Long-term outcomes after vestibuloplasty with a porcine collagen matrix (Mucograft® ) versus the free gingival graft: a comparative prospective clinical trial

Dimensional changes in free gingival grafts at implant sites in the reconstructed mandible: a retrospective study

OBJECTIVE

To evaluate the dimensional changes in free gingival grafts (FGG) at implant sites in mandibular reconstruction patients.

METHODS

Patients who received FGG 4 months after implant placement in the reconstructed mandible with no keratinized mucosa (KM) present were invited for re-examination after 36.7 ± 16.8 months (3.06 ± 1.4 years). Immediately after graft extraction (T0), graft width (GW), graft length (GL), graft thickness (GT), graft dimension (GD), and vertical bone height were documented. Re-examination (T1) included clinical examinations (GW, GL, GD, peri-implant probing depths, and modified Sulcus Bleeding Index), radiographic examination (marginal bone level), and medical chart review.

RESULTS

Twenty patients and 62 implants (47 in fibula flaps and 15 in iliac flaps) were included. A significant decrease in GW (51.8%), GL (19.2%), and GD (60.2%), were found between T0 and T1 (p < .001). The univariate analysis showed that GW change was not significantly associated with reconstruction technique, baseline GL, baseline GT, baseline GD, implant location, or type of prosthesis. Implant survival rate of 100% was observed at follow-up.

CONCLUSIONS

Within the limitations of the study, free gingival grafts at implant sites in the reconstructed mandible undergo dimensional change that result in a reduction of approximately 60% of the original graft dimension. Graft width decreased over 50%.

CLINICAL RELEVANCE

FGG is the standard of care intervention for increasing the amount of KM around implants. This study was the first to evaluate the dimensional change in FGG at implant sites in mandibular reconstruction patients after a medium-term follow-up.

CLINICAL TRIAL REGISTRATION

Clinical trial registration is not applicable as this study comprehends a retrospective analysis.

A Strip Free Gingival Graft and a Xenogeneic Collagen Matrix to Increase Keratinized Tissue After Vertical Bone Augmentation

After vertical bone augmentation (VBA) surgery, loss of both keratinized tissue (KT) and vestibule depth (VD) take place. This article evaluated KT gain, patient satisfaction, and aesthetic outcomes after a modified apically repositioned flap (ARF) in combination with a strip-free gingival graft (FGG) harvested from the palate and a xenogeneic collagen matrix (XCM) to correct mucogingival distortion (MGD) after VBA. This technique minimizes patient morbidity by reducing the need for extensive masticatory mucosa grafts. The study included 12 patients with ≤3 mm KT after vertical augmentation procedures. Keratinized tissue gain and tissue thickness were measured. Patient morbidity and aesthetic outcomes were also evaluated. Twenty-four months after surgery, significant VD gain was observed, obtaining a vertical KT augmentation of 5.38 ± 2.06 mm, although tissue thickness increase was only 0.42 ± 0.42mm. Regarding patient satisfaction, aesthetic results evaluating tissue color and texture were satisfactory; the pain was slight, obtaining a score of 2.10 ± 1.13 out of 10, measured using a Visual Analogue Scale (VAS). The present retrospective case series study shows that using an apically repositioned flap combined with a strip FGG and an XCM might offer a valid means of achieving KT gain.

Xenogeneic Collagen Matrix Versus Free Gingival Graft for Augmenting Peri-Implant Keratinized Mucosa Around Dental Implants: A Systematic Review and Meta-Analysis

OBJECTIVES

There is a growing evidence to suggest augmenting peri-implant keratinized mucosa in the presence of ≤ 2 mm of keratinized mucosa. However, the most appropriate surgical technique and augmentation materials have yet to be defined. The aim of this systematic review and meta-analyses was to evaluate the clinical and patient-reported outcomes of augmenting keratinized mucosa around implants using free gingival graft (FGG) versus xenogeneic collagen matrix (XCM) before commencing prosthetic implant treatment.

MATERIAL AND METHODS

Electronic databases were searched to identify observational studies comparing implant sites augmented with FGG to those augmented with XCM. The risk of bias was assessed using the Cochrane Collaboration's Risk of Bias tool.

RESULTS

Six studies with 174 participants were included in the present review. Of these, 87 participants had FGG, whereas the remaining participants had XCM. At 6 months, sites augmented with FGG were associated with less changes in the gained width of peri-implant keratinized mucosa compared to those augmented with XCM (mean difference 1.06; 95% confidence interval -0.01 to 2.13; p = 0.05). The difference, however, was marginally significant. The difference between the two groups in changes in thickness of peri-implant keratinized mucosa at 6 months was statistically significantly in favor of FGG. On the other hand, XCM had significantly shorter surgical time, lower postoperative pain score, and higher color match compared to FGG.

CONCLUSIONS

Within the limitation of this review, the augmentation of keratinized mucosa using FGG before the placement of the final prosthesis may have short-term positive effects on soft tissue thickness. XCM might be considered in aesthetically demanding implant sites and where patient comfort or shorter surgical time is a priority. The evidence support, however, is of low to moderate certainty; therefore, further studies are needed to support the findings of the present review.

A combination technique of strip free gingival grafts and xenogeneic collagen matrix in augmenting keratinized mucosa around dental implants: a single-arm clinical trial

BACKGROUND

The aim of this study was to assess the outcomes of the combination technique of strip free gingival grafts (SFGG) and xenogeneic collagen matrix (XCM) in augmenting the width of keratinized mucosa (KMW) around dental implants, and compare its efficacy with the historical control group (FGG).

METHODS

Thirteen patients with at least one site with KMW ≤ 2 mm after implant surgery were included and received SFGG in combination with XCM. Another thirteen patients with the same inclusion and exclusion criteria from the previous trial received FGG alone. The same outcomes as the previous trial were evaluated. KMW, thickness of keratinized mucosa (KMT), gingival index (GI) and probing depth (PD) were measured at baseline, 2 and 6 months. Postoperative pain, patient satisfaction and aesthetic outcomes were also assessed.

RESULTS

At 6 months after surgery, the combination technique could attain 3.3 ± 1.6 mm of KMW. No significant change could be detected in GI or PD at 6 months compared to those at 2 months (p > 0.05). The postoperative pain and patient satisfaction in VAS were 2.6 ± 1.2 and 9.5 ± 1.2. The total score of aesthetic outcomes was 3.8 ± 1.2. In the historical FGG group, 4.6 ± 1.6 mm of KMW was reported at 6 months, and the total score of aesthetic outcomes was higher than the combination technique (4.8 ± 0.7 vs. 3.8 ± 1.2, p < 0.05).

CONCLUSIONS

The combination technique of SFGG and XCM could increase KMW and maintain peri-implant health. However, this combination technique was associated with inferior augmentation and aesthetic outcomes compared with FGG alone.

TRIAL REGISTRATION

This clinical trial was registered in the Chinese Clinical Trial Registry with registration number ChiCTR2200057670 on 15/03/2022.

Autogenous graft versus collagen matrices for peri-implant soft tissue augmentation. A systematic review and network meta-analysis

OBJECTIVE

The primary objective of this review is to compare autogenous soft tissue grafts (connective tissue graft - CTG and free gingival graft-FGG) with different type of matrices (acellular dermal matrix-ADM, xenograft collagen matrix-XCM, volume-stable collagen matrix-VCMX) used to increase peri-implant soft tissues.

MATERIALS AND METHODS

A search on electronic databases was performed to identify randomized and non-randomized controlled trials (RCTs and CCTs, respectively) with either parallel or split-mouth design, and treating ≥ 10 patients. A network meta-analysis (NMA) was used to compare different matrices. Soft tissue thickness dimensional changes and keratinized width (KMW) changes were the primary outcome measures. The secondary outcomes were to evaluate: a) PROMs; b) volumetric changes; c) surgical operating time; and d) different periodontal measurements.

RESULTS

A total of 23 studies were included in the qualitative analysis, and 16 studies (11 RCTs and 5 CCTs) in the quantitative analysis. A total of N = 573 sites were evaluated for NMA. CTG resulted the best material for increasing peri-implant soft tissue thickness, at 180 and 360 days after surgery. The use of an ADM showed good results for buccal thickness increase, primarily in the first three months after surgery. Vestibuloplasty + FGG resulted in the most effective technique for peri-implant KMW augmentation, after 180 days.

CONCLUSIONS

While CTG demonstrated better performance in all the comparison and FGG showed to be the best graft to increase keratinized mucosa up to 90 days, ADM and VCMX may be used to increase soft tissue horizontal thickness with lower patients' morbidity.

LIMITATIONS

The limits of this NMA are the following: a) limited number of included studies; b) high heterogeneity among them (number of patients, treatment sites, surgical techniques, outcome measures, and follow-ups).

CLINICAL RELEVANCE

Many studies compared the efficacy of autogenous and non-autogenous grafts in terms of gingival thickness, volume, and keratinized width increase. However, there is still not clear overall evidence on this topic. This NMA helps clinicians to choose the right material in different peri-implant soft tissue procedures. Recommendations for future studies are mandatory.

Dermal Matrix Graft Effects on Facial Growth in a Veau-Wardill-Kilner Palatoplasty Model: An Experimental Study in Rats

The primary goal of palatoplasty is the restoration of normal speech, that can be aimed by, among many procedures, lengthening the palate through the pushback technique; one of its complications is abnormal maxillary growth. The main factor affecting facial growth in CLP patients is believed by many to be the palatoplasty-due to the large scar retraction resulting from some surgical techniques. The non-crosslinked two-layer bioabsorbable collagen matrix Mucograft™ (Geistlich Pharma AG, Wolhusen, Switzerland) is a potential tool to aid in wound closure in a second-intention healing situation.

