Semi-Direct Overlay with Essential Lines

Treating heavily destroyed teeth is not always an easy task, we tend to remove all bad materials and tissues first and end up in a situation where we fail to see a proper solution. We lose standing walls, references for anatomical build-ups and situations which get tricky to isolate properly. This technique combines the Essential Lines Technique and the stamp technique to plan ahead before starting to excavate.

provisional GIC restoration style italiano styleitaliano

Fig.1
Initial situation, this tooth was referred back to me after the endodontic treatment. The coronal part is currently filled with Glass Ionomer and needs to be definitively restored. We already see this tooth has a peripheral rim fracture on the distal and the remaining walls look very thin. Keeping in mind the tooth had to be endodontically treated, we can expect the cavity to be quite large and possibly undermining the cusps, leading to even thinner walls. This patient also lacked financial independence, which made options such as an indirect overlay or a crown unavailable.

tooth with remaining thin cusps style italiano styleitaliano

Fig.2
Planning ahead, only 1,5-2 mm of the occlusal temporary filling was reduced to create space.

anatomy layered with essential lines style italiano styleitaliano

Fig.3
A one shot bulk layer was injected in the cavity without pretreating the tooth surface.
The Essential Lines technique was used to do a quick 3-5 minute anatomical build-up of the occlusal plane using remaining walls as a reference.

side view of composite occlusal anatomy style italiano styleitaliano

Fig.4
The Essential Lines technique allows to create functional and aesthetic anatomy in a very short time.

transparent silicone impression style italiano styleitaliano

Fig.5
A clear putty material was used to copy the planned anatomy. Be sure to have enough support of surrounding teeth to be able to reposition the stamp easily. Since this mould will be filled with heated packable composite.
After hardening of the silicone, I inserted the mould in my composite oven at 55° Celsius.

depth guide for cusp reduction style italiano styleitaliano

Fig.6
After complete removal of the temporary filling materials, further risk assessment of the tooth was done. All remaining walls were found too thin to be kept, and were thus reduced in height by 2 mm using standardized burs to produce depth cut grooves to ensure even anatomical reduction of the cusps.

single bur non retentive overlay preparation style italiano styleitaliano

Fig.7
Here it is shown what bur is used and how it was measured to use as calibrated depth cut bur. The same bur was also used to complete the preparation, thus limiting the need for multiple burs.

overlay preparation before build-up style italiano styleitaliano

Fig.8
After reducing of the cusps and walls, adequate thickness was achieved. A sectional matrix was placed to protect the neighboring tooth during sandblasting and bonding procedures.

sandblasted overlay preparation style italiano styleitaliano

Fig.9
Occlusal aspect of the tooth after sandblasting.

endodontic cavity filled with composite style italiano styleitaliano

Fig.10
Aspect after the final increment results in a non-retentive overlay preparation. Imagine having to build this up directly without any reference or height control left.

overlay with excess composite style italiano styleitaliano

Fig.11
The neighboring tooth was wrapped in PFTE tape to prevent composite from sticking to it. After filling up the heated transparent mould with heated Filtek Bulk Fill material, the uncured overlay was put back in the mouth and pressed into place. Holding the mould fixed, the composite is cured for about 5 seconds from each side, allowing to remove the stamp easily and removing excess composite with a no. 12 blade in the tight spaces.

semi-direct overlay after excess composite removal style italiano styleitaliano

Fig.12
Excess composite is removed with a slow speed diamond bur to finish all margins. Some stain was added to enhance the fissures.

side view of semi-direct overlay restoration style italiano styleitaliano

Fig.13
Final view of the anatomy created by following the original remainders of the tooth.

occlusal check of overlay restoration style italiano styleitaliano

Fig.14
Immediate occlusal check after rubber dam removal, no correction was needed.

composite overlay style italiano styleitaliano

Fig.15
3-month follow-up.

Conclusions

When facing large restorations, we often make the mistake of immediately removing all the references we have, forgetting we could use them to rebuild the tooth after removing all affected tissues. Planning ahead with the help of a fast, simplified technique for modelling the occlusal plane can help us save time and ease our lives. This also creates high quality restorations at low cost, which can help bringing better dentistry to more patients.

Bibliography

1. Chiodera G, Orsini G, Tosco V, Monterubbianesi R, Manauta J, Devoto W, Putignano A. Essential Lines: a simplified filling and modeling technique for direct posterior composite restorations. Int J Esthet Dent. 2021 May 10;16(2):168-184. PMID: 33969973.
2. Hardan L, Bourgi R, Kharouf N, Mancino D, Zarow M, Jakubowicz N, Haikel Y, Cuevas-Suárez CE. Bond Strength of Universal Adhesives to Dentin: A Systematic Review and Meta-Analysis. Polymers (Basel). 2021 Mar 7;13(5):814. doi: 10.3390/polym13050814. PMID: 33799923; PMCID: PMC7961712.
3. de Kuijper M, Gresnigt M, van den Houten M, Haumahu D, Schepke U, Cune MS. Fracture Strength of Various Types of Large Direct Composite and Indirect Glass Ceramic Restorations. Oper Dent. 2019 Jul/Aug;44(4):433-442. doi: 10.2341/18-111-L. Epub 2019 Jan 31. PMID: 30702412.
4. Politano G, Van Meerbeek B, Peumans M. Nonretentive Bonded Ceramic Partial Crowns: Concept and Simplified Protocol for Long-lasting Dental Restorations. J Adhes Dent. 2018;20(6):495-510. doi: 10.3290/j.jad.a41630. PMID: 30564796.

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