Logical and analytic issues in dental/oral product comparison research

Powered versus manual toothbrushing for oral health

BACKGROUND

Removing dental plaque may play a key role maintaining oral health. There is conflicting evidence for the relative merits of manual and powered toothbrushing in achieving this. This is an update of a Cochrane review first published in 2003, and previously updated in 2005.

OBJECTIVES

To compare manual and powered toothbrushes in everyday use, by people of any age, in relation to the removal of plaque, the health of the gingivae, staining and calculus, dependability, adverse effects and cost.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (to 23 January 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 1), MEDLINE via OVID (1946 to 23 January 2014), EMBASE via OVID (1980 to 23 January 2014) and CINAHL via EBSCO (1980 to 23 January 2014). We searched the US National Institutes of Health Trials Register and the WHO Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Randomised controlled trials of at least four weeks of unsupervised powered toothbrushing versus manual toothbrushing for oral health in children and adults.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration. Random-effects models were used provided there were four or more studies included in the meta-analysis, otherwise fixed-effect models were used. Data were classed as short term (one to three months) and long term (greater than three months).

MAIN RESULTS

Fifty-six trials met the inclusion criteria; 51 trials involving 4624 participants provided data for meta-analysis. Five trials were at low risk of bias, five at high and 46 at unclear risk of bias.There is moderate quality evidence that powered toothbrushes provide a statistically significant benefit compared with manual toothbrushes with regard to the reduction of plaque in both the short term (standardised mean difference (SMD) -0.50 (95% confidence interval (CI) -0.70 to -0.31); 40 trials, n = 2871) and long term (SMD -0.47 (95% CI -0.82 to -0.11; 14 trials, n = 978). These results correspond to an 11% reduction in plaque for the Quigley Hein index (Turesky) in the short term and 21% reduction long term. Both meta-analyses showed high levels of heterogeneity (I(2) = 83% and 86% respectively) that was not explained by the different powered toothbrush type subgroups.With regard to gingivitis, there is moderate quality evidence that powered toothbrushes again provide a statistically significant benefit when compared with manual toothbrushes both in the short term (SMD -0.43 (95% CI -0.60 to -0.25); 44 trials, n = 3345) and long term (SMD -0.21 (95% CI -0.31 to -0.12); 16 trials, n = 1645). This corresponds to a 6% and 11% reduction in gingivitis for the Löe and Silness index respectively. Both meta-analyses showed high levels of heterogeneity (I(2) = 82% and 51% respectively) that was not explained by the different powered toothbrush type subgroups.The number of trials for each type of powered toothbrush varied: side to side (10 trials), counter oscillation (five trials), rotation oscillation (27 trials), circular (two trials), ultrasonic (seven trials), ionic (four trials) and unknown (five trials). The greatest body of evidence was for rotation oscillation brushes which demonstrated a statistically significant reduction in plaque and gingivitis at both time points.

AUTHORS' CONCLUSIONS

Powered toothbrushes reduce plaque and gingivitis more than manual toothbrushing in the short and long term. The clinical importance of these findings remains unclear. Observation of methodological guidelines and greater standardisation of design would benefit both future trials and meta-analyses.Cost, reliability and side effects were inconsistently reported. Any reported side effects were localised and only temporary.

The effectiveness of manual versus powered toothbrushes for plaque removal and gingival health: A meta-analysis

BACKGROUND

The aim of this systematic review and associated meta-analysis was to compare manual and powered brushes in relation to the removal of plaque and gingival health. Stain removal, adverse effects and microbiological evaluation cost were also considered.

MATERIALS AND METHODS

To be included in the review, a trial had to be a randomized-controlled trial (RCT) comparing manual and powered brushes. Trials confined to comparing different types of powered or different types of manual brushes were excluded. Split mouth designs were eligible. Trials with subjects of specific age group (18-25 years) were included. The primary outcomes were plaque and gingival health with data defined as short-term (0-28 days) duration were analyzed. Powered brushes were categorized into three groups depending on mode of action. Numerical data extracted were checked by a fourth reviewer for accuracy.

RESULTS

Three trials with full articles were identified. These include trials published between 2002 and 2005. The trials involved 56 subjects at baseline, without loss of subject for follow up. Powered brushes reduced plaque and gingivitis at least as effectively as manual brushing. Ionic brushes statistically significantly reduced plaque and gingivitis.

CONCLUSION

In general there was no evidence of a statistically significant difference between powered and manual brushes. However, ionic brushes significantly reduce plaque and gingivitis in both the short-term evaluations. The clinical significance of this reduction is not known. Observation of methodological guidelines and greater standardization of design would benefit both future trials and meta-analyses.

