Search

This animal study was performed to ascertain whether the regeneration of membrane-protected bone defects can be accelerated by the controlled application of basic fibroblast growth factor (FGF-2) using a new drug delivery system. Standardized alveolar bone defects were made surgically in 9 beagle dogs, and FGF-2 was administered using specially made collagen minipellets. A minipellet containing either 0.15 μg FGF-2 (FGF) or 0 μg FGF-2 (placebo) was placed in the defect or no minipellet was used (control), and bone regeneration was evaluated radiologically, histologically, and histometrically 8 weeks after the operation. Radiographs showed a surprisingly large radiopaque region in FGF sites compared with placebo or control sites. Histologically, mature bone filled the majority of the inner space of the membrane-protected defect in FGF sites. New bone formation was also seen in the control and the placebo sites, however, it filled less than half the area of the defect. Histometrically, the area of regenerated bone in FGF sites was significantly higher than in the other sites (P<0.01). These results demonstrate that the controlled application of FGF-2 accelerates bone regeneration in membrane-protected bone defects in the canine model. [ABSTRACT FROM AUTHOR]

The objective of this study is to evaluate the impact of the thickness and translucency of various computer-aided design/computer-aided manufacturing (CAD/CAM) materials on the polymerization of dual-cure resin cement in endocrown restorations. Three commercially available CAD/CAM materials—lithium disilicate glass (e.max CAD), resin composite (CERASMART), and a polymer-infiltrated ceramic network (ENAMIC)—were cut into plates with five different thicknesses (1.5, 3.5, 5.5, 7.5, and 9.5 mm) in both high-translucency (HT) and low-translucency (LT) grades. Panavia V5, a commercial dual-cure resin cement, was polymerized through each plate by light irradiation. Post-polymerization treatment was performed by aging at 37 °C for 24 h under light-shielding conditions. The degree of conversion and Vickers hardness measurements were used to characterize the polymerization of the cement. The findings revealed a significant decrease in both the degree of conversion and Vickers hardness with increasing thickness across all CAD/CAM materials. Notably, while the differences in the degree of conversion and Vickers hardness between the HT and LT grades of each material were significant immediately after photoirradiation, these differences became smaller after post-polymerization treatment. Significant differences were observed between samples with a 1.5 mm thickness (conventional crowns) and those with a 5.5 mm or greater thickness (endocrowns), even after post-polymerization treatment. These results suggest that dual-cure resin cement in endocrown restorations undergoes insufficient polymerization. [ABSTRACT FROM AUTHOR]

Poly-ether-ether-ketone (PEEK) is commonly employed in dental prostheses owing to its excellent mechanical properties; however, it is limited by its low bond strength with dental resin cement. This study aimed to clarify the type of resin cement most suitable for bonding to PEEK: methyl methacrylate (MMA)-based resin cement or composite-based resin cement. For this purpose, two MMA-based resin cements (Super-Bond EX and MULTIBOND II) and five composite-based resin cements (Block HC Cem, RelyX Universal Resin Cement, G-CEM LinkForce, Panavia V5, and Multilink Automix) were used in combination with appropriate adhesive primers. A PEEK block (SHOFU PEEK) was initially cut, polished, and sandblasted with alumina. The sandblasted PEEK was then bonded to resin cement with adhesive primer according to the manufacturer's instructions. The resulting specimens were immersed in water at 37 °C for 24 h, followed by thermocycling. Subsequently, the tensile bond strengths (TBSs) of the specimens were measured; the TBSs of the composite-based resin cements after thermocycling were found to be zero (G-CEM LinkForce, Panavia V5, and Multilink Automix), 0.03 ± 0.04 (RelyX Universal Resin Cement), or 1.6 ± 2.7 (Block HC Cem), whereas those of Super-Bond and MULTIBOND were 11.9 ± 2.6 and 4.8 ± 2.3 MPa, respectively. The results demonstrated that MMA-based resin cements exhibited stronger bonding to PEEK than composite-based resin cements. [ABSTRACT FROM AUTHOR]

