QDT 2020 233
Inside Out: A Technique for Faster and More Predictable Layering
Fig 13 The dentin silicone key in place.
Fig 14a A mixture of e.max Ceram Power
Dentin A1 + Oc Dentin Orange 50% is
added in the cervical area.
Fig 14b Power Dentin A1 pure, a
high-value dentin, is placed.
Fig 15a In the incisal area, a translucent
dentin (DA1 + TN 50%) is placed.
Fig 15b The placement of all the effects
necessary to build a restoration is quick
and easy with the guidance of the silicone
Figs 16a and 16b Once the internal
layering is completed, the dentin key is
replaced by the enamel key to generate
the space necessary for the external layer.
Fig 17a Final result after bake.
Fig 17b The ﬁnal result after ﬁnishing is very predictable.
13 14a 14b
BRUGUERA ET AL
It is interesting to see the results obtained by different
technicians using the same model, masses, and silicone
keys. As shown in Figs 18 and 19, the results obtained are
quite similar. A numerical reading of the color results indi-
cate minimal difference, which demonstrates that using
the Inside Out technique will allow technicians to scale
ceramic restorations in their laboratories in a predictable
way. Not only does the technique provide predictability, but
approximately 30% savings of time.
Fig 18 The result obtained by different technicians is surprisingly similar.
Fig 19 The color is checked using the eLAB technique developed by Sascha Hein and minimal difference is found.
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QDT 2020 233Inside Out: A Technique for Faster and More Predictable LayeringFig 13 The dentin silicone key in place.Fig 14a A mixture of e.max Ceram Power Dentin A1 + Oc Dentin Orange 50% is added in the cervical area.Fig 14b Power Dentin A1 pure, a high-value dentin, is placed.Fig 15a In the incisal area, a translucent dentin (DA1 + TN 50%) is placed.Fig 15b The placement of all the effects necessary to build a restoration is quick and easy with the guidance of the silicone keys.Figs 16a and 16b Once the internal layering is completed, the dentin key is replaced by the enamel key to generate the space necessary for the external layer.Fig 17a Final result after bake.Fig 17b The ﬁnal result after ﬁnishing is very predictable.13 14a 14b15a 15b16a 16b17a 17b BRUGUERA ET ALQDT 2020234It is interesting to see the results obtained by different technicians using the same model, masses, and silicone keys. As shown in Figs 18 and 19, the results obtained are quite similar. A numerical reading of the color results indi-cate minimal difference, which demonstrates that using the Inside Out technique will allow technicians to scale ceramic restorations in their laboratories in a predictable way. Not only does the technique provide predictability, but approximately 30% savings of time.1819Fig 18 The result obtained by different technicians is surprisingly similar.Fig 19 The color is checked using the eLAB technique developed by Sascha Hein and minimal difference is found. Inside Out: A Technique for Faster and More Predictable Layering QDT 2020235MINIMALLY INVASIVE RESTORATIONS WITH INSIDE OUTCases requiring very little ceramic layering are now com-mon. But this does not mean they are any less difﬁcult; seeking balance between the interior and the exterior lay-ering is still required. To use the Inside Out technique with minimally invasive restorations, some parameters must be taken into account.In general, minimally invasive restorations will lack in-ternal dentin, requiring only the completion of some non-existent volume (for example, an incisal contour), in creas- ing the enamel volume and nothing more. The intermediate bake technique can be used for greater control of the transition between the restoration area with support and the area that does not have support. If Inside Out is used for this, in most cases it will not be necessary to work with both silicone keys, or at least as described so far.Consider the case shown in Fig 20. In this patient with lateral agenesis, the canines were moved orthodontically to replace the lateral incisors. The treatment plan was to restore the teeth with veneers from premolar to premolar with preparation only of the canines to facilitate their transformation into laterals (Fig 21). It was also planned to increase the value of the veneers by a minimum of two shades. As always, a diagnostic wax-up is the ﬁrst step. Already knowing that there will not be enough space derived from preparation, space will need to be generated by increasing the volume of the vestibular aspect in order to clarify the patient’s dentinal color. In this situation, an intermediate bake is in order. The enamel key will be obtained directly from the diagnostic wax-up and cut, as described previ-ously, on the vestibular aspect of the incisal edge. The ob-jective of this key is to provide the incisal position of the diagnostic wax-up and the ﬁnal volume of enamel (Fig 22). Once we have this silicone key, the diagnostic wax-up model is copied and 1.5 mm