The influence of patients' decisions on treatment planning in restorative dentistry

Literature review of factors influencing treatment planning

Most systematic reviews in dentistry state that more good quality double blind randomized control trials are required, and there is insufficient good quality evidence to recommend one intervention over another.1

Good success and survival rates have been shown for restorations,2^,3 crowns,4 veneers,5^,6 implants,7-9 bridges,9-11 and endodontics.12-14 Most quoted success rates are from data pooled from hospital and university departments or from private practice. These rates form only one important aspect of the treatment planning process. Compromised situations may generally reduce success rates. Time, number of appointments, use of anaesthesia or sedative agents, pain and suffering contribute to which treatment plan is selected. Biological and financial cost-benefit analyses need to be explained to the patient.

Clinical factors

Clinical factors, summarized in Table 1, should be recognized, are well described in standard textbooks, and it is not the purpose of this paper to discuss this aspect of treatment planning.15-17 The summation of the clinical factors allows the dentist to devise possible treatment options to discuss with the patient.

Factors that influence patients' decisions

Patients seek dental treatment for three main reasons:

They are the true judge of whether their treatment is successful or not, so it is imperative that they are happy with it. Their subjective evaluations of a proposed treatment do not always correlate with acceptance of evidence-based recommendations from the literature.18 This evaluation depends on the value patients attribute to a treatment. Aesthetic oral appearances create an impression of better intellect, which drives patients to seek dental treatments with the most aesthetic outcomes.19 Female patients associate darker and decayed teeth with negative personality traits, whereas whitened teeth create positive impressions.20 When females are exposed to images of fashion models from media sources, they perceive their own appearance is worse compared to when unexposed.21 This increased aesthetic awareness can drive patients to request destructive, biologically invasive work in scenarios where appearances could easily and equally be improved, with less risk of morbidity. For example, bleaching and bonding with veneers, or composite additions, may improve aesthetics with the same effect as full coverage crowns, with less tooth destruction and risk of pulp death and pain. A list of factors which influence patients' decisions when considering treatment options in restorative dentistry is summarized in Table 2.

Gilmore et al22 compared the importance patients place on objective evidence-based literature with their dentist's recommendations for treatment. One hundred patients were provided with vignettes containing both research evidence and dentists' recommendations. The results showed where these two sources are not in agreement, then patients place more emphasis on their dentist's recommendation. Men were more confident in their treatment decisions than women. If a dentist recommends a treatment, the patient is 2–21 times more likely to have it done. In those patients who value their oral health, the likelihood of having a treatment is increased up to 10 times. In comparison, the recommendations made by evidence-based literature made no difference to a patient choosing to go ahead with a treatment. When patients are faced with information from research and clinicians, literature-based information has no effect whatsoever on treatment choice. The key determinant of a patient's treatment choice appears to be the dentist's clinical judgement. Trust in the dentist's advice forms the basis of a professional relationship with the patient.

Chapple et al23 have shown that most patients wish to play a collaborative role with their dentist in the decision-making process; with patient and dentist sharing the responsibility equally. They performed a cross-sectional study of 20 patients, each from the University Dental Hospital of Manchester and a dental practice in Cheshire. A Control Preferences Scale was used to identify the roles that patients like to play and feel that they play in the decision-making process. This scale was in the form of a set of sort cards outlining five decision-making roles:

A second set of cards was used to identify the patients' perceived role. Results showed most patients wanted to collaborate equally with their dentist to form their treatment plans. This indicates that patients feel there is no room for paternalistic models of clinician-patient interaction, where dentists simply dictate treatment without allowing for, and actively encouraging, patient input. However, patients' perceived roles in the decision-making process with their current dentists differed, as both cohorts felt that they actually played a passive role. This was especially so in the Hospital cohort who felt that they had very little input in the treatment planning process. This may be because patients feel that they offset differences in their preferred and perceived roles by receiving free treatment. The study showed that patients would like to collaborate more with their dentists and play an equal role in the treatment planning process, but feel that they currently still play a passive role.

