Hypodontia of permanent teeth in Danish schoolchildren

Hypodontia, congenitally missing teeth, is one of the conditions recorded during systematic orthodontic screening of groups of children attending a community child dental health service. The present investigation reports the prevalence of hypodontia in 3325 9–10-year-old children in the 3rd schoolgrade examined with an orthopantornographic radiograph. The prevalence of children with hypodontia was found to be 7.8%. Fifty percent of these children were missing only one tooth while 85% were missing either one or two teeth. More teeth were missing in the mandible than in the maxilla. The teeth most frequently missing were the second premolars, representing 67% of the congenitally missing teeth. Symmetrical hypodontia of second premolars occurred approximately twice as often in girls as in boys. Though more teeth were congenitally missing in girls than in boys, no difference could be seen in the prevalence of hypodontia in boys (7.7%) and girls (7.8%).     

Agenesis of permanent mandibular anterior teeth: a case report

Tooth agenesis is one of the common congenital anomalies seen in humans. Hypodontia is the congenital absence of 1 or a few teeth only, with a prevalence of approximately 2% to 10% in the permanent dentition. The number of patients exhibiting congenitally missing mandibular incisors is low, with a prevalence rate of less than 1% observed. The purpose of this paper was to report a case of congenitally missing permanent mandibular incisors and canines in a 10-year-old girl.     

Erosion of the teeth: prevalence and distribution in a group of Danish school children.

AIM: This was to describe the prevalence of eroded tooth surfaces among 15-17 years old school children in a Danish city and to assess the reliability of diagnosis of erosions performed by 9 clinical examiners. METHODS: During a calendar year (2000) a total of 558 children in 4 public schools in Aarhus were examined by 7 examiners and 2 coordinators using the following criteria: intact; erosion confined to enamel; erosion exposing less than half of the dentine, and erosion involving more dentine than half the surface. RESULTS: It was found that 14.0% (95% CL: 11.3%; 17.1%) of the children had more than 3 surfaces eroded. In the maxilla lingual surfaces were more affected than the facial surfaces. No lesions exposing more than half of the dentine were observed. Despite a careful calibration, including a thorough discussion of the criteria and the experience gained during the study, a substantial inter examiner difference in diagnosis was found. CONCLUSION: The most frequently eroded sites were the lingual surfaces of maxillary incisors; the identification of eroded areas is often difficult and subject to a low inter examiner reliability.     

Traumatic injuries to anterior teeth in Italian schoolchildren: prevalence and risk factors

Abstract In the present study, the prevalence of traumatic injuries to anterior teeth in 824, 6- to I 1-year-old, schoolchildren from Rome (Italy) and the relationship between injuries and predisposing factors were evaluated. Prevalence value of the study-population was 20.26%. This value is higher than those reported in surveys performed in Italian emergency dental services, but it is similar to those of retrospective studies from other countries. The highest prevalence was found among 9-year-old boys (33.69%); the M/F ratio was 1.64. The percentage of injuries with unknown cause (21.46%) was higher than that of other studies. This may be because most of injuries were slight (64.39% of injuries were enamel fractures) and it is likely that children and their parents were not worried about them, when they happened, so that they did not seek urgent dental care - this helps to explain the prevalence values of this and other retrospective studies, which are higher than those from emergency services - and, when interviewed, they did not remember the circumstances of the traumatic event. Using the Mantcl-Haenszel's Odds Ratios stratified for age and sex, injuries were related to individual predisposing factors (overjet larger than 3 mm: OR=2.57, p = 0.0001, short upper lip: OR=2.23, p=0.0001 and upper medial incisor protrusion: OR=3.95. p = n.s.), but not to children's trauma predisposing behaviour (OR=0.92, p = n.s.). Serious injuries, however, happened lo children without predisposing factors and were caused by strong impacts, suggesting that individual risk factors may not affect these type of injuries.     

