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Effect of phototherapy on dentin bond strength and microleakage when bonded to resin with different conditioning regimes
摘要： Aim To assess the efficacy of phototherapy on bond strength and microleakage of bulk fill composites in comparison to conventional dentin surface treatments. Materials and Methods Ninety human third molars were divided into 3 groups (n=30 each) according to surface conditioning treatment. Group 1 (Etch and Bond) EB, group 2 was treated with Er,Cr: YSGG (ECL) and group 3 was treated with a diode laser (DL). Based on the type of bulk fill resin composite, samples were divided into six sub-groups. In sub-group 1, 2 and 3 (n=15) build-up was done using ZirconCore (ZC) and these subgroups were named as EB-ZC, ECL-ZC and DL-ZC. In subgroup 4,5,6 (n=15) MulticCore Flow (MC) was used for core build-up and these subgroups were named as EB-MC, ECL-MC, DL-MC. For shear bond strength (SBS) all the samples were exposed to loads using a universal testing machine. Five samples each from all subgroups were immersed in methylene blue dye for 24hours prior to microleakage testing. Data were assessed using analysis of variance and Tukey multiple comparisons test. Results: Among all the groups the lowest bond strength was achieved in DL-ZC [10.45(0.459)]. Similarly, the highest bond strength was attained in EB-MC[17.84(0.925)]. The highest microleakage scores amongst different group was exhibited in DL-ZC [82.45(39.459)] whereas, the lowest microleakage scores were displayed in EB-MC [31.21(15.92)]. Conclusion: Phototherapy in the form of Er,Cr:YSGG laser showed comparable adhesive bond outcomes to conventional etch and bond dentin conditioning techniques. Moreover, Multicore bulk fill material showed better bond strength and microleakage scores than zirconium particle infiltrated bulk fill composite in the presence of dentin phototherapy.
关键词： dentine,bond strength,Cr: YSGG,microleakage,Er,bulk fill composite
更新于2025-09-23 15:23:52
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Novel Confocal-Laser-Scanning-Microscopy and conventional measures investigating eroded dentine following dentifrice dab-on and brushing abrasion
摘要： Objectives: To validate novel non-contacting Confocal-Laser-Scanning-Microscopy (CLSM) methodology with conventional Contacting Pro?lometry (CP) measures investigating brushing or dab-on of stannous-?uoride dentifrice on early aggressive dentine erosion. Methods: 75 polished human dentine samples were prepared and eroded in agitated 6% citric acid then randomly allocated into 5 intervention groups; arti?cial saliva control (1); controlled use of a pressure sensitive counter-rotating oscillatory powered toothbrush with sodium-?uoride NaF (2) or stannous-?uoride SnF2 (3), and dab-on application of NaF (4) or SnF2 (5). Samples underwent three cycles of intervention and 2-min agitated 6 % citric acid challenges. CLSM images were taken and 3D reconstructions produced of step height using a developed software algorithm. In addition, 20 % samples were randomised and pro?led using CP to measure step height and surface roughness. Vickers's diamond micro-hardness testing was carried out on all samples. Results: Comparing CLSM and CP; Pearson correlation was 0.77 and Intra-class correlation 0.81 (p ? 0.01). There were no signi?cant statistical differences in step height between groups using both CLSM and CP. From baseline, SnF2 brushing (3) increased micro-hardness more than control (1) (p ? 0.03), NaF (4) and SnF2 dab-on (5) (p (cid:2) 0.001), and increased surface roughness more than control (p ? 0.02), NaF brushing (2) and NaF dab-on (4) (p (cid:2) 0.017). Dab-on of SnF2 (5) produced rougher surfaces than control (1) (p ? 0.014) and reduced hardness compared with NaF brushing (p ? 0.04). Conclusions: Good agreement and correlation exists between CLSM and CP measures in dentine. There were no signi?cant differences in surface loss after interventions between groups. Compared with control, SnF2 application increased dentine surface roughness and SnF2 controlled powered brushing application increased dentine hardness, likely caused by exposure of uneroded dentine. Clinical signi?cance: Isosurfaces produced using CLSM can be used to represent dentine step height loss. They show good correlation and agreement with conventional CP measures, following early aggressive erosion-abrasion cycles of dentine. The CLSM and computer algorithm therefore provides an accurate, standalone and non-contacting three-dimensional measurement of early dentine wear. Stannous-?uoride brushing, and dab-on application offer no bene?ts following early aggressive erosion in dentine. To reduce dentine wear, limiting erosive challenges and avoiding brushing post-erosion is advised.
