Professional Denture Help

"I need a denture – what are my options?"

• Conventional removeable partial dentures
• Precision and semi-precision partial dentures
• Conventional over-denture
• Implant over-denture
• Immediate dentures - what to expect
• Wearing a new denture – what to expect
• Why consider a metal base denture?

• Conventional Removable Partial Dentures

A partial denture is useful for a person missing some teeth, but still having a number of natural teeth.

This device is also called a removable prosthesis, and is a means by which artificial replacement teeth are held in the mouth. The prosthesis is commonly kept in place by means of clasps. These are thin finger-like structures, usually made of a special resilient metal alloy or sometimes plastic, that rest upon and wrap around some remaining natural teeth. Clasps keep the prosthesis securely in place but still allow a person to easily take it out for regular cleaning and proper brushing of remaining natural teeth.

Some reasons for having a partial denture made

Replace missing teeth
Improve ability to chew more naturally
Chew food with confidence
Make it possible to eat certain favorite foods
Maintain a healthier and socially acceptable mouth
Aids in the preservation of remaining natural teeth
Help prevent or treat problems of the TMJ (the jaw joint)
Often improve speech
Helps develop a more pleasing and confident smile
Support the face - - often with a more youthful appearance
Enhance self esteem
An economical way to replace missing teeth
Many times an additional tooth may be added to an existing partial denture if a natural tooth is lost
In most cases crowning teeth is not necessary to fit a partial denture
Partial dentures are usually easy to repair if they are broken

Esthetics and the conventional partial denture

Generally, clasp design is reasonably esthetic, and often it is possible for them not to be seen. However, depending upon partial denture design, which is based on mouth conditions, there may be some show of clasps. Often this is not an appearance problem. However, if avoiding an unacceptable show of clasps would compromise optimal partial denture design, various special attachments may sometimes be employed to do away with conventional clasps. These attachments are more technically complex and often are referred to as precision or semi-precision attachments.

How long will a partial denture last?
Accidents happen, and the mouth is constantly changing. Partial dentures may no longer fit properly, can break or bend or simply wear out. In fact there is nothing made for the mouth that is permanent. Fractured clasps and so forth may often be repaired.

On average, a partial denture may be expected to last about five years. Depending upon circumstances, a certain removable prosthesis can last a shorter or longer time.

How often should a partial denture be checked?
It is best to have a partial denture, as well as the rest of the mouth, checked at six-month intervals. If left uncorrected, small problems can develop into major ones that could cause disease, loss of teeth or necessitate premature prosthesis replacement.

Partial dentures need to be relined
The jaw ridge a partial denture rests upon is constantly changing. It is normal and necessary to regularly modify how a partial contacts the ridge. This maintenance correction is called relining and on average needs to be performed annually for optimum function. However, this is dependent upon how an individual's mouth changes. A licensed dental professional can best advise when a reline is needed, and when a reline will no longer adequately restore proper function.

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• Precision And Semi-Precision Partial Dentures
(Avoiding Conventional Partial Denture Clasps)

Precision and semi-precision partial dentures, like conventional partial dentures, replace missing natural teeth with artificial teeth. However, the means by which they are retained in the mouth is different than a conventional clasp prosthesis. To better understand these partial denture types, it is best to first review the basics of conventional partial denture clasps.

How conventional partial denture clasps function

Most partial dentures are usually kept in place by clasps. These are thin finger-like projections of special resilient metal alloy, or, in certain cases, plastic or plastic-like.

Clasps rest on and around certain remaining natural teeth so that their ends extend into undercut areas below a gentle bulge on the tooth. Sometimes it is necessary to shape a tooth or make a crown for a tooth or teeth in order to develop the right amount and relationship of undercut and bulge for retention.
When a partial denture is placed in the mouth, clasps gently spring over a tooth bulge and rest in a relaxed state within an undercut.
A partial denture is held in place during normal eating, speaking and other activities because clasps resist springing back over tooth bulges.
Clasp resistance to removal is not great enough to prevent a person from comfortably removing their partial denture whenever they choose.

The problem with conventional clasps

Despite numerous successful conventional clasp designs, they do have some drawbacks.

