Unavoidable Dentine Bonding

A clinical case by our Community member Dr Edward Li

This article and its content are published under the Author’s responsibility as an expression of the Author’s own ideas and practice. Styleitaliano denies any responsibility about the visual and written content of this work.

The evolution of dentine bonding has transformed modern dentistry, prioritizing durable and aesthetically pleasing restorations. However, replacing past restorations like old crowns and veneers often presents challenges, particularly when enamel is significantly reduced. LuxaBond Universal addresses these challenges with its advanced formulation, offering superior bonding strength and compatibility with various substrates, including dentine with diminished enamel. It represents the pinnacle of dentine bonding evolution, ensuring reliable and long-lasting restorations even in scenarios where enamel is limited.

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Fig.1
The patient sought to align the appearance of the lower teeth and reduce the prominence of the upper anterior teeth.
The teeth presented on a Skeletal II base with a mild Class II division 1 incisal relationship.
Upper left central incisor had an overbulbous veneer that the patient really wanted to change. Heading into treatment, I recognized the crucial importance of dependable dentine bonding, while also aiming to preserve as much of the enamel “bio-rim” or circumference as possible during the removal and preparation of the upper left central incisor.
The treatment plan involves preparing the foundation for the restorative phase, with orthodontic alignment taking precedence initially.

styleitaliano style italiano close up of teeth after orthodontic alignment

Fig.2
Post alignment the patient was prescribed home whitening to improve the overall shade of the teeth and elevate the brightness.

styleitaliano style italiano intraoral scan superimposition before and after alignment

Fig.3
The merged scans of both pre and post ortho to objectively see the degree of labial retraction achieved and lower anterior alignment.

styleitaliano style italiano shade matching

Fig.4
Prior to proceeding with the restorative appointment, the teeth colour was reviewed after whitening, taking care to assess it before any dehydration occurred. The teeth are compared to the closest matching e.max shade, which predominantly fell under MT BL4 with highlights of MT BL3, disregarding the existing restoration on the UL1.

styleitaliano style italiano direct mock up

Fig.5
When observing and deciding what is necessary restoratively, we first need to envision what is possible.
For simpler cases a smile design isn’t always needed, however it may be wise if you wish to communicate to the patient more accurately and do a trial.
In this scenario, the goal is to minimise the prominence of the upper central teeth while achieving a balanced silhouette and proportion for the lateral and canine teeth to complement each other. However, achieving this balance is challenging without making irreversible changes. One method is to use a pencil or wipeable marker to colour in the edges, simulating the visual silhouette of smaller and shorter teeth. However, since restorative treatment was planned for these teeth, a subtle enamel adjustment was performed using a fine diamond and sof-lex discs on the upper right central incisor, and the upper left central incisor veneer was adjusted to match. This approach proved to be the most effective way to communicate and visualise the desired length for the replacement veneer. The first veneer fell short of expectations due to its excessive bulbosity and contrasting anatomy compared to the natural teeth. Additionally, it displayed a red/brown hue in the mid-body and cervical portion, prompting the anticipation of a highly chromatic base. Fortunately, the radiograph and assessment revealed no metal (and thus no grey/black) to conceal, presenting a different challenge altogether.

styleitaliano style italiano dehydrated vs hydrated substrate

Fig.6
This photo is to highlight and share the difference in perceived chroma when a substrate is dry and wet. With all accurate shade taking, please take into account when a substrate is dry (image on the left), its chroma is masked by the matte nature of the surface. When applying water or glycerin to its surface (image on the right), the chroma reveals itself. It is the same for when trying a lobe of composite for shade matching or even doing a ‘dry’ fit of the veneers, don’t do it dry, use water or glycerin at least to replicate a total transparent ‘cement’ to help visualise and decide whether the bonding composite needs to influence the result.

styleitaliano style italiano substrate shade matching

Fig.7
The closest Vita Classic is A4 but the true information shared in this photo for my ceramist is that the substrate has an orange chroma more intense than A4 and to show where it is concentrated.
I prepped to give ~1.5mm at the cervical and ~1.2mm where the incisal edge finishes. The incisal height was dictated by the original veneer which is quite a lot heavier than ideal, but it does lend to lots of room for my ceramist to use a high opacity e.max (LT) to tackle the substrate and layer the highly aesthetic porcelain to break up the light.
Precision care under magnification is used to prep subgingivally without traumatising the soft tissue to allow a 2-stage PVS to be taken on the day of prep to fabricate the final restoration without an additional phase of soft tissue conditioning that is sometimes needed.

