Primary tooth radicular resorption as a consequence of self-corrected ectopic eruption: 2 unusual cases

Resorption of the distal root of primary second molars is a common consequence of ectopically erupting permanent first molars. Here, we report 2 unusual cases of primary molar root resorption caused by reversible (self-correcting) ectopic eruption of premolar and canine teeth. In both cases, severe pathological resorption of the mesial roots of primary molars was detected on routine dental radiographs, and the affected molars remained asymptomatic until exfoliation. The purpose of this paper was, using 2 case studies, to highlight the possibility of primary root resorption as a sequel of self-corrected ectopic eruption in locations not frequently diagnosed or reported.     

弹弓式磨牙远移器治疗上颌第一恒磨牙异位萌出

目的评价使用弹弓式磨牙远移器治疗第一恒磨牙异位萌出的临床效果。方法选择替牙期不可逆性第一恒磨牙异位萌出患者8例,男3例,女5例,年龄6.8~9.5岁,平均8.6岁。所有病例均存在不同程度的第二乳磨牙远中根吸收。采用弹弓式磨牙远移器标准型或简化型矫治器治疗,推第一恒磨牙向远中移动,使第一恒磨牙与第二乳磨牙远中面脱离接触并最终萌出到正常位置。结果所有病例第一恒磨牙牙冠均向远中移动并竖直,与第二乳磨牙脱离接触。治疗时间1.5~4.0个月,平均2.2个月。结论弹弓式磨牙远移器是治疗第一恒磨牙异位萌出的有效方法。     

External root resorption of the maxillary permanent incisors caused by ectopically erupting canines

In this study, we analyzed the root resorption of 10 maxillary permanent incisors (two central and eight lateral incisors) in seven cases associated with ectopic eruption of adjacent canines. Two incisors were extracted because of marked root resorption. Two erupted after traction, whereas, five erupted after surgical exposure or without any treatment, although one lateral incisor submerged due to ankylosis. This suggests that self-correction of the ectopic canine occurs in some cases.     

Root resorption associated with ectopically erupting maxillary permanent canines: a computed tomography study

The aims of this retrospective computed tomography (CT) study were to determine the occurrence of severe root resorption involving the pulpal canal of adjacent permanent teeth associated with ectopically erupting canines, and to verify the existence of related factors. The sample consisted of 255 consecutive patients (159 females and 96 males, mean age 18.4 and 16.8 years, respectively). Three hundred and thirty-four ectopic maxillary canines and adjacent teeth were analysed using CT images. Statistical significance was evaluated with chi-square and Fisher's exact tests. The results showed that severe root resorption of adjacent permanent teeth occurred in 17.7 per cent of ectopic canines and was equally common in females and males. Severe root resorption affected 12.6 per cent of the lateral incisors, 4.8 per cent of the first premolars, and 2.1 per cent of the central incisors. No relationship was found between the type or side of ectopic eruption, inclination of the longitudinal axis of the ectopic canine and the occurrence of severe root resorption. A significant relationship was found between a bucco-lingual position of the ectopic canine and root resorption (P < 0.05). Root resorption mainly occurred in the apical third (57.6 per cent) and apical and middle thirds (27.1 per cent). A significant relationship existed between the occurrence of root resorption and complete loss of space for the erupting canine (P < 0.05). No association was found between alignment of the upper permanent incisor and root resorption. A widened dental follicle occurred in 15 per cent of ectopic canines but did not cause root resorption of the adjacent permanent teeth. Since root resorption is asymptomatic, early detection by radiographic examination is essential for correct diagnosis and treatment.     

Orthodontic treatment for an adolescent with a history of acute lymphoblastic leukemia

This case report describes the treatment of a Class I malocclusion that involved ectopic position of the maxillary permanent left canine and the mandibular permanent right second molar. The patient was an adolescent who presented with a medical history that was remarkable for diagnosis and treatment of acute lymphoblastic leukemia (ALL). Dental history was remarkable for significant, generalized shortened roots that were more severe in the mandibular arch. The treatment included fixed appliance therapy in the maxillary arch only and surgical luxation of the mandibular second molar. Successful integration of the maxillary permanent left canine was accomplished without excessive flaring of the maxillary permanent incisors or disruption of the buccal segment occlusion. The risk of external root resorption on teeth with abnormal root morphology, as a result of fixed appliance therapy, should be weighed against the relative benefits that are expected from treatment.     

