Measures of treatment efficacy

The effect of adjunctive subantimicrobial dose doxycycline therapy on GCF EMMPRIN levels in chronic periodontitis

BACKGROUND

The aim of the present randomized, double-masked, placebo-controlled, parallel-arm study was to examine the effectiveness of a 3-month regimen of subantimicrobial dose doxycycline (SDD) in combination with scaling and root planing compared to scaling and root planing alone on levels of gingival crevicular fluid (GCF) extracellular matrix metalloproteinase inducer (EMMPRIN) in patients with chronic periodontitis.

METHODS

GCF samples were collected, and clinical parameters, including probing depth (PD), clinical attachment level, gingival index (GI), and plaque index, were recorded. Thirty chronic periodontitis subjects were randomized to receive SDD or placebo. The SDD group received SDD (20 mg, twice a day) for 3 months plus scaling and root planing, whereas the placebo group took placebo capsules twice a day for 3 months and received scaling and root planing. The subjects were reevaluated at 3 and 6 months. At each visit, all clinical parameters were measured and GCF was sampled. GCF EMMPRIN levels were determined by Western immunoblotting assay. Intragroup comparisons were tested by the Friedman test followed by the Wilcoxon signed-rank test to analyze the significance of changes over time. The Mann-Whitney test was used to determine differences between the SDD and placebo groups.

RESULTS

Significant improvements were observed in all clinical parameters in the SDD group over the 6-month study period (P <0.025). The SDD group showed a significantly greater reduction in mean PD scores at 6 months and in mean GI scores at 3 and 6 months than the placebo group (P <0.05). From baseline to 6 months, the GCF EMMPRIN levels were reduced significantly in the SDD group (P <0.025). The GCF EMMPRIN level in the SDD group was significantly lower than that of the placebo group at 3 and 6 months (P <0.05).

CONCLUSIONS

SDD therapy in combination with scaling and root planing reduced GCF EMMPRIN levels and improved clinical periodontal parameters in subjects with chronic periodontitis. The ability of SDD to downregulate, in vivo, the GCF levels of EMMPRIN, a unique upregulator of matrix metalloproteinase expression, is one of its beneficial host-modulatory properties. These results expand the usefulness of SDD therapy as an adjunct to scaling and root planing in the long-term management of periodontal disease.

Subantimicrobial dose doxycycline effects on alveolar bone loss in post-menopausal women

AIM

Determine the efficacy of 2-year continuous subantimicrobial dose doxycycline (SDD; 20 mg bid) on alveolar bone in post-menopausal osteopenic, oestrogen-deficient women undergoing periodontal maintenance in a 2-year double-blind, placebo-controlled, randomized clinical trial.

MATERIAL AND METHODS

One-hundred and twenty-eight subjects randomized to SDD or placebo (n=64 each). Posterior vertical bite wings taken at baseline, 1 and 2 years for alveolar bone density (ABD), using radiographic absorptiometry (RA) and computer-assisted densitometric image analysis (CADIA), and alveolar bone height (ABH). Statistical analyses utilized generalized estimating equations; primary analyses were intent to treat (ITT). Results are presented as SDD versus placebo.

RESULTS

Under ITT, there was no statistically significant effect of SDD on ABD loss (RA: p=0.8; CADIA: p=0.2) or ABH loss (p=0.2). Most sites (81-95%) were inactive. For subgroup analyses, mean CADIA was higher with SDD for non-smokers (p=0.05) and baseline probing depths > or =5 mm (p=0.003). SDD was associated with 29% lower odds of more progressive ABH loss in women >5 years post-menopausal (p=0.05) and 36% lower among protocol-adherent subjects (p=0.03).

CONCLUSIONS

In post-menopausal osteopenic women with periodontitis, SDD did not differ overall from placebo. Based on exploratory subgroup analyses, additional research is needed to determine the usefulness of SDD in non-smokers, subjects >5 years post-menopausal and in deeper pockets. Protocol registered at (ClinicalTrials.gov). Identifier: NCT00066027.

Effect of subantimicrobial dose doxycycline as an effective adjunct to scaling and root planing

BACKGROUND

This study evaluated the efficacy and safety of a subantimicrobial dose of doxycycline (SDD) in conjunction with scaling and root planing (SRP).

METHODS

The study was a 9-month, double masked, randomized, placebo-controlled, parallel-group trial. A total of 41 patients with moderate chronic periodontitis who received SRP were randomly allocated to receive either a doxycycline hyclate or a placebo 2 weeks after SRP. Clinical attachment level (CAL), the probing depth (PD), gingival crevicular fluid (GCF) levels, and matrix metalloproteinase (MMP)-8 and -13 levels were measured throughout the study. The effect of SDD in conjunction with SRP on the dynamics of the periodontal microflora was also assessed using dark-field microscopic and culture analysis. Information on adverse events was collected throughout the study.

