Powder bed fusion-laser beam prepared Ti-6Al-4V/Ta bimetals can be well-suited for advanced biomedical applications. However, a few issues remain unsolved, including (a) understanding of residual stress distribution and its level in as-printed bimetal; and (b) wear and bio properties of the bimetal. This study aims to address these points through a series of investigations, including residual stress analysis by neutron diffraction, printing optimization, and analysis of heat treatment effect on the properties. It was discovered that the residual stress is highly related to the temperature gradient and Young's modulus. In the interface region of the as-printed bimetal, the residual stress was reduced and inverted compared to the as-printed Ta alone, changing from-(140-180) MPa (tensile) to-(30-70) MPa (compressive), which may have helped the Ta layer bond effectively with the Ti-6Al-4V matrix. Meanwhile, a high residual stress (- 390 MPa) in the Ti-6Al-4V part of the as-printed bimetal justifies the need for heat treatment. After heat treatment, the bimetal exhibited good biocompatibility and much improved wear and corrosion resistance compared to Ti-6Al-4V alone. These improvements may be attributed to the formation of tantalum oxide during friction and corrosion processes. Ta layer can also improve the biocompatibility due to its intrinsic noncytotoxic feature.

Aim or purpose: This study aims to assess the clinical effectiveness of a tripartite therapeutic strategy combining enamel microabrasion, at-home bleaching, and resin infiltration in addressing esthetic concerns associated with moderate to severe dental fluorosis. Materials and methods: Five individuals with moderate to severe dental fluorosis underwent a sequential protocol: enamel microabrasion, at-home bleaching, and resin infiltration. Post-treatment follow-ups spanned 1–5 years. Outcomes were evaluated via Visual Analogue Scale (VAS) for esthetic improvement, hypersensitivity incidence, and patient-reported satisfaction at 1 week, 6 months, and annually thereafter. Results: Immediate post-treatment (1 week) revealed marked reduction in enamel opacities, yellow discoloration, and surface pitting, with three cases demonstrating exceptional esthetic improvements. Longitudinal follow-up showed stable color and texture in two participants, while three exhibited minor color rebound. Transient sensitivity occurred in four patients during bleaching and two during resin infiltration. No hypersensitivity or adverse events were reported postoperatively. Patient satisfaction scores ranged from moderate to high across the cohort. Conclusions: The combined approach provided a conservative, patient-tolerated solution for moderate to severe dental fluorosis, yielding durable esthetic outcomes with minimal postoperative sensitivity. Longitudinal stability supports its clinical viability.

Laser powder bed fusion (L-PBF) produced commercial pure titanium (CP-Ti), which has great potential in oral healthcare. However, the effect of high-temperature environments (e.g., oral temperatures up to 60 degrees C during hot food intake) on its corrosion resistance remains unclear. Therefore, this work investigated the corrosion behavior and passive film characteristics of as-built and annealed CP-Ti in artificial saliva at 37 degrees C and 60 degrees C. As-built CP Ti consists dominated of alpha ' phase, while the annealed CP-Ti exhibits distinct grain boundaries with a mixture of alpha ' grains and sub-micron subgrains. Electrochemical tests conducted at 37 degrees C demonstrate that the annealed CP-Ti exhibits lower corrosion current density and higher film impedance than those of the as-built CP-Ti. Such a phenomenon is attributed to the lower diffusion coefficients and flux of oxygen vacancies in the passive film on the annealed CP-Ti. When the temperature rises to 60 degrees C, the annealed CP-Ti still shows better corrosion resistance than the as-built CP-Ti. The elevated temperature increases the migration of oxygen vacancies in the passive film, resulting in the enhanced growth and dissolution of the passive film on the samples. As investigated, the influence of temperature on the corrosion resistance of the samples obeys the Arrhenius equation.

