Comparison of fit accuracy of pressed lithium disilicate inlays fabricated from wax or resin patterns with conventional and CAD-CAM technologies.

STATEMENT OF PROBLEM: The use of resin patterns to produce partial coverage restorations is poorly documented. PURPOSE: The purpose of this in vitro study was to compare the marginal and internal fit accuracy of lithium disilicate glass-ceramic inlays obtained from wax or resin patterns and fabricated with digital and conventional techniques. MATERIAL AND METHODS: A dentoform mandibular first molar was prepared for a mesio-occlusal ceramic inlay. Six groups of 15 inlays were obtained by conventional impression and manual wax (group CICW) or resin patterns (group CICR); conventional impression, laboratory scanning of the stone die, CAD-CAM milled wax (group CIDW), or polymethylmethacrylate (PMMA) blocks (group CIDR); and scanning of the master preparation with an intraoral scanner, CAD-CAM milled wax (group DSDW), or PMMA blocks (DSDR). The same design was applied to produce the wax and PMMA patterns in the last 4 groups. The replica technique was used to measure marginal and internal fit under stereomicroscopy. Mixed-model ANOVA was applied to assess differences according to the techniques, materials, and discrepancy location (α=.05). RESULTS: The results demonstrated significant effects of the technique (P<.001), material (P=.009), and discrepancy location (P<.001) on fit measurements. Marginal discrepancy was only affected by the technique (P<.001), with the digital approaches yielding the smallest marginal discrepancy (23.5 ±3.6 µm), followed by the conventional digital techniques (31.1 ±5.6 µm) and finally by the conventional (42.8 ±7.2 µm) techniques. Internal fit was significantly influenced only by the material with lower discrepancy in wax (75.2 ±9.0 µm) than in resin patterns (84.7 ±15.1 µm). The internal discrepancy was significantly larger than the marginal discrepancy in all groups (P<.001). CONCLUSIONS: Inlays generated from conventional wax and resin patterns tend to show higher marginal discrepancies than conventional digital and full digital patterns. Wax and resin materials yield similar marginal fit accuracies irrespective of the impression/manufacturing technique. Better internal fit was shown in wax than in resin patterns, regardless of the technique.

Marginal and internal fit of pressed lithium disilicate inlays fabricated with milling, 3D printing, and conventional technologies.

STATEMENT OF PROBLEM: The subtractive and additive computer-aided design and computer-aided manufacturing (CAD-CAM) of lithium disilicate partial coverage restorations is poorly documented. PURPOSE: The purpose of this in vitro study was to compare the marginal and internal fit accuracy of lithium disilicate glass-ceramic inlays fabricated with conventional, milled, and 3-dimensional (3D) printed wax patterns. MATERIAL AND METHODS: A dentoform mandibular first molar was prepared for a mesio-occlusal ceramic inlay. Five groups of 15 inlays were obtained through conventional impression and manual wax pattern (group CICW); conventional impression, laboratory scanning of the stone die, CAD-CAM milled wax blanks (group CIDW) or 3D printed wax patterns (group CI3DW); and scanning of the master preparation with intraoral scanner and CAD-CAM milled (group DSDW) or 3D printed wax patterns (group DS3DW). The same design was used to produce the wax patterns in the last 4 groups. The replica technique was used to measure marginal and internal adaptation by using stereomicroscopy. Mixed-model ANOVA was used to assess differences according to the groups and discrepancy location (α=.05). RESULTS: Group DSDW showed the smallest marginal discrepancy (24.3 µm) compared with those of groups CICW (45.1 µm), CIDW (33.7 µm), CI3DW (39.8 µm), and DS3DW (39.7 µm) (P<.001). No statistically significant differences were detected among groups CICW, CIDW, CI3DW, and DS3DW relative to the marginal discrepancy. The internal discrepancy was significantly larger than the marginal discrepancy within all groups (P<.001). CONCLUSIONS: Lithium disilicate glass-ceramic inlays produced from digital scans and subtractive milling of wax patterns resulted in better marginal and internal fit accuracy than either conventional impression/fabrication or additive 3D manufacturing. Three-dimensional printed wax patterns yielded fit values similar to those of the conventionally waxed inlays.

Highly drug-resistant pathogens implicated in burn-associated bacteremia in an Iraqi burn care unit.

