Authors: Dr. Priyanka Grewal,Dr. Ritu Namdev,Dr. Samir Dutta.
A mesiodens frequently delays and interferes in the eruption of maxillary central incisors. Here are 4 four cases of mesiodens causing rotation/ectopic eruption of the permanent maxillary central incisor/incisors. Early extraction of mesiodens followed by timely correction of the affected permanent tooth is recommended using simple interceptive fixed orthodontic by 2x4 appliances, thereby lessening the chances of a more complex surgical and orthodontic treatment in future.
Numerical superiority in a dentition when compared to a normal situation is known as Hyperdontia. The prevalence of supernumerary teeth in various populations is reportedly between 0.1 to 3.6% with a male to female ratio of 2:1, of which mesiodens account for approximately one-third of these cases. The occurrence of supernumerary teeth in the Indian population is 87% with one supernumerary tooth, 12% with two and 1% with multiple supernumerary teeth.
Mesiodens occur more commonly in the permanent dentition (0.1 – 3.6%) when compared to that of primary dentition (0.02-1.9%).1
According to the data available, mesiodens can delay or prevent eruption of central incisors in 26-52% of cases, cause ectopic eruption, displacement or rotation of a central incisor in 28-63% of cases, and labial displacement of incisors in 82% of cases.2
The obstructed incisor often erupts spontaneously after removal of the obstruction from its path of eruption, if sufficient space is available in the dental arch. Complications involving the late treatment of rotated permanent incisors include dilacerations of the developing roots, root resorption, loss of tooth vitality, compromised oral hygiene.3,4
Treatment may vary from extraction of supernumerary teeth to extraction followed by orthodontic correction in order to establish a good occlusion. Evidence seems to suggest that a short course of orthodontic treatment in the mixed dentition may improve function and aesthetics, reduce the potential for teasing and remain relatively stable once the appliance is removed. The 2×4 and 2×2 appliance, used in presented case series, are versatile, easy to use and well tolerated by all patients. These appliances, when used correctly, will give a controlled approach to tooth movement in all three dimensions and predictable outcome.
The case report documents four cases of mesiodens causing torsiversion and ectopic eruption of central incisor/incisors. 2X4 and 2X2 fixed orthodontic appliance is used in all cases to correct malocclusion of central incisors following surgical extraction of mesiodens.
An 8 year old boy reported with complaint of unesthetic appearance of upper front teeth. Clinical examination revealed 90o clockwise rotation of 21, conical erupted mesiodens presented on the left side of midline and soft tissue buldge was seen associated with unerupted 11 on the right side of midline (fig1). A palatal buldge was there in relation to unerupted 11. Maxillary occlusal view showed presence of another supernumerary in inverted position in relation to 11(fig2). Buccal object rule was applied and tooth was found to be in palatal position. Surgical extraction for impacted mesiodens and extraction for erupted one followed by orthodontic correction of rotated incisor using 2X4 fixed appliance after eruption of 11, was planned. After explaining treatment plan and taking inform consent from parents, extraction of left mesiodens and surgical extraction of right impacted mesiodens was carried out by raising palatal flap (fig 3 & fig 4). Patient was kept on follow up for complete eruption of 11 for 4 months. After 4 months bands were placed on 16 and 26 and metallic MBT brackets were bonded to 11, 12, 21 and 22. A palatal button was placed on 21 for application of torque. O.12 light NiTi wire was used for initial alignment and couple was created using elastic from 21 to 26 palatally and 21 to 11 labially (fig 5). In 7 months rotation of 21 was corrected and midline space was closed completely (fig 6). Patient is in retention phase.
|Fig 1- clinical picture showing erupted conical mesiodens and rotated 21 in case 1||Fig 2- maxillary occlusal view showing impacted inverted mesiodens in relation to 11 in case 1||Fig 3- intraoperative picture of palatal flap depicting exposure of impacted mesiodens palatal to 11 in case 1|
|Fig 4- extracted twin mesiodens in case 1||Fig 5- 2X4 appliance in place along with palatal button on 21||Fig 6- postoperative picture showing derotation of 21 in case 1|
A 9 year old boy presented with misaligned upper right front tooth. Above 90o clockwise rotated 11 was noted on clinical examination (fig 7). Intraoral periapical radiograph of the region confirmed presence of twin mesiodens in which right one lying horizontally. Buccal object rule was applied and labial position of right mesiodens and palatal position of left mesiodens was determined (fig 8). Surgical extraction of mesiodens was completed by raising buccal and palatal mucoperiosteal flap (fig 9 & fig 10). After complete healing, brackets were bonded to all incisors along with palatal button on 11 palatally and banding of 16 and 26 was done. A torque was created between 11 and 16 labially and 11 and 26 palatally (fig 11). Rotation was corrected in 6 months resulting in complete alignment of incisors (fig 12).
|Fig 7- clinical picture showing anticlockwise rotation of 21 in case 2||Fig 9- surgical exposure of impacted mesiodens||Fig 10- extracted mesiodens in case 2|
|Fig 11- 2x4 appliance placement and torque application in case 2||Fig 12- postoperative picture showing derotation of 21 in case 2||Fig 13- clinical picture showing twin erupted mesiodens causing rotation of central incisor in case 3|
A 10 year old boy came complaining of excess teeth in upper front region along with misalignment. Clinically, twin erupted mesiodens were noted in between anticlockwise rotated 11 and 21 (fig 13). Radiograph showed no other impacted supernumerary associated with area of concern (fig 14). After extraction of both mesiodens, bracket and palatal buttons were placed 11 and 21 and molars were banded. Torque was created on both the incisors (fig 15). In 6 months complete derotation of central incisors was completed (fig 16).
