Can A Fractured Cusp Be Repaired

An in-depth look at cusp replacement using composite, pins and polyethylene fibers

Introduction
This commodity suggests blending ii unlike techniques—titanium pins with high-strength polyethylene fibers—within one process. Using the different reinforcing architectures is beneficial to matching substrate backdrop and ensures retention of restorative material. They reduce stress and provide an even distribution of force throughout mastication.

Case written report No. 1
A 55-year-old male patient had chief complaints of a broken tooth and hypersensitivity in the mandibular lower right side. He also presented a fractured amalgam with a missing distobuccal cusp of the first tooth. He requested to have the restoration washed within ane engagement.

Materials, methods and results
To provide the acceptable strength to sustain the masticatory forces and fractures, a titanium pivot was inserted post-obit the adhesive procedures. To reduce microleakage, a composite was incrementally placed, with reinforcement of the polyethylene fiber layers well adapted between increments.

When the patient returned a yr later, the restoration was in very good condition. In this item situation, a directly reinforced blended restoration was the optimal choice because it may have some advantages over other conventional approaches.

Clinical significance
Posterior cavities needing a cusp replacement are usually treated with laboratory-fabricated onlays, direct/indirect restorations, or crowns. This case demonstrates firsthand cuspid reconstruction, optimizing the potential of direct posterior composite restorations. When used correctly, this has many advantages over other restorative methods.

For more than than 4 decades, composites take been used in posterior teeth; unfortunately, the initial clinical performance of the first posterior composites weren't ideal.ⁱ These days, composites have improved their concrete, mechanical and adhesive properties,² only habiliment and marginal leakage remain a business organisation.³ Recent long-term clinical evaluations demonstrate that composites are an acceptable alternative for posterior teeth inside sure clinical parameters.^4,five If clinicians are adequately skilled and familiar with well-nigh of the agglutinative dentistry secrets, then they volition extend the indication for direct restorations into a more destroyed tooth.⁶

The placement of a Class II blended restoration is often associated with undesirable furnishings of shrinkage such as an interfacial gap germination.^7,8 Sometimes, because of blended shrinkage, the cloth pulls abroad from the cavity wall during polymerization.^9,10 This may contribute to a microgap formation, which permits the entry of bacteria and oral fluid^xi,12 and results in hypersensitivity and staining of the margins and recurrent caries.¹³

Early investigations on the immovability of resin–dentin adhesion found decline over fourth dimension. Tooth–resin adhesion may degrade by chemical and physical stress.¹⁴ However, the mechanism of the decrease in bond strength was unknown until it was published in 2004. As a result of long-term exposure in a humid environment, the hybrid layer degrades, and the dentin–agglutinative resin bonds weaken.¹⁵ If in that location is a presence of sclerotic dentin, the bond forcefulness significantly decreases.¹⁶

A made indirect restoration laboratory (onlay or crown) is considered the treatment of pick when a cusp is lost.¹⁷ CAD/CAM technology tin also be practical for inlays and onlays.¹⁸ Both alternatives offer advantages and disadvantages, and both are complex and expensive treatments. Crowns are highly invasive, and tin be pricey every bit well. The full-coverage crown should always be the last handling option, because information technology is the most invasive and traumatic restorative process.¹⁹

Many crowned teeth could have been restored with less aggressive restorations.²⁰ Direct options such as blended or amalgam restorations are acceptable, with both being a single-engagement procedure and having a like prevalence in cusp fracture.²¹ Constructing has long history of apply with clinical success, and has been an effective restorative material for Class I and Class II preparations. Nonetheless, its use has declined because patients and clinicians preferred artful, agglutinative, mercury-gratuitous restorative materials.²²

Data supports that glass fiber-reinforced composite increases the fracture resistance of weakened marginal ridges in molar teeth.²³ Fibers also increase the harm tolerance of a tooth; they can exist used to provide additional back up to weakened cusps and to span cracks.²⁴ In applications such as cuspid reconstruction, multidirectional reinforcement can arrest cracks and forbid their propagation in the cervical direction.²⁵ Equally shown in literature, dentin pins increase shear resistance of extensive composite restorations.²⁶

Composite restorations may be the optimal choice because of their conservative grooming and aesthetics. Using pins and loftier-strength polyethylene fibers is some other alternative. They offer an efficient load distribution and also make its structure extremely touch on-resistant. This results in a successful aesthetic integration of the restoration.

