上下颌牙齿磨耗推断年龄准确性的比较

目的利用牙齿磨耗不同的分类方法分别推断上、下颌的牙齿年龄,分析各种方法推断上、下颌牙齿年龄的误差,评价上、下颌牙齿用于年龄推断的准确性。方法采用分级法与数量化法分别对164名18~46岁之间的成年人进行牙龄推断,计算出推断牙龄与实际年龄的误差,输入SPSS软件对误差的数据进行统计学分析。结果分别使用不同方法对上、下颌牙齿磨耗程度进行年龄推断的结果差别不大。结论上、下颌牙齿用于牙齿磨耗推断年龄的准确性无明显差异。     

重庆地区汉族未成年人牙龄推断的研究

目的运用牙齿曲面断层影像技术,研究6周岁～15周岁重庆市未成年人牙齿钙化的规律,从而建立根据牙齿钙化程度推断年龄的方法。方法依据牙齿钙化分级标准对1321名（男性577名,女性744名）重庆市6周岁～15周岁未成年人牙齿曲面断层片上的牙齿钙化程度进行分级评分;将评分值与对应的性别和年龄分别输入SPSS13.0软件进行统计分析,最终建立推断年龄的方程。结果左右侧同名牙齿钙化程度无统计学差异（P〉0.05）,但性别间有统计学差异（P〈0.05）;下颌左右侧8颗牙齿的钙化程度与年龄相关系数均大于0.58;所建利用不同牙齿组合推断年龄的线性回归模型调整拟合优度均大于0.67,估计值标准误男性为0.95周岁～1.11周岁、女性为1.02周岁～1.12周岁。结论该方法可用于法庭科学领域中推断重庆市6周岁～15周岁未成年人活体以及尸体的年龄。     

中国黑龙江地区汉族未成年人的牙钙化程度及年龄推断

目的探讨未成年人牙齿钙化程度与其年龄的关系,建立根据牙齿钙化程度推断未成年人年龄的方法。方法拍摄黑龙江地区1510名未成年人（男737名,女773名,年龄6～15周岁）牙齿曲面断层影像片,利用计算机观察全口曲面断层影像片中下颌恒牙牙位处钙化程度的影像特征,并建立牙齿钙化分级评分标准,然后根据此标准对下颌牙齿进行分级评分;将其结果输入SPSS13.0软件统计,按α=0.05对牙齿钙化分值分性别分年龄段组进行非参数检验和与年龄的相关性分析,最终建立根据牙齿钙化程度推断年龄的回归方程。结果同名牙左右侧无差异（P〉0.05）,而性别间有差异（P〈0.05）;男女性下颌牙齿的钙化程度均与年龄高度相关（r〉0.7）;所建方程模型合理可靠,盲测结果显示推断年龄与实际年龄间无统计学差异,误差绝对值的平均值男性为（0.367±0.257）岁,女性为（0.367±0.245）岁。结论本研究中未成年人牙齿钙化程度随年龄的增长而呈现增高趋势,直至完全钙化;根据牙齿钙化程度建立的回归方程可用于未成年人活体以及无名尸体的年龄推断。     

CBCT技术研究进展及其在牙龄推断中的应用

牙齿是人体最坚硬的器官,不易因外界理化因素的变化而降解、变形,利用牙齿推断年龄已广泛应用于法医学。通过牙齿影像推断年龄是过去使用最普遍的方法之一,而锥形束计算机体层摄影术(cone beam computed tomography,CBCT)技术的出现为牙齿三维影像的获取提供了新途径,具有照射剂量低、扫描时间短、成像精度高及费用低等优点。本文综述了CBCT技术的研究进展及其在牙龄推断中的应用。     

应用放射影像技术进行牙龄推断

牙龄是年龄推断的重要方法之一，国外学者常将其与骨龄联合应用以提高年龄推断的准确性，但国内尚未普遍开展。大量研究表明，应用放射影像学这一无创的检查手段，可以准确观察牙齿的增龄性变化，如牙冠与牙根的发育程度、牙髓腔的变化等。目前应用放射影像学进行牙龄推断的主要方法有Gleiser和Hunt法、Demirjian法及牙髓腔测量法等。其中Demirjian法的准确性最高，但在推断法定敏感年龄时尚存在局限性。随着放射影像学的发展，尤其是CT的出现，依赖其高分辨率以及相匹配的测量软件，可提高牙龄推断的准确性与可靠性，有望成为今后推断活体年龄的重要手段。     

