Effects of various finishing devices on resin surfaces

Influence of food-simulating solutions and surface finish on susceptibility to staining of aesthetic restorative materials

OBJECTIVES

To determine the degree of surface staining of resin-based composites (RBCs) and glass-ionomer cements (GICs) after immersion in various stains and food-simulating solutions (FSS).

METHODS

Six tooth-coloured restorative materials were used: a light-cured microfilled RBC (Durafil, Kulzer), a light-cured microglass RBC (Charisma, Kulzer), a polyacid-modified RBC (F2000, 3M/ESPE), a conventional GIC (Fuji IX, GC) and two resin-modified GICs (Fuji II LC, GC; Photac Fil, 3M/ESPE). Disk-shaped specimens were prepared and tested with either a matrix finish or polished using wet silicon carbide papers up to 2000 grit. All specimens were immersed in 37 degrees C distilled water for 1 week, followed by three different FSS (water, 10% ethanol, Crodamol GTCC) and five stains (red wine, coffee, tea, soy sauce and cola) for a further 2 weeks. Three specimens of each material for each stain were tested. Colour coefficients (CIE L* a* b*) were measured by a spectrophotometer after each treatment. The change in colour (DeltaEn) was calculated using the formula: DeltaEn=[(DeltaLn+(Deltaa(n))2+(Deltab(n))2]1/2.

RESULTS

Distilled water caused no perceptible colour change as tested by ANOVA and Tukey's tests. The effect of surface finish on staining was not statistically significant (P>0.05). There was no strong interaction between FSS and stains or between FSS and materials. There was a strong interaction between surface and material, and stain and material (P<0.001).

CONCLUSIONS

All materials were susceptible to staining by all stains especially coffee, red wine and tea; Fuji IX showed the least susceptibility and F2000 the greatest.

Surface roughness of finished composite resins

This study evaluated the results of polishing composite resin by using the following finishing and polishing techniques: Arkansas stone burs; eight-blade tungsten-carbide burs; diamond burs; aluminum-oxide disks; no polishing; and 12- and 30-blade tungsten-carbide burs. The results were compared to ascertain which technique delivers the smoothest surface. The study was done with 120 class V restorations on extracted human teeth distributed in two groups (I and II) of 60 restorations each. Group I teeth samples were filled with microfilled composite resin and Group II with a hybrid composite resin. Readings were made with a profilometer to evaluate the final polishing. The conclusions from the results of the study were that microfilled composite resins provided a better finish when treated with aluminum-oxide disks. These results were statistically significant (p < 0.001). When hybrid composites were used the control group recorded the lowest values.

Comparison of wet and dry finishing of resin composites with aluminum oxide discs

Samples of four composites (Herculite, Visio-Dispers, Silux, and Prisma-Fil) were finished with aluminum-oxide discs either wet or dry so that the effects of these two finishing procedures could be compared. The samples were evaluated for surface smoothness, color stability, and surface hardness. Surface smoothness was determined immediately after a sample was finished with a profilometer. Knoop hardness values were determined for each sample immediately after being finished and once a week for five weeks. Color stability was evaluated with a tristimulus colorimeter by the color of each sample being finished and once a week for five weeks. When surface smoothness was compared between the wet- and dry-finished samples, there was no significant difference between Prisma-Fil, Silux, or Herculite; however, the wet-finished Visio-Dispers was significantly rougher than the dry-finished. When surface hardness was compared, there was no significant difference in hardness values between the wet and dry samples when compared over time. When changes in color were evaluated, only Visio-Dispers had no significant change in color for both the wet- and dry-finished samples over the five-week evaluation period. Dry finishing of only one composite (Silux) produced a significant change in color. Dry finishing of composites was superior or equal to wet finishing in all tests except for the color change in Silux.

In vitro color change of composite-based resins

The adsorption of staining materials to resin restoratives was considered to be influenced by the physico-chemical properties of the resin-based monomers. To study the effects of the surface characteristics of resins on staining, we prepared five visible-light-cured experimental resins without fillers. Staining of these resins was colorimetrically measured. The staining solutions used were the Oil Orange and the Food Red 3 solutions. With the Oil Orange solution, the materials with higher hydrophobicity showed higher staining. With the Food Red 3 solution, the materials with higher water sorption showed higher staining.

