A perspective on clinical significance

Tooth survival and clinical outcomes up to 26 years after guided tissue regeneration therapy in deep intra-bony defects: Follow-up investigation of three randomized clinical trials

AIM

To investigate tooth survival and clinical long-term outcomes up to 26 years following guided tissue regeneration (GTR) therapy in deep intra-bony defects.

METHODS

Patients from three prospective clinical split-mouth studies, which investigated the outcomes of GTR therapy, were re-evaluated 21-26 years after surgery independent of the membrane type used, and tooth survival was assessed according to several site-specific and patient-related factors.

RESULTS

About 50 patients contributing 102 defects were available for this long-term follow-up. After up to 26 years (median 23.3 years), 52.9% of the teeth were still in situ. The median survival of the extracted teeth was 13.8 years. Patients with diabetes mellitus and/or smoking history lost significantly more teeth in the long term. Compared to the 1-year situation, there was no new median CAL loss after up to 26 years in the teeth which were still in situ.

CONCLUSIONS

Within the limitations of this study, our data show that more than 50% of the initially seriously diseased teeth were still in situ up to 26 years following GTR therapy despite an overall limited adherence to SPT. In the majority of these teeth, the CAL gain 1 year after GTR could be maintained over this long period.

Influence of autogenous platelet concentrate on combined GTR/graft therapy in intra-bony defects: A 13-year follow-up of a randomized controlled clinical split-mouth study

AIM

To investigate the clinical long-term outcomes 13 years following guided tissue regeneration (GTR) in deep intra-bony defects with and without additional application of autogenous platelet concentrate (APC).

METHODS

In 25 patients, two deep contra-lateral intra-bony defects were treated according to GTR using β-TCP and bio-resorbable membranes. In test defects, APC was applied additionally. After 13 years, clinical healing results were assessed and compared to results at baseline and after 1 year. Furthermore, a tooth survival analysis was carried out.

RESULTS

After 13 years, 22 patients were available for tooth survival analysis showing 81.8% of test and 86.4% of control teeth still in situ. Based on the 15 patients still available for split-mouth analysis, median CAL was 10.0 mm in test and 12.0 mm in control sites at baseline. After 1 year, both groups revealed significant CAL gains of 5.0 mm, followed by a new CAL loss of 1.0 mm in the following 12 years. There were no significant differences between test and control sites.

CONCLUSION

Within the limits of this study, the data show that most of the CAL gain following GTR can be maintained over 13 years. The additional use of APC had no positive influence on the long-term stability.

Acellular dermal matrix and subepithelial connective tissue grafts for root coverage: A systematic review

BACKGROUND

The aim of this systematic review was to evaluate whether patients with gingival recession would benefit from an acellular dermal matrix graft (ADMG) in ways that are comparable to the gold standard of the subepithelial connective tissue graft (SCTG).

MATERIALS AND METHODS

A systematic review and meta-analysis comparing ADMG to SCTG for the treatment of Miller Class I and II recession defects was conducted according to PRISMA guidelines. PubMed, Excerpta Medica Database, and Cochrane Central Register of Controlled Trials databases were searched up to March 2016 for controlled trials with minimum 6 months duration. The primary outcome was root coverage; secondary outcomes included attachment level change, keratinized tissue (KT) change, and patient-based outcomes. Both authors independently assessed the quality of each included trial and extracted the relevant data.

RESULTS

From 158 potential titles, 17 controlled trials were included in the meta-analysis. There were no differences between ADMG and SCTG for mean root coverage, percent root coverage, and clinical attachment level gain. ADMG was statistically better than SCTG for gain in width of KT (-0.43 mm; 95% confidence interval: -0.72, -0.15). Only one study compared patient-based outcomes.

CONCLUSION

This review found that an ADMG would be a suitable root coverage substitute for an SCTG when avoidance of the second surgical site is preferred.

Using prognostic factors from case series and cohort studies to identify individuals with poor long-term outcomes during periodontal maintenance

BACKGROUND

The accuracy of applying prognostic factors to individual patients is uncertain.

