Bleach, Infiltrate, Restore – Part 2

Dental bleaching is a treatment protocol that has been widely accepted as being a minimal intervention form of treatment with minimal occurrence of adverse reaction. Research suggests that home-whitening is the procedure that is least likely to lead to tooth sensitivity, and that light-activation confers no benefit to the amount of whitening achieved (3). However, in the context of white spot lesions, it is paramount that the patient is advised that although dental bleaching is a staple pre-requisite, it can sometimes increase the prominence of the white spot in the short-term.

As the previous article points out in this series, white spots can be a sincere concern amongst many patients and often can make them self-conscious. The more traditional methods of restoration can be considered as being far too invasive, such as indirect veneer restorations, or even direct composite bonding. Minimal intervention dentistry has been described as a contemporary approach to dentistry which requires ultraconservative operative management of patients (1). This follows a simple philosophy, that the less we do, the longer the teeth are likely to function throughout life (2). The focus of this article is the restorative procedure of the resin infiltration and direct composite bonding.

However, as a case study outlined a period of 14-day home whitening can often lead to the surround enamel assimilating the colour of the fluorotic lesion (4). Conversely, Gugnani and colleagues (5) found that whilst resin infiltration was superior to whitening is white spot concealing, the combination of ICON and whitening did not confer any statistical significant advantages. In the authors experience, patients are often dissatisfied with the colour of their teeth prior to whitening, and if there is a small chance that the ability of the lesion to be further masked is improved, patients will often be happy to whiten prior to infiltration. Subsequently, whitening should be considered as a important pre-treatment strategy to resin infiltration.

The combination of whitening, resin infiltration (with or without enamel preparation as required) and subsequent composite bonding offers patients with an ultraconservative approach in improving their appearance.

It must be stated, that minimal intervention and non-intervention are very separate, and is severe cases of white spots/fluorosis, subtle enamel preparation, using air abrasion, or in severe cases the dental turbine, may be indicated. However, the degree of preparation, by contrast to veneer preparations, and or white spot removal for composite placement is sufficiently less to warrant resin infiltration as the treatment strategy of choice (6).

So the patient has completed 2 weeks of at home bleaching with 16% Carbamide Peroxide whitening, using White Dental Beauty (Optident) for 2 hours a day. However, as several sources indicate (7,8), adhesion to bleached enamel is sufficiently weaker due to sparse, thin and fragile resin tag formation. Therefore a period of 2 weeks is left in between completion of whitening, and bonding to allow for any hydroxyl radicals to leach out of the teeth, and colour stabilisation once whitening is complete. Not only does this improve aesthetic integration and shade selection prior to any restoration, but also increases the functionality and longevity of any anterior bonding.

Fig.1

This is a 30-year old male, that has been self-conscious of his smile for at least 20 years, however refused to have invasive forms of treatment. He wanted to eliminate the white spots and accepted to improve the color with a bleaching but the misalignment of the incisal edges have never been of concern to the patient.

In this picture we can see the situation after 2 weeks bleaching with the bleaching trays at home and 16% carbamide peroxide 2-hours a day (White Dental Beauty, Optident). Next step is to remove the white spots with the resin infiltration technique.

Fig.2

Lateral vision. The white lesions are large and very opaque. This gives and indication that the lesions are deep in this case. This will almost confirm the need for some form of enamel preparation.

Fig.3

Retracted, contrasted view of incisors.

Fig.4

Adequate isolation is absolute requirement prior to any adhesive procedure. As outlined by Cajazeira et al (9), isolation is a mandatory requirement to improve outcomes with resin restorations, however the form of which is used does not offer any statistically significant advantage over any other. A caveat in this situation is the use of ICON, which uses Hydrochloric acid (HCl) as part of the erosion to access the white spot. In the authors experience, rubber dam should be considered mandatory for all resin infiltration cases.

Fig.5

Lateral view of isolation and White Spot.

Fig.6

As afore mentioned the etchant used in ICON is HCl, which is applied carefully to the white spot lesion. This is agitated around the white spot for 2 minutes. The etchant is removed with high-volume aspiration and then the tooth is washed for 30-40 seconds.

Fig.7

This is perhaps the most-important step in achieving optimal aesthetics. The ICON dry is an alcohol based solution that will mimic what the tooth will appear as once infiltrated with resin. In short, it is a test-drive, and ultimately provides the clinician a chance to determine whether optimal guising of the white spot has been achieved. As can be seen in this case, although a good degree of masking is occurring, the white spot still appears reasonably prominent, and therefore will require some additional enamel preparation, in this case with air abrasion.

Fig.8

Air abrasion is completed using 27um Aluminium Oxide Particles for 20-30 seconds at pressure no more than 4 bar. Not only does this allow, controlled and minimal removal of enamel, it also provides and increased surface area which is exposed to allow bonding to (10).

Fig.9

ICON Resin Infiltration. Resin infiltration requires a 2 minute application and agitation on the teeth, followed by a 1 minute for the resin to remain undisrupted on the teeth. This is followed by excess removal and teeth separation (using floss) and curing for 40 seconds on each tooth. A second application is repeated for 1 minute and cured again for 40 seconds to account for contraction shrinkage.

Fig.10

As can be seen the enamel defect on the 11 was sufficiently deeper than 21, and therefore more composite will be required to fill in the void created by the air abrasion.

