Influence of attaching mechanical retentive devices onto frameworks on fracture resistance of implant-supported zirconia crowns.

This study investigated the fracture load of implant-supported zirconia crowns (IZCs), in which indirect composite resin or feldspathic porcelain was layered onto zirconia frameworks with mechanical retentive devices. Three different zirconia frameworks were assessed: attaching mechanical retentive devices on glaze and opaque porcelain materials (GL and OP groups, respectively), and no attaching mechanical retentive devices (ND group). The frameworks were layered using feldspathic porcelain (FP veneer) and indirect composite resin (IC veneer). Fracture load of the specimens was measured. In FP veneer, the GL group recorded the highest fracture load. In the IC veneer, the GL and OP groups had significantly higher fracture load than the ND group. The fracture resistance of IZCs can be enhanced by applying glaze material before attaching mechanical retentive devices for porcelain layering. The mechanical retentive devices effectively yielded mechanical interlocking between the zirconia frameworks and the IC veneer in GL and OP groups.

Influence of different convergence angles of abutment teeth and cement spaces on internal adaptation of anterior CAD-CAM fixed dental prostheses.

PURPOSE: The aim of this study was to investigate the influence of different convergence angles of abutment teeth and different cement spaces on internal adaptation of anterior fixed dental prostheses (FDPs) fabricated with a computer-aided design-computer-aided manufacturing (CAD-CAM) system. METHODS: Composite resin FDPs for 99 standardized maxillary central incisors were fabricated according to nine parameters: three total convergence angles (4 [DG4], 12 [DG12], and 20 degrees [DG20]) and three cement space settings (10 [CS10], 50 [CS50], and 90 µm [CS90]). Internal space values were measured with a cement space replica technique. The Kruskal-Wallis and Steel-Dwass tests were used to evaluate differences in the total convergence angles and luting agent spaces, respectively (α = 0.05). RESULTS: For all three cement spaces tested, the median marginal gap values between abutment teeth and FDPs decreased significantly as the total convergence angle increased (P < 0.05). For the CS10 and CS50 groups, the internal space values at the axial area increased significantly as the total convergence angles increased (P < 0.05). CONCLUSION: Total convergence angles of the abutment teeth and cement spaces affected the marginal and internal adaptation of anterior FDPs fabricated with a CAD-CAM system.

Clinical performance of laminate veneers: A review of the literature.

PURPOSE: This narrative review aimed to survey the clinical outcomes of laminate veneers (LVs), including their survival and success rates. STUDY SELECTION: An electronic search of MEDLINE/PubMed, Web of Science, Cochrane Library, and Google Scholar from 2000 to April 2023 was conducted using the keywords "laminate" OR "veneer" OR "porcelain" OR "feldspathic" OR "lithium disilicate" OR "composite resin" OR "zirconia" OR "survival" OR "success." Case reports, case series, reviews, abstracts, in vitro studies, and observational studies were excluded. Five researchers independently evaluated the titles and abstracts of all identified studies. RESULTS: A total of 55 studies were identified. None of the studies met the criteria for zirconia LVs. According to the studies in this review, LVs fabricated with feldspathic porcelain, leucite-reinforced glass ceramics (LRG), and lithium disilicate ceramics (LDS) exhibited satisfactory survival and success rates. Furthermore, hydrofluoric acid etching followed by silane priming of the surface of ceramic LVs is necessary for improved clinical outcomes. The extent of dentin exposure significantly decreases the success rate of ceramic LVs. An appropriate adhesive luting process is required to achieve the long-term success of ceramic LVs. Dentin exposure should be minimized or sealed during tooth preparation to achieve a reliable and durable bond between LVs and abutment teeth. CONCLUSIONS: Based on this narrative review of the literature, the use of silica-based ceramic feldspathic porcelain, LRG, and LDS is recommended for LVs.

Influence of an internal firing of feldspathic porcelain before or after sintering on adaptation of high-translucent zirconia laminate veneers.

