The tooth, the whole tooth and nothing but the tooth

Transcription

1 The tooth, the whole tooth and nothing but the tooth Should a tooth be saved or replaced with an implant? Tony Druttman discusses the factors that may help with the decision making process CPD Aims and objections This clinical article aims to discuss the factors that may help with the decision making process between dental implants and endodontics. Expected outcomes Correctly answering the questions on page 33, worth one hour of verifiable CPD, will demonstrate your understand the factors as to whether a tooth should be saved or replaced with an implant. There are many situations when a tooth has suffered the ravages of wear, decay and dentistry and the time comes when complicated and expensive procedures are required to maintain the tooth as a healthy, functional and esthetic unit of the dentition. Consideration may have to be given to the option of extraction and placement of an implant as an alternative to these procedures. There is no doubt that dental implants have been one of the most important developments in the field of dentistry in recent years and they are the first choice option for replacement of missing teeth. However, where a compromised tooth is still present in the mouth, its retention often involves endodontic treatment if the pulp is either compromised or does not have long-term viability. The choice between retention and replacement with an implant is not always straightforward and can be complicated by a number of factors, both local and systemic, relating to the patient as well as the operator. The purpose of this article is to discuss factors that may be relevant in the decision making process. Any clinical decision should be based on the evidence in the literature. The relative success rates of implants and Dr Tony Druttman M.Sc., B.Ch.D., B.Sc. is a registered specialist in endodontics. He maintains two practices limited to endodontics in the West End of London and in the heart of the City of London. He is a past president of the British Endodontic Society and is a visiting teacher in endodontics at the Eastman Dental Institute. He has lectured both in the UK and abroad. He can be contacted via drutt@ endo.uk.com or 1 Figure 1: Failing implant endodontics need to be evaluated and if one treatment modality is likely to be more successful than the other then all else being equal the more predictable option would be preferable. It is important to have a clear definition of what is meant by success. Implant success The success of an implant requires that: It successfully integrates with the bone There is no mobility Cervical bone loss is less than 0.2mm per year after the first year in function No peri-implant radiolucency The design allows for an esthetic result (Smith and Zarb, 1989) Endodontic success Successful endodontic treatment is defined as: The prevention or healing of periradicular periodontitis The retention of the tooth in symptom free function. The outcome criteria have been defined as the following: Healed clinically and radiographically normal Healing clinically normal with a reducing radiolucency Disease persistent radiolucency with or without clinical normalcy Functional residual radiolucency (reduced) with clinical normalcy (Friedman, 2002). 14 ENDODONTIC PRACTICE FEBRUARY 2010

