Effectiveness of adjunctive hyaluronic acid application in coronally advanced flap in Miller class I single gingival recession sites: a randomized controlled clinical trial

Adjunctive use of hyaluronic acid in the treatment of gingival recessions: a systematic review and meta-analysis

OBJECTIVES

To explore the efficacy of Hyaluronic acid as an adjunctive in treatment of gingival recessions (GR).

MATERIALS AND METHODS

A systematic literature search was performed in several electronic databases, including Medline/ PubMed, Embase, CENTRAL and LILACS. Recession improvement was evaluated through multiple outcome variables. The Cochrane Risk of Bias tool and the ROBINS-I tool were used to assess the quality of the included trials. Weighted Mean Differences (WMDs) and 95% confidence intervals (CIs) between test and control sites were estimated through meta-analysis using a random-effect model for the amount of Relative Root Coverage (RRC).

RESULTS

A total of 3 randomised studies were deemed as eligible for inclusion. Their data were also used for pooling the effect estimates. Overall analysis of RRC (3 studies) presented a WMD of 7.49% (p = 0.42; 95% CIs -10.88, 25.86) in favour of adjunctive use of hyaluronic acid during Coronally Advanced Flap (CAF) technique, although statistical significance was not reached. Statistical heterogeneity was found to be high (I2 = 80%).

CONCLUSIONS

Within their limitations, the present data indicate that the local application of Hyaluronic acid does not lead to additional clinical benefits when used as an adjunctive to the treatment of GR with CAF. However, due to the high heterogeneity among the studies, additional well-designed RCTs are needed to provide further evidence on this clinical indication for the use of Hyaluronic acid.

CLINICAL RELEVANCE

In the frame of the current review, the adjunctive use of Hyaluronic acid does not additionally improve the clinical outcomes obtained during treatment of GR with CAF.

Healing of Periodontal Suprabony Defects following Treatment with Open Flap Debridement with or without Hyaluronic Acid (HA) Application

Background and Objectives: This randomized, double-arm, multicentric clinical trial aims to compare the clinical outcomes following the treatment of suprabony periodontal defects using open flap debridement (OFD) with or without the application of hyaluronic acid (HA). Materials and Methods: Sixty systemically healthy patients with at least two teeth presenting suprabony periodontal defects were randomly assigned with a 1:1 allocation ratio using computer-generated tables into a test (OFD + HA) or control group (OFD). The main outcome variable was clinical attachment level (CAL). The secondary outcome variables were changes in mean probing pocket depth (PPD), gingival recession (GR), full-mouth plaque score (FMPS), and full-mouth bleeding score (FMBS). All clinical measurements were carried out at baseline and 12 months. Results: Sixty patients, thirty in each group, were available for statistical analysis. The mean CAL gain was statistically significantly different (p < 0.001) in the test group compared with the control group (3.06 ± 1.13 mm vs. 1.44 ± 1.07 mm). PPD reduction of test group measurements (3.28 ± 1.14 mm) versus the control group measurements (2.61 ± 1.22 mm) were statistically significant (p = 0.032). GR changes were statistically significant only in the test group 0.74 ± 1.03 mm (p < 0.001). FMBS and FMPS revealed a statistically significant improvement mostly in the test group. Conclusions: Suprabony periodontal defects could benefit from the additional application of HA in conjunction with OFD in terms of improvement of the clinical parameters compared with OFD alone.

Immunohistochemical study of mixing mineral trioxide aggregate with hyaluronic acid as a pulp-capping agent in dog teeth

Objective

The purpose of this study was to evaluate the immunohistochemical effect of hyaluronic acid (HA) on the mineralization rate of the reparative dentin when it is used as a mixing medium with mineral trioxide aggregate (MTA).

Materials and Methods

Direct pulp capping (DPC) was performed on 90 teeth from 10 dogs that had been experimentally exposed. The exposed pulps were divided into three groups according to the mixing medium with MTA: Group I: MTA + distilled water (control group), Group II: MTA + hybrid cooperative complex HA (HCC-HA), Group III: MTA + high molecular weight HA (HMW-HA). After pulp capping, all cavities were restored with final restoration. The dogs were divided randomly into five groups (two dogs each) according to the evaluation periods (7, 14, 21, 30, and 60) days. At the end of the study, the dogs were euthanized, and the sampled teeth were processed for immunohistochemical investigation.

Results

Both types of HA (HCC-HA, HMW-HA) showed an increase in the expression of alkaline phosphatase (ALP) at a higher rate than using distilled water with MTA.

Conclusions

Within the limitations of this study, HA proved to be an effective additive to MTA for DPC.

Hyaluronic acid in Dentoalveolar regeneration: Biological rationale and clinical applications

Background

Hyaluronic acid (HA) is found in different locations in the periodontium, including mineralized tissues (i.e., cementum and alveolar bone) and non-mineralized tissues (i.e., gingiva and periodontal ligament). In addition, it seems to play an essential part in regulating the underlying mechanisms involved in tissue inflammatory reactions and wound healing. HA has the potential to regulate periodontal tissue regeneration and treat periodontal disease.

