Hyaluronan in non-surgical and surgical periodontal therapy: a systematic review

Efficacy of adjunctive local periodontal treatment for type 2 diabetes mellitus patients with periodontitis: A systematic review and network meta-analysis

OBJECTIVES

To investigate the effectiveness of different adjunctive local treatments combined with non-surgical periodontal therapy (NSPT) to reduce pocket depth (PD), gain clinical attachment level (CAL), and/or reduce glycated hemoglobin (HbA1c) in individuals with both type 2 diabetes mellitus (T2DM) and periodontitis in a systematic review and network meta-analysis.

DATA SOURCES

Publications were searched in Cochrane databases, EMBASE, Google Scholar, MEDLINE, PubMed, opengrey.eu, and www.

CLINICALTRIALS

gov up to May 29, 2024 with no language restriction.

STUDY SELECTION

Only randomized controlled trials (RCTs) were included. Network meta-analysis utilized frequentist models.

DATA

The network meta-analysis of 30 RCTs involving 1224 patients revealed that, in short-term (2-3 months) and medium-term (4-6 months), adjunctive local treatment involving statins or metformin significantly outperformed scaling and root planning (SRP) with/without additional interventions such as photodynamic and laser therapies (PDT/LT), phytotherapy, doxycycline, bisphosphonates, antibiotics, antiseptics, or placebo for reducing PD and/or gaining CAL. In the long-term (>6 months), statins yielded the most significant additional PD reduction and CAL gain, followed by antibiotics, compared to SRP with antiseptics or placebo. Only PDT/LT demonstrated significantly greater HbA1c reduction in the short term compared to SRP with/without statins, antiseptics, or placebo.

CONCLUSION

This study moderately supports that adding metformin or statins locally to NSPT may enhance PD reduction and CAL gain compared to SRP with/without placebo.

CLINICAL SIGNIFICANCE

Clinicians are guided to optimize adjunctive therapies, enhancing the health of patients with type 2 diabetes and periodontitis. A strategic approach is proposed to tackle systemic and oral health challenges simultaneously.

In-vitro effects of different hyaluronic acids on periodontal biofilm-immune cell interaction

Introduction

Recent studies have demonstrated a positive role of hyaluronic acid (HA) on periodontal clinical outcomes. This in-vitro study aimed to investigate the impact of four different HAs on interactions between periodontal biofilm and immune cells.

Methods

The four HAs included: high-molecular-weight HA (HHA, non-cross-linked), low-molecular-weight HA (LHA), oligomers HA (OHA), and cross-linked high-molecular-weight HA (CHA). Serial experiments were conducted to verify the influence of HAs on: (i) 12-species periodontal biofilm (formation and pre-existing); (ii) expression of inflammatory cytokines and HA receptors in monocytic (MONO-MAC-6) cells and periodontal ligament fibroblasts (PDLF) with or without exposure to periodontal biofilms; (iii) generation of reactive oxygen species (ROS) in MONO-MAC-6 cells and PDLF with presence of biofilm and HA.

Results

The results indicated that HHA and CHA reduced the bacterial counts in a newly formed (4-h) biofilm and in a pre-existing five-day-old biofilm. Without biofilm challenge, OHA triggered inflammatory reaction by increasing IL-1β and IL-10 levels in MONO-MAC cells and IL-8 in PDLF in a time-dependent manner, whereas CHA suppressed this response by inhibiting the expression of IL-10 in MONO-MAC cells and IL-8 in PDLF. Under biofilm challenge, HA decreased the expression of IL-1β (most decreasing HHA) and increased IL-10 levels in MONO-MAC-6 cells in a molecular weight dependent manner (most increasing CHA). The interaction between HA and both cells may occur via ICAM-1 receptor. Biofilm stimulus increased ROS levels in MONO-MAC-6 cells and PDLF, but only HHA slightly suppressed the high generation of ROS induced by biofilm stimulation in both cells.

Conclusion

Overall, these results indicate that OHA induces inflammation, while HHA and CHA exhibit anti-biofilm, primarily anti-inflammatory, and antioxidant properties in the periodontal environment.

Early periodontal wound healing after chlorhexidine rinsing: a randomized clinical trial

OBJECTIVES

This single-center randomized, parallel design, clinical trial with a 2-week follow-up involved patients affected by periodontitis undergoing periodontal surgery. The aim was to evaluate periodontal surgical wound healing with the use of chlorhexidine-based mouth rinses versus an untreated control group.

MATERIALS AND METHODS

Periodontal surgery was performed following a standardized protocol. Patients were randomly prescribed i) chlorhexidine (CHX) + anti-discoloration system (ADS) + hyaluronic acid (HA), ii) CHX + ADS or iii) no treatment (control group). Plaque score, gingival inflammation, and Early Healing Index (EHI), assessing the degree of wound closure and the presence of fibrin and necrosis, were evaluated at 3, 7 and 14 days after surgery.

RESULTS

In total, 33 patients were enrolled. Patients were comparable at baseline for all measured clinical parameters. At 3-days wound healing was significantly improved in all patients treated with CHX + ADS-based mouth rinses with a lower EHI score at the interdental papillae compared with control group (p < 0.01). CHX + ADS + HA group presented improved healing across all time points in terms of EHI, plaque containment, and gingival inflammation when compared to control group (p < 0.01).

CONCLUSIONS

The usage of CHX-ADS following periodontal surgery improved early wound healing, reduced plaque accumulation and gingival inflammation. During the early post-operative period the adjunct of HA further improved soft tissue closure.

CLINICAL RELEVANCE

This study aims at evaluating the response of gingival tissues to mouth rinsing with chlorhexidine and anti-discoloration system (CHX + ADS) or CHX + ADS + hyaluronic acid (CHX + ADS + HA) versus no rinse in terms of healing of the periodontal surgical wound. CHX + ADS mouth rinses enhanced early soft tissue closure after periodontal surgery and contributed to the reduction in plaque accumulation and gingival inflammation. The adjunct of HA may be beneficial especially in the early post-operative period. CHX + ADS administration following periodontal surgery may improve soft tissue healing in the first two post-operative weeks.

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.

From Basic Science to Clinical Practice: A Review of Current Periodontal/Mucogingival Regenerative Biomaterials

Periodontitis is a dysbiosis-driven inflammatory disease affecting the tooth-supporting tissues, characterized by their progressive resorption, which can ultimately lead to tooth loss. A step-wise therapeutic approach is employed for periodontitis. After an initial behavioral and non-surgical phase, intra-bony or furcation defects may be amenable to regenerative procedures. This review discusses the regenerative technologies employed for periodontal regeneration, highlighting the current limitations and future research areas. The search, performed on the MEDLINE database, has identified the available biomaterials, including biologicals (autologous platelet concentrates, hydrogels), bone grafts (pure or putty), and membranes. Biologicals and bone grafts have been critically analyzed in terms of composition, mechanism of action, and clinical applications. Although a certain degree of periodontal regeneration is predictable in intra-bony and class II furcation defects, complete defect closure is hardly achieved. Moreover, treating class III furcation defects remains challenging. The key properties required for functional regeneration are discussed, and none of the commercially available biomaterials possess all the ideal characteristics. Therefore, research is needed to promote the advancement of more effective and targeted regenerative therapies for periodontitis. Lastly, improving the design and reporting of clinical studies is suggested by strictly adhering to the Consolidated Standards of Reporting Trials (CONSORT) 2010 statement.

