[Research of implant accuracy using a digital registration method].

Purpose: The aim of this study was to introduce a new method to evaluate the clinical accuracy of implant position. The results were compared to traditional cone beam CT (CBCT) method.

Methods: A total of 36 implants from 24 patients with sufficient bone volume were enrolled into the study.

Design of FRM-Based Nonuniform Filter Bank With Reduced Effective Wordlength for Hearing Aids.

This paper presents a design method for frequency response masking (FRM)-based nonuniform filter bank with reduced effective wordlength. Instead of designing prototype filters separately, we propose to model the filter bank design problem as a nonlinear programming problem and jointly design the prototype filters in the FRM structure. Moreover, in this work, all the filters are designed directly in the finite wordlength space, such that they can be directly implemented using efficient fixed-point arithmetic without any quantization.

Influence of different base materials and thicknesses on the fracture resistance of endocrown: A three-dimensional finite element analysis.

Introduction: To analyze the stress distribution of the all-ceramic endocrown with different base materials and thicknesses using three-dimensional finite element analysis.

Methods: A endodontically treated maxillary premolar was scanned by micro-CT, a three-dimensional finite element model of the endocrown with fluid resin as the base material was divided into control (0 mm), 1 mm, 2 mm, and 3 mm groups according to base thickness. Three kinds of conventional base materials were used and divided into glass ion group (A), fluid resin group (B), and nanocomposite resin group (C), and a three-dimensional finite element model of the endocrown with 1.

Dual-Band Dual-Mode Button Antenna for On-Body and Off-Body Communications.

A dual-band dual-mode button antenna for body centric communications is presented. At the lower band, a spiral inverted-F antenna is designed with omnidirectional radiation pattern for on-body communication. At the upper band, the high-order mode of the inverted-F antenna is utilized together with a metal reflector to realize broadside radiation for off-body communication.

[Effect of amount of silane coupling agent on flexural strength of dental composite resins reinforced with aluminium borate whisker].

Purpose: To evaluate the effect of amount of silane coupling agent on flexural strength of dental composite resins reinforced with aluminium borate whisker (ABW).

Methods: ABW was surface-treated with 0%, 1%, 2%, 3% and 4% silan coupling agent (γ-MPS), and mixed with resin matrix to synthesize 5 groups of composite resins. After heat-cured at 120 degrees centigrade for 1 h, specimens were tested in three-point flexure to measure strength according to ISO-4049.

Hybrid effects of zirconia nanoparticles with aluminum borate whiskers on mechanical properties of denture base resin PMMA.

The aim of this study was to investigate the hybrid effects of ZrO₂ nanoparticles (nano-ZrO₂) and aluminum borate whiskers (ABWs) on flexural strength and surface hardness of denture base resin, polymethyl methacrylate (PMMA). Both nano-ZrO₂ and ABWs were modified by silane coupling agent (Z6030) before being mixed with PMMA. Various amounts of silanized nano-ZrO₂ and ABWs were mixed with PMMA to prepare ZrO₂-ABW/PMMA composites.

[Effect of nano ZrO2 on flexural strength and surface hardness of polymethylmethacrylate].

Purpose: To study the effect of polymethylmethacrylate(PMMA's) mechanical properties reinforced by nano ZrO(2) particles with different filling amounts.

Methods: The nano ZrO(2) particles were surface-treated by silane coupling agent(Z-6030) in 1.5wt% ratio, the untreated particles were regarded as the control group.

[Microleakage of various cementing agents for casting ceramics].

Purpose: To observe and compare the microleakage of different composite resin cement systems for IPS Empress 2 ceramics base.

Methods: Sixteen healthy non-carious human molars were selected in the study. Class V ceramic inlay was prepared by IPS Empress 2 ceramics.

[Pedigree analysis and prosthodontic treatment of patients with dentinogenesis imperfecta type II].

Purpose: To study the heritable character and explore the prosthodontic treatment of opalescent dentin, also known as dentinogenesis imperfecta type II(DGI-II).

Methods: Pedigree analysis was performed in the family members of patients with DGI-II found in Shanghai. The proband was treated with ceramometal restorations and investigated the treatment status of the DGI-II affected individuals in the family.