Aim

The current review of the literature was conducted to assess how HA plays its part in periodontal therapy and examine the contemporary literature's viewpoint on its use in periodontal regeneration.

Conclusion

HA has a multifunctional character in periodontal regeneration, and healing and appears to provide promising outcomes in different periodontal regenerative applications.

Evaluation of hyaluronic acid gel with or without acellular dermal matrix allograft in the treatment of class II furcation defects in dogs: A histologic and histomorphometric study

Aim

To evaluate the histologic and histomorphometric effects of hyaluronic acid (HA) gel with or without acellular dermal matrix allograft (ADMA) on periodontal regeneration in Class II furcation defects in dogs.

Materials and methods

Class II furcation defects were surgically created in the mandibular first and second premolars bilaterally in eight beagle dogs. The Class II furcation defects were assigned randomly, using the split-mouth design, into the test and control sides. The teeth on the test sides were equally and randomly divided into the HA/ADMA group (n = 8) treated with 0.8% HA gel followed by ADMA, and the HA-only group (n = 8) treated with 0.8% HA only. The furcation defects of the control sides (n = 16) were subjected to open flap debridement (OFD group). The animals were euthanized for histologic and histomorphometric analyses after one month (n = 4) and three months (n = 4).

Results

At one month, the newly formed bone area (NFBA) was larger in the HA/ADMA (6.23 ± 1.41 mm2) and HA-only (5.90 ± 1.43 mm2) groups than in the OFD group (2.42 ± 1.62 mm2) (p < 0.05). The newly formed cementum (NFAC) and periodontal ligament (NFPL) were similar in the HA/ADMA and HA-only groups but significantly lesser in the OFD group (p < 0.05.) At three months, the NFBA, NFAC, and NFPL were greater in the HA/ADMA group than in the HA-only group (p < 0.05). New regenerative tissue was significantly greater in both the test groups than in the OFD group (p < 0.05), while epithelial downgrowth predominated the healing in the latter.

Conclusions

These results suggest that HA with ADMA positively affects the periodontal regeneration and wound healing in Class II furcation defects.

In vitro activity of hyaluronic acid and human serum on periodontal biofilm and periodontal ligament fibroblasts

OBJECTIVES

A beneficial effect of cross-linked hyaluronic acid (cHA) on periodontal wound healing and regeneration has recently been demonstrated. The present in vitro study was designed to obtain deeper knowledge on the effect of cHA when applied in the gingival sulcus (serum-rich environment) during non-surgical periodontal therapy.

MATERIALS AND METHODS

The influence of cHA, human serum (HS), and cHA/HS on (i) a 12-species biofilm formation, (ii) the adhesion of periodontal ligament fibroblasts (PDLF) to dentine surface, (iii) the expression and secretion of interleukin-8, and (iv) the expression of receptors of HA in PDLF and gingival fibroblasts (GF) were evaluated.

RESULTS

At 4 h of biofilm formation, cHA and HS in combination (cHA/HS) slightly decreased the colony-forming unit counts in biofilm whereas the metabolic activity of biofilm was reduced in all test groups (cHA, HS, cHA/HS) vs. control. At 24 h, the quantity of biofilm was reduced in all test groups vs. untreated control. The test substances did not affect adhesion of PDLF to dentin. HS increased the expression of IL-8 by PDLF and GF which was partially downregulated by cHA. HS and/or cHA promoted the expression of the HA receptor RHAMM in GF but not in PDLF.

CONCLUSIONS

In summary, the present data indicate that serum neither negatively affect the activity of cHA against periodontal biofilm nor had any unwanted influence on the activity of PDLF.

CLINICAL RELEVANCE

These findings lend additional support for the positive effects of cHA on cells involved in periodontal wound healing, thus pointing to its potential use in non-surgical periodontal therapy.

Efficacy of Hyaluronic Acid in Relieving Post-implantation Pain: A Split-Mouth Randomized Controlled Trial

Background

Many patients suffer from some degree of pain following the surgical procedures of dental implantation. The fear of pain may be one reason for postponing such prosthodontic treatments. Many procedures have been suggested to control post-implantation pain. This trial evaluated the effectiveness of using hyaluronic acid (HA) during dental implantation on patients’ perceived pain during the postsurgical soft-tissue healing period.

Methodology

A split-mouth randomized controlled trial (RCT) was conducted. The trial sample consisted of 22 dental implants in 11 patients (five males and six females). Patients were selected from those attending the Department of Oral Medicine at the Faculty of Dentistry, University of Damascus between February 2021 and May 2022. The implants were performed in similar bone quality and density for each patient as the implants were inserted in the same jaw on both sides to ensure the same physiological conditions. The study sample was divided into two groups. The first group (the experimental group) consisted of 11 implants in which the implant site was drilled, following which HA was placed inside the implant site and on the surrounding bone before the flap was returned and sutured. The second group (the control group) comprised 11 implants following the conventional procedure without applying any material to the implant socket. The main outcome measure was pain perception which was assessed using the visual analog scale (VAS). Patients were asked to record their perceived pain on the first, third, and tenth days. Two-sample t-tests were used to detect significant differences.

