Finite element analysis to study the effects of using CAD/CAM glass-fiber post system in a severely damaged anterior tooth

Abstract

Abstract.To investigate the stress distribution of a severely damaged maxillary anterior tooth restored with a computer-aided design/computer-aided manufacturing (CAD/CAM) glass-fiber post system. Twelve models were fabricated with different alveolar bone levels and cervical dentin wall thicknesses and studied using a two-dimensional finite element method. A force of 100 N was applied to the lingual surface of the crown at 45 degrees, and the maximum von Mises stress was calculated. A higher stress level was observed in the dentin than in the post and crown. With the reduction of dentin thickness, the maximum von Mises stress in the dentin increased slightly to a peak at a thickness of 1.5 mm, followed by a slight decrease at a thickness of 1.0 mm. However, the relative ratio (RR) values did not show a large difference (RR > 80%). Meanwhile, a large difference in RR values was observed with a change in bone level (RR < 80%). When using a CAD/CAM glass-fiber post system, the maximal von Mises stress was significantly affected by the bone level, rather than by the dentin thickness. Moreover, this system may be applied to the treatment of a maxillary anterior tooth with a bone level of only 2/3.

Effects of scanning technique on <i>in vitro</i> performance of CAD/CAM-fabricated fiber posts

“…To our knowledge, no previous study has investigated direct scanning of the post space. Several studies used different indirect techniques for digital data acquisition of the post space (23)(24)(25)(26)(27)(28)34). Lee et al scanned stone models of the post space to custom-fabricate the fiber post and core restoration (23,24).…”

“…In a study by Bittner et al (34), acrylic resin patterns were scanned to CAD/ CAM-fabricate a zirconia post and core. The scanning methods used were not specified in recent studies of CAD/CAM glass fiber posts by Chen et al (27,28). In addition, no studies have examined the usefulness of procedures for digital acquisition of the post space.…”

“…Chen et al (26) validated this technique by inserting a 1-piece glass fiber dowel-and-core fabricated with CAD/CAM technology in two patients. Additionally, two recent studies by Chen et al tested von Misses stress level in dentin of extracted maxillary canines restored with CAD/ CAM glass fiber posts and lithium disilicate crowns (27,28). However, few in vitro or in vivo studies have investigated the performance of CAD/CAM-fabricated fiber posts inserted into oval-shaped root canals.…”

“…Digital images of the prepared tooth, which are required for CAD/CAM fabrication of a restoration, can be obtained by direct intraoral scanning, by scanning impressions, or by scanning stone models (25)(26)(27)(28)(29). Impressions and stone replicas can be digitized with high reliability (30).…”

In vitro Results of Scanning Technique on Assessing Cement Thickness and Interfacial Nanoleakage of Luted CAD/CAM-fabricated Fiber Posts

“…Furthermore, fiber-reinforced composite blocks were used to CAD/CAM fabricate the fiber posts for irregularly shaped or large root canals. [ 4 5 6 ] Furthermore, according to the literature, digital images of the prepared tooth required for CAD/CAM fabrication of the restoration can be obtained in three ways: by direct intraoral scanning, by scanning the impressions, or by scanning the stone models. Research has shown that both impressions and stone replicas can be digitized with high reliability.…”