The objective of this work was to test the use of an acellular dermal matrix (Mucograft®) in an experimental model of Veau-Wardill-Kilner palatoplasty, as a tool to reduce scar retraction of the denuded palatine mucosa.

Twenty-four 3-week-old male Wistar rats were used. The animals were randomly divided into two groups. In the control group, an excision was made with bone exposure in the palate, simulating the defect left in the Veau-Wardill-Kilner palatoplasty. In the intervention group, the same procedure was performed, and the area of denuded palatine bone was treated with a bioabsorbable collagen matrix (Mucograft®). For data collection, 9 weeks after surgery (12 weeks of life), the animals were euthanized by excessive anesthetic dosage. Maxillary growth, macroscopic appearance of the scar, pain, and bleeding were evaluated.

There were significant statistical differences between the groups for palate length growth (7.6 mm + -0.38 mm vs 5.5 mm + -0.36 mm, P = .009) and for palate width growth (1.47 mm + -0.8 mm vs -0.09 mm + -0.55 mm, P = .001), favoring dermal matrix group compared to controls. Whereas for pain and bleeding, there were no differences between the groups.

The use of dermal matrix in rats with an area of bone denudation on the palate increases maxillary length and width growth patterns. Besides, it does not increase pain, bleeding, or post-operative complications.

Augmentation of keratinized tissue using autogenous soft-tissue grafts and collagen-based soft-tissue substitutes at teeth and dental implants: Histological findings in a pilot pre-clinical study

AIM

To histomorphometrically assess three treatment modalities for gaining keratinized tissue (KT) at teeth and at dental implants.

MATERIALS AND METHODS

In five dogs, the distal roots of the mandibular second, third and fourth premolars were extracted. Dental implants were placed at the distal root areas 2 months later. After another 2 months, KT augmentation was performed at both distal (implants) and at mesial root (teeth) areas in the presence (wKT groups) or absence (w/oKT groups) of a KT band at the mucosal/gingival level. Three treatment modalities were applied randomly: apically positioned flap only (APF), free gingival grafts (FGGs) and xenogeneic collagen matrices (XCMs). A combination of the above produced six groups. Two months later, tissue sections were harvested and analysed histomorphometrically.

RESULTS

The median KT height and length were greatest at implants with FGG in both wKT (3.7 and 5.1 mm, respectively) and w/oKT groups (3.7 and 4.6 mm), and at teeth with FGG in wKT groups (3.7 and 6.1 mm) and with APF in the w/oKT groups (3.9 and 4.4 mm). The XCM and APF produced more favourable results at teeth than at implants.

CONCLUSIONS

FGG was advantageous in gaining KT, especially at implants.

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.

Novel Technique to Reconstruct Peri-Implant Keratinised Mucosa Width Using Xenogeneic Dermal Matrix. Clinical Case Series

Reconstruction of sufficient buccal peri-implant keratinised mucosa width (PIKM-W) is reported to reduce the symptoms of peri-implantitis. In order to reduce the drawbacks of autogenous graft harvesting, we investigated a novel porcine dermal matrix (XDM, mucoderm®) using a modified surgical technique for augmentation of PIKM-W. Twenty-four patients were recruited with insufficient (<2 mm) PIKM-W. After split thickness flap preparation, the XDM was trimmed, rehydrated and tightly attached to the recipient periosteal bed using modified internal/external horizontal periosteal mattress sutures via secondary wound healing. Change of the PIKM-W and dimension of the graft remodelling were evaluated at 6 and 12 months postoperatively. The mean PIKM-W changed from 0.42 ± 0.47 to 3.17 ± 1.21 mm at 6 M and to 2.36 ± 1.34 mm at 12 M in the maxilla and from 0.29 ± 0.45 mm to 1.58 ± 1.44 mm at 6 M and to 1.08 ± 1.07 mm at 12 M in the mandible. Graft dimensions decreased by 67.7 ± 11.8% and 81.6 ± 16.6% at 6 M, and continued to 75.9 ± 13.9% and 87.4 ± 12.3% at 12 M, in the maxilla and mandible, respectively. Clinical parameters showed statistically significant intra- and intergroup differences between the baseline and 6 and 12 months (p < 0.05). The present technique using the XDM was safe and successfully reconstructed PIKM-W in both arches. The XDM alone seems to be a suitable alternative to autograft for PIKM-W augmentation in the maxilla.

Digitally designed stent-assisted soft-tissue management after jaw reconstruction: a prospective cohort study

OBJECTIVES

A digitally designed stent was invented to assist vestibuloplasty and free gingival graft (FGG) after jaw reconstruction. This study aimed to compare the effects of conventional soft-tissue management comprising vestibuloplasty combined with FGG and modified soft-tissue management using a digitally designed stent on the vestibular sulcus depth (VD), keratinised-tissue width (KTW) and peri-implant tissue health in patients undergoing jaw reconstruction.

MATERIALS AND METHODS

This prospective cohort study enrolled patients who underwent jaw reconstruction using a fibular flap, iliac flap, or onlay bone graft followed by implant-supported rehabilitation at the Peking University School and Hospital of Stomatology between May 2019 and July 2022. Patients in the stent group received digitally designed stents following vestibuloplasty combined with FGG for peri-implant soft-tissue management. Patients in the control group underwent a conventional vestibuloplasty combined with FGG. VD and KTW were evaluated immediately after implant loading (T2) and 1 year after implant loading (T3), and the atrophy rates of VD and KTW were calculated. Peri-implant clinical parameters were evaluated at T3. Comparisons between the groups were performed using the Mann-Whitney U test. The effects of age, sex, primary disease, reconstruction type, reconstructed jaw and the number and location of implants on VD and KTW were evaluated using linear regression analysis.

RESULTS

There were no significant differences in the atrophy rates of VD and KTW between the stent and control groups at T2 and T3 (both P ≥ 0.05). There were no significant differences in peri-implant clinical parameters between the stent and control groups at T3 (P ≥ 0.05). Reconstruction type, location of implants and primary disease influenced VD, and reconstruction type and age influenced KTW.

CONCLUSIONS

There was no significant difference in the maintenance of VD and KTW after jaw reconstruction between soft-tissue management using a digitally designed stent and the conventional method. Further, digitally designed stents do not affect peri-implant tissue health.

CLINICAL RELEVANCE

Digitally designed stents can simplify clinical procedures without adverse effects on peri-implant tissue health, but they do not promote keratinized mucosa augmentation and vestibuloplasty.

The quality of life after keratinized mucosa augmentation around dental implants using xenogenic collagen matrix with or without stent

BACKGROUND

The substitution of missing teeth with implants is a dependable and anticipated therapeutic approach. Despite numerous studies affirming long-term success rates, there exists a spectrum of potential biological and aesthetic complications.

OBJECTIVE

The primary objective of this study was to assess patient responses subsequent to surgical interventions, with a specific emphasis on the utilization of xenogenic collagen matrix (XCM), both with and without the application of a stent secured over healing abutments, in the context of keratinized gingival mucosa augmentation. The principal aim was to evaluate and draw comparisons between the clinical outcomes resulting from these two procedural approaches, with a particular focus on critical parameters encompassing post-operative complications, patient comfort, and the overall efficacy in achieving successful keratinized tissue augmentation.

METHODS

Sixty patients were selected for this study. The patients were divided into three groups: A, B, and a control group, with each group comprising 20 participants. We used XCM in experimental group A, XCM covered with surgical stent in experimental group B, and free gingival graft (FGG) in the control group. After the surgical procedure, patients were required to complete a visual analogue scale (VAS) questionnaire for post-operative complications, and a quality of life (QOL) questionnaire on days 1, 3, and 7.

RESULTS

Patients in the experimental groups A and B demonstrated markedly improved outcomes when compared with the control group. Assessments conducted on days 1, 3, and 7 demonstrated diminished levels of pain, bleeding, and swelling in both experimental groups, with experimental group B showing the least discomfort. The incorporation of XCM, either with or without stents, was associated with a reduction in analgesic consumption, underscoring its favorable influence on post-operative comfort, notwithstanding the exception of halitosis in experimental group B.

CONCLUSION

Using XCM with or without a stent for keratinized tissue augmentation has better post-operative outcomes associated with reduced swelling, bleeding, and pain based on the QOL survey. This study provides data to support the clinical application of XCM and stents.

Electrophoretically Co-Deposited Collagen-Lactoferrin Membranes with Enhanced Pro-Regenerative Properties for Oral Soft Tissue Regeneration

The quality of soft tissue defect regeneration after dental surgeries largely determines their final success. Collagen membranes have been proposed for the healing of such defects, but in some cases, they do not guarantee a sufficient volume of the regenerated tissue and vascularization. For this purpose, lactoferrin, a protein with natural pro-regenerative, anti-inflammatory, and pro-angiogenic activity, can be added to collagen. In this article, we used a semipermeable barrier-assisted electrophoretic deposition (SBA-EPD) method for the production of collagen-lactoferrin membranes. The membrane structure was studied by SEM, and its mechanical properties were shown. The lactoferrin release kinetics were shown by ELISA within 75 h. When tested in vitro, we demonstrated that the collagen-lactoferrin membranes significantly increased the proliferation of keratinocytes (HaCaT) and fibroblasts (977hTERT) compared to blank collagen membranes. In vivo, on the vestibuloplasty and free gingival graft harvesting models, we showed that collagen-lactoferrin membranes decreased the wound inflammation and increased the healing rates and regeneration quality. In some parameters, collagen-lactoferrin membranes outperformed not only blank collagen membranes, but also the commercial membrane Mucograft®. Thus, we proved that collagen-lactoferrin membranes produced by the SBA-EPD method may be a valuable alternative to commercially used membranes for soft tissue regeneration in the oral cavity.

