Multiple PDT sessions with chlorin-e6 and LL-37 loaded-nanoemulsion provide limited benefits to periodontitis in rats.

BACKGROUND: The combination of photodynamic therapy (PDT) and LL-37 has never been tested in an animal study and our research team background suggests this strategy might be a promising alternative to intensify periodontitis resolution. This study aimed to assess the effects of multiple sessions of PDT with chlorin-e6 conjugated to the antimicrobial peptide LL-37 loaded nanoemulsion, as adjunctive therapy in experimental periodontitis in rats. METHODS: Experimental periodontitis was induced in 81 rats. After disease establishment, animals were assigned to three groups: SRP (scaling and root planning); SRP + 1PDT, SRP followed by a single PDT session; SRP + 4PDT (n=27), SRP followed by four PDT sessions at 0, 24, 48 and 72h after SRP. Animals were subjected to euthanasia at 7, 14 and 28 days, and samples were submitted to osteoclast quantification, immunological and microtomography analysis. RESULTS: All treatments resulted in significant periodontal improvements and there was no significant difference between the groups in both local inflammatory response and healing process. Minimal adjunctive effects could be found for the combined therapy in terms of cytokine levels (IL-1ß and IL-10), with no statistical significance. However, the number of TRAP-positive osteoclasts per mm of alveolar bone linear surface for the group treated with PDT sessions was significantly lower than those treated with SRP only. CONCLUSIONS: Multiple PDT sessions with chlorin-e6 and LL-37 nanoemulsion as an adjunct to scaling and root planning reduced the presence of osteoclast in the local site but did not contribute towards bone regeneration and IL-1ß and IL-10 levels.

Influence of infiltrant application time on the reduction of opaqueness of proximal enamel caries.

INTRODUCTION: Infiltrant resins were developed to hamper carious lesion progression and mask the whitish appearance of first evidence of caries. OBJECTIVE: This study aimed at testing the hypothesis that a long application time of resin infiltrant in proximal enamel caries improves esthetic outcome compared to the commercially recommended time. MATERIALS AND METHODS: Twenty teeth with uncavitated inactive proximal white enamel caries lesions (selected by two calibrated examiners; inter-examiner κ = 0.87) were divided into two groups (experimental and control group; n = 10) that agreed regarding lesion surface area. Lesions were infiltrated following the protocol recommended by the manufacturer (two applications, 3 min application first and another 1 min application later; control) and by the protocol tested in this study (one application of 30 min; experimental). Enamel opaqueness (esthetic outcome) was measured by a calibrated examiner (intra-class coefficient of 0.9) before and after infiltration using fluorescence microscopy. RESULTS: Reduction of enamel opaqueness was significantly higher in the experimental group (40.0% ± 18.5%) than in the control group (18.6% ± 14.9%) (P = 0.0105, one-tailed t-test; Hedge's g of 1.28, 95% confidence interval of 0.43/2.13, and power of 86%). CONCLUSIONS: It can be concluded that the application time of 30 min provides a greater reduction in opaqueness of proximal enamel lesion compared to the application time recommended by the manufacturer. The high effect size could stimulate patients to comply with the treatment time.

Natural enamel caries, dentine reactions, dentinal fluid and biofilm.

It is believed that penetration of dentinal fluid into natural enamel caries (NEC) is negligible because of the barrier created by underlying sclerotic dentine, but there are conflicting evidences on whether dentine subjacent to NEC is sclerotic or demineralized. This study aimed at investigating the relationship between NEC, subjacent dentine reactions, modification of dentinal fluid, and composition of cariogenic biofilm formed on the NEC surface. Proximal NEC (PNEC) lesions of human permanent posterior teeth were included in five experiments. Histologically, microradiographic analysis with contrast solution (MRC) in dentine revealed a decreased proportion of sclerotic dentine and an increased proportion of deep dentine demineralization compared to the classical stereomicroscopic histological analysis based on dentin color and translucency. Real-time MRC and 3D optical profilometry, and 3D microtomographic analysis evidenced a facilitated transport of modified dentinal fluid towards PNEC lesions. Cariogenic biofilm formed in vitro on the PNEC surface presented lower amounts of insoluble and soluble matrix polysaccharides when 2% chlorexidine was inserted in the pulp chamber. In conclusion, this study evidenced that dentine subjacent to PNEC is mostly demineralized, providing facilitated pathway for dentinal fluid to penetrate into PNEC and alter the composition of the biofilm formed on the PNEC surface.