RESULTS

During the treatment period, per-patient reductions in PD and CAL were demonstrated for both treatment groups, with a significantly greater reduction for the SDD group. The mean value of per-patient change in the GCF was much greater for the SDD group. Microbial analysis showed there were a general tendency for cocci, non-motile rods, and aerobes to increase with increasing treatment duration and a general decreasing tendency for spirochetes, motile rods, and anaerobes and black pigmented bacteria in both treatment groups, but no significant difference between the groups. The MMP-8 and -13 levels of the SDD group gradually reduced with time, and the mean perpatient average was significantly higher than in the placebo group. The adverse events in the SDD group were similar to those in the placebo group.

CONCLUSION

This study suggests that a submicrobial dose of doxycycline as an adjunct therapy with SRP might be safe and effective in the long-term management of chronic periodontitis.

Subantimicrobial dose doxycycline as adjunctive treatment for periodontitis. A review

BACKGROUND

Subantimicrobial dose doxycycline (SDD--20 mg doxycycline twice daily) is indicated as an adjunctive treatment for periodontitis. Doxycycline downregulates the activity of matrix metalloproteinases (MMPs), key destructive enzymes in periodontal disease. Current understanding of periodontal pathogenesis suggests that MMPs play a major role in the destruction of periodontal tissues, leading to the clinical signs of periodontitis. Research supports that downregulation of MMPs by SDD confers benefit to patients with periodontitis.

METHOD

We review the clinical, microbiological and safety data relating to the use of SDD in patients with periodontitis, and consider the historical events that led to the development of adjunctive SDD as a treatment for periodontitis.

RESULTS

Studies have shown that SDD, when prescribed as an adjunct to scaling and root planing (SRP), results in statistically and clinically significant gains in clinical attachment levels and reductions in probing depths over and above those that are achieved by SRP alone. SRP must be thorough and performed to the highest standard to maximise the benefits of adjunctive SDD. SDD does not result in antibacterial effects, or lead to the development of resistant strains or the acquisition of multiantibiotic resistance. The frequency of adverse events is low, and does not differ significantly from placebo.

CONCLUSIONS

Adjunctive SDD confers clinical benefit to patients with periodontitis. A comprehensive treatment strategy is suggested, involving patient education and motivation, reduction of the bacterial burden by SRP, host response modulation with SDD, and periodontal risk factor modification.

Subantimicrobial Dose Doxycycline Enhances the Efficacy of Scaling and Root Planing in Chronic Periodontitis: A Multicenter Trial

BACKGROUND

Previous studies have shown that subantimicrobial dose doxycycline (SDD) is of clinical benefit in the treatment of chronic periodontitis (CP). The aim of this study was to further assess the role of SDD as an adjunct to scaling and root planing (SRP) in the treatment of CP.

METHODS

A double-blind, randomized, placebo-controlled, multicenter clinical study was conducted to test the efficacy of SDD (20 mg doxycycline B.I.D.) in combination with SRP in subjects with moderate to severe CP. Two-hundred ten subjects were treated with a standardized episode of SRP and randomized to receive either adjunctive SDD or placebo for 9 months. Efficacy parameters included per-subject mean changes in clinical attachment level (CAL) and probing depth (PD) from baseline, and the total number of sites with attachment gains and probing depth reductions > or = 2 mm and > or = 3 mm from baseline.

RESULTS

In periodontal sites with PD 4 to 6 mm and > or = 7 mm (N = 209, intent-to-treat population), mean improvements in CAL and PD were greater following SRP with adjunctive SDD than SRP with placebo, achieving statistical significance in all baseline disease categories at month 9 (P < 0.05). At month 9, 42.3% of sites in the SDD group demonstrated CAL gain > or = 2 mm compared to 32.0% of sites in the placebo group (P < 0.01). CAL gain > or = 3 mm was seen in 15.4% of sites in the SDD group compared to 10.6% of sites in the placebo group (P < 0.05). When considering the same thresholds of change in PD, 42.9% of sites in the SDD group compared to 31.1% of sites in the placebo group demonstrated PD reduction > or = 2 mm (P < 0.01), and 15.4% of sites in the SDD group compared to 9.1% of sites in the placebo group demonstrated PD reduction > or = 3 mm (P < 0.01).

CONCLUSION

Adjunctive subantimicrobial dose doxycycline enhances scaling and root planing. It results in statistically significant attachment gains and probing depth reductions over and above those achieved by scaling and root planing with placebo.

Treatment with subantimicrobial dose doxycycline improves the efficacy of scaling and root planing in patients with adult periodontitis

BACKGROUND

In a previous study, subantimicrobial dose doxycycline (SDD) significantly improved clinical parameters associated with periodontal health in patients with adult periodontitis (AP) when used as an adjunct to a maintenance schedule of supragingival scaling and dental prophylaxis. In this double-blind, placebo-controlled, parallel-group, multicenter study, the efficacy and safety of SDD were evaluated in conjunction with scaling and root planing (SRP) in patients with AP.

