Fit accuracy of removable partial denture metal frameworks produced by CAD-CAM – a clinical study

Objectives: To study the implementation of environmental sustainability practices at Portuguese dental clinics, the importance given by clinical directors to these practices, and the barriers felt in their applicability. Methods: This cross-sectional study’s target population was clinical directors (Dentists or Stomatologists) working in Portugal. Data was collected through an online questionnaire shared in several groups of clinicians on social networks, published in digital journals, and sent by email through medical associations. It was available between February and April 2021. The questionnaire collected information about the implementation of environmental sustainability practices in dental clinics within six categories of management: devices and equipment, dental amalgam, imaging, paper, energy, and water. There were also questions about the importance of these practices and the barriers felt. Descriptive statistics of all variables were performed. Results: The sample included 245 clinical directors, of which 65.5% were female and 43.7% were between 40 and 49 years old. There was a high degree of implementation of environmental sustainability practices related to imaging (82.6%), dental amalgam (80.7%), water (67.5%), energy (67.4%), paper (63.4%), and devices and equipment (62.9%). Almost all respondents (96%) considered that environmental sustainability practices are important or very important, and the more frequently referred barriers to implementation were costs (44.6%) and lack of training/information (16.3%). Conclusions: Clinical directors showed good environmental awareness and satisfactory implementation of environmental sustainability practices in dental clinics. Costs were the most reported barrier to the implementation of further practices.

Section: Discussionmentioning

confidence: 99%

Environmental sustainability practices in portuguese dental clinics

Neves¹,

Santos²,

Mendes³

2022

“…Developments in computer technology and software applications are a relevant part of the groundswell of technological change that has led additive manufacturing technique -3D printing -to where it is today. [5][6][7][8][9] 3D printers based on vat photopolymerization, namely stereolithography (SLA) and digital light projection (DLP), were the first commercially available and are still among the most used. 10,11 The emergence of these new technologies led to the development of new suitable materials.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and surface properties of a 3D-printed dental resin reinforced with graphene

Salgado¹,

Fialho²,

Marques³

et al. 2023

Objectives: Commercial photocurable polymers used in dental additive manufacturing still have mechanical limitations. The incorporation of graphene may provide interesting advantages in this field. This study aimed to evaluate in vitro the effect of adding graphene nanoparticles to a 3D-printed polymethylmethacrylate dental resin in terms of surface roughness, flexural properties, and hardness. Methods: A 3D-printed dental resin (Dental Sand, Harz Lab) was loaded with four different graphene nanoplatelet (Graphenest) concentrations: 0.01wt%, 0.1wt%, 0.25wt%, and 0.5wt%. The neat resin was used as the control group. The surface roughness was measured with a contact profilometer using bar-shaped specimens (50x10x4mm). The flexural strength of specimens (80x10x4mm) from each group was calculated using the 3-point bending test in a Universal Test Machine. Hardness shore D was measured using a manual durometer on round-shaped specimens (12x6mm). Data were evaluated using the Kruskall-Wallis test followed by post-hoc Bonferroni corrected pairwise inter-group comparisons. Statistical significance was set at p<0.05. Results: Graphene improved 3D-printed PMMA resin hardness with statistical significance at a concentration of 0.01wt% (p=0.043). Surface roughness increased with graphene concentrations above 0.01wt%, with statistically significant differences at 0.25wt% (p=0.006) and 0.5wt% (p=0.005) concentrations. Flexural properties worsened with increased graphene concentrations, and these differences were significant in the concentrations of 0.25wt% (p=0.028) and 0.5wt% (p=0.006). Conclusions: The use of graphene as a mechanical reinforcement nanomaterial seems to be viable at low concentrations without prejudice to the surface roughness of a 3D-printed polymethylmethacrylate resin.

“…4 Thus, in an attempt to overcome these limitations, new materials and manufacturing techniques have been proposed. 4,16,17 Digital denture manufacturing techniques reduce the cost and time of clinical and laboratory procedures, 18 besides pro-viding reproducibility by storing digital information. 7,14 Three-dimensional (3D) printing is a simple and recently introduced additive digital denture manufacturing technique with low material waste.…”

Section: Introductionmentioning

confidence: 99%

Microhardness and flexural strength of two 3D-printed denture base resins

Neves¹,

Chasqueira²,

Rebelo³

et al. 2022

Objectives: To evaluate the microhardness and flexural strength of printed and conventionally produced denture base acrylic resins. Methods: A total of 32 parallelepiped specimens (64×10×3.3 mm) were manufactured using two light-cured resins suitable for 3D printing (V-Print Dentbase and Denture 3D+) and two heat-cured resins for conventional production (Probase Hot and Villacryl Rapid) (n=8). After 24-h storage in water, Knoop microhardness (98.12 mN load for 30 s) and three-point flexural strength (1 kN load cell, at a crosshead speed of 5 mm/min and 50 mm between rods) were determined. Microhardness data were analyzed with one-way ANOVA followed by Tukey post-hoc tests. Flexural strength data were submitted to the Kruskal-Wallis test. A significance level of 5% was considered (α=0.05). Results: The resins showed statistically significant (p<0.001) differences regarding microhardness (V-Print Dentbase < Denture 3D+ < Probase Hot < Villacryl Rapid). No statistically significant (p=0.527) differences were found in flexural strength between the four resins. Conclusions: The printed resins had lower microhardness values than conventional resins, but all resins showed similar flexural strength.