From Volume 8, Issue 1, January 2015 | Pages 19-22
This report discusses a case of rare idiopathic root resorption in a 13-year-old female and highlights how an upper standard occlusal radiograph proved to be pivotal in the diagnosis and demonstration of its incidence. Management of the case is described, with discussion of treatment alternatives.
Root resorption is the term used to describe the process of progressive loss of dentine and cementum.1 Root resorption can be broadly classified based on the site of the process as internal or external. The main causes of root resorption are summarized in Table 1.
| Local | Systemic |
|---|---|
| Orthodontic tooth movement - most common2 | Pathology - ameloblastoma, giant cell tumours, cysts3 |
| Trauma/occlusal trauma | Oxalate concentration in blood4 |
| Impaction | Endocrine imbalance - hyperparathyroidism, hypoparathyroidism |
| Pulpal/periodontal inflammation | Paget's disease2 |
| Pulpal necrosis | Hypophosphataemia |
| Iatrogenic - root planing, dento-alveolar surgery, tooth whitening4 | Syndromes - Goltz, Papillon-Lefevre Turner |
There are four further categories of root resorption:
Often the aetiology of root resorption may be multi-factorial.2 By definition, idiopathic root resorption arises where there is no identifiable cause and therefore absence of local or systemic factors.3,4 Idiopathic root resorption can be either localized or generalized. Two types of idiopathic root resorption have been observed; apical and cervical.5,6 Cervical idiopathic root resorption starts in the cervical area, progressing towards the pulp. In the apical idiopathic root resorption type, progression is coronal, resulting in slow shortening and blunting of the remaining root. Apical idiopathic root resorption is more common than the cervical type.7
Despite the lack of known causes, a proposed aetiological mechanism for idiopathic root resorption is thought to be due to microbiologically-induced osteoclast activity facilitated by prior osteoblast activation.8 Other research suggests that there may also be a genetic predisposition to the more aggressive patterns of this type of resorption.9 Harris et al also analysed possible aetiological factors which could be associated with idiopathic resorption in patients who had not undergone any previous orthodontic treatment.10 The authors suggested that a reduced number of teeth can potentially place increased load on the remaining teeth and accelerate the process of root resorption. Such teeth affected by idiopathic root resorption tend to have a poor long-term prognosis due to the progressive quality of the resorptive process. This therefore has implications for orthodontic intervention.
Radiographic assessment pre-orthodontic treatment is essential in all treatment planning. Witcher et al conducted a retrospective randomized controlled trial comparing orthopantomograms (OPGs) and upper anterior occlusal radiographs in the assessment of incisor teeth roots.11 They found that OPGs were not an ideal imaging modality for detecting abnormalities in root morphology or the presence of supernumerary teeth as these structures lie in the narrow focal trough. However, upper anterior occlusal radiographs reliably identified such issues.
This report illustrates a case of generalized idiopathic root resorption of the permanent dentition in a 13-year-old girl. The diagnosis and subsequent management of the case are also discussed.
A 13-year-old female was referred by her general dental practitioner for orthodontic assessment to the University of Manchester Dental Hospital. The patient's presenting complaint was of ‘crooked teeth.’ There was no relevant medical history, no previous orthodontic treatment and no history of dental trauma. In addition, there was no familial history of premature loss of teeth.
On extra-oral examination, the patient had a Class III incisor relationship on a mild Class III skeletal base, with increased vertical proportions. Intra-oral examination showed presence of the permanent dentition, including the second molars with an element of bimaxillary proclination. A reduced overbite and bilateral crossbite affecting the maxillary lateral incisors was also noted. The upper centreline was coincident with the upper mid facial axis but the lower centreline was displaced to the right. Both arches exhibited crowding with mild crowding in the lower and moderate crowding in the upper (Figure 1a). Caries was also present on the UR6 and LR6. The IOTN Dental Health Component was 4d with an Aesthetic Component of 7.
The records taken included clinical photographs (Figure 1), study models and baseline radiographs in the form of an OPG (Figure 2) and a lateral cephalogram.
Radiographs revealed the presence of all permanent teeth, including third molars. The OPG showed an incidental finding of root resorption affecting the mandibular incisors and premolars.
