Clinical options for incisors replacement in children with dental trauma: a case report

1. Introduction

Dental trauma is prevalent across all age groups, with epidemiological studies indicating a higher incidence in children and approximately 15% of preschoolers and 20–25% of school-aged children experiencing dental trauma [1]. The maxillary central incisors are the most commonly traumatized permanent teeth, with their vulnerability increasing with greater anterior protrusion [2, 3, 4, 5]. These injuries not only affect the physical condition of the teeth but also have psychological and social implications for the child [6].

The incisors are crucial for aesthetic appearance, and if they suffer trauma, severe impaction, deformity or resorption, extraction may be necessary [7, 8]. Root resorption, which involves the loss of dentin, cementum, and/or bone due to physiological or pathological processes, can significantly impact treatment decisions [9, 10]. Several treatment options are available for replacing missing teeth in the affected region. Dental implants are generally not recommended in growing patients due to the potential for interference with the development of the jaw. In adults, bonded bridges are commonly used as a solution. Alternatively, orthodontic space closure can be employed, which preserves the alveolar bone and soft tissues, offering a more conservative approach [11]. Compared to dental implants and bonded bridges, orthodontic treatment is a more conservative approach that effectively addresses the patient’s primary concern in this report.

Orthodontic space closure is a viable alternative treatment when maxillary central incisors are missing, provided it is deemed appropriate for the case [12]. Although replacing central incisors with maxillary lateral incisors is rare, it is a viable option described in the literature, with few reports documenting its success [12, 13]. In such cases, canines may be used to substitute for lateral incisors, and the central incisors can be repaired or replaced with dental implants. However, the use of orthodontic space closure following the extraction of maxillary central incisors, combined with gingival surgical procedures to enhance both aesthetics and function, has not been widely reported. While space closure is a valid alternative for missing central incisors, this approach presents more challenges compared to space maintenance for future restorative work, as it often requires bodily movement of posterior teeth to close the spaces. Additionally, clinicians must consider the relationships between the teeth, gingival appearance and lip dynamics [14, 15, 16].

This case report describes an effective treatment option for a patient who underwent extraction of the maxillary central incisors, highlighting a feasible approach for space closure and the restoration of the maxillary gingival line. The treatment strategy involved an interdisciplinary approach, incorporating both orthodontic and periodontal procedures.

2. Clinical report

A 12-year-old girl presented with a crown fracture of the maxillary central incisors, accompanied by crown surface discoloration and slight protrusion of the dentition upon smiling. The patient reported a lack of confidence due to poor smile aesthetics and was reluctant to smile. She also expressed a desire for concurrent treatment to address her lip protrusion. The trauma occurred five years earlier, after which appropriate endodontic treatment was performed on the maxillary right central incisor. However, the patient exhibited signs of poor oral hygiene, with bacterial plaque accumulation leading to red, swollen gums, though no gingival hyperplasia was observed. The maxillary central incisors demonstrated grade 1 mobility, without the presence of a periodontal pocket. No significant bone loss was detected radiographically.

The patient had a Class I subdivision malocclusion on a Class II skeletal base (Fig. 1). The maxillary dental midline deviated 2.0 mm to the right, with an anterior overjet of 4.5 mm and an overbite of 2.0 mm. There was no crowding observed in either the maxillary or mandibular arches, and model analysis revealed that the anterior Bolton ratio was below the normal range (Fig. 2).

Fig. 1.Pretreatment facial and intraoral photographs.

Fig. 2.Pretreatment dental casts.

A panoramic radiograph revealed bilateral root resorption of the maxillary central incisors. Her four third molars were present, with the mandibular left third molar inclined forward. Cephalometric analysis revealed an acceptable vertical and anteroposterior skeletal relationship, with labial inclination of both the maxillary and mandibular incisors. The Upper Incisor to Sella-Nasion plane angle (U1-SN) was 120.4°, and the Lower Incisor to Mandibular Plane angle (L1-MP) was 99.3°. The patient had a convex soft tissue profile and an acute-angled nasolabial angle, along with noticeable lip protrusion (Table 1). There was no pain in the temporomandibular joints, and mouth opening was not limited. Based on these, she was diagnosed with skeletal Class II bialveolar protrusion with resorption of the maxillary central incisors (Fig. 3).

