Biomedical subjects

Sylvio Monteiro

Publications and source records attributed to Sylvio Monteiro.

14 recordsLinked to original sources

PubMed2006

Dentin bond strengths of simplified adhesives: effect of dentin depth.

The objective of this study was to compare the shear bond strength of 3 simplified adhesive systems applied on shallow vs deep dentin. For superficial dentin, 30 human molars were sectioned with a diamond saw to expose dentin immediately below the dentoenamel junction. For deep dentin, 30 molars were sectioned 3 mm below the dentoenamel junction. The teeth were mounted, polished to 600-grit, and randomly assigned to 3 groups (n=10): Single Bonda and OptiBond Solo, total-etch adhesives, and Clearfil Liner Bond 2V, a self-etching primer adhesive. Adhesives were applied, the restorative material Filtek Z250 inserted in a No. 5 gelatin capsule, and light-cured. After 24 hours in water at 37 degrees C, shear bond strength was measured with an Instron at 5 mm/min. The data were analyzed with 2-way ANOVA and Duncan's post-hoc test. The results showed the following shear bond strengths (mean +/- SD in MPa): Single Bond/superficial dentin = 22.1 +/- 2.8; Single Bond/deep dentin = 14.2 +/- 7.0; OptiBond Solo/superficial dentin = 18.9 +/- 4.1; OptiBond Solo/deep dentin = 18.4 +/- 4.8; Clearfil Liner Bond 2V/superficial dentin = 21.0 +/- 7.4; Clearfil Liner Bond 2V/deep dentin = 17.6 +/- 5.9. There were no significant differences between mean shear bond strength for the factor "adhesive system" (P>.822). The Duncan's test showed that Single Bond resulted in higher shear bond strength on superficial dentin than on deep dentin. The mean shear bond strength for Clearfil Liner Bond 2V and OptiBond Solo were not influenced by dentin depth. When data were pooled for dentin depth, deep dentin resulted in statistically lower bond strengths than superficial dentin (P<.01). The influence of dentin depth on shear bond strength depends on the specific composition of the dentin adhesive.

Analysis of Variance↗

PubMed2005

Clinical strategies for success in proximoincisal composite restorations. Part II: Composite application technique.

UNLABELLED: Reproducing the form, function, and optical characteristics of natural dental structures with direct composites in large and moderately large proximoincisal (Class IV) restorations represents a great challenge for clinicians in general. Understanding color is fundamental to achieving success when restoring these defects, as was discussed in Part I of this two-part article (Volume, 16, Number 6). The proper restoration of the functional lingual contour is also a challenge that cannot be overcome without close attention to the restorative technique. In this second article, the composite application technique is discussed and presented in detail. Clinical photographs illustrate the proposed technique. CLINICAL SIGNIFICANCE: The proposed clinical protocol, including a try-in of the shades in a mock-up restoration to more accurately define color and shape, and a silicone guide to transfer the lingual and proximoincisal contour of the mock-up to the final restoration, is of great help to successfully restore proximoincisal defects.

Clinical Protocols↗

PubMed2005

Esthetic noncarious Class V restorations: a case report.

UNLABELLED: When restoring anterior and posterior teeth affected by noncarious cervical lesions, many clinicians overlook the etiologic factors responsible for the lesions' development, resulting in frequent restorative failures. The treatment approach for noncarious cervical lesions must not be based only on restorative procedures since a variety of causative and aggravating factors are related to their formation. This article discusses a treatment protocol and techniques for the restoration of noncarious Class V lesions and presents a clinical case in which esthetic restorations are achieved. CLINICAL SIGNIFICANCE: Treatment options for noncarious Class V lesions can range from simply eliminating the causative factors of the lesions and regularly monitoring their progression to specific restorative procedures. Resin composites are the best materials for restoring cervical defects owing to their bonding ability, physical properties, and esthetic potential. A straightforward technique for the successful restoration of noncarious Class V lesions is presented.

Bruxism↗

PubMed2004

Flowable composites as "filled adhesives:" a microleakage study.