Time of permanent teeth eruption in schoolchildren of Saint-Petersburg

The terms of permanent teeth eruption were analyzed in 909 children (permanent residents of St. Petersburg) aged 7-15 years. The study showed that all groups of permanent teeth, except the first molars, erupted on the mandible earlier than on the maxilla. In girls only canines and second molars erupted earlier than in boys. There was virtually no sex-specific difference in the terms of eruption of both premolars, and the terms of the end of eruption of both groups of canines were virtually the same in boys and girls. Twenty-one children lacked some of permanent teeth by 15 years (the age considered as the upper threshold level for the end of normal tooth eruption). The most frequent teeth that failed to erupt in time were the upper lateral canines (33.3% of all teeth which failed to erupt by the age of 15 years), lower central canines and upper first premolars and molars (12.8% each).     

Prevalence of pulpally involved permanent teeth in Saudi schoolchildren

OBJECTIVE: To determine the prevalence of pulpally involved permanent teeth in children and adolescents aged 6-18 years in Saudi Arabia. METHOD: A systematic random sample was collected from the primary care files in the College of Dentistry in Riyadh. Data were collected from a total of 997 files and entered into a database and statistical program. RESULTS: A high prevalence rate of 35.8% of individuals with pulpally involved teeth was found. More extractions, pulp cappings, and root canal treatments were provided as the age increased. In all age groups molars were the most affected, and canines were the least. Maxillary incisors were affected more than mandibular incisors, while mandibular molars were affected more than maxillary molars. Females had more pulpally involved teeth than males. CONCLUSIONS: It is suggested that early oral interventions, prevention and dental education for the patients and their families may decrease this high prevalence level of pulpal involvement in teeth in this age group.     

Hypodontia and hyperdontia of permanent teeth in Hong Kong schoolchildren

This study was performed to determine the prevalence of hypodontia and hyperdontia of permanent teeth amongst Southern Chinese children in Hong Kong. The sample consisted of 1093 12-yr-old children on whom a panoramic radiograph was taken. The prevalence of congenitally missing teeth (third molars excluded) was 6.1% in boys, 7.7% in girls, and 6.9% for both sexes combined. On the average, each child was missing 1.5 teeth. The most commonly absent tooth was the mandibular incisor, affecting 58.7% of the children with hypodontia. Thirty children (2.7%) had supernumerary teeth, with a male:female ratio of 6.5:1; in four cases the tooth had erupted. Three children had fourth molars and one case of a supplemental premolar was recorded (all unerupted). Four cases of a maxillary supernumerary tooth and hypodontia in the mandible were seen.     

Dental caries prevalence in the permanent teeth in Greek schoolchildren related to age, sex, urbanization and social status

An epidemiological study of caries experience in permanent teeth of 1739 schoolchildren aged 6-17 years was conducted in Epirus, a northwestern region of Greece. Dental caries was found to be prevalent in the population examined and to increase with age. The mean DMFT values at the ages of 6, 12 and 17 years were 0.53 +/- 1.13, 4.93 +/- 4.04 and 8.88 +/- 6.19 respectively, while the average DMFT value for the total population examined was 4.96 +/- 4.83. The percentages of the children with caries-free permanent dentitions were 80 per cent at the age of 6 years, 24 per cent at 12 years and 7 per cent at 17 years. The total percentage of caries-free children was 20 per cent. Girls were found to have a higher caries prevalence than boys in all age groups. Small differences in the caries prevalence were found between rural and urban children population. Children of lower socioeconomic levels exhibited slightly higher caries prevalence than children of higher levels. The results of this baseline study indicate that dental caries is a major problem in this region of Greece and therefore an active and effective programme of dental care is necessary for the child population.     

