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At least 1,207 records · Page 67Linked to original sources
PubMed1999

Wear of composite resin inlays and antagonistic enamel.

PURPOSE: To evaluate the wear of composite resin inlays and antagonistic enamel wear when they opposed each other. MATERIALS AND METHODS: Cylindrical-shaped composite disk specimens were fabricated with three composite resin inlay materials and a heat-treated direct composite resin (control). The lingual cusps of extracted human maxillary premolars were placed perpendicular to flatten composite resin inlay specimens. Two body localized wear test was carried out using six specimens per material. The surface area of worn enamel and composite specimens was measured by a computerized analysis system. RESULTS: There were statistical differences between inlay materials and the control with respect to enamel wear, although no differences existed between the inlay materials tested. Worn enamel analysis by SEM indicated that large size quartz filler particles created the coarsest surface. The results suggest that the composite resin inlay materials tested are better than the quartz-containing composite resin in terms of antagonistic enamel wear.

Analysis of Variance↗
PubMed2000

Resin-based composites and compomers in primary molars.

Resin-based composite resins and polyacid-modified resin-based composites (compomers) have become popular for the restoration of primary anterior and posterior teeth. In some European countries, resin-based composites or glass-ionomers are the materials of choice for primary teeth because of the controversy over dental amalgam and its alleged adverse health effects resulting from the release of mercury, although a clear correlation between amalgam restorations and health has not been determined. Another reason for the worldwide increased use of resin-based composites and glass-ionomers in pediatric dentistry could be attributed to the growing demand from parents to provide esthetic restorations to their children. More conservative preparations can be performed maintaining more tooth structure because of the adhesive properties of the composites and compomers. The most conservative treatment planning and meticulous care in the placement of the resin-based composites and compomers would produce long-term satisfactory results. These restorations should be placed in patients with low-to-moderate caries risk, and after placement the restorations should be monitored carefully to avoid complications mainly produced by recurrent caries and wear.

Adhesives↗
PubMedDate not supplied

Resistance to condensation of 'condensable' resin composites as evaluated by a mechanical test.

This study compared the resistance-to-condensation forces of recently introduced condensable resin composites to that of amalgams and conventional resin composites. Using the flat platens of a servohydraulic testing machine, cylindrical specimens of each material 2.8 mm in diameter and 5.5 mm in length were compressed diametrally over two seconds to a thickness of 0.75 mm. Peak forces generated during compression were recorded. This method ranked the various classes of restorative material for resistance to condensation in the same order as most clinicians subjectively reported, with the highest forces observed with admixed dental amalgams, followed in order by spherical amalgams, condensable resin composites and conventional resin composites. Although peak forces observed with the condensable resin composites were generally higher than those observed with conventional resin composites, these were significantly lower than the peak forces observed with amalgams.

Analysis of Variance↗
PubMed2001

Control of brittleness in butyl-methylmethacrylate resin embedding mixtures to facilitate their use in immunofluorescence microscopy.

Butyl-methylmethacrylate resin mixtures were tested for brittleness-inducing factors in polymerised resin using a rapid quantitative scoring technique. The major source of brittleness was identified as the reducing agent dithiothreitol, which is commonly included in resin mixtures at 10 mM, to protect against tissue oxidation. Lowering the dithiothreitol content to 5 mM substantially reduced brittleness. Changing the 4:1 ratio of butyl- to methylmethacrylate to 9:1 or 3:2, and reducing the concentration of the catalyst, benzoin ethyl ether, to 0.25% also reduced dithiothreitol-induced brittleness. Polymerisation at temperatures close to 0 degrees C increased dithiothreitol-induced brittleness, but this was controlled in the 4:1 and 9:1 resin mixtures by lowering the catalyst concentration from 0.5 to 0.25%. Degassing the resin mixture with nitrogen gas prior to polymerisation did not reduce brittleness. Immunolabelled onion roots which were embedded using the 3:2 resin mixture ratio, 5 mM dithiothreitol and the 0.25% catalyst concentration, showed excellent preservation of cortical microtubule arrays.

