Publications by authors named "Dorin Ruse"
Purpose: To compare the marginal and internal fit of monolithic zirconia (MZ) 3-unit fixed dental prostheses (FDPs) fabricated using two CAD/CAM workflows: full-chairside (FCH) and lab (LAB).
Materials And Methods: The right maxillary first premolar and first molar were prepared for MZ 3-unit FDPs on a typodont. CEREC Primescan digitized the typodont model 15 Omes.
To develop a model to test cyclic fatigue resistance of TruNatomy instruments undergoing rotational and axial movement at body temperature. A total of 288 Prime and Medium instruments were subjected to cyclic fatigue testing in simulated canals (at 37°C) using a model with either rotational movement only or rotational and axial movement simultaneously. Two different sized canals and three different types of curvatures were tested for each instrument (30/0.
View Article and Find Full Text PDFObjectives: The aim of this study was to determine and compare fracture toughness (K) and work of fracture (WOF) of a conventional (C) denture base, using the notchless triangular prism (NTP) specimen K test, with CAD/CAM (milled, M) and 3D-printed (P) materials at 7 d and 90 d.
Methods: Lucitone 199 (C), Lucitone 199 CAD (M) and Lucitone Digital Print (P) (Dentsply, USA) were used to fabricate NTP specimens. Samples were stored in 37 °C water for 7 d (20/group) and 90 d (20/group) and conditioned in 23 °C water for 1 h prior to testing.
Objectives: The present study examined the defect characteristics of clinically-used, discarded nickel titanium rotary retreatment instruments and analysed the impact of clinical use on their metallurgical properties.
Methods: 92 XP-endo Shaper (XPS; FKG Dentaire) and 20 XP-endo Finisher (XPFR; FKG Dentaire) instruments with structural deformation or separation were collected after retreatment from four endodontic clinics over a 20-month period. The types of defects and their relative locations were recorded.
Purpose: To determine and compare the fracture toughness, flexural strength and flexural modulus of four new, commercially available CAD/CAM resin composite blocks and one new CAD/CAM lithium disilicate glass-ceramic block, tested under dry and aged conditions.
Materials And Methods: Three dispersed-fillers resin composite blocks, CERASMART, KZR-CAD-HR2, and CAMouflage NOW, one polymer-infiltrated ceramic network resin composite block, Enamic, along with Obsidian, a lithium disilicate glass-ceramic block, were characterized. Fracture toughness was determined through the notchless triangular prism specimen test, while flexural strength and flexural modulus were determined by three-point bend testing.
Objective: To compare shear bond strength (SBS) and interfacial fracture toughness (IK) results when assessing the effect of surface roughness and thermocycling on the adherence of a resin composite luting agent (RCLA) to a CAD/CAM resin composite block (RCB).
Methods: Tetric CAD HT along with the recommended bonding system, Adhese Universal and Variolink Esthetic LC, were used. Surface roughness was achieved with 600/320/60 grit SiC papers.
Purpose: To apply fracture mechanics methodology to determine the interfacial fracture toughness of the interfaces present in "CAD-on" crowns consisting of CAD/CAM milled lithium disilicate veneers glass-fused to CAD/CAM milled yttrium oxide stabilized tetragonal zirconia polycrystal framework.
Materials And Methods: The notchless triangular prism specimen fracture toughness test was used to determine interfacial fracture toughness. Four groups, each consisting of (6 × 6 × 6 × 12) mm prisms (n = 22), were produced.
Purpose: Resin composite blocks (RCB) are advocated as alternative to ceramic blocks (CB). Prior to use, adherence to these materials should characterized. This study aimed to test the null hypothesis (H ) that material and surface treatment combinations do not influence interfacial fracture toughness (K ) of a self-cured adhesive resin cement [RelyX Ultimate (RXU)] to RCB or CB, under nonaged and aged conditions.
View Article and Find Full Text PDFPurpose: To compare the marginal fit of lithium disilicate (LD) crowns fabricated with digital impression and manufacturing (DD), digital impression and traditional pressed manufacturing (DP), and traditional impression and manufacturing (TP).
