Over the years, few attempts have been made to use survival analysis techniques in dental research. Moreover, the use of survival analysis was restricted to a simple method of drawing a survival curve using the Kaplan-Meier technique, but later prognostic factors were included utilizing the Cox Proportional Hazard (CPH) model. More recently, the CPH model has been incorporated with a frailty parameter to account for the correlation of observations within a subject. A recent publication has utilized a subdistribution hazard model with time-dependent covariates. In actual dental practice, a tooth failure could be due to a variety of reasons other than the cause of failure of interest. To have a realistic estimate of the risk of failure for cause i, one should also include the risk of failure due to causes j, j=1(1) n, which could occur prior to cause i. This competing risk scenario has been attempted in the last ten to fifteen years or so to estimate the probability of failure in the presence of competing event(s). Precise estimate of survival (failure) probabilities using competing risk model has implications in the dental cost-effectiveness and cost-utility studies.

The authors have declared no competing interest.

This work was partially supported by a grant from the Department of Diagnosis and Oral Health, University of Louisville School of Dentistry, KY, USA The funders had no role in study design, data collection, analysis, decision to publish, or manuscript preparation.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Michael Geisser Co-chair, IRBMED Alan Sugar Co-chair, IRBMED Robertson Davenport Co-chair, IRBMED Decision: Exempt from ongoing IRB review University of Michigan Medical School Institutional Review Board (IRBMED): Study eResearch ID: HUM00157260; Amendment eResearch ID: Ame0012260; IRB Exemption Determination Date: 4/13/2022; OHRP IRB Registration Number(s): IRB00001999 Study title: Long-term tooth retention after stage and grade assessment-results after more than 10 years of a conservative periodontal treatment regimen in a university setting

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present study are available upon reasonable request to the authors.