The aim of the present study was to evaluate the influence of two different internal surface treatments, namely, the firing of feldspathic porcelain before or after zirconia sintering, on the marginal and internal adaptation of laminate veneers (LVs) made of high-translucent zirconia. A total of 33 zirconia LVs were fabricated using a CAD/CAM system and divided into three groups based on the internal surface treatment method: the pre-firing (PRE) group involved firing feldspathic porcelain before zirconia sintering, the post-firing (POS) group involved firing feldspathic porcelain after zirconia sintering, and the no treatment (NT) group involved no application of feldspathic porcelain. The adaptation of the LVs was measured using a silicone replica technique. Data were analyzed using the Kruskal-Wallis and Steel-Dwass tests (α = .05). The POS group showed significantly higher marginal discrepancy values than the PRE group across all sites. The internal space values of the PRE groups were significantly lower than those of the NT group at all sites. The internal firing of feldspathic porcelain before zirconia sintering resulted in better marginal adaptation of the high-translucent zirconia LVs than the internal firing of feldspathic porcelain after zirconia sintering. The internal firing of feldspathic porcelain before zirconia sintering can achieve uniform internal adaptation of high-translucent zirconia LVs.

Fracture strength of implant-supported hybrid abutment crowns in premolar region fabricated using different restorative CAD/CAM materials.

The present study investigated the fracture strength of hybrid abutment crowns (HACs) in the premolar region that were fabricated with different restorative computer-aided design/computer-aided manufacturing (CAD/CAM) materials. The abutment-implant structures were randomly assigned into four groups (n=11 per group): bi-layered zirconia restorations (BL), translucent zirconia (4Y-PSZ) restorations (TZ), lithium disilicate ceramic restorations (LD), and dispersed nanoparticle-filled composite resin restorations (CM). All restorations were adhesively bonded to the titanium abutments. After the restoration-abutment complex was tightened onto the implant, the fracture strength was measured. The TZ (2.06 kN) and LD (1.87 kN) groups had significantly higher median fracture strengths than the BL (1.12 kN) and CM (1.10 kN) groups. In terms of fracture resistance, the 4Y-PSZ and lithium disilicate ceramic monolithic restorations would be superior to bi-layered 3Y-TZP and composite resin monolithic restorations for HACs in the premolar region.

Asymptomatic Fungemia Due to Rhodotorula spp. Caused by a Subcutaneously Implanted Central Venous Port Catheter.

A 66-year-old man was admitted to our hospital for gastrointestinal perforation. He had a history of surgery and chemotherapy for colorectal cancer and had a subcutaneously implanted central venous port catheter. After surgery for gastrointestinal tract perforation, he developed an intra-abdominal abscess, which was treated with broad-spectrum antimicrobial agents and improved. Following this improvement, Rhodotorula spp. was detected in a blood culture and at the catheter tip. He was asymptomatic despite having fungemia. His condition improved after the removal of the catheter and the administration of antifungal drugs. Fungemia due to Rhodotorula spp. is rare, and asymptomatic fungemia is even rarer.

2D-shear wave elastography in the prediction of type II endoleaks after endovascular aneurysm repair.

PURPOSE: To evaluate the usefulness of 2D-shear wave elastography (2D-SWE) in the prediction of type II endoleaks after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAA). MATERIAL AND METHODS: Twenty-nine patients underwent EVAR for AAA, and 2D-SWE was performed after EVAR. Follow-up contrast-enhanced CT and ultrasonography were performed to evaluate endoleaks in all patients. The median follow-up period was 12 months (range, 3-12 months). Patients were divided into two groups: one with an endoleak (endoleak group) and another without it (control group). We compared the elasticity index (EI) of intraluminal thrombus (ITL) and fresh thrombus (FT) between the two groups. RESULTS: Type II endoleaks were confirmed in five of the 29 patients (endoleak group), and there were no endoleaks in the other 24 (control group). ILT was observed in 21 patients of the control group and in all patients of the endoleak group. There was a difference only in EI of ILT; the mean EI (± standard deviation) of ILT was 89 ± 16 kPA in the control group and 113 ± 25 kPA in the endoleak group (p=.037). CONCLUSIONS: High EI of ILT may predict the occurrence of type II endoleaks after EVAR of AAA.

