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At least 613 records · Page 34Linked to original sources

PubMed2001

Aetiology of abfraction lesions.

The aetiology of abfraction lesions is complex. Most evidence indicates that physical loading forces are a major contributing factor, although they are unlikely to be entirely responsible. Intraoral chemical influences and toothbrush abrasion, combined with the dynamics of inter-occlusal activity such as chewing, swallowing, and parafunction, lead to stress corrosion and may contribute to abfraction lesions. The multifactorial aetiology that operates in the initiation and progression of these lesions has made investigation difficult. Various theories have been proposed and numerous surveys and studies conducted, but the primary causal factor has yet to be definitively determined. This review concludes that occlusal loading is the initiating factor in the development of abfraction lesions.

Bite Force↗

PubMed2001

Modification of col shape and interproximal area after periodontal surgery associated with the restorative alveolar interface (RAI) technique. Histological study in dogs.

The modification of the col shape and position by the restorative alveolar interface technique (RAI) was studied in the interproximal areas between the mandibular first molars and fourth premolars of 10 dogs. Full thickness flaps were raised to expose the interproximal root surface and alveolar bone crest. The RAI procedure was performed only on the experimental sides and the control areas were the opposite side of the same animal. The animals were sacrificed at zero hour, 7, 14, 21 and 28 days for histological analyses. Approximately 6.0-micron-thick sections were made in buccolingual and mesiodistal directions and stained with hematoxylin-eosin and Mallory for light microscopy analysis. A satisfactory healing process was observed up to the 14th and 21st days which showed a modified col shape. At this time, an inflammatory reaction developed affecting the evolution of the healing. The surgery had probably created conditions for the installation of an inflammatory process resulting from the modified anatomy of the interdental area.

Alveolar Process↗

PubMed1999

A three-year evaluation of restorations placed with a smear-layer-mediated dentin bonding agent in non-carious cervical lesions.

PURPOSE: To evaluate the handling characteristics, clinical behavior, and effectiveness of Coltene ART Bond/Brilliant restorations in mixed Class V preparations in maxillary premolar and canine teeth of adult patients over a three-year period. MATERIALS AND METHODS: Single-center, uncontrolled, clinical evaluation of 50 restorations in 26 patients extending over 36 months. RESULTS: At three years, 34 restorations, or 68% of those originally placed, in 20 patients were available for review. One of the 34 restorations had been lost 15 months after placement. In terms of marginal integrity and staining, anatomic form, surface texture and staining, and postoperative sensitivity, over 90% of the restorations reviewed at three years were rated alpha. Following difficulties in obtaining excellent color match in relation to 14 (28%) of the restorations at the time of placement, only 44% of the restorations were rated alpha at three years. CONCLUSION: It was concluded that with the possible exception of excellent color match, ART Bond/Brilliant restorations may be found to perform favorably in mixed Class V lesions in selected adult patients over a period of at least three years. The findings indicate that resin composite restorations placed with a smear-layer mediated dentin bonding agent may be found to have a favorable clinical outcome in non-carious cervical lesions.

Adult↗

PubMed1999

In vitro leakage of resin-bonded all-porcelain crowns.