Fig. 3.Pretreatment radiographic records. (A) Initial panoramic radiograph; (B) Periapical radiograph; (C) Initial lateral cephalometric radiograph.

The patient expressed concerns about the unesthetic appearance of her maxillary central incisors and the convex profile of her face. The upper central incisor showed signs of root resorption, suggesting a poor long-term prognosis. Two treatment options were presented to address her concerns, differing in the approach to replacing the unhealthy central incisors. The first option involved mesially moving the maxillary lateral incisors to replace the central incisors, which required the extraction of the mandibular first premolars. This plan directly addresses the anterior arch protrusion by removing the maxillary incisors, which immediately reduces facial protrusion. It is well established that anterior teeth support facial contours, and the removal of the maxillary central incisors helps to alleviate facial protrusion. Additionally, controlling the torque of the lateral incisors and canines would improve the soft tissue profile.

The second option proposed a prosthetic replacement of the maxillary central incisors after the patient reached full skeletal maturity. In this treatment approach, the extraction of four first premolars were required to create the necessary space for reducing the anterior teeth protrusion and would be suitable for patients with forward dental arch thrusting. The injured anterior teeth could undergo root canal treatment and restored with crowns. If the long-term outcome of crown work is unsatisfactory, a dental implant could be considered, though this option is more expensive and involves procedures not aligned with the patient’s treatment goals or the parents’ preferences.

For this challenging case, the primary objective was to replace the unhealthy maxillary central incisors by mesially inclining the two maxillary lateral incisors to enhance smile aesthetics and improve the soft tissue profile, all while avoiding the need for implants and ensuring stable functional occlusion.

After explaining the details to the patient and her parents, with their approval, a decision was made to proceed with the first treatment option, and the and orthodontic treatment was initiated.

The first step involved the extraction of the maxillary right central incisor and bilateral mandibular first premolars (Fig. 4), and the upper left incisor was temporarily left in place. Self-ligating brackets, preadjusted with edgewise appliances, were placed on both arches, but no bracket was attached to the maxillary left central incisor. Bands were placed on all the first molars. Initially, 0.014-inch round nickel-titanium (Ni-Ti) archwires were used for arch leveling, followed by 0.018-inch round Ni-Ti archwires. Once all the teeth were aligned, 0.019 × 0.025-inch rectangular nickel-titanium archwires were ligated to correct the torque in both arches. After achieving alignment, 0.017 × 0.025-inch rectangular stainless steel archwires with distal bends were placed to facilitate space closure and further torque control. Within less than a year, the spaces left by the maxillary tooth extractions were closed. However, the extraction space was too small to improve the patient’s aesthetics. At this point, the maxillary left central incisor was extracted in the oral surgery department, and both the maxillary right and left lateral incisors were moved mesially (Figs. 5,6).

Fig. 4.Facial and intraoral progress photographs after extraction of the upper right central incisor.

Fig. 5.Facial and intraoral progress photographs after extraction of the upper left central incisor.

Fig. 6.Facial and intraoral photographs 19 months after treatment.

The delayed extraction of the upper left central incisor helped to temporarily preserve the width and height of the alveolar bone, which is important for the aesthetics of the anterior tooth area. During this phase, the maxillary right lateral incisor was moved into the position of the right central incisor, and the maxillary right canine was moved into the position of the lateral incisor. Keeping the maxillary left central incisor in place allowed the patient to retain confidence, as it prevented the simultaneous loss of both maxillary incisors [17, 18].

Chain elastics were used to close the space left by the central incisor extraction, with the power chain being changed every 2 months. Mandibular 0.019 × 0.025-inch rectangular nickel-titanium archwires were ligated to further correct the torque once the maxillary extraction space was closed. After 31 months of treatment, the fixed appliances were removed, and the dentition was maintained using a vacuum-formed retainer (Figs. 7,8).

Fig. 7.Posttreatment facial and intraoral photographs.

