The aetiology of MIH is not clear yet, and the results of this study support the results of previous studies regarding the putative causal effect of several factors.

The objective of the study was to determine the distribution, aetiology of the crown fractures of permanent anterior teeth in children aged 7-9 and 11-13 years and to identify the role of participation in sports associated with crown fractures. The study population comprised 2570 students from 10 primary schools randomly selected from five municipalities in Ankara, Turkey. Two paediatric dentists examined all permanent maxillary and mandibular incisors for evidence of fracture and completed a standardized examination form to obtain information on the age, gender, severity of incisor injury and frequency and type of sports participation for each child, as well as whether or not children used mouthguards during sports activities. Chi-square and z-tests were used to determine differences. A total of 191 (7.43%) of the 2570 subjects examined were affected by dental trauma. The proportion of fractured incisors was significantly higher in males than in females among older children (P < 0.01). Out of a total of 222 fractured teeth, 84% involved the maxillary central incisors. Bicycling caused significantly higher rates of crown fractures than other types of sports (P < 0.05). The percentage of incisal fractures caused by sports-related accidents was 14.14%. The number of children interested in sports is high, and the sports chosen are generally contact sports. The high rate (14.14%) of crown injuries caused by sports activities supports these findings.

No abstract

Supernumerary teeth occur frequently in permanent dentition, but they are rarely found in primary dentition. Supernumerary teeth of orthodox shape and size that resemble normal dentition are called ‘supplemental teeth’. Supplemental teeth are less common than supernumerary teeth and are often overlooked because of their normal shape and size.Supplemental teeth may cause esthetic problems, delayed eruption and crowding, and they require early diagnosis and treatment to prevent complications. The case reported here is one of bilateral supplemental teeth impeding the eruption of permanent maxillary lateral incisors, and it emphasizes the importance of early diagnosis and treatment during early mixed dentition.