Dental bleaching with a 10% hydrogen peroxide product: a six-month clinical observation.

CONTEXT: The possibility of bleaching vital teeth with peroxide-based products considerably revolutionized esthetic dentistry. AIM: The aim of this clinical study was to evaluate tooth color change and dental sensitivity after exposure to preloaded film containing a 10% hydrogen peroxide whitening system (Opalescence Trθswhite Supreme). MATERIALS AND METHODS: A total of 13 volunteers, aged 18 to 25 years, participated in this study. The patients used the whitening system once a day for 60 minutes during the 8-day study. For maxillary incisors and canines, the color change was visually evaluated with the Vita color scale before, immediately, and six months after the treatment. Tooth sensitivity was evaluated during the daily gel applications. All whitening applications were done in office and under the supervision of a dental professional. STATISTICAL ANALYSIS USED: The results were analyzed using the Friedman Test (nonparametric repeated measures ANOVA) at a level of 5%, and Dunn's Multiple Comparison Test at the level of 5%. RESULTS: It was verified that the original mean color values observed at the baseline analysis differed significantly from those observed immediately after bleaching, as well as from those seen in the analysis at six months ( P = 0.001). There was no significant difference between the mean color values observed in the immediate time and in the analysis at six months ( P = 0.474). No tooth sensitivity was observed in any patients. CONCLUSION: It was concluded that the bleaching technique using the 10% hydrogen peroxide system was effective in a short period of time without tooth sensitivity during applications.

Smile restoration through use of enamel microabrasion associated with tooth bleaching.

Enamel microabrasion can eliminate enamel irregularities and discoloration defects, improving the appearance of teeth. This article presents the latest treatment protocol of enamel microabrasion to remove stains on the enamel surface. It has been verified that teeth submitted to microabrasion acquire a yellowish color because of the thinness of the remaining enamel, revealing the color of dentinal tissue to a greater degree. In these clinical conditions, correction of the color pattern of these teeth can be obtained with a considerable margin of clinical success using products containing carbamide peroxide in custom trays. Thus, patients can benefit from combined enamel microabrasion/tooth bleaching therapy, which yields attractive cosmetic results. Esthetics plays an important role in contemporary dentistry, especially because the media emphasizes beauty and health. Currently, in many countries, a smile is considered beautiful if it imitates a natural appearance, with clear, well-aligned teeth and defined anatomical shapes. Enamel microabrasion is one technique that can be used to correct discolored enamel. This technique has been elucidated and strongly advocated by Croll and Cavanaugh since 1986, and by other investigators who suggested mechanical removal of enamel stains using acidic substances in conjunction with abrasive agents. Enamel microabrasion is indicated to remove intrinsic stains of any color and of hard texture, and is contraindicated for extrinsic stains, dentinal stains, for patients with deficient labial seals, and in cases where there is no possibility to place a rubber dam adequately during the microabrasion procedure. It should be emphasized that enamel microabrasion causes a microreduction on the enamel surface, and, in some cases, teeth submitted to microabrasion may appear a darker or yellowish color because the thin remaining enamel surface can reveal some of the dentinal tissue color. In these situations, according to Haywood and Heymann in 1989, correction of the color pattern of teeth can be obtained through the use of whitening products containing carbamide peroxide in custom trays. A considerable margin of clinical success has been shown when diligence to at-home protocols is achieved by the patient and supervised by the professional. Considering these possibilities, this article presents the microabrasion technique for removal of stains on dental enamel, followed by tooth bleaching with carbamide peroxide and composite resin restoration, if required.

Evaluating the bonding of two adhesive systems to enamel submitted to whitening dentifrices.