Dithiothreitol↗
PubMed2001

Marginal adaptation of amalgam and resin composite restorations in Class II conservative preparations.

OBJECTIVE: The purpose of this study was to compare and contrast the performance, in terms of marginal adaptation, of a non-gamma-2 amalgam alloy with a compact-filled light-cured composite in the restoration of Class II preparations of conservative design. METHOD AND MATERIALS: Fifty recently extracted teeth were selected for the study. The teeth were restored with either a non-gamma-2 amalgam alloy, Dispersalloy, or a compact-filled resin composite, Z100, using standard techniques. The marginal adaptation of the restorative materials to the proximal surface outline form of each preparation was assessed at magnification x30. RESULTS: Highly significant differences were demonstrated in the mean percentages of perfect margins in all 3 segments of the proximal boxes of the restorations with the resin composite performing significantly better than the amalgam. The percentages of marginal fissuring were significantly higher in the amalgam restorations, except at the cervical margin, where the incidence of fissuring was almost the same for the amalgam and resin composite restorations. The resin composite restorations had significantly fewer underfilled margins than the amalgam restorations. CONCLUSION: In the conservative Class II preparations, the amalgam restorations were of poor quality with respect to marginal adaptation, compared with the resin composite restorations. It is suggested that the use of amalgam as a control in a clinical evaluation of resin composite restorations in conservative preparations cannot be justified, because it is apparently not possible to compare restorations of equivalent initial quality.

Bicuspid↗
PubMedDate not supplied

Remineralization across the resin-dentin interface: in vivo evaluation with nanoindentation measurements, EDS, and SEM.

OBJECTIVE: The purpose of this study was to evaluate the in vivo remineralization of the possible non-resin infiltrated hybridoid layer between the hybrid layer and the subjacent dentin substrate using nanoindentation, energy dispersive x-ray spectroscopy microanalyses (EDS), and scanning electron microscopy (SEM) technologies. METHOD AND MATERIALS: Twenty Class V cavities were placed in healthy adult monkey teeth. Each cavity was total etched with 37% phosphoric acid for 60 seconds, rinsed, and air dispersed, and SA-Primer was applied to the collagen layer. Cavities were divided into two groups: In group 1, Protect Liner (low-viscosity resin) and Clearfil AP-X (resin composite) were placed per manufacturer's directions, and no bonding agent was placed on the acid-etched interface. In group 2, Clearfil Photobond (bonding agent) was applied, and Protect Liner and Clearfil AP-X were placed as in group 1. Teeth were observed at 7 days (control) and 6 months by nanoindentation, EDS, and SEM. RESULTS: Six-month data showed an increased nanohardness in areas 5 pm adjacent to the demineralized or partially demineralized dentin interface. Following treatment with a conventional adhesive system on the acid-etched interface (group 2), there were increased nanohardness and calcium EDS measurements in the substrate just below the resin-dentin impregnated layer. CONCLUSION: Our 6-month in vivo nanoindentation and EDS data demonstrate that the non-resin infiltrated zone becomes remineralized following adhesive resin treatment.

Acid Etching, Dental↗
PubMed1999

Durability of resin-dentin bonds.

