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

Comparative Study on Interdental Papillae Regeneration: Leukocyte Platelet-Rich Fibrin By-product versus Hyaluronic Acid Injections in Modified Open Gingival Embrasure Model

OBJECTIVES

 This study aims to compare the regenerative effects of various by-products of human leukocyte platelet-rich fibrin (L-PRF), including L-PRF exudate, concentrated PRF (C-PRF), and a mixture of the two, with hyaluronic acid (HA) specifically for interdental papillae reconstruction.

MATERIALS AND METHODS

 The L-PRF was obtained by centrifuging 10 mL of human blood in a fixed-angle centrifuge at 2,700 rpm for 12 minutes. After centrifugation, the L-PRF layer was separated, and platelet and leukocyte counts were performed. An in vivo study was conducted using Sprague-Dawley rats subjected to a modified open gingival embrasure (OGE) model for 7 days. Once the OGE was established, 20 µL of L-PRF exudate (n = 3), C-PRF (n = 3), a combination of L-PRF exudate and C-PRF (n = 3), HA (n = 3), and phosphate-buffered saline (n = 3) were injected 2 mm from the tip of the papillae using a 30G syringe. Clinical parameters, including OGE width and spring papilla distance (SPD), were observed on days 7 and 14. On day 14, histological observations included fibroblast count, blood vessel presence, epithelial width, and collagen density, while proliferating cell nuclear antigen expression was assessed immunohistochemically.

STATISTICAL ANALYSIS

 The SPD on day 7, along with all histological and immunohistochemical data, were normally distributed and analyzed by one-way analysis of variance followed by Tukey's honestly significant difference test. In contrast, the Kruskal-Wallis' test was used to analyze the OGE width and SPD on day 14, which was not normally distributed.

RESULTS

 The cell counts indicated that most platelets and leukocytes were in the C-PRF layer. The L-PRF membrane by-product increased fibroblast proliferation more effectively than HA (p < 0.05). Only C-PRF significantly enhanced the vascularization and epithelialization of the papillae (p < 0.05). However, the observed cellular and molecular changes increased at day 7 postinjection and did not impact collagen density or interdental papilla height.

CONCLUSION

 The regenerative effect of C-PRF injection is superior to that of HA and other L-PRF by-products, as it promotes papillae regeneration by enhancing fibroblast activity, vascularization, and epithelialization. These findings show the potential impact of L-PRF by-products as a nonsurgical papillae reconstruction treatment.

Comparison of the effect of albumin with platelet-rich fibrin (Alb-PRF) gel and hyaluronic acid gel injection on interdental papilla reconstruction: A randomized clinical trial

Background

The interdental papilla plays a crucial role in the esthetic of the smile. Papilla reconstruction surgery is one of the most unpredictable periodontal procedures. This study compared the effect of the non-surgical application of a commercial hyaluronic acid (HA) gel with an autogenous gel named "albumin with platelet-rich fibrin" (Alb-PRF) on interdental papilla reconstruction.

Methods

This trial was conducted on 46 incomplete interdental papillae with class I or II defects. The papillae were randomly divided into two experimental groups, and commercial HA or Alb-PRF (prepared from the patient's peripheral blood) was injected into the papillae twice at a 21-day interval. Three and six months after the intervention, photographs were taken from the black triangles and the black surfaces compared to each other. Patient satisfaction and dental plaque index were also evaluated at the end of the study.

Results

The black triangles' surfaces significantly decreased over time in both experimental groups (P<0.001). However, there were no significant differences between the two groups (P=0.994). The intervention resulted in the patients' relative satisfaction with the treatment results in both groups. However, the difference between the two groups was not statistically significant (P=0.965). In addition, no statistically significant differences were observed in plaque index between the two groups (P=0.566).

Conclusion

HA or Alb-PRF injection into the incomplete interdental papilla may restore the soft tissue to a great extent and lead to patient satisfaction by reducing the area of black triangles that threaten esthetics; however, more studies are needed.

