The study of oro-dental structures and application of dental adhesives in patients affected with osteogenesis imperfecta

Abstract

Objectives: To investigate genetic mutations, oro-dental features, tooth ultrastructures, and characteristics of total-etch adhesives (Optibond FL; Kerr) and self-etch adhesives (Clearfill SE Bond; Kuraray) applied on the teeth of the patients who affected with syndromic osteogenesis imperfecta and dentiongenesis imperfecta(DGI), compared with the controls. Methods: Three patients were diagnosed with osteogenesis imperfecta and dentinogenesis imperfecta at Faculty of Medicine, Chulalongkorn University. Clinical, radiographic, and laboratory examination were performed. Genetic mutations were analyzed by whole-exome sequencing (WES) and Sanger sequencing. Three teeth were obtained, one tooth from each patient (DGI tooth). Each tooth sample was examined for its color by colorimeter, mineral composition by Micro-CT scan, surface roughness by profilometer, microhardness by Knoop microhardness tester, microscopic morphology by scanning electron microscope (SEM) and histology, and mineral composition by EDX. The microtensile and microshear bond strengths (µTBS and µSBS) of two dental adhesive system, total-etch adhesives (Optibond FL; Kerr) and self-etch adhesives (Clearfill SE Bond; Kuraray), were analyzed compared with the controls. Results: WES identified that the patients with OI and DGI harbored the missense mutations in COL1A2. The DGI teeth were yellowish and dark. The size of dentin and pulp cavity and enamel surface roughness of DGI teeth were diverse. Mineral density of DGI enamel was lower than that of the controls while the mineral density of DGI dentin was variable. Knoop microhardness values of DGI dentin were statistically lower than those of the controls. Correspondingly, DGI enamel also showed reduced microhardness values. Carbon percentage was increased in both DGI enamel and dentin. SEM revealed irregular arrangement and reduced number of dentinal tubules in DGI teeth. Dental adhesive analyses showed that µTBS and µSBS of DGI teeth were lower than those of the controls. Optibond FL showed superior µTBS and µSBS with DGI dentin compared to Clearfil SE bond. Conclusions: This study demonstrates that syndromic DGI teeth of OI patients possessing the missense mutations in COL1A2 exhibited alterations in clinical characteristic, dentin ultrastructure, mineral density, and hardness of dental tissues. These variations could influence the performance of dental adhesives.