Tooth Replacements From the Patient’s Perspective

Tooth loss is a permanent condition in that the natural order has been disrupted, and in this sense it is much like a chronic medical condition. Like hypertension and diabetes, two medical conditions that are not reversible and that require medical management to monitor care to ensure appropriate response over time, tooth replacement prostheses must be managed to ensure appropriate response over time.

The term management suggests a focus on meeting needs that may change over time. These needs may be expected or unexpected. Expected outcomes are those that accompany the common clinical course for a type of prosthesis that is related to the tooth-tissue response. This biological toll response is heavily influenced by the type of prosthesis chosen. In addition, various needs due to prosthesis degradation and related to expected time-to-retreatment concerns of life expectancy are seen. Unexpected needs are those that might involve factors related to our control of manipulations (such as tissue damage or abuse, material design flaws, or prosthesis design) or to those out of our control (such as parafunction or accidental trauma).

With this in mind, it is helpful to consider how we approach educating our patients about management of missing teeth. Most often, a typical sequence is used to discuss tooth replacement options with patients: dental implant–supported prostheses, fixed prostheses, and, finally, removable partial dentures. When removable partial dentures are suggested, they are seldom described in the detail in which fixed or implant prostheses are described, as they generally are considered less like teeth and not as desirable a replacement. The desirability of a prosthesis is important to consider, and because removable partial dentures (RPDs) are less like teeth than other replacements, it is important to recognize what this suggests from the patient’s perspective.

Patients’ experiences have involved natural teeth, and their expectations of replacements would best be described within this context. The order with which we provide replacement prosthesis options for consideration is likely developed on the basis of numerous factors, including the following: we may believe we know what’s best for patients, our practice style may not include removable options, we may not have had good experience with removable prostheses and this lessens our confidence in their use, or RPDs do not match our practice resources.

Although these are important factors, the reason to include RPDs in the discussion is related to identifying whether such a prosthesis is viable, and, if so, whether it is the best option for the patient. We discover this only by interacting with our patients regarding their expectations and understanding their capacity to benefit from options of management that have trade-offs unique to each type of prosthesis.

Shared Decision Making

When patients are given information regarding their oral health status, which includes disease and functional deficits, as well as the means to address both, what do they need to hear? To achieve a state of oral health, they need to recognize behavioral issues related to plaque control, so that once active disease is controlled, they have an understanding that best ensures future health. For tooth replacement decisions, complex trade-offs in care choice are often required. The “shared decision making” approach addresses the need to fully inform patients about risks and benefits of care, and ensures that the patient’s values and preferences play a prominent role in the ultimate decision.

It is recognized that patients vary in their desire to participate in such decisions, thus our active inquiry is required to engage them in discussion. This becomes especially important when elective care, which involves potentially high-burden, costly options with highly variable maintenance requirements, is considered.

When patients wish to participate, it is our responsibility to provide them with specific and sufficient information that they can use to decide between treatment options. Specific information ideally comes from our own practice outcomes, in that such information provides effectiveness information and is provider specific. Sufficient information describes exactly what aspects of care are important to the overall decision. Ultimately, it is our role to help patients consider important differences between different prosthesis types.

What then defines important differences? Multiple outcomes combine to describe the overall impact of prosthetic care for all patients. These include technical outcomes, physical outcomes, esthetic outcomes, various maintenance needs, initial and future costs, and even physiologic outcomes that suggest to what extent prostheses “feel” like teeth.

When tooth replacement prostheses are considered from a patient’s perspective, it can be seen that the desire is to replace teeth that serve functional and social roles in everyday life. In considering how well various types of prostheses may meet patients’ specific needs, it is helpful to note what features of the original dentition—the gold standard, in this instance—we strive to duplicate in the replacement. Although it is common to find that existing oral conditions do not easily allow complete restoration to the state of a fully dentate patient, considering the respective strengths and weaknesses of the prosthodontic options (compared with this “gold standard”) helps in identification of realistic expectations.

