Eruption times of the permanent teeth in 622 Ugandan children

In a survey of oral conditions carried out in Uganda in 1966, eruption times of the permanent teeth were established for 622 children. Using both the mean and the median as expressions of central tendency, it was found that girls erupted their teeth earlier than boys, with the exception that the first tooth was erupted at an earlier age in boys than in girls. Neither the fluoride content of drinking water, nor the caries prevalence, nor ritual extractions of primary teeth in the geographic regions surveyed could account for the accelerated eruption of the permanent teeth. Earlier reports that eruption of permanent teeth is accelerated in Negro as compared with Caucasoid populations was corroborated by the present study.     

Prevalence of hypodontia and malformations of permanent teeth in Iceland

This study was performed to elucidate the prevalence of hypodontia and congenital malformations of permanent teeth in Iceland. Computer analysis was done on the basis of results from examining 1,116 children (521 boys and 595 girls), or about 9.5% of all schoolchildren in Reykjavík in stages DS 3 (canines and premolars erupting) and DS 4 (canines and premolars fully erupted) of dental development at the time of the study. The age range was mainly from 8-16 years. The prevalence of congenitally missing teeth (second and third molars excluded) was 6.7% in boys and somewhat higher, 8.9%, in girls, 7.9% for both sexes combined. On the average, each child was missing 1.9 teeth. In the girls, the most commonly absent teeth were the mandibular second premolar (55%), the maxillary second premolar (19%), and the maxillary lateral incisors (18%). In the boys the figures were 51%, 18%, and 10%, respectively. Malformation of permanent teeth, mainly in the form of pegshaped maxillary laterals, was also less common in the boys, 1.3% against 3.0% in the girls, and 2.2% for both sexes combined. Among Icelandic children hypodontia and/or congenital malformation of permanent teeth were found in 9.1%.     

Anomalies of deciduous teeth and findings in permanent dentition]

Prevalence of anomalies of deciduous teeth has been analyzed in the general population of Zagreb preschool children. The sample comprised 2,987 children from 3 to 6 years of age (1,582 boys and 1,405 girls). Hypodontia was found in 0.47%, hyperdontia in 0.10%, and double teeth in 0.43% of total sample. Total prevalence of all anomalies in the sample was 1.0%. The sample for the analysis of permanent dentition has been enlarged with the clinical sample of children having the same anomalies and comprised 48 children. In all children with anomalies of primary teeth the orthopantomograms were taken and the status of permanent dentition was analyzed. In children with hypodontia in primary dentition hypodontia of permanent teeth was found in 100% of cases. Patients with hyperdontia of primary teeth displayed anomalies in permanent dentition in 85.7%, while in children with primary double teeth, anomalies of permanent teeth were present in 61.1% of cases. Missing deciduous teeth were found in both jaws in only 8.7% of cases, and in 34.8% in permanent dentition. Symmetrical occurrence of hypodontia of primary teeth (i.e. in both sides of jaws) was significantly higher in boys (56.3%) than in girls (28.6%). In permanent dentition symmetrical occurrence of hypodontia was significantly higher than in primary dentition (81.3% in boys and 57.1% in girls). The most frequently missing primary teeth were maxillary lateral incisors (48.8%) followed by mandibular central incisors (34.9%). Hyperdontia of primary teeth has been found only in boys, and it related only to the maxillary lateral incisors. Anomalies of deciduous teeth show a high degree of association with the finding in the permanent dentition.(ABSTRACT TRUNCATED AT 250 WORDS)     

Agenesis of permanent teeth in 8138 Danish schoolchildren: prevalence and intra-oral distribution according to gender

Objective.  The purpose of this study was to describe agenesis of permanent teeth in children with respect to prevalence and intra-oral distribution according to gender.
Methods and subjects.  The study was population based and included all children in one district of the municipality of Aarhus, Denmark, in 1974–1979 (1657 girls and 1668 boys) and 1992–2002 (2409 girls and 2404 boys). The children underwent systematical clinical and radiographic examination.
Results.  The period prevalence rates were almost identical for the two time periods (1972–1979: 7.8%; 1992–2002: 7.1%). Girls were affected more frequently than boys, and affected girls had more congenitally missing teeth than affected boys. Unilateral agenesis of the second premolars was more frequent than bilateral agenesis. In children with only one congenitally missing tooth, agenesis of the upper lateral incisors was asymmetrical in girls, but not in boys, whereas the opposite was true for the lower second premolars in boys.
Conclusion.  The prevalence of agenesis of permanent teeth in Danish schoolchildren seems to be constant over time, and similar to that found in other large, population-based studies. Intra-oral distributions of congenitally missing teeth indicate gender-specific patterns.     

