Introduction

The reorganisation of a highly structured healthcare system must address various aspects of patient care. At the onset of the COVID-19 pandemic in early 2020, hospitalisation rates and bed occupancy, particularly in intensive care units (ICUs), emerged as critical indicators of potential overburdening of the public health system.

On 27 January 2020, the first case of COVID-19 in Germany was confirmed in Munich, with case numbers increasing exponentially in subsequent weeks.1,2 As infections spread across the country, the Robert-Koch Institute implemented a pandemic emergency plan that included a nationwide lockdown starting on 22 March 2020.2,3

During that period, dental practices in Germany faced significant challenges. Initially, dental offices were deprioritised in the distribution of personal protective equipment, such as FFP2/3 masks, limiting their ability to operate safely.2 Additionally, staff shortages, often due to COVID-19 infections, forced many practices to close temporarily.4 As a result, the number of elective and non-emergency dental consultations not driven by pain has decreased dramatically.4 While infection rates in Europe decreased during the summer of 2020, cases surged again in autumn, leading to another partial lockdown on 28 October 2020. This second lockdown further strained healthcare facilities, with clinics unable to meet the demand for urgent treatments.5 Hospital admissions for dental emergencies in Germany initially returned to pre-pandemic levels during the summer of 2020 but declined again in the winter and spring of 2020/21.4,6 Nationwide, overall inpatient hospital admissions fell by approximately one-third in the first eight weeks after the initial lockdown was announced.7

Further studies reported a 50% reduction in dental emergency cases during this period, whereas hospital admissions for certain dental emergencies increased by 4%, with no significant change in the proportion of high-risk patients.8 In Germany, most high-risk patients continue to seek dental emergency care,8 and in Switzerland, an increase in dental abscess cases was observed during the first lockdown period (February-June 2020).9

Aims

In summary, the pandemic resulted in the centralisation of healthcare services - a phenomenon that parallels the objectives of the upcoming German healthcare reform.

The primary aim of this retrospective single-centre study was to evaluate the impact of the COVID-19 pandemic on a major metropolitan hospital in Germany. The analysis focused on metrics such as length of hospitalisation, ICU admissions and treatment outcomes in 2020 compared with 2019. For non-COVID-19 patients, the study sought to determine whether their treatment was restricted or compromised due to the strain on hospital resources.

Additionally, this study provides context for the German hospital reform passed on 12 December 2024. The reform aims to categorise hospitals into three levels (I-III) to improve the quality of care while reducing bureaucratic inefficiencies and the economisation of the healthcare system.9,10 Under this new system, small, local hospitals are designated basic-level facilities and face cuts in financial resources, staff and equipment. Departments handling complex cases, such as oncology and polytrauma, are centralised in higher-level hospitals, such as those in metropolitan areas or university hospitals.9,10

Relevance to dentistry and future outlook

In light of these changes, local dental offices are expected to play a greater role in preventive care. The organisation of oral healthcare services in Germany is structured around the principle of accessibility, with a significant emphasis on preventive measures to reduce the need for complex and costly treatments. The majority of dental care is delivered through private practices, where general practitioners provide preventive routine services, such as yearly routine check-ups, cleanings, fillings and early interventions. These services are predominantly covered under statutory health insurance (Gesetzliche Krankenversicherung [GKV]) for the general population.

However, while preventive oral care is broadly accessible, more specialised treatments often require additional payments or private insurance coverage. In Germany, oral care is freely available to everyone, with certain procedures necessitating out-of-pocket expenses or supplementary private insurance. This tiered system is designed to balance universal access with the option for more individualised care for those with higher income or supplementary insurance (e.g., for higher-quality fillings/root canals, more aesthetically pleasing materials for crowns/bridges). Specialised care for more complex conditions is offered by dental specialists and in larger centres or hospitals. The GKV covers basic dental services for most individuals, but more advanced treatments often require additional patient contributions. This structure ensures that most of the population has access to dental care while also incentivising preventive measures.

