The epidemiology of Neisseria gonorrhoeae isolates in Greenland 1979-1990: the emergence, spread and disappearance of non-PPNG strains carrying the conjugative 38.9 kb plasmid

The aim of this study was to compare the clinical performance of an amalgam, a glass polyalkenoate (ionomer) cerment material and a resin-based composite material used in small Class II cavities in permanent teeth. All restorations were inserted under rubber dam. They were examined yearly for 3 years. One clinician continued the study up to 5 years. The clinical examination focused on two criteria: clinically acceptable and failure. In addition, impressions were taken of the prepared cavities immediately before restoration and at each clinical examination using an elastomeric material. The study comprised 274 Class II restorations (88 amalgams, 95 cerments and 91 resin composites) placed in 142 adolescent patients. One hundred and sixty-seven restorations were in molar and 107 in premolar teeth. Patient dropout after 5 years resulted in the loss of 161 restorations, evenly distributed for restorative material and type of tooth involved. Four amalgam restorations, 22 glass ionomer cerment and nine resin composite restorations failed. The glass ionomer cerment and amalgam restorations failed primarily due to bulk fractures, while the resin composite restorations failed due to secondary caries and bulk fractures.     

Polymerisation shrinkage around composite resin restorations--an in vitro study

The aim of this study was to determine the degree of penetration of a fluorescent adhesive at the margins of 3 brands of posterior composite resin restorative materials. Seventy-eight extracted human premolar teeth were used. Class II cavities were prepared on both approximal surfaces of each tooth in such a manner that the gingival wall was situated apical to the amelo-cemental junction. The enamel of the cavity walls was bevelled, etched and treated with the enamel bonding agent recommended by the manufacturer. The 3 brands of composite resin used were: Fulfil, Estilux Posterior and P 50. The teeth were divided at random into 3 groups of 26 premolars each. The mesial and distal cavities of each tooth in the group were filled with the same brand. The resin was inserted in two increments in both the mesial and distal cavities and polymerised. The margins of one restoration in each tooth was coated with fluorescent adhesive and cured. All the restored teeth were embedded in clear epoxy resin and then sectioned. The mounted sections were examined at 100X magnification with fluorescent light. The polymerisation contraction gap at different areas of the tooth/restoration interface and the degree of penetration of the fluorescent adhesive into the gap was determined. The fluorescent adhesive penetrated the contraction gaps in all 3 posterior restorative materials to varying degrees. The defects observed were similar in all 3 brands and the differences in degree of penetration were not statistically significant (p > 0.05).     

Metallothionein content increased in the liver of mice exposed to magnetic fields

OBJECTIVES: The aim of this investigation was to evaluate the significance of selected surface texture parameters used to describe and quantify the effect of tooth brushing with various "tooth whitening" dentifrices on a resin composite surface in vitro. METHODS: Specimens of a microfil resin composite were brushed with selected dentifrices. Surface texture profiles were acquired and analyzed both pre- and post-brushing using a contact diamond stylus. The selected parameters chosen to describe the surface texture were Ra, Rz, Rpm and the Rpm:Rz ratio. Differences between toothpastes were assessed using an ANOVA and a multiple comparisons test, the Student Newman-Keuls procedure. P and t values were calculated to determine if any of the surface roughness parameters were significantly changed by brushing. RESULTS: The results indicate that there were significant changes in the surface texture of the resin composite following tooth brushing with the selected dentifrices. For example, the use of Clinomyn significantly increased the surface roughness of the resin composite, as measured by the Rz parameter, from 2.19 +/- 1.67 microns to 10.02 +/- 2.57 microns (p < 0.05). In addition, the surface texture parameters chosen to describe the properties of the surface should reflect a knowledge of profile shape such as Rpm:Rz ratio, and care should be taken if measurements of surface texture of dental restorative materials are to be used as predictors of clinical performance. SIGNIFICANCE: All the toothpastes chosen for this investigation left a surface on the resin composite which may be prone to crack propagation during "vertical barrelling" movements generated during mastication. However, this may be more of a function of the rigidity of the restorative material rather than the surface left after tooth brushing.     

The direct/indirect composite resin veneers: a case report

Veneer restorations are well suited for conservative and aesthetic improvement of the anterior dentition. Laboratory fabricated porcelain and composite resin veneers present optimal aesthetics and durability. Although there are disadvantages associated with direct bonding, it provides control of color and contour for the operator, particularly in the case of a single anterior central incisor. Direct/indirect composite resin veneers utilize the advantages of both direct and indirect techniques in reconstruction of restorations with improved physical properties. The learning objective of this article is to review the available composite resins, opaquers, and tints, and present a step-by-step protocol for predictable restoration of discolored anterior dentition with direct/indirect heat-treated composite resin veneers in a single appointment. Patient evaluation, preoperative aesthetic considerations, selection of the restorative composite resins, and the clinical procedure are discussed.     