The aim of this study was to evaluate by micro-shear bond strength test, the bond strength of composite resin restoration to enamel submitted to whitening dentifrices. Forty bovine teeth were embedded in polystyrene resin and polished. The specimens were randomly divided into eight groups (n=5), according to the dentifrice (carbamide peroxide, hydrogen peroxide and conventional dentifrice) and the adhesive system (Prime & Bond 2.1 and Adper Single Bond 2). Dentifrice was applied for 15 minutes a day, for 21 days. Thirty minutes after the last exposure to dentifrice, the samples were submitted to a bonding procedure with the respective adhesive system. After that, four buttons of resin were bonded in each sample using transparent cylindrical molds. After 24 hours, the teeth were submitted to the micro-shear bond strength test and subsequent analysis of the fracture mode. Data were submitted to analysis of variance and Fisher's PLSD test (alpha = 0.05). The micro-shear bond strength showed no difference between adhesives systems but a significant reduction was found between the control and carbamide groups (p = 0.0145) and the control and hydrogen groups (p = 0.0370). The evaluation of the failures modes showed that adhesive failures were predominant. Cohesive failures were predominant in group IV The use of dentifrice with peroxides can decrease bonding strength in enamel.

Reestablishment of occlusion with prosthesis and composite resin restorations.

Here, we present a case report on prosthetic reconstruction of posterior teeth and composite resin restoration of anterior teeth yielding considerable esthetic improvement, reestablishment of disocclusion guides and function.

Correlation of the hybrid layer thickness and resin tags length with the bond strength of a self-etching adhesive system.

The objective of this study was to measure the thickness of the hybrid layer (HLT), length of resin tags (RTL) and bond strength (BS) in the same teeth, using a self-etching adhesive system Adper Prompt L Pop to intact dentin and to analyze the correlation between HLTand RTL and their BS. Ten human molars were used for the restorative procedures and each restored tooth was sectioned in mesio-distal direction. One section was submitted to light microscopy analysis of HLT and RTL (400x). Another section was prepared and submitted to the microtensile bond test (0.5 mm/min). The fractured surfaces were analyzed using scanning electron microscopy to determine the failure pattern. Correlation between HLT and RTL with the BS data was analyzed by linear regression. The mean values of HLT, RTL and BS were 3.36 microm, 12.97 microm and 14.10 MPa, respectively. No significant relationship between BS and HLT (R2= 0.011, p>0.05) and between BS and RTL (R2= 0.038) was observed. The results suggested that there was no significant correlation between the HLT and RTL with the BS of the self-etching adhesive to dentin.

Effect of curing lights and bleaching agents on physical properties of a hybrid composite resin.

UNLABELLED: The aim of this in vitro study was to evaluate the microhardness (MH) and diametral tensile strength (DTS) of a minifill hybrid composite (Filtek Z250, 3M ESPE), polymerized with halogen lamp or second generation light-emitting diode (LED), submitted to different bleaching agents. Composite resin specimens were randomly polymerized according to experimental groups (halogen, 550 mW/cm(2)/20 seconds; LED, 550 mW/cm(2)/25 seconds) and subdivided into three subgroups (N=8): A, without bleaching (control); H, 35% hydrogen peroxide; and C, 16% carbamide peroxide. After that, the MH test and DTS test were performed. Two-way analysis of variance (whitening x light) and Tukey's tests (alpha=5%) were performed. For DTS, there were no statistical differences among the bleaching agents and the control group; however, the halogen group presented statistically lower DTS (p<0.05) than the LED group. For the MH test, the carbamide peroxide group presented statistically lower MH means (p<0.05) than the control groups, and there were no statistical differences among the light-curing units. Sixteen percent carbamide peroxide reduced the MH of the hybrid composite tested. The second generation LED presented a performance similar to or better than the halogen lamp for hardness and DTS, respectively. CLINICAL SIGNIFICANCE: Repolishing of minifill hybrid composite is suggested, as the alteration caused after the contact with 16% carbamide peroxide was limited to the material surface. The second generation light-emitting diode is a good option for a curing light device when the polymerization initiator of composite resin is camphorquinone.

The influence of temperature of three adhesive systems on bonding to ground enamel.

