Surgical periodontal pocket elimination: still a justifiable objective?

The survival rate of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteroides forsythus following 4 randomized treatment modalities

The overall goal of this clinical study was to determine the short-term anti-infective effects of four randomized treatment modalities on Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Bacteroides forsythus (Bf) and determine the effects of bacterial survival on treatment outcomes in patients with adult periodontitis. Twelve adult patients requiring therapy for moderate periodontitis were selected for this study. All patients had at least one tooth in each quadrant that had an inflamed pocket of probing depth > or =5 mm with probing attachment loss that harbored at least one of the following three periodontal pathogens: Aa, Pg, or Bf. The number of target organisms per site was determined pre-operatively, at 1 week, and 1 month and 3 months postoperatively utilizing DNA probes. One quadrant in each patient was randomly assigned to each one of the following four treatment groups: 1) scaling and root planing (SRP group); 2) pocket reduction through osseous surgery and apically-positioned flap (OS group); 3) modified Widman flap (MWF group); and 4) modified Widman flap and topical application of saturated citric acid at pH 1 for 3 minutes (CA group). The 4 treatment modalities were performed in one appointment. No postoperative antibiotics were used. Patients were instructed to supplement their daily oral hygiene with chlorohexidine oral rinse during the study. The results of this investigation indicated that: 1) none of the treatment modalities was effective in eliminating the target species; 2) the incidence of infected sites for all groups was 100% preoperatively; 62.5%, 33.3%, and 31.3% at 1 week, and 1 and 3 months postoperatively, respectively; 3) these infected sites lost 1.1 +/- 0.4 mm of probing attachment compared to gain of 0.0 +/- 0.3 mm for uninfected sites; 4) the infected sites had higher plaque and bleeding on probing 0.9 +/- 0.3, 73 +/- 12%, respectively, compared to 0.3 +/- 0.1 and 30 +/- 8% for the uninfected sites; and 5) no statistically significant differences were detected among the infected sites in regard to gingival index (1.0 +/- 0.2 vs. 0.8 +/- 0.1) or probing depth (3.5 +/- 0.4 vs. 3.0 +/- 0.1 mm). These results indicate that bacterial survival negatively affects the short-term clinical outcomes of non-surgical and surgical periodontal therapy.

Evaluating the validity of probing attachment loss as a surrogate for tooth mortality in a clinical trial on the elderly

Most periodontal trials are based on the assumption that the superior treatment, as judged by short-term intangible changes in probing attachment levels (the surrogate), is also the treatment most likely to affect tooth mortality. This assumption is valid if: (1) the surrogate is informative about tooth mortality, and (2) the surrogate captures a substantial proportion of the treatment effect on tooth mortality (e.g., > 50% or 75%). The goal of this study was to evaluate whether both conditions were satisfied in a randomized controlled trial (RCT) of elders at high risk for dental diseases. The results suggested that the first condition for a valid surrogate was satisfied: Both one- and two-year changes in probing attachment level were informative about tooth mortality risk. A 1-mm loss measured over a one-year period was associated with a 56% increased tooth mortality risk (relative risk = 1.56; 95% confidence interval, 1.08 to 2.26; p = 0.017); a 1-mm loss measured over a two-year period was associated with a 102% increased risk for tooth mortality (relative risk = 2.02; 95% confidence interval, 1.26 to 3.25; p = 0.004). The second condition necessary for a valid surrogate could not be confirmed in the present trial. With 95% confidence, it was concluded that one-year changes in probing attachment level measurements did not capture a significant proportion of the treatment effect (point estimate, 6%; 95% confidence interval;-38% to 53%). No useful statements could be made regarding the proportion of treatment effect captured by two-year changes, due to the width of the confidence interval (point estimate, 18%; 95% confidence interval;-151% to 140%). It is concluded that (1) the evidence surrounding the one-year change in probing attachment level indicates that it can be ruled out as being anything more than a weak surrogate marker for tooth mortality, and (2) further research is required to study the validity of two-year change in probing attachment level as a surrogate marker. Due to characteristics of the population and the treatments investigated, the generalizability of these findings to other RCTs is questionable.

