Three-dimensional reconstruction of microleakage pattern using a sequential grinding technique

doi:10.1016/0300-5712(94)90091-4

Journal of Dentistry

Volume 22, Issue 6, December 1994, Pages 370-375

https://doi.org/10.1016/0300-5712(94)90091-4 Get rights and content

Abstract

Dye penetration tests are very commonly used to detect the absence of a fluid seal at the tooth-restoration interface. Airlocks in the marginal gap, leaching of water-soluble tracers during processing, and the failure of only a few sections to allow interpretation of the full pattern, limit these tests to low reproducibility and precision. The purpose of this present study was to generate high-resolution three-dimensional images of waterfast tracer patterns. Cylindrical class V (3 mm diameter, 2 mm deep) dentine-bonded resin composite restorations in buccal coronal dentine were thermally cycled (1000 ×, 8°C, 55°C, 30 s dwell at each temperature) and then silver stained using an initial vacuum (100 mmHg pressure). Each restoration was sequentially abraded from the free surface on wet 180 grit silicon carbide paper, producing up to 30 parallel surfaces at approximately 0.15 mm separation through the restoration down to the pulp. Images of the ground surfaces were captured, and assembled by a computer image analyser program to give a three-dimensional model of the tracer pattern. The maximum depths of tracer penetration below the reference surfaces were 3.00 mm, 2.09 mm, 3.16 mm and 2.29 mm for the four specimens. Projections of the models were viewed from several directions with sections in various locations to allow investigation of the full tracer pattern. This method allows the creation of high-resolution three-dimensional tracer patterns.

