Evaluation of the safety and efficacy of periodontal applications of a living tissue-engineered human fibroblast-derived dermal substitute. I. Comparison to the gingival autograft: a randomized controlled pilot study

Living cellular constructs for keratinized tissue augmentation: A 13-year follow-up from a split-mouth randomized, controlled, clinical trial

BACKGROUND

A 13-year follow-up was conducted of a short-term investigation of the use of living cellular construct (LCC) versus free gingival graft (FGG) for keratinized tissue width (KTW) augmentation in natural dentition, to evaluate the long-term outcomes and assess the changes occurring since the end of the original 6-month study.

METHODS

Twenty-four subjects out of the original 29 enrolled participants were available at the 13-year follow-up. The primary endpoint was the number of sites demonstrating stable clinical outcomes from 6 months to 13 years (defined as KTW gain, stability, or ≤0.5 mm of KTW loss, together with reduction, stability, or increase of probing depth, and recession depth [REC] ≤0.5 mm). Secondary outcomes included the assessment of KTW, attached gingiva width (AGW), REC, clinical attachment level, esthetics, and patient-reported outcomes at the 13-year visit, assessing the changes from baseline to 6 months.

RESULTS

Nine sites per group (42.9%) were found to have maintained stable (≤0.5 mm or improved) clinical outcomes from 6 months to 13 years. No significant differences were observed for the clinical parameters between LCC and FGG from 6 months to 13 years. However, the longitudinal mixed model analysis showed that FGG delivered significantly better clinical outcomes over 13 years (p < 0.01). LCC-treated sites exhibited superior esthetic outcomes compared to FGG-treated sites at 6 months and 13 years (p < 0.01). Patient-evaluated esthetics were significantly higher for LCC over FGG (p < 0.01). Patient overall treatment preference was also in favor of LCC (p < 0.01).

CONCLUSIONS

A similar stability of the treatment outcomes from 6 months to 13 years was found for LCC- and FGG-treated sites, with both approaches shown to be effective in augmenting KTW and AGW. However, superior clinical outcomes were found for FGG over 13 years, while LCC was associated with better esthetics and patient-reported outcomes than FGG.

Cell-based therapy in the management of Class III Miller's recession - A case report with 45-month follow-up

Miller's Class III gingival recessions (GRs) have always posed a challenge to the clinicians in terms of achieving complete root coverage (CRC). In the present case, a cell-based therapy with autologous fibroblasts seeded onto a Type 1 collagen membrane, through an in-vitro culturing method was utilized. The fibroblasts-seeded membrane was surgically placed under a laterally repositioned flap. The patient presented with a CRC, which was stable even at the postoperative period of 45 months. In addition, a 3-mm substantial gain in the width of keratinized tissue was achieved and maintained throughout the postoperative period. Hence, the results of the cell-seeded therapy emphasize that it can serve as an effective alternative method for the management of Miller's Class III GRs.

Clinical and patient-reported outcomes of tissue engineering strategies for periodontal and peri-implant reconstruction