Clinical outcomes of single crown restorations fabricated with resin-based CAD/CAM materials.

Computer-aided design/computer-aided manufacturing (CAD/CAM) restorative materials have been widely used owing to a number of advantages, including stable quality of the materials, lower costs, and time-saving factors. Resin-based CAD/CAM materials for definitive restorations are classified into two groups: dispersed nanoparticle-filled composite resin and polymer-infiltrated-ceramic-network materials. Resin-based CAD/CAM materials have been applied to single crown restorations as a monolithic structure for the posterior region. In addition, resin-based CAD/CAM restorations have been applied recently for the anterior area. This literature review summarizes clinical outcomes, such as survival rates and clinical complications of single crown restorations fabricated with resin-based CAD/CAM materials.

Effect of luting agent type on fracture loads of implant-supported ceramic premolar prostheses.

To investigate the effect of luting agent type on fracture loads of implant-supported ceramic prostheses in premolar region. Ninety-nine implant-abutment complexes were divided into three different implant-supported prostheses: monolithic yttria-partially stabilized zirconia (Y-PSZ) restorations (MPZ specimens), porcelain layered on yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) restorations (PLZ specimens), and monolithic lithium disilicate ceramic restorations (MLD specimens). Implant-supported prostheses were luted with adhesive resin luting agent (RLA), glass ionomer cement (GIC), or zinc phosphate cement (ZPC). For MPZ and MLD specimens, fracture loads were significantly higher for RLA group than for GIC and ZPC groups. For PLZ specimens, fracture loads did not significantly differ in relation to luting agent. Fracture loads were significantly higher for MPZ specimens than for other test specimens, regardless of luting agent. Use of an adhesive resin luting agent is recommended for placement of premolar implant-supported monolithic Y-PSZ and lithium disilicate ceramic prostheses.

Fracture loads of screw-retained implant-supported zirconia prostheses after thermal and mechanical stress.

PURPOSE: The objective of the present study was to evaluate fracture loads of screw-retained implant-supported zirconia prostheses after artificial aging. METHODS: Four types of screw-retained implant-supported prostheses were fabricated (n=11 each); porcelain-veneered zirconia prosthesis (PVZ), indirect composite-veneered zirconia prosthesis (IVZ), porcelain-fused-to-metal prosthesis (PFM), and monolithic zirconia prosthesis (ML). The specimens were subjected to 10,000 thermocycles and cyclic loading for 1.2 million cycles. Fracture loads were measured, and the data were analyzed with the Kruskal-Wallis and Steel-Dwass tests (α=0.05). RESULTS: All specimens survived the artificial aging procedures. The fracture loads for the PVZ (1.52kN), IVZ (1.62kN), and PFM groups (1.53kN) did not significantly differ; however, the fracture load for the ML group (6.61kN) was significantly higher than those for the other groups. The fracture load for the IVZ group was comparable to those for the PVZ and PFM groups. CONCLUSIONS: The monolithic zirconia prostheses exhibited significantly higher fracture loads than the bilayered prostheses. All the investigated types of screw-retained implant-supported zirconia prostheses appear sufficient to resist posterior masticatory forces during long-term clinical use.

Effect of veneering materials on fracture loads of implant-supported zirconia molar fixed dental prostheses.

PURPOSE: To determine the effect of veneering material and framework design on fracture loads of implant-supported zirconia molar fixed dental prostheses (FDPs). METHODS: Sixty-six zirconia FDPs were manufactured onto two implants and classified as uniform thickness (UT) or anatomic design (AD). These framework design groups were then further divided into three subgroups (n=11): feldspathic porcelain-veneered zirconia FDPs (PVZ), indirect composite-veneered zirconia FDPs (IVZ), and metal-ceramic FDPs (MC). The FDPs were luted on the implant abutments and underwent fracture load testing. Significant differences were assessed by the Kruskal-Wallis test and Mann-Whitney U-test (α=0.05). RESULTS: For UT group, median fracture load was significantly higher for the IVZ (1.87kN) and MC (1.90kN) specimens than for the PVZ specimens (1.38kN) (p<0.05). In the AD group, the IVZ specimens had the highest median fracture load (4.10kN) of the three groups tested. The AD group exhibited higher median fracture loads than the UT group in all subgroups. CONCLUSIONS: Indirect composite appears to be a useful alternative to feldspathic porcelain as the layering material for implant-supported zirconia FDPs. The AD group had higher fracture loads than UT group. In addition, implant-supported indirect composite-veneered zirconia-based FDPs appear to be clinically feasible.