Clasps may at times become visible. Often this is unavoidable and usually is not objectionable. However, for some individuals the show of clasps is simply not acceptable because of personal circumstances and compromised appearance.
Certain partial dentures may function better with retentive means other than conventional clasps.
Remaining natural tooth structures may be inadequate to accommodate conventional clasps. Therefore a crown or crowns may need to be fabricated to correct these deficiencies.

Semi-precision and precision partial dentures - - viable alternatives

Alternatives to conventional clasp partial dentures fall into two categories, both of which have no clasps to show.

Semi-precision partial dentures are retained in the mouth by means of mechanical interlocking components. A specially shaped extension of the partial denture fits into or on to a complementary receiving area or projection of a natural tooth that has been crowned. The components fit snugly and consist of a semi-rigid metal to other surface interface, which may also be metal or some other resilient material such as nylon.

	1.	Semi-precision partial dentures are retained in the mouth by means of mechanical interlocking components. A specially shaped extension of the partial denture fits into or on to a complementary receiving area or projection of a natural tooth that has been crowned. The components fit snugly and consist of a semi-rigid metal to other surface interface, which may also be metal or some other resilient material such as nylon.
	2.	Precision partial dentures are similar to the semi-precision type except that the mechanical interlocking components are manufactured to extremely high tolerances and are held together by precise alignment and a rigid metal to metal frictional interface of components.

Advantages of semi-precision and precision partial dentures

	•	A cosmetically enhanced partial denture as compared to conventional partial dentures
	•	No show of metal clasps
	•	Blends in with the conformity of remaining natural teeth
	•	Functions with a more even pressure on remaining natural teeth than conventional partial dentures

Disadvantages of semi-precision and precision partial dentures

	•	More costly to fabricate
	•	Usually some natural teeth need to be crowned
	•	More difficult to fabricate and adjust
	•	Some components may need periodic replacement

Which type of partial denture is best?

Every patient has unique oral health needs that are best determined by a licensed dental professional after a thorough examination.

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• Conventional Over-Denture
A conventional over-denture rests over some healthy natural tooth roots. This approach, was first reported in 1861. To understand this method it is necessary to review some facts.

An overview of alveolar ridge dynamics

	•	Maintaining a denture on the jaw bone ridge (called alveolar ridge) is essential to preventing it from becoming loose during eating, speaking and other activities.
	•	Preserving the alveolar ridge facilitates denture stability.
	•	The body tends to conserve energy and nutrients by maintaining only structures with apparent immediate value. A typical example is the bulk reduction of a broken leg held immobile by a full-leg cast for a month or more.
	•	The body "recognizes" the only one purpose for alveolar bone is to hold tooth roots.
	•	Alveolar bone no longer supporting a tooth root is removed, or literally dissolved away by the body. This is called resorption or simply shrinkage.
	•	Resorption progresses at varying rates in the same person at different times and at different rates between different people. Resorption progresses rapidly within the first year of loosing a tooth after which time the rate progresses at a slower pace.

Preserving alveolar ridge bone

From this overview, if the maximum amount of alveolar ridge is to be maintained then preserving the maximum number of periodontally healthy tooth roots should achieve that end.

Preserving the sensation of having teeth

Studies demonstrate that even though only roots are preserved, and they are covered by a denture, a patient still has sensory input sensations similar to that experienced with teeth, as opposed to individuals with conventional dentures and no preserved roots. Over-denture patients also appear to have a more natural perceived directional sense in their chewing activities. In other words, many patients relate that they still feel like they have teeth - - a positive comment.

Underlying philosophy of the conventional over-denture

If a patient is treatment planned to have a denture, and the roots of some remaining teeth are supported in healthy alveolar bone - - then a conventional over-denture is a viable consideration.

However, only a licensed dental professional can determine if a conventional over-denture is a suitable consideration for a certain person, after a comprehensive examination.

Some characteristics of a conventional over-denture

	•	Most of a tooth crown (that part of the tooth above the gums) is removed. This often necessitates root canal therapy if not already done.
	•	Remaining tooth, projecting above the gum, is rounded and usually covered with a similarly shaped artificial crown-like covering.
	•	Various configurations and extensions may be built onto some retained roots. In those cases, that portion of the denture overlying these configurations is modified to contain attachments that clip onto a framework or receive the individual extensions. In addition to preserving alveolar bone and sensory input, the denture is securely held in place, but may be comfortably and easily removed for cleaning.

