A study of the correlation between dental trauma and the personality of school-aged children / 实用口腔医学杂志

Objective: To study the influence of personality on the occurrence of dental trauma of school-aged children. Methods:The school-aged children with dental trauma who came to visit our department were randomly recruited. The Eysenck Personality Scale was used to test the subjects who met the inclusion criteria. Results: 306 children were included in the study. There was a statistically significant association between personality type and the number of traumatic teeth (P ＜ 0. 05) and the number of traumatic teeth in children with extroversion was higher than that of children with neutrality or introversion (P ＜ 0. 05) . Conclusion: Extroverted personality is a significant correlation factor affecting the severity of dental trauma in children, and it is of great significance to provide scientific guidance and warning for them to prevent tooth trauma.

A preliminary study on the determination of reference values of pulp viability in young incisors detected by laser doppler flowmetry / 实用口腔医学杂志

Objective: To study the clinical reference pulpal blood flow(PBF) values detected by laser doppler flowmetry(LDF) in healthy young population and to analyze their possible affected factors. Methods: Undergraduate students at the age of 17-23 years were enrolled. PBF of 12-22 were detected by LDF based on the standard procedure. Difference of the test results between different sex was analyzed by T test and variance homogeneity test, and the correlation with age was analyzed by the chi-square test, and the difference between the different teeth was analyzed by the random group analysis. Results: 400 students(250 males and 150 females with the average age of 19. 83 years) met the inclusion criteria. The clinical reference values of PBF of different anterior teeth were obtained by the detection of LDF. For the same tooth, PBF values of females were higher than that of males (P＜ 0. 05). PBF values of different ages shared no statistical significance(P＞ 0. 05). For the same gender, PBF values of middle incisor were higher than that of lateral incisors(P＜ 0. 05). Conclusion: The determination of the clinical reference values of PBF detected by LDF may promote the clinical use of this technology.

Quantitative detection of matrix metalloproteinase-2 in normal coronal dentine of young people / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To compare the distribution and concentration of matrix metalloproteinases-2 (MMP-2) in different dentin depth of premolar and molar of young people.</p><p><b>METHODS</b>Freshly extracted human premolars and molars (aged between 20-30) were sectioned to 1.5 mm thick slices along the longitudinal axis of the tooth separately. Enamel and pulp of each slice was removed, and then the premolar and molar slices were respectively divided into two subgroups according to superficial or deep dentin and pulverized to fine powder. After dentin protein was extracted, the concentrations of MMP-2 in different tooth were detected using fluorescent microsphere immunoassay.</p><p><b>RESULTS</b>The content of MMP-2 in superficial layer dentin of premolar was (0.022 ± 0.006) ng/mg. The content of MMP-2 in deep layer dentin of premolar was (2.087 ± 0.090) ng/mg. The content of MMP-2 in superficial layer dentin of molar was (0.336 ± 0.037) ng/mg. The content of MMP-2 in deep layer dentin of molar was (3.312 ± 0.308) ng/mg.</p><p><b>CONCLUSIONS</b>MMP-2 exists in human coronal dentin. In the same type of teeth of young people, the concentration of MMP-2 in deep dentin was significant higher than those in superficial dentin. In the same dentin depth, the concentration of MMP-2 in molar was significant higher than those in premolar.</p>

Effect of three aging challenges on the bonding stability of resin-dentin interface using an etch-and-rinse adhesive / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To systematically investigate the aging effect of thermocycling, water storage and bacteria aggression on the stability of resin-dentin bonds.</p><p><b>METHODS</b>Forty molars were sectioned perpendicularly to the axis of the teeth to expose the middle-coronal dentin surfaces. The dentin surfaces were then treated with Single Bond 2 and made a core build-up. According to random digits table, the bonding specimens were divided into four groups (n = 10) as follows: immediate control group, aging group with thermocycling for 5 000 times, aging group with artificial saliva storage for 6 months and aging group with bacteria aggression for 14 days. The specimens in each group were then subjected to microtensile bond strengths (µTBS) testing and nanoleakage evaluation respectively.</p><p><b>RESULTS</b>After aging treatments, the three aging groups showed significantly lower µTBS than the immediate control group [(44.24 ± 12.75) MPa, P < 0.05]. The immediate control group also showed the lowest value of nanoleakage. The µTBS of aging group with bacteria aggression [(25.53 ± 7.39) MPa] was significantly lower than those of the other aging groups with artificial saliva storage[(29.72 ± 6.51) MPa] and thermocycling [(31.92 ± 11.87) MPa, P < 0.05]. There were no differences in the nanoleakage values among the three aging groups (P > 0.05).</p><p><b>CONCLUSIONS</b>All the aging treatments with artificial saliva storage, thermocycling and bacteria aggression could accelerate the degradation of bonding interfaces between an etch-and-rinse adhesive and dentin. Bacteria aggression showed the most impairing effect on the stability of resin-dentin bonds.</p>