Considering the ongoing changes in the German health system, particularly the hospital reform and its potential impact on the availability of specialised services in smaller or rural hospitals, dental practices are expected to assume a more prominent role in early intervention and preventive oral care. The impending retirement of many dental professionals from the baby boomer generation further emphasises the need to optimise the infrastructure of dental practices to handle an increased workload. While the number of practising dentists in Germany has slightly increased annually, this trend is projected to reverse as the baby boomer generation retires in the coming years. Concurrently, the number of ambulatory healthcare centres continues to rise.11,12

Severe dental infections, such as abscesses, often require immediate intervention and may necessitate hospitalisation. The proposed hospital reform raises questions about the potential impact on medical treatment, particularly when such cases can be managed only at higher-level hospitals. With a decreasing number of dental offices and dentists, the results of this study offer valuable insights into how the German healthcare system may evolve under conditions analogous to those experienced during the COVID-19 pandemic.

Materials and methods

This retrospective cohort study was conducted as a single-centre analysis focusing on patients with a primary diagnosis of head and neck abscesses of dental origin. All included patients were admitted for in-house surgical treatment for these abscesses at the Department of Oral and Maxillofacial Surgery, Technische Universität München, Munich, Germany. The recruitment period spanned two years, from 1 January 2019 to 31 December 2020.

Patients were eligible for inclusion if their primary diagnosis was a head and neck abscess originating from a dental cause. Patients with abscesses not of dental origin, such as those caused by medication-related osteonecrosis of the jaw or bisphosphonate-related osteonecrosis of the jaw, as well as abscesses listed as secondary diagnoses, were excluded from the analysis.

Variables

The primary outcome variables were as follows:

  • Total length of hospitalisation (LOS)

  • Length of stay in the ICU.

The year of admission served as the predictor variable, dividing the cohort into two groups:

  • Group A - patients admitted in 2019

  • Group B - patients admitted in 2020.

The secondary analysis included the following covariates:

  • Demographic variables - age, sex and number of underlying diseases

  • Diagnostic parameters - abscess type and anatomical location

  • Perioperative variables - symptoms presented at initial consultation (e.g., difficulties swallowing, shortness of breath, pre-admission antibiotic treatment)

  • Operative parameters - number of surgical procedures performed and timing of abscess cause removal (simultaneous or secondary tooth extraction/treatment)

  • Post-operative outcomes - complications such as prolonged intubation, tracheostomy and interdisciplinary consultations.

Ethics approval and consent

An ethical statement for the retrospective study was granted on 7 December 2022 by the head of the Ethical Committee of the Technical University of Munich, with the retrospective nature of the study (Approval No. 2022-641-S-KH) and all the procedures being performed part of routine care. Obtaining consent was not required for this retrospective study.

Data collection

Data, including physician notes, medical imaging and surgical reports, were extracted retrospectively from both digital and manual patient records. Patient cases were initially identified via the International Classification of Disease codes 12.20-12.29. Files fitting the exclusion criteria were subsequently removed from the dataset.

Statistical analysis

Descriptive data analysis and statistical testing were conducted via SPSS software (IBM, Version 29). Nominal variables were analysed for associations via chi-square tests or Fisher's exact tests. Quantitative data were compared between groups via the Mann-Whitney U test for non-normally distributed data or the t test for normally distributed data.

Correlation analyses were performed to assess relationships between continuous variables, employing Pearson's correlation coefficient for parametric data and Spearman's rank correlation coefficient for non-parametric data. All the statistical tests were two-sided, with a significance threshold set at p = 0.05.

Data processing and visualisation

Data analysis was conducted in collaboration with the Institute for AI and Computer Science in Medicine at Technische Universität München. All figures were generated via SPSS. The dataset used in this study is provided in the online Supplementary Information.

Results

Bivariate analyses of the covariates versus predictor variables (year 2019 versus year 2020)

In total, 200 patients were included in this study: 93 patients in Group A (year 2019) and 107 patients in Group B (year 2020). While the sex distribution was relatively balanced in 2020, a significantly greater proportion of male patients were admitted to the hospital in 2019 (p = 0.004). The mean age was comparable in both groups, ranging between 43-45 years.

