Abstract: Objective: To analyse the characteristics of clinical trials of photodynamic therapy (PDT) for the treatment of oral diseases registered in ClinicalTrials.gov. Methods: All clinical trials of PDT for the treatment of oral diseases in ClinicalTrials.gov were retrieved and collected with a search timeframe from the establishment to 31 December 2023. The registration title, registration status, registration time, sample size, group leader unit, study implementation site, funding type, disease type, outcome, study type and design, randomised method, blinded method, number of study centres, light source, and photosensitiser of the included clinical trials investigating the treatment of oral diseases were summarised and analysed separately. Results: A total of 133 clinical trials were included, and the main types of oral diseases were periodontitis (36.09%), gingivitis (15.79%), halitosis (6.77%), endodontics diseases (6.77%), peri-implantitis (5.26%), dental caries (5.26%), oral cancer (4.51%), actinic lipitis (3.76%), oral leukoplakia (3.76%), and oral lichen planus (3.76%). The geographic distribution of the group leader units involved in the implementation of clinical trials of PDT for oral diseases was concentrated in five countries, including Brazil (38.35%), the United States (9.77%), China (6.77%), Finland (5.26%), and Saudi Arabia (4.51%), which accounted for 64.66% of all the group leader units. All studies were intervention studies, in which 108 studies (81.20%) were randomised controlled trials (RCT) and 90 RCT (83.33%) were blinding. The maximum sample size was 350 and the minimum was 2, with a median of 40; and 93.98% were single-centre studies. Laser and light-emitting diode (LED) light sources were frequently used in PDT for oral diseases, with 660nm red laser being the main one. Photosensitizers mainly included methylene blue, toluidine blue, 5-aminolevulinic acid, indocyanine green, and curcumin. Conclusion: Periodontitis, gingivitis, halitosis, endodontics diseases, peri-implantitis, dental caries, oral cancer, actinic lipitis, oral leukoplakia, oral lichen planus, and so on, are the hot areas of the clinical research of PDT for oral diseases. The inconsistency of photosensitiser, wavelength, energy density, power density, outcome, observation duration in the current clinical trials of photodynamic therapy for oral diseases is prominent, and a standard treatment method needs to be developed to achieve homogeneity of treatment effects. RCT applying the blind method accounted for a high proportion of studies, the overall design quality was high, and the number of studies was fluctuating, but the imbalance in the number of studies between countries was obvious, with a high proportion of single-center and small-sample-size studies, and further multi-centre and large-sample RCT need to be carried out.

Key words: photodynamic therapy, oral diseases, clinical trials, ClinicalTrials.gov