Tags

Type your tag names separated by a space and hit enter

Preparation Ferrule Design Effect on Endocrown Failure Resistance.
J Prosthodont. 2019 Jan; 28(1):e237-e242.JP

Abstract

PURPOSE

To evaluate the effect of preparation ferrule inclusion with fracture resistance of mandibular molar endocrowns.

MATERIALS AND METHODS

Recently extracted mandibular third molars were randomly divided into 3 groups (n = 12) with the coronal tooth structure removed perpendicular to the root long axis approximately 2 mm above the cemento-enamel junction with a slow-speed diamond saw. The pulp chamber was exposed using a diamond bur in a high-speed handpiece with pulpal remnants removed and canals instrumented using endodontic hand instruments. The chamber floor was restored using a resin core material with a two-step, self-etch adhesive and photopolymerized with a visible light-curing unit to create a 2 mm endocrown preparation pulp chamber extension. One and two millimeter ferrule height groups were prepared using a diamond bur in a high-speed handpiece following CAD/CAM guidelines. Completed preparation surface area was determined using a digital measuring microscope. Scanned preparations were restored with lithium disilicate restorations with a self-adhesive resin luting agent. All manufacturer recommendations were followed. Specimens were stored at 37°C/98% humidity and tested to failure after 24 hours at a 45° angle to the tooth long axis using a universal testing machine. Failure load was converted to MPa using the available bonding surface area with mean data analyzed using Kruskal-Wallis/Dunn (p = 0.05).

RESULTS

Calculated failure stress found no difference in failure resistance among the three groups; however, failure load results identified that the endocrown preparations without ferrule had significantly lower fracture load resistance. Failure mode analysis identified that all preparations demonstrated a high number of catastrophic failures.

CONCLUSIONS

Under the conditions of this study, ferrule-containing endocrown preparations demonstrated significantly greater failure loads than standard endocrown restorations; however, calculated failure stress based on available surface area for adhesive bonding found no difference between the groups. Lower instances of catastrophic failure were observed with the endocrown preparations containing 1 mm of preparation ferrule design; however, regardless of the presence of ferrule, this study found that all endocrown restorations suffered a high proportion of catastrophic failures but at loads greater than reported under normal masticatory function.

Authors+Show Affiliations

AEGD-1, 2nd Dental Squadron, Barksdale Air Force Base, LA.USAF Postgraduate Dental School, Keesler Air Force Base, MS.Graduate Dental Research, USAF Postgraduate School Keesler Air Force Base, MS.Graduate Dental Research, USAF Postgraduate School Keesler Air Force Base, MS.Graduate Dental Research, USAF Postgraduate School Keesler Air Force Base, MS.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

28985446

Citation

Einhorn, Michael, et al. "Preparation Ferrule Design Effect On Endocrown Failure Resistance." Journal of Prosthodontics : Official Journal of the American College of Prosthodontists, vol. 28, no. 1, 2019, pp. e237-e242.
Einhorn M, DuVall N, Wajdowicz M, et al. Preparation Ferrule Design Effect on Endocrown Failure Resistance. J Prosthodont. 2019;28(1):e237-e242.
Einhorn, M., DuVall, N., Wajdowicz, M., Brewster, J., & Roberts, H. (2019). Preparation Ferrule Design Effect on Endocrown Failure Resistance. Journal of Prosthodontics : Official Journal of the American College of Prosthodontists, 28(1), e237-e242. https://doi.org/10.1111/jopr.12671
Einhorn M, et al. Preparation Ferrule Design Effect On Endocrown Failure Resistance. J Prosthodont. 2019;28(1):e237-e242. PubMed PMID: 28985446.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Preparation Ferrule Design Effect on Endocrown Failure Resistance. AU - Einhorn,Michael, AU - DuVall,Nicholas, AU - Wajdowicz,Michael, AU - Brewster,John, AU - Roberts,Howard, Y1 - 2017/10/06/ PY - 2017/05/18/accepted PY - 2017/10/7/pubmed PY - 2019/6/4/medline PY - 2017/10/7/entrez KW - CAD/CAM KW - endodontically treated teeth KW - failure load KW - failure stress KW - lithium disilicate KW - preparation features SP - e237 EP - e242 JF - Journal of prosthodontics : official journal of the American College of Prosthodontists JO - J Prosthodont VL - 28 IS - 1 N2 - PURPOSE: To evaluate the effect of preparation ferrule inclusion with fracture resistance of mandibular molar endocrowns. MATERIALS AND METHODS: Recently extracted mandibular third molars were randomly divided into 3 groups (n = 12) with the coronal tooth structure removed perpendicular to the root long axis approximately 2 mm above the cemento-enamel junction with a slow-speed diamond saw. The pulp chamber was exposed using a diamond bur in a high-speed handpiece with pulpal remnants removed and canals instrumented using endodontic hand instruments. The chamber floor was restored using a resin core material with a two-step, self-etch adhesive and photopolymerized with a visible light-curing unit to create a 2 mm endocrown preparation pulp chamber extension. One and two millimeter ferrule height groups were prepared using a diamond bur in a high-speed handpiece following CAD/CAM guidelines. Completed preparation surface area was determined using a digital measuring microscope. Scanned preparations were restored with lithium disilicate restorations with a self-adhesive resin luting agent. All manufacturer recommendations were followed. Specimens were stored at 37°C/98% humidity and tested to failure after 24 hours at a 45° angle to the tooth long axis using a universal testing machine. Failure load was converted to MPa using the available bonding surface area with mean data analyzed using Kruskal-Wallis/Dunn (p = 0.05). RESULTS: Calculated failure stress found no difference in failure resistance among the three groups; however, failure load results identified that the endocrown preparations without ferrule had significantly lower fracture load resistance. Failure mode analysis identified that all preparations demonstrated a high number of catastrophic failures. CONCLUSIONS: Under the conditions of this study, ferrule-containing endocrown preparations demonstrated significantly greater failure loads than standard endocrown restorations; however, calculated failure stress based on available surface area for adhesive bonding found no difference between the groups. Lower instances of catastrophic failure were observed with the endocrown preparations containing 1 mm of preparation ferrule design; however, regardless of the presence of ferrule, this study found that all endocrown restorations suffered a high proportion of catastrophic failures but at loads greater than reported under normal masticatory function. SN - 1532-849X UR - https://www.unboundmedicine.com/medline/citation/28985446/Preparation_Ferrule_Design_Effect_on_Endocrown_Failure_Resistance_ L2 - https://doi.org/10.1111/jopr.12671 DB - PRIME DP - Unbound Medicine ER -