Objectives: Previous studies have indicated that xerostomia is a critical factor affecting periodontitis; nonetheless, it is controversial whether xerostomia impairs peri‐implant tissue. The objective of this experimental study was to evaluate the effect of xerostomia on the peri‐implant hard and soft tissues in the rat model. Materials and methods: Implants were placed in bilateral maxillae of male Wistar rats. The animals underwent submandibular and sublingual gland resection on both sides (DRY group) or sham operation (CTR group). Silk ligatures were placed around one side of abutments, which were randomly selected in each animal. The effects of xerostomia were assessed using micro‐CT, histological analysis, real‐time PCR, and 16S rRNA‐based metagenomic analysis. Results: Ligation with silk thread caused bone resorption around implants. Although xerostomia itself did not induce bone resorption, it significantly enhanced silk ligature‐mediated bone resorption around implants. Histological analysis and real‐time PCR indicated that xerostomia induced inflammation and osteoclastogenesis around implants with silk ligatures. Furthermore, it altered the microbiota of the plaque on the silk thread around implants. Conclusion: Xerostomia accelerates mucosal inflammation and osteoclastogenesis, which aggravates bone resorption around implants. [ABSTRACT FROM AUTHOR]

Reconstruction of a critical-sized osseous defect is challenging in maxillofacial surgery. Despite novel treatments and advances in supportive therapies, severe complications including infection, nonunion, and malunion can still occur. Here, we aimed to assess the use of a beta-tricalcium phosphate (β-TCP) scaffold loaded with high mobility group box-1 protein (HMGB-1) as a novel critical-sized bone defect treatment in rabbits. The study was performed on 15 specific pathogen-free New Zealand rabbits divided into three groups: Group A had an osseous defect filled with a β-TCP scaffold loaded with phosphate-buffered saline (PBS) (100 µL/scaffold), the defect in group B was filled with recombinant human bone morphogenetic protein 2 (rhBMP-2) (10 µg/100 µL), and the defect in group C was loaded with HMGB-1 (10 µg/100 µL). Micro-computed tomography (CT) examination demonstrated that group C (HMGB-1) showed the highest new bone volume ratio, with a mean value of 66.5%, followed by the group B (rhBMP-2) (31.0%), and group A (Control) (7.1%). Histological examination of the HMGB-1 treated group showed a vast area covered by lamellar and woven bone surrounding the β-TCP granule remnants. These results suggest that HMGB-1 could be an effective alternative molecule for bone regeneration in critical-sized mandibular bone defects. [ABSTRACT FROM AUTHOR]

Background: Although many studies have been conducted on the relationship between masticatory performance and nutrient ingestion in the elderly, few large‐scale studies have been carried out using relatively young individuals. Objectives: The objective of this study was to clarify the association between the masticatory performance evaluated by the gummy‐jelly test, not by visual examination, and nutrient ingestion state based on the brief self‐administered diet history questionnaire (BDHQ). Methods: This was a cross‐sectional survey of 540 male workers. Somatometry, blood pressure measurement, blood test and medical interview were performed as a periodic health check‐up. In the dental check‐up, an oral examination, gummy‐jelly test (glucosensor) and survey of ingested food and nutrients using BDHQ were performed. The participants were classified into two groups with low and normal values of masticatory performance. Participants with a score on the gummy‐jelly test below 150 mg/dL or 150 mg/dL or higher were included in the low and normal groups, respectively. Results: Two hundred and forty‐eight participants (45.8%) had low masticatory performance, and 292 (53.2%) had normal masticatory performance. The intakes of some minerals and vitamins, such as calcium, vitamin D, vitamin B2, small fish with bones and non‐oily fish, were significantly lower in the low masticatory group than in the normal group. In contrast, the intake of sugar for coffee and tea and that of chicken were significantly higher in the low masticatory group than in the normal group. Conclusion: This study suggested that low masticatory performance can affect nutrient intake, which may cause non‐communicable diseases. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the longitudinal association of the combination of poor appetite (PA) and low masticatory function (LMF) with sarcopenia in community‐dwelling older adults. Methods: In total, 173 community‐dwelling Japanese adults aged ≥ 75 years participated in the 3‐year cohort study. Appetite assessment using the Simplified Nutritional Appetite Questionnaire (SNAQ) and masticatory function assessment using spectrophotometric measurement of differences in gum colour before and after masticating colour‐changeable chewing gum (ΔE*ab) were performed at baseline. SNAQ score of ≤ 14 was defined as PA. The lowest tertile of ΔE*ab was defined as LMF. Follow‐up examinations were administered annually over a 3‐year period to determine sarcopenia incidence, which was defined by the criteria proposed by the Asian Working Group for Sarcopenia. Adjusted hazard ratios (HRs) of sarcopenia incidence according to the presence of PA and LMF were calculated using Cox proportional hazards regression models. Results: At baseline, 81 participants (46.8%) had neither PA nor LMF, 34 (19.7%) had PA alone, 35 (20.2%) had LMF alone, and 23 (13.3%) had both PA and LMF. On follow‐up, 31 participants (17.9%) developed sarcopenia. After adjusting for covariates, the adjusted HR for sarcopenia in participants with both PA and LMF was 4.4 (95% confidence interval = 1.6‐12.2) compared with those without PA or LMF. PA or LMF alone was not significantly associated with sarcopenia development. Conclusions: Coexisting PA and LMF increase the risk of sarcopenia development among community‐dwelling Japanese adults aged ≥ 75 years. [ABSTRACT FROM AUTHOR]

