Politano, Gianfranco

The importance of the interdental anatomy of a class-2 direct composite restoration is one of the most underestimated topics in direct posterior composite restorations. The proximal emergence profile of the restoration and the contact area should be designed to maximize arch continuity and to minimize food impaction. Other restorative criteria that must be fulfilled are marginal adaptation compatible with the dental and periodontal integrity, and geometry of the marginal ridge compatible with the mechanical integrity of the restoration under load. Shortcomings will result in masticatory discomfort, caries, periodontal problems and undesired movement of teeth. In vitro and in vivo studies showed that the use a contoured sectional metal matrix band with a separation clamp results in the tightest contact point. However, this matrix system also has shortcomings and does not give the expected result in all class-2 cavities. The variation in depth, width of the box, distance between the cervical cavity margin and the adjacent tooth requires customization of the interproximal space. In order to realize this, sectional matrix bands with several profiles of curvature, variation of wedges and separation clamps, and the use of teflon tape are required. In addition, dentists should follow a protocol allowing them to build a proximal composite surface that fulfills the required restorative criteria. Pre-wedging, space evaluation, interproximal clearance, correct selection, positioning and stabilization of the matrix band are important steps in this protocol. Schlagwörter: class-2, composite resin restoration, matrix system, proximal contact point, proximal emergence profile

Abstract: Tooth-cavity preparation contributes to a large extent to the quality of the direct posterior composite restoration, the so-called hidden quality of the restoration. Indeed, the effect of a poor cavity design is not immediately visible after placement of the restoration. To correctly prepare a cavity for a posterior composite restoration, the tooth to be restored should first be profoundly biomechanically analyzed. Here, the forces that work on the tooth during occlusion and articulation, and the amount and quality of the remaining tooth structure determine the cavity form. In addition, the dental tissues must be prepared in order to receive the best possible bond of the adhesive and subsequent restorative composite. A well-finished cavity preparation enables the restorative composite to adapt well, providing a good marginal ?seal to the direct benefit of the clinical lifetime of the posterior composite restoration. Finally, it is highly recommendable to isolate the teeth with rubber-dam before starting with the cavity preparation, as this increases the visibility of the operating field and allows the operator to work in a more precise way.

Abstract: Currently, there is a trend towards simplification of materials and clinical procedures. Simplification and quality can go together if the dentist works with materials and techniques that are well proven in vitro and in vivo. The placement of a high-quality class-1/2 direct posterior composite restoration can be time efficient following a standardized layering protocol and using composite materials that adapt well to the tooth surface and are able to mimic the natural tooth. When these materials are applied in a controlled way, finishing and polishing can also be shortened. In this article, an effective layering and finishing/polishing protocol for medium-sized class-1/2 direct posterior composite restorations is presented. Following the histo-anatomic buildup of natural teeth, dentin must be concave, as opposed to convex enamel. An isochromatic, medium-opaque, highly filled flowable composite is used to replace dentin. Enamel is replaced with a medium-translucent small-particle hybrid composite. Enamel is modelled in an anatomical way, following a successive cusp-by-cusp buildup approach. Clinical experience shows that the combination of both materials used according to this so-called bi-laminar histo-anatomical layering approach results in restorations that blend in very well within the surrounding tooth structure. Following a simplified finishing and polishing protocol, the composite restorations will have a correct contour, seamless margins, and a smooth, glossy surface. Schlagwörter: adhesion, finishing, flowable, layering, polishing, polymerization, posterior composite, shrinkage