Implant-Prosthetic Rehabilitation of Mandibular Posttraumatic Severe Dentoalveolar Loss With a Reconstructive Staged Approach: A Clinical Report With 3-Year Follow-Up

This clinical report describes the oral rehabilitation of a 25-year-old male patient who lost the lower incisors, right canine, and a significant amount of anterior mandibular bony and soft tissue following severe dentoalveolar trauma due to a car accident. The patient's young age, anterior esthetic zone in the lower jaw, previous mandibular fracture, and extended bony and soft-tissue defect hindering ideal 3-dimensional implant placement oriented the therapeutic plan toward a staged approach, with several reconstructive surgical procedures before implant rehabilitation. The treatment involved deepening the labiobuccal vestibule and lingual sulcus to correct cicatricial shrinkage due to previous surgical fixation of the mandibular fracture, vertical guided bony augmentation to regenerate adequate volumes of bone, free gingival graft to achieve sufficient height and thickness of peri-implant soft tissues, and a prosthetic-driven surgical procedure to place the implants in a good functional and esthetic position. This therapeutic approach restored function and esthetics and achieved outcome stability at 3-year follow-up.

Technical Note on Simplified Free Gingival Graft Using Tack Fixation (sFGG)

Free gingival graft (FGG) is the gold standard procedure for the reliable augmentation of lost keratinized mucosa (KM) around dental implants. This conventional surgical approach has its drawbacks, including limitations in manipulation, the requirement for suturing, postoperative discomfort, and pain. This case report aimed to evaluate the efficacy of a simplified free gingival graft (sFGG) in addressing the issue of inadequate keratinized mucosa around dental implants. Fixation tacks were used to perform the sFGG procedure. Initially, a partial-thickness flap was created and apically repositioned. The gingival graft was harvested from the palate with a narrow profile and securely affixed to the recipient site using 5 mm long fixation tacks. Significant gains in keratinized mucosa were achieved and successfully maintained within 1 year. Consequently, the sFGG technique emerges as a simple and reliable treatment approach for managing inadequate keratinized mucosa around dental implants.

Properties of three collagen scaffolds in comparison with native connective tissue: an in-vitro study

PURPOSE

To evaluate collagen scaffolds (CS) in terms of their in vitro resorption behavior, surface structure, swelling behavior, and mechanical properties in physiologically simulated environments, compared with porcine native connective tissue.

MATERIALS AND METHODS

Three test materials-one porcine collagen matrix (p-CM), two acellular dermal matrices (porcine = p-ADM, allogenic = a-ADM)-and porcine native connective tissue (p-CTG) as a control material were examined for resorption in four solutions using a high-precision scale. The solutions were artificial saliva (AS) and simulated body fluid (SBF), both with and without collagenase (0.5 U/ml at 37 °C). In addition, the surface structures of CS were analyzed using a scanning electron microscope (SEM) before and after exposure to AS or SBF. The swelling behavior of CS was evaluated by measuring volume change and liquid absorption capacity in phosphate-buffered saline (PBS). Finally, the mechanical properties of CS and p-CTG were investigated using cyclic compression testing in PBS.

RESULTS

Solutions containing collagenase demonstrated high resorption rates with significant differences (p < 0.04) between the tested materials after 4 h, 8 h and 24 h, ranging from 54.1 to 100% after 24 h. SEM images revealed cross-linked collagen structures in all untreated specimens. Unlike a-ADM, the scaffolds of p-CM and p-ADM displayed a flake-like structure. The swelling ratio and fluid absorption capacity per area ranged from 13.4 to 25.5% among the test materials and showed following pattern: p-CM > a-ADM > p-ADM. P-CM exhibited higher elastic properties than p-ADM, whereas a-ADM, like p-CTG, were barely compressible and lost structural integrity under increasing pressure.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Collagen scaffolds vary significantly in their physical properties, such as resorption and swelling behavior and elastic properties, depending on their microstructure and composition. When clinically applied, these differences should be taken into consideration to achieve the desired outcomes.

Long-term evaluation of peri-implant keratinized mucosa stability after free epithelialized graft and keratinized mucosa shifting procedures: A retrospective study up to 13 years

OBJECTIVES

This study aimed to assess the risk of less than 2 mm keratinized mucosa (KM) width occurrence after free epithelialized graft (FEG) and keratinized mucosa shifting (KMS) procedures using survival analysis. In addition, KM dimensional changes were evaluated.

MATERIALS AND METHODS

This study included 76 implants in 36 patients with insufficient KM (<2 mm). The implants underwent either FEG or KMS procedures. The mid-buccal KM width was measured from surgery to the end of a one 13-year follow-up period.

RESULTS

Mean follow-up durations were 9.2 ± 3.9 years for FEG and 6.3 ± 4.2 years for KMS. Two implants in FEG and nine implants in KMS exhibited a KM width of less than 2 mm during follow-up. The hazard ratios for KMS compared to FEG were 6.48 (crude) and 6.54 (adjusted), both statistically significant (p < .05). The incidence rate of KMS (4.06%) was higher than that of FEG (0.63%), with an average incidence time of 3.38 years for KMS and 8.82 years for FEG post-surgery. FEG showed a significant shrinkage within 6 months (33% ± 22%), whereas KMS demonstrated a gradual decrease over 13 years (34% ± 25%). FEG exhibited significantly greater width change than KMS during a 5-year follow-up (p < .05).

CONCLUSIONS

FEG and KMS enhanced PIKM but exhibited different long-term reduction patterns. FEG demonstrated rapid shrinkage, while KMS displayed gradual and continuous reduction. Moreover, KMS presented a higher risk and incidence of KM width less than 2 mm compared to FEG.

Efficacy of a collagen matrix for soft tissue augmentation after implant placement compared to connective tissue grafts: A multicenter, noninferiority, randomized controlled trial

OBJECTIVES

To test whether soft tissue volume augmentation using a collagen matrix (VCMX) leads to noninferior results in terms of gain of mucosal thickness at single implant sites, compared to connective tissue grafts (SCTG).

METHODS

The study was designed as a multi-center randomized controlled clinical trial. Subjects in need of soft tissue volume augmentation at single tooth implant sites were consecutively recruited at nine centers. The deficient mucosal thickness at the implant sites (one per patient) was augmented by applying either a VCMX or a SCTG. Patients were examined at 120 days (abutment connection = primary endpoint), 180 days (final restoration), and 360 days (1-year after insertion of the final restoration). Outcome measures included: transmucosal probing of the mucosal thickness (crestal = primary outcome), profilometric measurements of the tissue volume, and patient-reported outcome measures (PROMs).

RESULTS

Out of the 88 patients, 79 attended the one-year follow-up. The median increase of the crestal mucosal thickness between pre-augmentation and 120 days was 0.3 ± 2.1 mm in the VCMX group and 0.8 ± 1.6 mm in the SCTG group (p = .455). Non-inferiority of the VCMX compared to the SCTG was not observed. The respective numbers at the buccal aspect amounted to 0.9 ± 2.0 mm (VCMX) and 1.1 ± 1.4 mm (SCTG; p = .431). PROMs including pain perception favored the VCMX group.

CONCLUSION

It remains inconclusive whether soft tissue augmentation using a VCMX is noninferior to SCTG in terms of crestal mucosal thickening at single implant sites. However, the use of collagen matrices favors PROMs especially pain perception, while achieving similar buccal volume gains along with comparable clinical and aesthetic parameters to SCTG.

Vestibuloplasty and its impact on the long-term survival and success of dental implants in irradiated and non-irradiated patients after head and neck tumor therapy: a retrospective study

OBJECTIVES

This study aimed to evaluate the influence of vestibuloplasty on the clinical success and survival of dental implants in head and neck tumor patients.

MATERIALS AND METHODS

A retrospective single-center study was conducted. All patients received surgical therapy of a tumor in the head or neck and underwent surgical therapy and, if necessary, radiotherapy/radiochemotherapy. Patients with compromised soft tissue conditions received vestibuloplasty using a split thickness skin graft and an implant-retained splint. Implant survival and success and the influence of vestibuloplasty, gender, radiotherapy, and localizations were evaluated.

RESULTS

A total of 247 dental implants in 49 patients (18 women and 31 men; mean age of 63.6 years) were evaluated. During the observation period, 6 implants were lost. The cumulative survival rate was 99.1% after 1 year and 3 years and 93.1% after 5 years for patients without vestibuloplasty, compared to a survival and success rate of 100% after 5 years in patients with vestibuloplasty. Additionally, patients with vestibuloplasty showed significantly lower peri-implant bone resorption rates after 5 years (mesial: p = 0.003; distal: p = 0.001).

CONCLUSION

This study demonstrates a high cumulative survival and success rate of dental implants after 5 years in head and neck tumor patients, irrespective of irradiation. Patients with vestibuloplasty showed a significantly higher rate of implant survival and significantly lower peri-implant bone resorption after 5 years.

CLINICAL RELEVANCE

Vestibuloplasty should always be considered and applied if required by the anatomical situations to achieve high implant survival/success rates in head and neck tumor patients.