PURPOSE: The purpose of this study was to determine if the durability of resin-dentin bonds could be evaluated more quickly if the bond specimen was divided into 1 x 1 x 8 mm beams incubated at 37 degrees C for a 90-day period. MATERIALS AND METHODS: Extracted human third molars were prepared for bonding by removing the occlusal surface near the dento-enamel junction (superficial dentin group) or near the pulp (deep dentin group). The teeth were bonded either with MacBond, One Step or Clearfil Liner Bond 2, and then builtup to form a flat resin composite crown. After 24 hours in water, each buildup was vertically divided into slabs 1 mm thick, the top half of which was resin, with the bottom half as dentin. Each slab was then vertically sectioned at 1-mm increments to create 1 x 1 x 8-mm beams of resin-bonded dentin. They were incubated for 1 day or 90 days at 37 degrees C, followed by measurement of the tensile bond strengths. The results were analyzed by the Least-Squares Means method at the 95% confidence level. RESULTS: MacBond gave the highest (p < 0.05) 1-day bond strengths to superficial dentin, but significantly lower bond strengths were measured in deep dentin. There were no significant differences in the bond strengths of either One Step or Clearfil Liner Bond 2 to superficial vs deep dentin at 1 day, but at 90 days their bond strengths to deep dentin had fallen significantly (p < 0.05). Prepolymerized cylinders of resin composite bonded together with One Step showed little variation in bond strength over the 90-day experiment. SEM examination of the failed bonds showed increased porosity in intertubular dentin over time. CONCLUSION: The results indicate that division of large specimens into many small beams accelerated the deterioration of bond strength in deep dentin in all three bonding systems and in both superficial and deep dentin in the MacBond treated specimens. This method seems promising for studying the durability of resin-dentin bonds.

Alkanes↗
PubMedDate not supplied

Evaluation of the clastogenic activity of some resins used in the prosthodontic field.

BACKGROUND: Dental materials, in particular resins used in prosthetic, orthodontic, conservative and gnathological dentistry, are frequently in long-term contact with the tissues of the mouth, and the chronic exposure to these products of a significant proportion of the population means that the release of genotoxic substances by dental resins must be evaluated. METHODS: For this purpose, ten methyl metacrylate-based resins, both cold- and hot-polymerising and all of frequent use in clinical practice, were prepared following the indications in Standard UNI 9582-2 now included in Standard ISO 10993. Genotoxicity was evaluated through the Tradescantia/micronuclei test. RESULTS: By using the Tradescantia/micronuclei test, which detects aberrant chromosomes by detecting micronuclei in flower tetrads, nine resins were found not to the positive; one resin caused a significant increase in the frequency of micronuclei compared to negative controls. CONCLUSIONS: The results of the Tradescantia/micronuclei test, together with the results of tests cytotoxicity and the Ames and Allium cepa tests performed in previous research, indicate a need for further analyses of these resins for dental use, through other in vivo and in vitro tests, in order to achieve certainty over the risk connected with their use in human populations.

Acrylic Resins↗
PubMed2001

The effect of powder/liquid mixing ratio on the stiffness and impact strength of autopolymerising dental acrylic resins.

The stiffness of representative cured autopolymerising dental acrylic resins was determined by calculation of a secant modulus from measurements in tension of load and extension, and related to the powder/liquid mixing ratio. The impact strengths of autopolymerising, heat-cure and commercial resins were compared. It was found that while the stiffness of autopolymerising resins was unaffected by variations in powder/liquid mixing ratio, extension to failure was greater with lower powder/liquid ratios. The impact strength of autopolymerising resins was found to be greater than that of heat-cure resins, and a tentative explanation is offered. These findings may help to explain the pattern of failure of acrylic resin denture bases.

Acrylic Resins↗
PubMedDate not supplied

[Polymerization exothermal reaction of dental prosthetic resin for temporary crowns. A comparative evaluation].

BACKGROUND: The aim of the present study is to evaluate the risk of a possible thermal stress of the pulpal tissue during the fabrication of a temporary crown when using the direct technique. METHODS: For this study, 7 different brands of acrylic resin including Acrylic type and Bis-Gma type have been tested. At this purpose one series of in vitro experimental trials were performed. The trials have evaluated the temperature increase inside the pulp chamber of an extracted tooth during the fabrication of a provisional crown. The temperatures reached by the resins tested were measured using a digital thermometer connected with a thermal probe. RESULTS: The temperatures measured during the experimental trials show a different ability by the 7 tested resins to produce heat. Indeed, while the polymethylmethacrylate resins show higher increments rate of temperature, the Bis-Gma resins produce less dramatic increase along with lower temperatures peaks. CONCLUSIONS: Testing the 7 different resins has proved that there is an actual risk to cause lesions to the pulpal tissue during the placement of a provisional crown when using the direct technique. The materials which show a reduced exothermal reaction are: IsoTemp and Protemp II.

