Orthofile®: a new approach for mechanical interproximal reduction : a scanning electron microscopic enamel evaluation

The aim of this in vitro study was to evaluate the stripping achieved on different teeth (incisors, canines, and premolars) by two grades of abrasive strips used for the first and tenth time. Our second aim was to test the efficacy of these strips by calculating the time necessary to perform interproximal reductions of 0.10, 0.20, and 0.30 mm.

Four models were constructed using extracted teeth affixed in wax. The upper and lower arches were set on plaster bases and fixed in wax, carefully creating contact points. All model mouths were treated with artificial saliva (Oral Balance®) in order to simulate the biological conditions in the oral cavity. We then tested specific air-rotor strips of different grades and degrees of wear (15-µm-grain and 25-µm-grain Orthofile® strips). Afterwards the teeth from all samples were cut lengthwise in half, and each mesial and distal portion was gold-plated and observed under SEM at incremental magnification (30, 60, and 100 µm).

The 25-µm-grain strip was more effective than the 15-µm-grain strip, irrespective of the tooth involved. Second, the finishing phase with specific polishing strips after interproximal reduction was fundamental in reducing the number of abrasions and irregularities created by stripping, in particular after using the 25-µm-grain strip. To achieve the best result, the entire abraded area must be polished.

This system permits a rapid and effective stripping procedure in direct proportion to the strip's grain and in inverse proportion to the wear from its use. Further research will enable us to compare this system with similar procedures.