Journal of Advanced Prosthodontics最新文献

Purpose: This study evaluated the reliability of the chair-side CAD-CAM surgical guide (CSG) in the anterior maxilla by comparing its accuracy with the laboratory 3D-printed surgical guide (3DSG) and manual surgical guide (MSG) concerning different levels of dentists' surgical experience.

Materials and methods: Ten surgical guides of each type (MSG, 3DSG, and CSG) were fabricated on a control study model with missing right and left central incisors. Sixty implants were placed in 30 study models by two dentists (one inexperienced and one experienced) using three different types of surgical guides. Horizontal deviations at shoulder and at apex, vertical, and angular deviations were measured after superimposing the planned and placed implant positions in the software. Kruskal-Wallis and Mann-Whitney U tests were used to compare the accuracy of three types of surgical guides in each dentist group and the accuracy of each surgical guide between two dentists (α = .05).

Results: There were no significant differences in any deviations between CSG and 3DSG, apart from angular deviation, for both dentists' groups. Moreover, both CSG and 3DSG showed no significant differences in accuracy between the two dentists (P > .05). In contrast, MSG demonstrated significant differences from CSG and 3DSG and a significant difference in accuracy between the two dentists (P < .05).

Conclusion: CSG provides superior accuracy to MSG in implant placement in the maxillary anterior region and is comparable to 3DSG at different levels of surgical experience, while offering the benefits of shorter manufacturing time and reduced patient visits.

Purpose: This study aimed to assess and compare the color stability, flexural strength (FS), and surface roughness of occlusal splints fabricated from heat-cured acrylic resin, milled polymethyl methacrylate (PMMA)-based resin, and 3D-printed (PMMA) based-resin.

Materials and methods: Samples of each type of resin were obtained, and baseline measurements of color and surface roughness were recorded. The specimens were divided into three groups (n = 10) and subjected to distinct aging protocols: thermomechanical cycling (TMC), simulated brushing (SB), and control (without aging). Final assessments of color and surface roughness and three-point bending test (ODM100; Odeme) were conducted, and data were statistically analyzed (2-way ANOVA, Tukey, P <.05).

Results: Across all resin types, the most significant increase in surface roughness (Ra) was observed after TMC (P < .05), with the 3D-printed resin exhibiting the lowest Ra (P < .05). After brushing, milled resin displayed the highest Ra (P < .05) and greater color alteration (ΔE₀₀) compared to 3D-printed resin. The most substantial ΔE₀₀ was recorded after brushing for all resins, except for heat-cured resin subjected to TMC. Regardless of aging, milled resin exhibited the highest FS (P < .05), except when compared to 3D-printed resin subjected to TMC. Heat-cured resin exposed to TMC demonstrated the lowest FS, different (P < .05) from the control. Under control conditions, milled resin exhibited the highest FS, different (P < .05) from the brushed group. 3D-printed resin subjected to TMC displayed the highest FS (P < .05).

Conclusion: Among the tested resins, 3D-printed resin demonstrated superior longevity, characterized by minimal surface roughness and color alterations. Aging had a negligible impact on its mechanical properties.

Purpose: This study aims to evaluate the effects of exposure energy on the lateral resolution and mechanical strength of dental zirconia manufactured using digital light processing (DLP).

Materials and methods: A zirconia suspension and a custom top-down DLP printer were used for in-office manufacturing. The viscosity of the suspension and uniformity of the exposed light intensity were controlled. Based on the exposure energy dose delivered to each layer, the specimens were classified into three groups: low-energy (LE), medium-energy (ME), and high-energy (HE). For each energy group, a simplified molar cube was used to measure the widths of the outline (X_o and Y_o) and isthmus (X_i and Y_i), and a bar-shaped specimen of the sintered body was tested. A Kruskal-Wallis test for the lateral resolution and one-way analysis of variance for the mechanical strength were performed (α = .05).

