Care Index, Treatment Needs, and Bilateral Occurrence of Dental Caries in the First Permanent Molars of Mexican Schoolchildren.

Background Dental caries is a chronic, multifactorial, and preventable disease caused by cariogenic bacteria, fermentable carbohydrates, host factors (saliva and tooth structure), and time. In Mexico, it is a public health problem, exacerbated by the lack of access to dental care. The first permanent molar (FPM), key to occlusion and mastication, is vulnerable to bilateral caries, suggesting systemic or environmental influences. Studying its bilateral pattern would help optimize preventive strategies, especially in marginalized populations with limited resources. This study aimed to determine the prevalence of caries and bilateral occurrence in the FPMs of a sample of Mexican schoolchildren, as well as to describe the Care Index and treatment needs. Methods A cross-sectional study was conducted. A total of 428 FPMs from 107 children (5-12 years) treated at a pediatric dental clinic of a public university in Mexico, which provides specialized services at low cost to the general population, were evaluated. The decayed, missing, and filled teeth index, the Care Index, and the Treatment Needs Index (TNI) were recorded. Symmetry tests (Stuart-Maxwell) were used to analyze bilaterality. Data were processed with Stata 14.0 (StataCorp LP, College Station, TX, USA). Results Of the total, 50.5% were boys, and the average age was 8.52±1.36. A total of 58.9% of children presented caries (overall decayed, missing, and filled teeth index: 1.90±2.01; in FPMs: 1.71±1.74), and 57.0% presented at least one affected FPM. It was observed that 43.0% had no caries experience in their four FPMs, and 28.0% had caries experience in all FPMs. The Care Index was 42.7%, and the TNI was 67.4%. The percentage of bilaterality was 84.1% for upper molars and 81.3% for lower molars. There were no significant differences in caries bilaterality between upper (p=0.1969) and lower (p=0.3896) molars, suggesting symmetry in the involvement. Conclusions Bilaterality was observed in the caries experience of the lower molars in this sample. Approximately one in four children had caries in their four FPMs. The high prevalence of caries and treatment needs underscores the urgency of affordable, preventative interventions, especially in vulnerable populations.