Crowns↗
PubMedDate not supplied

Probability of failure of highly filled indirect resin-veneered implant-supported restorations: an in vitro study.

PURPOSE: The study compared the probability of failure of three highly filled resin-veneered restorations to that of conventional metal-ceramic restorations when used as implant-supported prostheses. The effect of the location of load application on the fracture resistance of the restorations was also studied. MATERIALS AND METHODS: Twenty samples each of the three resins, Artglass, Targis, and Estenia, were applied on type IV gold frameworks. Twenty metal-ceramic restorations of equal dimensions (VMK 95 and Degudent Universal) were used as controls. Compressive load was applied vertically at 1 mm (n = 10) and 2 mm (n = 10) from the periphery of the occlusal table until the restorations failed. Weibull analysis was applied to the data. RESULTS: There was no significant difference in the probability of failure among the metal-ceramic restorations and three resin-veneered restoration systems. Loading the resin-veneered restorations at the 1-mm location significantly increased their probability of failure when compared to the 2-mm loading location. The loading location did not significantly change the probability of failure of the metal-ceramic restorations. CONCLUSION: The probability of failure of resin-veneered restorations tested was not significantly different from that of the metal-ceramic restoration under two compressive loading conditions. Eccentric loading of resin-veneered restorations should be minimized in light of the higher probability of failure associated with such a loading condition.

Analysis of Variance↗
PubMedDate not supplied

Effect of ceramic surface treatment on tensile bond strength to a resin cement.

PURPOSE: The objective of this study was to test the following hypotheses: (1) hydrofluoric acid (HF)-treated ceramic surfaces produce the highest tensile bond strength to resin cements, independent of the ceramic microstructure and composition; and (2) the tensile bond strength test is appropriate for analysis of interfacial adhesion for ceramic-bonded-to-resin systems. MATERIALS AND METHODS: Ceramic specimens were polished with 1-micron alumina abrasive and divided into four groups of 10 specimens for each of seven ceramic types. One of the following surface treatments was applied: (1) 10% ammonium bifluoride (ABF) for 1 minute; (2) 9.6% HF for 2 minutes; (3) 4% acidulated phosphate fluoride (APF) for 2 minutes; and (4) a silane coupling agent. The surface-treated areas were coated with an adhesive resin and bonded to a resin cement. Specimens were loaded to failure in tension using a testing machine. Tensile bond strength data were statistically analyzed, and fracture surfaces were examined to determine the mode of failure. RESULTS: Silane-treated surfaces showed statistically higher mean tensile bond strength values than surfaces treated with any etchant (HF, ABF, APF). HF produced statistically higher mean tensile bond strengths than ABF and APF. All failures occurred in the adhesion zone. CONCLUSION: The tensile bond strength test is adequate for analysis of the adhesive zone of resin-ceramic systems. The chemical adhesion produced by silane promoted higher mean bond strength values than the micromechanical retention produced by any etchant for the resin-ceramic systems used in this study.

Acid Etching, Dental↗
PubMed2002

Laboratory strength of glass ionomer cement, compomers, and resin composites.

