Influence of different printing orientations and post-polymerization time on the translucency of three-dimensional (3D) printed denture base resins.

PURPOSE: To evaluate the effect of different printing orientations and post-polymerization time with thermal cycling on the translucency of 3D-printed denture base resins. METHODS: Heat-polymerized (HP) acrylic resin specimens were fabricated and 3D-printed denture base materials (NextDent, ASIGA, FormLabs) were printed with different printing orientations (0, 45, 90 degrees) and subjected to different post-polymerization times (15-, 30-, 60-, and 90-min). All specimens were polished and immersed in distilled water for 1 day at 37°C. CIEDE2000 was used to measure the translucency parameters (TP00) before and after thermal cycling (5000 cycles) recording the color parameters (L*, a*, b*) against a black and white background using a spectrophotometer. k-factors ANOVA followed by post hoc Tukey's test (α = .05) was performed for statistical analysis. RESULTS: The k-factors ANOVA test showed a significant effect of resin material, post-polymerization time, and printing orientation on translucency (p < 0.001). In comparison to HP, all 3D-printed resins showed lower translucency with all post-polymerization times and printing orientation (p < 0.001) except FormLabs resin (p > 0.05). For all 3D-printed resins, the translucency increased, with increasing the post-polymerization time (p < 0.001) and 60- and 90-min showed the highest translucency. For printing orientation, 90 and 45 degrees significantly showed high translucency in comparison to 0 degrees (p < 0.001). FormLabs showed significantly higher translucency when compared with NextDent and ASIGA per respective printing orientation and post-polymerization time. The translucency significantly decreased after thermal cycling for all tested resins (p < 0.001). CONCLUSION: The findings of this study demonstrated that the translucency of 3D-printed resins is influenced by the printing orientation, post-polymerization time, and resin type. As a result, choosing a resin type, and printing orientation, with a longer post-polymerization time should be considered since it may improve the esthetic appearance of the 3D-printed resins.

Salivary interleukin-17A and interleukin-18 levels in patients with celiac disease and periodontitis.

Background: An increased level of interleukin-17A and interleukin-18 in the serum and intestinal mucosa of celiac disease patients reflecting the severity of villous atrophy and inflammation was documented. Thus, the objective of this study was to evaluate the concentrations of salivary-17A, interleukin-1 beta, and interleukin-18 in patients with celiac disease who are on a gluten-free diet, both with and without periodontitis, and to compare these levels with those in healthy individuals. Methods: The study involved 23 participants with serologically confirmed celiac disease (CD) and 23 control subjects. The CD patients had been following a gluten-free diet (GFD) for a minimum of 1 year and had no other autoimmune disorders. The research involved collecting demographic data, conducting periodontal examinations, gathering unstimulated whole saliva, and performing enzyme-linked immunosorbent assays to measure salivary interleukin-17A, interleukin-1 beta, and interleukin-18 levels. Spearman's correlation analysis was utilized to explore the relationships between CD markers in patients on a GFD and their periodontal clinical findings. Results: The periodontal findings indicated significantly lower values in celiac disease patients adhering to a gluten-free diet compared to control subjects (p = 0.001). No significant differences were found in salivary IL-17A, IL-18, and IL-1B levels between celiac disease patients and control subjects. Nevertheless, the levels of all interleukins were elevated in periodontitis patients in both the celiac and control groups. The IL-1 Beta level was significantly higher in periodontitis patients compared to non-periodontitis patients in the control group (p = 0.035). Significant negative correlations were observed between serum IgA levels and plaque index (r = -0.460, p = 0.010), as well as gingival index (r = -0.396, p = 0.030) in CD patients on a gluten-free diet. Conclusion: Celiac disease patients on gluten-free diet exhibited better periodontal health compared to control subjects. However, increased levels of salivary IL-17A, IL-18 and IL-1B levels were associated with periodontitis. Additionally, serum IgA level was significantly inversely associated with periodontitis clinical manifestations and with salivary inflammatory mediators in CD patients on GFD.