Post and core reconstruction for fixed prosthodontic restoration

If the previous restorative therapy or dental caries has resulted in substantial loss of tooth structure, the abutment teeth for fixed prosthodontic restorations require a core reconstruction or a post and core. Small dentin defects can be restored with bonded cores; more extensive dentin defects that are often accompanied by previous endodontic treatment generally require additional support for the core material. A direct procedure with a bonded post is a viable treatment method. The decision to use either light-conducting all-ceramic zirconium or titanium as a post material depends on the aesthetic requirements present. The indications for a cast post and core as an indirect procedure for prosthodontic reconstructions appear to be decreasing. The learning objective of this article is to review the past and current post and core materials and techniques. Indications for core reconstruction with vital teeth and posts and cores for pulpless teeth are discussed.     

Low-frequency ultrasound treatment of chronic venous leg ulcers in an outpatient therapy

An in vitro dye leakage study was performed to compare the sealing ability of glass ionomer, composite resin and glass ionomer/resin cement when used as restorative materials for G.V. Black class V cavities. In this research, standard Class V cavities were prepared in sound premolar teeth extracted for orthodontic reasons. The cavities were randomly divided into 3 groups. After filling the cavities with glass ionomer cement, composite resin and light curing glass ionomer/resin cement, the specimens were immersed in silver nitrate solution. Marginal microleakage at the interface between the cavity wall and restoration was evaluated. The results were analyzed by using Kruskal-Wallis and Mann Whitney U tests. Result of this in vitro study indicate that composite resin and glass ionomer/resin cement provide a better seal than glass ionomer cement.     

The effect of core translucency on the aesthetics of all-ceramic restorations

Recent advances in ceramic technology have revolutionized aesthetic dentistry. When treating a single anterior tooth in need of a full-coverage restoration, a multitude of options in restorative materials and techniques is available to the clinician. The learning objective of this article is to present and evaluate a selection of all-ceramic dental materials currently available for aesthetic full-coverage crown restorations. When selecting an all-ceramic system, there are several major factors to consider, including the inherent translucency of the ceramic material and of the adjacent dentition, the color of the prepared tooth, and the forces anticipated in that region. Preparation and restoration of discolored and nondiscolored tooth structure are reviewed. The techniques presented can be utilized to obtain predictable results in the anterior region for aesthetic all-ceramic full-coverage restorations.     

Ten-year longitudinal clinical evaluation of a visible light cured posterior composite resin

Using modified USPHS criteria, we evaluated annually for ten years 91 cases restored with visible light cured posterior composite resin LFP (Base resin: UDMA; filler: micro crushed type, alumino-silicate, barium glass and silica, 85 wt%, 74 vol%). The 91 cases restored with LFP decreased to 68 in ten years. Of the 23 cases that were lost, one resulted from a pulpal reaction immediately following restoration, four were extracted owing to periodontal disease or extrusion of third molars, two became abutments owing to loss of an adjacent tooth, eight had recurrent caries, and eight were lost owing to caries on a surface having no relationship to the composite resin restoration. Because we observed comparatively little wear, good marginal adaptability, and no discoloration, we concluded that the ten-year clinical success of LFP was on the whole very good, and that this resin has adequate clinical merit as a restorative material for posterior teeth when restricted to restorations covering comparatively small areas.     

Wear resistance of four luting agents as a function of marginal gap distance, cement type, and restorative material

This study investigated the effect of marginal gap width, luting cement, and restorative material on the wear resistance of the luting cement in areas where no occlusal contact is present. Three types of resin luting cement and one resin-modified glass-ionomer cement were used with two inlay systems, a resin composite, and an all-ceramic system. Bovine enamel represented tooth structure. Toothbrush abrasion was the wear modality. Three predetermined gap widths were selected: 240 +/- 30 microns, 150 +/- 30 microns, and 60 +/- 30 microns. All specimens were thermocycled. Regardless of the luting cement or the restorative material, there was a significant difference (P < 0.05) in wear resistance of the cement among the three gap distances at both the enamel and restoration interface. Vertical wear of the luting cement at the enamel interface increased linearly with marginal gap distance when all four cements were considered together (r2 > 0.51), regardless of type of restorative material used. The resin-modified glass-ionomer cement showed the least amount of wear for all variables considered. Significant differences in wear were found between the four luting cements at wide gap distances (240 microns) at the enamel interface, regardless of type of restorative material used. No significant differences were found between the two restorative materials at the enamel interface at the three gap distances.     

