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In this study the perception of chewing is investigated in forty-three subjects with a shortened dental arch (SDA) by means of an interview. A group of fifty-four subjects with a complete dentition was used as a control group. The aim was: (i) do subjects with a SDA have a higher risk of chewing problems, and (ii) do they have different food perception and food selection leading to change in their diet? The results show that for subjects with a SDA the chewing function, food perception, food selection and actual food consumption are hindered within an acceptable degree.

The currently known classifications for partially edentulous arches lack completeness of major findings relevant for planning prosthodontic therapy. A classification to assess the remaining function of the partially endentulous arch will be proposed, based on the number of teeth and position and length of the interdental connections.

The purpose of the present study was to investigate the dental state of the elderly, to provide a subjective appraisal of their chewing ability and their inability to eat certain foods because of their poor dental state. The subjects were 480 residents of 24 municipal old people's homes in different parts of Finland. Of the subjects, 153 were men and 327 women, and their ages ranged from 65 to 100 years. The methods used were clinical examination and interview. The clinical examination revealed that 68% of the subjects had no natural teeth, and 22% had neither natural nor artificial teeth. The number of teeth in dentate subjects was small (average 7.6), and the condition mostly poor. Only 2% had any serviceable counterparts. 51% of the subjects wore dentures: 57 subjects in the maxilla alone, three in the mandible alone and 186 in both maxilla and mandible. 41% said that because of their teeth they were unable to eat some foods they would have liked to eat, crisp bread being mentioned most often as such a food (85% of those with chewing difficulties). Edentulous subjects and dentate subjects wearing both maxillary and mandibular dentures said more often than those without dentures that they could eat everything; those without any teeth had most often (59%) to avoid some foods. More attention should be given to the dental condition and the masticatory function of the elderly, especially of those living in institutions, to ensure that they are comfortable physically, psychologically, and socially for the rest of their lives.

The activity of leucine amine peptidase, glutamate piruvate transaminase was increased and those of glutamate dehydrogenase and lactate dehydrogenase decreased locally in the region with functional traumatic overload and increased mastication activity (MA) in patients periodontium as related to that in patients with nonfunctioning link in dentition and reduced MA. ATR contents in patients with functional traumatic overload and generalized periodontitis was substantially increased as compared to those in other groups of subjects.

In this study the effect of free-end removable partial dentures (RPD) on oral function was investigated by comparing subjects with shortened dental arches (SDA, n = 55) and a group of subjects with SDA and RPD (n = 25). In addition, a group of subjects were selected who had worn an RPD in the past (n = 19). All subjects had a remaining natural dentition consisting of an intact front region and three to five occlusal units (OU) in the posterior area. On the whole, subjects with RPD had less natural OU compared with subjects without RPD. However, this is also true for those who had worn an RPD in the past. The oral functions of subjects with SDA did not differ significantly when compared with subjects with SDA and RPD. Significantly more subjects who had an RPD in the past reported a limited mobility of the mandible, an impaired chewing capacity and chewing with the front teeth. They also reported more aesthetic complaints due to missing posterior teeth. It is concluded that within the populations investigated in this study oral function is not evidently improved by the insertion of a free-end RPD.

With increasing emphasis being placed on precision in the construction of prostheses the importance of the visco-elastic characteristics of tooth support should be understood. Since the tooth returns to its resting position quite slowly, especially when repeated or sustained forces have been applied, an impression prepared prior to fully recovery will convey erroneous relationships of the tooth with its neighbours to the working model and, eventually, to the prosthesis. Such an error has been identified in young human subjects when inter-dental wedges, gingival retraction cord, and rubber dam are placed. The preparation of conventional alginate impressions in special trays can displace abutment teeth to a clinically significant degree as was recorded for seven partially dentate patients. Simple precautions will circumvent these potential sources of error.

Methods for studying efficiency and the results of studies using self-assessment and laboratory tests in subjects with various patterns of tooth loss are reviewed. It is concluded that age-related impairment of the dentition explains most of the decline in masticatory efficiency, while age per se has little influence. Many edentulous individuals are oral invalids and even when provided with optimal complete dentures their chewing efficiency is much lower than in those with natural teeth, with fixed prostheses on natural teeth, or with osseointegrated oral implants. The maintenance of a reasonable number of healthy natural teeth is the best guarantee for good masticatory efficiency with increasing age.

The dentition is a part of the orofacial system. It has important functions such as speech and chewing. However the question is whether masticatory function declines when more loss of teeth occurs. In this article attention is given to the masticatory process and the masticatory performance in relation to complete or partial tooth loss and to the question to which requirements the dental prosthesis has to come up in relation to the food intake and the masticatory performance.

The impact of loss of teeth on chewing ability was investigated in three groups of patients. One group already had missing teeth replaced by partial dentures, which were taken out during the tests. This group was taken as not being adapted to chew without a complete dentition. A second group had their missing teeth not replaced by partial dentures. During the test they were considered adapted to chew without a complete dentition. A third group had a complete natural dentition and they acted as control group. Tests were carried out regarding chewing ability and swallowing threshold. In addition, a clinical examination was carried out. It was found that the loss of molars significantly reduced chewing performance. Moreover the number of chewing-strokes before swallowing the food-bolus and the mean of the particle size at the point of swallowing were increased. Loss of molars resulted in less positive feelings concerning chewing. Both groups of persons with missing molars showed a similar chewing performance. The group of not adapted patients felt on average more negative about their chewing ability and they indicated more changes in daily activities because of missing teeth.

By means of panoramic radiographs of 76 patients we investigated the development and eruption of lower premolars following premature loss of their deciduous predecessor. Following extraction of deciduous molars the mineralization of the bicuspids was accelerated. The eruption of the respective bicuspids took place earlier than expected. During eruption root length was shorter than usual for that stage of development. Although the bicuspids reached occlusion earlier than normal, root mineralization continued to normal length.