Three-dimensional changes of a porcine collagen matrix and free gingival grafts for soft tissue augmentation to increase the width of keratinized tissue around dental implants: a randomized controlled clinical study

BACKGROUND

Emerging clinical data points to the relevance of the presence of keratinized tissue (KT). Although apically positioned flap/vestibuloplasty along with free gingival graft (FGG) is considered as a standard intervention for augmenting KT, substitute materials appear to be a viable treatment alternative. So far, there is a lack of data investigating the dimensional changes at implant sites treated with soft-tissue substitutes or FGG.

AIM

The present study aimed at comparing three-dimensional changes of a porcine derived collagen matrix (CM) and FGG for increasing KT at dental implants over a 6-month follow-up period.

MATERIALS AND METHODS

The study enrolled 32 patients exhibiting deficient KT width (i.e., < 2 mm) at the vestibular aspect who underwent soft tissue augmentation using either CM (15 patients/23 implants) or FGG (17 patients/31 implants). The primary outcome was defined as tissue thickness change (mm) at treated implant sites between 1- (S0), 3- (S1), and 6-months (S2). Secondary outcomes considered changes of KT width over a 6-month follow-up period, surgical treatment time, and patient-reported outcomes.

RESULTS

Dimensional analyses from S0 to S1 and from S0 to S2 revealed a mean decrease in tissue thickness of - 0.14 ± 0.27 mm and - 0.04 ± 0.40 mm in the CM group, and - 0.08 ± 0.29 mm and - 0.13 ± 0.23 mm in the FGG group, with no significant differences noted between the groups (3 months: p = 0.542, 6 months: p = 0.659). Likewise, a comparable tissue thickness decrease was observed from S1 to S2 in both groups (CM: - 0.03 ± 0.22 mm, FGG: - 0.06 ± 0.14 mm; p = 0.467). The FGG group exhibited a significantly greater KT gain after 1, 3 and 6 months compared to the CM group (1 month: CM: 3.66 ± 1.67 mm, FGG: 5.90 ± 1.58 mm; p = 0.002; 3 months: CM: 2.22 ± 1.44; FGG: 4.91 ± 1.55; p = 0.0457; 6 months: CM: 1.45 ± 1.13 mm, FGG: 4.52 ± 1.40 mm; p < 0.1). Surgery time (CM: 23.33 ± 7.04 min.; FGG: 39.25 ± 10.64 min.; p = 0.001) and postoperative intake of analgesics were significantly lower in the CM group (CM: 1.2 ± 1.08 tablets; FGG: 5.64 ± 6.39 tablets; p = 0.001).

CONCLUSIONS

CM and FGG were associated with comparable three-dimensional thickness changes between 1 and 6 months. While a wider KT band could be established with FGG, the use of CM significantly reduced surgical time and patients´ intake of analgesics.

The efficacy of a porcine collagen matrix in keratinized mucosa width augmentation: a 10-year follow-up clinical prospective study

PURPOSE

The aim of the present study was to evaluate the long-term effectiveness of a xenogeneic collagen matrix (CM) in pre-prosthetic augmentation of the keratinized mucosa width (KMW) at implant sites.

METHODS

All of the patients with localized implant-supported rehabilitation previously treated with vestibuloplasty and KMW augmentation with a non-cross-linked porcine CM were recalled. KMW was measured clinically in an apico-coronal direction from the mucogingival junction to the mucosal margin at the prosthetic zenith of each crown. Measurements were performed clinically by means of a PCP-UNC15 periodontal probe and rounded to the nearest mm. KMW values recorded at 1 year, 5 and 10 years from the soft tissue augmentation procedure were compared using a one-way repeated-measures ANOVA with Bonferroni multiple comparison post-hoc analysis. The level of significance was set at 0.05.

RESULTS

Measurements were conducted on 13 patients. All implants were in function with no signs of biological complications. All except one implant site showed KMW ≥ 2 mm. KMW decreased significantly from 1 year (3.33 ± 1.11 mm) to 5 years (2.77 ± 0.92 mm) (p = 0.001), and finally remained stable from 5 to 10 years (3.2 ± 0.99 mm) (p = 0.607). From a visual aspect, peri-implant soft tissues were characterized by a good texture and color blending compared to the adjacent teeth, highlighting good integration of the remodeled tissues and stability of the esthetic result.

CONCLUSIONS

The use of a CM in pre-prosthetic soft tissue augmentation at implant sites has proven to be effective in obtaining and maintaining at least 2 mm of KMW around dental implants over a follow-up of 10 years.

A Minimally Invasive Approach to Managing Isolated Gingival Recession

Gingival recession (GR), the apical shift of the gingival margin, results in root surface exposure. Its etiology is multifactorial, including teeth position within the dental arch, bony dehiscence, alveolar mucosa thickness, incorrect toothbrushing, orthodontic treatment, and periodontal disease. Coronally advanced flap (CAF) with a subepithelial connective tissue graft (SCTG) is the gold standard for managing GR. With the introduction of minimally invasive surgery, various techniques proposed for managing GR minimize patient morbidity and maximize surgical outcomes. The present case report is that of a 26-year-old male patient with the primary complaint of sensitivity in the upper right and left back teeth regions. Emdogain was used with SCTG for managing recession on the left side and with the xenogeneic collagen matrix (Mucograft) to cover recession on the right side. Post-operative healing was uneventful, with significant recession reduction and an increase in the width of the attached gingiva at both sites. GR, apart from posing as an esthetic complication, also results in tooth sensitivity. This makes the management of GR very important for which multiple treatment modalities are available. The current case report highlights the success of the minimally invasive tunneling technique in managing isolated GR.

Soft tissue phenotype modification impacts on peri-implant stability: a comparative cohort study

OBJECTIVES

Soft tissue phenotype modification (STPM) could be performed to maintain peri-implant health. Therefore, the aim of the study was to analyze tissue alteration around implants following soft tissue phenotype modification during implant uncovering surgery.

MATERIALS AND METHODS

Patients who had STPM (either pouch roll or modified roll technique) during implant second-stage surgery with at least 12-month follow-up were included. Clinical and radiographic parameters including mucosal tissue thickness (MTT), recession (REC), keratinized mucosa width (KMW), probing pocket depth (PPD), marginal bone loss (MBL), emergence profile, and emergence angle were extracted from 2-week, 2-month, and 12-month visits after second-stage surgery.

RESULTS

Twenty-eight patients with 33 implants that fulfilled the inclusion criteria were included. After soft tissue phenotype modification, at 2 weeks, REC was negatively correlated to mean MTT at mid-buccal site (r =  - 0.41, p = 0.018) and borderline correlated at mid-lingual site (r =  - 0.343, p = 0.051). Stable KMW was maintained from 2 weeks to 12 months with minimal shrinkage rate (3 ~ 14%). MBL change was limited (0.24 ~ 0.47 mm) after STPM. All implants had shallow PPD (≤ 3 mm) with the absence of bleeding on probing. Emergence angle at the mesial side, however, was significantly correlated to surgical techniques, which indicated pouch roll technique would have 6.96 degrees more than modified roll technique (p = 0.024).

CONCLUSIONS

Soft tissue phenotype modification, either pouch roll or modified roll technique, during uncovering surgery resulted in favorable clinical outcomes. Thin mucosal tissue thickness and pouch roll technique are the factors related to more recession at 2 weeks. Pouch roll technique could influence the restorative design by having a wide emergence angle at the mesial side.

CLINICAL RELEVANCE

Modified and pouch roll techniques during uncovering surgery were viable methods to yield favorable peri-implant health, while the preciseness of pouch roll technique was required to avoid mucosal recession and inadequate restorative design.

Soft tissue augmentation with a volume-stable collagen matrix or an autogenous connective tissue graft at implant sites: Five-year results of a randomized controlled trial post implant loading

BACKGROUND

Interventions to augment the mucosal thickness around dental implants are indicated to optimize esthetics and maintain peri-implant health. However, there is a lack of clinical data on the long-term performance of soft tissue substitutes, such as volume-stable collagen matrix (VCMX), compared to autogenous grafts, such as subepithelial connective tissue grafts (SCTGs). This randomized controlled trial aimed to assess 5-year data on clinical and radiographic outcomes at implant sites previously augmented with VCMX or SCTG.

METHODS

Twenty patients were randomly assigned for soft tissue augmentation with VCMX or SCTG at single implant sites. Following abutment connection, final restorations were inserted (baseline; BL) and patients were reexamined up to 5 years (FU-5). Measurements included clinical data, marginal bone levels, mucosal thickness, and ridge contour changes. Nonparametric tests and estimates were applied for the statistical analysis.

RESULTS

The median buccal mucosal thickness increased by 0.3 mm (Q1: -0.8; Q3: 1.0) in the VCMX group (P = 0.656) and 0.3 mm (Q1: 0.0; Q3: 1.0) in the SCTG group (P = 0.188) between BL and FU-5 (intergroup P = 0.752), while the ridge contour decreased by a median of -0.3 mm (-0.9; -0.1) (P = 0.078) for VCMX and -0.3 mm (-0.4; -0.2) (P = 0.039) for SCTG (intergroup P = 0.817). Peri-implant health was maintained in both groups with stable clinical and radiographic outcomes and without significant differences between the treatments.

CONCLUSION

Despite the limited power and considerable dropout rate in the present study, soft tissue augmentation at implant sites with either VCMX or SCTG resulted in similar stable peri-implant tissues, favorable esthetics, and clinically negligible contour changes at 5 years post loading.