Long-term evaluation of periodontal therapy: I. Response to 4 therapeutic modalities

Eighty-two periodontal patients were treated in a split mouth design with coronal scaling (CS), root planing (RP), modified Widman surgery (MW), and flap with osseous resection surgery (FO) which were randomly assigned to various quadrants in the dentition. Therapy was performed in 3 phases: non-surgical, surgical, and supportive periodontal treatment (SPT) < or = 7 years. Clinical data consisted of probing depth (PD), clinical attachment level (CAL), gingival recession (REC), bleeding on probing (BOP), suppuration (SUP), and supragingival plaque (PL). Because of the necessity to exit many CS treated sites due to breakdown, data for CS were reported only up to 2 years. All therapies produced mean PD reduction with FO > MW > RP > CS following the surgical phase for all probing depth severities. By the end of year 2 there were no differences between the therapies in the 1 to 4 mm sites. There were no differences in PD reduction between MW and RP treated sites by the end of year 3 in the 5 to 6 mm sites and by the end of year 5 in the > or = 7 mm sites. FO produced greater PD reduction in > or = 5 mm sites through year 7 of SPT. Following the surgical phase, FO produced a mean CAL loss and CS and RP produced a slight gain in 1-4 mm sites. RP and MW produced a greater gain of CAL than CS and FO following the surgical phase in 5 to 6 mm sites, but the magnitude of difference decreased during SPT. Similar CAL gains were produced by RP, MW, and FO in sites > or = 7 mm. These gains were greater than that produced by CS and were sustained during SPT. Recession was produced with FO > MW > RP > CS. This relationship was maintained throughout SPT. The prevalences of BOP, SUP, and PL were greatly reduced throughout the study and were comparable between sites treated by RP, MW, and FO while the CS sites had more BOP and SUP.

Long-term evaluation of periodontal therapy: II. Incidence of sites breaking down

Eighty-two patients were treated in a split mouth design with coronal scaling (CS), root planing (RP), modified Widman surgery (MW), and flap with osseous surgery (FO) which were randomly assigned to the various quadrants in the dentition. Following phase I and phase II therapy, the patients received supportive periodontal treatment (SPT) at 3-month intervals for up to 7 years. Clinical attachment level (CAL) was determined initially, post-phase I, post-phase II and prior to each SPT appointment. If a site lost > or = 3 mm of CAL from its baseline, it was classified as a breakdown site. Baselines were the initial exam for sites treated by CS and 10 weeks post-phase II for sites treated by RP, MW, and FO. Data were grouped by probing depth (PD) severity at the initial exam and at post-phase II. The breakdown for CS sites was assessed separately from RP, MW, and FO sites because of different baselines and retreatment protocols. Sites treated by CS had a higher incidence of breakdown than the other therapies through year 1 of SPT. The breakdown incidences/year for RP and MW sites were similar and greater than for FO sites in 1 to 4 mm and 5 to 6 mm PD categories. Breakdown incidence of RP sites was greater than MW sites which was greater than FO sites initially > or = 7 mm. Differences in incidence of breakdown between therapies after recategorizing data by post-phase II PD were the same as above, except no difference was present between RP and MW sites > or = 7 mm. Breakdown incidences were greater in increasing PD severities regardless of when they were categorized. There was no further loss of CAL one year after retreatment in 88% of sites. Patients with higher breakdown incidences tended to be smokers at the initial exam.

Definitive vs. exploratory periodontal trials: a survey of published studies

Definitive and exploratory randomized controlled trials (RCTs) have different goals as well as different design and analysis characteristics. The goal of definitive studies is to provide unequivocal evidence of a treatment's tangible benefit to the patient; a pre-trial-specified hypothesis is tested by use of a pre-trial-specified method. The goal of exploratory studies is to elucidate biological treatment mechanisms, to identify promising treatments, and to generate hypotheses for definitive studies; multiple hypotheses are evaluated to extract as much information from the data as possible. The purposes of this study were: (1) to survey selected design and analysis characteristics of randomized controlled periodontal trials published between 1988 and 1992 (n = 86), and (2) to classify trials as exploratory or definitive studies. The peridontal RCTs surveyed were typical of exploratory studies whose primary goal was to elucidate biological treatment mechanisms. Trial reports indicated the testing of multiple hypotheses (> or = 6 hypothesis tests in 70 of the 86 trials) on a variety of biological markers (86 out of 86 trials). The sample size (< or = 30 subjects in 67 out of 86 trials), duration (< or = 6 months in 65 out of 86 trials), and design and analysis characteristics (e.g., an absence of masking in 57 out of 86 trials) were also typical of exploratory studies which strive to obtain quick answers (short duration) at a low cost (small sample size; accept bias for increased efficiency and a lower cost). No definitive trials were identified.(ABSTRACT TRUNCATED AT 250 WORDS)

