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Why overdentures?

by: Stefan Holst

The clinical application of multi-unit, implant-supported restorations in edentulous jaws has proven to be a predictable long-term treatment option.

Why Overdentures?

In this propitious context, implantretained removable solutions provide a number of interesting advantages for select patients.

Despite the fact that patients considering implant treatment tend to contemplate a fixed restoration first, numerous studies have proven that implant-retained overdentures can also significantly improve masticatory function and, at the same time, fulfill patients’ expectations and demands.

An awareness of the need to restore esthetic appearance is not limited to the partially edentulous. Indeed, it is of great importance to fully edentulous patients as well.

The most conspicuous esthetic impairment these patients have to face affects extra-oral appearances. Substantial atrophy of the alveolar ridge requires extensive support of the peri-oral musculature if facial harmony is to be reestablished.

While this can be achieved technically with a fixed restoration, the resulting design of the prosthesis may significantly impair hygiene accessibility. It is important to differentiate between two different types of removable restorations. The implantretained, mucosa-supported overdenture is mostly supported by two interforaminal implants with various anchoring mechanisms such as round or Dolder Bars, ball or magnetic, or other extracoronal attachments, such as Locators.

An alternative to the resilient treatment modality can be found in the implant-supported removable prosthesis, which is a rigidly an- Why Overdentures? Implant-retained overdentures – a prosthetic solution for the 21st century chored prostheses purely supported by implants (four or more fixtures). The implant-supported removable prosthesis is stabilized on extended (CAD/CAM-milled) bars, which prevent rotational movements of the prosthesis.

The advantage of this retention and support design is that the restoration is comparable to a fixed prosthesis. It provides for a stable occlusal plane and prosthesis position when functional forces are applied.

Factors to consider 

Repair options and maintenance needs are additional factors that need to be taken into consideration when decisions are being made about the design and retention mechanism of a superstructure. The most frequently reported technical complication identified for implantretained, mucosa-supported restorations is loosening of the retentive mechanism (e.g., wear of matrices) requiring the replacement of components.

However, the introduction of CAD/CAM-milled, high-precision bar elements for implant-supported removable prostheses has resulted in a significant reduction in the need for post-insertion maintenance. This also holds true for the rigid anchoring of implant overdentures by telescopic attachments. Clinical studies have demonstrated high implant success rates concomitant with only a minor degree of prosthodontic maintenance effort.

In general, both fixed and fixedremovable implant restorations are viable treatment options for edentulous patients. Clinical long-term outcome is comparable if patientspecific characteristics are taken into account during treatment planning and execution.

Decisive factors for either solution include the patient’s age and expressed expectations, the amount of missing hard and soft tissue, the manual skills of the patient and his or her financial situation.

Removable implant-retained overdenture – The pros

  • Re-establishing facial harmony through ideal support of peri-oral musculature
  • Simple hygiene maintenance for the patient (accessibility of intra-oral retentive elements and extra-oral cleaning of the denture)
  • Cost-efficient treatment solution without compromising maximum precision of fit and material quality when utilizing milled titanium bars
  • No need for removal of retaining structure (bar) for hygiene recall appointments
  • Setting of retentive forces can be adjusted to patient demands/capabilities (low friction — maximum friction)
  • Reduced number of implants
  • Fast and easy repair and long-term adjustment potential
  • Transfer of an implant-supported removable prosthesis to an implant-retained mucosa-supported overdenture if manualskills for hygiene maintenance diminish
     

Removable implant-retained overdenture – The cons

  • Patient’s demands and expectations for a fixed solution on dental implants
  • Renewal of plastic/metallic attachment matrices in the implantretained mucosa-supported overdenture
  • Potential psychological impact
  • Technical demands to manufacture frameworks for implantsupported removable prosthesis
  • Space required for primary and secondary support structures

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