Introduction
Impaction is a condition in which complete tooth eruption is delayed by contact with another tooth [1]. It is characterized by dental absence in the arch after its usual period of eruption. Unerupted teeth are often encountered in the mixed dentition stage [2]. Maxillary central incisors normally erupt between the age of 8 and 10 years and delayed eruption has an adverse effect on aesthetics, function, and speech [2,3]. It may result in adjacent tooth migration, space loss, and midline deviation. The primary cause of central incisor impaction can be due to trauma to the primary teeth, and mechanical obstruction which might be due to the presence of supernumerary teeth, odontomas, or cysts developed within the eruptive path of the tooth [3]. The prevalence of impacted maxillary central incisors in the age of 6–12 years old is 13% [4]. Eruption of the maxillary incisor is delayed if the eruption of the contralateral incisor occurred 6 months earlier, the lower incisors have erupted >1 year earlier or there is a deviation from the normal sequence of eruption [5].
Diagnosis of impacted incisors comprises of clinical examination to identify retained deciduous teeth and palpation of the alveolar region. The clinician may encounter a painless, incompressible, palatal, or vestibular fibro mucosal protuberance. Early diagnosis of transposition in tooth development and impaction is essential and greatly influences the prognosis [1,3]. Intraoral radiographs can confirm a diagnosis. Periapical views and/or an upper standard occlusal radiograph determine the presence and position of maxillary incisor teeth and any underlying developmental anomalies or pathology. Cone-beam computed tomography (CBCT) provides a clear 3-D view of the impacted teeth and the associated structures [3,4]. CBCT is valuable in treatment planning, as the degree of aberrant crown root angulation can be assessed and imaging used to plan the optimal direction of traction required, ensuring that both the crown and root are maintained in alveolar bone during alignment of the tooth. Depending on the exact position of the impacted incisor, orthodontic movement and positioning in the dental arch can vary widely [4,5].
The 2 × 4 appliance comprises four brackets bonds on the maxillary incisors, bands on the first permanent maxillary molars, and a continuous archwire [6]. Active interceptive measures in mixed dentition treatment are usually confined to the correction of anterior and posterior crossbites and alignment of ectopic incisors. Continuous archwires are used to provide complete control of the anterior dentition as well as a good archform [6,7]. The deciduous teeth are generally unsuitable for bonding, therefore supporting steel tubing is placed in the long spans between the lateral incisors and first permanent molars. This appliance allows rapid correction of many incipient malocclusions in a single short phase of fixed appliance therapy in the early mixed dentition stage [6–8].
The rationale of the 2 × 4 orthodontic treatment is to prevent malocclusion near future through the procedure of interceptive orthodontics.
Case Report
History and diagnosis
A 10-year-old male was reported to the Department of Paediatric and Preventive Dentistry with a chief complaint of missing upper front teeth from two years. No significant medical or dental history was recorded. On intraoral examination, the patient had a class 1 molar relationship bilaterally with a missing maxillary right central incisor (Fig. 1). A bulge could be felt in the anterior region.
Radiographic examination
A routine intra-oral periapical radiograph was done and found that impacted. A panoramic radiograph revealed an impacted right central incisor (11) and supernumerary tooth a well. CBCT scan was done to evaluate the shape and exact position of the supernumerary tooth which revealed that it was lying behind the mildly oblique positioned impacted right central incisor and in between the left central incisor and right lateral incisor (Fig. 2). The tooth appears to be malformed and placed rotated. The palatal aspect of a crown of #11 appears to be lying in proximity with a labial aspect of the crown of #12 and crown of supernumerary tooth. The apical third of root of #11 appears to be positioned more palatally. The root appears to be directed toward floor of nasal cavity not lying in proximity to any tooth. There is no evidence of any other pathology seen.
Figure 1.
Pretreatment intraoral photographs.
Figure 2.
Pretreatment CBCT.
Diagnosis
- Impacted central incisor in relation to 11.
- Supernumerary tooth (mesiodens) is seen between 11 and 12.
Treatment plan
The cause of impaction was established as an obstruction to the path of eruption due to supernumerary teeth. The open surgical procedure was selected because the crown was covered with palatal mucosa. The treatment was planned in two stages. The first stage consisted of surgical extraction of the impacted supernumerary tooth. The second stage consisted of surgical exposure of the impacted central incisor in relation to 11. Both the stages were done on the same day within an hour and traction of the impacted central incisor with the fixed 2 × 4 orthodontic appliance was planned which was placed for four months.
Figure 3.
Surgical removal of supernumerary teeth.
Treatment
The whole mouth region is sterilized using a swab dipped with Betadine® (povidone iodine 10% w/v). Infraorbital and nasopalatine nerve blocks were administered. Horizontal incision followed by buccal incision was given using BP blade no. 15 and the flap was raised with a periosteal elevator (Fig. 3). Supernumerary teeth were extracted followed by suture placement. Antibiotics and analgesics were prescribed for a week for the patient. The following antibiotic and analgesic were given—Rx Augmentin DUO oral suspension 228 mg/5 ml was the choice given to the patient on taking medication twice in 24 hours and Rx Ibugesic Plus Oral Suspension 100 mg/10 ml was taken three times in 24 hours. The patient was recalled after seven days for suture removal.