The Ti-6Al-4V alloy is the most widely utilized titanium metal alloy globally, making the enhancement of its mechanical properties important. In this study, we achieved an ultimate tensile strength of 1.5 GPa through the additive manufacturing (AM) of Ti-6Al-4V. Specifically, the Ti-6Al-4V alloy was fabricated via laser powder bed fusion (L-PBF) using Ti-6Al-4V powder subjected to cold plastic deformation (CPD Ti-6Al-4V). The microstructural evolution of the Ti-6Al-4V powder during CPD was analyzed in detail. The CPD Ti-6Al-4V powder exhibited a core-shell structure with subgrains and nanocrystals formed via high-density dislocations within the shell. In addition, the as-printed CPD Ti-6Al-4V alloy had an average grain size of approximately 1.9 mu m. The presence of interstitial elements and finer grains resulted in the formation of Ti-6Al-4V alloys with ultrahigh strengths (ultimate tensile strength of approximately 1500 MPa, yield strength of 1320 MPa, and elongation of 6%). This groundbreaking achievement paves the way for further advancements in AM technology and presents exciting opportunities for innovation across a range of high-strength materials, which are crucial for achieving optimal performance. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

BACKGROUND:The edentulous patients with unstable mandibular position (MP) and uncoordinated mandibular movement (MM) usually complain the poor therapeutic effect when conventional complete dentures (CCDs) are delivered. This case report aims to observe whether neuromuscular training (NT) using therapeutic complete dentures (TCDs) can improve the MP and MM, thereby promoting the effect of the definitive dentures. CASE PRESENTATION:NT was conducted using TCDs for an edentulous patient with unstable MP and uncoordinated MM. After a period of masticatory exercises, the patient's MP and MM improved. Finally, the definitive dentures were delivered, achieving satisfactory results. CONCLUSION:NT with TCDs can improve unstable MP and uncoordinated MM, leading to successful rehabilitation in edentulous patient.

Pure metals tend to have a superior malleability compared to alloys. However, the applicability of pure metals is limited by their low strengths and hardness properties. In this study, strong and ductile pure Ti was synthesized via an approach involving powder modification and additive manufacturing (AM) under a reactive atmosphere. Specifically, pure Ti was processed by laser powder bed fusion in an environment containing a mixture of argon and nitrogen gases. In-situ high-energy synchrotron X-ray diffraction analysis reveals that in-situ nitrogen strengthening of the pure Ti occurs during the reactive AM of Ti. Furthermore, the presence of a nitrogen solid solution leads to the formation of high-strength pure Ti (yield strength of ∼979 MPa and ultimate tensile strength of ∼1058 MPa, respectively). This material exhibits excellent uniform elongation (11%) due to strong work hardening caused by the interaction of interstitial elements and submicrostructure. The proposed reactive AM approach paves the way for in-situ strengthening of pure metals and alloys.

Objective: To study the effectiveness of different surface treatments such as sandblasting and/or acid etching on the bond strength of selective laser melting pure titanium to composite resin. Methods: According to the ISO10477 standard, ninety-six selective laser melting pure titanium specimens were randomly divided into 4 groups and treated as follows: Group A1: grinding; Group B1: Sandblasting; Group C1: 4% hydrofluoric acid etching（HF）; Group D1: 4% HF acid etching after sandblasting（n=24）. Ninety-six forged titanium specimens from different processing technique were taken as the control groups, and the same surface treatments were done and recorded as A2, B2, C2, and D2（n=24）. After the surface treatments, a laser scanning confocal microscope was used to observe the surface morphology and roughness, the bond strength tests were carried out before and after the thermal cycles, and the mode of failures were observed by a stereo microscope. Results: The grinding group has the lowest roughness and the roughness of 4% HF acid etching after sandblasting was lower than that of sandblasting group（P＜0.05）. The bond strength of 4% HF acid etching after sandblasting group was about 4 times higher than that of grinding group（P＜0.05）, and the bond strength of the selective laser melting pure titanium specimens were（19.68±2.87） mPa and forged titanium specimens were（17.20±2.60） mPa. The bond strength between titanium and composite resin did not decrease significantly before and after the thermal cycling（P＞0.05）, and the durability was good. The fracture mode was mainly mixed fracture. Conclusion: Acid etching after sandblasting can effectively improve the strength of titanium to composite resin, which is one of the ideal methods for surface modification of selective laser melting titanium. It can significantly improve the bonding strength with composite resin and have good durability and can prolong the service life of the restoration to a certain extent at the same time. Selective laser melting titanium is a promising processing technology that can replace the traditional production of titanium for clinical applications.

