title: Adverse reaction after hyaluronan injection for minimally invasive papilla volume augmentation. A report on two cases.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Periodontology, Faculty of Odontology, University of Malmö, Malmö, Sweden.|Division of Oral Surgery, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.
authors.forename: Kristina
authors.initials: K
authors.lastname: Bertl
authors.affiliation: Department of Oral Rehabilitation, School of Dentistry, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Klaus
authors.initials: K
authors.lastname: Gotfredsen
authors.affiliation: Department of Oral and Maxillofacial Surgery, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
authors.forename: Simon S
authors.initials: SS
authors.lastname: Jensen
authors.affiliation: Division of Conservative Dentistry and Periodontology, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.
authors.forename: Corinna
authors.initials: C
authors.lastname: Bruckmann
authors.affiliation: Department of Periodontology, Faculty of Odontology, University of Malmö, Malmö, Sweden.
authors.forename: Andreas
authors.identifier: http://orcid.org/0000-0001-8161-3754
authors.initials: A
authors.lastname: Stavropoulos
mesh_terms: D000328:Adult; D003442:Crowns; D019250:Dental Implants, Single-Tooth; D005260:Female; D005881:Gingiva / Q000187:drug effects*; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000009:adverse effects*; D058427:Hygroscopic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D007267:Injections; D008437:Maxilla
chemical_list: D058427:Hygroscopic Agents; D006820:Hyaluronic Acid
keywords: Hyaluronan; adverse effect; filler; livedo reticularis; papilla augmentation; swelling