The rehabilitation of worn dentition represents a complex and demanding task for the dental practitioner, and routinely involves porcelain onlays or full crowns. But why should we choose the indirect techniques which involve preparation? Are we able to simplify our techniques? Can we proceed with non-prep restorative dentistry?
In recent years, the Injection Flow Technique has become more popular (1, 2), however this technique poses many drawbacks as it is impossible to place rubber dam (index would not fit properly to the tooth structure isolated with rubber) and it is accompanied by composite excess, which is extremely difficult to remove.
The method which utilises the preheated conventional composite resin was described as ”index technique protocol” by Ammanato et al (3) and designed for moderate worn dentition. The drawback of this technique was the relative instability of the trimmed single element on the restored tooth surface.
In the presented clinical case the new method, where more predictable stability is achieved by a “composite ball technique”, is described. All premolars and molars that need to be restored, are temporarily modified by means of adhesively bonded “composite ball’’ at the cervical part of buccal wall (approx. 1.5 mm above the gingival line, in order not to interfere with the ruberdam clamp). Only after the composite ball modelling and appropriate polymerisation, can the impressions be taken and sent to the laboratory in order to perform the wax up in the newly established VDO.
Another clinical issue of the “index technique protocol” is a significant risk of composite excess in the interproximal area, which can be easily avoided by introducing “pre-polymerisation procedure” that is also a new modification presented in this article.
Fig.1
A 17 year-old female patient presented to the dental clinic with significant tooth wear.
Fig.2
Intra-oral view.
Fig.3
Occlusal view showing diffused wear.
Fig.4
Dr John Kois claims “… In normal conditions, teeth wear by 11microns/year, which takes 100 years to loose a mm of tooth structure …” (4) So if we see a 17 year-old patient with severe tooth wear and exposed dentin, this clinical situation requires an intervention, especially considering the fact that dentin wears much faster than enamel (5).
Fig.5
In complex clinical cases, the treatment plan starts with aesthetic assessment (6), consequently in this case the new length of upper anteriors and the new incisal position were planned. Considering the information recorded from the lips-in-repose position.
Fig.6
The upper anterior wax up was fabricated in the lab, followed by a mock up.
The most important aims of the mock-up were to:
– understand and confirm the vertical and horizontal position of the incisal edges,
– verify the patient’s aesthetic expectations,
– plan the new VDO based on the recently verified length of the upper anterior teeth.
Fig.7
TMJ loading test resulted negative and Kois Deprogrammer (KD) was delivered for 4 weeks in order to facilitate the CR registration. The procedures concerning the KD were described in a previously published article (7).
After 4 weeks of wearing the Kois Deprogrammer, the patient confirmed deprogrammation. When the patient closed their mouth and the same initial contact was confirmed – the patient was deprogrammed. Repeatability is the key criterion to determine when the patient is deprogrammed (7). The CR was registered by means of the KD device and bilateral posterior silicone bite records.
Fig.8
All the lower premolars and molars that needed to be restored were temporarily modified by means of adhesively bonded composite “ball” stops placed at the cervical third of the buccal wall (approx. 1.5 mm above the gingival line, in order not to interfere with the rubber dam or clamp). Only after the composite stop “ball” fabrication and appropriate polymerization the impressions could be taken.
Fig.9
Based on the CR and face bow registration, the models were mounted in the articulator, and the new VDO was established with respect to the previously confirmed length of the upper anteriors, and adequate parameters of the overbite and the overjet. Then the upper and lower arch were waxed-up respecting the recently established VDO.
Fig.10
A transparent index was fabricated using a rigid silicone material (Oxford Trans, Oxford Scientific). The transparent index was trimmed with a surgical blade No 10, taking care to separate the single elements so as to achieve a unique matrix for each tooth that needed to be restored. It is important to cut each index in order to create a 1 mm margin above the gingival level so as not to generate any interference with the gums or rubber dam during the restorative phase.