Materials And Methods: Tooth #15 was prepared for all-ceramic crowns on an ivorine typodont. There were 45 LD crowns fabricated using three techniques: DD, DP, and TP.
Statement Of Problem: IPS e.max CAD and IPS e.max Press (Ivoclar Vivadent AG) are lithium disilicate glass ceramics marketed as interchangeable materials indicated for the same clinical uses.
View Article and Find Full Text PDFVertebral compression fractures can be successfully restored by injectable bone cements. Here the as-yet unexplored in vitro cytotoxicity, in vivo biodegradation, and osteoconductivity of a new calcium phosphate silicate cements (CPSC) are studied, where monocalcium phosphate (MCP; 5, 10, and 15 wt%) is added to calcium silicate cement (CSC). Setting rate and compressive strength of CPSC decrease with the addition of MCP.
View Article and Find Full Text PDFIntroduction: The aims of this study were to determine the flexibility of ProFile Vortex (VX) and Vortex Blue (VB) files (Dentsply Tulsa Dental Specialties, Tulsa, OK) and then to evaluate and compare their fatigue resistance in artificial single curvature and 2 different artificial double curvature canals.
Methods: Flexibility of the files (size 25/.04) in bending was assessed according to ISO 3630-1.
Purpose: The aim of this study was to compare the internal fit of lithium disilicate crowns fabricated using digital technology with those fabricated by conventional means.
Materials And Methods: Forty-five lithium disilicate crowns were fabricated: 15 using digital impression and computer-aided design/computer-aided machining technique (group 1), 15 from the same digital impressions, but using a conventional die and laboratory fabrication process (group 2), and 15 using a conventional poly (vinyl siloxane) (PVS) impression and laboratory fabrication process (group 3). Tooth #15 was prepared for all-ceramic restoration on an ivorine typodont, which was digitized and a replica milled in zirconia to serve as master model.
Objectives: The aim of this study, part of our research to improve properties of resin composite blocks suitable for CAD/CAM and to better understand underlying mechanisms associated with high-temperature/high-pressure (HT/HP) polymerization, was to determine an optimum polymerization pressure of urethane dimethacrylate (UDMA) in the presence of an initiator (0.5% benzoyl peroxide) by determining the degree of conversion (DC) and viscoelastic properties of polymers obtained at 90°C under varying HP.
Methods: DC and viscoelastic properties of 16 UDMA polymers, two controls (thermo-cured and thermo-cured followed by post-cure relaxation) and 14 experimental groups (HP polymers, in the range of 50-350 MPa, in 50 MPa increments, without and with post-cure relaxation) were determined via near infrared spectroscopic analysis and dynamic mechanical analysis, respectively.
Objectives: The aim of this study was to compare the viscoelastic properties of high pressure (HP) polymerized urethane dimethacrylate (UDMA) with those of control, ambient pressure thermo-polymerized and photo-polymerized, UDMA and to assess the effect of varying polymerization parameters (protocol, temperature, and initiator) on the viscoelastic properties of HP polymerized UDMA.
Methods: The viscoelastic properties of the two control polymers, polymerized under atmospheric pressure, and four experimental polymers, polymerized under HP, were determined via dynamic mechanical analysis (DMA), in three point bending configuration. Atomic force microscopy (AFM) was used to characterize fractured polymer surface morphologies.
A comparison of the marginal fit of crowns fabricated with digital and conventional methods.
J Prosthet Dent
September 2014
Statement Of Problem: Little evidence is available with regard to the marginal fit of crowns fabricated with digital impressions and computer-aided design/computer-aided manufacturing technology in comparison with crowns fabricated from conventional techniques.
Purpose: The purpose of this study was to determine and compare the marginal fit of crowns fabricated with digital and conventional methods.
Material And Methods: The maxillary right second premolar was prepared for a ceramic crown in a typodont.
Objective: This study was conducted to determine selected mechanical/physical properties of and monomer release from high-temperature high-pressure (HT/HP) polymerized urethane dimethacrylate (UDMA).
