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At least 199 records · Page 11Linked to original sources
PubMed2002

Complex single-tooth restorations.

There are many options for restoring the decimated dentition. [43] Excellent results can be obtained with many of the materials currently available. The restorative option will depend on the size and location of the lesion, adequate isolation for adhesive restorations, caries rate, the patient's age, the aesthetic needs of the patient, occlusal habits, maintenance of maximum tooth structure, the skill of the dentist, and the longevity desired for the restoration. Amalgam is a cost-effective material, and when used properly, it can provide many years of service. Aesthetic demands, the desire to strengthen teeth, [44] and concern about the safety of mercury in amalgam have increased the use of direct composites, ceramic material, and indirect composites. The main drawback with these materials, however, is their increased technique sensitivity and concerns about their longevity. Gold continues to be a cost-effective and predictable material if placed properly. Full-coverage gold or porcelain fused to metal provides long-term predictability but is more destructive and not as aesthetically appealing. The wide varieties of materials available provide both a challenge and an opportunity to place the most effective material for a particular patient. A thorough understanding of the available materials and their appropriate use is needed to achieve a long-lasting restoration that serves the patient's needs.

Acid Etching, Dental↗
PubMed1987

Contour of class V composite restorations.

For class V composite restorations, reproducing the natural contour of the tooth may best be attained with the use of a matrix. The matrix techniques that produced the best contours were the compound index with the plastic sheath or Mylar strip, and those among the worst used the composite instrument with and without alcohol.

Composite Resins↗
PubMed1997

Crown foundations with a custom matrix, composites, and reverse carving.

This article describes a restorative technique for the formation of composite cores for artificial crowns. The procedure uses a semirigid matrix with reverse carving to form the cores on substantially compromised teeth. The matrix allows the placement of the composite under pressure to reduce voids and gaps and permits completion of multiple cores simultaneously. Reverse carving enables development of a common axis for multiple cores. The dentist can perform the tooth preparation for the crown at the time of the core restoration. The effort commonly applied to developing tooth morphologic features in the core can be invested instead in the formation of the interim restoration. The remaining tooth structure, pin or post placement, and location of the finish line can be evaluated with the insight of a crown foundation and not merely as a traditional restoration.

Composite Resins↗
PubMed1998

Comparison of the new matrix system with traditional fixed prosthodontic impression procedures.

This article compares the methods and effectiveness of traditional fixed partial denture impression systems, which includes the matrix impression system, in relation to the registration of the finish lines and sulci of tooth preparations in the formation of a full arch impression. Concepts relating to custom trays, retraction, homeostasis, sulcular cleansing, sulcular flange registration, configuration and strength, viscosity of elastomeric impression materials, and delivering the impression material into the sulcus are reviewed. Several concepts are questioned and alternative procedures are proposed. Forces that impact the gingival tissues and determine the success of the impression are briefly described.

Dental Impression Materials↗
PubMed1998

The matrix impression system for fixed prosthodontics.

This article describes the instrumentation, materials, and clinical procedures for the matrix impression system. The matrix impression system uses a custom matrix to control the sulcular environment and to deliver impression material to the subgingival parts to be impressed. It describes the four types of forces involved in gingival displacement during impressions, effective delivery of impression material with simultaneous sulcular cleansing, and simplification of complex impressions with or without segmentation. The application of the matrix impression system is described for making routine impressions and for some atypical problems. The article also provides a detailed description of the formation and design of the matrix.

Dental Impression Materials↗
PubMed2001

Do condensable composites help to achieve better proximal contacts?