added to compensate for the Fig 20 Preoperative view of patient with lateral agenesis. Canines have been moved orthodontically to replace the lateral incisors. (Case by Dr Oscar González.)Fig 21 Only the canines will be prepared for the veneer restoration from premolar to premolar.Fig 22 Diagnostic wax-up from which the enamel key is obtained.2021 22 BRUGUERA ET ALQDT 2020236vertical contraction of the ceramic (Figs 23 to 26). Next, as shown in Figs 27 to 29, the dentin key that will support the internal layering is made. With these two silicone keys ready, the ceramic layering can begin.The silicone key is placed and the entire incisal area is lengthened with dentins and effects (Figs 30 and 31). Once the intermediate bake is done, all the vertical contraction that has been obtained can be seen (Fig 32). When the 23 2425 2627 28Fig 23 Diagnostic wax-up is copied.Fig 24 Compensation for contraction is begun.Fig 25 Average contraction is 1.5 mm.Fig 26 Compensation of the vertical contraction of the ceramic.Fig 27 The dentin key is made.Fig 28 The center of the incisal edge will be cut.Fig 29 Note the space generated for the ﬁrst bake.29 Inside Out: A Technique for Faster and More Predictable Layering QDT 2020237dentin key is replaced with the enamel key—remember that it was made using diagnostic wax-up without compen-sating for the contraction—you can see how everything done internally is perfectly placed (Fig 33). The space gen-erated by the enamel key is ﬁlled and the restoration baked, demonstrating how simply the diagnostic wax-up was replicated (Figs 34 to 39).Fig 30 Layering of dentins.Fig 31 After baking, internal characteristics, including mamel-ons and bluish triangles, are added.Fig 32 After intermediate bake, the vertical contraction is evident.Fig 33 Note how this ﬁrst bake is perfectly located in the diagnostic wax-up.Fig 34 Once the enamel is applied, the restorations follow the incisal guide generated in the diagnostic wax-up.Fig 35 Veneers recovered following the incisal guide.Figs 36a and 36b The volumetric resemblance of waxing and ﬁnished veneers is evident.30 3132 333436a 36b35 BRUGUERA ET ALQDT 2020238CONCLUSIONWith Inside Out, all the morphologic information and space position of the incisal edge of a diagnostic wax-up can be transferred to the ceramic restoration regardless of the lay-ering complexity. This technique not only simpliﬁes the ce-ramic layering, but also provides savings of about 30% of our working time and makes the outcome more predictable.Inside Out generates a similar effect to digitalization, in that it offers the possibility of increased laboratory produc-tivity and makes the technician’s hand less decisive in terms of ﬁnal quality. Using this technique, differences in results by technicians within the same laboratory decrease, since they are all guided by the same proportions of dentin and enamel. The great difference between the technicians will be in how they place and contrast the ceramic colors.Fig 37 Ceramic restorations so thin will have little color effect. In this case, the value was increased.Figs 38 and 39 Deﬁnitive restorations a few weeks after being cemented: veneers 0.2 mm/0.4 mm thick, without preparation and supragingival ﬁnal cementation. 38 3937 ANATOMY AND MORPHOLOGYFROM THE MASTERSHilton RiquieriThis beautiful atlas conveys not only the practical knowledge of dental anatomy but also the art of sculpting it in wax. The ideal anatomy of each dental structure is described in detail and the waxing techniques are beautifully illustrated step by step for visual reference. The author demonstrates that for every morphologic feature there is an explanation in nature, assigning signi cance to every minute feature of dental morphology. Organized by tooth and arch, this book views morphology through a clinical lens and repeatedly draws connections between anatomical features and clinical concepts. The fundamental knowledge presented in this text is essential for improving waxing and sculpting techniques and will be useful for students and specialists alike.332 pp; 1,507 illus; ©2019; (B7703); US $172Paulo Kano384 pp; 800 illus; ©2011; (BG095); US $280Shigeo Kataoka and Yoshimi Nishimura100 pp; 336 illus; ©2002; (B411X); US $78ESSENTIAL CLASSICSNEWHilton RiquieriThis beautiful atlas conveys not only the practical knowledge of dental anatomy but also the art of sculpting it in wax. The ideal anatomy of each dental structure is described in detail and the waxing techniques are beautifully illustrated step by step for visual reference. The author demonstrates that for every morphologic feature there is an explanation in nature, assigning signi cance to every minute feature of dental morphology. Organized by tooth and arch, this book views morphology through a clinical lens and repeatedly draws connections between anatomical features and clinical concepts. The fundamental knowledge presented in this text is essential for improving waxing and sculpting techniques and will be useful