Direct Resin Bonding for Successful Treatment of Class IV Fractures: Case Report

For the patient who presents with severely fractured anterior teeth, the dental clinician must decide whether to restore utilizing direct or indirect restorations. Full-coverage porcelain crowns have long been a popular treatment; however, direct composite restorations can offer several advantages. The primary advantage is the concept of being minimally invasive in order to preserve as much tooth structure as possible. This is especially important when restoring teeth in adolescents or young adults who are continuing to grow, or when pulp health is in question.¹ This preservation allows more and better future treatment options, if necessary.²
Aesthetics that mimic nature is also possible with today’s modern composite systems.^3,4 These systems allow the skilled clinician to build up restorations in layers, much like a master ceramist builds up porcelain, in order to achieve polychromatic restorations that blend with natural tooth structure. Having complete control, the artistic dentist can create restorations in one appointment that can rival the best ceramics, which is very advantageous, especially if good lab support is not available. These direct-bonded restorations are also long-lasting and are now considered a first- line restoration.^5,6
This article describes the clinical steps involved in restoring class IV fractures after a traumatic accident.

CASE REPORT

History and Chief Complaint

Figure 1. The patient presented to the office after a sledding accident. He was afraid he would never smile again.	Figure 2. Postoperatively, the patient is thrilled to have his smile back.

A healthy 14-year-old male presented to the office as an emergency. It started with a call that clinicians hate to get, especially on a busy day. “My son broke his front teeth in a sledding accident last night, and it is really bad. I found you on the Internet. Can you please help us?” And of course you say, “Sure, come on in and we’ll work you in.”
Israel presented with 3 fractured teeth and facial abrasions, but was thankfully not in any pain (Figures 1 and 2). However, Israel, along with both grandparents and parents, was an emotional wreck. They all doubted that Israel would ever be able to smile again. Past dental treatment had consisted of only routine hygiene visits.

Clinical Examination

Figure 3. Class IV fractures did not involve the pulp.	Figure 4. Natural-looking completed restorations.

The clinical evaluation revealed severe class IV fractures of teeth Nos. 7 to 9 (Figures 3 and 4). These were enamel-dentition fractures that did not involve the pulp, but all were very close, especially Nos. 7 and 8. The teeth were “sensitive to air,” but otherwise asymptomatic. No tooth mobility was noted, and the periodontal health was excellent. Intraorally, there were no abrasions or lacerations. Extraorally, the lower lip exhibited moderate abrasions. Radiographic examination revealed 3 fractured teeth with no evidence of any radicular or bony fractures.
The patient had no tenderness to palpation of the temporomandibular joints, maxilla, or mandible. Mandibular range of motion was within normal limits with no deviations or joint sounds. The joints could be loaded without pain or tenderness. An occlusal exam revealed a class I occlusion with canine guidance.

Clinical Procedure

The immediate concern was the pulpal health of the fractured teeth. Considerable dentin was exposed to the oral environment, with near exposures necessitating the sealing of the dentin as soon as possible. Furthermore, this was an emergency situation with no time to definitively treat the fractured teeth. After the patient was anesthetized, the fractured dentin and enamel were cleaned with a slurry of pumice and 0.12% chlorhexidine. Ultra-Etch 35% (Ultradent Products) was applied to the area and slightly agitated for 15 seconds. This was rinsed well and then lightly dried but not desiccated. Prime & Bond NT (DENTSPLY Caulk) was then applied with a brush, keeping the area saturated for 20 seconds. The acetone was evaporated by air-drying, and the area was light-cured. Renamel hybrid composite (Cosmedent) in shade A-2 was then placed over the exposed dentin in a thin layer of about 1 mm and light-cured. This “bandage” would act to seal and protect the dentin effectively. Diagnostic impressions using alginate were now possible without causing discomfort, and the patient was scheduled for treatment the next day.

Figure 5. Wax-up completed to final contours.	Figure 6. Putty matrix tried in before any preparation.

