Restorative Challenges and How to Overcome Them

© Springer International Publishing AG 2018. Restoration of deep carious lesions may be challenging in clinical practice. Many generations of dentists have been trained to remove all weakened carious dentin. This may, however, easily lead to pulp exposure and subsequent endodontic treatment. Especially this type of treatment may weaken a tooth, and it has been documented that endodontically treated teeth are more prone to fracture. New insights in the pathology of caries and the importance of a well-sealing restoration have led to changing treatment concepts. Selective carious tissue removal allows to avoid pulp exposure, but may also compromise the longevity of the restoration, mainly because of mechanical and adhesive reasons. Moreover, residual carious dentin is challenging with regard to radiographic diagnosis. In this chapter, these restorative challenges and possible solutions are discussed.status: publishe

Sample size considerations for restoration-longevity randomized controlled trials

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Degradatie van de dentinehechting, te voorkomen met MMP-inhibitoren?

Doelstelling: Ets&spoel adhesieven demineraliseren het dentine volledig tot 5 µm diep. De vrijgelegde collageenvezels vormen samen met het adhesief hars de hybride laag, die zorgt voor de retentie van de composietvulling. Tijdens de applicatie van fosforzuur worden eveneens MatrixMetalloproteïnasen (MMP’s) vrijgezet (Pashley e.a., 2004). Deze enzymen kunnen collageenvezels afbreken en zo de hechting op termijn hypothekeren. Materiaal&Methode: Een twee- en drie-stappen ets&spoel adhesief (respectievelijk Scotchbond 1 XT, 3M-ESPE en OptiBond FL, Kerr) werden aangebracht op dentinevlakken geprepareerd van recent geëxtraheerde wijsheidstanden. Vervolgens werd het adhesief aangebracht en een opbouw in composiet (Clearfil APX, Kuraray) vervaardigd. Na 1 week, 3, 6 en 12 maanden werd de microtreksterkte bepaald en de degradatie van de hechting ultra-morfologisch geëvalueerd m.b.v. transmissie- en scanning elektronenmicroscopie. Stockage van de micro-specimens in 10% natriumhypochloriet (NaOCl) fungeerde als ‘worst-case-scenario’, omdat voorgaand onderzoek heeft aangetoond dat zo’n behandeling de hechting uiterst snel aantast. Deze test werd herhaald na toevoeging van 2 verschillende MMP-inhibitoren aan de respectievelijke primers: 1) chloorhexidine, een niet-specifieke MMP-inhibitor, maar wel al veelvuldig toegepast in de tandheelkunde; 2) SB-3CT, een zeer specifieke MMP-inhibitor, maar niet geschikt voor toepassing in vivo. Resultaten: De hechtsterkte van beide adhesieven was significant (twee-weg ANOVA met herhaalde metingen, p<0.0001) gedaald na 12 maanden stockage in water. Na 12 maanden was vooral de hechting van het twee-stappen ets&spoel adhesief onvoldoende, getuige het grote aantal falingen voor de eigenlijke microtreksterktetest. De twee inhibitoren hadden een gelijkaardig effect, maar dit was verschillend voor beide adhesieven. Voor het drie-stappen ets&spoel adhesief was er een mild positief effect, terwijl er voor het twee-stappen ets&spoel adhesief een duidelijk negatief effect was. Conclusie: MMP-inhibitoren kunnen in bepaalde gevallen de hechting aan dentine over lange termijn verbeteren, maar het effect is beperkt en geldt slechts voor bepaalde adhesieven. Deze studie bevestigt andermaal dat de traditionele drie-stappen aanpak met een aparte etsgel, primer en adhesief hars effectiever is dan een ‘vereenvoudigde’ twee-stappen benadering met een gecombineerde primer/adhesief hars, ondanks dat op korte termijn bijna geen verschil genoteerd werd.status: publishe

Thirteen-year randomized controlled clinical trial of a two-step self-etch adhesive in non-carious cervical lesions

The objective of this randomized controlled clinical trial was to evaluate the 13-year clinical performance of a mild two-step self-etch adhesive in non-carious cervical lesions with and without prior selective phosphoric acid-etching of the enamel cavity margins.status: publishe

From Buonocore's Pioneering Acid-Etch Technique to Self-Adhering Restoratives. A Status Perspective of Rapidly Advancing Dental Adhesive Technology

This literature-based OPINION PAPER reflects in an introductory historical perspective on the rapid advancement of dental adhesive technology. Past and current techniques to bond to tooth tissue, in particular to dentin as the most challenging bonding substrate, are critically appraised. Including the historical perspective in (1), this paper focuses on fourteen items thought to be of primary importance with regard to the current status of dental adhesive technology. In (2) the primary mechanisms involved in adhesion to enamel and especially dentin are dealt with having (3) also revisited the previously introduced adhesion-decalcification concept (AD concept) as basis of biomaterial-hard tissue interaction; the worldwide accepted classification of today's adhesives into etch&rinse (E&R) and self-etch (SE) adhesives are presented in (4), along with presentation of their respective PLUS-MINUS balances in (5) and (6); nomination of the GOLD-STANDARD E&R (7) and SE (8) adhesives is based on evidence of successful laboratory and long-term clinical performance, resulting in a recommended 3-step full E&R bonding route in (9) and the preferred 3-step combined selective enamel E&R with 2-SE bonding route in (10); (11) description of the main bond-degradation pathways and eight strategies to preserve bond stability; (12) coverage of the PROS and CONS of the newest generation of UNIVERSAL adhesives. Looking into the future, some expected future developments in dental adhesive technology have been suggested in (13), along with (14) a first status determination of the latest research-and-development towards self-adhesive restorative materials that no longer require any pre-treatment.status: publishe