Histologic Evaluation of Early Papilla Healing after Augmentation with Injectable Hyaluronic Acid-A Proof of Concept

Objectives: This human histological study's purpose was to histologically evaluate papillae's healing after hyaluronic acid (HA) gel augmentation at three healing time points after one injection with hyaDENT BG®. Methods: Fifteen papillae from two patients with stage III, grade B periodontitis have been selected for this study. Every week for three weeks, five papillae were injected once with HA gel, and during the fourth week, the papillae were surgically removed as part of step 3 of the periodontal treatment. The histological analysis was performed on fifteen papillae, with five papillae corresponding to every timepoint of healing (weeks 1, 2, and 3). The primary outcome was considered to be the newly formed collagen fibers. The presence of residual HA, the integrity of epithelium or the presence of erosions/ulcerations, the presence and characteristics of inflammatory infiltrate, the presence of granulomatous reactions, and interstitial edema were considered to be secondary outcomes. Results: From the first to the third week, newly formed connective tissue begins to appear, while the observed HA pools (vesicles) content decreases. The density of inflammatory infiltrate was higher in the first week after injection, decreasing considerably by week 3; however, it was still visible throughout the healing time points. A granulomatous reaction was present in only three samples, while no signs of ulceration or necrosis could be observed; however, epithelial erosions could be observed on some samples after the first week. Conclusions: Papila augmentation with hyaluronic acid promotes new collagen formation from the second week of healing despite some foreign body granulomatous reactions.

Evaluation of Interdental Papilla Regeneration Using Injectable Hyaluronic Acid: A Clinical Study

AIM

This study aimed to assess the efficacy of hyaluronic acid (HA) gel injections in deficient papillae and record the effects for four weeks.

MATERIALS AND METHODS

Fifteen deficient class 1 papilla sites according to Nordland and Tarnow classification were included. After scaling and root planing, 0.5 ml HA gel was injected into the papillae. Measurements of black triangle height (BTH) and black triangle area (BTA) from the contact point to the most coronal level of the visible papilla tip were done on the clinical photographs using ImageJ software at baseline, one week, and four weeks postoperatively, and a comparison was made. Descriptive data were examined using the mean and standard deviation (SD). Paired t-test was used for intragroup comparisons, with p-values <0.05 considered significant. All the data analysis was done using SPSS software version 25.0.

RESULTS

There was a mean decrease in the BTA from baseline (0.54 mm2), one week (0.13 mm2), to four weeks (0.26 mm2) with a slight loss of papilla volume from the first week to the fourthweek, and this decrease in area was statistically significant. A mean decrease in the BTH throughout the follow-ups from baseline (1.36 mm) to the first week (0.30 mm) to the fourth week (0.73) was recorded with a slight loss of papilla volume from the first week to the fourthweek, and this decrease in height was also statistically significant (p < 0.05). However, the decrease in the BTA and BTH recorded was more from baseline to the first week as compared to baseline to the fourth week postoperatively.

CONCLUSION

HA gel is an effective treatment for minimally invasive papilla augmentation, particularly in class I Nordland and Tarnow papilla deficits.

The use of hyaluronic acid injection for treatment of black triangle and reconstruction of lost interdental papilla in anterior teeth: a systematic review

OBJECTIVE

Non-surgical therapeutics to reconstruct lost interdental papilla are evolving; these include hyaluronic acid injection. The aim of this systematic review is to evaluate the efficacy, safety, and long-term outcomes of hyaluronic acid injection in the treatment of black triangles and reconstruction of lost interdental papilla in anterior teeth.

MATERIALS AND METHODS

The protocol was registered in PROSPERO (CRD42023446875) and in accordance with the Cochrane Handbook of Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis 'PRISMA'. The search involved four databases, PubMed/MEDLINE, The Cochrane Library, Google Scholar, and ProQuest for ''grey literature' with additional manual search for studies published up to May 2024. Human clinical studies of a prospective nature (randomised clinical trials and prospective cohort studies) were included. Exclusion criteria were case reports, case series, review articles, letter to editor, personal opinion, and animal studies. Furthermore, studies which utilised hyaluronic acid injection in conjunction with other therapeutic material, tissue graft, or any surgical procedure were also excluded. The data were extracted independently by the two authors and incorporated after consensus. The risk of bias was assessed using the RoB2: the revised Cochrane risk of bias tool for randomised clinical trials and the Newcastle Ottawa scale for prospective cohort studies.

