p > 0.05). The CTG group presented higher complete root coverage (CRC) than XDM (60% and 33%, respectively) (p = 0.045). Multiple logistic regression indicated that the XDM (p = 0.01) and the XDM and KT interaction (p = 0.02) negatively interfered in the CRC. A 1-mm increase in the baseline KT when using XDM increases almost 6 times the chance of achieving CRC, and XDM reached a similar CRC probability to CTG when the receptor area presented at least 2 mm of KT.

CONCLUSIONS

Both treatments were effective for treating multiple gingival recession; similar KT gain, GR reduction, and RC were obtained for CTG and XDM, while CTG promoted higher CRC than XDM. Moreover, the amount of KT at baseline was determinant for CRC when treating multiple gingival recession with XDM.

CLINICAL RELEVANCE

XDM produces limited CRC in sites with a reduced amount of KT.

TRIAL REGISTRATION

Brazilian Clinical Trials Registry (REBEC) number RBR-56NZQ6.

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.

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.

Augmentation of soft tissue volume at pontic sites: a comparison between a cross-linked and a non-cross-linked collagen matrix

AIM

To assess histopathological and histomorphometric outcomes of soft tissue volume augmentation procedures at pontic sites using a volume-stable cross-linked collagen matrix (VCMX) and a non-cross-linked collagen matrix (XCM).

MATERIALS AND METHODS

In twelve adult beagle dogs, the mandibular premolars and first molar were hemisected and the mesial root extracted. Soft tissue augmentation was randomly performed using VCMX, XCM, or a sham-operated control. Sacrifice was performed after 4, 8, and 26 weeks. Non-decalcified sections were analyzed for histopathologic and histomorphometric measurements at four different levels below the crest (1.5, 2.5, 3.5, and 5.5 mm).

RESULTS

Group VCMX presented a greater overall amount of soft tissue at all healing time points, more pronounced fibroblast ingrowth, vascularization, and a substantial new collagen deposition. Over time, group XCM demonstrated faster signs of degradation compared with group VCMX. Four weeks after augmentation, group VCMX yielded a higher mean ridge width compared with groups XCM (2.22 mm VCMX, 0.89 mm XCM (at 2.5 mm); 2.05 mm VCMX, 0.80 mm XCM (at 3.5 mm) p < 0.05) and sham (0.59 mm sham (at 1.5 mm); 0.48 mm (at 2.5 mm); 0.44 mm (at 3.5 mm) p < 0.05). After healing periods of 8 and 26 weeks, measurements in group VCMX remained significantly higher compared with group sham both at 8 weeks (levels of 1.5 mm, 2.5 mm and 5.5 mm) and at 26 weeks (levels of 1.5 mm, 3.5 mm and 5.5 mm) (p < 0.05).

CONCLUSION

The use of a cross-linked collagen matrix resulted in a greater and more stable ridge width over time compared with control groups.

CLINICAL RELEVANCE

Soft tissue volume augmentation at pontic sites is more effective when using a cross-linked compared with a non-cross-linked collagen matrix.

Effects of soft tissue grafting prior to orthodontic treatment on preventing gingival recession in dogs

PURPOSE

This study was conducted to assess the efficacy of prophylactic gingival grafting in the mandibular anterior labial area for preventing orthodontically induced gingival recession.

METHODS

Eight mongrel dogs received gingival graft surgery at the first (I1) and third (I3) mandibular incisors on both sides based on the following group allocation: AT group (autogenous connective tissue graft on I1), AT-control group (contralateral side in the AT group), CM group (xenogeneic cross-linked collagen matrix graft on I3) and CM-control group (contralateral side in the CM group). At 4 weeks after surgery, 6 incisors were splinted and proclined for 4 weeks, followed by 16 weeks of retention. At 24 weeks after surgery, casts were made and compared with those made before surgery, and radiographic and histomorphometric analyses were performed.

RESULTS

Despite the proclination of the incisal tip (by approximately 3 mm), labial gingival recession did not occur. The labial gingiva was thicker in the AT group (1.85±0.50 mm vs. 1.76±0.45 mm, P>0.05) and CM group (1.90±0.33 mm vs. 1.79±0.20 mm, P>0.05) than in their respective control groups.

CONCLUSIONS

The level of the labial gingival margin did not change following labial proclination of incisors in dogs. Both the AT and CM groups showed enhanced gingival thickness.