A significant difference was observed regarding the type of abscess (p = 0.003). In 2020, there was a notable increase in abscesses involving multiple spaces (10.4%), whereas no such cases were reported in 2019. Additionally, the percentage of patients presenting with shortness of breath (3.2% in 2019 to 6.5% in 2020), as well as the proportion of patients receiving premature antibiotic treatment from local dentists before hospitalisation (4.3% in 2019 to 8.4% in 2020), increased. The need for a third surgical operation markedly decreased in 2020 (7.5% in 2019 to 0.9% in 2020). Similarly, the timing of dental focus removal differed significantly between the groups (p <0.001), with an increased tendency to postpone removal until after hospitalisation in 2020. This trend coincided with reductions in tracheostomy rates (5.4% to 1.9%) and consultation with other medical departments (15.1% to 8.4%).

Bivariate associations between primary predictor and primary outcome variables

A comparison of total LOS and ICU LOS between 2019-2020 is presented in Table 1. While no significant difference was found for total LOS (p = 0.962), averaging at 5.2 days in Group A and 5.7 days in Group B, ICU LOS was significantly shorter in 2020 (p = 0.022). The mean ICU LOS was 13.7 days in 2019 compared to 3.3 days in 2020 (Table 1).

Table 1 Bivariate association between primary predictor and primary outcome variable
Full size table

Bivariate analyses of the covariates versus primary outcome variates

The primary outcome variables in this study were total LOS and ICU LOS.

Total LOS

When examining total LOS against other covariates, ICU admission was significantly associated with total LOS in both groups (p <0.001). However, only in 2019 was ICU LOS significantly linked to total LOS (p <0.001), with a mean ICU LOS of 13.7 days versus 3.3 days in 2020 (Table 1).

Further analysis revealed statistically significant associations in 2019 between total LOS and the type of abscess (p = 0.044). In 2020, premature antibiotic treatment was significantly linked to total LOS (p = 0.014).

The duration of hospitalisation showed significant correlations with intubation (Group A: p <0.001; Group B: p = 0.007), tracheostomy (Group A: p <0.001; Group B: p = 0.023) and consultations with other departments (Group A: p = 0.013; Group B: p = 0.006).

ICU LOS

Six patients in Group A and seven patients in Group B (all male) were admitted to the ICU during their hospital stay. In 2020, one patient required two ICU admissions during the same hospitalisation. The mean age of patients on ICU was 41.7 years in 2019 and 54.4 years in 2020. The mean total LOS for ICU patients was 20.1 days in Group A and 13.9 days in Group B. Only in 2019 was there a statistically significant association between ICU LOS and total LOS (p <0.001). Additionally, in Group A, the number of underlying diseases correlated significantly to ICU LOS (p = 0.044), whereas no such relationship was observed in Group B (p = 0.285).

All ICU patients in both groups had received premature antibiotic treatment before hospitalisation. Notably, the percentage of ICU patients presenting with shortness of breath at initial consultation increased from 16.7% in 2019 to 85.7% in 2020. The number of tracheostomies performed decreased significantly between the two years (66.7% in 2019 to 28.6% in 2020). Both groups exhibited significant correlations between ICU LOS and tracheostomy (Group A: p = 0.042; Group B: p = 0.032). However, only in 2019 did ICU LOS significantly correlate with consultations with other medical departments about pain while swallowing at their initial admission to hospital; no significant association of this variable with ICU LOS could be detected for Group B (Group A: p = 0.021; Group B: p = 0.877).

Discussion

Hospitalisation, ICU admission and the impact of healthcare reforms

One of the primary findings of this study is the significantly shorter ICU stay observed in 2020 than in 2019, despite a comparable total LOS between the two years. A plausible explanation for this difference is the uncertainty surrounding the COVID-19 pandemic during its early stages. Hospitals reserved ICU beds for COVID-19 patients, leading to earlier transfers of non-COVID patients, such as those with abscesses, to general wards once they were stable. Additionally, the reassignment of medical staff from elective units to COVID-19 wards resulted in staffing shortages in ICUs, reducing ICU admissions.13

These findings are particularly relevant in the context of the ongoing German hospital reform, which aims to restructure the healthcare system by concentrating specialised care in larger centres and reducing the number of smaller hospitals, especially in rural areas. The observed shift in ICU utilisation during the pandemic underscores the need for more efficient resource allocation and early intervention strategies to prevent unnecessary hospitalisations.

