Effect of brushing with sonic and counterrotational toothbrushes on the bond strength of orthodontic brackets

Influence of tooth brushing on adhesion strength of orthodontic brackets bonded to porcelain

BACKGROUND

Adhesive resin composite, which is used to bond orthodontic bracket to tooth surface is exposed to the influence of wear by tooth brushing and wear may influence loosening of the bracket.

OBJECTIVE

The aim of this study was to evaluate in vitro the effect of tooth brushing on the adhesion strength of orthodontic brackets bonded to surface treated porcelain.

METHOD

A total of 90 glazed porcelain fused to metal facets (PFM) were randomly assigned into 3 groups according to the surface treatment to be received. Group 1 was conditioned with hydrofluoric acid (HF), group 2 conditioned with grit-blasting (GB) and group 3 conditioned with tribochemical silica coating (RC). The groups were evaluated for surface roughness (Ra) before and after surface treatment. Next, 15 samples from each group were subjected to brushing and remaining 15 samples served as the baseline (n=15). Adhesion strength (shear bond strength)was recorded using a universal testing machine. Data collected were analyzed by ANOVA and Tukey's multiple comparison post hoc analysis.

RESULTS

Tooth brushing decreased the bond strength in all groups. The highest adhesion strength (baseline and after brushing) was observed in group 3 (26.8 ± 1.77 MPa and 23.57 ± 1.02 MPa) and the lowest was found in group 1 (9.6 ± 1.5 MPa and 5.87 ± 0.77 MPa). Group 3 specimens exhibited the highest Ra (1.24 ± 0.08).

CONCLUSION

It was found that tooth brushing of the exposed adhesive resin composite at the bracket-bonding substrate interface lowers the bonding strength regardless of the surface treatment of the substrate.

Effect of Disinfection on the Bond Strength between Denture Teeth and Microwave-Cured Acrylic Resin Denture Base

PURPOSE

Denture tooth debonding is a common complication for denture wearers; however, the effect of complete denture disinfection on bonding between denture teeth and acrylic resin remains unclear. The aim of this study was to evaluate the effect of disinfection methods on the bond strength between denture teeth and microwave-cured acrylic resin denture base.

MATERIALS AND METHODS

Three commercial brands of denture teeth (Trilux, Biolux, Vipi Dent Plus) and one microwave-cured acrylic resin denture base were tested. Each brand of denture teeth was divided into seven groups (n = 6; estimated by partial Eta squared). The specimenss of groups H and Cl were immersed in 1% sodium hypochlorite and 4% chlorhexidine digluconate for 7 days, respectively. In group Br, the specimens were subjected to toothbrush simulation under 200 g of force for 20,000 cycles. In groups Br-H and Br-Cl, the specimens were brushed and further disinfected with 1% sodium hypochlorite and 4% chlorhexidine digluconate, respectively. In control groups 1 (Co1) and 2 (Co2), the specimens were stored in distilled water for 50 ± 2 hours and 7 days, respectively. Shear bond strength testing was performed at the resin/tooth interface in a universal testing machine at a 1 mm/min crosshead speed. The failure pattern was quantified and classified into adhesive, cohesive, or mixed. Data were analyzed using two-way ANOVA and Tukey HSD test (α = 0.05).

RESULTS

Disinfection with 1% sodium hypochlorite (p = 0.031), brushing (p < 0.0001), and association of brushing with either 1% sodium hypochlorite (p < 0.0001) or 4% chlorhexidine digluconate (p = 0.01) reduced the bond strength between denture teeth and microwave-cured acrylic resin denture base. All commercial brands of denture teeth presented a similar bond strength (p > 0.05). The failure pattern was predominantly adhesive independent of the disinfection method and denture tooth brand.

CONCLUSIONS

Disinfection with sodium hypochlorite, brushing, and the association of mechanical and chemical methods reduced the bond strength between denture tooth and microwave-cured acrylic resin denture base.

Comparison of manual versus sonic and ultrasonic toothbrushes: a review

PURPOSE

This review of the literature intends to evaluate the effect of brushes with high frequency motion when compared with manual toothbrushes regarding the indices of plaque and gingival bleeding.

METHODS

Patients presenting gingivitis and/or chronic periodontitis were evaluated in addition to patients having osseointegrated implants and fixed orthodontic appliances. Pertinent literature was reviewed to select articles according to previously defined inclusion criteria.

RESULTS

In the assessed studies results showed significant decreases in plaque and gingival indices by utilization of both types of brushes. However, in the selected studies where sonic brushes were tested in orthodontic and dental implant patients there was a more significant decrease in the indices. Furthermore, there was no indication of gingival recession attributed to product use.

CONCLUSION

Future studies with a more homogeneous methodology and better experiment designs will be needed.

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.