Prevalence and distribution of anomalies of permanent dentition in 9584 Japanese high school students

This study investigated the prevalence and distribution of anomalies of permanent dentition in the current Japanese population by examining an unbiased sample. We conducted a survey of dental anomalies by mass dental screening at eight high schools in 2012. Participants were all students with permanent dentition. Dental anomalies were classified as hypodontia, supernumerary teeth, peg-shaped teeth, fused teeth, and talon cusps. Students with one or more dental anomalies on oral examination were given a differential diagnosis by three specialists. The final sample comprised 9584 participants (5062 boys, 4522 girls). Hypodontia was present in 372 students (3.88 %) with no significant sex difference (191 boys, 181 girls). Frequent sites were the right or left mandibular second premolar, right or left maxillary second premolar, and right or left maxillary lateral incisor. Supernumerary teeth were observed in three boys (0.06 %) and one girl (0.02 %). Peg-shaped teeth were observed in 74 students (0.77 %; 27 boys, 47 girls), differing significantly between sexes; they were most prevalent among maxillary lateral incisors. Of affected students, 18 students (0.19 %) also had hypodontia (3 boys, 15 girls). Fused teeth were present in two boys (0.04 %) and three girls (0.07 %) (gemination in one boy and fusion in the remaining four students). Sites were limited to maxillary and mandibular central and lateral incisors. Talon cusps were observed in two boys (0.04 %) and four girls (0.09 %). The present survey of a large unbiased sample can be considered to reflect the prevalence and distribution of anomalies of permanent dentition in the current Japanese population.     

Fractured and avulsed permanent incisors in Finnish children. A retrospective study.

The frequency of traumatic injuries to permanent incisors was studied in a sample of 1614 children from the city of Lahti in Southern Finland. The children, 801 girls and 813 boys, ranged in age from 6 to 16 years. Injuries to hard dental tissues and exarticulations of teeth were recorded. The prevalence of injuries was 19.8%--14.6% in girls and 25.0% in boys. A rapid growth in the prevalence rates was found at the ages of 9--11 years, at which the estimated mean annual incidence was about 5% in girls and 7% in boys. In 78.4% of the children with injured incisors, one tooth only was injured. The teeth most commonly injured were the upper central incisors, 81.7%; and the most frequent type of injury was an uncomplicated crown fracture, 90.5%.     

Traumatic dental injuries in a cohort of 16-year-olds in northern Sweden

Abstract The prevalence and yearly incidence of traumatic tooth injury between 1 and 16 years of age were studied in a cohort of 16 year-olds, born in 1975, and residing in the County of Västerbotten, northern Sweden. The study comprised 3007 dental records from the public denial health service. The general distribution was 50.3% girls and 49.7% boys. The records showed that 35% of the children on one or more occasions had sustained injury to their primary or permanent dentition. The frequency was nearly twice as high for boys (64%) as for girls (36%). Twenty-five percent of the 16-year-olds had met with tooth injury more than once and this group consisted predominantly of boys. The incidence of injury episodes to primary and permanent teeth was 28 per 1000 per year. The boys had sustained trauma to their teeth most frequently when they were 4 years of age and between the ages of 8 and 11. This was also true for girls at 4 and at 9 years of age, although less evidently so. In the primary dentition, the majority of dental injuries had affected the supporting tissue of the maxillary incisors. In the permanent dentition, 75% of the traumatised teeth were upper incisors. Fractures of varying severity constituted 60% of all registered diagnoses in this dentition, followed by subluxation (19%) and concussion (11%).     

Emergence of permanent teeth in Tanzanian children

OBJECTIVE: The aim of the present study was to investigate the emergence of permanent teeth among Tanzanian children. METHODS: A total of 869 Tanzanian children were recruited from 16 schools in age groups 3.5-5, 6.5-8, 9.5-11 and 15-16 years of whom 428 (49%) were boys and 441 (51%) were girls. The effects of age and gender on the emergence stages of the dentition were determined for the four age groups. RESULTS: Girls, but not boys, had some permanent maxillary canines, second premolars and mandibular and maxillary second molars as early as at the age of 6.5-8 years. Permanent teeth of both the first and the second transitional periods were already emerging at the age of 3.5-5 years and 6.5-8 years, respectively. At 3.5-5 years, 9% of the permanent teeth belonging to the first transitional period were already in occlusion. Emergence of incisors and first molars was more advanced in girls than in boys in age groups 3.5-5 and 6.5-8 years. CONCLUSIONS: Parallel to earlier reports on different ethnic groups, the results of this study indicate that the permanent teeth of Tanzanian children erupt earlier in girls than in boys, and the mandibular teeth erupt earlier than the corresponding maxillary teeth. The difference between boys and girls was found in both the first and second transitional period. Permanent teeth in Tanzanian children clearly emerge earlier than in Caucasian children.     

