Demirjian法测定成都地区8-16岁青少年牙龄

目的评估Demirjian法测定成都地区青少年牙龄的准确度并对其进行修正。方法应用Demirjian法测定445名成都地区8～16岁汉族青少年牙齿成熟指数及牙龄,比较测得牙龄与实际年龄的差异;将牙齿成熟指数与实际年龄进行曲线拟合,建立两者问的数学模型。结果Demirjian法测得牙龄比实际年龄平均高估：其差异为女性0．67岁,男性0．52岁,其差异有统计学意义;牙齿成熟指数与实际年龄呈指数关系;根据修正后方程所得牙龄与实际年龄平均差异为女性0．15岁,男性-0．08岁,其差异无统计学意义。结论Demirjian法不能直接用于测定成都地区青少年牙龄,应用时需对其进行修正。     

应用Demirjian法测定北京地区6～16岁儿童的牙龄

目的评估Demirjian法测定北京地区儿童牙龄的准确度并对其进行修正。方法应用Demirjian法测定276名北京地区儿童(男131名,女145名)的牙齿成熟指数和牙龄,比较牙龄和实际年龄的差异;将牙齿成熟指数和年龄进行曲线拟合,建立两者间的数学模型。结果Demirjian法测定的牙龄比实际年龄平均高估了0.31a(女性)、0.26a(男性),差异有显著性;牙齿成熟指数(y)与年龄(x)成指数关系。结论修正后的Demirjian法更适合于测定北京地区儿童的牙龄。     

两种方法推断上海地区青少年牙龄的比较研究

目的 分别运用Demirjian法和Willems法推断上海地区青少年的牙龄,评估两种方法的适用性及准确性。方法 选取上海交通大学医学院附属第九人民医院影像科符合纳入标准的11~18岁青少年口腔曲面断层片共1122例,其中男性444例,女性678例;分别使用Demirjian法和Willems法评估左下颌7颗恒牙的总成熟度后得到牙龄,对实际年龄与推断的牙龄之间进行配对t检验或Wilcoxon秩和检验;通过比较两种方法的平均绝对误差（Mean Absolute Error, MAE）,对两种方法的准确度进行评估。结果 Demirjian法推断的牙龄与实际年龄相比,男性低估0.35岁、女性低估0.27岁。而用Willems法推断时,牙龄比实际年龄分别低估0.64岁（男性）和0.67岁（女性）。统计学结果显示,两种方法推断的牙龄与实际年龄之间均有显著差异（P<0.05））。对比Demirjian法和Willems法的MAE, Demirjian法的MAE为1.23岁; Willems法的MAE为1.27岁。结论 相较于Willems法, Demirjian法的准确度和适用性较高。两种方法均不适用于直接推断上海地区青少年的牙龄,应用时需要对其进行修正。     

三种牙龄推断法在乌鲁木齐儿童及青少年中的应用

目的 研究Demirjian、Willems和Cameriere法三种方法推断乌鲁木齐市汉族和维吾尔族儿童及青少年年龄的适用性。方法 对纳入的693张全口曲面断层片（其中汉族306张，维吾尔族387张）进行判读，利用SPSS26.0软件对测得的牙龄与生理年龄进行统计学分析，并对两个民族差异进行分析。结果 Demirjian法对汉族男性和女性分别高估0.37岁、0.50岁，对维吾尔族男性和女性分别高估0.30岁、0.46岁；Willems法对汉族男性和女性分别低估0.02岁、0.09岁，对维吾尔族男性和女性分别低估0.07岁、0.05岁；Cameriere法对汉族男性和女性分别低估0.26岁、0.42岁，对维吾尔族男性和女性分别低估0.16岁、0.29岁。结论 Willems法在推断乌鲁木齐市汉族和维吾尔族儿童及青少年年龄时最准确，两个民族用相同牙龄方法推测年龄时无显著差异。     

三种方法在南京地区儿童牙龄评估中的准确性

目的：：研究Demirjian、Willems、Haavikko三种方法评估南京地区儿童自然年龄的适用性和准确性。方法：本研究共纳入符合要求的南京市儿童全口曲面断层片450张(男性263张,女性187张),按照三种牙龄分期方法对左下颌7颗恒牙进行判读,查表得出牙龄,将所得牙龄与自然年龄进行配对t检验。结果：在评估南京地区儿童牙龄时Demirjian法平均高估0.50岁(男0.48岁、女0.53岁);Willems法平均高估0.02岁(男0.09岁、女-0.07岁);Haavikko法平均低估0.85岁(男0.87岁、女0.82岁);Haavikko第一磨牙法平均低估0.42岁(男性0.45岁、女性0.36岁);Haavikko中切牙法平均低估0.65岁(男0.66岁,女0.61岁)。结论：Willems法在评估南京地区儿童年龄时最为准确,其次为Demirjian法,Haavikko法准确性较差;应用Haavikko法单个牙齿进行牙龄评估时,第一磨牙、中切牙最为准确,并且其准确性高于原始Haavikko法。     