for students and specialists alike.332 pp; 1,507 illus; ©2019; (B7703); CALL: (800) 621-0387 (toll free within US & Canada) • (630) 736-3600 (elsewhere) 12/19FAX: (630) 736-3633 EMAIL: [email protected] WEB: www.quintpub.comQUINTESSENCE PUBLISHING CO INC, 411 N Raddant Rd, Batavia, IL 60510 The concept of using an injectable molding technique to manufacture various parts has been around for over a century.1,2 The ﬁ rst injection-molding machine was developed and patented by John and Isaiah Hyatt in 1872 for producing celluloid plastic parts.1,3 The next half-century saw the adoption of this process for the manufac-ture of items such as collar stays, buttons, and hair combs.3Over the course of its development, injection molding has been used by designers and engineers for myriad applica-tions with a host of materials—including glass, metals, con-fections, elastomers, and thermoplastic and thermosetting polymers—to fabricate a variety of complex shapes with high dimensional precision. It has been used in a variety of manufacturing industries, including aerospace, automotive, jewelry, avionics, biomedical, orthodontics, pharmaceutical, scientiﬁ c, electronic, and computer technology. In dentistry, this technique has been used in the laboratory fabrication of prosthetic appliances such as complete dentures, partial dentures, laboratory-processed acrylic and composite pro-visional restorations, and ceramic restorations.1,2Continued developments in adhesive technologies, the design of resin composite formulations, and innovative ap-plication techniques have revolutionized the delivery of minimally invasive direct resin composite restorations while improving the practice of dentistry. In some cases, compli-cated layering techniques are required that are dependent on the clinician’s skill and artistic ability. The injectable resin composite technique provides a simpliﬁ ed, precise, and predictable method for developing natural esthetic composite restorations while reducing chair time. Although not a panacea for all restorative challenges, this technique provides the patient and clinician with an alternative approach to various clinical situations. This technique is a unique and novel indirect/direct process of predictably translating a diagnostic wax-up or the anatomical form of the natural dentition of a preexisting diagnostic model into composite restorations. There are myriad applications for this technique using a highly ﬁ lled ﬂ owable (injectable) resin composite, including The Injection Resin Technique:A Novel Concept for Developing Esthetic RestorationsDouglas A. Terry, DDS1John M. Powers, PhD2Markus B. Blatz, DMD, PhD31 Private Practice, Houston, Texas; Adjunct Professor, Department of Restorative Sciences, University of Alabama at Birmingham, Birming-ham, Alabama, USA.2 Clinical Professor of Oral Biomaterials, Department of Restorative Dentistry and Prosthodontics, University of Texas Health Science Center at Houston, School of Dentistry, Houston, Texas, USA.3 Professor and Chair, Department of Preventive and Restorative Sciences, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania, USA.Correspondence to: Dr Douglas A. Terry, Institute of Esthetic & Restorative Dentistry, 12050 Beamer Road, Houston, TX 77089, USA. Email: [email protected] 2020 TERRY ET ALQDT 2020242emergency repair of fractured teeth and restorations; modiﬁcation and repair of prototypes and provisional res-torations, composite restorations (Class III, IV, and V; ve-neers), and pediatric composite crowns; resurfacing of occlusal wear on posterior composite restorations; estab-lishment of incisal edge length prior to esthetic crown lengthening; orthodontic space management; develop-ment of composite prototypes for copy milling; fabrication of an implant-supported composite provisional restoration; and repair of fractured or missing denture teeth.1,4–6 In ad-dition, this technique can be used to establish vertical di-mension and to alter occlusal schemes (anterior guidance and posterior disocclusion) prior to deﬁnitive restoration.1–3 Furthermore, this noninvasive technique is an integral tool for enhancing communication between the patient and the restorative team during treatment planning.1,2,4Developing transitional resin composite restorations us-ing the injectable technique is an excellent method for in-creasing the patient’s understanding of the planned clinical procedure and anticipated ﬁnal result.7 Transitional com-posite prototypes establish parameters for occlusal func-tion,8 tooth position and alignment,9 restoration shape and physiologic contour,10 restorative material color and tex-ture, lip proﬁle, phonetics, incisal edge position, and gingi-val orientation. This process also eliminates confusion and misunderstanding between the patient and the restorative team during the treatment-planning stage.7 It can reduce the potential for patient dissatisfaction and litigation be-cause the process is reversible, can be performed without preparation, and