December 1, 2010
by George Freedman, DDS, FAACD, FACD
A mere 20 years ago, fourth generation adhesives revolutionized restorative dentistry by offering a predictable technique for bonding to both enamel and dentin.1 Less than five years later, advances in ionomer and resin technologies provided clinically successful dentin and enamel replacement. In 2003, the first selective preparation burs that could differentiate healthy and unhealthy dentin were introduced.2 These were all revolutionary innovations that significantly altered the practice of dentistry. Within a decade, adhesive-resin and composites had displaced amalgam as the mainstream restorative materials.
The intervening years have seen the development of improved fifth and seventh generation adhesives,3,4 microhybrid and nanohybrid composites, LED curing lights, soft tissue lasers,5,6,7 and a host of other adjunct technologies that make dental treatment better, easier, faster,8 and more predictable.9,10 These innovations have been evolutionary, rather than revolutionary, building upon the existing science by gradual improvement and facilitation.
The three major clinical concerns encountered by practitioners in recent years have included:1. The end-point of cavity preparation (how to differentiate between infected and affected dentin and how much tooth structure must be removed to assure long-term operative success?)11,12,132. The disinfection of the prepared dentinal tissue (how to eliminate the remaining bacteria to prevent redecay?),14,15 and 3. The facilitation and simplification of the restorative protocol (how to reduce the numerous steps and technique sensitivities that arise in the restoration of function and form?)
Recent technological advances have done much to allay these concerns and to move dental practice towards ever greater clinical predictability.
Second generation Smartburs II (SSWhite, Lakewood, NJ) are self-limiting polymer burs that have been developed to address the clinical problem of preparation endpoint: the removal of infected dentin (softened tooth structure that cannot be remineralized)16 but the conservation of demineralized dentin (demineralized tooth structure that can be healed and remineralized). (Fig. 1) The slow speed Smartbur II relies on tooth structure hardness, and not tissue staining, to scientifically determine the endpoint. Its specifically designed Knoop hardness (harder than diseased dentin but softer than healthy dentin) allows the bur to selectively remove soft carious dentin while not cutting the harder healthy dentin.
A carbide or diamond bur can inadvertently penetrate through the thin remaining dentin into the pulp (Figs. 2, 3) the Smartbur II, on the other hand, is degraded by healthy dentin and ceases to cut (Figs. 4, 5). Smartburs II are used after the initial caries access preparation has exposed the deep, underlying caries. In cases where the caries is exposed (Fig. 6), these instruments can typically be utilized without the need for local anesthetics because they do not traumatize or open healthy dentinal tubules (Fig. 7).
It is well established that some bacteria remain in the prepared tooth structures, no matter how thorough the preparation process, and despite a tactile firmness and non-stained appearance. It is now possible to greatly decrease the likelihood of viable bacteria beneath the restoration by chemo-therapeutic methods that can penetrate as far as 2-3mm into the remaining enamel or dentin. These techniques effectively destroy bacterial viability and permit the subsequent remineralization of compromised tooth structures.
The technologies that have been shown to be effective surface bactericidals are:
This compact unit utilizes tolonium chloride to specifically stain liposomes in bacterial cell walls. The stain is subsequently targeted by a red diode light that releases oxygen ions. (Fig. 9) These ions break open the liposomes, rupturing the cell walls, and killing the bacteria.
Simplification of the Restorative Protocol
Most restorative protocols require numerous materials, each selected for particular beneficial properties, numerous steps, and a cumulatively complex description of the specific sequence that must be followed exactly. For example, microhybrid composites have excellent compressive strength for occlusal surfaces BUT they may not flow and adapt to margins and undercut areas of the preparation and can be difficult to sculpt. Flowable composites can adapt readily to the micro-anatomy of the tooth surface and are very polishable BUT cannot withstand the masticatory forces of direct occlusal contact.Beautifil Flow Plus (Shofu, San Marcos, CA) introduces a new category of restorative material: the “injectable” flowable composite resin. (Fig. 14) Based on Giomer chemistry, it is neither a conventional composite nor a flowable resin; Flow Plus is a unique blend of these materials with the benefits of both. Its high strength resin matrix is densely packed by fillers optimized to 67%.
Beautifil Flow Plus F O3 has a higher yield point than other flowables; thus, it is not deformed by the strong occlusal forces placed on the posterior teeth. Due to its excellent physical properties, Beautifil Flow Plus is indicated for restoring both anteriors and posteriors, and it is suitable for the occlusal surfaces of posterior teeth.
