International Journal of Prosthodontics最新文献

Purpose: To compare the clinical outcomes of metal-ceramic vs metal-acrylic resin implant-supported fixed complete denture prostheses (IFCDPs).

Materials and methods: An electronic literature database search was conducted in the CINAHL, EMBASE, PubMed, and Web of Science databases. Additionally, a manual search of the literature was performed. Studies conducted in edentulous human subjects comparing clinical outcomes of metal-acrylic resin IFCDPs to those of metal-ceramic IFCDPs were included if quantitative outcomes for the following variables were reported: implant failure, prosthetic failure, incidence of peri-implantitis, incidence of peri-implant mucositis, incidence of peri-implant mucosal recession, prosthetic complications, and any patient-centered outcomes. Data from included studies were pooled to estimate effect size.

Results: Five studies met the inclusion criteria. A quantitative analysis was possible for risk of implant failure, prosthesis failure, and incidence of peri-implantitis. Meta-analysis showed no statistically significant differences in the risk of implant or prosthesis failure between the two groups. However, meta-analysis showed a significantly greater risk of developing peri-implantitis at the implant level in the metal-acrylic group when compared to the metal-ceramic group (risk difference = 0.069; 95% CI = 0.028 to 0.06; P = .001; fixed-effects model). Furthermore, descriptive analysis of the literature indicated a higher incidence of other biologic complications such as peri-implant mucositis and peri-implant mucosal recession, as well as prosthetic complications such as abrasion and veneer fracture, in metal-acrylic resin IFCDPs compared to metal-ceramic IFCDPs.

Conclusion: The available evidence suggests that a higher incidence of biologic and prosthetic complications, including a higher risk of peri-implantitis, are present with metal-acrylic resin IFCDPs compared to metal-ceramic IFCDPs.

Purpose: This in vitro study was conducted to evaluate the marginal accuracy of all-ceramic onlay restorations and prototypes fabricated using additive and subtractive methods.

Materials and methods: Ten typodont first molars were prepared and scanned two times using two different scanners: ARCTICA AutoScan (KaVo Dental) and CEREC Omnicam (Dentsply Sirona). The two groups of virtual models were used to design two groups of virtual onlay restorations using two different CAD software (n = 10 each group) and exported in STL files. Each group of STL files was converted to physical onlay restorations and prototypes by using three different methods; these included two additive manufacturing techniques, stereolithography apparatus (SLA) and digital light processing (DLP), and one subtractive technique, e.max milling using the KaVo Everest system and the Dentsply Sirona inLab MC X5. A digital microscope was used to evaluate the marginal fit around the onlay restorations or prototypes on the typodont teeth.

Results: All evaluated groups showed mean marginal gaps between 59 and 84 µm. No statistically significant differences were found when comparing the marginal accuracy of onlay restorations fabricated by the subtractive method and onlay prototypes from the two additive methods, SLA (P = .70) and DLP (P = .21).

Conclusion: All the models evaluated produced marginal gaps within the reported acceptable clinical range. Thus, these subtractive and additive methods may be considered suitable for onlay restoration production.

Purpose: To investigate the fracture load of different veneers for monolithic single-unit fixed dental prostheses (FDPs) made of a novel potential framework material, polyphenylene sulfone (PPSU).

Materials and methods: The fracture loads of four PPSU frameworks with different veneers (manual polymer veneer with Ceramage Body A3B; prefabricated polymer veneer with Novo.lign; digital polymer veneer with Telio CAD; digital ceramic veneer with IPS Empress CAD) and a monolithic control group (PPSU, Gehr) were examined initially and after 1,200,000 masticatory (50 N, 1.3 Hz) and 6,000 thermal cycles (5°C/55°C). Fracture analysis was performed using light microscope imaging. Fracture types were classified, and relative frequencies were determined. Univariate analysis of variance, post hoc Scheffé, partial eta squared, Kruskal-Wallis test, and Weibull moduli using the maximum likelihood estimation method were calculated. The defined level of significance was adjusted by Bonferroni correction (P < .005).

Results: Aging did not affect the fracture load values. Single-unit FDPs with a digital ceramic veneer showed lower values than monolithic and manual polymer-veneer specimens. Single-unit FDPs with a prefabricated and digital polymer veneer were in the same value range as specimens with a manual polymer and digital ceramic veneer. No differences were observed between manual polymer veneer and monolithic single-unit FDPs. All veneered specimens showed a fracture of the veneer. For monolithic single-unit FDPs, a plastic deformation was observed.

Conclusion: Veneered and monolithic PPSU showed sufficient fracture load values to indicate successful clinical use in single-unit FDPs. The choice of veneering method and material may play a minor role.

