Dental composition

Abstract

Dental cement composition comprising a polymerizable polyacidic polymer having repeating units in the polymer backbone, which are represented by the following formula (I)1 (II), and/or (III): wherein X represents O, S, or NR′, whereby R′ represents a hydrogen atom or a straight or branched C 1 -C 6 alkyl group, C 3 -C 6 cycloalkyl group, or C 4 -C 8 cycloalkylalkyl group, Y a group of the following formula (IV), wherein each of L 1 , L 2 , L 3 and L 4 , which are independent from each other represents a single bond, a straight or branched C 1 -C 6 alkylene group, a straight or branched C 1 -C 6 alkenylene, or a straight or branched C 1 -C 20 alkylene group which includes 1 to 8 atoms selected from oxygen and sulfur atoms, X′ represents O, S, or NR″, whereby R″ represents a hydrogen atom or a straight or branched C 1 -C 6 alkyl group, C 3 -C 6 cycloalkyl group, or C 4 -C 8 cycloalkylalkyl group, m is 0 to 3, and n is 1 to 3.

1 . Dental cement composition comprising a polymerizable polyacidic polymer having repeating units in the polymer backbone, which are represented by the following formula (I), (II), and/or (III): 
       
         
           
           
               
               
           
         
         wherein 
         X represents O, S, or NR′, whereby R′ represents a hydrogen atom or a straight or branched C 1 -C 6  alkyl group, C 3 -C 6  cycloalkyl group, or C 4 -C 8  cycloalkylalkyl group, 
         Y a group of the following formula (IV) 
       
       
         
           
           
               
               
           
         
         wherein each of L 1 , L 2 , L 3  and L 4 ,
 which are independent from each other represents a single bond, a straight or branched C 1 -C 6  alkylene group, a straight or branched C 1 -C 6  alkenylene, or a straight or branched C 1 -C 20  alkylene group which includes 1 to 8 atoms selected from oxygen and sulfur atoms, 
 
         X′ represents O, S, or NR″, whereby R″ represents a hydrogen atom or a straight or branched C 1 -C 6  alkyl group, C 3 -C 6  cycloalkyl group, or C 4 -C 8  cycloalkylalkyl group, 
         m is 0 to 3, and 
         n is 1 to 3. 
       
     
     
         2 . The dental cement composition according to  claim 1 , wherein the polymerizable polyacidic polymer is obtainable by a process comprising the steps of
 (i) copolymerizing a mixture containing acrylic acid and one or more monomers selected from the group of maleic anhydride and itaconic anhydride, and   (ii) reacting the reaction product with HXY, wherein X and Y are as defined in  claim 1 .   
     
     
         3 . The dental cement composition according to  claim 2 , wherein said polymerizable polyacidic polymer is obtainable by copolymerizing a mixture containing acrylic acid and itaconic acid anhydride. 
     
     
         4 . The dental cement composition according to any one of the preceding claims, wherein XY is —OCH 2 C(═CH 2 )COOH. 
     
     
         5 . The dental cement composition according to any one of the preceding claims, wherein the polymerizable polyacidic polymer is water-soluble. 
     
     
         6 . The dental cement composition according to any one of the preceding claims, which contains a polymerizable polyacidic polymer having repeating units represented by the formula (I) wherein a portion of the groups Y is a group of the following formula (V) 
       
         
           
           
               
               
           
         
         wherein 
         L 5  represents a single bond or a straight or branched C 1 -C 6  alkylene group, 
         L 6  represents a straight or branched C 1 -C 3  alkylene group, and 
         m is as defined in  claim 1 . 
       
     
     
         7 . The dental cement composition according to any one of the preceding claims, which further comprises a polymerization initiator system and optionally a polymerizable monomer having at least two polymerizable functional groups. 
     
     
         8 . The dental cement composition according to any one of the preceding claims which further comprises a particulate glass comprising
 a. 20-25% by weight of silica   b. 20-25% by weight of alumina   c. 18-21% by weight of CaO plus SrO   d. 13-18% by weight of zinc oxide   e. 14-18% by weight of P 2 O 5      f. 4-7% by weight of fluoride,   
       and wherein the content of Na 2 O is less than 1% by weight. 
     
     
         9 . The dental cement composition according to any one of the preceding claims, wherein the mean particle size of the particulate glass is in the range of from 0.1 to 100 μm. 
     
     
         10 . The dental cement composition according to any one of the preceding claims, wherein said polymerizable polyacidic polymer a mean molecular weight, Mw, between 10000 and 500000. 
     
     
         11 . Process for preparing a polymerizable polyacidic polymer having repeating units in the polymer backbone which are represented by the following formula (I) and/or (II): 
       
         
           
           
               
               
           
         
         wherein 
         X represents O, S, or NR′, whereby R′ represents a hydrogen atom or a straight or branched C 1 -C 6  alkyl group, C 3 -C 6  cycloalkyl group, or C 4 -C 8  cycloalkylalkyl group, 
         Y a group of the following formula (IV) 
       
       
         
           
           
               
               
           
         
         wherein each of L 1 , L 2 , L 3  and L 4 ,
 which are independent from each other represents a single bond, a straight or branched C 1 -C 6  alkylene group, a straight or branched C 1 -C 6  alkenylene, or a straight or branched C 1 -C 20  alkylene group which includes 1 to 8 atoms selected from oxygen and sulfur atoms, 
 
         X′ represents O, S, or NR″, whereby R″ represents a hydrogen atom or a straight or branched C 1 -C 6  alkyl group, C 3 -C 6  cycloalkyl group, or C 4 -C 8  cycloalkylalkyl group, 
         m is 0 to 3, and 
         n is 1 to 3, 
         said process comprising the steps of 
         (i) copolymerizing a mixture containing acrylic acid and one or more monomers selected from the group of maleic anhydride, itaconic anhydride, and 
         (ii) reacting the reaction product of (i) with HXY, wherein X and Y are as defined in  claim 1 . 
       
     
     
         12 . Process for preparing a polymerizable polyacidic polymer having repeating units in the polymer backbone which are represented by the following formula (III) 
       
         
           
           
               
               
           
         
         wherein 
         X represents O, S, or NR′, whereby R′ represents a hydrogen atom or a straight or branched C 1 -C 6  alkyl group, C 3 -C 6  cycloalkyl group, or C 4 -C 8  cycloalkylalkyl group, 
         Y a group of the following formula (IV) 
       
       
         
           
           
               
               
           
         
         wherein each L 3  and L 4  
 which are independent from each other represents a single bond, a straight or branched C 1 -C 6  alkylene group, a straight or branched C 1 -C 6  alkenylene, or a straight or branched C 1 -C 20  alkylene group which includes 1 to 8 atoms selected from oxygen and sulfur atoms, 
 
         X′ represents O, S, or NR″, whereby R″ represents a hydrogen atom or a straight or branched C 1 -C 6  alkyl group, C 3 -C 6  cycloalkyl group, or C 4 -C 8  cycloalkylalkyl group, 
         m is 0 to 3, and 
         n is 1 to 3, 
         said process comprising the steps of reacting a carboxylic acid anhydride of YCOOH, wherein Y is as defined in  claim 1 , with a polymer or copolymer containing repeating units of the following formula (V): 
       
       
         
           
           
               
               
           
         
         wherein X is as defined in  claim 1 . 
       
     
     
         13 . Polymerizable polyacidic polymer obtainable according to the process of  claim 11  or  12 . 
     
     
         14 . Use of the polymerizable polyacidic polymer as defined by  claim 13  in a dental cement composition.