Evaluation of the effect of different methods of microabrasion and polishing on surface roughness of dental enamel :[PAUTHORS], Indian Journal of Dental Research (IJDR)

ORIGINAL RESEARCH
Year : 2014 | Volume : 25 | Issue : 3 | Page : 290--293

Evaluation of the effect of different methods of microabrasion and polishing on surface roughness of dental enamel

Carlos Bertoldo, Debora Lima, Larissa Fragoso, Glaucia Ambrosano, Flavio Aguiar, Jose Lovadino
Department of Restorative Dentistry, Piracicaba Dental School / University of Campinas, UNICAMP, Brazil

Correspondence Address:
Debora Lima
Department of Restorative Dentistry, Piracicaba Dental School / University of Campinas, UNICAMP
Brazil

Abstract

Description of the Technique: The microabrasion technique of enamel consists of selectively abrading the discolored areas or causing superficial structural changes in a selective way. Objective: In microabrasion technique, abrasive products associated with acids are used, and the evaluation of enamel roughness after this treatment, as well as surface polishing, is necessary. This in-vitro study evaluated the enamel roughness after microabrasion, followed by different polishing techniques. Settings and Design: Roughness analyses were performed before microabrasion (L1), after microabrasion (L2), and after polishing (L3).Thus, 60 bovine incisive teeth divided into two groups were selected (n=30): G1- 37% phosphoric acid (37%) (Dentsply) and pumice; G2- hydrochloric acid (6.6%) associated with silicon carbide (Opalustre - Ultradent). Thereafter, the groups were divided into three sub-groups (n=10), according to the system of polishing: A - Fine and superfine granulation aluminum oxide discs (SofLex 3M); B - Diamond Paste (FGM) associated with felt discs (FGM); C - Silicone tips (Enhance - Dentsply). A PROC MIXED procedure was applied after data exploratory analysis, as well as the Tukey-Kramer test (5%). Results: No statistical differences were found between G1 and G2 groups. L2 differed statistically from L1 and showed superior amounts of roughness. Differences in the amounts of post-polishing roughness for specific groups (1A, 2B, and 1C) arose, which demonstrated less roughness in L3 and differed statistically from L2 in the polishing system. Conclusion: All products increased enamel roughness, and the effectiveness of the polishing systems was dependent upon the abrasive used.

How to cite this article:
Bertoldo C, Lima D, Fragoso L, Ambrosano G, Aguiar F, Lovadino J. Evaluation of the effect of different methods of microabrasion and polishing on surface roughness of dental enamel.Indian J Dent Res 2014;25:290-293

How to cite this URL:
Bertoldo C, Lima D, Fragoso L, Ambrosano G, Aguiar F, Lovadino J. Evaluation of the effect of different methods of microabrasion and polishing on surface roughness of dental enamel. Indian J Dent Res [serial online] 2014 [cited 2023 Sep 29 ];25:290-293
Available from: https://www.ijdr.in/text.asp?2014/25/3/290/138308

Full Text

INTRODUCTION

One of the most challenging aspects of dentistry involves the esthetic resolution of most of the various types of spots present on the dental enamel, which can take on several different colors that affect the esthetics. Such spots may have different depths and ranges of extension, and they can be intrinsic or extrinsic, depending on the etiology.

Basically, the microabrasion technique consists of selectively abrading the discolored areas, giving a healthy clinical aspect to the dilapidated enamel. This technique was described by Croll and Cavanaugh [1] and aimed for the conservative removal of spots from the enamel. The authors were heavily influenced by McCloskey's [2] report, which endorsed the technique invented by Kane (1926), applying 18% hydrochloride acid to cotton pieces, without the use of heat, thereby obtaining satisfactory clinical results. Initially, the microabrasion technique consisted of the application of acids to the surface of the spotted enamel; however, this technique, which depends on abrasive agents, evolved, resulting in a significant advance in its effectiveness.

This technique is linked with the esthetic treatment of fluorosis white spots, [3] inactive white spots by dysmineralization, orthodontic post-treatment, located hypoplasia arising from dental trauma or infection, and idiopathic hypoplasias, in which the discoloration is limited exclusively to the most superficial layer of dental enamel. [4]

Kamp [5] advocated another technical variation, entailing the use of 37% phosphoric acid associated with pumice, for removal of the discoloration from the dental enamel. The use of 37% phosphoric acid is justified with the fact that this acid is more regularly available at dentist offices and is more biologically compatible.

Actually, new variations of this technique arose, involving the re-formulation of acid concentration and of the abrasive. Products based in 6% hydrochloric acid and associated with particles of silicon carbide were launched on the market and further combinations with tooth bleaching techniques with carbamide peroxide improved the results obtained. [6],[7]

The use of a strong acid, besides being dangerous to dentists and patients, [8] may create irregularities on the enamel surface. [9] As for enamel superficial roughness, there continues to be much variation in the results. Chan [10] did not find a significant increase in the amounts of enamel superficial roughness when they used 10% hydrochloric acid associated with silicon carbide as an abrasive agent (Prema Compound/Premier Dental Co.).

