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Objective@#To observe the morphological changes of root canals in maxillary second premolars at various ages by using cone-beam CT (CBCT) in order to provide imaging and theoretical reference for clinical treatments.@*Methods@#The digital CBCT data of the maxillary second premolars in 440 cases from the patients in Department of Stomatology, The First Affiliated Hospital, Jinan University during March 2011 and December 2017 were collected. The CBCT images were divided into 4 groups according to the patients′ ages: groups ≤20, 21-40, 41-60 and>60 years old, respectively. Changes of morphologies of root canals with aging including such parameters as types of the root canal, incidence of double root canals in single rooted teeth, distance between both root canal orifices of double rooted canals, and morphological change of the cross section of roots. Chi-square test and liner trend test were adopted in statistical analysis in the present study.@*Results@#Most maxillary second premolars had only one root [95.2% (419/440)]. Type Ⅰ of the root canals was the most common type [57.3% (252/440)], and the following prevalent groups were type Ⅱ[16.8% (74/440)], type Ⅳ [10.2% (45/440)] and type Ⅲ [8.9% (39/440)]. The distribution of type Ⅰ~Ⅳ of the root canals were significantly different amongst various aged groups (P<0.05). Along with aging, the percentages of type Ⅰ decreased while type Ⅱ increased. However, there were no remarkable changes of type Ⅲ and type Ⅳ observed. The incidence of double canal in single rooted teeth gradually increased with aging especially in 20-year-old and above groups, e.g. 13.1% (13/99) in group of ≤20 years old and 45.0% (86/191) in group of 21-40 years old. However, there was no significant increase observed after the age of 40. The distance between two root canal orifices of double rooted canals became shorter with aging except in groups of 40-year-old and above. The morphologies of the cross sections of root canals in most groups were flat shaped [57.8% (1 121/1 938)] and oval shape [31.3% (607/1 938)]. Along with aging, the percentage of circular shape gradually increased while flat and oval shapes decreased.@*Conclusions@#The morphology of root canal could be clearly showed by the CBCT images. Most maxillary second premolars had only one root and one apical foramen. Along with aging, the morphology of the root canals became more and more complicated.
RÉSUMÉ
Objective:To investigate the correlation between root and root canal diameter of maxillary central incisors and age by cone-beam computed tomography(CBCT).Methods:CBCT images of 420 cases of Chinese Han population were divided into 7 age groups as follows:1 5 -24,25 -34,35 -44,45 -54,55 -64,65 -74 and 75 -84(n =60).Root diameter and root canal diameter of maxillary central incisors at the 3 /4 level from the cemenal-enamel junction(CEJ)to root apical were measured.Linear-regression a-nalysis was used to analyze the correlation between root and root canal diameter of the teeth and age,T-test was used to examine the gender difference.Results:Mean root diameter(mm)of the teeth in males and females were 5.81 ±0.445 and 5.53 ±0.489(P <0.05),mean root canal diameter(mm)1 .20 ±0.396 and 0.96 ±0.236(P <0.05),mean of the ratio of root canal diameter and root diameter of the teeth 0.21 ±0.072 and 0.1 7 ±0.043(P <0.05)respectively.There were negative correlations between the ratio of root canal diameter and root diameter of the teeth with age (R2 =0.576,P <0.05).Conclusion:The ratio of root canal diameter and root diameter of maxillary central incisors is negitively correlated with age in Chinese Han population.The decrease of root canal diame-ter in males is more significant than that in females.
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Aging changes of tyrosine hydroxylase (TH) -immuno reactive neurons in the locus coeruleus were examined in young (3 month-old). adult(12 month-old) and aged(20 month-old) Wistar male rats, using the IGSS method and image quantitative analysis. The results obtained are as follows: ① The number of TH-immunoreactive neurons docreased markedly (P
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The amount of gastrointestinal associated lymphoid tissue (GALT) of 99 cases of autopsy died from various accidents has been examined by Videoplan. The results showed that the density of GALT in appendix (0.24mm~2/mm-length of GIT) is the maximum, the next is in ileum (0.0941/mm~2/mm). Since the total area of ileum is much more larger than that of appendix, it is suggested that ileum may possess the primarily important immunefunction in GIT.No statistical difference of aging associated changes of the amount of GALT could be identified in this study, however, a tendency of decline existed. The factors related with this result were discussed.
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Aging changes of somatostatin (SS) mRNA-positive neurons in the dorsal hippocampus of old rats were studied by in situ hybridization histochemistry and image analysis. In the young rats,SS mRNA-positive cell bodies were mainly located in the pyramidal and polymorphic cell layers of the CA1 and CA2 regions, and in the strata radiatum and polymorphic cell layer of the CA3 region, and in the polymorphic cell layer of dentate gyrus. In the old rats,SS mRNA-positive cell bodies were concentrated in the polymorphic cell layer and denate gyrus. A marked decrease of number of SS mRNA-positive cell bodies and a significant increase of gray value of SS mRNA-positive cell bodies were found in the dorsal hippocampus and dentate gyrus of the old rats as compared with the young rats. No significant age difference in the sectional area of SS mRNA-positive cell bodies was observed in the dorsal hippocampus. The results showed that there were apparent changes with aging of the SS mRNA-positive cell bodies in the dorsal hippocampus of the rats. The significance of the changes remains to be studied further.
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Aging changes of neurotensin-like (NT-L) and galanin-like (GAL-L) cell bodies and fiber terminals in the central amygdaloid nucleus between the young and old rats were studied by means of immunohistochemical and microspectrophotometric techniques. NT-L cell bodies were mainly located in the central part (CeLn) of, centrolateral amygdaloid nucleus, a few of NT-L neurons were also found in the centrolateral amygdaloid nucleus, capsular part (CeLc) and centromedial amygdaloid nucleus (CeM). NT-L fiber terminals were seen mainly in the CeLn and CeLc. GAL-L cell bodies were observed only in the CeM. A marked decrease of density of NT-L cell bodies and fiber terminals in the central amygdaloid nucleus was found in the old rats as compared with young animals. No significant age difference in number of GAL-L cell bodies was observed in the central amygdaloid nucleus, but the staining intensity of GAL-L cell bodies was reduced remarkably. The results show that there are apparent changes with aging of the NT-L and GAL-L neurons in the central amygdaloid nucleus of the rat. The significance of the changes remains to be studied further.