Effect of the Electric Toothbrush on Human Gingiva: Histologic and Microrespirometer Evaluation

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.

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.

Alveolar bone resorption following coronal versus apical approach in a mucoperiosteal flap surgery procedure in the rat mandible

BACKGROUND

In several publications, we have reported that a distinct resorptive phase of alveolar bone developed during 3 weeks following elevation of a mucoperiosteal flap in rats by a coronal surgical approach. In the present study, we compared the alveolar bone loss after mucoperiosteal flap surgery by a coronal approach (COR) to a surgical approach incising the mucosa close to the tooth apices and separating the mucoperiosteum toward the tooth crown (apical approach, AP).

METHODS

Eighteen Wistar rats were divided into 2 experimental groups; each group consisted of 9 rats. In the first group, COR was performed on both buccal and lingual aspects on the right side of the rat mandible, while the left side served as a sham-operated control. In the second experimental group, AP was performed.

RESULTS

In the AP group, the outer aspect (buccal or lingual) of the alveolar bone was slightly resorbed usually at the level where the mucosa was incised. In many sections, extensive modeling of new trabecular bone was seen, coronal to the surgical incision. On the contrary, the coronal surgical approach revealed an extensive resorptive phase, mainly of the periodontal aspect of the alveolar bone.

CONCLUSIONS

The results of this study show that periodontal surgery by a coronal surgical approach stimulates a burst of remodeling of the alveolar bone in a very specific pattern.

Effect of mechanical stimulation by tooth brushing on oxygen tension in dog gingiva

To determine oxygen tension (pO2) in gingival tissue, an oxygen micro-electrode with a membrane-coated Pt needle was inserted into the gingiva of 12 dogs. Teeth were brushed using a modified Bass technique for 10 s under 200 g pressure. pO2 increased and reached a maximum 15 min after brushing, then gradually returned to the baseline. A significant increase in pO2 persisted for approx. 1 h. These findings suggest that short-term stimulation by tooth brushing increases oxygen tension in the gingiva.

Mechanical stimulation by toothbrushing increases oxygen sufficiency in human gingivae

We studied the immediate effect of mechanical stimulation with a toothbrush on oxygen sufficiency in human gingivae. Teeth were brushed with a modified Bass technique at various forces (100, 200, and 300 g) for various times (5, 10, and 30 s). Hemoglobin (Hb) oxygen saturation was measured before and intermittently for 60 min after brushing, by non-invasive tissue reflectance spectrophotometry. Hb oxygen saturation increased within a few min after brushing and then slowly returned to the initial level. Toothbrushing at 200 g for 10 s caused the longest-lived increase in Hb oxygen saturation; saturation remained about 6% above the baseline level for more than 25 min. Before brushing, Hb oxygen saturation was significantly lower in inflamed gingivae than in healthy gingivae (p < 0.05). After brushing of inflamed gingivae, the Hb oxygen saturation almost reached the level measured in healthy gingivae before brushing. These findings suggest that stimulation with a toothbrush increases oxygen sufficiency in both healthy and inflamed gingivae.

Histologic evaluation of the effects of intrasulcular toothbrushing on human sulcular epithelium

Nineteen young adult Caucasian males had an average Gingival Index Score of 0.47. Each was asked to demonstrate his present method of toothbrushing: thirteen used the scrub method, and six combined the scrub and roll methods. Control gingival tissue specimens were taken from the mandibular left first bicuspid or first molar regions, and the area was allowed to heal for 40 days. Following complete healing, intrasulcular brushing was used in the mandibular left posterior segment, for 30 seconds daily for a period of 40 days. The brushing was done by the investigator on 28 days and by the subjects on 12 days. The average Gingival Index Score following intrasulcular brushing was 0.25. A gingival specimen was taken from the experimental area of the mandibular left second bicuspid region. Histological findings in control specimens from 13 subjects showed parakeratinization for varying distances in the sulcus epithelium apical to the gingival crest. In six specimens a complete absence of sulcus keratinization was observed. The average Inflammatory Index Score was 1.21. Following intrasculcular brushing, 18 specimens showed a parakeratin layer apical to the gingival crest; in 14, it extended the entire length of the coronal sulcular epithelium or apparent clinical sulcus, whereas in four more it extended well beyond the gingival crest into the sulcus. In the six subjects whose control specimens showed an absence of keratin apical to the gingival crest, parakeratinization of part or all of the clinical sulcus was found following intrasulcular brushing. The average Inflammatory Index Score was 1.015. A moderately intense acute inflammatory reaction was observed within the attachment epithelium in three subjects. Possible therapeutic benefits and hazards of intrasulcular brushing are discussed.