The treatment plan of choice was to restore the class IV fractures with direct bonded composite. This treatment would benefit this young patient because it could be carried out with minimal preparation, yet still restore the structural strength needed. Due to the severity of the fractures, any of the teeth could require endodontic treatment in the future, and more aggressive indirect restorations could always be done later in adulthood, if necessary. The author also felt comfortable delivering direct bonded restorations that would meet the family’s high expectations for naturallooking aesthetics.
Before the patient’s next appointment, the models were mounted on an articulator, and a diagnostic wax-up of the fractured teeth to desired final contours was completed (Figure 5). A putty matrix (Sil-Tech  [Ivoclar Vivadent]) was then fabricated over the wax-up to index the incisal edge and the lingual anatomy that were in harmony with the patient’s occlusion (Figure 6).
In order to mimic the lost natural tooth structure, accurate shade selection and color mapping was crucial. This had to be done first before the teeth could dehydrate. The polychromatic nature of Israel’s teeth dictated using several layers of differing composite, with some mimicking the lost dentin and others the lost enamel. With differing levels of translucency, opacity, depth of color, and internal and external characterizations, a unique custom build-up was required. We are fortunate to have many composite systems available that the skilled clinician can utilize to achieve this. The Renamel System (Cosmedent), which is a Vita-based system, was chosen for this case.

Figure 7. The layering sequence to be followed to achieve aesthetic results.

The basic body enamel shade was selected first using the Vita Classic shade guide (Vident) and a digital spectrophotometer (Vita Easyshade [Vident]). This was an A-2 shade. Next, an incisal value enamel shade was selected, which was Incisal Light shade. These shades were temporarily light-cured over the tooth without an adhesive to verify good shade match. By varying the thickness of these enamel shades, the position and shape of the dentin lobes, the amount of internal deep translucency, and the tints and opaquers, a realistic result could be obtained (Figure 7).
Since this was mostly an additive procedure, preparation was kept to a minimum. After anesthesia, a long, scalloped facial bevel was created with a tapered diamond bur (LVS3 [Brasseler]). Because of the large nature of the fractures, this bevel was 3- to 4-mm wide and extended from the dentin-enamel junction. The margin of the bevel was rounded because the composite was going to be carried onto the unprepared enamel surface to take advantage of as much enamel-adhesive surface as possible. A small 1×1-mm chamfer was placed in the palatal enamel. All enamel surfaces and the “composite bandage” were then cleaned with a pumice slurry in a prophy cup and then sandblasted with CoJet (3M ESPE), which is a silane-impregnated silicon dioxide. This served to increase bond strengths by removing the aprismatic enamel and enhancing the micromechanical and chemical retention between the “composite bandage” and the new composite.⁶

Figure 8. The lingual shelf is built up against the putty matrix to form the incisal edge, proximal contacts, and lingual anatomy.

The teeth were built up with composite one tooth at a time, beginning with tooth No. 9, then No. 8, then No. 7. Retraction cord (Ultrapak 00 [Ultradent Products]) was placed around each tooth in turn, and the tooth was isolated with Teflon tape (plumber’s tape). The teeth were acid-etched, and the bonding adhesive was placed as previously described. The Teflon tape was removed, and the putty matrix from the wax-up was positioned into place. Using a No. 8A composite instrument (Cosmedent) and a No. 1 sable artist’s brush (Cosmedent), a thin layer of about 0.3 mm Occlusal White hybrid resin was sculpted against the palatal aspect of the matrix from the facial-incisal line angle to the lingual chamfer on the tooth (Figure 8). The incisal portion was slightly thicker to form an opalescent halo. This layer forms the “lingual shelf,” which is a 3-dimensional framework that includes the incisal edge and the proximal contacts. This was light-cured for 20 seconds, as was each subsequent layer.

Figure 9. The artificial dentin layer is being sculpted into place.	Figure 10. A very translucent hybrid is placed between the dentin lobes to create some deep incisal translucency.
Figure 11. To block out the fracture line, a thin layer of opaquer is placed over the transition line.	Figure 12. The first layer of artificial enamel (in a microfill for its polishability) is placed.
Figure 13. A flat sable brush works well to smooth and remove any voids.	Figure 14. The line angles and long axis of the teeth are marked with a pencil to help establish symmetry in the primary anatomy.