Results

There were statistically significant differences in the mean pain intensity between the experimental and control groups on the first, third, and tenth days (p < 0.05). The mean values of perceived pain in the control group were 5.68, 1.72, and 0.56 on the first, third, and tenth days, respectively. In comparison, the mean values of perceived pain in the experimental group were 4.52, 1.14, and 0.18 on the first, third, and tenth days, respectively. The maximum perceived pain in the control group was 7.5 on the first day following implantation, whereas the maximum value recorded in the experimental group was 6.5. At the third assessment time (i.e., 10 days following the surgical intervention), the mean values were in the very mild category of pain intensity.

Conclusions

This study showed that applying HA in the implant cavity and on the surrounding bone effectively reduced pain after dental implant surgery in comparison with the control group. Patients had lower mean pain scores at one, three, and ten days following surgery compared to the conventional method. HA is suggested to be an adjunctive method to control postsurgical pain after dental implantation.

Tunnel technique with cross-linked hyaluronic acid in addition to subepithelial connective tissue graft, compared with connective tissue graft alone, for the treatment of multiple gingival recessions: 6-month outcomes of a randomized clinical trial

OBJECTIVES

The aim of this study was to investigate differences in clinical and esthetic outcomes in the treatment of multiple gingival recession types 1 and 2, using the modified coronally advanced tunnel technique (MCAT) combined with subepithelial connective tissue graft (SCTG), with or without cross-linked hyaluronic acid (HA).

MATERIALS AND METHODS

A total of 24 patients with 266 multiple gingival recessions (GR) were enrolled in the study (133 recessions per group). MCAT was combined with SCTG and HA on the test side, while MCAT with SCTG was used on the control side. Clinical parameters were measured at baseline and 6 months post-operatively. Visual analogue scales (VAS) and questionnaires were used to assess patient-rated outcomes, and the root coverage esthetic score (RES) was used for professional esthetic evaluation.

RESULTS

No significant improvement in root coverage was observed as a result of adding HA. After 6 months, mean root coverage (MRC) was 85% for SCTG + HA group and 83% for SCTG group (p = 0.9819). Complete root coverage (CRC) was observed in 91% (test) and 93% (control) of the cases (p = 0.9001). Professional assessment of soft tissue texture (STT) using RES showed a significant difference (0.94 versus 0.69, p = 0.0219) in favor of the experimental group.

CONCLUSIONS

Both treatments were similarly effective in treating multiple GRs and led to comparable improvements in clinical parameters. However, application of HA improved the appearance of soft tissue texture.

CLINICAL RELEVANCE

Adjunctive application of HA in the MCAT + SCTG procedure may improve STT results.

Clinical efficacy of hyaluronic acid in the treatment of periodontal intrabony defect: a systematic review and meta-analysis

OBJECTIVE

This systematic review aimed to evaluate the effects of hyaluronic acid (HA) alone or in combination with any bone substitute for the treatment of intrabony defects (IBDs).

MATERIAL AND METHODS

Six databases were searched up to April 2022 to find randomized clinical trials comparing the clinical effects of open flap debridement (OFD) + HA versus OFD alone (first group) or OFD + HA + bone substitutes versus OFD + bone substitutes (second group) in the treatment of IBDs with a follow-up of at least 3 months. Random effects models of mean differences were used to determine the clinical attachment level (CAL) gain, probing depth (PD) reduction, and radiographic bone fill (RBF).

RESULTS

Of the 276 studies identified, 6 were included in the qualitative synthesis, and 5 in the meta-analyses. The meta-analyses in the first group showed a statistically significant differences for CAL gain (mean difference [MD]:1.00; 95% confidence interval [CI]:0.65 - 1.35; n = 2) and PD reduction (MD: 0.76; 95%CI: 0.34 - 1.17; n = 2) favoring HA + OFD at 6 months. However, in the second group, the meta-analyses did no show additional effect of HA in association with bone substitute was demonstrated for either CAL gain (MD: 0.57; 95%CI: - 0.30 - 1.43; n = 2) or PD reduction (MD: 1.05; 95%CI: - 0.38 - 2.47; n = 2) but did show significant differences for RBF (MD: 0.57; 95%CI: 0.15 - 0.99; n = 2) at 12 months.

CONCLUSION

Compared with OFD alone, local application of HA in the treatment of IBDs provided a significant CAL gain and PD reduction at 6 months. However, its combination with bone substitutes showed no statistically significant differences at 12 months.

CLINICAL RELEVANCE

The use of OFD + HA improves the CAL and PD in the treatment of IBDs compared to OFD only after 6 months of follow-up. These results are not maintained after 12 months.

