Tooth Fragment Reattachment: Interim or a Permanent Solution?

Abstract

One of the most commonly encountered situations in clinical practice is dental trauma. Children and adolescents frequently report with uncomplicated/complicated crown fracture that requires immediate consideration. Clinicians should be prompt in treating such injuries and must be aware of the various treatment options available. With the advent of newer adhesive systems, reattachment has become the treatment of choice when the fragment is properly stored, and luxation injury is not associated with the fracture. This article aims to review the various techniques available for reattachment of fractured fragment and the recent advances in the adhesive systems.

Introduction

Injury to the oral region comprises of around 5% of all physical injuries ¹ and about 92% of patients seeking consultation for oral injuries report with traumatic dental injuries (TDIs). Most commonly reported dental injury is crown fracture in the maxillary anterior teeth especially in preschool children and adolescents.^{2, 3} TDIs have physical, psychological, and social impact and, in general, affect the quality of life of patients. Therefore, dental injuries necessitate an emergency intervention and management that should aim at restoring function and aesthetics of the fractured tooth.

Management of crown fracture depends upon a number of factors; type of fracture (complicated/uncomplicated), degree and pattern of fracture, age of the patient, and stage of tooth eruption. ⁴ Several treatment options are available for the restoration of fractured tooth including full coverage crowns, post and core, and composite restorations. With the advent of newer adhesive systems, tooth fragment reattachment, which was earlier considered as an interim restoration, ⁵ has evolved as an established treatment modality. ⁶

Fragment reattachment was first reported in literature in 1964 by Chosack and Eidelman. ⁷ Some authors propose “simple reattachment” ⁸ with no additional preparation while others have proposed a variety of preparations for the reattachment of fractured fragment.^9–13 In 1982, a “V-shaped, notched bevel” preparation was employed to restore a fractured central incisor using acid etch technique and microfilled composite resin. ¹⁴ This technique is popularly known as Simonsen’s technique. Several modifications in the technique have been developed over the time. A modified Simonsen’s technique was proposed, in which “notches” were prepared on the proximal surfaces of both the fragment and the remaining crown. These notches were meant to guide the correct adaptation of the tooth fragments. ¹⁵ These modifications aim to increase the longevity of the restoration while maintaining the aesthetics and function of the reattached fragment.

With the advancements in the adhesive technology, minimally invasive technique has evolved and progressed in every aspect of dentistry. Historically, clinicians relied upon conventional cements ⁷ and interlocking minipins ¹⁶ for reattachment of the tooth. In 1974, Tennery ¹⁷ reported tooth fragment reattachment using acid etch technique. Shortly after that, use of bonding agents for micromechanical retention became widespread.^{18, 19}

Advantages

Tooth fragment reattachment is indicated when the fractured segment is available and there is minimal or no discrepancy in the fit between the fractured segment and tooth. ¹⁵ This technique has many advantages:

The original color, contour, and texture of tooth is preserved.

It is a highly conservative procedure that requires little or no tooth preparation.

Wear rate of the incisal edge is same as the adjacent tooth, compared to composite restoration, which abrades at a faster rate. ¹⁴

The procedure is rather simple, requiring less chair-side time.

Patient presenting with TDIs suffers from negative psychological impact. Reattachment provides rapid outcome thereby, imparting an overall sense of optimism and confidence.

It is a relatively inexpensive procedure compared to other comprehensive treatments.

Techniques for Fragment Reattachment

What began as a simple “fixing” procedure by rejoining with conventional cements, ⁷ tooth reattachment has evolved into a recognized treatment option with exceptional and consistent outcome.^20–22 Since it was first reported in 1964, ⁷ several modifications in the tooth reattachment have been proposed. Although there is no established consensus as to which technique yields best result, some techniques do offer advantage over others.

1. 1.

Simple reattachment: It involves reattachment of the fragment without any additional preparation of either tooth or the fragment. This technique can be applied in cases where the fractured segment and tooth fit together completely without any discernable disruption between the segments. ²³ It has been shown that reattachment without any additional preparation recovers only 50% of the fracture resistance as compared to a sound tooth. ²⁴ Srilatha et al ²⁵ have reported a fracture strength recovery of around 36.6% compared to a sound tooth in simple reattachment technique which suggests that this technique results in a fracture strength of even less than 50% of a sound tooth. On the contrary, Worthington et al ²⁶ reported no difference in the bond strength in teeth reattached with simple technique compared to those with additional preparation. It a relatively noninvasive procedure and has an advantage of providing superior esthetics. ²⁷

2.

