Dental composition comprising(a) a homogeneous phase comprising monomer combinations (i) and (ii), (i) and (iii), (ii) and (iii), or (i), (ii) and (iii), or comprising monomer (iii), wherein(i) represents one or more compounds having one or more radically polymerizable carbon-carbon double bonds；(ii) represents one or more compounds having one or more cationically polymerizable groups； and(iii) represents one or more compounds having a combination of one or more radically polymerizable carbon-carbon double bonds and one or more cationically polymerizable groups；(b) an initiator system comprising(iv) one or more radical polymerization initiator of the following formula (I):whereinM is Ge or Si；R1, R2 and R3 may be the same or different, independently represent an organic group, and R4 represents a hydrogen atom, an organic or organometallic group；provided that when R4 is a hydrogen atom, the initiator system further comprises a sensitizer compound having a light absorption maximum in the range from 300 to 600 nm；(v) a cationic polymerization initiator, which is a compound selected from the following formula (II), (III) and (IV):whereinR5 and R6, which may be the same or different, independently represent an aryl group which may have a substituent； andY represents an anion；whereinR7, R8 and R9 which may be the same or different, independently represent an aryl group which may have a substituent； andY- represents an anion；R10, R11, R12 , and R13 which may be the same or different, independently represent an alkyl or aryl group which may have a substituent； andY- represents an anion.
