Comparative evaluation of fracture resistance of re-attached teeth using self-adhesive bioactive flowable composite after preconditioning the fractured coronal fragments with different remineralizing agents

Introduction

Fracture of the crown of anterior teeth is one of the most common types of dental trauma that primarily affects adolescents and young adults. The location of upper incisors and their pattern of eruption brings a major risk for the dental trauma.¹ Dental trauma is more prevalent in case of contact sports, road traffic accidents, outdoor events, and in case of falls. Orofacial trauma comprises about 5% of all injuries to the body, while traumatic dental injuries (TDI) has been reported 15.2% prevalent worldwide.² With a prevalence of 17% to 48%, fractures of uncomplicated crown are the utmost or frequent types of dental trauma. 18–22% of all traumatic injuries to the hard tissues of dental origin result in fractures of the coronal portion of permanent upper incisors, and 96% of them involves the upper incisors (80% of them are central incisors and 16% of them are lateral incisors). Injuries caused by dental trauma not only affects the dentition, but also have a major impact on psychological status of the patient. According to the International Association of Dental Traumatology reattachment of the fractured fragment is the best method to restore uncomplicated fractures of the crown of permanent teeth, if the fractured fragment is available.³ Many of these problems have been resolved because of the advancement in field of bonded aesthetic dentistry and its ongoing evolution. A better prognosis can result by using intermediate composite material and the lack of further added preparations, which can improve the adhesion of fractured fragments. Although composite restorations of direct and indirect type and prosthesis are other treatment options, but fragment reattachment has been proven to be a preferable alternative for restoring aesthetics, improved functions and natural anatomy of the tooth. In Addition to this, it is cost-effective and time-saving.⁴ Because the general anatomical shape of the tooth, colour, and texture of the tooth surface are preserved, reattaching the fragment can produce pleasing aesthetics that last for a long time. This procedure is rather simple and fairly conservative. It restores tooth function and encourages the patient to feel better immediately on an emotional and social level.⁵ If another traumatic incident occurs or when the restored teeth are used in a way that is not physiological, the reattached fragments are vulnerable to breaking again. The resistance of the fractured teeth that has been reattached is the subject of the majority of concerns. The significant factor is whether the fragment of fractured tooth and the residual tooth can form a stable, predictable union. Activa bioactive has rubberized resin component having more fracture resistance and shock absorption and being a smart material adapts to PH cycle. It has all the desired properties such as improved hydrophilicity, sealing ability, bond strength. Activa Bioactive Flowable Composite is designed for a broad range of restorative applications, leveraging its unique combination of bioactivity and flowability. Its clinical indications stem from its ability to release calcium, phosphate, and fluoride ions, promoting remineralization and reducing secondary caries risk, making it particularly suitable for high caries risk patients, deep cavities, and those with xerostomia. The flowable consistency facilitates use in various cavity classifications (I-V), pit and fissure sealants, liners/bases, and repair of enamel or existing restorations, aligning with minimally invasive dentistry principles. Its moisture tolerance and shock-absorbing properties further expand its utility, especially in geriatric and pediatric dentistry, and in situations where traditional resin materials might be contraindicated due to allergies or biocompatibility concerns. Additionally, its dual-cure nature and ability to bond to tooth structure make it suitable for fracture reattachment, providing a bioactive and durable repair. The conventional flowable composite clinically used in dentistry for reattachment varies in terms of bond strength and adhesion therefore newer materials with improved properties are desired and henceforth in this study the material Activa bioactive will be tested. The hydration status of the fragment significantly influences the successful reattachment of a fractured tooth fragment. Dehydrated fragments exhibit decreased fracture strength and may discolour. Studies demonstrate a wide range of fracture resistance in reattached teeth, with hydration emerging as a crucial factor. Rehydrating fragments before reattachment significantly improves fracture resistance, as evidenced by increased strength in both hydrated and rehydrated groups compared to dehydrated ones. Hydration prevents collagen fibre collapse in the dentin, enhances bond strength, and maintains aesthetic appeal by minimizing discolouration. The time interval between the traumatic injury and reattachment as well as the hydration of the broken fragment, which preserves the vitality and original shine of that of the natural tooth, are the major factors in the achievement of re attachment of fractured fragments. Dentin moisture is necessary to fortify the binding between composite resin and dentin. According to findings from the literature, hydrated fractured tooth fragments have a stronger bond than dehydrated pieces.⁶ For preconditioning of the fractured fragments use of remineralizing agents not only may aid in hydration but also for up taking maximum of the mineral ions like calcium and phosphate. But, the study about the result of remineralizing agents affecting the bond strength of re attached tooth is limited. Henceforth, a study will be done to assess the fracture resistance of the teeth that is reattached using self- adhesive bioactive composite and were pre-treated with remineralizing agents such as sodium fluoride, casein phosphopeptide–amorphous calcium phosphate (CPP-ACP), prior to re-attachment.

Objectives

Methods

Discussion

The task is to handle the tooth with utmost care that further lessen the damage of the teeth with coronal fractures of upper incisors. Several restorative techniques of direct and indirect type are in use for the treatment of fractured teeth, although such techniques often compromise a lot of the natural healthy tooth structure.⁹ If there is only a slight violation in the area of the biological width and a complete fragment of the fractured tooth is available, the re attachment of the fractured fragment method can be considered. Bruschi-Alonso et al. stated that the first choice of treatment for fractured tooth having uncomplicated crown fracture should be the re-attachment of fractured fragment.¹⁰ Reattachment offers many benefits over other procedures as it is a minimal invasive in nature, uncomplicated, and cost-effective process. It aids in maintaining enduring aesthetics and is highly accepted by the patient.

Hydrating fragments of fracture play a significant role in improvement of the resistance of fracture at re-attachment interface.^4,11 Time interval during or after trauma, media that is used for storage, and dry time before the re-attachment of the fractured fragments are crucial aspects and they impact the resistance of fracture and adhesive strength of re-attached fragments. Most commonly affected teeth by dental traumatic injury are maxillary central incisors. Hence maxillary central incisors are selected for the study. In regard to the method used, the fragments of tooth will be attained by segmenting with a diamond disk in spite of fracturing. Instead of fracturing the teeth, fragments will be carefully sectioned with a diamond disk to ensure a controlled and reproducible fracture surface for the study. Badami et al. and Reis et al. stated that the tooth surface that is sectioned is totally different from that of a tooth surface that is fractured.¹² The path of the fractured line in case of a tooth that is sectioned is indicated by the position of the disk, it inclines to run in a direction parallel to the direction of prisms of enamel in a region of fragmentation. In a while, because trauma has a nature of not proceeding linearly or with good adjustment, this direction may not correctly depict the accurate circumstances of the trauma. To minimize confounding bias and ensure standardization of the fractured surfaces, a diamond disk will be used to simulate the fracture, thereby achieving consistent fragmentation. According to Garcia et al. and de Souza et al., fractured fragment is reattached by a technique of no preparation and a bonding system having intermediate resin composite comprising good mechanical properties that have the capacity to restore part of the resistance of the tooth that is fracture.¹³ Preconditioning of fractured fragments with remineralizing agents may aid in hydration. Thus, this study will evaluate the fracture resistance of reattached teeth pretreated with sodium fluoride or casein phosphopeptide-amorphous calcium phosphate and bonded with a self-adhesive bioactive composite.