Hyaluronic Acid: A New Approach for the Treatment of Gingival Recession-A Systematic Review

This systematic review aimed to investigate the effectiveness of hyaluronic acid (HA) on the clinical treatment outcomes of patients with gingival recession. A systematic search was performed in PubMed, Cochrane Central Register of Controlled Trials, Embase, Scopus, and Google Scholar for studies up to 15 August 2022. Two reviewers separately selected the papers for eligibility after conducting a thorough search. The study includes randomized controlled clinical trials in which participants were given HA in addition to periodontal treatment surgical procedures. The changes following the treatment protocol were evaluated for complete and mean root coverage as a primary outcome and gingival recession gain as the secondary outcome. Three articles met the eligibility criteria out of 557 titles. In periodontal surgery, HA exhibited better results in complete root coverage and mean root coverage when compared to the control group. Gingival recession reduction, clinical attachment level, and keratinized tissue gain were significantly increased compared to the control groups. However, the comparison presented in the following study might show heterogeneity among the studies and risk of bias in general. Given the scope of this analysis, results suggest that adjunctive treatment with HA gel for root coverage could be clinically beneficial.

Cross-linked hyaluronic acid gel with or without a collagen matrix in the treatment of class III furcation defects: A histologic and histomorphometric study in dogs

AIM

To histologically evaluate the effects of cross-linked hyaluronic acid (xHyA) with or without a collagen matrix (CM) on periodontal wound healing/regeneration in class III furcation defects in dogs.

MATERIALS AND METHODS

Class III furcation defects were surgically created in the mandibular premolars in six beagle dogs. The defects were randomly treated as follows: open flap debridement (OFD) + CM (CM), OFD + xHyA (xHyA), OFD + xHyA + CM (xHyA/CM) and OFD alone (OFD). At 10 weeks, the animals were euthanized for histological evaluation.

RESULTS

The newly formed bone areas in the xHyA (4.04 ± 1.51 mm² ) and xHyA/CM (4.32 ± 1.14 mm² ) groups were larger than those in the OFD (3.25 ± 0.81 mm² ) and CM (3.31 ± 2.26 mm² ) groups. The xHyA (6.25 ± 1.45 mm) and xHyA/CM (6.40 ± 1.35 mm) groups yielded statistically significantly (p < .05) greater formation of new connective tissue attachment (i.e., new cementum, with inserting connective tissue fibres) compared with the OFD (1.47 ± 0.85 mm) group. No significant differences were observed in any of the histomorphometric parameters between the xHyA and xHyA/CM groups. Complete furcation closure was not observed in any of the four treatment modalities.

CONCLUSIONS

Within their limits, the present results suggest that the use of xHyA with or without CM positively influences periodontal wound healing in surgically created, acute-type class III furcation defects.

Hyaluronic Acid as an Adjunct to Coronally Advanced Flap Procedures for Gingival Recessions: A Systematic Review and Meta—Analysis of Randomized Clinical Trials

Previous systematic reviews have reported that coronally advanced flap (CAF) + connective tissue graft (CTG) are the gold standard in root coverage procedures (RCP). Nevertheless, adjunctive treatment with hyaluronic acid (HA) has been proposed to aim at improving clinical outcomes and reducing patient morbidity. The aim of this systematic review and meta-analysis is to compare the use of HA as an adjunctive treatment to CAF procedures in Miller class I and II (recession type 1; RT1) gingival recession (GR) defects treatment with no adjunctive/other treatments. MEDLINE, The Cochrane Central Register of Controlled Trials, Web of Science, Scopus databases and gray literature were searched up to April 2022. The primary outcome variables were mean recession coverage (MRC) and reduction of the recession depth (RecRed). Weighted mean differences and 95% confidence intervals between treatments were estimated using a random-effect mode. From 264 titles identified, 3 RCTs reporting 90 GR defects in 60 patients were included. Overall analysis of MRC and RecRed were 0.27% (p = 0.01) and 0.40 mm (p = 0.45) in favor of CAF + HA compared to CAF alone/CAF + subepithelial connective tissue graft (SCTG), respectively, with a statistically significant difference only for MRC values. Nevertheless, due to the limited number and heterogeneity of the included studies, well-performed RCTs are needed to clarify a potential advantage of HA in RCPs in the future.

Hyaluronic acid injection to restore the lost interproximal papilla: a systematic review

OBJECTIVES

To assess the efficacy and safety of hyaluronic acid (HA) injections to restore the lost interproximal papilla.

MATERIALS AND METHODS

A systematic literature search was conducted in PubMed/MEDLINE, Scopus and Cochrane electronic databases with no time restriction up to September 2021. Any clinical study evaluating HA injection into the interproximal papilla loss Class I and II according to Norland & Tarnow, were included based on the following PICO questions (1) Are HA injections effective for the reconstruction of the interproximal papilla loss? (2) What are the side/adverse effects of using HA for the reconstruction of interproximal papilla loss? The risk of bias assessment was performed using the Cochrane Collaboration's the Newcastle Ottawa and Joanna Briggs institute tools.

