Retention of radicular posts varying the application technique of the adhesive system and luting agent

Abstract

This study evaluated in vitro the retention of intracanal cast posts cemented with dual-cure resin varying the application method of the primer/adhesive solution and luting agent in the prosthetic space prepared to receive the posts. Sixty endodontically treated maxillary canines had their crowns discarded, and their roots were embedded in acrylic resin. The prosthetic spaces were prepared with Largo burs mounted on a low-speed handpiece coupled to a parallelometer in order to maintain length and diameter of intraradicular posts constant and to guarantee that the preparations were parallel after casting. Two groups (n = 30) were randomly formed according to the device used to apply the adhesive system: microbrush or standard bristle brush (control). Each group was divided into 3 subgroups (n = 10) according to the technique used to place the luting agent into the root canal: using only a lentulo spiral before setting the post, applying it onto the post surface, or combining both methods. After 72 hours, the tensile force required to dislodge each post was determined by a universal testing machine (Instron 4444) set at a speed of 1 mm/min. The results indicated that the use of the microbrush yielded higher bond strength values (0.1740 +/- 0.04 kN) than those recorded for the bristle brush tip (0.1369 +/- 0.04 kN, p < 0.001). Bonferroni's test demonstrated a higher retention (p < 0.001) in radicular post cemented with the technique that combined both methods (lentulo + post: 0.1787 +/- 0.03 kN) than that obtained with lentulo (0.1461 +/- 0.065 kN) or post (0.1416 +/- 0.03 kN) alone. The interactions between the adhesive system and luting agent application techniques presented statistical difference (p < 0.001). It was concluded that the best performance in terms of tensile strength among the tested conditions was obtained when the adhesive system was applied with a microbrush and the luting agent was taken into the root canal with lentulo spirals alone (0.1961 +/- 0.04 kN) and combining both methods (lentulo + post: 0.1911 +/- 0.02 kN).

Influence of remaining coronal structure and finish line on the fracture strength of roots restored with metallic posts

“…12 In the event that these procedures are not possible, it is suggested that a beveled finish line be chosen so that a metal belt can embrace the root. The adhesive technique with resin composite and pre-fabricated fiber posts is recommended because it forms a single block between the root and the filling core.…”

“…The cement was mixed and introduced into the post spaces with a lentulospiral drill using a low-speed handpiece. 12 Cement was also applied on the posts before they were gently seated by finger pressure and held in place for 60 s. The cement was light polymerized for 30 s on each surface (buccal, palatal, mesial and distal), for a total 2-min light polymerization cycle.…”

An evaluation of luting agent application technique effect on fibre post retention

“…Also the viscosity of the resin cement and the way the cement was placed into the post space seemed to be important factors that could affect the complete setting of fibre posts 12 and consequently the strength of the post retentive force. Although the mechanical properties of dual-cure resin cement have been evaluated, little information is available on the role of the application methods of dualcure resin cements into the post space and their effect on the regional bond strength of fibre post.…”

Influência do método de inserção do cimento resinoso na resistência adesiva de pinos de fibra de vidro.

“…Já a seringa tipo Centrix (Centrix Inc.) e ponta aplicadora do tipo Accudose (Centrix Inc.,Shelton, CT, USA) foram originalmente desenvolvidas para inserção de cimento de ionômero de vidro, mas também podem ser utilizadas para a inserção do cimento no interior do canal radicular (11). Outra alternativa comumente utilizada na prática odontológica, pela facilidade e rapidez do método, é a inserção do cimento diretamente sobre o pino, e este, levado ao interior do conduto radicular (12).…”