The nature and effects of composite finishing pastes

Specimens of composite resins, contoured and finished with a series of microfine diamonds, were finished with a selection of commercially available composite finishing pastes. The resulting surfaces were examined using scanning electron microscopy (SEM) and surface profilometry. Samples of the pastes were investigated using SEM and energy dispersive X-ray spectroscopy. All the paste systems employed an abrasive of similar composition and particle size. The selection of finishing pastes produced marked improvements of the surfaces of the composite resins. The small differences measured between the performances of the four finishing pastes included in this study could not be corroborated by SEM evaluation. Therefore, within the limitations of this study, there was little evidence to suggest that any one paste system was superior to the others. The results of this study indicate that commercially available composite resin finishing pastes of the type investigated may be used to improve the surface of all types of contemporary composite resins and may be of particular value in finishing the concave surfaces of restorations of composite resins following contouring and finishing with microfine diamond burs.

The polishability of posterior composites

The polishability of six brands of posterior composites was evaluated by means of a stylus profile instrumentation and scanning electron microscopy and was compared with that of an anterior microfilled composite. A sedigraphic study was performed to estimate the size and distribution of their inorganic particles. The extent of the filler loading as well as the hardness values were also assessed to determine any relevant characteristics. Some of the findings indicated that posterior composites with large particles produced significantly higher surface roughness than those with small fiber particles. A direct correlation was also found between the hardness value and surface roughness value, indicating that a composite with higher hardness value yielded a higher roughness value.

The surface finish of the new microfill restorative materials. A scanning electron microscope study

Surface smoothness is an important requirement for restorative materials. Recently, restorative materials claimed to be inherently smooth in surface characteristics have been developed. Matrix-formed and finished surfaces of five new microfill restorative materials were compared with two composite resins, an acrylic resin and a silicate cement by means of scanning electron microscopy. The results of this investigation indicated that the matrix-formed surfaces of all the restorative materials studied were not altogether perfect. Polishing using sandpaper and cuttlefish discs produced a very smooth surface finish in the new microfill restorative materials, Estic microfill, Estilux microfill, Isopast, Isolux and Silar which was comparable to that of the acrylic resin, Sevriton. The composite resins, Adaptic and Estilux exhibited the worst surface finish and the silicate cement, Bio-trey was intermediate. Finishing, using other finer polishing devices on four of the materials produced a further improvement in the surface finish.

The porosity and roughness of four direct filling resins

Four direct filling resins were examined in order to compare the roughness and porosity of different materials, mixed by different methods. From each material six specimens were prepared. Each specimen was formed against a Mylar sheet and the Mylar-formed surface was examined. Subsequently it was trimmed and polished and re-examined. Each specimen was examined with a microscope using incident light and employing an automatic point-counting attachment in order to assess the percentage surface (apparent) porosity. Each specimen was also examined with a stylus-type profile meter. Rt (total roughness height) was recorded for all specimens and Ra (roughness average) was recorded for all polished specimens. The findings support the conclusion that a capsulated resin without an inorganic filler yields a better surface than other resins.

Occlusion for successful class IV acid-etch restorations

Properly placed acid-etch Class IV restorations may be dislodged due to occlusal interferences. When restoring an anterior tooth, the dentist should check the three regions of possible incisal prematurities: centric incisal contact, protrusive incisal contact, and midprotrusive incisal contact. By correcting potential problems in these regions before tooth restoration, the dentist helps to ensure longer lasting retention for the restoration.

The effect of finishing composite resin surfaces at different times

This study was designed to compare the surface smoothness of two composite resins finished at different time intervals. The results indicate that the surfaces of the composite resins are unquestionably smoother when polymerized against a matrix. However, when finishing procedures are needed, none of the time intervals tested in this study produced a smoother surface. This investigation demonstrates that smoothness of composite resin after finishing is not a function of the time at which it is finished.