OBJECTIVE: The purpose of this in vitro study was to investigate the microleakage at dentin margins of a flowable resin composite associated with an adhesive, either light cured separately or co-cured, in Class V cavities. MATERIALS AND METHODS: Twenty four recently extracted human molars were prepared with standardized box-shaped Class V cavities of 3.0 mm (mesial-distal), 2.0 mm (occlusal-gingival), and 2.0 mm depth with margins located on enamel and dentin/cementum on the buccal or lingual surfaces. The cavities were randomly assigned into three groups (n=8): Group I - Single Bond + Filtek Z250 (control); Group II - Single Bond + Filtek Flow (light cured separately) + Filtek Z250; and Group III - Single Bond + Filtek Flow co-cured (light cured simultaneously) + Filtek Z250. After being immersed in tap water for 24 h, the specimens were thermocycled (1000x, 5 degrees -55 degrees C, 30 sec dwell time) and immersed in a 0.5% basic fuchsine solution for 24 h. The restorations were sectioned longitudinally and gingival margins were evaluated for microleakage using a 0-4 scale. Data were subjected to the Kruskal-Wallis test at p<0.05. RESULTS: A statistically significant difference at p = 0.0044 between Groups 1 and 3 and Groups 2 and 3 was observed. Although Group 2 performed slightly better than Group 1, no significant difference was observed. CONCLUSION: The use of a flowable resin composite cured simultaneously with an adhesive yielded the worst results in this study. As no statistical differences were seen between Groups 1 and 2, the use of a flowable composite as a means of minimizing microleakage at dentin margins may be questioned.

Adhesives↗

PubMed2004

In situ effect of 10% carbamide peroxide on resin-dentin bond strengths: a novel pilot study.

PURPOSE: This pilot study used a novel study design to evaluate the effect of a 10% carbamide peroxide bleaching gel on the bond strength of a resin-based composite system to dentin. MATERIALS AND METHODS: Dentin disks were obtained from human third molars, polished to 600 grit, and mounted on the palatal aspect of a removable orthodontic retainer. Two disks were exposed to a 10% carbamide peroxide bleaching gel for 2 h/d for 21 days, whereas two disks were not treated and served as controls. A retainer was worn by the participant regardless of whether bleaching was used, simulating the action of the saliva/oral fluids on the dentin specimens. After the treatment phase, the dentin disks were retrieved and a resin-based composite system was applied to the specimens following manufacturer's instructions. Composite dentin "sticks" were obtained and tested in microtensile mode. Bond strength values were obtained for treated (n = 20) versus nontreated (n = 26) dentin and were analyzed statistically. RESULTS: Mean bond strengths values (SD) were 29.9 MPa (6.2) and 39.2 MPa (5.8) for treated and nontreated dentin specimens, respectively (p < .001). CONCLUSION: The results of this study suggest that nightguard (home) bleaching with 10% carbamide peroxide for 2 h/d for 21 days significantly affects resin-dentin bond strengths when dentin is exposed to bleaching material. CLINICAL SIGNIFICANCE The findings of this novel pilot study imply that dentin bonding, such as to exposed root surfaces and cervical areas of the teeth, should not be performed immediately after bleaching with 10% carbamide peroxide.

Adult↗

PubMed2004

Clinical strategies for success in proximoincisal composite restorations. Part I: Understanding color and composite selection.

The restoration of proximoincisal (Class IV) defects with direct resin-based composites requires attention to many technical and artistic details. This article is the first of a series of two articles that aim at presenting clinical strategies for optimal success when direct resin-based composites are used for the restoration of moderate or large proximoincisal defects. Concepts of natural anatomy, color as it relates to dental structures, and composite selection are discussed in this article and are illustrated with a preclinical exercise and two clinical cases in which these concepts are applied.

Acrylic Resins↗

PubMed2004

Effect of posterior resin composite placement technique on the resin-dentin interface formed in vivo.

