title: [Effect of gap size between tooth and restorative materials on microbiolism based caries in vitro].
abstract: OBJECTIVE
  To evaluate the effect of gap size between tooth and restorative materials on microbiolism based caries in vitro.
  
  
  METHODS
  Tooth blocks made of human molars without caries and the same size composite resin blocks were selected and prepared. Tooth-resin matrix was mounted on resin base with a gap size of 0, 25, 50, 100, 190, 250 µm and a control group was dealed with adhesive system. Six experimental groups and one control group were included, with 8 samples in one group and a total of 56 samples. The samples were cultured by a 14-day sequential batch culture technique. The development of outer surface lesion and wall lesion was assessed with confocal laser scanning microscope (CLSM) by measuring the maximum lesion depth, fluorescence areas and average fluorescence value. The data were collected and statistically analyzed. The deposits of the tooth-restoration interface and the development of the carious lesion were observed by scanning electron microscope (SEM).
  
  
  RESULTS
  Most groups showed outer surface lesion and wall surface lesions observed by CLSM and SEM except 2 samples in control group. There was no significant difference on the outer surface lesion (P > 0.05). The maximum lesion depth [(1145.37 ± 198.98), (1190.12 ± 290.80) µm respectively], the maximum lesion length, fluorescence areas and average fluorescence value of 190 and 250 µm groups' wall lesions were significantly higher than the 0, 25, 50 and 100 µm groups [the maximum lesion depth was (205.25 ± 122.61), (303.87 ± 118.80), (437.75 ± 154.88), (602.87 ± 269.13) µm respectively], P < 0.01. With the increase of the gap size, the demineralization developed more seriously. While the maximum lesion depth, the maximum lesion length and fluorescence areas of 0, 25, 50 µm groups' wall lesions were of no significant difference.
  
  
  CONCLUSIONS
  There was close relationship between gap size and wall lesion when the gap was above 100 µm at tooth-composite resin interface. The existence of gap was the main influencing factor on the development of microbiolism based caries lesion.
authors.affiliation: Department of Endodontics, Capital Medical University School of Stomatology, Beijing 100050, China.
authors.forename: Wen-bin
authors.initials: WB
authors.lastname: Lu
authors.forename: Yun
authors.initials: Y
authors.lastname: Li
mesh_terms: D000180:Acrylic Resins; D000293:Adolescent; D000328:Adult; D003188:Composite Resins; D001840:Dental Bonding; D003731:Dental Caries / Q000209:etiology* / Q000382:microbiology / Q000473:pathology; D003743:Dental Enamel / Q000473:pathology; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent; D006801:Humans; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000473:pathology; D011140:Polyurethanes; D013295:Streptococcus mutans / Q000472:pathogenicity; D055815:Young Adult
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes