I report a case of a patient with Stage IV Grade C extensive chronic periodontitis who was reluctant to undergo treatment due to fear of dentists.

The patient was a 55-year-old male who visited our clinic with complaints of gingival swelling, bleeding during brushing, and tooth movement of his right upper molar. Clinical examination showed the following: gingival redness and swelling of the gums; bleeding on probing (BOP): 85.3%; periodontal pocket probing depth (PD): over 4 mm in 58.3% and over 6 mm in 7.7% of teeth; O'Leary's plaque control record (PCR): 85.6%. X-rays showed horizontal bone loss in all alveolar bones.

During the initial medical interview, the patient informed us that he had experienced dental trauma in the past and that he did not wish to undergo treatment using infiltration anesthesia. We explained the results of the examination and thoroughly educated the patient about the necessity of treatment and the importance of oral cleaning.

As the treatment progressed, the patient's thoughts about dental treatment changed for the better as he realized the benefits of the treatment, and he became more proactive in participating in the treatment himself, leading to stabilization of his condition, without the need for periodontal surgery.

Severe periodontal inflammation is known to adversely affect the pathogenesis of diabetes mellitus. Herein, we report a case in which we suspected involvement of severe underlying periodontal inflammation in the sudden deterioration of the blood glucose level (HbA1c).

The patient, a 78-year-old man, was admitted to the Division of Kidney, Diabetes and Endocrine Diseases of the University Hospital in March 2021, after his primary care physician reported rapid deterioration of his blood glucose level (HbA1c = 13.8%). The physician from the Diabetes Unit suggested the need to refer the patient for a periodontal examination, and the patient was referred to the Department of Periodontics and Endodontics, Division of Dentistry, the University Hospital. Oral examination at the dental clinic revealed progression of severe periodontitis and the patient was determined as needing comprehensive periodontal treatment intervention at the earliest. He visited our clinic, which was easily accessible from his home, in May 2021, to receive specialized periodontal treatment.

Periodontal examination revealed that the percentage of teeth with a probing pocket depth of greater than 4 mm was 76%, the rate of bleeding on probing was 81%, the plaque control record was 100%, and the periodontal inflamed surface area (PISA) was 3,217 mm². Radiographic findings suggested moderate progression of horizontal bone resorption in both jaws, with resorption extending to the root apex in 37 and 47. The diagnosis was extensive severe chronic periodontitis (stage IV, grade C). Initial periodontal treatment consisted mainly of scaling and root planing with local antimicrobial agents, taking into account the influence of diabetes mellitus on the pathophysiology.

The patient responded very well to the periodontal treatment and his HbA1c level improved to 6.5% (January 2022) with improvement of the periodontal inflammation (PISA: 605 mm² at re-evaluation). We believe that close medical-dental collaboration and early specialized periodontal intervention led to the marked improvement of the blood glucose levels.