Advantages of a conventional over-denture

	•	Feels more like having teeth
	•	More retentive in many cases
	•	Helps reduce shrinkage of surrounding bone
	•	Reduces pressure to portions of the alveolar ridge
	•	Positive psychological advantage of still having teeth

Disadvantages of a conventional over-denture

	•	Scrupulous oral hygiene is essential in order prevent decay and gum disease.
	•	The over-denture may feel bulkier than a conventional denture.
	•	Frequent maintenance examinations are necessary.
	•	Generally this is a more expensive approach than a conventional denture.

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• Implant Over-Denture

An implant over-denture connects to cylinder-like configurations (called implants) that have been surgically implanted into jaw bone.

The denture appears like a traditional prosthesis. However, that part of the denture overlying implants is modified to retain various semi-rigid attachments that receive implant extensions projecting above the gum. This arrangement helps keep a denture securely in place while eating, speaking and during other oral activities, but still allows easy self-removal of the denture for cleaning purposes.

There are two phases to this process. The first is a surgical phase consisting of two stages, and the second is a prosthetic phase (making the implant denture).

The surgical phase

Surgical insertion stage

	•	Implants are completely inserted into precise preparations in jaw bone. While there are various implant configurations, they are essentially cylindrical in shape and made of pure titanium metal. After implants are inserted into jaw bone, gum tissue over the implant is closed with sutures in most cases.
	•	While a minimum of two implants may be inserted for an acceptable outcome, a person may be treatment planned to receive three or more - - depending upon individual needs and anatomical limitations. More implants will give additional support and retention to the implant denture.

Healing and surgical exposure stage

	•	During healing, an existing or temporary denture may continue to be worn after adjustments have been made to adapt to the surgerized site. If the existing denture cannot be altered sufficiently, a provisional prosthesis should be fabricated.
	•	Implants are left undisturbed beneath gum tissue for at least several months as determined by the dental professional. During this time bone reorganizes and grows around the implant surface, anchoring it securely into the jaw (this is called osseointegration).
		At the end of the healing stage, the top of the implant is exposed by removing gum tissue directly over it. An extension that is then screwed into the exposed implant projects slightly above the gum tissue.
	•	After adjustments, an existing denture can be worn over an implant extension while the gum heals. However, the denture must be reshaped to conform to surgical site contours in order to avoid unnecessary pressure areas on the newly surgerized site.

The prosthetic phase (making the implant denture)

	•	A precision superstructure is fabricated that is screwed into the implant extensions. This superstructure may have various interface configurations ranging from interconnecting metal bars to specially shaped singular extensions.
	•	A denture is fabricated with special provisions on the inside surface to receive various types of attachments (interlocks). Depending on the attachment, they interact in various ways with the superstructure. For example, a metal or plastic attachment may clip onto metal superstructure bars, a nylon receptacle may receive a specially configured implant extension, and so forth.
	•	The attachment/superstructure configuration helps to securely maintain a denture while eating and speaking, and still allows a person to comfortably and easily remove the prosthesis for cleaning purposes.

Essential maintenance needs

As might be expected, exemplary oral hygiene is essential to helping prevent the development of disease around implants that could cause their failure.

Implants, superstructure, attachments and the over-denture must be checked and professionally maintained by a licensed dental professional on a regular basis. Attachments often need periodic adjustment or replacement due to wear.

While the implant over-denture approach is complex and expensive, the value received by an individual usually far exceeds monetary considerations.

How long will implant over-dentures last?
An implant may last for a lifetime (current reports show many implants lasting twenty years) or deteriorate in a few years - - many factors are involved that reduce the life expectancy of implants, such as oral hygiene, general health, habits such as smoking, grinding, and so forth. The superstructure or implant extensions may need to be replaced after five years. Depending on the implant system used, some parts may need to be replaced annually, or sooner, because of wear or deterioration. These time frames are generalities. The dental profession continues to strive for long-term durability.