Podosome formation in osteoclasts is an important initial step in osteoclastic bone resorption. Mice lacking c‐Src (c‐Src−/−) exhibited osteopetrosis due to a lack of podosome formation in osteoclasts. We previously identified p130Cas (Crk‐associated substrate [Cas]) as one of c‐Src downstream molecule and osteoclast‐specific p130Cas‐deficient (p130CasΔOCL−/−) mice also exhibited a similar phenotype to c‐Src−/− mice, indicating that the c‐Src/p130Cas plays an important role for bone resorption by osteoclasts. In this study, we performed a cDNA microarray and compared the gene profiles of osteoclasts from c‐Src−/− or p130CasΔOCL−/− mice with wild‐type (WT) osteoclasts to identify downstream molecules of c‐Src/p130Cas involved in bone resorption. Among several genes that were commonly downregulated in both c‐Src−/− and p130CasΔOCL−/− osteoclasts, we identified kinesin family protein 1c (Kif1c), which regulates the cytoskeletal organization. Reduced Kif1c expression was observed in both c‐Src−/− and p130CasΔOCL−/− osteoclasts compared with WT osteoclasts. Kif1c exhibited a broad tissue distribution, including osteoclasts. Knockdown of Kif1c expression using shRNAs in WT osteoclasts suppressed actin ring formation. Kif1c overexpression restored bone resorption subsequent to actin ring formation in p130CasΔOCL−/− osteoclasts but not c‐Src−/− osteoclasts, suggesting that Kif1c regulates osteoclastic bone resorption in the downstream of p130Cas (191 words). Significance of the study: We previously showed that the c‐Src/p130Cas (Cas) plays an important role for bone resorption by osteoclasts. In this study, we identified kinesin family protein 1c (Kif1c), which regulates the cytoskeletal organization, as a downstream molecule of c‐Src/p130Cas axis, using cDNA microarray. Knockdown of Kif1c expression using shRNAs in wild‐type osteoclasts suppressed actin ring formation. Kif1c overexpression restored bone resorption subsequent to actin ring formation in osteoclast‐specific p130Cas‐deficient (p130CasΔOCL−/−) osteoclasts but not c‐Src−/− osteoclasts, suggesting that Kif1c regulates osteoclastic bone resorption in the downstream of p130Cas. [ABSTRACT FROM AUTHOR]

Background Hypofunction of different organs in the body is associated with diabetes, including in the oral cavity. Diabetes is often associated with xerostomia, but the underlying mechanism is not well characterized. Thus, the mechanisms underlying diabetes-induced xerostomia were investigated in this study in KK-A y mice as an experimental model of type 2 diabetes. Methods The mechanisms involved in diabetes-induced xerostomia were investigated using the ex vivo glandular perfusion technique, histological analysis, and immunohistochemical and intracellular signaling analyses. Results Ex vivo submandibular gland secretions from KK-Ay mice decreased by 30% following stimulation with 0.3 μmol/L carbachol ( CCh), a cholinergic agonist. Acinar cell weight was comparable between KK-Ay and control mice, whereas duct cell weight was significantly greater in KK-Ay mice. Concentrations of Na+ and Cl− in the secreted saliva decreased significantly in KK-Ay mice, supporting the finding of increased ductal tissue in KK-Ay mice. Immunohistochemistry revealed no significant differences between KK-Ay and control mice in terms of the expression of Cl− and water channels, Na+-K+-2Cl− cotransporters, and membrane proteins critical for fluid secretion. Cellular signaling analysis revealed that the increase in [Ca2+]i in response to 0.3 μmol/L CCh was reduced by 30% in KK-Ay mice, although there was no significant difference in the thapsigargin (1.0 μmol/L)-induced increase in store-depleted calcium between KK-Ay and control mice. Conclusions These results demonstrate that submandibular fluid secretion is diminished in KK-Ay mice because of a diminished increase in [Ca2+]i. Duct cell weight increased in KK-Ay mice, possibly leading to increased ion reabsorption and thus decreased Na+ and Cl− concentrations in the secreted saliva. [ABSTRACT FROM AUTHOR]