Quality of trials in a systematic review of powered toothbrushes: suggestions for future clinical trials

BACKGROUND

This study aimed to assess the quality of reports of randomized controlled trials (RCTs) comparing manual and powered toothbrushes and provide advice on how future trials might be improved.

METHODS

Studies were identified in the Cochrane systematic review of RCTs comparing powered versus manual toothbrushes. Reports were assessed against predefined criteria on the design of the studies to determine the effectiveness of the brushes in everyday home use and on their methodological quality.

RESULTS

Only 42 of 297 identified studies satisfied the inclusion criteria and were eligible for inclusion in the review. Many studies were excluded for more than one reason. Fifteen studies employed split-mouth designs that may have changed toothbrushing behavior. Of 42 included RCTs, the generation of randomization sequence was adequate in 15 trials and concealment of allocation was adequate in 16 trials. Intention-to-treat analysis was reported in only five studies. Plaque data were reported using 10 different indices and gingivitis with nine indices. Only 12 trials lasted 3 months or longer, and there were no data on the benefits of powered toothbrushes for periodontal attachment.

CONCLUSIONS

Some designs created an artificial research environment that may have undermined the findings. Authors of toothbrush trials should consider the Consolidated Standards of Reporting Trials statement. Greater standardization of the indices used is required. Trials of longer duration would enhance the evaluation of powered toothbrushes. Data on thresholds for clinically significant differences in plaque and gingivitis levels would help to determine whether oral hygiene aids provide important health benefits.

Manual versus powered toothbrushing for oral health

BACKGROUND

Removing dental plaque may play a key role maintaining oral health. There is conflicting evidence for the relative merits of manual and powered toothbrushing in achieving this.

OBJECTIVES

To compare manual and powered toothbrushes in relation to the removal of plaque, the health of the gingivae, staining and calculus, dependability, adverse effects and cost.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group Trials Register (to 17/06/2004) and Central Register of Controlled Trials (The Cochrane Library Issue 2, 2004); MEDLINE (January 1966 to week 2 June 2004); EMBASE (January 1980 to week 2 2004) and CINAHL (January 1982 to week 2 June 2004). Manufacturers were contacted for additional data.

SELECTION CRITERIA

Trials were selected for the following criteria: design-random allocation of participants; participants - general public with uncompromised manual dexterity; intervention - unsupervised manual and powered toothbrushing for at least 4 weeks. Primary outcomes were the change in plaque and gingivitis over that period.

DATA COLLECTION AND ANALYSIS

Six authors independently extracted information. The effect measure for each meta-analysis was the standardised mean difference (SMD) with 95% confidence intervals (CI) using random-effects models. Potential sources of heterogeneity were examined, along with sensitivity analyses for quality and publication bias. For discussion purposes SMD was translated into percentage change.

MAIN RESULTS

Forty-two trials, involving 3855 participants, provided data. Brushes with a rotation oscillation action removed plaque and reduced gingivitis more effectively than manual brushes in the short term and reduced gingivitis scores in studies over 3 months. For plaque at 1 to 3 months the SMD was -0.43 (95% CI: -0.72 to -0.14), for gingivitis SMD -0.62 (95% CI: -0.90 to -0.34) representing an 11% difference on the Quigley Hein plaque index and a 6% reduction on the Loe and Silness gingival index. At over 3 months the SMD for plaque was -1.29 (95% CI: -2.67 to 0.08) and for gingivitis was -0.51 (-0.76 to -0.25) representing a 17% reduction on the Ainamo Bay bleeding on probing index. There was heterogeneity between the trials for the short-term follow up. Sensitivity analyses revealed the results to be robust when selecting trials of high quality. There was no evidence of any publication bias. No other powered designs were as consistently superior to manual toothbrushes.Cost, reliability and side effects were inconsistently reported. Any reported side effects were localised and temporary.

AUTHORS' CONCLUSIONS

Powered toothbrushes with a rotation oscillation action reduce plaque and gingivitis more than manual toothbrushing. Observation of methodological guidelines and greater standardisation of design would benefit both future trials and meta-analyses.

The effectiveness of manual versus powered toothbrushes for dental health: a systematic review

OBJECTIVES

To compare manual and powered toothbrushes in everyday use, principally in relation to plaque removal and gingival health. Stain, calculus removal, dependability, adverse effects and cost were also considered.