RESULTS

24 studies, 15 prospective clinical studies and nine randomised clinical trials, were included with a total of 898 interdental papillae injected with hyaluronic acid. The studies showed promising outcomes in the reconstruction of lost interdental papilla with minimal adverse reactions. Risk of bias assessment among prospective clinical studies revealed 13 good quality studies with only two poor studies while the randomised clinical trials consisted of three with low, one with some concern, and five studies with high risk of bias. However, due to the high heterogeneity, a meta-analysis was not feasible.  Conclusion: Hyaluronic acid injection is an effective minimally invasive approach in treating black triangles and reconstructing lost interdental papilla in the anterior teeth. Further long-term well-designed randomised clinical trials employing standardised procedures are essential to validate this treatment and provide better quality of evidence.

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.

Hydrogel based soft tissue expanders for orodental reconstruction

Tension-free flap closure to prevent soft tissue dehiscence is a prerequisite for successful bone augmentation in orodental reconstructive surgery. Since soft tissue contour follows the underlying jaw bony architecture, resorption of alveolar (jaw) bone limits the availability of soft tissue for wound closure following major bone reconstruction, required to facilitate oral rehabilitation with endosseous dental implants following tooth loss. Although there are several clinical procedures to increase soft tissue volume, these techniques are complicated and technically demanding. Soft tissue expansion, an established technique in reconstructive surgery, is an ideal alternative to generate surplus soft tissue prior to bone augmentation and dental implant placement. Increase in tissue volume can be achieved by using soft tissue expanders (STEs). Contemporary STEs have evolved from silicone balloons to osmotically inflating hydrogel-based systems. Here, we provide an overview of STEs in clinical oral surgery, outline the current research in STEs, and an update on recent clinical trials as well as the associated complications. Also, the mechanism governing soft tissue expansion and the critical factors that control the expansion process are covered. Design considerations for STEs for intraoral applications are given particular attention. Finally, we present our perspectives on utilization of minimally invasive methods to administer STEs for orodental applications. STATEMENT OF SIGNIFICANCE: Soft tissue expansion is required for a range of reconstructive applications and more notably in regenerative dentistry for vertical bone augmentation. This review describes the commercially available soft tissue expanders along with the latest systems being currently developed. This review insightfully discusses the biological and physical mechanisms leading to soft tissue expansion and critically assesses the design criteria of soft tissue expanders. A particular focus is given on the development of a new generation of hydrogel-based soft tissue expanders; their chemistry and required physical properties for tissue expansion is described and the obstacles towards clinical translations are identified. Finally, the review elaborates on promising minimally invasive injectable hydrogel-based tissue expanders and highlights the beneficial features of these systems.

Unilateral hard palate necrosis following gingival injections with hyaluronic acid

Hyaluronic acid (HA) injections into the oral mucosa have proven to be effective as a non-invasive method for the reconstruction of interproximal papillary defects in aesthetic areas. Despite being a minimally invasive and safe technique, certain side effects may occur after treatment.We report the first case of a patient with unilateral necrosis of the mucosa of the hard palate after HA filling in the maxillary anterior gingiva. Familiarity with these events and competent knowledge of the anatomy is essential to avoid complications, achieve and offer adequate treatment and good results to our patients.

Transcriptomic Analysis in Human 3D Skin Model Injected with Resorbable Hyaluronic Acid Fillers Reveals Foreign Body Response