Nichtkariöse zervikale Läsionen (NKZL) sind Hartgewebsverluste in der Zervikalregion von Zähnen aufgrund nichtkariöser Prozesse. Da sich Lebensweise und Ernährung der Menschen deutlich gewandelt haben, sind NKZL heute ein häufiges pathologisches Bild. Die Prävalenz und Schwere der zervikalen Abnutzung wachsen mit dem Alter. Allgemein wird davon ausgegangen, dass NKZL nicht durch einen einzelnen, sondern durch eine Kombination von Faktoren entstehen. Im Zusammenhang mit der Entstehung und Progression keilförmiger Defekte stehen Biokorrosion (Erosion), Friktion (Abrasion) und möglicherweise okklusale Belastung (Abfraktion). Das klinische Erscheinungsbild variiert je nach der Art und Schwere der beteiligten ätiologischen Faktoren. Der Zahnarzt sollte eine Checkliste verwenden, um zu einer exakten Diagnose der Ätiologie multifaktorieller NKZL zu gelangen. Die erfolgreiche Prävention und Behandlung von NKZL setzt ein Verständnis der Ätiologie und Risikofaktoren sowie der Art und Weise ihrer zeitlichen Veränderung beim einzelnen Patienten voraus. Ob NKZL beobachtet oder behandelt werden, sollte aufgrund der Progression der Läsion und ihrer Bedeutung für die Vitalität, Funktion und Ästhetik des Zahns entschieden werden. Eine Behandlung ist möglich mit Techniken zur Linderung der Dentinüberempfindlichkeit sowie mit adhäsiven Restaurationen, ggf. in Kombination mit einer chirurgischen Wurzeldeckung. Adhäsive Restaurationen gelten als letzte Therapieoption für NKZL. Aufgrund ihrer hervorragenden ästhetischen Eigenschaften und guten klinischen Bewährung ist die Behandlung von NKZL mit Kompositrestaurationen allgemein indiziert. Die klinische Bewährung dieser Restaurationen ist stark produktabhängig, insbesondere was das verwendete Adhäsivsystem anbelangt. Dagegen scheint der Komposittyp in klinischen Studien keinen signifikanten Einfluss auf die klinische Bewährung der Restaurationen für NKZL zu haben. Viel wichtiger ist die korrekte klinische Ausführung durch den Behandler. Während der Alterung ist häufig ein Nachlassen der Randgüte zu beobachten. Jährliche Pflege mit einer Nachpolitur der Restaurationsränder, falls erforderlich, erhöht die Lebensdauer der Restaurationen.

Noncarious cervical lesions (NCCLs) involve the loss of hard tissue from the cervical areas of teeth through processes unrelated to caries. NCCLs are nowadays a common pathology caused by changes in lifestyle and diet. The prevalence and severity of cervical wear increase with age. It is generally accepted that the lesions are not generated by a single factor but result from a combination of factors. Among the factors proposed to be related to the formation and progression of NCCLs are biocorrosion (erosion), friction (abrasion), and possibly occlusal stress (abfraction). The clinical appearance of NCCLs can vary depending on the type and severity of the etiologic factors involved. Practitioners should follow a checklist to achieve an accurate diagnosis of the etiology of multifactorial NCCLs. The successful prevention and management of NCCLs require an understanding of the etiology and risk factors, including how these change over time in individual patients. The decision to monitor NCCLs rather than intervene should be based on the progression of the lesions and how they compromise tooth vitality, function, and esthetics. Treatment options include techniques to alleviate dentin hypersensitivity and the placement of an adhesive restoration, eventually in combination with a root coverage surgical procedure. An adhesive restoration is considered the last treatment option for NCCLs. Based on their excellent esthetic properties and good clinical performance, there is a general indication to place composite restorations for NCCLs. The clinical performance of these restorations is highly product-dependent, particularly regarding the adhesive system used. The type of composite material seems to have no significant influence on the clinical performance of NCCL restorations in clinical trials. It is much more important that the operator carries out the clinical procedure correctly. Marginal degradation is frequently seen during aging. Yearly maintenance with the eventual repolishing of the restoration margins will lengthen the lifespan of the restorations.

