Question 1

Relining and Rebasing RPDs: When?

Accepted Answer

Especially distal extension RPDs have a special need for maintenance, mainly relining or rebasing because of the continuing alveolar bone resorption. If a distal extension RPD loses the support of soft tissues and begins to move, damage to the abutments and soft tissues are unavoidable. Therefore, a distal extension RPD should be relined periodically to maintain its close adaptation to the underlying soft tissues and to avoid causing subsequent trauma to the oral cavity.

Question 2

Q: How do you understand the terms Relining & Rebasing?

Accepted Answer

_Relining_ is the refitting of the denture base by adding a small amount of new material to the fitting surface of the denture base to make the denture fit more accurately on the underlying tissue. _Rebasing_ is the replacement of the entire denture base with new material, without changing the occlusal relation of the denture. Relining removable partial dentures is a common occurrence in many dental practices; however, rebasing is not done as often.

Question 3

Relining and rebasing of RPDs: Definitions according to the Glossary of Prosthodontic Terms:

Accepted Answer

_Reline_: the procedure used to resurface the intaglio of a removable dental prosthesis with new base material, thus producing an accurate adaptation to the denture foundation area _Rebase_: the laboratory process of replacing the entire denture base material on an existing prosthesis NOTE: The artificial teeth may also have to be replaced during the rebasing process!

Question 4

Relining and rebasing of RPDs: Differentiation between the two terms:

Accepted Answer

In case of loss of the supporting tissues, the most convenient treatment is the relining of the RPD. Rebasing is needed when the denture base has some fractures, cracks, or has become irreparably discolored. It is very important to differentiate the meanings of relining and rebasing to avoid confusion as they are frequently mixed up. In both situations, a new impression is necessary. However, it is also possible to complete the relining in a chairside intraoral technique, which is not possible in the rebasing procedures.

Question 5

To determine the need for relining or rebasing an RPD, the following evaluations may be undertaken:

Accepted Answer

1. Place a thin portion of irreversible hydrocolloid or elastomeric impression material to the intaglio surface of the RPD base; seat the RPD in the mouth and wait until the impression material sets. Remove the RPD and inspect for the thickness of the impression material. If it is more than 2 mm thick, make a reline. 2. Seat the RPD in the mouth and apply a seating pressure on the most posterior part of the RPD and inspect the indirect retainers. If the indirect retainers lift more than 2 mm, make a reline. 3. Instruct the patient to close the mouth in centric occlusion and inspect for the posterior contacts of the RPDs. If a loss of occlusal contacts on the posterior teeth is inspected, place a wax on the occluding surfaces and instruct the patient to close. Inspect the wax, and if the occlusal contact between artificial dentition is lacking, make a reline together with an occlusal correction.

Question 6

Residual ridge resorption Is unpredictable Is multifactorial Is irreversible Q: What other factors may affect the rate of residual ridge resorption?

Accepted Answer

1. _Individual_: age, gender, duration of edentulousness 2. _Local_: hygiene, history of periodontal disease or other pathology 3. _Metabolic_: calcium and phosphate 4. _Systemic_: osteoporosis, osteopenia, smoking, alcohol consumption, diet 5. _Prosthetic_: use of removable denture, accuracy of fit, duration of use

Question 7

Primary criteria for an RPD reline:

Accepted Answer

1. Good chemical bond 2. Satisfactory strength 3. No warping or dimensional change in the prosthesis 4. Speed of the procedure

Question 8

Direct-reline: Advantage of the direct technique:

Accepted Answer

The advantage of the direct technique is time and cost savings, whereas, the advantage of the indirect technique is a harder, denser, and more completely cured resin reline compared with direct reline materials.

Question 9

Direct-reline: Materials used:

Accepted Answer

The materials used for direct-reline procedures are more porous and flexible and less color stable. Additionally, although both the heat-cured PMMA used in the indirect technique and the direct-reline materials contain some residual monomer, which may be cytotoxic to particular patients, direct-reline materials comprise a greater risk because of less polymerization. In general, the indirect method has been preferred because of the above- mentioned advantages, but no long-term studies have compared the outcomes of the two methods. Before starting the relining procedures, the oral mucosa should be returned to an acceptable state of health that may require a period of function without the RPD or using the RPD with a tissue conditioner after relief of the RPD in the effected regions.

Question 10

Relining Tooth-Supported RPDs:

Accepted Answer

The need of relining the tooth-supported RPDs is not common because the tissue changes that arise underneath the denture bases do not distress the support of the RPDs. Since the abutments rather than the residual ridges absorb the occlusal loads, tooth-supported RPDs have the minimum amount of residual ridge resorption. It is much more practical to use an intraoral chairside technique when a tooth- supported RPD is to be relined. Because making an impression requires that the RPD be flasked and processed, the occlusal vertical dimension may be increased and the RPD may be distorted during laboratory procedures. It is not feasible to take these risks for such an easy procedure if the RPD has not to be rebased.

Question 11

Q: Can you think of any reason why relining of tooth supported RPDs may be indicated?

Accepted Answer

Indications for relining tooth supported RPDs: 1. Relining procedures are performed only for hygienic or esthetic reasons. 2. Food trapping between denture base and mucosa: risk of caries, periodontal disease 3. Patient reported discomfort because of gapping between denture base and mucosa 4. Aesthetics!

Question 12

Indications for rebasing tooth supported RPDs:

Accepted Answer

1. Anterior teeth need to be replaced as well, or rearranged 2. Anterior denture base needs to be replaced for aesthetic reasons 3. Anterior denture base has become defective

Question 13

Relining Distal Extension RPDs:

Accepted Answer

Distal extension RPDs require correction by relining or rebasing much more often than tooth- supported RPDs because the majority of the support is from the underlying soft tissues and residual ridges and more occlusal loads are directed to the residual ridges through the prosthesis. The patient should be informed that a distal extension RPD requires periodic examination and relining due to maintaining the health of the abutment teeth and the residual ridges before the treatment. This information has an important role in defending the rights of the clinician to charge the patient in periodic visits.

Question 14

Indications for relining tooth & mucosa supported RPDs: Q: What will happen if the free end saddle is not well supported?

Accepted Answer

The RPD will ‘sink’ towards the tissues in function Denture teeth will not be in occlusion any more Trauma of the denture bearing tissues; pain and/or discomfort Increased rate of residual ridge resorption Tilting forces applied on distal abutment tooth Excessive forces applied on the other teeth (occlusal load unevenly distributed) Anterior components of the RPD will tend to ‘lift’ away from the tissues This may further damage soft and hard tissues

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Relining and Rebasing the Removable Partial Denture: Flashcards

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