Maxillary molar intrusion using mini-implants in the anterior palate – “Mousetrap” versus “Mini-Mousetrap”

Abstract

Supra-erupted maxillary molar teeth pose a major restorative challenge when attempting to prosthetically rehabilitate a partially edentulous mandibular dental arch. Traditional approaches with conventional tooth-borne appliances usually entail undesirable side-effects, including extrusion of adjacent teeth. Temporary anchorage devices (TADs), often inserted in the alveolar process, should help to minimize this phenomenon. The interradicular placement of mini-implants positioned between the roots of the maxillary molars has a number of inherent disadvantages and limitations. The preferred site for insertion of mini-implants is the anterior palate, which ensures a low risk of failure and mini-implant fracture. The ‘Mousetrap’ appliance is comprised of two mini-implants in the anterior palate, with attached lever arms for molar intrusion and a transpalatal arch (TPA) to avoid unwanted palatal tipping of the molar to be intruded. The ‘Mini-Mousetrap’ appliance was designed as a pared-down version without a TPA. If a TPA is not used, molar movement must be closely monitored, and the line of force action may need modification in order to minimize unwanted molar tipping.