2 Figure 2a: Pre-operative Figure 2b: Postoperative 2a 2b Figure 2c: Eight-month review Figure 2d: Three-year review 2c 2d Success rates The terms survival and success have been used somewhat interchangeably in the implant literature and this has led to some confusion (Iqbal and Kim, 2007). It is not enough for a tooth or implant to still be in place after a pre-determined length of time for the case to be considered a success. Many of the studies quoting implant success actually report implant survival and only monitor those that have successfully integrated. Survival does not necessarily equate with success as an implant exposed to infection may not become mobile until the disease state is very advanced (Figure 1) (Listgarten, 1997). There are very few studies that incorporate figures for implants that have failed to integrate. However, what can be gleaned from the literature is that the long-term implant success/survival rates are quoted to be above 90% (Noack et al, 1999; Naert et al, 2002). The American Dental Association Council on Scientific Affairs reported a mean survival rate for single tooth implants to be as high as 97% from 10 studies involving more than 1,400 implants (ADA, 2004). As with dental implants, it is important to monitor endodontically treated teeth over a period of time as the healing process may take up to four or five years to complete (Figure 2a-d). Interestingly, a Scandinavian study that reviewed teeth radiographically over a year period found a significantly improved success rate compared with the same teeth reviewed 10 years earlier (Fristad et al, 2004). It does beg the question: at what point should we consider the treatment to have either failed or to be successful in the absence of clinical signs or symptoms? The situation is further complicated by the advent of cone beam computerized tomography (CBCT), which can give far more accurate radiographic information than a periapical radiograph. This is likely to reveal the presence of incomplete healing in the cancellous bone, where periapical radiographs show complete healing of the cortical plate. The recommendations of the European Society of Endodontology (ESE) to monitor teeth up to four years may have to be reconsidered in the future and teeth may have to be monitored over a considerably longer period of time when the use of CBCT becomes more readily available. Increased use of CBCT will also undoubtedly improve our diagnostic skills by helping clinicians to be able to identify those cases that are doomed to fail more clearly. This will, in turn, increase the success rate of endodontic treatment. There have been many papers published over the last 80 years on the success rates of endodontically treated teeth, and as with the implant literature, the distinction between success and survival has not always been clear. Because of a lack of standardization in study design, comparison of the data is of limited value. Success rates have varied considerably and without careful analysis, a review is ineffective and misleading. The best evidence suggests that where there has been no evidence of apical periodontitis the success rates of initial treatment are 92-97% (Sjogren et al, 1990; Friedman, 2002; Horsted-Binslev and Lovschall, 2002; Gesi and Bengenholtz, 2003). Where there has been evidence of apical periodontitis, the success rates are reduced by 10-20% (Friedman, 2002; Sjorgren et al, 1990). The figures are further complicated by definition. If a reduction in the size of the radiolucency is considered a success as well as elimination of radiolucency, then an increase in success rate of 10% has been reported (Ng et al, 2007). Survival analysis taken from American insurance records of 1.4 million root treatments has shown 97% retention of endodontically treated teeth over an eight year period (Salerhabi and Rotstein, 2004). Similar epidemiological studies have yielded comparable results (Lazarski et al, 2001; Chen et al, 2007). ENDODONTIC PRACTICE FEBRUARY

3 Figure 3a: Preoperative tooth 21 with a fractured root Figure 3b: Postoperative replacing tooth 21 with an implant involving soft tissue grafting. Treatment carried out by Dr Michael Zybutz 3a Who carries out the treatment? When examining the figures overleaf it is important to recognize whether the treatment was carried out by general dentists or by specialists. A survey carried out by the American Dental Association in 2002 showed that 90% of oral and maxillofacial surgeons and 70% of periodontists placed implants. Only 10% of prosthodontists and 8% of general dentists did the same. With the considerable marketing efforts of the implant industry, it is now not uncommon for general dental practitioners to place implants. It can be reasonably assumed that the reports of long-term success/survival rates would have been based on implants placed by those with post-graduate training in the handling of bone and soft tissues, and it is reasonable to speculate that the same level of success would not be duplicated in general practice (Listgarten, 1997). Similarly, many of the outcomes studies for endodontics would have been based on treatments performed outside of general dental practice. A review of 44,600 root treatments showed a survival of over 90% when two thirds of the treatments were carried in general practice (Lazarski et al, 2001). A comparison of five-year survival of endodontically treated teeth treated by specialists and general dentists showed a success rate of almost 90% for general dentists and 98% for specialists (Alley et al, 2004). Although it was a limited study involving only 350 teeth, the results are likely to be representative. What if treatment fails? As success cannot be guaranteed, a fall back position has to be considered in the event of failure. Implant failure is categorized as either early or late. Early failures (up to five months after placement) are those that have failed to integrate, and those that have been poorly positioned. They are usually due to poor treatment planning and/or poor surgical technique (Listgarten, 1997; Esposito et al, 1998). Late failures are usually due to peri-implantitis or occlusal overload (Cohn, 2005). An implant may be considered a failure in spite of successful osseointegration if an esthetic result has not been achieved. It has been well recognised that achieving an esthetic result with implants is significantly more challenging than with conventional restorations (Figures 3a and 3b). Failures at the front of the mouth are more commonly caused by poor esthetics than for mechanical reasons and when an implant fails the only course of action is its removal (Figures 4 and 5) (Goodacre et al, 2003). Endodontic failure is usually caused by the failure to remove microbes or failure to prevent their re-introduction (Sjogren et al, 1990; Ray and Trope, 1995). Very often an endodontic 3b failure can be re-treated by surgical or non-surgical means (Figures 6a and 6b) or a combination of the two. The best evidence for non-surgical re-treatment suggests a success rate similar to initial treatment where there is periradicular periodontitis, i.e % (Friedman, 2002; Ng et al, 2008a). Recent studies have suggested a similar success rate for surgical re-treatment. When microsurgical techniques have been used (operating microscope and ultrasonic tips for retrograde preparation), the success rates have been reported to be 95% (Kim et al, 2008). A recent presentation given by a member of one of the defense organizations has reported that currently the greatest number of settled claims (20%) were associated with failed endodontic treatment. Approximately one third of those were for incomplete obturation in the presence of residual infection/ pathology and another third for the presence of undisclosed fractured instruments. However, it was also reported that due to the time taken to settle claims, implants represented a significant growth area. Failed implants are likely to be associated with much higher costs than failed endodontic treatment. In Australia the incidence of malpractice claims is four times higher than for endodontics (DPL, 2001). The global value of the implant industry has been reported to be 2.2 billion US dollars per year (Eisner, 2006). The evidence of that is seen in the number of implant courses, articles and advertisements published in the dental press. With the pressure on GDPs to place implants, the growth in malpractice claims for implants can be anticipated. A comparison of endodontic and implant success A very small number of papers have started to appear in the literature making direct comparisons between implants and endodontically treated teeth. They show that there is very little difference in success rate, although implants do appear to require more maintenance (Doyle et al, 2006; Hannahan and Eleazer, 2008). The conclusions that can be drawn from this information are that there is no difference in survival outcome and, therefore, the clinical decisions have to be based on factors other than treatment outcome. These include: Degree of treatment complexity Restorability of the tooth Periodontal status Medical status Cost Skill of the practitioner 16 ENDODONTIC PRACTICE FEBRUARY 2010

