The integration of computer-aided design and computer-aided manufacture (CAD-CAM) technology has revolutionized restorative dentistry, offering both additive and subtractive manufacturing methods. Despite extensive research on 3-dimensionally (3D) printed materials, uncertainties remain regarding the impact of print orientation on their mechanical properties, especially for definitive resin materials, necessitating further investigation to ensure clinical efficacy. The purpose of this in vitro study was to investigate the influence of print orientation and artificial aging on the flexural strength (FS) and flexural modulus (FM) of 3D printed resin materials indicated for definitive and interim restorations. Specimens (2×2×25 mm) were additively manufactured in 3 orientations (0, 45, and 90 degrees) using five 3D printed resins: VarseoSmile Crownplus (VCP), Crowntec (CT), Nextdent C&B MFH (ND), Dima C&B temp (DT), and GC temp print (GC). A DLP 3D printer (ASIGA MAX UV) was used with postprocessing parameters as per the manufacturer recommendations. FS and FM were tested after storage in distilled water (DW) and artificial saliva (AS) for 24 hours, 1 month, and 3 months at 37 °C. Additional 2×2×16-mm specimens printed at 90 degrees were compared with the milled materials Lava Ultimate (LU) and Telio CAD (TC) after 24 hours of storage in AS at 37 °C (n=10). Measurements were conducted using a universal testing machine (Z020; Zwick/Roell) following the International Organization for Standardization (ISO) 4049 standard. Multiple way ANOVA, 1-way ANOVA, and Tukey HSD post hoc tests (α=.05) were used to analyze the data. Print orientation significantly influenced the FS and FM of 3D printed resin materials, with the 90-degree orientation exhibiting superior mechanical properties (P<.05). Definitive resins (CT and VCP) exhibited higher FS and FM compared with interim resins (ND, DT, GC) at all time points (P<.001). LU had significantly higher FS and FM compared with other resins (P<.001), while TC had similar FS to definitive 3D printed resins. Aging time and media influenced FS and FM, with varying effects observed across different materials and time points. Strong positive correlations were found between filler weight and both FS (r=.83, P=.019) and FM. All materials met the minimum FS requirement of 80 MPa (ISO 4049) when printed at 90 degrees. The 90-degree orientation produced specimens with higher FS than 0- and 45-degree orientations. CT recommended for definitive restorations displayed higher FS compared with VCP and those intended for interim use after 3 months of aging. LU exhibited higher FS and FM than 3D printed resins, while TC had similar FS and FM to the latter. Aging effects on 3D printed resins were minimal and were material specific.

Objective: To evaluate and compare the surface roughness and gloss of a DMA-free composite and Bis-GMA-free composite with a DMA-based composite before and after toothbrushing simulation. Materials and Methods: Fifteen dimensionally standardised composite specimens of three nano-hybrid resin composites (Tetric EvoCeram, Admira Fusion, and Venus Diamond) were used. Five specimens from each composite were polished and then subjected to a toothbrushing simulator. Surface roughness (Ra) and gloss were measured before toothbrushing and after 5000, 10,000, 15,000, and 20,000 toothbrushing cycles. The data was analysed using 5 × 3 ANOVA to assess surface roughness and gloss values and pairwise comparisons in the form of Tukey post hoc tests were performed to interpret main effects. Results: For all tested materials, surface roughness increased, and gloss decreased after toothbrushing abrasion. Surface roughness (Ra) values ranged from 0.14 to 0.22 μm at baseline and increased to between 0.41 and 0.49 μm after 20,000 toothbrushing cycles. Gloss values ranged between 31.9 and 50.6 GU at baseline and between 5.1 and 19.5 GU after 20,000 toothbrushing cycles. The lowest initial Ra value was detected in Venus Diamond and the highest initial gloss value was detected in Tetric EvoCeram. Conclusions: Simulated toothbrushing abrasion led to an increase in surface roughness and a decrease in gloss for all tested materials. Venus Diamond had the smoothest surface and Tetric EvoCeram had the glossiest surface after polishing and following 20,000 cycles of toothbrushing abrasion. Admira Fusion demonstrated the roughest surface and had the lowest gloss values before and after toothbrushing abrasion.

