GAP Australasian-Dentist Issue 80 Jul-Aug 19

Category 60 AustrÀlÀsiÀn Dentist Àsolated white blemishes (Fig. 5a), can be aesthetically challenging for the young child and tooth bleaching or whitening is a simple way to eradicate these unsightly markings on the teeth. Àhis may need to be followed by microabrasion or resin infiltration. Àn the patient illustrated in Figures 5a and b, a combination of bleaching using custom tray applied 10% carbamide peroxide followed by resin infiltration was used to successfully to eradicate the white blemishes on the central incisors (Fig. 5b). Original white spots may become more noticeable during bleaching treatment, as seen in Figure 1c. Àhis is due to the bleaching material penetrating the weakest part of the enamel first, which is often the white spot. Àhis commonly occurs during the first few days and is referred to as the ‘splotchy stage’ of bleaching. 40 Àhe patient must be urged to persevere with the bleaching treatment to allow time for the bleaching material to dissipate equally throughout the enamel and allow efficient lightening of the background. Àhe ‘splotchy stage’ must be described to the patient before treatment. Àhis is essential for informed consent and to ensure compliance. 41 White spots that are present following completion of bleaching treatment may become less noticeable two weeks post treatment, as oxygen dissipates from the tooth and especially the white spot defect, however further treatment may be required to mask the defect. 34 Brown and yellow staining Àsolated yellow and brown stains result from numerous aetiologies. 12 Fluorosis may result in brown blemishes as seen in Figures 1a, 1b and 1c. Brown stains can be removed 80% of the time by bleaching alone and as such, should be the first line of treatment for such conditions. 42 Cases where bleaching does not completely remove brown staining should utilise additional microabrasion and bonding procedures. 43 Coronal defects Coronal defects can present as discrepancies in tooth shape, size, position, proportion, shade and number. Bleaching often forms an integral part in management of aesthetics and can reduce the need for invasive restorations in the management of such cases. Ào better is this illustrated in use of bleaching, bonding and orthodontics as compared to the use of porcelain veneers and crowns. Furthermore, the use of bleaching to lighten the value of a tooth can reduce the requirement for excessive reduction required for indirect restorations to n aÀ mask discolouration appropriately. Àhis enables the use of more translucent, multi-chromatic restorations, thus improving the outcome of such treatment modalities. Validation of bleaching in such circumstances is particularly noted in severe tetracycline discolouration. Bleaching material can also improve the longevity of restorations in the anterior region, which may be failing due to exposure of restorative margins or due to discolouration of underlying tooth structure. Although bleaching materials have no effect on porcelain, they can successfully penetrate and bleach tooth structure beneath porcelain veneers. 44 As is true for all bleaching cases, further restorative treatment should be delayed for at least two weeks following the completion of bleaching. Bond strength to composites is reduced by 25–50% during bleaching, 45 however, returns to normal two weeks following treatment. Àhis results from oxygen, in the enamel because of the bleaching material, inhibiting the set of resin tags in etched enamel. Over a two-week period, the oxygen dissipates out of the enamel thus returning bond strength to normal. Oxygen present in enamel can also lead to incorrect shade taking and thus, shade taking should also be delayed by at least two weeks and up to six weeks in cases whereby exact shade matching is at a premium. Molar incisor hypomineralisation (MIH) MÀH lesions often present as demarcated enamel opacities ranging in colour from creamy white to yellow/brown, as seen in Figure 6. Àt is well documented that children with MÀH may suffer from a reluctance to smile or a lack of confidence due to the appearance of their teeth and thus may require treatment early to prevent this. 46 Bleaching has been reported to produce some improvement in MÀH patients, especially with the yellow brown discoloured defects. 47 Àeeth affected by MÀH show inflammatory changes within the pulp 48 and as a result, sensitivity is more common among this group of patients. Àherefore, adequate sensitivity prevention before undertaking bleaching treatment is required. Hereditary factors Àeveral hereditary conditions can lead to white blemishes and white discolouration of teeth. Àhesemarkings can be generalised for example in amelogenesis imperfecta (AÀ) patients (Fig. 7) or there can be a single isolated white mark or white blemish on a tooth. Depending on the severity, tooth whitening can be undertaken as the first option for this group of patients. Hereditary conditions associated with defects in enamel and dentine include: 1.À Hereditary conditions associated with Fig. 7 Labial view of a patient with a discoloured dentition where the diagnosis is one of amelogenesis Fig. 8 a and b) Discoloured upper left central incisor in a 13-year-old child following trauma with an aesthetic result following bleaching a b