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.

Use of platelet-rich fibrin for the treatment of gingival recessions: a systematic review and meta-analysis.

OBJECTIVES: The aim of this systematic review and meta-analysis was to compare the use of platelet-rich fibrin (PRF) with other commonly utilized treatment modalities for root coverage procedures. MATERIALS AND METHODS: The eligibility criteria comprised randomized controlled trials (RCTs) comparing the performance of PRF with that of other modalities in the treatment of Miller class I or II (Cairo RT I) gingival recessions. Studies were classified into 5 categories as follows: (1) coronally advanced flap (CAF) alone vs CAF/PRF, (2) CAF/connective tissue graft (CAF/CTG) vs CAF/PRF, (3) CAF/enamel matrix derivative (CAF/EMD) vs CAF/PRF, (4) CAF/amnion membrane (CAF/AM) vs CAF/PRF, and (5) CAF/CTG vs CAF/CTG/PRF. Studies were evaluated for percentage of relative root coverage (rRC; primary outcome), clinical attachment level (CAL), keratinized mucosa width (KMW), and probing depth (PD) (secondary outcomes). RESULTS: From 976 articles identified, 17 RCTs were included. The use of PRF statistically significantly increased rRC and CAL compared with CAF alone. No change in KMW or reduction in PD was reported. Compared with PRF, CTG resulted in statistically significantly better KMW and RC. No statistically significant differences were reported between the CAF/PRF and CAF/EMD groups or between the CAF/PRF and CAF/AM groups for any of the investigated parameters. CONCLUSIONS: The use of CAF/PRF improved rRC and CAL compared with the use of CAF alone. While similar outcomes were observed between CAF/PRF and CAF/CTG for CAL and PD change, the latter group led to statistically significantly better outcomes in terms of rRC and KTW. In summary, the use of PRF in conjunction with CAF may represent a valid treatment modality for gingival recessions exhibiting adequate baseline KMW. CLINICAL RELEVANCE: The data indicate that the use of PRF in conjunction with CAF statistically significantly improves rRC when compared with CAF alone but did not improve KMW. Therefore, in cases with limited baseline KMW, the use of CTG may be preferred over PRF.

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-ß3, 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.

Hyaluronic acid slows down collagen membrane degradation in uncontrolled diabetic rats.

AIM: To examine the in vitro biokinetics of hyaluronic acid (HA) from a collagen membrane (CM) and to evaluate the in vivo effect of immersion of the CM in HA solution on its degradation in streptozotocin (STZ)-induced diabetes conditions in a rat calvaria subcutaneous model. BACKGROUND: CM degradation is accelerated in uncontrolled diabetic rats. Immersion of CM in HA has been suggested to decrease their resorption rate without interfering with their tissue integration and structural degradation. However, it is unknown to what extent CM degradation may be influenced by its immersion in HA solution under a condition mimicking a medically compromised situation with an increased inflammatory level such as diabetes. MATERIALS AND METHODS: CMs were soaked in cross-linked HA. Protein adsorption and the HA release were quantified by ELISA. Diabetes was induced in sixteen rats, while 16 healthy rats served as control. CM was prepared and labeled prior to implantation with Biotin. Seventeen CM were immersed in HA and 17 CM in PBS. In each animal, one test or one control disk was implanted. In order to compare the collagen content, two similar non-implanted CM were used as baseline. Fourteen days after surgery, thirty-two animals were sacrificed. The entire calvaria including the skin above, was chemically fixed, decalcified, and embedded in paraffin. Five-µm-thick sections were analyzed histologically and histomorphometrically using H&E and avidin-peroxidase staining. RESULTS: The in vitro results demonstrated that the CM adsorbed roughly 80% of the total HA content. After 10 days, 36.3% of the initial HA remained on the CM. The in vivo results demonstrated that diabetes significantly reduced the thickness of the CM, while HA had a significant effect on keeping the membrane thickness. HA increased the residual collagen content in the diabetic group (P < 0.0001) but no such effect was observed in the healthy group. CONCLUSION: Immersion of CM in HA prior to the implantation delays membrane degradation in uncontrolled diabetic compared with normoglycemic rats.