Hypodontia in children with various types of clefts

The prevalence of hypodontia in children with clefts, both inside and outside the cleft region, and the possible association between the side of the cleft and the side of the missing teeth were studied using radiographs of 278 patients with cleft lip, cleft palate, or both (158 boys and 120 girls), age 5 to 18 years (mean age 10.4 years). A hypodontia prevalence of 77% (excluding third molars) was found for the total cleft sample. This was significantly higher, both statistically and clinically, than the incidence of hypodontia reported for noncleft populations, and considerably higher than the prevalence reported in other studies of children with clefts. The maxillary permanent lateral incisors were the teeth most frequently missing on the cleft side (259 teeth) followed by the maxillary (47 teeth) and mandibular (23 teeth) second premolars, in both boys and girls. The teeth that were most often missing on the noncleft side were the maxillary second premolars (12 teeth), followed by the maxillary lateral incisors (10 teeth) and mandibular second premolars (6 teeth). Hypodontia of both the maxillary lateral incisors and second premolars was found more frequently on the left side, which also has a higher frequency of clefting.     

Sexual dimorphism of primary dentition in Spanish children

Aim: To analyse differences in the eruption of primary teeth between both sexes.

Materials and methods: A cross-sectional study was performed in a sample of 1250 children aged between 3 and 42 months. The clinical emergence of teeth was taken to estimate average ages for primary teeth eruption. The t-test was used to analyse gender and arch differences.

Results: Eruption of primary teeth began at the same time in girls as in boys; although the eruptive process was longer in girls. It was observed that almost all deciduous teeth emerged earlier in boys, except for the first molar (upper and lower) and the maxillary central incisors. The differences were statistically significant for almost all the primary teeth except for the central incisors, both upper and lower.

Conclusions: By comparing the timing of the eruption of primary teeth in both sexes, it was found that eruption of almost all primary teeth took place earlier in boys than in girls and that the eruption process was shorter for boys than for girls. Most of the deciduous teeth erupted earlier in the right side in both sexes. No differences were found in the sequence of eruption of primary teeth between genders.     

Variations in number and morphology of permanent teeth in 7-year-old Swedish children

Summary. Objectives . To establish the prevalence of numerical and morphological variations of permanent teeth in Swedish 7-year-olds and to accept or reject the hypothesis of a higher prevalence for these conditions in northern Sweden compared to other areas.
Design . Cross-sectional.
Setting . Department of Odontology/Pedodontics, Umeå University, Sweden.
Sample and methods . A total of 739 healthy Caucasian 7-year-olds residing in the city of Umeå, northern Sweden in 1976. The children were examined clinically and radiographically.
Results . The prevalence of hypodontia (excluding third molars) in girls was 8·4%, in boys 6·5%, and in both sexes combined 7·4%. Of the children with hypodontia, the majority (90·9%) lacked one or two teeth. Lower second premolars were the teeth most frequently missing. The prevalence of hyperdontia was 1·9%; 11 girls and three boys were affected; 78% of the supernumerary teeth were mesiodenses. Of the morphological variations, peg-shaped upper lateral incisors were found in 0·8% of the children, double-formation (gemination) in 0·3%, taurodontism in 0·3% and dens invaginatus in 6·8%. One diagnosis was found in 18% of the children, and in almost 8% of them more than one diagnosis was found.
Conclusions . The results agree with those obtained in similar populations and are considered representative of this ethnic group. The hypothesis of a genetically determined higher prevalence of numerical and morphological variations in the study population was not verified.     

