Re-reattachment of a Fractured Maxillary Central Incisor: A Case Study

There are two main categories of tooth-fracture injury^3,4; complicated fractures are those with periodontal and/or pulpal involvement, while uncomplicated fractures are simple coronal fractures without periodontal or pulp involvement. This second category may involve enamel, dentin, or both.

According to most publications reporting on the incidence of dental trauma and crown fractures, the most common fractures occur as uncomplicated crown fractures (second category above). Children and teenagers are the most affected age groups, with males at a higher risk than females.^2,5 The maxillary central incisors are the teeth most often affected; they are involved in approximately 80% of fractures.⁶

Pasini et al⁷ found that 89% of dental fracture injuries had soft-tissue involvement; extra-oral soft tissues (lips) were involved in 46% of those cases. They also reported needing to retrieve a tooth fragment of the lower lip in order to reattach it.

Over the past 3 decades there have been a number of classification systems proposed for further description and categorization of tooth fractures. The main ones reported by Reis et al¹ are: Ellis and Davey (1970); Andreasen and Andreasen (1993); Baratieri, Monteiro, and Andrada (1998); and Spinas and Altana (2002).⁸ Ellis⁹ has also proposed a new definition for incomplete tooth fractures (ITFs), also known as cracked teeth.

Reattachment of the fractured coronal fragment to the remaining tooth structure has been shown to be an excellent alternative to conventional restorations such as resin composite build-up, veneer, or crown.⁵ This procedure may offer several advantages such as: conservation of natural tooth structure and esthetics,¹⁰ more predictable long-term wear,¹¹ a very cost-effective restorative option,¹ and excellent strength.¹²

The first case report on reattachment was published back in 1964 by Chosack and Eildeman. There has been very little published on clinical trials concerning reattachment, but case studies are quite numerous. In 2004, Reis et al published an excellent review on the various techniques and materials used for reattachment, and it is highly recommended by the author. Many different methods and materials¹³ have been used and reported since 1964, and the consensus seems to be that the technique is more important than the material itself. The materials that have been most popular are: filled and unfilled adhesive systems used alone or in combination with flowable composites, dual- or chemical-cured resin cements, and light-cured resin cements. Microfilled and hybrid composites in combination with adhesive systems are also used.¹

Figure 1 depicts a number of different methods/techniques that have been proposed as possible procedures for reattachment of fractured tooth fragments in a review article by Reis et al in 2⁰⁰⁴.1 The novelty of this case study is that it involves an uncomplicated reattachment of an original complicated attachment case. In other words, attachment after the first injury involved the pulp, and reattachment of the same portion of the tooth after the second injury did not involve the pulp. A Scandinavian multicenter clinical study on the longevity of reattached fractured teeth showed that, in many cases, debonding was caused by new traumas or non-physiological use of the restored teeth.¹⁴ This also was the situation with the case presented here.

Case Report

History and Chief Complaint

This female patient was treated at the University of Iowa College of Dentistry. She presented to the author in the Operative Dentistry department as a 15-year-old with fair oral hygiene, moderate dental fluorosis, and moderate maxillary and mandibular anterior teeth crowding. She was in good general health with an unremarkable medical history.

The patient had been a regular patient at the College of Dentistry in the Pedodontic Department since the age of 4 years. At the age of 9 years 10 months, she was brought to the pediatric clinic with approximately one-half of the incisal portion of the clinical crown of tooth No. 9 (maxillary left central incisor) fractured off. She reportedly “fell down icy stairs 1 hour ago.”

A periapical radiograph (Figure 2) was made, and after local anesthesia and rubber dam isolation, the treatment performed was a Cvek type pulpotomy¹⁵ using calcium hydroxide (CaOH2) powder and a resin-modified glass ionomer (RMGI). Reattachment of the fragment was then performed using a 4th-generation dental bonding system and a microhybrid composite resin. The parents were informed of the prognosis and that additional pulp therapy may be needed in the future.

The patient was seen for postoperative evaluations at approximately 1, 2, and 5 weeks. She reported sensitivity breathing cold air for the first day, after which no further symptoms were reported. The tooth was re-evaluated regularly during the patient’s normal recall visits, with normal pulpal response and no evidence of pathosis. Apexification was successful, and a dentin bridge formed over the exposed pulp area, as shown in the 5-year postoperative radiograph of the first reattachment (Figure 3).

The history of the reattached tooth was non-episodic for 5 years and 9 months, until a second injury re-fractured the same tooth. The patient reported that “she bumped her tooth on a friend’s knee,” and the tooth broke again.

Retreatment

The patient presented to the author 10 days after the second injury (Figure 4). She had reattached the tooth fragment with superglue the same day as the second injury and it was still intact. A periapical radiograph (Figure 5) was acquired, and a lingual matrix was fabricated with a heavy-body polyvinyl siloxane while the tooth was still intact. This was done by holding the left index finger lingual to the maxillary incisors and injecting Template Matrix Material (Clinician’s Choice Dental Products, Inc., www.clinicianschoice.com), filling the space between the operator’s finger and lingual surface of the teeth. The tooth (No. 9) tested within normal limits to pulp testing, so local anesthesia was given before rubber dam application. The tooth fragment was removed easily with a spoon excavator by using scaling movements at the lingual fracture margin. Figure 6 shows the remaining CaOH2 over the dentin bridge formed after the first reattachment.