Resorption of maxillary lateral incisors caused by ectopic eruption of the canines : A clinical and radiographic analysis of predisposing factors

Factors predisposing to resorption of adjacent permanent lateral incisors caused by ectopic eruption of maxillary canines were evaluated. The subjects consisted of two groups: one with 40 lateral incisors with resorption caused by ectopic eruption and a control group of 118 ectopic eruption cases with no lateral incisor resorption. The mean age of the children in the two groups differed by only 0.7 of a year and ranged from 10.0 to 15.0 years, covering the normal eruption period of the maxillary canine. Resorption of lateral incisors was three times as common in girls as in boys. The resorption cases showed a more advanced dental development, a more medial canine position in the dental arch, and a slightly more mesial horizontal path of eruption (an average of 10 degrees) than that of the control cases. Factors such as the width of the dental follicle and proclination or distal tilting of the lateral incisor showed no correlation to the resorption. Potential resorption cases are always those in which the canine cusp in periapical and panoramic films is positioned medially to the midline of the lateral incisor. Such situations should be carefully investigated with polytomography if necessary. The risk of resorption also will increase with a more mesial horizontal path of eruption. From 10 years of age or younger, annual clinical examination by palpation of the canine eruption path is recommended. This clinical examination should be supplemented with a stepwise extended radiographic procedure in cases in which ectopic eruption of the maxillary canines is suspected.     

第一恒磨牙异位萌出倾斜角度与第二乳磨牙牙根吸收程度相关性研究

目的    通过曲面体层片测量分析第一恒磨牙异位萌出倾斜角度与第二乳磨牙牙根吸收程度的相关性。方法    选取2015—2020年于中山市人民医院儿童口腔科就诊的第一恒磨牙异位萌出患儿473例,共计患牙690颗,将其相邻第二乳磨牙牙根吸收程度分为Ⅰ ~ Ⅳ级。测量第一恒磨牙近中倾斜角度,并分析其与第二乳磨牙牙根吸收程度的相关性。结果    上颌第二乳磨牙牙根吸收Ⅱ ~ Ⅳ级的相邻第一恒磨牙倾斜角度依次为（102.2 ± 8.5）、（98.8 ± 8.8）、（92.7 ± 8.5）°,两者之间存在显著的负相关性（r = -0.4,P < 0.05）。下颌第二乳磨牙牙根吸收Ⅰ ~ Ⅳ级的相邻第一恒磨牙倾斜角度依次为（58.5 ± 6.4）、（61.4 ± 8.4）、（61.9 ± 9.4）、（61.7 ± 9.0）°,两者之间无显著相关性（r = 0.1,P > 0.05）。结论    上颌第一恒磨牙异位萌出时,其近中倾斜角度越小,越可能导致并加重第二乳磨牙牙根的异常吸收。     

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第一恒磨牙在萌出过程中过于偏近中可导致第二乳磨牙牙根吸收。第一恒磨牙异位萌出常常造成间隙丧失和牙弓长度减少，严重者可导致第二乳磨牙早失。第一恒磨牙异位萌出分为可逆性和不可逆性，对于不可逆性异位萌出应进行积极的治疗。治疗方法包括主动治疗和被动治疗。前者常用的方法有分牙法以及采用推第一恒磨牙向后的装置；后者通常采用截冠或拔牙的方法。本文对第一恒磨牙异位萌出的临床表现和常用的治疗方法进行了阐述。     

Root resorptions related to ectopic and normal eruption of maxillary canine teeth – A 3D study

