Analysis of congenital deciduous teeth absence and its permanent teeth phenotype / 华西口腔医学杂志

OBJECTIVES@#This study aimed to investigate the clinical characteristics of congenital deciduous teeth absence and its permanent teeth performance type by using panoramic radiographs.@*METHODS@#A total of 15 749 panora-mic radiographs of 3-6-year-old children with deciduous dentition were collected from January 2020 to December 2021. The incidence of congenital deciduous teeth absence was observed, and the abnormality of permanent teeth was recor-ded. SPSS 24.0 software was used for statistical analysis.@*RESULTS@#The incidence of congenital deciduous teeth absence was 2.54% (400/15 749), which was found in 217 girls and 183 boys, and the difference between the genders was statistically significant (P=0.003). The absence of one and two deciduous teeth accounted for 99.75% (399/400) of the subjects. In addition, 92.63% (490/529) of mandibular deciduous lateral incisor was congenitally absent, 44.80% (237/529) of deciduous teeth was absent in the left jaw, and less than 55.20% (292/529) was absent in the right; the difference between them was statistically significant (P=0.017). The absence of 96.41% (510/529) deciduous teeth in the mandibular was significantly more than that of 3.59% (19/529) in the maxillary, and the difference between was statistically significant (P=0.000). Furthermore, 68.00% (272/400) and 32.00% (128/400) of deciduous teeth were absent in unilateral and bilateral, respectively, and the difference was statistically significant (P=0.000). Four types of congenital deciduous teeth absence with permanent teeth were observed as follows: 1) 73.91% (391/529) of permanent teeth was absent; 2) 20.60% (109/529) of permanent teeth was not absent; 3) the number of fused permanent teeth accounted for 4.91% (26/529); 4) the number of supernumerary teeth was 0.57% (3/529).@*CONCLUSIONS@#Although the absence of congenital deciduous teeth is less common than that of permanent teeth, it affects deciduous and permanent teeth to some extent. Dentists should pay attention to trace and observe whether abnormalities are present in the permanent teeth and take timely measures to maintain children's oral health.

Fusión del tercer molar inferior con un cuarto molar: reporte de tres casos / Fusion of the lower third molar with a fourth molar: report of three cases

Los dientes supernumerarios y la fusión dental son anomalías del desarrollo dental cuyas causas aún no se han dilucidado con certeza. El cuarto molar inferior, también denominado distomolar, es uno de los dientes supernumerarios con menor frecuencia de aparición clínica y su fusión con el tercer molar es una condición todavía menos común. A continuación, se reportan los casos clínicos de tres pacientes masculinos que presentaron fusión del tercer molar inferior derecho con un distomolar tratados mediante odontectomía (AU)

Supernumerary teeth and dental fusion are abnormalities of dental development whose causes have not yet been elucidated with certainty. The lower fourth molar, also called distomolar, is one of the supernumerary teeth with the least frequency of clinical appearance and its fusion with the third molar is an even less common condition. Next, the clinical cases of three male patients who presented fusion of the right lower third molar with a distomolar treated by odontectomy are reported (AU)

[ occurrence of anomalies of primary anterior teeth and their concurrence with the permanent successors anomalies in Iranian children]

Numerous studies report the prevalence of tooth absence, extra tooth, and double tooth [fusion and germination] in anterior primary teeth as being just less than 1%. Due to low prevalence of such anomalies, little attention is paid to them. There are concrete effects on corresponding permanent teeth and developing occlusion in about 50% of these cases. The aim of the present study was to determine the frequency of such problems in 113 cases, and to discuss the effect of these anomalies on the permanent successors. A total of 113 cases of the different 4 types of anomalies [39 cases of fusion, 14 cases of germination, 39 cases of missing, and 21 cases of supernumerary teeth] were studied. The cases were among the patients referring to the author's private clinic during the past 20 years for whom an appropriate radiography had been performed. The cases with tooth absence due to extraction or trauma were excluded. The results of the study were descriptively analyzed and reported. In the present study, the distribution of the anomalies including 39 cases of fusion, 14 cases of germination, 39 cases of issuing, and 21 cases of supernumerary teeth based on sex, maxillary and mandibular arches, tooth type, being unilateral or bilateral, as well as the impact of each on the succeeding permanent teeth were reported. The results show that the highest prevalence of fusions was seen in the central and lateral mandibular teeth, while there was a good balance for the missing tooth in both arches. In almost 50% of the cases, the presence of fusion in primary teeth was accompanied with a missing of permanent tooth, yet in germination, the number of permanent teeth was normal. Finally, in almost half of the cases with supernumerary tooth, there was supernumerary tooth in permanent dentition. The results in this study is valuable indicating that tooth radiograph is helpful in evaluating the number of anterior permanent teeth in case such anomalies exist; Thereby, suitable treatment plans for the future could be established