Bonding to fluorosed teeth

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State of the art of self-etch adhesives

This paper reflects on the state of the art of self-etch adhesives anno 2010. After presenting the general characteristics of self-etch adhesives, the major shortcomings of the most simple-to-use one-step (self-etch) adhesives are addressed. Special attention is devoted to the AD-concept and the benefit of chemical interfacial interaction with regard to bond durability. Finally, issues like the potential interference of surface smear and the more challenging bond to enamel for 'mild' self-etch adhesives are discussed.status: publishe

Nanoparticles in dentistry

OBJECTIVE: Nanoparticles having a size from 1 to 100nm are present in nature and are successfully used in many products of daily life. Nanoparticles are also embedded per se or as byproducts from milling processes of larger filler particles in many dental materials. METHODS AND RESULTS: Recently, possible adverse effects of nanoparticles have gained increased interest with the lungs being a main target organ. Exposure to nanoparticles in dentistry may occur in the dental laboratory, by processing gypsum type products or by grinding and polishing materials. In the dental practice virtually no exposure to nanoparticles occurs when handling unset materials. However, nanoparticles are produced by intraoral adjustment of set restorative materials through grinding/polishing regardless whether they contain nanoparticles or not. Nanoparticles may also be produced through wear of restorations or released from dental implants and they enter the environment when removing restorations. The risk for dental technicians is taken care of by legal regulations. Based on model worst case mass-based calculations, the exposure of dental practice personnel and patients to nanoparticles through intraoral grinding/polishing and wear is low to negligible. Accordingly, the additional risk due to nanoparticles exposure from present materials is considered to be low. However, more research is needed, especially on vulnerable groups (asthma or COPD). An assessment of risks for the environment is not possible due to the lack of data. SIGNIFICANCE: Measures to reduce exposure to nanoparticles include intraorally grinding/polishing using water coolants, proper sculpturing to reduce the need for grinding and sufficient ventilation of treatment areas.status: publishe

Extra Bonding Layer Compensates Universal Adhesive's Thin Film Thickness

PURPOSE: Universal adhesives (UAs) are applied in 2-step etch-and-rinse (2-E&R) or 1-step self-etch (1-SE) mode. This study investigated whether three UAs could benefit from a highly filled extra bonding layer (EBL), turning them into 3-E&R and 2-SE UAs, respectively, thus also compensating for the commonly thin film thickness of UAs. MATERIALS AND METHODS: Microtensile bond strength (μTBS) to bur-cut dentin of Clearfil Universal Bond Quick (C-UBq, Kuraray Noritake), G-Premio Bond (G-PrB, GC) and Prime&Bond Active (P&Ba, Dentsply Sirona), applied in E&R and SE mode without/with the adhesive resin (EBL) of OptiBond FL (Opti-FL_ar, Kerr), was compared to that of the 3-E&Ra OptiBond FL (Opti-FL; Kerr), which was also employed in 2-SE mode. As a cross reference, the SE primer of Clearfil SE Bond 2 (Kuraray Noritake) was combined with Opti-FL_ar (C-SE2/Opti-FL) and again applied in 2-SE and 3-E&R mode. μTBS was measured after 1 month of water storage (37°C) and additional 25,000 and 50,000 thermocycles (TC). All μTBS were statistically analyzed using three different linear mixed-effects models with specific contrasts (p < 0.05). RESULTS: Overall, the four parameters (adhesive, bonding mode, aging, EBL) significantly influenced μTBS. G-PrB and P&Ba benefited from EBL when applied in both E&R and SE bonding modes. In E&R mode, P&Ba generally revealed the highest µTBS; C-UBq presented an intermediate and G-PrB the lowest µTBS. No significant differences were found between different bonding modes. C-SE2/Opti-FL outperformed Opti-FL in 3-E&R and 2-SE_1 month/25k. CONCLUSION: The overall benefit of EBL on the 1-month and TC-aged bonding efficacy differed for the different UAs tested.status: publishe

Is secondary caries with composites a material-based problem?

Secondary caries (SC) is one of the most important reasons for the failure of composite restorations, and thus has wide-reaching implications for the longevity of affected teeth and the health expenditure. Yet, it is currently not known whether secondary caries with composites is a material-based problem. The objective was to review literature with regard to SC around composite restorations to obtain better insights in the mechanisms behind SC with composites.publisher: Elsevier articletitle: Is secondary caries with composites a material-based problem? journaltitle: Dental Materials articlelink: http://dx.doi.org/10.1016/j.dental.2015.09.001 content_type: article copyright: Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.status: publishe