AIM/METHOD

The aim was to apply prognostic factors from several outcome studies (case series and cohort) to identify: (1) patients who lost a tooth/teeth during periodontal maintenance; (2) patients who were non-responding to treatment; (3) patients needing re-treatment during periodontal maintenance. In addition, tooth loss was related to initial prognosis and it was determined which of the prognostic factors were also risk factors. Chi squared analysis was carried out for the outcomes of patients with-, and without prognostic factors. Significance level was set at p ≤ 0.05. Sensitivity and specificity was calculated for patients with and without prognostic factors.

RESULTS

The prognostic factors only identified a small proportion of patients who lost teeth (34-38%). Combining the prognostic factors resulted in a lower accuracy. A higher proportion of patients with no prognostic factors lost teeth (53.8-96.2%). The chance of identifying a non-responding patient based on family history was 5.9%, for stress 32.4%, and for heavy smoking 8.7%. Significantly more patients (29/40 , χ² = 16.2 p < 0.05) with initial uncertain/poor prognosis and significantly fewer patients (11/40, χ² = 16.2, p < 0.05) with erratic/no compliance needing re-treatment were identified. 21 of 40 patients (52.5%) (p = 0.655) with family history needing retreatment were identified. Combining the prognostic factors identified 5-22% out of a total of 40% of patients needing re-treatment. six out of nine (67%) teeth with an initial hopeless prognosis were lost, 10/109 (9%) teeth with a poor prognosis were lost, 11/346 (3%) teeth with a moderate prognosis were lost and 9/1972 (0.46%) of teeth with a good prognosis were lost. None of the prognostic factors was found also to be a risk factor for developing periodontal diseases.

CONCLUSION

Applying prognostic factors to identify individual patients with poor long-term outcomes is associated with low accuracy.

Coffee consumption and periodontal disease in males

BACKGROUND

Coffee is a major dietary source of antioxidants as well as of other anti-inflammatory factors. Given the beneficial role of such factors in periodontal disease, whether coffee intake is associated with periodontal disease in adult males was explored.

METHODS

Existing data collected by a prospective, closed-panel cohort study of aging and oral health in adult males was used. Participants included the 1,152 dentate males in the Veterans Affairs (VA) Dental Longitudinal Study who presented for comprehensive medical and dental examinations from 1968 to 1998. Mean age at baseline was 48 years; males were followed for up to 30 years. Participants are not VA patients; rather, they receive their medical and dental care in the private sector. Periodontal status was assessed by probing depth (PD), bleeding on probing, and radiographic alveolar bone loss (ABL), measured on intraoral periapical radiographs with a modified Schei ruler method. Moderate-to-severe periodontal disease was defined as cumulative numbers of teeth exhibiting PD ≥4 mm or ABL ≥40%. Coffee intake was obtained from participant self-reports using the Cornell Medical Index and food frequency questionnaires. Multivariate repeated-measures generalized linear models estimated mean number of teeth with moderate-to-severe disease at each examination by coffee intake level.

RESULTS

It was found that higher coffee consumption was associated with a small but significant reduction in number of teeth with periodontal bone loss. No evidence was found that coffee consumption was harmful to periodontal health.

CONCLUSION

Coffee consumption may be protective against periodontal bone loss in adult males.

Using a Delphi Panel to Survey Criteria for Successful Periodontal Therapy in Posterior Teeth

BACKGROUND

Health care providers have focused on outcome measures to determine the success or failure of treatment. In periodontics, there is no consistent view regarding what outcome measure(s) is(are) important for successful treatment. This study used a Delphi surveying technique to determine which outcome measures were clinically relevant to an expert panel of periodontists.

METHODS

The Delphi surveyed 35 periodontists from the United States to determine the level of importance of attachment level, probing depth, furcation involvement, mobility, plaque, inflammation, esthetics, pain, and patient satisfaction following periodontal treatment of posterior teeth in a patient with severe chronic periodontitis. The Delphi panelists were questioned concerning the relative importance of each outcome measure, a minimally acceptable level considered necessary for success for each outcome measure, and the length of time required for these outcome measures to remain stable.

