cementoblastoma is a relatively rare odontogenic benign neoplasm characterized by a calcified cementum - like deposit attached to the apex of the root and produced by neoplastic cementoblasts . it represents a very small proportion of all odontogenic tumors , with a percentage less than 1%1 . the world health organization first named this neoplasm " benign cementoblastoma " and also " true cementoma " in their 1971 classification . this terminology was altered in 2005 , and the benign prefix was dropped because there is no malignant neoplasm originating from cementum tissue23 . the neoplasm exhibits a slow but limitless growth pattern , and the mandible is involved more often than the maxilla15 . typically , the lesion is seen on the posterior region of the mandible and commonly involves a first molar14 . differential diagnosis should be made with condensing osteitis , osteoblastoma , odontoma , cementoossifying fibroma , periapical cemental dysplasia , and hypercementosis6 . the treatment of a cementoblastoma consists of excision of the tumor , extraction of the effected tooth , and osseous curettage . apical resection and root canal treatment of the affected tooth may be preferred as an alternative treatment that increases the risk of recurrence14 . in this report , a case of cementoblastoma with involvement of an impacted mandibular canine tooth is presented due to the extremely rare tooth and site preference for this neoplasm . a 31-year - old female was referred to our clinic for an asymptomatic lesion in the mandible that was noticed incidentally on panoramic radiograph during a dental examination performed by her dentist . the patient 's medical history was unremarkable , and there was no reported history of maxillofacial trauma . the clinical examination revealed a barely detectable , hard , non - tender area of swelling on the buccal side of the right mandibular canine area and a persistent deciduous right mandibular canine tooth . a radiopaque mass that had a close relationship with the root apex of the impacted mandibular right canine tooth was detected on the panoramic radiograph . cone - beam computed tomography ( cbct ) was determined to be appropriate for further radiological examination of the mass ( galileos comfort plus cbct unit ; sirona dental systems inc . a homogenous hyperdense deposit with a size of 9.59.56.5 mm was seen in the mentioned area of the cbct images . significant thinning on the adjacent buccal cortical bone was detected , but there was no cortical perforation . the oblique sagittal images showed that the deposit was continuous with the root apex of the impacted mandibular right canine tooth , and there was a well - defined hypodense border between the deposit and surrounding bone.(fig . 1 ) clinical and radiological examination led to the diagnosis of cementoblastoma , and surgical excision of the mass with the involved tooth was planned . the lesion was removed surgically with extraction of the involved canine tooth through an intraoral approach under general anesthesia . 2 ) , which revealed dense , mineralized , cementum - like material and vascular soft tissue areas that consisted of cementoblasts.(fig . cementoblastoma most commonly occurs on the posterior region of the mandible and is often attached to the root of an erupted permanent premolar or first molar14 . on rare occasions , an impacted tooth , multiple teeth , or a deciduous tooth may be affected as well1578 . to our knowledge , there have been 8 reported cases of cementoblastoma that developed on anterior jaws in the literature910111213141516 , with only two of them located in the mandible910 . one case was related to an impacted permanent incisor9 , while the other case was related to a deciduous incisor10 . this present case is unique due to its occurrence in the anterior mandible and involvement of an impacted mandibular canine tooth . pain , tenderness , and swelling are present in most patients with cementoblastoma , although the lesion can be asymptomatic . the patient was asymptomatic , and the lesion was discovered incidentally on a panoramic radiograph . radiographically , cementoblastoma appears as a well - defined circumscribed radiopaque or mixed mineralized mass fused to one or more tooth roots of the involved tooth and has a radiolucent rim1 . though rate , some tumors , especially recurrent ones , may be completely radiolucent due to reduced mineralization317 . the tumor may cause various amounts of external resorption , bony expansion , displacement of adjacent teeth , and in some cases , cortical perforation , jaw deformity , and pathologic fracture146 . cbct images show the radiopaque mass attached to the roots of the involved tooth and provide detailed information about the presence of buccal and/or lingual perforations . in the present case , cementoblastoma was observed on cbct as a well - defined radiopaque mass fused to the root of the mandibular canine without cortical perforation.(fig . 4 ) simple excision of the lesion and extraction of the involved kartooth are sufficient treatments1 . a 37.1% recurrence rate has been recently reported , especially for cases with aggressive features4 . in the present case histologically , the tumor tissue consists of acellular and irregular layers of a calcified cementum - like mass attached to the root of the tooth , with trabecular calcified bone - like areas and cementoblasts observed in the calcified matrix and fibrovascular stroma . the histopathologic presentation of cementoblastoma closely resembles that of osteoblastoma , but can be distinguished by fusion of the tumor with the involved tooth118 . during the differential diagnosis of cementoblastoma , there are some clinical and radiographic details that have to be considered for each similar disease . condensing osteitis is an inflammatory sclerotic bone change of the periradicular region with dental inflammatory stimulus , as is not found in cementoblastoma . the periradicular sclerotic area resembles cementoblastoma , but the absence of a radiolucent rim and tooth - mass continuity with an irregular and poorly defined shape of the sclerotic area and inflammatory pulpal changes with associated symptoms are remarkable for condensing osteitis . osteoblastoma has very similar clinical and radiographic findings but tooth - mass continuity does not exist . generally , osteoblastomas have more irregular mass radiopacity than cementoblastomas . also most osteoblastomas have osteolytic borders and cause persistent pain19 . additionally , osteoblastoma may have more aggressive clinical features than cementoblastoma . odontomas have a radiolucent rim like cementoblastomas , but the mass in the capsule consists of rudimentary tooth - like deposits or an irregularly shaped deposit that exhibits radiographic opacity similar to teeth . cemento - ossifying fibromas have the same site preference as cementoblastomas . unlike cementoblastomas , bilateral expansion and mixed radiolucency with sclerotic borders are seen with this fibrous - osseous lesion19 . periapical cemental dysplasia is usually seen on the anterior mandible with the involvement of multiple teeth , which is not seen with cementoblastomas . the mature stage of this disease may resemble cementoblastoma minus the tooth - mass continuity . in conclusion , cementoblastoma usually involves an erupted permanent tooth and most commonly occurs in the posterior region of the mandible . this case report presents a unique example with an extremely rare tooth and site preference for this neoplasm . in addition , the involvement of the impacted tooth at this mentioned site is another rarity . other than these mentioned differences , the observed clinical , radiological , and histopathological features and prognosis of the neoplasm were similar to all of the other cases of cementoblastoma found in the literature .
a benign cementoblastoma , which is another name for a true cementoma , is a rare neoplasm that develops from odontogenic ectomesenchyme . 
 it is characterized by a mineralized mass attached to the apex of the root produced by neoplastic cementoblasts . 
 more than 75% of cases arise in the mandible , with 90% of them manifesting in the molar and premolar regions . 
 this neoplasm occurs most commonly in children and young adults , with males being affected slightly more than females . 
 radiographically , the tumor is observed as a well - defined radiopaque mass that is fused to a tooth root and is surrounded by a radiolucent rim . 
 the treatment of benign cementoblastoma consists of removal of the lesion and extraction of the affected tooth . 
 this report presents an unusual case of benign cementoblastoma in a 31-year - old female , presenting as a densely mineralized mass seen at the apex of the impacted right mandibular canine tooth on radiographs .