Interdisciplinary Management of Worn Anterior Teeth: Facially Generated Treatment Planning

Frank M. Spear, DDS, MSD
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INTRODUCTION
For most dentists, treatment planning is a straightforward process whenever the patient has well aligned teeth, an acceptable oc­clusal relationship, and healthy bone and gingiva. In these cases, treatment planning is essentially determining what the restorative plan will be on a tooth-by-tooth basis.

When teeth are worn, and the patient has occlusal issues, the treatment planning process becomes much more complex and confusing. Any attempts at determining a treatment plan using the traditional tooth-by-tooth approach only leads to greater confusion and an unclear vision of the end results.

Facially Generated Treatment Planning
Since the early 1980s, I have called the treatment planning process that I use for more complex patients facially generated treatment planning (FGTP). This refers to the fact that tooth position must be planned first, as a key reference for tooth position is the face and lips, hence the name facially generated.1,2

The FGTP process refers to the sequence of how we, as dentists, treatment plan complex patients; it is not the sequence in which we will treat the patient. The sequence of FGTP is very linear and can be applied to any patient; the sequence of treatment will vary from patient to patient and must be individualized.

The FGTP process consists of 4 separate phases of planning.

Phase 1. Aesthetics: To identify the desired maxillary tooth position, gingival levels, and papilla levels, including an assessment of the mandibular incisors’ position aesthetically as well. The aesthetic phase of planning is similar to the first phase of managing any edentulous patient—one has to position the maxillary teeth and gingiva before the occlusion can be developed.

Phase 2. Function involves developing the oc­clusion, which is now possible since the desired position of the maxillary teeth has been identified. The function component of FGTP involves the assessment of the temporomandibular joints (TMJs) and muscles, as well as any parafunctional patterns the patient may have. The occlusal development involves positioning the mandibular teeth to produce the desired occlusal relationships, overbite, and overjet, against the previously identified maxillary tooth position.

Phase 3. Structure consists of the restoration or replacement of teeth. For most restorative dentists, this is the phase with which they are most familiar, and the one they treatment plan every day in patients who don’t have complex problems. It is also the phase they try to plan first in patients with complex problems—such as severe tooth wear—and then get confused because there isn’t any room to perform restorations. That’s why the structural phase of treatment planning must come after the aesthetic phase and the function phase, because those 2 phases identify the corrections necessary in tooth position, which will then always provide the space needed for the restorations.

Phase 4. Biology incorporates the planning of any endodontic therapy, and any perio­dontal or oral surgery. This phase is evaluated last because the desired tooth position, tissue position, occlusal relationship, and restorative plan all need to be known before finalizing any endodontic, perio­dontic, or oral surgical planning.

Essentially the FGTP process consists of aesthetics, function, structure, and biology as the phases of the planning. Dentists who use the process routinely shortened it to AFSB (or EFSB) when referring to each of the phases.
In the following case example, a patient with significant maxillary and mandibular anterior tooth wear will be used to demonstrate the process.

CASE REPORT
In this patient, the maxillary centrals were retroclined, there was minimal overjet, and he had an almost end-to-end occlusal relationship between the maxillary and mandibular centrals. He had minimal posterior tooth wear and minimal canine wear. In addition, he had no TMJ or muscle issues, and needed no posterior restorations other than the replacement of a lower left first molar. The wear on the anterior teeth was from attrition, not erosion or abrasion, and occurred because he moved his mandible into a protruded position and then into lateral positions. He was aware of doing this during the day at work, and stated it had become a habit he used when stressed; a habit he would be unlikely to stop (Figure 1).

This patient presented the classic challenge for restorative dentists in that he wanted his anterior teeth restored but had no room to place the restorations. It is critical in any wear case to realize that if worn teeth are in occlusal contact with the opposing teeth, there are only 2 possibilities for how that could happen: either the worn teeth erupted, or the patient lost vertical dimension. When there is minimal to no posterior wear, it is unlikely the patient has lost any vertical dimension; therefore, in this patient, my dental team could assume that there had been anterior eruption following the tooth wear, and correcting the tooth position would regain space for restorations (Figure 2).

Figure 1. The patient presented with severe wear of the maxillary and mandibular incisors and minimal posterior or canine wear. Figure 2. Due to the eruption that occurred as the teeth wore, they were too short, and there was no room to restore them.
Figure 3. The upper lip at rest showed no tooth display. Figure 4. The proposed changes to the incisal edge position were drawn on a photo, adjusting the incisors to the correctly positioned canines and posterior teeth.

The Aesthetics of Phase 1
The first teeth evaluated in this phase were the same as the first teeth that are set in a maxillary denture: the central incisors. The central position was evaluated using photographs of the patient with the lip at rest, as well as in a full smile.

