The OHIP-EDENT B&H Questionnaire: Translation and Psychometric Properties in Treatment of Acrylic Complete Denture Wearers

Objectives. The OHIP-EDENT (the OHIP-EDENT B&H) translated from the original English language version was assessed in complete denture wearers before and after new denture manufacture and adjustments. Materials and Methods. A total of 117 acrylic complete denture wearers participated. The convergent validity was assessed by calculating point bi-serial correlations between the OHIP-EDENT Summary scores and the quality old dentures. Responsiveness was assessed by comparison of Summary score before (old dentures) and after adjustments of new dentures. Results. Cronbach alpha coecient was 0.80 in the patients with their old dentures and 0.76 in same patients after receiving new dentures and all adjustments provided. Convergent validity coecients varied between 0.491 and 0.548. Responsiveness was conrmed by signi ﬁ cantly lower scores of the OHIP-EDENT B&H after new denture delivery and adjustments, both for Summary scores (p=0.027), as well as for the domains of functional limitation (p=0.02), psychological discomfort (p=0.01), physical pain (p=0.003), and handicap (p=0.04). Conclusions. The translated version of the OHIP-EDENT B&H showed good psychometric properties. Clinical Relevance. Clinical signicance of the application of the OHIP-EDENT B&H questionnaire is in the reection of the achieved success in the therapy by acrylic complete dentures after corrections of teeth and denture surfaces at recalls.


Introduction
Quality of life (QOL) is a multi-dimensional construct which implies an individual's perception of the state of one's life 1 . Quality of life is an important concept in the eld of health and medicine 2 . There is an increasing emphasis on the signi cance of investigating life quality in determining the effects of diseases and therapies on one's health-state. Today, quality of life as a healthcare index is very important for all health professionals, also for dentists 3,4 . Understanding QOL is important for improving diagnostic and therapy of patients 4 . Problems revealed by patients' self-reported QOL may lead to modi cations and improvement in health-care. QOL is also important for medical decision-making because QOL is a predictor of treatment success and is therefore of prognostic importance. This prognostic ability suggests that there is a need for routine assessment of QOL in clinical trials, as well as clinical daily practice.
According to World Health Organization (WHO) data, more than 40% of older people in Albania, Bosnia & Herzegovina, Bulgaria, Canada, Finland, Malaysia, and the UK suffer from total tooth loss 5 . Therefore, it is important for clinicians to know the bene ts that oral health rehabilitations and different prosthodontic rehabilitation options can offer to patients. For this purpose, speci c tools which measure impact on oral health related quality of life (OHRQol) have been developed [6][7][8][9][10][11] . One of such tools is the Questionnaires: Oral Health Impact Pro le -EDENT (OHIP-EDENT), developed originally in the English language environment, aimed for measurement of OHRQoL in edentulous population.
The aim of the study was to assess psychometric properties of the translated version of the original OHIP-EDENT questionnaire [12][13][14] into the Bosnian language (the OHIP-EDENT B&H) during treatment with a new pair of acrylic complete dentures in edentulous patients.

Materials And Methods
The study included 117 edentulous patients. All patients consulted Department of Prosthodontics at the Health Centre of the Faculty of Pharmacy and Health (FZF) in Travnik, Federation of Bosnia and Herzegovina 15 . During the rst visit, patients were examined by a specialist of prosthodontic, who assessed the status of the existing acrylic complete dentures. The patients were interviewed. All of the patients' responses were recorded using the paper-based OHIP-EDENT B&H questionnaire. The ID number was also assigned. Subsequently, a new set of complete dentures was made and delivered to each patient. Each patient was re-examined by a specialist of prosthodontic one month after the new complete acrylic dentures had been delivered and completely adjusted. The Bosnian language version of the OHIP-EDENT questionnaire (OHIP-EDENT B&H) was then completed again and patients used the same ID numbers.
The original English version of the OHIP-19 was adapted through the two translations carried out independently by two dentists with an advanced level of English language knowledge. They discussed and produced a consensual nal Bosnian version of the OHIP-EDENT questionnaire 12 (the OHIP-EDENT B&H) which comprised 19 questions related to removable denture wearers' quality of life. Answers were rated on the Likert's scale (0-4), with zero representing no problems and 4 the highest discomfort.
The third dentist, who worked in the USA for 20 years, was back-translated the questionnaire. One lay person whose mother tongue was English language read both versions and stated that there were no semantic differences between the two versions.
A specialist of prosthodontics evaluated old patients' dentures by assessing each of the following parameters: old dentures in general, vertical dimension of occlusion, occlusal contacts, as well as denture's retention and stability. Old dentures were assessed using dichotomous values: insu cient quality or su cient quality. Vertical dimension of occlusion was assessed taking into consideration patients' free way space when speaking, appearance of the lower third of the face and existence of angular cheilitis. Occlusal contacts were registered using a thin articulating paper (40 µm, Bausch, Nashua, USA). Denture retention and stability were assessed by trying to remove a denture from a denture bearing area and by exerting light pressure by ngers upon denture's incisors and upon denture premolars trying to dislodge a denture 16 . One specialist of prosthodontics made all assessments of old dentures, although in a pilot study high inter-rater agreement was con rmed between the two specialists of prosthodontics who assessed same 30 patients. The Kappa value was 0.83. However, only one of them evaluated all patients' old dentures.
Sample size calculation was conducted using the freely available G*Power statistical program v. 3.1.9.2 and was based on the following assumptions: Wilcoxon signed-rank test, power of 90%, alpha = 0.05, two tails, normal distribution, OHIP mean summary scores 32.4 (SD = 19.0) in baseline group vs. 27.9 (SD = 17.5) in after treatment group, interclass correlation coe cient 0.805, effect size 0.391786 based on previously published data 17 . Based on these assumptions, the required sample size would be total 74 patients. Therefore, because we assumed 20% overall attrition rate, we decided to increase the sample size by 20% to minimal total 90 patients.

