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Updated: May 1, 2026

Adjunctive Diode Laser Therapy and Probiotic Lactobacillus Therapy in the Treatment of Periodontitis and Peri-Implant Disease
Published on: May 9, 2022
Photodynamic effects on human periodontal-related cells in vitro
Jing Qiao1, Shiying Wang1, Yi Wen1
1Department of Periodontology, Peking University School and Hospital of Stomatology, The First Outpatient Center, Xishenku Avenue 37, Xicheng District, Beijing 100034, China.
Background:
Photodynamic therapy (PDT) may be especially effective in combination with conventional periodontal therapy by its antimicrobial activities, but PDT may also exhibit other mechanisms that promote the healing of periodontal tissue. Therefore, the purpose of the present study was to evaluate the photodynamic effect of PDT on human periodontal ligament cells (hPDLCs) and human gingival fibroblasts (hFBs) in vitro and other possible mechanisms to promote periodontal healing.
Methods:
The proliferation of hPDLCs and hFBs was assessed by MTT assay. Cell attachment on cementum slices of hPDLCs and hFBs was evaluated by MTT assay. Type I collagen synthesis of hPDLCs and hFBs was analyzed using enzyme linked immunosorbent assay. The alkaline phosphatase (ALP) activity in hPDLCs was measured by p-nitrophenyl phosphate substrate reactions.
Results:
PDT treatment induced constant time-dependent growth of hPDLCs and hFBs at 24h, 72h and 6 days (P<0.05). PDT treatment also promoted time-dependent hPDLCs and hFBs attachment on the cementum slices at 24h, 72h and 6 days compared to the controlled cells (P<0.05). Type I collagen synthesis of hPDLCs and hFBs was markedly stimulated by PDT in a time-dependent manner (P<0.05). Likewise, a significant increase in the specific ALP activity in hPDLCs was observed (P<0.05).
Conclusions:
The findings of this study indicate that PDT exhibited no cytotoxicity to hPDLCs or hFBs. Instead, it stimulated proliferation, attachment and collagen synthesis of hPDLCs and hFBs and ALP activity of hPDLCs. These effects might signal similar PDT activity on periodontal-related cells, and expanding the scope of its potential therapeutic utilization is very appealing.