Dexamethasone enhances macrophage colony stimulating factor- and granulocyte macrophage colony stimulating factor-stimulated proliferation of bone marrow-derived macrophages

The authors describe a study in which they placed 126 Class V composite resin restorations without mechanical retention, divided into three groups of 42, in 23 patients. They followed the performance of the restorations over a three-year period. For all three groups, restorations were placed using All-Bond 2 dental adhesive and Z100 composite resin; A.R.T. Bond and Brilliant Dentin composite; and Prisma Universal Bond 3 and Variglass VLC polyacid-modified composite resin. The authors evaluated retention as well as color stability, wear resistance, sensitivity, sulcular depth, loss of attachment, bleeding on probing and crevicular fluid flow. Based on their results, the authors propose that restoration of Class V lesions without using mechanical retention could be expected to succeed in seven of 10 restorations over a three-year period using these restorative systems.     

Indirect composite restorations in the anterior region: a predictable technique for complex cases

The indirect composite inlay technique demonstrates excellent aesthetic results in the posterior regions, achieved by reproducing the shape, color, and contour of the natural tooth on a cast model rather than using the free-hand composite restorative modality. The utilization of the indirect technique can be adapted for the anterior regions as well, and it offers a valid treatment alternative that is predictable with optimal restorative results. The evaluation, planning, and accuracy of implementation of the various phases of this methodology allow a more precise achievement of the result; any potential error in the restoration can be corrected prior to final cementation. This technique increases the quality of composite restorations that have always been considered unpredictable and extensively dependent upon the skills of the operator. The learning objective of this article is to familiarize the reader with the clinical and laboratory phases of this indirect treatment modality of the anterior dentition.     

Posterior composite resin restorations: operative innovations

The adhesive revolution is alleviating reservations regarding posterior composite resin restorations, established by past experience with outdated materials and techniques. Improved materials, instrumentation, and placement techniques have enhanced the performance of current formulations of posterior composite resins over their predecessors. However, it is a clinician's operative skill that ultimately determines the quality of a restorative option. The learning objective of this article is to share the author's experience in attaining adhesive excellence with posterior tooth-colored restorations as well as aesthetic anatomic form, minimal postoperative sensitivity, and a bond which can weather the true test of success-durability. Optimal applications, dental dam requirement, importance of the first increment of composite resin, restitution of occlusal morphology, and the clinical application are discussed.     

Enamel pretreatment with sodium hypochlorite to enhance bonding in hypocalcified amelogenesis imperfecta: case report and SEM analysis

Bonding composite resin to enamel of teeth affected by amelogenesis imperfecta (AI) is often problematic, especially in cases with poorly mineralized, friable enamel. Difficulty in bonding hypomineralized enamel can significantly limit the restorative and orthodontic treatment options for AI patients. In this report, we document a novel approach to bonding AI enamel by pretreating the tooth surface with 5% sodium hypochlorite (NaOCl), resulting in improved bonding of an orthodontic bracket to a previously impacted maxillary canine.     

The aesthetic composite bridge

New developments are constantly introduced in the search for the optimal treatment modality to restore a single anterior tooth. The patient attention has shifted to aesthetics of the restoration, biocompatibility of the dental materials utilized, conservative preparation of the teeth to be restored, and the retention of intact adjacent dentition. The learning objective of this article is to review the methods currently utilized and to present a recently introduced treatment modality--the two-component bridge, which combines the strength and resiliency of composite resin with the aesthetic advantages of porcelain. The technology of the material is reviewed, the predominantly lingual tooth preparation procedures are outlined, and the bridge try-in is described. The advantages of the two-component bridge are presented along with the contraindications and suggestions of careful case selection. Three cases with congenitally missing maxillary lateral incisors in youthful patients are presented to supplement the theoretical outline and to describe and illustrate the clinical procedure.     

The status of indirect restorative dental materials

The ideal restorative material should enable restoration of teeth that have either suffered trauma or have been prepared during the removal of caries to their original function and appearance. At the same time a seal should develop between the material and the tooth to prevent bacteria-laden fluids from permeating the dentine and reaching the pulp. Few, if any, of the available materials fulfil these requirements. This, the second of a short series, considers the status of indirect restorative materials as the millennium approaches. In this review indirect restorative materials are regarded as those which call not only upon the dexterity and judgement of the dental practitioner, but also upon the skills of the dental technician and techniques of construction that are suitable for use only in a laboratory. Included in this group are the dental casting and bonding alloys, dental ceramics and those resin composites that are shaped, cured and finished in the laboratory.     

