Preliminary application of three-dimensional printing in dental education / 中华口腔医学杂志

As one of the rapid prototyping technology, three-dimensional (3D) printing is booming since its birth. 3D printing has already been applied in biomedical engineering, medical mold processing and many healthcare fields, but its application in dental education is still in the exploratory stage. Nowadays, educators are seeking to integrate 3D printing and dental education. On the basis of the advantages of 3D printing, the quality of dental education will be further improved and students′ enthusiasm for learning will be stimulated. This article will focus on elaborating the recent advances of 3D printing in dental education and exploring its direction in the field of teaching.

Advances of self-healing dental composite resin / 中华口腔医学杂志

Degradation of composite resin during ageing always produces micro-cracks, the latter could gradually expand, leading to the fracture of tooth restoration. In order to extend the service life of composite resin by repairing cracks intelligently, self-healing microcapsule models have been introduced in resin-based dental materials. This paper will present the concept and classification of self-healing materials, and review the research progresses on self-healing dental resin.

Effect of a nano hydroxyapatite desensitizing paste application on dentin bond strength of three self-etch adhesive systems / 中华口腔医学杂志

Objective@#To evaluate a nano-hydroxyapatite (nano-HA) desensitizing paste application on the bond strength of three self-etch adhesives.@*Methods@#Three dentin specimens of about 1 mm thick were cut from two teeth. Scanning electron microscope (SEM) was used to evaluate the dentin surfaces without treatment, after citric acid treatment and after nano-HA treatment. Thirty-six intact third molars extracted for surgical reasons were cut to remove the occlusal enamel with isomet, and then were etched with 1% citric acid for 20 s to simulate the sensitive dentin and divided into two groups randomly using a table of random numbers (n=18): the control group (no treatment) and the HA treated group (with nano-HA paste treatment). Each group was divided into three subgroups randomly using a table of random numbers (n=6). Subgroup A, B and C was bonded with G-Bond, Clearfil S3 Bond and FL-Bond Ⅱ according to the manufacture's instruction separately. At 24 h after bonding procedure, and after water storage for 6 months, microtensile bond strength of the specimens was tested and the failure mode was analyzed.@*Results@#SEM obeservation showed that citric acid could open the dentin tubules to set up the sensitive dentin model, and the nano-HA could occlude the dentin tubules effectively. For subgroup A, bonding strength of specimens treated with nano-HA ([41.14±8.91] MPa) was significantly high than that of the control group ([34.27±6.16] MPa) at 24 h after bonding procedure (P<0.05). However, after 6 month water ageing, the bonding strength of the control group and the HA treated group showed no significant difference (P>0.05). For subgroup B, specimens with nano-HA application showed lower bonding strength ([30.87±6.41] MPa) than that of the control group ([36.73±5.82] MPa) at 24 h after bonding procedure (P<0.05), and after 6 month water ageing, the bond strength of nano-HA application ([25.73±6.99] MPa) was also lower than that of the control group ([32.33±5.08] MPa) (P<0.05). For subgroup C, the bond strength of the control group and the HA treated group have no significant difference either before or after 6 month water ageing (P>0.05). Failure mode analysis showed that more than half of the samples in all groups were adhesive failure.@*Conclusions@#Nano-HA treatment decreased the bond strength of subgroup B, while had no adverse effect on subgroup A and subgroup C.

Surface characterization of morphology and nano-scale adhesionforce on ethanol saturated root dentin / 西安交通大学学报(医学版)

Objective To observe the morphology of ethanol-wet dentin surfaces and detect their nano-scale adhesion force (Fad) by atomic force microscopy (AFM) in order to explore the potential mechanism of ethanol-wet bonding in improving clinical dentin bonding effectiveness.Methods Dentin slices from human premolar roots were prepared into flat ones, polished, and then randomly divided into five groups.All the specimens were acid-etched, rinsed, and left moist.They were then treated with 100％ ethanol for 0s (control group), 20s, 60s, 3×60s, or stepwise ethanol application.Afterwards, each group was scanned for the morphology in air and the Fad was probed by AFM.One-way ANOVA followed by Tukey`s test was employed for multiple comparisons using SPSS16.0.Results Compared with control group, ethanol-wet dentine produced a less undulating and relatively smooth surface topography.Ethanol-wet protocol significantly decreased the value of Fad in the experimental groups (P0.05).Conclusion When using AFM in air, ethanol-wet protocol with longer time can produce a less undulating and relatively smooth surface topography and decrease the Fad, whichindicates that the water saturated in dentin matrix was replaced more thoroughly by longer ethanol application time.This will benefit hydrophobicity of the dentin bonding interface.

