Simplifying indirect restorations with dual-cured dentine substitutes

A clinical case by our Community member Dr Fahad Taub

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.

Procedures for adhesive indirect restorations are still to be collectively standardized, as there are various ways in which clinicians can prepare for them. The conundrum arises from the use of a wide variety of indirect materials, preparation protocols, dentine substitutes, and cementation procedures.

One way to simplify indirect restorations is through the use of a dentine substitute. These can range from resin-modified glass-ionomer to light-cured composites and dual-cure composites. The advantages are apparent in that they can prevent surgical crown lengthening by enabling deep margin elevation (provided there is sufficient space left for biologic width formation between the cavity floor and the alveolar bone). Additionally, they allow clinicians to prepare the tooth to its final form, which can provide a better understanding of the taper of their preparation. They also enable the clinician to visualize potential undercuts and the final pathway of insertion for the restoration.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes x-ray showing decay on upper teeth

Fig.1
A 40-year-old female attended a new patient examination. Radiographic imaging revealed a leaking distal composite restoration on tooth 15, with decay evident on the mesial surface. Additionally, decay was observed on the distal surface of tooth 14. It was also noted that tooth 16 had a large composite restoration with a suboptimal interproximal contact point. This diagnosis was made solely based on radiographic evidence, as the patient was asymptomatic and showed no superficial signs of decay. Furthermore, teeth 16, 15, and 14 all responded positively to cold testing, with no adverse recovery times.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes before caries removal

Fig.2
An occlusal view of the initial situation.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes prewedging before caries removal

Fig.3
Rubber dam isolation was performed, and the teeth were pre-wedged to protect the rubber dam during cavity preparation.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes cavity preparation

Fig.4
The cavities on teeth 15 and 14 were prepared and excavated using diamond burs, with the aid of a caries detector.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes caries detector

Fig.5
With the aid of the caries detector, it was evident that the distal portion of tooth 15 was heavily affected by decay. Consequently, greater tooth removal was required in this area to ensure that the dentinoenamel junction (DEJ) was completely clear of caries-infected dentine.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes cavity with circumferential matrix for deep buildup

Fig.6
Once the DEJ was clear of any infected dentine, it was observed that the distal margin of tooth 15 was very deep. To aid in creating a proximal seal in this area, a sectional matrix was placed within the circumferential matrix. This technique allows clinicians to achieve a homogenous seal in the most apical portions of dental cavities, thereby enabling the margin to be elevated.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes air abrasion of cavity

Fig.7
Air abrasion was then carried out with 29μm aluminum oxide using the Aquacare system. This step was vital for removing any remnants of infected dentine and improving the overall bond strength of the dentine substitute to the remaining tooth structure.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes selective enamel etching

Fig.8
Due to the depth of the cavity on tooth 15 and its proximity to the dental pulp, a selective etching bonding protocol was utilized to prevent any irritation to the dental pulp complex. Therefore, 37% orthophosphoric acid was applied to the enamel of teeth 15 and 14 (selective enamel etching) for approximately 30 seconds before being rinsed and thoroughly dried.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes bonding by dmg

Fig.9
As part of the bonding process, LuxaBond Universal was dispensed and mixed in a 1:1 ratio before being applied to the cavities of teeth 15 and 14.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes bonding and build up of cavity

Fig.10
The LuxaBond Universal bond was applied to the teeth, and the dentine was scrubbed for 20 seconds. Any pooling of the adhesive was removed using a clean microbrush. Subsequently, with a steady stream of air, the adhesive was dried for 10 seconds to remove any solvent. The adhesive was then light-cured for 20 seconds.
The proximal wall of tooth 14 was built up using shade A2 Ecosite Elements with a sectional matrix.
Furthermore, LuxaCore Z Dual was dispensed into the cavity of tooth 15 using the provided intra-oral tip. This allowed for the material to be dispensed in a controlled manner deep into the cavity. To prevent voids, it was fundamental that the tip remained submerged in the material until the cavity had been sufficiently filled. This was then cured for at least 20 seconds.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes build up with glycerine gel for final curing