Repeated local delivery of hyaluronic acid gel as adjunctive treatment of residual pockets in periodontitis patients undergoing supportive periodontal care. A randomized controlled clinical trial

OBJECTIVES

To assess the effect of hyaluronic acid (HyA) application as adjunct to re-instrumentation of residual pockets in patients undergoing regular supportive periodontal care (SPC).

METHODS

Chronic periodontitis patients (stage III and IV, grade B and C) with 4 interproximal residual pockets were randomly assigned to the test (HyA gel) or control (saline) group. After subgingival instrumentation, test or control substance was applied subgingivally, then daily supragingivally for 3 months, and if required a second time after subgingival re-instrumentation after 3 months. Clinical and patient reported outcome parameters were recorded every 3 months for 12 months. Pocket closure [probing pocket depth (PPD) ≤ 4mm with absence of bleeding on probing (BoP) at PPD = 4mm] was the main outcome parameter.

RESULTS

Fifty-six patients (221 experimental sites) were analysed. Pocket closure was achieved in 56.8 and 46.6% of the experimental sites in the test and control group, respectively (p > 0.05), while median PPD and PPD distribution (< 5mm/5mm/ > 5mm) differed significantly between groups in favour of the test group, at 12 months. Further, significantly fewer sites in the HyA group required re-instrumentation at 3 months, and sites in the HyA group showed a tendency for lower odds to remain diseased compared to the control group (OR 0.48, 95%CI 0.22-1.06). The odds for a site to remain diseased after 12 months increased significantly in the presence of plaque (OR 7.94, 95%CI 4.12-15.28), but in general, decreased significantly over time (OR 0.48, 95%CI 0.28-0.81).

CONCLUSION

Re-instrumentation of residual pockets in SPC patients, per se, leads to a significant increase in pocket closure over time; this was impeded by poor plaque control. Repeated local application of HyA results in fewer sites requiring re-instrumentation and might slightly improve the rate of pocket closure. (clinicaltrials.gov registration nr. NCT04792541).

CLINICAL RELEVANCE

HyA gel is easy to apply, well accepted by patients, and may have some positive effect in terms of fewer sites requiring re-instrumentation at 3 months and higher pocket closure rate at 12 months.

Control of tissue homeostasis by the extracellular matrix: Synthetic heparan sulfate as a promising therapeutic for periodontal health and bone regeneration

Proteoglycans are core proteins associated with carbohydrate/sugar moieties that are highly variable in disaccharide composition, which dictates their function. These carbohydrates are named glycosaminoglycans, and they can be attached to proteoglycans or found free in tissues or on cell surfaces. Glycosaminoglycans such as hyaluronan, chondroitin sulfate, dermatan sulfate, keratan sulfate, and heparin/heparan sulfate have multiple functions including involvement in inflammation, immunity and connective tissue structure, and integrity. Heparan sulfate is a highly sulfated polysaccharide that is abundant in the periodontium including alveolar bone. Recent evidence supports the contention that heparan sulfate is an important player in modulating interactions between damage associated molecular patterns and inflammatory receptors expressed by various cell types. The structure of heparan sulfate is reported to dictate its function, thus, the utilization of a homogenous and structurally defined heparan sulfate polysaccharide for modulation of cell function offers therapeutic potential. Recently, a chemoenzymatic approach was developed to allow production of many structurally defined heparan sulfate carbohydrates. These oligosaccharides have been studied in various pathological inflammatory conditions to better understand their function and their potential application in promoting tissue homeostasis. We have observed that specific size and sulfation patterns can modulate inflammation and promote tissue maintenance including an anabolic effect in alveolar bone. Thus, new evidence provides a strong impetus to explore heparan sulfate as a potential novel therapeutic agent to treat periodontitis, support alveolar bone maintenance, and promote bone formation.

Hyaluronic acid in tooth extraction: a systematic review and meta-analysis of preclinical and clinical trials

OBJECTIVES

To assess whether in animals or patients with ≥ 1 tooth extracted, hyaluronic acid (HyA) application results in superior healing and/or improved complication management compared to any other treatment or no treatment.

MATERIALS AND METHODS

Three databases were searched until April 2022. The most relevant eligibility criteria were (1) local application of HyA as adjunct to tooth extraction or as treatment of alveolar osteitis, and (2) reporting of clinical, radiographic, histological, or patient-reported data. New bone formation and/or quality were considered main outcome parameters in preclinical studies, while pain, swelling, and trismus were defined as main outcome parameters in clinical studies.

RESULTS

Five preclinical and 22 clinical studies (1062 patients at final evaluation) were included. In preclinical trials, HyA was applied into the extraction socket. Although a positive effect of HyA was seen in all individual studies on bone formation, this effect was not confirmed by meta-analysis. In clinical studies, HyA was applied into the extraction socket or used as spray or mouthwash. HyA application after non-surgical extraction of normally erupted teeth may have a positive effect on soft tissue healing. Based on meta-analyses, HyA application after surgical removal of lower third molars (LM3) resulted in significant reduction in pain perception 7 days postoperatively compared to either no additional wound manipulation or the application of a placebo/carrier. Early post-operative pain, trismus, and extent of swelling were unaffected.

CONCLUSIONS

HyA application may have a positive effect in pain reduction after LM3 removal, but not after extraction of normally erupted teeth.

CLINICAL RELEVANCE

HyA application may have a positive effect in pain reduction after surgical LM3 removal, but it does not seem to have any impact on other complications or after extraction of normally erupted teeth. Furthermore, it seems not to reduce post-extraction alveolar ridge modeling, even though preclinical studies show enhanced bone formation.

Hyaluronic Acid: Exploring Its Versatile Applications in Dentistry

Hyaluronic acid (HA) a polysaccharide present in many areas of the body like the synovium of synovial joints, and connective tissues which have high regenerative and biocompatible properties has been an area of interest since recent times in dentistry. Several research papers and review articles were studied in the Pubmed database to formulate this review article. The main aim of this article is to demonstrate various applications of HA in different branches of dentistry. The PubMed database was searched for keywords "Hyaluronic acid AND periodontics," "Hyaluronic acid AND oral and maxillofacial surgery," "Hyaluronic acid AND oral medicine," "Hyaluronic acid AND orthodontics," "Hyaluronic acid AND endodontics," and "Hyaluronic acid AND aesthetic dentistry" which resulted in six, 296, 83, 86, 40, and 49 articles, respectively. The most relevant and informative articles were selected and studied for this review article. This review article will also help people to gain knowledge about the future aspects of the use of HA in dentistry and also motivate clinicians and new-generation dentists to inculcate the HA's use in their respective practice in dentistry.