OBJECTIVE: The aim of this study was to evaluate the morphology of the resin-dentin interface formed in vivo with two posterior resin composite placement techniques (incremental and bulk). METHOD AND MATERIALS: After approval from the patients, 12 Class II cavities with margins in enamel (2.5 x 2.5 x 4.5 mm) were prepared in caries-free premolars scheduled to be extracted for orthodontic reasons (n = 6). The cavities were restored with Single Bond + Filtek P60 as a bulk condensable technique or Single Bond + Filtek Z250 as an oblique incremental technique. After 1 week, the teeth were extracted with minimal trauma to the restored area. After the teeth were sectioned, a polyvinyl siloxane impression was taken from the resin-dentin interface to control for artifacts created during preparation for scanning electron microscopy. The specimens were subsequently processed for and observed under a scanning electron microscope to assess gap formation. RESULTS: The mean percentage of gap formation was 6.1% for teeth restored with the incremental placement technique and 18.7% for teeth restored with the bulk placement technique. The difference was statistically significant. CONCLUSION: The incremental placement of posterior resin composites may still provide better seal than the new bulk condensable technique.

Bicuspid↗

PubMed2004

Bonding to cervical sclerotic dentin: effect of acid etching time.

PURPOSE: The aim of this in vitro study was to evaluate the microtensile bond strengths (MTBS) of two total-etch one-bottle adhesive systems to natural cervical lesions with 2 different etching times (15 s vs 30 s). MATERIALS AND METHODS: Thirty-two human canines and premolars with saucer-shaped noncarious cervical defects were cleaned and randomly assigned to 4 groups. The adhesive systems - Single Bond (SB; 3M ESPE) or OptiBond Solo Plus (OP; Kerr) - were applied on cervical dentin after acid etching with the proprietary acid gel (35% or 37.5% phosphoric acid) for 15 s (manufacturer's instruction) or for 30 s. The respective hybrid composite was inserted in three increments and light cured. After 24 h water storage, the specimens were cut perpendicularly with a low-speed diamond saw (Isomet) to obtain slices with a cross section of ca 0.8 mm. After that, the slices were trimmed with a diamond bur to obtain a surface area of 0.7 +/- 0.05 mm2 (n = 12). MTBS was measured in a Bencor device with an Instron machine at a crosshead speed of 0.5 mm/min. The data were subjected to two-way ANOVA and Tukey's LSD post-hoc test (p < 0.05). RESULTS: MTBS are given in MPa (mean +/- SD), where means with the same superscript letter are not statistically different at p < 0.05: OP15 = 30.9 +/- 8.8ab, SB15 = 25.6 +/- 9.6bc, OP30 = 19.0 +/- 4.8c, SB30 = 35.9 +/- 11.0a. When data were pooled for "adhesive system", SB resulted in statistically higher bond strengths than OP (p < 0.043). "Acid etching time" had no significant effect (p < 0.766), but the interaction of the two main factors yielded significant differences (p < 0.0001). Extending etching time to 30 s resulted in a more predictable bond to noncarious cervical sclerotic dentin with SB, but resulted in lower MTBS with OP. CONCLUSION: Composite bonding to cervical sclerotic noncarious dentin may depend on acid demineralization capacity and bonding system. Knowing the etching demineralization rates of the commercially available acid etching seems to be an important factor for selecting the best acid-etching time of cervical sclerotic dentin.

Acid Etching, Dental↗

PubMed2003

Using opaquers under direct composite resin veneers: an illustrated review of the technique.

UNLABELLED: In restorative dentistry direct composite resin materials can be used to conservatively resolve many esthetic problems. Opaque resins are often necessary to mask discolorations and/or dark backgrounds when restoring anterior teeth. This article presents a direct composite resin veneer technique using opaquers. Potential problems with the tone of restorations after the use of opaquers are discussed. Advantages, limitations, and the clinical technique are presented. Training, as well as attention to the technique, contributes to an acceptable result. CLINICAL SIGNIFICANCE: Resinous opaquers can be used as a valid adjunct to the direct composite resin veneer technique when conservatively restoring dark teeth.

Child↗

PubMed2003

Tooth fragment reattachment: fundamentals of the technique and two case reports.