After 7 days impacted #11 was palpated and exposed by preparing window followed by 0.022” slot bracket placement. The permanent first molars received orthodontic bondable molar buccal tubes (stainless steel prefabricated) and all permanent incisors received edgewise brackets with 0.022” slot (MBT orthodontic bracket system) (2 × 4 appliance). A 0.012 NiTi arch-wire was placed in the brackets for initial movement and held for 4 weeks, after which a sequential change of wire from 0.014 NiTi arch-wire to 0.016 NiTi arch-wire and finally to 0.018 NiTi arch-wire was done at 16-week intervals. O rings were used to keep the arch-wire in place and changed along with arch wire. A power e-chain was placed for minute space closures along with 0.016 NiTi arch wire (Fig. 4). Finally, 0.019/0.025 SS wire was placed at the consolidation phase for 1 month. The incisors were appropriately aligned at the end of five months, with the closure of the midline diastema. The brackets were removed once all the teeth were in normal alignment, and a lingual bonded retainer was placed on the four anterior teeth to avoid relapse (Fig. 5). The patient is kept on follow-up for six months and reviewed regularly.
Figure 4.
(A) Surgical window preparation and bonding of 0.022” slot bracket MBT bracket, (B) initial wire placement of 0.012 NiTi, (C) change Of wire 0.014 NiTi, (D) change of wire 0.016 NiTi, and (E) change of 0.018 NiTi wire with e-chains.
Discussion
Supernumerary teeth or hyperdontia can be defined as teeth that exceed the normal dental arch, regardless of their locations and morphologies [6]. It is more common in the central region of the upper or lower jaw; however, its occurrence in the mandible is rare [7]. Mesiodens is the most common type of supernumerary teeth and is in the midline between the two upper central incisors. Its prevalence in the general population ranges between 0.15% and 1.9% and it is reported to be more common in males rather than females [8]. Supernumerary teeth are classified based on morphology (conical, tuberculate, and supplemental), location (mesiodens, paramolar, distomolar, and parapremolar), position (buccal, palatal, and transverse), and orientation (vertical or normal, inverted, transverse, or horizontal) [9]. In our case, it was a conical, palatal, and upright impacted mesiodens.
Although abundant information is available on normal tooth development, the genetic etiology and molecular mechanisms that lead to congenital deviations in tooth number have not been clearly understood [6–8]. The literature reports three theories concerning the cause of mesiodentes, but this subject remains controversial [7]. The first one was a phylogenetic relic of extinct ancestors who had three central incisors known as phylogenetic reversion (atavism) [7,8]. The second theory known as dichotomy suggests that the tooth bud is split to create two teeth, one of which is the mesiodens [5,6]. The third theory involving hyperactivity of dental lamina which was the most widely supported [7,8]. Although no investigation proved the hereditary condition of mesiodens, genetics are also thought to contribute to its development, as such occurrence has been diagnosed in twins, siblings, and sequential generations of a single family [8]. Sedano and Gorlin proposed a genetic theory in which mesiodens is an autosomal dominant trait with a lack of penetrance in some generations [8]. It has been suggested that environmental factors might have an influence on genetic susceptibility which could probably be a cause for negative family history in our case [9]. A sex-linked pattern has also been proposed, as males are affected twice as frequently as females [10]. Mesiodens are frequently associated with several craniofacial disturbances, including cleft lip and palate, cleidocranial dysostosis; and to a lesser extent with Gardner’s syndrome or chondroectodermal dysplasia [9].
Figure 5.
Final after debonding
For preoperative examination, intraoral and panoramic radiography has been used. However, alone, they are insufficient for determining the exact location of supernumerary and impacted teeth, due to the image superimposition. In the present case, CBCT provided valuable information that helped us to determine the morphology and the exact 3-D position of the mesiodens, and the permanent maxillary impacted right central incisor. Furthermore, supernumeraries can be captured with CBCT at a significantly lower radiation dosage in three planes and in relation to nearby systems. For this reason, especially in situations with numerous impactions, we advise frequent use of CBCT for the treatment of extra teeth. The thorough images in three planes produced by CBCT can benefit surgeons in deciding on the best surgical strategy, identifying the tooth that has to be evacuated, and reducing the amount of surgical stress on the surrounding soft and hard structures [7–9].
The 2 × 4 appliance is one type of fixed orthodontic appliance, it can be used in different clinical situations with only minor alterations in the appliance design. It allows a well-controlled 3-D tooth movement [10]. However, this appliance may not be effective if there are only a few teeth available in the dentition. Fewer teeth will now no longer permit the right sitting of the lengthy span arch wire, which might also additionally grasp and dislodge from its brackets or reason soreness to the patient. Usage of those appliances has no interference withinside the everyday activities of sufferers which include mastication, speech, and oral comfort. There also are no principal problems associated with appliance dislodgement, treatment compliance, and lack of appliance for the reason that those are fixed appliances [11–14].
For the treatment, it depends on the type and location of the supernumerary teeth and on its potential effect on the adjacent hard and soft tissue structures. The majority of delayed permanent incisors erupt spontaneously if sufficient space is created at the time of removal of the supernumerary tooth and maintenance of postoperative space is needed [5]. However, if there is no space for a delayed tooth, we must re-establish it by orthodontic treatment.
Conclusion
The above-discussed case showed that 2 × 4 orthodontic appliances are versatile appliances that can correct malposition teeth during the mixed dentition stage when other removable appliance methods cannot perform the required task. The advantages of this type of appliance are significant and those include:
- Bodily movement of teeth if spaces need to be created for an instanding incisor or recreated for an impacted late erupting incisor.
- Torque of the incisor roots palatally to decrease the chance of relapse, as well as maximize the aesthetic result.
- Efficient and effective derotation of incisors.
Conflict of interest
Nil.
