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| CASE REPORT |
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| Year : 2016 | Volume
: 7
| Issue : 4 | Page : 152-156 |
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Resorption of Lateral Incisors during Canine Eruption: Two Clinical Cases with Focus on Root Lengths and Heredity
Mostafa Zargham1, Inger Kjær2
1 Department of Dental, Oral and Maxilliofacial Surgery, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
2 Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| Date of Web Publication | 21-Dec-2016 |
Correspondence Address:
Inger Kjær
Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, 20 Nørre Allé, DK-2200 Copenhagen N
Denmark
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/2155-8213.195976
Introduction: It is well-known that pressure from orthodontic appliance can provoke root resorption in dentitions with short roots. The purpose of this case report is to demonstrate two clinical cases with focus on root length in dentitions exposed due to pressure from erupting teeth. This is a pilot study aimed to improve diagnostics for avoiding the resorption of lateral maxillary incisors by pressure from erupting canines. Case Report: The first reported case is of a girl who was 11 years and 7 months old when radiographs showed severe resorption of the lateral incisors, along with malformed central incisors and short roots. The intraoral photos demonstrated light crowding in the maxilla. The orthopantomogram of the girl’s mother demonstrated several short roots. The second reported case is of a girl who was 9 years and 5 months old when radiographs demonstrated nearly complete resorption on her lateral incisor roots, extremely short roots in the central incisors, and short roots. The intraoral photos demonstrated light crowding in the maxilla. The orthopantomogram of the girl’s mother demonstrated extremely short roots in general. Conclusion: This pilot study indicates that short root length in general and abnormal incisor morphology are phenotypic traits that were characteristic for both girls who presented with severe lateral incisor resorption due to erupting canines. Furthermore, short roots were also demonstrated in the mothers. Accordingly, short root length in general could be a phenotypic trait, which should be diagnosed early for preventing severe resorption of lateral incisors during canine eruption.
Keywords: Canine, genetics, incisor, radiography, resorption, tooth morphology
How to cite this article:
Zargham M, Kjær I. Resorption of Lateral Incisors during Canine Eruption: Two Clinical Cases with Focus on Root Lengths and Heredity. Dent Hypotheses 2016;7:152-6 |
| Introduction | |  |
Permanent teeth do not undergo root resorption under normal conditions. Root resorption occurs under well-known pathological conditions and occurs unexpectedly, the so-called idiopatic resorption.
Resorption with known etiology can occur after trauma, due to pressure in the periodontal ligament, for example, in connection with tooth eruption, orthodontic tooth movement, or pressure from tumors. It can also occur in certain diseases such as ectodermal dysplasia.
Resorption due to pressure from erupting teeth is still not understood. The question is when and why does this resorption occur? Is it because of weakness in the protection of the root of the already erupted tooth or is it caused by the crown follicle of the erupting tooth? This resorption process could also be related to lack of space in the dentition. There is a need for more knowledge in order to prevent severe permanent root resorption due to pressure from erupting teeth.
Unknown etiology of root resorption is difficult to understand. The reason for this is that a short root could have been formed from the beginning, and in this case it is not a question of resorption. The research in this field is ongoing. The studies until now have revealed individual differences in susceptibility for root resorption. Early studies on root resorption have focused on the occurrence of resorption in dentitions with agenesis and deviant morphological traits.[1] Mainly, two categories of morphological traits seem to be predisposed for root resorption during orthodontic treatment. One category was characterized by phenotypic traits such as deviant crown shapes, invaginations, and taurodontic molar roots or slim roots.[1] The other category was characterized by dentitions with short, plumb roots often combined with open bite.[1] It has been difficult to understand whether a common factor could predispose for root resorption in morphologically different dentitions. It has, therefore, been concluded that different etiologies are the most likely explanation for root resorption.
In recent studies, different tissue types in cell layers covering the root, forming the so-called periroot sheet, has been suggested to protect the root against root resorption [Figure 1]. This peri-root sheet enabled an understanding of how deviations in different tissue types could cause inflammation which could provoke root resorption.[2],[3],[4] The possible influence from the periroot sheet on root length has still not been investigated. | Figure 1 The schematic overview of the tissue types in the root-close periodontal membrane. The tissue types within the blue circle marked is root dentine (light gray), cementum (dark gray), innervation layer close to the cememtum (yellow dots), and covering the innervation layer is a fiber layer (green crosses). Outermost in the root-close membrane are oblong ectodermal tissue components, Malassez’s epithelium (dark red). Light red contours indicate surrounding vessels. The parallel lines to the left indicate the loose periodontal tissue layer
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Resorption can occur in different areas of the root, often apically, however, cervical resorption and mid-root resorption also occur. It has been demonstrated that the etiology behind cervical resorption might be disturbances in the regional cervical innervation.
In addition, the inherited occurrence of resorption could possibly be explained from the characteristics of tissue types in the periroot sheets, within families. The purpose of this case report is to demonstrate cases presenting young female patients with severe resorption of lateral incisors and focus on a possible relationship between the pressure provoked by the canines during eruption and on the root length in these dentitions. For a possible understanding of inheritance of susceptibility of root resorption, the relationship between root length in each patient and the root length in their mother’s dentition is highlighted. The overall aim is to improve early prevention of severe resorption of lateral incisors during canine eruption.
| Case Reports | | |
Case 1
Description of the patient and the patient’s mother
Patient: Girl, healthy, aged 11 years and 7 months. Before orthodontic treatment, intraoral photographs [Figure 2], orthopantomogram, profile radiographs, and dental radiographs [Figure 3] were taken. | Figure 2 Case 1: Intraoral photographs of the dentition of a female patient aged 11 years and 7 months. The permanent canines have not erupted. The space for the permanent canines are slightly reduced
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 | Figure 3 Case 1: Orthopantomogram, profile radiograph and dental films from a female patient aged 11 years and 7 months. Note severe resorption of the permanent lateral incisors and malformed and short central incisors. On the profile, the maxilla appears retrognatic, and on the orthopantomogram, the canines have ectopic positions. Several roots are short
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Patient's mother: Healthy with no prior history of orthodontic treatment. The mother requested that radiographs were taken of her [Figure 4] for determining whether heredity could be determined. | Figure 4 Mother of case 1: The orthopantomogram and dental film demonstrate short central incisors and single short premolar roots
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Results concerning patient and the patient’s mother
Patient: Space analysis showed light crowding in the maxilla and mandible. Retrognatia of the maxilla.