Fig.11

In this case, adhesive from Kerr OFL (bottle 2) is applied and cured. The composite system used in this case was Cosmodent Renamel Microfill. Its superior aesthetics and ease of application make it the composite of choice. Also as there is already a palatal enamel wall, therefore strength is less of a concern, hence why a microfill would be optimal. The shades were agreed at initial situation, the shades agreed were A1 body (A1B), and incisal light (IL)

Fig.12

Lateral view demonstrating conformation in the labio-palatal dimension. The use of the anterior Compobrush allows for good, smooth and consistent adaptation of the material on the labial face.

Fig.13

Gross smoothing was completed using the 831-204-012 bur in the slow handpiece. Note the dehydration from rubber dam placement.

Fig.14

Some feint secondary and tertiary anatomy was created.

Fig.15

A week later, the restoration has  aesthetically integrated well with surrounding tooth structure, with some feint incisal edge effects. On this appointment the restoration was finally polished using sof-lex polishing discs, Premier Diamond Paste, and finally a felt wheel.

Fig.16

The Initial Situation.

Fig.17

The final situation.

The patient was truly delighted with the result, with complete masking of the white spot, the teeth appear natural and with minimal intervention but maximal outcome.

Conclusions

As this article demonstrates, from an aesthetic standpoint, the day of using a turbine to prepare teeth is having reduced indications. It is still indicated in some cases, and even when the turbine is required, adopting a minimal intervention strategy will always reduce the biological cost to the patient and prolong longevity. In addition, when embarking on any anterior aesthetic treatment, whitening should be considered as a staple pre-requisite as this may not be possible once restorations have been placed. Although the evidence is inconclusive, the author will always favour pre-restorative bleaching in the anterior region. Ultimately if this patient was ones daughter, would we be happy to pick up a turbine and prepare their teeth for indirect restorations as was initially proposed? (11)

Bibliography

1. Bannerjee, A. Minimal intervention dentistry: part 7. Minimally invasive operative caries management: rationale and techniques. British Dental Journal. 2013 (214): 107–111.

2. Jo E. Frencken, Mathilde C. Peters, David J. Manton, Soraya C. Leal, Valeria V. Gordan, and Ece Eden. Minimal Intervention Dentistry (MID) for managing dental caries – a review: Report of a FDI task group. International Dental Journal. 2012: 62(5): 223–243.

3. Carey, CM. Tooth Whitening: What we know. J Evid Based Dent Pract (2014), 14(suppl): 70-76

4. Knosel, M., Attin, R., Becker, K., Attin, T. A randomized CIE L*a*b* evaluation of external bleaching therapy effects on fluorotic enamel stains. Quintessesnce International (2008); 39(5): 391-9.

5. Gugnani, N., Pandit, IK., Gupta, M., Gugnani, S., Soni, S., Goyal, V. Comparative evaluation of esthetic changes in nonpitted fluorosis stains when treated with resin infiltration, in-office bleaching, and combination therapies. Journal of Esthetic Restorative Dentistry (2017); 29(5): 317-324.

6. Torres, CRG, Borges, AB, Torres, LMS, Gomes, IS, Simões de Oliveira, R. Effect of caries infiltration technique and fluoride therapy on the colour masking of white spot lesions. Journal of dentistry 39 (3), 202-207, 2011

7. F Garcia-Godoy, WW Dodge, M Donohue, JA O’quinn. Composite resin bond strength after enamel bleaching. Operative Dentistry 18, 144-144, 1993

8. Nour El-din, NK., Miller, BH., Griggs, JA., Wakefield, C. Immediate Bonding to Bleached Enamel. Operative Dentistry (2006); 31-1: 106-114.

9. Cajazeira, M.R.R., De Saboia, T.M., Maia, L.C. Influence of the operatory field isolation technique on tooth-coloured direct dental restorations.  American Dental Journal (2014); 27: 155-159

10. Vivek S Hegde, Roheet A Khatavkar A new dimension to conservative dentistry: Air abrasion. Journal of conservative dentistry (2010): 13 (1): 4-8

11. Kelleher, MGD. The “Daughter Test’ in Aesthetic (‘Esthetic’) or Cosmetic Dentistry. Dental Update2010: 37(1):5-11

Dr. Shiraz Khan

Dr. Shiraz Khan graduated from the University of Birmingham Dental School in 2013. Having successfully completed foundation training and winning several prizes, he finished his dental core training in a range of specialisms including Restorative Dentistry at Croydon University Hospital, Guys and St Thomas’s. He is currently placed in private practice in the heart of London (Devonshire Place, Chelsea, Fulham and Clapham). Shiraz has heightened his profile at this albeit early stage, being invited to lecture to young dentists around the country, as well as having lectured internationally. Most recently he has returned from Tehran, Iran lecturing at the EXCIDA 57th international congress regarding aesthetic dentistry. Progressing in his career in additional post-graduate qualifications and building a portfolio of achievements means that Shiraz is nothing short of an aspirational individual. He has recently started his Masters in Restorative Dentistry at the University of Birmingham. He invests time into his career development and experience, regularly sharing with like-minded professionals. Most recently he has won the Fast Track 4 Award in recognition of his commitment to dentistry and becoming a leader of the future, and has won the Best Young Dentist 2017 at the Dentistry Awards. Finally, he has also been recognised as ‘The Rising European Star in Dentistry 2018’. Most recently his hard work and efforts were recognised by the Young Dentist Academy who appointed Shiraz to become The Director.

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