Modified Glass Ionomer Cement with “Remove on Demand” Properties: An In Vitro Study

Abstract

Objectives: To investigate the influence of different temperatures on the compressive strength of glass ionomer cement (GIC) modified by the addition of silica-coated wax capsules; Material and Methods: Commercially-available GIC was modified by adding 10% silica-coated wax capsules. Test blocks were fabricated from pure cement (control) and modified cement (test), and stored in distilled water (37 °C/23 h). The compressive strength was determined using a universal testing machine under different temperatures (37 °C, 50 °C, and 60 °C). The maximum load to failure was recorded for each group. Fractured surfaces of selected test blocks were observed by scanning electron microscopy (SEM); Results: For the control group, the average compressive strength was 96.8 ± 11.8, 94.3 ± 5.7 and 72.5 ± 5.7 MPa for the temperatures 37 °C, 50 °C and 60 °C respectively. The test group reported compressive strength of 64.8 ± 5.4, 47.1 ± 5.4 and 33.4 ± 3.6 MPa at 37 °C, 50 °C and 60 °C, respectively. This represented a decrease of 28% in compressive strength with the increase in temperature from 37 °C to 50 °C and 45% from the 37 °C to the 60 °C group; Conclusion: GIC modified with 10% silica-coated wax capsules and temperature application show a distinct effect on the compressive strength of GIC. Considerable compressive strength reduction was detected if the temperature was above the melting temperature of the wax core.

Influence of Luting Materials on the Retention of Cemented Implant-Supported Crowns: An In Vitro Study

“…The success rates after dental implant treatment are high [ 23 , 34 , 35 ], and the need for future removal and reparation of implant-fixed restorations will increase [ 11 ]. The choice of cement for implant-fixed restorations can influence implant stability after restoration removal.…”

“…The biological factors are age, systemic health, medication, oral disease [ 4 ], bone support [ 6 ], occlusion [ 7 ], hard and soft peri-implant tissue quality [ 4 ], changes [ 8 ] in bacterial colonization around implants and around teeth, type of the oral hygiene [ 3 , 9 , 10 ], and smoking [ 4 ]. The technical factors include amount of retention [ 11 ], devices for implant-supported prosthesis retention [ 12 ], type of retention force applied [ 13 ], crown and implant abutment materials, geometry, height, type of the surface finishing, surface roughness [ 14 , 15 , 16 ], cleaning method during recementation [ 17 ], and the chemical, physical, bioactive and “remove-on-demand” properties of the luting material [ 11 , 12 , 16 ]. One of the actual topics of interest in the field of biology-driven implant therapy is implant restoration [ 2 , 18 , 19 ], and this topic has induced the development of new methods and luting materials for implant-supported prosthesis retention [ 11 , 20 ].…”

“…There are complications, such as disconnection of cement-retained implant-supported prostheses from abutments; nevertheless, this retention mode is still used because it is an effective option, especially for implant-supported single crowns and short-span fixed dental prostheses [ 18 ], and because of esthetic and economic reasons [ 28 ]. There is a need for the development of new modified luting materials for implant-supported prosthesis retention [ 11 ]. Three luting agent types for cement retention are known: temporary, permanent, and semipermanent [ 11 , 29 , 30 ].…”

“…There is a need for the development of new modified luting materials for implant-supported prosthesis retention [ 11 ]. Three luting agent types for cement retention are known: temporary, permanent, and semipermanent [ 11 , 29 , 30 ]. Temporary cements, with low tensile strength and high solubility, help to avoid damaging the restoration and peri-implant tissues [ 31 , 32 ].…”

“…Semipermanent retention provides adequate retention and retrievability [ 29 ]. For semipermanent retention cements, phase change materials (PCM) were created with a phase transition behavior (solid–liquid) depending on temperature or other physical factors [ 11 , 29 , 30 ]. The matrix of the conventional permanent cement can be changed with activatable microadditives and can acquire new mechanical “remove-on-demand” properties [ 11 , 29 , 30 ].…”