Longitudinal analysis of deciduous tooth emergence: III. Sexual dimorphism in Bangladeshi, Guatemalan, Japanese, and Javanese children

Are deciduous upper molars and lower canines useful for sex estimation?

OBJECTIVE

This paper investigates whether deciduous upper molars and lower canines have sexual dimorphic features, exploring these teeth' dimensions and the presence of Zuckerkandl's tubercle and Carabelli's cusp on the first and second upper molars.

DESIGN

We analyzed 64 pairs of dental plaster casts from 34 females and 30 males aged between 3 and 12 years. We measured the first and second deciduous upper molars and the lower deciduous canines (maximum mesiodistal and buccolingual length), and we registered the presence of the Zuckerkandl's tubercle and the Carabelli's cusp on the first and second upper molars, respectively.

RESULTS

Regarding the differentiation between sexes using Carabelli's cusp and Zuckerkandl's tubercle, the classification was not independent of Carabelli's cusp presence only for tooth 65 (p = 0.035). In all other teeth, whether for Carabelli's cusp or Zuckerkandl's tubercle, their presence was similar for both sexes. There were statistically significant differences between sexes (p < 0.05) for the buccolingual measurements of both upper second molars, the first right upper molar, and the right canine. The developed model allowed for a 64.1% accuracy in sex estimation.

CONCLUSIONS

The study suggests that while Carabelli's cusp and Zuckerkandl's tubercle in upper deciduous molars don't consistently differ between sexes, tooth size, particularly the buccolingual measurements of certain teeth, including upper deciduous molars and lower canines, may provide a more reliable criterion for sex estimation. The developed model depicted moderate accuracy, underscoring the need for a multifactorial approach when estimating sex from skeletal remains. It suggests that while dental features can contribute to sex estimation, they should be used in conjunction with other skeletal or molecular markers to improve accuracy.

Global variations in eruption chronology of primary teeth: A systematic review and meta-analysis

OBJECTIVES

This systematic review aimed to assess global variations in the eruption chronology of primary teeth in children and the role of sexes, jaws, and socio-economic status on eruption timing.

DESIGN

An extensive search of electronic databases, grey literature, and hand-searching was carried out until April 2023 RESULTS: A total of 42,109 children, with an age range of 0-83 months were included from 42 studies (22 in Asia, 7 in Europe, 5 in Africa, 4 in North America, 3 in Oceania and 1 in South America). The mandibular central incisor was the first tooth to erupt at 6 months in North America and 13.5 months in Asia while the mandibular second molar erupted at 20.1 months in Europe and 29 months in South America.

CONCLUSIONS

The age of primary teeth eruption was advanced in the European population followed by North America, Africa, Oceania, and Asia while it was delayed in the South American population. Meta-analysis showed that tooth eruption was earlier in the left quadrant than the right but the role of other factors (sexes, jaws, and socio-economic status) was insignificant. Population-specific data on primary teeth emergence may serve as a baseline for future research. In clinical practice, these population-based eruption charts can serve as a valuable asset for diagnosis and treatment planning in children.

Path Analysis of the Relationships between the Eruption Time of the First Primary Teeth and Various Factors in Twins

The timing of primary tooth eruption is critical for children's health planning and the diagnosis of specific growth disorders. The purpose of this study is to assess the relationship between twin pairs' birth weight, gestational age, and gender, which are indicators of prenatal factors; breast-feeding duration, which is an indicator of postnatal factors; type of delivery, which is an indicator of maternal as well as genetic factors; and age of the primary tooth. Twin children aged from 3 to 15 years who applied to the clinic for the first dental examination constituted the sample group. In this twin study, 59 monozygotic (MZ) twin pairs and 143 dizygotic (DZ) twin pairs were included. Genetic (MZ vs. DZ), maternal (type of delivery, gestational age), perinatal (birth weight, gender), and postnatal (duration of breastfeeding) information was obtained, and effects on the children's Eruption Timing of the First Primary Tooth (ETFPT) were examined. Statistical analysis was performed using the consistent partial least squares structural equation model (robust PLSc) technique. As birth weight increased, the age at first eruption became younger, but this change was different between MZ and DZ twins (p < 0.05). While the age at first tooth eruption was older in identical twins who were breastfed for the first 6 months, this increase was not observed in DZ twins. The mean of ETFPT was calculated as 7.31 months in MZ twins and 6.75 months in DZ twins. The effect of breastfeeding and birth weight on ETFPT may differ according to zygosity in twins. MZ twins may tend to take longer to experience the eruption of their first primary teeth.