Flexural strength of 3D-printed nanocomposite provisional resins: Impact of SiO2 and ZrO2 nanoparticles and printing orientations in vitro.

PURPOSE: The aim of this study was to investigate and compare the influence of zirconium dioxide nanoparticles (ZrO2 NPs) and silicon dioxide nanoparticles (SiO2 NPs) addition and printing orientation on the flexural strength (FS) of provisional three-dimensional (3D) printing resins undergoing thermal cycling (TC). METHODS: Three dimensional-printed resin (NextDent C&B MFH) was used to fabricate 300 bar-shaped specimens (25 × 2 × 2 mm3 ). The ZrO2 NPs and SiO2 NPs specimens were divided into two groups, then subdivided into three groups, based on the nanoparticle concentration (i.e., 0 wt% (original group), 0.5 wt%, and 1 wt%). Each concentration was printed in three printing orientations (0°, 45°, and 90°). The printed specimens were exposed to 5000 cycles of TC, followed by a three-point bending test to assess the FS. Fracture surface analysis was conducted by using a scanning electron microscope (SEM). For data analysis, ANOVA and Tukey's post hoc were utilized (α = 0.05). RESULTS: Compared to the original material, the addition of ZrO2 NPs and SiO2 NPs had a significantly positive impact on the FS, (P > 0.001). After TC, the FS of the original group decreased significantly and had the lowest value. The highest FS value was observed in 1% ZrO2 NPs at 0°. Regardless of the nanoparticle concentration, the 0° orientation consistently showed a higher FS, compared to the 45° and 90° orientations. At all orientations (i.e., 0°, 45°, and 90°), the FS significantly increased with the addition of NPs, compared with that of the original material (P > 0.001). TC had a significantly negative effect on the FS of the unmodified groups. However, no significant differences existed in FS among the modified groups after TC. CONCLUSION: The addition of SiO2 NPs and ZrO2 NPs increased the FS of the 3D-printed provisional resin. Regardless of the nanoparticle concentration, the 0° orientation had the higher FS. TC had an effect on the original resin, whereas it had no significant effect on the nanoparticle-modified resins. In clinical practice, 3D-printed provisional nanocomposite resins printed at the 0° orientation could be recommended for long-term dental provisional restorations.

Comparative Evaluation of TiO2 Nanoparticle Addition and Postcuring Time on the Flexural Properties and Hardness of Additively Fabricated Denture Base Resins.

Three-dimensionally (3D)-printed fabricated denture bases have shown inferior strength to conventional and subtractively fabricated ones. Several factors could significantly improve the strength of 3D-printed denture base resin, including the addition of nanoparticles and post-curing factors. This study evaluated the effect of TiO2 nanoparticle (TNP) addition and the post-curing time (PCT) on the flexural properties and hardness of three-dimensionally (3D)-printed denture base resins. A total of 360 specimens were fabricated, with 180 specimens from each type of resin. For evaluating the flexural properties, bar-shaped specimens measuring 64 × 10 × 3.3 mm were used, while, for the hardness testing, disc-shaped specimens measuring 15 × 2 mm were employed. The two 3D-printed resins utilized in this study were Asiga (DentaBASE) and NextDent (Vertex Dental B.V). Each resin was modified by adding TNPs at 1% and 2% concentrations, forming two groups and an additional unmodified group. Each group was divided into three subgroups according to the PCT (15, 60, and 90 min). All the specimens were subjected to artificial aging (5000 cycles), followed by testing of the flexural strength and elastic modulus using a universal testing machine, and the hardness using the Vickers hardness test. A three-way ANOVA was used for the data analysis, and a post hoc Tukey's test was used for the pairwise comparisons (α = 0.05). Scanning electron microscopy (SEM) was used for the fracture surface analysis. The addition of the TNPs increased the flexural strength in comparison to the unmodified groups (p < 0.001), while there was no significant difference in the elastic modulus and hardness with the 1% TNP concentration. Among the TNP groups, the 2% TNP concentration significantly decreased the elastic modulus and hardness (p < 0.001). The SEM showed a homogenous distribution of the TNPs, and the more irregular fracture surface displayed ductile fractures. The PCT significantly increased the flexural strength, elastic modulus, and hardness (p < 0.001), and this increase was time-dependent. The three-way ANOVA results revealed a significant difference between the material types, TNP concentrations, and PCT interactions (p < 0.001). Both concentrations of the TNPs increased the flexural strength, while the 2% TNP concentration decreased the elastic modulus and hardness of the 3D-printed nanocomposites. The flexural strength and hardness increased as the PCT increased. The material type, TNP concentration, and PCT are important factors that affect the strength of 3D-printed nanocomposites and could improve their mechanical performance.

