Plaque is an irritant to your gums and can cause gingivitis (inflammation of the gums). In addition, if plaque lingers on tooth surfaces for too long, the acidic by-products created by the bacteria eventually “melt” the tooth and create soft spots – these are called cavities, which necessitates fillings. People with good oral hygiene leave very little plaque on their teeth by brushing and flossing regularly, which results in fewer cavities and healthier gums.