In the late 1950s, the introduction of practical instrumentation utilize for stainless steel pins resulted in their extensive use in dentistry.²⁷ Pins in dentistry are indicated as additional aids of retention in badly broken-down or mutilated teeth. They are especially needed when one or more cusps need capping and when increased resistance and memory class are needed. With 5-twelvemonth-old amalgam fillings, at that place was no difference in the performance of pin-retained amalgam and bonded amalgam.²⁸

Fig. ane: A patient presents with a large amalgam Course?II failure in the mandibular first molar with a fractured distobuccal cusp. While an onlay or crown is probably the restoration of pick, a directly resin was chosen considering of the patient'southward fourth dimension constraints.

Fig. ii: The one-fourth dimension-use Max pin latch type came in a sealed plastic container. Place the pivot into a low-speed handpiece.

Fig. iii: All-Bail Universal primer from Bisco (10 micros) is applied to the Max pin.

Fig. 4: Rubber dam has been positioned afterward the constructing was removed. (Note the access to the gingival extent of the fractured cusp.) During the pin placement, utilize a very low speed and slight force per unit area down until the pin shears. This means the pin placement has been completed.

Fig. 5: Later on smoothing the preparation, every surface involved is sandblasted for a few seconds, giving it a matte expect. Selective-compose with phosphoric acid.

Fig. six: After applying an antibacterial solution, a generous amount of primer is scrubbed for thorough penetration onto the surfaces.

Fig. vii: Once the primer has evaporated with the assistance of slight warm air, the bonding agent is practical and thinned out.

Instance study No. 2
A 62-year-old patient in skillful general health presented with sensitivity in the right side of his mouth. The clinical exam revealed a mandibular right outset tooth with an all-encompassing amalgam fracture and a missing distobuccal cusp (Fig. 1). The process was performed with a rubber dam to achieve full isolation. This technique is essential²⁹ and no other isolation method provides better control over oral fluids and moisture contamination.³⁰

After completing the preparation of all internal angles, they must be rounded to reduce stress concentration³¹ and improve the adaptation of composite resin to the dental structure. No bevels were placed on the occlusal or gingival margins. It is suggested to utilise one pivot per missing cusp³²; in this instance, just ane was needed. Displaying plenty room from the base to the cusp tip (4mm) is crucial for the placement of the pin. Sufficient dentin is necessary to attain adequate strength to avoid external fractures of the molar construction and to protect the pulp. Once the channel location is decided, a pinhole guide is formed with a ¼-circular bur (slow speed) in dentin, 1.5mm on the external surface. The Max 021 organisation of pins from Coltene/Whaledent (Fig. 2) was used in this case.

Using a pilot drill, with a wearisome-speed contra angle, a pinhole was prepared until the drill shoulder came to a stop. The channel preparation was done to total depth and a pin was inserted into the handpiece and covered with primer agglutinative from Bisco (Fig. 3) while operating at very low speed with calorie-free pressure level until the pin sheared and the placement was completed (Fig. 4).

Every surface is microetched with 35 microns aluminum oxide (Crystal Air by Crystalmark Dental Systems). Two?percent chlorhexidine (Cavity Cleanser by Bisco) was used to disinfect the preparation and it was then dried with lite air. A selective-etch technique was chosen and phosphoric acid (Select HV Etch by Bisco) was applied on the enamel for 15 seconds (Fig. five, p. 86), then rinsed thoroughly and dried. And then, OptiBond XTR primer (Kerr) was practical by scrubbing with moderate pressure for thirty seconds (Fig. six, p. 86). The agglutinative from OptiBond XTR was used with gentle agitation for 15 seconds (Fig. seven, p. 86), followed by a warm air dry to sparse out the layer and evaporate the solvent.

