title: [A clinical study of Palodent posterior teeth matrix system].
abstract: OBJECTIVE
  To set up a clinical evaluation method for the matrix system, and compare two matrix systems, Palodent and circumferential, by this method.
  
  
  METHODS
  101 molars and premolars with class II cavities, which were suitable for resin filling without shift and incline of the adjacent teeth, were randomly divided into study group (Palodent) and control group (circumferential). There were 79 single cavities and 22 paired cavities. One doctor-in-charge completed all cavities filling. Probes were used to test overhang of the filling. Dental floss was used to detect the proximal contact index before and after cavity preparing and immediately and one week after cavity filling. Questionnaires were filled in by patients immediately and one week afrer cavity filling. The tooth models of the filling side were taken, then two doctors-in-charge were responsible for establishing the model evaluation index and one of them conducted the evaluation for all of the models. SPSS 14.0 software was used to analyze the data.
  
  
  RESULTS
  An evaluation system including questionnaire, clinical examination and tooth model evaluation was set up. There were nine indexes in this system. Moreover, this clinical evaluation system was used in this study. It was found that there were no differences on questionnaire and overhang indexes between the two groups. Palodent matrix system got tighter proximal contact than traditional circumferential matrix system. When filling the paired posterior teeth, Palodent matrix system formed better marginal ridge than circumferential matrix system.
  
  
  CONCLUSIONS
  Palodent matrix system is better than circumferential matrix system in filling the paired posterior teeth.
authors.affiliation: Dept. of General Dentistry, School and Hospital of Stomatology, Peking University, Beijing 100081, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yong
authors.forename: Run-Quan
authors.initials: RQ
authors.lastname: Zhang