Soft-Tissue Augmentation around Dental Implants with a Connective Tissue Graft (CTG) and Xenogeneic Collagen Matrix (CMX)-5-Year Follow-Up

Proper horizontal and vertical thickness of the gingival connective tissue has been proven to be one of the success criteria in dental implant and reconstructive surgery. When thin tissue is found, gingiva augmentation methods can be used to increase the quality and volume of the tissue. Many methods have been described, among them pedicle soft-tissue flaps or autogenic tissue grafts. As an alternative to patients' own tissue, xenogenic materials can be used for grafting. The fundamental issue is to choose a material that will ensure the maximum therapeutic effect, while also minimizing the negative influence on the patient's health. The aim of this study was to compare gingival augmentation procedures using a palatal connective tissue graft (CTG) and an xenogenic soft-tissue substitute, Geistlich Mucograft (xenogeneic collagen matrix; CMX), and assess whether the timing of the graft surgery influences the clinical outcomes. The original study was a randomized control trial with a total of 75 implants placed. The patients received the soft-tissue thickening 3 months before the implant placement or 3 months after the implant placement (depending on the group). A connective tissue graft (CTG) or Geistlich Mucograft were used (depending on the group). For both the CTG and Geistlich Mucograft, better clinical outcomes were observed for maintaining the alveolar bone level and the thickness of the attached gingiva compared to the control group with no gingival augmentation. The Geistlich Mucograft showed good clinical performance in comparison to the control. Soft-tissue augmentation with the CTG before the implant placement was found to be most efficient method in terms of a stable increase of the tissue thickness since, throughout the entire observation period, the greatest increase of 1.035 mm (SD = 0.73 mm) in thickness was observed. Statistically important differences in the tissue thickness baseline compared after 5 years were observed for groups G1 vs. G2b (no augmentation vs. CTG before), G1 vs. G3b (no augmentation vs. CTG after) and for groups G2b vs. G3a (CTG before vs. CMX after).

Xenogeneic collagen matrix versus free gingival graft for augmenting keratinized mucosa around posterior mandibular implants: a randomized clinical trial

OBJECTIVES

To assess the clinical efficacy of xenogeneic collagen matrix (XCM) plus apically positioned flap (APF) in augmenting the keratinized mucosa (KM) width (KMW) and thickness (KMT) around posterior mandibular implants and compare it with free gingival graft (FGG) plus APF.

MATERIAL AND METHODS

Thirty patients with KMW ≤ 2 mm in the posterior mandibular implant site were randomly allocated to the FGG group (FGG plus APF) or the XCM group (XCM plus APF). Clinical assessments, including KMW and KMT, shrinkage rate of established KM, and peri-implant soft tissue health, were evaluated during a 6-month follow-up. Additionally, the esthetic outcomes and patient-reported postoperative morbidity were investigated.

RESULTS

At 6 months, the KMW measured 3.60 ± 0.79 mm in the FGG group and 3.28 ± 0.96 mm in the XCM group (p = 0.186). Both groups showed a tendency for graft contraction (FGG, 42.11%; XCM, 53.22%). The KMT measured 1.24 ± 0.34 mm in the FGG group and 0.95 ± 0.29 mm in the XCM group, with statistical difference (p = 0.002). No difference in the peri-implant soft tissue health was observed between the two groups (p > 0.05), but the esthetic outcomes were better in the XCM group (p < 0.05).

CONCLUSIONS

XCM plus APF rendered a similar clinical efficacy in augmenting KMW as that with FGG plus APF, but with higher shrinkage. XCM plus APF was inferior with respect to FGG plus APF in augmenting KMT. The esthetic outcomes were better with XCM plus APF than FGG plus APF. Clinical relevance XCM plus APF graft was inferior with respect to FGG plus APF in augmenting KMT.

TRIAL REGISTRATION

Trial registration number: ChiCTR2200058027 and date: 03/27/2022.

First-in-Human Study to Investigate the Safety Assessment of Peri-Implant Soft Tissue Regeneration with Micronized-Gingival Connective Tissue: A Pilot Case Series Study

Background: We have recently proposed an alternative strategy of free gingival graft (FGG) and connective tissue graft (CTG) using micronized-gingival connective tissues (MGCTs). The advantage of this strategy is that MGCTs from a small piece of maxillary tuberosity can regenerate the keratinized tissue band. However, safety and efficacy have not yet been established in patients. This clinical study was a pilot case series, and the objective was to assess the safety and the preliminary efficacy of MGCTs on peri-implant mucosa regeneration. Methods: This was a pilot interventional, single-center, first-in-human (FIH), open (no masking), uncontrolled, and single-assignment study. A total of 4 patients who needed peri-implant soft tissues reconstruction around dental implants received transplantation of atelocollagen-matrix with MGCTs micronized by the tissue disruptor technique. The duration of intervention was 4 weeks after surgery. Results: This first clinical study demonstrated that using MGCTs did not cause any irreversible adverse events, and it showed the preliminary efficacy for peri-implant soft tissues reconstruction in dental implant therapy. Conclusions: Though further studies are needed on an appropriate scale, as an alternative strategy of FGG or CTG, MGCTs might be promising for peri-implant mucosa reconstruction without requiring a high level of skills and morbidity to harvest graft tissues.

Tissue integration and biodegradation of soft tissue substitutes with and without compression: an experimental study in the rat

OBJECTIVES

To analyze the influence of compression on tissue integration and degradation of soft tissue substitutes.

MATERIAL AND METHODS

Six subcutaneous pouches in twenty-eight rats were prepared and boxes made of Al₂O₃ were implanted and used as carriers for soft tissue substitutes: a collagen matrix (MG), two volume-stable collagen matrices (FG/MGA), and a polycaprolactone scaffold(E). The volume-stable materials (FG/MGA/E) were further implanted with a twofold (2) and a fourfold (4) compression, created by the stacking of additional layers of the substitute materials. The samples were retrieved at 1, 2, and 12 weeks (10 groups, 3 time points, n = 5 per time point and group, overall, 150 samples). The area fraction of infiltrated fibroblasts and inflammatory cells was evaluated histologically. Due to within-subject comparisons, mixed models were conducted for the primary outcome. The level of significance was set at 5%.

RESULTS

The area fraction of fibroblasts increased in all groups over time. At 12 weeks, the densely compressed materials FG4 (1.1%), MGA4 (1.7%), and MGA2 (2.5%) obtained lower values as compared to the other groups, ranging between 4.7 (E2) and 6.5% (MG). Statistically significant differences (p ≤ 0.05) were observed between groups FG4 vs MG/FG2/E/E4 as well as between MGA4 vs MG/FG2/E/E4 and E vs MGA2.

CONCLUSIONS

Higher levels of compression led to delayed tissue integration. The effect of different compression levels was more distinct when compared to the differences between the materials.

CLINICAL RELEVANCE

All biomaterials demonstrated tissue integration and a minimal concomitant inflammatory reaction. Clinically, it might be more favorable to obtain a sufficient flap release or to reduce the material size to improve the tissue integration processes.

The Use of Collagen Matrix in the Treatment of Gingival Recession—A Pilot Study

Background. Gingival recessions are common mucogingival deformities and conditions around teeth, which are described as the apical migration of tissues in the relation to the cementoenamel junction. One of the types of graft materials used to treat these recessions is the collagen graft material. The aim of this pilot study was to evaluate the effectiveness of the use of the collagen matrix combined with the coronally advanced flap surgery method to cover dental recessions, after a 12 month follow-up period. Methods. The following parameters were assessed in 20 patients, with 38 single or multiple Miller class I or II gingival recessions: depth of the recession—RD; width of the recession—RW; height of the keratinized tissue—HKT; and thickness of the keratinized gingivae—GT. The percentage of the root coverage after 12 months was also calculated. Results. There was a significant difference in the RD and RW values before and after the procedure. On average, the RD decreased by 3.39 mm, and the RW by 3.87 mm. Moreover, the values of the GT and HKT, before and after the treatment, significantly increased by 0.98 mm and 1.13 mm, respectively. The partial root coverage was 43.48%, and the total root coverage was 56.52%. Conclusion. The use of the collagen matrix with a split thickness gingival flap to cover the gingival recessions is a predictable and effective method when the clinician carefully follows the recommendation of the producer, which was confirmed in a 1 year follow-up with good clinical results.

Investigation of the palatal soft tissue volume: a 3D virtual analysis for digital workflows and presurgical planning

Background

In mucogingival and implant surgery, an autologous soft tissue graft from the palate is the gold standard for reconstructing missing keratinised soft tissue and volume. Previously, presurgical measurements of the graft harvesting site were described with two-dimensional (2D) linear measurements. The present observational clinical study aimed to evaluate a three-dimensional (3D) measurement method for determining the present palatal soft tissue volume for each patient individually.

Methods

Pre-existing cone beam computed tomography (CBCT) scans of 20 patients were converted into 3D Standard Tessellation Language models of the bone surface. Intraoral impressions of the maxilla were taken and digitised to visualise the gingival surface. The resulting virtual models of bone (reference value) and gingival (actual value) surfaces were merged, with tooth surfaces used for registration. The region between the central incisors and the hard palate was subdivided into 5 regions of interest (ROIs). The distance between palatal bone and gingival surface was analysed both volumetrically and linearly, and the results were statistically evaluated for the ROIs.