allows the patient to accept the visual and functional result before the deﬁnitive restorations are fab-ricated. In addition, the simple procedure helps to regulate the dimensions of the preparation design, ensures uniform spatial parameters for the restorative material, and in-creases the potential for a more conservative preparation design.4This injectable technique can also be used in the devel-opment and management of soft tissue proﬁles and in the design of the deﬁnitive restoration.11–14 The clinician and technician can use the technique as a guide for developing a preapproved functional and esthetic deﬁnitive restora-tion.15 In some cases, these transitional restorations can be worn for months or even years during long-term interdisci-plinary rehabilitation.2,4 However, this material and tech-1 23Fig 1 Preoperative facial view of the maxillary anterior segment of a 63-year-old patient who presented with incisal wear and fracture of the maxillary anterior teeth. The patient requested a conservative esthetic enhancement without orthodontic treatment. Clinical evaluation revealed multiple diastemas and cervical corrosion on the central incisors from lemon sucking.Fig 2 Development of a diagnostic wax-up that established new parameters (ie, esthetic, functional) for the ﬁnal restora-tions.Fig 3 A clear polyvinyl siloxane matrix was fabricated to replicate the diagnostic wax-up. The Injection Resin Technique: A Novel Concept for Developing Esthetic Restorations QDT 2020243nique should not be utilized as a ﬁnal restorative material for full-mouth rehabilitation. In certain clinical situations, this technique can be per-formed intraorally without anesthesia. A clear polyvinyl si-loxane (PVS) impression material is used to replicate the diagnostic wax-up, the anatomical form of the natural den-tition, or a preexisting diagnostic model. The clear matrix can be placed intraorally over the prepared or unprepared teeth and used as a transfer vehicle for the ﬂowable resin composite to be injected and cured1,2 (Figs 1 to 5).EMPIRICAL DATAFlowable composite materials have been evaluated in nu-merous studies16–40 since their inception. Although early ﬂowable formulations demonstrated poor clinical perfor-mance,1,16 some of the more recent studies34,37,38 indicate that the clinical performance of speciﬁcally tested next-generation ﬂowable (injectable) resin composites have similar or improved performance to speciﬁcally tested uni-versal resin composites. Attar and others23 showed that different ﬂowable composites possessed a wide range of mechanical and physical properties. Earlier studies by Gallo et al24 on speciﬁc ﬂowable resin composites sug-gested that these materials should be limited to small- and moderate-sized restorations having isthmus widths of one-quarter or less of the intercuspal distance.31 However, Torres et al38 reported that, after 2 years of clinical service, no signiﬁcant differences were found between Class II restorations restored with GrandioSO (VOCO) convention-al nanocomposites and those restored with GrandioSO Heavy Flow (VOCO) ﬂowable hybrid nanocomposites. A study by Karaman et al34 showed similar clinical perfor-mance over 24 months in restorations of noncarious cervi-cal lesions restored with conventional nanocomposites (Grandio, VOCO) and those restored with ﬂowable mate-rial (Grandio Flow, VOCO). A more recent study by Sumino et al37 indicated that the ﬂowable (injectable) materials G-aenial Universal Flo (GC America), G-aenial Flo (GC Amer-ica), and Clearﬁl Majesty Flow (Kuraray Noritake) had signiﬁcantly greater ﬂexural strength and a higher elastic modulus than the corresponding conventional nanocom-posite materials, Kalore (GC America) and Clearﬁl Majesty Esthetic (Kuraray Noritake). The wear and mechanical properties of these speciﬁc universal injectable resin com-posites suggested an improved clinical performance com-pared with that of the universal composites.Fig 4 Upon completion of the adhesive protocol, the clear silicone matrix was placed over the arch and an opacious shade A2 ﬂowable resin composite (G-aenial Universal Flo, GC America) was initially injected through a small opening above each tooth, followed by mixing with a shade B1 ﬂowable resin composite (inverse injection layering technique). The resin composite was cured through the clear resin matrix for 40 seconds.Fig 5 Completed composite veneer restorations with optimal anatomical form. The inverse injection layering technique allowed the establishment of harmonious proportions of the transitional restorations and the surrounding biologic framework.54 TERRY ET ALQDT 2020244Several in vitro studies conducted at GC Research and Development comparing speciﬁc ﬂowable material proper-ties of several conventional composites found results simi-lar to those of Sumino et al. Of the next-generation ﬂowable systems studied, G-aenial Universal Flo (GC America) and Clearﬁl Majesty ES Flow (Kuraray Noritake) showed supe-rior gloss retention