Fig. 8.Posttreatment dental casts.

Gingival hyperplasia was evident in the anterior tooth region, and an interdisciplinary treatment was deemed important and conducted. Periodontal treatment of gingival hyperplasia of the upper incisors was performed after orthodontic treatment (Fig. 9). The patient had gingival hyperplasia in the anterior dental area, and the gingival margins were not parallel. Before the spaces were fully closed, careful attention was given to the gingival aesthetics.

Fig. 9.Intraoral progress photographs of the gingivoplasty process. (A) Hyperplastic tissue before surgery; (B,C) Excision of hyperplastic tissue after gingival flap surgery, using a sulcular incision with flap repositioning; (D) Twenty days post-surgery.

A 1 mm gap was intentionally left between the upper incisors (Fig. 7) to facilitate the periodontal surgery. After the procedure, a Harley retainer was used to close the gap, which also helped compress the gums between the lateral incisors, improving the appearance of the gingival papilla. This method significantly reduced the formation of black triangles between the teeth (Fig. 10).

Fig. 10.Facial and intraoral photographs showing the results of gingival hyperplasia treatment at the 6-month follow-up.

The hyperplastic tissue was successfully removed without compromising the biological width, and after six month, the patient’s gingival morphology recovered well (Fig. 10).

Gingival surgery is a critical step in achieving optimal aesthetics. Typically, orthodontic treatment precedes periodontal therapy because extrusion or intrusion of the teeth can affect the balance of the gingiva [19, 20]. The shape and size of both the lateral incisor and central incisor were carefully coordinated, with no additional space required for the restoration of the lateral incisor.

The overall treatment outcome was excellent. The patient’s profile and smile arc showed significant improvements, with ideal Class I molar and bilateral “canine” (first premolar replacement) relationships. The anterior overjet and overbite were also optimized. The maxillary anterior teeth were successfully replaced, giving the patient a brighter smile. In addition, the sagittal relationship was improved, and the patient demonstrated good lip competence and projection. As a result, the patient regained confidence in her appearance.

The ANB angle decreased from 4.9° to 3.4° after treatment, primarily due to the significant distal movement of the A-point resulting from the palatal repositioning of the incisors. As a result, the maxillary incisors were extremely receded (U1-SN, 100.2°), while the mandibular incisors were positioned upright (L1-MP, 89.9°) (Figs. 11,12, Table 1). The reshaping of the gingiva around the anterior teeth contributed to a more balanced and aesthetically pleasing smile arc. Cone-beam computed tomography (CBCT) confirmed that the roots of all anterior teeth were well aligned and appropriately angled after treatment, with no evidence of root resorption (Fig. 11).

Fig. 11.Post-treatment radiographic records and pre-/post-treatment cephalometric superimposition. (A) Final panoramic radiograph; (B) Final lateral cephalometric radiograph; (C) Superimposition of initial and final cephalometric tracings (initial in black, final in green).

Fig. 12.Changes in the smile line before and after treatment. After treatment, the maxillary gingival line coincided with the lower edge of the upper lip when the patient smiled.

There were no issues with the temporomandibular joints (TMJ) at the start of treatment, and no signs of TMJ discomfort or dysfunction arose during the treatment or retention phases. Apart from the orthodontic adjustments, the only other procedure performed was gingivoplasty, which was crucial for optimizing the gingival contour. Importantly, no probing depths greater than 4 mm were observed. As a result, the treatment successfully improved the patient’s aesthetic smile and provided a functionally stable occlusion, which remained stable at the 2-year follow-up assessment (Fig. 13). The retention protocol, which played an equally important role in maintaining treatment results, involved the use of a vacuum-formed retainer to stabilize the dentition.

Fig. 13.Facial and intraoral photographs at the 2-year follow-up.

Assessing the impact of both the incisors and lateral incisors on the aesthetic appearance and occlusion in orthodontically treated patients is a complex task, as it involves multiple factors. In addition to this, the positioning and functional integration of the canines also present significant challenges. The torque exerted by the tongue on the roots of the canines can limit the extent of their protrusion, a phenomenon that is similarly observed in the lateral incisors. Furthermore, the reconstruction of gingival morphology plays a crucial role in achieving the overall success of the treatment, as it directly influences both the aesthetic and functional outcomes in the long term.

