The Journal of Indian Prosthodontic Society最新文献

Aim: The study aimed to compare the flexural strength, fracture toughness, and impact strength of the denture base materials fabricated using dual-layer and bonded 3D printing techniques.

Settings and design: In vitro comparative study.

Materials and methods: Seventy-two bar-shaped samples were fabricated using a digital light processing 3D printer and were divided into 2 groups (n = 36 each). Group I samples were fabricated by dual-layer technique, with the denture base and tooth-colored resins were printed sequentially in a single print cycle. Group II samples were printed separately and bonded with denture base resin. Flexural strength and fracture toughness were tested according to ISO 20795-1:2013, and impact strength was evaluated using ASTM D-256.Statistical Analysis Used: Statistical analysis comprised Shapiro-Wilk for normality, t-test for flexural strength, and Mann-Whitney U-test for fracture toughness and impact strength (α = 0.05).

Results: Group I exhibited significantly higher flexural strength (82.78 ± 2.02 MPa) and fracture toughness (89.91 ± 0.53 MPa) compared to Group II (80.01 ± 2.69 MPa and 86.93 ± 2.29 MPa, respectively). Conversely, impact strength was greater in Group II (4.17 ± 0.39 J) than in Group I (3.00 ± 1.04 J) (P < .05).

Conclusion: The dual-layer printing technique improved the flexural and fracture resistance of denture base materials by eliminating interfacial weaknesses. Although bonded resins exhibited higher impact strength, the structural advantages of dual-printing support its application in clinical prosthodontics.

Aim: Immediate loading protocols are frequently applied when placing mini-implants (MIs), although many of these may not be functional loading. Data on immediately functionally loaded MIs are limited. Therefore, this systematic review aimed to answer the question: What is the survival rate (SR) of immediately functionally loaded MIs placed in the edentulous mandible to retain a complete mandibular overdenture?

Settings and design: Studies published in peer-reviewed journals up to April 2025 were considered.

Material and methods: An electronic search was conducted using MeSH terms and free-text search in April 2025 across Web of Science, PubMed, Cochrane Central, EBSCOhost, and ScienceDirect. Eligible criteria included case-control studies, retrospective and prospective case series, cohort studies, clinical trials, and randomized controlled trials.

Statistical analysis used: Not applicable.

Results: Out of 1854 identified references, seven studies met the inclusion criteria, three randomized controlled and four prospective case series. A total of 496 immediately functionally loaded MIs were placed in 124 patients. The diameters of MIs were 1.8, 2.0, 2.1, 2.2, and 2.4 mm. Within the 1st year, 16 out of 495 MIs failed, resulting in a 1-year SR of 96.77%. A 24-month SR of 94.4% was reported by three studies, and a 36-month rate of 94.77% was reported by two studies.

Conclusions: Current evidence indicates that immediately functionally loaded MIs are a promising option for retaining mandibular overdentures, with a high 1-year SR of 96.77%. However, the limited number of included studies and relatively short follow-up periods highlight the need for further well-designed, long-term research to validate these findings.

Aim: This study aimed to assess and compare the wear resistance of 3D printable crown and bridge interim resin material with two different 3D printers.

Settings and design: In vitro comparative study.

Materials and methods: 60 specimens were divided into 2 groups and designed using nx12 (Unigraphics) software. This Standard Tessellation Language file was used to print the specimens. Specimens fabricated using Phrozen Sonic Mini 3D printer of LCD software were grouped as Group A (n = 30), and specimens fabricated using Asiga Max 3D printer of DLP software were grouped as Group B (n = 30). Surface micro roughness measurements (Ra) were noted with a profilometer prior to and following toothbrush wear simulation. The collected data were tabulated to facilitate statistical analysis.

Statistical analysis used: Student's t-test and Mann-Whitney U-test was employed for multiple comparisions.

Results: The Student's t-test was employed to compare the mean surface micro-roughness of Group A and Group B specimens before and after toothbrush wear simulation. The test indicated that there was no significant difference.

Conclusion: Within the scope of this study, both groups underwent wear and were statistically insignificant.

Aim: This study aimed to evaluate the effects of build position (rows or columns) on the accuracy and flexural properties of three-dimensional printing resin model materials.

Settings and design: This was a comparative experimental study.

Materials and methods: Three additive manufacturing technologies - digital light processing (DLP), stereolithography (SLA), and polymer jetting printing (PJP) - were employed to fabricate resin model specimens (2 mm × 2 mm × 25 mm), arranged evenly in 7 rows and 7 columns on the build platform. Dimensional trueness was assessed by measuring deviations in length (X-axis), width (Y-axis), and height (Z-axis) using a digital micrometer. Triplicate printing runs were performed to determine precision, quantified using intraclass correlation coefficient analysis. Flexural properties were evaluated through three-point bending tests.