Scientific advancements in biomaterials, cellular therapies, and growth factors have brought new therapeutic options for periodontal and peri-implant reconstructive procedures. These tissue engineering strategies involve the enrichment of scaffolds with living cells or signaling molecules and aim at mimicking the cascades of wound healing events and the clinical outcomes of conventional autogenous grafts, without the need for donor tissue. Several tissue engineering strategies have been explored over the years for a variety of clinical scenarios, including periodontal regeneration, treatment of gingival recessions/mucogingival conditions, alveolar ridge preservation, bone augmentation procedures, sinus floor elevation, and peri-implant bone regeneration therapies. The goal of this article was to review the tissue engineering strategies that have been performed for periodontal and peri-implant reconstruction and implant site development, and to evaluate their safety, invasiveness, efficacy, and patient-reported outcomes. A detailed systematic search was conducted to identify eligible randomized controlled trials reporting the outcomes of tissue engineering strategies utilized for the aforementioned indications. A total of 128 trials were ultimately included in this review for a detailed qualitative analysis. Commonly performed tissue engineering strategies involved scaffolds enriched with mesenchymal or somatic cells (cell-based tissue engineering strategies), or more often scaffolds loaded with signaling molecules/growth factors (signaling molecule-based tissue engineering strategies). These approaches were found to be safe when utilized for periodontal and peri-implant reconstruction therapies and implant site development. Tissue engineering strategies demonstrated either similar or superior clinical outcomes than conventional approaches for the treatment of infrabony and furcation defects, alveolar ridge preservation, and sinus floor augmentation. Tissue engineering strategies can promote higher root coverage, keratinized tissue width, and gingival thickness gain than scaffolds alone can, and they can often obtain similar mean root coverage compared with autogenous grafts. There is some evidence suggesting that tissue engineering strategies can have a positive effect on patient morbidity, their preference, esthetics, and quality of life when utilized for the treatment of mucogingival deformities. Similarly, tissue engineering strategies can reduce the invasiveness and complications of autogenous graft-based staged bone augmentation. More studies incorporating patient-reported outcomes are needed to understand the cost-benefits of tissue engineering strategies compared with traditional treatments.

Conventional versus flap-protected free gingival graft: a multicenter randomized clinical trial

The purpose of this study was to compare the outcomes of a modified gingival graft technique, in which the released flap is positioned and sutured over the graft, with the conventional free gingival graft (FGG) procedure, when both are used for gingival augmentation. A 12-month, multicenter parallel randomized controlled trial was conducted. Subjects with buccal RT2 gingival recessions and keratinized tissue width (KTW) < 2 mm in at least one mandibular incisor were randomized to control group (n = 20; conventional FGG) or test group (n = 20; modified FGG; flap sutured over FGG using sling sutures). The primary outcome (KTW) was measured at baseline and after 3, 6 and 12 months, as was keratinized tissue thickness (KTT). Postoperative pain (POP) and analgesic intake were also recorded. Both techniques promoted a significant increase in KTW and KTT when compared to baseline (p < 0.05) with no significant differences between groups (KTW change of 6.1±1.5 mm and 5.4±1.6 mm, for control and test, respectively; p=0.16). However, test group patients reported less POP after 7 days and used less analgesic medication than control group patients (p < 0.05). We concluded that the modified FGG was comparable to conventional FGG in augmenting keratinized tissue width and thickness at mandibular incisors, but resulted in less patient morbidity.

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.

State of the art of clinical applications of Tissue Engineering in 2021

Tissue engineering (TE) was introduced almost 30 years ago as a potential technique for regenerating human tissues. However, despite promising laboratory findings, the complexity of the human body, scientific hurdles, and lack of persistent long-term funding still hamper its translation towards clinical applications. In this report, we compile an inventory of clinically applied TE medical products relevant to surgery. A review of the literature, including articles published within the period from 1991 to 2020, was performed according to the PRISMA protocol, using databanks PubMed, Cochrane Library, Web of Science, and Clinicaltrials.gov. We identified 1039 full-length articles as eligible; due to the scarcity of clinical, randomised, controlled trials and case studies, we extended our search towards a broad surgical spectrum. Forty papers involved clinical TE studies. Amongst these, 7 were related to TE protocols for cartilage applied in the reconstruction of nose, ear, and trachea. Nine papers reported TE protocols for articular cartilage, 9 for urological purposes, 7 described TE strategies for cardiovascular aims, and 8 for dermal applications. However, only two clinical studies reported on three-dimensional (3D) and functional long-lasting TE constructs. The concept of generating 3D TE constructs and organs based on autologous molecules and cells is intriguing and promising. The first translational tissue-engineered products and techniques have been clinically implemented. However, despite the 30 years of research and development in this field, TE is still in its clinical infancy. Multiple experimental, ethical, budgetary, and regulatory difficulties hinder its rapid translation. Nevertheless, the first clinical applications show great promise and indicate that the translation towards clinical medical implementation has finally started.

