Palatal Lift Prosthesis - Palatal Lift Prosthesis Retention

Palatal Lift Prosthesis Retention

Because a mechanically displaced soft palate imparts enough force upon a palatal lift prosthesis to dislodge it, dentoalveolar anatomy must be considered prior to the fabrication of a palatal lift prosthesis. Although no algorithm regarding a requisite number of teeth exists for the retention of a palatal lift prosthesis, the possession of a full complement of healthy maxillary teeth offers more assurance of adequate retention than any other factor. While palatal lift prostheses can be retained by patients exhibiting maxillary partial edentulism, partially edentulous patients without posterior maxillary teeth suitable for the receipt of prosthetic clasps also known as direct retainers enjoy less retentive predictability than patients with maxillary posterior teeth. Similarly, partially edentulous patients missing anterior maxillary teeth lack the stability and retention afforded by anterior portions of the palatal lift prosthesis called indirect retainers that appose the lingual aspects of anterior maxillary teeth. Alternatively, patients missing enough teeth to compromise the predictable retention of a palatal lift prosthesis may become candidates for the fabrication of a palatal lift prosthesis with the placement of endosseous titanium implants and abutments designed to serve as retentive elements in partially edentulous and edentulous patients.

Interim Palatal Lift Prostheses Retentive Clasp Assembly

Retentive clasp assemblies responsible for securing interim palatal lift prostheses often benefit from the development of exaggerated retentive undercuts. Such undercuts can be bilaterally added to the most posterior dental abutments by bonding a bulk of composite resin to the buccal surface of the proposed retainers if they are adult teeth and the surfaces to which the composite resin is to be added are not restored with metallic or ceramic restorative material. When providing supplemental retentive undercuts for interim palatal lift prostheses to be retained by primary teeth or teeth whose buccal surfaces have been replaced by metallic or ceramic restorative material, the placement of orthodontic bands that harbor large buccal orthodontic brackets can serve as an alternative to the placement of composite resin.

Interim palatal lift prostheses retentive clasps that engage undercuts formed with composite resin or orthodontic brackets are fashioned from custom bent orthodontic wire that is embedded in the polymethylmethacrylate component of the prosthesis. The orthodontic wire extends from the polymethylmethacrylate to engage the gingival aspect of the composite resin or orthodontic bracket serving to provide the prosthesis’ retentive undercut. If the orthodontic wire clasp terminated at its approximation with the dental abutment undercut it engages as do conventional removable partial denture clasps, the interim palatal lift prosthesis could be difficult to insert and remove. Thus, the orthodontic wire clasps used to retain interim palatal lift prostheses are sometimes extended in a mesial direction up to two mesiodistal tooth diameters. Clasps designed in this fashion can be flexed laterally by patients or their caregivers to facilitate the insertion and removal of the interim palatal lift prosthesis.

Buccal view of an interim palatal lift prosthesis master cast with an orthodontic wire clasp bent to engage an orthodontic bracket affixed to tooth number 15 Buccal view of an interim palatal lift prosthesis master cast with an orthodontic wire clasp bent to engage composite resin affixed to tooth number 15 Palatal lift prosthesis clasp assembly engaging composite resin on a second maxillary molar The pharyngeal extension of a palatal lift prosthesis responsible for elevating the soft palate

Definitive Palatal Lift Prostheses Retentive Clasp Assembly

Definitive palatal lift prosthesis clasp assemblies are not unlike those designed for the retention of removable partial dentures. The clasps arise as extensions of a cast metallic alloy prosthetic component termed a major connector that engages the hard palatal mucosa and the lingual surfaces of some or all of the maxillary teeth. Cast definitive palatal lift prosthesis clasps engage dental abutment surfaces harboring what typically represent 0.01 or 0.02 inch undercuts responsible for prosthetic retention. Alternatively, custom bent wrought wire clasps can be soldered to the cast metallic alloy component of the definitive palatal lift prosthesis from which they extend to engage the undercuts responsible for prosthetic retention. Wrought wire definitive palatal lift prosthesis clasps have an advantage over cast metallic definitive palatal lift prosthesis clasps by virtue of their relative resistance to work hardening that can contribute to the fracturing of cast clasps.