Abstract Residual powder is a defect in powder bed fusion-based additive manufacturing (3D printing), and it is difficult to completely remove it from as-printed materials. In addition, it is not necessary to apply 3D printed implants with residual powder in the clinic. The immunological response triggered by the residual powder is an important area of study in medical research. To further understand the possible immunological reactions and hidden dangers caused by residual powders in vivo, this study compared the immunological reactions and osteolysis caused by typical powders for four implant materials: 316 L stainless steel, CoCrMo, CP-Ti, and Ti-6Al-4V (particle size range of 15–45 μm), in a mouse skull model. Furthermore, the possible immunological responses and bone regeneration induced by the four 3D printed implants with residual powder in a rat femur model were compared. In the mouse skull model, it was found that the 316L-S, CoCrMo-S, and especially the 316L-M powders, upregulated the expression of pro-inflammatory factors, increased the ratio of RANKL/OPG, and activated more functional osteoclasts, resulting in more severe bone resorption compared with those in other groups. In the rat femur model, which is more suitable for clinical practice, there is no bone resorption in implants with residual powders, but they show good bone regeneration and integration ability because of their original roughness. The results indicate that the expressions of inflammatory cytokines in all experimental groups were the same as those in the control group, showing good biological safety. The results answered some critical questions related to additively manufactured medical materials in vivo and indicated that as-printed implants may have great potential in future clinical applications. Graphical Abstract

PURPOSE:To evaluate the effect of surface treatment on bonding strength between pure titanium formed by selective laser melting and porcelain.METHODS:Pure titanium strips (64) and cobalt-chromium alloy strips (16) were laser machined to meet ISO 9693 standards. The pure titanium specimens were divided into 4 groups according to the sandblasting pressure and interlayer material. The sandblasting pressure of 0.25 MPa of bonder porcelain group was TB1, the sandblasting pressure of 0.25 MPa of gold coating group was TG1, the sandblasting pressure of 0.45 MPa of bonder porcelain group was TB2, and the sandblasting pressure of 0.45 MPa of the gold coating group was TG2(n=16). After porcelain fusing, half of the specimens in each group were tested for three-point bend bonding strength, and the other half were tested after 10 000 cycles of thermal cycling(n=8). The bonding strength of cobalt-chromium alloy after sandblasting at 0.25 MPa and 0.45 MPa was taken as the control group and recorded as group C1, C2(n=8). The bonding strength was tested using classical three-point bending experiment. The surface roughness of pure titanium was measured by laser scanning confocal microscope(LSCM). Field emission scanning electron microscopy(FE-SEM) was used to observe the interface morphology of titanium-ceramic. The surface morphology of titanium after porcelain stripping was observed with stereomicroscope and fracture modes were analyzed by it. Graphpad Prism 8.0 software package was used for statistical analysis of the data.RESULTS:The bonding strength of group TG2 was (40.16±3.97) MPa and (37.38±2.39) MPa of group TG1, which were significantly higher than that of group TB2 (36.32±1.44) MPa and group TB1 (33.75±2.31) MPa (P＜0.05). The bonding strength of group TB2 with 0.45 MPa sandblasting was significantly higher than that of group TB1 with 0.25 MPa sandblasting (P＜0.05). There was no significant decrease in titanium-ceramic bonding strength before and after thermal cycling. When the sandblasting pressure increased from 0.25 MPa to 0.45 MPa, the roughness increased significantly (P＜0.05). The fracture modes were mixed.CONCLUSIONS:Under the conditions of this study, gold coating can significantly improve the bonding strength of Ti22 porcelain and SLM pure titanium than bonder porcelain, and increase of sandblasting pressure can further improve the bonding strength of titanium-porcelain. After 10 000 cycles of thermal cycling, the titanium-porcelain bonding strength did not decrease significantly.