OBJECTIVE: In low- and middle-income countries, bloodstream infections are an important cause of mortality in patients with burns. Increasingly implicated in burn-associated infections are highly drug-resistant pathogens with limited treatment options. We describe the epidemiology of bloodstream infections in patients with burns in a humanitarian surgery project in Iraq. METHODS: We performed a retrospective, descriptive study of blood culture isolates identified between July 2008 and September 2009 among patients with burns in a single hospital in Iraq who developed sepsis. RESULTS: In 1169 inpatients admitted to the burn unit during the study period, 212 (18%) had suspected sepsis, and 65 (6%) had confirmed bacteremia. Sepsis was considered the primary cause of death in 198 patients (65%; 95% CI 65-70) of the 304 patients that died. The most commonly isolated organisms were Pseudomonas aeruginosa (22 isolates [34%]), Staphylococcus aureus (17 [26%]), Klebsiella pneumoniae (8 [12%]), Staphylococcus epidermidis (7 [11%]), Acinetobacter baumannii (6 [9%]), and Enterobacter cloacae (5 [8%]). A high proportion of Enterobacteriaceae strains produced extended-spectrum beta-lactamase and S. aureus isolates were uniformly methicillin-resistant. For gram-negative bacteria, the most reliably active antibiotics were imipenen and amikacin. CONCLUSIONS: Burn patients with sepsis in Iraq were commonly found to have bloodstream pathogens resistant to most antibiotics available locally. Effective empirical therapy of burn sepsis in this region of Iraq would consist of vancomycin or teicoplanin and a carbapenem-class antibiotic with antipseudomonal activity.

The human semicircular canals orientation is more similar to the bonobos than to the chimpanzees.

For some traits, the human genome is more closely related to either the bonobo or the chimpanzee genome than they are to each other. Therefore, it becomes crucial to understand whether and how morphostructural differences between humans, chimpanzees and bonobos reflect the well known phylogeny. Here we comparatively investigated intra and extra labyrinthine semicircular canals orientation using 260 computed tomography scans of extant humans (Homo sapiens), bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Humans and bonobos proved more similarities between themselves than with chimpanzees. This finding did not fit with the well established chimpanzee - bonobo monophyly. One hypothesis was convergent evolution in which bonobos and humans produce independently similar phenotypes possibly in response to similar selective pressures that may be associated with postural adaptations. Another possibility was convergence following a "random walk" (Brownian motion) evolutionary model. A more parsimonious explanation was that the bonobo-human labyrinthine shared morphology more closely retained the ancestral condition with chimpanzees being subsequently derived. Finally, these results might be a consequence of genetic diversity and incomplete lineage sorting. The remarkable symmetry of the Semicircular Canals was the second major finding of this article with possible applications in taphonomy. It has the potential to investigate altered fossils, inferring the probability of post-mortem deformation which can lead to difficulties in understanding taxonomic variation, phylogenetic relationships, and functional morphology.

CLN5 and CLN8 protein association with ceramide synthase: biochemical and proteomic approaches.

Four patients with juvenile neuronal ceroid lipofuscinoses, a childhood neurodegenerative disorder that was previously described as CLN9 variant, are reclassified as CLN5 disease. CLN5-deficient (CLN5(-/-) ) fibroblasts demonstrate adhesion defects, increased growth, apoptosis, and decreased levels of ceramide, sphingomyelin, and glycosphingolipids. The CLN8 protein (CLN8p) corrects growth and apoptosis in CLN5(-/-) cells. Related proteins containing a Lag1 motif (CerS1/2/4/5/6) partially corrected these deficits, with CerS1, which is primarily expressed in brain, providing the best complementation, suggesting CLN5p activates CerS1 and may co-immunoprecipitate with it. CLN8p complements CLN5-deficient cells, consolidating the interrelationship of CLN5p/CLN8p, whose potential roles are explored as activators of (dihydro)ceramide synthases. Homozygosity mapping using microarray technology led to identification of CLN5 as the culprit gene in previously classified CLN9-defective cases. Similar to CLN5(-/-) cells, ceramide synthase activity, C16/C18:0/C24:0/C24:1 ceramide species, measured by MS is decreased in CLN8(-/-) cells. Comparison of normal versus CLN5(-/-) cell CerS1-bound proteins by immunoprecipitation, differential gel electrophoresis, and MS revealed absence of γ-actin in CLN5(-/-) cells. The γ-actin gene sequence is normal in CLN5(-/-) derived DNA. The γ-actin-bound proteins, vimentin and histones H2Afz/H3F3A/Hist1H4, were absent from the γ-actin protein complex in CLN5(-/-) cells. The function of CLN5p may require vimentin and the histone proteins to bind γ-actin. Defective binding could explain the CLN5(-/-) cellular phenotype. We explore the role of the CLN5/CLN8 proteins in ceramide species specific sphingolipid de novo synthesis, and suggest that CLN5/CLN8 proteins are more closely related than previously believed.