Fig.11
The specially created “V’’ shape incision was obtained to establish the reference point on the composite stop “ball” surface. During the try in of the index on the model and in the mouth, it is recommended to draw a line along the “V” incision using a pencil. The reference point created on the composite “ball” is crucial in order to control the index positioning, similarly to the stopper, which is used on the root canal instrument in root canal treatment. As in endodontics the stopper is used not to exceed the working length, in this case the composite “ball” controls the position of the index.
Fig.12
In the next step, the occlusal chimney was performed in order to reduce the amount of the composite excess in the inter-proximal area. To proceed to the restorative stage, rubber dam isolation was performed and teeth were restored quadrant by quadrant. The occlusal surfaces of posterior teeth were delicately roughened with a diamond drill and then air abraded with 27 micron aluminium oxide. Then after 20 s of etching, teeth were rinsed and delicately dried. The bonding system was meticulously placed, and polymerized.
Fig.13
Each restored tooth was isolated inter proximally by means of a metal strip, and then the index position was checked in order to avoid any interferences. The index was pushed down until the reference point at the line marked on the composite “ball”.
Fig.14
The index was held by continuous pressure in the appropriate position while the composite resin excess was gently removed with Fissura instrument (LM Arte).
Fig.15
The 3 seconds pre-polymerization procedure and index removal in order to gently cut the “spongy” and barely cured composite excess with scalpel No 12.
After removing major composite excess, the final polymerization was obtained by light-curing each restoration surface for 40 seconds.
Fig.16
The restoration protocol started with the most distally positioned tooth and proceeding towards the mesial. First, the posteriors of the 4th quadrant and then the ones of the 3rd quadrant were completed.
Fig.17
In order to improve the adhesion of the new restorations in the anteriors, a chamfer and bevel was performed.
Fig.18
The mandibular anteriors were restored utilising palatal silicone index fabricated on the wax up. After building the palatal shell, the proximal frames were created using the Varistrip (Garrison).
When the outer frame of new restorations were ready (palatal and proximal), the restorative process proceeded very easily. Mamelons were created in the dentin layer and a 0.5 mm enamel layer created the outer surface (8).
Fig.19
To restore the upper front teeth, the palatal silicone index and Unica Anterior matrix (Polydentia) were used in order to create the frames for predictable placement of the dentin and the enamel material (Enamel plus HRi Bio Function, Micerium SpA).
Fig.20
Smile of the patient after direct composite restorations of the upper anteriors.
Fig.21
Then the upper posteriors were obtained in the same manner as the lower ones.
Fig.22
The photograph of completed lower arch. Occlusal equilibration took around 30 minutes and allowed to achieve the equal, simultaneous occlusal contact points. Also, the 8-micron occlusal paper was not held between upper and lower anteriors in MI relation.
Fig.23
The photograph after complex rehabilitation with direct composite restorations.
Fig.24
The before and after photographs of complex rehabilitation with direct composite restorations.
Conclusions
1. Full occlusal rehabilitation with direct composite restorations is a conservative option that can be widely used in clinical practice today.
2. The index technique can be the recommended method of transferring the occlusal anatomy based on the wax up, especially when structural loss does not severely compromise the proximal walls.
3. “The composite ball” technique seems to be an accurate solution in order to facilitate the stable positioning of the index and to avoid index displacement.
4. “The composite ball” technique facilitates retention of the rubber dam during the restorative protocol.
5. The “pre-polymerisation procedure” becomes a viable option in order to avoid composite resin excess.
Bibliography
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2. Terry DA, Powers JM. Using injectable resin composite: part two. Int Dent Afr 2014; 5:64–72.
3. Ammannato R, Ferraris F, Marchesi G. The “index technique” in worn dentition: a new and conservative approach. Int J Esthet Dent 2015; 10:68–99.
4. Kois J. 2019 Symposium July 18-20, Kois Centre, Seattle, USA
5. Kim JL, Karastathis D. Dental Hygiene Theory and Practice. 3rd ed. St. Louis, MO: Saunders-Elsevier; 2010. Dentinal hypersensitivity management. In: Darby ML, Walsh MM; pp. 726–35.
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7. Zarow M. Finding the centric relation – the Kois deprogrammer. Styleitaliano.org 2018.
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