PURPOSE: The study evaluates the compressive, flexural, and diametral tensile strengths of 8 core build-up materials from different material classes (highly viscous glass ionomer cement, autocured resin composite, and compomers). MATERIALS AND METHODS: All materials were manipulated according to the manufacturers' recommendations for use as core materials. At a temperature of 23.0 +/- 1.0 degrees C the properties of compressive, diametral tensile and flexural strength were determined using a universal testing machine at 15 minutes, 1 hour, and 24 hours after material preparation. Using one-way analysis of variance (ANOVA), multiple mean value comparisons were performed to determine significant differences (p< or =.05) between the core restoration materials. RESULTS: The values for compressive strength varied from 40.3 +/- 5.2 MPa (compomer) to 237.4 +/- 37.3 MPa (autocured resin composite) for the 3 measurement times. At 15 minutes, 1 hour, and 24 hours after first mixing, the ANOVA showed significant differences (p < or =.05) between the resin composite Core Paste and all of the other materials. Diametral tensile strengths ranged from 5.5 +/- 1.1 MPa for glass ionomer cement to 39.1 +/- 2.9 MPa for composite core material. Three-point flexural strength showed values ranging from 12.1 +/- 2.5 MPa for glass ionomer cement to 92.1 +/- 9.7 MPa for compomer between the 3 measurement times. CONCLUSIONS: Setting time influences the mechanical properties of the materials tested in this study. Autopolymerizing resin composite Core Paste demonstrated greater compressive and flexural strengths at the 3 measurement times than the other materials tested. Reinforced composites, in comparison to the autocured resin composites, yielded no improvement in tensile strength. Flexural and tensile strengths of the glass ionomer cement were lower than those of autocured resin composites and compomers.

Analysis of Variance↗
PubMedDate not supplied

Effect of thickness of flowable resins on marginal leakage in class II composite restorations.

Despite limited scientific evaluation, there is an increased use of low elastic modulus flowable resin composite (FRC) as a stress-relieving gingival increment in Class II restorations. This study compared marginal leakage in preparations with gingival margins in enamel or dentin/cementum (sub-CEJ and supra-CEJ) after FRC was used as a gingival increment to hybrid resin composite used alone. In addition, the extent of leakage around restorations with or without the use of FRC gingival increments when light curing the resin composites from occlusal direction only or buccal, lingual and occlusal directions was compared. Sixty extracted human molars were prepared with two identical Class II (MO and OD) preparations (30 were 1 mm sub-CEJ and 30 were 1 mm supra-CEJ) and randomly assigned to six groups. After etching, dentin-bonding agent was applied to all prepared tooth surfaces according to the manufacturer's specifications. One of three different thicknesses of FRC (0.5 mm, 1 mm or 2 mm) was placed on the gingival floor, cured and a hybrid resin composite was placed occlusally to complete the restoration. The control preparation on each tooth was restored in the same manner, except that a hybrid resin composite was used for both the gingival and occlusal increments. The restored teeth were thermocycled (300 cycles), then immersed in 50% silver nitrate prior to the hemi-section and measured for leakage under a light microscope. The data were evaluated using paired measures analysis of variance (ANOVA). Most of the occlusal margins showed no leakage, while almost every gingival margin demonstrated some silver nitrate penetration regardless of whether it was located sub or supra-CEJ, although significantly less leakage was found in restorations with supra-CEJ margins (p=0.0001). Among supra-CEJ restorations, there was a pronounced reduction in leakage as FRC thickness increased (p=0.0005). In the teeth restored with the gingival-margin located supra-CEJ, the 2 mm thickness FRC gingival increment showed significantly less leakage (p<0.01) compared with the 0.5 mm thickness of FRC gingival increment. The direction of the curing light did not affect the extent of leakage (p>0.05). The use of FRC material as a gingival increment sub-CEJ in posterior hybrid resin restorations produced no significant difference in leakage (p>0.05). The results of this study indicated that restorations located supra-CEJ (with gingival margins in enamel) with 2 mm thick FRC gingival increments demonstrated significantly less leakage than did those with 0.5 mm FRC. When the margin of the restoration was located sub-CEJ (in dentin/cementum), neither the thickness nor the presence of FRC as a gingival increment significantly influenced the marginal leakage.