In this text, the focus will be on a type of replacement prosthesis for patients with some, but not all, missing teeth. The replacement prosthesis ideally should provide function and a level of comfort as equivalent as possible to normal dentition. In achieving this, stability while chewing is a primary focus of attention, and we should strive to determine what is required to ensure it. If the prosthesis will be visible during casual speaking, smiling, and/or laughing, it is obvious that the replacement should look as natural as the surrounding environment. In summary, tooth replacement prostheses should provide a combination of several features of natural teeth: socially acceptable in appearance, comfortable and stable in function, and maintainable throughout their serviceable lifetime at a reasonable cost.

Education of Patient

The term patient education is described in Mosby’s Dental Dictionary as “the process of informing a patient about a health matter to secure informed consent, patient cooperation, and a high level of patient compliance.”

The dentist and the patient share responsibility for the ultimate success of a removable partial denture. It is folly to assume that a patient will have an understanding of the benefits of a removable partial denture unless he or she is so informed. It is also unlikely that the patient will have the knowledge to avoid misuse of the restoration or will be able to provide the required oral care and maintenance procedures to ensure the success of the partial denture unless he or she is adequately advised.

The finest biologically oriented removable partial denture is often doomed to limited success if the patient fails to exercise proper oral hygiene habits or ignores recall appointments. Preservation of the oral structures, one of the primary objectives of prosthodontic treatment, will be compromised without the patient’s cooperation in oral hygiene and regular maintenance visits.

Patient education should begin at the initial contact with the patient and should continue throughout treatment. This educational procedure is especially important when the treatment plan and prognosis are discussed with the patient. Limitations imposed on the success of treatment through failure of the patient to accept responsibility must be explained before definitive treatment is undertaken. A patient usually will not retain all the information presented in the oral educational instructions. For this reason, patients should be given written suggestions to reinforce the oral presentations.

Diagnosis, Treatment Planning, Design, Treatment Sequencing, and Mouth Preparation

Treatment planning and design begin with thorough medical and dental histories. The complete oral examination must include both clinical and radiographic interpretation of (1) caries, (2) the condition of existing restorations, (3) periodontal conditions, (4) responses of teeth (especially abutment teeth) and residual ridges to previous stress, and (5) the vitality of remaining teeth. In addition, evaluation of the occlusal plane, the arch form, and the occlusal relations of the remaining teeth must be meticulously accomplished by clinical visual evaluation and diagnostic mounting. After a complete diagnostic examination has been accomplished and a removable partial denture has been selected as the treatment of choice, a treatment plan is sequenced and a partial denture design is developed in accordance with available support.

The dental cast surveyor (Figure 2-2) is an absolute necessity in any dental office in which patients are being treated with removable partial dentures. The surveyor is instrumental in diagnosing and guiding the appropriate tooth preparation and verifying that the mouth preparation has been performed correctly. There is no more reason to justify its omission from a dentist’s armamentarium than there is to ignore the need for roentgenographic equipment, the mouth mirror and explorer, or the periodontal probe used for diagnostic purposes.

Figure 2-2 Dental cast surveyor facilitates the design of a removable partial denture. It is an instrument by which parallelism or lack of parallelism of abutment teeth and other oral structures, on a stone cast, can be determined (magnified view shows parallel guide plane surface). Use of the surveyor is discussed in later chapters.

Several moderately priced surveyors that adequately accomplish the diagnostic procedures necessary for designing the partial denture are available. In many dental offices, this most important phase of dental diagnosis is delegated to the commercial dental laboratory because this invaluable diagnostic tool is absent, or because the dentist feels inexperienced or is apathetic. This situation places the technician in the role of diagnostician. Any clinical treatment based on the diagnosis of the technician remains the responsibility of the dentist. This makes no more sense than relying on the technician to interpret radiographs and to render a diagnosis.

After treatment planning, a predetermined sequence of mouth preparations can be performed with a definite goal in mind. It is mandatory that the treatment plan be reviewed to ensure that the mouth preparation necessary to accommodate the removable partial denture design has been properly sequenced. Mouth preparations, in the appropriate sequence, should be oriented toward the goal of providing adequate support, stability, retention, and a harmonious occlusion for the partial denture. Placing a crown or restoring a tooth out of sequence may result in the need to restore teeth that were not planned for restoration, or it may necessitate remaking a restoration or even seriously jeopardizing the success of the removable partial denture. Through the aid of diagnostic casts on which the tentative design of the partial denture has been outlined and the mouth preparations have been indicated in colored pencil, occlusal adjustments, abutment restorations, and abutment modifications can be accomplished.