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Effects of silver diamine fluoride/potassium iodide on artificial root caries lesions with adjunctive application of proanthocyanidin
2019, Acta Biomaterialia
Citation Excerpt :
The complexes would dissociate into silver and fluoride ions as they diffused, react with and rebuild the depleted dentine crystals. Also, dentine is permeable to silver ions via tubules because these ions have a particle size much smaller than the dentine tubule width [65]. Lambert-Beer’s law predicts greater X-ray absorption in Ag than in Ca [66].
Treatment of carious root surfaces remains challenging due to the complex pathological processes and difficulty in restoring the original structure of root dentine. Current treatments targeting the de-/re-mineralisation processes are not entirely satisfactory in terms of the protection of the dentinal organic matrix and the highly organised structure of dentine. In this in vitro study, a cross-linking agent – proanthocyanidin (PA) was used in conjunction with a fluoride-based treatment – silver diamine fluoride/potassium iodide (SDF/KI) to putatively stabilise the organic dentinal framework as well as strengthen the collagen-mineral phase interaction. The effectiveness of this strategy was evaluated 24 h after application in terms of the distribution of ion uptake and microstructure of dentine after treatment as well as analysis of the nano-mechanical properties using a dynamic behaviour model. Results showed that individual use of SDF/KI significantly improved the surface microhardness and integrated mineral density (Z) up to 60 µm depth and the recovery of creep behaviour of demineralised dentine in the surface area compared to that treated with deionised distilled water (DDW). The combined treatment of PA and SDF/KI achieved a more homogenous mineral distribution throughout the lesions than SDF/KI alone; a more significant incremental increase in surface microhardness and Z was observed. Specifically, a superior effect on the subsurface area occurred with PA + SDF/KI, with significant improvements in microhardness, elastic modulus and recovery of creep behaviour of the demineralised dentine. Application of SDF/KI induced small discrete crystal formation distributed over the dentine surface and PA contributed to the formation of slit-shaped orifices of the dentinal tubules that were partially occluded.
Demographic transitions and improved oral health behaviour have resulted in increased tooth retention in elderly people. As a consequence, the risk of root dentine caries is increasing due to the age-associated gingival recession and the related frequent exposure of cervical root dentine. Root caries is difficult to repair because of the complex aetiology and dentine structure. The recovery of dentine quality depends not only on reincorporation of minerals but also an intact dentinal organic matrix and the organic-inorganic interfacial structure, which contribute to the biomechanics of dentine. With the capability of dentine modification, cross-linking agents were applied with a fluoride regimen, which improved its treatment efficacy of root caries regarding the distribution of ion uptake and recovery of dentine biomechanics.
3D-microleakage assessment of adhesive interfaces: Exploratory findings by μcT
2014, Dental Materials
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For the composite inlays that were luted using the 2-step etch-and-rinse composite cement Variolink-II (specimens C and D), the pattern of silver-nitrate penetration could not be detected by the μCT protocol, neither for enamel nor for dentin margins, because the attenuation of the adhesive material was similar to the attenuation of the silver nitrate, thereby hindering a proper segmentation (Figs. 3 and 4, specimens C and D). One of the first 3D techniques for detecting microleakage at tooth–composite interfaces involved the stepwise reduction of the test specimen by grinding and the conventional score-based stereomicroscopic quantification of tracer infiltration for each image at the grinding step [18]. Although this methodology was able to provide a volumetric distribution of the tracer penetration at the whole restoration interface, it was, at the same time, destructive, extremely laborious and time-consuming.
To explore the feasibility of a 3D-microleakage protocol for the evaluation of various configurations of adhesive–tooth interfaces.
Three different kinds of specimens were prepared: (1) a Class-I composite restoration placed without any bonding to maximize gap formation at the interface; (2) a glass-fiber post cemented with a self-adhesive composite cement into a prepared root canal; and (3) inlay MOD composite restorations placed with either a 1-step self-adhesive or a 2-step etch-and-rinse composite cement. After silver-nitrate (AgNO₃) infiltration, the specimens were scanned using a Skyscan 1172 X-ray microtomograph (μCT; Skyscan Bruker) at 100 kV, 100 μA and 7.8–9.5 μm resolution. Projection images were reconstructed, after which maximum-intensity projections (MIPs) and 3D-volumetric renderings were produced. For the inlays, an additional conventional stereomicroscopic (SM) microleakage evaluation was accomplished after specimen sectioning.
MIPs and 3D-renderings from specimens (1) and (2) revealed strongly varying microleakage patterns along the marginal gap/interface. For the specimens of setup (3), the high radiopacity of the 2-step composite cement hindered evaluation of the MIPs. MIP-microleakage patterns along the enamel margin of the restoration cemented with the 1-step composite cement corresponded well to the stereomicroscopic images.
The reported μCT-protocol revealed good sensitivity to detect AgNO₃ infiltration at the adhesive–tooth interface when considerable microleakage was present. When microleakage was less apparent and spread in a more diffuse pattern, evaluation with μCT was less sensitive compared to stereomicroscopic evaluation.
Microleakage of orthodontic band cement at the cement-enamel and cement-band interfaces
2010, American Journal of Orthodontics and Dentofacial Orthopedics
Citation Excerpt :
For this purpose in our study, 2 examiners (H.E. and M.U.) who were blinded to the cement types from another department of Erciyes University in Kayseri, Turkey, evaluated the microleakage. Microleakage, however, might not be similar on both sides on a banded tooth, although studies in restorative dentistry have assumed that assessment of 1 side represents the whole tooth.25 Airlocks in the marginal gap, leaching of water-soluble tracers during processing, and the failure of only a few sections to allow interpretation of the full pattern limit dye penetration tests to low reproducibility and precision.
Our objective was to determine and compare microleakage patterns of conventional glass ionomer cement (GIC), resin modified GIC (RMGIC), and polyacid-modified composite for band cementation.