Purpose: To evaluate 1-year survival and success rates of 6-mm short implants placed in mandibular molar sites with two different abutments (dome/ball) retaining existing removable partial dentures (RPDs).

Materials and methods: In 19 patients, 38 implants of 6-mm length were placed bilaterally. After 4 months, each participant received the dome abutment, which 2 months later was exchanged with the ball abutment. Clinical data were recorded at abutment connection (4 months postsurgery) and at 6 and 12 months postsurgery, including probing depth, bleeding on probing, presence of plaque, and standardized radiographs. Implant success was assessed using the following criteria: presence of pain, mobility, radiographic bone loss, probing depth, and the presence of exudate. For descriptive analyses, mean and SD values were calculated. Paired sample t tests and linear regressions with a significance level of α < .05 were applied to analyze the evolution of peri-implant parameters and the influence of implant placement depth.

Results: The overall mean marginal bone level alteration (DMBL) was 1.05 ± 0.69 mm. A statistically significant marginal bone loss over time was observed at the mesial and distal aspects of all implants (P < .05). The implant survival rate was 100%. No implants showed pain, exudate, mobility, or probing depth > 7 mm. Three implants were classified as having satisfactory survival due to a DMBL > 2 mm (resulting success rate: 92.1%). No influence of implant placement depth was found.

Conclusion: These short-term results suggest that short implants can be used in mandibular molar sites for additional posterior support of free-end RPDs. However, in individual cases, DMBL > 2 mm may occur.

Patients with a facial malformation due to a cleft lip and palate (CLP) usually suffer from a reduced ability to function normally associated with a poor oral health-related quality of life. This condition often requires multiple significant surgical interventions, and the prosthetic restoration, when needed, is not always included in the initial treatment plan. In order to obtain the highest possible degree of functional, occlusal, and phonetic performance, as well as esthetics, a facially guided prosthodontic treatment sequence should be established. The case presented in this publication shows a multidisciplinary approach for reconstruction of a compromised maxilla with an implant-supported prosthesis via a minimally invasive, digitalized approach.

Purpose: To compare the production efficiency of selective laser sintering (SLS) to traditional casting for the fabrication of metal prosthodontic frameworks in a prospective pilot evaluation in a hospital prosthodontic laboratory setting.

Materials and methods: The time taken to complete each of the identified stages in the production of 50 removable partial denture frameworks made using either SLS (n = 25) or casting (n = 25) workflows was measured. The mean time for production was calculated for each workflow, and the difference was tested for statistical significance.

Results/conclusion: The results indicate that an SLS workflow may be more time-efficient, and further cost-effectiveness research is indicated.

Purpose: To investigate the discoloration and surface properties of four CAD/CAM composite resins following storage in various food solutions and exposure to cigarette smoke.

Materials and methods: A total of 74 specimens (N = 370) were prepared for five materials: Brilliant Crios (BC), Cerasmart (GC), Lava Ultimate (LU), Shofu Block HC (SH), and Sonic Fill 2 (SO). Discoloration (ΔE) was investigated with a spectrophotometer. Measurements were taken before immersion in storage media (carrot juice, curry, cigarette smoke, red wine, energy drink, and distilled water), after 2 weeks of immersion, and after manual polishing of the specimens following immersion. The average surface roughness (Ra) was measured with a profilometer. Qualitative surface observation was performed with scanning electron microscopy (SEM). Data were analyzed using Kolmogorov-Smirnov test, Mann-Whitney U test, and one-way ANOVA with Tukey post hoc test.

Results: The highest influence on ΔE after immersion was observed for storage medium (ηη_P² = 0.878, P < .001), followed by the interaction between storage medium and material (η_P² = 0.770, P < .001) and material (η_P² = 0.306, P < .001). For ΔE after polishing, the highest influence was indicated by the interaction between material and medium (η_P² = 0.554, P < .001), followed by medium (η_P² = 0.244, P < .001) and material (η_P² = 0.196, P < .001). Immersion in carrot juice led to the highest color change (ΔE: 8.0 to 10.4), whereas the lowest values were recorded in distilled water (ΔE: 2.0 to 2.4). Carrot juice and the energy drink caused the highest Ra values (0.120 μm to 0.355 μm). SEM pictures indicated a loss of the organic matrix after manual polishing.

Conclusion: The different materials reacted dissimilarly to the various storage media in terms of discoloration. Surface roughness increased after immersion or polishing. Neither discoloration nor surface roughness could be reset to default by manual polishing. Int J Prosthodont 2023;36:194-202. doi: 10.11607/ijp.6950.

