A 24-month clinical evaluation of composite resins with different viscosity and chemical compositions: a randomized clinical trial.

OBJECTIVES: To evaluate the clinical performance of two methacrylate-based flowable composites and an ormocer-based flowable composite in noncarious cervical lesions (NCCLs) in adult participants. METHOD AND MATERIALS: In total, 183 restorations were performed on NCCLs. All cavities were restored using a universal adhesive system (Futurabond U, Voco) with selective enamel etching and with one of the three evaluated flowable composites (n = 61): low-viscosity methacrylate-based composite (GrandioSO Flow, LV), high-viscosity methacrylate-based composite (GrandioSO Heavy Flow, HV), and an ormocer-based flowable composite (Admira Fusion Flow, ORM). All restorations were evaluated using FDI and USPHS criteria after 24 months. Kruskall-Wallis analysis of variance rank (α = .05) was used for statistical analysis. RESULTS: After 24 months of clinical evaluation, 16 restorations were lost (LV = 3, HV = 10, ORM = 3) and the retention rates (95% confidence interval) were 95.0% for LV, 82.2% for HV, and 95.0% for ORM, with statistical differences observed between HV and LV as well as HV and ORM (P < .05). When secondary parameters were evaluated, no significant differences between groups were observed (P > .05). Thirty-three restorations (LV = 8, HV = 13, ORM = 12) showed minor marginal staining, 71 restorations (LV = 26, HV = 20, ORM = 25) presented small marginal adaptation defects, and one restoration for HV presented recurrence of caries. CONCLUSION: The universal adhesive associated with the ormocer-based and methacrylate-based flowable composite showed promising clinical performance after 24 months. However, the heavy-flow restorations showed significantly more failures. (Quintessence Int 2023;54:186-199; doi: 10.3290/j.qi.b3631841).

Assessment of the effect of experimental bleaching agent with nano-bioactive material on postoperative sensitivity: A randomized, triple blind clinical trial.

OBJECTIVES: This clinical study aimed to evaluate the effect of incorporating bioactive nanoparticles (n-Bm) inside an in-office bleaching gel on the risk and intensity of tooth sensitivity (TS) and on bleaching effectiveness. MATERIALS AND METHODS: Sixty-six participants were selected and randomly assigned into two groups: control-only in-office gel and experimental-in-office gel with n-Bm. Teeth were bleached in two sessions (3 × 15-min). TS was recorded using a VAS and NRS. The color change was evaluated by subjective (VITA Classical and VITA Bleachedguide) and objective (Easyshade spectrophotometer) methods at baseline and 30 days after the end of treatment. The TS was evaluated by McNemar, Wilcoxon Signed Rank, and paired t test. The color changes between groups were compared using paired t test (α = 0.05). RESULTS: No significant differences between the groups were observed in the risk (control = 27% [95%IC 18-39]; experimental = 21% [95%IC 13-32]) and intensity of TS, as well as in the color change (p >0.05) for any color measurement. CONCLUSION: The inclusion of n-Bm into the bleaching agents did not affect the whitening effectiveness, as well as the risk and intensity of TS between groups. However, the results of the absolute risk of TS were low for both in-office gels used. CLINICAL SIGNIFICANCE: Despite no significant differences between groups, both experimental bleaching agents present suitable results with low values for TS.

Influence of flavonoids on long-term bonding stability on caries-affected dentin.

OBJECTIVES: To evaluate the effect of experimental dentin pre-treatment solutions formulated with different flavonoids on microtensile bond strength (µTBS), nanohardness (NH) and ultra-morphological characteristics of artificial caries-affected dentin (CAD) bonded using a universal bonding system. METHODS: A microbiological method was used to create an artificial CAD in 91 human molars. Five experimental pre-treatment solutions were created using the following flavonoids: quercetin (QUE); hesperidin (HES); rutin (RUT); naringin (NAR), or proanthocyanidin (PRO). A placebo solution (PLA) with no flavonoids added was also evaluated. The flavonoids or placebo solutions were applied to the CAD prior to the application and photoactivation of a universal adhesive (Scotchbond Universal, 3M Oral Care). A control group (CON), in which only the bonding agent was applied without any flavonoid solution, was also evaluated. A 3-mm-thick block of resin composite (Opallis, FGM) was built up on the flat bonded CAD surfaces and was light-cured following the manufacturer's instructions. Specimens were sectioned to obtain resin-dentin slices and sticks (cross-sectional area of 0.8 mm2). The µTBS, NH, and confocal ultramorphology analysis of resin-dentin interface was evaluated at 24 h and after thermo-cycling aging (25,000 cycles). The results were analyzed using 2-way ANOVA followed by Bonferroni's post hoc test (pre-set α = 0.05). RESULTS: The specimens from groups QUE, NAR, and RUT presented greater µTBS values than those from CON group (p<0.05). Specimens from some of these experimental groups presented greater nanomechanical properties (p<0.05), and no morphological degradation at the resin-dentin interface after aging. SIGNIFICANCE: The use of exogenous cross-linkers as dentin pre-treatment before bonding procedures may represent a suitable strategy to improve the longevity of universal adhesive systems applied to caries-affected dentin.

Monumental architecture at Aguada Fénix and the rise of Maya civilization.

Archaeologists have traditionally thought that the development of Maya civilization was gradual, assuming that small villages began to emerge during the Middle Preclassic period (1000-350 BC; dates are calibrated throughout) along with the use of ceramics and the adoption of sedentism1. Recent finds of early ceremonial complexes are beginning to challenge this model. Here we describe an airborne lidar survey and excavations of the previously unknown site of Aguada Fénix (Tabasco, Mexico) with an artificial plateau, which measures 1,400 m in length and 10 to 15 m in height and has 9 causeways radiating out from it. We dated this construction to between 1000 and 800 BC using a Bayesian analysis of radiocarbon dates. To our knowledge, this is the oldest monumental construction ever found in the Maya area and the largest in the entire pre-Hispanic history of the region. Although the site exhibits some similarities to the earlier Olmec centre of San Lorenzo, the community of Aguada Fénix probably did not have marked social inequality comparable to that of San Lorenzo. Aguada Fénix and other ceremonial complexes of the same period suggest the importance of communal work in the initial development of Maya civilization.