Dental analysis: Demonstrated ectopia of both permanent canines and severe resorption of the lateral incisors, along with invagination and malformation in permanent incisors. Short roots in the dentition in general.
Patient's mother: Radiographs demonstrated several short roots.
Case 2
Description of the patient and the patient’s mother
Patient: Girl, healthy, aged 9 years and 5 months. Dental radiographs were taken before orthodontic treatment. Orthopantomogram and dental film are demonstrated in Figure 5. | Figure 5 Case 2: Orthopantomogram and dental films from a female patient aged 9 years and 5 months. Both lateral incisors have been completely resorbed of the canines, which have a normal position (not ectopic). The roots appear extremely short in general. The dental film demonstrates the severe resorption of the roots of the lateral incisor
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Patient's mother: Healthy with no previous history of orthodontic treatment. The mother requested that radiographs were taken of her [Figure 6] for determining whether heredity could be determined. | Figure 6 Mother of case 2: The orthopantomogram of the mother demonstrates extremely short roots. The mother had never received orthodontic treatments
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Results concerning patient and the patient’s mother
Patient: Space analysis showed light crowding in the maxilla and mandible.
Dental analysis: Ectopia of permanent canines was not observed. Complete resorption of the lateral incisor roots was observed. Clinically, the crowns appeared loose (second degree) and the central incisors were extremely short. The dentition in general appeared with very short roots.
Patient's mother: The mother’s radiograph demonstrated extremely short roots.
| Discussion | | |
The two demonstrated cases showed severe resorption of the lateral incisor roots during canine eruption. In both the cases, the roots appear short in the dentition. Radiographs of the children’s mothers were taken after the mothers’ requests in order to understand the causes of resorption in the children. The study showed that the roots in the mother’s radiographs also appeared short.
The first question is whether there is an indication of recommending radiographs of the parents when resorption is observed in children before orthodontic treatment. This is still doubtful. A more thorough study including gender differences is still needed.
It is well-known from orthodontics that deviant resorption patterns are seen in siblings. Orthodontists often treat siblings and therefore have radiographic material. It is important that orthodontists are aware not only of the sibling relation but also of the parent/child relation. It should be examined whether gender differences occur in the hereditary pattern. It is well-known that resorption is more often occurring in girls than in boys. Resorption is a biological process that occurs without orthodontic treatment, however, it is often described as a sequelae of the treatment choice of the orthodontist, which is misleading. From this point of view, the question regarding gender and heredity should take a central role in the anamnesis before orthodontic treatment is initiated.
The actual case reports are pilot studies focusing on the phenotypic traits of the importance for preventing severe resorptions of lateral incisors during canine eruption. In both the case reports, light crowding was recorded. It is remarkable that the most severe resorption of incisor roots was seen in case 2 with less crowding and canines, which were not ectopic. In case 2, the root length was also significantly shorter than that in case 1. These observations in case 2 indicated that this patient had a very strong susceptibility for resorption of lateral incisors during canine eruption.It is known that dentitions with palatal located canines have more dental deviations than normally observed.[5] Meanwhile, root length has not been elucidated systematically in cases with palatinal canine ectopia.
It is important to prevent severe resorption of lateral incisors and to continue the search for phenotypic traits of importance for early diagnosis early treatment.
| Conclusion | | |
In two cases of young females, severe resorption of permanent lateral incisors due to pressure from canine eruption were reported. In both cases, the dentitions had malformed central incisors and general short roots. The mothers of the young patients also demonstrated very short roots. It is recommended that root length undergoes further investigation as a useable parameter in the evaluation of possible resorption from erupting canines.
This pilot study has been performed for the improvement of diagnosis for early treatment of erupting canines, with the aim of avoiding severe resorption of the lateral incisors.
Financial support and sponsorship
Nil.
Conflicts of interest
Inger Kjær has editorial involvement with Dent Hypotheses.
| References | | |
| 1. | Kjær I. Morphological characteristics of dentitions developing excessive root resorption during orthodontic treatment. Eur J Orthod 1995;17:25-34.  |
| 2. | Kjær I. External root resorption − different aetiologies explained from the composition of the human root-close periodontal membrane. Dent Hypotheses 2013;4:75-9. |
| 3. | Kjær I. Root resorption − focus on signs and symptoms of importance for avoiding root resorption during orthodontic treatment. Dent Hypotheses 2014;5:47-52. |
| 4. | Kjær I, Nolting D. The human periodontal membrane − focusing on the spatial interrelation between the epithelial layer of Malassez, fibers, and innervation. Acta Odontol Scand 2009;67:134-8. |
| 5. | Sørensen HB, Artmann L, Larsen HJ, Kjær I. Radiographic assessment of dental anomalies in patients with ectopic maxillary canines. Int J Paediatr Dent 2009;19:108-14. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
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