RESULTS

A total of 1497 titles were retrieved. From these, eleven were included and underwent full data extraction. However, due to heterogeneity in the data among the included articles, a meta-analysis could not be performed. Three articles reported no-differences in term of papilla tip to contact point distance or the papilla fill reduction. Finally, five studies showed a reduction in the black triangle with a percentage range between 19 and 47%.

CONCLUSION

The non-surgical use of HA injection seems to have a positive effect on the re-establishment of interproximal papilla lost. However post-operative complications might develop.

Effectiveness of acellular dermal matrix graft with a coronally advanced flap for the treatment of Miller Class I/II single gingival recession with thin gingival phenotype: study protocol for a split-mouth randomised controlled trial

INTRODUCTION

Gingival recession is one of the most common mucogingival deformities requiring surgical correction. The American Academy of Periodontology Regeneration Workshop recommended connective tissue graft (CTG) combined with coronally advanced flap (CAF) for the treatment of Miller Class I and II single-tooth gingival recession. The disadvantages of harvesting autogenous tissue include postoperative bleeding, pain and discomfort at the donor site, restricted tissue supply, increased morbidity and prolonged operative times. Acellular dermal matrix (ADM) contains undamaged collagen and elastin matrices that can be used as a substitute for CTG during root coverage procedures. However, the use of ADM is still controversial. The objective of this split-mouth; randomised, controlled, clinical study is to evaluate the long-term effects of ADM graft (ADMG) combined with CAF on root coverage, aesthetics and patient satisfaction for the treatment of single gingival recession with thin gingival phenotype.

METHODS AND ANALYSIS

Forty participants with bilateral Miller Class I/II gingival recession will be randomised to receive an ADMG on one side and CTG on the contralateral side, combined with CAF. Gingival recession depth, gingival recession width and keratinised tissue width will be measured at baseline, 2 weeks and 1, 3, 6, 12 and 24 months. Mean root coverage, complete root coverage, root coverage aesthetic score, colour change (∆E) and patient satisfaction will be assessed during follow-up visits.

ETHICS AND DISSEMINATION

The present study has received approval from the Ethics Committee of Peking University School and Hospital of Stomatology (PKUSSIRB-202054029). Data of this study will be registered with the International Clinical Trials Registry Platform. Additionally, we will disseminate the results through scientific journal.

TRIAL REGISTRATION NUMBER

ChiCTR2000033230.

Stability of biomaterials used in adjunct to coronally advanced flap: A systematic review and network meta-analysis

AIM

The objective of this network meta-analysis was to rank different biomaterials used in adjunct to coronally advanced flap (CAF), based on their performance in root-coverage for Miller's Class I and II gingival recessions.

MATERIALS AND METHODS

An electronic database search was carried out in PUBMED, CENTRAL, SCOPUS, and EMBASE to identify the eligible articles and compiled into the citation manager to remove the duplicates. The primary outcome was keratinized gingival tissue width (KGW) and percentage of root coverage (%RC). The treatment effect of different biomaterials was estimated using predictive interval plots and ranked based on biomaterials performance, using multidimensional scale ranking.

RESULTS

CAF + connective tissue graft (CTG), CAF + platelet concentrate matrix (PCM) and acellular dermal matrix (ADM) ranked at the top positions in performance in improving KGW. The highest ranked materials in improving percentage of root coverage in gingival recession were CAF + collagen matrix (CM) + gingival fibroblasts (GF), CAF + ADM + platelet rich plasma (PRP) and CAF + ADM, as compared to CAF alone.

CONCLUSION

CTG, ADM, platelet concentrates, and CM + GFs, when used in adjunct to CAF, showed improved stability over ≥12 months of follow-up, better percentage of root coverage, and improved keratinized gingival width.

Soft Tissue Regeneration at Natural Teeth

This article provides an overview of the best-documented surgical techniques for recession coverage and draws conclusions for the clinician. Use of a connective tissue graft with either coronally advanced flap (CAF) or tunnel is the most predictable technique for the treatment of single and multiple gingival recessions. Long-term results exist only for CAF with/without connective tissue graft providing evidence for long-term stability with only minor relapses. Soft tissue replacement materials and biologics may represent a valuable modality to additionally improve the clinical outcomes obtained with CAF alone or, in certain clinical situations, to serve as an alternative to autogenous tissue.

Biomolecules in Dental Applications: Randomized, Controlled Clinical Trial Evaluating the Influence of Hyaluronic Acid Adjunctive Therapy on Clinical Parameters of Moderate Periodontitis

The biological activity of hyaluronic acid (HA) has been well-researched during the past decades; however, there are few randomized, controlled trials of its clinical effects in periodontal therapy. The purpose of this study was to evaluate the effect of hyaluronic acid on the principal parameters of periodontal healing. A specific, commercially available formulation designed and registered for professional dental application, composed of 16 mg/mL of cross-linked and 2 mg/mL of non-cross-linked HA, was used as an adjunctive to non-surgical periodontal therapy, and clinical parameters were evaluated after 3 months. The addition of HA to periodontal therapy demonstrated more favorable clinical results regarding reduction in inflammation, measured by bleeding on probing (-6% compared to the control group) and gain in periodontal attachment (1 mm more than control group), while it had no effect on probing depth reduction. No side effects were reported. Our study demonstrated that HA is a safe and easy-to-use biological agent; due to its wide array of properties, it may significantly improve the results of periodontal therapy. However, more long-term studies are needed to investigate whether these favorable effects remain over time.