METHOD

A systematic review was undertaken in collaboration with the Cochrane Oral Health Group. Five electronic databases were searched to identify randomised controlled trials comparing powered and manual toothbrushes. Trials of less than 28 days duration, or where toothbrushing was supervised, were excluded. Assessment of relevance, data extraction and validity assessment were all undertaken independently and in duplicate by two reviewers. Included studies were grouped according to the mode of action of the powered toothbrush. The primary outcomes were plaque and gingival health with data defined as either short-term (1-3 months) or long-term (greater than 3 months) duration were analysed. Powered brushes were categorised into six groups depending on mode of action. Numerical data extracted were checked by a third reviewer for accuracy and entered into RevMan (version 4.1).

RESULTS

The initial search identified 354 studies. Two hundred and fifteen full articles were obtained of which 29 trials fulfilled the inclusion criteria with results, which could be entered in the meta-analysis. Twenty-six trials (1786 participants) reported short-term and 10 trials (798 participants) long-term plaque scores. Twenty-nine trials (2236 participants) reported short-term and 10 trials (798 participants) long-term gingivitis scores. Powered brushes reduced plaque and gingivitis at least as effectively as manual brushing. Rotation oscillation powered brushes statistically significantly reduced plaque and gingivitis in both the short and long-term. For plaque at one to 3 months the standardised mean difference was -0.44 (95% CI: -0.66 to -0.21), for gingivitis SMD -0.45 (95% CI: -0.76, -0.15). These represented an 11% reduction on the Quigley Hein Plaque index and a 6% reduction on the Löe and Silness gingival index. At over 3 months the effects were SMD for plaque -1.15 (95% CI: -2.02, -0.29) and SMD for gingivitis -0.51 (95% CI: -0.76, -0.25). These represented a 7% reduction on the Quigley Hein Plaque Index and a 17% reduction on the Ainamo Bay Bleeding on Probing Gingival Index. Sensitivity analyses revealed the results to be robust when selecting trials of high quality. There was no evidence of any publication bias. No other powered brush designs were consistently superior to manual toothbrushes. In these trials, data on cost, reliability and side effects were inconsistently reported.

CONCLUSION

In general there was no evidence of a statistically significant difference between powered and manual brushes. However, rotation oscillation powered brushes significantly reduce plaque and gingivitis in both the short and long-term. The clinical significance of this reduction is not known. Observation of methodological guidelines and greater standardisation of design would benefit both future trials and meta-analyses.

Manual versus powered toothbrushing for oral health

BACKGROUND

Specific oral bacteria, generically known as "dental plaque" are the primary cause of gingivitis (gum disease) and caries. The removal of dental plaque is thought to play a key role in the maintenance of oral health. There is conflicting evidence for the relative merits of manual and powered toothbrushing in achieving this.

OBJECTIVES

To compare manual and powered toothbrushes in relation to the removal of plaque, the health of the gingivae, staining and calculus, dependability, adverse effects and cost.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group's Trials Register (to 22/8/02); Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2002); MEDLINE (January 1966 to week 5 2002); EMBASE (January 1980 to week 3 July 2002) and CINAHL (January 1982 to June 2002). Manufacturers of powered toothbrushes were contacted for additional published and unpublished trials.

SELECTION CRITERIA

Trials were selected if they met the following criteria: design-random allocation of participants; participants-general public with uncompromised manual dexterity; intervention- supervised manual and powered toothbrushing for at least four weeks; primary outcomes-the change in plaque and gingivitis over that period.

DATA COLLECTION AND ANALYSIS

Six reviewers independently extracted information in duplicate. Indices for plaque and gingivitis were expressed as standardised values for each study. The effect measure for each meta-analysis was the standardised mean difference (SMD) with the appropriate 95% confidence intervals (CI) using random effect models. Potential sources of heterogeneity were examined, along with sensitivity analyses for the items assessed for quality and publication bias.

MAIN RESULTS

Twenty-nine trials, involving 2,547 participants, provided data for the meta-analysis. Brushes that worked with a rotation oscillation action removed more plaque and reduced gingivitis more effectively than manual brushes in the short and long term. For plaque at one to three months the SMD was -0.44 (95% CI: -0.66 to -0.21), for gingivitis SMD -0.44 (95% CI: -0.72, -0.15). These represented an 11% reduction on the Quigley Hein plaque index and a 6% reduction on the Löe and Silness gingival index. At over three months the effects were SMD for plaque -1.15 (95% CI: -2.02,-0.29) and SMD for gingivitis -0.51 (95% CI: -0.76, -0.25). These represented a 7% reduction on the Quigley Hein Plaque Index and a 17% reduction on the Ainamo Bay Bleeding on Probing Gingival Index. The heterogeneity found in these meta-analyses for short term trials was caused by one trial that had exceptionally low standard deviations. Sensitivity analyses revealed the results to be robust when selecting trials of high quality. There was no evidence of any publication bias. No other powered brush designs were consistently superior to manual toothbrushes. In these trials, data on cost, reliability and side effects were inconsistently reported. Those side effects that were reported on in the trials were localised and temporary.