Repair Bond Strength of Conventionally and Digitally Fabricated Denture Base Resins to Auto-Polymerized Acrylic Resin: Surface Treatment Effects In Vitro.

Denture base fracture is one of the most annoying problems for both prosthodontists and patients. Denture repair is considered to be an appropriate solution rather than fabricating a new denture. Digital denture fabrication is widely spreading nowadays. However, the repair strength of CAD-CAM milled and 3D-printed resins is lacking. This study aimed to evaluate the effect of surface treatment on the shear bond strength (SBS) of conventionally and digitally fabricated denture base resins. One l heat-polymerized (Major base20), two milled (IvoCad, AvaDent), and three 3D-printed (ASIGA, NextDent, FormLabs) denture base resins were used to fabricate 10 × 10 × 3.3 acrylic specimens (N = 180, 30/resin, n = 10). Specimens were divided into three groups according to surface treatment; no treatment (control), monomer application (MMA), or sandblasting (SB) surface treatments were performed. Repair resin was bonded to the resin surface followed by thermocycling (5000 cycles). SBS was tested using a universal testing machine where a load was applied at the resin interface (0.5 mm/min). Data were collected and analyzed using ANOVA and a post hoc Tukey test (α = 0.05). SEM was used for failure type and topography of fractured surfaces analysis. The heat-polymerized and CAD-CAM milled groups showed close SBS values without significance (p > 0.05), while the 3D-printed resin groups showed a significant decrease in SBS (p < 0.0001). SBS increased significantly with monomer application (p < 0.0001) except for the ASIGA and NextDent groups, which showed no significant difference compared to the control groups (p > 0.05). All materials with SB surface treatment showed a significant increase in SBS when compared with the controls and MMA application (p < 0.0001). Adhesive failure type was observed in the control groups, which dramatically changed to cohesive or mixed in groups with surface treatment. The SBS of 3D-printed resin was decreased when compared with the conventional and CAD-CAM milled resin. Regardless of the material type, SB and MMA applications increased the SBS of the repaired resin and SB showed high performance.

Periodontal risk assessment in a teaching hospital population in Saudi Arabia's Eastern Province.

OBJECTIVE: With this cross-sectional study, we aimed to evaluate factors associated with moderate and high risk of periodontal disease (PD) progression in the Saudi population. METHODS: We reviewed 281 patients' clinical charts from predoctoral periodontal clinics at the dental teaching hospital in the College of Dentistry (COD) at Imam Abdulrahman Bin Faisal University (IAU) in Dammam, Saudi Arabia. After obtaining ethical approval, we determined the Periodontal Risk Assessment (PRA) of the included patients based on the modified criteria developed by Lang and Tonetti (2003). We used logistic regression on stratified data and divided the results into two categories (low-moderate and high risk) to assess the effect modifier for potential risk factors. We used SPSS version 22 for data analysis, and considered a P-value ≤ 0.05 to be statistically significant. RESULTS: Out of the 281 patients, 104 (37.0%) were male and 177 (63.0%) were female, with a mean age of 39.9 ± 14.0 years; 78.1% were Saudi nationals, 77% were married, and 44.6% were in the age group of 30 to 49. The PRA revealed 86 (30.5%) to represent high risk, 108 (38.3%) denoted moderate risk, and 88 (31.2%) signaled low risk for periodontitis. Logistic regression analysis showed that males were three times more likely to have high PRA (OR = 3.24) and to be married (OR = 2.77), as well as to be active smokers (OR = 8.87). The highest predictive factors of high PRA were 8 or more pockets ≥ 5 mm (OR = 29.0), those with active diabetes mellitus (DM; OR = 10.2), and those with 8 or more missing teeth (OR = 9.15). CONCLUSION: Saudi males who are married and have residual periodontal pockets, are actively diabetic, and with missing teeth are at high risk of PD. Further research is needed with a larger sample size comparing the general population with and without PD.