Local application of hyaluronic acid in conjunction with free gingival graft: a randomized clinical trial

OBJECTIVES

To assess the effect of the application of hyaluronic acid (HA) in conjunction with free gingival graft (FGG) on postoperative patient discomfort and wound healing.

MATERIALS AND METHODS

A total of 24 healthy non-smoker patients requiring FGG were recruited for the study. Subjects were randomly assigned into study groups, local application of HA on both donor and recipient sites and control group, application of normal saline. The FGG dimensions were evaluated using digital photographs. Post-operative pain was evaluated for 14 days. Color matching and patient satisfaction were evaluated at 6 months.

RESULTS

In this randomized clinical trial, 21 patients (mean age 23 years, (15 females and 6 males) completed the study. Baseline characteristics were comparable across treatment groups. Pain scores in donor sites were statistically significant and higher in control group than study group until day 7 (p < 0.05). Mean of the surface area of the graft at baseline in study vs control group were (169 ± 21), (183 ± 22) (2 mm), respectively. While at 6 months, were (147 ± 30) and (139 ± 32) (2 mm), in study and control group, respectively (p > 0.05). Color match showed no statistical significance difference.

CONCLUSIONS

Topical application of HA may exhibit significant improvement of postoperative pain and no significant difference in graft dimensions and patients' satisfaction.

CLINICAL RELEVANCE

Topical application of HA is recommended as a dressing material in FGG surgeries to reduce postoperative pain and accelerate healing.

Cross-linked hyaluronic acid slows down collagen membrane resorption in diabetic rats through reducing the number of macrophages

OBJECTIVES

We previously showed that accelerated degradation of collagen membranes (CMs) in diabetic rats is associated with increased infiltration of macrophages and blood vessels. Since pre-implantation immersion of CMs in cross-linked high molecular weight hyaluronic acid (CLHA) delays membrane degradation, we evaluated here its effect on the number of macrophages and endothelial cells (ECs) within the CM as a possible mechanism for inhibition of CM resorption.

MATERIALS AND METHODS

Diabetes was induced with streptozotocin in 16 rats, while 16 healthy rats served as control. CM discs were labeled with biotin, soaked in CLHA or PBS, and implanted under the scalp. Fourteen days later, CMs were embedded in paraffin and the number of macrophages and ECs within the CMs was determined using antibodies against CD68 and transglutaminase II, respectively.

RESULTS

Diabetes increased the number of macrophages and ECs within the CMs (∼2.5-fold and fourfold, respectively). Immersion of CMs in CLHA statistically significantly reduced the number of macrophages (p < 0.0001) in diabetic rats, but not that of ECs. In the healthy group, CLHA had no significant effect on the number of either cells. Higher residual collagen area and membrane thickness in CLHA-treated CMs in diabetic animals were significantly correlated with reduced number of macrophages but not ECs.

CONCLUSIONS

Immersion of CM in CLHA inhibits macrophage infiltration and reduces CM degradation in diabetic animals.

CLINICAL RELEVANCE

The combination of CLHA and CM may represent a valuable approach when guided tissue regeneration or guided bone regeneration procedures are performed in diabetic patients.

Treatment of Residual Periodontal Pockets Using a Hyaluronic Acid-Based Gel: A 12 Month Multicenter Randomized Triple-Blinded Clinical Trial

The aim of the present study was to evaluate the adjunctive effect of hyaluronic acid (HA) gel in the treatment of residual periodontal pockets over a 12-month period. Periodontal patients presenting at least one residual periodontal pocket 5-9 mm of depth in the anterior area were recruited from six university-based centers. Each patient was randomly assigned to subgingival instrumentation (SI) with the local adjunctive use of HA for test treatment or adjunctive use of local placebo for control treatment at baseline and after 3 months. Clinical parameters ( )probing depth (PD), bleeding on probing (BoP), plaque index (PI), recession (REC), clinical attachment level (CAL)) and microbiological samples for the investigation of the total bacterial count (TBC) and presence of specific bacterial species (Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Fusobacterium nucleatum) were taken at baseline and every 3 months, until study termination. PD was determined as the primary outcome variable. From a total of 144 enrolled, 126 participants (53 males, 73 females) completed the entire protocol. Both treatments resulted in statistically significant clinical and microbiological improvements compared to baseline. Although the local application of HA showed a tendency for better results, there was a lack of statistically significant differences between the groups.