Abstract

Objective. To assess the incidence and severity of root resorption of maxillary incisors caused by ectopically and normally erupting maxillary canines and to analyse factors influencing root resorption of incisors using cone beam computed tomography. Subjects and methods. The study sample comprised 59 patients with a total of 80 canines. Forty-six of the canines, in 37 patients, were defined as ectopic and 34 canines, in 22 patients, were defined as normal. The severity of root resorptions were analysed according to studies by Ericson and Kurol. Multiple logistics regression was used to evaluate the association between various factors and root resorptions. Results. The prevalence of root resorptions was significantly higher in the ectopic canine group, 11.0% of the central incisors and 67.6% of the lateral incisors in comparison to 0% and 36.2% in the normal erupting group. Most resorptions were defined as ‘slight’ and were located in the middle third of the root. There was a statistically significant relationship between canines located mesial to the midline of the lateral incisor and root resorption on the maxillary incisors. Conclusion. The present results show that root resorption of maxillary lateral incisors was common in patients referred to CBCT imaging due to maxillary canine eruption disturbances. Although significantly more frequent in patients with ectopically erupting canines, lateral incisor resorption was also found in association with approximately every third of the normally erupting canines. The best predictor for root resorption seemed to be location of the canine mesial in relation to the midline of the lateral incisor root.     

Does the canine dental follicle cause resorption of permanent incisor roots? A computed tomographic study of erupting maxillary canines

We performed computed tomography (CT) on 107 children and adolescents aged 9-15 years with 176 unerupted maxillary canines (152 erupting ectopically and 24 erupting normally) to determine whether there is an association between widened dental follicles of the maxillary canines and resorption of the adjacent incisors during eruption. Contiguous axial (transverse) CT scans were obtained through the maxilla in the region of the canines. The width and shape of the dental follicles were recorded, as were any contacts between the follicles and the crowns of the maxillary canines and neighboring incisors. Fifty-eight lateral incisors (38%) and 14 central incisors (9%) had some type of root resorption. The position of the maxillary canine in relation to the root of the lateral incisor varied greatly, as did the width and shape of the canine dental follicle. Follicle width ranged from 0.5 mm to 7.0 mm. The mean +/- SD width of dental follicles was, on average, larger for the ectopically positioned canines (2.9 +/- 0.8 mm) than for the normally erupting canines (2.5 +/- 0.8 mm) (P < or = .01). We found that during eruption, the follicle of the erupting maxillary canine frequently resorbed the periodontal contours of adjacent permanent teeth but not the hard tissues of the roots. We concluded that the dental follicle did not cause root resorption of permanent teeth. Resorption of neighboring permanent teeth during maxillary canine eruption was most probably an effect of the physical contacts between the erupting canine and the adjacent tooth, active pressure during eruption, and cellular activities in the tissues at the contact points, all of which are part of the eruptive mechanism. The findings also confirm an association between root resorption of deciduous canines and the dental follicles of erupting permanent canines.     

The morphological studies of root resorption of maxillary primary canines and their relation with the position of successive permanent teeth using Micro-CT

The purpose of this study is to clarify the root resorption of maxillary primary canines in relation to the development of successive permanent teeth. It was observed the maxilla of dry skulls of Indian children, using Micro-CT, and measured shortest distance between the root surface of maxillary primary canine and the bony crypt of maxillary canine. The bony crypt including successive canine was positioned almost directly above the root of primary canine and located superior to another bony crypts in the primary dentition stage. When the first molars reached the alveolar crest in addition to the primary dentition stage, the bony crypt of canine grew, showing the distal inclination of the superior margin and mesial inclination of the inferior margin. After the stage which is central incisors reached the alveolar crest, root resorption of primary canines was observed on the lingual side nearby the root apex and the bony crypt of canine was adjacent to the nasal cavity. It was quantitatively shown that the distance between the roots of primary maxillary canine and canine bony crypts reduced from central incisors reached the alveolar crest to lateral incisors reached that.     

Early and unusual incisor resorption due to impacted maxillary canines.

A very early and severe case of maxillary incisor resorption caused by impacted canines is reported. An estimated 50,000 cases of ectopic eruption and impaction of maxillary canines occur each year in the United States. Although incisor resorption due to ectopically positioned permanent maxillary canines can be swift, silent, and devastating, an effective protocol has been developed for early detection and management of this condition. Palpation and, if indicated, radiographic evaluation are combined with primary canine removal in selected cases. These strategies--particularly when used early--can prevent the vast majority of palatally impacted maxillary canines and the potentially devastating resorption of adjacent incisors.     

