No abstract

DESCRIPTIONA healthy Caucasian girl aged 12 years was referred to the dental clinic by a general dentist who failed to completely instrument canals in the mesial and distal root of tooth 36 (FDI system). In the first session, supernumerary root radix entomolaris (RE) was identified and cone beam CT (CBCT) scan was taken. Afterwards, several ledges in the root canals were successfully negotiated and treatment was completed in the third session (figure 1). CBCT revealed the presence of RE also on tooth 37 and Figure 1 Postoperative radiograph of the left first permanent mandibular molar exposed with mesial horizontal angulation. The tooth was obturated by cold lateral condensation technique using precurved stainless steel spreaders, precurved gutta-percha cones and AH Plus sealer (Dentsply DeTrey).

All children, who were born in 2004 and had undergone surgical treatment for recurrent acute tonsillitis and/or acute otitis media at the ear, nose and throat clinic (ENT) between 2004 and 2010, were called on dental examination and blood sampling. Out of 441 invitees, 113 children and their parents/legal guardians agreed to participate. The following data from this group of subjects are presented: the presence of clinical signs of molar–incisor hypomineralisation (MIH), the distribution of human leukocyte antigen (HLA) alleles DQ2 and DQ8 and eight single nucleotide polymorphisms (SNPs) located in amelogenesis-related genes (rs3796704 in the ENAM gene, rs546778141 in the AMBN gene, rs2106416 in the AMELX gene, rs7660807 and rs35286445 in the AMTN gene, rs4870723 in the COL14A1 gene, rs2245803 in the MMP20 gene, and rs3828054 in the TUFT1 gene). Data on clinical signs of MIH were collected in accordance with the recommendation and on the proposed MIH clinical data recording sheet [1] , and with appropriate preliminary training and calibration. Data on HLA DQ2 and DQ8 haplotypes and on SNPs of amelogenesis-related genes were obtained using DNA isolated from blood samples taken from subjects. The HLA DQ2 and DQ8 alleles were determined using the EliGene® Coeliac RT Kits (90,048-RT; Elisabeth Pharmacon spol. s.r.o., Brno-Židenice, Czech Republic) on a 7500 Fast RT-PCR System (Applied Biosystems, Waltham, MA, USA). The distributions of SNPs in the amelogenesis-related genes were determined using high resolution melting (HRM) using the Type-IT HRM Master Mix (Qiagen), TaqMan genotyping assays (ID: C__25766207_10; Thermo Fisher Scientific, Waltham, MA, USA) with the TaqMan Universal Master Mix II, or Sanger sequencing using sequencing master mix BigDye® Terminator v3.1 (Applied Biosystems) and ABI 3500 Genetic Analyser (Applied Biosystems). L. Hočevar, J. Kovač, K. Trebušak Podkrajšek, S. Battelino, A. Pavlič, 2020. The possible influence of genetic aetiological factors on molar–incisor hypomineralisation, Arch. Oral. Biol. 118, 104848. https://doi.org/10.1016/j.archoralbio.2020.104848 .

Introduction. Molar-incisor hypomineralisation (MIH) is a developmental defect of dental enamel that affects one to all four first permanent molars (FPM) and frequently permanent incisors. Enamel aberrations are observed as demarcated opacities of different colours (from white to brown) and as posteruptive enamel breakdown (PEB). Clinically similar pathological signs can also be present in deciduous molars. Case outline. Histology of an FPM and a second deciduous molar (SDM) was performed after extraction from two unrelated patients with MIH due to inflammatory complications. Tooth samples were analysed using a stereomicroscope (SM), light microscope (LM) and scanning electron microscope (SEM). Enamel thickness of both affected teeth was normal. An obvious distinction in enamel microstructure was observed between the normally developed and the MIH-hypomineralised enamel with SM, LM, and SEM. Conclusion. In MIH patients, regular dental visits enable early diagnosis of the disease and appropriate treatment of the patient as soon as possible, with included preventive measures.