Fracture Strength of Weakened Anterior Teeth Associated to Different Reconstructive Techniques

Abstract

This study evaluated the fracture strength of endodontically treated teeth submitted to reconstructive techniques through dynamic and static tests. Forty human anterior teeth were divided into 4 groups (n=10): GNW (non-weakened) -root restored with glass fiber post (GFP), GW -weakened root restored with GFP, GDA -weakened root restored with direct anatomic GFP, and GIA -weakened root restored with indirect anatomic GFP. The teeth were endodontically treated considering that experimental groups (GW, GDA and GIA) simulated weakened roots for restoration with GFP using different techniques. The GFP was luted with resin cement and the coronal portion was restored with composite resin and metallic crowns. All samples were submitted to chewing simulation at 60 cycles/ min in a total of 300,000 cycles. The survival samples were further exposed to compressive loading at a crosshead speed of 1.0 mm/min in a universal testing machine. The load was applied at 135° to the long axis of the tooth until failure. Data were analyzed by ANOVA (α=0.05). After chewing simulation were observed: GNW: 100% of survival roots; GW: 70% of survival roots, and GDA and GIA: 80% of survival roots. The mean fracture strength values (N) were 280.6 (GNW), 239.0 (GW), 221.3 (GDA), and 234.1 (GIA) without significant difference among the groups (p=0.7476). The results suggested similar fracture strength in both weakened and non-weakened teeth regardless the reconstructive technique of root internal wall. Higher incidence of catastrophic fracture was observed in weakened teeth without restoration of the root internal wall.

Restorative strategies for weakened roots: Systematic review and Meta-analysis of in vitro studies

“…Restorative strategies for weakened roots: Systematic review and Meta-analysis of in vitro studies Braz Dent Sci 2019 Jan/Mar; 22(1)…”

“…The flowchart of the systematic review is shown in Figure 1. A total of 6 articles [7,10,[19][20][21][22] were included in the analysis. Four articles [7,10,20,21] evaluated CPC, FP, and AP while one [19] presented only CPC and FP groups and one compared FP and AP [22].…”

“…All studies used resin cement for post cementation. Four [7,10,21,22] studies used dual-cured resin cement. One [19] study used dual-polymerized self-adhesive cement and the other study [20] used self-curing resin cement.…”

“…Two studies weakened the specimens until a 7mm depth [19,21], one article weakened until 9mm [20], one until 5mm [7], one article weakened until 6mm [10] and one until 10mm [22]. Regarding the thickness of weakening, five studies [7,[19][20][21][22] used 1mm of thickness and one study [10] used 0.5mm.…”

“…Only one study did not perform the specimens aging [19], four studies made the aging of all specimens [10,[20][21][22], and one study compared the effect with and without aging [7].…”