Objective The aim of this prospective clinical study was to evaluate longitudinal changes in oral health-related quality of life ( OHRQo L) attributable to fixed dental prostheses during All-on-4® treatment in one or both jaws. Materials and methods Ten patients underwent placement of four or six endosteal dental implants on the basis of the All-on-4® treatment concept in the edentulous maxilla or both jaws and immediate loading with acrylic interim prostheses. The prostheses were replaced after 3-6 months, and definitive prostheses with titanium framework and reinforced resin facing were fixed after another 5 months or more. The subjects completed the shortened Japanese version of the Oral Health Impact Profile ( OHIP-J14) before the surgery (T0), 1 week after the initial (T1) and secondary (T2) interim prostheses were placed, and 3 months after definitive prosthesis placement (T3). Complete data of nine subjects were analyzed with the Wilcoxon signed-rank test. Results The total OHIP-J14 score significantly reduced only at T3 ( P < 0.05). 'Functional limitation,' 'physical pain,' 'physical disability,' and 'psychological disability' scores significantly decreased at T3, and 'psychological discomfort' scores also significantly dropped at T2. 'Social disability' and 'handicap' scores remained unchanged throughout. Conclusion Fixed definitive prostheses with metal framework are more effective than fixed all-acrylic prostheses in improving OHRQoL during All-on-4® treatment. [ABSTRACT FROM AUTHOR]

A close relationship between the bone and systemic glucose metabolism has recently been the center of attention, since the uncarboxylated form of osteocalcin (GluOC), a bone-derived protein, but not the γ-carboxylated form, is involved in glucose metabolism. However, the analysis of GluOC effect using isolated organs and related cell lines are required to understand its roles in a whole systemic metabolic status. In the present study, we examined the effect of GluOC on cell lines derived from skeletal muscle to explore the mechanisms by which GluOC regulates glucose uptake. In the differentiated C2C12 myotubes, GluOC dose-dependently induced the phosphorylation of ERK without affecting intracellular cAMP and Ca 2+ levels. This effect was inhibited by U0126, an inhibitor of ERK kinase (MEK). Additionally, U73122, an inhibitor of phospholipase C tended to inhibit it as well. Furthermore, cell treatment with GluOC for a long period promoted insulin-induced Akt phosphorylation and glucose uptake in the myotubes, which was abolished by ERK signaling inhibition. These results indicate that GluOC does not triggered Akt phosphorylation and glucose uptake by itself but promotes insulin-induced glucose uptake in myotubes, probably by up-regulating Akt signaling through ERK activation. [ABSTRACT FROM AUTHOR]

Objective The aims of this clinical study were to determine differences in plaque accumulation and to compare the effects of reinforced composite resin and titanium on peri-implant soft-tissue and residual-ridge inflammation. Material and methods A total of 19 subjects were enrolled in this clinical trial; 10 jaws had implant-supported fixed prostheses with composite resin mucosal surfaces, 11 jaws had titanium prostheses fabricated by computer-aided design/computer-aided manufacture ( CAD/ CAM), and 6 jaws had acrylic resin prostheses. Plaque area indexes ( PAIs) were calculated on the mucosal surfaces of prostheses, and blood flow in the mucosa was captured with two-dimensional laser speckle imaging to evaluate residual-ridge inflammation. Subjects were educated about oral hygiene and reevaluated after 3 months. Results The PAI was significantly lower on titanium mucosal surfaces than on reinforced composite resin surfaces at the initial and second measurements (initial, P = 0.0052; second, P = 0.0044). Self-curing acrylic resin surfaces did not show any significant difference when compared with reinforced resin or titanium. Blood flow was significantly lower in mucosa contacting titanium surfaces than in mucosa contacting reinforced composite resin surfaces at the initial measurement ( P = 0.0330). Although subjects were instructed about plaque control after the initial measurement, PAIs indicated that the difference between the two materials could not be overcome. Conclusion In terms of oral hygiene and mucosal inflammation, titanium was superior to reinforced composite resin in implant-supported fixed prostheses for edentulous subjects, and the short-term use of acrylic resin was superior to the use of reinforced composite resin. [ABSTRACT FROM AUTHOR]

