Eruption of Deciduous Teeth in Children from Chennai and Correlating it with Birth Weight and Term – A Cross-Sectional Study

INTRODUCTION

Tooth emergence is a dominant landmark in the course of a child's growth; therefore, the majority of parents are concerned about the scheduled emergence of teeth. An erupted tooth is defined as a tooth with any part of its crown penetrating the gingiva and visible in the oral cavity.^[1] Many studies have found dissimilarities in the tooth eruption timeline, in addition to discrepancies between different ethnic and racial groups in tooth eruption.

Tooth emergence is yet to be explored in people from Chennai,Tamil Nadu.Particulars on the tooth eruption age of deciduous teeth applied in clinical and academic conditions in Tamil Nadu are established on an alternative population, namely Caucasians. It has been proposed in the published works that norms for tooth eruption should be procured from the population to which they apply, since details pertaining to deciduous and permanent dentition might differ.^[2] Assessment of the eruption pattern could be a worthwhile benefit in identifying the diagnosis and treatment planning amidst growing years. Dental age is a major component for the execution of caries prevention (e.g., topical fluoride administration) and age assessment in the forensic discipline and anthropology. It isessential to evaluate the age of a child using the number of erupted teeth when the date of birth is unknown.

Even thoughpermanent dentition has been broadly analyzed in various populations, research findings on primary dentition are scarce.

Scientist Minot's work on the eruption of primary teeth in 1873 could be described as investigating the timing and sequence of tooth emergence. Subsequently, Kronfeld and Schour^[3-5] evolved a primary and permanent teeth eruption chronology table. Thereafter, examinations on the primary teeth eruption chronology were carried out on different populationspertaining to precise methodologies.

The objective of the current research was to explore the eruption of primary teeth among children in Chennai, Tamil Nadu, and to evaluate the involvement of birth weight and term on the eruption pattern.

MATERIAL AND METHODS

The research was a cross-sectional dental health examination conducted from February 2023 to July 2023. The samples werefrom most ofthe primary health care centers in Chennai. Primary health care centers were arbitrarily chosen from the list, using a systematic random sampling procedure.

Children aged 3-36 months were enlisted from immunization units of primary health care centers in Chennai. In 6 months, 1700 children were assessed, of which 828 were male,and 853 were female. Furthermore, it was also decided to examine 50 cases for each birth month (3-36 months) to ensure that the mean eruption time for each individual tooth would be calculated based on a fairly favorable number of samples.

Permission to conduct the study was acquired from the concerned departments. Ethical approval was obtainedfrom the Institutional Ethical Committee. Infants whose parents volunteered to participate in the study were sequentially incorporated, subsequent to describing the nature of the study to alleviate any concerns and signing a written informed consent form. A team of two pediatric dentists and two assistants visited each primary health care center on the allocated day and time.

Sociodemographic information (personal data including child name, date of birth, and age in months, home address, and phone number) was recorded from parents. Sex, birth weight, and term were obtained from the child's birth records and also checked with the parents. The inclusion criteria were: (i) Children with good health, (ii) Age of children from 3-36 months, (iii) Both sexes enrolled, (iv) Normal, very low birth weight, and low birth weight children, (v) Normal and pre-term children, and (vi) Children were from Chennai (>3 generations living in Chennai).The exclusion criteria were: (i) Parents refuse to participate, (ii) Systemic disease or any congenital deformity that could affect tooth emergence, and (iii) Children for whom precise birth dates could not be procured.

A birth weight of more than 2500 g was considered normal, 1500 g to 2500 g was considered low, and a weight less than 1500 g was considered very low, according to Tudehope and coworkers.^[6]

Towards gestational age at birth, there existed two groups: low (less than 37 weeks) and normal (at least37 weeks).^[7]

Oral examination was performed visually to determine the count of the type of erupted teeth using a dental mirror under good illumination. A tooth was consideredto be erupted when any portion of its crown had pierced the gingiva and was noticeable in the oral cavity.

The principal investigator performed the dental examination in a room adjacent to the vaccination room. The dental examination was performed first, after which vaccination was administered.

The intraoral examination was conducted with the infant positioned onthe mother's lap and inspected utilizing the knee-to-knee posture. The erupted teeth were identified and counted in each quadrant. The collected data and oral examination findings were registered in a patient’s information form. Dental chartings were put together, corresponding to the Federation Dentaire Internationale standards.

As a result of most of the eruption studies, there is no propensity for systemic disturbances in the eruption periods of analogous teeth on the two sections of the identical arch, so the particulars for the two sections were combined.

All intraoral evaluations were done by one examiner.

The data gathering was accomplished by a single trained and calibrated investigator to evade interexaminer variability.

Data wereinitially collected and presented using an Excel spreadsheet. SPSS software version 25 was used to analyze the data. Data normality was found to be non-normal using the Kolmogorov-Smirnov test. Descriptive statistics were indicated using mean, standard deviation, frequency, and percentage. The Kruskal-Wallis test was utilized for intergroup comparison between birth weight and eruption, between the month of eruption and teeth eruption, and the chi-square test for comparison between the term of birth and eruption.

RESULTS

The relationship between birth weight and the eruption of teeth is noteworthy for almost all teeth, excluding the maxillary lateral incisors, maxillary first molars, and mandibular central incisors. A significant association was observed with birth weight for the maxillary central incisor (p = 0.0038). Notably, most of them had their teeth erupted, with both 51 and 61. In contrast, no noteworthy relationship was established between birth weight and the maxillary lateral incisors. For the maxillary canine, a noteworthy relationship with birth weight was evident (p = 0.002). The majority of canines had not erupted (n = 930). There was no noteworthy relationship between birth weight and the maxillary first molars. Maxillary second molars demonstrated a noteworthy relationship with birth weight (p = 0.003), with the majority not having erupted (n = 1220), followed by two erupted teeth, 53 and 63, among 430 children [Table 1].

