Oral-B makes quite a few different models; I think Gordon was referring to the oscillating rotation ones, which according to a Cochrane meta-analysis of studies did the best job (abstract follows):
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Manual versus powered toothbrushing for oral health
Robinson PG, Deacon SA, Deery C, Heanue M, Walmsley AD, Worthington HV, Glenny AM, Shaw WC
Summary
When compared to manual toothbrushes, powered toothbrushes with a rotation oscillation action provide protection against gum inflammation in the long and short term and better plaque removal in the short term
Removing dental plaque by toothbrushing helps prevent gum inflammation (gingivitis). Toothbrushing with a fluoride toothpaste prevents tooth decay.
Powered toothbrushes simulate manual toothbrushing in different ways (such as moving side to side or circular motions). The review of trials found that only rotation oscillation (where brush heads rotate in one direction and then the other) is better than manual toothbrushes at removing plaque and reducing gum inflammation, and is no more likely to cause injuries to gums. Long- term benefits of this for dental health are unclear.
This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2008 Issue 1, Copyright © 2008 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in
The Cochrane Library (ISSN 1464-780X).
This record should be cited as: Robinson PG, Deacon SA, Deery C, Heanue M, Walmsley AD, Worthington HV, Glenny AM, Shaw WC. Manual versus powered toothbrushing for oral health.
Cochrane Database of Systematic Reviews 2003, Issue 1. Art. No.: CD002281. DOI: 10.1002/14651858.CD002281.pub2
This version first published online: January 20. 2003
Date of last subtantive update: February 17. 2005
Abstract
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 Löe 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.
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It's quite possible that the Sonicare is just as good, but the studies they cite aren't that well-controlled or large enough and not always in vivo.
People tend to have quite strong preferences on either Oral-B (the professional series now corresponds to what used to be called their 3D range) or Sonicare. Personally I prefer Oral-B due to the smaller brush-head, but I suppose it may depend on the shape of your jaw. It's probably best to go with a toothbrush you find comfortable, as you'll be more likely to use it

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