Purpose: Adhesively luted partial ceramic crowns have been documented to be clinically more durable than direct composite restorations when minimally invasively restoring large defects (replacing two cusps or more) in posterior teeth. The clinical longevity of such restorations is largely determined by the tooth-preparation design, material selection and adhesive luting procedure. The most frequently recorded failure in medium- to long-term clinical trials is fracture of the restoration. The clinical protocol of adhesively luted partial ceramic crowns can be optimized by taking the etiology of these restoration fractures into account. In this article, a simplified nonretentive bonded ceramic partial crown concept is presented that aims to achieve an adhesively luted ceramic restoration - composite cement - residual tooth structure biomechanical unit that maximally resists functional aging. Therefore, the three primary components of the bonded restoration-cement-tooth complex must function in synergy. Methods, Results and Discussion: The clinical protocol starts with a tooth preparation designed to optimally absorb chewing stress. A stable, internally rounded and gently sloping tooth-preparation design with all outer margins inclined towards the tooth center assures a favorable and homogenous stress distribution with low cyclic fatigue subjected to the adhesive interface. This preparation form additionally enables the dental technician to fabricate a well-seating and -fitting ceramic restoration of uniform thickness. As restoration material, monolithic lithium-disilicate glass ceramic is sufficiently strong for the partial crown indication and preferred in order to decrease the fracture risk. Clinically essential for a long-lasting restoration is the optimal bond that can be obtained by combined micromechanical interlocking and chemical bonding of composite cement to hydrofluoric acid-etched and silanized glass ceramic. Conclusion: The clinical effectiveness of this nonretentive bonded ceramic partial crown concept is confirmed by the overall high success rate as well as the very low fracture and debonding rate, as was recorded in long-term clinical trials. Schlagwörter: overlay, onlay, tooth preparation, glass ceramic, indirect restoration

Restorative procedures are accompanied by a reduction of tooth stability, a decrease of fracture resistance, and an increase in deflection of weakened cusps. The choice between a direct or an indirect restorative technique, mainly in posterior areas, is a challenge, and involves biomechanical, anatomical, functional, esthetic, and financial considerations. In this article, the pros and cons of direct restorations are examined, as well as an analysis of indirect restorations and an overview of dental ceramics. In particular, several clinical uses of lithium disilicate overlays with a circumferential adhesive ferrule effect are proposed: heavily compromised vital teeth with thin walls, cracked teeth, and endodontically treated molars. Clinical procedures are described step by step on the basis of data from scientific literature. In conclusion, the use of lithium disilicate in combination with adhesive technologies can lead to a more conservative, economic, and esthetic approach in the restoration of heavily compromised teeth.

Restaurative Eingriffe können zur Schwächung der Zahnstabilität, Abnahme der Bruchfestigkeit und Zunahme der Verformung geschwächter Höcker führen. Die Wahl zwischen direkten und indirekten Restaurationen ist besonders im Seitenzahnbereich nicht unproblematisch und erfordert Überlegungen zur Biomechanik, Anatomie, Funktion, Ästhetik und den Kosten. In diesem Artikel werden die Argumente für und gegen direkte Restaurationen untersucht sowie eine Analyse indirekter Restaurationen und ein Überblick über Dentalkeramiken geboten. Verschiedene klinische Indikationen für Lithiumdisilikat-Overlays mit zirkumferenter adhäsiver Umfassung (Ferrule) werden genannt: stark zerstörte vitale Zähne mit dünnen Wänden, frakturierte Zähne und wurzelbehandelte Molaren. Der Behandlungsablauf wird Schritt für Schritt und auf Basis der Daten aus der Literatur beschrieben. Die Verwendung von Lithiumdisilikat in Kombination mit Adhäsivtechniken kann ein eher konservativer, ökonomischer und ästhetischer Ansatz für die Restauration stark zerstörter Zähne sein.

Anhand des Patientenfalls einer Patientin mit insuffizienten Kompositversorgungen im Frontzahnbereich und einem ausgeprägten Zahnfleischlächeln stellen die Autoren ihre Versorgungsphilosophie vor. Diese stellt mit dem Ziel, das bestmögliche Ergebnis zu erreichen, den größtmöglichen Erhalt an Zahnsubstanz und den Patientenwillen in den Vordergrund. Dies nur mithilfe einer optimalen interdisziplinären Planung unter vollständiger Einbindung des Patienten möglich. Schlagwörter: Ästhetik, ästhetische Analyse, Teamarbeit, Wax-up, Mock-up, minimalinvasive ästhetische Zahnmedizin, Veneers