Coronal fractures must be approached in a methodical and clinically indicated way to achieve successful restoration. One option for treatment is reattachment of the dental fragment. Reattachment creates a very positive emotional response in the patient and simplifies the maintenance of the patient's original occlusion. This article discusses dental fragment reattachment techniques and presents clinical cases of coronal fracture involving enamel, dentin, and pulpal exposure.

Adolescent↗

PubMed2003

Direct adhesive restoration of anterior teeth: Part 2. Clinical protocol.

Contemporary adhesive restorations allow clinicians to deliver minimally invasive, functional, and aesthetic treatment for compromised dentition in the anterior and posterior regions. Part 1 of this article discussed the state-of-the-art relating to composite restorations, both in situations deemed to be relatively uncomplicated and those that are more complicated. This second part discusses the clinical protocol for the placement of direct composite materials as well as the tooth preparation considerations that must be addressed when providing minimally invasive treatment options.

Clinical Protocols↗

PubMed2002

Effect of bleaching agents on the hardness and morphology of enamel.

PURPOSE: The goal of the present laboratory study was to analyze the effect of two home bleaching agents (Opalescence 10%, Ultradent, and Hi-Lite II, Shofu) as well as the separate solutions of 10% carbamide peroxide primary components (3% hydrogen peroxide and 7% urea) on enamel microhardness and surface morphology. MATERIALS AND METHODS: Thirty human molars stored in water for no longer than 3 months were selected. Their facial and lingual surfaces were embedded in acrylic resin, and the specimens were polished with up to 600-grit sandpaper. The 30 molar sections were divided into five groups as per treatment modality (n = 6); group 1, 10% carbamide peroxide bleach with carbopol (Opalescence, Ultradent); group 2, oxygen-free gel bleach (Hydroxylite, Hi-Lite II, Shofu); group 3, 3% hydrogen peroxide with carbopol (Dermus Pharmacy, Florianópolis, SC, Brazil); group 4, 7% urea treatment (Dermus Pharmacy); and control, group 5, artificial saliva (Dermus Pharmacy). Prior to treatment, six indentations (Vickers) were made on each of the six surfaces in each group under a load of 100 g for 30 seconds. Bleaching procedure was conducted for 3 hours per day for 2 weeks, the control group excepted. Following each bleaching session, the specimens were washed with deionized water and kept in artificial saliva at 37 degrees C, this solution being changed daily. Pre- and post-treatment microhardness data were analyzed using a two-way analysis of variance. In a similar way, 30 other specimens underwent the same procedures. After the bleaching period, the samples were observed under the scanning electron microscope. RESULTS: Specimens submitted to bleaching treatment with 3% hydrogen peroxide gel as described in this study showed a significant reduction of surface microhardness (p < .0001). The other treatment modalities had no effect on surface microhardness. No morphologic alterations were observed on enamel submitted to bleaching gel of 10% carbamide peroxide (Opalescence), oxygen-free gel (Hi-Lite II, Shofu), or 7% urea solution compared with the control (artificial saliva). However, the specimens bleached for 3 hours per day for 2 weeks with 3% hydrogen peroxide gel presented areas of mild erosion. The effect, nevertheless, was not uniform, occurring with varying intensity on all samples of enamel bleached with 3% hydrogen peroxide. CLINICAL SIGNIFICANCE: Bleaching treatment conducted with two home bleaching agents (Opalescence 10%, Ultradent, and Hi-Lite II, Shofu) had no adverse effects on enamel microhardness or on surface morphology. Bleaching with 3% hydrogen peroxide can have a negative effect on enamel hardness and surface morphology when performed as described in this study.

Acrylic Resins↗

PubMedDate not supplied

Dentin bonding: effect of degree of mineralization and acid etching time.