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.

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.

Photothermal nanofibrillar membrane based on hyaluronic acid and graphene oxide to treat Staphylococcus aureus and Pseudomonas aeruginosa infected wounds

Here we reported the fabrication of an electrospun membrane based on a hyaluronic acid derivative (HA-EDA) to be used as a bandage for the potential treatment of chronic wounds. The membrane, loaded with graphene oxide (GO) and ciprofloxacin, showed photothermal properties and light-triggered drug release when irradiated with a near-infrared (NIR) laser beam. Free amino groups of HA-EDA derivative allowed autocrosslinking of the electrospun membrane; thus, a substantial enhancement in the hydrolytic resistance of the patch was obtained. In vitro antibacterial activity studies performed on Staphylococcus aureus and Pseudomonas aeruginosa revealed that such electrospun membranes, due to the synergistic effect of the antibiotic and NIR-mediated hyperthermia, reduced the viability of both pathogens. Specific in vitro experiment demonstrated also that is possible to disrupt, through laser irradiation, the biofilms formed onto the membrane.

Evaluation of the effectiveness of a novel mouth rinse containing hyaluronic acid and hydrogen peroxide on gingivitis: A randomized pilot controlled trial

Objective

To evaluate and compare the effectiveness of a mouth rinse with hydrogen peroxide (H₂O₂) and hyaluronic acid (HA) versus a placebo mouth rinse on gingivitis.

Material and methods

This was a 21‐day, double blind, randomized, two‐arm parallel allocation placebo‐controlled trial of 50 study participants with a diagnosis of plaque‐induced gingivitis. Patients were randomly allocated to the test group or the placebo group and were assessed at three time points over the course of the study by the same operator, at baseline (T0), 7 days (T1), and 21 days follow‐up (T2). Primary outcomes of the trial were improvement in gingivitis and plaque accumulation.

Results

In both groups there was a decrease in gingival and plaque indices but the combination of the two actives (H₂O₂/HA) proved to be more effective against gingivitis (p = 0.001). Regarding plaque index, the differences between the test product and placebo were not statistically significant (p = 0.084). Besides, the new mouthwash was considered palatable, no adverse events were registered over the 21‐day period.

Conclusions

The H₂O₂ + HA product was more effective in reducing gingivitis when compared to a placebo while no differences were observed for plaque accumulation.

A thermosensitive gel with an active hyaluronic acid ingredient that contains an octenidine preservation system as an adjunct to scaling and root planning: a randomized prospective clinical study

OBJECTIVES

To evaluate the adjunctive effect of a thermosensitive gel formulation that contains 0.8% oligo hyaluronic acid (HA) combined with a preservation system of octenidine HCl 0.625% and phenoxyethanol to scaling and root planing (SRP) as compared with SRP alone in the treatment of residual pockets of patients with stage 3 periodontitis.

MATERIALS AND METHODS

Thirty-four patients (21 males and 13 females) aged 29-78 years (51.3 ± 13.1) with stage 3 periodontitis were recruited to participate in the present split-mouth study. None of the patients has been previously treated for periodontitis. Plaque index (PI), probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were evaluated at baseline and at 3 and 6 months post treatment. Full-mouth SRP was performed in all residual pockets ≥ 5 mm. Treatment was performed by means of ultrasonic and hand instruments and lasted 45-60 min. The gel was applied subgingivally in the test sites immediately after SRP (baseline) and 1 month later. The paired t-test for two means was applied to test the statistical significance of the change from baseline within each arm and determine the difference between groups. The level of significance was set at 0.05 for all tests.

RESULTS

Mean PD reductions between baseline and 3 and 6 months were 1.98 mm and 2.79 mm for the test and 1.22 mm and 1.50 mm for the control group, respectively. Comparisons between the test and control groups revealed that SRP + gel yielded statistically significantly higher PD reductions compared to SRP alone (p < 0.0001). Compared to baseline, CAL and BOP values improved statistically significantly in both groups, although the test group presented statistically significantly higher CAL gains and BOP reductions than the control group (P < 0.0001).

CONCLUSION

In residual pockets of stage 3 periodontitis patients, the local application of a thermosensitive gel with an active HA ingredient and a preservation system of octenidine HCl 0.625% in conjunction with SRP may additionally improve the clinical outcomes obtained with SRP alone.

CLINICAL RELEVANCE

A novel HA and octenidine containing thermosensitive gel effectively improved the clinical parameters in stage 3 periodontitis patients over a 6-month period.

Treatment of Intrabony Defects with a Combination of Hyaluronic Acid and Deproteinized Porcine Bone Mineral

Background: this study evaluates the clinical outcomes of a novel approach in treating deep intrabony defects utilizing papilla preservation techniques with a combination of hyaluronic acid (HA) and deproteinized porcine bone mineral. Methods: 23 patients with 27 intrabony defects were treated with a combination of HA and deproteinized porcine bone mineral. Clinical attachment level (CAL), pocket probing depth (PPD), gingival recession (REC) were recorded at baseline and 6 months after the surgery. Results: At 6 months, there was a significant CAL gain of 3.65 ± 1.67 mm (p < 0.001) with a PPD reduction of 4.54 ± 1.65 mm (p < 0.001), which was associated with an increase in gingival recession (0.89 ± 0.59 mm, p < 0.001). The percentage of pocket resolution based on a PPD ≤4 mm was 92.6% and the failure rate based on a PPD of 5 mm was 7.4%. Conclusions: the present findings indicate that applying a combined HA and xenograft approach in deep intrabony defects provides clinically relevant CAL gains and PPD reductions compared to baseline values and is a valid new approach in treating intrabony defects.

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.

Combination of enamel matrix derivative and hyaluronic acid inhibits lipopolysaccharide-induced inflammatory response on human epithelial and bone cells

Objectives

The aim of this study was to evaluate the in vitro effect of enamel matrix derivative (EMD) and hyaluronic acid (HA) and their synergistic combination on lipopolysaccharides (LPS)-induced inflammation in human keratinocytes and osteoblasts.

Material and methods

Cells were challenged with LPS (1 μg/ml) and cultured in the following treatment groups with EMD (30 mg/ml) and HA (30 mg/ml): LPS, EMD, HA, EMD + HA, EMD + LPS, HA + LPS, and EMD + HA + LPS. Cell viability, inflammatory cytokine expression, and cell migration were determined using colorimetric assay, quantitative real-time polymerase chain reaction (qPCR), and scratch wound healing assay, respectively.