and similar wear resistance to the con-ventional nanocomposites tested, which included Filtek Supreme Ultra (3M ESPE), Herculite Ultra (Kerr), Clearﬁl Majesty ES-2 (Kuraray Noritake), and G-aenial Sculpt (GC America).According to these studies, the recently developed spe-ciﬁc nanohybrid ﬂowable resin (or universal injectable) composite systems (ie, Clearﬁl Majesty ES Flow and G-aenial Universal Flo) may possess properties that meet the aforementioned mechanical, physical, and optical requi-sites. These properties and the clinical behavior of the bio-material formulations are contingent on their structure. New resin ﬁller technology allows higher ﬁller loading be-cause of the surface treatment of the particles and the in-crease in the distribution of particle sizes. The unique resin ﬁller matrix allows the particles to be situated very closely to each other, and this reduced interparticle spacing and homogeneous dispersion of the particles in the resin ma-trix increases the reinforcement and protects the ma-trix.41–43 In addition, the proprietary chemical treatment of the ﬁller particles allows proper wettability of the ﬁller sur-face by the monomer and thus an improved dispersion and a stable and stronger bond between the ﬁller and resin.Studies43–47 clearly indicate the importance that ﬁller con-tent and coupling agents represent in determining charac-teristics such as strength and wear resistance. Recent studies19,31,48 report that ﬂowable (universal injectable) composites have comparable shrinkage stress to conven-tional composites. According to the manufacturers, these next-generation ﬂowable (universal injectable) composite formulations are purported to offer mechanical, physical, and esthetic properties similar to or better than those of many universal composites.49 The clinical attributes of uni-versal ﬂowable composites include easier insertion and manipulation, improved adaptation to the internal cavity wall,50 increased wear resistance, greater elasticity, color stability, enhanced polishability and retention of polish, and radiopacity similar to enamel. Furthermore, the clinical indi-cations for these next-generation ﬂowable resin compos-ites are increasing as the properties of the materials and the bond strength of adhesives to dental tissues improve. With improved mechanical properties reported,37 these highly ﬁlled formulations are indicated for use in anterior and posterior restorative applications.5 The clinical applica-tions of these speciﬁc next-generation universal injectable composites include sealants and preventative resin resto-rations; emergency repair of fractured teeth and restora-tions; fabrication, modiﬁcation, and repair of composite prototypes and provisional restorations4; anterior and pos-terior composite restorations; composite tooth splinting51; and intraoral repair of fractured ceramic and composite restorations.51 In addition, these composites can be used to repair denture teeth,51 establish vertical dimension, alter occlusal schemes before deﬁnitive restoration,5 manage spatial parameters during orthodontic treatment, eliminate cervical sensitivity,51 resurface occlusal wear on posterior composite restorations,51 establish incisal edge length be-fore esthetic crown lengthening,51 develop composite pro-totypes for copy milling,5 and place pediatric composite crowns.6Since the past provides information to improve the fu-ture, the lack of evidence-based research and clinical trial data on ﬂowable biomaterials requires clinicians to evalu-ate the individual mechanical properties of these materials to determine whether their properties are equal or superior to those of existing materials. As the clinical performance of these next-generation ﬂowable materials has improved over time, the research data have concurred. Although no direct correlation has been found between a material’s me-chanical and physical properties and its clinical perfor-mance, such a correlation might suggest the potential success of a restorative biomaterial for a speciﬁc clinical situation.16 However, clinical longevity for restorations de-veloped with these biomaterials remains to be determined through clinical studies for each speciﬁc clinical application.Future clinical applications of this novel technique with these next-generation ﬂowable materials may provide cli-nicians and technicians with alternative approaches to various clinical situations while allowing them to deliver im-proved and predictable dental treatment to their patients. Although the long-term beneﬁts of this novel injectable composite technique remain to be determined, the clinical results achieved by the ﬁrst author in the last 12 years and the aforementioned supporting empirical data for these next-generation nanocomposite ﬂowables are extremely promising. Cases 1 to 5 illustrate some of the many clinical applications of the injectable resin composite technique using various highly ﬁlled formulations of ﬂowable com-posite materials (Figs 6 to 41).