The tooth segments were treated with microabrasion with 50-micron aluminum oxide to prepare the surfaces for rebonding and to remove the residual superglue. The bonding surfaces were treated with 37% phosphoric acid etchant for 10 seconds on dentin and 20 seconds on enamel. Then a 4th-generation dental bonding adhesive (DBA) (OptiBond™, Kerr Corporation, www.kerrdental.com) was placed on both the tooth and tooth fragment. First, the primer was lightly scrubbed on the dentin surfaces for 20 seconds, then air-dried. Next, the adhesive was applied with a microbrush for 10 seconds, then thinned out with the microbrush; but it was not polymerized with the curing light until after the tooth fragment was in position.

The 4th-generation DBA was chosen because of its proven clinical performance as the gold standard in dental bonding. The most effective adhesives are the ones where the primer and adhesive remain separate until placed on the tooth. Another bonding technique showing much promise is the 6th-generation adhesives with selectively pre-etching the enamel only¹⁶ described by Van Meerbeek et al.¹⁶ In light of the 2010 Van Meerbeek study, the author recommends using a mild 6th-generation DBA with selective pre-etching of enamel when large amounts of dentin are involved in the fracture.

A dual-cure resin cement (Calibra^® Esthetic Resin Cement, DENTSPLY International, www.dentsply.com) was used as the luting agent because it has an ultra-low film thickness (12 μm to18 μm), and working time was flexible, which provided convenience and accuracy for positioning of the fractured tooth portion with the lingual matrix. With the lingual matrix holding the fractured tooth portion in position, the excess luting cement was removed with an explorer and a dry microbrush because of the loss of marginal enamel, and characterization with paste composite would be needed. However, if no tooth structure is missing, a wetted microbrush is recommended to prevent pull-back of the resin from the margins.

After the excess was removed, the resin cement was cured with an LED curing light and the lingual matrix was removed. The facial margin was open—due to the loss of marginal enamel at the time of re-fracture—so a large scalloped bevel (2 mm to 3 mm) was placed with a diamond bur. Next, the beveled area and the new mesial-incisal angle fracture were etched for 30 seconds with 37% phosphoric acid, and rinsed and dried thoroughly. Then, the same 4th-generation DBA adhesive was applied in the same manner as above and light-cured for 20 seconds, then filled using a nano-filled, multi-shade, composite resin system (Filtek™ Supreme Plus, 3M ESPE, www.3MESPE.com).

After the final layer of composite was placed, the tooth, fragment, and restoration areas were light-cured—with the light tip perpendicular to the tooth surface—three 20-second times, overlapping to ensure complete polymerization; this process was repeated for the lingual surface as well.

Of interest is that the force that fractured the original reattachment also fractured the mesial-incisal corner of that same tooth (Figure 7). This is a testament to the bond strength that the original repair had and how much force it took to re-fracture the tooth.

Finishing was done with contouring and finishing discs (Sof-Lex™ XT, 3M ESPE). This was done in progression from the coarse to the fine grit discs with the abrasive side mounted towards the slow-speed handpiece using a light “touch-and-go" painting fashion while flexing the disc against the tooth/restoration surface to avoid excessive removal of restorative contours. The author prefers discs to finishing burs whenever access allows because burs can leave chatter marks where smooth surfaces may be desired, and discs work very well in thinning the composite resin to a “disappearing margin” so that the composite finishes flush with the enamel surface. However, diamond and carbide finishing burs can be very useful when surface texture is desired. The polishing stage was performed with diamond-impregnated rubber polishers (HiLuster, Kerr Corporation), again with a light “touch-and-go" motion with low to medium speed to prevent excess heat generation. The final polish was done using FlexiBuff discs (Cosmedent, www.cosmedent.com) and Enamelize™ aluminum oxide polishing paste (Cosmedent).

The final polish was accomplished with a composite polishing paste applied with felt-type polishing wheels. Figure 8 shows the immediate postoperative result of the re-reattachment. Note that the rubber dam dehydration makes the restoration appear too dark.

Follow-up

At the regular 6-month maintenance visit, the tooth was still intact and the patient reported she had only 2 days of cold sensitivity postoperatively, after which everything “felt normal.” The operator was unhappy with the appearance of the mottling (Figure 9), so the following procedure was performed as a touch-up: shallow ditching (1/3 mm to 1/2 mm) with a 330 high-speed bur; the etching and adhesive procedure was performed using the same methods and materials used originally. An opaquer (Kolor + Plus^®, Kerr Corporation) was brushed into the ditched areas, then covered over with the same material used originally. After using the above-described finishing and polishing technique, the esthetic results were deemed more acceptable.

At the 1-year maintenance visit, the patient reported that everything was fine, and the tooth vitality test results were all within normal limits. A touch-up (using the same procedure as described above) was done to add mottling to the mesial incisal portion of the tooth to the satisfaction of the operator and the patient (Figure 10). At 14 months post re-reattachment, a periapical radiograph was taken to verify that there was no pathology prior to commencement of orthodontic treatment (Figure 11). The orthodontist had been given the full dental history of the patient before the orthodontic treatment was initiated, so caution would be used, with debonding forces placed on the tooth in order to prevent re-fracture of the tooth.

Figure 12 is a photograph taken at the 4.5-year post re-reattachment recall, which was almost 10 years after the first injury/reattachment occurrence. It shows that the tooth is still intact following orthodontic treatment. At the most recent and 5-year recall of the second attachment procedure, the tooth was still intact and exhibiting normal pulp function and health.

Conclusion

In conclusion, the reattachment of tooth fragments can be a very successful treatment option for many patients who have had traumatic injury. With the use of proper techniques and materials, good long-term results can be achieved, and in some cases, tooth fragments can be reattached after a repeat injury to the tooth has occurred.

About the Author

Michael R. Meharry, DDS, MS
Associate Professor of Restorative and Esthetic Dentistry
Loma Linda University School of Dentistry
Loma Linda, California