Two viscosities are available, a sculptable non-flow (F 00) (Fig. 15) and a low-flow (F 03) (Fig. 16), which are used together in the Resin Cone Technique. Both are suitable for the occlusal surfaces of posterior teeth. The highly elastic Beautifil Flow F 10 is placed after the adhesive for interface stress relief. Then, the non-flow is injected to form cusps and marginal ridges. It injects smoothly from the syringe, holds its shape, and does not develop a dispensing “horn”. Beautifil Flow Plus is not subject to technique sensitivity, and the Cone Injection Technique offers an important time advantage when compared to the layering technique. Beautifil Flow Plus 03 is placed last to finalize the occlusal anatomy of the restoration and to seal the marginal areas.
Used individually, or preferably together, these innovative techniques and materials provide practical clinical solutions to the concerns listed above. The following demonstration indicates an effective step-by-step protocol that incorporates the latest advances in restorative dentistry.
The rubber dam is punched and lubricated with water soluble Wink (Pulpdent, Watertown, MA) (Fig. 17) to facilitate its insertion through interproximal contacts without tearing. The Vita Easyshade Compact (Vident, Brea, CA) determines the shade of the restorative material at the beginning of the procedure, either before the rubber dam is placed, or immediately afterwards. (Fig. 18) It is important to record the shade while the tooth is still moist; once it is desiccated, the tooth will app
ear unnaturally chalky and opaque. The tooth is air-dried and the CarieScan PRO caries indicator (CarieScan, Dundee, United Kingdom) (Fig. 19) is utilized to confirm the location and the extent of the decay.25,26,27,28 (Fig. 20)
Access through the enamel is developed with a Great White Gold #2 carbide29 (Fig. 21) or a TDA #849 diamond (Fig. 22) high speed bur (both from SSWhite, Lakewood NJ).30 Once the deep decay is exposed, The Smartbur II selectively removes the soft carious (infected) dentin. (Fig. 23) The structure of the Smartbur II is designed to automatically determine the preparation end-point; any further rotation of the bur in the cavity simply abrades the bur, not the dentin. This leaves the harder, remineralizable (affected) dentin, covering the pulp chamber, intact. (Fig. 24)
The restorative process begins with an optional etching step; 7th generation adhesives do not require a separate etching step. A brief etch, 15 seconds or less, is unlikely to harm the bonding strength of the dental surfaces. Etch-Rite (Pulpdent, Watertown, MA) is applied to the enamel first and then the dentin (Fig. 25) and rinsed off with copious water less than 15 seconds later. (Fig. 26) Then, the prepared tooth surfaces are disinfected with the Aseptim Plus, (Fig. 27) Ozonics, (Fig. 28) or Healozone. (Fig. 29) Each of these treatments takes one minute or less of chairtime, and offers a greatly improved restorative predictability. Beautibond 7th generation single-component, single-step adhesive (Shofu, San Marcos, CA) is scrubbed onto all prepared dentin and enamel surfaces. (Fig. 30) It is left undisturbed for 10 seconds, and is then completely dried with an oil-free air syringe. (Fig. 31) The Beautibond is polymerized with a Fusion high power LED curing-light (DentLight, Richardson, TX). (Fig. 32)
Next, the cavity is filled utilizing the innovative resin Cone Technique (as opposed to the more laborious and time consuming layering technique). Sculptable Beautifil Flow Plus F 00 is injected onto the bonded surface of the preparation; (Fig. 33) the composite is formed into cones at the bases of the buccal cusps (Fig. 34) as it adapts intimately to the preparation. Since Flow Plus 00 is a non-flow resin, it stays where it is placed until curing. The Beautifil Flow Plus 00 is then injected to form the cones at the bases of the lingual cusps, (Fig. 35) from cavity floor to the occlusal, until all four cusp bases are restored (Fig. 36). The injected cones are then polymerized with the Fusion curing light. (Fig. 37) Once the cone build-up is complete, Beautifil Flow Plus F 03 is injected to seal the marginal areas (Fig. 38) and the valleys between the cones. (Fig. 39) The BFF F 03 is a low-flow material that can readily be shaped by the Duckhead instrument (Hu-Friedy, Chicago, IL) (Fig. 40) prior to final light-curing. (Fig. 41) The Duckhead composite instrument minimizes (and in many cases, eliminates) the need for occlusal adjustment and polishing, further improving the efficiency of the restorative protocol. The completed restoration (Fig. 42) demonstrates the clinical result of the technique and material enhancements that are available to the practitioner today.
Innovations in end-point determination, cavity surface disinfection, and the simplification of restorative techniques have again revolutionized dental practice. Mainstream clinical procedures are better, faster, and easier, and much more predictable in the long-term. OH
Dr. George Freedman is a founder and past president of the American Academy of Cosmetic Dentistry, a co-founder of the Canadian Academy for Esthetic Dentistry and a Diplomate of the American Board of Aesthetic Dentistry. Dr. Freedman sits on the Oral Health Editorial Board (Dental Materials and Technology) is a Team Member of REALITY and lectures internationally on dental esthetics and dental technology. A graduate of McGill University in Montreal, Dr. Freedman maintains a private practice limited to Esthetic Dentistry in Markham, Canada.