Numerous studies have evaluated the effects of microabrasion, and most of them have been performed through microscope evaluations and clinical cases. [11],[12],[13],[14] Despite the benefits of using this technique to remove spots present on superficial enamel, little is known about the undesirable effects that might be occurring. Thus, the purposes of this study were to compare the enamel superficial roughness after microabrasion with phosphoric acid associated with pumice and hydrochloric acid associated with silicon carbide and evaluate the effect of different polishing techniques on the abrasioned enamel. The hypothesis of this study was that enamel superficial roughness did not differ between the two abrasives tested and the polishing would not cause a reduction in the abrasioned enamel roughness and would not depend on what abrasive was used.

MATERIALS AND METHODS

Sixty bovine incisive teeth were used, which were cleaned and disinfected with thymol (Dinâmica, Piracicaba, São Paulo, Brazil) and submitted to an initial polishing with pumice (SS White LTDA; Rio de Janeiro, RJ, Brazil) and water. After separating the coronary portion by means of a double-face diamond disc (KG Sorensen, Ind. Com. Ltda.; Barueri, SP, Brazil), enamel blocks of 25 mm 2 were obtained using a precision saw (Isomet 1000; Buehler, Illinois, USA) and a high-concentration diamond disc (4" × 012 × ½, Buehler, Illinois, USA). The fragments were included, without covering the top by polystyrene resin, to facilitate handling during planning using silicon carbide emery-cloth of decreasing granulation (1200, 600, and 400) and surface polishing with felts (TOP, RAM, and SUPRA) associated with a diamond paste of decreasing granulation (1 and ¼ µm), greased with a specific oil (Arotec, Cotia; SP, Brazil). The samples were then washed for 15 min in an ultrasonic tub (Marconi, Piracicaba, São Paulo, Brazil) in order to remove any rubbish present on the enamel surface. [15]

The samples were divided into two groups (n=30), and three equidistant markings on the surface of the polystyrene resins surface were procured to drive the initial readings (L1) of roughness, which were made by means of a perfilometer roughness tester (Mitutoyo, Surftest 211; São Paulo, Brazil), so that the readings that followed could always be made in the same locations.

After the initial readings, microabrasion proceedings were initiated, with equal parts of 37% phosphoric acid (Dentsply Ind. e Com. LTDA; Petrópolis, RJ, Brazil) and pumice (SS White LTDA; Rio de Janeiro, RJ, Brazil) being measured and added to group 1 (G1) by means of a dosage spoon (0.1846 g). As for group 2 (G2), a set quantity of the microabrasive Opalustre (Ultradent Products Inc. Utah, USA) was measured with a dosage spoon, and a portion of the agent was applied to each sample. The same application technique was used for both groups, 10 applications per 10 sec of microabrasive product for each sample. After each application of microabrasive product, samples were washed with flow water and were later placed into an ultrasonic tub (Marconi, Piracicaba; SP, Brazil) for 15 min.

After microabrasion, roughness readings were performed (L2), whereupon the groups were subdivided according to the type of polishing material to be used, as follows: Groups 1A and 2A (n=10) - Sof Lex fine and superfine granulation aluminum oxide discs (3M ESPE; St. Paul, MN, USA); Groups 1B and 2B (n=10) - Diamond paste for composite finishing (Diamond Excell/FGM, Produtos odontológicos Ltda.; Joinville, SC, Brazil) associated with felt discs (FGM, Produtos odontológicos Ltda.; Joinville, SC, Brazil); Groups 1C and 2C (n=10) - Silicone tips in the form of a disc (Enhance/Dentsply Ind. e Com. LTDA; Petrópolis, RJ, Brasil). All of the enamel polishing proceedings were performed using a counter-angle, connected to a micro-motor of low rotation (Dabi Atlante; Ribeirão Preto, SP, Brazil) for 30 sec. Next, samples were washed for 15 min in an ultrasonic tub (Marconi, Piracicaba; SP, Brazil) to remove any of the rubbish arising from polishing, whereupon the last roughness reading was performed (L3).

STATISTICS

The data obtained were submitted to statistical analysis. The supposition of sphericity was violated when it was analyzed by means of the Mauchly sphericity test (P < 0.0001), calling for the necessity of the use of PROC MIXED Proceedings for repeated measures of the statistical program SAS. After the data was analyzed, a better structure of co-variance was determined; the PROC MIXED Proceeding was applied, and the Tukey-Kramer test, with a significance level of 5% for multiple comparisons among averages, was performed.

RESULTS

The abrasives tested did not differ significantly in all of the situations tested. The time following microabrasion differed statically from the initial time, and presented greater amounts of roughness, as show in [Table 1].{Table 1}

Regarding the polishing materials used, it was observed that the best-obtained results varied in compliance with the abrasive agent used. For the groups polished with 37% phosphoric acid plus pumice, only polished groups with Sof Lex and Silicone Tips demonstrated a significant reduction in roughness, related to the after-microabrasion time. But with respect to Opalustre, the reduction in roughness was obtained exclusively through diamond paste, related to after-microabrasion time.

