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At least 433 records · Page 24Linked to original sources
PubMed1998

Development of gingivitis around aged restorations of resin-modified glass ionomer cement, polyacid-modified resin composite (compomer) and resin composite.

Resin-modified glass ionomer cements (RMGIC) and polyacid-modified resin composites (PMC, compomers) are two recently introduced material groups supposed to replace traditional cements in operative dentistry. The new restoratives release initially fluoride in different relatively high concentrations, which decrease gradually during the first weeks in vivo. Earlier studies showed a stronger subclinical inflammatory reaction around different conventional tooth colored restorative materials than around intact enamel. The aim of this study was to compare intra-individually the initiation of gingival inflammation around, aged RMGIC, PMC and resin composite restorations. Subgingivally located Class III restorations were placed in 17 patients. Each patient received one of each of the experimental materials. All patients were placed on an oral hygiene regime 1-year after finishing of the restorations. Gingivitis was induced during a one-week period without oral hygiene. The gingival condition was assessed by sampling of gingival crevicular fluid (GCF), registration of the amount of bacterial plaque and by registration of bleeding after gentle probing of the entrance of the gingival sulcus (SBI) on the experimental filling- and control-enamel surfaces at days 0 and 7. No differences were seen in plaque and gingival index scores between the materials at both days. The GCF increased significantly for all surfaces during the experimental gingivitis period. At day 7 significantly lower GCF was sampled around the enamel surfaces. In conclusion, the differences between the materials did not result in measurable differences concerning clinical or subclinical signs of gingivitis.

Adult↗
PubMed2005

Effect of three surface conditioning methods to improve bond strength of particulate filler resin composites.

The use of resin-based composite materials in operative dentistry is increasing, including applications in stress-bearing areas. However, composite restorations, in common with all restorations, suffer from deterioration and degradation in clinical service. Durable repair alternatives by layering a new composite onto such failed composite restorations, will eliminate unnecessary loss of tooth tissue and repeated insults to the pulp. The objective of this study was to evaluate the effect of three surface conditioning methods on the repair bond strength of a particulate filler resin-composite (PFC) to 5 PFC substrates. The specimens were randomly assigned to one of the following surface conditioning methods: (1) Hydrofluoric (HF) acid gel (9.5%) etching, (2) Air-borne particle abrasion (50 microm Al2O3), (3) Silica coating (30 microm SiOx, CoJet-Sand). After each conditioning method, a silane coupling agent was applied. Adhesive resin was then applied in a thin layer and light polymerized. The low-viscosity diacrylate resin composite was bonded to the conditioned substrates in polyethylene molds. All specimens were tested in dry and thermocycled (6.000, 5-55 degrees C, 30 s) conditions. One-way ANOVA showed significant influence of the surface conditioning methods (p < 0.001), and the PFC types (p < 0.0001) on the shear bond strength values. Significant differences were observed in bond strength values between the acid etched specimens (5.7-14.3 MPa) and those treated with either air-borne particle abrasion (13.0-22.5 MPa) or silica coating (25.5-41.8 MPa) in dry conditions (ANOVA, p < 0.001). After thermocycling, the silica coating process resulted in the highest bond values in all material groups (17.2-30.3 MPa).

Acid Etching, Dental↗
PubMed1989

The teaching of posterior composites: a worldwide survey.

The findings of a worldwide survey of the teaching of posterior composites have been reported. In most schools in at least Africa, Australasia, Europe, North America and Japan (mean response, 70 per cent) the undergraduate course in operative dentistry includes some consideration of posterior composites. However, the teaching in relation to these materials is typically limited and rarely includes practical exercises let alone requirements to gain clinical experience of the use of these materials. The data collected in respect of the materials and techniques considered appropriate for posterior composites was essentially consistent and in keeping with most of the recent authoritative literature in this field. It is concluded that many schools should review their approach to the teaching of posterior composites.

Bicuspid↗
PubMed1996

Biological monitoring of mercury vapour exposure by scalp hair analysis in comparison to blood and urine.

