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CDE0111

I 11 clinical technique _ fractured maxillary central incisors I cosmeticdentistry 1_2011 _Step 1: The fractured fragment was carefully removed without damaging the remaining tooth or the fragment (Fig. 38) and hydrated in sterile water for 30 minutes. _Step 2: The silicone index was placed onto the teeth and aided the correct location of the dislodged fragment (Fig. 39). _Step 3: The retraction cord was placed around the right central incisor, and both the remain- ing tooth and fragment were etched and coated with OptiBond Solo Plus. A thin layer of Herculite XRV Ultra Incisal shade was placed into the index to ‘link’ the tooth and fragment and subsequently light-cured. The index was removed, and the position of the fragment verified from both facial and palatal aspects (Figs. 40 & 41). _Step 4: The chasm between the tooth and frag- ment was filled with a combination of Dentine A2 and Enamel A2 shades to create an un- noticeable colour transition (Figs. 42 & 43). _Finishing and polishing The final stage of a composite filling is finish- ing and polishing, which ensures longevity and superior aesthetics. The finishing procedure, which ensures a high gloss and smooth surface roughness (Ra), is important not only to prevent surface discolouration, but also to ensure oral health by reducing plaque accumulation and gingival irritation. Furthermore, polishing is also beneficial for achieving good marginal adapta- tion, reduced micro-leakage and for retaining morphology and occlusal contacts owing to improved wear resistance. The type of inorganic filler, particle size and the degree of loading influence the polishability of a composite. Fur- thermore, the difference in hardness between the resin matrix and filler content and amount of conversion of the polymer also contribute to the degree of surface roughness. Other factors affecting the finish are the flexibility and hardness of the finishing mate- rials, force applied, speed and cooling of rota- ry instruments, and duration of the polishing procedure. However, contemporary light-cured composites with finer particles (for example, nano-filled) and fine grit rotary instruments allow a durable, smooth and high lustre texture to be readily attainable. Although using cellulose acetate matrices or Mylar strips mitigates the finishing procedures, most free-hand composite build-ups usually re- quire finishing and polishing to remove excess composite and alter morphology and occlusion. In addition, the superficial oxygen inhibition layer requires removal to improve the surface hardness of the composite for resilience and im- proved aesthetics. But how smooth is smooth? The degree of micromorphology irregularities to which a filling should be finished is debatable. Some authorities suggest that the microscopic surface irregularities should be smaller than the critical bacterial adhesion threshold of Ra = 0.2 µm, while others state that it should equal the Ra of natural enamel-to-enamel occluding surfaces. Another threshold for smoothness is that in order for a filling surface to appear smooth optically, its Ra value should be less than Fig. 32_The CompoRoller with a conical tip is used to sculpt the surface anatomy. Fig. 33_The CompoRoller with a cylindrical tip is used to sculpt the surface anatomy. Fig. 34_The dentine mamelon effect created by using a dentine shade is clearly visible at the mesial aspect before being covered with an enamel shade overlay. Fig. 35_The completed reconstruction with a thin overlying incisal shade at the incisal third of the build-up. Fig. 36_A week later, the colour of the build-up on the left central incisor is acceptable and ready for finishing and polishing. Fig. 37_Incisal view of the build-up on the left central incisor, one week later. (The cervical gingival margin of the left central incisor shows a trapped cornhusk, which was subsequently removed.) Fig. 33 Fig. 34Fig. 32 Fig. 36 Fig. 37Fig. 35