DISCUSSION

In this research, the group treated with 37% phosphoric acid paste associated with pumice did not present significant statistical differences in terms of superficial roughness, when compared with the group treated with Opalustre (Ultradent) according to other studies. The characteristics of abrasives, however, are still controversial, principally due to the size of the used particles in relation to the quantity of wastage and roughness that the same may cause.

In their research, Loguercio [16] compared the particle size of different abrasive products, observing more granulation associated with Opalustre's abrasive system (Ultradent) –20-160 µm, followed by Prema Compound's –30-60 µm abrasive system and pumice, with particle sizes varying between 0.8 and 3.0 µm. According to Loguercio, [16] the higher amounts of roughness found in their study were obtained with Opalustre's abrasive system in comparison with Prema Compound's abrasive system, which presents the same abrasive agent in its composition, but with fewer granulations. Further, Papakiritsis [17] reported a greater amount of roughness in treated enamel with pumice, in comparison with a product that contained silica particles as abrasives, with sizes ranging from 0.007 to 0,016 µm (diffusion teeth whitening gel).

Although Opalustre's particle size was larger than that of pumice, which could possibly contribute to more roughness of enamel, this effect was not significant in this study, perhaps due to the acid concentration used in each abrasive system. Opalustre utilizes 6.6% hydrochloric acid in its composition; despite being a strong acid, it was used in low concentration.

This fact could be explained by this research through the erosive power of used acids, as hydrochloric acid demonstrates greater erosive power than phosphoric acid does, thus not resulting in areas of selective conditioning and dysmineralizing equally at the enamel surface. [18] However, as its concentration is reduced (to 6.6%), it is suggested that an equalization occurs in relation to erosive power, which could create a conditioning pattern of the enamel, taking into account a lesser formation of porosity on the enamel surface, making the observed amount of roughness equal to that of phosphoric acid, which is a weak acid in higher concentrations. Thus, the bigger particle size and weakness of the acid used in Opalustre in comparison with the size of the pumice particles associated with 37% phosphoric acid may correlate with the fact that there was no difference between the amount of roughness in both systems.

The microabrasive application on enamel causes the compaction of mineralized tissue inside the organic area of the enamel. This effect occurs through the simultaneous action of abrasion and acid erosion over prisms. [14] Despite the compactness of prisms, the enamel's roughness increased after the microabrasion treatment in relation to the initial abrasion, which is in agreement with the results obtained by Loguercio. [16]

Roughness is intimately connected to brightness and light reflection as well as to the accumulation and retention of dental plaque. Thus, enamel polishing is important, as otherwise the roughness may interfere directly with the esthetics of the teeth and the health of the adjacent tissues. [19] In this study, polishing techniques on abrasioned enamel were used with the assistance of materials usually used for the polishing and restoration of compound resins. Such materials presented excellent results on enamel too. Therefore, aluminum oxide discs, silicone tips, and diamond paste were each used as polishing materials.

It was observed that some of the materials used for polishing reduced the enamel's superficial roughness in such a way that the material type was dependent upon the type of microabrasive used. It is supposed that this result occurs due to the depth of the dysmineralization caused by acids, with the results being consistent with 37% phosphoric acid, which, being present in a greater concentration, creates greater depth of dysmineralization. Thus, when 37% phosphoric acid associated with pumice was used, only silicone tips and aluminum oxide discs obtained relevant results in terms of superficial roughness reduction following microabrasion. Possibly this is due to the granulations of the silicone tip (40 µm) and the aluminum oxide discs (14 µm - fine and 5 µm - extrafine), which are greater than that of diamond paste discs (2-4 µm). The greater granulation of the finishing tip may result in extensive removal of the dysmineralized area by phosphoric acid.

In terms of the group treated with Opalustre (Ultradent) - (Group 2), the results indicated that only the group polished with diamond paste obtained the best results. According to Jefferies, [20] this fact could be due to the small size of diamond granulation present in the diamond paste (2-4 µm). The results obtained in this research still match the results obtained by Scheibe, [21] when comparing superficial roughness of samples of compounds polished by aluminum oxide discs, silicone tips and diamond pastes, obtaining the best results when using such materials. According to Chung, [22] such procedures could reduce the superficial roughness from 26% to 74%, justifying the use of these polishing methods.

According to the results obtained from this research, the avoid hypothesis was partially accepted, as both tested abrasives did not differ in terms of enamel roughness. Nevertheless, the effectiveness of the polishing system varied according to the microabrasive used.

All microabrasive techniques increased the enamel superficial roughness, but no statistical differences came to light among the materials used. The polishing systems caused reduction in the abrasioned enamel superficial roughness of specific groups, in such a way that, the polishing type can be considered as a dependent abrasive.

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