UNLABELLED: This study evaluated the microtensile bond strength test (pT), micromorphology of resin-enamel interface (RET) and etching patterns (EP) promoted by the etch-and-rinse adhesive, Prime&Bond NT (PB), and two self-etching adhesives, Clearfil SE Bond (SE) and Adper Prompt L-Pop (APR), to ground bovine enamel surfaces, when applied at temperatures of 5 degrees C (C), 40 degrees C (H) and 20 degrees C (R). MATERIALS AND METHODS. Sixty-three bovine incisors were randomly divided into nine experimental groups (n = 7) according to adhesive systems and temperatures. The buccal enamel surfaces were flattened with 600-grit SiC paper and abraded with a diamond bur under water-cooling. The adhesive systems were applied according to the manufacturer's instructions. After the restorative procedures, the specimens were sectioned into five slabs. Four slabs were prepared for pT and one for interface analysis. For etching pattern analysis, the remaining 16 bovine enamel fragments were used (n = 2). The adhesives were applied and the surfaces were rinsed with organic solvents after application. The specimens for RET and EP analysis were prepared for SEM analysis. RESULTS: No significant differences among the adhesives were found at R temperature. However, at 5 degrees C, PB and APR presented lower bond strength than SE. At H temperature, higher bond strength was observed for PB than for APR and SE. At C and H temperature, formation of the interdiffusion zone was impaired and the treated enamel surfaces presented an undefined EP. CONCLUSION: The variation of temperature of bonding agents affected microT, RET and EP for all materials tested.

Length of resin tags in pit-and-fissure sealants: all-in-one self-etching adhesive vs phosphoric acid etching.

PURPOSE: To investigate the penetration (tags) of adhesive materials into enamel etched with phosphoric acid or treated with a self-etching adhesive, before application of a pit-and-fissure sealant. MATERIALS AND METHODS: The sample comprised six study groups with six specimens each. Before pit-and-fissure sealing with the materials Clinpro SealantTM (Groups I and II), Vitro Seal ALPHA (Groups III and IV) and Fuji II LC (Groups V and VI), the teeth in Groups I, III, and V were etched with 35% phosphoric acid for 30 seconds. Teeth in Groups II, IV, and VI received application of the self-etching adhesive Adper Prompt L-Pop. The treated teeth were sectioned buccolingually, ground to 100-microm thickness, decalcified, and analyzed by conventional light microscopy at 400x magnification. RESULTS: The teeth etched with phosphoric acid exhibited significantly greater penetration than specimens treated with self-etching adhesive. CLINICAL SIGNIFICANCE: When compared with enamel treated with a self-etching adhesive, the penetration (tags) of adhesive materials into enamel was greater when applied on enamel etched with phosphoric acid.

In vitro-evaluation of secondary caries formation around restoration.

The objective of this in vitro study was to evaluate demineralization around restorations. Class V preparations were made on the buccal and lingual surfaces of each tooth. TPH (Group 1), Fuji II LC (Group 2), Tetric (Group 3), Dyract (Group 4), GS 80 (Group 5) and Chelon Fil (Group 6) were randomly placed in equal numbers of teeth. The teeth were submitted to a pH-cycling model associated with a thermocycling model. Sections were made and the specimens were examined for the presence of demineralization under polarized light microscopy. Demineralization was significantly reduced with Chelon Fil (Group 6). Furthermore, a similar inhibitory effect on the development of demineralization was observed in Groups 2, 4 and 5.

Clinical assessment of postoperative sensitivity in posterior composite restorations.

This incidence of postoperative sensitivity was evaluated in resin-based posterior restorations. Two hundred and ninety-two direct restorations were evaluated in premolars and molars. A total of 143 Class I and 149 Class II restorations (MO/OD and MOD) were placed in patients ranging in age from 30 to 50 years. After the cavity preparations were completed, a rubber dam was placed, and the preparations were restored using a total-etch system (Prime & Bond NT) and a resin-based restorative material (TPH Spectrum). The patients were contacted after 24 hours and 7, 30 and 90 days postoperatively and questioned regarding the presence of sensitivity and the stimuli that triggered that sensitivity. The Chi-square and Fisher's Exact Test were used for statistical analysis. Evaluation at 24 hours after restorative treatment revealed statistically significant differences among the types of cavity preparations restored and the occurrence of postoperative sensitivity (p = 0.0003), with a higher frequency of sensitivity in Class II MOD restorations (26%), followed by Class II MO/DO (15%) and Class I restorations (5%). At 7, 30 and 90 days after restorative treatment, there was a decrease in the occurrence of sensitivity for all groups. The percentage of sensitivity among the groups was not significantly different. This study shows that the occurrence of sensitivity is correlated with the complexity of the restoration.