|Fig 14- intraoral periapical radiograph showing erupted mesiodens||Fig 15- 2x2 appliance placement and application of torque to central incisors in case 3||Fig 16- postoperative clinical picture showing derotation of both central incisors in case 3|
A 9 year old male presented with complaint of outward placement of upper left front tooth. On clinical examination, an erupted mesiodens palatal to 21 and labially displaced 21, were noted (fig 17). Maxillary occlusal view excluded the possibility of another mesiodens (fig 18). After extraction of mesiodens, all maxillary incisors were bonded with bracket and molars were banded (fig 19). Sequential light wires were used for alignment.
|Fig 17- clinical picture depicting erupted mesiodens palatal to 21 and labial displacement of 21 in case 4||Fig 18- maxillary occlusal view showing no other impacted supernumary tooth||Fig 19- 2x4 appliance placement in case 4|
|Fig 20- postoperative picture of case 4|
The term mesiodens was coined by Bolk (1917) to denote an accessory or supernumerary tooth situated in between the maxillary central incisors.5 The aetiology of the ST however remains unclear. Several theories have been suggested for their occurrence such as the ‘phylogenetic theory’ (Smith, 1969), the ‘dichotomy theory’ (Liu, 1995), a hyperactive dental lamina (Primosh, 1981; Brook, 1984) and a combination of genetic and environmental factors-unified etiologic explanation (Brook, 1984).6
Supernumerary teeth may erupt normally, remain impacted, appear inverted or assume an abnormal path of eruption. Supernumerary teeth with a normal orientation will usually erupt. However, only 13−34% of all permanent supernumerary teeth are erupted, compared with 73% of primary supernumerary teeth.7
The presence of mesiodens often results in complications like, retention of primary teeth and delayed eruption of permanent teeth, closure of the eruption path, rotations, retention root resorption, pulp necrosis, and diastema, as well as nasal eruption and formation of dentigerous and primordial cysts. Less common complications involving the permanent incisors include dilacerations of the developing roots and loss of tooth vitality. Other complications are formation of the primordial or follicular cysts with associated destruction of bone and oronasal fistulas. This type of problem is known to occur with some developmental disorders and syndromes such as Cleft lip and palate, Cleidocranial dysplasia, Gardner syndrome, Chondroectodermal dysplasia, Sturge-Weber syndrome, Down’s syndrome, Crouzon disease, oro-facial- digital syndrome, Hallerman-Streiff syndrome, and Fabry- Anderson syndrome. Management of supernumerary teeth depends on the type and position of the tooth. Immediate removal of mesiodens is usually indicated in the following situations; inhibition or delay of eruption, displacement of the adjacent tooth, interference with orthodontic appliances, presence of pathologic condition, or spontaneous eruption of the supernumerary tooth. Munns stated that the earlier the mesiodens is removed, the better the prognosis.5
Most cases of mesiodens are discovered during the first decade as this period coincides with the eruption time of maxillary central incisors and radiographic examinations are performed as an aid to screening for congenitally missing teeth, supernumerary teeth, cysts and tumors when delayed eruption or malposition of the maxillary central incisors are seen.8
Out of 4, three of our cases presented with rotation of central incisors/incisor and one case showed labial displacement of central incisor resulted due to presence of erupted/impacted mesiodens.
Severely rotated anterior teeth are difficult to treat with a removable appliance as a pure couple is required. Partially bonded appliances can be used wherein a pure couple is applied on a rotated tooth using 1st molars as anchorage along with an aligning wire in the other anterior for simultaneous correction of teeth angulations if indicated. The 2×4 or 2×2 appliance is a highly efficient system that has multiple applications in orthodontics, particularly in the initial stages of treatment. This appliance offers many advantages over alternative techniques as it provides complete control of anterior tooth position, is extremely well tolerated, requires no adjustment by the patient and allows accurate, rapid positioning of the teeth and also the force magnitude and vector can be controlled much more precisely than with a removable appliance
In practice most teeth to be rotated create two pressure sides & two tension sides. As suggested by Muthu MS, 2001, a well balanced couple i.e., an arrangement of two forces of equal magnitude & opposite parallel but non-collinear lines of action should be established to produce pure rotation. This was taken into consideration while designing the appliance so as to get a well balanced couple.9
In above documented cases, 2×4 appliance was used in 3 cases while 2×2 appliance used in one case.
The primary objective of managing orthodontic problems in the mixed dentition stage is to intercept or correct malocclusions that would otherwise be maintained or become progressively more complex in the permanent dentition or result in skeletal anomalies. Such orthodontic intervention in the mixed dentition does not always prevent orthodontic problems from occurring in the permanent dentition; however, there can be significant advantages to early intervention. By identifying and treating certain problems at an early age it is often possible either to prevent more serious orthodontic problems from developing or to redirect skeletal growth and improve the occlusal relationship.10
In above presented cases, we have restored esthetic and anterior occlusion in mixed dentition period which will not only prevent further complications but also improved self esteem of this vulnerable age group.
CONCLUSION The mesiodens is a fairly common, though usually unperturbing but interesting dental anomaly that a dental practitioner chances upon. It can be associated with the presence of other unerupted supernumerary teeth which is evident only on radiographic evaluation. One of the most common causes of severe rotation of upper incisors is the presence of supernumerary teeth. The four cases above demonstrate the versatility of the 2x4 appliance in the correction of rotation and alignment of the incisors. The treatment objectives are achieved with a short course of treatment. Further treatment may be required in the permanent dentition, but early treatment in these cases will not only quickly restore anterior aesthetics but may also reduce the complexity and duration of any subsequent treatment required.