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Biomedical subjects

J F Roulet

Publications and source records attributed to J F Roulet.

At least 37 records · Page 2Linked to original sources
PubMed1999

Leakage in roots coronally sealed with different temporary fillings.

This study was aimed at determining the ability of different coronal temporary fillings to prevent corono-apical penetration of bacteria. A total of 103 human teeth, including three controls, were instrumented, obturated with gutta-percha, coronally sealed with either Cavit, Intermediate Restorative Material (IRM), glass-ionomer cement, Cavit/glass-ionomer cement, or IRM/glass-ionomer cement, respectively. Each root was fixed with wax between two chambers: the coronal chamber harboring soy broth with 10(8) colony-forming units of Streptococcus mutans/ml, the apical chamber containing sterile soy broth. The latter was checked daily for turbidity, indicating corono-apical penetration of bacteria. The Cavit group, the IRM group, and the Cavit/glass-ionomer cement group showed significantly more leakage than the glass-ionomer cement group of the IRM/glass-ionomer cement group. If a sample leaked, all except one (IRM/glass-ionomer cement) leaked before day 12. This in vitro study seems to indicate that only glass-ionomer cement and IRM combined with glass-ionomer cement may prevent bacterial penetration to the periapex of root-filled teeth over a 1-month period.

Calcium Sulfate↗
PubMed1999

A new method to assess the results of instrumentation techniques in the root canal.

In the present study, the shape of the root canal was assessed with pre- and postinstrumentation silicone impressions. Curved root canals of 30 extracted molars were instrumented with the Canal Leader (CL), the ProFile System (PF), and hand instrumentation (HI). Photographs from each impression were digitized, and the enlargement of the canals was computed by substracting the preinstrumentation from the postinstrumentation images. Technical errors of preparation were also recorded. There was no significant difference in total dentin removal between the systems. However, CL removed significantly more dentin from the convex side of the root canal than PF. Instrument separation occurred in five cases, only with PF. Roughness of canal walls was recorded significantly more often with the use of CL than with PF or HI. CL also produced a significantly higher incidence of elbow formation, compared with PF or HI. With this method of assessment, it was possible to record details and differences between the tested instrumentation techniques.

Dental Instruments↗
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↗
PubMed1999

Clinical study on the plaque-removing ability of a new triple-headed toothbrush.

The aim of this study was to determine the plaque removing ability of a new toothbrush with a u-shaped head (Superbrush) compared to a conventional manual toothbrush (Elmex) and an electric toothbrush with a rotating head (Braun Plak control). 36 healthy volunteers, aged 6-60 years, participated in this single blind cross-over study. They were randomly assigned to 3 groups (A, B, C) with 12 participants each. To obtain a plaque-free condition at the baseline, professional toothcleaning was performed in each participant. After instructions on how to use the toothbrushes, each group started the experiment with a different type of toothbrush. After 1 week of application, the Quigley-Hein plaque index (QHI) and the proximal plaque index (API) were used to assess the oral hygiene status of each participant. This was followed by 1 week of recess before each group switched to the next type of toothbrush. The duration of the study was 5 weeks. All examinations were performed by 1 examiner. Compared to the 2 other brushes, the Superbrush was more effective in removing plaque (medians of QHI: 0.84 versus 1.56 (Elmex) and 1.56 (Braun); p<0.001; medians of API: 0.69 versus 0.94 (Elmex) and 0.87 (Braun); p<0.001). The study indicated that the new toothbrush may be an effective alternative to commonly used toothbrushes.

Adolescent↗
PubMed1999

Caries prevention with fluoride varnish in a socially deprived community.

UNLABELLED: It has been suggested that specific preventive programs be developed for children with high caries risk. One possibility is to consider whole classes in socially deprived schools as caries-risk groups and perform an intensified preventive program for the entire class. OBJECTIVE: The purpose of this study was to evaluate the effectiveness of such a program which includes the application of a fluoride varnish (Duraphat). METHODS: The application of the varnish was offered three to four times a year in a community with low socio-economic status and a generally high caries level. Two hundred and sixty-nine children in six primary schools of Linden/Limmer, a district in Hannover, Germany, were allocated to a test or a control group. The test group received the fluoride varnish for 4 years whereas the control group received no professional fluoride application. DMFT was recorded at the beginning of the study and after 4 years. RESULTS: At the end of the study, children who had received a minimum of two fluoride applications per year showed a significantly lower caries increment in comparison with the control group (0.88 DMFT vs 1.39 DMFT, P < 0.05). CONCLUSIONS: It can be concluded that a minimum of two applications of the fluoride varnish Duraphat per year may be an effective measure in preventing caries in socially deprived children with high caries activity.

Child↗
PubMed1999

Marginal adaptation of compomer Class V restorations in vitro.