成都地区青少年第三磨牙牙龄与年龄的相关性研究

目的 对成都地区青少年第三磨牙牙龄与年龄的相关性进行研究。方法 选择2009-2011年于四川大学华西口腔医院正畸科就诊的青少年患者,拍摄全景片,参照Demirjian法的牙龄判断标准对左下颌第三磨牙发育情况进行分期。对不同性别第三磨牙的发育程度进行成组设计t检验分析,对第三磨牙发育程度与生理年龄的关系进行Spearman相关分析。结果 在Demirjian分期为A期时,不同性别第三磨牙的发育程度有统计学差异（P=0.026）,男性发育早于女性。Spearman相关分析表明：男性、女性及总体样本的生理年龄与第三磨牙发育程度均有相关性（男性r=0.808,P=0.000;女性r=0.729,P=0.000;总体r=0.760,P=0.000）。年龄（X）和第三磨牙发育程度（Y）的相关回归方程为：Y总体=4.898+2.036X;Y男性=4.987+2.046X;Y女性=4.819+2.036X。结论 第三磨牙发育程度可以作为推断青少年生理年龄的一个可靠指标。     

Demirjian法在推断南京地区儿童自然年龄中的应用

目的：研究Demirjian法（下文简称＂D法＂）推断南京地区儿童自然年龄的适用性。方法：收集南京医科大学附属口腔医院符合纳入标准的年龄在3～16岁患者的全口曲面断层片共644例,其中男性378例,女性266例。按照D法进行牙龄推断,所得牙龄与自然年龄进行配对t检验,通过建立单因素数学模型探索两者之间的对应关系。结果：直接运用D法对南京地区儿童进行牙龄推断,所得出的结果与实际年龄相比,差异有统计学意义（P〈0.01）。建立南京地区儿童牙齿成熟度与自然年龄间的数学模型,得到自然年龄与牙总成熟度的拟合曲线方程：男子组为Y=43.37SIN（0.02579X-1.138）＋30.6SIN（0.04275X＋0.9984）＋3.019SIN（0.08706X＋1.649）,女子组为Y=55.93SIN（0.04001X-1.642）＋90.97SIN（0.05389X＋0.7095）＋44.25SIN（0.06254X＋3.384）。将其推断的年龄与实际自然年龄比较,两者间的差异无统计学意义（P〉0.05）。结论：本研究通过建立儿童牙齿成熟度与自然年龄间的数学模型,可以利用牙齿发育程度较为准确推断南京地区3～16岁儿童的自然年龄。     

重量法测量121 例正常[牙合]错[牙合]咀嚼效能的研究

目的：比较正常[牙合]不同年龄、性别的咀嚼效能;正常[牙合]与错[牙合]不同年龄、性别咀嚼效能的差异.方法：重量法分别测算出121 例11～16 岁及21～25 岁正常[牙合]与错[牙合]咀嚼值.121 例中48 例正常[牙合],73例包括上颌前突、前牙反[牙合]、拥挤在内的错[牙合].用SPSS 10.0统计软件的独立样本t检验（2 样本资料的均数比较,即成组t检验）对有关组分别进行比较.结果：21～25 岁男女正常[牙合]平均咀嚼值之间,男性咀嚼值远远高于女性的咀嚼值,P=0.000,有高度显著性差异;不同年龄咀嚼值的差异在男性表现明显：21～25 岁男性正常[牙合]的平均咀嚼值明显高于11～16 岁男性正常[牙合]的平均咀嚼值,P〈0.01,差异有高度显著性;11～16 岁男性中前牙反[牙合]的平均咀嚼值低于正常[牙合]的平均咀嚼值,P〈0.05,差异有显著性;21～25 岁女性中上颌前突的平均咀嚼值比正常[牙合]的平均咀嚼高,P〈0.05, 有显著性差异;21～25 岁女性中前牙拥挤的平均咀嚼值比正常[牙合]的平均咀嚼值高,P〈0.05, 有显著性差异.结论：青年男性咀嚼效能远远高于女性的咀嚼效能; 青年男性正常[牙合]咀嚼效能明显高于青少年男性正常[牙合]的咀嚼效能; 青少年男性前牙反[牙合]的咀嚼效能低于青少年男性正常[牙合]的咀嚼效能;青年女性中上颌前突和拥挤的咀嚼效能高于正常[牙合]的咀嚼效能.     