RESULTS

Following two rounds of Delphi surveys, the panelists considered the control of pain to be an "extremely important" outcome measure for successful periodontal treatment. Attachment levels, probing depths, plaque levels, degree of inflammation, function, furcation involvement, and patient satisfaction were considered to be "very important" outcomes for successful periodontal treatment. The minimally acceptable reduction in probing depths following 1 year of treatment was 2 mm; whereas up to 1 mm of attachment loss was considered acceptable. The panel found that Glickman grade 2 furcation involvement or Miller degree II mobility would be considered an acceptable outcome for clinical success. Finally, the panel agreed that the 1-year results of treatment should remain stable for a minimum of 5 years.

CONCLUSIONS

The Delphi surveying technique proved useful in developing a hierarchy for the relevance of periodontal outcome measures. Absence of pain was the only outcome measure considered to be "extremely important" for successful therapy. Although panelists considered attachment loss, furcation invasions, and mobility as "very important" outcomes, they were willing to accept loss of attachment of up to 1 mm, grade 2 furcation involvement, and degree II mobility following treatment as long as outcomes remained stable for 5 years. These data suggest that minimal standards for success of posterior teeth can be established among periodontal practitioners.

Long-term stability of periodontal conditions achieved following guided tissue regeneration with bioresorbable membranes: case series results after 6-7 years

OBJECTIVES

To evaluate the results of guided tissue regeneration (GTR) treatment of intrabony defects with bioresorbable membranes after 6-7 years, and to disclose factors that may influence the long-term outcome of the treatment.

METHODS

Twenty-five defects in 19 patients were treated by means of polylactic acid/citric acid ester copolymer bioresorbable membranes. At baseline and after 1 and 6-7 years, the following parameters were recorded: (1) probing pocket depth (PPD), (2) gingival recession (REC), (3) probing attachment level (PAL)=PPD+REC, (4) presence/absence of plaque (PI), (5) presence/absence of bleeding on probing (BOP). Smoking habits and frequency of dental-control visits were also recorded. Significance of differences between categorical variables was evaluated with McNemar's test, and between numerical variables with the t-test for paired observations. Generalized linear models were constructed to evaluate the influence of various factors on PAL gain and PPD changes from 1 to 6-7 years. Association of smoking, frequency of dental controls, oral hygiene, and BOP with sites losing > or =2 mm in PAL was evaluated with Fisher's exact test.

RESULTS

At baseline, a mean PPD of 8.7+/-1.1 mm and a mean PAL of 9.8+/-1.5 mm was recorded. Statistically significant clinical improvements were observed at 1 and 6-7 years after GTR treatment. An average residual PPD of 3.8+/-1.1 mm and a mean PAL gain of 3.8+/-1.4 mm were observed after 1 year. After 6-7 years the corresponding values were 4.7+/-1.3 and 3.6+/-1.4 mm, respectively. There were no statistically significant differences between the 1- and the 6-7-year values. At the 6-7-year control, only 16% of the sites had lost > or =2 mm (maximum 3 mm), of the PAL gain obtained 1 year after GTR treatment. None of the sites had lost all of the attachment gained 1 year after treatment. Smoking, frequency of dental controls, oral hygiene, and BOP did not seem to influence the change of PPD and PAL gain, or the stability of PAL gain (i.e. losing PAL or not) from 1 to 6-7 years from treatment.

CONCLUSION

Clinical improvements achieved by GTR treatment of intrabony defects by means of bioresorbable membranes can be maintained on a long-term basis.

A Method to Enhance Determining the Clinical Relevance of Periodontal Research Data: Number Needed to Treat (NNT)

It would be advantageous if clinical trials reported both statistical and clinically meaningful results. In this regard, determination of the number of sites that would need to be treated in a test group to provide a beneficial result or prevent an adverse event at one additional site beyond the control group would provide useful information. This editorial addresses the use of NNT (number needed to treat) calculations to enhance determining the clinical relevance of periodontal research findings. The application, requirements for use, benefits, and limitations of employing NNT calculations are discussed.

Clinical Relevance of Adjunctive Minocycline Microspheres in Patients With Chronic Periodontitis: Secondary Analysis of a Phase 3 Trial

BACKGROUND

A recent Phase 3 trial demonstrated that adjunctive treatment with minocycline microspheres resulted in significant reductions in patient mean probing depths as compared to scaling and root planing (SRP) alone. The objective of the present study was to evaluate clinical relevance of these changes within the trial using proposed site-based criteria.