Mesiodens: a radiographic study in children

We analyzed the frequency and radiological features of mesiodens in a group of children in Turkey. The study was based on a radiographic review of 23,000 pediatric patients (male: 12,667 female; 10,333) who visited the Department of Oral Diagnosis and Radiology during the period 2003-2005 (3 years). The presence of an unerupted supernumerary tooth, or tooth bud between the 2 central incisors or as unilateral or bilateral teeth in the midline of the maxilla was noted as mesiodens on radiographs. Eighty-five cases of mesiodens in 69 patients were found. Complete documentation, including radiographs, for these 69 patients were studied and analyzed. In addition to gender and age, the following information about the mesiodens was recorded: 1) number; 2) shape; 3) position; 4) complications caused by the mesiodens; 5) treatment. Of the 69 patients, the ratio of boys (47 cases) to girls (22 cases) was 2.1:1. Fifty-three (76.8%) of the children had 1 mesiodens, and 16 (23.1%) had 2 mesiodentes bilaterally to the midline. Of the 85 mesiodentes, 67 (78.8%) were fully impacted, 6 (7%) were partially erupted, and 12 (14.1%) were fully erupted. Most of the mesiodentes (55.2%) were found in the vertical position, followed by inverted position (37.6%), and horizontal position (7%). The main complications were delayed eruption of the permanent incisors (38.8%), maxillary midline diastema (17.6%), axial rotation or inclination of erupted permanent incisors (16.4%), and resorption of the adjacent teeth (4.7%) The prevelance of mesiodens has been estimated to be 0.15% to 2.2% of the population.     

Traumatic injuries to upper permanent incisors related to age and incisal overjet. A retrospective study.

The relationship between traumatic injuries to upper permanent incisors and incisal overjet, with special reference to the age at which the trauma occurred, was studied in a sample of 1437 orthodontically untreated children aged 7--16 years. Traumatic injuries to hard dental tissues and exarticulations of teeth were recorded. Before 10 years of age, the increase of the prevalence rates was most rapid in the extreme (greater than 6 mm) overjet group in both sexes; the ratios between the extreme and normal (0--3 mm) overjet groups being 6.5/1 in girls and 5.0/1 in boys. According to the estimate, about 50% of the girls and 70% of the boys in this overjet group with injuries were affected before the age of 10 years.     

Prevalence of traumatized permanent incisors in Jordanian children, according to age, sex and socio-economic class.

The purpose of this retrospective study was to analyse firstly the prevalence of firsty fractured permanent incisors, secondly their distribution according to age, sex and socio-economic class and thirdly the location of the trauma, in a population sample of schoolchildren from Jordan. The sample consisted of 3041 children aged 7-12 years enrolled in 6 public and private schools from the city of Amman and its outskirts. The prevalence of fractured permanent incisors was 10.5% (12.1% in boys and 8.8% in girls). The largest number of injuries was observed in the 11-12 years group (15.0%) and there was an increase of the prevalence of trauma associated with the increase of age. Significantly more boys suffered injuries than girls (P less than 0.01). The teeth most commonly injured were the maxillary central incisors (79.1%) and 85.2% of children sustained one fractured tooth only. The numbers of traumatized children in each of the low and middle socio-economic classes were significantly higher than those in the high socio-economic class.     

Eruption time of primary teeth in Iraqi children

Abstract The mean times and order of eruption of primary teeth were determined cross-sectionally from 1017 Iraqi nursery schoolchildren, ranging in age from 1 to 40 months. No statistical differences were found in the mean ages of eruption between corresponding right and left primary teeth in both sexes. The order of eruption for the maxilla and the mandible was the same in both sexes. In boys teeth erupted earlier than girls except for the maxillary central incisors and the mandible second molars.     

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).     

Traumatic dental injuries in a sample of Dominican schoolchildren

Abstract The purpose of this retrospective study was to analyze 1) the prevalence of traumatic injuries to permanent incisors and canines, 2) their distribution according to type, 3) etiology, 4) place of occurrence, and 5) location of trauma, in a population sample of schoolchildren from the Dominican Republic, located in the Caribbean Archipelago. The sample consisted of 596 children aged 7–14 years enrolled in 21 public and private schools from the city of San Pedro de Macoris, in the southeastern part of the country. This sample represents 10.8% of the schoolchildren of the city. The prevalence of injuries was 18.1 % (17.4% in boys and 18.8% in girls). The largest number of injuries was found in the 14-year-old children followed by the 12-year-olds. Significantly, girls had a larger number of actual teeth injured than boys (P < 0.05). The most common type of injury in both sexes was the enamel fracture (51.1%) followed by concussions (25.6%). Significantly, more girls suffered concussions than boys (P < 0.05). The most common cause of injury in both sexes was falling against an object (60.0% in boys and 42.6% in girls). The most frequent place of occurrence of trauma, in both sexes, was at home (34.1 %), followed by outside of home (19.3%) and at school (12.5%). The teeth most commonly injured were the maxillary central incisors (63.9%). Girls presented significantly more mandibular lateral incisors injured than boys (P < 0.02).     