3. Discussion

Traumatic dental injuries are common in children [21, 22], particularly in those aged 6 to 12 years. Given the high incidence of dental trauma in this age group, active prevention and timely treatment are essential not only for maintaining oral function but also for supporting the socio-psychological well-being of children and adolescents [1, 23, 24, 25]. Severe dental trauma often leads to compromised tooth vitality and root damage, including root resorption [26, 27]. Although the aetiology and pathogenesis of root resorption are not fully understood, trauma is considered one of the most significant contributing factors. External inflammatory resorption typically occurs on the lateral root surface or at the apex of the root [28]. Therefore, radiographic examination, particularly Cone-Beam Computed Tomography (CBCT), is critical for diagnosing root resorption accurately. While root canal treatment is commonly effective, it may not always prevent the progression of inflammatory resorption [29, 30, 31, 32]. In cases where the prognosis of a traumatized tooth is poor, multidisciplinary treatment should be considered to improve the overall outcome.

One potential treatment option for patients with incisor trauma and root resorption is the substitution of lateral incisors for maxillary central incisors. In this case, lateral incisors proved to be a favorable substitute due to their similar mesiodistal width compared to the central incisors. However, mismatches in tooth shape, color and size can compromise the success of this treatment. Fortunately, in this study, the patient’s lateral incisors and canines were well-matched with the central incisor and lateral incisor, respectively, in terms of shape, size and color. Although the crown width of the maxillary central incisor is slightly larger than that of the lateral incisor (8 mm vs. 7.8 mm), the differences in vertical height and gingival architecture necessitated orthodontic treatment and gingivectomy to control the crown length [33, 34]. Additionally, the position, size and relationship of the canine to the soft tissue are considered essential factors. In some cases, reshaping and recontouring of the canine may be required to achieve the ideal shape and size for the lateral incisor [35]. In our case, the shape and size of the canine were similar to those of the lateral incisor, and any small differences did not affect the aesthetics.

Compared to implant prostheses, orthodontic-periodontal treatment is often preferable because it focuses on replacing the central incisors while addressing the psychological impact of trauma. Implant success and survival rates are not guaranteed, and patients may find the results less satisfactory. Furthermore, the process of implant placement is time-consuming and painful, often leading to anxiety and fear among patients [36]. Therefore, orthodontic-periodontal treatment, which offers a less invasive and more conservative approach, presents a valuable alternative for managing traumatic dental injuries while minimizing both physical and emotional distress.

Patients are often more inclined to undergo orthodontic-periodontal treatment, as this protocol effectively closes the gaps remaining after the extraction of the upper central incisors through mesial movement of the maxillary dentition. However, long-distance movement of teeth can increase the risk of complications such as tooth vitality loss, discoloration, alveolar bone loss, gingival recession and gingival hyperplasia, all of which can lead to aesthetic concerns or root resorption [37, 38, 39, 40, 41]. To minimize these risks, light and continuous orthodontic forces are recommended. In our present case, with the loss of two maxillary teeth, a two-tooth-wide gap was needed to be closed by bilateral mesial movement of the adjacent teeth, and our applied method of space closure has been shown to yield satisfactory long-term aesthetic and functional results [42]. The treatment plan for this patient involved first extracting the maxillary right central incisor, followed by the extraction of the maxillary left central incisor. This approach effectively preserves the alveolar bone of the maxillary incisors. As the space left by the extraction gradually narrowed, the maxillary left central incisor could then be extracted. This progressive reduction in mesiodistal dimension helped maintain anchorage, facilitating the correction of the Class I relationship. On the other hand, extracting both teeth simultaneously would result in a large edentulous space, potentially compromising the thickness of the alveolar bone in that region [17, 43]. It is important to move the teeth promptly after extraction, and the optimal timing for tooth movement should be considered during the clinical healing stage of the extraction site, as bone remodeling can be maximized during this phase. Additionally, the rate of tooth movement tends to be faster when a tooth is moved into a recent extraction site compared to a healed extraction site [44, 45].