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.

Patient experience of autogenous soft tissue grafting has an implication for future treatment: A 10- to 15-year cross-sectional study

BACKGROUND

Patient-reported outcomes have received a great deal of interest in periodontal plastic procedures. However, their evaluation has mainly been short-term. Thus, the aim of this study was to evaluate the impact of soft tissue grafting procedures conducted over a decade ago on the willingness of a patients to undergo the surgery again.

METHODS

Subjects that received an autogenous soft tissue graft over 10 years ago were screened and invited for a survey. Their response was only analyzed if they were able to correctly identify the sites of the surgical procedures. Dichotomous questions and visual analogue scales (VASs) were used to assess self-reported pain, willingness to retreat and satisfaction.

RESULTS

Fifty-two patients were included in the analyses. Higher pain was reported for mandibular sites, and treated areas including ≥ 3 teeth (P < 0.01). Willingness to retreatment was 84.6% and it was negatively associated with self-reported pain measures, the arch location (mandible), and number of treated sites (≥3 teeth) (P < 0.01). Mean satisfaction rate was 86.9 ± 13.65 (VAS) and showed a positive correlation with willingness to retreat (P < 0.01). Having a complete root coverage at the recall visit was also significantly associated with higher patient satisfaction scores (P < 0.01).

CONCLUSIONS

Patient experience of previous autogenous soft tissue grafting has an influence on their decision to undergo future treatment. Willingness to retreat was negatively affected by mandibular sites, larger treated areas and the perceived pain, while presenting with complete root coverage was significantly associated with patient satisfaction.

Oral Soft Tissue Grafting

The presence of healthy soft tissue at the tooth and implant interface correlates to long-term success and stability in function and esthetics. Grafting procedures utilizing various techniques can be performed during any stage of the implant or restorative therapy. Materials of autogenous, allogeneic, and xenogeneic sources are available for oral soft tissue grafting. This article describes the classifications of soft tissue defects, treatment modalities, and materials used to enhance soft tissue quality and quantity and to achieve optimal esthetics and function around teeth and implants.

Use of Mucograft Collagen Matrix® versus Free Gingival Graft to Augment Keratinized Tissue around Teeth: A Randomized Controlled Clinical Trial

Objectives

This study aimed to evaluate the mucograft collagen matrix (CM) to increase keratinized tissue around teeth compared to free gingival graft (FGG).

Materials and Methods

The present double-blind, randomized, controlled clinical trial studied 12 patients who had 2 mm or less keratinized gingiva bilaterally around mandibular premolars. The 6-month width of keratinized tissue, periodontal parameters (preoperatively and 1, 3, and 6 months postoperatively), color match, pain, and total surgical time were measured.

Results

The mean dimensional change of keratinized gingiva 6 months postoperatively was 4.1±0.7 mm for FGG and 8±1.7 mm for CM. Periodontal parameters were not affected in the two groups. The CM group had a significantly lower pain, experienced less surgery time, and gained better aesthetics compared to the FGG group.

Conclusion

CM appears to be a suitable substitute for FGG in procedures designed to increase keratinized tissue around teeth. It has remarkable benefits, such as acceptable keratinized tissue gain, less pain, less surgical chair time, and better aesthetics.

Digital scanning is more accurate than using a periodontal probe to measure the keratinized tissue width