PURPOSE: The purpose of this study was to evaluate the sealing ability of single-unit all-porcelain crowns with margins placed in cementum-dentin and luted with two different cementing materials. MATERIALS AND METHODS: Twenty extracted molars, free of caries and restorations, were selected. The sample abutments were prepared in a standardized manner and then divided in two groups (n = 10) at random. Group 1: The cervical margin was located 1 mm below the CEJ and the crowns were luted with EBS Multi (Espe) bonding system in combination with Compolute 1.0 Aplicap (CLA 1.0, Espe) experimental resin cement. Group 2: The cervical margin was placed 1 mm below the CEJ, and Syntac bonding system (Vivadent) and Variolink II resin cement (Vivadent) were used. IPS-Empress (Ivoclar) crowns were made following manufacturer's instructions. After luting procedures and 2,500 thermal cycles (5 degrees and 55 degrees C), the samples were processed and evaluated for marginal leakage at the cervical site. After scoring dye penetration in group 1 and 2 samples, half of the sections were randomly selected in order to evaluate 1) resin cement thickness and 2) hybrid layer formation at the interface between adhesive material and dental substrate. The leakage data were statistically evaluated with the Kruskal-Wallis non-parametric analysis of variance (ANOVA) by ranks with Bonferroni alpha adjustment (p < 0.05). RESULTS: Sixty percent of the group 1 samples and 80% of group 2 showed leakage. In group 1, the dye penetration was often limited to the cervical margin site, while in group 2, it mainly extended to the axial walls. Statistically significant differences between samples of the two groups were not found. Samples of group 1 showed a cement thickness of 82 microns, while 75 microns was found in group 2. A hybrid layer and resin tag formation were evident in group 1. In group 2 samples, the hybrid layer formation was less evident and thinner than in group 1. CONCLUSIONS: The two adhesive systems performed similarly. The cervical margins of single-unit all-porcelain crowns must be considered as one of the weakest areas of this type of esthetic restoration.

Adult↗

PubMed2000

Microleakage and adaptation of Class II packable resin-based composites using incremental or bulk filling techniques.

PURPOSE: To compare the ability of three packable resin-based composite (RBC) systems (ALERT, SureFil, and Solitaire), placed and light-cured in either incremental layers or in bulk, to seal the gingival margin of Class II preparations when the gingival margin is placed apical to the cementoenamel junction. MATERIALS AND METHODS: Packable RBCs were used to restore 60 extracted human premolars with Class II preparations using an incremental-cure technique (each layer no greater than 2 mm in thickness when light-cured) or a bulk-cure technique (n=10). Manufacturers' directions were followed; the cure technique was the only variable. After the restorations were completed, the specimens were thermocycled, stained, sectioned, and viewed under a light microscope for microleakage at the gingival margin. RESULTS: All specimens showed leakage at the gingival margin. No statistically significant difference was found between the bulk-cure and incremental-cure techniques for each of the RBC systems evaluated. ALERT had significantly less leakage than SureFil and Solitaire.

Acid Etching, Dental↗

PubMed2000

Effect of plasma arc curing on the microleakage of Class V resin-based composite restorations.

PURPOSE: To evaluate the effect of plasma arc light-curing on the microleakage of Class V resin-based composite (RBC). MATERIALS AND METHODS: Facial and lingual Class V cavities were prepared at the cemento-enamel junction of extracted third molars. Restorations of the two materials (Z250; Amelogen) were placed, using the supplied dentin adhesives (Single Bond; PQ 1, respectively), and light-cured by either a halogen light curing unit (H) or a plasma arc curing unit (P). After thermal cycling, the teeth were immersed in methylene blue dye, then sections of the restored teeth were visually assessed for leakage. RESULTS: No leakage was observed at the interface between enamel and RBC in any restoration in this study. At gingival margins, the incidence of leakage (slight/severe) was: Z250 H = 2/4, P = 6/6; Amelogen H = 3/4, P = 1/12, where n = 16. The greatest incidence of leakage was observed in restorations cured by the plasma arc method. A two-way ANOVA of leakage data rankings showed curing method to be a significant factor (P = 0.002), restorative material not to be a significant factor (P = 0.24), and no significant interaction between material and curing method (P = 0.38).

Analysis of Variance↗

PubMed2000

Microleakage of resin-based composite restorations with ceramic inserts.