A 3-Year Prospective Study on a Porcine-Derived Acellular Collagen Matrix to Re-Establish Convexity at the Buccal Aspect of Single Implants in the Molar Area: A Volumetric Analysis

Background: Xenogeneic soft tissue substitutes are currently being investigated as an alternative to subepithelial connective tissue grafts (CTG) with the intention to avoid postoperative morbidity associated with autologous grafting. The aim of the present study was to volumetrically evaluate the effectiveness and mid-long-term stability of a porcine-derived collagen matrix (PDCM) (Mucoderm^®, Botiss gmbh, Berlin, Germany) in increasing soft tissue volume at the buccal aspect of molar implant sites. Methods: Periodontally healthy non-smoking patients with a single tooth gap in the molar area were selected for a prospective case series. All sites had a bucco-oral bone dimension of at least 8 mm and demonstrated a horizontal alveolar defect. A wide diameter implant was placed under the elevated buccal flap and a PDCM was applied. The primary outcome was the linear increase in buccal soft tissue profile (BSP) within a well-defined area of interest. This was performed with designated software (SMOP; Swissmeda AG, Zurich, Switzerland) on the basis of superimposed digitalized study casts taken before surgery (T0), immediately after surgery (T1), at three months (T2), one year (T3) and three years (T4). Secondary outcomes were alveolar process deficiency and clinical parameters. Results: Fourteen out of 15 treated patients attended the three-year re-assessment (four females; mean age 51.4 years). Mean linear increase in BSP at T1 was 1.53 mm (p = 0.001). The PDCM showed substantial resorption at T2 (1.02 mm or 66.7%) (p = 0.001). Thereafter, a 0.66 mm volume gain was observed (p = 0.030), possibly due to the installation of a permanent crown displacing the soft tissues to the buccal aspect. This resulted in a linear increase in BSP of 1.17 mm (76.5%) at T4. Alveolar process deficiency significantly reduced over time (p = 0.004). However, 50% of patients still demonstrated a slight (6/14) or obvious (1/14) alveolar process deficiency at study termination. Implants demonstrated healthy clinical conditions. Conclusions: The PDCM demonstrated marked resorption during the early stages of healing. Due to the matrix thickening the tissues, and the permanent crown displacing the tissues, 76.5% of the initial increase in BSP could be maintained over a three-year period. Half of the patients failed to show perfect soft tissue convexity at the buccal aspect.

Root coverage using coronally advanced flap with porcine-derived acellular dermal matrix or subepithelial connective tissue graft: a randomized controlled clinical trial

OBJECTIVE

The aim of this study is to investigate the use of a porcine-derived acellular dermal matrix (MD) in root coverage procedures combined with extended coronally positioned flap (eCAF), in comparison to the subepithelial connective tissue graft (SCTG) associated with the eCAF.

MATERIAL AND METHODS

Eighteen adult patients presenting bilateral type 1 gingival recession were randomly assigned to SCTG or MD groups. Clinical and patient-based outcomes were recorded at 3 and 6 months after the surgical procedure.

RESULTS

Both groups showed a significant reduction in the mean recession height of 3.33 ± 0.89 mm to 1.24 ± 1.10 mm (MD) and 3.21 ± 0.8 mm to 0.83 ± 0.86 mm (SCTG) without difference between groups. Six patients in the test group and eight in the control group obtained complete root coverage. The keratinized tissue height and thickness (KTT) showed a significant increase after 3 and 6 months in both groups. The average KTT gains were 0.39 ± 0.4 mm (MD) and 0.51 ± 0.5 mm (SCTG) (p < 0.05). Performing multivariate analysis suggests that MD addition to coronally advanced flaps may be similar to SCTG.

CONCLUSION

The MD had similar results in comparison to SCTG and in the context of reducing patient morbidity it can be used as an alternative for the treatment of gingival recessions.

CLINICAL RELEVANCE

The SCTG is the gold standard therapy for root coverage. The MD has been widely used in mucogingival surgery as a substitute for SCTG and proposed similar results. A substitute is very important for clinicians and patients. It will give a better postoperative and possibilities to treat multiples recession. (Clinicaltrials.gov Identifier: NCT03675334).