This study aimed to compare the accuracy and reliability of digital versus conventional clinical measurements of the width of keratinized tissue. To this end, the keratinized tissue width was measured at 110 tooth sites in 5 pig jaws. The measurements were made at each site using three-dimensional (3D) scanned images and a periodontal probe. The actual keratinized tissue width was subsequently measured on histologic slides prepared from the same sites, and differences between the histologic slides and the digital and clinical measurements were analyzed to determine their accuracy in two measurement rounds. Furthermore, intrarater and interrater reliabilities were evaluated using the intraclass correlation coefficient (ICC). Here we show that the mean differences (and lower/upper limits of agreement) between the histologic and the digital/clinical measurements were 0.10 mm (−1.34/1.54 mm) and 1.11 mm (−0.69/2.92 mm), respectively, in the first round of measurements (p < 0.01), and 0.04 mm (−1.52/1.59 mm) and 1.05 mm (−0.37/2.48 mm) in the second round of measurements (p < 0.01). Moreover, we found that the intrarater reliability was higher for the digital measurements (ICC = 0.97, confidence interval [CI] = 0.96–0.97) than for the clinical measurements (ICC = 0.87, CI = 0.86–0.89; p < 0.01). Taken together, our results demonstrate that digital measurements of the keratinized tissue width using 3D scanned images can replace conventional clinical measurements using a periodontal probe since they are more accurate and reliable.

Long-term predictability of allogenic dermal matrix for root coverage: Three years observation period on 15 consecutive cases

Gingival recession is an apical migration of gingival margin that is a common finding on patients with meticulous oral hygiene and periodontitis patients. Several surgical treatment techniques of gingival recession have been described. The most challenging situation is the presence of multiple adjacent recession defects. 15 patients with total of 53 recession defects have been treated with Acellular Dermal Matrix (ADM). The following clinical parameters were evaluated recession depth (RD), probing depth (PD); and the width of the keratinized tissue (KT). Upon completion of the study; there was statistically significant (P-value = 0.00) reduction in recession depth from baseline, one and three years after the surgery (2.6 mm, 0.32 mm, and 0.17 mm, respectively). There was statistically significant (P-value = 0.00) increase in the width of keratinized tissue from baseline to one year and three years (3.47 mm, 5.02 mm, and 5.40 mm, respectively). Based on this study the use of ADM with the coronally advanced flap resulted in a significant increase in keratinized tissue and percentage of root surface coverage.

Three-dimensional cell printing of gingival fibroblast/acellular dermal matrix/gelatin–sodium alginate scaffolds and their biocompatibility evaluation in vitro

3D cell printing of gingival fibroblast/acellular dermal matrix/gelatin–sodium alginate scaffolds showed satisfactory biological properties.

Living cell-based regenerative medicine technologies for periodontal soft tissue augmentation

The cultivation of human living cells into scaffolding matrices has progressively gained popularity in the field of periodontal wound healing and regeneration. Living cellular constructs based on fibroblasts, keratinocytes alone or in combination have been developed and used as alternatives to autogenous soft tissue grafts in keratinized tissue augmentation and in root coverage procedures. Their promising advantages include reduced patient morbidity, unlimited graft availability, and comparable esthetics. This manuscript reviews soft tissue augmentation and root coverage procedures using bioengineered living cellular therapy and highlights their expected clinical, esthetic, and patient-related outcomes.

[Research progress on substitutes for autogenous soft tissue grafts in mucogingival surgery]

Mucogingival surgery is a general term for periodontal surgeries that correct aberrant periodontal soft tissues. Conventional mucogingival surgeries with pedicle flap or autologous soft tissue graft for treatment of gingival recession and insufficient keratinized tissues are always related to disadvantages such as need for a second surgery site, limited supplies, and complaints for postoperative discomfort. In this regard, research and application of soft tissue substitutes have gained increasing attention. Various kinds of soft tissue substitutes, including acellular dermal matrix and xenogeneic collagen matrix, have been developed and applied to clinical treatment. This review aims to summarize advances in research of the characteristics and clinical effectiveness of several soft tissue substitutes and provide references for clinical application.

Soft tissue substitutes in non-root coverage procedures: a systematic review and meta-analysis

OBJECTIVES

The present systematic review compared the effectiveness of soft tissue substitutes (STSs) and autogenous free gingival grafts (FGGs) in non-root-coverage procedures to increase keratinized tissue (KT) width around teeth.

MATERIALS AND METHODS

Included studies fulfilled the following main eligibility criteria: (a) preclinical in vivo or human controlled trials using FGG as control, (b) non-root-coverage procedures, and (c) assessment of KT width. Meta-analysis was performed on the gain in KT width (primary outcome variable) and several secondary variables.