Poly(methyl methacrylate) (PMMA) is widely used in dental applications. However, PMMA specialized for stereolithography (SLA) additive manufacturing (3D-printing) has not been developed yet. This study aims to develop a novel PMMA-based resin for SLA 3D-printing by mixing methyl methacrylate (MMA), ethylene glycol dimethacrylate (EGDMA), and PMMA powder in various mixing ratios. The printability and the viscosity of the PMMA-based resins were examined to determine their suitability for 3D-printing. The mechanical properties (flexural strength and Vickers hardness), shear bond strength, degree of conversion, physicochemical properties (water sorption and solubility), and cytotoxicity for L929 cells of the resulting resins were compared with those of three commercial resins: one self-cured resin and two 3D-print resins. EGDMA and PMMA were found to be essential components for SLA 3D-printing. The viscosity increased with PMMA content, while the mechanical properties improved as EGDMA content increased. The shear bond strength tended to decrease as EGDMA increased. Based on these characteristics, the optimal composition was determined to be 30% PMMA, 56% EGDMA, 14% MMA with flexural strength (84.6 ± 7.1 MPa), Vickers hardness (21.6 ± 1.9), and shear bond strength (10.5 ± 1.8 MPa) which were comparable to or higher than those of commercial resins. The resin's degree of conversion (71.5 ± 0.7%), water sorption (19.7 ± 0.6 μg/mm3), solubility (below detection limit), and cell viability (80.7 ± 6.2% at day 10) were all acceptable for use in an oral environment. The printable PMMA-based resin is a potential candidate material for dental applications. [ABSTRACT FROM AUTHOR]

Abstract: Cigarette smoking and nicotine enhance parotid saliva secretion, however, the underlying mechanism is unclear. To address the mechanism of nicotine-induced salivation and to explore the possibility that nicotinic receptor agonists act as sialogogues, we investigated the effects of nicotinic receptor agonists on salivary secretion in vivo and on intracellular Ca2+ concentration in digested parotid acini in vitro in rats. In urethane-anesthetized rats, intravenous administration of nicotinic receptor agonists, nicotine and cytisine, at 3μmol/kg increased whole saliva output accompanied by a pressor response with nicotine, but not with cytisine. Using Ca2+-imaging system on digested parotid acini in which autonomic nerve terminals were kept intact, nicotine and cytisine dose-dependently increased intracellular Ca2+ concentration at μM level. This was not observed in single acinar cells containing no nerve terminal. The nicotine-induced Ca2+ response was largely blocked by a muscarinic receptor antagonist and partly blocked by an adrenergic receptor antagonist. Furthermore, the same nicotine-induced Ca2+ response was blocked by mecamylamine, a relatively selective nicotinic antagonist for α3β4 subtype receptor, but not by other selective antagonists, dihydro-β-erythroidine for α4-containing receptor and methyllycaconitine for α7 nicotinic receptors. These results suggest that nicotinic agonists-induced salivation is due to a release of acetylcholine and noradrenaline from autonomic nerve terminals through activation of α3β4 nicotinic receptor subtype. In addition, considering the blood pressure response and development of addiction with nicotine, cytisine may be a better therapeutic candidate to serve as a sialogogue for xerostomia patients. [Copyright &y& Elsevier]

