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PubMed2000

Fluoride release from light-curing restorative materials.

PURPOSE: To measure the in vitro fluoride release from three polyacid-modified resin-based composites (Dyract AP, Compoglass F, F2000) and one resin-modified glass-ionomer cement (Vitremer VLC) for 28 days in two different buffer solutions. MATERIAL AND METHODS: 30 cylindrical specimens of each material were prepared. Subsequently, 15 samples of each material were stored in neutral (pH 6.8) and acidic (pH 4.0) buffer solution (5 mL), respectively. After 4, 8, 12 hrs and 1, 2, 4, 8, 14 days, respectively, the samples were transferred into new solutions. The fluoride content was determined with a fluoride sensitive electrode. Data were analyzed with ANOVA, followed by closed-test-procedure based on Kruskal-Wallis. RESULTS: Compared to the neutral solution, all materials showed a significantly higher release of fluoride in acidic environment within the 28-day period (P < 0.001, ANOVA). In acidic buffer solution Vitremer VLC and Compoglass F showed a significantly higher fluoride release than F2000 and Dyract AP (P < 0.001, closed-test-procedure). In neutral solution Dyract AP showed the significantly lowest release (P < 0.001, closed-test-procedure). Fluoride release from the materials tested is higher in an acidic environment than in a neutral environment.

Analysis of Variance↗
PubMed2000

Stress reduction in resin-based composites cured with a two-step light-curing unit.

PURPOSE: To examine the stress reduction of different resin-based composites, cured with a two-step polymerization unit (Elipar Highlight) by means of a photoelastic investigation. MATERIALS AND METHODS: For each material (Pertac II, Tetric Ceram, Charisma F, Solitaire, Dyract, Dyract AP, Definite), a minimum of 10 resin samples, embedded in acrylic-glass plates, were polymerized using a standard polymerization process of 700 mW/cm for 40 s. Another 10 samples were polymerized with a light output of 150 mW/cm2 for 10 s and then with a light output of 700 mW/cm2 for 30 s. RESULTS: For Pertac II the reduction of polymerization stress in the two-step-mode was 15.5%, for Tetric Ceram 14.5%, for Solitaire 8.1%, for Dyract AP 6.5% and for Definite 4.7%. These differences in polymerization stress between the standard and two-step-polymerization mode were statistically significant (P < 0.01, Wilcoxon test). No statistically significant differences in polymerization stress could be found for Charisma F and Dyract.

Bisphenol A-Glycidyl Methacrylate↗
PubMed2001

Porosity of resin cements and resin-modified glass-ionomers.

PURPOSE: To quantify the internal free surface in various resin cements and glass-ionomer-based materials. MATERIALS AND METHODS: Materials tested were Nexus fluid (NXF) and viscous (NXV), Vitremer (VTM), Fuji II LC (FII), Vitremer Luting Cement (VLC), Dyract (DYR) and Compoglass (COM). Samples (n=5) were made of each material between two microscopic glass slides under same weight. With a transmitted light microscopy, four zones of each sample were evaluated, finding the number of porosities per mm2 (NP), the average radius of porosities (RP), the ratio of total area of surface porosities (micron2) to area (mm2) of specimen surface (TA) and the ratio of total volume of porosities (micron2) to area (mm2) of material surface (VP). RESULTS: Median test was used. NP: NXV, NXF and DYR had smaller NP than VTM and FII and (likely) than VLC (P> 0.0000001). RP was smaller for DYR than for VLC and (likely) than for NXV (P= 0.00019). TA: NXV, NXF and DYR had smaller TA than VTM, FII and VLC (P< 0.0000001). VP: NXV and DYR had smaller VP than FII and (likely) than VTM and VLC (P< 0.0000001).

Chi-Square Distribution↗
PubMed2000

[A clinical evaluation of two new materials for restoration of dental wedge-shaped defects].

