Evaluation of Surface Roughness of Ceramic and Resin Composite Material Used for Conservative Indirect Restorations, after Repolishing by Intraoral Means.

PURPOSE: To evaluate and compare the mean surface roughness (Ra) of one ceramic and one resin composite material used for indirect restorations, after grinding and repolishing by intraoral means. MATERIALS AND METHODS: The materials used were the lithium disilicate glass ceramic IPS e.max Press (EMP) and the indirect resin composite restoration system Gradia (GR). Twelve specimen disks were prepared from each material according to the manufacturer of each material. Five initial measurements of the Ra (Ra1 ) were made on each specimen as a referral basis, and the specimens were ground with a fine (red) diamond bur. The specimens were repolished using (a) Komet Dialite Polishing Kit for EMP and (b) Enhance Finishing and Polishing System and Prisma Gloss Polishing Paste for GR. Five final Ra (Ra2 ) measurements were performed on each specimen. All measurements were made using a laser profilometer. Scanning electron microscopy (SEM) was also used to visualize the initial surface morphology and the morphological changes on the specimens' surface after repolishing. RESULTS: A highly significant difference was found between Ra1EMP and Ra2EMP (p < 0.001), between Ra1GR and Ra2GR (p < 0.001), as well as between Ra2EMP and Ra2GR (p < 0.001), when compared in pairs. A highly significant difference (p < 0.001) was also found between ΔRaEMP and ΔRaGR , with ΔRaGR being higher than ΔRaEMP . The RaGR values were higher than the RaEMP values at all times. SEM revealed that both EMP and GR repolished surfaces presented with irregularities; however, in GR specimens major voids and craters were present. CONCLUSIONS: EMP was found to perform better when polished by intraoral means compared with GR. Both materials exhibited Ra2 above the critical threshold for increased plaque accumulation and periodontal inflammation. If enamel-to-enamel roughness found in occlusal contact areas is considered as baseline, both materials were clinically acceptable after repolishing.

Water sorption and water solubility of self-etching and self-adhesive resin cements.

STATEMENT OF PROBLEM: The long-term success of indirect restorations depends on the clinical behavior of luting cements. In the oral environment, properties such as water sorption and solubility negatively affect the cements' clinical performance over time, jeopardizing the restoration's longevity. PURPOSE: The purpose of this in vitro study was to compare the water sorption and solubility characteristics of self-etching, self-adhesive, and conventional resin cements. MATERIAL AND METHODS: One conventional (Calibra), 1 self-etching (Panavia F), and 2 self-adhesive (Clearfil SA, G-Cem Automix) dual-polymerized resin cements were used. Fourteen disks of each material were prepared. Water sorption and solubility were calculated according to International Organization for Standards (ISO) specification 4049:2009. RESULTS: According to the water sorption test, all materials were found to interact with water. No statistically significant differences were found between the water sorption of Panavia F and Clearfil SA (P=.911). These cements exhibited higher water sorption values than the other materials (P<.05), whereas Calibra exhibited the lowest values (P<.05). Statistically significant differences were found among all materials regarding their water solubility (P<.05). Panavia F and Clearfil SA were found to have higher solubility values than the other materials. G-Cem Automix and Calibra exhibited negative solubility. However, all water sorption and solubility values were below the threshold values proposed by the ISO standard. CONCLUSIONS: Within the limitations of the present in vitro study, the interaction of resin cements with water is not type-related (conventional, self-etching, or self-adhesive).

Water sorption and solubility of four self-etching, self-adhesive resin luting agents.

PURPOSE: To evaluate and compare the water sorption and water solubility of four self-etching, self-adhesive resin luting agents. MATERIALS AND METHODS: Four self-etching, self-adhesive resin luting agents (RelyX Unicem, Maxcem, Biscem, Multilink Sprint) and one classic resin luting agent (Multilink Automix) as a control group were used. Twelve disks (8 mm x 1 mm) of each material were prepared according to ISO 4049. Water sorption and solubility were calculated, using the formulae which the ISO 4049 specification provides. RESULTS: Maxcem and Biscem were found to have very high water sorption values. RelyX Unicem and Multilink Sprint exhibited water sorption values only slightly higher than the control group. Regarding water solubility, the greater mass loss was found for Maxcem. Multilink Sprint exhibited no mass change. Biscem was found to have low solubility values, whereas RelyX Unicem and Multilink Automix exhibited negative solubility. CONCLUSION: Multilink Sprint and RelyX Unicem were found to comply with the ISO requirements regarding water sorption and solubility, while Maxcem and Biscem did not. Materials of the same group exhibited very different behavior during their interaction with water.

Curing efficiency of four self-etching, self-adhesive resin cements.

OBJECTIVES: To evaluate the degree of cure (%DC) of four self-etching, self-adhesive resin cements, and one conventional resin cement, in their self- and dual-curing mode. METHODS: The self-etching, self-adhesive resin cements studied were RelyX Unicem (3M ESPE AG), Maxcem (Kerr Corporation), Biscem (Bisco, Inc.) and Multilink Sprint (Ivoclar Vivadent AG) and the classic resin cement was Multilink Automix (Ivoclar Vivadent AG). Twelve specimens of each material (1.8 mm x 4 mm x 4 mm) were prepared in room temperature (23+/-1) degrees C following the manufacturers' instructions. Six of them were treated as dual-cured, thus irradiated for 20 s with a halogen light curing unit and left undisturbed for 5 min. The other six were treated as self-cured and were not irradiated, but left in dark and dry conditions for 10 min. The assessment of the %DC was made using micro-ATR FTIR spectrometry. RESULTS: The %DC in their self-curing mode was very low (10.82-24.93%), with Multilink Sprint exhibiting the highest values among the five. In the dual-curing mode the values obtained were also low (26.40-41.52%), with the exception of Multilink Automix (61.36%). Maxcem was found to have the lowest DC. SIGNIFICANCE: The low %DC found raises questions as to whether these materials can be successfully used in clinical applications, where light attenuation takes place. Increased irradiation times could potentially lead to higher %DC, in applications where light is not completely blocked by the overlying restoration.