Abstract: Proteasome inhibitors enhance bone formation and osteoblastic differentiation in vivo and in vitro. In the present study, we examined whether the molecular mechanisms of lactacystin, one of many proteasome inhibitors, stimulated the osteoblastic differentiation of C2C12 cells that is induced by bone morphogenetic proteins (BMPs). Pretreatment with lactacystin enhanced the alkaline phosphatase (ALP) activity induced by BMP2, BMP4 or BMP7, but lactacystin did not induce ALP in the absence of BMPs. In addition, lactacystin-stimulated BMP2 induced mRNA expression of ALP, type I collagen, osteonectin, osteocalcin, Id1, Osterix, and Runx2. Lactacystin maintained BMP2-induced phosphorylation of Smad1/5/8 and increased the length of time that these Smads were bound to target DNA. Moreover, lactacystin prevented BMP receptor-induced Smad degradation. This enhancement of BMP2-induced ALP activity and Smad phosphorylation by lactacystin was also observed in primary osteoblasts. These findings suggest that pretreatment with lactacystin accelerates BMP-induced osteoblastic differentiation by increasing the levels of phosphorylated Smads, which are maintained because BMP receptor-induced degradation is inhibited. We propose that optimized stimulation by proteasome inhibitors in a clinical setting may facilitate autogenous or BMP-induced bone formation in areas of defective bone. [Copyright &y& Elsevier]

Abstract: Gingival epithelial-like cells (GE-1) were cultured and used to examine the cellular responses of gingival tissues to varying concentrations of titanium (Ti) ions. Titanium ions at concentrations of more than 13ppm significantly decreased the viability of GE-1 cells and increased LDH release from the cells into the supernatant, but had no significant effect on their caspase 3 activity. These data suggest that a high concentration of Ti ions induced necrosis of the GE-1 cells. Titanium ions at a concentration of 5ppm significantly increased the level of CCL2 mRNA expression in GE-1 cells exposed to lipopolysaccharide derived from Porphyromonas gingivalis in a synergistic manner. Moreover, the mRNA expression levels of TLR-4 and ICAM-1 in GE-1 cells loaded with Ti ions at 9ppm were significantly enhanced as compared with those in GE-1 cells without Ti stimulation. We suggest that Ti ions are in part responsible for monocyte infiltration in the oral cavity by elevating the sensitivity of gingival epithelial cells to microorganisms. Taken together, these data indicate that Ti ions may be involved in cytotoxicity and inflammation at the interfaces of dental implants and gingival tissue. [ABSTRACT FROM AUTHOR]

Abstract: There are few data available regarding the differences in intracellular Ca2+ responses of parotid acinar and ductal cells. This study investigated the Ca2+ mobilization that was induced by the chemical stimulation of acinar and ductal cells from rat parotid glands. In fura-2 loaded parotid cells, carbachol increased the intracellular Ca2+ concentration ([Ca2+]i) to a greater extent in the acinar cells than in the ductal cells, but noradrenaline increased the [Ca2+]i in the ductal cells more than in the acinar cells. Although there was no difference in the α1-adrenergic receptor agonist phenylephrine-induced Ca2+ mobilization between acini and ducts, the β-adrenergic receptor agonist isoproterenol increased the [Ca2+]i in only the ductal cells. Additionally, the effects of non-adrenergic, non-cholinergic neurotransmitters were investigated. Substance P and ATP increased the [Ca2+]i in parotid acini and/or ducts. A substance P-induced Ca2+ response was observed in only acini, while the ATP-induced Ca2+ response was significantly higher in ducts than in acini. These results suggest that parotid acini have a greater sensitivity to cholinergic and substance P stimulation and a lesser sensitivity to β-adrenergic and ATP stimulation than the ductal cells. In light of these results, substance P and isoproterenol will be useful for identifying parotid acini and ducts, respectively. [Copyright &y& Elsevier]

Polymer infiltrated ceramic network (PICN) composites are an increasingly popular dental restorative material that offer mechanical biocompatibility with human enamel. This study aimed to develop a novel PICN composite as a computer-aided design and computer-aided manufacturing (CAD/CAM) block for dental applications. Several PICN composites were prepared under varying conditions via the sintering of a green body prepared from a silica-containing precursor solution, followed by resin infiltration. The flexural strength of the PICN composite block (107.8–153.7 MPa) was similar to a commercial resin-based composite, while the Vickers hardness (204.8–299.2) and flexural modulus (13.0–22.2 GPa) were similar to human enamel and dentin, respectively. The shear bond strength and surface free energy of the composite were higher than those of the commercial resin composites. Scanning electron microscopy and energy dispersive X-ray spectroscopic analysis revealed that the microstructure of the composite consisted of a nanosized silica skeleton and infiltrated resin. The PICN nanocomposite block was successfully used to fabricate a dental crown and core via the CAD/CAM milling process. [ABSTRACT FROM AUTHOR]