Eruption Timing and Sequence of Primary Teeth in a Sample of Romanian Children

Teething is considered a significant event in the growth and development of the child by parents and especially by paediatric dentists and forensic scientists. They constantly need an “up-to-date mirror” of its variability for different geographic regions. The aims of the current study were to determine the timing and sequence of primary tooth emergence, and to establish a correlation between tooth eruption and general growth and external parameters in a sample of Romanian children. This study included 70 healthy children (53% girls and 47% boys), and the analysed data resulted from the questionnaires completed by parents during the whole process. General and specific data on primary teeth eruption were obtained. The differences between sexes were insignificant, except for the maxillary and mandibular canines (p = 0.047 and p = 0.018) and lower temporary second molars (p < 0.001), which were significantly increased in boys. The differences found between the two hemiarches were insignificant (p = 0.197). The mean age of eruption of the first tooth erupted was 7.07 ± 1.990 months. The unpaired t-test was used for comparison of the timings of eruption of the first primary teeth, according to the number of previous births and type of diet, and it was insignificant (p = 0.665 and p = 0.983 respectively).

Wich factors influencing the number of teeth at 12 months of age: a birth cohort study

This study aimed to verify, through a longitudinal follow-up, the pre-, peri- and postnatal factors associated with the eruption of deciduous teeth. The study was nested in a Birth Cohort Study conducted in Pelotas, a Southern Brazilian city. Mothers were followed prenatally and their children were followed-up perinatally, at 3 and 12 months of age. The outcome was the number of teeth at 12 months, and exploratory variables included maternal habits and characteristics, anthropometric measures of children and mothers, and socioeconomic and demographic information. Data were collected through interviews with the mother and children's clinical exam. Poisson regression models were used for the analysis. Participants included 4,014 children with a mean number of erupted teeth at 12 months of 5.50. After adjustments, a lower mean number of teeth was observed in children from non-white mothers, early preterm children, and shorter children at birth and at 12 months. A higher number of teeth was observed for mothers with excessive weight gain during pregnancy, mothers who smoked during pregnancy, weightier children at birth and at 12 months, and for children with larger heads at birth and at 12 months. Our findings suggest that maternal and children characteristics influenced primary tooth eruption.

Associations of maternal, perinatal and postnatal factors with the eruption timing of the first primary tooth

We recruited 1296 mothers in their first trimester from the Affiliated Obstetrics and Gynecology Hospital of Nanjing Medical University between May 2014 and September 2015 to investigate the associations of maternal, perinatal and postnatal factors with the eruption timing of the first primary tooth (ETFPT) in a Chinese population. We collected maternal demographic information and clinical data during the perinatal and postnatal period, and oral examinations of the infants were performed by a doctor at 6, 9 and 12 months of age. Multiple regression analysis was used to identify significant explanatory variables for ETFPT. The mean age at eruption of the first primary tooth for all the infants was 6.82 ± 1.90 months. After adjustment for confounders, higher maternal childbearing age (β = 0.57; 95%CI = 0.13–1.02), female sex (β = 0.26; 95%CI = 0.07–0.52), and low birth weight (β = 0.98; 95%CI = 0.20–1.76) were significantly associated with delayed eruption of the first primary tooth, while macrosomia (β = −0.79; 95%CI = −1.30–−0.28) was significantly associated with earlier eruption of the first primary tooth. Maternal childbearing age, infant sex and infant birth weight were significant determinants of ETFPT.