[The effect of different dispersive methods on flexural strength nano-ZrO(2) reinforced denture polymethyl methacrylate].

Purpose: To study the effect of different dispersive methods on flexural strength of nano-ZrO(2)/polymethl methacrylate(PMMA) composite samples.

Methods: The nanometer ZrO2 particles which were modified by coupling agent Z-6030 were mixed to PMMA as the filler materials (3%) by means of handle disperse, ball milling disperse and ultrasonic wet disperse, respectively. Pure PMMA was used as blank control .

[Stress analysis of the all-ceramic crown with a numerical approach].

Objective: To analyze the stress distribution in all-ceramic crowns when it was subjected to load.

Methods: A 3D numerical model of the all-ceramic crown of the right mandibular first molar was generated from scanned CT images. Finite element analysis (FEA) was used to evaluate the stress distribution in the all-ceramic crown when it was subjected to 5 load conditions.

[Color distribution of the anterior teeth in 137 elder people].

Purpose: To study the color distribution of the anterior teeth in elder people.

Methods: 612 anterior teeth from 137 people aging from 60 to 81 years and 200 anterior teeth from 100 young people aging from 20 to 40 years were collected. A digital colorimeter was used to measure the value of L*,a*,b* of the teeth, and the chromatism (deltaE) was calculated according to the formula deltaE=(deltaL*(2)+deltaa*(2)+deltab*(2))1/2.

[Influence of time on shear strength using resin cements].

Purpose: To compare the shear bond strength of different composite resin cement systems at different time intervals.

Methods: 48 healthy non-carious human molars were selected in the study. The samples were divided into two groups, 24 in each group.

[Influence of different amount of silane coupling agent on the flexural strength of PMMA/nanometer ZrO2 composites].

Purpose: To study the influence of different amount of silane coupling agent Z-6030 on the flexural strength of PMMA/nanometer ZrO(2) composites.

Methods: Nanometer ZrO(2) particles were modified by silane coupling agent Z-6030 with different percentages.In situ polymerization method was used to combine PMMA/ nanometer ZrO(2) composites of denture base plate.

[The influence of the try-in pastes on the colour of all-ceramic veneers].

Purpose: To study the influence of the try-in pastes on the color of all-ceramic veneers made by Ips-empress II system.

Methods: 50 discolored teeth were collected and restored with all-ceramic veneers. Five try-in pastes including A1, A3, transleucent(Trt), white opaque(WOT) and B0.

[Clinical analysis of colour distribution in tetracycline teeth].

Purpose: To analyze the colour range and distribution of tetracycline teeth, and the difference from normal teeth.

Methods: 142 cases with 468 anterior tetracycline teeth and 100 cases with 200 normal anterior teeth were collected. The color was measured by a computer-aided Shade-Eye NCC colorimeter, and expressed in terms of 3 coordinate values (L,a,b) of the CIE-1976-Lab color system.

[Progress of research on fiber posts].

In the last few decades, casting metal has been the most commonly used post-core systems. But the elastic modulus of metal posts is higher than that of the dentin. Root fractures often happen because of the higher elastic modulus.

[Inducement and proliferation of MSCs in vitro and preliminary study on interface between MSCs and metal materials].

Objective: The aims of the present study were to assess the characteristics of MSCs which were induced and proliferated in vitro, then to learn the interfaces between them and metal materials.

Methods: Adult dogs were selected as experimental animals, the MSCs (marrow stem cells) were aspirated from the femur, which were induced to the phenotype of OB (osteoblast), then to proliferated in vitro with metal materials. Using biochemical tests, phase contrast microscopy, transmit electromicroscope, scanning electromicroscope to detect MSCs and the image of interface.

[Using moiré interferometre in the study of porcelain-fused-metal interfacial fracture mechanics].

Objective: To evaluate the usage of moiré interferometre in porcelain-fused-metal interfacial fracture mechanics.

Methods: Raster was produced on the surface of samples with different thickness of porcelain and metal in 5 groups. The stripes of u field and v field under different load were collected.