METHODS

A total of 499 patients with moderate to advanced chronic periodontitis were enrolled in a multi-center trial and randomized to either: 1) SRP alone or 2) SRP plus minocycline microspheres. Subjects received complete probing examinations including the measurement of probing depths at baseline, and 1 and 3 months. Probing depth reductions were tabulated by treatment, examination time, and baseline depths, and inter-group differences were evaluated with logistic regression models for correlated data.

RESULTS

Significantly more sites treated with adjunctive minocycline microspheres exhibited probing depths < 5 mm at 1 (P = 0.0009) and 3 (P = 0.01) months as compared to sites treated with SRP alone, both in the overall population and in smokers. In addition, significantly more sites decreased by 1, 2, or 3 mm in the adjunctive minocycline group than in the SRP alone group at 1 and 3 months, both overall as well as in smokers (P < 0.05).

CONCLUSION

This secondary analysis indicates that treatment with SRP plus minocycline microspheres is consistently more effective than SRP alone in providing clinically relevant site-based responses in patients with chronic periodontitis.

Clinical versus statistical significance as they relate to the efficacy of periodontal therapy

BACKGROUND

The author discusses the shortcomings of using statistical significance testing as a method to infer that results of periodontal clinical trials are clinically meaningful. To compensate for these deficiencies, he also identifies criteria and periodontal parameters that can be used to reflect clinically significant outcomes.

TYPES OF STUDIES REVIEWED

The author searched the medical and dental literature to identify commentaries that addressed the problems associated with interpreting statistical significance testing, or hypothesis testing, and defining clinical significance.

RESULTS

The limitations of statistical significance testing related to identifying clinically significant changes include failure to indicate if the detected differences between variables in test and control groups are large or important. After reviewing various definitions of the term "clinical significance," the author reviews and proposes a comprehensive working definition of it. Regarding the efficacy of periodontal therapy, he delineates the advantages and limitations of specific criteria (such as absolute values, cut points) that can be used to define clinical significance.

CLINICAL IMPLICATIONS

The author suggests that clinically significant results should be defined before initiating a study and statistical significance testing should be used to validate that findings did not occur by chance. This would help place the importance of clinical data into perspective, and it would enhance clinicians' ability to select the most appropriate therapies for particular sites in periodontal patients.

Predictive value of morphologic parameters for successful correction of Class II Division 2 malocclusion

The aim of this study was to assess the predictive value of pretreatment cephalometric parameters and apical base size for successful correction of Angle Class II Division 2 malocclusion. Pretreatment lateral cephalograms and pretreatment and posttreatment study casts of 96 subjects with Class II Division 2 malocclusions were examined to obtain 23 cephalometric parameters and to measure the size of the apical bases. Success of occlusal correction was evaluated as the percentage of change of peer assessment rating scores during treatment; percentage of change was the dependent variable in multivariate statistical analyses used to test the predictive value of the assessed parameters. Cephalometric parameters of pretreatment craniofacial morphology were insignificant as predictors of successful orthodontic correction of the malocclusions. Maxillary apical base size was the strongest predictor of occlusal correction and might serve as a valuable diagnostic predictor of successful treatment outcome.

Shape and size of teeth of dogs and cats-relevance to studies of plaque and calculus accumulation

Crown width, height and buccal surface areas were measured on heads or skulls of four dogs and four cats, and were compared with similar measurements on models of human dentition. Buccal surface area variability was greater in dogs and cats than in humans, and teeth of cats were smaller. Horizontal (gingival and occlusal halves) and vertical (mesial, middle, and distal thirds) buccal surface area variability was also greater in canine and feline teeth compared with human teeth. This increased variability suggests the need for testing of reliability and repeatability of scoring when using plaque and calculus indices based on horizontal or vertical segmentation. Buccal surface area variability between teeth also prompts questioning the validity of equal weighting of smaller, irregularly-shaped teeth when calculating a mean mouth score. Whether equal or more reliable results would be obtained from scores of whole teeth in comparison with segmentation indices used currently has yet to be determined.