PURPOSE: To evaluate dye penetration of proximal vertical slot resin-based composite (RBC) restorations as a function of cavity size and restorative material employed (RBC, ceramic inserts with low-viscosity resin, and RBC with low-viscosity resin liner). Microleakage was measured using rank scoring and linear measurement of dye penetration and ANOVA and non-parametric tests were used to evaluate the statistical significance of the results. MATERIALS AND METHODS: Ninety erupted crack- and caries-free mandibular third molars, extracted for orthodontic reasons, were used. Proximal vertical slots were prepared on the mesial surfaces of the teeth using diamond instruments at high speed under distilled water coolant. Teeth were placed randomly into nine groups. Three sizes of diamond burs of an ultrasonic cavity preparation system were used under low energy in order to standardize cavity size and shape, each tip size being used in 30 different teeth. The gingival margins were prepared 1 mm above the cemento-enamel junction. Specimens were etched, prepared with bonding agent, restored using three different materials, and immersed in a 50% AgNO3 solution for 8 hrs and sectioned to evaluate the dye penetration. RESULTS: Statistical analysis revealed no statistically significant differences among the nine groups.

Acid Etching, Dental↗

PubMed2001

[Cervical dentine hypersensitivity].

Cervical dentine hypersensitivity is a common problem. When gingiva recession has appeared the root cement can become abraded by several causes and this situation can give pain problems when the tubules do not close. The most important part of the treatment is a good diagnosis and to find and eliminate the predisposing factors. After this has been done it is possible to try to close the dentinal tubulus for which there are several treatments. It is difficult to give a good advice for the treatment of cervical dentine hypersensitivity because research in this field is difficult due to the large amount of variables, the placebo effect and because the lack of a good experimental model.

Dentin Sensitivity↗

PubMed2001

Clinical evaluation of Prime & Bond 2.1 for treating cervical dentin hypersensitivity.

PURPOSE: To evaluate the effectiveness of a "one-bottle" dentin adhesive for reducing or eliminating hypersensitivity in exposed cervical dentin. MATERIALS AND METHODS: Eight patients with hypersensitive teeth were enrolled in this clinical trial. The hypersensitive teeth included a total of 22 premolars and anterior teeth with exposed cervical dentin that was sensitive to cold or other stimuli. A single layer of Prime & Bond 2.1, an acetone-based "one-bottle" adhesive, was applied to the cervical dentin and was light-cured. Sensitivity to compressed air and cold stimuli was determined immediately before and after treatment, and at periods ranging to 24 wks after treatment. Patient responses to the stimuli were timed, and were also evaluated by the use of a visual analogue scale. RESULTS: Application of a single coat of Prime & Bond 2.1 significantly reduced cervical dentin hypersensitivity to both compressed air and cold stimuli immediately after treatment. The reduction in hypersensitivity remained significant at 24 wks after treatment.

Acetone↗

PubMed2001

Microleakage of hydrophilic adhesive systems in Class V composite restorations.

PURPOSE: To investigate the microleakage of four hydrophilic adhesive systems: one "multiple-bottles" (Scotchbond Multi-Purpose Plus); two "one-bottle" (Single Bond, Stae); and one self-etching (Etch & Prime 3.0). MATERIALS AND METHODS: 120 bovine incisor teeth were divided into four groups (n = 30) and Class V cavities were prepared at the cemento-enamel junction. The cavities were restored with the adhesive systems and with Z100 composite. The teeth were thermocycled 1,000 times between 5+/-2 degrees C and 55+/-2 degrees C with a dwell time of 1 min, and then placed in a 2% methylene blue dye (pH 7.0) for 4 hrs, washed and sectioned vertically through the center of the restorations. The qualitative evaluation was made by three examiners who distributed pre-established scores (0-4) for each tooth using a stereomicroscope at x30 magnification. RESULTS: In enamel margins little microleakage was observed and the Kruskal-Wallis analysis did not show differences. In dentin margins the Kruskal-Wallis and multiple comparison analyses were applied: microleakage was significantly greater with Stae (median 3) and Scotchbond MP Plus (median 4). Single Bond (median 1) and Etch & Prime 3.0 (median 2) showed the best results in dentin margins, and the statistical analysis did not demonstrate differences in microleakage among these groups.