A survey of endpoint characteristics in periodontal clinical trials published 1988-1992, and implications for future studies

Endpoints are conditions or events that are associated with individual study subjects and that are used to assess treatment efficacy. 2 types of endpoints can be distinguished: "true" endpoints (reflect unequivocal evidence of tangible benefit to the patient) and "surrogate" endpoints (usually a measure of disease process). The purpose of this study was to survey four aspects of endpoint usage in randomized controlled trials (RCT's) on the treatment of periodontitis: (1) the typical number of endpoints per RCT, (2) the proportion of RCTs using the same endpoint, (3) the proportion of RCTs using true endpoints, and (4) whether treatment choice influenced endpoint choice. 92 publications (1988-1992) reporting on 82 RCT's were identified. The typical number of endpoints per RCT was 6 (range: 1-28). The 3 most frequently used endpoints were mean probing depth (78% of the trials), mean probing attachment level (66%), and the plaque index (37%). In total, 153 distinct surrogate endpoints were defined. Most of these were used infrequently; over 80% of the 153 endpoints were used in fewer than 5 of the 82 trials. No trials used tooth loss as a true endpoint. In the design of an RCT, treatment choice influenced surrogate endpoint choice. Surrogate endpoints based on re-entry surgery were exclusively used for regenerative procedures and microbiological surrogate endpoints were mostly used for RCT's on anti-microbials. The conclusion is that the typical RCT used multiple surrogate endpoints, some of which were used infrequently by other trials. Such endpoint usage characteristics are suitable for exploratory RCTs (designed to identify active treatments or to elucidate treatment mechanisms). The question is raised as to whether periodontal research has reached the point of needing properly designed definitive studies, whose purpose it would be to provide unequivocal evidence of tangible benefits to the patient by the various treatments. If a need for definitive randomized controlled trials is perceived, then the use of (multiple) surrogate endpoints as primary outcomes should be questioned. Surrogate endpoint usage has led to both false positive and false negative conclusions in other chronic disease studies. Endpoint selection and validation in RCTs may be an important element in resolving controversies about periodontal treatments.

Dental bacterial plaques. Nature and role in periodontal disease

Antony van Leeuwenhoek first described oral bacteria. However, not until almost 200 years later was the famous Koch postulate introduced. Since then, research has extensively been performed regarding the development and microbiology of dental plaques. In spite of the complexity of the developing flora of supragingival plaque, culture studies have shown a remarkably orderly succession of organisms. Lately, the concept of microbial specificity in the etiology of periodontal diseases has been widely suggested, i.e., that different forms of periodontal disease are associated with qualitatively distinct dental plaques. Cross-sectional and longitudinal studies of the predominant cultivable microflora reveal that only a small number of the over 300 species found in human subgingival plaques are associated with periodontal disease. Among the commonly mentioned are: Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, Bacteroides intermedius, Capnocytophaga sp., Eikenella corrodens, Fusobacterium nucleatum, and Wolinella recta, as well as certain gram-positive bacteria such as Eubacterium species. Anti-infective therapy for many systemic infections equals the use of antimicrobial drugs. However, for localized infections like periodontal diseases, treatment may consist of a combination of mechanical wound debridement and the application of an antimicrobial agent. The general effectiveness of mechanical anti-infective therapy and successful oral hygiene in the management of periodontal disease is well established in the literature and has met the test of success in clinical practice for most cases of periodontitis in adults. The definition of periodontal pathogens as either opportunistic pathogens, or as exogenous pathogens carries with it significant implications.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term assessment of periodontal surgery versus curettage or scaling and root planing

The various treatments for periodontal disease must be assessed in light of the recently articulated goals of periodontal therapy to preserve teeth for a lifetime and to enhance esthetics and comfort as well as oral health. This article examines the long-term comparisons of periodontal surgery, curettage, and scaling and root planing in improving attachment levels instead of the more traditional pocket depth.

Is it time to reassess the public health implications of periodontal diseases? A review of current concepts

In 1981 the American Association of Public Health Dentists' Subcommittee on Preventive Periodontics called for a national initiative toward controlling periodontal disease, including the development of national policy statements from national dental organizations and the development of education programs for the public and the profession. Since the 1981 report, the findings of a diverse group of studies raises a variety of questions about the prevalence of periodontal diseases, the etiology and progression of the diseases, and the feasibility and practicality of controlling them. An examination of this new information leads to the conclusion that it is time to reassess the public health implications of periodontal diseases.