Acid Etching, Dental↗
PubMed2002

Efficacy of self-etching primers in the adhesion of 4-META/MMA-TBB resin cement to enamel.

PURPOSE: The effect of self-etching primer on the adhesion of tri-n-butylborane (TBB)-initiated resin cement to enamel has not been determined. This study evaluated the effectiveness of the self-etching primer by measuring the tensile bond strength between enamel and TBB-initiated methyl methacrylate (MMA) resin containing 4-methacryloxyethyl trimellitate anhydride (4-META). MATERIALS AND METHODS: The self-etching primers were an aqueous mixture of 30 wt% methacryloxyethyl phosphate, 35 wt% 2-hydroxyethyl methacrylate, and ferric chloride. The concentration of ferric chloride was varied from 0 to 7 wt%. The bovine enamel surface was treated with self-etching primer for 30 s. After drying, a stainless steel rod was bonded to the enamel using TBB-initiated 4-META/MMA resin cement. The tensile bond strengths were measured after 1 day of immersion in 37 degrees C water and after thermal cycles between 4 degrees C and 60 degrees C. The resin-enamel interface was observed under field-emission scanning electron microscopy (FE-SEM). RESULTS: The self-etching primer containing 5 wt% ferric chloride (Phosmer-5Fe) yielded the highest mean bond strength and significantly higher bond strengths than phosphoric acid etching after 1 day of immersion. After 5000 thermal cycles, the bond strength with Phosmer-5Fe was still significantly higher than that with phosphoric acid etching. FE-SEM images revealed tight bonding between the resin and enamel in the specimens of Phosmer-5Fe primer treatment. CONCLUSION: The self-etching primer treatment may be an alternative to phosphoric acid etching for the adhesion of TBB-initiated 4-META/MMA resin cement to enamel.

Acid Etching, Dental↗
PubMedDate not supplied

Comparison of impact strength of acrylic resin reinforced with kevlar and polyethylene fibres.

The present study was done to evaluate the impact strengths of heat-activated acrylic resins reinforced with Kevlar fibres, polyethylene fibres and unreinforced heat activated acrylic resin. Each of three groups had 25 specimens. Brass rods of uniform length of 40 mm and diameter of 8 mm were used to prepare the moulds. A combination of long fibres (40 mm length) and short fibres (6 mm length) were used. The total amount of fibres incorporated was limited to 2% by weight of the resin matrix. Short and long fibres of equal weight were incorporated. The short fibres were mixed with polymer and monomer and packed into the mould, while, the long axis of the specimen, perpendicular to the applied force. The specimens were then processed. Impact strength testing was done on Hounsfield's impact testing machine. Kevlar fibre reinforced heat activated acrylic resin specimens recorded higher mean impact strength of 0.8464 Joules, while polyethylene fibres reinforced heat activated acrylic resin recorded mean impact strength of 0.7596 joules. The unreinforced heat activated acrylic resin recorded mean impact strength of 0.3440 Joules.

Acrylic Resins↗
PubMed2000

[Effects of pulsed Nd:YAG laser irradiation on shear bond strength of composite resin bonded to porcelain].