A procedure for preparing undecalcified and unembedded bone sections for light microscopy

Recently, new restoratives, such as resin-modified glass ionomer cements (RMGIC) and polyacid-modified resin composites (PMC) were introduced for class III and class V cavities. Both materials use simplified cavity conditioning methods. The well-established treatment of enamel with phosphoric acid has been replaced with treatment using weaker acids. The purpose of this study was to investigate in vivo the quality and durability of the marginal bond to enamel of these restorative system and compare it with a resin composite restorative, Seventeen patients received class III restorations of each of the three restoratives. At baseline and after 1 year replica impressions were made for investigation of the vestibular margins with the scanning electron microscope. Semi-quantitative analysis of the enamel-restorative interfaces was performed at x200 and x1000 magnifications. The three restorative systems showed good marginal adaptation and high percentages of the length of the margins investigated at baseline were gap-free (82%-92%). The resin composite showed significantly better adaptation than the other materials. The marginal quality decreased significantly after 1 year for the resin composite and the polyacid-modified resin composite. The RMGIC showed improved sealing after 1 year in vivo, probably due to continuing water uptake. The percentages of gap-free margins of the total marginal length observed at 1 year were 73%, 90%, and 84%, respectively, for the PMC, the RMGIC and the resin composite. The difference between the PMC and the RMGIC was significant. In conclusion, a good marginal quality was seen for all three restorative systems in class III cavities after a period of 1 year.     

Presurgical prosthetic management of the periodontal patient--a modern adhesive approach

The comprehensive management of the periodontal prosthetic patient requires that treatment be provided in a logical sequence; initial therapy, presurgical prosthetic management, surgical management of hard and soft tissue lesions, post-surgical prosthetics, followed by maintenance therapy. This article focuses on some of the most perplexing challenges encountered during the presurgical prosthetic management phase of periodontal diagnosis and therapy, including the stabilization of mobile teeth, the immediate replacement of teeth that require removal due to advanced attachment loss, and the correction of visual defects created by soft tissue loss. A number of creative treatment modalities are described that utilize silane-treated etched-glass fiber ropes and tapes (GlasSpan, GlasSpan, Inc.) for the internal reinforcement of periodontal splints and for the attachment of composite and natural tooth pontics as transitional tooth replacements. Gingival-colored composite (Gingiblend, Jeneric Pentron) and its importance as a diagnostic aid during the early stages of periodontal therapy and as an esthetic permanent restorative material are also examined.     

Intraoral repair of cosmetic restorations

The longevity of porcelain and composite resin restorations can often be prolonged by using sound principles, up-to-date materials, and judicious attention to repair when fracture problems arise. Careful case selection and correct usage of surface treatment agents, followed by the use of a quality bonding system and restorative materials, can result in a repair that exhibits excellent retention and natural color blending. This article outlines procedures and materials to repair both resin composite and porcelain intraorally.     

Artificial caries formation around fluoride-releasing restorations in roots

Secondary caries is one of the most important factors leading to replacement of dental restorations. This investigation assessed the capacity of fluoride-releasing restorative materials to resist caries in vitro when used in roots. Class 5 cavities were prepared in the buccal and lingual surfaces of 30 extracted premolars. The six materials used were: glass-ionomer cement (Fuji), glass-ionomer cement with silver particles added (Ketac-silver), fluoride-containing composite resin (Tetric), composite resin (Silux plus), fluoride-containing amalgam (Fluor-Alloy) and high-copper amalgam (Dispersalloy). After 5 weeks in an acid gel for caries-like lesion formation, the teeth were sectioned longitudinally and examined with polarized light. The results showed that repair with glass-ionomer materials of a carious lesion may be of great importance in the prevention of secondary caries around the restorations in roots.     

Primate pulpal response to ultraviolet light-polymerized direct-bonding material systems

The results of this study, plus those of a previous study, show that a layer of CaOH lining the floor of the tooth cavity will protect the dental pulp against toxic irritants inherent to an UV light-polymerized cavity liner and a UV light-polymerized composite restorative resin. This study also showed that a layer of CaOH lining the floor of the cavity will protect the dental pulp against acid irritants inherent in the enamel etching solution. It is recommended to restorative dentistry that all primary dentin within clinically accessible areas of the cavity preparation be covered with a layer of CaOH before the enamel is etched with the acid-conditioning solution. Precautionary protection of primary dentin in this manner affords a margin of safety should the conditioning solution inadvertently spill onto the primary dentin during the enamel-etching procedure. Second, if the conditioning solution does accidentally spill onto the previously placed protective layer of CaOH during the enamel-etching procedure, then it logically follows that this acid-contaminated layer of CaOH should be mechanically removed and a new layer of CaOH that completely lines at least the floor of the tooth cavity should be placed before the resins are applied.