Enamel bevel: Proposed by Simonsen in 1979, ⁹ this technique involves preparation of a 45° bevel circumferentially on enamel margins of both, fragment and the tooth. The author proposed that during beveling, minimal enamel is removed, and the prepared surface shows an ideal end on relationship of enamel prisms for optimum etching and bonding. However, a study conducted by Dean et al ²⁸ concluded that there is no significant difference in retention between enamel bevel preparation and simple reattachment. According to Simonsen, ⁹ this technique offers superior aesthetic as the fracture line is concealed behind layer of composite. This assertion was disproved by Simonsen in 1982, when he proposed internal enamel groove preparation as the band of composite on the labial surface showed discoloration over time. Other drawback is the loss of precise fit of the fragment because the preparation is done prior to the reattachment.

3.

V-shaped internal enamel groove: This technique was also proposed by Simonsen in 1982 to overcome the drawbacks of previous method. ¹⁴ In this procedure, an internal V-shaped notch bevel is prepared inside the labial enamel of both tooth and fragment while keeping outer enamel surface intact. Simonsen advocated preparation of a conventional 45° bevel on the palatal surface (~1 ½ mm). However, many authors proposed preparation of a V-shaped internal groove all the way around the tooth. Reis et al ¹² have reported an increase in the bond strength by 60%, as a result of beveling or preparation of an internal enamel groove before reattachment compared to a simple reattachment. Since the preparation is done before reattachment, loss of fit of fractured fragment may still be seen.

4.

Internal dentine groove: It involves preparation of a dentinal groove (1 mm deep × 1 mm wide) in the fractured fragment and tooth before reattachment. Srilatha et al, ²⁵ in a study comparing 4 different reattachment techniques, have reported that internal dentine groove has shown to attain a fracture strength recovery of 89.2% in relation to a sound tooth. The superior fracture resistance is attributed to the increased area of adhesion and the additional resin infiltration in the groove which acts as an opposing force to the compression load. According to Diangelis and Jungbluth, ²⁹ preparation of an internal dentine groove provides increased bond strength and inhibits the eventual darkening due to devitalization of dentine in the fragment. However, the composite resin exposed to the oral cavity undergoes discoloration and abrasion over time with resultant aesthetic loss. ³⁰

5.

External chamfer: This technique was proposed to overcome the problem of loss of fit due to prebonding preparation techniques. In this technique, a chamfer is created along the fracture line after the reattachment procedure. Abdulkhayum et al ³¹ have reported a fracture strength recovery of 60.3% in relation to a sound tooth compared to simple reattachment technique which shows a fracture strength recovery of 44.3%. Yilmaz et al ³² evaluated success of fragment reattachment using “V-shaped double chamfer” technique. None of the cases reported with fragment detachment at 24 months follow-up. The author attributed the high success rate to the use of flowable composite resin and reinforcement of the fracture line with double chamfer technique. It allows for better reapproximation of the fragment and the tooth. ²⁴

6.

Overcontour: This technique involves preparation of a groove along the fracture line extending coronally and apically after reattaching the fragment. Srilatha et al ²⁵ have reported a fracture strength recovery of 91.4% compared to a sound tooth, highest among all the above-mentioned techniques. Likewise, Reis et al ¹² have reported the highest fracture strength recovery of 97.2% compared to sound tooth with composite overcontouring. ¹² This has been attributed to the increased adhesion area which allows greater delivery of composite on the tooth that promotes a more favorable distribution of forces in the enamel. However, the gradual loss of aesthetics due to abrasion of resin over time has been reported. ²⁷

7.

Vertical groove: This is a relatively new technique in which 2 vertical grooves of 2-mm depth and width are prepared on the labial surface of the tooth after reattachment. ³³ The grooves accommodate fiber-reinforced composite posts placed extracoronally to aid in the retention of the fragment. Karre et al ³³ have reported fracture strength recovery of 62% in relation to a whole tooth with this technique. The placement of fiber post in the fracture site reinforces the adhesion thereby, increasing the fracture resistance.

