The purpose of the present study was to investigate plaque accumulation and inflammatory changes in the mucosa beneath fixed bridge pontics of various materials, in patients cleaning the infrapontic space daily. Fixed bridges with a tight but non-compressive contact to the mucosa in the pontic area and with interchangeable test specimens placed in the pontic base were constructed for five patients. During 4-wk periods the following materials were tested: alloys with a high or a low gold content, silver-palladium, cobalt-chromium, nickel-chromium and also a dental porcelain or a composite restorative resin. Between the test periods a "sanitary pontic" was used to enable recovery of the alveolar mucosa. Clinical examinations including exudate measurements demonstrated that the alveolar mucosa remained healthy irrespective of the material used when the dental floss was used regularly. The amount of plaque on the test specimens of the seven dental materials showed no consistent differences. The composition of the bacterial deposits showed no regular pattern. This investigation has demonstrated that patients maintaining a high standard of oral hygiene are able to prevent the development of inflammatory changes in the alveolar mucosa in contact with fixed bridge pontics irrespective of the pontic material used.