The potential of a resin-composite to be cured to a 4mm depth.
OBJECTIVE
The potential of a recently marketed resin-based composite (RBC), namely X-tra fil (shade A3), which claims to be amenable to curing to a depth of 4mm was investigated.


METHODS
Disc-shaped specimens (11mm diameter, 2mm thickness) of Filtek Z250, Admira and X-tra fil were tested in bi-axial flexure to determine the strength. Water sorption, water solubility and Vickers hardness measurements were determined following short-term (0.1, 0.5, 1, 4, 24 and 48h) and medium-term (1, 4, 12 and 26 weeks) water immersion on disc-shaped specimens (11mm diameter, 1mm thickness). The top (t) 0-1mm depth and bottom (b) 3-4mm depth of X-tra fil were tested for water sorption, water solubility and Vickers hardness measurements. In addition an analysis of pulpal cell cytotoxicity at 1, 2, 3, 7 and 14 days was also performed on the RBCs.


RESULTS
No significant differences in the bi-axial flexure strength or top to bottom hardness ratios were evident between the materials examined. However, the water sorption and water solubility values obtained for Filtek Z250 (12.3+/-1.8 and 2.7+/-1.6microg/mm3, respectively) and Admira (16.0+/-1.5 and 4.3+/-0.2microg/mm3, respectively) were increased compared with X-tra fil (t) (5.4+/-0.7 and 0.8+/-0.2microg/mm3, respectively) and X-tra fil (b) (6.8+/-0.6 and 2.4+/-1.1microg/mm3, respectively) but within the ISO specification standard of < or =40 and < or =7.5microg/mm(3), respectively. No statistically significant differences were identified on cell viability between the RBCs used in the current study.


CONCLUSIONS
The manufacturer claims that the recently marketed material X-tra fil could be cured to a depth of 4mm appear to be vindicated and the performance in terms of flexure strength, water uptake and biocompatibility are comparable with conventional RBCs.
Materials Science Unit, Division of Oral Biosciences, Dublin Dental School and Hospital, Trinity College Dublin, Dublin 2, Ireland. garry.fleming@dental.tcd.ie
Garry J P
GJ
Fleming
Mumtaz
M
Awan
Paul R
PR
Cooper
Alastair J
AJ
Sloan
D000818:Animals; D002460:Cell Line; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects* / Q000633:toxicity; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D004548:Elasticity; D006244:Hardness; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects* / Q000633:toxicity; D051379:Mice; D044367:Phase Transition; D018583:Pliability; D012833:Siloxanes / Q000737:chemistry / Q000528:radiation effects / Q000633:toxicity; D012995:Solubility; D017155:Wettability
D003188:Composite Resins; C444701:Filtek Z250; D008689:Methacrylates; D012833:Siloxanes; C529733:X-tra fil composite resin; C479084:admira