OBJECTIVE: To evaluate clinically two new materials (Dyract Cem and 3M-Vitremer) for restoration of dental wedge-shaped defects with modified USPHS evaluation criterion. METHODS: 317 teeth with wedge-shaped defects were restored by Dyract Cem and 192 teeth by 3M-Vitremer clinically. The 1 year and 2 year follow-up results were evaluated with modified USPHS evaluation criterion. RESULTS: 1 year successful rate was 91.17% in Dyract Cem group and 81.77% in 3M-Vitremer group, and 2 years successful rates were 88.64% and 80.21% separately. The differences of successful rates between the two groups are significant statistically, but there are no significant differences in main indexes except stain rate when analysed item by item with USPHS evaluation criterion. Successful rates were related with the abrasive degree of the restored teeth. CONCLUSIONS: Both Dyract Cem and 3M-Vitremer have high successful rates and a lot of advantages for restoration of dental wedge-shaped defects. The modified USPHS evaluation criterion is a valuable method for clinical evaluation.

Adult↗
PubMed2002

Dental treatment, dental fear and behaviour management problems in children with severe enamel hypomineralization of their permanent first molars.

OBJECTIVES: To assess the demand for restorative treatment, dental anxiety and dental behaviour management problems among children with severe hypomineralization of their first molars (MIH). DESIGN: Case control study. SAMPLE AND METHODS: Data were compiled from the dental records of 32 9-year-old children with severe enamel hypomineralization of their first molars and from 41 controls of the same age group concerning dental health, a number of restorative treatments, use of local anaesthesia and clinical behaviour management problems (BMP). A questionnaire containing specific questions on children's experiences of dental care and the Children's Fear Survey Schedule-Dental Subscale (CFSS-DS), was answered by the parents. RESULTS: The children in the study group had undergone dental treatment of their first molars nearly 10 times as often as the children in the control group. Repeated treatments of these teeth at brief intervals were common. The dental treatment was often undertaken without the use of local anaesthesia, and BMP, and dental fear and anxiety (DFA) were more common than in the controls. CONCLUSIONS: Children with severe enamel hypomineralization of their first molars had had to undergo a considerable amount of dental treatment. It is reasonable to assume that experiences of pain and discomfort on repeated occasions were related to the occurrence of BMP in patients with MIH. An early treatment planning and prognostication based on increased knowledge of hypomineralized first molars is desirable. Local anaesthesia and other pain-reducing techniques, e.g. sedation, should be used when treating these teeth. Extraction should be considered in cases of extensive disintegration of the crown, in cases of frequently repeated treatments or when pulpal symptoms are hard to cure.

Anesthesia, Dental↗
PubMed2001

[Polymerization shrinkage by 4 different types of dental materials].

Forces developing during polymerisation of dental resins cause tension in the material to increase, with possible subsequent distortion of the bond. This study was undertaken to determine and compare polymerisation shrinkage in four different light-cured dental resins. A modified dilatometer was used to determine volumetric changes during polymerisation in 60 seconds of Z250 and Filtec flow from 3 M, and DyractAP and Dyract from Dentsply. Statistical analysis revealed that Dyract Flow shrinks significantly more (P < 0.05) during polymerisation in the first, as well as the last 10 seconds when compared with the other three materials and Z250 significantly less. An increase in the amount of fillers in the composition of the material leads to a decrease in polymerisation shrinkage, while an increase in the monomer concentration gives rise to more shrinkage. Stress, that builds up during the polymerisation process, is reduced by the elasticity of the material. The shrinkage of the flowables is therefore counteracted by their reduced rigidity.

Aluminum Silicates↗
PubMed2002

Microleakage of a packable composite associated with different materials.

