Sobredentaduras

Dent Clin N Am 48 (2004) 585–601

Implant-retained maxillary overdentures
Steven E. Eckert, DDS, MS*, Alan B. Carr, DMD, MS
Mayo Medical School, 200 First Street Southwest, Rochester, MN 55905, USA

Patients seek tooth replacement to address issues related to comfort, function, or esthetics. As patients experience the loss of teeth the dentist’s ability to provide restorations that meettheir desires diminish. In response to this situation dentists have diligently sought to establish new approaches to address the edentulous or partially edentulous condition [1–3]. The dentist’s reduced ability to meet the patient’s needs relates to the valuable service that natural teeth provide when dental prostheses are made. Natural teeth support dental prostheses from forces toward theedentulous ridges, they retain prostheses from forces that tend to dislodge the prosthesis, and they stabilize prostheses to resist all other non-axial forces [4]. These functions—support, retention and stability—are provided by teeth in combination with the soft and hard tissues of the residual ridges in removable prosthodontics. When the teeth are lost, the patient may experience difficulty as the residualstructures are substituted for the natural dentition. Rather than having clasps, edentulous patients rely on ridges, buccal shelves, and hard palates for retention and support. Peripheral seal becomes critical when complete denture retention is considered. Although the vertical projections of the residual ridges may provide stability, the patient certainly experiences a reduction in stabilitycompared to that provided by guiding planes in the natural dentition. Thus the transition from the dentate state to partially or complete edentulism is a path that is fraught with concern on the part of the patient. The patient’s emphasis may change from function, a relatively objective problem, to the more subjective concerns of esthetics and comfort. This transition from objective [5,6] tosubjective emphasis creates an everincreasing challenge for the dentist to satisfy the patient’s requests. Classically, an overdenture has been used for patients who find themselves in this transition from dentate to edentulous [7,8]. By retaining a few
* Corresponding author. E-mail address: seeckert@mayo.edu (S.E. Eckert). 0011-8532/04/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved.doi:10.1016/j.cden.2004.03.004

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S.E. Eckert, A.B. Carr / Dent Clin N Am 48 (2004) 585–601

strategically positioned roots, the dentist is able to address the patient’s desires better. Perhaps it is the psychosocial advantages of tooth preservation (even if it is only a portion of a tooth) that makes the overdenture a viable ´ consideration [6]. Retained roots allow the patient to avoid thecliched stigma of being long in the tooth, thereby retaining a connection with youth [9–11]. The overdenture carries with it some complex dental problems, however. Retention of natural tooth roots offers a number of potential benefits. These roots seem to slow the process of residual ridge resorption. They provide the patient with better proprioception through the retention of the periodontalligament fibers [9,12–15]. If retentive components are incorporated in the overdenture abutment teeth, denture retention increases profoundly. The natural tooth roots support the prosthesis, and the increased height of the alveolus surrounding the root, in conjunction with the root itself, enhances stability. The benefits obtained from the retention of natural tooth roots used to support an overdentureseem to be numerous. Unfortunately a few factors may make the use of natural tooth roots less appealing. Teeth remain susceptible to caries (Fig. 1) and periodontal disease [16–20]. To establish a favorable crown-to-root ratio, root canal therapy may be necessary before crown resection. Retentive components, which may be intracoronal or extracoronal, generally demand the use of a cast restoration...