Digital Comparison of Occlusal Vertical Contacts Between Direct Composite and Indirect Cad/Cam Restorations: An in vivo quantitative assessment

Objective: Clinical assessment of the static occlusal vertical contacts for direct composite and indirect Cad/Cam restorations, and evaluation of the clinical experience level's effect on contact registration. Methods: Sixty restorations on maxillary and mandibular molar teeth were investigated. Postgraduate students performed indirect Cad/ Cam restorations (Cerasmart, GC Corp., n=20), and both undergraduate and postgraduate students performed direct composite restorations (Ganeial A'chord, GC Corp., n=20 for each). A single supervisor digitally analyzed the occlusal vertical contacts immediately after by using an intraoral scanner (iTero Element-5D, AlignTech) and OrthoCAD software. The tightness of contacts was assessed by counting the pixel numbers in Photoshop CC (Adobe) software. The statistical analyses were performed by Shapiro-Wilk, One-way ANOVA, Tamhane's T2 test, Results: No significant differences were found for the contacts closer than the yellow code (<0.4mm) among the operator/restoration types (>=.05). Whereas, significant differences were found between the undergraduate direct and postgraduate indirect restorations for the yellow contacts and the lighter ones (p<.05). Additionally, no significant contact differences were found either between the direct restorations of undergraduate and postgraduate students or between the direct and indirect restorations of postgraduate students (p >=.05 for both). Considering red, orange, and yellow code contact types together, no significant differences were observed among the operator and restoration types (p=.069). Conclusion: The restoration type was not effective in registering the occlusal vertical contacts for clinicians with equal clinical experience levels. Clinical experience was also not effective in occlusal contacts of direct restorations. Whereas, when the advantages of indirect Cad/ Cam restorations are combined with the clinical experience, tighter occlusal vertical contacts might be registered. The potential effects of additional parameters such as the restorative material and the dental technician on the occlusal vertical contacts should be investigated.