This in vitro study verifies whether there are differences between bonding to hypermineralized dentin and normal dentin and if longer acid etching can improve the bond strength to this modified substrate without damaging the bond to normal dentin. Forty-two extracted human molars with chronic occlusal caries were transversally cut with a diamond saw under refrigeration. The occlusal surfaces were ground until the carious lesion was removed, exposing the sclerotic dentin in the center and polished to 600/grid. A 35% phosphoric acid (3M) was applied for 15 seconds in 15 specimens. SingleBond (3M) adhesive system was applied and a hybrid resin composite (Filtek Z250, 3M) was inserted in four 1-mm increments and light-cured. The remaining 15 molars were prepared in the same manner, but with an acid etching time of 30 seconds. After 24 hours in water, the specimens were cut in two perpendicular directions to obtain a cross section of approximately 0.7 mm2 (n=25). A visual examination was conducted to select sticks between the two groups: sclerotic dentin (G15S or G30S) and normal dentin (G15N or G30N). Sticks without 100% sclerotic dentin (translucent area) or those with normal areas were not tested. Two-way ANOVA computed the mu-TBS data taking into consideration dentin type and acid etching time. The dentin Knoop hardness number (KHN) of the sticks was verified. A t-test compared the KHN data between sclerotic and normal dentin. Twelve additional molars (n=6) were prepared to observe the interface under a SEM. The mean (+/- SD) microtensile bond strengths (mu-TBS) were: G15S=56.4(+/- 14.9), G15N=69.7(+/- 17.2), G30S=63.2(+/- 15.6) and G30N=67.7(+/- 13.3). Two-way ANOVA showed higher mu-TBS to normal dentin than sclerotic dentin. Duncan's Post Hoc showed G15N had higher mean mu-TBS than G15S. Other comparisons were not significantly different. The t-test showed statistically higher microhardness in sclerotic dentin than in normal dentin (p<0.0001). The hybrid layer (HL) formation was observed in all specimens without gap formation in any region. In sclerotic dentin (G15S), the HL was very thin, with minimal resin tags in the dentinal tubules and, when present, they were shorter. Doubling the etching time (G30S) resulted in more resin tags with an HL formation on peritubular dentin. The HL on normal dentin was thicker when it was acid etched for 30 seconds (G30N). Numerous resin tags were present with both etching times. The results suggest that the higher mineral amount in sclerotic dentin makes it difficult to bond to this substrate, resulting in a lower mu-TBS. However, doubling the etching time resulted in mu-TBS similar to normal dentin.

Acid Etching, Dental↗

PubMedDate not supplied

Dentin bond strength of self-etching primers/adhesives.

This study compared the shear bond strengths (SBS) to dentin achieved with six self-etching systems and one total-etch one-bottle adhesive system. Seventy freshly extracted bovine incisors were mounted in acrylic molds and the facial surfaces ground to expose middle dentin, which was polished by 600-grit sand paper. The incisors were randomly assigned to groups (n=10): Adper Prompt Self-Etch Adhesive, 3M-ESPE (ADP) and One-Up Bond F, Tokuyama (OU) as self-etching adhesives; AdheSE, Ivoclar-Vivadent (ADH), Clearfil SE Bond, Kuraray (SE), Optibond Solo Plus-Self-Etch, Kerr (OP) as self-etching primers, Tyrian SPE, BISCO (TY) as a self-priming etchant and Single Bond, 3M-ESPE (SB), a total-etch one-bottle adhesive served as a control. All adhesives were applied according to the manufacturers' instructions with the respective hybrid composites. The specimens were thermocycled for 500 cycles (5 degrees C to 55 degrees C), then loaded to failure in an Instron Universal Testing Machine at a crosshead speed of 0.5 mm/minute. Mean bond strengths were analyzed with one-way ANOVA, followed by a Duncan's post hoc test. SBS (mean +/- SD) were: ADH = 13.2 (+/- 5.3)b;ADP = 6.8 (+/- 4.4)c; OP = 18.2 (+/- 3.8)a; OU = 3.5 (+/- 1.5)c; SB = 12.2 (+/- 4.2)b; SE = 12.4 ( +/- 4.0)b; TY = 5.5 (+/- 1.4)c. Superscript letters indicate Duncan's homogeneous subsets. The self-etching adhesives OU and ADP and the self-priming etchant TY resulted in lower dentin SBS. OP resulted in the highest mean dentin SBS, while the other materials tested in this study (SE and ADH) presented similar dentin SBS to a total-etch one-bottle bonding system (SB).

Acid Etching, Dental↗