Usage of injectable dermal fillers applied for aesthetic purposes has extensively increased over the years. As such, the number of related adverse reactions has increased, including patients showing severe complications such as product migration, topical swelling and inflammatory reactions of the skin. In order to understand the underlying molecular events of these adverse reactions we performed a genome-wide gene expression study on the multi-cell type human Phenion® Full-Thickness Skin Model exposed to five experimental hyaluronic acid (HA) preparations with increasing cross-linking degree, four commercial fillers from Perfectha®, and non-resorbable filler Bio-Alcamid®. In addition, we evaluated whether cross-linking degree or particle size of the HA-based fillers could be associated with the occurrence of adverse effects. In all cases, exposure to different HA fillers resulted in a clearly elevated gene expression of cytokines and chemokines related to acute inflammation as part of the foreign body response. Furthermore, for one experimental filler genes of OXPHOS complexes I-V were significantly down-regulated (adjusted p-value < 0.05), resulting in mitochondrial dysfunction which can be linked to over-expression of pro-inflammatory cytokines TNFα and IL-1β and chemokine CCL2. Our hypothesis that cross-linking degree or particle size of the HA-based fillers is related to the biological responses induced by these fillers could only partially be confirmed for particle size. In conclusion, our innovative approach resulted in gene expression changes from a human 3D skin model exposed to dermal fillers that mechanistically substantiate aforementioned adverse reactions, and thereby adds to the weight of evidence that these fillers may induce inflammatory and fibrotic responses.

Evaluation of Adverse Effects of Resorbable Hyaluronic Acid Fillers: Determination of Macrophage Responses

Resorbable tissue fillers for aesthetic purposes can induce severe complications including product migration, late swelling, and inflammatory reactions. The relation between product characteristics and adverse effects is not well understood. We hypothesized that the degree of cross-linking hyaluronic acid (HA) fillers was associated with the occurrence of adverse effects. Five experimental HA preparations similar to HA fillers were synthesized with an increasing degree of cross-linking. Furthermore, a series of commercial fillers (Perfectha^®) was obtained that differ in degradation time based on the size of their particulate HA components. Cytotoxic responses and cytokine production by human THP-1-derived macrophages exposed to extracts of the evaluated resorbable HA fillers were absent to minimal. Gene expression analysis of the HA-exposed macrophages revealed the responses related to cell cycle control and immune reactivity. Our results could not confirm the hypothesis that the level of cross-linking in our experimental HA fillers or the particulate size of commercial HA fillers is related to the induced biological responses. However, the evaluation of cytokine induction and gene expression in macrophages after biomaterial exposure presents promising opportunities for the development of methods to identify cellular processes that may be predictive for biomaterial-induced responses in patients.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Interproximal attachment gain: The challenge of periodontal regeneration

The new classification of periodontal diseases recognizes the key role of the interdental clinical attachment for defining the periodontal status and the extent of disease severity. Regenerating interdental clinical attachment not only improves the prognosis of the tooth, but it also lessens the severity of the disease condition. This manuscript provides a state-of-the-art review on surgical reconstructive approaches for treating papillary deficiency associated with soft and hard tissue interproximal defects. Combination therapy of papilla preservation, connective tissue grafting, and coronally advanced flaps may result in regeneration of the intrabony defect coupled with root coverage. Future research highlighted here may have the potential, especially in combination approaches, to repair challenging interproximal soft and hard tissue deficiencies.

Effect of Hyaluronic Acid Filler Injection on the Interdental Papilla in a Mouse Model of Open Gingival Embrasure

The black triangle resulting from interdental papilla (IDP) loss is associated with poor aesthetics and difficulty in pronunciation and food impaction. There is limited knowledge of gingival tissue inflammatory response to hyaluronic acid (HA) filler injection, a minimally invasive IDP reconstruction method. This study aimed to examine the morphological and histological changes in IDP and the inflammatory cytokine localization to the IDP post-HA filler injection using an open gingival embrasure (OGE) mouse model. Mice from the control, sham, and OGE groups were attached with reference, inactive, and activated wires for 5 days, respectively. The degree of IDP loss was determined based on the spring-papilla distance (SPD). Morphological and histological changes in the OGE group injected with phosphate-buffered saline (PBS) or HA fillers were examined on days 2 and 7 post-injection. Immunohistochemical analysis was performed to determine the localization patterns of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, myeloperoxidase (MPO), and Ki67. Five days post-wire attachment, the control and OGE groups exhibited a significantly higher SPD than the sham group (p < 0.0167). The SPD of the HA filler injection group was significantly lower than that of the PBS injection group on days 2, 4, and 7 post-injection (p < 0.05). The IDP of the OGE group was wide and flat. HA filler was stable in the connective tissue underlying the epithelial tissue even on day 7 post-injection. TNF-α, IL-1β, IL-6, MPO, and Ki67 were highly localized to the connective tissue surrounding the filler on day 2, which decreased on day 7 post-injection. Thus, HA filler can safely and successfully reconstruct the IDP in cases of OGE.

