Repairability of CAD/CAM high-density PMMA- and composite-based polymers

Abstract

OBJECTIVE The study aimed to analyse the shear bond strength of computer-aided design and computer-aided manufacturing (CAD/CAM) polymethyl methacrylate (PMMA)-and compositebased polymer materials repaired with a conventional methacrylate-based composite after different surface pretreatments. METHODS Each 48 specimens was prepared from six different CAD/CAM polymer materials (Ambarino high-class, artBloc Temp, CAD-Temp, Lava Ultimate, Telio CAD, Everest C-Temp) and a conventional dimethacrylate-based composite (Filtek Supreme XTE, control) and aged by thermal cycling (5000 cycles, 5-55°C). The surfaces were left untreated or were pretreated by mechanical roughening, aluminium oxide air abrasion or silica coating/silanization (each subgroup n = 12). The surfaces were further conditioned with an etchrinse adhesive (OptiBond FL) before the repair composite (Filtek Supreme XTE) was adhered to the surface. After further thermal cycling, shear bond strength was tested, and failure modes were assessed. Shear bond strength was statistically analysed by twoand one-way ANOVAs and Weibull statistics, failure mode by chi(2) test (p 0.05). RESULTS Shear bond strength was highest for silica coating/silanization > aluminium oxide air abrasion = mechanical roughening > no surface pretreatment. Independently of the repair pretreatment, highest bond strength values were observed in the control group and for the composite-based Everest C-Temp and Ambarino high-class, while PMMA-based materials (artBloc Temp, CAD-Temp and Telio CAD) presented significantly lowest values. For all materials, repair without any surface pretreatment resulted in adhesive failures only, which mostly were reduced when surface pretreatment was performed. CONCLUSIONS Repair of CAD/CAM high-density polymers requires surface pretreatment prior to adhesive and composite application. However, four out of six of the tested CAD/CAM materials did not achieve the repair bond strength of a conventional dimethacrylate-based composite. CLINICAL RELEVANCE Repair of PMMA-and composite-based polymers can be achieved by surface pretreatment followed by application of an adhesive and a conventional methacrylate-based composite. Conclusions: Repair of CAD/CAM high-density polymers requires surface pretreatment prior to adhesive and composite application. However, four out of six of the tested CAD/CAM materials did not achieve the repair bond strength of a conventional dimethacrylate-based composite.Clinical Relevance: Repair of PMMA-and composite-based polymers can be achieved by surface pretreatment followed by application of an adhesive and a conventional methacrylate-based composite.2

Bonding effectiveness of self-adhesive and conventional-type adhesive resin cements to CAD/CAM resin blocks. Part 1: Effects of sandblasting and silanization

“…However, for the CAD/CAM resin materials, micromechanical retention seemed to be essential not only for initial bond strength but also long-term durability. As with the present study, Wiegand et al confirmed that adhesive conditioning alone for CAD/CAM polymer restorations without micromechanical retention is not adequate to obtain sufficient bond strength 18) . The findings are supported by the result that a frequency of adhesive failures in the Sb+Si subgroup was the smallest observed in all subgroups.…”

Load-bearing capacity of novel resin-based fixed dental prosthesis materials

“…Previous studies have reported that industrially fabricated CAD/CAM materials have a homogeneous structure and thereby, a reduced risk of porosities and superior mechanical strength 33,34) . The dramatic difference in the present load bearing capacity values between the groups could be related with this phenomenon.…”

Effect of surface treatments on shear bond strength of resin composite bonded to CAD/CAM resin-ceramic hybrid materials

“…These methods are commonly used surface treatments during intraoral repair of ceramic restorations 1821. However, for CAD/CAM resin-ceramic hybrid materials, there is no agreement on the repair protocol that leads to favorable clinical outcome 713272829. These studies investigated an additional use of adhesive system to provide chemical bonding as well as mechanical pretreatment.…”