Fig.11
Once the LuxaCore Z Dual had been cured, the disto-occlusal composite restoration was completed on tooth 14 using the aforementioned shade A2 Ecosite Elements. Both restorations were light-cured for 40 seconds before being light-cured again under glycerine for another 40 seconds.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes buildup before preparation

Fig.12
The glycerine was thoroughly rinsed, allowing for tooth 15 to be prepared for an indirect restoration.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes overlay preparation

Fig.13
As tooth 15 was visible in the smile line, a decision was made to extend the preparation so that the final restoration would cover and blend in with the buccal area of tooth 15. This was achieved using medium-grit and fine-grit diamond burs. Additionally, the proximal contact on tooth 16 was adjusted using a fine 3M Sof-Lex disc, as this contact point appeared too high on the initial radiograph.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes occlusal view of overlay preparation

Fig.14
It was observed that the transition between the LuxaCore Z Dual and the adjacent tooth structure showed no signs of voids or irregular concavities resulting from the preparation process. This was attributed to the material having a similar tactile hardness to that of dentine. Subsequently, the preparation was digitally scanned for the fabrication of a lithium disilicate restoration. This type of preparation was chosen for its conservative nature.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes surface treatment of lithium disilicate

Fig.15
After 10 days, the patient attended for the final fitting of the restoration. Tooth 15 was asymptomatic and ready for cementation of the final restoration. The restoration was treated with 9.5% hydrofluoric acid for 30 seconds before being rinsed. Any unwanted ‘chalky’ residue left by this etching process was cleaned using 37% orthophosphoric acid. Finally, the intaglio surface of the restoration was treated with silane and applied with a layer of LuxaBond Universal, which was air-dried and left uncured.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes cementation of disilicate overaly

Fig.16
Tooth 15 was air-abraded with 29μm Aluminum Oxide using the Aquacare system. The enamel was selectively etched with 37% orthophosphoric acid for 30 seconds and then rinsed. LuxaBond Universal was applied to the prepared tooth, scrubbed for 20 seconds, and then air-dried thoroughly for a further 10 seconds. The bond was left uncured (as it is dual-cure), and the restoration was cemented using a light-cured composite resin.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes view after overlay cementation

Fig.17
The margins of the restoration were then polished, and the rubber dam was removed. The patient’s occlusion was verified, and any interferences were removed without incident. It is worth informing the patient that the gingival tissues should settle with time.

style italiano styleitaliano indirect restorations with dual-cured dentine substitutes follow up of overlay restoration

Fig.18
The 4-month recall shows beautiful integration of both the overlay and composite filling, both occlusally and from the buccal view.

Conclusions

LuxaCore Z Dual has proven to be an excellent dentine substitute for core build-up prior to tooth preparation. Its dual-cured nature ensures adequate curing, even in deep defects greater than 4mm. Additionally, its tactile hardness facilitates smooth tooth preparation transitions. Finally, the material simplifies preparation design for all types of indirect restorations, whether conventional or adhesive.

Bibliography

  1. Magne, P and Spreafico R (2012). Deep Margin Elevation: A Paradigm Shift. The American Journal of Esthetic Dentistry, 2(2), 86-96.
  2. Fichera G, Mazzitelli C, Picciariello V, Maravic T, Josic U, Mazzoni A, Breschi L. Structurally compromised teeth. Part II: A novel approach to peripheral build up procedures. J Esthet Restor Dent. 2024 Jan;36(1):20-31.
  3. Koubi, S. (2022) Bringing up deep proximal margins. Simplifying everyday dentistry, StyleItaliano.
  4. D. Dietschi, R. Spreafico (1998) Current clinical concepts for adhesive cementation of toothcolored posterior restorations, Pract. Periodontics Aesthet. Dent. 10(1) 47–54.

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