Results

Cell viability was decreased when exposed to LPS compared to the controls. Overall, LPS treatment expressed upregulation on inflammatory cytokine tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). EMD and HA reduced up to 3.0-fold the cytokine expression caused by LPS (p < 0.05). EMD and HA statistically induced higher migration in osteoblasts and keratinocytes, respectively. Migration was impaired by LPS, whereas it significantly increased after addition of EMD and HA.

Conclusions

EMD and HA are advantageous biomaterials that individually generate strong directional migratory keratinocyte and osteoblast response. Their combination also enhances cell viability, and anti-inflammatory and migratory abilities to promote healing specially under LPS inflammatory stimulus. Future in vivo and animal research is necessary to further characterize the effect of EMD and HA on periodontal regeneration.

Clinical relevance

The use of EMD in conjunction with HA resulted in a reduction of inflammation and improvement of tissue healing at wound sites. Both biomaterials combined may potentially improve the effectiveness of bone regeneration in periodontal bone defects, pointing to the potential clinical relevance of both materials in regenerative periodontal surgery.

Hyaluronic Acid Is an Effective Dermal Filler for Lip Augmentation: A Meta-Analysis

Introduction: The lips and the mouth play an indispensable role in vocalization, mastication and face aesthetics. Various noxious factors may alter and destruct the original structure, and appearance of the lips and the anatomical area surrounding the mouth. The application of hyaluronic acid (HA) may serve as a safe method for lip regeneration. Although a number of studies exist for HA effectiveness and safety, its beneficial effect is not well-established. Aim: The present meta-analysis and systematic review was performed to investigate the effectiveness of HA on lip augmentation. We also investigated the types and nature of adverse effects (AEs) of HA application. Methods: We reported our meta-analysis in accordance with the PRISMA Statement. PROSPERO protocol registration: CRD42018102899. We performed the systematic literature search in CENTRAL, Embase, and MEDLINE. Randomized controlled trials, cohort studies, case series and case reports were included. The untransformed proportion (random-effects, DerSimonian-Laird method) of responder rate to HA injection was calculated. For treatment related AEs descriptive statistics were used. Results: The systematic literature search yielded 32 eligible records for descriptive statistics and 10 records for quantitative synthesis. The results indicated that the overall estimate of responders (percentage of subjects with increased lip fullness by one point or higher) was 91% (ES = 0.91, 95% CI:0.85-0.96) 2 months after injection. The rate of responders was 74% (ES = 0.74, 95% CI:0.66-0.82) and 46% (ES = 0.46, 95% CI:0.28-0.65) after 6 and 12 months, respectively. We included 1,496 participants for estimating the event rates of AEs. The most frequent treatment-related AEs were tenderness (88.8%), injection site swelling (74.3%) and bruising (39.5%). Rare AEs included foreign body granulomas (0.6%), herpes labialis (0.6%) and angioedema (0.3%). Conclusion: Our meta-analysis revealed that lip augmentation with injectable HA is an efficient method for increasing lip fullness for at least up to 6 months after augmentation. Moreover, we found that most AEs of HA treatment were mild or moderate, but a small number of serious adverse effects were also found. In conclusion, further well-designed RCTs are still needed to make the presently available evidence stronger.

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.

Characterization of a hyaluronic acid-based hydrogel containing an extracellular oxygen carrier (M101) for periodontitis treatment: An in vitro study

Periodontitis is an inflammatory disease associated with anaerobic bacteria leading to the destruction of tooth-supporting tissues. Porphyromonas gingivalis is a keystone anaerobic pathogen involved in the development of severe lesions. Periodontal treatment aims to suppress subgingival biofilms and to restore tissue homeostasis. However, hypoxia impairs wound healing and promotes bacterial growth within periodontal pocket. This study aimed to evaluate the potential of local oxygen delivery through the local application of a hydrogel containing Arenicola marina's hemoglobin (M101). To this end, a hydrogel (xanthan (2%), hyaluronic acid (1%)) containing M101 (1-2 g/L) (Xn(2%)-HA(1%)-M101) was prepared and characterized. Rheological tests revealed the occurrence of high deformation without the loss of elastic properties. Dialysis experiment revealed that incorporation of M101 within the gel did not modify its oxygen transportation properties. Samples of release media of the gels (1 g/L (10%) and 2 g/L (10%) M101) decreased significantly the growth of P. gingivalis after 24 h validating its antibacterial effect. Metabolic activity measurement confirmed the cytocompatibility of Xn(2%)-HA(1%)-M101. This study suggests the therapeutic interest of Xn(2%)-HA(1%)-M101 gel to optimize treatment of periodontitis with a non-invasive approach.

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.

Comparative Evaluation of Two Hyaluronic Acid Gel Products for the Treatment of Interdental Papillary Defects

Objectives

The aim was to investigate the efficacy of single injections of two different hyaluronic acid products, Flex Barrier and Revident, in reducing the size of black triangles to treat Nordland-Tarnow Class I and II recessions.

Materials and Methods

Forty adult patients were recruited with at least two upper and two lower interdental papilla defects in the front region between canine teeth. According to the Nordland-Tarnow classification of papillary defects, both Class I and Class II recessions were included in the investigation. Patients were randomly assigned to experimental groups to receive single injections of two different hyaluronic acid products, either Flex Barrier or Revident. The untreated sites served as controls. Photographs were taken before and immediately after the treatment, and again after one week and one month. To determine the size of the black triangles, Image J software was used. For statistical analysis, a mixed-design ANOVA was applied.

Results

Both Flex Barrier and Revident significantly decreased the size of the treated defects immediately after the treatment and also one week later (p<0.001). The beneficial effect of Revident lasted longer than Flex Barrier as it remained significant even after one month in Revident-treated patients, however, not in the Flex Barrier-treated group. Furthermore, Nordland-Tarnow Class I lesions generally showed a greater improvement than Class II lesions.

Conclusion

In this proof-of-concept, randomized clinical trial we have demonstrated the clinical applicability of both Flex Barrier and Revident, although Revident gave longer-lasting improvements than Flex Barrier. Further trials are needed to optimize multiple-application protocols for treating gingival black triangles.

Evaluation of biochemical and clinical effects of hyaluronic acid on non-surgical periodontal treatment: a randomized controlled trial

BACKGROUND

Recent studies reported that hyaluronic acid (HA) has anti-inflammatory, anti-edematous, and anti-bacterial activities in dentistry, particularly in gingival disorders caused by subgingival plaque microorganisms.

AIMS

This study aimed to evaluate the early term effects of HA as an adjunct to scaling and root planing (SRP) on clinical parameters, periodontal inflamed surface area (PISA), and adenosine deaminase (ADA), catalase (CAT), and glutathione (GSH) levels in gingival crevicular fluid (GCF) in periodontitis.

METHODS

A total of 24 periodontitis patients per group were included in this randomized-controlled study. The study population was divided into four groups: in Group 1: SRP+ saline; in Group 2: SRP + HA gel; in Group 3: SRP+ HA mouth rinse; and in Group 4: SRP + HA mouth rinse + HA gingival gel were applied. At baseline and week 4, clinical parameters and PISA were calculated. Also, biochemicals' (ADA, CAT, and GSH) levels were determined by spectrophotometric analysis.

