CATEGORY 92 AUSTRALASIAN DENTIST 2. Secretory Highly organised enamel is laid down. Defect here leads to enamel hypoplasia. 3. Maturation Mineralisation of enamel. Defect here leads to enamel hypomineralisation. Permanent incisor crowns complete development at age three. Any injury before this time damages ameloblasts leading to enamel defects (Table 1(b & c)). Given TDI usually occurs at 0-2 years and coincides with the incisor crown formation, enamel defects (such as hypoplasia) are one of the most prevalent sequelae.7 TDI after radiographically visible complete crown formation (i.e. after the age of three for incisors) can lead to root dilaceration (Table 1E) and enamel discolouration (Table 1(a)); as maturation continues until eruption.8 If trauma corresponds to the maturation phase, ruffle-ended ameloblasts are damaged. Subsequent ameloblast metaplasia to cuboidal or squamous epithelium occurs leading to a reduction in inorganic content.2 As a result a lower mineral content is incorporated into the enamel. Areas of reduced mineralisation have a differing refractive index (1.33 when filled with water compared to 1.62 of sound enamel) and thus clinically appear white.9 If trauma induced bleeding of the surrounding soft tissue occurs (even after cessation of ameloblast activity), the breakdown of haemoglobin will lead to the yellow-brown discolorations incorporating into the enamel.10 Management of minor yellow-to-white opacities may be aesthetically managed with micro-abrasion.8 A by-product of micro-abrasion is the increase in light absorption and thus further reduction in refractive index compared to sound enamel leading to reduced value and increase in chroma shining through the enamel.11 As such, combination of micro-abrasion and extrinsic bleaching may aid break the double bonds of chromophores that give the tooth some of its chroma. Regardless, often TDI caused discolorations span the entire enamel thickness, as such, microabrasion and bleaching combination can lead to the negative amplification of the opaque discolouration. Megabrasion is more clinically reliable; utilising highspeed bur to remove the defective enamel followed by adhesive composite resin restoration.11 In this clinical report the patient desired aesthetic changes to the hypoplastic anteriors but declined orthodontic and orthognathic surgery for correction of the prognathic mandible. Restorative options were thus restricted to direct or indirect veneers. Given adolescence is a crucial LINICAL Stent Advantages: u Time-effective. u More predictable result. u Allows patient approval of outcome prior. u Cure through oxygen-inhibition layer. Disadvantages: u Laboratory fees. u Higher patient cost. u Increased appointment number. Types: i) Lab-made palatal putty stent. ii) Uveneer, with/without the Paladex. iii) Injectable technique. Free-hand Advantages: u Cost-effective. u Ability to instantly tailor to patient feedback. Disadvantages: u Result dependent on operator skills. u Chair-time. Table 2. Direct Veneer Restorative Options Figure 8a. Paladex build-up left central with flowable enamel shade Figure 10a & 10b. Comparison of smile pre-operatively and post-operatively Figure 9a & 9b. Finish and polish Figure 9c. Light reflection post 3M sof-lex Figure 8b. Ivoclar IPS Empress Direct BLL first layer, cured Figure 8c. Uveneer pressed as second layer with same Ivoclar composite Figure 11. Post-operative photographs developmental phase in building confidence, the patient rejected indirect veneers as they contained too many barriers between him and restoring his selfesteem. This included tooth preparation, need for full periodontal maturity, greater number of visits and higher fees. As such, the patient elected for the direct restorative method, which can be conducted in one of three main ways (Table 2):
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