Polymer-Based Carriers in Dental Local Healing-Review and Future Challenges

Polymers in drug formulation technology and the engineering of biomaterials for the treatment of oral diseases constitute a group of excipients that often possess additional properties in addition to their primary function, i.e., biological activity, sensitivity to stimuli, mucoadhesive properties, improved penetration of the active pharmaceutical ingredient (API) across biological barriers, and effects on wound healing or gingival and bone tissue regeneration. Through the use of multifunctional polymers, it has become possible to design carriers and materials tailored to the specific conditions and site of application, to deliver the active substance directly to the affected tissue, including intra-periodontal pocket delivery, and to release the active substance in a timed manner, allowing for the improvement of the form of application and further development of therapeutic strategies. The scope of this review is polymeric drug carriers and materials developed from selected multifunctional groups of natural, semi-synthetic, and synthetic polymers for topical therapeutic applications. Moreover, the characteristics of the topical application and the needs for the properties of carriers for topical administration of an active substance in the treatment of oral diseases are presented to more understand the difficulties associated with the design of optimal active substance carriers and materials for the treatment of lesions located in the oral cavity.

Influence of Materials Properties on Bio-Physical Features and Effectiveness of 3D-Scaffolds for Periodontal Regeneration

Periodontal diseases are multifactorial disorders, mainly due to severe infections and inflammation which affect the tissues (i.e., gum and dental bone) that support and surround the teeth. These pathologies are characterized by bleeding gums, pain, bad breath and, in more severe forms, can lead to the detachment of gum from teeth, causing their loss. To date it is estimated that severe periodontal diseases affect around 10% of the population worldwide thus making necessary the development of effective treatments able to both reduce the infections and inflammation in injured sites and improve the regeneration of damaged tissues. In this scenario, the use of 3D scaffolds can play a pivotal role by providing an effective platform for drugs, nanosystems, growth factors, stem cells, etc., improving the effectiveness of therapies and reducing their systemic side effects. The aim of this review is to describe the recent progress in periodontal regeneration, highlighting the influence of materials' properties used to realize three-dimensional (3D)-scaffolds, their bio-physical characteristics and their ability to provide a biocompatible platform able to embed nanosystems.

Healing of buccal gingival recessions following treatment with coronally advanced flap alone or combined with a cross-linked hyaluronic acid gel. An experimental study in dogs

Aim

To clinically and histologically evaluate in dogs the healing of gingival recessions treated with coronally advanced flap (CAF) with or without cross‐linked hyaluronic acid (HA).

Materials and methods

Gingival recession defects were surgically created on the vestibular side of both maxillary canines in 8 dogs. After 8 weeks of plaque accumulation, the 16 chronic defects were randomly treated with either CAF alone or CAF and HA‐gel (CAF/HA). Clinical and histological outcomes were evaluated at 10 weeks post‐surgically.

Results

Compared to baseline, the clinical measurements at 10 weeks revealed a statistically significant decrease in gingival recession for both CAF (p < 0.01) and CAF/HA (p < 0.001) groups. Statistically significant differences were found in clinical attachment level (p < 0.05) and width of gingival recession (p < 0.01) favouring the CAF/HA group. Bone formation was statistically significantly greater in the CAF/HA group than in the CAF group (1.84 ± 1.16 mm vs., 0.72 ± 0.62 mm, respectively, p < 0.05). Formation of cementum and connective tissue attachment were statistically significantly higher in the CAF/HA group compared with the CAF group (i.e. 4.31 ± 1.78 mm versus 2.40 ± 1.35 mm and 1.69 ± 0.98 mm versus 0.74 ± 0.68 mm, respectively (p < 0.05)).

Conclusions

The present data have for the first time provided histologic evidence for periodontal regeneration of gingival recession defects following treatment with CAF and HA.

Clinical relevance

The use of HA in conjunction with CAF may represent a novel modality for treating gingival recession defects.

Healing of intrabony defects following regenerative surgery by means of single-flap approach in conjunction with either hyaluronic acid or an enamel matrix derivative: a 24-month randomized controlled clinical trial

Objectives

The aim of this randomized controlled clinical trial was to compare the clinical outcomes obtained in intrabony defects following regenerative periodontal surgery using the single-flap approach (SFA) in conjunction with either hyaluronic acid (HA) or enamel matrix derivative (EMD).

Materials and methods

Thirty-two intrabony defects in 32 healthy subjects were randomly assigned: HA (test group) or EMD (control group). Clinical attachment level (CAL), probing depth (PD), gingival recession (REC), and bleeding on probing (BOP) were recorded at baseline,12, 18, and 24 months after surgery.

Results

At 24 months, both treatments resulted in statistically significant clinical improvements evidenced by PD-reduction and CAL-gain (p<0.001). The mean CAL-gain was 2.19±1.11 mm in the test and 2.94±1.12 mm in the control sites (p=0.067). PD-reduction was statistically significantly higher for the control group (4.5±0.97 mm) than the test group (3.31±0.70 mm), (p=0.001). CAL-gain ≤ 3 mm was observed in 87.5% and in 62.5% of the test and control sites, respectively. Test sites showed slightly lower REC values than the control sites. No statistically significant differences were found for BOP between treatments.

