With thorough treatment planning and careful consideration of restorative material to use, clinicians can successfully address the high aesthetic needs and functional demands of restoring anterior teeth particularly in a mid-mixed dentition state.
By Dr Clarence Tam
A healthy 11-year-old male presented on referral to the practice with a chief concern of unstable and irregular composite restorations affecting his maxillary central incisors. The teeth were initially described in a classic molar-incisor hypomineralisation pattern with an uncavitated, brown hypomineralisation lesion localised to tooth 11 and tooth 21MI status post uncomplicated enamel fracture secondary to impact with a metal drink bottle (Fig. 1). The patient was described as being in a mid-mixed dentition state.
Aesthetic treatment options were outlined, including the possibility of pre-prosthetic whitening, which was refused by the parents after learning that further whitening procedures would need to likely be completed in the future as the remaining secondary teeth erupted intraorally, with the risk of colour variance on bleached teeth. Whitening acts to decrease the chromatic aspects of the hypomineralised lesions and simultaneously lifts the value of the background shade, decreasing the visual contrast between lesion and tooth.
Resin infiltration is always an option for uncavitated hypomineralised lesions, however, with residual composite covering the teeth, structural deficits from trauma and the presence of chromatic regions within the area of organic-rich hypomineralisation, a conservative reductive approach was elected, both to increase the predictability of bonding in the region and to visually eliminate the lesion of interest.
Shade selection was completed prior to the application of an 18% benzocaine/2% tetracaine-based topical anaesthetic (Zap, Germiphene, Brantford, ON, Canada). Dehydration decreases the water content, which increases the proportionate amount of air in a tooth, decreasing the refractive index from 1.33 (water) to 1.00 (air) thereby increasing the reflective index, and thus the visual value and opacity (Fig. 2).
Empress Direct (Ivoclar Vivadent, Schaan) composite shade buttons were selected and placed overlapping the incisal region of tooth 22, which functioned as the colour reference tooth. Corresponding dentin shades were placed cervically, where the enamel was thinnest and the dentin hue most appreciable. A marked halo and sub halo translucency was noted as part of the colour map. An enamel shade of A1 and a dentin shade of A2 was selected for the case (Fig. 3).
Following topical anaesthesia application for 90 seconds and buccal infiltration of 1.4 carpules of a 2% Lignocaine with 1:100,000 epinephrine solution (Septodont), the region was isolated with a split rubber dam with clamp anchors on the upper E’s (Fig. 4). The old restorative material was removed, and the hypomineralised region was conservatively reduced to expose an improved amount of inorganic substrate for bonding.
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