5
Plaque microbiology
Table 5.1 Different methods of examining plaque microbial composition.
| Method | Advantages | Disadvantages |
| Microscopy | Recognition of morphological types Determine spatial arrangements of organisms Recent novel, sophisticated applications, e.g. atomic force microscopy gives very high image resolution |
Slow and labour intensive Precise speciation using immunological or hybridisation methods only possible for a few species in sample |
| Culture – predominant | Can detect unrecognised species Provides cultures for further analysis |
Very labour intensive Expensive Some uncultivable species Difficult to culture spirochaetes |
| Culture – selective media | Can detect specific species | As above Need to know which species to investigate Few suitable media Limited species identification |
| Immunofluorescence, ELISA | Quite specific Rapid Cheaper than culture Can distinguish species Can provide counts or proportions of specific species |
Limited numbers of monoclonal or polyclonal antisera available Takes time to develop Relatively small numbers can be run |
| PCR | Reasonable sensitivity Quite specific With appropriate primers can detect very small numbers of species present Rapid |
Dichotomous (i.e. detects presence/absence not quantities) Expensive Depends on amplification Not suitable for large numbers of species in large numbers of samples |
| Real-time PCR | Quantitative Sensitivity* Specificity† |
Relatively slow As above, limited numbers can be processed |
| DNA–DNA hybridisation | Quantitative Sensitivity* Specificity† Low likelihood of cross-reactions with other species |
Only detects species for which probes are available Modest numbers of species for modest number of samples |
| Checkerboard DNA–DNA hybridisation | Quantitative Sensitivity* Specificity† Can use whole sample without dilution or amplification by PCR Large numbers of species and samples Ine/> |
Stay updated, free dental videos. Join our Telegram channel
VIDEdental - Online dental courses
