Congenital absence of maxillary permanent canines is an extremely rare condition, which may appear as part of a syndrome or as a nonsyndromic form. Nonsyndromic canine agenesis combined with other types of tooth agenesis has occasionally been described in the literature but isolated cases are rarely observed. This report presents an isolated case of maxillary permanent canine agenesis in a healthy 18-year-old female patient and a literature review on the prevalence, etiology, and differential diagnosis of the condition.
Tooth agenesis or hypodontia is one of the most common anomalies of the human dentition, which is characterized by the developmental absence of one or more teeth. The condition can occur in association with a recognized genetic syndrome or as a solitary anomaly (nonsyndromic). Lack of one or a few permanent teeth without any systemic disorder is the most common phenotype of hypodontia [
Both environmental and genetic factors can cause the failure of tooth development although in the majority of the cases hypodontia has a genetic basis [
Recent reports have shown that, in the Caucasian population, the prevalence of hypodontia in permanent dentition (third molar excluded) is about 4.5–7.4% [
In syndromic oligodontia, the permanent canines are often reported as missing though being with a low frequency [
This case report presents a unilateral maxillary permanent canine agenesis. A literature review on the prevalence, etiology, and diagnosis of the condition was also carried out.
An 18-year-old female patient presented to the Department of Dentomaxillofacial Radiology, Hacettepe University, for a routine dental examination in October 2013. She was in good health with no history of systemic disease or syndrome. Intraoral examination revealed a class I molar relationship with a centered dental midline and increased anterior overbite. A diastema of 2 mm between 22 and 23 was observed. Clinical examination of the maxillary teeth revealed a small canine showing signs of attrition on the right side with no mobility (Figure
Intraoral view of the maxillary arch showing the small canine on the right side with signs of attrition.
A panoramic radiograph was taken to detect the presence and the location of the permanent canine and to check for any other anomalies. The radiograph showed that the right permanent canine was missing and the erupted canine was deciduous with its small root, short crown size, and thin enamel structure. The deciduous canine was persisting with root resorption grade 1 [
Panoramic radiograph showing the absences of right permanent maxillary canine and all third molars. The deciduous canine is persisting with external root resorption. Note the radiopaque lesion in the left mandibular third molar region.
Periapical radiograph of the left mandibular molar region, showing the osteosclerotic area.
The patient was referred to the Department of Restorative Dentistry for the restoration of the decayed tooth.
Many studies have researched developmental disorders and explained these by using anatomic and evolutionary models. According to Bolk’s [
The cause of congenital absence of the teeth is variable. Severe hypodontia is usually associated with genetic disorders such as Witkop syndrome, ectodermal dysplasia, and Rieger syndrome [
The etiology of tooth agenesis has generated much debate. Graber [
The developmental absence of permanent canines is reported to be higher in women and mostly maxilla affected with the left side [
It was previously reported that single canine agenesis is more predominant than multiple canine agenesis and mostly occurs with other types of dental anomalies such as congenital absence of other teeth, microdontia, delayed tooth formation and eruption of permanent teeth, supernumerary teeth, odontoma, taurodontism, and talon cusps [
There are other possibilities that should be considered in such cases when permanent canines are clinically found to be absent. If the permanent canine could not be palpated in the buccal sulcus by eleven years of age, ectopic eruption and impaction of the teeth must be considered [
Congenitally missing maxillary canines require a specific treatment plan. Many factors should be considered: the condition of the deciduous teeth, the patient’s occlusion (crowding versus spacing and midline deviations of the arch), facial growth pattern, and the preferences of the patient. Treatment options may include the extraction of primary teeth to facilitate spontaneous or orthodontic space closure or retaining the deciduous teeth until the end of growth in order to preserve the alveolar bone quality to provide maximum potential for implant replacement without the need of bone grafting.
In the present case the main aim was to keep the primary canine as far as possible. It was decided to follow up the patient; as the root resorption of the deciduous canine had already begun, referral to a prosthodontist will be needed in the near future.
The authors declare that there is no conflict of interests regarding the publishing of this paper.