Tooth Fragment Reattachment: Interim or a Permanent Solution?

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.

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.

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

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.