Considerations about enamel microabrasion after 18 years.

PURPOSE: To review of the current status of enamel microabrasion method and its results 18 years after the development and application of this method. METHODS: A technique performing enamel microabrasion with hydrochloric acid mixed with pumice and other techniques employing a commercially available compound of hydrochloric acid and fine-grit silicon carbide particles in a water-soluble paste have been described. Much has been learned about the application of this esthetic technique, long-term treatment results and microscopic changes to the enamel surface that has significant clinical implications. The latest treatment protocol is presented and photographic case histories document the treatment results. Clinical observations made over 18 years are discussed. RESULTS: According to our findings, the dental enamel microabrasion technique is a highly satisfactory, safe and effective procedure.

The influence of time interval between bleaching and enamel bonding.

OBJECTIVES: The purpose of this study was to investigate the penetration of a conventional adhesive material into enamel bleached with 16% carbamide peroxide and 38% hydrogen peroxide using optical light microscopy. METHODS: Extracted human teeth were randomly divided into eight experimental groups with six specimens each, according to the bleaching material and time interval after bleaching and before the bonding procedure. Groups were designated as follows: control group, restorations in unbleached teeth; restorations performed immediately after bleaching; restorations performed 7 days after bleaching; restorations performed 14 days after bleaching; and restorations performed 30 days after bleaching. The length of resin tags was measured with an Axiophot photomicroscope at 400x magnification for the calculation of the proportion of tags of study groups compared to the respective control groups. Analysis of variance was applied for comparison between groups; data were transformed into arcsine (p < 0.05). RESULTS: The specimens of experimental groups, in which restorations were performed 7, 14, and 30 days after bleaching, showed better penetration of adhesive material into enamel than specimens restored immediately after bleaching. There was no statistically significant difference between the bleaching materials employed or in the interaction between bleaching agent and time interval. CONCLUSIONS: This suggests that a time interval of at least 7 days should be allowed between enamel bleaching and placement of adhesive bonding agents for accomplishment of composite resin restorations. CLINICAL SIGNIFICANCE: Establishment of adequate time after bleaching is fundamental to allow the normal penetration of a one-bottle conventional adhesive onto the enamel surface.

The effect of temperature on self-etching adhesive penetration.

The purpose of this study was to investigate the penetration of an aggressive self-etching adhesive system at refrigerated and room temperatures into ground and unground enamel surfaces. Thirty extracted human teeth were used to measure adhesive penetration into enamel by light microscopy analysis (x400). The unground enamel surfaces were cleaned with pumice and water using a rotary dental brush. For each specimen, part of the unground enamel was manually ground and part was kept intact. A self-etch adhesive was evaluated for its ability to penetrate ground and unground enamel surfaces at room temperature (25 degrees C), at 30 minutes after removal from the refrigerator, and immediately after removal from the refrigerator (6 degrees C). Data were analyzed using variance and the Tukey test, which revealed significant differences in length of penetration of this material when applied on ground and unground enamel surfaces and between the different temperatures used (P > .05). The self-etching system used in this study had significantly lower penetration into unground enamel and at 6 degrees C (P < .05). No statistical difference was found between the interactions of these factors. It was concluded that the self-etching system produced the best penetration into ground enamel surface at room temperature (25 degrees C) and at 30 minutes after removing the specimens from the refrigerator.

Effect of 10% carbamide peroxide dental bleaching on microhardness of filled and unfilled sealant materials.