Support for Distal Extension Denture Bases

The third of the six phases in the treatment of a patient with a partial denture involves obtaining adequate support for distal extension bases. Therefore it does not apply to tooth-supported removable partial dentures. With the latter, support comes entirely from the abutment teeth through the use of rests.

For the distal extension partial denture, however, a base made to fit the anatomic ridge form does not provide adequate support under occlusal loading (Figure 2-3). Neither does it provide for maximum border extension nor accurate border detail. Therefore some type of corrected impression is necessary. This may be accomplished by several means, any of which satisfy the requirements for support of any distal extension partial denture base.

Figure 2-3 A, Occlusal view of a cast from a preliminary impression, which produced an anatomic ridge form (left), and an altered cast of the same ridge showing a functional or supportive form (right). The altered cast impression selectively placed pressure on the buccal shelf region, which is the primary stress-bearing area of the mandibular posterior residual ridge. B, Buccal view of anatomic ridge form. C, Buccal view of functional or supportive ridge form. Note that the supportive form of the ridge clearly delineates the extent of coverage available for a denture base and is most different from the anatomic form when the mucosa is easily displaced.

Foremost is the requirement that certain soft tissue in the primary supporting area should be recorded or related under some loading, so that the base may be made to fit the form of the ridge when under function. This provides support and ensures maintenance of that support for the longest possible time. This requirement makes the distal extension partial denture unique in that support from the tissue underlying the distal extension base must be made as equal to and compatible with the tooth support as possible.

A complete denture is entirely tissue supported, and the entire denture can move toward the tissue under function. In contrast, any movement of a partial denture base is inevitably a rotational movement that, if toward the tissue, may result in undesirable torquing forces to the abutment teeth and loss of planned occlusal contacts. Therefore every effort must be made to provide the best possible support for the distal extension base to minimize these forces.

Usually no single impression technique can adequately record the anatomic form of the teeth and adjacent structures and at the same time record the supporting form of the mandibular edentulous ridge. A method should be used that can record these tissues in their supporting form or in a supporting relationship to the rest of the denture (see Figure 2-3). This may be accomplished by one of several methods that will be discussed in Chapter 16.

Establishment and Verification of Occlusal Relations and Tooth Arrangements

Whether the partial denture is tooth supported or has one or more distal extension bases, the recording and verification of occlusal relationships and tooth arrangement are important steps in the construction of a partial denture. For the tooth-supported partial denture, ridge form is of less significance than it is for the tooth- and tissue-supported prosthesis because the ridge is not called on to support the prosthesis. For the distal extension base, however, jaw relation records should be made only after the best possible support is obtained for the denture base. This necessitates the making of a base or bases that will provide the same support as the finished denture. Therefore the final jaw relations should not be recorded until after the denture framework has been returned to the dentist, the fit of the framework to the abutment teeth and opposing occlusion has been verified and corrected, and a corrected impression has been made. Then a new resin base or a corrected base must be used to record jaw relations.

Occlusal records for a removable partial denture may be made by the various methods described in Chapter 17.

Initial Placement Procedures

The fifth phase of treatment occurs when the patient is given possession of the removable prosthesis. Inevitably it seems that minute changes in the planned occlusal relationships occur during processing of the dentures. Not only must occlusal harmony be ensured before the patient is given possession of the dentures, but the processed bases must be reasonably perfected to fit the basal seats. It must be ascertained that the patient understands the suggestions and recommendations given by the dentist for care of the dentures and oral structures and understands about expectations (based on the “Shared Decision Making” discussion) in the adjustment phases and the use of restorations. These facets of treatment are discussed in detail in Chapter 20.

Periodic Recall

Initial placement and adjustment of the prosthesis certainly is not the end of treatment for the partially edentulous patient. Periodic reevaluation of the patient is critical for early recognition of changes in oral structures to allow steps to be taken to maintain oral health. These examinations must monitor the condition of the oral tissue, the response to tooth restorations, the prosthesis, the patient’s acceptance, and the patient’s commitment to maintain oral hygiene. Although a 6-month recall period is adequate for most patients, more frequent evaluation may be required for some. Chapter 20 contains some suggestions concerning this sixth phase of treatment.