Objective: The aim of this study was to compare five toothpastes in terms of alteration of surface roughness and colour of red-wine-stained human enamel over time after brushing simulation. Methods: Stained specimens were randomly divided into five groups (n = 8): Oral-B Gum and Enamel (C), ZACT Stain Fighter (ZW), Colgate Optic White Volcanic Mineral (CW), Oral-B 3D White Luxe Fresh Breath (3DW), and Thepthai (TW). The colour and surface roughness of the specimens were measured after brushing simulation for four durations; two weeks, one month, six months, and twelve months. Abrasive particles in toothpaste were inspected under a scanning electron microscope. Results: Surface roughness was increased in the specimens that underwent brushing simulation in all groups (p < 0.05). ZW (6.33 ± 0.98 μm) exerted the most changes in surface roughness for all durations. Other groups showed similar surface roughness at each time point. ΔE₀₀ and ΔL were increased in all groups until twelve months; however, there were no significant differences between C (ΔE₀₀ = 30.17 ± 4.16, ΔL = 38.19 ± 4.34), CW (ΔE₀₀ = 24.25 ± 10.52, ΔL = 31.12 ± 11.00), and TW (ΔE₀₀ = 29.00 ± 3.96, ΔL = 36.68 ± 4.53) at any time period. Moreover, ZW (ΔE₀₀ = 45.6 ± 8.01, ΔL = 53.03 ± 6.71) and 3DW (ΔE₀₀ = 43.6 ± 7.33, ΔL = 51.03 ± 6.47) exhibited a substantial change and were statistically differed from the other groups after four-weeks. Various characteristics of abrasive particles were inspected under SEM. Conclusion: All five toothpastes increased the surface roughness altered the colour of red wine-stained human enamel over time.

This study aimed to investigate the resin compounds from CAD-CAM 3D-printed denture resins, focusing on the identification and classification of free monomers and other components. The primary objective was to determine the chemical profile of these 3D-prinding resin materials. Four 3D-printed denture resins, two base materials (1: DentaBASE, Asiga Ltd., Alexandria, NSW, Australia; 2: DENTURETEC, SAREMCO Dental AG), and two tooth-colored materials (1: DentaTOOTH, Asiga Ltd.; 2: CROWNTEC (SAREMCO Dental AG), were analyzed using high-performance liquid chromatography and mass spectrometry (HPLC-MS). Data analysis was processed including peak alignment and normalization to an ethanol blank, resulting in detailed identification of compounds in the resin. Out of 5,208 detected compounds in the resin, 63 were retained after applying filtering criteria for further analysis, categorized into methyl methacrylate (MMA) and derivatives (31), photo initiators (8), UV stabilizers (1), and other additives (23). Sample 2B exhibited the highest number of resin compounds (62), including the most MMA derivatives and additives. MMA accounted for over 69% in abundance across samples, with unique additives such as ethyl-4-dimethylaminobenzoate and bis(acryloyloxymethyl) tricyclo[5.2.1.02,6] decane (TCD-DI-HEA) identified. Variations in the resin composition distribution and abundance highlighted differences in resin formulations. Within the limits of this in vitro, exploratory study, unpolymerized 3D-printed denture resins were analyzed, and various resin compounds in 3D-printed denture resins, including MMA, photo initiators, UV stabilizers, and additives, were identified along with significant variability between samples. While 3D-printing enhances efficiency and customization, further investigation is needed to better understand and assess the long-term intraoral effects and their effectiveness in complete dentures. This study provides insights into the chemical composition of 3D-printed denture resins, highlighting variability in resin compound profiles. Understanding these materials is essential for ensuring biocompatibility and performance. The findings support the need for further research and standardized testing to guide clinicians in the safe and effective use of 3D-printed dentures.

Objective The purpose of this study was to evaluate the microhardness and mineral composition alterations in enamel and dentine after radiotherapy. Materials and Methods Forty human maxillary premolar teeth (20 pairs) were assigned to nonirradiated and irradiated groups, the latter irradiated by fractional radiation to achieve a total dose of 70 Gy. Microhardness measurement was performed on a Knoop microhardness tester. Chemical components were analyzed using energy dispersive spectroscopy and Fourier transform Raman spectroscopy. The morphology was observed using a scanning electron microscope. The microhardness data were analyzed using a paired t-tested and one-way repeated analysis of variance (ANOVA), and the mineral composition data using related-samples Wilcoxon signed rank test and related-samples Friedman's two-way ANOVA by ranks. Results The irradiated teeth had a significantly lower microhardness in both enamel and dentine compared with the nonirradiated teeth. The irradiated dentine at 50 μm from the external tooth surface at the cemento-enamel junction showed the lowest microhardness compared with other locations. There was no statistically significant difference in calcium:phosphate ratio and chemical components. There was a reduction in protein:mineral ratio in dentine and at the cemento-enamel junction after irradiation. The irradiated teeth exhibited crack lines at the dentine-enamel junction and in dentine. Conclusion Fractional radiation reduced microhardness in both enamel and dentine. The cervical dentine exhibited the highest microhardness reduction compared with other enamel and dentine locations.