Effect of preparation design on marginal and internal adaptation of translucent zirconia laminate veneers.

This study investigated the effect of preparation design on the marginal and internal adaptation of laminate veneers (LVs) fabricated from translucent zirconia. Thirty-three resin teeth were prepared for LVs of three designs: window preparation (WP); incisal shoulder preparation (ISP); and incisal palatal chamfer preparation (IPP). Marginal adaptation was evaluated by measuring the vertical discrepancy between the LV margin and the finish line at 60 points. The internal adaptation was assessed by measuring the internal space width as the distance between the LV and the tooth at cervical, central, and incisal sites after sectioning. At the incisal, mesial, and distal sites, mean marginal discrepancies were significantly lower in the WP group than in the other two groups; the IPP group had the highest marginal discrepancies. At incisal sites, the median internal space was significantly higher in the IPP group than in the WP and ISP groups and higher in the ISP group than in the WP group. At the incisal site, marginal and internal adaptations were better for the non-overlap translucent zirconia LV design (WP) than for the overlap designs (ISP and IPP). The characteristics of the translucent zirconia LVs used in the present study indicate acceptable clinical performance.

An in vitro evaluation of fracture load of implant-supported zirconia-based prostheses fabricated with different veneer materials.

OBJECTIVES: The purpose of this in vitro study was to evaluate fracture loads of implant-supported zirconia-based prostheses fabricated with different veneer materials (resin-based material and lithium disilicate ceramics). MATERIAL AND METHODS: Forty-four zirconia-based molar prostheses were fabricated on dental implants and divided into four groups (n = 11): zirconia-based prostheses veneered with feldspathic porcelain (ZVF), zirconia-based prostheses bonded with the lithium disilicate glass-ceramic veneer (ZBD), zirconia-based prostheses veneered with indirect composite resin (ZVC), and zirconia-based prostheses bonded with composite materials fabricated from a CAD/CAM resin block (ZBC). The zirconia-based prostheses and abutments were adhesively bonded with a dual-polymerized resin-based luting material. Fracture load was determined using compression load to the prostheses with a universal testing machine. The data were analyzed with one-way analysis of variance (ANOVA) and Tukey's HSD test (α = .05). RESULTS: The mean fracture load was significantly higher in the ZBC group (3.95 kN) than in the ZVC group (3.28 kN). No significant difference in fracture load was found among the ZVF (3.52 kN), ZBD (3.48 kN), and ZVC groups. CONCLUSIONS: The adhesively bonded veneering technique enhances fracture resistance of implant-supported zirconia-based prostheses fabricated with a resin-based material. All implant-supported zirconia-based restorations tested should resist physiologic masticatory forces in the oral environment.

Additional Medical Costs Due to Hospital-Acquired Falls.