Sixty freshly extracted third molars were randomly divided into 3 groups of 20 teeth each. Microetched molar bands in the 3 groups were cemented to enamel with one of three orthodontic cements: Ketac-Cem (3M ESPE, Gmbh, Seefeld, Germany), Multi-Cure (3M Unitek, Monrovia, Calif), and Transbond Plus (3M Unitek). A dye penetration method was used for microleakage evaluation. Microleakage was determined by a stereomicroscope for the cement-band and cement-enamel interfaces from both the buccal and lingual margins. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U tests.
The buccal sides had similar microleakage values compared with the lingual sides for the cement-enamel and cement-band interfaces with all cements. Statistical comparisons showed statistically significant differences among the band cements between both interfaces (P <0.001). When the cement systems were compared, conventional GIC showed the highest leakage scores between cement-band (median, 3.50 mm) and cement-enamel (median, 2.88 mm) interfaces. Teeth banded with RMGIC and modified composite showed similar microleakage scores, and both had less leakage (<1 mm) than conventional GIC.
Conventional GIC is associated with more microleakage than RMGIC and modified composite at both the cement-band and cement-enamel interfaces.
The accuracy of electrical method for microleakage evaluation by a three-dimensional analysis
2007, Journal of Dentistry
This in vitro study aimed to investigate the accuracy of an electrical method for the evaluation of microleakage by a three-dimensional analysis of dye penetration.
Coronal cavities were prepared on buccal, palatal or lingual surfaces in extracted human molars. The cavities were then filled with resin composites and were subjected to 10,000 load cycles (425 g). Before cavity preparation and after load cycling, physiological saline was applied and wiped off, and the change in conductance was measured across the margin of the restoration in each specimen. After dye penetration, the specimens were reduced by 100 μm in a direction parallel to the cavity floor, from the surface of the restoration to the cavity floor. The sequence of reducing the sections by 100 μm and image taking was repeated. Three-dimensional images of dye penetration were made and the proportions of the interface showing penetration were calculated.
Pearson's correlation coefficients between changes in conductance and the surface area of dye penetration, between these and the rate of dye penetration, and between these and the depth of dye penetration were 0.932, 0.920 and 0.732, respectively. The correlations were significant (p < 0.05).
The results of this electrical method for microleakage evaluation showed stronger correlations with the three-dimensional amount of marginal leakage (surface area of dye penetration and rate of dye penetration) than the two-dimensional amount (depth of dye penetration).
Three-dimensional evaluation of gap formation of cervical restorations
2005, Journal of Dentistry
In some studies gap formation has been evaluated in just one section of the restorative. This in vitro study aimed to design a quantitative three-dimensional method for evaluation of the contraction gap in restoratives.
Cervical cavities were prepared on buccal, palatal or lingual surfaces in human extracted molars and were then filled with resin composites. Specimens were reduced every 100 μm in a direction parallel to the tooth axis, and perpendicular to the cavity floor from one proximal side to the other. The sequence of reducing the sections by 100 μm, image taking (250×) and observation of these images (maximal 2500×) were repeated. Three-dimensional images of the contraction gap were made using analytical software and the proportions of the interface with gap formation calculated.
The mean proportions of the interface with gap formation of the self-etching system (Clearfil Liner Bond II Σ) was 41.7±6.3% and that of the self-priming system (Single Bond) was 38.2±3.9%; there was no significant difference.
Approximate three-dimensional images of the in vitro contraction gap could be drawn and the mean proportions of the interface with gap formation could be more precisely calculated than by previous methods.
Effect of energy density on properties and marginal integrity of posterior resin composite restorations
2004, Dental Materials
Objectives. The purpose of this study was to determine the minimal extent of cure required by the base of a Class 2 resin composite restoration (Z250, 3M ESPE, St Paul, MN, USA) that allows it to support the rest of the restoration and maintain its marginal seal under simulated clinical conditions.
Methods. Resin composite (Z250, 3M ESPE, St Paul, MN, USA) was placed incrementally or in bulk into Class 2 preparations in extracted human molar teeth and exposed to various light-curing energy densities. The restorations were subjected to 1000 thermal cycles (5–55 °C) and 500,000 fatigue cycles from 18 to 85 N using a stainless-steel sphere. Marginal integrity was evaluated using visual rating (ridit analysis) and microleakage. Degree of conversion (DC) and Knoop hardness (KHN) were determined at the occlusal and gingival surfaces using a reusable tooth template with identical preparation dimensions. Percentage of maximum DC and KHN were determined. Mechanical properties were tested in resin composite bars having similar KHN values as the resin composite at the gingival margins.
Results. Energy density had a significant effect on gingival marginal defects as determined by ridit analysis but not on microleakage. Water had a significant dissolving effect on gingival margin integrity at very low degrees of conversion and energy densities (4000 mJ/cm²). There was no overall significant effect of thermal–mechanical stressing on gingival marginal defects or microleakage.
Significance. Based on ridit analysis, a recommended lower limit of gingival margin acceptability in the bulk-filled Z250 resin composite restoration was created by 80% of maximum conversion, 73% of maximum hardness and approximately 70% of maximum flexural strength and modulus in the gingival marginal area.

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^☆: This method has been previously presented at the 71st General Session of the International Association for Dental Research, Chicago, 10–14 March 1993. (J Dent Res 1993; 72: 114. Abstract 88, special issue). It is part of ongoing work in the PhD programme of the first author.

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Original research reportThree-dimensional reconstruction of microleakage pattern using a sequential grinding technique☆

Abstract

J Dent

Dent Mater

J Dent

Dent Mater

Dent Mater

J Prosthet Dent

J Dent

J Dent

J Prosthet Dent

J Endod

Oral Surg Oral Med Oral Pathol

Dent Clin North Am

J Prosthet Dent

Materials used for filling teeth

Original research report
Three-dimensional reconstruction of microleakage pattern using a sequential grinding technique☆