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• Immediate Dentures - - What To Expect
Immediate dentures are placed in the mouth directly after remaining teeth are extracted. This approach is utilized when a person does not want to be without any teeth for several months while extraction tooth sockets heal and a denture is fabricated.

A two-denture process
Optimally an immediate denture is the first denture of a two-denture process and should be considered as a temporary interim prosthesis until a second refined and esthetically enhanced denture may be constructed after healing.

First of two dentures stage

	•	Usually most or all of the back teeth are removed and extraction sites allowed to heal a minimum of six-weeks or more, depending upon an individual's healing rate.
	•	After adequate healing an immediate denture is fabricated.
	•	Remaining teeth are extracted and the immediate denture is placed in the mouth. Wearing a denture immediately over extractions is normally no more uncomfortable than the extractions alone. Discomfort is managed with proper anesthesia and pain medication. The immediate denture acts like a Band Aid
	•	Generally the dental professional does not remove an immediate denture until the day after surgery. Surgery is checked and denture adjustments are made as necessary.
	•	The immediate denture will gradually become loose because of bone shrinkage as the jaw continues to heal. Provisional liners are placed in the loosening denture to help hold it in place better during healing. Adhesives also maintain the denture in place as it becomes looser. If the immediate denture becomes too loose during this healing period of several months, it may be necessary to reline multiple times.

Second of two dentures stage

	•	After adequate healing has occurred, a second refined denture is fabricated. This denture allows the dental professional to now artistically position teeth in an optimal and enhanced esthetic relationship, which was not possible with an immediate denture. It is now also possible to establish better functional relationships of the jaws.
	•	Approximately six months after the second denture is delivered, it will likely need to be relined to compensate for continuing jaw shrinkage. After this reline, a patient usually needs annual relines to accommodate a continually shrinking jaw. The frequency of relines is an individual matter unique to each patient and is best determined by a licensed dental professional after a thorough periodic examination that should occur at six-month intervals.

Modified approaches

	•	It is possible to extract all the back and front teeth at one time and insert an immediate denture. However, such an approach is problematic and is generally discouraged unless the patient has no other alternatives.
	•	All teeth may be extracted with no interim denture while the jaws heal and a denture is fabricated. This is generally a more economical approach, but an individual would be without teeth for several months.

Advantages of an immediate denture

	•	A person is not without teeth for any extended period of time.
	•	The immediate denture acts as a "bandage" while boney tooth sockets are healing after tooth extractions.

Disadvantages of an immediate denture

	•	A second refined and esthetically enhanced denture is necessary soon after the immediate denture.
	•	While the cost of an immediate denture is generally about the same as a conventional denture, the second denture needs to be fabricated soon after the immediate denture. Therefore, a person would be experiencing the additional cost of the second denture sooner.

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• Wearing A New Denture - - What To Expect

Complete dentures are less than perfect replacements for natural teeth. However, they have proven to be effective for countless individuals and can be comfortable to wear - -

if a person has reasonable expectations and recognizes that there will definitely be an adaptation period.

It is important to understand that "showing off" with a new denture often ends in an unpleasant and embarrassing experience. One must first practice with their new prosthesis and learn what limitations and compensations need to be considered.

The old adage of "learn to walk before you run" certainly applies to the successful, secure and comfortable wearing of dentures.

Some factors to consider when wearing a new denture

This is not an exhaustive review of new denture learning considerations. However, these are common areas of concern. If a person has a unique question or problem, they should always contact their dental professional, for advice and direction.

