The main finding of the study was that the oral health parameters such as visible plaque and BOE scores significantly improved during 5 week stay at neurorehabilitation setting but the proportion of sites with BOP and frequency of tooth brushing over time (5-week stay) did not reach statistical significance. These findings demonstrate that although there was an improvement in the oral health status in hospitalized individuals, it was not substantiated, indicating a need for further development in oral care program.
A significant reduction in the amount of dental plaque was observed over time. Plaque is a biofilm comprised of diverse community of microorganisms which is formed regularly on the tooth surface and can be maintained by proper tooth brushing and flossing 1,16,17. Individuals with less severe ABI are usually admitted to the regional ward at HNRC instead of highly-specialized ward due to their better motor and cognitive functions, which makes them more co-operative then severely affected individuals with ABI 18. It was also evident from the mixed regression analysis that individuals admitted to the ‘regional ward’, showed an strong association in reduction of plaque compare to highly-specialized ward 19. Interestingly, the proportion of plaque was also reduced in individuals with ‘moderate’ periodontitis and with an increased proportion of calculus and BOP, indicating that there are also other factors such as host-immune response 5, which were not taken into account in this study, that might have influenced BOP.
Gingival bleeding (BOP) is an acute reversible inflammatory condition that occurs as a response to plaque accumulation on the periodontal tissues 20. In general, good oral hygiene practices are sufficient to control and reduce gingival bleeding 17,21, which was also shown in the current study with strong association between plaque and BOP (Table 3C). However, despite the significant plaque reduction, proportion of sites with gingival inflammation (BOP) did not reduce in the same individuals over the study period. It is also important to discuss that the SD values of BOP were probably quite higher as few individuals had a very low BOP, while some (especially those with periodontitis) had high BOP. Such a finding suggests that factors other than plaque might play a role in the onset and progression of gingival inflammation. It has been shown that a more exacerbated and rapid immune response, acute hospitalization and cognitive and systematic complications are linked to a higher neutrophilic activity, which is able to mount an immediate response when exposed to plaque 22,23. Interestingly, our findings demonstrated that BOP decreased over time in individuals who showed an improvement in their ‘cognitive’ function, indicating reduction in confusion and agitation leading to increased cooperation with oral care, which very well correlates with previous research 5. It has been shown that BOP is closely associated with ‘severe’ periodontitis, which in addition to an already existing cognitive impairment, may contribute to other chronic conditions that share a common biological background to ABI 5,24. Assuming that such an exacerbated immune response is not restricted to the oral cavity, this may interfere with other inflammatory processes, especially in a hospital setting and in the presence of other comorbidities, explaining partially our findings 5. On the other hand, the proportion of sites with BOP increased over time among patients with both ‘moderate’ and ‘severe’ periodontitis, despite the increase in tooth brushing frequency over the same period. This finding indicates that the oral health status in these patients were poor and tooth brushing alone may not be enough to tackle oral health problems. Despite the efforts made by nurses to maintain oral hygiene, there was still deterioration of the inflammatory periodontal condition 1. This suggests the need for involvement of dental personnel in hospitals for providing adequate oral care to ABI patients 3.
Calculus, defined as hard deposit around the gingiva as a result of long-term plaque accumulation, showed no significant improvement over time. It is important to highlight that calculus does not indicate disease, but it makes oral hygiene more difficult to maintain as well as works as a plaque-retaining factor 25. Even though the removal of calculus is not possible without professional dental assistance, it is possible to maintain proper oral hygiene by preventing calculus formation. Such a finding supports the idea that chronic oral changes require professional help from dental personnel as well as changes in socio-behavioral factors for the improvement of oral health 20. Our findings also revealed that individuals with eating difficulty and those who developed pneumonia during hospitalization had an increase in the proportion of sites with dental calculus. One may speculate whether the combination of dental calculus and eating difficulties may influence the onset of pneumonia. A recent study on patients with ABI has shown a robust association between periodontitis and debilitating conditions like dysphagia, dependency on a feeding tube, which is a major concern, as they lead to pneumonia 5. Although our study does not allow us to disentangle the causal relationship between these conditions, our overall findings suggest the need for increased focus on oral care especially for ABI individuals with conditions like eating difficulties and severe cognitive disturbances.
Interestingly, BOE scores decreased in individuals with higher scores of ‘moderate’ periodontitis. As discussed, ‘moderate’ periodontitis originates essentially from neglected oral hygiene, so does most the BOE domains 3,5,21,26. Thus, the combined effect of plaque reduction and increased frequency of oral hygiene can explain this association. It should be noted that, although BOE is a simple and easy to use tool in hospital settings, especially in intensive care units, its usefulness is questioned in ABI patients and therefore, the BOE results may be carefully interpreted 2,3. This is because the instrument seems not to reflect the real clinical conditions of patients with ABI, thus, affecting the treatment plan. Further, it has been shown that ‘ageing’ patients have more compromised function than young individuals, making them more vulnerable to dysphagia and unable to perform and maintain good oral hygiene procedures 3,5.
A recent survey conducted among 157 oral caregivers at HNRC showed that the majority of oral caregivers were aware of the existing ‘Danish National Clinical Guidelines for Oral Care’ 19. However, a significant number of oral care providers did not follow the guidelines systematically, expressing it as an ineffective, time-consuming, and difficult to follow 14. Professionals were aware that patients with eating difficulties have challenges and different requirements 14 and on top cognitive and motor deficits adds an extra challenge to maintain the oral hygiene 5. In addition, there is always a professional dilemma to maintain oral hygiene standard whilst respecting patient’s autonomy once they refuse for the oral hygiene care, even if it is required. Therefore, all these factors should be considered while formulating and designing oral care training and guidelines to improve oral care in a neurorehabilitation setting.
Methodological Considerations
The current study sample originates from a single hospital setting, and therefore, our findings may have limited external validity. However, it is worth mentioning that this hospital is a reference center for the treatment of ABI patients and receives patients from most regions of Denmark. In addition, limited sample size and 30% lost to follow-up might have reduced the analytical power, as can be noted by borderline P-values. Future studies with large samples originating from several centers are needed. Another limitation of the study was short follow-up time, given the chronicity of the most common oral diseases, i.e., dental caries and periodontitis. However, treatment of these conditions demands the involvement of dental personnel with appropriate armamentarium, which was not within the scope of the study. As our purpose was to observe the effect of hospitalization on oral health, we decided to evaluate conditions such as the proportion of dental plaque and of BOP, as those parameters can rapidly change. We also need to be aware that few patients were excluded due to extreme fatigue, agitation, motor-cognitive deficits etc., leaving us with no opportunity for clinical examination, which might be a bias in representing the entire oral health status.