Hyaluronan Injections Are Ineffective to Reconstruct Missing Papilla Volume at Single Implants in the Anterior Maxilla : an RCT with 6 M Follow-Up

• Background: There is an increasing demand from patients for highly esthetic outcomes of implant restorations. Open gingival embrasures – also called ‘black triangles’ – may occur after tooth replacement with an implant due to loss of interproximal papilla volume. Black triangles are perceived as unaesthetic by most patients, especially when these are located in the maxillary anterior region. In a case series, Becker et al. (2010) described promising results with a simple, minimally invasive, non-surgical technique for augmenting the interproximal gingival papilla volume and thus reducing the black triangles; the technique involved hyaluronan (HY) injection in the deficient papilla. HY is an important component of the extracellular matrix and responsible for tissue resilience and volume. HY is used in dermatology as injectable dermal filler for wrinkle reduction. So far, no controlled clinical study on the potential of HY injection to augment the volume of the interproximal papilla is available. Aim/Hypothesis: The present randomized controlled clinical trial aimed to assess the effect of HY injection into the interproximal mucosal tissue to reconstruct missing papilla volume next to a single implant restoration in the anterior maxilla. Material and Methods: Patients with a deficient papilla next to an implant in the anterior maxilla were randomly assigned to receive twice an injection of HY (test group) or saline solution (control group). The following parameters were recorded prior to- (baseline) and 3, and 6 months after injection: modified papilla index score, distance between the papilla tip and contact point, and standard clinical periodontal parameters. The deficient area (i.e. black triangle) was evaluated on pictures and aesthetic appearance and pain level were recorded on a visual analogue scale. Mucosal volume changes were assessed after 3 months by intraoral scans and differences in the bone level before/after treatment were radiographically assessed after 6 months. A sample size calculation based on the data from Becker et al. with a significance level alpha of 0.05 and a power of 0.8 resulted in a sample size of 16 patients; due to a possible dropout rate (i.e. 20%), 20 patients per group were planned. Due to normal distribution the independent t-test was used for comparisons between control and test group and the dependent t-test for comparisons between baseline and 3 and 6 months data. Differences at baseline between the groups regarding gender, gingival phenotype, and tissue texture and color distribution were tested with Fisher's exact test. Results: Due to a preliminary analysis of 10 patients, which showed no difference between the groups and specifically no change of the modified papilla index score, the patient recruitment was stopped after 22 patients (11/group). Except for bleeding on probing, no significant differences between groups or over time within groups were observed for any of the clinical parameters; bleeding on probing was at baseline significantly lower in the test compared to the control group. Modified papilla index score was 2 for all patients at all time-points. Mean distance between the papilla tip and contact point ranged between 1.8 and 2.3 mm without significant differences between groups or over time within groups. Similarly, insignificant differences between groups were detected regarding the deficient area, gingival volume changes, bone level, aesthetic appearance and pain level during injection; only discomfort within the first week after injection lasted significantly longer in the test group (P = 0.03). Conclusions and clinical implications: The present randomized controlled clinical trial showed that HY injection into deficient interproximal papillae tissue between a tooth and an implant in the upper anterior did not have any relevant effect in terms of reconstructing the missing papilla volume.

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MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Odontologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Dentistry (hsv//eng)

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