There is never just one acceptable incisal edge position. In general, it is desirable to show a range from 1.0 to 4.0 mm of the central incisors with the lip at rest. In patients with anterior tooth wear, it is not uncommon to see no anterior tooth display at rest (Figure 3).3,4 Ultimately, the amount of tooth display at rest is not what determines the final incisal edge position; however, the largest factor impacting the smile is the amount the patient’s lip moves (lip mobility) from its rest position to its highest point in a full smile. For most patients, the range of lip mobility is between 6.0 and 8.0 mm.

In patients with worn anterior teeth, the teeth need to be lengthened, and the clinician can use the amount of tooth displayed at rest and the amount of lip mobility to determine how he or she will lengthen them—by adding to the incisal edge, apically positioning the gingiva, or both. This patient had additional guides for the central incisor position: unworn canines and posterior teeth. Placing the incisal edges so to be well aligned with the posterior teeth would likely also produce an acceptable display at rest and in a full smile.

It is very helpful for the clinician to draw the proposed tooth position changes on a photograph to visualize the planning process. This can be done very quickly on a computer with the patient’s images loaded into programs such as PowerPoint on a PC or Keynote on a Mac. In this case, pre-drawn templates of the anterior teeth were used which could be copied and pasted on the desired image, then resized for that particular photograph. This reduces the drawing process to a few minutes’ time but provides an excellent visualization of the end result. The same drawing can then be shown to the patient to help him or her visualize the changes being proposed.

Once the changes needed for the centrals have been identified, the new central position will now guide the changes necessary for the remaining maxillary teeth, starting with the laterals, then canines, premolars, and finally molars, creating a pleasing arch form and smile-line, determined primarily by aesthetics (Figure 4).

Following the identification of the desired tooth position, the gingival levels for all of the maxillary teeth can be evaluated. Again, starting with the central incisors, the identification of the desired gingival margins involves choosing gingival margins levels that create a pleasing width-to-length ratio for the centrals relative to the chosen incisal edge position. This is usually a ratio between 75% and 80%.5 Using the drawings, it is very easy to measure the width-to-length ratio that would exist after lengthening the incisal edges (in this case, 92% [Figure 5]). The clinician can now redraw the gingival margin levels to a more aesthetically pleasing perspective (in this case, 77%). The drawings gave both the clinician and patient the opportunity to visualize what was necessary, and what the desired outcomes for treatment would be (Figure 6).

Figure 5. Measuring the width-to-length ratio. After the incisal edge position was corrected on the photo, there was still a very short and square appearance to the teeth. Figure 6. Altering the drawing to depict apically repositioning the gingiva showed the desired final result with a pleasing width-to-length ratio.
Figure 7. The patient’s preoperative smile demonstrated that a significant amount of his lower anterior teeth had worn, illustrating that they had hyper-erupted also. Figure 8. The initial phase of orthodontics to procline the retroclined maxillary anterior teeth, improving the overjet.
Figure 9. The use of rectangular wire to intrude the maxillary and mandibular incisors. Figure 10. After bracket removal, note the correct gingival levels and room that was created for the restorations.
Figure 11. The final maxillary and mandibular partial-coverage lithium disilicate (IPS e.max [Ivoclar Vivadent]) bonded all-ceramic restorations, from canine to canine. Figure 12. Close-up view of the completed maxillary layered lithium disilicate restorations.
Figure 13. The completed lithium disilicate all-ceramic mandibular anterior restorations. Note the absence of incisal embrasures, allowing a smooth lateral movement to minimize chipping. Figure 14. Final smile. Note the impact of intruding the maxillary and mandibular anterior teeth as compared to the initial smile.

The last part of the aesthetic phase is to evaluate the mandibular anterior position relative to the face. In this patient, the mandibular incisors were very short, yet quite visible in his smile, meaning that if restored to a normal length by adding to their incisal edges and leaving them in their existing position, they would be too tall in his smile, from an aesthetic standpoint. Here it was evident that the mandibular incisors had significantly erupted as they had worn, and like the uppers, would need the gingiva to be moved apically through orthodontic intrusion or crown lengthening surgery (Figure 7).

The Function in Phase 2
Upon completion of the aesthetic phase, the changes in maxillary tooth position and gingival levels have been identified. Alterations necessary in the occlusal relationship can be identified to allow the desired maxillary and mandibular tooth position to be achieved. In this case, increased overjet was needed.

Many times, in anterior wear cases, the teeth have erupted6,7 but are in a good position in relation to facial lingual position and inclination, and they have an acceptable overjet relationship. In these cases, either orthodontic intrusion or crown lengthening surgery can be used to reposition the bone and gingiva, followed by restorations.

In individuals with minimal overjet, such as this patient, the use of crown lengthening will not correct the occlusal relationship. In this case, the ideal treatment plan to correct the functional relationship would be orthodontics to intrude and procline the maxillary incisors, and to also intrude the mandibular incisors.8,9

The Structure in Phase 3
This phase is about deciding how to restore the worn teeth; ie, crowns versus veneers, and also what material to choose. In this patient’s case, following the orthodontics, there would be minimal need to reduce the incisal edges of the worn incisors for clearance during tooth preparation, as the orthodontics would have created the necessary space. The restorative plan for him was to use partial-coverage, bonded, all-ceramic restorations, made out of an aesthetic and yet high-strength material such as lithium disilicate (IPS e.max [Ivoclar Vivadent]) to resist his parafunctional behavior.