The application of universal adhesives in dental bonding / 中华口腔医学杂志

The bonding restoration has become an important clinical technique for the development of dental bonding technology. Because of its easy operation and the maximum preservation of tooth tissues, bonding repair is widely used in dental restoration. The recent multi-mode universal adhesives have brought new progress in dental bonding restoration. In this article the universal adhesives were reviewed according to its definition, development, improvement, application features and possible problems.

Study of pretreatment with ethanol to compensate premature volatilization of self-etch adhesive system / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of pretreatment with ethanol on dentin to compensate premature volatilization of self-etch adhesive system.</p><p><b>METHODS</b>Thirty-two intact human molars were randomly divided into two groups using a table of random numbers (n = 16): A, an acetone-base adhesive (G-bond) and B, an ethanol-based adhesive (Clearfile S(3) bond). Then each group was randomly assigned into foursub groups (n = 4) : group 1, no premature volatilization; group 2, premature volatilization; group 3, premature volatilization + stepwise ethanol pretreatments; and group 4, premature volatilization + absolute ethanol treatment. After composite resin building, microtensile bond strengths (MTBS) of each subgroup were then tested. Fracture modes were classified by stereomicroscopy and representative interface was observed by field-emission scanning electron microscopy (FE-SEM).</p><p><b>RESULTS</b>For adhesive A, there was significant difference on MTBS among different subgroups (P < 0.05); the MTBS of group A2 [(26 ± 12) MPa] and A4 [(27 ± 7) MPa] was lower than that of group A1 [(41 ± 11) MPa] and A3 [(40 ± 11) MPa] (P < 0.05). No significant different was found between group A2 and A4 (P > 0.05); neither between group A1 and A3 (P > 0.05). For adhesive B, there was no difference on MTBS among different subgroups (P > 0.05).FE-SEM showed that the main fracture mode was located at the bottom of the hybrid layer for adhesive A groups, the collagen fibrils were capsulated by resin monomers more densely in group A1 and group A3 in comparison with other two subgroups.For adhesive B groups, the main failure modes were at the top of the hybrid layer.</p><p><b>CONCLUSIONS</b>Premature volatilization can obviously decrease the bonding strength of acetone-base self-etch adhesives, but has no significant effect on ethanol-based self-etch adhesives. Dentin pretreatment with a series of increasing ethanol concentrations can effectively compensate the adverse effect of premature volatilization of acetone-base self-etch adhesives on bonding strength.</p>

Research in effect of entire process nursing intervention during nebulization treatment of acute wheezing episodes in school-age children / 中国实用护理杂志

Objective To explore the effect of entire process nursing intervention during nebulization treatment of acute wheezing episodes in school-age children.Methods One hundred and forty-one children with acute wheezing episodes were divided into the experimental group (75 patients) and the control group (66 patients) by whether willing to accept nursing intervention or not,respectively.Routine nursing such as cognition of wheezing knowledge and respiration instruction was given to both groups,while specialists accompanied the whole procedure of inhalation treatment and they gave nursing intervention such as respiration,saliva swallow,expiration through nose,grasp of inhalation tank and body position maintenance to the experimental group.The improvement of wheezing and subjective sense by the patients,transcutaneous oxygen saturation (SaO_2),and the compliance of patients were measured and evaluated.Results Improvement of wheezing and comfort feeling were found in 97.3% of the experimental group,while 80.3% of the control group.And SaO_2 value (higher than 95%) was 92.0% in the experimental group,75.8% in the control group.The compliance of the experimental group was also better than the control group.Conclusions Entire process nursing intervention during nebulization treatment can improve clinical effect and the compliance of wheezing children.