Prognostication in periodontics – science or art?

Patients expect dentists to be able to predict the course of a disease like periodontitis, to be able give them some idea of when they can expect to lose teeth and to advise them about the solutions that are available to manage that tooth loss. Indeed, the determination of prognosis carries much weight in the periodontal literature and has been described as ‘an integral part of periodontal practice’.¹ But how accurate is a clinician's determination of prognosis? Are there any systems that can be used to help determine periodontal prognosis more objectively? Is there a danger that, with the availability and increasing popularity of treatments like implants, that the temptation is to remove teeth sooner than is advisable? Are implants better than periodontally-involved teeth? These questions represent some difficult decisions and, maybe, ethical dilemmas that will be explored in this paper.

Periodontitis is a common condition affecting about half the adult population to some degree, with about 10% of the population suffering from a more severe form of the condition that threatens them with tooth loss over their lifetime.² Such patients may well require restorative treatment to manage their tooth loss but restorative solutions are at high risk of failure without full control of the underlying periodontal pathology (Figure 1). However, even this type of periodontitis can be successfully treated and maintained over patients' lifetimes with appropriate self-care, professional treatment and long-term supportive therapy (SPT). Periodontitis cannot be cured, but it can be controlled; maintenance of periodontal health and the prevention of disease recurrence over a lifetime is dependent on a high standard of self-care, involving both a high standard of biofilm control and patients making the right lifestyle choices (smoking, diet, weight, exercise and so on) that reduces their risk of disease. With these elements in place, all forms of periodontal therapy, both non-surgical and surgical management, can be effective. A 2005 systematic review³ showed that non-surgical therapy was more effective than surgical therapy in increasing attachment levels for initial pocket depths of up to 6 mm, but that surgical therapy may be more effective for pockets over this depth. However, the authors recognized that these findings were based on 12 month results and that longer term studies^{4, 5, 6} had shown that the long-term results of non-surgical therapy were equivalent to those of surgical procedures, even for deeper sites, with respect to maintenance of mean attachment levels and prevention of tooth loss. This was confirmed in a more recent systematic review⁷ comparing the long-term effects of four surgical therapies and one non-surgical therapy with follow-up periods of 2–13 years: it was found that most studies favoured non-surgical therapy in terms of attachment level gain, even for deeper initial pocket depths. Such treatment can control periodontal breakdown but it has long been recognized that improvements can only be maintained by ongoing self-care and regular professional SPT, with personal and professional biofilm control being the cornerstone of long-term stability. One study on 75 patients with severe periodontitis who were maintained for 14 years found very little recurrence of disease.⁸ Axelsson et al presented the results of a 30-year, prospective, controlled cohort study on tooth mortality, caries and periodontal disease progression; the patients who continued to the end of the study (375) were seen for SPT every 3–12 months (depending on individual needs) and tooth loss rates over the 30-year period were low (0.4–1.8), with many of the losses being due to reasons other than periodontitis.⁹ The evidence therefore indicates that periodontal treatment with proper SPT can maintain periodontal health in the majority over the long term, but it is also recognized that a small proportion of patients will, unpredictably, experience disease recurrence. This is when clinicians start ‘prognosticating’ – trying to predict what will happen to severely periodontally-affected teeth.