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.

Accelerated degradation of collagen membranes in diabetic rats is associated with increased infiltration of macrophages and blood vessels.

OBJECTIVES: Increased collagenolytic activity in diabetes may compromise collagen membrane (CM) survival. Tetracycline (TTC) possesses anti-collagenolytic properties and delays CM degradation. This study evaluated macrophage and capillary infiltration within CMs in diabetic rats. MATERIALS AND METHODS: Diabetes was induced in 20 Wistar rats by streptozotocin and 20 served as controls. Biotin-labeled CM discs were immersed in either TTC (50 mg/ml) or PBS. In each animal, 2 discs (TTC and control) were implanted under the parietal periosteum and rats were sacrificed at 2 or 4 weeks post-implantation. The area and thickness of the residual disc collagen were measured following staining with streptavidin, and the number of macrophages and blood vessels within the membranes was determined using specific antibodies (to CD68 and transglutaminase II, respectively). RESULTS: Diabetes significantly reduced the area and thickness of the CMs, while TTC increased CM thickness significantly in both groups of rats at 2 and 4 weeks. Diabetes increased the number of macrophages (∼eightfold at 2 weeks and ∼fourfold at 4 weeks), but TTC had no significant effect. Finally, diabetes increased the number of blood vessels within the discs (∼threefold at 2 weeks and ∼twofold at 4 weeks), while TTC had no effect. CONCLUSIONS: Diabetes increases degradation of native CMs and the number of blood vessels and macrophages within them. TTC immersion delays CM degradation without an apparent effect on macrophage and blood vessel penetration. CLINICAL RELEVANCE: Enhanced CM degradation in diabetic conditions which impair guided regenerative procedure outcome is apparently related to increased blood vessel formation and macrophage infiltration.

Reconstructive Approach in Residual Periodontal Pockets with Biofunctionalized Heterografts-A Retrospective Comparison of 12-Month Data from Three Centers.

The regenerative capacity of well-preserved blood clots may be enhanced by biologics like enamel matrix derivative (EMD). This retrospective analysis compares outcomes reported by three centers using different heterografts. Center 1 (C1) treated intrabony defects combining cross-linked high-molecular-weight hyaluronic acid (xHyA) with a xenograft; center 2 (C2) used EMD with an allograft combination to graft a residual pocket. Center 3 (C3) combined xHyA with the placement of a resorbable polymer membrane for defect cover. Clinical parameters, BoP reduction, and radiographically observed defect fill at 12-month examination are reported. The 12-month evaluation yielded significant improvements in PPD and CAL at each center (p < 0.001, respectively). Analyses of Covariance revealed significant improvements in all parameters, and a significantly greater CAL gain was revealed for C2 vs. C1 (p = 0.006). Radiographic defect fill presented significantly higher scores for C2 and C3 vs. C1 (p = 0.003 and = 0.014; C2 vs. C3 p = 1.00). Gingival recession increased in C1 and C3 (p = 1.00), while C2 reported no GR after 12 months (C2:C1 p = 0.002; C2:C3 p = 0.005). BoP tendency and pocket closure rate shared similar rates. Within the limitations of the study, a data comparison indicated that xHyA showed a similar capacity to enhance the regenerative response, as known for EMD. Radiographic follow-up underlined xHyA's unique role in new attachment formation.

Clinical Evaluation of a Novel Combination of Sodium Hypochlorite/Amino Acid and Cross-linked Hyaluronic Acid Adjunctive to Non-surgical Periodontal Treatment: A Case Series.