Statistical analysis used: Data were analyzed using one-way ANOVA followed by Tukey post hoc tests.

Results: The PJP group exhibited deviations in length (0.18-0.25 mm) and height (0.18-0.22 mm) at several column positions, exceeding 0.1 mm, whereas the DLP and SLA groups showed deviations in all dimensions within 0.1 mm. At different row positions, PJP length (0.20-0.24 mm) and height (0.17-0.22 mm) deviations also exceeded 0.1 mm. Precision in height was lower than in length or width across both rows and columns (P = 0.000). Compared with the DLP and PJP groups, the SLA group demonstrated larger deviations in flexural modulus at column positions (P = 0.003, H = 19.730) and greater variations (95% confidence interval) in flexural strength and modulus at column and row positions.

Conclusion: Build position had a greater influence on trueness in the PJP group, while precision was lowest for height across all three groups. Furthermore, the flexural strength and modulus of the SLA group varied more significantly with build position. Thus, meticulous selection of the build position is essential to achieve improved accuracy and flexural properties in resin models.

Aim: To evaluate and compare the shear bond strength between polyether ether ketone (PEEK) and maxillofacial silicone after cathodic arc plasma spraying and accelerated aging.

Settings and design: An in vitro study.

Materials and methods: According to ISO 10477:2020, 72 PEEK specimens were fabricated using computer-aided design/computer-aided manufacturing with 10-mm diameter and 3-mm thickness, and the silicone specimens were made with 5-mm diameter with 2.5-mm height. The specimens were categorized into Group 1 - No surface treatment, Group 2 - Cathodic arc plasma spraying, and Group 3 - Primer application. The silicone specimens were bonded to PEEK and subjected to accelerated aging for 252 and 504 h. The shear bond strength was performed using a universal testing machine at 1 mm/min crosshead speed.

Statistical analysis used: One-way ANOVA, Tukey HSD test, and Student's t-test, where P < 0.5 was set as significant.

Results: PEEK specimens subjected to primer application exhibited highest shear bond strength of 19.22 ± 0.35 Mpa, 18.55 ± 0.60 Mpa, 18.14 ± 0.65 Mpa, followed by cathodic arc plasma spraying 14.71 ± 0.28 Mpa, 13.54 ± 0.42 Mpa, 12.46 ± 0.48 Mpa after 24 h of fabrication, 252 h, and 504 h of aging and the least shear bond strength exhibited by control 4.98 ± 0.32, Mpa, 4.52 ± 0.33 Mpa, 4.2 ± 0.39 Mpa, respectively. The significance value P = 0.0001, which was <0.05. Hence, the results were found to be statistically significant.

Conclusion: The maximum shear bond strength between PEEK and maxillofacial silicone was seen after primer application, followed by cathodic arc plasma surface treatment. Increasing the aging hours from 252 to 504 h, the shear bond strength was relatively reduced between PEEK and maxillofacial silicone.

Aim: Polymethyl methacrylate (PMMA) is a widely used denture base material, but its mechanical and antimicrobial properties require further improvement to the diverse clinical situations. Nanoparticles such as zinc oxide (ZnO) and polylactic acid (PLA) offer promising enhancements through improved structural and functional integration. The aim of the study was to assess the molecular characterization and structural integration of PMMA modified with nano-ZnO and nano-PLA.

Settings and design: This was an in vitro material characterization study.

Materials and methods: Forty samples were fabricated and divided into two groups: control (n = 20, unmodified PMMA) and test (n = 20, PMMA reinforced with 10% nano-PLA and 3% ZnO). A high-shear mixing technique was used. Molecular interactions were evaluated using Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDS) estimated the nanoparticle dispersion and elemental composition.

Statistical analysis used: Qualitative analysis was used for statistical analysis.

Results: FTIR confirmed the inclusion of nano-PLA and nano-ZnO, with a broad absorption peak at 3500 cm-1 indicating increased polarity and hydrogen bonding. EDS analysis verified the presence of carbon, oxygen, and zinc, with uniform nanoparticle dispersion. Nano-PLA addition reduced crystallinity and nano-ZnO promoted crystal formation, indicating their functions in structural modification.

Conclusion: The study confirmed molecular interactions and uniform elemental dispersion, with indications of reduced crystallinity. These findings suggest potential for further investigations into the mechanical and antimicrobial properties of this modified resin for clinical applications.