The next layer, the artificial dentin in a hybrid A-2, was sculpted from just over the bevel to the incisal area, where it was shaped into dentin lobes with a contouring instrument (Cosmedent; Figure 9). This was followed by Renamel Hybrid Occlusal Clear, which was placed between the dentin lobes and under the incisal edge (Figure 10). This acts as a translucent effect enamel and forms a deep internal incisal translucency. To mask the fracture line and ensure a seamless transition from the tooth to the restoration, a thin layer of Creative Color Opaquer A-2 to A-2.5 (Cosmedent) was painted over the transition line with a No. 1 artist’s brush (Figure 11). Internal white effects were created by diluting some White Creative Color Opaquer (Cosmedent) and lightly painting the effects over small areas of the artificial dentin layer. The artificial enamel was created by first sculpting Renamel Microfill in an A-2 from the cervical area and feathering it into the incisal one third of the tooth (Figure 12). A No. 4 artist’s brush works very nicely to create a smooth surface (Figure 13). The final enamel layer was Renamel Microfill Incisal Light, which was sculpted to bring out the final contour from the incisal edge, feathering it into the body enamel layer and smoothing it with a No 4 sable brush. The entire restoration was then covered with an oxygen-inhibiting gel (K-Y Jelly [Johnson & Johnson]) and light-cured for 60 seconds from the facial and the lingual.
The finishing and polishing is a critical step in achieving a natural-looking restoration and improving the long-term durability.7 Before beginning to build the second restoration, the establishment of the primary anatomy or basic contour of tooth No. 8 was initiated using Sof-Lex Pop-On  Extra Thin finishing discs (3M ESPE). A pencil line was drawn along the facial-incisal line angle of the incisal edge as a reference, and remained untouched, since it was defined accurately by the putty matrix. The facial, cervical, middle, and incisal profiles in 3 planes were obtained. The mesial proximal surface was finished completely with a succession of finishing discs (FlexiDisc [Cosmedent]) and strips (Epitex [GC America]) so that the adjacent proximal surface on tooth No.8 could be built directly against it using the mylar strip “pull through” technique.8 All this was repeated until the 3 teeth were built up.
At this time, line angles and the long axis up the teeth were marked with a pencil for reference (Figure 14). The line angles and facial embrasures were then refined with discs to create the desired virtual width and ensure symmetry in the light-reflecting and light-deflecting areas. The incisal embrasures also were refined with finishing discs. VisionFlex discs (Brasseler) are really nice for developing these incisal embrasures.

Figure 15. Restorations are finished and polished to match texture and luster of the patient’s natural teeth.

The secondary anatomy, consisting of lobes and developmental grooves, was then placed using a No. 7901 12-fluted carbide finishing bur (Brasseler). Tertiary anatomy (surface texture) to match the natural teeth was created with a fine-grit flame-shaped diamond (F888 012 [Axis]) at low speed in a light horizontal sweeping motion. The high points of this texture were then smoothed with rubber polishing cups and points (Flexi-Cups, Flexi-Points [Cosmedent]). The final finish was created with Enamelize Polishing Paste (Cosmedent) on a felt disc (FlexiBuff [Cosmedent]; Figure 15).

CONCLUSION

Figure 16. Restorations demonstrate polychromicity.	Figure 17. The final results blend seamlessly with the natural teeth.

Restorative dentists are fortunate today to have resin-bonding systems available that allow the predictable achievement of beautiful aesthetics with predictable long-term results. The additive nature of this adhesive technology is ideal when the maximum preservation of healthy tooth structure is desired. This article describes a clinical technique for the conservative restoration of fractured anterior teeth in a young patient with direct resin restorations (Figures 16 and 17). The artistic nature of this treatment is very rewarding for the restorative dentist and pleasing for the patient.

References

Dr. Arnold graduated from the University of Kentucky College of Dentistry and completed a general practice residency at the Wright-Patterson Medical center in Dayton, Ohio. He has maintained a private practice for over 20 years in Lexington, Kentucky, concentrating on comprehensive restorative dentistry. He is an Accredited Fellow of the American Academy of Cosmetic Dentistry. Dr. Arnold currently serves the AACD as an Accreditation and Fellowship Examiner and as a board member of the American Board of Cosmetic Dentistry. He can be reached at fred@lexingtonsmiles.com.