The reliability of human scalp hair as an indicator of mercury vapour exposure is contentious. In this study mercury concentrations in hair were compared with those in blood and urine of 20 dental students during their first "occupational" exposure to mercury vapour. Samples were collected before, at the end of the technical course of operating dentistry which lasted 6 weeks, and 3 months later. Mercury was measured by cold vapour atomic absorption spectrometry. In all biological media studied, mercury levels significantly (P < 0.05) reflected exposure to mercury vapour. After the time period without exposure mercury content decreased. Hair mercury levels were correlated to those in erythrocytes at sampling times 1 and 3 (r = 0.686 and r = 0.492) and to the frequency of fish consumption at sampling time 1. It is concluded that hair may be used as an indicator of internal uptake of mercury provided that it was not externally exposed to mercury vapour. In cases of occupational exposure to mercury vapour, hair is an useful tool for monitoring external exposure.

Adult↗
PubMed2004

Comparison of the shear bond strength of 2 self-etch primer/adhesive systems.

Conventional adhesive systems use 3 different agents-an enamel conditioner, a primer solution, and an adhesive resin for bonding orthodontic brackets to enamel. A unique characteristic of some new bonding systems in operative dentistry is that they combine the conditioning and priming agents into a single application. Combining conditioning and priming saves time and should be more cost-effective to the clinician and indirectly to the patient. The purpose of this study was to assess and compare the effects of mix and no-mix self-etch primers/bonding systems on the shear bond strengths of orthodontic brackets. The brackets were bonded to extracted human molars according to the following protocols. In group I, a self-etch acidic primer/adhesive system, Transbond Plus (3M Unitek, Monrovia, Calif), was applied on the enamel surface as suggested by the manufacturer; it has 2 components that must be mixed before use. The brackets were then bonded with Transbond XT and light-cured for 20 seconds. In group II, a no-mix self-etch bracket adhesive system, Ideal 1 (GAG International, Islandia, NY), was applied to the teeth as suggested by the manufacturer. The self-etch primer has 1 component that does not need to be mixed before use. The brackets were then bonded with the adhesive and light-cured for 20 seconds. The in vitro findings indicated that the shear bond strength comparisons (t = 0.681) of the 2 adhesive systems were not significantly different (P =.501). The mean shear bond strength of the 2-component acid etch primer was 5.9 +/- 2.7 MPa, and the mean for the 1-component system was 6.6 +/- 3.2 MPa. The clinician should consider the bond strength and the ease of application of the various components of the bracket bonding systems available on the market.

Dental Bonding↗
PubMed2005

Bone morphogenetic proteins in dentin regeneration for potential use in endodontic therapy.

The human dentition is indispensable for nutrition and physiology. The teeth have evolved for mastication of food. Caries is a common dental problem in which the dentin matrix is damaged. When the caries is deep and the dental pulp is exposed, the pulp has to be removed in many cases, resulting ultimately in loss of the tooth. Therefore, the regeneration of dentin-pulp complex is the long-term goal of operative dentistry and endodontics. The key elements of dentin regeneration are stem cells, morphogens such as bone morphogenetic proteins (BMPs) and a scaffold of extracellular matrix. The dental pulp has stem/progenitor cells that have the potential to differentiate into dentin-forming odontoblasts in response to BMPs. Pulpal wound healing consists of stem/progenitor cells release from dental pulp niche after noxious stimuli such as caries, migration to the injured site, proliferation and differentiation into odontoblasts. There are two main strategies for pulp therapy to regenerate dentin: (1) in vivo method of enhancing the natural healing potential of pulp tissue by application of BMP proteins or BMP genes, (2) ex vivo method of isolation of stem/progenitor cells, differentiation with BMP proteins or BMP genes and transplantation to the tooth. This review summarizes recent advances in application of BMPs for dentin regeneration and possible use in endodotic therapy.

Animals↗
PubMed2005

Influence of the application time on the penetration of different dental adhesives and a fissure sealant into artificial subsurface lesions in bovine enamel.

