Prevalence of Hypersensitivity in Teeth Affected by Molar-Incisor Hypomineralization (MIH)

Aim: This study aimed to investigate the prevalence of hypersensitivity in molar-incisor hypomineralization (MIH)-affected molars through a census carried out in 8-year-old schoolchildren. Methods: Examinations were conducted by a calibrated examiner, using the Nyvad criteria for caries diagnosis and a new criterion for MIH assessment. For hypersensitivity assessment, all MIH-affected molars were included. Nonaffected molars from the same child were used as controls. Air blast reaction was measured using the Visual Analogue Scale (VAS) and the Schiff Cold Air Sensitivity Scale (SCASS) scale, while tactile hypersensitivity was scored using VAS only. Statistical analysis was performed using the Kruskal-Wallis test followed by Dunn’s multiple comparisons test for quantitative data. χ2 was used for the comparison of categorical data. Results: In total, 631 children were assessed, of whom 102 had MIH-affected molars (16.1%). Of these, 51.7 and 8.7% presented enamel and dentin carious lesions, respectively. Regarding the number of teeth, 239 molars were MIH affected (59.8%), with 188 (78.7%) being classified as mild (opacities only), 20 (8.4%) as moderate (posteruptive enamel breakdown), and 31 (13%) as severe (posteruptive breakdown involving dentin/atypical restorations). Hypersensitivity was recorded in only one control molar, while the prevalence of hypersensitivity in MIH-affected molars was 34.7%, being of low intensity and more prevalent in moderate (55%) and severe cases (51.6 %) than in mild cases (29.8%, p = 0.008). An association between hypersensitivity and the presence of mild and moderate cases was observed. Although the same association was observed for severe cases, it was not considered a reliable information as 90% of the MIH-affected molars with posteruptive breakdown involving dentin were affected by carious lesions. It is known that dental caries is a confounding factor for the presence of hypersensitivity. Conclusions: Hypersensitivity was significantly higher in MIH-affected molars than in nonaffected molars, being associated with MIH teeth presenting opacities and posteruptive enamel breakdown.