The purpose of this study was to describe the state of the dentition of middle-aged and elderly Chinese in Hong Kong in terms of teeth present, tooth spaces, and prosthetic treatment received. In an oral health survey conducted in 1991 in Hong Kong, a sample of 372 35-44-yr-olds and 537 noninstitutionalized 65-74-yr-olds was interviewed and clinically examined. In all dentate subjects, each tooth was scored for the presence/absence of that tooth, a tooth space of 5.5 mm which had not been treated, or the presence of a denture or pontic replacing that tooth. Each denture was assessed according to a set of criteria. None of the 35-44-yr-olds were edentulous and the mean number of teeth present was 27.5. About 40% of the third molars and about 35% of the mandibular first molars were missing. For only 1% of the missing teeth had space closure resulted in missing teeth not being recorded as tooth spaces or treated tooth spaces. Overall, 72% of the 35-44-yr-olds had no prosthesis, 17% had a bridge or bridges, 12% had a denture or dentures, and 1% had both. Of the 65-74-yr-olds, 12% were edentulous, and the dentate subjects had a mean number of 17 teeth present. About 70% of the molars were missing. Overall, only 29% of the elderly had no prosthesis, 52% had a denture or dentures, 33% had a bridge or bridges, and 13% had both. Only 35% and 28%, respectively, of the middle-aged and elderly denture wearers had no complaint about their dentures.(ABSTRACT TRUNCATED AT 250 WORDS)