Titanium meshes are widely utilized in alveolar bone augmentation, and this study aims to enhance the properties of titanium meshes through heat treatment (HT) and the synergistic finishing technology of electric field and flow field (EFSF). Our findings illustrate that the titanium mesh exhibits improved mechanical properties following HT treatment. The innovative EFSF technique, in combination with HT, has a substantial impact on improving the surface properties of titanium meshes. HT initiates grain fusion and reduces surface pores, resulting in enhanced tensile and elongation properties. EFSF further enhances these improvements by significantly reducing surface roughness and eliminating adhered titanium powder, a byproduct of selective laser melting printing. Increased hydrophilicity and surface-free energy are achieved after EFSF treatment. Notably, the EFSF-treated titanium mesh exhibits reduced bacterial adhesion and is non-toxic to osteoblast proliferation. These advancements increase its suitability for clinical alveolar bone augmentation.

In esthetic rehabilitation, methods used to enhance the margin quality have always been the focus and difficulty of improving the level of diagnosis and treatment, prevention and treatment of complications, and collaboration between clinicians and technicians. However, it is impeded by the ambiguous definition and classification of margin, unstandardized tooth preparation, manufacturing process of restoration, and lack of reliable means of checking the quantitative requirements of preparation or restoration. The digital technologies that are increasingly applied, such as intra-oral scanner, impression scanner, and computerized numerical control cutting machine, have strict requirements about margin quality. Failure of recognizing margins by these scanners will hinder the digital process of diagnosis and treatment. Even if these sharp and narrow margins are successfully scanned, they cannot be milled accurately. To overcome these problems, this article demonstrated the clear and complete definition of preparation margin and restoration margin, as well as their subclassifications, by analyzing the target restoration space from a geometric perspective. Practical approaches to measuring the margin width and inspecting the margin quality were proposed. The new and full understanding and proposal about preparation margin and restoration margin characterized by measurements will effectively support the thoroughly digitalized process of esthetic rehabilitation using porcelain in fixed prosthodontics, which is based on the guidance of values.

Objective To evaluate the effect of heat treatment on the bonding strength of pure titanium formed by selective laser melting (SLM) and porcelain. Methods Ninety-six pure titanium specimens were laser machined to meet ISO 9693 standards. The specimens were divided into a heat treated group (A) and a nonheat treated group (B). According to the porcelain type, the specimens in groups A and B were divided into Super Ti22 (a), Titankeramik (b), and Triceram (c) groups. Then, according to sandblasting pressures of 0.25 MPa (1) and 0.45 MPa (2), they were further divided into Aa1, Aa2, Ab1, Ab2, Ac1, Ac2, Ba1, Ba2, Bb1, Bb2, Bc1, and Bc2 groups. The surface morphology and roughness of the sandblasted specimens were assessed using a laser scanning confocal microscope. After the porcelain was fused, the three-point bending titanium-porcelain bonding strength was tested. A stereomicroscope was used to characterize the titanium-porcelain interfaces and determine the mode of failure. Results The Vickers hardness of group A specimens (188.21 ± 11.94) was significantly lower than that of group B specimens (204.48 ± 6.32) HV (P<0.05). The roughness value in group A1 (2.90 ± 0.32) μm was significantly lower than that in group A2 (3.43 ± 0.43) μm (P<0.05). Specimens in group B1 (2.62 ± 0.08) μm were significantly smaller than those in group B2 (3.01 ± 0.06) μm (P<0.05). The bonding strength in group Aa1 was (33.75 ± 2.31) MPa, group Aa2 was (36.32 ± 1.44) MPa, group Ab1 was (39.82 ± 2.28) MPa, group Ab2 was (33.74 ± 1.53) MPa and group Ac2 was (38.63 ± 1.36) MPa, which was significantly higher than that in the corresponding groups Ba1 (29.65 ± 1.10) MPa, Ba2 (27.17 ± 2.24) MPa, Bb1 (27.29 ± 1.61) MPa, Bb2 (23.85 ± 0.97) MPa, and Bc2 (35.75 ± 1.93) MPa (P<0.05). With increasing sandblasting pressure, the bonding strength of the titanium ceramic in group Aa2 was significantly higher than in group Aa1, while that in group Ab2 was significantly lower than that in group Ab1 (P<0.05). In groups A, Bc1 and Bc2, the fracture model showed mixed failure, while in groups Ba1, Ba2, Bb1, and Bb2, the model showed interfacial failure. Conclusion The Vickers hardness of SLM titanium can be significantly reduced by heat treatment. SLM pure titanium after heat treatment is beneficial to combination of the three porcelain types and titanium. The titanium-porcelain bonding strength may be affected by sandblasting pressure.