styleitaliano style italiano ceramic veneer

Fig.8
The final ceramic veneer. Here we are assessing the anatomy created, its colour, silhouette, reflections and surface details.

styleitaliano style italiano situation before veneer fitting

Fig.9
On the day of fitting, considerations such as the health of the gums, presence of stippling, absence of damage during temporary removal, and the delicate balance between moisture control and maintaining gum health and profile are crucial aspects to be carefully managed. It is not always appropriate or necessary to use complete isolation with rubber dam but a form of isolation whether is is split dam or as in the photo “optragate” is.

styleitaliano style italiano DMG luxabond universal

Fig.10
The inclusion of the MDP monomer within LuxaBond Universal facilitates a robust chemical bond among all components. In this case we needed something extremely reliable to use on the dentine surface of the tooth, but also a bond that is dual cured so that we could cement the veneer without needing to light cure first.
Bonding using DMG Vitique BL with the ergonomic broad nozzle aiding application and reduction in the use of microbrushes and introducing air bubbles or contaminants. Porcelain is sandblasted, etched and silanated. LuxaBond Universal is applied to the fit surface of the veneer and air-dried. The tooth is etched, rinsed with water and LuxaBond Universal is applied. Due to the dual cure properties of LuxaBond Universal it can be left un-cured for seating of the veneer. The veneer is seated and checked for correct alignment and position. Excess cement is cleaned off using a combination of fine microbrushes and then tac cured. A sickle scaler or LM excess can be used to remove additional cement before the veneer is cured fully once again. The gingival margins are inspected with a probe and interproximal contacts are flossed to ensure no cement remains.

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styleitaliano style italiano before and after rehydration and gum healing

Fig.11
Top image: Immediate Post Op.
Lower image: Rehydrated and gum health achieved a few weeks later.

styleitaliano style italiano polarized picture after cementation

Fig.12
Cross Polarised view to reveal the opacity of the BL2 LT base and its high value, but its softened appearance from the mesial distal and incisal translucency and internal textures.
It should be noted that we added composite (Ecosite Elements Layer BL) to the upper left canine and lateral incisor, and to the upper right central and lateral incisor and canine to complete the makeover. The composites blend in seamlessly onto the natural teeth and compete with the ceramic veneer.

styleitaliano style italiano final result after veneer makeover veneer restoration

Fig.13
The final smile view. The patient is extremely happy with the outcome.

styleitaliano style italiano before and after veneer makeover veneer restoration

Fig.14
The ultimate outcome reveals a retracted upper labial segment with significantly reduced prominence on the Skeletal II base. Achieving a balanced integration, the appearance closely resembles Skeletal I, exhibiting a Class I incisal appearance.
Upper Image: Pre op Right and Left Lateral views.
Lower Image: Post op Right and Left Lateral views.

Conclusions

When we have reliable materials and predictable workflows we can achieve great results that are long lasting. The advantages of using LuxaBond Universal can be summarised below.

LuxaBond Universal serves dual roles as an adhesive and primer:

  1. As an adhesive, it can be applied for various procedures including direct restorations with light-curing composites as seen in the case above, and for cementing and for bonding veneers.
  2. As a primer, LuxaBond Universal is compatible with indirect silicate ceramics.

The versatility and multi-use properties make LuxaBond Universal a perfect choice.

Bibliography

  1. Sofan E, Sofan A, Palaia G, Tenore G, Romeo U, Migliau G. “Classification review of dental adhesive systems: from the IV generation to the universal type.” Ann Stomatol (Roma). 2017 Jul 3;8(1):1-17.
  2. Kosan E, Prates-Soares A, Blunck U, Neumann K, Bitter K. “Root canal pre-treatment and adhesive system affect bond strength durability of fiber posts ex vivo.” Clin Oral Investig. 2021 Nov;25(11):6419-6434.
  3. Khudhur HA, Bakr DK, Saleem SS, Mahdi SF. “Evaluating shear bond strength efficacy of seventh and eighth generation bonding agents (an in vitro study).”

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