Animals↗

PubMedDate not supplied

Effects of delayed polishing on gap formation of cervical restorations.

This study evaluated the effect of polishing after one-day storage in water on the gap formation around a Class V restoration completely bordered by enamel (coronal cavity) using one resin-modified glass ionomer, one compomer and one conventional glass ionomer as a control. The study also examined gap formation of these materials in two different cervical restorations-a cervical cavity incisally bordered by enamel and cervically bordered by dentin and a root surface cavity completely bordered by dentin. When the specimens of the two types of glass-ionomer material were polished immediately after the setting procedure, 100-120 gaps around the coronal restorative cavity were observed. In contrast, only 10-20 gaps were observed when the specimens were polished after one-day storage. Significant differences in the two glass-ionomer restorative materials were observed between immediate polishing and polishing after one-day storage. The compomer not show this pattern. Restorations placed in enamel/dentin and all-dentin gave results similar to those in all-enamel.

Bicuspid↗

PubMed2001

Microtensile bond strength evaluation of three adhesive systems in cervical dentin cavities.

PURPOSE: To evaluate the influence of the orientation of dentinal tubules on the bonding performance, microtensile bond strengths (MTBS) to dentin in cervical dentin cavities were measured for three current bonding systems. MATERIALS AND METHODS: Wedge-shaped cervical cavities (5 x 5 x 3 mm) prepared in extracted human premolars were treated with one of the three adhesive systems, Gluma One Bond, UniFil Bond and Mega Bond in combination with a hybrid-type resin composite. After storage in water for 24 h, the teeth were sectioned longitudinally through the restoration for determination of MTBS, either at the coronal or at the apical wall of the lesion. In an additional group, either the coronal or the apical walls were coated with vaseline prior to adhesive bonding and insertion of the resin composite, and then MTBS was measured. RESULTS: MTBSs (mean +/- SD, MPa) to coronal and apical dentin were 35.1 +/- 19.1 and 16.4 +/- 7.9 for Gluma One Bond, 37.7 +/- 11.5 and 18.6 +/- 8.6 for UniFil Bond, and 27.0 +/- 15.2 and 30.3 +/- 17.0 for Mega Bond, respectively. MTBS to the coronal wall was higher than to the apical wall (p < 0.05) with Gluma One Bond and UniFil Bond, whereas no difference was found with Mega Bond. With all three systems, vaseline coating had no effect on the bond strength (p > 0.05), indicating that the wall-to-wall contraction stresses exerted in the noncoated group had no influence on the bond strength generated. CONCLUSION: In cervical dentin cavities, apart from the individual adhesive's bonding capacity, the dentinal tubular orientation may have an influence on the bond strength.

Adhesives↗

PubMed2000

Effects of tooth-whitening gels on enamel and dentin ultrastructure--a confocal laser scanning microscopy pilot study.

Confocal laser scanning microscopy (CLSM) in reflection mode provides a useful means for nondestructive microscopic examination of the ultrastructural characteristics of hard tissues, including enamel and dentin. In this study, CLSM was used to examine the effects of in vitro bleaching on enamel and dentin. The crowns of extracted human third molars were sectioned below the occlusal fissure, revealing subsurface dentin and the outer surface ring of enamel. Specimens were polished with 1,200-grit alumina followed by fine polish lapidary film, and cut into four equal sections per tooth, allowing each tooth to serve as internal control. Sections were mounted in acrylate for handling and were bleached for 0, 15, and 30 hours in 0.25 g of commercial Opalescence whitening gel (10% carbamide peroxide), the 5.3% hydrogen peroxide gel used in Crest Whitestrips, or 5% HClO4 solution. Blank glycerin served as a control treatment. In vitro whitening was confirmed by colorimeter readings of delta b and delta L with a PR 650 spectrophotometer/colorimeter. Treated teeth were examined with CLSM comparing enamel surface, dentoenamel junction (DEJ), and dentin at approximately 5 microns subsurface to the polished surfaces under an oil immersion objective. A single sample from each treatment (30-hour whitening) was also examined by environmental variable pressure scanning electron microscopy (VP-SEM). Internal comparison of glycerin (no whitening) controls (0-, 15-, and 30-hour exposures) revealed reproducible ultrastructure, facilitating treatment comparisons. Whitened teeth revealed no significant micromorphological changes associated with the whitening process in subsurface enamel, DEJ, and dentin areas. The direct treatment of cross sections permitted simple access of all areas to whitening gel, thereby eliminating the possibility of diffusion limitation of the gel in producing artifacts. VP-SEM observations similarly showed no significant changes in the surfaces after treatment.