The aim of this in vitro study was to evaluate the extent of marginal leakage with class II composite resin restorations associated with different materials. Twenty extracted sound molars were disinfected and stored in 0.9% saline solution. Four standardized class II cavities were prepared in each tooth, with the gingival margin 1 mm below the cementum-enamel junction. The teeth were then randomly divided into five groups of 16 restorations each: 1) Prime & Bond NT + Surefil; 2) Prime & Bond NT + Dyract Flow + Surefil; 3) Prime & Bond NT + Flow-it + Surefil; 4) Prime & Bond NT + Dyract AP + Surefil; and 5) Fuji II LC + Prime & Bond NT + Surefil. After a storage time of seven days, the restorations were finished and polished. Then specimens were submitted to thermocycling (500 cycles, 5 degrees-55 degrees C, 15 s-dwell time) and immersed in 0.5% methylene blue solution for 24 hours. They were washed and vertically sliced through the middle of the restoration. Both surfaces were evaluated in the gingival margin and one score (0-3) was assigned under a stereomicroscope (40x magnification) by two examiners. The frequency of the scores was evaluated by Kruskal-Wallis and Mann-Whitney tests for pairwise comparisons. None of the associations prevented dye penetration. The statistical analysis showed similar dye penetration among groups 1, 2, 3 and 4 (p > 0.05). The results of penetration in group 5 were significantly lower compared to the other groups (p < 0.05). It was concluded that the use of Fuji II LC as a base material led to the best sealing of the gingival margins based upon the lowest degree of microleakage observed.

Coloring Agents↗
PubMed2002

Illustrating predictable anterior and posterior esthetic results: two case studies.

More natural-looking restorations are possible today because of advances in the quality of impression materials and the techniques used for tooth preparation and cementation. This article presents two cases that illustrate the use of a new generation of impression materials, bonded resin cement, and pressable porcelain to obtain the desired esthetic result.

Adult↗
PubMed1996

[Resin-modified glass-ionomers in dentistry].

The resin-modified glass-ionomers contain the essential components of both a conventional glass-ionomer and a visible light-cured resin. They have several advantages like longer working time, shorter setting time, bonding to tooth structure, fluoride-release, better aesthetics than conventional glass-ionomers and ease in use. As disadvantages can be mentioned the polymerisation shrinkage, trapping of air-bubbles, difficulties in colour choice and contouring. A physical and mechanical characterisation was necessary to define the possibilities and limits of these materials. It can be stated that the strength and aesthetic appearance of resin-modified glass-ionomers are less than that of composites, but better than that of conventional glass-ionomers. Clinically, this is expressed in a rough and dull surface compared to a composite restoration. They are not indicated in stress bearing areas. Consequently, they are mainly indicated in cervical class V-restorations in the postcanine region, and probably restorations in pedodontics, geriatric dentistry and for patients with a high caries activity.

Compomers↗
PubMedDate not supplied

Effects of in-office tooth whiteners on hardness of tooth-colored restoratives.

This study investigated the effects of in-office tooth whiteners on the hardness of hybrid (Spectrum TPH), polyacid-modified (Dyract AP), PRG (Reactmer) composites and a resin-modified glass ionomer cement (Fuji II LC). Twenty-seven specimens of each material were fabricated, randomly divided into three groups of nine and treated as follows--Group 1: stored in distilled water at 37 degrees C for three weeks (control); Group 2: treated with carbamide peroxide (Opalescence Quick) for 30 minutes/week for three weeks; Group 3: treated with 35% hydrogen peroxide power bleach (Opalescence Xtra) for 30 minutes/week for three weeks. For Groups 2 and 3, specimens were stored in distilled water at 37 degrees C during the hiatus periods. The treated specimens were subsequently subjected to microhardness testing (load = 500gf; dwell time = 15 seconds). Results were analyzed using ANOVA/Scheffe's test (p<0.05). For all treatment groups, Spectrum was significantly harder than the other materials and Reactmer was significantly harder than Dyract and Fuji II LC. The effects of in-office tooth whiteners on microhardness were material-dependent. No significant difference in hardness was observed between treatment groups for Dyract and Reactmer. For Spectrum and Fuji II LC, specimens treated with Opalescence Quick were significantly harder than those treated with Opalescence Xtra. No significant difference in hardness was observed between the control and bleached groups for all materials. The hardness of resin-modified glass-ionomer cements, hybrid, polyacid-modified and PRG composites is therefore not significantly affected by the use of 35% carbamide peroxide and 35% hydrogen peroxide in-office tooth whiteners.

