CPD article Continued »
challenge for us to treat effectively. The most significant factor is
the loss of the upper anterior bone, which then dictates the other changes which occur (see Fig 2). It is also suggested that excessive
mented by Shen2 in ı989. They examined ı50 consecutive complete maxillary edentulous patients, a group including complete upper and lower denture wearers, upper against lower complete dentition, upper against unilateral lower tooth loss and upper against bilateral posterior tooth loss. They found:
2. The incidence of CS in maxil- lary denture opposed by natural anterior mandibular teeth was 24 per cent.
The numbers were not great but
the trend certainly exists. Like Kelly before, Shen also found
that the presence or absence of a removable lower partial denture (RPD) has little or no effect on preventing the problem. This article looks to explain how
the situation occurs, what can be done to prevent it in the first place and, once realised, the options for managing it. The timeline for tooth loss for
heavily restored dentitions and especially periodontal patients, seems to follow a similar pattern: loss of lower molars, upper molars, upper interiors and lastly lower anteriors. From both perspectives this makes sense: the posterior teeth have the most complicated anatomy, are the most challenging to restore and for
56 Scottish Dental magazine Fig 4 Over-erupted lowers and non-visible uppers
occlusal forces are a significant contributing factor. Due to the flabby ridge which develops over the premaxillae, there is no stable vertical stop for the denture. Without lower posteriors, the upper denture easily tips, losing the seal on the post-dam. One of the theories about development of the enlarged tuberosities is negative pressure from the tipping of the denture. Of course, disuse over eruption of upper molars prior to extraction could also be a likely cause. The prevalence of CS was docu-
Typical appearance of CS patient Fig 1
Fig 2
Upper flabby anterior ridge, enlarged tuberosities and excessive use of fixative
Fig 3 Shortened dental arch
1. The incidence of CS in the maxil- lary complete denture population was 7 per cent
Fig 5
Extrusion of the lower anteriors and pneumatisation of the sinuses
Fig 6
Guide plane prep for hybrid Maryland
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