Survival Rate of Reattached Fragment

With the advances in adhesive technology, fragment reattachment has evolved as a fairly reliable treatment option with consistent and predictable outcomes. Many cases with long-term follow-up have shown promising result in regard to the retention and aesthetics of the restored teeth.^{20–22, 34} In a multicenter study by Andreasen et al ³⁵ on 334 central incisors restored with reattachment, it was reported that 50% and 25% of the teeth remained intact after 5 years and 7 years of follow-up, respectively. In another study, 50 reattached teeth displayed 80% survival rate at 5-year follow-up. ³⁶ Apart from that, several authors have concluded that fragment reattachment could be considered as a viable treatment alternative for fractured teeth as a result of trauma.^{4, 6, 37}

Factors Affecting the Survival of Tooth After Fragment Reattachment

Several factors have been reported to affect the longevity of the fragment reattachment; reattachment technique, material used for reattachment, presence or absence of an intermediate material, and rehydration of the fragment prior to reattachment.

Many authors have recommended preparation of the fragment and/or tooth before reattachment^{9, 10, 14, 29} while others have proposed that preparation of the fragment and/or tooth does not affect the bond strength of the reattached tooth.^{8, 26}

Apart from the reattachment technique, the importance of material used for reattachment cannot be understated. Various bonding systems (multimodal, self-etch, total etch) and intermediate materials (traditional composites, flowable composite, or glass ionomer cement) have been used for fragment reattachment.^{6, 27, 30} Some authors emphasize that the technique used for reattachment is the primary factor affecting the bond strength rather than the material.^{12, 38} In contrast, many authors advocate that both the technique employed and the material used for bonding are primary factors affecting the bond strength of reattached fragment.^39–41 According to Bruschi et al, ²⁷ neither the technique nor the material alone could restore the fracture strength of tooth close to an intact tooth. However, association of proper technique and bonding system employed for reattachment could help achieve the impact strength of reattached tooth similar to that of a sound tooth. ²⁷ Farik et al ⁴² demonstrated that the type of adhesive system used directly influences the fracture strength of the bonded tooth. In another study, Pagliarini et al ⁴³ evaluated the effectiveness of existing adhesives in fragment reattachment. The author concluded that fourth-generation adhesives showed superior bond strength compared to fifth-generation adhesives. Likewise, Bruschi et al ²⁷ compared the impact strength of total-etch and self-etch adhesives and reported that strength achieved after reattachment with total-etch adhesives is significantly higher than the self-etch adhesives.

The use of light-cured, dual-cured, or self-cured luting cements, flowable composites, and conventional composites as intermediated materials have been proposed. Many authors have concluded that presence of an intermediate material does not have a direct influence on the impact strength of the reattached fragment.^{12, 27} However, Pusman et al ⁴¹ have reported that the type of adhesive used for bonding and the intermediate material affects the fracture strength of the tooth.

The storage of fragment prior to reattachment has also been shown to affect the bond strength of the tooth and the fragment. Farik et al ⁴⁴ reported that bond strength of reattached fragment is reduced if the fragment is held dry for more than 1 h before the procedure. The authors recommend storage in wet media for at least 24 h prior to reattachment if the fragment was held in a dry environment initially. ⁴⁴ In contrast to this study, Yilmaz et al ³⁷ have proposed that the storage media of the fragment does not affect the survival rate of the reattached tooth. In addition, Capp et al ²⁴ reported that fracture strength of a fragment that has been stored in a dry media for up to 48 h could be restored by keeping the fragment in a wet media for 30 min prior to the procedure. Another concern in relation to dry storage of the fragment is the color disharmony between fragment and the tooth. ¹⁴ However, at the 1-year follow-up, the tooth recovered its natural translucency. ¹⁴

Conclusion

Development in the field of adhesive has enabled clinicians to adopt minimally invasive procedures in the clinical practice. Fragment reattachment is a relatively simple procedure and can be opted as a treatment modality in fractured teeth. Several modifications in the preparation technique have been proposed. However, none of the techniques could restore fracture strength equal to that of an unrestored natural tooth. Nevertheless, implementation of proper technique and adhesive material could help achieve satisfactory outcome in terms of retention and aesthetics.