Equipoise is balance of force design. It protects, preserves and strengthens abutment teeth while directing all masticatory forces down the long axis of the abutment tooth. Equipoise was designed by Roach in 1930. Roach concepts on Equipoise were later modified by European and North American dentists giving us similar clasps concepts with other names. It is designed for use on the palatal / lingual surface of the abutment.
The design creates forces along the long axis of the abutment tooth with passive retention. All clasping in this Removable Partial Denture System is designed intra-arch. In Equipoise Class II Lever design, an element of support, and contention and retention for the distal buccal surface of the abutment must be placed. The Class II lever design has the rest(fulcrum) opposite of the retentive tip of the clasp (resistance arm) and the denture base (the effort arm).
Principles of Equipoise Removable Partial Denture
1. Minimum strain to the abutment.
2. Greater retention.
3. Improved esthetics.
Criteria fulfilled by Equipoise Design of Removable Partial Denture
5. Built in Permanence
Overdentures are complete dentures that are partially supported by natural teeth or dental implants. The objective of overdentures is to slow down the resorption of residual ridge which inevitably follows extraction of the teeth. In addition to the support and retention that can be gained from retained roots or implants, overdentures are superior to conventional complete dentures in biting force, chewing efficiency and force discrimination.
Indications for Overdentures
At least on tooth can be retained.
Adequate oral hygiene.
The prognosis for wearing complete dentures is poor.
The remaining teeth would be more severely damaged by other type of treatment.
Copy denture can be a modified or a duplicate copy from the existing denture of the patient. It preserves the surface of the existing denture while allowing modifications on the tissue side and occlusal surfaces of a complete denture. As a patient’s adaptive potential decreases with age, the maintenance of the shape of the original polished surface results in less adjustment of the supproting musculature required.
Indications for Copy Dentures
Upper and lower complete dentures which have been satisfactory but are now loose.
Patient with a history of denture problems where it may be advantageous to make controlled modifications in the copy denture of the most successful previous dentures.
Previous immediate dentures which require replacing after bone resorption.
Spare set of dentures.
Spoon Design Removable Partial Denture is a simple acrylic denture to replace one or two anterior teeth usually the lateral incisor. It derives its support and retention from the ridge and palate.
Indications for Spoon Design Upper Denture
Is is indicated for patients who suffered the loss of one anterior tooth. There should be a wide well formed palate with sufficient anterior clearance between the lower incisors and the ridge – also known as denture space.
Cobalt Chromium Removable Partial Denture can be tooth supported or tooth and tissue supported prosthesis. It incorporates both strength and rigidity to resist deformation from highly complex stress fields during normal masticatory movements.
Removable partial denture treatment has six phases:
- Education of patient.
- Diagnosis, treatment planning, design, treatment sequencing and mouth preparation.
- Support for distal extension denture bases.
- Establishment and verification of occlusal relations and tooth arrangements.
- Initial placement procedures.
- Periodic recall.
Indications for Cobalt Chromium Removable Partial Denture
It is indicated for patients with good hygiene and high motivation to accept dental prosthesis. There must be a distribution of abutment teeth which have good bone support.
Removable Acrylic Partial Denture is a mucosa borne denture that conforms to a specific design to ensure gingival health. The construction of the denture follows the usual prosthetic technique. An accurate impression is required to establish the point contact between the teeth.
Indications for Acrylic Removable Partial Denture
It is indicated when replacement of missing teeth is necessary for short period of time such as for the sake of appearance while tissue is healing. Other indications include:
- space maintenance
- reestablishment of occlusal relationships.
- to condition teeth and residual ridges.
- interim restoration during treatment.
- to condition the patient for wearing a denture.