Interplay of pandemic and seasonal parameters in dental emergency service

Until January 2^nd, 2021, there have been more than 1,755,351 confirmed cases of COVID-19 and more than 33,960 associated deaths in Germany [1]; until April 1^st 2022 21,357,039 confirmed cases were registered [2].

The public COVID-19 infection prevention led to different governmentally regulated measures to slow down the rate of infection. Those regulations included several lockdown measures in public life; pandemic-related restrictions had an impact on the daily lives of all citizens in Germany. All healthcare facilities were distinctly hampered by the COVID-19 pandemic around the world; additionally, dentistry as a potential aerosol-forming sector was of particular interest [3]. The specific and unspecific governmental measures may very likely have resulted in a COVID-19 pandemic quantitative and qualitative impact on dental health behavior such as emergency visits.

The dental emergency service is regulated by the dental boards in Germany and is conducted by private practices and university hospitals. The relative indications for emergency treatment do not represent an emergency in an actual sense and, objectively, no urgent treatment is required [4]. Nonetheless, since patients are usually not able to distinguish, out of hours treatment can be indicated even in relative emergencies.

The absolute emergencies correspond to the indications, which imply an urgent treatment.

The aim of our study was to investigate the hitherto barely known influence of a pandemic situation and, specifically, its wave-formed process on visiting behavior and emergency characteristics in dental emergency service. We intended to analyze the changes in patient behavior focusing on the first two waves on virus outbreak taking into account annually rhythmic events of the year such as vacations and seasons.. The insights gained from this study may provide information about the demands for healthcare services in future similar situations. Furthermore, this study can help to assess the general challenges of the dental emergency outpatient service.

Our study includes a total of 11,219 dental emergency patients over a period of three years (Table 1).

In the years 2018 and 2019 that were not affected by COVID-19 in Germany, 4,214 (2018) and 4,097 (2019) patients presented at the emergency service. In 2020, 2,908 patients visited the emergency service (Table 1). Thus, the total count of cases decreased by more than 25%. An inverse relationship between the 7-day-incidence and the emergency visits was observed.

The share of absolute emergencies in 2020 was higher than in the years before (OR = 1.19, p < 0.0001; Table 1).

This effect was pronounced especially during times of higher incidence rates of COVID-19.

Looking at the distribution month by month, there is a strong contrast to the previous years in March 2020 (OR = 1.62, p = 0.002) and in December 2020 (OR = 1.59, p = 0.003) (Table 2).

Men attended the emergency service marginally more often, with a male to female ratio of 1.16:1 over all three years (Tables 3 and 4).

There was almost no difference between the average age in 2018, 2019 and 2020 (36.64–36.88 years). The number of patients visiting the emergency service was highest in age group 21–40 years (Tables 5 and 6).

Our study revealed an interplay of pandemic and seasonal parameters and number of visits: relative and absolute emergencies decreased during COVID-19. This effect was considerably more pronounced regarding the relative emergencies, while the number of patients with absolute emergencies remains rather constant, even in times of pandemic-related contact restrictions. Variations were also found in different age groups. The share of absolute emergencies, for example, increased significantly in the elderly age group (61–120 years old) in phases of high COVID-19 incidence.

Therefore, our study provides an overview of the situation in dental emergency service before and during the COVID-19 pandemic in a dental unit of a university hospital. The comparison of the pandemic waves with each other and with previous years' periods are clear strengths and special features of our study.

Our data show that the total count of cases decreased by more than 25% in 2020. We found an approximately inverse dependency of 7-day-incidence of COVID-19 and number of visits (Fig. 1). This effect has also been found in other studies regarding dental and non-dental emergencies during the pandemic [5‐7]. Other investigators found the absence of patients in the pandemic being triggered by the fear of infection [8, 9]. Therefore, this fear might have contributed to the decrease in emergency visits during the pandemic in our study.

The inverse dependency of the COVID-19 incidence and the number of visits was not observed in all studies. In another investigation, 724 patients were treated in a dental emergency service of a university hospital in April 2020, whereas only 160 patients received dental care in 2019 during the same time period and at the same affiliation [10]. It can be speculated that the under- and over-utilizations, respectively, strongly depend on the political measures taken in the health sector of the respective region. A study that compared three periods (pre-lockdown, lockdown, post-lockdown) in a university hospital demonstrated that the daily number of patients increased during the lockdown [11].

In our study, emergencies were subdivided into absolute and relative emergencies as suggested by a large European dental society. This dichotomous classification exists since 1994 and is simple and unambiguous. It clearly assigns diagnoses to grades of urgency.

Unfortunately, there is no widely agreed classification system for dental emergencies with regard to urgency of the required treatment.

