Background: The fear of pain is closely linked with chronic pain and the resultant impairment of daily life. It has been reported to have a strong correlation with dental anxiety, making its assessment crucial in dental practice. The present study aimed to develop a Japanese version of the Fear of Pain Questionnaire-III (FPQ-III), an international rating scale, to evaluate psychological characteristics and investigate its association with dental anxiety and gender differences. Methods: After forward and backward translation and review, the Japanese version of the FPQ-III was administered to 400 internet monitors, and 100 of them were re-evaluated after a month. Convergent validity was assessed in relation to catastrophic thoughts of dental anxiety and pain, while discriminant validity was evaluated concerning the correlations between anxiety and depression. Confirmatory factor analysis was used to examine the factorial validity of the FPQ-III and a shortened version of the FPQ-9. Item response theory was applied to estimate the discriminative power of each item and draw a test information curve. Structural equation modeling was used to investigate the relationship between pain anxiety and dental anxiety and the gender differences in the model. Results: Data from 400 participants (200 women [50.0%, mean 44.9 ± 14.5 years]) were analyzed. Total scores on the FPQ-III showed good internal validity, intra-examiner reliability, and discriminant validity, indicating convergent validity. Confirmatory factor analysis results supported a three-factor structure, and the FPQ-9 showed a good fit. Discrimination was high, except for two items related to severe pain. Test information curves demonstrated that the FPQ-III and FPQ-9 were more accurate for latent characteristic values between -2 SD and +2 SD. Anxiety about medical pain fully mediated the relationship between fears of minor pain and dental anxiety. No gender differences were observed in this construct, and the factor means for anxiety about severe pain were significantly higher for women than for men. Conclusion: The Japanese versions of the FPQ-III and FPQ-9 demonstrated high reliability and validity for measuring the Fear of Pain in this target population, with high accuracy for a wide range of latent characteristics. Pain anxiety was deemed an endogenous factor that was linked to dental anxiety and common to both men and women.

The authors have declared no competing interest.

Awardee: O.M. The name of the fund: JSPS KAKENHI: Grant-in-Aid for Early-Career ScientistsGrant Number: 20K18817. Funder: Japan Society for the Promotion of Science URL: https://www.jsps.go.jp/english/ The funder did not play any role in the study.

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:

The study was approved by the Ethical Committee of Fukuoka Dental College (approval number: 586). Informed consent was not obtained for this survey as it was an anonymous research. An explanatory document was presented prior to the survey and only those who consented to the survey were transferred to the main survey.

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 relevant data are within the manuscript and its Supporting Information files.