PubMed · 1622595
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W G Dickerson. Eliminating sensitive composites.. https://pubmed.ncbi.nlm.nih.gov/1622595/
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The enamel surface layer of some human teeth was treated with the low-energy Nd:YAG laser at 8 mJ pulse energy. These samples were previously etched with 0.05 M orthophosphoric acid to reduce the surface reflection. The treated samples, as well as the control samples, were widely studied by scanning electron microscopy, and, in the lased group, significant morphologic changes affecting the enamel surface were observed. Those changes reveal principally the loss of the typical surface structure of the acid-etched enamel. The hydroxyapatite prisms were not discernible, and there was a decrease in the roughness of the lased surface enamel. These laser-induced structural changes may be related to the increased resistance to the calcification reported by many authors.
Current interest in the use of layers in clinical dentistry has suggested that this technique may be applicable to enamel etching in orthodontics. A pulsed Nd:YAG laser was used to etch the enamel surfaces of teeth in vivo prior to the bonding of orthodontic brackets with composite resin. Overall laser bonding took considerably longer, was less reliable in terms of bond strength, and produced more discomfort than conventional acid etching. The use of the ND:YAG laser for etching teeth prior to bonding orthodontic brackets is not recommended.
This in vitro study investigated the effect of dental surface treatments on the seal of porcelain and resin laminate veneers to tooth structure. Nine groups of 20 teeth were prepared for labial veneers--six groups with the apical margin of the veneer in dentin, two groups with the veneer wholly bordered by enamel, and one group with the apical margin coincident with the apical margin of a previously placed glass ionomer restoration. The teeth were treated with a variety of dentin-bonding agents prior to restoration of eight groups with porcelain veneers and one group with Visio-Gem microfilled resin veneers. After placement, the veneers were stored in water for 4 days, then subjected to thermocycling before silver staining and sectioning. Results showed no leakage around the margins of the veneers wholly bordered by enamel. Complete leakage was found around the glass ionomer restorations, and nearly total leakage was found along the resin-dentin interface of the resin veneers. The porcelain veneers that extended onto dentin showed variable but limited leakage for four of five of the dentin-bonding treatments.