Objective:To investigate the accuracy of pure titanium and cobalt-chromium alloy frameworks fabricated using the additive manufacturing (AM) of selective laser melting technology (SLM) for the mandibular implant-supported fixed prostheses and the maxillary removable partial denture (RPD), and to provide a reference for clinical application of SLM pure titanium frameworks.Methods:One edentulous mandibular model with implants and screw fixed abutments at bilateral canines and the first molars was selected and used as the mandibular full arch implant-supported model. At the same time, a Kennedy class Ⅰ maxillary dentition defect model was selected. The digital models were obtained by scanning the dental models, and the metal frameworks of the mandibular full arch implant-supported denture and the maxillary RPD (design model) were designed using the 3 Shape software. Meanwhile, 12 mandibular frameworks in the cobalt-chromium alloy and the pure titanium (6 in each group were treated with heat treatment, while the other 6 were not treated), and 7 maxillary frameworks in the cobalt-chromium alloy and the pure titanium were respectively made by SLM with the improved dual-laser metal printer. The axial direction of the printing powder accumulation was taken as the Z-axis. During the design process, the software (3Shape Dental System 2018) automatically generated the X-axis and Y-axis, X axis was the sagittal axis of the dental model and Y axis was the coronal axis of the dental model. The deviation of the interface center of the abutment of the digital model of the mandibular frameworks from the design model in the X, Y and Z axes was analyzed. As for the trueness of the mandibular framework, the larger the deviation data was, the worse the trueness was. The deviation of the whole maxillary framework and 7 measuring points (palatal plate center point and bilateral occlusal rests, I bars, proximal plates) were analyzed. The fitness of the whole maxillary framework to the design model was expressed by root mean square (RMS) of the deviation data, and the fitness of measuring points was expressed by the mean±standard deviation of the data. The trueness differences of each group before and after heat treatment of the mandibular framework and the fitness of the maxillary framework were compared.Results:The cobalt-chromium alloy frameworks showed lower trueness on the X, Y, Z-axes [(96.3±12.1), (86.3±11.4), (61.2±13.2) μm] than did the pure Ti frameworks [(82.3±11.2), (72.2±10.2), (51.2±11.6) μm] by SLM, and the heat treatment could reduce the discrepancy between the SLM frameworks and STL models, for pure titanium frameworks [(62.4±11.3), (55.2±13.2), (41.3±10.8) μm] and for cobalt-chromium alloy [(84.5±10.5), (72.3±11.2), (54.2±11.6) μm]. For the thin RPD major frameworks, pure titanium had better fitness [(121.3±17.0) μm] than cobalt-chromium alloy [(174.0±18.3) μm] by SLM, and the difference was statistically significant ( P<0.05). Conclusions:Pure titanium frameworks fabricated by SLM additive manufacturing technology exhibited better fitness and trueness than did the Co-Cr frameworks after heat treatment respectively, and this satisfied the requirements of implant-supported fixed prostheses and RPD major metal frameworks.