Results

The average gingival surface area on the palate was 19.1 cm², and the mean volume was 58.2 cm³ (± 16.89). Among the ROIs, the mean linear value was highest in the most distal region, from the second molar to the hard palate (4.0 ± 1.09 mm) and lowest in the canine region (1.9 ± 0.63 mm). For mean distance, significant differences were found for the anterior palate and the most posterior palate in comparison with all other ROIs (p < 0.01). The volume measurements also declined significantly and steadily between the posterior (1.9 ± 1.0 cm³) and anterior palates (0.4 ± 0.2 cm³).

Conclusions

By merging digital data, palatal soft tissue could be quantified virtually. The results were reliable and comparable to previous findings with linear measurement methods. This 3D soft tissue volume analysis method fully exploited the diagnostic potential of data that are frequently collected for presurgical planning in oral surgery (i.e., CBCT + surface scans). This evaluation method might be useful for volumetric and linear measurements in other applications in anatomy and for determining palatal soft tissue dimensions in the planning stage before surgical interventions.

Trial registration

This observational clinical trial was retrospectively registered in the German Clinical Trials Register, reference number: DRKS00023918.

Full-Thickness Oral Mucoperiosteal Defects: Challenges and Opportunities

Regenerative engineering strategies for the oral mucoperiosteum, as may be needed following surgeries, such as cleft palate repair and tumor resection, are underdeveloped compared with those for maxillofacial bone. However, critical-size tissue defects left to heal by secondary intention can lead to complications, such as infection, fistula formation, scarring, and midface hypoplasia. This review describes current clinical practice for replacing mucoperiosteal tissue, including autografts and allografts. Potentially paradigm-shifting experimental regenerative engineering strategies for mucoperiosteal wound healing, such as hybrid grafts and engineered matrices, are also discussed. Throughout the review, the advantages and disadvantages of each replacement or regeneration strategy are outlined in the context of clinical outcomes, quality of life for the patient, availability of materials, and cost of care. Finally, future directions for research and development in the area of mucoperiosteum repair are proposed, with an emphasis on identifying globally available and affordable solutions for promoting mucoperiosteal regeneration. Impact statement Unassisted oral mucoperiosteal wound healing can lead to severe complications such as infection, fistulae, scarring, and developmental abnormalities. Thus, strategies for promoting wound healing must be considered when mucoperiosteal defects are incident to oral surgery, as in palatoplasty or tumor resection. Emerging mucoperiosteal tissue engineering strategies, described in this study, have the potential to overcome the limitations of current standard-of-care donor tissue grafts. For example, the use of engineered mucoperiosteal biomaterials could circumvent concerns about tissue availability and immunogenicity. Moreover, employment of tissue engineering strategies may improve the equity of oral wound care by increasing global affordability and accessibility of materials.

Efficacy of soft tissue substitutes, in comparison with autogenous grafts, in surgical procedures aiming to increase the peri-implant keratinized mucosa: A systematic review

OBJECTIVES

The aim of this systematic review was to evaluate the efficacy of soft tissue substitutes compared to autogenous gingival grafts in surgical procedures aimed at increasing the width of keratinized mucosa (KM) around dental implants.

MATERIALS AND METHODS

Two focused questions were developed: PICOS #1) "What is the efficacy of surgical procedures using soft tissue substitutes, as compared to autogenous grafts, to increase the amount of peri-implant keratinized mucosa, in randomized clinical trials (RCTs) and controlled clinical trials (CCTs)?"; and PICOS #2) "What is the effectiveness of soft tissue substitutes to increase the amount of peri-implant keratinized mucosa, in RCTs, CCTs, cohort studies or case series?". Besides KM augmentation, other relevant outcomes such as clinical and radiographic peri-implant outcomes, incidence of biological complications, surgical time, or patient-reported outcome measures (PROMs) were collected. Meta-analyses were performed whenever possible.

RESULTS

Ten publications and an unpublished study were included. KM augmentation was significantly greater for autogenous grafts (n = 6; weighted mean difference (WMD) = -0.9 mm; 95% confidence interval (CI) [-1.4; -0.3]; p = .001). However, no significant differences between autogenous grafts and soft tissue substitutes were observed when exclusively xenografts were considered (n = 5; WMD=-0.8 mm; 95% CI [-1.6; 0.0]; p = .062). Surgical time and postsurgical pain seemed to be reduced by the use of soft tissue substitutes.

CONCLUSIONS

Free gingival grafts (FGG) are more effective in the augmentation of KM mucosa around dental implants than soft tissue substitutes. However, substitutes of xenogeneic origin may be an alternative to autogenous tissues.

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.

Fibrin immobilization vestibular extension (FIVE): A case series

AIMS

The objective of the present case series is to report on the rationale, surgical technique and outcome of a protocol for peri-implant mucosal phenotype modification therapy, referred to as "fibrin immobilization vestibular extension (FIVE)".

MATERIAL AND METHODS

The protocol utilized entailed apical positioning and stabilization of peri-implant flap with modular screws. The screws were also used for the immobilization of solid matrix platelet-rich fibrin to fill the gap created between apically positioned flap and the crestal margin of the flap.

RESULTS

A total of 30 patients (12 male, 18 females) with 93 implants were treated with FIVE protocol for various indications, including for vestibular extension following alveolar ridge augmentation (N = 6), preprosthetic (N = 9), postprosthetic (N = 2), and peri-implantitis (N = 13). The keratinized mucosal width preoperatively was 1.67 mm with 95% confidence interval [CI] (1.46, 1.88). Immediately following FIVE surgery, the vestibule was extended to 9.10 with 95% CI (8.44, 9.76). At 3 months, 4.9 mm (95% CI: 4.5-5.2 mm) of peri-implant keratinized mucosal width was present. The keratinized mucosal width remained relatively stable thereafter and was 4.0 mm (95% CI: 3.5-4.5 mm) at 3 years post-FIVE surgery. When overall group means across all time points were analyzed, maxilla had mean of 6.1 mm (95% CI: 5.8-6.5) versus mandible exhibited mean of 5.1 mm (95% CI: 4.6-5.6 mm). The mean of maxilla was significantly higher than that of the mandible (p < 0.0001) across all time points. Treatment of peri-implantitis with FIVE lead to significant pocket reduction and wide band of keratinized mucosa. Seven of 38 implants in 3 of 13 peri-implantitis patients were removed due to advanced peri-implantitis.

DISCUSSION

The present case series provides proof-of-principle data for efficacy of FIVE for peri-implant phenotype modification therapy that generated attached keratinized mucosa in a variety of applications. This protocol provides an alternative to procedures involving harvesting of autogenous mucosal graft.

Retrospective analysis of keratinized tissue augmentation using a xenogeneic collagen matrix for resolving peri-implant mucositis and peri-implantitis

PURPOSE

The significance of keratinized tissue for peri-implant health has been emphasized. However, there is an absence of clinical evidence for the use of a xenogeneic collagen matrix (XCM) to manage peri-implant mucositis and peri-implantitis. Therefore, the purpose of this study was to investigate outcomes after keratinized tissue augmentation using an XCM for the management of peri-implant diseases.

METHODS

Twelve implants (5 with peri-implant mucositis and 7 with peri-implantitis) in 10 patients were included in this study. Non-surgical treatments were first performed, but inflammation persisted in all implant sites. The implant sites all showed a lack of keratinized mucosa (KM) and vestibular depth (VD). Apically positioned flaps with XCM application were performed. Bone augmentation was simultaneously performed on peri-implantitis sites with an intrabony defect (>3 mm). The following clinical parameters were measured: the probing pocket depth (PPD), modified sulcular bleeding index (mSBI), suppuration (SUP), keratinized mucosal height (KMH), and VD.

RESULTS

There were no adverse healing events during the follow-up visits (18±4.6 months). The final KMHs and VDs were 4.34±0.86 mm and 8.0±4.05 mm, respectively, for the sites with peri-implant mucositis and 3.29±0.86 mm and 6.5±1.91 mm, respectively, for the sites with peri-implantitis. Additionally, the PPD and mSBI significantly decreased, and none of the implants presented with SUP.

CONCLUSIONS

Keratinized tissue augmentation using an XCM for sites with peri-implant mucositis and peri-implantitis was effective for increasing the KMH and VD and decreasing peri-implant inflammation.

Dimensional Changes in Free Epithelialized Gingival/Mucosal Grafts at Tooth and Implant Sites: A Prospective Cohort Study

BACKGROUND

A study was made of the dimensional changes in free epithelialized gingival/mucosal grafts (FEGs) used to augment keratinized tissue (KT) at tooth and implant sites, and of the confounders influencing the dynamic changes over 6 months of follow-up.

MATERIAL AND METHODS

A prospective cohort interventional study was made of implant and tooth sites needing keratinized tissue augmentation by means of an apically positioned flap and FEG. Six intraoperative variables were recorded at baseline (T0). In addition, graft width (GW), graft length (GL) and graft dimension (GD) were assessed at three weeks (T1), three months (T2) and 6 months of follow-up (T3). Univariate and multivariate analyses were performed to explore associations between the demographic and intraoperative variables and the outcomes over the study period.

RESULTS

Based upon an a priori power sample size calculation, a total of 56 consecutive patients were recruited, of which 52 were available for assessment. A total of 73 graft units were included in 122 sites. At T3, the mean change in GD in FEG was 40.21%. In particular, the mean changes in GL and GW were 12.13% and 33.06%, respectively. Statistically significant changes in GD were recorded from T0 to T1 (p<0.0005) and from T1 to T2 (p<0.0005), but not from T2 to T3 (p = 0.13). The change in GD at T3 was 33.26% at tooth and 43.11% at implant site level (p = 0.01). Age and GW assessed at T0 proved to be related to the changes in GD and GW in the univariate and multivariate analyses. The univariate analysis showed the avascular area (AA) to be related to the changes in GD and GW at the implant sites, while graft thickness (GT) was associated to changes in GD and GW at the tooth sites in the univariate and multivariate analyses.