RESULTS

Eight human trials with short observation time evaluating five different STSs were identified. FGG yielded consistently significantly (p < 0.001) larger increase in KT width irrespective whether the comparison regarded an acellular matrix or a tissue-engineered STS. Further, FGG yielded consistently ≥2 mm KT width postoperatively, while use of STS did not, in the few studies reporting on this outcome. On the other hand, STSs resulted in significantly better aesthetic outcomes and received greater patient preference (p < 0.001).

CONCLUSIONS

Based on relatively limited evidence, in non-root-coverage procedures, FGG (1) resulted consistently in significantly larger increase in KT width compared to STS and (2) yielded consistently ≥2 mm KT width postoperatively, while STSs did not. STSs yielded significantly better aesthetic outcomes, received greater patient preference, and appeared safe.

CLINICAL RELEVANCE

Larger and more predictable increase in KT width is achieved with FGG, but STSs may be considered when aesthetics is important. Clinical studies reporting relevant posttreatment outcomes, e.g., postop KT width ≥2 mm, on the long-term (>6 months) are warranted.

Morphological Evaluation of Soft Tissue Augmentation Using Porous Poly-DL-Lactic Acid With Straight Holes

OBJECTIVES

This study investigated the biological reaction to porous poly-DL-lactic acid (PDLLA) scaffolds with holes for soft tissue augmentation.

MATERIALS AND METHODS

The control group was porous PDLLA with a diameter of 5.0 mm and a height of 2.0 mm. For the 2 test groups, 7 holes were drilled from the upper to the lower base of the scaffolds; the holes had diameters of 0.5 and 1.0 mm. A scaffold was placed in the periosteum of the cranium. The height and molecular weight (Mw) of the scaffolds were measured at 4 and 8 weeks. Hematoxylin and eosin staining was used to measure the connective tissue and blood vessel areas.

RESULTS

All groups had similar scaffold heights, but the Mw decreased significantly over time. There were significant differences in the connective tissue and blood vessel areas among the control, 0.5-mm, and 1.0-mm groups at the same time point. The soft tissue was increased by drilling holes in the scaffolds.

CONCLUSION

Porous poly-DL-lactic acid (PDLLA) contributed favorable prognosis for soft tissue. A wider hole was associated with increased connective tissue and blood vessel areas. The scaffold height and Mw were not impacted by size of the holes.

The use of a biostatic fascia lata thigh allograft as a scaffold for autologous human culture of fibroblasts--An in vitro study

The method for covering gingival recession defects and augmenting keratinized gingiva involves the use of autogenuous connective tissue grafts obtained from palatal mucosa in combination with various techniques of flap repositioning or tunnel techniques. In the case of multiple gingival recession defects the amount of connective tissue available for grafting is insufficient. Therefore, the use of substitutes is necessary. The most widely used material in recent years has been the acellular dermal matrix allograft. The disadvantage of its application lies in the absence of cells and blood vessels, which increases incorporation time. Primary cultured human autologic fibroblasts are commonly used to optimize the healing process. The aim of this study was to examine the in vitro biocompatibility of human fascia lata allograft as a new scaffold for primary cultured human autologic fibroblasts. For that, a fibroblast culture obtained from a fragment of gingival tissue taken from the hard palate mucosa of a subject was used. After 14 days the colony cells were inoculated on a fragment of human fascia lata allograft. After a further 7 days of incubation the material was frozen, cut and prepared for histochemical examination. After two weeks of incubation, and 7 days after inoculation on a fragment of fascia lata allograft numerous accumulations of the cultured fibroblast were found that had a typical structure and produced collagen fibres. A human fascia lata allograft can be used as a scaffold for primary cultured human autologic fibroblasts. Further studies should confirm the clinical efficacy of this solution.