OBJECTIVES: Obtaining acceptable contact areas with adjacent teeth is a significant challenge when placing direct resin composite in Class II preparations. It was the purpose of this laboratory study to evaluate the influence of the type of resin composite ('packable' vs conventional) and of the matrix system on the quality of the proximal contact area in Class II composite restorations. METHODS: A standardized DO cavity was prepared in 170 frasaco teeth. Two operators each filled 85 teeth in the same frasaco model using four resin composites [Solitaire (S), Surefil (Su), P60, Z100], three matrix systems [Automatrix (A), Palodent (P), Lucifix matrix (L)] and one hand instrument specially designed to achieve better proximal contacts [Belvedere Composite Contact Former (B)]. The teeth were subdivided into 17 groups (Z100/1-A, Z100/1-P, Z100/1-L, S-A, S-P, S-L, Z100/1-A-B, Z100/1-L-B, Su-A, Su-P, Su-L, P60-A, P60-P, P60-L, Z100/2-A, Z100/2-P, Z100/2-L). Each operator made five fillings of each group. The quality of the proximal contacts was assessed by measuring the maximum mesio-distal (M-D) diameter of the restored teeth using a digital micrometer and the tightness of the proximal contact area using standardized metal blades. All data were analyzed using two-way ANOVA and Bonferroni/Dunn's test for multiple comparisons with a significance level of P<0.05. RESULTS: Regarding the matrix system, a significant larger M-D diameter and a stronger proximal contact area was achieved with the Palodent matrix system. The use of the Belvedere Composite Contact Former together with Lucifix matrix and Automatrix contributed to significantly stronger proximal contact areas. Concerning the type of resin composite, no significant differences were noted for both evaluation criteria when Palodent was used. Using Automatrix or Lucifix matrix, the more condensable resin composite P60 scored slightly better than Surefil and Z100. There was no operator effect. Both operators underwent a learning process. The longer they worked with a specific material/technique, the better proximal contacts they achieved. SIGNIFICANCE: The best proximal contact areas in Class II composite restorations were obtained using a sectional matrix system. The 'packability' of the resin composite did not help to achieve better proximal contacts.

Analysis of Variance↗
PubMed1997

Vasoactive intestinal peptide supports induced migration of human keratinocytes and their colonization of an artificial polyurethane matrix.

We investigated the effect of the neuropeptides vasoactive intestinal peptide (VIP), (D-Phe2)-VIP, (Lys-Pro-Arg-Tyr)-VIP and the VIP fragment (1-12) on induced migration and colonization in vitro. In confluent keratinocyte cultures "wounded" with a razor blade, the VIP-treated samples disclosed a more rapid migration from the wound margins into the wound bed, starting within the first 4 h. Almost 80% of the wounded area was covered within 24 h. In contrast, VIP-derivatives were not significantly different from controls, covering 10 to 18% of the wounded area (p < 0.02). Colonization has been assessed with an artificial non-toxic polyurethane matrix. In controls, we were able to observe migration of keratinocytes on the matrix within the first 24 h. The cells, however, were not able to migrate further and to survive. After 48 h, VIP-treated cultures showed a complete colonization of the matrix by keratinocytes vs. less than 10% of the total area in controls (p < 0.001). The induction of migration and of colonization was VIP-dose-dependent. The data indicate that induced migration is stimulated by VIP, when the N-terminal ending is intact, but loss of the C-terminus abrogates both migration and colonization. Our investigations have implications for wound healing but also for bioengineering of skin.

Cell Movement↗
PubMed2003

Cuspal movement and microleakage in premolar teeth restored with a packable composite cured in bulk or in increments.