OBJECTIVES: To explore the additional medical costs (AMCs) due to hospital-acquired falls (falls), as well as their impact on clinical services within hospitals under the nationally uniform universal health insurance system in Japan. METHODS: With the use of administrative profiling data based on accounting systems linked with the Japanese social insurance medical fee schedule, we analyzed data from 2 teaching hospitals: Shimane University Hospital (SUH) and St. Mary's Hospital (SMH). We extracted 588 fall cases from 4669 incident reports in SUH and 1168 fall cases from 7717 incident reports in SMH that potentially incurred AMCs. RESULTS: Additional medical costs were 364 ± 2129 USD for minor injuries and 4336 ± 3645 USD for major injuries at SUH (P < 0.001) and 114 ± 124 USD for minor injuries and 2267 ± 2811 USD for major injuries at SMH (P < 0.001). Among the clinical services provided, imaging services were the most frequently used, with 89.9% (n = 205) of 228 minor injuries at SUH and 86.7% (n = 339) of 391 minor injuries at SMH; imaging services were used in all major injury cases at both hospitals. Although the number of cases using additional procedure/surgery services was lower than those using imaging services at both hospitals, AMCs for procedure/surgery services accounted for the highest proportions of total AMCs in both hospitals. CONCLUSIONS: Although falls with minor injuries outnumbered falls with major injuries, fall-related AMCs for the latter were higher at both teaching hospitals because procedure/surgery services were required for cases with major injuries such as femoral neck and trochanteric fractures. The findings suggest that hospital administrators and policy makers have to take appropriate measures to prevent major injuries inpatients due to hospital-acquired falls.

Multiparametric MRI for differentiation of borderline ovarian tumors from stage I malignant epithelial ovarian tumors using multivariate logistic regression analysis.

OBJECTIVE: To assess the value of contrast-enhanced MRI, apparent diffusion coefficient (ADC) measurement, and CA-125 measurement for differentiating borderline ovarian tumors (BOTs) from stage I malignant epithelial ovarian tumors (MEOTs). MATERIAL AND METHODS: This retrospective study included 43 patients with BOTs and 43 patients with stage I MEOTs who underwent contrast-enhanced MRI with DWI and CA-125 analysis. Two radiologists evaluated the MRI findings in consensus. Univariate and multivariate analyses were performed to detect the best predictor variables for MEOTs. RESULTS: Mixed cystic/solid and predominantly solid appearances, as well as thickened irregular septa, were more frequent in MEOTs. A papillary architecture and internal branching (PA&IB) pattern was more frequent in BOTs. MEOTs had thicker walls and septa, larger solid components, and higher CA-125 values. The mean ADC value of solid components (ADCmean) and minimum ADC value of whole lesions (ADCmin) were lower in MEOTs. Multivariate analysis revealed that ADCmin and maximum diameter of the solid components were independent indicators of MEOTs with an AUC, sensitivity, and specificity of 0.86, 81%, and 84%, respectively. CONCLUSION: ADCmin and maximum diameter of solid components were useful for differentiating BOTs from MEOTs.

Fracture resistance of implant-supported screw-retained zirconia-based molar restorations.

OBJECTIVES: The objective of this in vitro study was to investigate fracture loads of screw-retained zirconia-based molar restorations (hybrid abutment crown) fabricated with different restorative materials and designs. MATERIAL AND METHODS: Forty-four screw-retained zirconia-based molar restorations were fabricated on dental implants and divided into four groups (n = 11): porcelain-layered zirconia-based restorations (PLZ), indirect composite-layered zirconia-based restorations (ILZ), metal-ceramic restorations (MC), and monolithic zirconia restorations (MONO). The zirconia-based restorations in the PLZ, ILZ, and MONO groups were adhesively bonded on implant abutments with a dual-polymerized resin material. All restorations were tightened on implant bodies with titanium screws and were tested for fracture resistance. The Kruskal-Wallis test and Steel-Dwass test were used to evaluate differences in fracture loads (α = 0.05). RESULTS: As compared with the other groups, the MONO specimens had a significantly higher mean fracture resistance (7.54 kN); no significant differences were found among the PLZ (1.96 kN), ILZ (1.80 kN), and MC (1.45 kN) groups (P > 0.05). For the PLZ, ILZ, and MC groups, all specimens fractured within the layering materials. In contrast, the fracture mode for the MONO group was complete fracture of the restorations. CONCLUSIONS: All restorations withstood the masticatory forces. Fracture loads were significantly higher for screw-retained implant-supported monolithic zirconia restorations than for screw-retained bilayered restorations. For the screw-retained bilayered zirconia-based restorations, the fracture resistance of ILZ restorations was comparable to that of PLZ restorations and MC restorations.

Linezolid-resistant Staphylococcus aureus isolated from 2006 through 2008 at six hospitals in Japan.

