Adhesive luting to hybrid ceramic and resin composite cad/cam blocks: Er:Yag laser versus chemical etching and micro-abrasion pretreatment

Purpose: To evaluate the effect of Er:YAG laser on the roughness, surface topography, and bond strength to resin luting cement based on chemical and micro-abrasion pretreatments of different computer-aided design/computer-aided manufacturing materials. Methods: A polymer-infiltrated-ceramic-network (PICN) material (Vita Enamic, VE), three indirect resin composite (Cerasmart, CS; Shofu HC, SH; Lava Ultimate, LU), and one lithium disilicate ceramic (IPS e.max CAD, EM) blocks were subjected to one of the following pretreatments: no treatment (NC ), Er:YAG etching with one of two powers (either 3 or 6 W), hydrofluoric acid (HF) etching, self-etching ceramic primer (ME), or micro-abrasion (MA). The shear bond strength (SBS) of resin luting cement to pretreated materials was tested. Surface roughness was measured via atomic force microscopy, and surface topography was analyzed via scanning electron microscopy. Two-way analysis of variance, Tukey post-hoc test, and Pearson correlation were applied. Results: Etching EM and VE with HF or the ME resulted in the highest SBS values in their groups (P < 0.05). LU, SH, VE, and CS indicated similar SBS values when treated with 3 W, 6 W, and MA. The highest surface roughness (Sa ) values were obtained for the LU, CS, and VE groups when treated with 6 W, whereas the lowest Sa values were obtained for CS when treated with the ME and EM when treated with the ME or 3 W. Only SH and CS indicated a significant correlation between surface roughness and bond strength. Conclusions: Er:YAG laser etching is comparable to micro-abrasion when treating resin composite blocks and may induce fewer surface cracks. HF etching remains the gold standard for the treatment of glass-based ceramics and PICNs. /© 2020 Japan Prosthodontic Society. All rights reserved

2D and 3D Wear Analysis of 3D Printed and Prefabricated Artificial Teeth

ABSTRACT: Purpose: This study aimed to assess the 3-body wear of prefabricated and 3D-printed artificial denture teeth. Materials and methods: Four groups of artificial teeth were used; 3D-printed polymethylmethacrylate (PMMA) teeth (PR) and 3 prefabricated commercially available denture teeth: PMMA (Gnathostar, GN), PMMA (SR Orthotyp PE, SR), and Nanohybrid composite (SR Phonares NHC, PH). The 3-body wear test was performed using a steatite ceramic antagonist in a chewing simulator with 750,000 cycles, temperature 23 ± 2 ˚C, and force of 50 N. The abrasive medium was composed of ground millet seeds and white rice mixed with distilled water. The teeth were 3D-scanned before and after the wear test. The 3D images were assessed for teeth wear by measuring the volumetric (3D wear) and the vertical (2D wear) substance loss. The one-way analysis of variance followed by Tukey post hoc test was used to statistically obtain the data analysis. Results: Maximum 3D wear was observed in the PR (51.05 ± 4.53 mm³), followed by GN (20.22 ± 6.29 mm³) and SR (12.12 ± 6.29 mm³) artificial teeth. Minimum wear occurred in the PH teeth (6.24 ± 0.87 mm³). The analytical differences amongst the groups were statistically significant (P < .05) except between PH and SR teeth. For 2D wear measurement, the maximum was seen in the GN teeth (6.29 ± 1.64 mm), followed by PR (5.04 ± 0.83 mm) and then SR (4.53 ± 0.87 mm). The PH teeth (3.09 ± 0.68 mm) again showed minimum wear. Statistically, amongst the groups, the major observable differences (P < .05) were between PH and GN, PH and PR, and SR and GN. Conclusions: Composite resin teeth had a greater wear resistance than acrylic resin teeth and 3D-printed resin teeth, both of which were comparable. Due to the advancement of digital workflows, manufacturers should devote effort to enhancing 3D-printed teeth

Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: Systematic review and network meta-analysis of randomised trials

Objective To determine the relative effectiveness of dietary macronutrient patterns and popular named diet programmes for weight loss and cardiovascular risk factor improvement among adults who are overweight or obese. Design Systematic review and network meta-analysis of randomised trials. Data sources Medline, Embase, CINAHL, AMED, and CENTRAL from database inception until September 2018, reference lists of eligible trials, and related reviews. Study selection Randomised trials that enrolled adults (�18 years) who were overweight (body mass index 25-29) or obese (�30) to a popular named diet or an alternative diet. Outcomes and measures Change in body weight, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, systolic blood pressure, diastolic blood pressure, and C reactive protein at the six and 12 month follow-up. Review methods Two reviewers independently extracted data on study participants, interventions, and outcomes and assessed risk of bias, and the certainty of evidence using the GRADE (grading of recommendations, assessment, development, and evaluation) approach. A bayesian framework informed a series of random effects network meta-analyses to estimate the relative effectiveness of the diets. Results 121 eligible trials with 21 942 patients were included and reported on 14 named diets and three control diets. Compared with usual diet, low carbohydrate and low fat diets had a similar effect at six months on weight loss (4.63 v 4.37 kg, both moderate certainty) and reduction in systolic blood pressure (5.14 mm Hg, moderate certainty v 5.05 mm Hg, low certainty) and diastolic blood pressure (3.21 v 2.85 mm Hg, both low certainty). Moderate macronutrient diets resulted in slightly less weight loss and blood pressure reductions. Low carbohydrate diets had less effect than low fat diets and moderate macronutrient diets on reduction in LDL cholesterol (1.01 mg/dL, low certainty v 7.08 mg/dL, moderate certainty v 5.22 mg/dL, moderate certainty, respectively) but an increase in HDL cholesterol (2.31 mg/dL, low certainty), whereas low fat (-1.88 mg/dL, moderate certainty) and moderate macronutrient (-0.89 mg/dL, moderate certainty) did not. Among popular named diets, those with the largest effect on weight reduction and blood pressure in comparison with usual diet were Atkins (weight 5.5 kg, systolic blood pressure 5.1 mm Hg, diastolic blood pressure 3.3 mm Hg), DASH (3.6 kg, 4.7 mm Hg, 2.9 mm Hg, respectively), and Zone (4.1 kg, 3.5 mm Hg, 2.3 mm Hg, respectively) at six months (all moderate certainty). No diets significantly improved levels of HDL cholesterol or C reactive protein at six months. Overall, weight loss diminished at 12 months among all macronutrient patterns and popular named diets, while the benefits for cardiovascular risk factors of all interventions, except the Mediterranean diet, essentially disappeared. Conclusions Moderate certainty evidence shows that most macronutrient diets, over six months, result in modest weight loss and substantial improvements in cardiovascular risk factors, particularly blood pressure. At 12 months the effects on weight reduction and improvements in cardiovascular risk factors largely disappear. Systematic review registration PROSPERO CRD42015027929. © Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