Hindawi Publishing Corporation International Journal of Dentistry Volume 2010, Article ID 807850, 7 pages doi:10.1155/2010/807850 Clinical Study Occlusion and Temporomandibular Function among Subjects with Mandibular Distal Extension Removable Partial Dentures N. H. J. Creugers, D. J. Witter, A. Van ’t Spijker, A. E. Gerritsen, and C. M. Kreulen Department of Oral Function and Prosthetic Dentistry, College of Dental Science, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500HB Nijmegen, The Netherlands Correspondence should be addressed to N. H. J. Creugers, N.Creugers@dent.umcn.nl Received 14 April 2010; Accepted 17 June 2010 Academic Editor: Francesco Carinci Copyright © 2010 N. H. J. Creugers et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Objective. To quantify eﬀects on occlusion and temporomandibular function of mandibular distal extension removable partial dentures in shortened dental arches. Methods. Subjects wearing mandibular extension removable partial dentures (n = 25) were compared with subjects with shortened dental arches without extension (n = 74) and with subjects who had worn a mandibular extension removable partial denture in the past (n = 19). Subjects with complete dentitions (n = 72) were controls. Data were collected at baseline and at 3-, 6-, and 9-year observations. Results. Occlusal activity in terms of reported awareness of bruxism and occlusal tooth wear of lower anterior teeth did not diﬀer signiﬁcantly between the groups. In contrast, occlusal tooth wear of premolars in shortened dental arches with or without extension dentures was signiﬁcantly higher than in the controls. Diﬀerences amongst groups with respect to signs and symptoms related to temporomandibular disorders were not found. Occlusal support of the dentures did not inﬂuence anterior spatial relationship. Occlusal contacts of the denture teeth decreased from 70% for second premolars via 50% for ﬁrst molars, to 30% for second molars. Conclusions. Mandibular distal extension removable partial dentures in moderate shortened dental arches had no eﬀects on occlusion and temporomandibular function. 1. Introduction Extension of moderate shortened dental arches (3 to 5 posterior occluding units) is still a controversial issue. The most cited arguments for extending shortened dental arches are improvement of chewing function and rehabilitation of posterior support. Regarding chewing ability, only about 10% of subjects with moderate shortened dental arches reported complaints on chewing function for hard foods [1, 2]. Chewing capacity can be expressed in a scale running from maximum chewing capacity as in complete dentitions to minimum capacity in subjects with full dentures. The chewing capacity of subjects with moderate shortened dental arches is approximately halfway this scale [3]. Moreover, it has been demonstrated that having a moderate shortened dental arch gives no reason for shifts in food selection and does not aﬀect gastrointestinal function dietary [4, 5]. With respect to chewing ability no beneﬁt can be gained from replacing absent teeth unless fewer than three posterior occluding pairs are present [6]. Also the arguments to restore posterior support by distal extension of moderate shortened dental arches remain controversial. It is thought that posterior support prevents or reduces manifestations of the so-called posterior bite collapse. This collapse is accompanied by migrations in the premolar regions, interdental spacing, decrease in ver- tical dimension, changes in temporomandibular condyle position, overeruption of unopposed teeth, and increased vertical overlap and ﬂaring of anterior teeth [7]. Previous studies showed that in moderate shortened dental arches these phenomenons are just limited or even absent. For moderate shortened dental arches without extension, it was concluded that minor occlusal changes appeared to be self-limiting and adaptive in character [8] and that subjects with shortened dental arches had similar prevalence, severity, and ﬂuctuation of signs and symptoms related to