PEARLS

Subjects were randomly divided into three groups of 30 subjects each, depending on the type of electric toothbrush used. The three models were selected for study because they have different operational designs:

1. The Sonicare^*** is a sonic toothbrush operating at 260Hz or 31,000 brush strokes per minute. It has a rectangular brush head with tufts of different lengths. The Sonicare has a built-in timer that turns it off after two minutes of brushing, and a Quadpacer feature that beeps at 30-second intervals to equalize the brushing time in all four quadrants.

2. The Braun Oral-B Ultra^† is an oscillating toothbrush that operates at 7,600 brush strokes per minute (63Hz). The brush head is round and cup-shaped.

3. The Rota-Dent^‡ is a rotary toothbrush with a small tip for brushing individual teeth. Three different attachments can be used with the brush: a cup; a short, pointed head; and an elongated head. The short, pointed head was used in this study to improve access around the orthodontic brackets.

Each subject was given one of the electric toothbrushes and instructed on proper use, according to the manufacturer's instructions. Patients were told to brush twice a day for two minutes each time, using Crest mint gel toothpaste^††. Subjects in the Sonicare group used the toothbrush's built-in timer; those in the Braun Oral-B and Rota-Dent groups were given electronic timers. Brushing logs were provided so that the patients could record when they used their toothbrushes.

The patients were seen every three to five weeks, depending on their individual orthodontic needs. All subjects were examined at months one, two, three, and six. The brush heads for all toothbrushes were replaced at the three-month examinations.

The teeth included in the study were the central and lateral incisors and canines in all four quadrants. All these teeth were checked at each visit, and the sites of any bond failures or brackets no longer adhering to the tooth surfaces were noted and recorded, along with the causes of failure. Replacement brackets were bonded using the same materials and procedures.

Subjects paid the usual clinic fees for their orthodontic therapy. After six months, each patient received $50 for completing the study.

Results

Of the 1,080 total brackets, only 12 were lost due to occlusal trauma or patient-reported incidents (Table 1). No bracket failures were reported from toothbrushing.

Discussion

Debonding of orthodontic brackets can be caused by improper technique.^7,8 Bond failure can occur if the resin is not cured properly, and if the bracket is not aligned properly within the brief setting time, there will be more stress on the bracket once the wire is placed.⁹ In this study, a proven bonding adhesive was used to minimize technical errors. In fact, all the bond failures that occurred during the study were due to repetitive chewing habits of the patients.

A recent in vitro study compared the Sonicare and Interplak electric toothbrushes' effects on the bond strength of orthodontic brackets to a control group.¹⁰ After the teeth were brushed mechanically to simulate two years of patient brushing, the force required to debond the brackets was measured. The authors concluded that both electric toothbrushes caused a decrease in bond strength, but were unsure whether this would have clinical relevance in terms of the brackets becoming loose over time.

The present study, on the other hand, was designed to evaluate the effects of three electric toothbrushes in typical orthodontic treatment, exposing the brackets to normal orofacial musculature and to masticatory and orthodontic forces. Although none of the brackets was lost in brushing, one might question whether the brushes contributed in some way to the eventual debonding.