Comparative evaluation of the relative efficacy of the free mucosal graft and periosteal fenestration for increasing the vestibular depth - A clinical study

Purpose:

The aim of the present study was to compare the periosteal fenestration (PF) and free mucosal graft (FMG) techniques in mandibular anterior region to increase the vestibular depth.

Methodology:

A total of 20 systemically healthy cases (10 patients in each group) with shallow vestibular depth and reduced width of attached gingiva in lower anterior region were included in the present study. Clinical parameters recorded included Gingival index (GI), Plaque index (PI), Oral hygiene index simplified (OHI S), Vestibular depth (VD), width of attached gingiva and post operative discomfort.

Findings:

The results at the end of 3 months showed that the mean GI, PI, OHI S decreased significantly and remained low throughout the study period. The mean gain in percentage of vestibular depth at the end of 3 months for group 1(PF) was 48.4% with relapse of 7.2% from the baseline. For group 2 (FMG), the mean gain in percentage of vestibular depth at the end of 3 months for was 50% with relapse of 6.2% from the baseline. The mean gain in percentage of attached gingiva at 3 months for group 1 and 2 was 65.9% and 74%, respectively. In comparison of group 1 and 2, group 2 showed better results in terms of increasing the vestibular depth and attached gingiva than group 1 although the intergroup comparison was not statistically significant.

Conclusion:

When aim of the clinician is to treat a patient with shallow vestibule together with reduced width of attached gingiva, the use of periosteal fenestration yields similar results to that of FMG.

Distinct phenotype and therapeutic potential of gingival fibroblasts

Gingiva of the oral mucosa provides a practical source to isolate fibroblasts for therapeutic purposes because the tissue is easily accessible, tissue discards are common during routine clinical procedures and wound healing after biopsy is fast and results in complete wound regeneration with very little morbidity or scarring. In addition, gingival fibroblasts have unique traits, including neural crest origin, distinct gene expression and synthetic properties and potent immunomodulatory functions. These characteristics may provide advantages for certain therapeutic approaches over other more commonly used cells, including skin fibroblasts, both in intraoral and extra-oral sites. However, identity and phenotype of gingival fibroblasts, like other fibroblasts, are still not completely understood. Gingival fibroblasts are phenotypically heterogeneous, and these…fibroblast subpopulations may play different roles in tissue maintenance, regeneration and pathologies. The purpose of this review is to summarize what is currently known about gingival fibroblasts, their distinct potential for tissue regeneration and their potential therapeutic uses in the future.

Evaluating the clinical and esthetic outcome of apically positioned flap technique in augmentation of keratinized gingiva around dental implants

PURPOSE

Dental implants though a successful treatment modality there exists controversies regarding the relationship between the adequacy of the keratinized gingiva (KG) and peri-implant health. The presence of an adequate amount of peri-implant KG reduces gingival inflammation and hence soft-tissue augmentation should be frequently considered. Among the various periodontal plastic surgical procedures, the apically displaced flap increases the width of keratinized tissue with reduced patient morbidity. The current study aims at evaluating the esthetic improvement in KG around dental implants applying apically positioned flap (APF) technique.

MATERIALS AND METHODS

A total of 10 endosseous dental implants were placed in eight systemically healthy patients. APF surgery was performed at the implant site on the buccal aspect either at the time of implant placement (one stage surgical protocol) or during the implant recovery stage (two stage surgical protocols) for increasing the width of KG and reviewed until 12 weeks post-operatively. The width of KG was evaluated at baseline and at the end of 12 weeks after surgery. Paired t-test was performed to evaluate the changes in the width of KG at baseline and at 12 weeks post-operatively. In addition, soft-tissue esthetic outcome was assessed by using visual analog scale (VAS).

RESULTS

The mean width of KG at baseline was 1.47 mm and 12 weeks post-operatively was 5.42 mm. The gain in KG from baseline was 3.95 mm with the P value of 0.000, which was highly statistically significant. The assessment of esthetic outcome using VAS gave an average score of 7.1 indicating good esthetics.

CONCLUSION

The technique of APF yielded a significant improvement in keratinized tissue, which is both functionally and esthetically acceptable.