PURPOSE: The purpose of this in vitro study was to determine the marginal adaptation of different adhesives, including recently developed self-etching primers, in combination with compomers in Class V cavities. MATERIALS AND METHODS: In 80 extracted human teeth, divided into 10 groups of 8, Class V cavities were prepared (ca. 4 mm high, 3 mm wide, and 1.5 mm deep) with one half of the margin length in dentin. The one-bottle adhesives Prime & Bond 2.1, Syntac SC, and Espe OSB, and the self-etching primers Rasant F 2000 and Prompt L Pop were used in combination with compomers. Before and after thermocycling (TC), replicas were taken and a quantitative margin analysis using the SEM was performed at a magnification of 200x using defined criteria. RESULTS: The statistical analysis using Kruskal-Wallis and Bonferroni tests showed a significantly (p < 0.05) better marginal adaptation in enamel and dentin for the self-etching primers, and when the one-bottle adhesives were used in combination with the total-etch technique. CONCLUSION: Self-etching primers improve the marginal adaptation of compomer restorations in enamel.

Compomers↗
PubMed1999

The influence of a simplified application technique for ceramic inlays on the margin quality.

UNLABELLED: The adhesive luting technique for ceramic inlays requires a sequence of multiple steps that are cumber-some and time consuming. Furthermore, modifications of dentin bonding procedures may negatively influence the margin quality of ceramic inlays with cervical dentin finishing lines. PURPOSE: The objective of this study was to test the effect of a new, simplified procedure for dentin bonding on the margin quality of ceramic inlays. MATERIALS AND METHODS: Thirty-two MOD inlay cavities with cervical finishing lines in dentin were prepared into premolars. They were randomly divided into four groups (n = 8): In the balanced design, one parameter was the inlay material (Empress/Cerec) and the other the polymerization of the dentin bonding agent, before insertion of the inlay (P+) and after insertion of the inlay (P-). All inlays were inserted with Variolink II in combination with an enamel and dentin conditioning universal bonding agent (Etch & Prime 3.0). Two parameters were used to determine the inlay quality: (1) the fit, measured by the difference of the insertion depth into the cavity between try-in and cementation, and (2) a quantitative margin analysis in the SEM at a magnification of 200x, performed for the cervical segment before and after thermocycling, using epoxy replicas. RESULTS: In all four groups the inlays were > 5 microns deeper in the cavities than at the try-in session. This is explained by the substance loss from the etching. The measured difference for Cerec inlays inserted in cavities, where the bonding agent was not polymerized prior to insertion, was significantly larger. Margin analysis of the cervical segment revealed no statistical differences (P < 0.01) for both criteria tested. The median values for all groups were 100% for clinical acceptable margin and 0% for marginal opening. CONCLUSION: By using the universal bonding agent, high margin qualities on dentin and enamel are obtained with ceramic inlays even with the simplified approach.

Analysis of Variance↗
PubMed1999

Tensile bond strength of composite to air-abraded enamel.

PURPOSE: The purpose of this study was to test the tensile bond strength of composite resin to enamel surfaces treated with kinetic cavity preparation (KCP) and acid etching, respectively. MATERIALS AND METHODS: Plane labial surfaces of 280 human maxillary central incisors were treated with either KCP by varying treatment conditions or phosphoric acid gel. Composite samples were bonded to the pretreated surfaces with a bonding resin. After 24 hours specimens were loaded in tension in an Instron testing machine until bond failure. A two-way analysis of variance was used to determine significant differences. The failure sites were qualitatively evaluated by SEM. RESULTS: The determined tensile bond strengths and observed failure modes demonstrated that acid-etched enamel has a significantly higher bond strength to composite resin than KCP-treated enamel surfaces. CONCLUSION: KCP-prepared enamel has to be acid etched before bonding to composite resin.

Acid Etching, Dental↗
PubMed1997

Longevity of glass ceramic inlays and amalgam--results up to 6 years.

Ceramic inlays are discussed as one option for the substitution of amalgam restorations. The purpose of this study was to determine the longevity of glass ceramic inlays and amalgam restorations placed by the author: 123 class I and class II Dicor inlays placed with adhesive techniques and 163 amalgam class I and class II restorations were investigated. The observation time for the inlays varied from 4 to 82 months. The inlays were clinically investigated using modified USPHS criteria and documented photographically. Kaplan-Meier statistics were used to calculate the survival rate. From the 123 evaluated inlays 12 inlays (9.7%) failed: 7 due to fractures, 4 because of endodontic problems and 1 inlay was replaced due to persisting postoperative pain. All fractures could be explained by case selection errors. According to the Kaplan-Meier method, the estimated success rate after 6 years was 76% for the Dicor inlays and 87% for the amalgam restorations (control group). The difference was not statistically significant. It was concluded that Dicor inlays may be used as a successful alternative to amalgam.

Bicuspid↗
PubMed1997

Benefits and disadvantages of tooth-coloured alternatives to amalgam.