RESULTS

There was a statistically significant improvement in clinical parameters and PISA in all four groups in control sessions (p < 0.05). There was a significant decrease in ADA in GCF and significant increases in CAT and GSH levels after SRP (p < 0.05) in all four groups. The groups that were administered only gel (2nd and 4th) were different from other groups in terms of ADA, CAT, and GSH levels at 1st week (p < 0.05).

CONCLUSION

HA application as an adjunct to SRP did not affect the clinical results, although, in the control sessions following the application, the results were favorable for the biochemical data in gel-applied groups.

TRIAL REGISTRATION

ClinicalTrials.gov.tr (NCT03754010).

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.

A randomized double-blind clinical trial to evaluate the efficacy of chlorhexidine, antioxidant, and hyaluronic acid mouthwashes in the management of biofilm-induced gingivitis

OBJECTIVES

To investigate the antiplaque and antigingivitis efficacy in addition to evaluating side effects and subjects' perceptions of three commercially available mouthwashes.

METHODS

This study was a double-blind, parallel, and short-term trial. A total of 75 dental students with biofilm-induced gingivitis were included in the final analysis of the current study. Clinical parameters (plaque index and bleeding on probing) and the staining effect were measured at baseline and after 7 days. In addition, a VAS-based assessment questionnaire was completed by the participants.

RESULTS

All interventions significantly reduced plaque scores, but chlorhexidine (CHX) had a significantly higher effect than the hyaluronic acid (HA) and antioxidant mouthwashes. However, all mouthwashes significantly reduced the total bleeding scores to <10% in 53% of the patients, compared to the baseline record. Additionally, teeth underwent shade changes in association with all interventions by the end of the study. Analysis of feedback about the mouthwashes showed that the participants seemed to prefer the HA mouthwash over the other mouthwashes.

CONCLUSIONS

CHX remains the most effective antiplaque mouthwash although HA and antioxidants are as effective as CHX in reducing bleeding. In addition, based on its better acceptance by the participants, HA is potentially a good alternative to CHX.

Single application of 0.8% hyaluronic acid as a coadjuvant of nonsurgical treatment in nonsmoking patients with periodontitis: A split-mouth, randomized, controlled pilot clinical trial

Background:

Topical coadjuvants might be indicated to increase the results of nonsurgical periodontal treatment and overcome some of its limitations. The aim of this study was to evaluate the clinical benefits of a single topical application of 0.8% hyaluronic acid (HA) as a coadjuvant to scaling and root planing (SRP) in periodontal patients.

Materials and Methods:

Sixteen patients diagnosed with periodontitis were recruited to participate in this split-mouth randomized controlled trial. At baseline, oral hygiene instructions, prophylaxis, and SRP were performed in both sides; additionally, a subgingival application of HA at 0.8% was made in the test side. Several clinical parameters were assessed at baseline, 6, and 12 weeks later: full mouth plaque score, gingival score, bleeding on probing (BoP), probing depth (PD), and clinical attachment level (CAL).

Results:

At the end of 12 weeks, there was a overall improvement in all periodontal parameters in both sides (P < 0.05). Test sides showed less BoP when compared to the control sides (9.4 ± 4.0 vs. 14.9 ± 8.9, P < 0.05). Other periodontal parameters such as PD and CAL showed a slight improvement in comparison with the control sides, but the difference was not statistically significant (P > 0.05).

Conclusion:

Results from this study indicate that a single subgingival application of 0.8% HA seems to reduce gingival inflammation and improve clinical parameters, particularly BoP. Further studies are needed to evaluate the effect of repeated application of HA and long-term results.

Effect of topically applied hyaluronic acid on pain and palatal epithelial wound healing: An examiner-masked, randomized, controlled clinical trial

BACKGROUND

This study aims to evaluate the effects of two different concentrations of topical hyaluronic acid (HA) on postoperative patient discomfort and wound healing of palatal donor sites after free gingival graft (FGG) surgery.

METHODS

Thirty-six patients requiring FGG were randomly assigned into three groups in an examiner-masked, randomized, controlled clinical trial. After harvesting palatal grafts, 0.2% and 0.8% HA gels were used in test groups 1 and 2, respectively. Gels were applied on donor sites and protected with periodontal dressing in the test groups, whereas the wound was covered only with periodontal dressing in the control group. On days 3, 7, 14, and 21, pain and burning sensation were recorded using a visual analog scale (VAS) as well as other parameters such as complete epithelization (CE) and color match on days 3, 7, 14, 21, and 42.

RESULTS

Test groups experienced less pain than the control group on days 3 and 7 (P <0.001 and P <0.001, respectively). Mean VAS score for burning sensation was higher in the control group on day 3 compared with test groups 1 and 2 (P = 0.03 and P = 0.02, respectively). CE in all patients was achieved on day 21 in both test groups, whereas it was achieved on day 42 in the control group. The test groups showed higher color match scores than the control group on days 21 (P <0.001 and P <0.001, respectively) and 42 (P = 0.004 and P = 0.002, respectively).

CONCLUSION

Topical application of HA exhibits positive impact on postoperative pain and burning sensation, and accelerates palatal wound healing in terms of epithelization and color match.

Hyaluronic acid as adjunctive to non-surgical and surgical periodontal therapy: a systematic review and meta-analysis

OBJECTIVES

To evaluate the potential added benefit of the topical application of hyaluronic acid (HA) on the clinical outcomes following non-surgical or surgical periodontal therapy.

MATERIALS AND METHODS

A systematic search was performed in Medline, Embase, Cochrane, Web of Science, Scopus and Grey literature databases. The literature search was preformed according to PRISMA guidelines. The Cochrane risk of bias tool was used in order to assess the methodology of the included trials. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) between the treatment and controls were estimated using the random-effect model for amount of bleeding on probing (BOP), probing depth (PD) reduction and clinical attachment level (CAL) gain. In order to minimize the bias and to perform meta-analysis, only randomized clinical studies (RCTs) were selected.

RESULTS

Thirteen RCTs were included: 11 on non-surgical periodontal treatment and two on surgical periodontal treatment. Overall analysis of PD reduction, CAL gain and BOP reduction in non-surgical therapy with adjunctive HA presented WMD of - 0.36 mm (95% CI - 0.54 to - 0.19 mm; p < 0.0001), 0.73 mm (95% CI 0.28 to 1.17 mm; p < 0.0001) and - 15% (95% CI - 22 to - 8%; p < 0.001) respectively, favouring the application of HA. The overall analysis on PD and CAL gain in surgical therapy with adjunctive HA presented WMD of - 0.89 mm (95% CI - 1.42 to - 0.36 mm; p < 0.0001) for PD reduction and 0.85 mm (95% CI 0.08 to 1.62 mm; p < 0.0001) for CAL gain after 6-24 months favouring the treatment with HA. However, comparison presented considerable heterogeneity between the non-surgical studies and a high risk of bias in general.

