Question: “To Crown or Not to Crown”. This case gives us food for thought before we reach for the easy solution. Read on…
Voco Grandio SO: Combined User Report/Testimonial: Posterior case
“An Optical and Structural Tooth Mimetic”
There is no single key to stress-free esthetics in restorative dentistry today. Indeed, the ingredients leading to the perfect direct composite result are multivariate and may depend to some degree on your artistic tendencies that day. It is no secret that the sine qua non of cosmetic and restorative dentistry is predictability. Predictable restorative materials embody the hallmarks of chameleon effect, ease-of-polishability, biomimetic physical properties, ideal texture and handling, minimal polymerization shrinkage, superior wear resistance and good radio-opacity. Basically, the more the material works and the less you have to, the better. Prior to this point, one turned to bonded porcelain restorations for strength and durability. Voco Grandio SO is a cutting-edge techno-nanohybrid representing a paradigm shift where direct composite restorations can be placed with such ease, physical and esthetic predictability that you will find yourself reaching for it time and again.
Clinical Case Background
Fig. 1. An 89 year-old female patient presented to my service for a routine minor restorative procedure: recurrent deep cervical caries underneath an old amalgam restoration on tooth 24MODB (FDI classification). After clinical and radiographic analysis of vitality as well as assessment of residual tooth structure, it was ascertained that such a polychromatic tooth featuring extensive pulpal sclerosis would be best-restored with a direct bonded composite resin restoration due to the need to preserve maximal residual tooth structure, which may be lessened should an indirect bonded porcelain inlay be selected due to the need to establish draw of the walls. The following criteria were examined before deciding that Voco Grandio SO would be the astute solution to this compromised situation.
Biomimicry of a material is the next best thing to actually reproducing natural enamel and dentin for a restoration. Prior to this point, the numerous resin composites I had previously tested featured numerous struggles in compromise. On one hand, a product may be really optically-perfect, but a nightmare to handle. It may not stick to your instrument, but it may not stick to anything. It might be a pleasure to butter and shape, but lack chameleon effect and radio-opacity. In the development of Grandio SO, Voco has strived to exactly reproduce the optical and physical parameters of natural tooth structure, allowing any direct restoration to restore the original strength of the tooth long-term.
Grandio SO represents the culmination of years of collaboration in research that has produced a composite resin with a strikingly-high filler weight percentage of 89% (w/w). Correspondingly, a high filler percentage equates with low linear polymerization shrinkage, previously one of the main struggles of other composite systems. As recurrent caries is the Number 1 stated reason for clinical failure, his feature allows for maintained marginal integrity and optimal long-term success.
Other companies have attempted to achieve low linear polymerization shrinkage by using different techniques, such as the opening of monomer ring configurations during polymerization (i.e. silorane, oxyrane and spiro-orthocarbonate). However, these monomers cannot use conventional bonding agents, since they set via cationic polymerization, as opposed to conventional materials, which use radical polymerization. There is also the obvious disadvantage of committing yourself to a new armamentarium for bonding and their respective product lines.
Elastic Modulus and Thermal Behaviour
Voco has utilized two main ingredients that lend strength to Grandio SO. They have incorporated glass ceramics in a bed of resin featuring 60% functionalized nanoparticles (20-40nm). Strength is integral in the design of a composite as restorative materials will be subjected to the same dynamic and damaging cyclical loads as natural tooth structure. Lending stiffness back to the tooth as well as minimally-disturbing residual tooth structure must be an uncompromised quality. Grandio SO thus is actually the most tooth-like direct composite material available, boasting an elastic modulus over 16.55 GPa (dentin range: 16.55 to 18.62); significantly greater above any other composite material. Likewise, thermal loading figures are equally impressive when compared against the competitor range, showing significant absolute minimal dimensional change within a 5mm diameter lesion and an 11 degree Celsius variation. This is important to prevent cyclical thermal flexure and fatigue of residual tooth structure, a feature which would in its absence accelerate its demise.
Bonding Technique Evaluation
Voco’s Futurabond NR represents exactly that. The future of bonding agents. I am an avid 4th and 5th generation total-etch bonder. However, the numbers for Futurobond NR forces one to have another look. The dentine shear bond strength of Futurobond NR was found to be higher than any other new-generation self-etching bonding agent , exceeding 30MPa. The reference shear bond strength that I use is Kerr Optibond Solo Plus, which is referenced at 31.3MPa. This is a close comparison in dentin adhesion values. What about enamel? Enamel bond strengths were found to be optimized utilizing a separate etching technique as per (Luhrs et al, 2008), and exceeded 35MPa for Futurabond NR. Thus, an enamel-pre-etching step was used for 20 seconds prior to drying to a moist dentin stage, followed by application of the ethanol-based Futurabond NR.
