From Volume 16, Issue 2, April 2023 | Pages 92-94
This article describes a case of bilateral impaction of upper second premolars into the upper first permanent molars in a 12-year-old female patient. The extraction of both resorbed upper first molars, and subsequent orthodontic management is described.
Impaction of teeth may be seen with arch length discrepancy, premature primary tooth loss, the presence of supernumerary teeth, cleft palate and other conditions such as cleidocranial dysplasia.1 A tooth that remains partially or fully embedded in bone or mucosa for 2 years post physiological eruption time is defined as impacted.2 Third molars are the most commonly impacted teeth followed by maxillary canines, and second premolars.3 Impacted molar teeth, excluding the third molar, are least prevalent.4
Root resorption is often associated with impacted or unerupted teeth.5 The upper lateral incisor is the most common tooth to suffer from resorption owing to the impaction of an upper permanent canine.6,7Incidence of resorption of second molars is low, even when third molars are the most commonly impacted tooth in the arch.8 In contrast to upper lateral incisors, root resorption of an upper permanent molar from an upper permanent second premolar is relatively rare.9 The second premolar usually erupts between the ages of 10 and 12 years. They are among the final teeth in the succession pattern to erupt.10 The literature shows root resorption can occur on molar teeth with ectopic and non-palpable premolars in line with the arch, but this is a rare outcome.11
Palpation and radiographic imaging to determine location of teeth at risk of impaction is important. The pathological consequences of tooth impaction are difficult to predict. If a tooth is partially erupted, or unerupted yet palpable, it is not considered likely to cause root resorption of the adjacent teeth.5
This case describes bilateral, palatally impacted and partially erupted upper premolars causing root resorption of both upper first permanent molars, therefore having consequences on orthodontic management.
This case reports on a medically fit and well 12-year-old female patient of European origin who attended Bristol Dental Hospital asymptomatically, for an orthodontic assessment and subsequent treatment. The patient's general dental practitioner (GDP) had observed bilateral maxillary buccal segment crowding associated with partially erupted palatally positioned second premolars (Figure 1).
A dental panoramic tomograph (DPT) provided by the patient's GDP highlighted concerns relating to the impacted upper second premolars with evidence of radiolucencies, especially on the mesial aspect of the UR6 (Figure 2). Plain film intra-oral radiographs, including right and left bitewings, along with upper posterior peri-apical views (Figure 3), were taken indicating radiolucencies on the mesial aspect of the UR6, absence of apical pathology or coronal caries. Owing to the potential for overlap on the plain film, and for accurate visualization, a computed tomograph (CT) scan was taken to assess the three-dimensional nature of the UR6 and UL6. The CT scan confirmed the presence of the extensive root resorption of the mesial aspects of both upper right and upper left first permanent molar teeth (Figure 4). Clinically the patient was caries free, with good oral hygiene. Fissure sealants had been placed for caries prevention in the primary dental care setting.
A diagnosis of crowding with bilateral impaction of upper second premolars with associated root resorption of both upper first permanent molars was made.
The aims of orthodontic treatment were to alleviate crowding and align the upper arch. This was to be achieved by:
Figure 5 shows the extent of mesial root resorption and soft tissue ingress of both upper extracted first permanent molars. Following surgery, both upper second premolars fully erupted (Figure 6) and fixed appliances were placed to align and de-rotate these teeth, as well as aligning both upper lateral incisors. Figure 7 shows the patient after successful treatment prior to debonding of the orthodontic appliance. There was optimal space closure, considering the amount of space closure required after the extraction of the maxillary first permanent molars.
This is an unusual case. The patient presented asymptomatically with an aesthetic and functional concern regarding both upper second premolars, which were palatally positioned. There had been no history of early primary tooth loss or presence of supernumerary teeth.
Had the extraction plan been made without three-dimensional imaging and up-to-date radiographs, the impacted second premolars could have easily been the teeth of choice for extraction. This would have allowed a well-aligned dental arch with minimal orthodontic input. Significantly, this would not have highlighted the severely compromised and poor prognosis of the first permanent molars, which would have required future extraction, and likely prosthetic intervention.
Owing to the extent of the pathological destruction by these palatally positioned yet erupted upper second premolars, the case highlights the importance of comprehensive assessment and monitoring of all palatally positioned premolars.
Butler et al reported the rarity of cases of upper molar root resorption as a consequence of palpable yet impacted premolars.12 Ectopic premolars can lead to impaction and buccal segment crowding and, in rare cases (as described here), resorption of the permanent first molar. Only mild cases of ectopic second premolars are self-correcting. Early intervention is usually required.11 Where there is no sign of spontaneous self-correction after a short observation period, active treatment is advised. This case report clearly demonstrates that even when upper second premolars have started to erupt into the arch, resorption of the upper first molars may have already occurred. In this case, eruption of the second premolars was not delayed nor was their eruption outside the chronological pattern. Three dimensional radiographic investigation proved essential to confirming the diagnosis, thus enabling optimal treatment planning and outcome.
Palatal impaction of maxillary second premolar teeth is relatively rare and can pose challenges for treatment planning. Despite mandibular premolars accounting for 24% of all dental impactions, literature on management of these cases is not extensive.13 There is even less guidance on the management of impacted maxillary premolars. This case highlights the importance of early detection of ectopic premolar teeth and the significance of thorough radiographic imaging prior to planning extractions to identify potential resorption of adjacent teeth and to ensure that an appropriate treatment plan is formulated.
