Resumen de A Randomized Double-Masked Clinical Trial Comparing Four Periodontitis Treatment Strategies: 5-Year Tooth Loss Results
Hans R. Preus, Per Gjermo, Vibeke Baelum
Background: Tooth loss is the ultimate negative consequence of periodontitis, and reports of the extent to which different treatment strategies may influence long-term tooth loss are hard to find. This study aims to test the hypothesis that there is no difference in 5-year clinical outcome of therapy in terms of tooth mortality between groups of patients treated with conventional scaling and root planing (SRP) over weeks or same-day full-mouth disinfection (FDIS), with or without adjunctive metronidazole (MET).
Methods: One hundred eighty-four patients with moderate-to-severe periodontitis were randomly allocated to one of four treatment groups: 1) FDIS+MET; 2) FDIS+placebo; 3) SRP+MET; and 4) SRP+placebo. Total 161 patients (88%) completed the 5-year follow-up examination, and data on number and timing of tooth extractions as well as pre-extraction diagnoses and reasons for extractions were analyzed.
Results: No differences were observed between groups with regard to number of, reasons for, or time of extractions in the four groups at baseline and 1, 3, and 5 years after treatment.
Conclusion: If extraction or retention of teeth is regarded as a measure of failure or success 5 years after completion of periodontal therapy, none of the four strategies produced an end result better than the other.
Tooth loss is the probable negative consequence of untreated periodontitis or failed or incorrect therapy.1 On the basis of the existing literature, it is difficult to assess the extent to which teeth are extracted as part of periodontal treatment planning (i.e., removal of “hopeless” teeth before treatment commencement) and to what extent periodontal treatment has been unable to ensure their preservation. Lindhe and Nyman2 reported extracting an average of 3.3 teeth/patient during the presurgical phase in a 5-year prospective intervention study among 75 patients, but these extractions consisted of teeth “which from endodontic and cariologic viewpoints could not be successfully treated, teeth with periodontal pockets extending down to the apex, and teeth which on prosthodontic indications should not be maintained.” Pihlstrom et al.3 reported on tooth loss during and up to 6.5 years after therapy among (initially) 17 patients, and found that 19 teeth were extracted. However, seven patients were lost to the study at different (and unknown) times after therapy, rendering the denominator for calculations of tooth loss rates somewhat uncertain. Even so, Pihlstrom et al.3 reported that eight teeth were extracted during therapy (≈8/17 = 0.5 tooth/patient) and of the remaining 11 teeth extracted, three were within the first year, two were extracted between 1 and 5 years, and the remaining four were extracted between 5 and 6.5 years. Carnevale et al.,4 in a retrospective study, found that an average of 1.9 teeth/patient were extracted during active periodontal treatment, whereas 16% of patients experienced average extractions of 1.3 teeth/patient during the supportive periodontal maintenance (PM) therapy phase, which had a mean duration of 7.8 years. To the best of the authors’ knowledge, tooth loss has not been studied as an outcome in randomized clinical trials (RCTs) of periodontal treatment. A systematic review of the effect of full-mouth treatment modalities for chronic periodontitis (CP), which stated tooth loss as the primary outcome, found no studies reporting results to this end,5 and a systematic review of clinical trials on effect of periodontitis therapies typically reported only on surrogate outcomes such as clinical attachment level (CAL) and probing depth (PD) changes.6 As pointed out by Hujoel,7 trials using true endpoints such as tooth loss are challenging, in part because tooth loss is a long-term outcome, whereas periodontal trials tend to be short-term, thereby rendering number of tooth loss events too small for statistical evaluation. Additional arguments against tooth loss as an outcome include claims regarding the subjective nature of decisions to extract teeth, as well as the argument that teeth may be extracted for reasons unrelated to periodontitis or PM. However, attempts to distinguish periodontal from non-periodontal tooth loss are fraught with problems, and it is unlikely that such distinctions can be made accurately. Hence, the answer to the question “periodontal or non-periodontal?” may well be “both.” This situation is well known in many other research areas (cancer screening results may differ profoundly), i.e., whether disease-specific or all-cause mortality endpoints are used to assess outcomes of screening programs.8 Because all-cause mortality, in contrast to disease-specific mortality, is known to be an unbiased outcome, it is generally preferred for evaluation of cancer screening programs. The same argument can be made for tooth loss, suggesting that all-cause tooth loss, rather than disease-specific tooth loss, should be used as the preferred tooth loss outcome in periodontal trials.
The present study is a 5-year RCT of four periodontal treatment modalities; 1-year results have previously been published.9,10 Although this trial was not planned with tooth loss as the primary endpoint, scarcity of such data makes it interesting to analyze and report tooth loss during the entire 5-year trial period with a view to assess whether long-term benefits of the four treatment modalities differ in terms of tooth retention.