Sexual dimorphism of primary dentition in Spanish children

AIM

To analyse differences in the eruption of primary teeth between both sexes.

MATERIALS AND METHODS

A cross-sectional study was performed in a sample of 1250 children aged between 3 and 42 months. The clinical emergence of teeth was taken to estimate average ages for primary teeth eruption. The t-test was used to analyse gender and arch differences.

RESULTS

Eruption of primary teeth began at the same time in girls as in boys; although the eruptive process was longer in girls. It was observed that almost all deciduous teeth emerged earlier in boys, except for the first molar (upper and lower) and the maxillary central incisors. The differences were statistically significant for almost all the primary teeth except for the central incisors, both upper and lower.

CONCLUSIONS

By comparing the timing of the eruption of primary teeth in both sexes, it was found that eruption of almost all primary teeth took place earlier in boys than in girls and that the eruption process was shorter for boys than for girls. Most of the deciduous teeth erupted earlier in the right side in both sexes. No differences were found in the sequence of eruption of primary teeth between genders.

Impact of birth characteristics, breast feeding and vital statistics on the eruption of primary teeth among healthy infants in Saudi Arabia: an observational study

OBJECTIVES

This study aimed to explore the impact of gender, birth weight, maternal age, type of delivery, gestational age and feeding practices on the eruption of teeth in children with no underlying medical conditions or developmental defects in their first year of life.

DESIGN

A cross-sectional observational study design was used.

SETTING

A primary healthcare setting in Riyadh, Saudi Arabia.

PARTICIPANTS

All children in their first year of life attending a vaccination clinic (n=422) were included in the study. Infants with chronic childhood illnesses, those who were below the 5th percentile in height or weight, infants with congenital birth defects and chronic illnesses, infants who were born preterm and low birth weight infants were excluded from the study.

OUTCOME MEASURES

The type of delivery, birth weight, age of mother, height and weight percentile for age (as plotted on the WHO growth chart for infants) and feeding practices were recorded by the examiner, and this was followed by a clinical examination to determine the presence or absence of each tooth. Regression models were developed to determine the effect of the different variables on the presence of primary teeth.

RESULTS

There was a significant association between the weight percentile of the child (adjusted for age) and the number of erupted primary teeth, suggesting that heavier children have an earlier eruption of teeth. No association was observed between birth weight, height percentile for age or maternal age at the time of birth and the number of erupted primary teeth. Children who were exclusively breast fed were significantly more likely to have an erupted first primary tooth earlier than non-breastfed group.

CONCLUSIONS

Breast feeding and the weight of the child may have an influence on the eruption of primary teeth in the first year of life.

Estimation of age from development and eruption of teeth

The developing dentition is used to assess maturity and estimate the age in many disciplines including anthropology, archeology, forensic science, pediatric dentistry and orthodontics. There is evidence that dental development is less effected than skeletal development by malnutrition and hormonal disorders. There are two methods of dental age assessment, radiographically and by clinically visualization of eruption of teeth. The clinical method to assess dental age is based on the emergence of teeth in the mouth. This method is more suitable since it does not require any special equipment, expertise and is more economical. Tooth formation is the best choice for estimating the age as variations are less as compared to other development factors. Eruption of teeth is one of the changes observed easily among the various dynamic changes that occur from the formation of teeth to the final shedding of teeth. The times of eruption of teeth are fairly constant and this can be made use of in ascertaining the average age of eruption of the tooth. Assessment of age of an individual by examination of teeth is one of the accepted methods of age determination.

Estimation of age from development and eruption of teeth

The developing dentition is used to assess maturity and estimate the age in many disciplines including anthropology, archeology, forensic science, pediatric dentistry and orthodontics. There is evidence that dental development is less effected than skeletal development by malnutrition and hormonal disorders. There are two methods of dental age assessment, radiographically and by clinically visualization of eruption of teeth. The clinical method to assess dental age is based on the emergence of teeth in the mouth. This method is more suitable since it does not require any special equipment, expertise and is more economical. Tooth formation is the best choice for estimating the age as variations are less as compared to other development factors. Eruption of teeth is one of the changes observed easily among the various dynamic changes that occur from the formation of teeth to the final shedding of teeth. The times of eruption of teeth are fairly constant and this can be made use of in ascertaining the average age of eruption of the tooth. Assessment of age of an individual by examination of teeth is one of the accepted methods of age determination.