UNLABELLED: Sealing of approximal enamel lesions by infiltration with low viscous resins seems to be a promising approach in non-operative dentistry and should bear advantages compared to remineralization or invasive treatment. OBJECTIVE: The aim of this in vitro study was to evaluate the penetration ability of five dental adhesives and a fissure sealant into initial enamel lesions for an application time of either 15 s or 30 s. METHODS: In each of 54 specimens of bovine enamel, three windows were demineralized for 14 days. Subsequently, two windows were etched with phosphoric acid for 5s in order to degrade the surface layer, whereas one window served as untreated control. The specimens were randomly divided into six groups and a fissure sealant as well as five different adhesives were applied onto the subsurface lesions and allowed to penetrate for either 15 or 30 s. Overlying material was wiped away and the resins were light cured. To visualize the penetrated resins and the remaining pore structures, the specimens were infiltrated with a low viscous fluorescent resin and studied using a Confocal Laser Scanning Microscope (CLSM). RESULTS: For Helioseal, Heliobond, Resulcin Monobond, and Excite an application time of 30s resulted in significantly higher (p < 0.05; t-test) penetration depths (47-105 microm) compared to 15s (29-49 microm). SIGNIFICANCE: Helioseal, Heliobond, Resulcin Monobond, and Excite are suitable for sealing artificial subsurface enamel lesions in vitro. After an application time of 30 s a significant deeper penetration could be observed for these materials.

Acid Etching, Dental↗
PubMed2002

Dentin bonding as a function of dentin structure.

The traditional principles of operative dentistry have been challenged since Dr. Buonocore introduced the aid-etch technique in 1955. In spite of the numerous changes in clinical protocols and adhesive techniques, adhesion to dentin remains difficult. The importance of micromechanical bonding to dentin has been recognized over the last decade. Researchers now believe that dentin adhesion relies primarily on the penetration of adhesive monomers into the filigree of collagen fibers left exposed by acid etching. Two main strategies are currently in use for bonding to enamel and dentin: the self-etch technique and the total-etch technique. The efficiency of either bonding strategy depends very much on the dentin substrate used for bonding. Laboratory tests use ideal dentin from extracted teeth, which does not reflect the clinical reality. Clinical studies are the ultimate test for any dental adhesive material.

Clinical Trials as Topic↗
PubMed2000

Intra-oral topical anaesthetics: a review.

OBJECTIVE: This review considers the use of topical anaesthetics in the mouth to reduce the discomfort of local anaesthetic injections and intra-oral operative procedures. DATA SOURCES: Electronic literature search using Pub Med, manual search of references within papers found by the primary search and manual searching of abstracts from scientific meetings. STUDY SELECTION: The articles selected for this review investigate or used topical anaesthesia in dental procedures. CONCLUSIONS: The use of topical anaesthetics does not guarantee pain-free dental local anaesthesia. Efficacy is dependent upon the duration of application and the gauge of needle used. Evidence is available that the use of topical anaesthesia alone is sufficient to perform some intra-oral procedures including periodontal manipulations, operative dentistry and oral surgery.

Administration, Topical↗
PubMed2006

Challenges to teaching posterior composites in the United Kingdom and Ireland.

Recent surveys from general dental practice have found increased placement of direct composite resin restorations in occlusal (Class I) and occlusoproximal (Class II) cavities in permanent teeth by general dental practitioners. This has been matched, and possibly driven, at least in part, by the development of new composite resin materials and bonding technologies. Recent studies by the authors have found an increase in the teaching of Class I and Class II composite resin restorations in the UK, Ireland, the US, and Canada. The increased teaching in the UK and Ireland, however, was not as great as in North America, and several worrying trends were observed. The aim of this paper is to discuss these trends and related factors considered important to the necessary further development of the teaching of Class I and Class II direct composite resin restorations, let alone modern operative dentistry in general, in the UK and Ireland.

Acrylic Resins↗
PubMed2002

Effect of a fluoride-releasing self-etch acidic primer on the shear bond strength of orthodontic brackets.

