Comparison of color changes, fracture strengths, and failure modes of conventional endocrowns and endocrowns with different design modifications

Article type: Research Article

Authors: Al Ahmari, Nasser M.^{a; 1; *} | Alshehri, Abdulkarim H.^{b; 1} | Gadah, Thrya S.^{a; 1} | Alqahtani, Jaber A.^c | Almushafi, Mohammed A.^d | Al Moaleem, Mohammed M.^{b; 1} | Al Hatlan, Ebtisam N.^e | Alqhatani, Aliya S.^e | Alabydi, Shahad M.^e

Affiliations: [a] College of Dentistry, King Khalid University, Abha, Saudi Arabia | [b] Department of Prosthetic Dental Science, College of Dentistry, Jazan University, Jazan, Saudi Arabia | [c] Aseer Specialized Dental Center, Ministry of Health, Abha, Saudi Arabia | [d] General Practitioner, Ministry of Health, Abha, Saudi Arabia | [e] General Practitioner, Private Practice, Abha, Saudi Arabia

Correspondence: [*] Correspondence: Nasser M. Al Ahmari, Prosthetic Department, College of Dentistry, King Khalid University, Abha 62529, Saudi Arabia. E-mail: [email protected].

Note: [1] These authors contributed equally to this study and should be considered co-first authors.

Abstract: BACKGROUND: Endocrowns (ECs) are alternatives for rebuilding severely damaged teeth and show superior efficacy in molars over premolars. OBJECTIVE: The objective of this in vitro study is to evaluate the effects of different preparation designs with short pulp chambers on the mean color change (Δ⁢E), fracture resistance, and failure types of mandibular molar ECs. METHOD: A total of 40 extracted mandibular molars were treated endodontically and divided into four groups. Samples in groups 1, 2, 3, and 4 had occlusal preparation depths of 5 mm, 3 mm, 3 mm with ferrule, and 3 mm with boxes, respectively. The samples were immersed in coffee and their Δ⁢E values were measured by using the Commission Internationale de l’Eclairage color system. They were also subjected to a fracture test. Next, all specimens were examined visually under a stereomicroscope to evaluate their failure modes and identify their fracture origins. Data were entered and analyzed by using Statistical Package for Social Sciences. RESULTS: Among all groups, group 4 (3 mm + boxes) presented the highest Δ⁢E (4.15) after immersion in coffee. Moreover, ANOVA revealed that the Δ⁢E of group 4 (occlusal preparation depth of 3 mm with boxes) was significantly different (p< 0.05) from that of group 2 (3 mm + ferrule, 3.07). The EC with a 3 mm chamfer and ferrule showed the highest maximum load of 2847.68 ± 693.27 N, whereas that with a 5 mm chamfer finish line had a marginally reduced load at fracture of 2831.52 ± 881.83 N. The EC with a 3 mm chamber and boxes had a slightly increased maximum load of 2700.75 ± 436.40 N, whereas that with the 3 mm chamber had the lowest maximum load at fracture of 2385.97 ± 465.61 N. One-way ANOVA showed that different EC preparation designs had no effect on maximum fracture load (F [3,16] = 0.550, p= 0.6). CONCLUSION: The recorded Δ⁢E values of ECs in all groups were equal or marginally higher than the acceptable values. The EC with a 3 mm chamfer and ferrule displayed the highest mean maximum load. The EC with a 5 mm chamfer finish line had a marginally lower maximum load at fracture than other ECs. Failures, such as ceramic fracture, split fracture, and ceramic and tooth splitting above the cemento–enamel junction (CEJ) or vertically were predominant in samples with occlusal preparation depths of 3 mm with ferrule and 5 mm.

Keywords: Endocrown, color measurement, fracture strength, failure type, endocrown design

DOI: 10.3233/THC-231175

Journal: Technology and Health Care, vol. 32, no. 4, pp. 2395-2408, 2024