CONCLUSIONS

Within their limits, the present data indicate that the topical application of HA may lead to additional clinical benefits when used as an adjunctive to non-surgical and surgical periodontal therapy. However, due to the high risk of bias and heterogeneity, there is a need for further well-designed RCTs to evaluate this material in various clinical scenarios.

CLINICAL RELEVANCE

The adjunctive use of HA may improve the clinical outcomes when used in conjunction with non-surgical and surgical periodontal therapy.

Hyaluronic Acid: The Reason for Its Variety of Physiological and Biochemical Functional Properties

Introduction:

Many physicians may be unfamiliar with the importance of hyaluronic acid (HA) and its physiological and biochemical functions at cellular level. Despite the vast number of published studies using HA in medical treatments, it is still difficult for the reader to clearly distinguish the different types of HA employed in different medical applications. In addition, published studies do not mention the exact type of HA used or its biochemical properties. Usually, a study mentions only its molecular weight and concentration, which are insufficient to know its exact designed properties or to make a comparison with other types of HA.

Methodology:

This article is intended to summarise the information about native and modified HAs with a focus on explaining their different physiological and biochemical functions in the human body, their different commercially available types, and how they affect the associated medical applications. The goal is to provide a basis to researchers and physicians for distinguishing different types of HA and their properties in order to enhance physicians’ clinical practice in terms of application of different types of HA to treatments and to help the international research community to change the reporting of HA characteristics in published papers. This is necessary to enhance future acquisition of data, with the ability to create an HA data bank for further research and as a reference for different HA types and their medical applications.

Conclusion:

These developments should enhance the scientific and clinical knowledge about HA. Furthermore, the overall approach in this paper can be applied to other similar substances.

Hyaluronan-CD44 interactions mediate contractility and migration in periodontal ligament cells

The role of hyaluronan (HA) in periodontal healing has been speculated via its interaction with the CD44 receptor. While HA-CD44 interactions have previously been implicated in numerous cell types; effect and mechanism of exogenous HA on periodontal ligament (PDL) cells is less clear. Herein, we examine the effect of exogenous HA on contractility and migration in human and murine PDL cells using arrays of microposts and time-lapse microscopy. Our findings observed HA-treated human PDL cells as more contractile and less migratory than untreated cells. Moreover, the effect of HA on contractility and focal adhesion area was abrogated when PDL cells were treated with Y27632, an inhibitor of rho-dependent kinase, but not when these cells were treated with ML-7, an inhibitor of myosin light chain kinase. Our results provide insight into the mechanobiology of PDL cells, which may contribute towards the development of therapeutic strategies for periodontal healing and tissue regeneration.

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.

The effect of local and systemic statin use as an adjunct to non-surgical and surgical periodontal therapy-A systematic review and meta-analysis

OBJECTIVES

To evaluate the effect of local and/or systemic statin use as an adjunct to non-surgical and/or surgical periodontal therapy.

DATA

Literature search according to PRISMA guidelines with the following eligibility criteria: (a) English or German language; (b) interventional studies; (c) statins as monotherapy or as an adjunct to non-surgical and/or surgical treatment of periodontitis; (d) clinical and/or radiographic treatment effect size of statin intake reported.

SOURCES

Medline (PubMed), Embase (Ovid), CENTRAL (Ovid).

STUDY SELECTION

Thirteen clinical studies regarding local application and 2 with systemic administration of statins as an adjunct to non-surgical treatment (SRP) and 4 studies regarding intrasurgical statin application with a maximum follow-up of 9 months could be included; simvastatin, atorvastatin, and rosuvastatin were used. Local but not systemic statin application as an adjunct to SRP yielded significantly larger probing pocket depth (PD), radiographic defect depth (RDD), and bleeding index reduction, and larger clinical attachment level gain, and less residual PD and RDD (p≤0.016); rosuvastatin appeared as the most efficacious. Three of 4 studies reported a significant positive effect of intrasurgical statin application. No adverse events were reported after statin use. The vast majority of the included studies were from the same research group.

CONCLUSIONS

Significant additional clinical and radiographic improvements are obtained after local, but not systemic, statin use as an adjunct to SRP in deep pockets associated with intrabony defects and seemingly with furcation defects; intrasurgical statin application seems similarly beneficial. Confirmation of these results, and especially of the effect size, from other research groups is warranted.

Clinical efficacy of a chlorhexidine-based mouthrinse containing hyaluronic acid and an antidiscoloration system in patients undergoing flap surgery: A triple-blind, parallel-arm, randomized controlled trial

OBJECTIVES

To evaluate the postsurgery gingival healing as well as plaque, gingival inflammation and staining levels following the use of a 0.2% chlorhexidine (CHX) solution with or without antidiscoloration system (ADS) and 0.2% hyaluronic acid (HA).

METHODS

Patients undergoing flap surgery at sites with an intact or reduced but healthy periodontium participated in a parallel-arm RCT. After surgery, patients used the assigned mouthrinse (CHX + HA + ADS or CHX) for 21 days. At days 7 and 21, the healing process was evaluated at experimental teeth using a composite index, namely the Gingival Healing Index (GHI). GHI score was obtained as the sum of the scores related to the severity of wound dehiscence (score 1-3) and the profile of the buccal and oral aspects of the papilla (score 1-3). Therefore, GHI ranged from 2 (worst quality of healing) to 6 (optimal quality of healing). Plaque Index (PlI), Gingival Index (GI), angulated bleeding score (AngBS), and tooth and tongue staining were also assessed.

RESULTS

In both groups, GHI assumed values of 5 or 6 at both days 7 and 21 in ≥50% of patients, and low median values of PlI, GI, AngBS and staining were observed during the 21-day period. Except for a significantly lower GI in CHX group at day 7, no other significant intergroup differences were found.

CONCLUSIONS

Postsurgery plaque control based on either CHX or CHX + HA + ADS mouthrinses results in optimal plaque control and quality of early gingival healing along with limited tooth and tongue staining.

To what extent does hyaluronic acid affect healing of xenografts? A histomorphometric study in a rabbit model

Among the many graft materials that have been used for the treatment of bone defects in oral and maxillofacial regions is xenograft. To improve osteoconductive effects of xenografts, they have been combined with various biocompatible materials, such as hyaluronic acid and bone morphogenetic protein. To determine bone-healing capacity of high molecular weight hyaluronic acid (HA) combined with xenograft in rabbit calvarial bone defects. Ten adult male New Zealand rabbits (mean weight 3 kg) were included in the study. Three 6-mm-diameter bicortical cranial defects were created on calvarial bone of all rabbits. These defects were filled as follows: a) xenograft; b) HA+xenograft; c) autograft. One month after the first operation, rabbits were sacrificed. Specimens were evaluated histomorphometrically. Considering multiple comparisons, differences regarding new bone were statistically significant between all groups (p<0.05). The volume of residual graft was significantly decreased in HA group compared to xenograft group (p=0.035). Marrow space, trabecular thickness (TbTh), trabecular width (TbWi), trabecular separation (TbSp), and number of node: number of terminus (NNd:NTm) in the autograft group were significantly better than xenograft and HA groups (p<0.05). However, regarding marrow space, TbTh, TbWi, TbSp, and NNd:NTm values, xenograft and HA groups showed similar results and the difference were not significant (p>0.05). These results support that high molecular weight hyaluronic acid could contribute to the healing of xenograft by improving the percentage of new bone formation and reducing the percentage of residual graft. However, HA did not significantly affect the quality of newly formed bone assessed by microarchitectural parameters.

