Patients diagnosed with stage III or IV periodontitis during routine visits at the department of periodontology will undergo a validated questionnaire to understand the impact of the disease on their quality of life.

The purpose of this study is to evaluate the impact of stage III and stage IV periodontitis on the quality of life of patients and to evaluate the differences of the results between the two forms of the disease.

Patients who presents to our periodontology department for routine follow-up visits, if diagnosed with one of these two forms of periodontitis, will be asked if they intend to answer a short questionnaire with the intent to understand how the disease affects their daily activities and interactions.

The questionnaire that will be used is the short-form Oral Health Impact Profile (OHIP-14), which consists of 14 questions each one formulated in the following way: "How often (impact item) because of problems with your teeth, mouth, or dentures?" The impact items belong to seven different impact domains: (a) functional limitations, (b) physical pain, (c) psychological discomfort, (d) physical disability, (e) psychological disability, (f) social disability, and (g) handicap. Each question could be answered with a score from 0 to 4 corresponding to: 0 = never, 1 = hardly ever, 2 = occasionally, 3 = fairly often, and 4 = very often.

The impact items are:

Had trouble in pronouncing words Felt that sense of taste had worsened Had painful aching in your mouth Found it uncomfortable when eating food Been feeling self-conscious Have you felt tense Diet has been unsatisfactory Had to interrupt meals Found it difficult to relax Been a bit embarrassed Been irritable with other people Had difficulty during usual jobs Felt that life less satisfying Been totally unable to function Overall mean scores as well as for each question and for each impact domain will be calculated and compared with two ways ANOVA statistical analysis.

Inclusion Criteria:

• Patients affected by periodontitis stage III
• Patients affected by periodontitis stage IV

Exclusion Criteria:

• Patients affected by periodontitis stage I
• Patients affected by periodontitis stage II

Patients of any age affected by periodontitis stage III or stage IV willing to answer a questionnaire about their quality of life

Individual participant data will be shared in a publication after the end of the study

Data will be submitted for publication right after the analysis of the outcomes