中国汉族6～18周岁人群下颌恒牙钙化的性别差异研究

目的通过对中国汉族男女6～18周岁人群全口曲面断层影像上所显示的下颌左侧牙齿钙化程度进行比较研究,探究牙齿生长发育的性别差异,为建立用牙齿推断中国汉族儿童及青少年年龄的线性回归模型提供理论依据。方法通过对13491张(男6568张,女6923张)中国汉族6～18周岁儿童及青少年全口曲面断层影像的牙齿钙化规律进行研究,建立牙齿钙化的分级标准,并对下颌恒牙进行分级评分;数据用SPSS 13.0软件处理。结果非参数检验结果显示大部分年龄组下颌左侧8颗恒牙钙化分级值性别间的差异有统计学意义(P0.05);在8颗恒牙发育程度同等条件下,女性年龄比男性小0.303岁。结论中国汉族6～18周岁人群牙齿发育存在着性别差异;在利用牙齿钙化程度建立推断中国汉族儿童及青少年年龄的方程模型时,应分性别建模。     

中国汉族6-18周岁男性牙齿生长发育的年龄研究

目的研究牙齿钙化程度与年龄的关系,建立利用牙齿钙化程度推断中国汉族6～18周岁男性年龄的办程。方法通过对6568名6～18周岁汉族男性全口曲面断层影像上牙齿的钙化程度进行评分;将分级值及其对应年龄输入SPSS软件进行分析,建立推断年龄的方程模型;从研究样本外随机抽取已知年龄的样本160例进行卣测,,结果同名牙齿钙化评分值侧别间秩合检验结果P〉0．05;下颌左侧恒牙钙化评分值与年龄相关分析结果r值均存0．7以上,下颌同名牙间相关系数r均在0．9以上;所建回归模型拟合优度R^2=0．828,估计值标准误为1．23岁;阿测平均洪差为0．423±0．269岁。结论本研究所建立的方法准确可靠,可用于中国汉族6～18周岁男性人群的年龄推断。     

利用牙齿推断死后经过时间的研究进展

死后经过时间推断一直是法医学研究的重点和难点。牙齿作为个体死后可以保存最久的生物检材之一,目前在死亡时间推断方面的利用程度并不高。近年来,随着法医牙科学的兴起,国内外研究者们利用大体形态学、病理组织学、分子生物学等方法探究了牙齿与死后经过时间的关系。本文综述了近年来利用牙齿推断死后经过时间的研究进展,总结其在法医学死后经过时间推断中的潜在应用价值,以期为早日实现利用牙齿推断PMI提供参考。     

中国汉族6～18周岁女性人群牙齿生长发育的年龄研究

目的研究牙齿钙化程度与年龄的关系,建立利用牙齿推断中国汉族女性人群年龄的方程。方法通过对6923名6～18周岁汉族女性儿童及青少年全口曲面断层影像下颌恒牙的钙化程度进行评分;将分级值及其对应的年龄输入SPSS软件进行分析,最终建立推断年龄的方程模型;从研究样本外随机抽取已知年龄的样本181例进行肓测。结果牙齿钙化评分值与年龄相关分析结果相关系数r均大于0．6,同名牙评分值侧别间统计分析结果P〉0．05且相关系数r均大于0．93,方程拟合优度检验R^2=0．789,估计值标准误为1．28岁,盲测结果与真实年龄的平均误差为0．421±0．272岁。结论本研究所建立的方法在推断中国汉族女性6～18周岁群体年龄方面有良好的应用前景。     

