Prosthesis, Volume 6, Issue 5 (October 2024) – 9 articles

The precision of the luting protocol plays a crucial role in the success and survival rate of porcelain laminate veneers (PLVs). This in vitro study aimed to evaluate the influence of different luting techniques on the positioning of PLVs through a novel, noninvasive, scanning-based technique. A total of 45 ceramic PLVs were milled and cemented on human tooth replicas. Specimens were divided into three groups of 15, each subjected to a different luting protocol: flowable composite (Group A), dual-cure resin cement (Group B), and preheated composite resin (Group C). After luting procedures, specimens were scanned, and every STL file was superimposed with the original tooth design in Geomagic Control X version 2022.1 software to assess linear (incisal, mid, cervical) and angular discrepancies. Statistical analysis was performed using one-way ANOVA, Tukey’s HSD tests, and regression analysis. ANOVA results showed no statistically significant differences for incisal (F = 0.327, p = 0.723), mid (F = 0.287, p = 0.752), cervical (F = 0.191, p = 0.827), and angular (F = 0.026, p = 0.975) measurements. Tukey’s HSD post hoc tests confirmed the lack of significant pairwise differences between groups. The study demonstrated that the type of luting agent used does not significantly impact the final position of PLVs. This suggests flexibility in the choice of luting agents without compromising the accuracy of PLV placement. Full article

Ceramic dental restorative materials have growing popularity, albeit their brittle and stochastic nature are acknowledged shortcomings that impact the prosthesis lifespan. The mechanical performance of ceramics is dominated by the constitutional microstructural and fracture toughness mechanisms, as well as externally applied triggers. Thus, there is ongoing expanding research in the sphere of ceramic material engineering and thermal refinement, addressing concerns regarding toughness, machinability, reliability, stainability, and biodegradation. While the current trend in dental ceramic manufacturing has transitioned from micrometric crystalline sizes to submicrometric and nanometric ranges, there is an unclear understanding of the microstructural implications on ceramic behaviour. Therefore, this review covers the comprehensive characterisation approaches commonly employed in the scientific literature to describe the multifaceted performance aspects as well as clinical-related prerequisites of dental ceramics. Moreover, updated standardised testing parameters and performance thresholds pertaining to ceramic mannerisms are described in an attempt to translate their clinical applicability. Full article

Zirconia crowns are capping materials used in dentistry for tooth capping and are very popular due to their optical properties and natural-looking visuals. In vitro aging protocols measure zirconia’s optical properties, which are vital in order for it to look natural. This study aims to conduct a systematic review to explore the effect of in vitro aging protocols on the optical properties and crystalline structure of high-translucency (HT) zirconia. A correlation matrix was obtained using Microsoft Excel, which was later transferred into SPSS for confirmatory factor analysis (CFA) and hierarchal clustering and to obtain a dendrogram in order to display the distribution of clusters for each key term relevant to the study. Further, for qualitative analysis, 17 studies were screened and reviewed. The result demonstrates that high translucency has been observed in the crystalline structure of zirconia capping. However, quantitative and qualitative results did not demonstrate the in vitro protocol; instead, neglect of the in vitro protocol’s vitality in zirconia crown capping was alarming. Overall, zirconia has good optical properties when combined with catalysts such as aluminum and lithium to obtain a more sustainable crystalline structure. Full article

This in vitro investigation aimed to compare the trueness, precision, internal fit, and marginal adaptation of Varseo Smile Crown Plus (VSCP), CROWNTEC (C), and milled Enamic crowns (E) using a 5-axis dental milling machine (prograMill PM7). 39 crowns (VSCP, E, C; n = 13) were designed and fabricated. Internal/marginal adaptation, precision, and trueness were assessed via die scans with/without a fit checker. Dimensional discrepancies were determined by superimposing the scans. One-way ANOVA (α = 0.05) analyzed the results. No significant differences were found in internal fit or marginal adaptation between groups. However, group E exhibited the best fit (axial: 82.9 µm). Trueness differed significantly (p < 0.05) across all groups and areas. Group E had the highest trueness (intaglio: 25.8 µm), while VSCP had the lowest (marginal: 31.9 µm). Precision varied significantly within the occlusal area of printed groups (highest for C: 17.8 µm) and the marginal area between printed/milled (VSCP vs. E) and C vs. E (lowest for E: 20.5 µm, highest for VSCP: 27.9 µm). In conclusion, both milled and 3D-printed crowns achieved comparable internal fit and marginal adaptation. However, group E displayed superior fit and trueness. While C exhibited higher occlusal precision, E had higher marginal precision. These findings suggest the potential for 3D-printed hybrid polymer crowns, warranting further investigation. Full article

Dissatisfaction among upper limb prosthetic users is high, reaching over 70%, and 52% of upper limb amputees abandon their prosthetic devices due to limitations such as limited functionality, poor design/aesthetic, and improper fit. The conventional procedure of making prosthetics is time-consuming and expensive. This study was conducted to provide an alternative solution for the several issues of current prosthetic devices. 3D printing technology offers a promising alternative, providing greater accuracy, reduced labor time, and improved fit and comfort. This research explores the application of 3D printing for creating custom silicone prosthetic fingers, using Fused Deposition Modelling (FDM) for the mold. A high-resolution 3D scanner was employed to capture the precise anatomy of the patient’s hand, and CAD software was used to design molds that satisfied the patient preference and were reusable. The resulting prosthetics demonstrated good fit and patient satisfaction, though exact color matching remains a challenge, but still, it did demonstrate that it is possible to fabricate colored prosthetics. Performance tests, such as the Jebsen–Taylor Hand Function Test, indicated that while initial performance with the prosthetic was slightly lower, patient satisfaction and potential for improved functionality over time were high. This study underscores the potential of 3D printing to enhance the customization, cost-effectiveness, and overall quality of prosthetic devices, contributing to Sustainable Development Goals related to health and industry innovation. Full article