新疆哈萨克族青少年正常

目的建立新疆哈萨克族青少年正常(牙合)牙冠宽及牙量分析指数数据库.方法选取新疆地区100名正常(牙合)哈萨克族青少年,制取牙颌模型并测量,对所测数据进行性别间比较,与西安汉族青少年相应数据进行比较.结果建立了正常(牙合)哈萨克族青少年牙冠宽及牙量分析指数的均值及标准差;哈萨克青少年牙冠宽度性别间比较具有统计学差异,男性大于女性;与西安汉族青少年比较,牙弓宽度、牙量等各项数值,两民族比较均具有统计学差异,哈萨克族的各项数值均大于西安汉族数值.结论本研究结果进一步证明了不同种族、民族、地区的牙齿、牙弓大小及形态存在着差异.     

新疆哈萨克族青少年正常(牙合)模型测量研究

目的:建立新疆哈萨克族青少年正常(牙合)牙冠宽及牙量分析指数数据库.方法:选取新疆地区100名正常(牙合)哈萨克族青少年,制取牙颌模型并测量,对所测数据进行性别间比较,与西安汉族青少年相应数据进行比较.结果:建立了正常(牙合)哈萨克族青少年牙冠宽及牙量分析指数的均值及标准差;哈萨克青少年牙冠宽度性别间比较具有统计学差异,男性大于女性;与西安汉族青少年比较,牙弓宽度、牙量等各项数值,两民族比较均具有统计学差异,哈萨克族的各项数值均大于西安汉族数值.结论:本研究结果进一步证明了不同种族、民族、地区的牙齿、牙弓大小及形态存在着差异.     

Dental age table for a sample of Pakistani children

The aim of this study was to evaluate the applicability of Demirjian's dental age assessment table in a sample of Southern Pakistani population and, if not applicable, to formulate a separate dental age table for Pakistani males and females. The study was conducted on the dental pantomographs of a sample size of 882 subjects (427 males and 455 females) ranging in age from 7 to 14 years. A paired t-test was used to assess any difference between chronological age and dental age assessed according to Demirjian's method. Logit function was used to make the relationship between dental maturity and chronological age and linear regression analysis with the equation X = [Ln {y/100 - y} - a]/b was used to generate dental age tables for Pakistani males and females. Dental age assessed according to Demirjian's method for this male sample was over-predicted in the 7 year and 11-15 year age group (P < 0.05). In the female sample, there was an over-prediction in all the age groups (P < 0.05). Statistically significant differences were found in chronological and dental age assessed by Demirjian's method for Pakistani males and females and thus, a new table was generated to convert dental maturity calculated according to Demirjian's method into dental age for the population.     

Assessment of dental maturity of Brazilian children aged 6 to 14 years using Demirjian's method

Summary. Dental maturity, often expressed as dental age, is an indicator of the biological maturity of growing children. A method for the assessment of dental maturity was first described by Demirjian, and is widely used and accepted, mainly because of its ability to compare different ethnic groups. This is possible, as the maturity scoring system proposed by the method is universal in application, although the conversion to dental age depends on the population considered.
Objectives. The aim of this study was to apply Demirjian's method to Brazilian children aged 6–14 years in order to obtain dental maturity curves for each sex, to compare this data with that obtained by Demirjian, and to determine whether there is a significant correlation between dental maturity and body mass index.
Methods. We retrospectively reviewed the orthopantomograms, height and weight measurements of 689 healthy children. Curves of dental maturity of males and females were constructed.
Results. When compared to the French-Canadian sample of Demirjian, Brazilian males and females were 0·681 years and 0·616 years, respectively, more advanced in dental maturity. There was no significant correlation between dental maturity and body mass index.     

成都地区儿童和青少年牙龄与颈椎骨龄的相关性分析

目的探讨成都市儿童和青少年颈椎骨龄与牙龄之间的关系,为正畸治疗评价患者骨骼和牙齿发育情况提供依据。方法通过数码曲面断层片和头颅定位侧位片对成都市256例10～16岁儿童和青少年的颈椎骨龄和牙龄进行测量,运用统计学分析方法探讨颈椎骨龄、年龄和牙龄之间的关系。结果通过Spearman相关性分析,颈椎骨龄与年龄之间呈高度相关（r=0.726,P＜0.01）,牙龄与年龄之间呈中度相关（r=0.629,P＜0.01）,牙龄与颈椎骨龄也呈中度相关（r=0.668,P＜0.01）。结论成都市儿童和青少年颈椎骨龄、年龄和牙龄之间均有相关性,其中颈椎骨龄与年龄呈高度相关性。正畸治疗中判断患者的生长发育情况时,采用颈椎骨龄进行评价优于牙龄。     