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References1. Nahabayaski N, Bonding mechanisms of resins and the tooth (in Japanese), Kokubyo Gakkai Zashi, J Stomat Society, Japan 1982 49:4102. Freedman G, Polymer Preparation Instruments, Dentistry Today, APRIL 2003 22:5 58-623. Freedman G, Fifth Generation Bonding Systems: State of the Art in Adhesive Dentistry, J Canadian Dental Assoc June 1997 63:6 347-3504. Freeman, G Seventh-Generation Adhesive Systems, Dentistry Today NOVEMBER 2002 21:11 106-1115. Goldstep, F, Diode Lasers For Periodontal Treatment: The Story So Far, Oral Health December 2009 44-466. Goldstep F, Soft Tissue Diode Laser : Where Have You Been All MY Life?, Oral Health July 2009 34-387. Goldstep F. Diode Lasers For Periodontal Treatment: The Story Continues, Dental Town June 2010 11:6 66-698. Freedman G, Goldstep F, Seif, T, Watch and wait is not acceptable treatment – Ultraconservative resin restorations, J Can Dent Assoc 1999, 65: 579-5819. Freedman G, Leinfelder K, Seventh Generation Adhesive Systems, Dentistry today 2002, 21:106-11110. Fusayama T, A simple pain-free adhesive restorative system by minimal reduction and tooth etcing, Tokyo Ishiyaku Euro America Inc, 199311. Fusayama T, Okuse K, Hosada H, Relationship between hardness, discoloration and microbial invasion in carious dentin, J Dent Res, 1966: 45: 1033-104612. Hosoya Y, Marshall SJ, Watanabe LG, Marshell GW, Microhardness of carious deciduous dentin, Oper Dent 2000: 25: 81-8913. Kutsch VK, Everett M, Process for the removal of soft tooth decay using a unique abrasive fluid stream, United States Patent 5,601,430, United States Patent and Trademark Office, February 11, 199714. Lynch E, Baysan A, Ellwood R et al, Effectiveness of two fluoride dentifrices to arrest root carious lesions, Am J Dent, 2000, 13:218-22015. Nyvad B, Fejerskov O, Scanning electron microscopy of early microbial colonization of human enamel and root surfaces in vivo, Scan J Dent Res, 1987, 95: 287-29616. Freedman G, Minimally Invasive Dentistry – The Management of Caries (Contributor)-Polymer Cutting Instruments section Quintessence Publishing Co. Ltd Surrey United Kingdom 2007 p 109-11017. Freedman G, Lynch E, Photo-Activated Disinfection, Oral Health Magazine, December 2009, 19-2518. Baysan A, Management of Primary Root Caries using Ozone Therapies, PhD Thesis, University of London, 2002 19. Bocci V, Luzzi E, Corradeschi F, et al, Studies on the biological effects of ozone:4 Cytokine production and glutathione levels in human erythrocytes, J Biol Regul Homeost Agents, 1993: 7: 133-13820. Ericson D, Zimmerman M, Raber H, Gotrick B, Bornstein R, Clinical evaluation of efficacy and safety of a new method for chemo-mechanical removal of caries, Caries Res 1999: 33: 171-17721. Baysan A, Lynch E, Grootveld M, The use of ozone for the management of primary root carious lesions, In: Albrektsson (ed): Tissue Preservation and Caries Treatment, Quintesssence 2001:3:49-6722. Baysan A, Whiley R, Lynch E, Anti-microbial effects of a novel ozone generation device on micro-organisms associated with primary root carious lesions in vitro, Caries Res 2000, 34: 498-50123. Bocci V, Biological and clinical effects of ozone, Has ozone therapy a future in medicine? Br J Biomed Sci 1999, 56: 270-27924. Bocci V, Ozone as a bioregulator, Pharmacology and toxicology of ozonetherapy today, J Biol Regul Homeost Agents 1996: 10:31-5325. Pitts N, How Electrical Caries Detection and Monitoring with CarieScan Can Help Deliver Modern Caries Management, Oral Health Magazine, July 2010 34-4326. Pitts NB and Stamm J, ICW-CCT Statements, Journal of Dental Research 2004 83: Special Issue C 125-12827. Detection, Assessment, Diagnosis and Monitoring of Caries – Editor NB Pitts, Karger Monographs in Oral Science, Vol 21 ISBN 978-3-8055-9184-
3, S Karger AG Basel (Switzerland) 200928. Pitts NB, Are we ready to move from operative to non operative/preventive treatment of dental caries in clinical practice? Caries Research 2004: 38:294-30429. Kimmel K, Optimal selection and use of rotary instruments for cavity and crown preparations. Dent Echo 1993: 63 (2) 63-6930. Siegel SC, von Fraunhofer JA, Cutting efficiency of three diamond bur grit sizes JADA 2000 131, 1706-1710
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