## 4 Discussion
### Limitations of the Study  
There are several limitations to note. First, this is a cross-sectional study of vaccination status and the intention to vaccinate, and reasons may change over time. We reported that nearly 35% of parents stated \"undecided\" or \"other/no reason.\" Although we included the option of free-text documentation, there was no additional information provided to allow us to identify other challenges and barriers perceived by parents of unvaccinated dental patients. Second, we analyzed data based on parents' self-reported data of HPV vaccination status with no stratification by the number of doses received. In pediatric dental clinics, providers ask about HPV vaccination status for new and established patients when completing or revising the full medical and dental histories as part of a comprehensive or periodic oral examination. [PERSON] and [PERSON] evaluated the validity and reliability of parents' and providers' reports of teens' HPV vaccination status using data from a National Survey [22]. They concluded that the self-reports are reliable [22]. Because our EHRs are not linked to medical records or the Immunization Tracking system of the state of Texas (ImmTac2), we could not validate the patient responses with the immunization records. Validation of the self-reported vaccination status is recommended [23] and will be possible as EHRs advance toward integrating medical and dental clinical information. Third, data were collected by a diverse group of dental students and residents, supervised by the clinical faculty, and we considered the potential for interviewer, selection, and response biases. Interviewer bias could have happened because of the challenges in calibrating a diverse group of dental providers--students, residents, and faculty members, with different levels of comfort and communication styles. How the question was asked may have influenced the patient's responses. We acknowledge the likelihood of response bias as a dental provider asked the questions, and parents may have felt uncomfortable indicating a reason that could demonstrate a lack of trust in the provider. We also acknowledge that our patient population was recruited at a single academic dental clinic, the study is susceptible to selection bias, and the findings may not be generalizable to pediatric dental populations in other clinical settings or geographic regions.  
Reasons for the unwillingness to receive the vaccine at the dentist may be better evaluated by a separate English and Spanish survey administered at the time of the clinical appointment by a trained research interviewer. Lastly, we did not include the option \"I don't know\" when asking the parent about their child's HPV vaccine status because the interviewer was a dental provider and expected to be prepared to answer questions related to HPV vaccination. We acknowledge this critical limitation. Parents' knowledge of and readiness to accept the HPV vaccine may be shaped by language and cultural beliefs [24]. Cultural stigma surrounding HPV may have influenced the willingness to respond or accept vaccination, and has introduced selection bias in this study population. It is essential to inform the development of tailored, multilingual educational messages, which should be explored in future studies for increased awareness of HPV vaccines and to build trust between patients' families and dental providers.