PURPOSE: The adjunctive subgingival application of sodium hypochlorite/amino acid and a mixture of natural and cross-linked hyaluronic acid gels (high molecular weight) has been recently proposed as a novel modality to enhance the outcomes of non-surgical periodontal therapy. The aim of this prospective case series was to evaluate the clinical outcomes obtained following the subgingival application of a combination of sodium hypochlorite/amino acid and a mixture of natural and cross-linked hyaluronic acid (high molecular) gels in conjunction with non-surgical periodontal therapy. MATERIAL AND METHODS: Twenty-one systemically healthy, non-smoking patients diagnosed with stage II-III, grade A/B periodontitis underwent full-mouth subgingival debridement (SD) performed with ultrasonic and hand instruments. All sites with probing depths (PD) ≥ 4 mm were treated with additional repeated (i.e., 2-3 times) instillation of sodium hypochlorite/amino acid gel in the periodontal pockets prior to and during SRP. Following mechanical debridement, a mixture of natural and cross-linked hyaluronic acid (high molecular) gel was applied in the pockets. The primary outcome variable was PD reduction; changes in clinical attachment level (CAL) and bleeding on probing (BOP) were the secondary outcomes. The clinical parameters were assessed at baseline, 3 and 6 months after therapy. RESULTS: Compared to baseline, a statistically significant mean reduction of PD values was obtained after 3 and 6 months, amounting to 2.6 ± 0.4 mm, and 2.9 ± 0.4 mm, respectively (p < 0.001). Mean CAL gain measured 2.3 ± 0.5 mm at 3 months and 2.6 ± 0.5 mm at 6 months in comparison to baseline (p < 0.001). Mean reduction of BOP values was 54.9 ± 16.9 % at 3 months and 65.6 ± 16.4 % at 6 months (p < 0.001). The number of moderate pockets (4-5 mm) decreased from 1808 at baseline to 274 at the 6-month evaluation, and the number of deep (≥ 6 mm) pockets dropped from 319 to 3, respectively. CONCLUSION: The combination of sodium hypochlorite/amino acid and a mixture of natural and cross-linked hyaluronic acid (high molecular) adjunctive to subgingival debridement may represent a valuable approach to improve the outcomes of non-surgical periodontal treatment.

Sodium Hypochlorite as an Adjunct to Nonsurgical Treatment of Periodontitis: A Systematic Review.

PURPOSE: To evaluate effects of the adjunctive subgingival application of sodium hypochlorite on clinical outcome following nonsurgical periodontal treatment. MATERIALS AND METHODS: A search protocol was developed to answer the following focused question: 'in patients with periodontitis, does adjunctive subgingival application of sodium hypochlorite have additional clinical benefits compared to subgingival debridement alone?' Randomised controlled clinical trials (RCTs) published up to January 30, 2020, with at least 6 months of follow-up, in which sodium hypochlorite was used as an adjunct in nonsurgical periodontitis treatment were included. The search was limited to the English language. RESULTS: Out of 355 studies retrieved, the search resulted in two publications that fulfilled the inclusion criteria. The adjunctive application of sodium hypochlorite did not provide additional beneficial effect in terms of changes in the evaluated clinical outcomes (i.e. probing depth values [PDs], clinical attachment level gain [CAL] and bleeding on probing [BOP]) when compared to mechanical instrumentation alone over the 12-month investigation period (p > 0.05). CONCLUSION: The available data have failed to show any additional clinical benefit following the use of sodium hypochlorite in conjunction with nonsurgical periodontal therapy.

Treatment of single mandibular recessions with the modified coronally advanced tunnel or laterally closed tunnel, hyaluronic acid, and subepithelial connective tissue graft: a report of 12 cases.