关键词： Prosthetic dentistry,Medical imaging,Dab-on,Mathematical biosciences,Dental materials,Biophysics,Dentistry,Erosion,Measurement,Software engineering,Applied computing in medical science,Abrasion,Dentifrice,Biocomputational method,Dentine-wear
更新于2025-09-16 10:30:52
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Efficacy of low‐level laser therapy associated with fluoride therapy for the desensitisation of Molar‐incisor hypomineralisation: randomised clinical trial
摘要： Background. Molar-incisor hypomineralisation (MIH) is a qualitative enamel defect. Aim. Investigate the low-level laser therapy (LLLT) associated with fluoride varnish for the desensitisation of teeth with MIH. Design. A randomised clinical trial was conducted with 66 children, randomly allocated to the treatments: laser (L); fluoride varnish (FV); and laser + fluoride varnish (L+FV). The participants in the L group underwent two sessions of LLLT (48-hour interval). The FV group received four applications of varnish at one-week intervals. The L+FV underwent two sessions of LLLT and four applications of varnish. Prior to each session and one month after the onset of treatment, tooth sensitivity and its magnitude were evaluated. Intra and inter-group comparisons were performed (α = 5%). Results. A significant reduction in the mean sensitivity score was found over time in all groups. After the final treatment, as significant difference was found between the L and L+FV group (p = 0.011), with a lower score in the L+FV group (0.09), whereas no difference was found between the FV and L+FV groups (p = 0.095). Conclusions. Fluoride varnish and the combination of treatments (L+FV) had greater desensitising action on teeth with MIH. Laser therapy demonstrated an immediate desensitising effect, whereas fluoride varnish had a late-onset effect.
关键词： Child,Tooth demineralisation,Fluoride, topical,Low-level laser light therapy,Dentine sensitivity
更新于2025-09-12 10:27:22
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Chemical analysis of in vivo–irradiated dentine of head and neck cancer patients by ATR-FTIR and Raman spectroscopy
摘要： Objectives To evaluate the effect of in vivo radiotherapy on the chemical properties of human dentine by Fourier-transform infrared spectroscopy (FTIR) and Raman analysis. Materials and methods Chemical composition was evaluated comparing control and irradiated group (n = 8). Irradiated teeth were obtained from radiotherapy patients subjected to fractionated X-ray radiation of 1.8 Gy daily totaling 72 Gy. The teeth were sectioned according to the type of dentine (crown or root dentine), obtaining 3-mm dentine cervical slices. The analyzed parameters by FTIR and Raman spectroscopies were mineral/matrix ratio (M:M), carbonate/mineral ratio (C:M), amide I/amide III ratio, and amide I/CH2 ratio. Raman also calculated the phosphate and carbonate crystallinity. Results FTIR revealed that M:M had a decrease in both factors (p = 0.008; p = 0.043, respectively) and root dentine showed a lower C:M in the irradiated group (p = 0.003). Raman revealed a higher phosphate crystallinity and a lower carbonate crystallinity in crown dentine of irradiated group (p = 0.021; p = 0.039). For amide I/amide III, the irradiated showed a lower ratio when compared to the control group (FTIR p = 0.002; Raman p = 0.017). For amide I/CH2, the root dentine showed a higher ratio than the crown dentine in both methods (p < 0.001). Conclusions Radiotherapy altered the chemical composition of human dentine. The exchange of phosphate-carbonate ions in the hydroxyapatite and higher concentration of organic components was found after radiotherapy. Clinical relevance The increased risk of radiation-related caries in patients undergoing head and neck radiotherapy is due not only to salivary, dietary, and microbiological changes but also to changes in tooth chemical composition.
关键词： Radiotherapy,Raman spectroscopy,Head and neck cancer,Fourier-transform infrared spectroscopy,Dentine
更新于2025-09-09 09:28:46