CONCLUSIONS

Free epithelialized grafts are exposed to dimensional changes that result in a reduction of approximately 40% of the original graft dimension - the changes being approximately 10% greater at the implant sites than at the tooth sites (NCT04410614). This article is protected by copyright. All rights reserved.

A retrospective comparison of 3 approaches of vestibuloplasty around mandibular molar implants: apically positioned flap versus free gingival graft versus modified periosteal fenestration

PURPOSE

This study aimed to clinically evaluate the efficacy of vestibuloplasty around lower molar implants using 3 different modalities: apically positioned flap alone (APF), APF with a free gingival graft (FGG), and APF with modified periosteal fenestration (mPF).

METHODS

Three different vestibuloplasty procedures during second-stage implant surgery were performed at the mandibular molar area in 61 patients with a shallow vestibule and insufficient keratinized tissue (KT). The clinical measurements of KT width were recorded at baseline, immediately after surgery (T0), 6 months after surgery (T6), and 12 months after surgery (T12). Soft tissue esthetic scores were measured.

RESULTS

An additional KT width gain from baseline to T12 of approximately 2 mm was obtained with FGG and mPF compared to that with APF. Shrinkage of the re-established tissue was lower with mPF and FGG than with APF, whereas the esthetic profile was better with APF and mPF than with FGG.

CONCLUSIONS

Within the limitations of this study, mPF showed potential as a promising approach for vestibuloplasty around the lower molar implants compared to the traditional APF and FGG.

The Effect of Three Surgical Therapies to Increase Keratinized Mucosa Surrounding Dental Implants with Peri-Implantitis: A Pilot Study

Background and Objectives: The purpose of this pilot study was to evaluate the clinical outcomes of three different methods for increasing the keratinized mucosa (KM) surrounding dental implants with peri-implantitis. Materials and methods: Twenty implant sites with peri-implantitis were divided into: (1) porcine collagen matrix (CM) group: seven implant sites; (2) apically positioned flap (APF) group: eight implant sites; and (3) free gingival graft (FGG) group: five implant sites. The KM width and clinical parameters (probing pocket depth (PPD) and bleeding on probing (BOP)) were measured at time points: before surgery (T0) and 30 (T1), 60 (T2), 90 (T3), and 180 (T4) days after surgery. Results: Regarding KM width, all the groups had significant differences for increasing horizontal and vertical KM width. The CM and FGG groups had greater KM than the APF group. There was a decrease in PPD in all three groups. APF and FGG showed significant differences in PPD at T1 and T2 compared to T0. Only the FGG group showed a significant difference in PPD at T3 and T4 compared with that at T0. BOP values were also reduced in all the groups at T1-T4 compared to T0. The APF and FGG groups showed a significant decrease in BOP. Conclusions: Three surgical therapies presented favorable results for increasing the KM surrounding implants. Compared with the FGG group, the CM showed similar results in increasing the KM around the dental implants with peri-implantitis.

Laterally rotated flap for soft tissue augmentation around maxillary loaded osseointegrated dental implants: preliminary results of a pilot study

A minimal width and thickness of keratinized and attached soft tissue is desirable to prevent peri-implant diseases. This report describes the preliminary results of a pilot study of a surgical approach for soft tissue augmentation around loaded dental implants in the partially or totally edentulous maxilla. Four patients presenting eight maxillary implants with a buccal peri-implant soft tissue deficiency received a laterally rotated flap. A buccal mesial and apical recipient area was created around each implant, and a pediculated keratinized graft was rotated 90° from the distopalatal and positioned and sutured on the peri-implant buccal aspect. All implants treated showed a gain in buccal clinical peri-implant attachment (1.37 ± 0.44 mm) and buccal soft tissue levels (2.06 ± 1.40 mm) and interproximal soft tissue levels (1 ± 0.75 mm). The technique provided quality soft tissue with a gain in soft tissue thickness (3.06 ± 0.68 mm) and keratinized wide tissue (4.69 ± 0.80 mm) with minimal morbidity (1575 ± 549.67 mg of ibuprofen) and maintenance of prosthetic loading. Peri-implant soft tissue stability was maintained for 13.5 ± 1.87 months. Laterally rotated flap can be applied and provide clinical benefits to compromised implants due to the presence of buccal peri-implant soft tissue deficiency. Further studies are required to confirm these preliminary results.

Is there any biomaterial substitute for peri-implant soft tissue phenotype modification? A network meta-analysis of the appraisal literature

Evidence shows that an increased width and thickness of the keratinized mucosa favours peri-implant health. The aim of this network meta-analysis was to compare the clinical effects of alternative biomaterials for peri-implant soft tissue phenotype modification (PSPM) in patients with dental implants when compared to autologous tissue grafts. An electronic search without language or date limitations was performed in four databases and the grey literature for articles published until November 2020. The eligibility criteria included randomized clinical trials (RCTs) evaluating the clinical outcomes of biomaterials for PSPM. A pairwise and network meta-analysis was conducted for each parameter to assess and compare the outcomes between the different treatment arms for the primary and secondary outcomes. A total of 11 RCTs were included in this review. The free gingival graft (FGG) showed the best clinical effect for increasing keratinized mucosa width (KMW). When compared in a network, the FGG demonstrated the best treatment ranking of probability results, followed by connective tissue graft (CTG), acellular dermal matrix (ADM), and xenogeneic collagen matrix (XCM). For the parameters 'mucosa thickness' and 'participant satisfaction with aesthetics', the results were CTG > ADM > XCM and XCM > ADM > CTG, respectively. Autogenous tissue grafts (FGG/CTG) demonstrate the best results in increasing KMW and mucosa thickness when compared to the other biomaterials.

Patient-reported outcome measures and clinical outcomes following peri-implant vestibuloplasty with a free gingival graft versus xenogeneic collagen matrix: a comparative prospective clinical study

BACKGROUND

The objective of this study was to compare patient-reported outcome measures (PROMs) and clinical outcomes after augmentation with xenogeneic collagen matrix (XCM) or free gingival graft (FGG) during different postoperative phases.

METHODS

Forty-two patients (21 per group) with keratinized mucosa width (KMW) of < 2 mm at buccal implant sites in the posterior mandible were enrolled. All underwent vestibuloplasty and were allocated to either FGG (control) or XCM (test) group. Intraoperative morbidity of pain, stress, nausea, tolerance to time, and acceptance of surgery were evaluated immediately after surgery. The severity and duration of subjective pain, swelling, and bleeding were compared within a 2-week postoperative period. The willingness to retreat and satisfaction were assessed at 6 months. All PROMs were obtained using questionnaires and visual analog scales. The buccal KMW and other peri-implant parameters were also evaluated.

RESULTS

No significant between-group differences were observed in PROMs immediately after surgery, except acceptance of surgery (0, 0-30.0 vs. 30, 0-50.0, p = 0.025). At 2 weeks, pain severity (46.7 ± 25.9 vs 61.9 ± 20.2, p = 0.040) and duration (5.52 ± 3.57 vs 8.48 ± 2.80, p = 0.005) were significantly lower in the test group, and pain perception during speaking and chewing was significantly higher for FGG, with no significant between-group differences in swelling and bleeding. At 6 months, the test group showed a higher willingness to retreat (76% vs 43%, p = 0.021); however, satisfaction with treatment outcomes was similar in both groups. At 6 months, the gain of KMW was significantly higher in FGG than in XCM (XCM: 1.57 ± 1.69 mm, FGG: 2.68 ± 1.80 mm, p = 0.003). Other peri-implant parameters did not show significant differences.

CONCLUSIONS

Within the limitation of the present nonrandomized study, XCM demonstrated more positive PROMs than FGG during different postoperative phases, mainly for less pain perception during the early healing stage, but was inferior to FGG in terms of gain of KMW. For KMW augmentation in the posterior mandible, XCM may be indicated when patients can bear little pain.

CLINICAL TRIAL REGISTRATION

ChiCTR1900022575 , date of registration: 17/4/2019, retrospectively registered.

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.

Clinical evaluation of xenogeneic collagen matrix versus free gingival grafts for keratinized mucosa augmentation around dental implants: A randomized controlled clinical trial

AIM

To evaluate the outcomes of an apically repositioned flap (ARF) plus xenogeneic collagen matrix (XCM) in augmenting keratinized mucosa width (KMW) around dental implants when compared with ARF plus free gingival grafts (FGG).

MATERIALS AND METHODS

Twenty-six participants with at least one site with KMW ≤2 mm were randomized into FGG or XCM group. Clinical examinations were performed at baseline and at 2 and 6 months after surgery, including KMW, keratinized mucosa thickness, gingival index (GI), and probing depth (PD). Post-operative pain and patient satisfaction were also evaluated.

RESULTS

At 6 months, FGG attained a greater increase of KMW and thicker mucosa than XCM (4.1 ± 1.6 mm vs. 1.8 ± 1.0 mm, p < .001; 1.7 ± 0.6 mm vs. 1.2 ± 0.3 mm, p < .01). Regarding GI, PD, post-operative pain, aesthetic outcomes, and patient satisfaction, no significant difference could be detected. Moreover, the operation time of XCM group was shorter (60 ± 9 min vs. 39 ± 8 min, p < .001).