PURPOSE: The purpose of this study was to quantitatively evaluate the effect of 10% carbamide peroxide on the microhardness of pit and fissure sealant materials. METHODS: Fluroshield, Vitroseal Alfa, and one unfilled (Clinpro) sealants were placed in Teflon matrices (4 mm in diameter by 2 mm in height) and polymerized for 40 seconds. A total of 20 specimens were prepared for each material, in which half were assigned as the control group (stored in artificial saliva and no bleaching treatment). For the remaining half, Clarigel Gold bleaching agent (10% carbamide peroxide) was placed over the specimen surface for 4 hours/day during 4 weeks. When specimens were not under bleaching treatment, they were kept in artificial saliva. Afterwards, specimens were subjected to Knoop microhardness testing using a 25-g load for 5 seconds. Five measurements were made on the sealants' surfaces and then calculated in Knoop hardness values. The data were statistically analyzed by two-way analysis of variance and Tukey's tests with a 5% confidence level. RESULTS: The results of this in vitro study showed that the application of a carbamide peroxide-based bleaching material significantly affected the microhardness values of filled sealant materials. The bleaching agent did not affect the microhardness of the unfilled sealant. CLINICAL SIGNIFICANCE The results of this in vitro study suggest that the bleaching agents altered the surface hardness of filled sealant restorative materials. This could possibly lead to increased wear and surface roughness.

Longitudinal photographic observation of the occurrence of bubbles in pit and fissure sealants.

UNLABELLED: The purpose of this study was to employ photographic evaluation to observe the presence or absence of bubbles in pit and fissure sealants Concise and Prisma Shield, at 7 days, 18 months, 36 months and 11 years after accomplishment of treatment. METHODS: A hematoxylin-based staining solution was applied to the occlusal surface at the study periods, which allowed assessment of the sealing material on the surface. All occlusal surfaces were photographed and the photographs corresponding to each period were subjected to photographic evaluation. RESULTS: There was statistically significant difference only at 18 months, with a significantly higher number of specimens with bubbles for the Prisma Shield sealant compared to the Concise, whereas the groups were similar at all other study periods. On the other hand, separate analysis of subsequent periods of the sealants did not reveal any significant difference. CONCLUSIONS: According to the results of the present longitudinal investigation, it may be concluded that the sealing materials showed that bubbles came into and went out with time. However, this fact did not interfere with its clinical purpose, provided the remaining material covers the expected region of pits and fissures.

Hybrid layer thickness and resin tag length of a self-etching adhesive bonded to sound dentin.

OBJECTIVES: the purpose of this study is to employ optical microscopy to measure the thickness of the hybrid layer and the penetration (tags) of an aggressive self-etching adhesive system into sound dentin. METHODS: occlusal cavities were prepared in 40 extracted human posterior teeth. The prepared teeth were randomly assigned to four experimental groups with 10 specimens each. The self-etching adhesive system Adper Prompt L-Pop was applied to the dentin surface as follows: Group 1: cavosurface enamel was etched for 60 s and dentin for 20 s with 35% phosphoric acid gel, immediately followed by application of the self-etching adhesive with a brush to the entire cavity for 15 s; Groups 2, 3, and 4: no pre-etching was performed, and the self-etching adhesive was applied to both enamel and dentin for 15, 30 and 45 s, respectively. After curing, the cavities were filled with composite resin Filtek Z250. Afterwards, the teeth were decalcified and the restorations were carefully removed for later embedding in paraffin. The specimens were serially sectioned at 6 microm of thickness and sequentially mounted in glass slides. These sections were stained with Brown and Brenn staining for posterior analysis and measurement of the hybrid layer and resin tags on a light microscope with a micrometric ocular 40/075. The results were submitted to analysis of variance at the 5% level. RESULTS: whenever there was significance, the Tukey test was applied at the 5% level. The specimens receiving application of acid etching before the self-etching adhesive displayed a larger thickness of the hybrid layer; on the other hand, specimens receiving only application of the self-etching adhesive on dentin for 15, 30 and 45 s exhibited similar thickness of the hybrid layer. As regards the resin tags, no statistically significant differences could be found between the study groups. CONCLUSIONS: it could be concluded that the increase in the time of application of the self-etching adhesive Adper Prompt L-Pop did not significantly influence the formation and thickness of hybrid layer, as well as its penetration into the sound dentin surface.