4 Figure 4: Tooth 21 replaced with an implant Figure 5: Teeth 21 and 22 replaced with implants 4 5 Figure 6a: Tooth 26 inadequately root treated and showing periradicular radiolucencies Figure 6b: Tooth 26 re-root treated at eight month review 6a 6b Figure 8: An unfavourable crown root ratio makes extraction and an implant a more predictable option 7 Figure 7: Tooth 46 can be re-treated, although an implant may be a more predictable option 8 Patient s wishes (Iqbal and Kim, 2008). Degree of treatment complexity Both types of treatment can range between straightforward and very complex and careful diagnosis and case assessment is crucially important. With the availability of cone beam CT scanners, diagnosis and treatment planning for both treatment types can be far more accurate (Patel et al, 2009). Endodontic treatment can be complicated by the pulpal anatomy, previous treatment and challenging access. The availability of the operating microscope, nickel titanium rotary instrumentation, reliable apex locators and ultrasonic instruments have all contributed to improvements in the quality and predictability of endodontic treatment that can be provided. Implant treatment can be complicated by the anatomy of the site and the quantity and quality of the bone available. Where there is inadequate bone for implants the floor of the maxillary sinus can be lifted, the inferior dental canal can be repositioned and various bone enhancing techniques used. An esthetic evaluation also has to be carried out. Such factors as the smile line and biotype of the periodontium, in addition to the other factors mentioned, will have a bearing on the success of the implant. Restorability of the tooth The decision to either retain or remove an existing tooth will depend primarily on its restorability. This will be influenced by the amount of tooth remaining that has not been destroyed by the ravages of decay and previous dentistry. The ultimate strength and, therefore, long-term viability of the restored tooth will also be an important consideration (Figures 7 and 8). Complex stages of treatment, i.e. post removal, endodontic retreatment, placement of a new post and core, crown lengthening and a replacement crown, may achieve a technical success, but it places the tooth at risk of long-term failure (Bader, 2002). On the other hand, there is no justification for removing a tooth that, with careful endodontic treatment (or re-treatment) and restoration, can be made to be a healthy, functional and esthetic unit of the dentition. ENDODONTIC PRACTICE FEBRUARY

