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Paper text:
idiopathic external root resorption is a rarely reported condition which has been observed in single or multiple teeth .
orthodontic therapy , trauma , periapical or periodontal inflammation , tumors , cysts , occlusal stress , impacted and supernumerary teeth , transplantation and reimplantation are among the local causes that could lead to pathological root resorption .
hyperparathyroidism , hypoparathyroidism , hypophosphatemia , hyperphosphatemia , gaucher s disease , paget s disease of the bone , goltz syndrome , papillon - lefevre syndrome , anachoresis , turner syndrome as well as dietary habits have been reported as related endocrine disturbances and systemic causes . by definition ,
if an etiological factor can not be identified for root resorption , the term  idiopathic  is applied .
it should be differentiated from the pathologic type and merits to be recognized by a clinician .
two types of idiopathic root resorption have been observed ; namely , apical and cervical .
cervical root resorption starts in the cervical area of the teeth and progresses toward the pulp . in the apical type
the resorption starts apically and progresses coronally causing a gradual shortening and rounding of the remaining root .
patients with idiopathic root resorption are commonly asymptomatic clinically with an occasional complaint of tooth mobility , so the condition is usually found in routine radiographic examination . according to literature review of cholia et al , the idiopathic apical root resorptions were slightly more common in the upper jaw and molar region than in the lower jaw and single root teeth ; however , these differences were not statistically significant .
minimal apical external root resorption may be present in all permanent teeth   and has been attributed to a variety of causes . however , up to now only numerated cases of idiopathic apical root resorption have been reported in the literature .
this article describes a case of idiopathic apical root resorption in which no cause could be identified or any reason determined for its occurrence .
this article describes a case of idiopathic apical root resorption in which no cause could be identified or any reason determined for its occurrence .
the 17-year - old healthy and normally developed iranian male student was referred to oral radiology clinic for routine radiographic examination .
multiple apical root resorptions was found accidentally on the panoramic view in teeth 11 , 12 , 14 , 22 , 36 , 37 , 45 and 46 ( fig 1 ) and diagnosis was confirmed taking periapical radiographs ( fig 2 ) .
haematological investigations including complete blood count as well as calcium , phosphorus and alkaline phosphatase were within the normal range , so endocrine diseases such as hyperparathyroidism , hypoparathyroidism , hypophosphatemia , hyperphosphatemia and paget s disease was ruled out . since abdominal ultrasonography was unfruitful , possibility of gaucher s disease was eliminated . in papillon - lefevre syndrome ,
the history of premature tooth loss associated with hyperkeratosis is remarkable , of which none of them were recognized in the patient . furthermore , turner s syndrome is restricted exclusive to females .
the patient recalled no history of early tooth loss in parents , grandparents , or siblings .
clinical and ( dental ) examination revealed normal soft tissues without any supra or subgingival calculi or abnormal pocketing .
there was no restoration and the only carious lesion was in tooth 37 , the mandibular left second molar while clinical and radiographic examinations failed to reveal dental caries or unusual pulp chamber configurations in the involved teeth .
there was no history of orthodontic therapy and occlusion demonstrated class molar and canine relationship with normal overjet and overbite .
the patient was asked to follow proper oral hygiene instructions and periodic follow up was suggested .
few cases of multiple idiopathic apical root resorption ( miarr ) exist in the literature .the first well documented report was in 1930   and since then more cases were presented [ 1,2,3,].with no absolute etiological factor identified we considered this case as multiple idiopathic apical root resorption .
no local etiologic factor was detected and clinical appearance of the teeth and periodontium were normal . regarding the number of affected teeth in literature review which were about eighteen on average , , in this report only eight teeth were involved .
it may be related to the age of the patient compared with other reported cases .
the present case was among a few cases who were under 21 years old at the time of detection .
the condition has been reported to have a predilection for young females   and 14 cases of miarr have been were presented in females till now .
in contrast to the higher clinical incidence of pathological root resorption in females , some published papers reported a predilection of idiopathic root resorption for men . in attempt to rule out the possible role of genetic as an etiologic factor ,
differentiated blood count , calcium , phosphorus and alkaline phosphatase were within normal range . due to the mild degree of resorption , limited number of involved teeth and lack of clinical discomfort , no treatment was advised .
schatzle et al reported a case of progressive generalized apical root resorption in a 17-year- old female .
two panoramic radiographs were taken to follow progression of root resorption . as they had to extract three involved teeth ,
histologic examination showed thickening of cementum layer and accelerated deposition of cellular cementum which normally covered the apical half of the root and furcation .
as mentioned above , occlusal stress is one of the contributing factors responsible for resorption which can result in dystrophic changes in periodontal ligament , alveolar bone , cementum and pulp .
moreover , significant reduction in root and crown length and stunted , short , small crowns and roots have been reported in association with down syndrome .
sogur reported an excessive production of bone surrounding absorbed roots as a compensatory response to osteoclastic activity which had not been seen in previous cases .
although the minimal apical root resorption was found in tooth 37 , due to the presence of the carious lesion we did not consider it as an idiopathic process .
a number of treatment methods have been reported useful in animal studies to be useful to arrest this type of resorption ; none have of which been shown effective clinically in the human . .
the aim of this case report was to present a case of multiple idiopathic apical root resorption which is a rare condition in a 17-year - old adult male . 
 external root resorption of the permanent teeth is a multifactorial process . 
 well - recognized causes of apical root resorption in permanent teeth include orthodontic therapy , trauma , periapical or periodontal inflammation , tumors , cysts , occlusal stress , impacted teeth , systemic conditions , endocrine imbalances and dietary habits . when none of these causes are present , it is termed idiopathic root resorption which may be either cervical or apical . 
 multiple idiopathic apical root resorption is a rare condition which is usually detected as an incidental radiographic finding . 
 however , it may cause pain and mobility in severe cases .