The Biology of Phase 4
With a clear picture of where this case was headed, the final questions would be whether there was a need for any endo­dontic treatment, periodontal sur­gery, or oral surgery. If the patient accepted the orthodontic treatment plan, there would not be a need for any of the above. If he did not accept ortho­dontic treatment, then crown lengthening would be necessary and, most likely, endodontic treatment as well on the over-erupted incisors so that adequate preparations could be done. However, it is important to recognize that the non-ortho plan could never correct the overjet to an ideal result, which was a significant problem in this patient’s case. The only other alternative would be crown lengthening and opening the vertical dimension of occlusion, meaning that posterior teeth that did not require restorations would need to be restored. In addition, the mandibular anterior teeth would end up significantly too tall in his smile.

Treatment Protocol
The patient accepted the orthodontic treatment plan as the best and most conservative way to go. Orthodontics was begun with straight-wire appliances to procline the maxillary anterior teeth and to start the alignment process (Figure 8). This progressed to rectangular wire to intrude the incisors, using the gingival margins of the canines as a guide for positioning the central gingival levels. The same approach was taken to intrude the mandibular incisors (Figure 9).

Following the removal of the ortho­dontic appliances, the gingival margin levels were now correct, and there was an anterior open bite across the incisors which would provide the necessary space for the restorative phase (Figure 10).
The final partial-coverage, bonded, all-ceramic restorations (IPS e.max) extended from canine to canine in the maxillary arch, and from the mandibular left canine to the mandibular right first premolar. It should be noted that extension to the canines in both arches and mandibular first premolar was done for aesthetic reasons (Figures 11 and 12).

Examination of the final mandibular anterior restorations showed minimal incisal embrasures. This is an alteration that allows patients with protrusive and lateral parafunctional habits to move across the maxillary incisal edges smoothly, with less risk of chipping or fracturing porcelain (Figure 13).

CLOSING COMMENTS
The goal of this article was to present an approach to treatment planning that can help interdisciplinary teams sequence the process of developing plans in a logical fashion for patients with complex problems. This process is particularly effective when used in group treatment planning sessions, such as a study club setting.

In my experience of using and teaching this approach for 3 decades now, FGTP provides an easy-to-follow, logical solution for otherwise challenging problems, particularly with patients who present with significant wear of their teeth (Figure 14).


References

  1. Spear FM, Kokich VG, Mathews DP. Interdisciplinary management of dental esthetics. J Am Dent Assoc. 2006;137:160-169.
  2. Spear FM, Kokich VG. A multidisciplinary approach to esthetic dentistry. Dent Clin North Am. 2007;51:487-505, x-xi.
  3. Vig RG, Brundo GC. The kinetics of anterior tooth display. J Prosthet Dent. 1978;39:502-504.
  4. Al Wazzan KA. The visible portion of anterior teeth at rest. J Contemp Dent Pract. 2004;5:53-62.
  5. Sandeep N, Satwalekar P, Srinivas S, et al. An analysis of maxillary anterior teeth dimensions for the existence of golden proportion: clinical study. J Int Oral Health. 2015;7:18-21.
  6. Craddock HL, Youngson CC. Eruptive tooth movement—the current state of knowledge. Br Dent J. 2004;197:385-391.
  7. Ainamo J, Talari. Eruptive movements in teeth in human adults. In: Poole DFG, Stack MV, eds. The Eruption and Occlusion of Teeth. London, England: Butterworths; 1976:97-107.
  8. Kokich VG, Spear FM. Guidelines for managing the orthodontic-restorative patient. Semin Orthod. 1997;3:3-20.
  9. Hempton TJ, Dominici JT. Contemporary crown-lengthening therapy: a review. J Am Dent Assoc. 2010;141:647-655.

Dr. Spear, a dual-trained periodontist/prostho­dontist, earned his dental degree and MSD in periodontal prosthodontics from the University of Washington. He is an affiliate professor in graduate prosthodontics at the University of Washington and maintains a private practice in Seattle limited to aesthetics and fixed prosthodontics with long-time practice partner Dr. Greggory Kinzer. He is the founder and director of Spear Education, and his memberships include the American Academy of Esthetic Dentistry, the American Academy of Restorative Dentistry, the American College of Prosthodontists, the Pierre Fauchard Academy, and the International College of Dentists. He is a former president of the American Academy of Esthetic Dentistry, and he can be reached at via email at info@speareducation.com or via the website at speareducation.com.

Disclosure: Dr. Spear is the founder and a shareholder and employee of Spear Education.