Some of the factors influencing patients' decisions in restorative dentistry exist as various entities in healthcare models which have been tested to show the relative importance patients' attribute to them in the clinical decision-making process. Numerous medical healthcare models exist and have been developed over many years to predict patients' decision-making when presented with an intervention or precaution. These models are centred on the assumption that patients weigh up the benefits against cost-effectiveness of proposed treatments.24 Models vary greatly in the range of costs and benefits considered, and also in the specific equation to predict patients' likely decisions. They are useful to describe factors patients consider when faced with treatment options and decision-making, but are limited in their use because no model is entirely accurate or complete. Examples of models used in healthcare which have received empirical support in predicting patients' decisions, and therefore help to plan service delivery and public health initiatives, aid research and audit include:

The health belief model has been most widely adopted in medicine but no model is as accurate when applied to dentistry.28^,29 Oates et al30 developed a dental model addressing patients' decisions to undergo extensive restorative treatment (Figure 2). This model takes into account patients' perceptions of barriers to care, value of treatment, dentist-provider relationship, social influence and critical incidents precipitating treatment. Barriers to care are subdivided into fears and anxieties, costs of treatment, time involved and access to care. Value of treatment is composed of aesthetic value, functional value, self-esteem and health motivation.

To test the model and assess the relative importance patients attribute to each factor, and sub-factor, a 52 question survey was sent to 250 patients who had received restorative dental work at a USA State University Dental School, who had incurred costs in excess of $1500 each.31 The restorative work included crowns, bridges, inlays, onlays, veneers, partial dentures and any related attachments, but excluded endodontic and periodontal treatment. A 77% response rate was achieved and gave insight into which factors patients found relevant in decision-making for their restorative treatment. Results, summarized in Table 3, showed that the likelihood of a certain treatment being chosen by a patient was most influenced by the patient-dentist relationship, where a positive relationship was more likely to result in the patient consenting for treatment. This was followed by barriers to care, strength of cue, value placed upon treatment and, least influential, was social influence. Barriers to care and social influence were found to have an inverse relation to the likelihood of treatment acceptance. The positive aspects of the patient-dentist relationship examined in this study were perceptions of a shared responsibility, friendliness, being encouraged to ask questions and being given enough information to make a good decision.

The results indicated that patients perceive time taken for treatment completion as the most important barrier to care, followed by, access to care, fears and anxieties and costs involved. Perhaps surprisingly, financial costs appear to be the least important factor to patients when they weigh up whether to accept restorative treatment. Health motivation, ie the desire to achieve oral health and a disease-free mouth was found to be the most important value to patients. This was followed by aesthetics, self-esteem and functional value.

This study showed that a good dentist–patient relationship is the most predictive factor for a patient to accept a proposed treatment plan. This is especially so if the dentist involves the patient and allows a collaborative approach to decision-making, engages with them, is friendly and encouraging, and gives sufficient information. The cost of treatment is the least influential factor preventing a patient accepting a treatment, but access to care, eg parking and lifts and time required for treatment, are important.

Quite often, when presented with options for treatment, patients may ask the dentist, ‘What would you do?’. This occasionally puts the dentist in an awkward position, but perhaps the best way to answer this question is to use ‘the Daughter test’.32 This reminds the dentist to stick to prescribing treatment as he or she would for a close, dearly loved one.

Case histories

Case 1: Management of the non-vital restorable tooth (Figures 3–6)

A female accountant, aged 54 years, presented with broken down and root treated LL6 and LL7 (Figures 3, 4) with guarded long-term prognoses. She had an implant-retained fixed bridge opposing these mandibular molar teeth. The five options available were discussed with her:

1. Endodontic re-treatment, cast core and crown.

2. Endodontic re-treatment, direct core and crown.

3. Extraction and implant placement. Immediate and delayed implant placements were discussed.

4. Extraction and denture provision.

5. Extraction and accept the space.

These options were available for each tooth and so a combination of the above options was feasible. The evidence base indicates that implant-retained restorations have the best survival rates out of the available options. However, the patient weighed up these options and decided to pursue option 1: endodontic re-treatment, a cast core and crown on both teeth (Figure 5). This is because she valued keeping her teeth, although she knew they did not have good prognoses. She also did not wish to accept a space as she had a history of being unable to eat on the left side owing to missing teeth in the upper left quadrant. She did not wish to pursue implant surgery at this stage as she thought the teeth could survive longer with repair. She was prepared to accept the cost of repair of the teeth knowing that further costs would be incurred if implants were provided in future.

