How long do removable partial dentures last? -

Reasons why a partial might need to be replaced. / Statistics about service and longevity from dental research.

While a removable partial denture can be a very cost-effective way to replace multiple missing teeth, before spending money for one you might want to have an idea of how long it should last. This page answers that question.

Partial denture longevity, by prosthesis type.

Clearly an appliance's type, design and materials used in fabricating it will all have an impact on how long it can be expected to last. And for this reason we have divided the information on this page into the following categories: 1) cast-metal partials, 2) acrylic partials and 3) flexible acrylic partials.

  • The first half of this page explains each kind of prosthesis and outlines reasons why each type tends to fail.
  • The lower half cites statistics and findings from dental literature about partial denture problem rates and expected life spans, once again organized according to prosthesis type.

Removable partial dentures -

In contrast to complete dentures, partials are dental prostheses that replace one or more missing teeth on a dental arch (upper or lower), yet at least some natural teeth remain.

There are three basic types of construction: cast metal and plastic, plastic and wire, and all-plastic. And each type has it's own expected longevity.

1) Cast partial dentures -

Construction.

These appliances consist of an extensive cast metal framework on which plastic simulated gum tissue and teeth are then attached.

  • Aspects of the framework lie embedded within the plastic portions of the appliance so to give them strength.
  • The cast framework is designed with clasps that grasp around selected natural teeth so to help anchor the appliance.

Overall, this is generally considered to be the preferred type of removable partial denture.

Factors affecting cast partial longevity.
  • The durability of the plastic components of a cast partial will affect its length of service. Fortunately, repair or replacement of these plastic components (flanges, saddles or teeth) is possible and commonplace.
  • The way the clasps of a cast-metal partial grasp around their natural teeth is very precise (more so than with any other type of partial). And this means that how long an appliance will last is very dependent upon how well this relationship is maintained.

    Any factor that alters it (tooth loss, tooth decay, placing new or replacement dental restorations) can seriously compromise the partial's ability to provide service. Also, clasp damage or breakage frequently cannot be satisfactorily repaired.

  • As with all types of dentures, the fit of a partial over its underlying jawbone will tend to change over time (although with some appliance designs this may be a less critical factor than with others). Performing a reline can typically renew this fit and therefore extend the life of the prosthesis.

> How long can you expect a cast partial to last? - Projections / Statistics

2) Acrylic partial dentures -

Construction.

With this type of partial, the bulk of the appliance consists of plastic simulated gum tissue and teeth. Depending on its purpose and design, it may or may not have wrought-wire clasps (as opposed to cast-metal ones) that grasp around selected teeth so to help anchor it in place.

Generally speaking, this is considered to be a less desirable, or just temporary, alternative to a cast partial.

Factors affecting acrylic partial longevity.
  • As compared to cast-metal ones, the tooth-clasp relationship of wrought-wire clasps is less precise (a disadvantage). However the ease with which they can be adjusted makes it easier to maintain a satisfactory appliance fit over the long term (like in the case where a filling has had to be replaced).
  • Just like with other types of prostheses, the durability of the plastics involved can be a limiting factor. Since there is no underlying metal framework, a cast partial could be considered to be the stronger alternative.
  • Damaged, lost or broken plastic components can typically be replaced easily. And additional teeth and clasps can be added as is needed. Also, acrylic partials can be relined. All of these possibilities can help to extend the life span of an existing appliance.
  • It must be stated that generally speaking acrylic partials tend to be more damaging to natural teeth (possibly substantially so) than cast partials, thus shortening the appliance's effective lifespan due to tooth loss (see below).

> How long can you expect an acrylic partial denture to last? - Projections / Statistics

3) Flexible acrylic partials (Valplast®)

Construction.

This type of appliance is made entirely out of a special plastic whose resilient, flexible nature allows that it can even be fashioned into clasps for the partial.

Generally speaking, flexible acrylic partials can be considered to be a more esthetic, possibly more comfortable to wear, version of standard acrylic ones.

Factors affecting flexible acrylic partial longevity.
  • Just as with other types of partials, the durability of the plastic components of a flexible partial (base, clasps, teeth) will affect its length of service.

    Relining or the repair or replacement of plastic components (breakage, tooth loss) is possible but possibly easier to accomplish with standard acrylic partials (see below).

  • Just like with standard acrylic ones, flexible partials tend to cause damage to neighboring natural teeth over the long term.

> How long can you expect a Valplast® partial denture to last? - Projections / Statistics


Statistics about how long removable partial dentures can last.

The following conclusions and estimates about partial longevity are drawn from published dental literature and research.

1) Cast partial dentures.

How long can they last?

Vermeulen (1996) evaluated 886 cast partials (worn by 748 patients). At 5 years 75% of the appliances were still being worn, at 10 years 50%.

Primary reasons for cast partial failure.

Beyond those general issues discussed below (plastic component breakage, tooth loss, general wear and tear, fit changes), cast partials have some unique concerns that can affect how long they might last.

a) Complications with adjacent natural teeth -

Potential problems.

  1. Any part of a partial denture (any kind) that lies against natural teeth creates a semi protected haven for dental plaque accumulation. And if the partial is not taken out regularly and this plaque removed, the formation of tooth decay is a distinct possibility. If it occurs, filling placement or possibly even tooth extraction will be required.
  2. A generally positive factor associated with wearing a cast partial is that it's able to pass the chewing forces placed on it onto the teeth on which it clasps and rests. (This design helps to prevent the gum recession problem discussed below.) However, exposure to these forces can result in tooth or dental restoration damage. If either occurs, a new dental restoration will need to be placed.

Tooth loss, or any event that changes the shape of a tooth that a cast partial clasps onto (like when a new dental restoration is placed), has the potential to significantly alter its fit, possibly even making it unwearable.