Increased responsibility for primary care providers

As smaller hospitals close or reduce their services, the burden of initial patient management will increasingly fall on primary care providers, including dentists, necessitating a stronger integration of outpatient and inpatient care. They will take on more responsibility for managing a wider range of dental issues. Dentists will need to collaborate more with general practitioners and hospital teams to manage complex cases, especially those linked to systemic conditions, like diabetes and cardiovascular diseases.14 This could increase the workload of dental practices, particularly in rural areas with limited access to specialised care. In light of the German hospital reform, which emphasises reducing inpatient admissions and optimising resource allocation, stronger collaboration between dental care providers and hospitals will be necessary to ensure efficient patient management. Strengthening referral networks and enabling dentists to manage complex infections at an earlier stage could prevent unnecessary ICU admissions, reducing both healthcare costs and patient risk.

Financial constraints and budget cuts

The economic impact of shorter ICU stays was also evident in this study, as the reduction in intensive care utilisation led to substantial cost savings in 2020. This aligns with one of the core objectives of the German hospital reform: cost efficiency through improved patient management and streamlined care pathways. If early dental interventions can reduce ICU admissions and prevent hospital overcrowding, they should be actively incorporated into future healthcare policies. Strengthening primary dental care could alleviate the strain on emergency departments and ensure that hospital resources are used more effectively, which is a key aspect of the reform's push toward specialised care in fewer but better-equipped hospitals. The reintroduction of budgeting through the GKV-FinStG (Health Insurance Financial Stabilization Act) may limit spending on dental care, particularly for preventive and non-urgent treatments like periodontitis therapy.15 Over time, tight budgets could reduce the scope of dental services, particularly for patients with chronic conditions requiring long-term management. Financial pressure to reduce healthcare costs may shift focus away from preventive care, potentially increasing the burden of dental diseases, such as abscesses.

Workforce challenges, demographic shifts and health equity

The ongoing demographic shift, with many dentists nearing retirement, will exacerbate workforce shortages, particularly in rural areas.16 Fewer young professionals are entering the field and many older dentists are expected to retire soon. This could reduce access to dental care, especially in underserved regions, and may also contribute to difficulties in maintaining a stable dental workforce in rural and smaller urban settings. Patients in those areas may face increased barriers to accessing dental care.14 The reduction in smaller practices or service closures could disproportionately affect vulnerable populations, including older patients, low-income individuals and those living in remote regions.14 This may exacerbate healthcare disparities, making it harder for certain groups to access timely and affordable dental treatment, leading to greater reliance on emergency care.

Technological integration and workforce adaptation

Digitalisation in healthcare, as part of the hospital reform, could benefit dental care through tools such as electronic health records, teledentistry and artificial intelligence (AI)-assisted diagnostics. These advancements could streamline administrative processes, improve patient management, and facilitate better collaboration between dental professionals and other healthcare providers.17 Additionally, dental education may need to evolve to prepare professionals for these new integrated, technology-driven care models, ensuring they are equipped to handle a broader range of responsibilities in the reformed healthcare landscape.

Symptoms, treatment and patient experiences during the pandemic

Challenges in accessing dental care and increased psychological stress

Many patients avoided dental visits due to fears of contracting COVID-19 in healthcare settings.18 The pandemic exacerbated psychological stress, especially among patients with dental anxiety.19 Many dental emergencies worsened during lockdowns, which could have been mitigated by earlier intervention.20 This delay in care was particularly noticeable in patients with chronic conditions, like periodontitis, or those experiencing dental abscesses, who waited longer to seek treatment. Moreover, the increase in cases involving abscesses that affected multiple spaces in 2020 supports the hypothesis of delayed intervention and worsening disease severity with this study.