A comparative radiographic investigation of caries prevalence in Danish schoolchildren

In order to assess the prevalence of untreated caries in two groups of Danish 7th grade (13- to 14-year-old) school children in a blind study, a radiographic investigation was carried out. Only half of the children (394) had received regular school dental care during their years of attendance of primary school; the other children (368) had not. A bitewing radiograph of the right side of the mouth of each child was taken, employing a standardized technique. The radiographs were read without the examiner knowing the group identity of the radiographs. The criteria for discarding poor radiographs, teeth, and tooth surfaces are described. Some of the radiographic results are compared with the clinical caries score of the same group. Most of the radiographs without untreated caries were found among those of the children who received school dental service. Uncertainty of method in connection with radiographic investigation is discussed.     

Agenesis of the permanent lateral incisor: distribution, number and sites

Agenesis of the lateral incisor was examined in 112 patients (42 males and 70 females). The distribution of this condition was assessed according to site, symmetry of the anomaly and the number missing for both males and females. Hypodontia of both maxillary lateral incisors was the most common form of agenesis recorded, with the absence of lateral incisors in the maxilla occurring in 91 per cent of the sample studied. Hypodontia in the maxilla was recorded more frequently in females (61 subjects) than in males (30 subjects) at a ratio of 2:1 respectively. Absence of lower lateral incisors was rare.     

Prevalence of hypodontia and developmental malformation of permanent teeth in Saudi Arabian schoolchildren

This study was carried out to determine the prevalence of hypodontia and congenital malformation in permanent teeth of Saudi Arabian male children. Five-hundred schoolchildren were investigated, selected randomly from Riyadh city. The age group of the examined sample ranged from 13 years and 6 months to 14 years and 6 months. Clinical and radiographic examinations were performed. The findings indicated that hypodontia was present in about 4 per cent of the children; most frequently affected was the mandibular second premolars, maxillary laterals, and maxillary second premolars. Tooth malformations, mainly peg-shaped upper lateral incisors were also observed in about 4 per cent of the sample.     

The prevalence and intra-oral distribution of Candida albicans in man

The prevalence of oral carriers of Candida albicans in healthy dentate adult subjects was 44.4 per cent as determined by imprint culture, 29.6 per cent by salivary samples and 13 per cent by impression cultures. Imprint cultures should therefore replace salivary samples as the method for detecting candidal carriers. Cigarette smokers had a significantly increased carrier rate (p < 0.01), compared with non-smokers. Females were more frequent carriers than males, as were subjects with lower salivary pH on the surface of the tongue, but these differences were not significant. The age, DMF index, Russell periodontal index, plaque index and intraoral temperature of subjects did not influence the carrier rate. The frequency of isolation of C. albicans and its mucosal density per unit area, as measured by imprint culture, was highest on the dorsum of the tongue, particularly the posterior half. It is concluded that Candida is not uniformly distributed throughout the mouth but that the tongue is the primary oral reservoir for the fungus, from which the rest of the oral mucosa, plaque-coated surfaces of the teeth and the saliva may become secondarily colonized in a proportion of carriers.     

西安市学龄儿童年轻恒牙外伤的现况调查

目的 探讨西安市学龄儿童年轻恒牙外伤的患病情况、分布特征及外伤原因,为卫生行政部门的决策提供科学依据。方法 采用简单随机抽样及整群抽样的方法,抽取西安市九区四县在校小学生4 013人,对学生及其家长进行问卷调查,并对有年轻恒牙外伤史的学生做口腔检查,记录外伤牙的数目与牙位。结果 西安市学龄儿童年轻恒牙外伤患病率为10.5%,各区县患病率无统计学差异（P>0.05）;儿童年轻恒牙外伤发病高峰期是7~9岁,8岁最为多见（31.5%）;最常见的牙外伤原因是跌倒（50.9%）,其次是碰撞（36.0%）;最常见的外伤牙是上颌中切牙（75.4%）。结论 西安市儿童年轻恒牙的外伤患病率处于中位水平,对处于牙外伤年龄高发阶段的儿童应该做相应的牙外伤预防措施,以降低牙外伤的发生。