Bacterial Culture and DNA Checkerboard for the Detection of Internal Contamination in Dental Implants

Purpose: The aim of this in vitro study was to evaluate the bacterial leakage along the implant-abutment interface by the conventional bacterial culture and DNA Checkerboard hybridization method. Materials and Methods: Twenty Branemark-compatible implants with a 3.75-mm diameter and external hexagonal platform were randomly placed in two groups of ten implant-abutment assemblies each. One group was used to analyze bacterial counts by DNA Checkerboard hybridization and the other by a conventional bacterial culture. Suspensions of Fusobacterium nucleatum (3 mu l) were injected into the grooved internal cylinders of each implant assembly, and the abutment was connected by a 32 Ncm torque. The combined implant-abutments were individually placed in tubes containing the CaSaB culture medium and incubated in a bacteriological constant temperature oven for 14 days. The samples were observed daily as to the presence of turbidity, and after the designated time the microorganisms were collected from the implant interiors and analyzed by the two methods. Results: After 14 days, six implant-abutment assemblies showed turbidity. Both methods indicated reduced microorganism counts in samples from the interior of the implant-abutment assemblies after incubation in the culture medium; however, the number of counts of F. nucleatum was higher by the DNA Checkerboard method when compared to the group analyzed by conventional bacterial cultures (p < 0.05). Conclusion: The DNA Checkerboard method was shown to be more sensitive than conventional cultures in the detection of microorganisms.