Inclusione dei canini mascellari permanenti e riassorbimento radicolare degli incisivi: prevenzione e aspetti medico-legali

Objectives

To discuss the risk of incisor root resorption in the presence of ectopic eruption of the permanent maxillary canines.

Discussion

Early detection of an anomalous intraosseous position of the maxillary canine is essential. To this end, patients should undergo a comprehensive clinical and radiographic assessment starting at the age 8 years.

Results and conclusions

Eruption of the ectopic permanent canines can be facilitated with early extraction of the primary maxillary canines (and possibly the primary first molars). This approach can prevent impaction (which requires more complicated, prolonged, and biologically expensive treatment) and limit the risk of root resorption involving the adjacent teeth (an event that causes irreversible damage and may give rise to medicolegal litigation).     

Deciduous canine and permanent lateral incisor differential root resorption.

When a permanent maxillary canine erupts apical to the permanent lateral incisor and the deciduous canine, resorption typically takes place only on the deciduous canine root. An understanding of this differential resorption could provide insight into the reasons for excessive iatrogenic root resorption during orthodontic tooth movement. The purpose of the present study was to examine the response of roots of permanent lateral incisors and deciduous canines to simulated resorption, and to acid and enzyme attack, reflecting the physiologic environment of an erupting permanent canine. Groups of maxillary permanent lateral incisor and deciduous canine roots were exposed to 5 combinations of Ten Cate demineralizing solution, Ten Cate demineralizing solution with EDTA, and a Type I collagenase solution. Sections of the roots were examined under a polarized light microscope. Analysis of variation of the resulting root lesions demonstrated that the lesion depths for deciduous canines were greater than those for permanent lateral incisors when averaged across 4 of the conditions (F(1,24) = 7.49, P =.0115). On average, deciduous canine roots demonstrated lesions 10% deeper than did permanent lateral incisor roots. We concluded that when deciduous canine and permanent lateral incisor roots are subjected to acid and enzyme attack, reflecting the physiologic environment of an erupting permanent canine, significantly deeper demineralized lesions are seen in the deciduous roots compared with the permanent roots. This finding may partially explain the differential root resorption during permanent tooth eruption.     

Resorption of incisors after ectopic eruption of maxillary canines: a CT study

The purpose of the study was to analyze the extent and prevalence of resorption of maxillary incisors after ectopic eruption of the maxillary canines in a sample of subjects referred to an orthodontic specialist clinic for consultation. The subjects consisted of 107 children, 39 boys and 68 girls, between 9 and 15 years of age (mean 12.5 years), with 156 ectopically and 58 normally erupting maxillary canines. All children were subjected to a basic clinical and intraoral radiographic investigation. These radiographs were supplemented with computerized tomography (CT) of the upper alveolar bones in order to get more precise information on the positions and relationships between the maxillary canines and adjacent incisors and to evaluate resorptions on the roots of the incisors. The results showed that, relative to the roots of the adjacent incisors, the crowns of 21% the ectopically positioned canines were located to the buccal, 18% to the distobuccal, 27% to the lingual, 23% to the distolingual, 5% apically and 6% between the central and lateral incisors. Ninety-three percent of the ectopically positioned canines were in contact with the roots of the adjacent lateral incisor and 19% were in contact with the central incisor. The corresponding figures for the normally erupting canines were 49%. Resorptions on the roots of the incisors adjacent to the ectopically positioned canine occurred in 38% of the laterals and in 9% of the centrals. The resorptions were graded and tended to be extensive. Among the 58 resorbed lateral incisors, resorptions were slight in 31%, moderate in 9%, and severe with pulpal involvement in 60%. The corresponding figures for the 14 resorbed centrals were 36%, 21%, and 43%, respectively. About 60% of the resorptions involved the middle and apical thirds, the tip of the apex not included. On the sides with normally erupting canines, 3 lateral maxillary incisors were slightly or moderately resorbed distally. In all, 51 of the 107 subjects with ectopically erupting maxillary canines (48%) had resorbed maxillary incisors during the eruption of the maxillary canines. There were statistically significant correlations between ectopic eruption of the maxillary canine, contacts between the teeth and resorptions on the adjacent incisors. It was concluded that resorption on maxillary incisors after ectopic eruption of the maxillary canines is a more common phenomenon than previously reported and has to be considered in all cases with seriously diverging eruption of maxillary canines. It was also concluded that the resorptions of the roots of the incisors were caused by pressure during the eruption of the adjacent, aberrant canine. Finally, it was shown that CT scanning substantially increased the detection of root resorptions on incisors adjacent to ectopically erupting maxillary canines (about 50%). The sensitivity of intraoral films was low when diagnosing the resorptions, being calculated to 0.68.     

