Currently, there is a common, unanimous agreement that oral health is correlated with the QoL. [2–4, 15, 16] The OHIP-14 questionnaire, which Polish version was validated by our team prior is considered to be the tool of choice for evaluation of the OHRQoL among the population.[14] The tools used, together with the clinical examination and the questionnaire assessing the socio-economic status of the patients, allowed for a analysis and determination of factors and relationship affecting quality of life, as well as for finding limitations and problematic aspects. Another great advantage of our study was the possibility of reaching out to a significant population of elderly people with a view to promoting oral health and advising them on preventive measures and treatment options corresponding to their medical needs. The validation of the OHIP-14 questionnaire, gathering of data on oral health of Polish elderly population, as well as the chance to examine half a thousand citizens of Wrocław, one of the biggest city in Poland clearly indicates the purposefulness of the conducted research and its contribution in science, particularly because similar data regarding health condition and the quality of life of the elderly is barely available.
The present study findings indicated that all domains of OHIP-14 were positively correlated with DMFT and the number of extracted teeth. A study conducted in Spain in the same age group showed a slightly higher OHIP-14 value and it revealed a correlation with the number of missing teeth [17]. Similarly, in residents of Saudi Arabia aged over 60, the OHIP-14 value was similarly correlated with DMFT. [18] In the UK population in the same age group, OHIP-14 values were found to be significantly lower [19], contrary to Iranian residents and a group of the Swedish elderly, where OHIP-14 values were found to be significantly higher than in the present study. [20] Inukai et al. also reported a significantly higher mean total OHIP-14 scores. It was found that higher chewing ability was correlated with lower OHIP-14 summary scores, which indicated better OHRQoL. The correlation between perceived chewing ability and OHRQoL was not substantially affected by age and number of teeth, but by gender, schooling years, treatment demand and denture status.[21]. Koistinen et al. also found that the factors associated with poor OHRQoL included female sex, oral problems and perception of poor physical, psychological and oral health. Women were more likely to report poor OHRQoL than men. [22] In the present study, however, the OHIP-14 value showed no differences related to the participants' gender
The analysis of the present study results using linear regression showed that the number of missing teeth allowed to predict values in all domains of the OHIP-14 scale. Unfortunately, although there are advances in conservative dental treatment, the loss of many natural teeth still occurs in the elderly. It should be emphasised that tooth loss is not an inevitable result of the normal ageing process, but a consequence of untreated or ineffectively treated caries, periodontal disease, traumatic injury, and thus it is a negative indicator of both the patient's health-seeking behaviour and the effectiveness of dental care. According to Jain et al.'s study conducted among the residents of two major cities in India, both age and tooth loss were correlated, however, they had different effects on the OHRQoL. Tooth loss, which was correlated with the increase in age, was associated with a negative impact on the perception of the QoL, whereas the increase in age of the participants had less impact on the perception of QoL.[23]
As much as 32.8% of xerostomia cases were reported among the Polish elderly participants. Xerostomia correlated with functional limitation and psychological disability. Paredes-Rodríguez et al. also observed a significant correlation between a higher level of xerostomia and a poorer QoL. [24] According to their study results, however, QoL was not related to the number of remaining teeth nor the number of ingested drugs.
The maintenance and reconstruction of tooth structure are of great importance in terms of maintaining proper chewing function. The loss of natural teeth prevents the proper functioning of the masticatory organ and it necessitates the use of prosthetic restorations. In the present study, the use of removable dentures increased functional limitation, physical disability, social disability, and handicap. Parea et al. focused on the overall satisfaction of edentulous patients treated with conventional dentures. The obtained data enabled the conclusion that the use of conventional complete dentures adversely affected OHRQoL of elderly patients, mainly in the case of lower dentures that required repair and replacement, with removable complete dentures as antagonists. [25]
The implementation of the term OHRQoL created new perspectives for the estimation of the extent to which oral health or oral diseases affect a patient's life in general. It changed the perception of the problem from a dental-oriented perspective to a biopsychosocial-dental, thus patient-centred, approach. In the study by Brennan at el.,[15] both the objective (income) and the subjective socioeconomic status were associated with OHIP scores. Mean OHIP scores were higher for those born overseas and speaking a language other than English, as well as for smokers and those brushing their teeth less frequently. In the present study, the socioeconomic status did not affect the OHIP score. Living alone resulted in higher functional limitation, psychological discomfort, physical disability and social disability.
McGrath et al. found that the elderly perceived oral health as a significant QoL factor in a variety of ways. The majority of them (73%) considered it important for physical, social and psychological QoL. It was most frequently perceived as the impact affecting eating function and comfort. [26] It should be emphasised that both general and oral health were strongly associated with the elderly, while the general health of seniors with more severe health problems had a significant effect on their oral health – participants with worse health status suffered more oral health problems.[3] According to the present study, the experience of pain exacerbates when there is an increase in the number of comorbidities and taken medications.
Changes in the oral cavity, which accompany the ageing process, affect all the oral cavity structures. Although overall health status deteriorates with age, there are many ways to manage it so that a person can continue to lead an independent life. Hence, active ageing is about ageing in good health, active participation in society, fulfilment in professional life, and independence in daily life. The assessment of OHRQoL has multiple important clinical implications. It represents a multidimensional construct that includes the patient's subjective assessment of their own health, functional and emotional well-being, treatment-related expectations and satisfaction as well as general well-being.
Several limitations have to be taken into consideration in a discussion concerning the results of this study. Firstly, this study was conducted using a self-reported questionnaire to report data such as OHIP-14 which could lead to identification bias. However, it was proved by some studies that the questionnaire can be used as a valid and reliable method. Secondly, the use of survey data did not allow us to explain temporal relationships nor to show inferences on causality. Thirdly, when analysing the obtained results, it is essential to bear in mind a possible self-selection error of the study participants – those who joined the study were concerned about their dental problems or they were aware of those problems and were looking for help. Moreover, some persons may have refused to participate in the study due to dental fear. Another interfering factor was related to the use of exclusion criteria. The study was limited by the exclusion of patients with coexisting systemic diseases in whom pocket probing leading to transient bacteremia might have posed a risk for their overall health status. That exclusion criterion involved many patients in this age group. Finally, the exclusion of patients with a mental disorder might have constituted another interfering factor.