‘Can You Fix This?’ by Dan Grob, DDS, MS, editorial director, Orthotown magazine

If you’ve been in practice for a while, or even if you’re new to the profession, you can count on plenty of parents or friends of your young patients approaching you, pointing to their lower front teeth, and asking, “Can you fix this?”

If you’re somewhat new to the game, haven’t been burned in the past or are willing to dust off the consequences, you say, “Yeah, no problem.” If you’re careful, and likely have been burned in the past, you say, “Most likely, but let me get full records.” At this point, the patient may appear confused at your caution and full-blown concern.

No matter how innocent a couple of crooked lower incisors may look, undoubtedly there are accompanying side effects or other conditions lurking around the corner that may make your initial offer to fix it with a retainer one of the poorest decisions you’ll make—and surely regret.

Look at this finished treatment result after a young patient’s second round of orthodontic care (Figs. 1a and 1b). The patient said she regretted having her lower incisor removed. But how do you prevent getting into a situation like this? In my article that ran in the November 1995 issue of AJO-DO, “Extraction of a Mandibular Incisor in a Class I Malocclusion,” I discussed removing one lower incisor to alleviate crowding from both a Bolton discrepancy and a slight Class III skeletal tendency. Portions of that article justify the treatment plans I’ll discuss here and provide the basis for limited treatment in many situations.

In addition, the four elements of my “Treatment by 12s” philosophy (tooth eruption and drifting, skeletal imbalance, temporomandibular joint function and airway, and muscular function and balance) allowed me to consider what caused the relapse and arrive at a treatment plan.

Adults provide a huge source of business for the orthodontist. As you treat younger patients, their parents and other siblings are left to linger around the office. If your team is up to speed, you can use that time to nudge a good percentage of them to replace the patient you’re currently treating.

Some of the options available to clinicians include limited fixed appliances, with or without interproximal reduction (IPR), or removal of one lower incisor if more crowding warrants it. Clear aligners also are available ... as is the occasional decision to not touch the patient or situation with a 10-foot pole.

For the most part, the patients who follow were adult relapse situations and presented with their own sets of conditions that made careful diagnosis and treatment planning necessary.

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  Fig. 1a: Removing a lower incisor for crowding has its drawbacks and side effects.

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  Fig. 1b: The lateral X-ray shows there probably was an alternative to removing a lower incisor.

Case 1: Lower fixed appliances
There’s nothing like meeting someone at a national orthodontic meeting whose daughter, a young adult, has crooked lower teeth. The patient’s lower fixed retainer had come loose and—yes, you got it!—her teeth had begun to shift. Options included doing nothing, making a spring retainer and having her father, the marketing director for a prominent wire company, give me some clear brackets to test.

When I encounter a tightly coupled occlusion, slight tooth-size discrepancy resulting from a restored lateral incisor in the maxilla, and relapse, I’m always concerned that just aligning the teeth will force the crowding into the upper dentition and lead to complications. This could cause the mandible to distalize or to place pressure on the TMJ. Worse yet, if muscle balance and function is such, spaces may open in the upper dentition, or wear could appear in the lower. We all know how uncomfortable that situation is and how difficult and embarrassing it is to recover from.

Because of the tight occlusion of upper and lower incisors, before treatment I elected to mount diagnostic casts in addition to gathering complete diagnostic records. They helped determine if there was a forward slide from the hinge position into maximum intercuspation. Thankfully, there was a forward slide with some extra overjet and room to position the rotated teeth. This allowed for forward movement of the incisors without trapping the lower dentition behind the upper.

The retainer was removed, braces were placed and treatment was completed. A new bonded 3-to-3 retainer was placed and the patient maintains regular follow-up visits to make sure the bonded retainer stays secure.

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  Fig. 2a: A broken lower retainer resulted in several teeth shifting.

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  Fig. 2b: A tooth-size discrepancy and a restoration complicates the re-treatment of lower crowding.

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  Fig. 2c: Casts mounted in centric relation showed some shift forward that could be utilized for teeth alignment.

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  Fig. 2d: Because there was a Co-Cr shift, lower appliances were placed to move teeth into the freeway space—a leveled Curve of Spee.

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  Fig. 2e: A new bonded retainer was placed.

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  Fig. 2f: The overbite and crowding were slightly reduced.

Case 2: Aligners and IPR
The mother of a young Class III patient approached me about her lower incisor crowding. Frustrated because other doctors had offered suggestions such as removal of bicuspids and treatment with temporary anchorage devices, she approached me for a solution. It was helpful to understand the family history with her young daughter in treatment. The situation was compromised by a tooth-size discrepancy that resulted from missing lateral incisors with canine substitution.

A trial wax-up and a scan for clear-aligner therapy were ordered. The wax-up indicated that removing a lower incisor would work but would require more aggressive IPR on the upper dentition, as evidenced in the casts. However, the ClinCheck software showed that a generous amount of IPR extending through the bicuspids could achieve coupling of the incisors and treat the irregularities. It appeared as if the overall smile was broader with this treatment. The nonextraction plan was accepted and we began treatment.

