Shaping Die For Restoring Molar Crown In Maxillary And Mandible After Its Extended Defect: A Pilot Clinical Trial

Objective:Small scale defect (<200mm3) of molar crown in maxillary and mandible can be restored by matrix filled with amalgam, but extended defect of that is not satisfactorily be filled by matrix due to not restore its anatomic shape and physically masticatory force. Shedding and fracture of obturator following matrix filled with amalgam frequently occur when this kind of artificial molar crown triturates hardish food. The objective of present study was to make a shaping die, according to anatomic shape of human molar crown in maxillary and mandible and its mechanics characteristics, for restoring extended defect of molar crown in maxillary and mandible. The therapeutic effectiveness between shape die and matrix was evaluated and compared after amalgam filled into extended defect of molar crown in maxillary and mandible.Methods:All standard versions (in accordance with human anatomic shape) of molar crown in maxillary and mandible were used to make the shaping die molded with thermoplastics. The patients with extended defect of molar crown in maxillary or mandible were respectively performed by shaping die (n=60) and matrix (n=60) filled amalgam as filling materials. The ratio of successfully filling, perfect shape, an increase in effective chew and shedding and fracture of obturator was compared between two groups after treatment.Results:The comparison between shaping die and matrix group, the ratio of successfully filling was respectively 86.67% and 66.67%(P=0.01); the ratio of perfect shape was respectively 90.00% and 60.00%(P<0.0001); the ratio of an increase in effective chew was respectively 8.56±4.10366 and 2.92±4.34856 (P=0.021); shedding and fracture of obturator were respectively 2 and 14 (P=0.002).Conclusion:Shaping die for restoring molar crown in maxillary and mandible after its extended defect is appreciated in successfully filling, perfect shape, an increase in effective chew and preventing shedding and fracture of obturator, and much effective than matrix supplied at currently market and appropriate for different hospital use. The insufficiency of shaping die for restoring molar crown in maxillary and mandible after its extended defect is that the procedures are more complex, filling materials is relatively less and aesthetics is absent.