Methods: Flexural strength (σf), hardness, fracture toughness (KIC), and density (ρ) were determined for five UDMA resin blocks produced via different polymerization protocols. High performance liquid chromatography (HPLC) was used to determine monomer release from the five polymers.
Objectives: The aim of this study was to use high-pressure high-temperature (HP/HT) polymerization to produce urethane dimethacrylate (UDMA)-triethylene glycol dimethacrylate (TEGDMA) based resin composite blocks (RCB) suitable for dental computer-aided design/manufacture (CAD/CAM) applications and to compare their physical/mechanical properties to those of a commercial dental RCB. The null hypotheses tested were: (1) there are no differences in the physical/mechanical properties between HP/HT polymerized UDMA-TEGDMA RCB and a commercial RCB; (2) volume fraction filler (Vf) does not affect the physical/mechanical properties of HP/HT polymerized RCB.
Methods: Four UDMA-based experimental RCB were manufactured under HP/HT conditions.
Objectives: Operative clinical trials are often small and open-label. Randomization is therefore very important. Stratification and minimization are two randomization options in such trials.
View Article and Find Full Text PDFA novel calcium phosphate silicate bone cement (CPSC) was synthesized in a process, in which nanocomposite forms in situ between calcium silicate hydrate (C-S-H) gel and hydroxyapatite (HAP). The cement powder consists of tricalcium silicate (C(3)S) and calcium phosphate monobasic (CPM). During cement setting, C(3)S hydrates to produce C-S-H and calcium hydroxide (CH); CPM reacts with the CH to precipitate HAP in situ within C-S-H.
View Article and Find Full Text PDFPurpose: The purpose of this study was to investigate if hydrophilicity influences the depth of penetration and the microleakage and to determine if the state of enamel, wet or dry, influences the wettability and sealing capacity of sealants.
Methods: HeliosealF, a hydrophobic sealant, and Embrace, a hydrophilic sealant, were tested. Sections were delimited on each of the polished enamel surfaces of 15 human molars to study the spreading of the selected sealants on wet or dry enamel; 40 molars were used to investigate the depth of penetration and microleakage on both dry and wet enamel.
Objectives: The aim of this study was to thermo-polymerize under high pressure four commercially available dental resin composites to obtain and characterize composite blocks suitable for CAD/CAM procedures.
Methods: Gradia (GC, Japan), Vita VM LC (Vita Zahnfabrik, Germany), Grandio (VOCO, Germany), and EsthetX (Dentsply, Germany), were selected for this study. Paradigm (3 M ESPE, USA), a CAD/CAM composite block, was included for comparison.
Introduction: The purpose of this study was to investigate, by using computational fluid dynamics (CFD), the effect of needle tip design on irrigant flow pattern.
Methods: Parameters of an in vitro irrigation model were used to create CFD models. Experimental data obtained by recording the dynamic fluid distribution during irrigation with 27-gauge notched (Appli-Vac) and side-vented open-ended (Vista-Probe) needles, placed at 3 and 5 mm from the apex of a simulated straight root canal prepared in a plastic block, were used to validate the results of CFD analysis.
Article Synopsis
- Root canal irrigation is crucial for cleaning and disinfecting the root canal system, and researchers aimed to develop a three-dimensional computational fluid dynamics (CFD) model to study this process.
- The study involved recording and analyzing the irrigation process in an in vitro model and validating it against CFD analysis with four different turbulence models.
- The findings revealed that the SST k-omega turbulence model closely matched the in vitro results, indicating limited irrigation reach in curved canals and distinct flow patterns at the needle outlet, suggesting the CFD model is effective for future root canal irrigation studies.
Introduction: The antibacterial effectiveness of 7 different endodontic sealers, AH Plus, Apexit Plus, iRoot SP, Tubli Seal, Sealapex, Epiphany SE, and EndoRez against Enterococcus faecalis was studied in vitro.
Methods: A modified direct contact test was used. Bacteria in suspension were exposed to the materials for 2-60 minutes by using sealers that were freshly mixed or set for 1, 3, and 7 days.