Carbamide Peroxide↗

PubMed2002

Effect of cyclical lateral forces on microleakage in cervical resin composite restorations.

OBJECTIVE: The aim of this study was to assess the effect on microleakage of cyclic lateral fatigue forces in different types of cervical resin composite restorations. METHOD AND MATERIALS: V-notch cavities were prepared at the cementoenamel junction in 60 extracted human premolars and restored with a bonding system along with one of the following resin composites: hybrid resin composite, microfilled resin composite, and flowable resin composite (20 each). Ten specimens from each group of 20 were subjected to 8,400 cycles of lateral fatigue forces (44 N) at the occlusal half of the clinical crown in a machine specifically developed for this purpose. The other 10 specimens of each group served as controls, representing the microleakage that occurred without lateral fatigue forces. All specimens were stained with a 50% silver nitrate solution and sectioned sagittally. A scoring system of 0 to 6 was used to record the amount of die penetration along the restoration-tooth interface. RESULTS: There was leakage in both the fatigued specimens and the nonfatigued control specimens. There were significant differences in the mean values of microleakage for the restorative materials studied. In the nonfatigued groups, hybrid resin specimens exhibited significantly more microleakage at the dentin-resin interface than did microfilled or flowable resin specimens. In the fatigued groups, hybrid resin specimens exhibited significantly more leakage at the dentin-resin interface than did microfilled resin specimens. CONCLUSION: The least elastic resin composite tested, the hybrid material, generally showed the most leakage. This suggests that the elasticity of these resin composite restorative materials may be a factor in the amount of microleakage in cervical restorations.

Barium Compounds↗

PubMed2001

Effect of dentin adhesives on the enamel-dentin/composite interfacial microleakage.

PURPOSE: To evaluate the microleakage at the enamel-dentin resin-based composite (RBC) interface of 4 dentin bonding systems (DBS). MATERIALS AND METHODS: Standardized kidney-shaped Class V cavities were prepared on the buccal and lingual surfaces at the cemento-enamel junction of 90 extracted human teeth and restored with a microhybrid RBC (Filtek P60) following application of either Excite (EXC), a single component adhesive; Prompt L Pop (PLP), a self-etching priming bonding adhesive; Clearfil SE Bond (SEB), a self-etching adhesive; or OptiBond Solo (OPS), a single component adhesive. The teeth were thermocycled, immersed in a dye solution and sectioned. The enamel failures and the occlusal and cervical dentin microleakages were measured. RESULTS: Significant differences were evident between the self-etching adhesives and the adhesives using phosphoric acid (P 0.05) for the enamel. The occlusal dentin microleakage was similar for the four DBS. PLP presented the worst values at the cervical dentin margin compared to the three other DBS. Significant differences were noted between PLP and EXC and OPS, which performed better.

Acid Etching, Dental↗

PubMed2001

Treatment of cervical dentin hypersensitivity with resin adhesives: 4-week evaluation.