328颗上颌恒切牙异常萌出原因的临床分析

目的分析导致上颌恒切牙异常萌出的原因,为提高诊疗水平提供理论依据。方法收集上颌恒切牙异常萌出的患者239例,共计328颗上领恒切牙,记录并分析导致上颌恒切牙异常萌出的原因,对数据进行统计学分析。结果328颗异常萌出的上颌恒切牙中,阻生或弯曲牙者64颗;上颌恒切牙已萌出,但位置异常者264颗,其中唇侧异常萌出45颗,腭侧异常萌出187颗,远中异常萌出32颗。对异常萌出的原因进行分析,上颌乳前牙根尖感染患者92例（38．5％）,上颌乳前牙外伤患者30例（12．6％）,上颌乳前牙滞留患者（非感染和外伤所致）26例（10．9％）,多生牙患者18例（7．5％）,上唇系带肥厚患者11例（4．6％）,口腔不良习惯、骨量不足等其它原因患者19例（7．9％）,另有43例（18．0％）患者合并局部或全身多种相关疾病。结论乳前牙根尖周炎是导致上颌恒切牙异常萌出的主要病因,儿童口腔医生应积极治疗乳牙疾病,去除或减轻导致上颌恒切牙异常萌出的因素,诱导儿童牙列和咬合功能的正常发育。     

A review of impacted permanent maxillary cuspids--diagnosis and prevention

As impacted permanent maxillary cuspids occur in 1-2% of the population, the general dentist should know the signs and symptoms of this condition and the interceptive treatment. Features of buccal or palatal cuspid impaction include lack of canine bulges in the buccal sulcus indicating a lingual eruption path and possible impaction; lack of symmetry between the exfoliation and eruption of cuspids that may indicate palatal or lingual impaction; and abnormal mesiodistal location and angulation of the developing maxillary permanent cuspids on radiographs. Diagnosis of impacted cuspid teeth at age 8-10 years can significantly reduce serious ramifications, including surgical exposure and orthodontic alignment as well as root resorption of the lateral incisors. In specific cases, extraction of the primary maxillary cuspids can prevent impaction of the permanent maxillary cuspids and additional sequelae.     

Can the severity of root resorption be accurately judged by means of radiographs? A case report with histology.

INTRODUCTION: Root resorption of lateral incisors caused by the pressure of erupting canines is a well-known but relatively rare problem in orthodontics and general dentistry. It is usually diagnosed on radiographs. The purpose of this article is to discuss some difficulties associated with evaluating root resorption from radiographs alone. A case report is presented as an example. METHODS: Radiographs showed that an 11-year-old girl had marked root resorption of the maxillary lateral incisors, caused by the impacted permanent canines. The incisors were to be extracted. Several months before the extractions, a canine had been surgically exposed to remove pressure from the incisor root. The lateral incisors were analyzed histologically, and the histologic findings were compared with those of the patient's mandibular first premolars, which had been extracted. RESULTS: The resorption of the lateral incisors was more severe than expected from the radiographs. The resorption extended far into the pulp. Most, although not all, root resorption areas showed histologic evidence of repair, but the amount of repair was far from functional repair levels. The mandibular first premolars had no signs of resorption, thus excluding systemic causes. CONCLUSIONS: The severity of root resorption of lateral incisors cannot be accurately judged from radiographs alone.