An orthopantomographic study of hypodontia in permanent teeth of Japanese pediatric patients

Hypodontia of permanent teeth was evaluated from orthopantomograms of 2072 apparently healthy pediatric patients at The Hospital of Nihon University School of Dentistry at Matsudo. The prevalence of congenitally missing teeth (CMT) was 8.7% in boys and 10.8% in girls, and 9.4% for both sexes combined. Most cases (67.8%) involved either one or two missing teeth. There were in total 574 CMT, and on average 2.8 teeth were missing per child. The most commonly absent tooth was the mandibular second premolar. On the other hand, no first molars were missing in any case. A high frequency of CMT mandibular incisors (18.82%) was observed, and this seems to be a characteristic peculiar to individuals of Asian ethnicity. Oligodontia (6 or more CMT excluding the third molar) ranged from 6 to 14 teeth, with a prevalence of 1.4% in general: 1.8% for girls and 0.9% for boys. Symmetry of CMT was predominant: 214 pairs for bilateral symmetry and 107 pairs for symmetry between two antagonistic quadrants. The distribution of CMT between maxillary and mandibular hypodontia in the right and left quadrants for boys and girls no had significant association (P < 0.05).     

A survey of hypodontia in Japanese orthodontic patients.

INTRODUCTION: The purpose of this retrospective study was to assess the prevalence and distribution of hypodontia in the permanent dentition, excluding the third molars, in a sample of Japanese orthodontic patients. METHODS: Orthopantomograms of 3358 Japanese orthodontic patients (1453 boys and 1905 girls) between the ages of 5 and 15 years were examined for evidence of hypodontia. RESULTS: The prevalence of hypodontia was 8.5% (7.5% for boys, 9.3% for girls) with no statistically significant difference between the sexes. The average number of missing teeth per child was 2.4 (2.5 for boys, 2.4 for girls). Most (76.3%) children with hypodontia were missing either 1 or 2 teeth (77.1% for boys, 75.7% for girls). The prevalence of advanced hypodontia was 10.1% (11.0% for boys, 9.7% for girls). The most commonly missing teeth were the mandibular second premolars, followed by the mandibular and maxillary lateral incisors, and the maxillary second premolars; minor differences in the order of prevalence existed among groups of children classified by the number of missing teeth. Symmetrical hypodontia was predominant, and the most commonly symmetrical hypodontia was mandibular second premolar agenesis. No consistent finding was obtained as to which jaw had more missing teeth. The distribution of missing teeth was similar between the right and left sides of the dental arches in each group of children. Anterior tooth agenesis was predominant in children with minor hypodontia, and posterior tooth agenesis increased with hypodontia severity. CONCLUSIONS: The distinct characteristic of hypodontia in the Japanese population compared with other populations was a higher prevalence of both advanced hypodontia and mandibular lateral incisor agenesis in children with minor hypodontia.     

Labial-cervical-vertical groove in maxillary permanent incisors--prevalence, severity, and affected soft tissue.

OBJECTIVES: To investigate the prevalence and severity of a labial-cervical-vertical groove (LCVG) in maxillary permanent incisors and its effect on the associated gingival tissue. METHODS: A total of 600 adolescents (293 boys and 307 girls, mean age 13.6+/-1.99 years) were randomly selected and examined for the presence of LCVG. The deformity was classified as mild, moderate, or severe according to predetermined criteria. Gingival coverage at the groove site was defined as normal, partial, and irregular. RESULTS: LCVG was found in 27 adolescents (4.5%). It was unilateral in 24 (89%) and bilateral in 3 (11%). The ratio of central to lateral incisors was 29:1. No sexual dimorphism or side prevalence were found. Mild LCVG was found in 22 incisors, moderate LCVG in 7 incisors, and severe LCVG in one incisor. Moderate LCVG was 5 to 6 times more susceptible to partial or irregular coverage of the gingival margin than mild LCVG. The gingival sulcus in teeth with LCVG demonstrated a significant (P = .001) increase in depth compared to non-LCVG teeth (1.55+/-0.90 mm vs 1.18+/-0.75 mm). CONCLUSIONS: An LCVG is a deformity confined predominantly to a single permanent maxillary central incisor. Its prevalence is not connected with gender. Most LCVGs are mild and often difficult to detect. However, the greater the severity, the more gingival irregularity is associated. This and the increase in sulcus depth in LCVG incisors are adverse predispositions for periodontal sequelae, calling for cautious oral hygiene maintenance.