CAD/CAM Glass Fiber Posts Improve Fracture Strength and Safety of canine roots: Study
Researchers have discovered in a new study that CAD/CAM-milled glass fiber posts demonstrated higher fracture strength and a lower risk of catastrophic fractures of canine roots indicating improved durability and a more favorable failure pattern.
Computer-aided design/computer-aided manufacturing (CAD/CAM)-milled glass fiber posts offer notable advantages. However, their performance compared to that of prefabricated, composite-reinforced glass fiber posts is controversial. This study aimed to evaluate the fracture strength and fracture patterns of canine roots restored with relined glass fiber posts and CAD/CAM-milled glass fiber posts.
In total, 20 decoronated canine roots underwent endodontic treatment (n = 10). In the relined group (control), prefabricated glass fiber posts (Reforpost Angelus #1, Angelus, Brazil) were relined with a resin composite (Z350, 3M ESPE, USA). In the milled group, the root canal was modeled using a post (Pinjet, Angelus) and red acrylic resin (Pattern Bright Kit, Kota Ind., Brazil). The acrylic resin patterns were scanned and milled from a glass fiber block (Fiber CAD Post & Core, Angelus).
A dual-cure self-adhesive resin luting agent (RelyX™ U200, 3M ESPE) was used for post cementation in both groups. The specimens were subjected to compressive loading, applied at a 45° angle to the long axis of the tooth using a universal testing machine with 200 kgf of compressive force at a crosshead speed of 1 mm/min, until failure.
The failure mode was classified as catastrophic (fracture extended to the middle and/or apical third) or repairable (glass fiber post and/or coronal core or limited to the cervical region). A statistical analysis was performed using an independent samples t-test (α = 0.05).Results: A statistically significant difference was observed in the mean fracture strength, with higher values for the milled group (p = 0.004). Furthermore, the milled group had fewer catastrophic failures.
The CAD/CAM-milled glass fiber posts exhibited greater fracture strength and a reduced incidence of catastrophic fractures.
Reference:
Aguiar PHS, Baroudi K, Walia T, Padmanabhan V, Silva FM, de Abreu ECR, Miranda ME, Vitti RP and Brandt WC (2026) Fracture strength of roots restored with relined and milled glass fiber posts. Front. Dent. Med. 7:1711272. doi: 10.3389/fdmed.2026.1711272