Purpose: To compare the effect of office, home, and internal bleaching on the shear bond strength (SBS) of enamel to porcelain laminate veneers.

Materials and methods: A total of 36 extracted maxillary central incisors were randomly assigned to four groups: (1) no bleaching (control); (2) office bleaching with 40% hydrogen peroxide (HP); (3) home bleaching with 15% carbamide peroxide; and (4) intracoronal bleaching with sodium perborate (SP) using the walking bleaching technique. All teeth were separately immersed in artificial saliva for 14 days. The enamel surface was then reduced by 0.5 mm, and IPS e.max Press ceramic discs were bonded using a resin cement. After 24 hours, all specimens were thermocycled (5,000 cycles, 5°C to 55°C). The SBS was measured using a universal testing machine, and the failure mode was determined using a stereomicroscope. One-way ANOVA and Tukey honest significant difference tests were used for data analysis (P < .05).

Results: A significant difference was noted among the groups (P < .001). The highest SBS was noted in the control group (15.71 ± 5.39 MPa). The mean SBS in the office bleaching group (12.30 ± 4.64 MPa) was almost the same as the control. The lowest mean SBS belonged to the home bleaching group (5.39 ± 3.99 MPa). The mode of failure was adhesive in all four groups.

Conclusion: If bleaching is intended to be followed by porcelain veneers, the office bleaching technique with 40% HP is recommended. Delaying the bonding procedure for 2 weeks does not appear to be effective with home or intracoronal bleaching.

Purpose: To investigate and analyze the effects of different prosthetic protocols under different loading and occlusal conditions on the survival rates of single implants immediately placed into fresh extraction sockets of maxillary or mandibular premolars with single-stage surgery.

Materials and methods: Patients needing replacement of a single premolar in the maxilla or mandible were included and randomly divided into three groups based on the different loading protocols: group 1 = healing abutment; group 2 = provisional crown left out of occlusion without functional loading; and group 3 = provisional crown in functional occlusion in maximum intercuspation without contact in excursions. The hypothesis was that single implants inserted into fresh extraction sockets and immediately connected to a temporary crown under functional loading would demonstrate survival rates comparable to single implants placed in the same conditions connected to a healing abutment or to an immediate temporary crown left out of occlusion.

Results: A total of 112 patients were treated, and 126 implants were placed (92 in the maxilla and 34 in the mandible). After a mean follow-up of 2.5 years (range 1 to 5 years), there were no failures in groups 1 or 2. Two implants failed in group 3 (one in the maxilla, one in the mandible). The cumulative survival rate was 98.5% across all groups, with 100% in groups 1 and 2 and 95% in group 3. Statistical analysis showed that group 3 displayed a survival rate comparable to groups 1 and 2 (P = .08).

Conclusion: Within the limitations of this study, no significant differences were found in terms of implant survival rates between implants inserted into fresh extraction sockets without loading vs with immediate nonfunctional or functional loading. Int J Prosthodont 2023;36:161-171. doi: 10.11607/ijp.7518.

Purpose: To investigate microtensile bond strength and characterization with the novel lithium disilicate coating technique compared to conventional air abrasion.

Materials and methods: Eight zirconia blocks were fabricated and assigned to two groups (n = 4 each): (1) Lithium disilicate coating followed by hydrofluoric acid etching and Monobond N Primer (LiDi group); and (2) alumina air abrasion (MUL group). For each group, two identically pretreated zirconia blocks were bonded together with Multilink Speed Cement and cut into 30 stick-shaped specimens (1 × 1 × 9 mm3). The 120 specimens were stored in water for 24 hours and assigned to one of three groups (n = 20/group): (1) short-term storage for 24 hours; (2) thermocycling for 5,000 cycles; and (3) thermocycling for 10,000 cycles. A microtensile bond strength test was performed and evaluated. The bond strength results were analyzed using two-way ANOVA followed by one-way ANOVA and Tukey HSD (α = .05). Energy-dispersive x-ray spectroscopy (EDS), Fourier-transform infrared (FTIR), x-ray diffraction (XRD), focused ion beam scanning electron microscopy (FIB-SEM), and scanning electron microscopy (SEM) were used for chemical, crystalline phase, and failure mode analyses.

Results: The MUL groups recorded higher bond strength than the LiDi groups. Thermocycling significantly decreased the bond strength in both groups. Chemical analyses suggested that the lithium disilicate layer underwent hydrolysis, which compromised long-term bond strength.

Conclusion: The bond between composite cement and alumina-abraded zirconia performed better than that with the lithium disilicate coating technique. Int J Prosthodont 2023;36:172-180. doi: 10.11607/ijp.6744.