Which methods for polishing glass ceramics show better performance? A literature review

This summary is based on the article published in the Journal of Prosthodontic Research: Polishing for glass ceramics: Which protocol? (July 2014)

• Taˆ nia Mara da Silva DDS, MD student
• Ana Carolina Rodrigues Danzi Salvia DDS, MD
• Rodrigo Furtado de Carvalho DDS, MD
• Clovis Pagani DDS, MD, PhD
• Daniel Maranha da Rocha DDS, MD, PhD
• Eduardo Galera da Silva DDS, MD, PhD

Context

• By working with ceramic restorations, the dentist often needs to perform clinical adjustments through wear by diamond burs, consequently removing the superficial glazing layer.
• These adjustments are needed when the restoration exhibits premature occlusal contacts and/or inadequate contours (1–3).
• The rupture of the glazing layer increases the superficial roughness, leading to clinical problems: weariness of the antagonist tooth (4); retention of microbial biofilm (5) and inflammation of the periodontal tissues; staining (6); unsatisfactory esthetics [7] and smaller resistance to cracks propagation (2, 8, 9).
• Because of these aforementioned reasons, the researchers have stated the use of a reglazing process (10) or polishing of the ceramic restorations (11) as alternatives which result in a greater superficial smoothness.
• Different alternative polishing techniques have been described for ceramic restorations (9, 12, 13) and several polishing kits are available into dental market.
• The effect on the superficial roughness generated by the different adjustment [10] protocols followed by the polishing of ceramic restorations is of great interest for the dentist and the superficial roughness have been studied by several researchers (2, 3, 14, 15, 9, 16, 17, 12, 18).

Purpose of the Article 

To present methods of polishing showing better performance.

Key Findings

• After the rupture of the glazing layer due to the adjustments of the restorations, the best choice for the polishing of the surface will depend on the type of ceramics used.
• The glazing procedure provide excellent results regarding to the superficial smoothness; however, if reglazing is impossible, either abrasive rubber cups/points or sandpapaer discs followed by the use of diamond polishing pastes results in a satisfactory superficial smoothness.
• Clinical studies that take into account the behavior of the protocols polishing are scarce and should be encouraged.
• The large number of variables that influence the final outcome of polishing should be considered. This study demonstrated the need for greater standardization of methodologies, enabling a comparison between researches.

References

1. Al-Wahadni A, Martin DM. Glazing and finishing dental porcelain: a literature review. J Can Dent Assoc
2. 1998;64:580–3.
3. Sarikaya I, Gu¨ ler AU. Effects of different polishing techniques on the surface roughness of dental porcelains. J Appl Oral Sci 2010;18:10–6.
4. Wang F, Chen JH, Wang H. Surface roughness of a novel dental porcelain following different polishing procedures. Int J Prosthodont 2009;22:178–80.
5. Monasky GE, Taylor DF. Studies on the wear of porcelain, enamel, and gold. J Prosthet Dent 1971;25:299–306.
6. Queiroz JR, Fissmer SF, Koga-Ito CY, Salvia ACRD, Massi M, Sobrinho AS, et al. Effect of diamond-like carbon thin film coated acrylic resin on Candida albicans biofilm formation. J Prosthodont 2013;10:120–9.
7. Haywood VB, Heymann HO, Scurria MS. Effects of water, speed, and experimental instrumentation on finishing and polishing porcelain intra-orally. Dent Mater 1989;5:185–8.
8. Haywood VB, Heymann HO, Kusy RP, Whitley JQ, Andreaus SB. Polishing porcelain veneers: an SEM and specular reflectance analysis. Dent Mater 1988;4:116–21.
9. Anusavice KJ, Lee RB. Effect of firing temperature and water exposure on crack propagation in unglazed porcelain. J Dent Res 1989;68:1075–81.
10. Flury S, Lussi A, Zimmerli B. Performance of different polishing techniques for direct CAD/CAM ceramic restorations. Oper Dent 2010;35:470–81.
11. Newitter DA, Schlissel ER, Wolff MS. An evaluation of adjustment and postadjustment finishing techniques on the surface of porcelain-bonded-to-metal crowns. J Prosthet Dent 1982;48:388–95.
12. Patterson CJ, McLundie AC, Stirrups DR, Taylor WG. Refinishing of porcelain by using a refinishing kit. J Prosthet Dent 1991;65:383–8.
13. Karan S, Toroglu MS. Porcelain refinishing with two different polishing systems after orthodontic debonding. Angle Orthod 2008;78:947–53.
14. Dalkiz M, Sipahi C, Beydemir B. Effects of six surface treatment methods on the surface roughness of a lowfusing and an ultra low-fusing feldspathic ceramic material. J Prosthodont 2009;18:217–22.
15. Yilmaz K, Ozkan P. Profilometer evaluation of the effect of various polishing methods on the surface roughness in dental ceramics of different structures subjected to repeated firings. Quintessence Int 2010;41:125–31.
16. Bottino MC, Valandro LF, Kantorski KZ, Bressiani JC, Bottino MA. Polishing methods of an alumina-reinforced feldspar ceramic. Braz Dent J 2006;17:285–9.
17. Werneck RD, Neisser MP. Surface roughness of a feldspathic dental porcelain after simulation of occlusal adjustment and polishing. Rev Odont Cieˆnc 2008;23:166–9.
18. Scota AGP, Spohr AM. Effect of two mechanical polishing systems on surface roughness of feldsphatic ceramics. Braz Dent Sci 2010;13:45–51.

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