Conventional adhesive systems use three different agents--an enamel conditioner, a primer solution, and an adhesive resin--during the bonding of orthodontic brackets to enamel. A unique characteristic of some new bonding systems in operative dentistry is that they combine the conditioning and priming agents into a single application. Combining conditioning and priming saves time and should be more cost-effective to the clinician and indirectly to the patient. The purpose of this study was to assess and compare the effects of self-etching primers, including a fluoride-releasing primer, on the shear bond strength of orthodontic brackets. The brackets were bonded to extracted human teeth according to one of four protocols. In group 1 (control), teeth were etched with 37% phosphoric acid; after the sealant was applied, the brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif) and light cured for 20 seconds. In group 2, a self-etch acidic primer (3M ESPE, St Paul, Minn) was applied as suggested by the manufacturer, and the brackets were then bonded with Transbond XT as in the first group. In group 3, an experimental self-etch primer EXL #547 (3M ESPE) was applied to the teeth as suggested by the manufacturer, and the brackets were then bonded as in groups 1 and 2. In group 4, a fluoride-releasing self-etch primer, One-Up Bond F (J. Mortia, USA Inc. Irvine, Calif) that also has a novel dye-sensitized photo polymerization initiator system was applied as suggested by the manufacturer, and the brackets were then bonded as in the other groups. The present in vitro findings indicated that the shear bond strengths of the four groups were significantly different (P = .001). Duncan multiple range tests indicated that One-Up Bond F (mean +/- SD strength, 5.1+/-2.5 MPa) and Prompt L-Pop (strength, 7.1+/-4.4 MPa) had significantly lower shear bond strengths than both the EXL #547 self-etch primer (strength, 9.7+/-3.7 MPa) or the phosphoric acid etch and the conventional adhesive system (strength, 10.4+/-2.8 MPa).

Acid Etching, Dental↗
PubMed2001

Effect of a self-etch primer/adhesive on the shear bond strength of orthodontic brackets.

Conventional adhesive systems use 3 different agents (an enamel conditioner, a primer solution, and an adhesive resin) during the bonding of orthodontic brackets to enamel. A unique characteristic of some new bonding systems in operative dentistry is that they combine the conditioning and priming agents into a single product. Combining conditioning and priming saves time and should be more cost-effective to the clinician and, indirectly, to the patient. The purpose of this study was to determine the effects of the use of a self-etch primer on the shear bond strength of orthodontic brackets and on the bracket/adhesive failure mode. Brackets were bonded to extracted human teeth according to 1 of 2 protocols. In the control group, teeth were etched with 37% phosphoric acid. After the sealant was applied, the brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif) and light cured for 20 seconds. In the experimental group, a self-etch acidic primer (ESPE Dental AG, Seefeld, Germany) was placed on the enamel for 15 seconds and gently evaporated with air, as suggested by the manufacturer. The brackets were then bonded with Transbond XT as in the first group. The present in vitro findings indicate that the use of a self-etch primer to bond orthodontic brackets to the enamel surface resulted in a significantly (P = .004) lower, but clinically acceptable, shear bond force (mean, 7.1 +/- 4.4 MPa) as compared with the control group (mean, 10.4 +/- 2.8 MPa). The comparison of the adhesive remnant index scores indicated that there was significantly (P = .006) more residual adhesive remaining on the teeth that were treated with the new self-etch primer than on those teeth that were bonded with the use of the conventional adhesive system.

Acid Etching, Dental↗
PubMed1980

Determinants of the quality of restorative dental care.

This article reports the results of an analysis to determine the relationships between the quality of restorative dental care for 1,466 patients and 9 categories of dentist characteristics for 102 volunteer Washington practitioners. In this study, patients were recalled and restorations were examined clinically. Questionnaires were administered to patients and dentists. The dependent measure is a weighted average of scores for operative dentistry and crown and bridge. Stagewise regression was used to adjust for differences in patient oral health and assessor bias. Models were postulated in each category of dentist characteristics and beta vectors were estimated by multiple regression. The best predictors formed a significant model (p = 0.000) which explained 26 per cent of the variance.

Attitude of Health Personnel↗
PubMed1999

Dental burs--what bur for which application? A survey of dental schools.