This is further supported by the rise in patients presenting with severe symptoms, such as shortness of breath and pain while swallowing, which correlated with higher ICU admission rates. Another study from a German hospital in Mainz reinforces this finding, reporting a 22% decline in patient numbers in the dental and maxillofacial emergency service during the pandemic in 2020.6 Simultaneously, the number of severe emergencies and hospital admissions increased, suggesting that delayed treatment-seeking contributed to worsened patient conditions.6 This was also the case for patients of the hospital in Hannover, Germany, indicating that the COVID-19 pandemic significantly influenced emergency visits in oral and maxillofacial surgery, leading to a noticeable decline in patient presentations.21 Particularly, fewer patients with worsened conditions sought emergency care for dental-related issues, suggesting increased hesitation to visit hospitals during the pandemic.21

Teledentistry as a partial solution

Teledentistry emerged as a useful tool for managing non-urgent dental issues during the pandemic. Virtual consultations helped alleviate concerns about virus exposure, though in-person care was still necessary for emergency cases.22,23

The doubling of patients who received oral antibiotic treatment before hospital admission in 2020 may reflect a shift in practice by local dentists during the pandemic to slow the progression of infections and reduce hospitalisation needs.

Disruption of routine preventive care

Routine preventive care, such as cleanings and check-ups, was disrupted during the pandemic, leading to a decline in both oral and mental health.24

Financial strain and healthcare burdens

Economic downturns made dental care less affordable for many patients, leading them to rely on local charities or social programmes for support.25

Emergency care and overwhelmed services

The pandemic resulted in increased reliance on emergency care for dental issues such as abscesses that could have been prevented with routine care. Patients who accessed emergency services faced significant delays due to overwhelmed demand.6 This study also revealed a higher frequency of postponed infection treatments in 2020, with more cases being delegated to local dentists. This shift highlights the importance of a well-structured primary care system that can handle such cases before they escalate into medical emergencies.

Conclusion

This study highlights the significant impact of dental abscesses on hospitalisation and ICU utilisation, emphasising the need for timely intervention and preventive care. These findings suggest that early antibiotic treatment and better coordination between primary dental care and hospitals can reduce the severity of cases requiring ICU admissions.

The observed reductions in ICU stays during 2020 reflect both healthcare system adaptations during the pandemic and the economic benefits of early intervention, aligning with the goals of the German hospital reform. As the reform progresses, ensuring adequate resources for primary dental care and improving referral pathways will be critical to prevent severe infections from escalating into costly ICU cases.

Moving forward, enhancing preventive dental care, integrating outpatient and hospital services, and optimising resource allocation will be essential to achieving a more efficient, sustainable and patient-centred healthcare system in Germany.

This study's findings point to the importance of early dental interventions, such as oral antibiotic treatment, in preventing dental abscesses from escalating to the point of requiring hospitalisation. The marked increase in the number of patients receiving antibiotics before hospital admission in 2020 suggests that local dentists took a more proactive approach in treating infections early, potentially preventing the need for ICU admission. Additionally, the study noted that patients may have delayed seeking care due to fears of contracting COVID-19, further emphasising the role of dentists in managing dental health to avoid complications that require hospitalisation.

In light of ongoing healthcare reforms in Germany, particularly those aiming to streamline hospital services and improve the efficiency of specialised care in metropolitan areas, ensuring the availability of adequate dental care in all regions becomes even more critical. As smaller hospitals in rural areas may be phased out, local dentists must play a central role in managing dental health to prevent conditions, such as abscesses, from escalating. This requires a coordinated approach where dental care providers are empowered and adequately resourced to handle complex cases early on, preventing the need for more intensive hospital-based interventions.

Ultimately, improving preventive care and early intervention through better coordination between dentists and hospitals can alleviate strain on the healthcare system, reduce ICU admissions and lower overall healthcare costs. By reinforcing the importance of dental health and investing in early treatment, the healthcare system can be made more efficient, sustainable and capable of managing both routine and emergency care in the long run.

Finally, technological advancements, such as teledentistry and AI-assisted diagnostics, offer promising solutions to improve patient management and strengthen collaboration among healthcare providers. Moving forward, the integration of these innovations within the healthcare system will be crucial in mitigating the pressures created by both the pandemic and ongoing healthcare reforms.