Micro-CT Evaluation of Ceramic Inlays: Comparison of the Marginal and Internal Fit of Five and Three Axis CAM Systems with a Heat Press Technique.
OBJECTIVE
To evaluate the marginal and internal adaptation of CAD/CAM lithium-disilicate inlay restorations fabricated by two milling systems (Five and Three-axis), and a traditional heat-press technique.


METHODS
Fifteen premolar teeth with an MOD cavity preparation were fabricated. Lithium-disilicate inlay restorations were obtained by three fabrication techniques and fitted to their dies (n = 15/gp) as follows: Group-1, three-axis milling system, Group-2, five-axis milling system, Group-3, conventional heat-press technique. Gaps were evaluated by X-ray microtomography. Marginal gap (MG), occlusal-marginal gap (OMG), proximal-marginal gap (PMG), gingival-marginal gap (GMG), absolute marginal discrepancy (AMD), axial-internal gap (AIG), and occlusal-internal gap (OIG) were evaluated at 120 different points per inlay. Data were analyzed using repeated measures ANOVA. Pairwise comparisons were conducted for post-hoc testes and the Bonferroni correction was used to adjust for multiple comparisons (α = 0.007).


RESULTS
The heat-press group demonstrated significantly smaller mean-values amongst all outcomes compared with CAD/CAM groups except for GMG, where there was no statistically significant difference between groups in the ANOVA (p = 0.042). Within the CAD/CAM groups, the five-axis group showed significantly lower OMG mean-value compared with the three-axis group p < 0.001, and lower AIG mean-value compared with the three-axis group p < 0.001. There was no significant difference between the five-axis and the three-axis groups' AMD, MG, PMG, and OIG locations.


CONCLUSIONS
Different fabrication techniques affected the marginal and internal adaptation of ceramic inlay restorations. The heat-press group showed the best marginal and internal adaptation results; however, in every group, all samples were within the clinically acceptable MG limit (100 μm).


CONCLUSIONS
The marginal fit and internal adaptation of inlay ceramic restorations fabricated by a five-axis milling system have not been tested or compared with those fabricated by three-axis machines and the conventional heat-press method. The preferred method of inlay fabrication, whether in the lab or chair side, may be influenced by the results of this study and could affect future clinical decision-making. (J Esthet Restor Dent 29:49-58, 2017).
Clinical Specialist, Department of Restorative Dentistry, National Guard Hospital, Riyadh, Saudi Arabia.
Norah K
NK
Alajaji
Clinical Professor, Prosthodontics and Operative Dentistry, Tufts University School of Dental Medicine, Boston, MA, USA.
David
D
Bardwell
Associate Professor, Department of Public Health and Community Service, Tufts University School of Dental Medicine, Boston, MA, USA.
Matthew
M
Finkelman
Assistant Professor, Department of Prosthodontics Tufts University School of Dental Medicine, OneKneeland Street, Office 224, Boston, MA, 0211, USA.
Ala
A
Ali
D002516:Ceramics; D017076:Computer-Aided Design; D006358:Hot Temperature; D007284:Inlays; D055114:X-Ray Microtomography / Q000379:methods*