The status of the maxillary incisors was unclear from the OPG as this area is outside of the focal trough; as such it was felt to be prudent to take an upper anterior occlusal radiograph for further diagnostic information and clarification. This latter radiograph revealed an unexpectedly significant degree of root resorption affecting the maxillary incisor roots, which was particularly extensive on the lateral incisors (Figure 3). A potential diagnosis of idiopathic root resorption exacerbated by occlusal trauma was subsequently proposed.
A radiographic report of the available radiograph images was obtained by a consultant oral and maxillofacial radiologist with the following findings:
OPG: The following teeth display shortened roots: LR5, LR4, LR2, LR1, LL1, LL2, LL4, LL5.
Upper anterior occlusal: The UR1, UR2, UL1, UL2 display shortened roots. The UR2, UL2 display extensive root resorption on the distal aspects of their root surface.
Following the use of the intra-oral radiograph, the presence of resorption and its extent on the maxillary incisors was unequivocal.
As the long-term prognosis of a number of teeth and particularly the maxillary incisor teeth was poor, the patient was seen on a multidisciplinary hypodontia clinic to obtain a combined orthodontic/restorative/oral surgery opinion regarding the management of the patient's dentition. The patient was entirely asymptomatic despite the extensive root resorption. Consequently, it was proposed that the dentition should be monitored long term with a plan for interceptive treatment as and when signs or symptoms arose. The joint decision advised against provision of any orthodontic treatment to correct the anterior crossbites as this carried a real risk of accelerating the resorption, resulting in possible earlier tooth loss and expediting the requirement for prosthetic replacements.
Further discussion of options with the patient and her parents also included the use of a maxillary bonded retainer to facilitate physiological splinting of the upper incisor crowns to provide stability to the upper labial segment, whilst avoiding the risk of ankylosis. However, should the upper labial segment teeth display excessive mobility or symptoms before the patient's 16th birthday (the stage at which definitive prosthetic replacement with implant fixtures may be feasible), the short-term plan would be provision of a partial denture to restore the upper labial segment and provide space maintenance.
A 12-month review was arranged to re-assess the status of the root resorption of the maxillary incisors. Clinically, there were no changes evident compared to the initial presentation in terms of increased mobility, loss of vitality or further symptoms. A new upper anterior occlusal radiograph was taken and an additional radiographic report was obtained which concluded that there had been no change in the appearance of the maxillary incisors since initial imaging (Figure 4). An additional recommendation was also given to extend the time interval between radiological review.
A similar case report by Moazami and Karami found that, on average, 18 teeth were affected. In this case, 12 teeth were affected, which may be accounted for by the younger age of this patient, compared to the age of 27 years for the subject in the earlier study.12 The literature also shows conflicting data on whether there is a gender predilection, with some reports showing that idiopathic root resorption is more prevalent in females,13 whereas others have found that it is more common in males.6,12
A detailed clinical examination is an important tool to help formulate a clinical diagnosis. Despite a thorough clinical assessment, latent pathology may remain undetected. Special investigations, such as radiographs, help to support clinical impressions. As such, valid, sensitive and appropriate imaging should be used if they are to be truly diagnostic. This case report highlights the deficiencies of OPG radiographs in detecting and diagnosing maxillary incisor resorption. Moody and Muir also reported that an OPG is not an accurate method of screening the anterior maxilla pre-orthodontic treatment.8 In the absence of an upper anterior occlusal radiograph, there was a real risk in this instance of embarking on a course of active orthodontic treatment that may have had potentially catastrophic consequences.
This report also shows that there is a definite need to take appropriate radiographs to assess root morphology and length prior to active orthodontic treatment. The value of an upper anterior occlusal radiograph in diagnosing idiopathic root resorption was paramount to the informed consent and treatment planning processes in this case. It is recommended that, supplemental to published radiographic justification guidelines, an upper anterior occlusal radiograph may be indicated where image quality is poor from an OPG in the assessment of abnormal root morphology in the anterior regions.11 However, with advancements in alternative radiographic imaging, such as Cone-Beam CT, additional information regarding 3-dimensional extent of the resorption could be identified, further aiding treatment planning.14
Idiopathic root resorption is an unusual condition which, in the first instance, requires diagnosis and thereafter appropriate management. At present, upper standard occlusal radiographs are not routinely taken as part of pre-treatment orthodontic assessments and should not be used as a screening tool. However, the absence of this radiograph in this case may have led to lengthy fixed orthodontic treatment, which could have exacerbated pre-existing root resorption and resulted in the early loss of vulnerable teeth.