分子生物学方法推断年龄的研究进展

<正>根据骨骼和牙齿的形态学改变，通过多项观察指标的联合评价，能较准确地推断年龄。但对于软组织或斑痕检材，如皮肤、血痕、精斑等，就无法用形态学观察推断年龄。近年来，用化学、分子生物学方法或技术推断年龄研究，已成为法医学和人类学领域新的热点。本文作者根据近年来国内外一些文献资料，就其用分子生物学方法或技术推断年龄的研究进行综述，旨在为法医实践及进一步的研究提供新的方法或思路。     

The applications of MicroCT in studying age-related tooth morphological change and dental age estimation: A scoping review

Conventional dental age estimation relies on destructive methods such as sectioning and staining, which are unpreferable when the tooth is required for evidential or archeological preservation. MicroCT is a non-destructive, high-resolution imaging technique that allows for accurate morphometrical measurement. Although microCT technology has been applied in a variety of dental studies, studies focusing on dental age-related change and dental age estimation based on microCT imaging remain lacking. Based on the question: “How has microCT technology been applied in studying human age-related tooth morphological change and dental age estimation studies?”, the authors conducted a scoping review in accordance with the Arksey and O'Malley (2005) and the PRISMA-ScR guidelines. A literature search using five major scientific databases identified 452 articles, with 11 full-text articles being eligible to be included in the scoping review. Furthermore, 6 out of the 11 studies performed dental age estimation modeling. An overview of the parameters used in the selected articles revealed a variety of tooth characteristics, such as pulp cavity to whole tooth volume ratio, secondary dentin, as well as the diameter of root canal orifice. The findings of this scoping review highlight the extent microCT is used in studying dental age-related changes, as well as the effectiveness of microCT in dental age estimation studies. This review serves as a guide for future forensic odontology age estimation studies.     

年龄推断的研究现状

推断年龄目前主要依据人体骨骼、软组织、细胞和生物大分子,以及组织中各类物质的物理和化学特性等随年龄增长的时序性变化。由于生物体各组织器官生长发育的生理性变化及其影响因素极为复杂,不同推断年龄的方法均有其应用价值,但也都存在一定的局限性,在法医学实际检案中如果能综合运用,可提高年龄推断的准确性。本文回顾国内外年龄推断现状,并对各种推断方法进行讨论。     

Age Estimation by Amino Acid Racemization in Human Teeth

Abstract: When an unidentified body is found, it is essential to establish the personal identity of the body in addition to investigating the cause of death. Identification is one of the most important functions of forensic dentistry. Fingerprint, dental, and DNA analysis can be used to accurately identify a body. However, if no information is available for identification, age estimation can contribute to the resolution of a case. The authors have been using aspartic acid racemization rates in dentin (D‐aspartic acid/L ‐ aspartic acid : D/L Asp) as an index for age estimation and have obtained satisfactory results. We report five cases of age estimation using the racemization method. In all five cases, estimated ages were accurate within a range ±3 years. We conclude that the racemization method is a reliable and practical method for estimating age.     

Thermal Modifications of Root Transparency and Implications for Aging: A Pilot Study

Root transparency has proven to be related to age and has been considered by different odontological methods for age estimation. Very little is known concerning possible variations of root transparency with heat, although the applicability of the method to burnt remains depends on the possible modifications of this specific variable. This pilot study presents the results of an experiment performed on 105 teeth obtained from dental patients and autopsy material, heated in an industrial oven at 50°C, 100°C, 150°C and 200°C. Root transparency was measured before and after the charring experiment. The heating process proved to radically modify root transparency, which decreased in 20% of samples at 50°C, in 34.6% at 100°C, in 50% at 150°C, in 77% at 200°C. The overall correlation index (CI) between decrease in root transparency and increase in temperature amounted to 0.96. These results show that heat may modify root transparency and suggest caution in using methods based on root transparency for age estimation.     

A Test of Age Estimation Methods on Impacted Third Molars in Males

This study tests the relationship between third molar impaction and its concomitant effect on age estimation methods. Data were collected on radiographs of males analyzed in the Defense POW/MIA Accounting Agency Laboratory (n = 114). Radiographs of skeletonized individuals were scored for dental development, and age was assigned based on the appropriate ancestry‐based method. Differences between identified age and estimated dental age were assessed to determine whether molar impaction affected root development and age estimations. Results indicate that impacted teeth tend to be underdeveloped and result in age estimates that are too low. While these results are of note to anthropologists and odontologists performing dental age estimates, more work is needed to explore the effect of impaction on development among a more diverse sample.     