The clinical implications of platelet-rich fibrin on periodontal regeneration: A systematic review.

OBJECTIVES: Platelet concentrates have been shown to enhance periodontal regeneration when used as a treatment on their own or in conjunction with bone grafting materials. This systematic review aims to assess the effects of using platelet-rich fibrin (PRF), both alone and in combination with other conventionally used materials, on periodontal regeneration in clinical trials. MATERIALS AND METHODS: A systematic electronic search was performed in the electronic databases MEDLINE (PubMed), Scopus, and Web of Science. Specifically, we searched for English language articles published between 2009 and 2019 that conducted in-human studies and included a summary of the results. Our primary search yielded 220 articles, and of these, 110 were clinical studies. Forty-four articles were then selected for a full reading. RESULTS: Twenty-six randomized control trials (RCTs) met the inclusion criteria and were included in this review. Despite the differences between the reviewed studies, most revealed the ability of PRF to promote periodontal wound healing. The positive effects of PRF were observed in clinical criteria, such as reductions in pocket probing depth (PD) and increases in clinical attachment level (CAL), as well as in the degree of defect bone fill, which was determined either radiographically or by surgical re-entry. CONCLUSIONS: Additional studies are needed to compare the clinical outcomes of various PRF application procedures and establish standardized protocols for treating periodontal disease with PRF.

Assessment of Mandibular Molar Root Morphology Using Cone­Beam Computed Tomography in Periodontitis Patients From Eastern Province: A Cross-Sectional Study.

Background The aim of this study was to assess the root morphology of mandibular molar teeth using cone­beam computed tomography (CBCT) in patients with periodontal disease. Methods In total, 88 patients were included in this study (70 patients with periodontitis and 18 patients with non-periodontitis). This cross-sectional study involved CBCT images taken for patients who visited the dental clinic of Imam Abdulrahman Bin Faisal University (IAU) from January 2019 to March 2021. The following data were analyzed on the mandibular molars: root length, number of root canals, root trunk, distance between roots, accessory canals in the furcation area (ACF), bone loss, and furcation involvement. Results The mesial root was longer than the distal root in the mandibular molars of periodontitis and non-periodontitis patients. A statistically significant difference was observed between non-periodontitis and periodontitis patients regarding the number of mesial root canals of the mandibular first molar; 70% had two root canals in non-periodontitis patients, compared with 86.1% in periodontitis patients (p = 0.04). First molars of non-periodontitis patients had significantly longer root trunks than periodontitis patients (4.65 ± 0.90 compared with 4.09 ± 1.02, p = 0.007). There was a statistically significant difference in bone loss between non-periodontitis and periodontitis patients (0% and 25% for first molars, and 2.8% and 23.6% for second molars, respectively). Accessory furcation canals were 2.9 % in second molars and 7.1 % in first molars in periodontitis patients, which were higher compared with non-periodontitis patients. Conclusions The first molar showed a longer root trunk in non-periodontitis patients than in periodontitis patients. The mean mesial and distal root lengths were also greater in the first than the second molar. Accessory canals in the furcation area were more observed in first molars than in second molars in periodontitis patients compared with non-periodontitis patients.