OBJECTIVE: To evaluate the shear bond strength of composite resin bonded to pretreated porcelain surfaces by use of a pulsed Nd:YAG laser irradiation and by use of 8% hydrofluoric etching. METHODS: Surfaces of porcelain were roughened with coarse diamonds until the opaque body porcelains were exposed. The samples were divided into four groups. Samples of the first group were etched with 8% hydrofluoric acid for 3 min by following the manufacter's instructions. Samples of the 2nd, 3rd and 4th groups were separately irradiated by a pulsed Nd:YAG laser of three energy parameters of 15 Hz, 40 mJ; 0.6 W; 15 Hz, 60 mJ, 0.9 W and 15 Hz, 80 mJ, 1.2 W different respectively, each specimen was irradiated for 1 min. Then, silane coupling agent was equally placed on the treated surfaces for 3 min, the activator was used on each surface. The adhesive was applied and light-cured. The composite resin material was finally bonded to the treated porcelain surface, forming a 3 mm x 3 mm x 2 mm resin mass. Samples were then tested for shear bond strength between the treated porcelain and composite resin by using a SWD-10 electric universal testing machine with a crosshead speed of 1 mm/min until fracture. At the end of testing, the data was evaluated by using a two-way analysis of variance (ANOVA) comparing the shear bond strength. On the other hand, characteristic morphology of laser irradiated surfaces of porcelain was prepared and observed by a scanning electron microscopy. RESULTS: The shear bond strength of laser groups of 0.6 W, 0.9 W, 1.2 W and etching group was respectively 8.61, 14.07, 11.22 and 13.47 MPa. There was no significantly difference among groups of laser 0.9 W, 1.2 W and the etching group. This suggested that irradiated on surfaces of porcelain by Nd:YAG laser at the above laser energy could attain the same effectiveness as hydrofluoric acid etching. But the shear bond strength of laser 0.6 W group was significantly lower than the etching group. It suggested that shear bond strength would obviously decrease when laser energy was 0.6 W or lower than this parameter, and had no use in treatment on porcelain surfaces comparing to acid etching. SEM showed that porcelain surfaces irradiated by Nd:YAG laser exhibited rough, umbilicate, lava crater-like structure. This structure helped to produce mechanical retention between resin composite and porcelain. CONCLUSION: The pulsed Nd:YAG laser could replace etching method to pretreat the fracture porcelain surfaces for bonding with composite resin at appropriate energy parameters.

Composite Resins↗
PubMed2002

Cleaning and polishing efficacy of abrasive-bristle brushes and a prophylaxis paste on resin composite material in vitro.

OBJECTIVE: This study evaluated the cleaning and polishing effect of a prophylaxis paste (Cleanic), two differently shaped abrasive-bristle brushes (Occlubrush normal cup and Occlubrush minipoint), and a nylon-bristle brush (Prophy brush) on a fine (Tetric Ceram) and a coarse hybrid resin composite (Tetric Condense) under standardized conditions. METHOD AND MATERIALS: A total of 48 round specimens with a diameter of 17.2 mm (232.32 mm2) of a fine and a coarse hybrid resin composite were readied and fixed on scanning electron microscopic mounts. After a standardized polishing procedure, the mean surface roughness values were evaluated using five horizontal and five vertical measurements over an area of 1 x 3 mm. The gloss of each specimen was assessed with a spectrophotometer. Both hybrid resin composite groups were treated with one of the following instruments: a nylon-bristle brush (n = 8), a normal-cup abrasive-bristle brush, or a minipoint abrasive-bristle brush. The medium used was either water (control) or a prophylaxis paste. Surface roughness and gloss were measured after instrumentation times of 15, 30, 60, 90, and 120 seconds. For the evaluation of cleaning ability, another 48 total round specimens of fine and coarse hybrid resin composite were covered with a thin layer of black dispersion color and air dried for 24 hours. Specimens were treated with a nylon-bristle brush or an abrasive-bristle brush in combination with water or prophylaxis paste for 15, 30, 60, 90, and 120 seconds. At the beginning and after every treatment interval, the specimens were scanned, the images were digitized, and the percentage of cleaned surface was measured planimetrically. RESULTS: The abrasive-bristle brush, used in combination with water, produced the best outcomes for cleaning ability, surface roughness, and gloss on resin composite restorations. CONCLUSION: There is no positive cumulative effect when an abrasive-bristle brush, with its cleaning and polishing effect, is used in conjunction with a prophylaxis paste. Abrasive-bristle brushes used with plain water are highly suitable for cleaning and polishing resin composite surfaces.

Composite Resins↗