Prevalence of molar incisor hypomineralization (MIH) in Singaporean children.

BACKGROUND: There is a lack of data on molar incisor hypomineralization (MIH) in Asia, but this is not an indication that MIH is rare in the Asian population. Early identification of MIH is important as affected teeth frequently display post-eruptive enamel loss which would result in rapid caries progression. AIM: This objective of this study was to assess the prevalence of MIH in Singaporean children. DESIGN: Patients were recruited from 30 schools across Singapore. All children were examined by a single dentist, and the judgement criteria used were based on the 2003 European Academy of Paediatric Dentistry criteria. RESULTS: A total of 1083 children; average age of 7.7 ± 0.3 years were examined. One hundred and thirty-five children (12.5%) had MIH. A significantly higher proportion of children of the Malay ethnicity had MIH, compared to Chinese children (P = 0.02). Post-eruptive enamel breakdown and the presence of atypical restorations were correlated with increasing number of MIH teeth/child (Rho= 0.599, P < 0.001) and the cumulative enamel opacity colour score (Rho = 0.601, P < 0.001). CONCLUSIONS: Our findings suggest the role of ethnicity in MIH occurrence and that MIH severity may be influenced by the number of MIH teeth/child and the cumulative enamel opacity colour score.

Polish retention of new aesthetic restorative materials over time.

New aesthetic restorative materials claiming superior polish retention have recently been introduced. This study compared polish retention of eight different types of aesthetic restorative materials including ormocer and nanofill composites over a 6-month ageing period in distilled water. Eight specimens of each material were fabricated and roughened with 320 grit grinding paper using a lapping device and finished/polished with a graded abrasive disk system. Mean roughness was then determined using a surface profilometer. The specimens were then stored in distilled water at 37 degrees C and roughness measurements were repeated after 3 and 6 months of ageing. Mean surface roughness values ranged from 0.15 to 0.68 microm for immediate readings and 0.17 to 1.02 microm after ageing for 6 months. With the exception of the highly viscous glass ionomer cement, the surface polish of most materials did not deteriorate much over time. At all time intervals, composite materials based on ormocer and nanomer technology were significantly smoother than all other materials evaluated.