Evaluating the clinical and esthetic outcome of apically positioned flap technique in augmentation of keratinized gingiva around dental implants

Purpose:

Dental implants though a successful treatment modality there exists controversies regarding the relationship between the adequacy of the keratinized gingiva (KG) and peri-implant health. The presence of an adequate amount of peri-implant KG reduces gingival inflammation and hence soft-tissue augmentation should be frequently considered. Among the various periodontal plastic surgical procedures, the apically displaced flap increases the width of keratinized tissue with reduced patient morbidity. The current study aims at evaluating the esthetic improvement in KG around dental implants applying apically positioned flap (APF) technique.

Materials and Methods:

A total of 10 endosseous dental implants were placed in eight systemically healthy patients. APF surgery was performed at the implant site on the buccal aspect either at the time of implant placement (one stage surgical protocol) or during the implant recovery stage (two stage surgical protocols) for increasing the width of KG and reviewed until 12 weeks post-operatively. The width of KG was evaluated at baseline and at the end of 12 weeks after surgery. Paired t-test was performed to evaluate the changes in the width of KG at baseline and at 12 weeks post-operatively. In addition, soft-tissue esthetic outcome was assessed by using visual analog scale (VAS).

Results:

The mean width of KG at baseline was 1.47 mm and 12 weeks post-operatively was 5.42 mm. The gain in KG from baseline was 3.95 mm with the P value of 0.000, which was highly statistically significant. The assessment of esthetic outcome using VAS gave an average score of 7.1 indicating good esthetics.

Conclusion:

The technique of APF yielded a significant improvement in keratinized tissue, which is both functionally and esthetically acceptable.

Bone repair cells for craniofacial regeneration

Reconstruction of complex craniofacial deformities is a clinical challenge in situations of injury, congenital defects or disease. The use of cell-based therapies represents one of the most advanced methods for enhancing the regenerative response for craniofacial wound healing. Both somatic and stem cells have been adopted in the treatment of complex osseous defects and advances have been made in finding the most adequate scaffold for the delivery of cell therapies in human regenerative medicine. As an example of such approaches for clinical application for craniofacial regeneration, Ixmyelocel-T or bone repair cells are a source of bone marrow derived stem and progenitor cells. They are produced through the use of single pass perfusion bioreactors for CD90+ mesenchymal stem cells and CD14+ monocyte/macrophage progenitor cells. The application of ixmyelocel-T has shown potential in the regeneration of muscular, vascular, nervous and osseous tissue. The purpose of this manuscript is to highlight cell therapies used to repair bony and soft tissue defects in the oral and craniofacial complex. The field at this point remains at an early stage, however this review will provide insights into the progress being made using cell therapies for eventual development into clinical practice.

Tissue integration of collagen-based matrices: an experimental study in mice

OBJECTIVES

To test whether or not tissue integration, biodegradation, and new blood vessel formation in two collagen-based matrices depend on the level of chemical cross-linking.

MATERIAL AND METHODS

Two collagen matrices with high (CM1) and low (CM2) levels of chemical cross-linking were randomly implanted in two pouches in 14 athymic nude mice. Three and 6 weeks later, the animals were euthanized. Histologic and histomorphometric measurements were performed on paraffin-embedded sections.

RESULTS

Both collagen matrices integrated well into the surrounding soft tissues. The level of cross-linking and duration of implantation had an effect on the formation of new blood vessels. More blood vessels (n = in absolute numbers) were found in outer compartments compared to the central compartments of the matrices, reaching 5.6 (CM2) vs. 4.3 (CM1) at 3 weeks, and 5.3 (CM2) vs. 7.3 (CM1) at 6 weeks. Similarly, connective tissue formation increased for both matrices between 3 and 6 weeks, whereas the amount of remaining collagen network gradually decreased over time being more pronounced for CM1 (-50%) compared to CM2 (-15%).