Results
A total of 117 completely edentulous patients participated. All of them had existing old complete dentures. Thirty-six (30.34%) were men, with an average age of 72.70 ± 9.04 years; 81 were women, with an average age of 73.10 ± 6.73 years.
The internal consistency was con rmed by high Cronbach's alpha coe cient. The Cronbach alpha coe cient was calculated twice in the same patients, rst before intervention (patients with old complete dentures) (Cronbach alpha = 0.80) and then again after new complete denture delivery and adjustments (Cronbach alpha = 0.76).
The instrument's convergent validity was con rmed by a signi cant correlation coe cient between the OHIP EDENT B&H Summary Scores and a quality of old complete dentures (assessed by a specialist of Prosthodontics) ( Table 1). Psychological discomfort and Handicap of the OHIP-EDENT B&H after new dentures delivery and adjustments were signi cantly lower than summary scores of the same patients with their old dentures (Table 2). Summary scores signi cantly decreased, presenting good responsiveness to the therapy ( Table 2). Related samples t-test; *-p < 0.05; **-p < 0.01; SD-standard deviation; N-number Frequency of participants' responses (almost always, sometimes, never) with old and new dentures is presented in the Fig. 1 and frequency of responses (almost always, sometimes, never) of each domain of the questionnaire is presented in the Fig. 2. After the new denture delivery and adjustments the patients' response rate 'never' increased 3.1%; the frequency of the patients' response 'sometimes' increased 10.2%; and the frequency of the response 'almost always' decreased by 13.3%.

Discussion
In the Bosnian language-speaking area, different questionnaires which assess OHRQoL have already been used 18,19 . Problems with inadequate removable dentures can affect social activities and emotional life, and problems with complete dentures may increase over time [20][21][22] . Therefore, it is particularly important to re-assess OHRQoL in edentulous patients rehabilitated with removable dentures for a prolonged period of time. Assessment of OHRQoL is also important to evaluate effects of a therapy, either after rehabilitation with new dentures, or after old denture adaptation (rebasing, adjustments, etc.), or after dental implant placement to support a removable denture. The OHIP-EDENT questionnaire has been specially developed to assess edentulous patients. The Bosnian language questionnaire did not exist, and this study aimed to assess psychometric properties of the OHIP-EDENT B&H version of the questionnaire.
In the last decade one study showed good psychometric properties of the Serbian language OHIP14 questionnaire, which it is a language similar to Bosnian language 23 .
In the municipality of the town of Travnik (Federation of Bosnia and Herzegovina) a high frequency of fully or partially edentulous population exist 24 and developing of an adequate instrument to examine their OHRQoL would be very important 22,24−26 . Therefore the OHIP-EDENT was translated into the Bosnian language, and psychometric properties of the questionnaire were evaluated.
Both, the Cronbach alpha coe cients before and after dental interventions in the examined cohort of patients were similar and showed good internal consistency of the instrument [27][28][29][30] . The values of the alpha Cronbach coe cients in this study are also comparable with other authors who adapted the OHIP-EDENT or the OHIP-14 Questionnaires in Jordan, Montenegro, Greece, Italy Chile, Poland, Brazil and Croatia [30][31][32][33][34][35][36][37] .
Convergent validity also showed signi cant positive correlation between a quality of old complete dentures and the OHIP-EDENT summary scores (0.41 to 0.54), which was not very high. However, it may be due to the fact that patients may often be over-adapted to their old dentures 39 . About 71% of the elderly patients more than 65 years have some adaptation problems wearing of new complete dentures 40 . Therefore, older patients require more adjustment visits and also exhibit a poorer denture acceptance than younger patient 41 .
Responsiveness of the OHIP-EDENT B&H questionnaire was con rmed by signi cant improvement of patients' OHRQoL after new complete denture manufacture and adjustments by signi cantly decreased scores.
Oral Health Impact Pro le for Edentulous Patients (OHIP-EDENT), with a higher score meaning poor quality of life, is also used in the latest clinical studies [42][43][44][45][46][47][48] , and thus justifying the great importance of this work and our idea for translation and psychometric properties on the Bosnian language. Therefore, translation and psychometric properties of scales into different languages provides a better clinical outcome for patients using these scales on the maternal language.

Conclusions
Many clinical studies used the OHIP-EDENT questionnaire, which points out the importance of the development of the OHIP-EDENT B&H for assessment of clinical outcomes and comparison of the results worldwide. The OHIP-EDENT B&H questionnaire can be considered an effective instrument for measuring the outcome of treatment and other interventions in the edentulous population.

Declarations
Con ict of Interest: All authors declare that any of authors has no con ict of interest. Funding: This study was not supported by any funds or grants.
Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This study has Ethic approval no 03-67-1/14 issued by FZF of University of Travnik.
Informed consent: For this type of study informed consent was obtained from all individual participants included in this study.