Risk statistics.

  • The Vermeulen (1996) study mentioned above determined that at 5 years 60% of cases required some type of repair of adjacent natural teeth, at 10 years 80%.
  • Frank (1998) quizzed patients who had had new mandibular (lower) cast partials placed within the last 5 years. 1/4 of respondents reported that their appliance had caused a problem with their natural teeth.
b) Cast partial breakage -

While the cast metal framework of this type of partial gives it greater strength than its acrylic counterparts discussed below, metal fracture is possible.

Vermeulen (1996) determined a failure rate of 10 to 20% at 5 years and 27 to 44% at 10 years due to metal framework breakage.

c) What should you expect?

A literature review by Tong (2012) concluded that the most likely types of cast partial complications are:

  • Clasp failure - Unlike wire clasps on acrylic partials, if a cast-metal clasp breaks it likely cannot be repaired satisfactorily.
  • Artificial tooth loss - Typically an easy repair.
  • Changes with natural teeth - The need for cavity repair or treatment for gum disease may create a situation that significantly affects the fit or function of the appliance, implying that practicing proper oral home care is an important factor in cast partial survival.

Less likely to occur are:

  • Loss of a natural tooth supporting the partial.
  • Non-repairable fracture of the partial's metal framework.

2) Acrylic partial dentures.

How long can they last?
  • Schwass (2013) cites a publication by Walmsley (2003) that suggests that acrylic partials have an expected life span of only 6 to 12 months.
  • However, the Schwass paper itself reports anecdotally that a time frame of up to 5 years might be expected for "optimal function."

Generally speaking it seems that this type of appliance is best suited to interim or transitional usage. In terms of clinical longevity (survival of the appliance and associated natural teeth), it's likely that most dentists would consider a cast partial to make the superior choice.

Primary reasons for acrylic partial failure.
  • Appliance breakage - Unlike with cast partial dentures, acrylic ones have no internal metal framework. Over time, breakage is likely to occur in areas where circumstances dictate that the partial must be thin or narrow.

    As discussed above for complete dentures, repair can't be expected to restore the appliance to its original full strength. Re-fracturing in the repaired location is not uncommon.

  • Damage to natural teeth - Unlike cast partials whose design allows them to transfer a large degree of chewing forces onto the patient's natural teeth, acrylic ones tend to direct them onto the gum tissue that lies underneath.

    Over time, this tends to cause gum line recession ("stripping") on the adjacent natural teeth, quite possibly leading to their eventual loss. This complication is a major advantage of choosing a cast partial and a primary reason not to choose an acrylic one.

  • The additional issues discussed above for complete dentures (general wear and tear, tooth loss, fit changes, need to reline) apply to acrylic partials too.

3) Flexible acrylic partial dentures.

How long can they last?

We couldn't locate a source that gave an estimate of how long flexible acrylic partials last. Schwass (2013) states that they should not be considered suitable for long-term wear.

In general terms, a study by Takabayashi (2010) reported that flexible dental acrylics (including Valplast®) showed good strength and elasticity characteristics, which led to the conclusion that they offered the expectation of reasonable appliance longevity.

Our conjecture would be that their expected usefulness likely lies on the same order as standard acrylic partials (see above).

Primary reasons for flexible acrylic partial failure.
  • Takabayashi (2010) found that flexible acrylics (including Valplast®) tended to pick up staining from highly colored foods more so than conventional acrylics. Staining could limit the acceptable life span of an appliance.
  • Just as discussed with standard acrylic partials above, the problem of gum stripping (recession) around adjacent natural teeth tends to occur with flexible plastics too (Schwass 2013). This can lead to tooth loss, resulting in an inability to continue wearing the prosthesis.
  • The additional issues discussed above for complete dentures (general wear and tear, fit changes) would apply to flexible acrylic partials too.

While not necessarily a longevity issue, flexible acrylics differ from standard dental ones. And the repair options they offer may be more limited.

Additionally, if repair or a reline is required your appliance may need to be sent to a specialized dental laboratory for service, which may or may not be available in your immediate local area (thus affecting turn-around time).

4) General partial denture complications.

All types of dentures, both partial and complete, are somewhat similar in their construction and therefore tend to experience many of the same types of failures. The list below describes many of the types of problems that can occur. We discuss each of them in more detail on our full denture longevity page.

a) Lost teeth / Plastic breakage

Darbar (1994) [page references] determined that the most frequently experienced type of denture damage was tooth loss (33% of all repairs for full and partial appliances combined) followed by denture base fracture (damage of the pink plastic portion of the prosthesis).

Repair, and therefore extension of a damaged partial's life span, is frequently possible and even commonplace.

How long can a repair last?

Minor repairs, like replacing a single tooth, can be quite successful. However at the other extreme, while it may be possible to patch large cracks or reattach large sections that have broken off, doing so is unlikely to restore the partial to its original strength.

Appliance replacement may make the better (more predictable, lasting) plan. As an alternative, rebasing the partial (replacing the vast majority of its pink plastic portion) may produce a satisfactory result.

b) General wear and tear.

It's the nature of the materials from which partials are made that they will ultimately deteriorate to the point where the appliance is no longer functionally or esthetically acceptable. This might include tooth wear or denture base deterioration and staining.

c) Natural jaw changes.

Over time it's normal and natural that the size and shape of the jawbone on which a partial rests will undergo change. But since the shape of an appliance's plastic does not, its fit will no longer be ideal. The degree to which this is a problem will depend on the design of the partial (for instance, the number of missing teeth and their location).

In many cases a reline or rebase procedure may be able to restore the appliance to acceptable standards and therefore extend its service.

 

 
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