Objective To evaluate the effect of different surface treatments on the bonding strength between highly translucent zirconia and veneering porcelain and to provide a research basis for improving the zirconium porcelain bond strength between zirconium and ceramic material.Methods Thirty cylindrical zirconia blocks with 10-mm diameter and 10-mm height were prepared and divided into four groups (n=7), labeled as control group (C), sandblasting group (S), bonding group (B), and sandblasting and bonding group (SB). The surface morphology of zirconia before and after sandblasting was observed in the remaining two specimens. Group C was veneered (2 mm in height and 5 mm in diameter) with porcelain powder by layering after grinding. Group S was sandblasted after grinding. Group B was veneered with a thin layer of porcelain powder as bond coating. Group SB was sandblasted and veneered with a thin layer of porcelain powder. After sintering, the shear specimens were embedded, and a shear bond strength test was conducted. Statistical analysis was conducted to analyze the data. Fracture surface analysis was also performed to determine the failure modes by stereomicroscopy.Results The bonding strength of group C was 21.86 ± 3.18 MPa. For group S, it was 22.12 ± 3.06 MPa. For group B, it was 19.19 ± 1.46 MPa. Finally, for group SB, it was 27.76 ± 1.95 MPa. There was no significant difference in shear strength between group C, group S and group B. There was a significant difference in shear strength between each group and group SB (P < 0.05). Under a stereomicroscope, the observed fracture modes of each group were mainly mixed failure.Conclusion Sandblasting cannot significantly increase the bonding strength between zirconia and veneering porcelain. Veneering with a thin layer of porcelain powder as the bond coating has no obvious effect on the bonding strength. Sandblasting and veneering with a thin layer of porcelain powder as a bond coating can significantly improve the bonding strength between zirconia and veneering porcelain.

An 80-year-old man sought treatment at our hospital. He was dissatisfied with his old complete denture due to its poor stability and retention. The old complete denture had been used for about 20 years. The prolonged use of an unsuitable complete denture led the patient to be accustomed to unilateral mastication (UM). Due to the patient long-term habitual mandibular deviation, using the physiological technique to get the centric relation (CR) achieved an incorrect horizontal maxillomandibular record. This clinical report presents a technique using the existing complete denture mounted with a Gothic arch tracer to determine the CR. This technique is an inexpensive, simple, and reliable method that allows fabricating the final impression and obtaining the maxillomandibular relationship record (MMRR) in one step.

牙隐裂是临床中较为常见的疾病,是继牙周病、龋病引发成年人牙缺失的三大主要病因之一[1].牙隐裂早期常因症状不明显、患者主诉模糊而难以准确诊断,待症状明显时,大多患牙已需要行根管治疗或直接拔除[2].因此,尽量保留隐裂患牙成为临床治疗的难点.目前,牙隐裂的治疗包括牙尖磨改、树脂粘接裂纹、树脂或银汞合金嵌体修复及全冠修复等,但尚无统一的治疗原则[3-4].

目的:观察低频重复经颅磁刺激方法治疗夜磨牙症的效果.方法:选择30名夜磨牙患者,先在正中矢状面旁9 cm、正中冠状面前4 cm左右,通过前后和左右的微移来确定最终能引起连续5个运动诱发电位的最小磁刺激强度所在的热点即hot spot,该最小磁刺激强度的值,即运动阈值(Active motor threshold,AMT).然后在hot spot给予1 Hz(90％AMT)低频重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)进行治疗,左右每侧各20 min,共40 min,连续进行7 d.在治疗前两天和治疗后,给患者佩戴夜磨牙检测垫观察牙齿磨动的情况;同时对患者的咬肌浅、深层及颞肌前、中、后份进行触诊,让患者对触诊疼痛的程度进行评分.结果:治疗前,夜磨牙检测片上色素被磨除区域的面积、咬肌浅、深层,颞肌前、中、后份的触诊疼痛评分均无统计学差异.经过7 d低频rTMS治疗后,夜磨牙检测垫上色素被磨除区域的面积、咬肌浅、深层,颞肌前份的评分均显著下降(P<0.05);颞肌中、后份的评分无显著改变.结论:低频rTMS可以减少夜磨事件的发生,对夜磨牙症有治疗作用,可以在临床推广使用.