Background: Nanocomposite resins have been widely used in modern denture manufacturing. However, their long-term color stability is a concern for both dental professionals and patients. Purpose: to evaluate the effect of different beverages on the color stability of 3D-printed denture base resins modified with zirconium dioxide nanoparticles (ZrO₂NPs). Methods: A total of 440 specimens were fabricated and distributed into 11 groups (n = 40/group). The control group of heat polymerized (PMMA) and five groups of two different 3D-printed resins (NextDent and ASIGA) as experimental groups with various concentrations of ZrO₂NPs added to the 3D-printed resins (0.5 wt%, 1 wt%, 3 wt%, 5 wt%) in addition to one unmodified group per resin. Specimens per group are sorted into four subgroups (n = 10) according to tested beverages, as follows: coffee, tea, cola, and mineral water. Before immersion, all the specimens were exposed to 5000 thermal cycles. Color changes (ΔE₀₀) were assessed prior (T0) and following immersion for 6 days (T1) and 12 days (T2) using a spectrophotometer. Color difference values were calculated by using CIEDE2000 color difference. Data was analyzed by ANOVA and post hoc Tukey test with a significant level of less than 0.05. Results: Tea produced the highest color change for both NextDent and ASIGA materials, whereas water caused the least color change on PMMA at T2. Increasing the immersion time resulted in more color changes, with tea and coffee showing significant differences. PMMA had considerably less color change than 3D-printed resins. The color change of 3D-printed increased after adding ZrO₂NPs. Conclusions: Beverage type and immersion time have an impact on the color stability of unmodified and ZrO₂NP-modified denture base resins with significant change after immersion in tea and coffee. Full article

Background: For optimal clinical outcomes in full mouth rehabilitations, it is vital to determine the optimal jaw relations and confirm the appropriate vertical dimension of occlusion (VDO). The current study aims to evaluate various facial measurements as an adjunct in determining VDO in dentate individuals. Methods: A total of one hundred and twenty subjects, sixty males and sixty females, of the age group 19-30 were selected for the study. VDO (chin–nose distance) and other facial measurements like the glabella to subnasion (G-S) distance, both right and left pupil to rima oris (P-R) distance, both right and left corner of mouth to outer canthus of eye (M-E) distance, and both right and left ear to eye (E-e) distance were measured using a Vernier caliper. Results: The mean ± standard deviation of the C-N distance, G-S distance, right P-R distance, right M-E distance, left M-E distance, right E-e distance, and left E-e distance were 67.70 mm ± 3.22 mm, 60.29 mm ± 3.67 mm, 65.99 mm ± 3.72 mm, 66.00 mm ± 3.91 mm, 69.51 mm ± 3.71 mm, 69.48 mm ± 3.68 mm, 69.59 mm ± 3.98 mm, and 69.51 mm ± 3.95 mm, respectively. Pearson’s correlation coefficient between the C-N distance and M-E distance was found to be 0.739 (right), 0.730 (left); that between the C-N distance and E-e distance was found to be 0.738 (right), 0.732 (left); that between the C-N distance and P-R distance was found to be 0.660(right), 0.670(left); and that between the C-N distance and G-s distance was found to be 0.417. Conclusions: The present study reported a high positive correlation between the chin to nose distance and the distance between both the right and left lateral corner of the mouth to the outer canthus of the eye, and the distance between both the right and left ear to the eye. Hence, these measurements can be used as an adjunct for establishing VDO in the edentulous patient. Full article

Objectives: To assess the overall mental health of enucleated or eviscerated patients after high-density porous polyethylene OCULFIT implantation and external prosthesis over a 1-year follow-up. Methods: Patients with an indication of enucleation or evisceration with OCULFIT implantation were included in a prospective study. The patients completed four questionnaires regarding mental health at three different visits (baseline, 3–6 months, and 9–12 months post-surgery). The questionnaires used were the following: SF-12 for multidimensional health-related quality of life (scale 0–100); Rosemberg self-esteem scale (scale 0–40); Patients Health Questionnaire-4 (PHQ-4) (scale 0–6); and a Lifetime Major Depression and Anhedonia questionnaire (categorised in groups with/without symptoms). Results: A total of 33 patients (16 enucleations and 17 eviscerations) were included in the study. The physical domain of the SF-12 questionnaire did not change between visits, but the mental domain significantly improved from the baseline to the last visit (41.71 ± 12.72 vs. 46.80 ± 10.68, p = 0.04). The number of patients with high, moderate, and low self-esteem (Rosemberg scale) was similar between the baseline and the last visit. The depression and anxiety scores of the PHQ-4 were not significantly different among visits. The number of patients with no symptoms (depression or anhedonia) improved from the baseline (42.2%) throughout the follow-up (66.7% at the last visit). Conclusions: OCULFIT orbital implant and external prosthesis placement maintained and/or improved the quality of life related to mental health in eviscerated and enucleated eyes. The number of patients with no symptoms improved from the baseline throughout the follow-up. The patients’ self-esteem was already high before implantation and remained stable over the follow-up. Full article