OBJECTIVES: To give the practising dentist scientifically based data to assist him/her in the responsible decision-making process necessary to weigh the options available to the patient if she/he prefers not to have an amalgam placed. DATA SOURCES: Based on the literature and on the research work, which was done in the author's department, the indications and limitations of the known alternatives of amalgam were formulated. DESCRIPTION OF ALTERNATIVES TO AMALGAM: With the exception of cast gold restorations, all alternatives require the strict use of adhesive techniques. When compared with similar amalgam restorations, placing composite restorations (if they are indicated) takes approximately 2.5 times longer because complex incremental techniques are needed. Despite all the efforts, direct composite restorations placed in large cavities still show unacceptable amounts of marginal openings. Tooth-coloured inlays are a better alternative for large restorations. These restorations must be inserted with adhesive techniques. With composite inlays it is difficult to achieve a composite-composite bond. Ceramic inlays may be micromechanically bonded to the luting composite. They all show clinically a good marginal behaviour and the use of ultrasonic energy may further simplify the application technique of aesthetic inlays. STUDY SELECTION: Papers describing the different techniques were used as a base for the corresponding chapter. To assess and compare the longevity of the different restoration types, literature data were used. We limited ourselves to papers reporting at least 5-year clinical data. Longitudinal, clinically controlled studies were preferred. However, to be more complete, retrospective, cross sectional studies were also included. LONGEVITY OF POSTERIOR RESTORATIONS: Amalgam shows excellent longevity data with studies up to 20 years. The average annual failure rate is 0.3-6.9%. Posterior composites are in the same range (0.5-6.6%), however, the study times are much shorter (max. 10 years). For tooth-coloured inlays much less data are available. Longevity is reported up to 6 years with annual failure rates of 0.6-5%. CONCLUSIONS: All aesthetic alternatives to amalgam require more complex procedures and more time. If cost benefit considerations are a concern, amalgam is still the most convenient restorative material for posterior teeth.

Bicuspid↗
PubMed1996

Inlay restorations.

This encyclopedic article on inlays reviews detailed clinical techniques, the spectrum of inlay materials, and supporting clinical performance data. Clinical recommendations are based on the results of laboratory and much clinical performance research.

Bicuspid↗
PubMed1995

Effects of treatment and storage conditions on ceramic/composite bond strength.

During the past few years, the interest in using ceramic inlays and veneers has increased. New materials and methods have been introduced to bond these restorations to resinous materials. Since our knowledge of how to optimize such bonding is limited, the objective of this study was to test the hypothesis that various surface treatment variables and combinations of these variables affect the strength of the ceramic/composite interphase of ceramic inlays differently. The influences of material composition, surface-roughening method, silane treatment, silane heat treatment, and storage condition on bond strength were investigated. Three ceramics (Dicor, Mirage, Vitabloc), three surface-roughening methods (etching, sandblasting, grinding), three silane treatments (gamma-methacryloxypropyltrimethoxysilane [MPS], MPS+paratoluidine, vinyltrichlorosilane), two heat treatments (20 degrees C for 60 s, 100 degrees C for 60 s), and two storage conditions (24-hour dry, one yr in water at 37 degrees C) were studied. For each of the 108 combinations, five specimens were tested. Ceramic cylinders were treated according to group assignment and bonded to blocks of the same ceramic material with a dual-cured resin. The shear bond strength was determined, and the experimental factors were evaluated by analysis of variance. The results showed that surface-roughening method had the strongest effect on bond strength, while ceramic selection had the least significant effect. Of the surface-roughening methods, etching was associated with higher bond strength values than either sandblasting or grinding.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum Oxide↗
PubMed1994

Marginal integrity: clinical significance.

The marginal integrity of restorations is an important parameter as marginal gap formation is associated with recurrent caries and pulpal disease. Testing of marginal integrity in vitro is viewed with uncertainty due to interactions and interpretation problems. The clinical evaluation of marginal behaviour is also questionable due to the lack of reliable diagnostic skills of the clinician. The scientific community must recognize that in vitro and in vivo testing have severe limitations and accept that materials will be misjudged during evaluation processes.

Composite Resins↗
PubMed1994

Dye penetration in root canals filled with AH26 in different consistencies.

It is recommended that the powder to liquid ratio of AH26 be very high and that the mixture be warmed to decrease viscosity before insertion into the root canal. In this study, the effectiveness of the powder to liquid ratio and temperature were assessed using 60 root canals of maxillary central incisors randomly divided into four groups after their cleaning and shaping. The teeth were obturated by either lateral condensation or the single-cone technique using AH26 warmed or at room temperature. After exposure to basic fuchsin, the teeth were embedded and cross-sectioned using a diamond saw. The dye penetration was measured microscopically and reported as a percentage of the total circumference of the filling of each slice using a goniometric eye-piece. After statistical analysis, it was concluded that AH26 in combination with lateral condensation leads to less leakage when used at room temperature.

Bismuth↗
PubMed1993

Inlays and onlays.

Dentists must meet the increased demands of patients for esthetic dentistry. Because the substitution of amalgam with direct composite restorations is somewhat problematic and restricted to special indications only, the most suitable method is the esthetic inlay. All available systems are reviewed and described. These restorations must be inserted with adhesive techniques. The performance and the problems associated with these techniques are described in detail. Improvements in luting techniques, eg, the use of ultrasonic energy, may further simplify the application technique for esthetic inlays. For clinical success, the margin quality of adhesively luted inlays is essential. In vitro and in vivo studies with esthetic inlays report good clinical behavior of such restorations. However, until the results of long-term clinical studies are available, these systems should not be used on a routine basis as a substitute for amalgam.

Composite Resins↗