Objective: To investigate the preventive effect of resin infiltration and adhesive on early erosive enamel wear. Methods: Orthodontic reduction premolars collected from Central Laboratory of Nanjing Stomatological Hospital, Medical School of Nanjing University were used to prepare 70 specimens. Forty samples were divided into eight groups (n=5) and treated with different conditions (pH=1.6, 2.4, 3.2 or 4.0 hydrochloric acid solution, etching time was 30 or 60 s), and the conditions for obtaining early erosive enamel samples were selected. Based on this procedure, thirty early erosive enamel samples were made and divided into three groups: control group, resin infiltration group, and adhesive group. And the treatment of 30 days acid abrasion cycle was carried out. Confocal microscopy was used to measure the thickness changes of enamel or material before and after cycle. Results: Early erosive enamel samples was obtained when pH was 4.0 and etching time was 60 s. After 30 days cycle, the wear of enamel was (29.71±6.72) μm in control group, (5.60±2.24) μm in resin infiltration group and (2.89±1.03) μm in adhesive group. In infiltration group and adhesive group, lower enamel was not affected by the cycle, and the material loss ratios of the infiltration resin group and adhesive group were 0.41±0.14 and 0.29±0.13, respectively. The ratio of material loss was not significantly different (P>0.05). But infiltration group lost (12.95±2.22) μm of enamel during the application of the material. Conclusions: Resin infiltration and adhesive have the same short-term protective effect against early erosive enamel wear. Adhesive has less damage to enamel and better effect.

Objective To study the effect of sputtering gold coating on the bonding strength between pure titanium and two low-fusing porcelains according to the protocol of ISO 9693,and to characterize the titaniumporcelain interfaces.Methods Forty machined pure titanium samples were prepared according to the ISO 9693 protocol.Based on the type of sintering porcelains (SP:Super Porcelain Ti-22;TC:Triceram) and titanium base with or without sputtering gold (Au),forty titanium samples were divided equally into four groups (AuSP,AuTC,SP and TC group).Low-fusion dental porcelain was then sintered onto the titanium samples.Three-point bending test was performed to assess the bonding strength,and optical stereomicroscope was used to characterize the titanium-porcelain adhesion and determine the failure mode.The titanium-ceramic interface was examined by Field Emission Scanning Electron Microscope (FE-SEM) and Electron Micoporbe Analysis (EMPA).Results The bonding strength of the AuSP groups was much higher than that of the SP groups (P＜0.05),while no significant difference was found between AuTC group and TC group (P＞005).The SP,AuTC and TC groups showed predominately adhesive fracture,whereas the failure mode of AuTC group was mixture of cohesive and adhesive,mainly cohesive.FE-SEM with EMPA did not show visible cracks in the Au groups.The depth of titanium and oxygen diffusion was decreased in the presence of the gold coating.Conclusions Sputtering gold intermediate coatings can inhibit titanium and oxygen diffusion,improve the bonding strength between Super Porcelain Ti-22 system,but does not affect the bonding strength of Porcelain Triceram system.

酸蚀性牙齿磨损(erosive tooth wear),俗称酸蚀症,是指化学和机械因素导致的牙体硬组织进行性丧失,各种内外源性酸作用于易感的牙齿是引起酸蚀症的主要原因 [1] 。近年,随着修复材料及现代粘接技术的发展,越来越多的学者选择微创的方式对酸蚀症患者进行咬合重建治疗 [2] 。本文介绍1例胃食管返流导致牙列重度磨损的酸蚀症患者微创