tooth impaction is a condition in which a tooth fails to erupt into normal position beyond the expected time . generally two types of impaction exist : 
 primary , the tooth has never appeared into the oral cavity which is rare;secondary , defines teeth which have once erupted , but subsequently appear to have clinically regressed from this position [ 24 ] . primary , the tooth has never appeared into the oral cavity which is rare ; secondary , defines teeth which have once erupted , but subsequently appear to have clinically regressed from this position [ 24 ] . in the literature , several etiologies have been explained for tooth impaction . local factors such as trauma , odontogenic cysts and tumors ( dentigerous cyst ) , odontomas , ankylosis , malformation of the tooth germ , dentofacial incoordination and infection . the aim of this paper is to present a case with inverted impacted primary maxillary central incisors . a 4-year - old girl was referred to the pediatric dentistry department of tehran university of medical sciences with the chief complaint of upper anterior teeth missing and esthetics problem . her parents stated that her teeth have never erupted and when their daughter was 89-months - old she fell from the stairs and after that her upper lip was swollen . iq of the patient was normal and the family and medical histories were not remarkable . in the intraoral examination , the child s occlusion was mesial step and there were some carious teeth in the oral cavity . the maxillary incisors were absent and gingival tissues in this region had a normal color and seemed bulgy without any pain in palpation ( figure 1 ) . radiographic examinations showed inverted incisors with open apexes and incomplete roots and odontoma - like particles were seen near the permanent maxillary incisors ( figure 2 ) . because the child was not cooperative and she needed other dental procedures , surgical removal of the teeth under general anesthesia first all carious teeth were restored . then after elevation of the mucoperiosteal flap in the anterior sextant of the maxilla , the teeth were removed . the teeth were rotated 180 and the palatal and incisal sides were located in the buccal and apical , respectively . the molds were then used to create nance appliance because the child was not cooperative and fix appliance was chosen ( figure 4 ) . after soft tissue healing , the nance appliance was delivered to the child and oral hygiene instructions were explained to the parents and the child . moreover , follow - up visits were scheduled for monitoring of the patient ( figure 5 ) . in the follow - up visit , the nance appliance was removed and the abutment teeth were cleaned and fluoride therapy was done , then the nance appliance was recemented in her mouth . impaction of permanent teeth is a usual finding , but primary teeth impaction is rare occurring in 1:10,000 of the cases [ 10 , 11 ] . a few cases of inverted impacted primary maxillary [ 10 , 12 ] and mandibular central incisors have been reported [ 4 , 13 ] . in none of them trauma has been mentioned , although it is not completely ruled out as an etiological factor . in our case , the parents have recalled trauma to the teeth , but the impaction was primary , because the teeth have never been seen in the oral cavity . however , trauma can displace tooth germ before erupting and may have impact on the unerupted developing teeth . the outcome of traumatic injuries to the primary teeth is based on personal belief and experience rather than evidence based documents . partial or complete arrest of root formation is a rare complication after trauma to primary teeth , affecting involved permanent teeth . in this case , the root formations of both primary central incisors were stopped . the close proximity of the developing permanent teeth to the root of the primary teeth may result in an injury to the developing permanent successor . in our case anterior primary maxillary teeth impactions are problematic for both parents and the physician because of its effect on the patient 's speech , esthetics , function and psychology . four treatment options have been suggested for impacted teeth : observation , intervention , relocation and extraction . in this case , the teeth were removed because they were inverted and normal eruption of the teeth would not occur and it seemed that they may interfere with the underlying permanent teeth development and eruption . for esthetically and psychological reasons although tooth impaction rarely happens in primary teeth , when dentists encounter to delay eruption , it is important to take a medical and dental history and to evaluate the problem with radiographic examination to rule out or confirm missing or other anomalies . in this case ,
tooth impaction rarely occurs in primary dentition . 
 most of the primary teeth impactions are seen in second molars . 
 the purpose of this article is to present a 4-year - old girl with bilateral impaction of inverted primary maxillary central incisors which trauma had displaced their tooth germ before erupting .