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[Effects of the resin base and retention depth on fracture resistance of molars restored with nano-ceramic endocrowns].
Beijing Da Xue Xue Bao Yi Xue Ban. 2022 Feb 18; 54(1):95-99.BD

Abstract

OBJECTIVE

To compare the effects of resin base and different retention depth on the fracture resistance of mandibular molars restored with nano-ceramic endocrowns.

METHODS

Forty mandibular molars selected and randomly divided into 5 groups: ① The control group which was consisted of intact teeth, ② the non-resin base group, ③ the 2 mm retention depth group, ④ the 3 mm retention depth group, ⑤ the 4 mm retention depth group, respectively. After tooth preparation, in vitro root canal therapy was conducted, which was followed by endocrown design, production and adhesive of groups ②-⑤. All the samples were under load (N) of the universal mechanical testing machine after embedding. The fracture pattern of each sample was observed under stereomicroscope. Then the microstructure of the fracture surface was observed by scanning electron microscopy.

RESULTS

The fracture loads of each group were respectively: the control group fracture load was (3 069.34±939.50) N; experimental groups: fracture load of (2 438.04±774.40) N for the group without resin base; fracture load of (3 537.18±763.65) N for the group with 2 mm retention depth. The fracture load of the retention depth 3 mm group was (2 331.55±766.39) N; the fracture load of the retention depth 4 mm group was (2 786.98±709.24) N. There was statistical significance in the effect of resin base and different retention depth on the fracture loads of molars restored with nano-ceramic endocrown (P < 0.05). Repairable fractures in each group were as follows: control group 2/8, non-resin base group 1/8, retention depth of 2 mm group 1/8, retention depth of 3 mm group 2/8, and retention depth of 4 mm group 0/8. The effects of the retention depth and the presence of resin base on the fracture resistance of the resin nano-ceramic endocrowns were statistically significant (P < 0.05). Scanning electron microscopy showed more arrest lines and small twist hackles on the fracture surface of the restorations with resin base (retention depths of 2 mm, 3 mm, and 4 mm), with cracks extending towards the root. In addition to the characteristics above, more transverse cracks parallel to the occlusal surface, pointing outwards from the center of the pulp cavity retention, were also observed on the fracture surface of the non-resin base restorations.

CONCLUSION

When molar teeth with nano-ceramic endocrowns are restored, resin base and the retention depth of 2 mm help the teeth to obtain optimal fracture strength.

Authors+Show Affiliations

Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digtal Stomatology & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China.Department of Dental Materials, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digtal Stomatology & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China.Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digtal Stomatology & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China.Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digtal Stomatology & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China.

Pub Type(s)

Journal Article

Language

chi

PubMed ID

35165474

Citation

Li, Z, et al. "[Effects of the Resin Base and Retention Depth On Fracture Resistance of Molars Restored With Nano-ceramic Endocrowns]." Beijing Da Xue Xue Bao. Yi Xue Ban = Journal of Peking University. Health Sciences, vol. 54, no. 1, 2022, pp. 95-99.
Li Z, Xu YX, Bao XD, et al. [Effects of the resin base and retention depth on fracture resistance of molars restored with nano-ceramic endocrowns]. Beijing Da Xue Xue Bao Yi Xue Ban. 2022;54(1):95-99.
Li, Z., Xu, Y. X., Bao, X. D., & Wang, X. Y. (2022). [Effects of the resin base and retention depth on fracture resistance of molars restored with nano-ceramic endocrowns]. Beijing Da Xue Xue Bao. Yi Xue Ban = Journal of Peking University. Health Sciences, 54(1), 95-99.
Li Z, et al. [Effects of the Resin Base and Retention Depth On Fracture Resistance of Molars Restored With Nano-ceramic Endocrowns]. Beijing Da Xue Xue Bao Yi Xue Ban. 2022 Feb 18;54(1):95-99. PubMed PMID: 35165474.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - [Effects of the resin base and retention depth on fracture resistance of molars restored with nano-ceramic endocrowns]. AU - Li,Z, AU - Xu,Y X, AU - Bao,X D, AU - Wang,X Y, PY - 2022/2/15/entrez PY - 2022/2/16/pubmed PY - 2022/2/17/medline KW - Endocrowns KW - Fracture resistance KW - Resin base KW - Resin nano-ceramic KW - Retention depth SP - 95 EP - 99 JF - Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences JO - Beijing Da Xue Xue Bao Yi Xue Ban VL - 54 IS - 1 N2 - OBJECTIVE: To compare the effects of resin base and different retention depth on the fracture resistance of mandibular molars restored with nano-ceramic endocrowns. METHODS: Forty mandibular molars selected and randomly divided into 5 groups: ① The control group which was consisted of intact teeth, ② the non-resin base group, ③ the 2 mm retention depth group, ④ the 3 mm retention depth group, ⑤ the 4 mm retention depth group, respectively. After tooth preparation, in vitro root canal therapy was conducted, which was followed by endocrown design, production and adhesive of groups ②-⑤. All the samples were under load (N) of the universal mechanical testing machine after embedding. The fracture pattern of each sample was observed under stereomicroscope. Then the microstructure of the fracture surface was observed by scanning electron microscopy. RESULTS: The fracture loads of each group were respectively: the control group fracture load was (3 069.34±939.50) N; experimental groups: fracture load of (2 438.04±774.40) N for the group without resin base; fracture load of (3 537.18±763.65) N for the group with 2 mm retention depth. The fracture load of the retention depth 3 mm group was (2 331.55±766.39) N; the fracture load of the retention depth 4 mm group was (2 786.98±709.24) N. There was statistical significance in the effect of resin base and different retention depth on the fracture loads of molars restored with nano-ceramic endocrown (P < 0.05). Repairable fractures in each group were as follows: control group 2/8, non-resin base group 1/8, retention depth of 2 mm group 1/8, retention depth of 3 mm group 2/8, and retention depth of 4 mm group 0/8. The effects of the retention depth and the presence of resin base on the fracture resistance of the resin nano-ceramic endocrowns were statistically significant (P < 0.05). Scanning electron microscopy showed more arrest lines and small twist hackles on the fracture surface of the restorations with resin base (retention depths of 2 mm, 3 mm, and 4 mm), with cracks extending towards the root. In addition to the characteristics above, more transverse cracks parallel to the occlusal surface, pointing outwards from the center of the pulp cavity retention, were also observed on the fracture surface of the non-resin base restorations. CONCLUSION: When molar teeth with nano-ceramic endocrowns are restored, resin base and the retention depth of 2 mm help the teeth to obtain optimal fracture strength. SN - 1671-167X UR - https://www.unboundmedicine.com/medline/citation/35165474/[Effects_of_the_resin_base_and_retention_depth_on_fracture_resistance_of_molars_restored_with_nano_ceramic_endocrowns]_ L2 - http://xuebao.bjmu.edu.cn/EN/Y2022/V54/I1/95 DB - PRIME DP - Unbound Medicine ER -