Analysis of dental abfractions by optical coherence tomography

摘要

Aim and objectives. Abfraction is the pathological loss of cervical hard tooth substance caused by biomechanicalrnoverload. High horizontal occlusal forces result in large stress concentrations in the cervical region of the teeth. Thesernstresses may be high enough to cause microfractures in the dental hard tissues, eventually resulting in the loss of cervicalrnenamel and dentin. The present study proposes the microstructural characterization of these cervical lesions by en facernoptical coherence tomography (eFOCT).rnMaterial and methods: 31 extracted bicuspids were investigated using eFOCT. 24 teeth derived from patients withrnactive bruxism and occlusal interferences; they presented deep buccal abfractions and variable degrees of occlusalrnpathological attrition. The other 7 bicuspids were not exposed to occlusal overload and had a normal morphology of therndental crowns.rnThe dental samples were investigated using an eFOCT system operating at 1300 nm (B-scan at 1 Hz and C-scan mode atrn2 Hz). The system has a lateral resolution better than 5 um and a depth resolution of 9 um in tissue. OCT images werernfurther compared with micro - computer tomography images.rnResults. The eFOCT investigation of bicuspids with a normal morphology revealed a homogeneous structure of thernbuccal cervical enamel. The C-scan and B-scan images obtained from the occlusal overloaded bicuspids visualized thernwedge-shaped loss of cervical enamel and damage in the microstructure of the underlaying dentin. The high occlusalrnforces produced a characteristic pattern of large cracks, which reached the tooth surface.rnConclusions: eFOCT is a promising imaging method for dental abfractions and it may offer some insight on thernetiological mechanism of these noncarious cervical lesions.