REVIEWER'S CONCLUSIONS

Powered toothbrushes with a rotation oscillation action achieve a modest reduction in plaque and gingivitis compared to manual toothbrushing. Observation of methodological guidelines and greater standardisation of design would benefit both future trials and meta-analyses.

Radiographic determinants of implant performance

This paper reviews and compares the strengths and weaknesses of radiographic techniques including periapical, occlusal, panoramic, direct digital, motion tomography, and computed tomography. Practical considerations for each method, including availability and accessibility, are discussed. To date, digital subtraction radiography is the most versatile and sensitive method for measuring boss loss. It can detect both bone height and bone mass changes on root-form or blade-form dental implants. Criteria for implant success have changed substantially over the past two decades. In clinical trials of dental implants, the outcomes require certain radiographic analyses to address the hypothesis or clinical question adequately. Radiographic methods best suited to the objective assessment of implant performance and hypothesis were reviewed.

Design and implementation of clinical trials of antimicrobial drugs and devices used in periodontal disease treatment

The design and implementation of clinical trials (CTs) carried out to evaluate antimicrobial and anti-infective drugs and devices are one of the most difficult challenges in contemporary periodontal research and product development. The overwhelming amount of evidence which has established a microbial etiology for periodontitis is the basis for developing and testing antimicrobial treatments. Well-designed antimicrobial CTs start with a carefully crafted hypothesis and a protocol which explicitly integrates the requirements of the patient, the clinician, the sponsor, and regulatory authorities. Surrogate variables for effectiveness must be clinically relevant, scientifically sound, and statistically valid. Currently, clinical attachment level measurements and alveolar bone assessments are accepted as proof of effectiveness. Indication and claim support of the antimicrobial product guide the design and implementation of the CT. Adverse microbiologic consequences, such as lack of antimicrobial susceptibility, wrong spectrum, incorrect dosage, non-compliance, and drug interference, must be monitored. Successful CTs balance a large group of variables used to screen, randomize, and assign subjects to experimental and control groups to ensure that prognostic and risk factors are properly accounted for.

Design principles and statistical considerations in periodontal clinical trials

Although clinical trials are a small subset of conducted biomedical research, they have become powerful investigational tools for the evaluation and approval of new treatments by clinician groups and regulatory agencies like the US Food and Drug Administration. To impact the delivery of care, trials in general must meet three criteria: clarity, comparability, and generalizability. Accordingly, trials can offer meaningful data if they have procedures which are well defined and subjects who represent a reasonably homogeneous population. The evaluation of periodontitis interventions presents several challenges due to the disease's heterogeneity and its irregular, episodic pattern; nevertheless, the intent of these novel interventions is to prevent, diagnose, inhibit, or reverse periodontal disease progression. Careful consideration of the trial's objectives should dictate clinical endpoints (primary and surrogate), comparison groups (placebo, standard therapy, test therapy), and equivalence versus superiority as the basis for conclusions. Several design elements such as control population specification, randomization, masking, sample size calculation, and standardization of procedures for patient care and assessment can decrease potential bias and variability. In both parallel and paired (split-mouth) design trials, multiplicities of endpoints, treatments, and subgroups require strategies which address the broader scope of chance findings without excessive loss of study power. Also, the longitudinal assessment of multiple periodontal sites within patients produces correlated data structures for which analytic methods need to account for the appropriate sampling unit. With these design and analytic elements, clinical trials can provide important evidence to investigators, patients, and governmental agencies for the introduction of novel interventions in periodontal practice.

Design and analytic concepts for periodontal clinical trials

Aspects of the design and analysis of periodontal clinical trials are surveyed from a biostatistical perspective. Design issues discussed include protocol preparation, subject selection and its documentation, randomization, problems associated with the sample versus population paradigm in sampling of microbes and gingival fluid constituents, quality control, cross-over and split-mouth versus parallel-arm designs, blinding, and multicenter trials. Analytic discussion deals with the definition and choice of analytic unit, appropriate methods for the analysis of data from multiple sites within the same subject, the nature and application of randomization tests, interim analyses, subgroup analyses, and multiple comparison issues. Examples are provided to illustrate the feasibility of analyzing site-specific data while accounting for intra-subject correlation, which represents the increased similarity of sites chosen from the same mouth as compared to sites from different patients.