IPR was performed in the lower arch and aligners were utilized. As with many patients, the plastic was not worn as religiously as desired and treatment took longer than expected, requiring some refinement. However, the patient was recently placed into retainers and is maintained on a recall schedule.

The result is acceptable and with good retainer treatment should last well. The overlap is improved and the midlines were made to be more coincident.

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  Fig. 3a: A bonded lower retainer broke, which led to crowding relapse.

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  Fig. 3b: The anterior view shows a tooth-size discrepancy as well as a crossbite and midline issue.

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  Fig. 3c: A dual-arch wax-up.

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  Fig. 3d: ClinCheck software was used to estimate treatment and IPR.

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  Fig. 3e: Refinement to further correct midline.

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  Fig. 3f: Invisalign treatment with IPR solved the relapse malocclusion.

Case 3: Removal of a lower incisor
This situation illustrates one of the first adults I treated where lower incisor crowding was not because of relapse. This patient had always wanted braces, but her restorative dentist suggested she obtain treatment first. There was more crowding in the lower arch, partly from a primary tooth-size discrepancy and many restorations. A trial was performed to see how feasible it was to remove the one lower incisor.

After reviewing the casts, it was clear that a lower incisor extraction would not result in excessive overjet. To completely couple the dentition, some IPR of the upper dentition would assist in retracting the maxillary anterior teeth into proper occlusion.

One lower incisor was removed and, as you can see, the upper IPR helped with the overjet. The patient finished with each of the lower canines positioned underneath the upper lateral incisors. This provides a functional occlusion with disclusion during lateral motions.

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  Fig. 4a: Primarily upper crowding with much lower irregularity.

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  Fig. 4b: Lower crowding was more severe than the upper.

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  Fig. 4c: A trial wax-up shows how little IPR would be required to keep the anterior teeth coupled.

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  Fig. 4d: A trial wax-up shows how little IPR would be required to keep the anterior teeth coupled.

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  Fig. 4e: IPR was performed to achieve coupling of the incisors.

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  Fig. 4f: The maxillary midline splits the lower remaining incisor.

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  Fig. 4g: A bonded lower incisor.

Case 4: Aligners and no IPR
Invisalign, like most other orthodontic therapy, is not ideal after complete restoration.

This patient presented after restoration of all upper teeth and lower molars. After receiving an extensive dose of porcelain, she was told she needed aligners to organize her lower incisor teeth. She sought the opinion of an orthodontist because she believed something was not right.

I confirmed her suspicion that Invisalign should probably have been performed before her cosmetic treatments, but a ClinCheck analysis persuaded me that we would not need to move her recently restored incisors or buccal segments. Because the lower bicuspids were inclined to the lingual and the volume added to the upper expanded the width, uprighting and noninterproximal treatment was performed. We could broaden her lower smile to match her upper.

Two stages of aligners were used to complete care. The last set prescribed intruded the lateral incisors so I could equilibrate the worn edges of her lower incisor teeth, make them appear even and eliminate further ceramic treatment.

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  Fig. 5a: Treatment for lower
  crowding was suggested
  after complete restorations.

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  Fig. 5b: Lower crowding confined to the natural teeth.

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  Fig. 5c: Excessive overjet
  to alleviate the crowding.

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  Fig. 5d: ClinCheck text to assess possibility of treatment.

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  Fig. 5e: The first treatment plan and ClinCheck.

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  Fig. 5f: Note the uprighting of the buccal segments.

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  Fig. 5g: Final result.

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  Fig. 5h: Refinement to intrude the lateral incisors.

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  Fig. 5i: Final.

Case 5: Best not to treat
Sometimes it’s best to avoid trouble. After a complete dental reconstruction short of the lower incisors, my patient’s mother presented with a deep bite, tight occlusion and absolutely no Co-Cr shift. Without moving the upper incisors out of the way, there was no room for the lower crowding to unravel.

Invisalign was proposed with IPR to gain room for the treatment and align the incisors. The Curve of Spee needed to be leveled. The patient declined and decided to receive lingual appliances in another practice. As of this writing, treatment has been going on for more than a year, and chipped incisor porcelain on the upper, space issues and a vague finish timeline have left the patient frustrated.

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  Fig. 6a: Completely restored occlusion with slight lower crowding.

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  Fig. 6b: Crowding and displaced lower cuspid requires repositioning of the upper dentition.

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  Fig. 6c: No shift or room to restore lower teeth.

Conclusion
Some typical adult relapse and minor crowding situations were documented and discussed. They included solutions where attention to joint and occlusal function, muscular balance and tooth-size discrepancy were in play. As described in the “Treatment by 12s” philosophy, most treatment and relapse situations in orthodontics involve tooth eruption and drifting, jaw discrepancies, airway and muscular balance, and temporomandibular function.

If you are aware of these factors, you usually can approach treatment methodically and with minimal disappointment.