Distribution and morphology of enamel hypomineralisation defects in second primary molars.

Objective: The purpose of this study was to investigate defect distribution and morphology in hypomineralised second primary molars (HSPM), presence of similar defects in other primary teeth and clinical similarities with molar-incisor hypomineralisation (MIH).

Methods: This clinical descriptive study involved children who attended a postgraduate paediatric dental clinic in a 20-month period and were diagnosed with HSPM. The updated MIH/HSPM index of Ghanim et al. (Eur Arch Paediatr Dent 16(3):235-46, 2015) was used to record defects on primary molars and canines.

Results: 54 children (23 boys) aged 4 to 12 years comprised the study sample. The mean number of affected second primary molars per child was 2.65 with no statistically significant difference between maxilla and mandible or between right and left side with defects more frequently located on buccal surfaces. 66.7% of the children were mildly affected (opacities only) with 29 out of 54 having defects occupying less than 1/3 of the surface. Severity increased with increasing number of affected teeth and extent of the defects per child. Similar defects were recorded in the first primary molars and canines in 55.5% of the children who had those teeth present.

Conclusions: The distribution and morphology pattern of HSPM defects was similar to that in MIH, supporting the notion of a common hypomineralisation entity.