The range of full-coverage crown options available was then discussed:

Precious metal;

Non-precious metal;

Porcelain fused to metal (PFM);

PFM with metal margin;

PFM with occlusal metal;

All-ceramic.

Out of these options, full coverage metal crowns are thought to have the best survival rates owing to marginal adaptation and least tooth preparation. Occlusal metal coverage with buccal porcelain also reduces the risk of porcelain fracture under occlusal loading. However, the patient did not want any metal to show and chose a PFM crown with occlusal porcelain and metal margin (Figure 6) to provide the best appearance and marginal fit. The risks of porcelain fracture were made clear.

Case 2: Advanced periodontics: maintain tooth or extract and replace (Figures 7–9)

A 52-year-old lady, working as a secretary, complained of poor aesthetic appearance of her maxillary anterior teeth (Figure 7). She felt that the ‘front teeth were dropping’, some back teeth were loose and interdental spacing had appeared. These problems developed over the last few years. Her oral hygiene was fair, she had Basic Periodontal Examination scores of 4 in all sextants and crowns had been placed on UR2 and UR1.

She was diagnosed with generalized chronic periodontitis. There was generalized 40–70% irregular bone loss on a dental panoramic tomogram (DPT) (Figure 8).

The following options to address her aesthetic concerns were discussed:

A. Stabilization of periodontal disease, root-surface debridement under local anaesthetic and:

Further periodontal treatment or maintenance care, depending on the initial response;

A labial soft tissue acrylic veneer;

Crowns on selected anterior teeth;

Porcelain veneers on selected anterior teeth;

Direct composite veneers on selected anterior teeth;

Orthodontics followed by permanent splinting.

B. Extraction of maxillary incisors and:

Replacement with fixed-fixed design conventional bridgework;

Replacement with fixed-fixed design resin-retained bridgework;

Replacement with implants;

Replacement with a partial denture.

C. Dental clearance:

Maxillary dental clearance and complete dentures;

Maxillary and mandibular dental clearance and complete dentures;

The dentures could possibly be followed by dental implant placement and fixed implant bridges or implant overdentures.

A sequential approach to treatment could apply to all of these options.

In this case, in order to close the tooth spaces and replace soft tissue, a removable prosthesis would provide best aesthetics. But denture provision would increase the risk of plaque retention in a periodontally susceptible mouth. Preservation of her own teeth was more important to the patient than the desired aesthetic improvement in this case.

She selected periodontal treatment and maintenance. In view of the severe recession, soft tissue replacement would have been necessary with any form of tooth replacement, using a denture flange or pink porcelain on a fixed prosthesis. Crowns would have been ‘square’ shaped to reduce the interproximal spaces and increased the clinical crown height. Veneers have poor success on bonding to root cementum and UR1 and UR2 were both crowned already at presentation.33 The prognosis for the whole dentition was uncertain.

Case 3: Hypodontia of the anterior maxilla with insufficient labial bone for screw-retained implant restorations (Figures 10–13)

A 23-year old male medical student presented with missing UR2, UR1 and UL2 (Figure 10). These teeth were provisionally replaced by an upper partial acrylic denture. The maxillary lateral teeth were missing and UR1 had been removed following trauma. Now that he had stopped growing, and was a student with some flexibility for time to attend for appointments, he felt it was the best time to seek fixed replacements of his teeth.

On examination, the alveolar ridges were thin and cone beam computed tomography showed labial bone concavities (Figure 11). Therefore, the main options available to him were:

1. Implants with either: (a) an autogenous extra-oral or intra-oral onlay bone graft or; (b) ridge augmentation using Guided Bone Regeneration (GBR) techniques;

2. Resin-retained bridges;

3. Continue with current partial denture.

Other denture options, including a chrome partial prosthesis, were declined by the patient.

