*3.2. Regression Analysis*

Multiple logistic regressions with postponed dental visits (0 = no, not postponed; 1 = yes, postponed) as outcome measures are displayed in Table 2. Regressions revealed that the likelihood of postponed dental visits due to the COVID-19 pandemic since March 2020 was positively associated with being younger (aged 65 and older, OR: 0.43, 95% CI: 0.22–0.85; compared to individuals 18 to 29 years), and higher affect regarding COVID-19 (OR: 1.36, 95% CI: 1.13–1.64). Furthermore, there was a marginal significant positive association between postponed dental visits and big cities (compared to small towns, OR: 1.53, 95% CI: 0.99–2.34). The remaining variables were not significantly associated with the outcome measure.

The results of further analysis with multinomial logistic regression (with "Yes, postponed dental visits" as the base outcome) are displayed in Supplementary Table S1. Findings remained comparable to our findings using multiple logistic regressions.

**Table 2.** Determinants of postponed dental visits (0 = no, not postponed; 1 = yes, postponed) due to the COVID-19 pandemic since March 2020. Findings of multiple logistic regressions.



**Table 2.** *Cont*.

Odds ratios are reported; 95% confidence intervals in parentheses; \*\*\* *p* < 0.001, \*\* *p* < 0.01, \* *p* < 0.05, + *p* < 0.10.

#### **4. Discussion**

Based on nationally representative cross-sectional data, the aim of this study was to clarify the frequency of postponed dental visits due to the COVID-19 pandemic and to determine its associated factors. Furthermore, the type of postponed dental visits was displayed (check-up/regular dental examination; pain/dental complaints; planned therapy). Based on individuals who postponed dental visits or did not attend as planned, it should be emphasized that approximately 43% of individuals postponed dental visits, and a significant amount postponed dental visits despite "pain/dental complaints". Our study extends previous knowledge focusing on actual use of dental services in early 2020 [10] or modeled use of dental services [9].

Our study showed that more than one out of five individuals postponed a dental visit due to the COVID-19 pandemic between March and July 2020, particularly check-ups and regular dental examination. Predominantly individuals aged 30 to 49 years (29.1%) postponed dental visits. Regressions revealed that the likelihood of postponed dental visits was positively associated with being younger and higher affect regarding COVID-19.

Younger individuals are at an increased risk of postponing dental visits because they have to fulfill family and job obligations concurrently (e.g., compared to older adults, 65 years and above). The burden increased during the COVID-19 pandemic due to, e.g., school closings and the requirement to work from home. Furthermore, the link between increased affect regarding COVID-19 and postponed dental visits appears plausible. Previous studies have shown a link between dental fear and avoidance of dental visits [17]. It should be noted that (negative) affect is commonly associated with fear or anxiety-related factors [18]. Since there was a lack of studies quantifying the reasons for postponed dental visits, it was difficult to compare our results with studies published in past years.

Postponing dental visits can have serious consequences for oral health. For example, it could result in caries lesions and periodontitis which, in turn, could increase the likelihood of tooth loos [5] or dental pain [19]. This is important, since the COVID-19 pandemic can markedly affect oral health [20–22]. Even in the light of the effect of different recall intervals [23], our current findings are therefore of great importance.

This is the first study showing the frequency and correlates of postponed dental visits in Germany during the COVID-19 pandemic. Another strength is that nationally representative data were used. Additionally, the type of postponed dental visits was recorded. One limitation is its cross-sectional design with the acknowledged limitations. Future research is needed to examine postponed dental visits among individuals aged 75 years and older. Moreover, future research is required to explicitly clarify whether the postponed dental visits were postponed by the patient or by the clinician. Furthermore, upcoming studies should include factors such as dental anxiety.

## **5. Conclusions**

In conclusion, data showed that more than one out of five individuals postponed a dental visit—particularly check-ups and regular dental examination—due to the COVID-19 pandemic between March and July 2020. Some determinants of these postponed visits have been identified, namely age and affect regarding COVID-19. The findings may help identify and address individuals at risk for deterioration of oral health due to postponed dental visits.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/2227-9 032/9/1/50/s1, Table S1: Determinants of postponed dental visits due to the COVID-19 pandemic since March 2020. Findings of multiple multinomial logistic regressions (base outcome: Postponed dental visits).

**Author Contributions:** Conceptualization, A.H., F.D.B. and H.-H.K.; formal analysis, A.H.; methodology, A.H.; supervision, H.-H.K.; writing—original draft, A.H.; Writing—review and editing, A.H., F.D.B., L.H., B.K. and H.-H.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by DFG, grant number 3970/11-1; further funding via BZgA, RKI, ZPID, University of Erfurt (no funding numbers). The funders had no role in study design, data collection, interpretation, or the decision to submit the work for publication.

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board of University of Erfurt (#202000302).

**Informed Consent Statement:** Informed consent was obtained from all individual participants included in the study.

**Data Availability Statement:** Data are not publicly available but interested parties may contact the authors for more information. The data are not publicly available due to ethical restrictions.

**Acknowledgments:** Germany's COVID-19 Snapshot Monitoring (COSMO) is a joint project of the University of Erfurt (Cornelia Betsch [PI], Lars Korn, Philipp Sprengholz, Philipp Schmid, Lisa Felgendreff, Sarah (RKI; Lothar H. Wieler, Patrick Schmich), the Federal Centre for Health Education (BZgA; Eitze), the Robert Koch Institute Heidrun Thaiss, Freia De Bock), the Leibniz

Centre for Psychological Information and Documentation (ZPID; Michael Bosnjak), the Science Media Center (SMC; Volker Stollorz), the Bernhard Nocht Institute for Tropical Medicine (BNITM; Michael Ramharter), and the Yale Institute for Global Health (Saad Omer).

**Conflicts of Interest:** The authors declare no conflict of interests.