Results: The zirconia green bodies of the ME group showed better lateral resolution than those of the LE and HE groups (both P < .001). Regarding the flexural strength of the sintered bodies, the ME group had the highest mean value, whereas the LE group had the lowest mean value (both P < .05). The ME group exhibited fewer agglomerates than the LE group, with no distinctive interlayer pores or surface defects.

Conclusion: Based on these findings, the lateral resolution of the green body and flexural strength of the sintered body of dental zirconia could be affected by the exposure energy dose during DLP. The exposure energy should be optimized when fabricating DLP-based dental zirconia.

Purpose: The aim of this study was to investigate the mechanical properties of three-dimensional (3D) printed denture base resin incorporating microcapsules containing plant essential oils.

Materials and methods: Denture base specimens containing up to 3% w/v essential oil microcapsule powders (MCPs), i.e., eucalyptus, geranium, lavender, menthol, and tea tree, in two resins (Detax and NextDent 3D+) were 3D printed using two printers (Asiga and NextDent 5100). The dispersion and interaction of the MCPs in the resin were assessed by SEM while the mechanical properties of the incorporated denture base including flexural strength (MPa), flexural modulus (MPa), Vickers hardness (VHN), and surface roughness (Ra) were also subsequently evaluated. Statistical analysis of any differences in mean values was determined using a two-way ANOVA with Tukey's post hoc testing (α = .05).

Results: The spherical shape of the MCPs was maintained during the mixing and polymerization/printing process. However, the Detax-Asiga group showed significant agglomeration of the MCPs even at the lowest MCP concentration levels (0.5% w/v). Overall, as the microcapsule concentration increased, the mean flexural strength decreased, though the menthol MCP groups remained compliant with the ISO standard. The flexural modulus and harness remained relatively unchanged, and the flexural modulus complied with the ISO standard regardless of the MCP concentration. Surface roughness increased with the addition of the MCPs but also remained below that required for clinical acceptance.

Conclusion: Incorporation of microencapsulated plant essential oils into 3D printed denture base resin was successfully achieved. While incorporation negatively influenced flexural strength and surface roughness, little effect on flexural modulus and Vickers hardness was demonstrated.

Purpose: The purpose of this study was to determine the effect of the connector configuration on the fracture load in conventional and translucent zirconia of three-unit fixed dental prostheses (FDPs).

Materials and methods: Six different three-unit FDPs were prepared (n = 6) from three types of zirconia (3Y-TZP (Katana ML^®), 4Y-TZP (Katana STML^®), and 5Y-TZP (Katana UTML^®)) in combination with two connector configurations (4 × 2.25, 3 × 3 mm). The Co-Cr master models were scanned, and the FDPs were designed and fabricated using CAD-CAM. The FDPs were cemented on the metal model and then loaded with a UTM at a crosshead speed of 1 mm/min until failure. Two-way ANOVA and Tukey's test were used for statistical analysis (α = .05).

Results: Fracture loads of 3Y-TZP (2740.6 ± 469.2 and 2718.7 ± 339.0 N for size 4 × 2.25 mm and 3 × 3 mm, respectively) were significantly higher than those of 4Y-TZP (1868.3 ± 281.6 and 1663.6 ± 372.7 N, respectively) and 5Y-TZP (1588.0 ± 255.0 and 1559.1 ± 110.0 N, respectively) (P < .05). No significant difference was found between fracture loads of 4Y-TZP and 5Y-TZP (P > .05). The connector configuration within 9 mm² was found to have no effect on the fracture loads on all three types of zirconia (P > .05).

Conclusion: Fracture loads of three-unit FDPs were affected by the type of zirconia. The fracture loads of conventional zirconia were higher than those of translucent zirconia. However, it was not affected by the connector configuration when the connector had a cross-sectional area of 9 mm².

Purpose: This in vitro study aimed to evaluate the performance of digital intraoral scanners in a completely edentulous patient with angled and parallel implants.

