IADR Abstract Archives
Evaluation of CAD/CAM Restorations by Optical Coherence Tomography
Objectives: Swept-source optical coherence tomography (SS-OCT) has shown potential for in-depth imaging and monitoring of tooth and composite restorations. Sound enamel is almost transparent in the near infrared region, therefore this wavelength range has been increasingly adopted for dental imaging. The aim of this study was to investigate the potential of SS-OCT at 1300 nm center wavelength for evaluation of the CAD/CAM ceramic restorations. The null hypothesis was that there was no difference in light attenuation characteristics of these ceramic substrates compared to human tooth enamel.
Methods: An intraoral scan (Trios, DentaSwiss by 3Shape) of a typodont molar onlay preparation was used to digitally design a ceramic onlay and mill restorations (n=5) from 3 types of CAD/CAM blocks in appropriate milling machine: E4D (Planmeca)- leucite glass-ceramic (EMP: EmpressCAD, IvoclarVivadent); DentaSwiss DS1300 (Biodenta)- lithium disilicate glass-ceramic (EMX: e.maxCAD, IvoclarVivadent) and DentaSwiss DS2000 (Biodenta) - PS zirconia (ZRC: LavaPlus, 3M ESPE). After sintering, the restorations were fitted on the prepared tooth model and scanned by SS-OCT (OCT 2000, Santec). Cross-sectional images were obtained from the facial and palatal aspects of the onlay. An SS-OCT attenuation coefficient based on Beer–Lambert law was calculated on each scan for each group, and compared to values obtained from human sound enamel on 10 extracted teeth (Enamel).
Results: Mean ±standard deviation values of attenuation coefficients in each group were 0.58 ±0.02, 0.29 ±0.06, 0.62 ±0.05 and 0.55 ±0.12 mm-1 for EMP, EMX, ZRC and Enamel, respectively. One-way ANOVA with Bonferroni correction showed that there was a difference in attenuation coefficient between EMX and other groups (p<0.05), while there was no statistical difference among EMP, ZRC and Enamel (p>0.05).
Conclusions: Structural integrity and marginal adaptation of the CAD/CAM restorations (figure) can be effectively evaluated by SS-OCT, as the attenuation coefficient of near infrared laser through these materials was equal or lower than that of enamel.
Methods: An intraoral scan (Trios, DentaSwiss by 3Shape) of a typodont molar onlay preparation was used to digitally design a ceramic onlay and mill restorations (n=5) from 3 types of CAD/CAM blocks in appropriate milling machine: E4D (Planmeca)- leucite glass-ceramic (EMP: EmpressCAD, IvoclarVivadent); DentaSwiss DS1300 (Biodenta)- lithium disilicate glass-ceramic (EMX: e.maxCAD, IvoclarVivadent) and DentaSwiss DS2000 (Biodenta) - PS zirconia (ZRC: LavaPlus, 3M ESPE). After sintering, the restorations were fitted on the prepared tooth model and scanned by SS-OCT (OCT 2000, Santec). Cross-sectional images were obtained from the facial and palatal aspects of the onlay. An SS-OCT attenuation coefficient based on Beer–Lambert law was calculated on each scan for each group, and compared to values obtained from human sound enamel on 10 extracted teeth (Enamel).
Results: Mean ±standard deviation values of attenuation coefficients in each group were 0.58 ±0.02, 0.29 ±0.06, 0.62 ±0.05 and 0.55 ±0.12 mm-1 for EMP, EMX, ZRC and Enamel, respectively. One-way ANOVA with Bonferroni correction showed that there was a difference in attenuation coefficient between EMX and other groups (p<0.05), while there was no statistical difference among EMP, ZRC and Enamel (p>0.05).
Conclusions: Structural integrity and marginal adaptation of the CAD/CAM restorations (figure) can be effectively evaluated by SS-OCT, as the attenuation coefficient of near infrared laser through these materials was equal or lower than that of enamel.
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