RAHUL DOSHI OFFERED SOME GUIDANCE WHEN TREATMENT PLANNING TO DEAL WITH MISSING ANTERIOR TEETH AND THE IMPORTANCE OF THE INCISAL EDGE
Replacement of missing anterior teeth can be challenging at the best of times, especially after having considered all the factors that integrate into an end design that provides both aesthetic and functional advantages.
Treatment planning and advice given to patients should include all possible options available.
However, there is often an interplay of demands and requirements that often tips the balance. When this occurs some guiding parameters can help.
There are many methods to consider before replacing missing anterior teeth.
Some of the more common options that should be discussed include:
- No treatment is often placed as an option. However, when considering missing anterior teeth this usually is not acceptable especially for those patients seeking cosmetic improvements.
- Short-term solutions can include – Snap on Smile, transitional dentures, and everStick Net (StickTech). However, in my opinion these are often considered as an interim treatment rather than the final result.
- Definitive cosmetic dentures can be acrylic, cobalt chromium or Valplast. Cosmetic dentures are fast becoming a lost art and science. But they should be considered seriously and are still an important facet to treatment planning.
- Bridges can be metal ceramic for anterior and posterior teeth or made entirely of ceramic for shorter span anterior teeth.
- Over dentures on retained teeth are also an option if suitable teeth are present.
- Implant treatment can include single teeth replacements, bridges and over dentures depending upon the circumstances.
The key difficulty as clinicians, and the key solution, lies in creating an ideal aesthetic and functional platform on which all teeth can work in balance and harmony. This is true whichever option is ultimately chosen.
Another consideration is that when dealing with missing anterior teeth we have to look at bone loss and where we want the position of the anterior teeth to be. This decision can be made easier by deciding the position of the all-governing central incisors.
In fact, to achieve a true aesthetic and functional outcome, it would be very difficult not to consider the position of the central incisors.
THE INCISAL EDGE
Hence, the key to integrated aesthetics and function would be to understand how to position the central incisors and more importantly the position of the incisal edge.
The incisal edge has many determinants that we need to assess and consider when treatment planning.
For dentate patients the incisal edge position determinants include:
- Speech. Here we need to assess the ‘f ’ and ‘v’ sounds. The incisal edges should ideally be at the vermillion border of the lips. Also, on making the ‘e’ sound the incisal edges should be half way between the upper and lower lip borders. The ultimate test is the speech itself.
- Anterior guidance. The position of the incisors and their angulation plays a major role in preventing posterior interferences. For example, there should be no balancing contacts (non working contacts) on protrusive movements if natural posterior teeth are present. For edentulous patients however, we do need balancing contacts (working contacts) on protrusive movements to stabilise a complete denture.
- Adequate lip support. The anterior teeth should provide adequate lip support.
- Aesthetics of centrals. When considering the position and angulation of the incisors the aesthetic result should also be taken into account.
For instance, the width: length ratio of central incisors should be approximately 75-85%. Also, what is the correct overbite and overjet for that particular patient?
All these factors should be planned beforehand. For edentulous patients the incisal edge position determinants include all the above but there are also some great aids (available from Schottlander) to determining the correct end result:
- Alma Gauge – saves time by taking horizontal and vertical readings of the existing denture reference of the patients incisive papilla.
- Bite Gauge – helps to determine the correct vertical dimensions of the new and replacement dentures to help diagnose errors in the old dentures.
- Bite Plane – ascertains the occlusal planes of the teeth (including the ala-tragal line) into acceptable anatomic and aesthetic positions.
- Other intra-oral and extra-oral landmarks. Evaluating options for treatment of missing anterior teeth cannot be successful without taking the very important central incisors into account. Despite the difficulties that can arise there are many innovative tools and aids to assist in designing the correct end result.