Local Injection of Hyaluronic Acid Filler Improves Open Gingival Embrasure: Validation Through a Rat Model

BACKGROUND

The open gingival embrasure, the so-called black triangle, is one of the unsolved dilemmas in adult dentistry. Although various techniques have been introduced to improve black triangles, the lack of reproducible experimental models has prevented development of successful protocols to regenerate or to compensate loss of the interdental papilla. Therefore, the objective of this study is first to develop a reliable animal model of open gingival embrasure and then to validate a minimally invasive injection technique using hyaluronic acid (HA) filler to augment the interdental papilla.

METHODS

To reproduce open gingival embrasure in rats, rapid space opening was induced between the mandibular incisors by attachment of a compression spring. Loss of interdental papilla height was morphologically evaluated and calculated using standardized serial photographs, microcomputed tomography, and histologic sections. Afterward, HA fillers or phosphate-buffered saline (PBS) was locally injected, and changes in the interdental papilla were evaluated.

RESULTS

After 7 days of space opening, the margin of the interdental papilla between the mandibular incisors gradually became irregular and flat, indicating a condition similar to the open gingival embrasure (P <0.05). Local injection of HA filler induced an augmentation effect of the interdental papilla compared with injection of PBS (P <0.05). Interdental papilla became convex, and inner granules containing HA were detected within the submucosal layer after its injection.

CONCLUSIONS

Open gingival embrasure was reproduced reliably in vivo. Local injection of HA filler was validated as a meaningful minimally invasive procedure to improve open gingival embrasure.

In vitro effects of hyaluronic acid on human periodontal ligament cells

Background

Hyaluronic acid (HA) has been reported to have a positive effect on periodontal wound healing following nonsurgical and surgical therapy. However, to date, a few basic in vitro studies have been reported to investigating the potential of HA on human periodontal ligament (PDL) cell regeneration. Therefore, the aim of this study was to investigate the effect of HA on PDL cell compatibility, proliferation, and differentiation in vitro.

Methods

Either non-cross-linked (HA_ncl) or cross-linked (HA_cl) HA was investigated. Human PDL cells were seeded in 7 conditions as follows (1) Control tissue culture plastic (TCP) (2) dilution of HA_ncl (1:100), (3) dilution of HA_ncl (1:10), 4) HA_ncl directly coated onto TCP, (5) dilution of HA_cl (1:100), 6) dilution of HA_cl (1:10) and (7) HA_cl directly coated onto TCP. Samples were then investigated for cell viability using a live/dead assay, an inflammatory reaction using real-time PCR and ELISA for MMP2, IL-1 and cell proliferation via an MTS assay. Furthermore, the osteogenic potential of PDL cells was assessed by alkaline phosphatase(ALP) activity, collagen1(COL1) and osteocalcin(OCN) immunostaining, alizarin red staining, and real-time PCR for genes encoding Runx2, COL1, ALP, and OCN.

Results

Both HA_ncl and HA_cl showed high PDL cell viability (greater than 90%) irrespective of the culturing conditions. Furthermore, no significant difference in both mRNA and protein levels of proinflammatory cytokines, including MMP2 and IL-1 expression was observed. Both diluted HA_ncl and HA_cl significantly increased cell numbers compared to the controlled TCP samples at 3 and 5 days. HA_ncl and HA_cl in standard cell growth media significantly decreased ALP staining, COL1 immunostaining and down-regulated early osteogenic differentiation, including Runx2, COL1, and OCN mRNA levels when compared to control samples. When osteogenic differentiation medium (ODM) was added, interestingly, the expression of early osteogenic markers increased by demonstrating higher levels of COL1 and ALP expression; especially in HA 1:10 diluted condition. Late stage osteogenic markers remained inhibited.

Conclusions

Both non-cross-linked and cross-linked HA maintained high PDL cell viability, increased proliferation, and early osteogenic differentiation. However, HA was consistently associated with a significant decrease in late osteogenic differentiation of primary human PDL cells. Future in vitro and animal research is necessary to further characterize the effect of HA on periodontal regeneration.

Can hyaluronan injections augment deficient papillae at implant-supported crowns in the anterior maxilla? A randomized controlled clinical trial with 6 months follow-up

OBJECTIVES

The present randomized controlled trial aimed to assess the effect of hyaluronan (HY) injections to augment deficient interproximal papillae at implant-supported crowns in the anterior maxilla.

METHODS

Twenty-two patients with a deficient papilla in the anterior maxilla next to an implant-supported crown were randomly assigned to receive twice either HY (test) or saline solution (control) injection. The following parameters were recorded prior to injection (baseline) and 3 and 6 months after injection: distance between the papilla tip and contact point (PT-CP), modified papilla index score (MPIS), and standard clinical periodontal parameters. Pain level after injection was recorded on a visual analogue scale (VAS). The deficient area was evaluated on clinical photographs, and the esthetic appearance was recorded on a VAS. Differences in mucosal volume were assessed after 3 months by intraoral scans. The bone level was assessed on periapical radiographs.

RESULTS

No differences were observed between groups, neither at baseline nor at 3 and 6 months post-treatment. Mean PT-CP ranged between 1.8 mm and 2.3 mm without significant differences between groups or over time within groups; MPIS was 2 for all patients at all time points. Similarly, insignificant differences between groups or time points were observed for deficient area, gingival volume changes, bone level, and esthetic appearance. There were no differences in pain level between groups during injection, but discomfort after injection lasted longer in the test group.

CONCLUSIONS

Injection of HY adjacent to maxillary anterior implant-supported crowns did not result in any clinical conspicuous volume augmentation of deficient papillae.

