Diagnosis and Management of Supernumerary (Mesiodens): A Review of the Literature
Диагностика и лечение сверхкомплектных зубов (мезиоденс). Обзор литературы
Supernumerary tooth is one of the developmental problems in children. Mesiodens is a supernumerary tooth present in the midline between the two central incisors. It usually results in oral problems such as malocclusion, food impaction, poor aesthetics, and cyst formation. The prevalence of mesiodens varies between 0.09% and 2.05% in different studies. This paper reviews current literature on etiology, prevalence, diagnosis, and management of this problem. Accordingly, early diagnosis and treatment is suggested to prevent orthodontic and pathologic complications.
By definition, supernumerary teeth are extra teeth in comparison to normal dentition. It is more common in the central region of the upper or lower jaw; however, its occurrence in the mandible is rare. The most common type of supernumerary tooth as indicated by Alberti et al. is mesiodens. Mesiodens may occur as single, multiple, unilateral or bilateral. The presence of multiple supernumerary teeth is called ‘mesiodentes’. In some syndromes, mesiodens may present as a part of the symptoms; however, this condition might be seen in normal individuals. It seems that positive family history is one of the predisposing factors.
It is important for dentists as well as anthropologists, geneticists and other health professionals to know the prevalence of dental anomalies in different communities. A few epidemiological studies have been conducted and there is considerable variation between their findings. The reported prevalence in general population ranges between 0.15% and 1.9% and it is reported to be more common in males rather than females.
Variations due to differences in demographic and environmental susceptibilities may have impact on the reported prevalence. It has been reported that in a study carried out on 9-year-old children in Italy, the prevalence of this defect has increased from 0.64 to 1.06 in recent years.
The occurrence of mesiodens in primary dentition is quite rare despite the fact that in permanent dentition it has even been considered as the most common dental abnormality. It has been reported that in 82% of the cases it occurs in the maxilla, specifically in the premaxillary region. Only a few studies have reported the occurrence of mesiodens in the anterior region of the mandible. In permanent dentition, a 0.15 to 3.8% incidence of mesiodens has been reported, with a two-fold risk of occurrence in the male population compared to the female population.
Morphologically, mesiodens may have heterogeneous forms. Three common types; namely, conical or peg shaped, tuberculate and supplemental (tooth like) have been reported, of which the conical form is the most common type.
In some subjects, mesiodens erupt normally, but usually they remain impacted or erupt in an inverted position. It is also probable that these teeth follow an abnormal path of eruption or even take an ectopic position. Ray reported erupted primary supernumerary teeth in a 4-year-old child. It seems that the erupted form is more prevalent in deciduous dentition. It is less probable for mesiodens to erupt if it occurs in multiples. In one fourth of the cases, mesiodentes do spontaneously erupt into the oral cavity. In the cases that have not erupted, they interfere with eruption of the other permanent teeth causing malocclusion.
Evidence suggests that a higher frequency of dental anomalies is more likely in some races. In primary dentition, the review of the literature by Miyoshi showed that the prevalence of supernumerary teeth in primary dentition varies between 0.05 and 0.64 in different populations. In this review, the prevalence of supernumerary teeth was reported as less as 0.05% in Japanese children to 0.64% in Canadian pupils.
The prevalence of supernumerary teeth in permanent dentition for the Caucasian general population has been reported between 0.1 and 3.8%. The estimated prevalence in the sub-Saharan Africa and Asian population is reported between 2.7 and 3.4%. The general prevalence of mesiodens in Iranian children was found 1.6% as reported by Mieghani. In this study, the prevalence of