Читать книгу Periodontics - Fernando Suarez - Страница 108

The periodontium can be affected by the different types and surface characteristics (eg, surface free energy and roughness) of dental materials.^194–197 In a comparative study by Chan and Weber,¹⁹⁸ 150 crowns (50 porcelain crowns with aluminum-oxide framework, 68 porcelain-fused-to-metal [PFM] restorations, 13 cast gold crowns, 19 acrylic resin veneer crowns) and 242 intact natural teeth serving as controls were compared in terms of plaque retention using Löe and Silness¹⁹⁹ plaque index scores in a crown-to-quadrant ratio. Results showed that crowns with an aluminum-oxide base had minor plaque retention (32%), whereas PFM crowns (90%), natural teeth (110%), cast gold restorations (148%), and acrylic resin veneer crowns (152%) had substantially more plaque retention. Other material surfaces, like lithium disilicate and zirconia, have shown a superior resistance to surface roughness changes after instrumentation with stainless steel curettes, yet zirconia revealed a greater bacterial adhesion compared with gold alloy and lithium disilicate.²⁰⁰

Despite differences in plaque retention and quality of the marginal fit, galvanic-ceramic crowns demonstrated significantly less clinical and inflammatory responses than metallic-ceramic crowns by means of plaque index, gingival index, gingival crevicular fluid flow rate, and levels of immunoglobulin G.²⁰¹ Nonetheless, these responses might differ when ceramic or metal restorations are compared with resin-bonded restorations. A study by van Dijken and Sjöström tested the effects of glass ionomer cement and composite filling materials for Class V subgingival cervical lesions and demonstrated that these materials present with no differences over time in term of the amount of plaque and degree of gingivitis when compared with enamel.²⁰² Konradsson et al noted a similar inflammatory biomarker response (interleukin [IL] 1α, IL-1β, and IL-1 receptor antagonist) with different materials when compared with enamel.²⁰³

It has been proposed that a maximum roughness threshold of Ra less than 0.2 μm be recommended to reduce plaque accumulation.²⁰⁴ Moreover, periodontal therapy might have an impact in roughness changes, resulting in increased plaque accumulation. These changes are also dependent on each dental material and treatment modality.²⁰⁵ An in vitro study using gold alloy specimens showed that pre- and posttreatment Ra values significantly increased after instrumentation with stainless steel curettes and prophylactic cups.²⁰⁰ Interestingly, stainless steel curettes increase roughness levels nearly 13 times greater than prophylactic cups.

Proceedings from the 2017 World Workshop on the classification of Periodontal and Peri-implant Diseases and Conditions concluded that dental materials act similar to enamel as plaque retentive factors to initiate gingivitis.¹⁹⁷