Limited use of linezolid for treating methicillin-resistant Staphylococcus aureus (MRSA) infection was approved in Japan in 2006. We report here the status of linezolid-resistant MRSAs in Japan. Eleven linezolid-resistant clinical isolates from 11 patients at six hospitals were collected from 2006 through 2008. The minimal inhibitory concentration (MIC) of linezolid in these strains varied from 8 to 64 µg/ml. All strains had at least one G2576T mutation in the chromosomal gene(s) encoding domain V of the 23S ribosomal RNA (rRNA). Chromosomal DNA encoding five copies of the domain V region was analyzed by polymerase chain reaction (PCR). Strains with the linezolid MICs of 64, 32, 16, and 8 µg/ml had the G2576T mutation(s) in four, three (or four), two, and one copy of the 23S rRNA genes, respectively. These results suggest that the level of linezolid resistance seems to be roughly correlated with the number of mutations in the genes encoding 23S rRNA. DNA samples from all 11 strains were subjected to pulsed-field gel electrophoresis and were classified into seven independent clones having >92% identity. Among the 11 patients, five had been treated with linezolid and the remainder, in two hospitals, had no history of prior linezolid use. The results suggested possible nosocomial infections by linezolid-resistant MRSA.

Long-term Bond Strength between Layering Indirect Composite Material and Zirconia Coated with Silicabased Ceramics.

PURPOSE: This study evaluated the long-term shear bond strength between an indirect composite material and a zirconia framework coated with silica-based ceramics, taking the effect of different primers into account. MATERIALS AND METHODS: A total of 165 airborne-particle abraded zirconia disks were subjected to one of three pretreatments: no pretreatment (ZR-AB), airborne-particle abrasion of zirconia coated with feldspathic porcelain (ZR-PO-AB), and 9.5% hydrofluoric acid etching of zirconia coated with feldspathic porcelain (ZR-PO-HF). An indirect composite material (Estenia C&B) was then bonded to the zirconia disks after they were treated with one of the following primers: Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB + Activator), Estenia Opaque Primer (EOP), Porcelain Liner M Liquid B (PLB), or no priming (CON, control group). Shear bond strength was tested after 100,000 thermocycles, and the data were analyzed using the Steel-Dwass U-test (α = 0.05). RESULTS: For ZR-PO-AB and ZR-PO-HF specimens, bond strength was highest in the CPB+Activator group (25.8 MPa and 22.4 MPa, respectively). Bond strengths were significantly lower for ZR-AB specimens in the CON and PLB groups and for ZR-PO-AB specimens in the CON, CPB, and EOP groups. CONCLUSION: Combined application of a hydrophobic phosphate monomer (MDP) and silane coupling agent enhanced the long-term bond strength of indirect composite material to a zirconia coated with silica-based ceramics.

Triaxial transarterial embolization for lower gastrointestinal bleeding: a retrospective case series.

OBJECTIVE: Superselective transcatheter arterial embolization (TAE) is important for lower gastrointestinal (GI) bleeding. A new 1.9-Fr. no-taper microcatheter has recently become available and can be inserted into a 2.7-Fr. microcatheter. We assessed the applicability of this new triple co-axial (triaxial) system to TAE for lower GI bleeding. MATERIAL AND METHODS: Five patients with lower GI bleeding underwent TAE with the triaxial system. The approach was via the femoral artery with a 4-Fr. sheath in all cases. The 4-Fr. catheter and triaxial system were inserted into the artery in which extravasation had occurred. Coil embolization was performed with 0.010-inch coils. We evaluated technical success rate, clinical success rate and complications. RESULTS: All five cases of bleeding occurred at the ascending colon, and were caused by diverticulosis in four cases, and an injury to the artery during polypectomy in one case. The 1.9-Fr. no-taper microcatheter could be inserted into the site of extravasation, the vasa recta, in all procedures and TAE was performed successfully. The disappearance of extravasation was confirmed in all cases following TAE. No patients exhibited any signs of recurrent bleeding or complication. CONCLUSION: The triaxial system appears to be effective and useful in superselective TAE for lower GI bleeding.