Aim: This study aimed to compare and evaluate the fracture toughness and antifungal properties of polymethyl methacrylate (PMMA) and polyether etherketone (PEEK) materials incorporated with titanium dioxide nanoparticles at two different concentrations (2% and 3%).

Settings and design: A total of 42 PMMA specimens and 42 PEEK specimens were fabricated, with each group consisting of 7 specimens and a total of 6 groups, and each group was subjected to tests for fracture toughness and antifungal property.

Materials and methods: The PMMA specimens were fabricated by incorporating TiO2 nanoparticles in 2 and 3 percentages into the polymer, followed by making the specimens in the lost wax technique, and PEEK specimens were fabricated by incorporating the nanoparticles into the pellets in 2 and 3 percentages, followed by filament extrusion, and this filament was used for three-dimensional printing the specimens in required dimensions. Once the specimens were fabricated, these were tested for fracture toughness using urinary tract mycosis and antifungal properties using the green synthesis method. Later, statistical analysis was performed to determine the significance.

Statistical analysis used: Statistical analysis was done using IBM SPSS Statistics for Windows, Version 20.0. The Shapiro-Wilk test was applied to each group for assessment of data normality. One-way analysis of variance followed by Tukey's post hoc test was done.

Results: Fracture toughness of PMMA with 3% of TiO2 was highest among the PMMA group, being 1.62 ± 0.64 MPa m1/2 and PEEK with 3% of TiO2 is highest among the PEEK group being 4.91 ± 0.30 MPa m1/2 when compared to 0% and 2% groups. Similarly, for anti-Candida, the results were better in the group with 3% of TiO2 PMMA (154.86 ± 3.13 CFU/100 mL) and 3% of TiO2 PEEK (131.14 ± 2.73 CFU/100 mL) compared to other groups.

Conclusion: Both fracture toughness and anti-Candida properties were improved when incorporated with TiO2 nanoparticles, these properties enhanced as the concentration of nanoparticles increased within the limitations of the study.

Aim: Enhancing early cell-implant interaction is vital for successful osseointegration. This in vitro study aimed to evaluate the combined effect of photofunctionalization and low-frequency mechanical vibration on osteoblast cells derived from human placental tissue cultured on titanium surfaces.

Settings and design: Following approval from the Institutional Ethics Committee and informed consent, a controlled in vitro experimental study was conducted in the Department of Prosthodontics in collaboration with a certified cell culture laboratory.

Materials and methods: Osteoblast cells were isolated and cultured. Titanium implant surface was photofunctionalized using ultraviolet C (UV-C) light (254 nm) for 48 h. Cells were seeded onto the implant surface and divided into three groups: Group 1: Control (untreated titanium), Group 2: UV-treated titanium, and Group 3: UV-treated titanium implant with mechanical vibration (20 Hz for 3 min/day for 3 days) to osteoblast cells. Cell proliferation was assessed using MTT assay, mineralization via Alizarin Red S staining, and osteogenic gene expression (runt-related transcription factor-2, Alkaline phosphatase, OCN) through reverse transcription polymerase chain reaction.

Statistical analysis used: Data were analyzed using analysis of variance with Tukey's post hoc test (P < 0.05).

Results: The combination of photofunctionalization and mechanical vibration (Group 3) significantly enhanced cell proliferation, mineral deposition, and osteogenic gene expression compared to Groups 1 and 2 (P < 0.05). While photofunctionalization alone improved osteoblast activity, the synergistic application of mechanical vibration further amplified the response.

Conclusion: The combination of photofunctionalization and low-frequency vibration significantly enhances the osteogenic response of osteoblast cells to titanium, indicating its potential to improve implant osseointegration.

Integration of digital technology in prosthodontics enables precise and predictable outcomes. A hybrid digital-conventional workflow combines the accuracy of digital protocols with the reliability of traditional techniques. A 46-year-old male with generalized aggressive periodontitis required full-mouth extraction and immediate dentures. Intraoral scans were captured at the existing vertical dimension and used to design custom trays in EXOCAD. The trays, three-dimensional-printed with windows for natural teeth, facilitated border molding and final impressions for soft tissue capture. These impressions were digitized, superimposed on intraoral scans, and used to create a virtual model, perform virtual extractions, and fabricate definitive dentures. The digital approach improved patient comfort, accelerated planning, and enhanced accuracy, while conventional steps ensured an optimal peripheral seal in scanner-inaccessible areas. The technique delivered a functionally stable and esthetically satisfactory outcome.