Surface Invincibility – Composite Posing as Porcelain? Looking like tooth.
The reasons behind the outstanding surface longevity of Voco Grandio SO are multifactorial. Firstly, Grandio SO boasts a Vickers Micro-Hardness reading in excess of 200MHV that significantly is more than two-fold greater than any other tested composite material and approaches that of human enamel (350-450MHV). This is significant in the resistance form and feature of any restoration, and is invaluable for marginal resistance to wear and leakage. Indeed, the combination of surface hardness, naturomimetic coefficient of thermal expansion and high filler content make this the most “porcelain-like” composite restorative on the market. In other words, the clinical performance of Voco Grandio SO appears to migrate towards that of bonded porcelain. Despite its extreme surface hardness, the chemical engineers at Voco have managed to also give it the gift of extreme polishability, which again decreases surface wear and brings a smile to our faces. A three-way comparison between Grandio SO, Tetric EvoCeram and Venus Diamond, a University of Dublin study (Dr. G. Fleming, University of Dublin, 2010, data on file) demonstrated a significantly lower surface roughness figure for Grandio SO in the 5.5 to 8.5micrometer reading, unmatched by the other materials. This extreme polishability was evolved from Voco Amaris, and paired with the extreme surface hardness of this unique nano-hybrid equates to a material that will keep shining long after all the other composite materials have worn and faded.
Guts and Glory: Creep, Compressive Strength and Tensile Strength
One of the main factors that biased my attention to using Grandio SO in all posterior bonded restorative applications was its compressive strength. At 439MPa, it is significant. It is significant because it is the only composite material tested to date that actually exceeds the compressive strength of my preferred indirect bonded porcelain material: IPS e-max (Amherst, NY), which boasts a compressive strength of 400MPa in pressable form. In this regard, it behaves like porcelain, an enviable characteristic for any composite. Why is this important? As teeth are subjected to intermittent and static loads, compression results in elastic and also a degree of inelastic deformation. This is important for the durability of posterior restorations because inelastic deformation or “permanent set” will destroy your marginal integrity and marginal bond. Stress under tension is usually the Achilles heel of any material. Grandio SO features a tensile strength value of 72MPa, nearly twice that of natural dentin, and head-and-shoulders above the competition. Say no more. Predictable success lies with the product featuring bondability with the highest compressive and tensile strength possible: Voco Grandio SO certainly has the guts.
Stress-Free Esthetics: Meet the Chameleon
Sculpting direct composite beauty is hard enough. Voco has engineered Grandio SO to recognize this by allowing simplicity of not only placement, but also shade selection. Due to the unique optical properties of Grandio SO, often, only a main single shade is required for a completely invisible restoration. If you feel like being ultra-creative and mixing shades, you don’t have to. Voco have created two unique shades: A3.25 and A5. In the case shown, A5 was utilized for the cervical aspect of the MODB subgingival lesion, and A3.25 was used for the entire coronal aspect. Polishability is unmistakably exceptional.
Simplicity in esthetics, fortitude in predictability, and pleasure in placement make Voco Grandio SO perhaps the single key to predictable esthetics in restorative dentistry today.
Fig. 2. Oblique MB view intraoperative photo showing subgingival preparation 24MODB devoid of amalgam and caries.
Fig. 3. Occlusal view of tooth 24MODB preparation.
Fig. 4. Dual Triodent V3 rings securing matrices.
Fig. 5. Voco Futurabond NR self-etch bond (I like to pre-etch the enamel prior to using this). Dentin bond strengths are incredible.
Fig. 6. Voco Futurabond NR being applied to the preparation.
Fig. 7. Finished mesiobuccal oblique view of restoration 24MODB. Dehydration of natural tooth structure evident.
Fig. 8. Pre-finished restoration. Shades used: A5 was utilized for the cervical aspect of the MODB subgingival lesion, and A3.25 was used for the entire coronal aspect.
Fig. 9. Polished restoration.
Fig. 10. Immediate post-operative radiograph showing excellent radioopacity of Grandio SO on tooth 24MODB and precise adaptation to margins.