Conclusions

The present findings indicate that both treatments led to statistically significant clinical improvements compared to baseline, although the application of EMD resulted in statistically significantly higher PD-reduction compared to the use of HA.

Clinical relevance

The use of HA in conjunction with a SFA resulted in significant PD-reduction and CAL-gain, pointing to the potential clinical relevance of this material in regenerative periodontal surgery.

Biological molecules in dental applications: hyaluronic acid as a companion biomaterial for diverse dental applications

Objectives

The application of hyaluronic acid (HA) in dental treatments is relatively new, and modified-HA products can be vastly different from each other. This study aims to provide a basis for bridging specific characteristics of HA with its potential applications in dental treatments, evaluating and comparing different types of HA products and for future research on HA applications in dentistry.

Data sources

Information from the existing literature on HA applications has been cited.

Study selection

Furthermore, this study is specifically oriented to provide oral health care providers with a scientific basis for HA use along with the clinical aspects of HA.

Conclusions

Outcomes from existing and future studies cannot be generalised for HA use in dental applications. Therefore, we have proposed a scheme to bridge HA specific characteristics to its applications in dental treatments and compare different HA products used for the same clinical application to identify the most suitable one.

Clinical significance

Highlighting the use of HA in dental treatments and providing a basis for developing new methods, protocols, and products specifically oriented for dentistry.

Role of hyaluronan in regulating self-renewal and osteogenic differentiation of mesenchymal stromal cells and pre-osteoblasts

Objectives

The aim of the study was to investigate the impact of two hyaluronan (HA) formulations on the osteogenic potential of osteoblast precursors.

Materials and methods

Proliferation rates of HA-treated mesenchymal stromal ST2 and pre-osteoblastic MC3T3-E1 cells were determined by 5-bromo-20-deoxyuridine (BrdU) assay. Expression of genes encoding osteogenic differentiation markers, critical growth, and stemness factors as well as activation of downstream signaling pathways in the HA-treated cells were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunoblot techniques.

Results

The investigated HAs strongly stimulated the growth of the osteoprogenitor lines and enhanced the expression of genes encoding bone matrix proteins. However, expression of late osteogenic differentiation markers was significantly inhibited, accompanied by decreased bone morphogenetic protein (BMP) signaling. The expression of genes encoding transforming growth factor-β1 (TGF-β1) and fibroblast growth factor-1 (FGF-1) as well as the phosphorylation of the downstream signaling molecules Smad2 and Erk1/2 were enhanced upon HA treatment. We observed significant upregulation of the transcription factor Sox2 and its direct transcription targets and critical stemness genes, Yap1 and Bmi1, in HA-treated cells. Moreover, prominent targets of the canonical Wnt signaling pathway showed reduced expression, whereas inhibitors of the pathway were considerably upregulated. We detected decrease of active β-catenin levels in HA-treated cells due to β-catenin being phosphorylated and, thus, targeted for degradation.

Conclusions

HA strongly induces the growth of osteoprogenitors and maintains their stemness, thus potentially regulating the balance between self-renewal and differentiation during bone regeneration following reconstructive oral surgeries.

Clinical relevance

Addition of HA to deficient bone or bony defects during implant or reconstructive periodontal surgeries may be a viable approach for expanding adult stem cells without losing their replicative and differentiation capabilities.

Electronic supplementary material

The online version of this article (10.1007/s00784-020-03259-8) contains supplementary material, which is available to authorized users.

Activity of two hyaluronan preparations on primary human oral fibroblasts

Background and Objective

The potential benefit of using hyaluronan (HA) in reconstructive periodontal surgery is still a matter of debate. The aim of the present study was to evaluate the effects of two HA formulations on human oral fibroblasts involved in soft tissue wound healing/regeneration.

Material and Methods

Metabolic, proliferative and migratory abilities of primary human palatal and gingival fibroblasts were examined upon HA treatment. To uncover the mechanisms whereby HA influences cellular behavior, wound healing‐related gene expression and activation of signaling kinases were analyzed by qRT‐PCR and immunoblotting, respectively.

Results

The investigated HA formulations maintained the viability of oral fibroblasts and increased their proliferative and migratory abilities. They enhanced expression of genes encoding type III collagen and transforming growth factor‐β3, characteristic of scarless wound healing. The HAs upregulated the expression of genes encoding pro‐proliferative, pro‐migratory, and pro‐inflammatory factors, with only a moderate effect on the latter in gingival fibroblasts. In palatal but not gingival fibroblasts, an indirect effect of HA on the expression of matrix metalloproteinases 2 and 3 was detected, potentially exerted through induction of pro‐inflammatory cytokines. Finally, our data pointed on Akt, Erk1/2 and p38 as the signaling molecules whereby the HAs exert their effects on oral fibroblasts.

Conclusion

Both investigated HA formulations are biocompatible and enhance the proliferative, migratory and wound healing properties of cell types involved in soft tissue wound healing following regenerative periodontal surgery. Our data further suggest that in gingival tissues, the HAs are not likely to impair the healing process by prolonging inflammation or causing excessive MMP expression at the repair site.