This study aimed to investigate the prevalence and associated factors of malocclusion among children with primary dentition in Xi’an, China. A total of 2,974 subjects were selected from local schools in Xi’an city using a stratified cluster sampling method from January to September 2015. After screening samples according to the inclusion criteria, the final sample size comprised 2,235 pre-school children, with a mean age of 4.82 (SD, 1.76; range, 2.63–6.12) years. Malocclusion traits were assessed by trained clinicians followed by the evaluation of associated factors through clinical examination and a precisely designed questionnaire including data regarding gender, birth place, parental education level, monthly familial income, parental attitude toward the problem of malocclusion, feeding methods of the children, feeding postures, pacifier use, and delivery methods. Data were analyzed using the Chi-square test and logistic regression analysis. The most common type of malocclusion was increased overjet (34.99 %) in the sagittal direction, deep overbite (37.58 %), and midline deviation (25.32 %) in the vertical and transverse directions, respectively. The prevalence of posterior crossbite, anterior crossbite, and anterior open bite was 7.56, 6.80 and 6.98 %, respectively. The prevalence of the anterior edge-to-edge occlusion was the lowest (2.46 %). The variables associated with malocclusion (P < 0.05) were birth place (odds ratio [OR] = 1.741 with 95 % CI of 1.384–2.162), insufficient abrasion of primary canines (OR = 1.465; 95 % CI of 1.153–1.894), caries in primary teeth (OR = 2.045; 95 % CI of 1.665–2.539), tongue thrusting (OR = 2.833; 95 % CI of 1.640–3.649), mandibular prognathism (OR = 2.621; 95 % CI of 1.574–3.689), and finger sucking (OR = 1.573 with 95 % CI of 1.098–2.014). The feeding methods (OR = 3.614 with 95 % CI of 3.087–4.596) along with the method of delivery (OR = 1.847 with 95 % CI of 1.323–2.451) have been observed to play an important role in the morbidity of malocclusion (P < 0.05). The prevalence of malocclusion among pre-school children in Xi’an is higher compared to that in other geographical parts of China. Therefore, early attention to the development of occlusion and necessary interventions toward the associated factors are important to reduce its prevalence and further adverse effects.

Wei He, Yanqin Zhang, Yi Qu, Mengmeng Liu, Guodong Li, Luxiang Pan, Xinyao Xu, Gege Shi, Qiang Hao, Fen Liu & Yuan Gao. BMB Reports 2024;57:71-8. https://doi.org/10.5483/BMBRep.2023-0160

Background: Caesarean-section (C-section) may influence children’s long-term health by affecting bacterial colonization. However, few studies have focused on the association between C-section delivery (CSD) and dental caries, and previous conclusions have been conflicting. This study aimed to explore whether CSD would increase the risk of early childhood caries (ECC) in preschool children in China. Methods: This study was a retrospective cohort study. Three-year-old children with full primary dentition were included through the medical records system. Children in the nonexposure group were vaginally delivered (VD), while children in the exposure group were delivered through C-section. The outcome was the occurrence of ECC. After agreeing to participate in this study, guardians of included children completed a structured questionnaire on maternal sociodemographic factors, children’s oral hygiene and feeding habits. The chi-square test was used to determine differences in the prevalence and severity of ECC between the CSD and VD groups and to analyse the prevalence of ECC according to sample characteristics. Subsequently, potential risk factors for ECC were preliminarily identified through univariate analysis, and the adjusted odds ratios (ORs) were further calculated through multiple logistic regression analysis after controlling for confounding factors. Results: The VD group included 2115 participants while CSD group included 2996 participants. The prevalence of ECC was higher in CSD children than in VD children (27.6% vs. 20.9%, P < 0.05), and the severity of ECC in CSD children was higher (mean number of decayed, missing, and filled teeth, dmft: 2.1 vs. 1.7, P < 0.05). CSD was a risk factor for ECC in 3-year-old children (OR = 1.43, 95% CI = 1.10–2.83). In addition, irregular tooth brushing and always prechewing children’s food were risk factors for ECC (P < 0.05). Low maternal educational attainment (high school or below) or socioeconomic status (SES-5) may also increase the prevalence of ECC in preschool children and CSD children (P < 0.05). Conclusions: CSD would increase the risk of ECC in 3-year-old Chinese children. Paediatric dentists should devote more attention to the development of caries in CSD children. Obstetricians should also prevent excessive and unnecessary CSD.