Effect of finishing procedures on surface textures of some resin restoratives. A comparison between new and old types of composite resins

Evaluation were made of the effect of different finishing procedures on the surface textures of a conventional composite material, two newly introduced microfiller composite resins, a visible light polymerized resin, and a glass ionomer cement. The two micro-filler composite materials appeared to be superior in finishability compared with those materials loaded with larger filler particles. The use of fine grit devices particularly resulted in smooth surfaces. This is in contrast to the other materials which always showed rough surface textures with protruding filler particles. The use of a polishing paste improved the surface finish of the micro-filler materials in contrast to the materials with larger filler particles.

Multiple-abutment fixed partial dentures in maxillofacial prosthetics

Ten patients were presented to illustrate multiple-abutment fixed partial dentures used in combination with auxiliary prosthetic attachments of a fixed or removable design to solve diverse problems encountered in the rehabilitation of congenital and acquired orofacial defects. While such fixed prostheses have high initial costs, their effectiveness and long-term cost-benefits suggest that, where appropriate, they represent optimum therapy that will prove most economical over the long term.

A study of the contour and external surface of class V composite resin fillings

Twenty-five Class V Composite-resin, Adaptic fillings were prepared on extracted human teeth under five different matrices. White stones and flame diamonds were used as polishing devices. The smoothest surface was obtained with celluloid strip and the most acceptable contour obtained with preformed matrix.

Surface finish of dental composite restorative materials

Five composite filling materials were finished using six finishing procedures currently in clinical use. The average roughness produced by each procedure was measured by means of a Surfanalyzer with four replications for each procedure on each of the five materials. Statistical analysis indicated that finishing with silicon carbide disks produced the smoothest surfaces. Acceptable surfaces were obtained with stones or with burs. Use of an alumina paste after a green stone-white Arkansas sequence did not produce a significant improvement. Two processes of filler particle abrasion were distinguished by means of electron microscopy: wear and shear. Fracture striations indicated particle shear. The roughest surfaces were produced by the use of a diamond instrument which is contraindicated. Acceptable finishing procedures for the composite materials tested include silicon carbide disks for accessible areas or 12 fluted finishing burs for more inaccessible areas.

The strength of multilayer and repaired composite resin

Composite resin surfaces that formed against a plastic matrix or that polymerized while exposed to air were excellent substrates for the adhesion of new resin. Samples formed by the addition of composite resin to a cut surface had a tensile strength of one half of the cohesive strength of the resin. Coating the cut surface with a thin layer of unfilled resin enhanced bonding of the second composite resin layer. The use of a thin layer of unfilled catalyst resin as a bonding agent caused the most rapid development of strength and the greatest strength in samples tested after 7 days.

An evaluation of commercial pastes for finishing composite resin surfaces

A study was conducted to determine the effectiveness of several commercial pastes in polishing the surfaces of composite resin material. Five samples of Concise composite resin contained within Plexiglas block holders were prepared using Mylar matrices. One block was disked only; three blocks were disked and polished, each with a different paste. The remaining block was the control. The surface roughness of all samples was measured with a stylus profile instrument. Five extracted teeth were prepared in the same manner with Concise composite resin and Mylar strip matrix. In each tooth, the surface was finished by disking only or by disking followed by polishing with one of three pastes. The fifth tooth was the control. The samples were examined by use of a scanning electron microscope. Quantitative evaluation of over-all computer data indicated that the smoothest surface was found immediately ater removal of the Mylar matrix and that pastes leave a rougher surface than is left with a disc.

Bonding metal brackets with a self-polymerizing sealant-composite: a 12-month assessment

Data spanning 15 months and about 1,500 bands have been presented describing an effective procedure for bonding metal brackets to enamel by the acid-etch method. A sealant-composite combination for metal brackets, not previously reported, has been described. Data have also been presented showing that, for the method and material used, it did not seem to matter clinically if a 37 per cent acid were used or if, instead a 50 per cent orthophosphoric acid in a liquid or thixotropic form, applied for 2 to 2 1/2 minutes, and drying agent were used. A comparison with the Nuva system was made and a modification was described for a useful combination technique, namely, Enamel Bond-Nuva-Tach, which takes advantage of certain attributes of each.