Mockutė G, Klimaitė G, Smailienė D The morphology of impacted maxillary central incisors: a systematic review. Medicina. 2022; 58 https://doi.org/10.3390/medicina58040462
Grover PS, Lorton L The incidence of unerupted permanent teeth and related clinical cases. Oral Surg Oral Med Oral Pathol. 1985; 59:420-425 https://doi.org/10.1016/0030-4220(85)90070-2
de Amorim CS, Americano GCA, Moliterno LFM, de Marsillac M de WS, Andrade MRTC, Campos V Frequency of crown and root dilaceration of permanent incisors after dental trauma to their predecessor teeth. Dent Traumatol. 2018; 34:401-405 https://doi.org/10.1111/edt.12433
Shaw WC, O'Brien KD, Richmond S, Brook P Quality control in orthodontics: risk/benefit considerations. Br Dent J. 1991; 170:33-37 https://doi.org/10.1038/sj.bdj.4807399
Chaushu S, Zilberman Y, Becker A Maxillary incisor impaction and its relationship to canine displacement. Am J Orthod Dentofacial Orthop. 2003; 124:144-150 https://doi.org/10.1016/S0889-5406(03)00344-5
Chaushu S, Dykstein N, Ben-Bassat Y, Becker A Periodontal status of impacted maxillary incisors uncovered by 2 different surgical techniques. J Oral Maxillofac Surg. 2009; 67:120-124 https://doi.org/10.1016/j.joms.2008.08.012
Caeiro-Villasenín L, Serna-Muñoz C, Pérez-Silva A, Vicente-Hernández A, Poza-Pascual A, Ortiz-Ruiz AJ Developmental dental defects in permanent teeth resulting from trauma in primary dentition: a systematic review. Int J Environ Res Public Health. 2022; 19 https://doi.org/10.3390/ijerph19020754
Diab M, elBadrawy HE Intrusion injuries of primary incisors. Part III: effects on the permanent successors. Quintessence Int. 2000; 31:377-384
Žarovienė A, Grinkevičienė D, Trakinienė G, Smailienė D Post-treatment status of impacted maxillary central incisors following surgical-orthodontic treatment: a systematic review. Medicina (Kaunas). 2021; 57 https://doi.org/10.3390/medicina57080783
Woloshyn H, Artun J, Kennedy DB, Joondeph DR Pulpal and periodontal reactions to orthodontic alignment of palatally impacted canines. Angle Orthod. 1994; 64:257-264
Makwana M, Murray A Coronal resorption in unerupted anterior permanent teeth: cases with different aetiologies? A review. Orthod Update. 2022; 15:97-104 https://doi.org/10.12968/ortu.2022.15.2.97
Despite their relatively low incidence, unerupted maxillary incisors have a sizeable impact on a patient's function, phonetics and aesthetics. Management of these teeth commonly involves surgical exposure and orthodontic traction. This report describes a previously unreported intra-operative finding. During surgical exposure of an unerupted maxillary incisor, the pulpal tissue was found to be continuous with the oral mucosa. Subsequent separation of the tissues resulted in pulpal necrosis, requiring endodontic management. Awareness of unique complications is required. To ensure valid consent, all risks and alternative treatment options for these must be clearly communicated.
CPD/Clinical Relevance: Despite meticulous planning, not all intra-operative complications can be anticipated, hence good patient communication is important.
Article
Eruption failure of maxillary incisor teeth typically presents in the mixed dentition, over the age of 7–9 years. The maxillary central incisor is the third most commonly impacted tooth, after the third molar and maxillary canine. The reported incidence level varies from 0.03% to 2.1%.1,2 Failure of eruption can broadly be attributed to space loss, obstruction or trauma.1,3
The maxillary midline is a common site for supernumerary teeth or odontomes, which provide a physical obstruction to eruption. Additionally, trauma to deciduous teeth can result in malformation or dilaceration to the permanent successor. A change in the position or morphology of a developing tooth can result in eruption failure.4
Notably, an absent or unerupted maxillary incisor can affect patient function, phonetics and aesthetics.5 Consequently, early diagnosis, thorough investigation and appropriate treatment planning are essential.
Often, a multidisciplinary approach is required. This involves a timely referral from general dental practitioners and specialist management from oral surgeons and orthodontists.6 Most commonly, surgical management of the unerupted tooth involves closed exposure and gold chain traction. This method has been cited to be successful in more than 90% of cases.7
Furthermore, the literature indicates that closed exposure provides more favourable gingival, periodontal and pulpal outcomes compared to the open exposure technique.8
Common risks of surgical exposure include pain, bleeding, bruising, swelling, infection, damage to adjacent structures, non-eruption, loss of soft tissue/attached gingiva and the need for re-exposure.9
However, this case report discusses a novel intra-operative risk, that of pulpal tissue being fused to the oral mucosa.
Case report
A fit and well 9-year-old girl presented to St Luke's Hospital Oral Surgery Department, for assessment and management of the ‘gap at the front of her mouth’.