CONCLUSIONS

The degree of cross-linking was negatively correlated for all outcome measures resulting in improved tissue integration, superior matrix stability and enhanced angiogenic patterns for the less cross-linked collagen matrix (CM2) in this experimental study in mice.

Soft tissue volume augmentation by the use of collagen-based matrices in the dog mandible -- a histological analysis

OBJECTIVES

The aim was to test, whether or not soft tissue volume augmentation with a specifically designed collagen matrix (CM), leads to ridge width gain in chronic ridge defects similar to those obtained by an autogenous subepithelial connective tissue graft (SCTG).

MATERIAL AND METHODS

In six dogs, soft tissue volume augmentation was performed by randomly allocating three treatment modalities to chronic ridge defects [CM, SCTG and sham-operated control (Control)]. Dogs were sacrificed at 28 (n = 3) and 84 days (n = 3). Descriptive histology and histomorphometric measurements were performed on non-decalcified sections.

RESULTS

SCTG and CM demonstrated favourable tissue integration, and subsequent re-modelling over 84 days. The overall mean amount of newly formed soft tissue (NMT) plus bone (NB) amounted to 3.8 ± 1.2 mm (Control), 6.4 ± 0.9 mm (CM) and 7.2 ± 1.2 mm (SCTG) at 28 days. At 84 days, the mean NMT plus NB reached 2.4 ± 0.9 mm (Control), 5.6 ± 1.5 mm (CM) and 6.0 ± 2.1 mm (SCTG). Statistically significant differences were observed between CM/SCTG and Control at both time-points (p < 0.05).

CONCLUSION

Within the limits of this animal model, the CM performed similar to the SCTG, based on histomorphometric outcomes combining NB and NMT.

Future Prospects for Periodontal Bioengineering Using Growth Factors

Polypeptide growth factors have demonstrated strong potential to repair defects associated with teeth and dental implants. Over the past two decades, intense research efforts have led to the clinical development of several growth factors or biologic agents, including bone morphogenetic proteins, platelet-derived growth factor, fibroblast growth factors, and enamel matrix proteins. Several of these growth factors are now being used clinically for a variety of applications, such as the promotion of periodontal regeneration, sinus floor augmentation, and root coverage procedures. Although clinical results have been promising and growth factors add another dimension to clinical care, optimization of growth factor targeting approaches to periodontal wounds remains a challenge. Enhancement of growth factor local application to improve bioavailability, bioactivity, and allowance of three-dimensional reconstruction of complex anatomic defects is a goal. This article will highlight developments for growth factor delivery to better stimulate the wound healing response for periodontal and bone regeneration in the maxillofacial region.

Cell- and gene-based therapeutic strategies for periodontal regenerative medicine

Inflammatory periodontal diseases are a leading cause of tooth loss and are linked to multiple systemic conditions, such as cardiovascular disease and stroke. Reconstruction of the support and function of affected tooth-supporting tissues represents an important therapeutic endpoint for periodontal regenerative medicine. An improved understanding of periodontal biology coupled with current advances in scaffolding matrices has introduced novel treatments that use cell and gene therapy to enhance periodontal tissue reconstruction and its biomechanical integration. Cell and gene delivery technologies have the potential to overcome limitations associated with existing periodontal therapies, and may provide a new direction in sustainable inflammation control and more predictable tissue regeneration of supporting alveolar bone, periodontal ligament, and cementum. This review provides clinicians with the current status of these early-stage and emerging cell- and gene-based therapeutics in periodontal regenerative medicine, and introduces their future application in clinical periodontal treatment. The paper concludes with prospects on the application of cell and gene tissue engineering technologies for reconstructive periodontology.

Gingival and dermal fibroblasts: their similarities and differences revealed from gene expression

Gene expression profiles in normal human gingival and dermal fibroblasts were investigated using DNA microarrays. Their fundamental characteristics were almost identical, but 5% of their genes were uniquely expressed. These results help us to choose an optimal cell source for effective fibroblast-based cell therapy that is dependent on differential gene expression profiles.