From Volume 42, Issue 10, December 2015 | Pages 960-964
Macrodontia is a rare dental abnormality, which can cause cosmetic concerns. Various management techniques for this condition have been documented in the literature. This case describes the initial management of macrodontia in the mixed dentition stage with the use of a minimally invasive approach to treatment.
Managing dental abnormalities resulting in the alteration of tooth size and shape can present as an aesthetic and functional challenge to the dental practitioner. Macrodontia, a term used to describe teeth that are larger than would normally be expected, is characterized by an increase in the mesio-distal and facio-lingual tooth dimensions.1 The aetiology of this condition is still not fully understood, but it may be caused by a disruption to apoptosis during tooth development.2 Fortunately, macrodontia is relatively rare,3 having a prevalence of 1.1% in the permanent dentition.4
True macrodontia can be classified into three types:5
Descriptive terminology of macrodontia can be confusing, but true macrodontia of a single tooth should not be confused with gemination or fusion of two teeth (double teeth) early in odontogenesis, giving the appearance of one larger tooth.8 The term fusion is used to describe two separately developing teeth united via dentine and/or enamel.9 A review of the literature by Tuna et al reported the aetiology of this anomaly to be necrosis of intervening epithelial tissue caused by pressure between two developing teeth.10 Where fusion occurs, macrodontia will present along with one or two pulp chambers and typically there will be one less tooth in the arch,11,10 unless the fusion is between a normal and a supernumery tooth.12 Gemination can be defined as the formation of two teeth believed to arise from one dental follicle attempting to separate. In this case, there is usually only one pulp chamber and the correct number of teeth in the dental arch, if the double tooth is counted as one unit.11,10 Often present is a notch or groove on the crown.9 The prevalence of double teeth in the Caucasian population is reported at 0.1–0.2% in the permanent dentition and most frequently the anterior segments are affected.4
Macrodontia is most frequently reported to affect incisors, canines and mandibular second premolars.5,13 The incidence of macrodontia affecting the maxillary central incisor, as described in this case, is low (0.03%).14 These cases, however, can be of particular cosmetic concern to patients and can have a significant impact on their psychosocial development and interaction with peers.15 The early detection and treatment of macrodontia cases can avoid problems with aesthetics, crowding and caries, which can arise within the incisal grooves of macrodont teeth.6 Early identification and referral by the general dental practitioner (GDP) can allow for management via a multidisciplinary approach, involving input from surgical, orthodontic and restorative teams.
A healthy 7-year-old boy was referred to Liverpool Paediatric Dental Department by his GDP regarding the appearance of his recently erupted permanent maxillary central incisor teeth (Figure 1). Both the patient and his mother reported that they were unhappy with the large size and shape of his front teeth. Unfortunately, these teeth had caused the patient some distress, as he felt embarrassed by their appearance, with his mother reporting some teasing at school. Further questioning revealed the patient avoided smiling and regularly covered his mouth with his hand during talking. There was no known family history of macrodontia. His previous dental history was that of regular dental examinations in practice with no experience of any treatment. A degree of dental anxiety existed although his co-operation was good.
Clinical examination revealed a caries free mixed dentition with excellent oral hygiene (Figure 2). Both the maxillary right and left permanent central incisors were found to be macrodont, with a mesial-distal width measuring 13.5 mm and 11.5 mm, respectively. Both incisors had a groove/split in the centre of the incisal edge. Radiographically, the two large maxillary central incisors appeared to each have one pulp canal (Figure 3), and an OPG revealed that all the permanent teeth were present except the third molars and no supernumeraries were seen (Figure 4). His incisor relationship was Class I with the upper right central incisor displaced palatally in crossbite with the lower right central and lateral incisor teeth (Figure 5).
The patient was referred for an initial orthodontic opinion and, following multidisciplinary discussions, the treatment options were established as follows:
Following discussion with the patient and his family it was decided that, as a result of the patient's distress arising from his dental appearance, that treatment would be undertaken in the early mixed dentition stage. Hence, consent was gained for orthodontic approximation of the maxillary central incisors, followed by distal tooth reduction and composite reshaping. The following treatment was commenced and carried out over a five-month period:
Under six-monthly review at the Paediatric Department, the patient's dental development was found to be progressing normally, both upper canines palpable buccally and no sign of significant crowding.
He was reviewed recently on a multidisciplinary paediatric-orthodontic clinic, at the age of 11 years. At this time there was deemed to be sufficient space for all his permanent teeth to erupt. The patient underwent further minimal interproximal reduction of his upper central incisors to improve the appearance and to increase space for the eruption of his upper permanent canines, which were partially erupted. He is very happy with the appearance of his teeth and there are no plans for any further interventions.
The quoted average crown width of a central incisor is 8 mm.16 The mesial-distal widths of the two macrodont teeth in this case were 13.5 and 11.5 mm, respectively. These values are consistent with previous macrodontia cases, where widths of between 12 and 15 mm have been reported.9 Each macrodont had an incisal notch and one root canal, making the probable aetiological cause in this case gemination of the upper central incisors.
Various treatment techniques have been described in the literature for the management of macrodontia and double teeth. One review reported the main factor influencing management was the root and root canal morphology of double teeth. Hemisection was listed as the treatment of choice for teeth with two separate roots and crown modification or extraction was popular for teeth with only one canal.17
In cases of macrodontia or gemination, where there is only one root canal, often the affected tooth is extracted and the space is closed using orthodontic measures. Such treatment modality is described in a case by Hellekant et al, who managed a 9-year-old boy presenting with a Class II division 1 malocclusion and two macrodont maxillary central incisors, both with one enlarged pulp chamber.7 They considered conservatively reshaping the malformed teeth but opted for their early extraction, employing orthodontic treatment to achieve space closure and overjet/overbite reduction. Lateral incisors and canines replaced the central and lateral incisors, respectively, and the maxillary first premolars were positioned in the canine space. Restorative input disguised the shape of the laterals/canines to resemble central and lateral incisors.7 This aesthetic result was achieved over a considerable time period, and may not be indicated for all malocclusions. This case example highlights the need for early input from orthodontic colleagues in the initial treatment planning stage.
Thomas et al describe an ultra conservative technique used to treat an older 17-year-old male with macrodont central incisors and a missing upper right lateral incisor.18 Double composite veneers were constructed to disguise the large teeth and resemble a central and lateral incisor. The authors report this technique is particularly effective when a low upper lip line exists. It is indicated once dental development is complete, producing a stable gingival margin. Data has shown that increased clinical crown length continues throughout the teenage years, thus having implications for adolescent treatment planning19 and making this option inappropriate in our young case patient. This could be suited to cases of fusion, where typically there are missing lateral incisors and two macrodont centrals.
When two root canals are present in cases of dental fusion, previous management strategies have involved surgically splitting the root and associated coronal portion, termed hemisection. Subsequent pulp or root-canal therapy may be required, along with crown modification and orthodontic techniques employed to close spaces.12
Timely referral of such cases can allow development of a comprehensive treatment plan incorporating both short- and long-term goals. Early treatment in the mixed dentition stage can achieve a significant improvement in a patient's self esteem at this young age. As future complications involving impeded eruption and crowding are possible due to lack of space, close monitoring is essential to the success of such cases. Further interventions are planned, but only at the appropriate stage of dental development.
Early referral to a specialist paediatric unit is essential when dental anomalies present. As this case illustrates, to achieve success management must include both short- and long-term plans and involve input from multidisciplinary teams throughout all stages of dental development.