Analysis of Variance↗
PubMed2001

Radiopacity of esthetic restorative materials compared with human tooth structure.

PURPOSE: To compare the radiopacity of 13 restorative materials, (a conventional glass-ionomer cement, three resin-modified glass-ionomer cements, six polyacid-modified resin-based composites, and three resin-based composites) to sound tooth structure. MATERIALS AND METHODS: 315 specimens were made of the restorative materials (n = 21), of 2 mm height and 4.1 mm diameter. Radiographs were taken of the specimens, together with the tooth structure sample and an aluminum step wedge. The radiopacity values of each specimen were taken using a transmission densitometer. RESULTS: ANOVA and Tukey's test (95% level of confidence) revealed that, except for a resin-based composite, a polyacid-modified resin-based composite, a resin-modified glass-ionomer cement and the conventional glass-ionomer cement, all the evaluated restorative materials were more radiopaque than the tooth structure.

Absorptiometry, Photon↗
PubMedDate not supplied

Microleakage of two polyacid-modified resin composites under different conditioning methods in primary teeth.

This study evaluated the effect of different conditioning methods on micro-leakage in primary teeth. Fifty-one cervical cavities were prepared on the twenty-six extracted primary molars and divided randomly into five groups. In Group I and IV phosphoric acid, in group 11 non-rinse conditioner (NRC) was applied. In group III and V no pretreatment was used. Groups I-III were restored with Prime & Bond NT and Dyract AP and Group IV-V restored with Syntac SC and Compoglass F. The restored teeth were stored for 24 hours in distilled water at 37 degrees C, immersed in 0.5 percent basic fuchsin for 24 hours. Dye penetration was determined using a stereomicroscope. The results revealed that although enamel microleakage was not affected by the conditioning method used in both restorative materials, pretreating the cavity with phosphoric acid had a positive effect on reducing the dentin microleakage compared with conditioning by NRC.

Acid Etching, Dental↗
PubMed2002

Artificial formed caries-like lesions around esthetic restorative materials.

Dental restorations fail for a variety of reasons. Secondary caries is one of the primary causes of failure of dental restorations. One method for reducing frequency and severity of this problem is the use of fluoride containing restorative materials. The ability of a material to inhibit secondary caries formation is an important clinical therapeutic property. This investigation assessed the capacity of esthetic restorative materials to resist caries in vitro. Class V cavities were prepared in buccal and lingual surfaces of 50 extracted sound third molars. The occlusal and gingival cavosurface margin of each preparation was on enamel surface. The five materials were used: Conventional glass ionomer cement Ceramfil beta (PSP), two polyacid modified resin composites Compoglass (Vivadent) and Dyract (Dentsply/DeTrey), non fluoride releasing composite resin Valux Plus (3M) and fluoride releasing composite resin Tetric (Vivadent). After 10 weeks in an acid gel for caries-like lesion formation, the teeth were sectioned occluso-gingivally through the middle of the restorations and examined by polarized light microscopy, while immersed in water. The statistical analysis of the results showed that secondary caries initiation and progression might be reduced significantly when fluoride-containing materials were placed. The conventional glass ionomer cement (Ceramfil beta) provided the highest protection against caries attack and the non-fluoride releasing composite resin (Valux Plus) restoration provided the least (p<0.05).

Acids↗
PubMedDate not supplied

Clinical evaluation of a polyacid-modified resin composite (Dyract) in class III cavities: three-year results.