The patient provided a history of trauma, having experienced intrusion injuries to the upper primary incisors aged 4 years.
On examination, the patient had an unerupted maxillary incisor (UL1) which was visible and easily palpable in the buccal sulcus (Figure 1).
Plain film and cone beam computed tomography (CBCT) radiographic examination revealed the ectopic position of the UL1 (Figure 2). It lay transversely across the arch, with the crown perforating the labial cortical plate. Its root was dilacerated, with a mild superior curve in the apical third. The radiolucency noted at the incisal tip was attributed to coronal resorption.
The patient was listed for closed exposure of the UL1 with gold chain attachment under local anaesthetic.
An apical repositioned flap was raised to access the unerupted tooth. Once visualized, it was noted that the crown of the UL1 contained a mass of soft tissue, thought to be pulpal tissue. This tissue was also fused to the labial mucosa (Figure 3a). Following tissue separation, the flap was repositioned and secured with resorbable sutures (Figure 3b). A gold chain was not secured on the day of surgery.
Figure 3.
(a) Intra-operative photograph demonstrating soft tissue defect continuous with labial mucosa. (b) Intra-operative photograph demonstrating separation of tissues and flap reposition.
The tooth became symptomatic, prompting endodontic treatment by the patient's general dentist.
Currently, the tooth is being successfully aligned using an upper removable appliance. An elastic band connects an attachment on the UL1 to a hook at the back of the appliance (Figure 4).
Figure 4.
(a,b) Intra-oral photographs to demonstrate alignment set-up for the UL1.
This set-up provides controlled vertical anchorage, facilitating the extrusion and palatal movement of the tooth while minimizing intrusive forces on the upper incisors. This is crucial in cases like this where there is an existing anterior open bite, to prevent it from worsening. The next step in treatment will involve transitioning to upper and lower fixed appliances.
Discussion
This case study explores the impact of trauma to the primary dentition on the developing tooth germ, with a focus on intrusion injuries. Owing to the axial force involved, intrusion injuries are associated with more severe defects to the permanent successor.10
Pathological changes to the developing tooth may include enamel hypoplasia, crown or root dilaceration, arrested root formation, sequestration of the permanent tooth germ and eruption disturbances.11
In this case, the tooth was highly impacted, presenting with root dilaceration and a radiolucency to the crown. Impacted teeth with dilacerated roots are shown to have poorer treatment outcomes.12 Such cases are associated with multiple surgical exposures, prolonged extrusion times, ankylosis and treatment failure requiring tooth extraction. Additionally, to achieve orthodontic alignment, highly impacted teeth require more extreme movements and forces. Consequently, these teeth are more susceptible to adverse pulpal outcomes.13
The radiographic changes observed in the crown may be attributed to pre-eruptive intra-coronal radiolucency (PEIR).14 PEIR manifests as a radiolucent lesion in the dentine of an unerupted tooth, located below the enamel–dentine junction.15 These lesions can vary in depth and may extend into the pulp. Although the aetiology of PEIR is not fully understood, existing literature suggests that these lesions are resorptive in nature.16
Several case reports have described the clinical presentation of PEIR similar to the case outlined here.17 These reports detail defects containing a mass of erythematous soft tissue, resembling pulp. It is thought that during resorption of enamel and dentine, hard tissue is replaced by vascular connective tissue.18,19
This particular case deviates from the norm because there was apparent fusion of the central soft tissue with the labial mucosa. It is plausible that this case is complicated by the significantly altered orientation of the tooth.
Identifying anatomical variants, such as those described in this case, is crucial before surgical intervention. Thorough investigation of unerupted teeth, using CBCT analysis, provides precise localization, orientation and identification of anatomical anomalies. This allows for surgical plans to be tailored to the individual.
However, despite meticulous planning, not all intra-operative complications can be anticipated, especially when facing novel issues such as the tissue fusion observed in this case. We have not yet found any literature describing this specific intra-operative challenge. Therefore, it is important that this is brought to the attention of the profession.
Considering these issues, it is essential that the poorer prognosis of this tooth is communicated to the patient. Although the tooth is being aligned, its long-term prognosis remains guarded, and it is possible that extraction and prosthetic replacement may be necessary in the future.
Conclusion
This case highlights the challenges involved in the management of an impacted maxillary incisor, particularly when complicated by trauma-induced root dilaceration and PEIR. The unusual finding of soft tissue fusion between pulpal tissue and the labial mucosa, previously unreported, highlights the need for comprehensive pre-operative investigation.
While CBCT analysis provides critical insights for surgical intervention, not all intra-operative complications can be foreseen, especially when dealing with novel presentations such as tissue fusion. This case emphasizes the need for heightened awareness of such complications within the dental profession, because they have a significant impact on treatment outcomes.
Moreover, clear communication of prognosis with patients is essential for informed care. Given the inherent complexity of these cases, they are most effectively managed through a multidisciplinary approach.