In favor of the mandibular central incisor, no noteworthy association with birth weight was observed. However, a significant association was found for the mandibular lateral incisors (p = 0.010), with the majority showing erupted teeth.

For the mandibular canine, a noteworthy relationship with birth weight was also evident (p = 0.003), with most canines not having erupted (n = 818), followed by both canines erupting at positions 73 and 83. Regarding the mandibular first molars, a noteworthy relationship with birth weight was found (p= 0.034), with the majority having erupted both molars at positions 74 and 84. Lastly, for the mandibular second molars, a noteworthy relationship with birth weight was noted (p= 0.006), with the majority not having erupted (n = 1120) [Table 2].

The association between normal and pre-term pregnancy with the eruption of teeth is significant for all teeth. A significant association was observed with normal and pre-term pregnancy for the maxillary central incisor (p=0.001). Notably, most of them had their teeth erupted, with both 51 and 61. On the contrary, no significant association was found between normal and pre-term pregnancy and the maxillary lateral incisors. For the maxillary canine, a significant association with normal and pre-term pregnancy was evident (p=0.001). The majority of canines had not erupted (n = 779). Significant association was found between normal and pre-term pregnancy with the maxillary first molars (p=0.015). In the case of the maxillary second molars, a significant association was noted with normal and pre-term pregnancy (p=0.001), with the majority having both erupted molars (n

For the mandibular central incisor, a significant association with normal and pre-term pregnancy was observed (p=0.003). Also, a significant association was found for the mandibular lateral incisors (p = 0.000), with the majority showing both laterals erupted (n = 1085). For the mandibular canine, a significant association with normal and pre-term pregnancy was also evident (p = 0.035), with most canines not having erupted (n = 695), followed by both canines’eruption. Regarding the mandibular first molars, a significant association with normal and pre-term pregnancy was found (p = 0.014), with the majority having erupted both molars at positions 74 and 84. Lastly, for the mandibular second molars, a significant association with normal and pre-term pregnancy was noted (p = 0.015), with the majority not having erupted (n = 957) [Table 4].

DISCUSSION

Literature reveals data availability on the eruption of teeth and the chronological age of development in permanent dentition.^[8] Data on primary dentition is scarce, and area-specific data for Chennai is also missing. To improve a proper treatment plan according to their eruption time, area-specific data on the eruption of primary teeth and their relationship with birth weight and term have been presented here.

In the Hispanic and white groups' primary dentition study, Hispanics had an advanced eruption pattern (by a month), with earlier eruption for male children.^[9] In this study, a significant 1-2 month delay in eruption was noticed compared to the literature. Central incisor in maxilla erupts at an average age of 9.4 months, whereas in this population, it takes 10-13 months for the eruption of the central incisor in the maxilla. The same pattern follows for all teeth. This variation in primary dentition eruption data might be due to the scarce availability of data on deciduous dentition. Considering the birth weight parameter for eruption, it is more contradictory in literature. According to Shourie^[10] in 2017, no significant association was found between these two parameters. However, Shalaby et al^[11] in 2023 disagreed with the above statement and found a negative association betweenbirth weight and time of eruption. That is consistent with this study, where a notable negative relation between birth weight and eruption time is evident. In almost every tooth eruption, the number of teeth erupted is reducedwhen birth weight is reduced.

According to Neto and Falcao^[12], underweight children had three times more chance of getting delayed tooth eruption, and female childrenhad four times more chance of delayed tooth eruption.

Data on the term of birth and its association with the eruption of teeth arenegligible. The available literature indicates a negative association between them.^[13,14] This cross-sectional study also confirms the above statement, showing significant variation in eruption timing in pre- and full-term birth children.

A key cause of delayed oral growth and development highlights that premature birth is a significant global issue, exerting a heavy emotional, physical, and financial toll on families and healthcare systems. Preterm birth is associated with enamel defects and contributes to delays in oral growth and development.^[15]

A study titled “Effect of Neonatal Factors on the Eruption of Primary Teeth in Children: A Longitudinal Prospective Cohort Study,” conducted in Mysuru, aimed to assess how neonatal components influence the eruption of primary teeth in infants born preterm. The study involved 105 subjects, of whom 53 were term children and 52 were pre-term children. A statistically significant dissimilarity was observed in the mean age of eruption of the mandibular central incisor between term and preterm subjects.^[16]

However, this study design is cross-sectional, where the primary concern is memory recall bias. The studiesinclude healthy children, but also pre- and full-term birth children. Nutrition-based classification for eruption cannot be associated. However, this inclusion is to avoid confounding of nutritional factors, which could affect the aim of this study. When being conducted for a larger population with a proper sampling design, the results can be generalized. Further longitudinal studies with the inclusion of parental factors affecting the eruption time can be done in this study area for the generation of more data.

CONCLUSION

With this limitation, strength, and recommendation, it can be concluded that the term of birth and birth weight were significantly and negatively associated with the eruption of teeth in primary dentition. This study puts forward that a notable 2-3 months delay inthe eruption of almost all primary dentition compared withthe standard chronology is seen in Chennai. Being an important milestone of a child’s development, the tooth eruption pattern should be reviewed and collected from various regions to educate the parents about the same.

Preterm children and those with very low birth weight tend to experience slightly delayed eruption of primary teeth. By advancing the understanding of the relationships between primary teeth eruption, birth weight, and term, oral health outcomes can be improved, and children can be provided with better oral health care.