2.4. Questionnaires (QLQ-C30, OHIP G49)

At baseline, before MRONJ treatment (T0), 12 weeks (T1), 6 months (T3) and 1 year after treatment (T3), all patients completed the OHIP-G14 and QLQ-C30 questionnaires.

The Oral Health Impact Profile 14 (OHIP-G14) [21,22] is a short-form oral health impact profile based on the longer OHIP-G49 questionnaire [23,24]. In the original OHIP-G49 questionnaire, participants were asked how frequently they had a certain symptom the week before. It consists of 49 items and covers seven domains, namely Functional Limitation (9 items), Physical Pain (9 items), Psychological Discomfort (5 items), Physical Disability (9 items), Psychological Disability (6 items), Social Disability (5 items) and Handicap (6 items). For each of the 49 OHIP questions, subjects rate on an ordinal scale (0 “never”, 1 “hardly ever”, 2 “occasionally”, 3 “fairly often”, 4 “very often”) how frequently they have experienced a specific oral health impact, with a lower index score indicating a better OHRQoL. The most widely used OHIP version nevertheless is the G14 version with 14 items, 2 items for each of the above-mentioned seven domains [22,25]. Recently, John et al. reclassified the OHRQoL. They advise only to compute the domain scores for Physical Disability, Physical Pain, Psychological Discomfort and Handicap scores. These scores should be renamed to Oral Function, Oralfacial Pain, Orofacial Appearance and Psychosocial Impact scores, respectively [25]. The sum of the scores for each item was used to construct the so-called OHIP index score. Lower index scores indicate a better evaluation of OHRQoL. The scores of the items pertaining to each of the domains were added to determine the scores for each domain.

The second questionnaire used was the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 [26]. It is a questionnaire consisting of 30 items resulting in five functional scales (physical, role, cognitive, emotional and social), three symptom scales (fatigue, pain and nausea and vomiting) and a global health and quality-of-life scale. Further, it contains single items assessing common symptoms of patients suffering from cancer, these are dyspnea, appetite loss, sleep disturbance, constipation, diarrhea and financial impact [26]. Since a detailed explanation of the calculation of the QLQ-C30 scores is beyond the scope of this paper, we refer to the corresponding scoring manual [27].