Validity Comparison of Three Dental Methods for Age Estimation Based on Tooth Root Translucency

Age estimation of nonliving subjects plays a very important role in identifying human remains. When adult remains are in question, this process becomes even more complex. Among the numerous dental methods that exist for adults aging, the evaluation of root translucency is one of the most useful. This study studies the correlation between age and root translucency by investigating monoradicular teeth affected by pathological processes using the equations proposed by Lamendin, Prince & Ubelaker and from Singhal et al. The average age values calculated according to the three methods were compared with the values of known age. Age estimation using the Student's t‐test resulted as more accurate in the methods by Singhal et al. and by Prince & Ubelaker, with respect to that of Lamendin. Age estimation based solely on the percentage of radicular dentinal translucency has been found to be more accurate when diseased teeth are involved.     

Orthodontic Treatment: Real Risk for Dental Age Estimation in Adults?

Dental age estimation becomes a challenge once the root formation is concluded. In living adults, one dental age indicator is the formation of secondary dentine, also associated with orthodontic treatment as well as root shortening. The aim of this study was to establish whether these secondary effects of orthodontic treatment could generate a statistically significant difference in dental age estimations when using Kvaal's method. The study sample included 34 pairs of pre‐ and postorthodontic panoramic radiographs, from different individuals with exactly the same age and sex distribution. Females 65%, median age 17.5 years, and males 35%, median age 22.5 years, were included. After data collection, dental age was estimated per tooth using formulae previously published. The risk of obtaining over‐estimation of age was calculated. (RR = 1.007). The changes caused by orthodontic treatment do not have any significant effect on age estimation when Kvaal et al.'s method is applied on panoramic radiographs.     

Validation of the Acetabulum As a Skeletal Indicator of Age at Death in Modern European‐Americans,

Progressive changes in the acetabulum have been used in modern skeletal age estimation, but they have not been completely understood. If their age correlations are weakened by the influence of factors like physical activity and obesity, acetabular changes should not be used for age estimation. To investigate their utility for aging, the acetabular variables of Rissech et al. (2006) were analyzed in 409 modern European‐Americans (Bass Collection, Tennessee). Correlation tests assessed potential associations between acetabular data, osteoarthritis scores (collected per Jurmain, 1990), and documented demographic information (age, body mass index [BMI], metabolic intensity of physical activities). Acetabular changes had statistically significant, positive correlations with osteoarthritis (p < 0.001 in most joints/regions) and age (p < 0.001), indicating their degenerative nature and relevance for age estimation. Acetabular changes showed no associations with BMI or metabolic values, suggesting resistance to obesity and activity effects. These results suggest that acetabular degeneration is a valid skeletal age‐at‐death indicator.     

河南省安阳市6-15周岁汉族人牙龄的研究

目的建立利用牙齿钙化程度推断未成年人年龄的方法。方法选取河南省安阳市1575名（男性900名,女性675名）6～15周岁人群的全口曲面断层影像片,依照牙齿钙化分级标准对下颌恒牙钙化程度进行评分分级;所得数据经SPSS13．0软件统计分析,建立根据牙齿钙化程度推断年龄的方程;采用拟合优度检验、模型方差分析、回归系数检验和共线性诊断、残差分析对方程的合理性进行检验及盲测。结果下颌同名牙间钙化分级评分值无统计学差异（P〉0．05）,而下颌同名牙性别间钙化评分值在部分年龄组存在差异（P〈0．05）;下颌恒牙的钙化程度与年龄相关系数r均大于0．7;所建方程模型调整决定系数均大于0．8,估计值标准误男性为0．92岁至1．04岁、女性为0．92岁至1．00岁;推测年龄与真实年龄的平均误差男性为0．433±0．288岁、女性为0．502±0．297岁。结论本研究建立的方法在推断相关地区、相关年龄段人群的年龄推断中有较好的应用前景。