OBJECTIVES: To clinically evaluate the healing of mandibular Miller Class I and II isolated gingival recessions treated with the modified coronally advanced tunnel (MCAT) or laterally closed tunnel (LCT) combined with hyaluronic acid (HA) and subepithelial connective tissue graft (SCTG). METHOD AND MATERIALS: Twelve healthy patients exhibiting one isolated mandibular Miller Class I or II (Cairo Class 1) gingival recession of a depth of ≥ 3 mm, were consecutively treated with the MCAT or LCT in conjunction with HA and SCTG. Treatment outcomes were assessed at baseline and at least 6 months postoperatively. The primary outcome variable was complete root coverage (CRC). RESULTS: Postoperative pain and discomfort were low and no complications such as postoperative bleeding, allergic reactions, abscesses, or loss of SCTG occurred. After a mean follow-up of 18.9 ± 10 months, statistically significant (P < .0001) root coverage was obtained in all 12 defects. CRC was measured in six out of the 12 cases (50%), four cases showed a root coverage of over 95%, while the remaining two cases reached 80% and 85%. Mean root coverage was 96.09%. Mean keratinized tissue width increased from 1.6 ± 0.8 mm to 4.9 ± 1.3 mm (P < .0001) from baseline to follow-up, while mean probing depth showed no statistically significant changes (1.8 ± 0.9 mm vs 1.3 ± 0.5 mm). CONCLUSION: Within their limits, the present results indicate that the described treatment approach may lead to predictable root coverage of isolated mandibular Miller Class I and II (Cairo Class 1) gingival recessions. (Quintessence Int 2020;51:456-463; doi: 10.3290/j.qi.a44492).

Oral lichen planus and dental implants--a retrospective study.

OBJECTIVES: To examine whether oral lichen planus (OLP) affects the success rate of dental implants and if the manifestations of OLP are altered by implant-borne prostheses. MATERIALS AND METHODS: OLP patients, treated in the oral medicine department, with (the study group) and without (control group) dental implants were included. Pocket depth, mobility, bleeding on probing, erythema, pain and radiolucency around the implants, as well as clinical findings and OLP symptoms were recorded. Follow-up ranged from 12-24 months. Ordinal variables and visual analog scale score were compared using the Mann-Whitney test. The significance of the trend within each of the groups was assed using the Friedman test. Categorical variables were compared using Pearson chi-squared test and Fisher's exact test. RESULTS: Fourteen patients in the study group with 1-15 implants per patient and 15 in the control group were included. No implant failures were recorded. Comparison between the clinical manifestations of OLP in both groups did not reveal any significant differences. CONCLUSIONS: Success of implant rehabilitation among treated OLP patients does not seem to be different from the success rate in the general population. Nor does implant placement influence the disease manifestations.

Opposing effects of diabetes and tetracycline on the degradation of collagen membranes in rats.

BACKGROUND: Increased collagenolytic activity, characteristic of uncontrolled diabetes, may compromise collagen membrane (CM) survival. Tetracycline (TCN) possesses anticollagenolytic properties and delays CM degradation in healthy animals. This study evaluates the degradation of TCN--immersed and -non-immersed CMs in rats with diabetes compared to those with normoglycemia. METHODS: Diabetes was induced in 15 12-week-old male Wistar rats by injection of 65 mg/kg streptozotocin. The control group consisted of 15 rats with normoglycemia. Sixty bilayered CM disks were labeled before implantation with aminohexanoyl-biotin-N-hydroxy-succinimide ester, of which 30 were immersed in 50 mg/mL TCN solution (experimental) or phosphate-buffered saline (PBS) (control). In each animal, two disks (control and experimental) were implanted in two midsagittal calvarial defects in the parietal bone. Similar non-implanted disks served as baseline. After 3 weeks, animals were euthanized, and the calvaria and overlying soft tissues were processed for demineralized histologic analysis. Horseradish peroxidase-conjugated streptavidin was used to detect the biotinylated collagen. The area of residual collagen within the membrane disks was measured and analyzed with a digital image analysis system. Several slides from each specimen were also stained with hematoxylin and eosin. Statistical analysis consisted of paired and unpaired t tests. RESULTS: The amount of residual collagen in PBS-immersed disks was lower in rats with diabetes compared to rats with normoglycemia (69% of baseline versus 93%, respectively, P <0.001). TCN immersion increased the amount of residual collagen contents in both diabetic (83% of baseline) and healthy (97.5% of baseline) animals (P <0.0001). CONCLUSION: Diabetes increases CM degradation, whereas immersion in 50 mg/mL TCN solution before implantation presents an opposite effect.