Option 1(b) was selected by the patient as he did not wish to have an onlay bone graft from the iliac crest, or intra-oral sites, owing to morbidity from the extra surgery. Though the patient was currently available for appointments, onlay grafting would prolong the treatment time by at least 4 months. He was not keen on hospital admission and wanted the least invasive implant option in order to minimize the impact of treatment on his studies. The benefit of placing a bone graft in the labial concavities would be to ensure that screw-retained restorations could be placed on the implant fixtures. However, an equally aesthetic prosthetic result could be achieved using angled or custom abutments. The advantage of retrievability offered by screw-retained options, involving onlay grafting procedures, was rejected by the patient in this case. Three implant fixtures were placed in the UR2, UR1 and UL2 sites. GBR was performed at the same time. The fixtures were placed in maximum bone volume to maximize primary stability and came through in the bone envelope with a slightly labial inclination (Figure 12). Cement-retained porcelain fused to metal crowns were constructed on a 15° angled abutment on UR2 and custom-made abutments on UR1 and UL2 (Figure 13).

Case 4: Posterior tooth restoration (Figures 14, 15)

A 52-year-old male sales representative presented with a fractured buccal cusp on the UR6 (Figure 14). The options for definitive restoration discussed with the patient were:

Amalgam;

Composite; direct or indirect;

Onlay;

Three-quarter crown;

Full crown.

In this case, a cast metal restoration with cuspal coverage, an onlay or crown, may provide the best long-term restoration success rate. Amalgams in posterior teeth generally show better longevity than composites but the patient chose to have the tooth restored by direct composite.3 This was because he did not wish to have further tooth reduction, saw bonding as a reversible option and wanted an aesthetic result. The financial cost was also low compared to indirect laboratory-made restorations.

Case 5: Post-endodontic treatment restoration (Figures 16–18)

A 33-year-old female teacher had successfully completed endodontic treatment of UR8 (Figures 16, 17) and cast or direct restoration options were discussed. The patient wished to have an amalgam restoration, although the accepted guidance on the restoration of endodontically restored teeth indicated that a cuspal coverage restoration be placed.34

Discussion

These common cases illustrate the many complex clinical decisions dentists make on a daily basis, taking into account clinical and patient factors. Service providers may dictate which treatments are permissible. There has long been a variation in the treatment provided by dentists which relates to the dentist's education, knowledge, experience and confidence.35-37 There are also wide variations between dentists, recognizing relevant features of treatment plans.38 Recently, a standardized classification and prognosis evaluation system has been described which takes into account the condition of the teeth and patient-level factors.39 This system attempts to reduce variation in the treatment dentists provide and increase the number of options offered to patients. However, patients' views are also very variable in what they see as an acceptable treatment, depending on their own values, feelings, understanding and experience. Objective assessments of patients' aspirations and expectations should be made, with attention to detail, whilst open communication is essential for decision-making.40

Summary letters should be written and sent to all patients where operative work is planned outlining the following:

This acts as an aide-mémoire for patients about the treatment they are to receive and how many appointments to expect. The importance of the dentist-patient relationship cannot be underestimated and a positive relationship is most likely to result in a patient consenting for treatment. Patients put a lot of emphasis on dentists' recommendations and, where research and a dentist's view differ, patients generally side with their dentist's approach. However, patients want to play a collaborative role with their dentist in the decision-making process. This is not always observed in a hospital setting, where patients may be prepared to accept treatment without discussion as it is given free of charge, provided in specialist settings, can involve multidisciplinary care and as a result of the ‘halo’ effect of consultants.

Patients may demand elective work that potentially incurs morbidity. No dentist should carry out unreasonable treatment at the request of a patient. A treatment plan that is not evidence-based or agreed with the patient runs the risk of a complaint or, at worst, medico-legal action. However, treatment plans with an element of compromise can be acceptable if, following full discussion with the patient, and taking into account all relevant factors, the benefits outweigh the disadvantages. This is the basis of informed consent.

Conclusion

Treatment planning in restorative dentistry is not an absolute science. Treatment plans should be acceptable to patients and informed consent obtained. Dentists exert considerable influence in this process and should be well informed to do so. Treatment plans based on good scientific research evidence should be clearly presented to patients with a cost-benefit analysis, including the financial and biological costs. On occasion, some compromise can be acceptable as long as all partners are fully informed and there is a good reason for doing so.