CONCLUSIONS

FGG could result in greater increase of KMW than XCM, though both could increase KMW, maintain peri-implant health, and attain comparable aesthetic outcomes. The use of XCM was associated with reduced operation time.

Biocompatibility Evaluation of Human and Porcine Acellular Dermal Matrix on Human Primary Gingival Fibroblasts: In Vitro Comparative Study

Objective  Allogeneic and xenogeneic acellular dermal matrix (ADM) grafts have been used to treat periodontal soft tissue defects. The purpose of the current study was to compare the effect of human ADM (AlloDerm) and porcine ADM (Derma) on human primary gingival fibroblasts in vitro regarding the biocompatibility test.

Materials and Methods  Gingival fibroblasts were obtained from healthy adult gingiva and seeded on AlloDerm or Derma ADM in 96-well plate. The control cells were grown on a surface-treated polystyrene cell-culture plate without matrix. The cells were cultured for 3, 7, and 14 days. The fibroblasts morphology was examined using inverted microscopy, and the cell viability of fibroblasts adherent to the dermal matrix was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay after 3, 7, and 14 days in culture. The data were statistically evaluated by one-way analysis of variance. p -Value of 0.05 was considered significant.

Results  Gingival fibroblasts adjacent to the AlloDerm and Derma matrices were healthy, attached to the well, and did not exhibit any cytopathic changes similar to control. There were no statistically significant differences in the cell viability between the gingival fibroblasts attached to Derma and AlloDerm on day 3 ( p = 0.841), day 7 ( p = 0.198), and day 14 ( p = 0.788).

Conclusion  Considering this in vitro study’s limitations, both human and porcine ADM were compatible with the surrounding human primary gingival fibroblasts. No significant differences were observed in the cell viability between the gingival fibroblasts that were attached to Derma and AlloDerm.

Engaging a polylactide copolymer in oral tissue regeneration: first validation of Suprathel® for guided epithelial and osseous healing

The present study investigated the capacity of Suprathel^® (a copolymer membrane, so far validated for skin regeneration) to also regenerate oral tissue – mucosa and bone, by comparing this biomaterial, in a split-mouth rabbit model, to Mucoderm^®, a xenogeneic collagen matrix certified for keratinized oral mucosa healing. The clinical reason behind this experimental animal model was to determine whether the benefits of this advanced skin regeneration product (Suprathel^®) could be conveyed for future evaluation in clinical trials of oral tissue regeneration in humans. The outcomes of this study validated the use of Suprathel^®, a terpolymer of polylactide with trimethylene carbonate and ε-caprolactone, for stimulation of oral epithelium and alveolar bone regeneration in rabbits. Both Suprathel^® and Mucoderm^® exhibited comparable results and the null hypothesis stating a comparable regenerating effect of these two materials could not be rejected.

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.

Second-stage surgery in the posterior maxilla to enhance and thicken the keratinized gingiva - a case report

PURPOSE

Bone augmentation and implant placement often lead to a coronal shift of the soft tissue. Therefore replacement of the mucogingival border during second-stage surgery is required. Different techniques have been described in the literature.

MATERIAL AND METHODS

In this case report a new technique for second-stage surgery from a combination of a modified roll flap, an apically repositioned split thickness flap and thick free gingival grafts between the implants will be described for predictable gain of keratinized mucosa around and between dental implants.

RESULTS

Stable soft tissue conditions between the implants and buccal in the posterior maxilla could be gained showing almost no post-surgical resorption.

CONCLUSION

With this modified technique for second-stage surgery functional and esthetic results can be achieved.

A Novel Volume-Stable Collagen Matrix Induces Changes in the Behavior of Primary Human Oral Fibroblasts, Periodontal Ligament, and Endothelial Cells

The aim of the present study was to investigate the influence of a novel volume-stable collagen matrix (vCM) on early wound healing events including cellular migration and adhesion, protein adsorption and release, and the dynamics of the hemostatic system. For this purpose, we utilized transwell migration and crystal violet adhesion assays, ELISAs for quantification of adsorbed and released from the matrix growth factors, and qRT-PCR for quantification of gene expression in cells grown on the matrix. Our results demonstrated that primary human oral fibroblasts, periodontal ligament, and endothelial cells exhibited increased migration toward vCM compared to control cells that migrated in the absence of the matrix. Cellular adhesive properties on vCM were significantly increased compared to controls. Growth factors TGF-β1, PDGF-BB, FGF-2, and GDF-5 were adsorbed on vCM with great efficiency and continuously delivered in the medium after an initial burst release within hours. We observed statistically significant upregulation of genes encoding the antifibrinolytic thrombomodulin, plasminogen activator inhibitor type 1, thrombospondin 1, and thromboplastin, as well as strong downregulation of genes encoding the profibrinolytic tissue plasminogen activator, urokinase-type plasminogen activator, its receptor, and the matrix metalloproteinase 14 in cells grown on vCM. As a general trend, the stimulatory effect of the vCM on the expression of antifibrinolytic genes was synergistically enhanced by TGF-β1, PDGF-BB, or FGF-2, whereas the strong inhibitory effect of the vCM on the expression of profibrinolytic genes was reversed by PDGF-BB, FGF-2, or GDF-5. Taken together, our data strongly support the effect of the novel vCM on fibrin clot stabilization and coagulation/fibrinolysis equilibrium, thus facilitating progression to the next stages of the soft tissue healing process.

Clinical evaluations of free gingival grafting before implant placement to increase keratinized tissue width in molar regions: A retrospective case series

OBJECTIVES

To evaluate the dimensional changes of the keratinized tissue width (KTW) in molar regions after augmentation by free gingival grafts (FGG) before implant placement.

MATERIAL AND METHODS

In seventeen patients, twenty implant sites in molar regions with KTW ≤3 mm at the buccal aspect received FGG 2 months before implant placement. KTW at the buccal aspect was measured before FGG (T0), immediately before implant placement (T1), at the time of impression taking for final prosthesis fabrication (T2), and at the end of the follow-up period after loading (T3, 12-48 months). Changes in KTW before and after FGG, as well as the alterations during the follow-up period after loading, were analyzed. Shapiro-Wilk test, paired Student's t test, and Wilcoxon signed-rank test were used for the data analysis at α = 0.05.

RESULTS

KTW at the buccal aspect of the alveolar ridge was observed with a significant gain of 5.9 ± 1.3 mm at T1 (p < .001). The shrinkage of KTW from T2 to T3 was 8.5%, which was limited but statistically significant (p = .008). KTW at the buccal aspect of implant restorations was 5.0 ± 1.5 mm at T3.

CONCLUSIONS

Within the limitations of the present study, our data suggest that using FGG to increase KTW in molar regions before implant placement had a predictable result. The buccal KTW had a limited reduction and was ≥3 mm with more than 12 months of follow-up after loading.

Randomized, controlled, clinical trial to evaluate a xenogeneic collagen matrix as an alternative to free gingival grafting for oral soft tissue augmentation: A 6- to 8-year follow-up

BACKGROUND

The purpose of this follow up study was to determine if a xenogeneic collagen matrix (CMX) is as effective as free gingival graft (FGG) in preventing further recession 6+ years following vestibuloplasty.

METHODS

This study was a single-blind (examiner), randomized, controlled, split-mouth study of 30 subjects with insufficient zones of KT (< 2 mm), associated with at least two, paired teeth. The study utilized a within subject treatment comparison to examine non-inferiority according to primary and secondary endpoints 6+ years after therapy. The original study primary efficacy endpoint was keratinized tissue width (KTw); however, in this report, prevention of recession (Rec) was also examined, along with traditional, secondary clinical measures, histopathology of mucosal biopsies and exploratory, patient reported outcomes (PROs) for pain and satisfaction.

RESULTS

A total of 23 of the 30 original, study patients were available for 6 to 8-year postoperative assessment, and these patients were representative of the original patient population. For preventing further Rec, CMX was not inferior to FGG (ΔRec = -0.07 ± 1.26 mm for CMX and -0.17 ± 0.78 mm for FGG, P = 0.710). There were no adverse results observed, and histological assessment indicated normal, keratinized gingiva for both therapies. Tissue texture and color match to surrounding, native tissues were significantly better for CMX, and patients preferred CMX over FGG therapy.

CONCLUSIONS

CMX appears to be a suitable substitute for FGG 6+ years after therapy.

Keratinized tissue gain after free gingival graft augmentation procedures around teeth and dental implants: A prospective observational study

AIM

The primary goal was to compare the amount of keratinized tissue width (KTW) gain after free gingival graft (FGG) procedures around implants and teeth after 6 and 12 months of healing.

MATERIALS AND METHODS

Patients with mucogingival defects (<2 mm of KT) around teeth and implants underwent a gingival augmentation procedure by means of a FGG. Clinical measurements were performed with an individual stent to determine keratinized tissue width (KTW), length (KTL), graft shrinkage (GS) and gingival margin position (GMP) at 2 weeks, 6 weeks, 3 months, 6 months and 12 months after surgery.

RESULTS

Twenty-nine patients (35 sites) participated in this prospective study. After surgery, KTW decreased and GS increased significantly in both treatment groups during the whole follow-up period, but the biggest changes were observed at 6 weeks. When comparing both treatment groups, implant sites showed significantly more reduction in KTW and more GS. Thus, at 12 months, KTW and GS reduced 2.03 ± 2.1 mm and 36.74 ± 38.2% in the teeth group and 2.91 ± 12.03 mm and 61.8 ± 36.25% around implants, respectively.

CONCLUSIONS

A significantly greater reduction in KTW and more GS might be expected at implant sites.