6 Absence of striking diﬀerences in occlusal wear in the anterior teeth is in line with the so-called “anterior guidance” phenomenon. In mutually protected occlusions, which are most common in natural dentitions [24], the anterior teeth guide excursions. It seems that this anterior guidance is acting alike in shortened dental arches as well as in complete dentitions. This similar acting also can be denoted from our ﬁndings on vertical and horizontal overlap, presenting no relevant diﬀerences amongst the dental groups. The latter is not surprising as increased vertical and horizontal overlap— as a symptoms of a posterior bite collapse—is not a matter of excessive loading on maxillary anterior teeth due to reduced posterior support or loss of vertical dimension, rather than resulting from advanced periodontal disease or habits of lips and tongue [25]. Our results regarding reported awareness of bruxism and occlusal tooth wear did not substantiate a possible triggering eﬀect from the distal extension prostheses with respect to temporomandibular related signs and symptoms. In general, the distal extension prostheses in moderate shortened dental arches seem to have no positive eﬀects with respect to the investigated occlusal aspects. As such they do not contribute to clinically relevant posterior occlusal support. Restored occlusal support in terms of occlusal contacts by these dentures is just a fraction of that of natural teeth [23], which is conﬁrmed in the present study. The ﬁndings of this longitudinal study are in line with those of other studies, suggesting preclusion of making distal extension removable partial dentures in moderate shortened dental arches [6, 26]. If extension of shortened dental arches is considered, evidence indicates that (resin-bonded) cantilever ﬁxed partial dentures is the ﬁrst treatment option rather than distal extension removable partial dentures [27]. 5. Conclusions Within the limitations of this study it can be concluded that subjects with moderate shortened dental arches with or with- out mandibular distal extension removable partial dentures as compared to subjects with complete dentitions had (1)similar frequencies for reported awareness of bruxism; (2)similar occlusal wear of lower anterior teeth; in con- trast, premolars had signiﬁcantly more occlusal tooth wear; (3)similar frequencies of signs and symptoms related to temporomandibular dysfunction; (4)no clinically relevant diﬀerences of anterior relation- ships in terms of vertical and horizontal overlap. 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