INTRODUCTION: The aim of this study was to investigate the effect of two novel curing systems (a plasma arc light, and a 'turbo-boosted' conventional curing light) on cuspal movement and gingival microleakage of 'packable' resin-based composite (RBC) restorations placed in extracted maxillary premolar teeth. MATERIALS AND METHODS: Forty sound extracted upper premolar teeth were subjected to standardised preparation of a large mesio-occlusal-distal cavity before restoration with a RBC. Four curing regimens were used. Either the RBC was placed in bulk and light-cured in one increment using (a). the plasma arc light; (b). the 'turbo-boosted' curing light, or the RBC was placed in eight increments using (c). the plasma arc light; (d). the 'turbo-boosted' curing light. A deflection measuring gauge allowed a measurement of cuspal deflection at each stage of polymerisation. Restored teeth were thermocycled before immersion in a 0.2% basic fuchsin dye for 24 h. After sagittal sectioning of the restored teeth in a mesio-distal plane, the sectioned restorations were examined to assess cervical microleakage. RESULTS: Cuspal deflection measurements were significantly increased when the 'turbo-boosted' halogen curing light was compared with the plasma arc light. Total mean cuspal deflection measurements obtained with incremental cure were significantly increased compared with bulk cure for both light sources. Gingival microleakage for bulk restored teeth was significantly increased compared with teeth restored incrementally. Incremental restoration with the plasma arc light had significantly increased gingival microleakage compared with the 'turbo-boosted' halogen curing light. CONCLUSIONS: The packable composite tested could not be cured adequately to a depth of 5 mm with the plasma arc light within the specified irradiation time. Under the test conditions of the current investigation, bulk curing only appeared to be practical with the high intensity halogen light (40 s activation). Incremental build-up and polymerisation optimised marginal seal for the high intensity halogen light but led to greater cuspal deflection.

Bicuspid↗
PubMed1999

Marginal adaptation of direct composite and sandwich restorations in Class II cavities with cervical margins in dentine.

OBJECTIVES: The aim of this study was to evaluate the marginal adaptation of direct Class II sandwich restorations with resin-modified glass-ionomer cements and compomers in comparison to base and total bond restorations. For sandwich restorations with a triple cure resin-modified glass-ionomer cement the influence of different light curing techniques was also evaluated. METHODS: Large butt-joint class II cavities with cervical margins 1 mm below the cemento-enamel junction were cut into 120 extracted human molars. The cavities (15 groups, n = 8) were filled using a sandwich, base or total bond technique with materials from five different manufacturers. A three-sited light curing technique was used in 13 groups. For the material combination Vitremer/Z100 two additional groups with a different wand positioning and a metal matrix were evaluated. After water storage for 21 days and thermocycling (2000x, 5-55 degrees C), replicas were quantitatively analysed in the SEM. Statistical analysis was performed with the Kruskal-Wallis test and the Bonferroni test at p < 0.05. RESULTS: The marginal adaptation of vertical enamel margins was not dependent on the restorative technique. For margins in dentine, marginal adaptation was significantly better with the sandwich technique than with a base or total bond technique for all materials. There were no significant differences between the base and total bond technique. Overall, resin-modified glass-ionomer cements showed somewhat better results than compomers in sandwich restorations, though differences were not significant for some criteria. Vitremer/Z100 sandwich restorations applied with a metal matrix showed the highest mean percentage of excellent margins of all experimental groups. CONCLUSIONS: Both resin-modified glass-ionomer cements and compomers can improve the marginal quality when used in a sandwich technique. Further research is necessary to determine the ideal material combination for sandwich restorations.

Compomers↗
PubMed2002

Crowns and other extra-coronal restorations: cores for teeth with vital pulps.

Cores for teeth with vital pulps is the seventh in the series of crowns and other extra-coronal restorations. A core is defined as 'that part of a preparation for an indirect restoration consisting of restorative material'. This article questions the need for routine pin placement and addresses the following issues--removal of existing restorations, the need for a core, core materials, core retention, and problem solving.

Composite Resins↗
PubMed2002

Crowns and other extra-coronal restorations: provisional restorations.

The important role of provisional restorations is often overlooked. This may be because they are left until the end of an appointment when time for construction is short or because they generally do not need to last for long. However, not only can good provisional restorations help produce better final restorations, they can also save a lot of time and expense at subsequent appointments. In fact time spent in their construction will be more than repaid in time saved doing additional procedures, adjustments and remakes later on.

Acrylic Resins↗