PURPOSE: The purpose of this study was to survey North American dental schools regarding recommendations for rotary instrumentation for fixed prosthodontic and operative procedures at the predoctoral and postgraduate level. MATERIALS AND METHODS: A 25-question survey was sent to 64 North American dental schools, of which 15 questions specifically related to rotary instrument recommendations. One questionnaire was addressed to the individual at each school having administrative responsibility for teaching tooth preparation techniques. A high response rate was assured by follow-up telephone calls and faxes. The distributions of bur recommendations for both predoctoral and advanced prosthodontic programs were analyzed by chi-squared tests at an a priori alpha = 0.05. RESULTS: Completed surveys were received from 58 of 64 dental schools, a response rate > 90%. Medium grit burs predominate in predoctoral education for gross tooth reduction for fixed prosthodontics, whereas coarse grit burs predominate at the graduate level (p < .05). The use of the diamond bur alone predominates for axial wall refinement, whereas the use of carbide burs or carbide burs in combination with diamond burs prevails for marginal refinement (p < .05). In predoctoral operative dentistry, recommendations for cavity outline form were similar at all dental schools (p > .05) and were principally tungsten carbide (WC) burs. Carbide burs are the instrument of choice for internal walls, but the WC bur alone or in combination with diamond burs is preferred for refining composite margins (p < .05). CONCLUSIONS: There is a broad consensus within North American dental schools on rotary instrumentation used by dental students. There is a greater use of coarser grit burs for gross tooth reduction in fixed prosthodontics at the postgraduate than predoctoral level.

Chi-Square Distribution↗
PubMed1991

The effect of glass ionomer cement and composite resin fillings on marginal gingiva.

Glass ionomer cement and composite resin are the most popular restorative materials in operative dentistry today. Earlier studies have shown more crevicular exudate around different types of composite resins than around intact enamel surfaces. The aim of this study was (1) to investigate plaque, retention on and the condition of the gingiva around, 1-year-old, subgingivally located, glass ionomer cement and composite resin fillings, and (2) to compare the initiation of gingival inflammation around these materials with that around enamel during a 14-day period of experimental gingivitis. Plaque index, gingival index, bleeding on probing and crevicular fluid were recorded and compared intra-individually. The amount of plaque and the degree of gingivitis adjacent to the composite fillings were not significantly higher than those for the glass ionomer cement and enamel surfaces in both the cross sectional and the experimental gingivitis study. Composite resin surfaces showed significantly higher crevicular fluid levels than did enamel at all days in the experimental gingivitis study. Glass ionomer cement showed significantly higher values at day-0 and day-7.

Adult↗
PubMed2000

Demineralisation and remineralisation of dentine caries, and the role of glass-ionomer cements.

In accordance with the principles of modern operative dentistry, to conserve tooth structure and to use therapeutic restorative materials, an understanding of the carious process in dentine and the biological properties of glass-ionomer cements (GICs) are necessary. Delineation of the outer necrotic from the inner vital and remineralisable carious dentine allows for the preservation of tooth structure. This delineation is not possible when relying on visual and tactile perceptions, but requires the use of a caries detecting dye. GICs are ideal dentine substitutes because of their anticariogenic properties, stable long-term ionic bonding, and ability to assist the process of remineralization. The range of usage of these restorative materials continues to expand with the development of improved products.

Apatites↗
PubMedDate not supplied

How 'clean' must a cavity be before restoration?

The metabolic activity in dental plaque, the biofilm at the tooth surface, is the driving force behind any loss of mineral from the tooth or cavity surface. The symptoms of the process (the lesion) reflect this activity and can be modified by altering the biofilm, most conveniently by disturbing it by brushing with a fluoride-containing toothpaste. The role of operative dentistry in caries management is to restore the integrity of the tooth surface so that the patient can clean. Thus, the question, 'how clean must a cavity be before restoration?' may be irrelevant. There is little evidence that infected dentine must be removed prior to sealing the tooth. Leaving infected dentine does not seem to result in caries progression, pulpitis or pulp death. However, some of the bacteria survive. What is their fate and if they are not damaging, why is this?

Dental Caries↗