Minimally invasive procedures for deficient interdental papillae: A review

OBJECTIVE

Deficient interdental papillae cause a series of problems, including food impaction, phonetic difficulties, and esthetic concerns. The purpose of this article is to provide valid clinical recommendations for clinicians to address these problems in a predictable and less invasive way.

OVERVIEW

Numerous treatments are available for interdental papillae reconstruction, but most of them involve surgery and yield unpredictable outcomes. Minimally invasive treatments have the advantages of being effective, predictable, and involving only slight injury as compared to surgical treatments. We included 66 studies obtained after searching for relevant papers in PubMed and Web of Science. The etiology and classification of deficient interdental papillae are explained and minimally invasive procedures for deficient interdental papillae reconstruction are summarized.

CONCLUSIONS

Minimally invasive procedures are promising ways to reconstruct deficient interdental papillae, and have the advantages of slight pain and rapid recovery. It should be noticed that some of the minimally invasive treatments still require further long-term observation to confirm their efficacy.

CLINICAL SIGNIFICANCE

Familiarity with etiology and classification of deficient interdental papillae can help clinicians to choose the appropriate minimally invasive approach as well as help with case collection to enhance esthetics status in patients with deficient interdental papillae.

Minimizing tissue damage due to filler injection with systemic hyperbaric oxygen therapy

Recently, there is a growing interest of hyperbaric oxygen therapy in many fields of medicine. We had a 43-year-old female patient presented with severe necrosis of the nose, philtrum, and upper lip due to retrograde arterial occlusion after nasolabial fold hyaluronic acid filler injection. Our patient went through 43 sessions of systemic hyperbaric oxygen therapy from December 2, 2017 to January 18, 2018. We administered 2.8 atmosphere absolute (ATA) for 135 minutes in the first session and the remaining sessions consisted of 2.0 ATA for 110 minutes. In reporting this case, we wish to provide a warning regarding the latent risk of filler injections and share our experience about minimizing soft tissue damage in the early stages with systemic hyperbaric oxygen therapy.

Use of different concentrations of hyaluronic acid in interdental papillary deficiency treatment: A clinical study

Background:

In the present era, demand of beauty and esthetics has increased rapidly. Interdental papilla construction, especially in the esthetic zone, is one of the most challenging tasks. Interdental papilla loss might occur due to several reasons as a consequence of periodontal surgery, trauma, and others.

Aim and Objective:

The present study was aimed to prepare economically feasible injectable form of hyaluronic acid (HA) gel in three different concentrations – 1%, 2%, and 5% HA to evaluate its efficacy in the enhancement of deficient interdental papilla (IDP).

Materials and Methods:

A total of 42 sites (mean age range was 29.6–30.6 years) was categorized into three groups; 1% HA group (16 sites), 2% HA group (14 sites), and 5% HA group (12 sites). Total 35 sites were followed up out of 42 in which 2% HA group included only 7 sites. Both maxillary (17 sites) and mandibular (18 sites) sites were included in this study. HA was injected at 2 mm apical to papillary tip at weekly interval for 3 weeks. The IDP augmentation was measured using UNC-15 probe and modified stent at 1, 3, and 6 months. The photographic analysis was done using Image J software.

Results:

On clinical measurement, 5% of HA showed highly significant enhancement (P = 0.001) of 19.2%, 20.6% 18.2% at 1, 3, and 6 months, respectively. On photographic analysis, 5% of HA showed 41%, 42.9%, and 39.8% at 1, 3, and 6 months, respectively. However, intergroup comparison showed nonsignificant improvement.

Conclusion:

This study results suggest that the use of 5% of HA is effective for interdental deficiency treatment with minimal rebound at the end of 6 months. The modified stent for IDP measurement used in this study for the first time in the literature is highly recommended. The photographic analysis using image J Analyzer serves a useful and dependable tool. Further, long-term clinical studies would throw more insight in this regard.

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.

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.