Hyaluronic acid: Perspectives in dentistry. A systematic review

To date, topical therapies guarantee a better delivery of high concentrations of pharmacologic agents to the soft periodontal tissue, gingiva, and periodontal ligament as well as to the hard tissue such as alveolar bone and cementum. Topical hyaluronic acid (HA) has recently been recognized as an adjuvant treatment for chronic inflammatory disease in addition to its use to improve healing after dental procedures. The aim of our work was to systematically review the published literature about potential effects of HA as an adjuvant treatment for chronic inflammatory disease, in addition to its use to improve healing after common dental procedures. Relevant published studies were found in PubMed, Google Scholar, and Ovid using a combined keyword search or medical subject headings. At the end of our study selection process, 25 relevant publications were included, three of them regarding gingivitis, 13 of them relating to chronic periodontitis, seven of them relating to dental surgery, including implant and sinus lift procedures, and the remaining three articles describing oral ulcers. Not only does topical administration of HA play a pivotal key role in the postoperative care of patients undergoing dental procedures, but positive results were also generally observed in all patients with chronic inflammatory gingival and periodontal disease and in patients with oral ulcers.

Adverse reaction after hyaluronan injection for minimally invasive papilla volume augmentation. A report on two cases

OBJECTIVES

To report two cases of adverse reaction after mucosal hyaluronan (HY) injection around implant-supported crowns, with the aim to augment the missing interdental papilla.

MATERIAL AND METHODS

Two patients with single, non-neighbouring, implants in the anterior maxilla, who were treated within the frames of a randomized controlled clinical trial testing the effectiveness of HY gel injection to reconstruct missing papilla volume at single implants, presented an adverse reaction. Injection of HY was performed bilaterally using a 3-step technique: (i) creation of a reservoir in the mucosa directly above the mucogingival junction, (ii) injection into the attached gingiva/mucosa below the missing papilla, and (iii) injection 2-3 mm apically to the papilla tip. The whole-injection session was repeated once after approximately 4 weeks.

RESULTS

Both patients presented with swelling and extreme tenderness with a burning sensation on the lip next to the injection area, after the second injection session. In one of the cases, a net-like skin discoloration (livedo reticularis) was also noted. The symptoms lasted for up to 7 days, and in both cases, symptoms resolved without any signs of skin or mucosal necrosis or any permanent damage.

CONCLUSION

Most likely, water attraction over time by the highly hygroscopic HY, exerted progressively an external vascular compression and at least partial occlusion of neighbouring blood vessels. An infection or an allergic reaction seems unlikely, since all symptoms gradually disappeared within a week irrespective use of antimicrobials, while an allergic reaction most likely would not have been restricted to one side.

Hyaluronic Acid Improves Bone Formation in Extraction Sockets With Chronic Pathology: A Pilot Study in Dogs

BACKGROUND

Previous studies on ridge preservation focusing on fresh extraction sockets using graft materials for ridge preservation procedures have reported a delay in the tissue modeling and remodeling phases. The objective of this study is to evaluate the effect of hyaluronic acid (HA) on healing of infected sockets.

METHODS

Six beagle dogs were used in this study. Both mandibular third premolars were hemisected, and the distal roots were extracted. Subsequently, periodontal and endodontic lesions were induced at the remaining mesial root. After communication of the periodontal lesion, an endodontic periapical lesion was observed at 4 months, and the mesial roots of both the right and left sides were extracted. HA was applied into the socket of the test group, and no treatment was administered to the other group (control group). Three months after extraction of the mesial roots, the dogs were sacrificed, and histologic evaluations were performed.

RESULTS

The sockets were filled by mineralized bone (47.80% ± 6.60%) and bone marrow (50.47% ± 6.38%) in the control group, whereas corresponding values were 63.29% ± 9.78% and 34.73% ± 8.97% for the test group, respectively. There was a statistically significant difference between the groups. Reversal lines and a copious lineup of osteoblasts were observed in the middle and apical parts of the sockets in the test group.

CONCLUSION

An infected socket shows delayed healing of the socket wound, and HA, because of its osteoinductive, bacteriostatic, and anti-inflammatory properties, may improve bone formation and accelerate wound healing in infected sockets.

To compare the effect of the local delivery of hyaluronan as an adjunct to scaling and root planing versus scaling and root planing alone in the treatment of chronic periodontitis

Background:

Hyaluronan is a critical component of the extracellular matrix and contributes significantly to tissue hydrodynamics and cell migration and proliferation. Studies have demonstrated its anti-inflammatory, antibacterial, and regenerative effects. The present study aimed to assess the clinical effects of the subgingival application of 0.8% hyaluronic acid gel as an adjunct to scaling and root planing (SRP) in the treatment of generalized chronic periodontitis.

Materials and Methods:

Patients with chronic periodontitis were recruited to participate in a study with a split-mouth design and provided informed consent. One hundred sites were included in the study and divided into fifty test sites and fifty control sites. These were assessed for plaque index (PI), gingival index (GI), pocket probing depths, and relative attachment level (RAL) at-pretreatment (baseline), 4, and 12 weeks posttreatment. The patients received full-mouth SRP. A 0.8% hyaluronan gel was administered subgingivally in the test sites at baseline and after 1 week. Significant differences between test and control were evaluated using the t-test, analysis of variance (test) followed by Bonferroni post hoc test.

Results:

A significant reduction in PI and GI was observed in both groups at 12 weeks (P < 0.05). Significant reduction in the pocket probing depths and gain RAL was observed in both the groups as compared to baseline (P < 0.05). The hyaluronan group compared to control at 12 weeks showed statistically significant reduction in the probing pocket depth and gain in RAL (P < 0.05).

Conclusion:

The subgingival application of 0.8% hyaluronan gel in conjunction with SRP may have a beneficial effect on periodontal health in patients with chronic periodontitis.

A chitosan-hyaluronic acid hydrogel scaffold for periodontal tissue engineering

The current challenge in treating periodontitis is regenerating the periodontium. This motivates tissue-engineering researchers to develop scaffolds as artificial matrices that give mechanical support for osteoblasts, cementoblasts, gingival and periodontal ligament fibroblast cells. In this study, modified hyaluronic acid (HA) and chitosan (CS) were employed to create a hybrid CS-HA hydrogel scaffold for periodontal regeneration. CS, HA, and CS-HA scaffolds were obtained by freeze-drying technique, resulting in porous structures suitable for use in tissue engineering. Scaffolds were submitted to gamma and UV-sterilization without significant morphology changes. The ATR-FTIR spectra of CS-HA hydrogels showed peaks at 377 cm^-1 , 1566 cm^-1 , and 1614 cm^-1 , representing secondary amide, primary amine, and carboxyl acid respectively, and it was also observed the emergence of peaks at 886 cm^-1 , which probably represents the Schiff base formed in the case of hybrid CS-HA hydrogels. The scaffolds presented a high rate of PBS uptake, reaching values higher than 95%. Thermal degradation of HA scaffolds was around 225°C and CS was around 285°C. The ATR-FTIR spectra and swelling degree were slightly disturbed mainly after gamma sterilization, but degradation temperature did not change after sterilization. The performance of the CS-HA hydrogel scaffolds for in vitro cell culture was tested using NIH3T3 and MG63 cell lines. The Alamar Blue test showed a significant increase in cellular viability and high CD44 expression, suggesting that the cells migrated more when seeded onto the scaffolds. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1691-1702, 2016.