5 9a 9b 9c Figure 9a: Failing endodontic treatment, the tooth had been recommended for extraction and replacement with an implant Figure 10a: Preoperative perforation in the floor of the pulp chamber and a fractured instrument apically. The patient was advised to have an implant Figure 10b: A two-year review Figure 9b: Re-treatment of tooth in Figure 9a Figure 9c: Six month recall of tooth in Figure 9a 10a 10b Periodontal status Periodontal status is one of the most relevant clinical factors in the decision making process. The retention of a tooth with compromised attachment may mean that when the tooth is lost, there is inadequate bone for an implant. On the other hand, if the disease process can be brought under control, a tooth with a reduced bony support may be functional for many years (Nyman and Lindhe, 1979). Medical status There are no specific medical contra-indications to carrying out endodontic treatment, although there are conditions that can influence the course of the treatment and require modifications. Patients with a high susceptibility to caries, possibly related to drug induced dry mouth, may be better served with implants. Those with diabetes may be more prone to complications and delayed healing (Fuoad and Burleson, 2003). There are also few permanent contra-indications to implant placement, although there are factors that may influence the success. Smoking is considered to considerably reduce the success rate, although is not necessarily a contra-indication. Similarly, the immuno-suppressed patient may not be an ideal candidate for an implant. However, new research results are being published all the time and it is always worth checking the current advice. Patients on intravenous bisphosphonates should avoid dental extractions if possible due to osteonecrosis (Edwards at al, 2008) and, therefore, non-surgical endodontic treatment is the preferred option. In patients under the age of 25 every effort should be made to preserve the teeth due to continuing growth of the skull. Cost and time The cost of implants and time to complete treatment has always been considered to be higher than those for endodontic treatment, especially when sinus lift and bone augmentation procedures are added. However, when all the costs for restorative treatment are added up, there may be little difference. The costs of both alternatives and time frame should be evaluated and presented to the patient for consideration, along with all other relevant information. Skill of the practitioner and personal bias We have to recognize that we all have different experience, interests, skill levels and personal bias. The question what would you do if it was your tooth? is one often asked by the patient. If the practitioner feels that his or her level of skill is inadequate for the treatment that is in the best interest for the patient, then a referral to a colleague who has the experience, knowledge and equipment to determine the diagnosis and carry out treatment is appropriate. Failure to communicate options to the patient is indefensible. Increasing numbers of endodontic and implant specialists and those with further training should mean that referral becomes easier. Although each of us has his or her personal bias, this should not override objective factors (Figures 9a and 9b). A recent study showed that treatment options presented in a biased manner tend to be those chosen by the patient (Foster and Harrison, 2008). 18 ENDODONTIC PRACTICE FEBRUARY 2010

6 Patient s wishes Ultimately, when all the clinical and financial information has been given to the patient, he or she is in a position to make an informed choice. Not all decisions are logically based. The patient may decide that in spite of the advice given he or she would rather have the tooth extracted (possibly without having any replacement). Conversely, some people feel that the loss of a tooth is psychologically unacceptable and would rather try anything to save the tooth than lose it in spite of an uncertain prognosis. We can often be surprised by the survival of a tooth with a questionable prognosis. With the rate of development of dental implants, a question we might well ask is would you rather have an implant now or in 10 years time? Provided that the patient has been informed of the options, understands the level of risk and possible complications and is prepared to accept the consequences of potential failure, it may be acceptable to accede to the patient s wishes (Figures 10a and 10b). Conclusion In conclusion, the success rates of both implants and endodontic treatment is likely to be very similar when carried out by adequately trained and skilled practitioners and, therefore, other factors should have a more significant bearing on the decision. The complexity of treatment, restorability of the existing tooth and its periodontal status will be of greatest importance. The cost and patient s preference will also have some influence on the choice. The replacement of an existing tooth with an implant is often easier to accomplish than saving the tooth through endodontic treatment or re-treatment. It is vital that the skills in both fields continue to be developed and that there is close co-operation between the two specialties rather than competition. The expertise required to save teeth is an invaluable one and it is vital that it is not sacrificed at the alter of implants. EP References Alley BS, Kitchens GG, Eleazer PD (2004) Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology 98(1): American Dental Association Council on Scientific Affairs (2004) Dental endoseous implants: an update. Journal of the American Dental Association 135: Bader HI (2002) Treatment planning for implants versus root canal therapy: a contemporary dilemma. Implant Dentistry 11: Chen SC, Chueh LH, Hsaio CK, Tsia MY, Ho SC, Chiang CP (2007) An epidemiological study of tooth retention after nonsurgical endodontic treatment in a large population in Taiwan. 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