PURPOSE: To evaluate the effectiveness of a dentin bonding agent containing HEMA compared to a resin emulsion in the reduction of cervical dentin hypersensitivity (CDH). MATERIALS AND METHODS: The study was a randomized-within-subject, double blind design. Twenty patients who were suffering from CDH from at least two teeth (canines and/or premolars) were enrolled. The subjective perceptions of pain in response to tactile, air blasts and cold ethyl chloride stimuli were evaluated using a visual analog scale (VAS) at baseline and 10 minutes, 1 week and 4 weeks after the treatments. Scotchbond 1 (a dentin bonding agent similar to Single Bond in the USA) and MS Coat (a resin emulsion), both applied according to the manufacturers' directions, were selected for the study. RESULTS: Multiple regression ANOVA for repeated measures showed that both treatments significantly reduced the CDS with respect the baseline values after just 10 minutes. There were no significant differences between the ability of the two treatments to reduce CDH for each of the three evaluation stimuli or for subjective evaluation.

Adult↗

PubMed2001

Comparison of the safety and efficacy of an oscillating/rotating battery-powered toothbrush and a standard manual toothbrush.

PURPOSE: To compare the cleaning efficacy of a battery-powered toothbrush with an oscillating/rotating action (Dr. Best Powerclean) and a standard flat-trimmed manual toothbrush (Elmex super 39) in a single-blind, cross-over clinical study. MATERIALS AND METHODS: 78 healthy subjects took part in the study. Subjects were asked to abstain from all oral hygiene procedures for 48 hours, after which hard and soft oral tissues were examined. Plaque was then scored using the Turesky modification of the Quigley-Hein Index, and subjects were instructed to brush their teeth for a total time of 1 minute with either one or the other brush, according to a predetermined randomization schedule. Immediately after brushing, plaque was scored again and hard and soft tissues were re-examined. All plaque scoring was carried out by the same investigator who was blind with respect to the brushes used. Subjects were instructed to continue with their usual oral care routine throughout the study period. They were scheduled to return after 12-14 days, having again abstained from all oral hygiene for 48 hours prior to the visit, in order to repeat the evaluation sequence but brushing with the alternative brush. Prior to analysis of the results, data from the two phases of the study were combined. RESULTS: Both toothbrushes were found to be safe as used in the study. Using the non-parametric Wilcoxon test for paired samples, whole mouth plaque scores were found to be reduced significantly from 2.04 +/- 0.60 to 1.57 +/- 0.51 by the Powerclean toothbrush (P < 0.001), and from 1.99 +/- 0.65 to 1.27 +/- 0.52 by the manual toothbrush (P < 0.001). At approximal surfaces, the plaque scores were also significantly reduced from 2.14 +/- 0.0.59 to 1.69 +/- 0.50 for the Powerclean (P < 0.001), and from 2.08 +/- 0.64 to 1.40 +/- 0.57 for the manual toothbrush (P < 0.001). A comparison of the two brushes revealed that the manual toothbrush removed significantly more plaque than the Powerclean, both for the whole mouth and approximal surfaces (P < 0.001). The Powerclean reduced whole mouth plaque by 23.2 +/- 11.5% compared to 37.8 +/- 14.0% for the manual toothbrush and approximal plaque by 20.9 +/- 10.6% and 34.9 +/- 14.0%, respectively. It is concluded that the Dr. Best Powerclean toothbrush is not as effective as a standard flat-trimmed manual toothbrush.

Adolescent↗

PubMedDate not supplied

Effect of four intermediate layer treatments on microleakage of Class II composite restorations.

This in vitro study examines the marginal sealing ability of four different intermediate materials applied before placement of a condensable composite. Class II preparations were made with gingival margins placed 1.0 mm apical to the cementoenamel junction of 60 extracted teeth, randomly assigned to five groups of 12. Following restoration, teeth were thermocycled, soaked in 0.5% basic fuchsin, and sectioned longitudinally. The resin-modified glass ionomer cement demonstrated significantly less microleakage than the use of a dentin bonding agent alone or in combination with flowable composite, flowable compomer, or autoploymerizing composite (p < 0.05, Dunn's test). This study supports the use of the glass ionomer open sandwich technique in deep Class II direct composite restorations.

Compomers↗