IADR Abstract Archives
Characteristics of Teeth and Their Malformations Associated With Skeletal Dysplasias
Objectives: Skeletal dysplasias (SD) cause numerous skeletal and orodental anomalies; however, their orodental effects have been minimally studied. The aim of this study was to investigate the tooth characteristics of patients with SD.
Methods: Four patients diagnosed with different types of SD were enrolled. Exome sequencing was performed to identify genetic variants and obtain a definite diagnosis. Each SD patient’s tooth was compared with three tooth-type matched controls. The tooth samples were investigated for mineral density, color, surface roughness, hardness, mineral composition, and ultrastructure. The mean values were analyzed using the independent samples T-test or Mann-Whitney U test.
Results: The genetic analyses indicated that the four patients were affected with 1) acromicric dysplasia (ACMICD) with LTBP3 p.Gly673Cys variant, 2) achondroplasia (ACH) with FGFR3 p.Gly380Arg variant, 3) combined hypophosphatasia and hypochondroplasia (HPP+HCH) with ALPL (p.Ala487Val and p.Asn493Lys) and FGFR3 p.Ile538Val variants, or 4) cleidocranial dysplasia (CCD) with RUNX2 p.Arg225Trp variant. We observed significantly reduced enamel and dentin microhardness of the ACMICD-tooth, reduced enamel microhardness of the CCD-tooth, and reduced dentin hardness of the ACH-tooth, compared with those of controls. The main tooth components, phosphorus and calcium, were decreased in the CCD-tooth’s enamel and dentin. The ACMICD-tooth demonstrated significantly lower phosphorus and calcium content in enamel, compared with controls. The HPP+HCH-tooth exhibited reduced calcium levels in the enamel and dentin. Scanning electron microscopy demonstrated that all SD teeth had deep grooves around the enamel prism cores with wide interrod space and rough intertubular dentin. The histological analysis revealed that the HPP+HCH-tooth had an irregular cementum layer with a poorly defined cemento-dentinal junction.
Conclusions: This is the first comprehensive study revealing altered properties and ultrastructures of teeth associated with skeletal dysplasias. We expand the understanding of these disorders and pave the way for further investigation of the genotype-phenotype correlations and precise dental management.
Methods: Four patients diagnosed with different types of SD were enrolled. Exome sequencing was performed to identify genetic variants and obtain a definite diagnosis. Each SD patient’s tooth was compared with three tooth-type matched controls. The tooth samples were investigated for mineral density, color, surface roughness, hardness, mineral composition, and ultrastructure. The mean values were analyzed using the independent samples T-test or Mann-Whitney U test.
Results: The genetic analyses indicated that the four patients were affected with 1) acromicric dysplasia (ACMICD) with LTBP3 p.Gly673Cys variant, 2) achondroplasia (ACH) with FGFR3 p.Gly380Arg variant, 3) combined hypophosphatasia and hypochondroplasia (HPP+HCH) with ALPL (p.Ala487Val and p.Asn493Lys) and FGFR3 p.Ile538Val variants, or 4) cleidocranial dysplasia (CCD) with RUNX2 p.Arg225Trp variant. We observed significantly reduced enamel and dentin microhardness of the ACMICD-tooth, reduced enamel microhardness of the CCD-tooth, and reduced dentin hardness of the ACH-tooth, compared with those of controls. The main tooth components, phosphorus and calcium, were decreased in the CCD-tooth’s enamel and dentin. The ACMICD-tooth demonstrated significantly lower phosphorus and calcium content in enamel, compared with controls. The HPP+HCH-tooth exhibited reduced calcium levels in the enamel and dentin. Scanning electron microscopy demonstrated that all SD teeth had deep grooves around the enamel prism cores with wide interrod space and rough intertubular dentin. The histological analysis revealed that the HPP+HCH-tooth had an irregular cementum layer with a poorly defined cemento-dentinal junction.
Conclusions: This is the first comprehensive study revealing altered properties and ultrastructures of teeth associated with skeletal dysplasias. We expand the understanding of these disorders and pave the way for further investigation of the genotype-phenotype correlations and precise dental management.