In Vitro Evaluation of Ferrule Effect and Depth of Post Insertion on Fracture Resistance of Fiber Posts

Abstract

Purpose. The analysis of the complex model of fiber post and ferrule is given and studied in this paper. A novel approach and a solution to the evaluation of stress of post and core system within the ferrule effect are proposed. Methods. Sixty freshly extracted premolars were selected for the study. The following experimental groups were therefore defined (n = 10): (1) 5 mm, (2) 7 mm, (3) 9 mm, (4) ferrule-5 mm, (5) ferrule-7 mm, and (6) ferrule-9 mm. Preshaping drills (C) were used to prepare the root canals at 5, 7, and 9 mm in depth. In specimens of groups 3–6 a circumferential collar of tooth structure of 2 mm in height. Fluorocore 2 core build-up material (I) was used for fiber post luting. With the same material, a buildup of 2 mm in height was created. A controlled compressive load (crosshead speed: 0.75 mm/min) was applied by means of a stainless steel stylus (Ø 1 mm) at the coronal end of the post extruding out of the root. Results. In all the tests the level of significance was set at P < 0.05 . Significantly higher fracture strengths were measured in the presence of a ferrule effect. In groups 1, 2, and 3 (ferrule group), the mean fracture values were, respectively, 163,8 N, 270,9 N, and 254,7 N. These data are higher and statistically significantly different when compared with the three groups 4, 5, and 6 (no-ferrule group), in which the values obtained were, respectively, 40,5 N, 41,7 N, and 44,9 N. Conclusion. The ferrule effect in the endodontically treated teeth positively affects the fracture strength of the fiber post. Conversely, post depth insertion did not affect the resistance to fracture.

Influence of the Fiber Post Length on the Fracture Strength of Endodontically Treated Teeth

“…In another study performed by Schiavetti and Gianino [36] on human extracted premolars, fiber post depths of 5, 7 and 9 mm were mechanically tested for fracture resistance; their conclusion was that the insertion depth of the post did not statistically influence the resistance of the treated teeth. These results are similar to our current findings, using only two groups with similar post length (5 and 7 mm).…”

Fracture Resistance of Anterior CAD/CAM Nanoceramic Resin Endocrowns with Different Preparation Designs

“…The results of this study were compared to the results of studies examining post extension in the root canal because the same variable was used which was the intracanal extension, and also the material of the posts used in these studies showed close qualities to the Lava Ultimate accounting for similar bonding qualities and monoblock effect. Schiavetti and Sannino (2012) [26], concluded that post depth insertion did not affect the resistance to fracture. It could be advisable in the rehabilitation of endodontically treated teeth to preserve radicular tissue, reducing the post space preparation, in order to improve the fracture strength of the post with a ferrule length of at least 2 mm.…”

In vitro evaluation of the influence of ferrule effect and post length on the fracture resistance of endodontically treated teeth reinforced with glass fiber post

“…Kết luận của Nissan và cộng sự (2007) chỉ ra rằng độ sâu đặt chốt không ảnh hưởng lên sự kháng gãy của răng khi có sự tồn tại của 2 mm mô răng trên nướu [16]. Schiavetti và cộng sự (2012) khi đánh giá hiệu ứng vành đai và độ sâu đặt chốt lên độ kháng gãy của chốt sợi bằng thử nghiệm kiểm tra lực kháng gãy lên khối composite phục hồi thân răng đã cho rằng sự kháng gãy của chốt sợi không phụ thuộc vào độ sâu đặt chốt mà chịu ảnh hưởng chủ yếu từ hiệu ứng vành đai [17]. Nghiên cứu của tác giả Dejeck và cộng sự (2013) về sự ảnh hưởng của hiệu ứng vành đai và độ sâu đặt chốt lên độ nén ở răng cửa cũng cho thấy lực phân bố lên chân răng ở nhóm có hiệu ứng vành đai giảm đáng kể trong khi nhóm không có hiệu ứng vành đai thì ngược.…”