Prevalence of hypodontia in Chinese orthodontic patients

A Radiographic Study of Non-Syndromic Congenitally Missing Teeth in Permanent Dentition of Nigerian Dental Patients

“…In the present study, the least affected teeth were maxillary central incisor, mandibular canines, and maxillary and mandibular first and second permanent molars (Figure 1). While some studies reported that the mandibular second premolars were most commonly missing teeth [15,20,28,30,31], others showed that maxillary lateral incisor was the most prevalence missing tooth in individuals with agenesis of only one or two teeth [7,10,14,21,22]. The most affected teeth in this study were maxillary lateral incisors, followed by maxillary and mandibular third molars, and mandibular second premolars.…”

“…It is however higher than previously reported range of 0 -3.6% in Nigerians [24][25][26]. Also, several reports from different racial populations reported prevalence of CMT ranging from 2.7% to 4.19% [13,14,16,20,21]. These differences could be due to variation in sampling techniques, methods of examination, as well as sex, age distribution and racial origin of the different sample populations.…”

“…Usually at the age of 8 to 10 years the first sign of the third molar appeared on the radiograph, but occasionally on older age. Therefore, the diagnosis of congenitally missing tooth in permanent dentition should be made after the age of 6 years if third molars were excluded, and by 10 years of age if third molars were also studied [20]. The youngest patient in this study was 10 years of age (Table 1), therefore all the patients were suitable as sample in this study according to age.…”

“…Tooth buds showing late onset of mineralization could lead to a false positive diagnosis of agenesis on radiographs [2]. Therefore, diagnosis of tooth agenesis should be made after the age of 6 years, if third molar is excluded, and after 10 years af age if the third molar is also studied [15,20]. On the basis of this criterion, the age of inclusion in this study was set at 10 years.…”

“…Many authors reported that the most frequently CMT after the third molar was mandibular second premolars, followed by maxillary second premolars or maxillary lateral incisors [15,20]. There were however, contrary reports which showed maxillary lateral incisors [7,10,14,21,22], mandibular incisors [9], and mandibular lateral incisors [23] as the most frequent congenitally missing teeth in their respective studies.…”