Objective: This study aimed to develop enamel substitute material using a mechanochemical technique. Materials and Methods: Hydroxyapatite was synthesized with and without tricalcium phosphate under uniaxial pressing of 10 and 17 MPa (HA10, HA17, BCP10, and BCP17), followed by sintering at 1250 °C for 2 h. Human enamel and dentin blocks were used as control groups. The mechanical properties were determined by compressive strength test and Vickers microhardness. The data were analyzed with one-way ANOVA and LSD post-hoc test (α = 0.05). The phase formation and morphology of the specimens were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results: HA17 and HA10 had compressive strength values comparable to enamel and dentin, respectively (p > 0.05). The microhardness of all synthesized groups was significantly higher than that of tooth structures (p < 0.05). From the XRD graphs, only the hydroxyapatite peak was observed in the control and HA groups. SEM images showed homogeneous hydroxyapatite grains in all groups, while the BCP groups contained higher porosities. Conclusions: Both HA10 and HA17 are suitable for use as the inorganic part of dentin and enamel substitutes.

Objectives This study evaluated surface roughness, biaxial flexural strength, and phase transformation of 5Y-PSZ after grinding and polishing with different protocols. Material and Methods Two commercial 5Y-PSZ, Lava Esthetic (L) and Cercon xt (C), were used and divided into 3 groups: LC and CC represented unpolished control groups; LE and CE were polished with protocol I (EVE DIASYNT® PLUS HP following with EVE DIACERA RA); and LJ and CJ were polished with protocol II (Superfine diamond bur following with Jota ZIR Gloss polishing kit). Surface roughness was evaluated after polishing step-by-step with a contact-type profilometer. After high-gross polishing, the specimens were subjected to biaxial flexural strength test, crystallographic microstructure analysis using an X-ray diffractometer (XRD), and surface micro-topography using scanning electron microscopy (SEM). Statistical Analysis Surface roughness differences after each step and biaxial flexural strength between groups were evaluated with one-way ANOVA, followed by Bonferroni post-hoc analysis. Changes in surface roughness across four different time points within groups were assessed using one-way repeated measures ANOVA, followed by Bonferroni post-hoc analysis. Results After high-gross polishing, both polishing protocols showed significantly lower surface roughness than the grinding group (p < 0.05). The LE and CE groups exhibited the highest surface roughness values, which were significant differences from the LJ and CJ groups (p < 0.05). The LE group showed significantly lower biaxial flexural strength compared to the LC group (p < 0.05). However, there was no statistically significant difference in the CE and CJ groups compared to the control group (p > 0.05). Furthermore, all polishing protocols did not change the phase transformation of zirconia. Conclusion Polishing protocol II provided a smoother surface than the protocol I after high-gross polishing, while the biaxial flexural strength of materials remained unaffected.

To evaluate the clinical and biomarker outcomes of photodynamic therapy (PDT) as an adjunct to non-surgical mechanical debridement (MD) in the management of peri‑implantitis, and to compare its efficacy to MD alone or other non-surgical treatment modalities. Electronic searches in PubMed, Web of Science, and CENTRAL were conducted. 4675 studies published until November 2023 were screened. Clinical studies reporting on non-surgical treatments involving PDT were selected. Meta-analyses assessed clinical parameters (bleeding on probing [BOP], probing depth [PD], plaque index [PI], crestal bone loss [CBL], clinical attachment level [CAL]) and biomarkers. A total of 25 studies were included. The meta-analysis of randomized controlled trials revealed that both MD alone and MD+PDT significantly improved clinical and biomarker outcomes compared to baseline. The addition of PDT provided greater improvements at 3 months for BOP (SMD:0.90; 95 % CI:1.53 to -0.28; p = 0.005), PD (SMD:1.15; 95 % CI:1.72 to -0.58; p < 0.0001), PI (SMD:0.74; 95 % CI:1.15 to -0.33; p = 0.0004) and CBL (SMD:0.38; 95 % CI:0.73 to -0.03; p = 0.04). The additional benefits of PDT were less pronounced on CAL, mucosal recession, and inflammatory biomarkers. No significant changes were observed over extended follow-up periods. Adjunct PDT significantly enhanced clinical outcomes, particularly for the short-term, with the most notable benefits observed in BOP, PD, PI, and CBL reductions. However, additional benefits in CAL, mucosal recession, and inflammatory biomarkers outcomes remain limited. Standardized protocols and long-term studies are warranted. PDT as an adjunct in non-surgical peri-implantitis management improves short-term clinical outcomes, particularly for BOP, PD, PI, and CBL. The benefits of adjunctive use with mechanical debridement offer a promising and minimally invasive approach. Further long-term research is needed to establish its role in routine clinical practice.