Compromise is the key to a successful treatment

23 August, 2011 / Infocus

The maxillary lateral incisor regularly causes a treatment planning dilemma. Structurally speaking, it’s one of the smallest teeth in the mouth, so there doesn’t have to be much restorative dentistry before the tooth is severely compromised.

Even in a disease-free mouth, restoration is frequently required due to trauma. In all but the lowest lip-line, there are significant aesthetic challenges: our restorative arsenal of materials all have minimum space requirements if they are to recreate natural shading. And with a structurally small tooth, the space is rarely available, resulting in either an even weaker tooth, over-contoured restoration or poor colour match (Fig 1).

Pulpal involvement and root canal treatment are also regular requirements bringing additional considerations. For example, is a post required? If so, what type? Or how do we avoid the ‘shine through’ of a dark root? (Fig 2)

Other considerations include considering if a lateral incisor should be used as a bridge abutment. What are the chances of root canal treatment being required after preparation? How successful is a bridge if a root canal filling (RCF) has to be carried out through the crown? What is the likelihood of fracture? (Fig 3)

How are we supposed to explain our decision-making processes to the patient? As more and more patients look for aesthetic restorations, smile enhancements, and the North American approach which aims for pure white and perfect symmetry (Fig 4), difficult treatment planning decisions for the lateral incisor are often required.

Unfortunately, a complicated but necessary decision-making process can often be by-passed in the planning process of the ‘smile design’ in order to get to what the patient wants. In such cases, the lateral is either re-veneered or re-crowned in the hope that it will structurally hold out and that the technician will sort out the aesthetics (Fig 5).

These decisions can lead to significant problems and, as much of this treatment is elective and costly, an unhappy patient is often not far behind.

Managing for success
The goal of any treatment plan should be to achieve the patient’s wishes, while addressing their dental needs in order to achieve long-term success.

Decision making is often made easier when each episode of treatment is prescribed on an ‘as required basis’, with cause and effect clearly visible and acceptable to patient and dentist alike.

But we also need to meet the patient’s expectations and the best time to find out if we are going to fall short is before we start treatment.

What is the patient’s perception of how long a restoration is going to last? If it is five years, for example, then this is a much better prospect for a challenging restoration than if they expect it to last forever.

That said, should we really be advising, as the most predictable option, any treatment that is not going to last 10 years? If we are aiming at 10 years’ survival for our restorations, then we need reliable information to determine under what circumstances we can achieve this.

For the recently qualified, and those that move practice regularly, you can’t rely on your own experience and therefore have to look to the literature for best practice and evidence.

Root canal treatment, for example, is predictably successful, if carried out correctly: rubber dam isolation, correct preparation, smear layer removal and delivery of disinfectant to the apex for the required period of time, etc.

Similarly, post-crown restorations are also predictably successful if:

  • The post is kept narrow and extends to the correct length
  • The post is made of the correct material – cast posts when there is only the ferrule remaining, fibre posts when there is plenty of dentine. You may not need a post anyway
  • The crown preparation has to extend over a minimum of 1.5-2mm of dentine (ferrule)
  • They are not used as bridge abutments.

Apicectomies, meanwhile, can be predictable if, again, certain criteria are met:

  • The root canal filling should be sound. (i.e. You know it has been carried out correctly)
  • The coronal restoration (most usually a post-crown) has also been carried out to the ideal criteria
  • The surgical procedure is carried out in accordance with current best practice, including sterile field and magnification (Fig 6).

Other criteria
There are many other factors which may or may not influence predictable success. For example, these include:

  • Does the patient have a history of caries and periodontal susceptibility? Advanced restorations should be advised against in patients that cannot demonstrate an ability to maintain them (Fig 7).
  • Occlusal factors – how many teeth remain within the arch? Is the patient a bruxist? Is the tooth going to have to carry more weight than it may in an otherwise intact arch?
  • Aesthetics – does the patient have a high smile line and show the gingival margins of the lateral incisor? What is their gingival biotype and susceptibility to recession? (Fig 8)

Failure to address and meet any of the required criteria is, of course, a compromise: this is the key to successful management of any situation – knowing the compromises and addressing them.

Drawing up a plan
To formulate the correct plan which addresses, in as far as possible, all potential problems, it is necessary to:

1. List all the potential compromises
2. Outline how they may be managed
3. List all potential alternatives and their compromises
4. Discuss your findings with the patient so that they have the opportunity to make as fully an informed decision as possible.

This can sound a lot more complicated that it is, but should be really no more than having a conversation about what we have already mentally assessed.

Example one
A 46-year-old man fell off a mountain bike and partially avulsed tooth 11 and decoronated 12, with fracture extending palatally subgingivally. Both teeth were vital with no restorations before. His arch was intact, he had good oral health, no perio and no bruxing habit. There was a medium to high smile line. (Figs 9 and 10).

As part of emergency treatment, tooth 11 was immediately repositioned, while a glass ionomer was used over the vital fracture in tooth 12.

Treatment options
Further options for tooth 12 were then discussed with the patient. These were:

1. Direct build-up with composite resin

  • Minimal enable for bonding
  • Likelihood of devitalisation.

This could be managed by Elective RCT for post-retention of coronal restoration (composite, veneer or crown).

2. Full crown

  • Insufficient coronal tooth structure for 2mm ferrule
  • Insufficient tooth structure for bonding all ceramic restoration.

These compromises could be managed by crown lengthening or orthodontic extrusion to create sufficient tooth structure for ferrule. Due to a high smile line, only orthodontic extrusion would be acceptable.

Alternative treatment options
A number of other possible treatment options were considered. All of these involved the extraction of tooth 12:

1. Partial denture
Compromise: denture is removable.
2. Resin bonded bridge
Compromise: challenging aesthetically and likely to have visible tissue loss
3. Conventional fixed bridge
Compromise: tooth 11 already comprised, unnecessary destruction of tooth 13.
4. Implant crown
Compromise: possible additional surgery, challenging with high smile line and requires greater investment in the first instance.

Choosing a solution
Outlining these options only involved a 10-
minute conversation but it meant that the patient was taking active responsibility for the treatment he chose.

In this case, the patient chose to electively have the remaining root root-filled and a fibre post placed to carry, in the first instance, a composite resin restoration.

Tooth 11 was also root-filled in the knowledge that this tooth will most likely be lost to external resorption in the future (Fig 11).

The treatment option that we probably already knew from the outset to be the most practical option was therefore explained to the patient in a way that allowed him to accept the compromises. Theoretically, this should allow an easier passage to the next line of treatment when the tooth fails and has to be removed.

It is also important to remember that just because we ourselves might not go through a particular treatment or do not have the skill-set or experience to provide a particular aspect of that treatment, we should not fail to offer it.

Orthodontic extrusion, for example, may seem to us as an unnecessary delay to providing the treatment and possibly not worth it, but it is the patient that needs to make this choice (Figs 12 and 13).

Accepting compromises on the patient’s behalf, however, will ultimately end up with an unhappy patient and the possible loss of the relationship.

This article was submitted by Edinburgh Dental Specialists.

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