Chronic erosive gingivitis is a syndrome (CEGS) that combines severe gingival inflammation and gingival erosion. The term "desquamative gingivitis" is often used in the literature to define chronic erosive gingivitis. However, this definition is inappropriate because the pathophysiological process at the origin of this gingival disease does not induce a desquamation but rather a loss of gingival substance, namely erosion, concerned wholly or in part of the gingival epithelium. In most clinical situations, chronic erosive gingivitis is an oral manifestation of a general disease with immune dysfunction. The most frequently described diseases are gingival lichen and autoimmune bullous diseases (AIBD). In 2018, as part of a monocentric study, we were the first to detail an original papillary gingival biopsy protocol, non-iatrogenic, perfectly suited to the anatomopathological examinations necessary for the diagnosis of AIBD gingival expression. The CEGS early detection by odontologists avoid delayed diagnosis and allows patients to be referred to the closest AIBD reference center.

Hypothesis/Objective A bicentric study was conducted, to evaluate the clinical relevance of this protocol, including the differential diagnosis of the CEGS. Research was supplemented by carrying out a systematic review of the literature to compare the contributive capacity diagnostic of the papillary biopsy technique with other gingival sample methods (attached gingival tissue, mucosa).

Method A retrospective bicentric observational study was conducted from October 2011 to July 2019, in two departments of oral medicine of two public hospitals in Paris (University Hospital - Bretonneau in Paris and Henri Mondor in Créteil; France). These two departments are specialized in the diagnosis and management of oral pathology; that of the Henri Mondor hospital is an AIBD reference center.

The literature review was developed in accordance with PRISMA recommendations. It was conducted on Pubmed - MEDLINE and Cochrane Oral Health Group and included all existing publications from 1935 until August 2019. A manual search of publications from the unpublished literature was also conducted.

Inclusion Criteria:

• Patients referred on an outpatient basis by the physician or the dental surgeon, suffering from an acute erosive gingivitis, regardless of age and general health.

Exclusion Criteria:

• Patients referred on an outpatient basis by the physician or the dental surgeon, with a histological examination and immunofluorescence (DIF) already done previously, and patient under corticosteroid therapy which is skewing the immunofluorescence (DIF) data.

Over the study period we were able to study 101 files, but the investigator's final sample of patients included 100 adults. In first-line, 2 papillary gum biopsies were performed simultaneously for 48 of them (48%), 1 for histological examination and 1 for immunohistochemistry. For 47 other patients (47%) only 1 biopsy was performed for histological examination and for the remaining 5 patients (5%) only 1 biopsy for immunofluorescence (DIF).