A sparse 0.5mm layer of tacky thickened flowable blended (Ribbond Securing Composite) was placed onto the pulpal floor, which is of high opacity. The high-strength polyethylene fibers, past Ribbond (Fig. 8), were blotted with an unfilled bonding adhesive and the excess was removed with lint-free gauze. The polyethylene fibers were adapted and pressed equally close to the pulpal flooring every bit possible (Fig. 9), then light-cured.

In one study, it was found when fibers were inserted into the depth of the proximal box, lilliputian or no microleakage took place³³ and increased the microtensile bond forcefulness to the dentin in cavities with a high C factor.³⁴ Some other thin layer of composite was practical (Fig. 10) and the concluding buildup was done with a warmed filled restorative composite to increase immovability.³⁵ Tints (Kolor Plus by Kerr) were placed to create the anatomy and glycerin was placed on every surface (Fig. 11) and lite-cured for twoscore seconds on each side.

The rubber dam was removed, and the occlusion was inspected in all eccentric movements to avoid whatsoever premature contact (Fig. 12). The restoration was contoured and began spreading with intraoral polishing paste (DiaShine past VH Technologies) using a latch brush and keeping light in constant contact with the restoration (Fig. 13), to provide a college surface luster (Fig. 14). As a preventive measure out for occasional bruxism, the patient was provided a night guard.³⁶

Fig. eight: An application of a sparse layer of composite tacky flowable is placed. Then an end of an endodontic plugger was used to pick upwardly the polyethylene fibers (Ribbond) soaked in unfilled resin to enable their transfer to the grooming. The fibers are placed and pushed closest to the dentin flooring and extended slightly up the axial and proximal walls.

Fig. ix: Another polyethylene cobweb is practical and pressed with the end of the plugger in a different direction.

Fig. 10: After awarding of polyethylene fibers, adapted closely, without suffering pullback. In the stop they disappear into the composite. These fibers can increment the fracture toughness of the tooth and forestall dentin scissure propagation.

Fig. 11: After an enamel composite layer is placed, the anatomy is created. Glycerin is applied to all margins to preclude the formation of an air-inhibited layer. The restoration is light-cured on the facial, lingual and occlusal sides.

Fig. 12: Subsequently removing the safety dam, the occlusion is evaluated in every movement. The restoration is now contoured.

Fig. thirteen: A few weeks later, the patient came for examination. Intraoral polishing paste (DiaShine by VH Technologies) was used with a latch brush and kept continual contact with the restoration to provide a great surface end.

Fig. 14: Notation the splendid anatomical form and pleasing high surface luster.

Results
No retention or resistance was formed in the crenel preparation. The retention of the restoration relied on the adhesive technique, the titanium pivot³⁷ and the polyethylene fibers. It is of paramount importance to leave the restoration with enough strength to withstand an occlusal challenge, especially if the restoration is subjected to the same forces that initiated the original failure.

Conclusion
As oral health providers, we are always looking for the best handling techniques for our patients.³⁸ Advisedly combining pins and loftier-strength polyethylene fibers with first-class restorative textile can improve the long-term prognosis of a tooth. The results are a successful aesthetic integration of the restoration—and easy repair, if necessary.

In selected clinical situations, reparation is an advantageous and practical culling to a replacement and can significantly increase the lifetime of these restorations.³⁹ Cuspal coverage with direct posterior composite restorations may stand for a valid alternative to conventional indirect restorations. The data indicates that composite resin is a technique-sensitive restorative textile that tin can be used in large preparations, if proper manipulation and isolation can be maintained.⁴⁰ This requires an increased attending to detail, and the primary reason for failure over time would exist secondary caries and fractures.

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Dr. Isaias Íñiguez graduated from La Universidad Autónoma de Baja California and went on to complete a postgraduate programme in aesthetic dentistry from Baylor College of Dentistry in Dallas. Íñiguez was the get-go Latin American dentist accredited by the American University of Cosmetic Dentistry (AACD) in 1998; he continues to be the but accredited member of the AACD with a practice in United mexican states. Íñiguez is also an active member of the American Dental Association, the California Dental Association and the Asociación Dental Mexicana.