Dental maturity in children of short stature, with or without growth hormone deficiency

The aim of this investigation was to study dental maturity in healthy prepubertal children of short stature (height < −2 SD), with or without growth hormone (GH) deficiency, compared to healthy controls. The GH-deficient group (GH level < 10.0 μg/l) included 29 children (11 female. 18 male) with a mean age of 10.2 ± 2.2 years. The GH non-deficient group consisted of 17 children (5 female. 12 male) with a mean age of 8.5 ± 2.1 years. All the children were evaluated for serum concentrations of IGF-1, alkaline phosphatase (ALP), triiodthyronin (T3), thyroxine (T4). thyroid-stimulating hormone (TSH). and fasting plasma insulin: height and bone age were also recorded. Dental maturity was determined from panoramic radiographs. The mean difference between the dental and chronological ages was −0.67 ± 0.89 years in the GH-deficient group compared to 0.23 ± 1.07 years in their controls: in the GH non-deficient group the difference was −0.95 ± 0.82 years compared to controls 0.16 ± 1.06 years in their controls. Compared to chronological age. both bone and dental age were lower in the GH-deficient and GH non-deficient groups. It is concluded that children of short stature, both GH-deficient and GH non-deficient, exhibit a delayed dental age compared to their chronological age- and sex-matched controls. A multiple stepwise regression analysts showed that the sitting height and GH level were the only significant factors associated with dental maturity.     

Assessment of dental maturity of children aged 3.5 to 13.5 years using the Demirjian method in an Iranian population

Radiographs of developing teeth are commonly used to assess dental maturity. The method for assessment of dental maturity first described by Demirjian is widely used and accepted. The aim of this study was to assess the accuracy of the Demirjian method in an Iranian population in order to compare the difference in dental maturity between these children with the data obtained in Canadian children and to determine whether there is a correlation between dental maturity and BMI-for-age. In this study, the orthopantomographs of 519 healthy children (264 boys and 255 girls) aged 3.5-13.5 years were reviewed and the dental age was determined by the Demirjian method. The chronological ages of the children were obtained by subtracting their birthdates from the date of taking the radiograph. Height and weight measurements were also recorded and the data were analyzed using SPSS-16 software. The Demirjian method overestimated the age by 0.15 and 0.21 years in boys and girls, respectively. Paired t-test analysis showed that these differences were statistically significant (P = 0.001). The increase in mean age difference initiated from the underweight group towards the overweight group, but this correlation was not statistically significant (P = 0.094). Based on the amount of differences between estimated dental age and chronological age in this investigation, the Demirjian method seems to be clinically applicable in the Iranian population.     

Dental maturation in short and long facial types. Is there a difference?

OBJECTIVE: The purpose of this investigation was to study the relationship between vertical skeletal growth pattern and dental maturation in children with long or short anterior facial height. MATERIALS AND METHODS: The sample consisted of the records of 312 Dutch children (153 boys and 159 girls, aged 9-12.9 years, with a mean chronological age of 11.3 years). The subjects were selected according to their lower anterior facial height as a percentage of the total facial height. Two groups, one with long and the other with short anterior facial height, were formed for further comparison. Dental age, according to Demirjian's dental maturity score, was determined for each subject. The power of the study was 79% (2-sided test) and 87% (1-sided test). RESULTS: There was no statistically significant difference in dental age score between the two extreme groups. The subjects with short anterior facial height demonstrated a slight tendency toward more advanced dental age. CONCLUSIONS: The difference in dental age between long and short facial types is not big enough to be clinically relevant.     

Advanced dental maturity in children with juvenile rheumatoid arthritis

The subjects of the investigation comprised 95 girls and 73 boys with juvenile rheumatoid arthritis (JRA), and 102 girls and 66 boys representing healthy controls, all with a chronological age from 6.3 to 14.4 yr. The dental development was assessed from panoramic radiographs using a seven-tooth model. The radiographs were evaluated on three separate occasions with a minimum interval of one month in a randomized order, and blind with respect to absence or presence of JRA. In both JRA patients and healthy controls, dental maturity was ahead of chronological age. In addition, dental maturity was significantly advanced in JRA patients with 0.26 yr in girls and 0.28 yr in boys. It is tentatively suggested that the advanced dental development in JRA patients compared with healthy children was partly an effect of treatment with cortisone, while the influence of the disorder per se remains to be elucidated.