Estimating the distribution of probable age-at-death from dental remains of immature human fossils

In two historic longitudinal growth studies, Moorrees et al. (Am J Phys Anthropol 21 (1963) 99-108; J Dent Res 42 (1963) 1490-1502) presented the "mean attainment age" for stages of tooth development for 10 permanent tooth types and three deciduous tooth types. These findings were presented graphically to assess the rate of tooth formation in living children and to age immature skeletal remains. Despite being widely cited, these graphical data are difficult to implement because there are no accompanying numerical values for the parameters underlying the growth data. This analysis generates numerical parameters from the data reported by Moorrees et al. by digitizing 358 points from these tooth formation graphs using DataThief III, version 1.5. Following the original methods, the digitized points for each age transition were conception-corrected and converted to the logarithmic scale to determine a median attainment age for each dental formation stage. These values are subsequently used to estimate age-at-death distributions for immature individuals using a single tooth or multiple teeth, including estimates for 41 immature early modern humans and 25 immature Neandertals. Within-tooth variance is calculated for each age estimate based on a single tooth, and a between-tooth component of variance is calculated for age estimates based on two or more teeth to account for the increase in precision that comes from using additional teeth. Finally, we calculate the relative probability of observing a particular dental formation sequence given known-age reference information and demonstrate its value in estimating age for immature fossil specimens.

Relationship between socio-demographic and anthropometric variables and number of erupted primary teeth in suburban Nigerian children

The socio-demographic and anthropometric variables could influence the number of teeth present in the child's mouth. To determine the effect of anthropometric and socio-demographic variables on the number of erupted primary teeth, a cross-sectional study was performed involving 1013 children aged between 4 and 36 months who attended the immunization clinics in Ile-Ife, Nigeria. Statistical analyses were performed using STATA. The analyses included frequencies, cross-tabulations, chi squared test and t-test. The number of erupted teeth was modelled as the dependent variable in a multiple regression (Binomial) model, and the socio-demographic (age, gender and socio-economic status) and anthropometric variables, such as weight and height at presentation, as predictor variables. Statistical significance was inferred at P < 0.05. The age and height at presentation had significant association with the number of erupted teeth in this study population (P < 0.001). Also children from high socio-economic class in relation to low socio-economic class had significant larger number of erupted teeth in this study population (P < 0.001). The age and height of the child at presentation were significantly related to the number of erupted teeth. Also children from high socio-economic class had significant lager number of erupted teeth compared with children from low socio-economic class.

Longitudinal analysis of deciduous tooth emergence: IV. Covariate effects in Japanese children

Emergence of the deciduous teeth is generally considered to be robust to moderate environmental insults, malnutrition, and disease. Consequently, deciduous tooth emergence has been used to assess growth and development and for age estimation in children. In this paper, we examine the way in which nutritional status and other covariates affect deciduous tooth emergence in a sample of 114 Japanese children born in Tokyo in 1914 and 1924. Parametric survival analysis was used to quantify the effects of nutritional status, breastfeeding behavior, and sex on the hazard of deciduous tooth emergence. Children of poor nutritional status exhibited significantly delayed emergence of all deciduous teeth, with effects that ranged from 14-29% increases in mean emergence times. Children of medium nutritional status exhibited increases in mean emergence times of 5-9% for the canines and lower molars, and 13-17% for the incisors. Partial breastfeeding had no effect on tooth emergence, but children who were not breastfed at all showed delayed emergence of the upper incisors. No significant sex differences in emergence were found. The findings contradict the idea that moderate malnutrition has little effect on deciduous tooth emergence. Furthermore, nutritional differences may account for some of the observed differences among populations in the timing of tooth emergence.