biofilm – An aggregation of microorganisms in which cells adhere to each other, forming small communities that are held together by an extracellular polymeric matrix. Different communities are co-dependent on each other, and the whole biofilm forms a defensive mechanism requiring much higher concentrations of antimicrobials to control its growth. Dental plaque is a previous name for what is now called the biofilm. However, recent understanding of the biofilm leads to the development of the "micrbiome" ecological model; because bacteria are normally present in the oral cavity.

bitewing radiography – The process of creating radiographic images of the posterior teeth, with the specific objective of identifying carious lesions on the proximal surfaces that may be inaccessible to visual and tactile examination. Less mineralized tissues permit more x-rays to pass through (radiolucency) and therefore create greater levels of exposure to radiographic film or a digital transducer.

demineralization – The chemical process by which minerals (mainly calcium) are removed from the dental hard tissues - enamel, dentin, and cementum. The chemical process occurs through dissolution by acids or by chelation, and the rate of demineralization will vary due to the degree of supersaturation of the immediate environment of the tooth and the presence of fluoride. Under optimal conditions, the minerals may be replaced through the process of remineralization.

dental plaque – An organized community of many different microorganisms that forms itself into a biofilm and is found on the surface of the tongue and all hard surfaces in the oral cavity. Dental plaque is present in all people and can vary from being comprised of totally healthy microorganisms (commensals) to being very harmful (pathogenic), predisposing the patient to dental caries or periodontal diseases. Note: Dental plaque is not food debris, nor does it contain food debris. Dental plaque can only be completely removed by mechanical means such as toothbrushing or prophylaxis. Food debris can be removed by rinsing.

lesion – Any abnormal well-circumscribed change in any tissue due to disease or injury. In terms of dental caries, the lesion is the part of the tooth that has undergone the caries process. Therefore, this part of the tooth includes demineralized enamel and dentin, the cavity itself where tissue has been lost (not a feature of a very early stage lesion), and softened tissue that can be removed by a dental hand instrument. Microscopically, the lesion extends beyond the cavity.

microbiome – Normal bacterial species that are present at all the times in the human body and their presence is necessary for maintaining health, especially in the digestion of foods and in keeping away detrimental bacterial species.

microporosity – An area of the enamel surface that has developed a level of porosity not clearly visible to the naked eye; the resulting change in surface texture may be detected by a dental probe/explorer. Microporosity is a sign of demineralization, and could be indicative of the initiation of a caries lesion.

remineralization – The chemical process by which minerals (mainly calcium) are replaced into the substance of the dental hard tissues - enamel, dentin and cementum. The process requires an ideal environment that includes supersaturation with calcium and phosphate ions, and adequate buffering. In the presence of fluoride, the remineralization process is enhanced.

tomography – Use of radiography to create a focused image of structures in a defined plane or 'slice,' ignoring all other structures that would normally appear in three dimensions. A series of tomography scans can help build a clearly focused 3D image.