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

AIM

To compare 10-month histological and immunohistological outcomes after soft tissue thickening around teeth with a porcine collagen matrix (CM) versus a subepithelial connective tissue graft (SCTG).

MATERIAL AND METHODS

In eight beagle dogs, soft tissue thickening of the buccal gingiva of upper canines was performed with the SCTG or the CM. Connective tissue thickness (CTT) was histomorphometrically measured in the augmented regions. The augmented connective tissues were also histologically characterized and the collagen I and vascular endothelial growth factor (VEGF) expressions immunohistologically quantified.

RESULTS

CTT significantly differed between groups (SCTG: 1.32 mm ± 0.44 mm; CM: 1.06 mm ± 0.27 mm; p = .008). Descriptive histological analyses revealed mature connective tissue that did not differ between groups. Immunohistological quantification of collagen I and VEGF expressions in the connective tissue also revealed no significant inter-group differences (collagen I: SCTG, 32.64% ± 7.09% vs. CM, 30.57% ± 7.83%; VEGF: SCTG, 39.06% ± 7.27% vs. CM, 37.15% ± 9.80%).

CONCLUSION

SCTG is superior to CM with regard to CTT in this experimental model. The CM and the SCTG lead to comparable connective tissue quality ten months after connective tissue thickening.

Soft tissue augmentation applying a collagenated porcine dermal matrix during second stage surgery: A prospective multicenter case series

BACKGROUND

The achievement and preservation of an adequate amount of soft tissue around implants is a critical factor for the prognosis of the treatment.

PURPOSE

To evaluate the effectiveness of a porcine dermal matrix applied during second stage implant surgery for horizontal soft tissue augmentation and preservation of dimensional stability.

MATERIALS AND METHODS

Twenty patients (mean age 50.2 ± 11.9 [SD] years) candidate to implant therapy and requiring soft tissue augmentation were recruited in four centers. Augmentation was performed in 24 cases. A porcine dermal matrix was placed into a buccal split-thickness pouch during uncovering surgery. Silicone impressions were taken before surgery (T0), 2 weeks later at suture removal (T2), 6 months (T3), and 24 months (T4) post augmentation. Dimensional changes of soft tissue were evaluated using superimposition of digitalized study casts.

RESULTS

Nineteen patients (23 implants) could be evaluated at 6 months and 13 patients (17 implants) at 24 months. After 6-month follow-up, there was a significant dimensional gain respect to baseline, averaging 0.83 ± 0.64 mm (P < .01). This did not change significantly at 24 months (0.77 ± 0.65 mm, P = .19). The gain was >0.5 mm in 65.2% and 64.7% of the cases, respectively. Soft tissue shrinkage averaged 34.2% ± 77.0% from T2 to T3 (P < .01) and did not change thereafter (P = .39). Shrinkage was more consistent in the posterior mandible than in the maxilla, but not significantly (P = .23 at 6-month and .36 at 24-month). No adverse events occurred.

CONCLUSION

Within the limitations of this prospective case series, the use of a porcine dermal matrix may provide consistent soft tissue augmentation that maintains up to 24-month follow-up, although graft shrinkage may occur in the first 6 months, depending on the location of surgery.

Soft tissue substitutes to increase gingival thickness: Histologic and volumetric analyses in dogs

OBJECTIVES

To evaluate the histologic and volumetric changes of gingival tissues following grafting with collagen-based matrices at labial aspect of teeth in canines.

MATERIALS AND METHODS

Gingival augmentation was performed in the mandibular incisor area using two types of xenogeneic cross-linked collagen matrices (CCMs), bovine CCM for BCCM group and porcine CCM for PCCM group, whereas the contralateral sides remained untreated (B-control group and P-control group). Descriptive histology, histometric and volumetric analyses were performed after 12 weeks. For statistical comparison between each test group and respective control group, paired t test was used for histometric analysis, and repeated-measured analysis of variance was used for volumetric analysis (p < 0.05).

RESULTS

An increased number of rete pegs and an enhanced formation of new blood vessels were observed at both grafted sites compared to the corresponding control sites. There was statistically significant gain of horizontal thickness only in BCCM group (1.36 ± 0.27 mm vs. 1.26 ± 0.34 mm; p < 0.05) compared to the B-control groups.

CONCLUSION

BCCM was effective for gingival augmentation in terms of horizontal thickness at the labial aspect of teeth at 12 weeks post-surgery.