Background: Little is known about the oral disease burden in refugee children and associated risk factors. This cross-sectional study aimed to explore the oral hygiene status and prevalence of caries, and to investigate their association with malocclusion characteristics in a child refugee population. Methods: 606 Syrian refugee children and adolescents aged 7–19 years, registered as refugees in Jordan and residing in Zaatari camp, were recruited to the study. Oral hygiene and caries status were recorded using DMFT (mean of decayed, missing, and filled permanent teeth) and OHI-S (Simplified Oral Hygiene Index) according to WHO criteria. Oral health results were then cross tabulated with previously reported malocclusion traits for the same study sample (crowding, spacing, contact point deflection and IOTN) to detect any associations. Statistical analysis was conducted using chi-square test, independent sample t-test, one-way ANOVA, Welch test and Post Hoc testing (Gabriel and Games-Howell). Results: Overall DMFT and OHI-S were 4.32 and 1.33 respectively with no difference between males and females. Around 40% of the sample showed ≥ 5 DMFT score. 96.1% of the sample either do not brush or brush occasionally: females showed better oral hygiene practices (P = 0.002). No significant differences in DMFT scores were noted for gender or age, other than the 7–9.9 year old group having significantly higher mean DMFT scores than all other age groups (P < 0.01);the mean of OHI-S was not significantly different between different age groups (P = 0.927). Subjects with malocclusion, specifically crowding, contact point deflection and IOTN grades 3, 4 and 5 had higher scores in both arches for OHI-S and DMFT than subjects without malocclusion traits, although this was not statistically significant for DMFT scores. Overall, patients with generalized spacing had a significantly lower OHI-S score than those without spacing (P = 0.021). Significant correlations were found between parameters of intra-arch and inter-arch relationships and oral health indices (DMFT and OHI-S). Conclusion: Malocclusion may increase the risk of caries and periodontal disease; the magnitude of this risk is amplified in populations with poor oral health and limited access to oral healthcare services, highlighting the need for preventive and curative oral health programs.

Three-dimensional (3D) printing is increasingly used to fabricate dental restorations due to its enhanced precision, consistency and time and cost-saving advantages. The properties of 3D-printed resin materials can be influenced by the chosen printing orientation which can impact the mechanical characteristics of the final products. The objective of this study was to evaluate the influence of printing orientation and artificial ageing on the Martens hardness (HM) and indentation modulus (E_IT) of 3D-printed definitive and temporary dental restorative resins. Disk specimens (20 mm diameter × 2 mm height) were additively manufactured in three printing orientations (0°, 45°, 90°) using five 3D-printable resins: VarseoSmile Crownplus (VCP), Crowntec (CT), Nextdent C&B MFH (ND), Dima C&B temp (DT), and GC temp print (GC). The specimens were printed using a DLP 3D-printer (ASIGA MAX UV), while LavaTM Ultimate (LU) and Telio CAD (TC) served as milled control materials. Martens hardness (HM) and indentation modulus (E_IT) were tested both before and after storage in distilled water and artificial saliva for 1, 30, and 90 days at 37 °C. 90° printed specimens exhibited higher HM than the other orientations at certain time points, but no significant differences were observed in HM and E_IT between orientations for all 3D-printed materials after 90 days of ageing in both aging media. LU milled control material exhibited the highest HM and E_IT among the tested materials, while TC, the other milled control, showed similar values to the 3D printed resins. CT and VCP (definitive resins) and ND displayed higher Martens parameters compared to DT and GC (temporary resins). The hardness of the 3D-printed materials was significantly impacted by artificial ageing compared to the controls, with ND having the least hardness reduction percentage amongst all 3D-printed materials. The hardness reduction percentage in distilled water and artificial saliva was similar for all materials except for TC, where higher reduction was noted in artificial saliva. The used 3D printed resins cannot yet be considered viable alternatives to milled materials intended for definitive restorations but are preferable for use as temporary restorations.