	•	Full feeling: When new dentures are first placed in the mouth they frequently feel fuller, and it may not seem like there is enough room for the tongue. When a person has been without teeth for a period of time, the inside of the cheeks and tongue can become reversibly slightly fuller. When a new denture is first inserted, this slight fullness may feel enormous. In actual fact it is not, and the full feeling will usually go away very shortly if an individual does not dwell on the sensation. Previously unsupported sunken facial structures and muscles will usually be supported with a new denture to a normal position. These facial tissues adapt rapidly to their regained normal positioning and will feel less strained and subtler shortly. A more youthful appearance results in many cases.
	•	Phonetic difficulty: When a person is used to producing speech sounds without teeth or with an old denture that has no longer preserved proper jaw relationships, they generally have adapted their speech in such a way as to accommodate these abnormal conditions. However, when correct jaw relationships and contours are established again with a new denture, there may be some difficulty producing certain speech sounds clearly, and teeth might even click together in some instances. This is temporary. If an individual makes an effort to speak slowly and clearly, pronouncing words very precisely, the tongue and other muscles will quickly adapt to produce clear speech. It is often useful to read a book or newspaper out loud, carefully pronouncing each word precisely.
	•	Sore spots and irritations may develop as a new denture settles-in. This may require some adjustment to the body of the denture, and, more often, careful adjustment of the bite resolves these types of problems. At times the jaws may feel tired and soreness can develop. Taking dentures out to rest the mouth for a time frequently helps resolve these problems.
	•	Chewing patterns will need to be developed over several weeks starting by chewing with small pieces of soft food and gradually increasing the firmness over several weeks. Generally food should be chewed on both sides of the mouth at the same time. Front teeth are considered primarily for esthetics and speech and to a lesser degree for function. Food is not bitten off with the front teeth efficiently, rather the bolus of food should be held by the dentures, near the corners of the mouth, and torn off by rotating the hand holding food in a downward motion. This will increase chewing efficiency and reduce irregular denture rocking. A denture patient needs to take control and keep a positive attitude for optimal results.

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• Why Consider A Metal Based Denture

A metal based denture is one in which a portion of the denture body is made of a substantial metal casting rather than all plastic (acrylic resin). This procedure is usually done on the lower denture.

There are two types

	•	Standard metal based denture: The metal base portion of the denture is in direct contact with underlying supporting tissues. The base is fabricated from a special medical grade alloy that is hypoallergenic and very biocompatible with tissues. Generally tissues in contact with this type of material are very healthy in appearance.
	•	Modified metal based denture: The metal base portion of the denture is not in direct contact with underlying supporting tissues. A soft or hard plastic liner may be interposed between the metal and supporting tissues. A soft liner is generally preferred to hard plastic since it is more comfortable to wear; however, the soft liner usually should be replaced on an annual basis.

The rational for a metal base

	•	Facilitates avoiding disruptive forces: Sometimes it is necessary to construct a very narrow denture in order to avoid any structures that would lossen the prosthesis, such as muscles flexing, and so forth. In addition, necessary surgical procedures to reposition a muscle attachment (called frenum) can sometimes be avoided with these narrow type dentures. However such narrow dentures are weak and tend to break quite easily when fabricated just from plastic. A metal base provides the needed strength to design a very narrow denture in order to follow the confines of a patient's lower resorbed alveolar ridge (the remaining bony ridge). In addition, the metal base provides long-term dimensional stability and strength that is not enjoyed with an all plastic denture base.
	•	Provides a more natural feeling: Added weight of the metal base provides a more natural perception for many patients. Many patients prefer the additional weight on the lower jaw. A private study measured the actual weight of cadaver jaw ridges and teeth that would normally be lost after the extraction of teeth and associated natural shrinkage of jaw bone, and it was found that the weight of these tissues closely approximated the weight of a metal base. Therefore, it is likely that the more natural feeling perceived by persons wearing metal based dentures is probably real rather than imagined. The additional weight of a metal base also contributes to lower denture stability by causing the denture to settle down onto a jaw ridge.

Advantages

	•	Very biocompatible and hypoallergenic with healthy appearing supporting tissues
	•	May include a soft liner
	•	Can be relined easily
	•	Provides added strength for easily broken narrow dentures
	•	Facilitates fabrication of stable narrow based dentures that are designed to avoid contact with disrupting muscle forces
	•	Sometimes facilitates avoiding surgical procedures to reposition frenum
	•	Patients perceive a more natural feeling from the added weight
	•	Weight may contribute to additional denture stability
	•	Dimensionally very stable when compared to all plastic based dentures during fabrication and over time.

Disadvantages

	•	Generally difficult to reline standard metal based dentures; modified metal based dentures (described earlier above) are easier to reline.
	•	More costly to fabricate

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