In the study by Famà et al. patients were subdivided according to the Glasgow Coma Scale. The patients were divided into three groups according to the urgency of treatment [12, 13]. Another study also used a three-level classification system. However, this study included maxillofacial patients, whereas our study focused exclusively on dental outpatients [14, 15]. In previous studies on this topic, cases were often divided into urgent and non-urgent or not further classified [7, 11].

In the study by Famà et al., as for the group of most urgency, the number of visits did not differ between pre-pandemic and pandemic phases [12]. This is consistent with our finding that the number of absolute emergencies was less affected during 2020. The least-urgent cases of this study decreased like the relative emergencies in our study [12]. In the study by Guo et al. a decrease of relative emergencies by more than 50% was noted, which again supports our observation [7]. In that study, a similar volume of patients (12,416) were included, as in our investigation. However, our study did not only compare periods of low and high incidence during the pandemic as occurred in the study by Guo et al., but also analyzed waves of the COVID-19 pandemic and corresponding periods of previous years. Despite the use of different classification systems, both Guo et al. and our study found an inverse dependency between the number of visits and COVID-19 incidence [7].

As shown, the share of relative emergencies in a similar setting is about 75% [16]. This matches our findings of approximately 72% for the non-COVID-19 years (Table 1). In 2020, proportionally more absolute dental emergencies than in 2018 and 2019 were documented, while the relative emergencies decreased compared to previous years.

Nevertheless, it should be taken into account that the political measures were different among countries and regions. On some continents, for example, curfews lasted for weeks, whereas in several European countries, curfews were limited to the nighttime and shorter periods.

Like our workgroup, Lentge et al. compared the COVID-19 situation with the two previous years (2020 with 2018/19) in a cohort under similar political conditions. In contrast, the observation period lasted four weeks only. Here, craniomaxillofacial surgery patients were included only and the number of patients in 2020 was significantly lower compared to both years before [5].

In our study, the proportion of absolute emergencies was highest in the age group 0–20 years, i.e. twice as high as compared to some other age groups (Tables 5 and 6), which might have been caused by the increased likelihood of traumatic events in in childhood and youth [17‐19].

Patients older than 60 years who only suffered from relative emergencies rather tended to avoid visiting the emergency service during 2020 (Fig. 3, Tables 5 and 6). This concurs with the results by Howley et al., who have shown a reduction of emergency visits by elderly people during COVID-19. Overall, a decrease in emergency visits by 16% was observed in patients of 70 years and older [20]. In our study, unlike the relative emergencies, the absolute emergencies decreased to a lesser extent in the elderly age group. In the younger patients and in the total cohort, there was a rather similar reduction in absolute and relative emergencies (Figs. 1, 2, 3). Possibly, fear of infection in an emergency office may vary among age groups.

In non-COVID-19-years and during the pandemic, slightly more men presented the dental emergency service, which is in agreement with the findings by other investigators [14, 21]. The pandemic showed no significant effect on gender distribution.

Our results show a clear overall increase of patient numbers during the Easter and Christmas holidays (Fig. 1). This concurs with the findings of another study that investigated emergency services during Christmas holidays under non-pandemic circumstances [22]. This result could be linked to the fact that many private dental offices were closed for vacation during the periods mentioned. In addition, the rise of emergency visits could have been caused by an increase in leisure time activities and thus a higher risk for injuries [18, 23].

The reduction of total emergency visits in our study by 41.06% during the first wave and by 31.86% during the second wave (Fig. 5) is consistent with the study by Cordova et al. who reported a decrease in a plastic surgery emergency services during the pandemic waves [24]. Similarly, in an ophthalmologic emergency service, a reduction of 53% was noted [25]. However, although both studies also compared COVID-19 versus non-COVID-19 phases, they did not distinguish between different COVID-19 waves of the pandemic. In the second wave, absolute emergencies were less reduced than in the first wave as our study revealed.

The number of patients presenting after traumatic events decreased by approximately two thirds less in the second wave compared to the first wave. Possibly, people were more likely to avoid outdoor activities and sports during the first wave, whereas such activities might have played a greater role again during the second wave. That recreational activities are associated with dental trauma has been reported before [18, 23].

In a pandemic situation, dental emergency facilities can expect fewer patients overall, but relatively more absolute emergencies. It can be assumed that there is an acclimatization effect regarding the wave comparison, as visits increased less in the second wave compared to the first wave. Patients older than 60 years who only suffered from relative emergencies rather tended to avoid visiting the emergency service during 2020.

Since the COVID-19 pandemic is still ongoing and other pandemic situations could follow, this study helps implement public health strategies by prediction of patient behavior regarding dental emergencies.