This study evaluated the three-year clinical performance of a polyacid-modified resin composite material, Dyract (DeTrey/Dentsply, Konstanz, Germany), in Class III cavities. Sixty-two Class III cavities in 30 patients were restored with Dyract. Restorations were clinically evaluated at baseline, one-, two- and three-year recalls according to the modified Ryge criteria by two experienced, calibrated examiners. After three years, the retention rate was 96.7%. At the one-year interval, one restoration had to be replaced due to sensitivity. At the two-year recall, one restoration, with a caries lesion adjacent to its margin, was clinically unacceptable and had to be replaced. Except for these two restorations, all other restorations were clinically acceptable in regard to color match, marginal discoloration, wear or loss of anatomical form, caries, marginal adaptation and surface texture after three years. At the end of three years, marginal discoloration was statistically significant (p=0.017) but did not require replacement of any of the restorations. Dyract exhibited significant marginal discoloration after three-year clinical performance in Class III cavities.

Adolescent↗
PubMed2001

Bilateral talon cusp: case report.

Talon cusp is an uncommon condition often present in the maxillary incisors and mandibular premolars. Morphologically, this anomaly has a well-delineated cusp that extends at least half the distance from the cementoenamel junction or cingulum area to the incisal edge. The alteration can cause clinical problems such as caries or occlusal interference. Management of the talon cusp varies according to the circumstances of the individual case and should be as conservative as possible. Presented is a case of bilateral bifid talon cusp in maxillary central incisors that was successfully managed with conservative therapy.

Acid Etching, Dental↗
PubMedDate not supplied

The effect of rebonding on microleakage of class V aesthetic restorations.

This in vitro study evaluated the effect of rebonding on microleakage of a resin composite, a condensable resin and two polyacid-modified resin composite restorations. Standardized cylindrical Class V dentin cavities were prepared on the buccal root surfaces of 240 extracted bovine incisive teeth. The prepared teeth were randomly assigned to four groups of 60 teeth and restored with the following restorative systems: I--(ZS) Z100/Scotchbond Multi-Purpose Plus; II--(SS) Solitaire/Solid Bond; III--(FS) Freedom/Stae; IV--(FSB) F200/Single Bond. Thirty teeth of each group were rebonded with a low-viscosity resin (Fortify/BISCO), according to the manufacturer's instructions. The remaining teeth received no treatment. All teeth were thermocycled for 5,000 cycles and brushed by hand three times a day for 10 days using a toothbrush and a slurry of dentifrice and water. Specimens were stained in a 2% methylene blue solution and longitudinally sectioned with diamond disks. Microleakage was scored on a scale of 0 to 3. The Kruskal-Wallis test showed statistically significant differences among the groups (h=156.54; alpha<0.05). Pairwise comparison by means of the least significant difference showed that (SS) and (FS) with or without rebonding were not statistically different from each other. These groups showed the highest microleakage differences from (ZS) and (FSB) with or without rebonding. (ZS) with rebonding showed the lowest microleakage that was not statistically different from (ZS) without rebonding and (FSB) with rebonding.

Animals↗
PubMedDate not supplied

Two-year clinical evaluation of four polyacid-modified resin composites and a resin-modified glass-ionomer cement in Class V lesions.

OBJECTIVE: The aim of the study was to compare the clinical performances of four polyacid-modified resin composites (F2000, Dyract AP, Compoglass F, and Elan) and one resin-modified glass-ionomer cement (Vitremer) in Class V abrasion/erosion lesions. METHOD AND MATERIALS: Twenty restorations of each of the five restorative materials were placed in noncarious cervical abrasion/erosion lesions by one dentist. No cavity preparation was attempted. All teeth were isolated with cotton rolls and gingival retraction cord. The materials were manipulated according to the manufacturer's instructions and placed with the help of cervical matrixes. Restorations were finished and polished immediately after the placement. Evaluations were performed at baseline and 6 months, 1 year, and 2 years after placement for retention, color match, cavo-surface marginal discoloration, anatomic form, marginal adaptation, secondary caries, and postoperative sensitivity. RESULTS: Retention levels at 2 years were 90% for F2000, 90% for Dyract AP, 89% for Compoglass F, 84% for Elan, and 95% for the Vitremer restorations. No statistically significant differences were found among the materials after 2 years for any evaluation category. CONCLUSION: Polyacid-modified resin composite and resin-modified glass-ionomer cement restorations showed acceptable clinical performance after 2 years.

Adult↗