The gingival architecture of the incisors should be bilaterally symmetrical and aesthetically pleasing, and achieving this goal often requires a combination of both orthodontic procedures and periodontal surgical methods. Over time, the focus of periodontics has shifted from purely health-related services to enhancing smile aesthetics [46, 47, 48]. In our current case, a combined orthodontic and periodontal approach was chosen to replace the central incisors with the lateral incisors, as modifying the gingiva is essential to achieve the desired aesthetic results. Periodontal plastic procedures, such as gingivectomy, can reshape the silhouette of the teeth and improve their relative proportions. Specifically, gingivectomy of the lateral incisor can increase its clinical crown height, further contributing to the aesthetic outcome.

One aspect that has not been extensively studied is whether the extraction of the maxillary central incisors leads to Bolton index dysregulation. In our case, there was no significant difference in the Bolton index between the extraction of the central incisor and the extraction of two mandibular first premolars or four first premolars. The overall Bolton index was 90.69%, and the Bolton index for the anterior teeth was 78%. This finding suggests that the patient’s tooth size was well coordinated. Bolton’s analysis is applicable to all patients, regardless of the type of malocclusion, and the Bolton ratio after correction represents an essential parameter for evaluating posterior arch stability before treatment [49, 50]. After treatment, the overall percentage was 90.7% and the anterior ratio was 80.5%, which indicates the importance of properly coordinating the maxillary and mandibular teeth for optimal results. Although successful treatment may not always result in an aesthetic smile, a combined orthodontic-periodontal approach can help achieve a more beautiful smile. We believe that establishing a harmonious lip-to-teeth relationship is a primary goal of treatment. However, there are limited objective criteria for assessing the attributes of a smile, which underscores the importance of aesthetics in orthodontic planning. In cases where poor vertical control leads to maxillary incisor intrusion to open the bite, unwanted flattening of the smile arc may occur [51]. Therefore, careful consideration of vertical control is essential to ensure the best aesthetic outcome.

The limitations of this options lie in its stringent requirement for tooth size similarity among patients. If there is a significant discrepancy in size between the central and lateral incisors, crown restoration may be necessary to achieve optimal aesthetic outcomes.

4. Conclusion

In conclusion, the effective management of orthodontic cases requires a multidisciplinary approach that integrates the expertise of both orthodontists and periodontists. This case report demonstrates the successful application of an interdisciplinary approach to orthodontic treatment. The careful selection of appropriate treatment methods and professional skills were crucial for achieving optimal results. After treatment, the patient presented with an aesthetically pleasing smile, characterized by a symmetric gingival contour that harmonized with the upper lip and a normal tooth length, highlighting the effectiveness of the multidisciplinary approach.

Availability of data and materials

The case report data supporting this study’s findings are available from the corresponding author upon request.

Author contributions

JJ and BCT—developed the treatment plan and performed the treatment. QZ and QRY—wrote the manuscript. JZ—compiled the medical imaging records for the case report. TCW and JDC—analyzed the data. HL—provided guidance on manuscript preparation. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript.

Ethics approval and consent to participate

Since this is a case report and does not involve research or clinical trials, the Medical Ethics Committee of the School of Medicine and Stomatology at Nanjing University has exempted it from the requirement of ethical approval. Written informed consent has been obtained from the patient’s parents.

Acknowledgment

We thank the patient and her parents.

Funding

This research was funded by Key Project Supported by Medical Science and Technology Development Foundation, Nanjing Department of Health, grant number ZKX24058; The Key Project of The Health Commission of Jiangsu Province, grant number: ZD2022025; Cultivation Program for Reserve Talents for Academic Leaders of Nanjing Stomatological School, Medical School of Nanjing University, grant number: 0223A209, 0223A101; High-Level Hospital Construction Project of Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Institute of Stomatology, Nanjing University, grant number: 0224C013, 0224C005, 0224C045.

Conflict of interest

The authors declare no conflict of interest.