Materials and methods: A total of 6 implants were placed at angulations of 0°, 5°, 0°, 0°, 15°, and 0° in regions #36, #34, #32, #42, #44, and #46, respectively, in a completely edentulous mandibular polyurethane model. Then, the study model created by connecting a scan body on the implants was scanned using a model scanner, and a 3D reference model was obtained. Three different intraoral scanners were used for digital impressions (PS group, TR group, and CS group, n = 10 in each group). The distances and angles between the scan bodies in these measurement groups were measured.

Results: While the Primescan (PS) impression group had the highest accuracy with 38 µm, the values of 104 µm and 171 µm were obtained with Trios 4 IOSs (TR) and Carestream 3600 (CS), respectively (P = .001). The CS scanner constituted the impression group with the highest deviation in terms of accuracy. In terms of dimensional differences in the angle parameter, a statistically significant difference was revealed among the mean deviation angle values according to the scanners (P < .001). While the lowest angular deviation was obtained with the PS impression group with 0.185°, the values of 0.499° and 1.250° were obtained with TR and CS, respectively. No statistically significant difference was detected among the impression groups in terms of precision values (P > .05).

Conclusion: A statistically significant difference was found among the three digital impression groups upon comparing the impression accuracy. Implant angulation affected the impression accuracy of the digital impression groups. The most accurate impressions in terms of both distance and angle deviation were obtained with the PS impression group.

Purpose: This study aimed to compare the bite force (BF) between complete dentures and implant overdentures (IODs) retained by two mandibular implants. Additionally, we evaluated the quality of life (QoL) and patient satisfaction among individuals using IODs. In addition, the effects of demographic parameters such as age and sex, and clinical parameters such as implant length, implant diameter, attachment height, attachment color, and interimplant distance on BF, QoL, and patient satisfaction were evaluated.

Materials and methods: A total of 51 edentulous patients rehabilitated with the maxillary complete dentures and mandibular IODs retained by two implants were included in this study. BF was measured using a force meter pre- and post-implant in the same patients. Oral health-related quality of life (OHRQoL) was assessed with the Oral Health Impact Profile (OHIP-14) and patient satisfaction was assessed with the Visual Analog Scale (VAS) questionnaires.

Results: It was found that BF values were statistically higher for IODs than complete dentures (P < .001). In terms of attachment height of the OHIP scores, there was a significant difference in the psychological disability and social disability domains (P < .05). When examining the change in patient satisfaction as a function of sex, it was found that mandibular retention satisfaction differed significantly by sex (P < .05), but there was no significant difference in the other domains.

Conclusion: Within the limitations of this study, it was observed that the BF increased after the use of IODs. Several factors, including age, interimplant distance, attachment height, and attachment color, were found to impact OHRQoL. Sex and implant diameter were identified as factors affecting patient satisfaction.

Purpose: The aim of this study was to evaluate the reliability of implant stability measuring devices depending on the location of the implant and the position of the patient.

Materials and methods: Six implants were installed in different dentate sextants of six artificial bone models. Implant stability was measured in three conditions of the bone model (without mounting on a phantom head, mounted on a phantom head in supine position, and mounted on a phantom head in upright position). A resonance frequency analysis device (Osstell) and two damping capacity analysis devices (Periotest and Anycheck) were used to measure implant stability. The values measured outside the phantom head were treated as controls, and the values inside the phantom head were compared using an independent t-test.

Results: Osstell showed different results in two of the six divisions in both the supine and upright positions compared to outside of the mouth (P < .05). Periotest showed different results in all six parts in the supine position and in five parts in the upright position compared to outside of the mouth (P < .05). While Anycheck showed different results in five areas in the supine position compared to outside of the mouth, it showed different results in only one area in the upright position (P < .05).

Conclusion: In the difficult implant position for the operator to access, the implant stability measuring devices show less reliability. The accessibility of implant is greatly affected in the order of Osstell, Anycheck, and Periotest.