METHODS

Patients (n = 190) received SRP at the baseline visit and were randomized to receive either SDD 20 mg bid or placebo bid for 9 months. Efficacy parameters included the per-patient mean changes in clinical attachment level (CAL) and probing depth (PD) from baseline, the per-patient percentages of tooth sites with attachment loss (AL) > or = 2 mm and > or = 3 mm from baseline, and the per-patient percentage of tooth sites with bleeding on probing. Prior to analysis, tooth sites were stratified by the degree of disease severity evident at baseline

RESULTS

In tooth sites with mild to moderate disease and severe disease (n = 183, intent-to-treat population), improvements in CAL and PD were significantly greater with adjunctive SDD than with adjunctive placebo at 3, 6, and 9 months (all P <0.05). In tooth sites with severe disease, the per-patient percentage of sites with AL > or = 2 mm from baseline to month 9 was significantly lower with adjunctive SDD than with adjunctive placebo (P<0.05). Improvements in clinical outcomes occurred without detrimental shifts in the normal periodontal flora or the acquisition of doxycycline resistance or multiantibiotic resistance. SDD was well tolerated, with a low incidence of discontinuations due to adverse events.

CONCLUSIONS

The adjunctive use of SDD with SRP is more effective than SRP alone and may represent a new approach in the long-term management of AP.

Overview of periodontal clinical trials utilizing anti-infective or host modulating agents

Issues in periodontal trials designed to evaluate anti-infective or host modulating agents for the prevention and treatment of periodontal diseases are reviewed in this paper. Clinical trial designs, prevention versus treatment, disease activity, utility of new measurement technologies, ethical and safety issues, selection of outcome variables, and clinical significance are discussed. In general, randomized parallel arm, double-blinded, controlled clinical trials are most appropriate for testing anti-infective and host modulating agents. New measurement technologies may offer increased measurement resolution and automated data capture; but, depending on their specific application and level of examiner reproducibility, these technologies may or may not result in lowered thresholds for declaring change. Mechanical therapy for common plaque-associated gingivitis and adult periodontitis is effective, has low risk, and is widely accepted as a minimum standard of care. New agents for treatment of these diseases must carry minimal risk and have equal or greater effectiveness than this standard of care. Outcome variables for gingivitis trials should include a visual index of gingival inflammation and a separate or component index of gingival bleeding. Prevention studies of periodontitis require a longer duration than treatment studies. Maintenance of mean clinical attachment level should be a primary outcome measure for all prevention studies of adult periodontitis. Maintenance of alveolar bone support is an essential additional outcome for agents specifically acting on bone. The design and conduct of clinical trials for anti-infective and host modulating agents depend on the specific hypothesis to be tested and the ethical demands of providing safe and effective care for all study volunteers.

A study of the reliability of a no disease progression conclusion

Concluding that the clinical attachment level at a periodontal site is stable, while in reality it is progressing at a clinically relevant rate, is an example of a false-negative conclusion. No guidelines are currently available to evaluate the likelihood for false-negative conclusions in periodontal clinical trials that monitor disease progression by means of clinical attachment levels. The goal of this study was to estimate the amount of linear disease progression in clinical attachment levels that cannot reliably be detected, when it is truly present. This rate is called the critical linear rate; rates equal to or below this critical linear rate cannot reliably be detected. An equation for determining the critical linear rates for various clinical situations is presented and may provide a rule-of-thumb guideline for the interpretation of negative conclusions. If the critical linear rate for a study is larger than what is considered a clinically relevant disease progression rate, negative conclusions should be interpreted with caution; clinically relevant disease progression might be present, but the diagnostic tools used were too insensitive to detect it. False-negative conclusions may be important in diagnostic trials where low sensitivity can translate into lack of clinical utility.

Evaluation of periodontal treatments using controlled-release tetracycline fibers: maintenance response

The purpose of this investigation was to examine periodontal disease recurrence from 3 to 12 months following various treatments with scaling and root planing and controlled-release tetracycline fibers. One-hundred-twenty-two (122) adult volunteers with at least one bleeding pocket > or = 5 mm in each of four quadrants were enrolled in this study. One or two such sites in each quadrant were selected as test sites. Quadrants were randomly assigned to receive one of four treatments: scaling and root planing (S); scaling and root planing plus tetracycline fiber for 10 days (SF); fiber therapy alone for 10 days (F); or fiber therapy alone for 20 days (FF). After treatment, no supportive care was provided during the 12-month study period. Probing depth (PD), attachment loss (AL), plaque, and bleeding on probing were measured at baseline, and at 1, 3, 6, 9, and 12 months after treatment. PD and AL measures were taken at three locations within each site and averaged for each site. Disease recurrence was defined as > or = 1 mm mean attachment loss at a site during the 3- to 12-month period. One-hundred-sixteen (116) subjects completed the study. Sites treated with SF experienced significantly (P < 0.05) less disease recurrence (4%) than S, F, or FF (9%, 10%, and 12%, respectively). Results of this study suggest that, compared to S, F, or FF, scaling and root planing in conjunction with tetracycline fiber therapy for 10 days can significantly reduce disease recurrence 3 to 12 months following treatment in the absence of supportive care.