Numerical aberrations in the permanent teeth of grade school children in Jerusalem

Association between Hypodontia and Angle’s Malocclusions among Orthodontic Patients in Kathmandu, Nepal

Background. Disturbances during the early tooth development stages may result in the congenital absence of teeth. The purpose of this study was to assess the relationship between hypodontia and Angle’s malocclusions. Materials and Methods. The sample comprised 601 orthodontic patients’ pretreatment records (242 men and 259 women), selected from the achieved orthodontic records. Developmental anomalies of teeth affecting the number were examined on dental panoramic radiographs. Based on Angle’s classification, pretreatment dental casts were assessed and classified into different classes of malocclusion. The relationship between hypodontia and different classes of malocclusion was evaluated using the chi-square test. Results. The prevalence of tooth agenesis was 7.48%, that is, 45 out of 601 samples. There were a total of 72 (0.42%) missing teeth, excluding the third molars. The most frequent missing tooth was the maxillary lateral incisor (35, 48.61%), followed by the mandibular lateral incisor (14, 19.44%), the mandibular central incisor (6, 8.33%), the mandibular second premolar (5, 6.294%), and the maxillary second premolar (4, 5.55%). Hypodontia was more common in the upper jaw. Although hypodontia was mostly seen in Class I malocclusion patients (7.87%), followed by Class II malocclusion patients (6.99%) and least in Class III malocclusion patients. However, there was no significant difference in hypodontia among different classes of malocclusions (p = 0.352). Conclusion. The most frequently missing tooth was the maxillary lateral incisor, followed by lateral and central mandibular incisors and mandibular second premolars, while excluding the third molars. The present study did not find any association between various types of malocclusions and hypodontia.

Association of tooth agenesis with dental anomalies in young subjects

AIM

The aim of the current study is to correlate the presence of tooth agenesis with other dental anomalies in 7- to 15-year-old patients.

MATERIALS AND METHODS

After evaluating 4000 panoramic radiographs of young subjects, 430 revealed the presence of tooth agenesis, except for the third molar, and are retrospectively observed and compared with a non-agenesis control group of 500 subjects, in order to investigate the existence of other associated dental anomalies in both groups.

RESULTS

The prevalence of tooth agenesis was approximately 9.30% (430/4000); no significant gender differences were found. A significantly higher prevalence of microdontia of the maxillary lateral incisors (p < 0.001) and delayed tooth development (p = 0.0001) was observed in the agenesis group (group A), while delayed development of permanent teeth (p < 0.0001) and hypo-occlusion of the primary molars (p = 0.0130) were found in the control group (group B).

CONCLUSIONS

Agenesis patients presented a significantly higher prevalence of microdontia of the maxillary lateral incisors. Instead, non-agenesis patients presented a high prevalence of delayed permanent tooth development and hypo-occlusion of the primary molars. Moreover, further researches are needed to elucidate the role of genetics and environmental factors in the current sample group.

Agenesis of all permanent maxillary incisors: A rare clinical case with an interdisciplinary solution

Background

Clinical cases involving agenesis of all four maxillary incisors are rare, with no previous reports in the literature.

Case report

The present case report describes an orthodontic treatment combined with esthetic dentistry in a 10-year-old girl with agenesis of all four permanent maxillary incisors, anterior crossbite, permanence of deciduous maxillary canines and transmigration of permanent maxillary canines into the region of the maxillary central incisors. For this case, it was decided on space closure using a fixed orthodontic apparatus and reshaping of the first premolars transforming them into canines. Porcelain veneers were used on the permanent and deciduous canines, substituting the maxillary central and lateral incisors, respectively. Regarding outcome, there was an improvement in facial profile, correction of the anterior crossbite, satisfactory intercuspidation of the teeth and significant esthetic improvement in smile. Maintaining the patient´s natural dentition also kept the bone plate intact for future placement of implants to substitute maxillary deciduous canines at the appropriate age.

Conclusions

Interdisciplinary planning combining orthodontics and esthetic dentistry was key in resolving this case. Key words:Tooth agenesis, upper incisors, orthodontic treatment.

Prevalence and Characteristics of Congenitally Missing Permanent Teeth among Orthodontic Patients in Southern Croatia

BACKGROUND

Congenitally missing permanent teeth (CMPT) was recognized as a clinical and public health problem in pediatric dentistry.

AIM

To determine the prevalence of CMPT among orthodontic patients in Southern Croatia.

MATERIALS AND METHODS

In a retrospective study, we analyzed CMPT in patients from three different regions in Southern Croatia (SC). Two orthodontic practices from each region were selected and a total of 4649 records of patients aged 6 - 15 years, who were clinically examined for orthodontic treatment between 2008 and 2015, were evaluated. We excluded 219 patients and 4430 patients remained for further analysis.

RESULTS

There was no difference in prevalence of CMPT among regions in Southern Croatia, and the whole sample was evaluated. CMPT was found in 345(7.8%) patients. The highest proportion of CMPT was with one or two missing teeth 122 (81.9%) and 158 (80.6%), followed by those with three to five missing teeth or moderate hypodontia, 25(16.8%) and 35(17.9%), in males, and females respectively. Bilateral hypodontia of the lower second premolars and upper second incisors was more common than unilateral hypodontia.

CONCLUSIONS

The obtained results of high prevalence of CMPT in Southern Croatia reinforce the need for a timely diagnostics and treatment of moderate and severe cases.

Agenesis of Third Molars among Turkish Children between the Ages of 12 and 18 Years: A Retrospective Radiographic Study

PURPOSE

The aim of this study was to investigate the agenesis of third molars (M3) in children with permanent dentition in a limited population in the province of Izmir, Turkey.

STUDY DESIGN

The panoramic radiographs of 773 patients (457 females, 316 males) were evaluated retrospectively at the Dental Hospital of Ministry of Health in İzmir, Turkey. The patients' ages ranged from 12-18 years. The agenesis of M3 teeth was investigated according to maxilla and mandible and right and left distribution.

RESULTS

In 593 of the patients (76.7%), all of the M3 teeth were present in the mouth; while in the other 180 (23.3%) patients, agenesis of a varying number of M3 teeth was identified. In 31 patients (4.0%), total M3 tooth agenesis was observed. A statistically significant relationship was not found between gender and M3 teeth (p=0.091). A statistically significant relationship was found between congenital M3 tooth agenesis and the maxilla (14.3%) and mandible (9.6%) (p<0.001). However, a statistically significant difference was not found between the right-left area of the jaw (p=0.100).

CONCLUSION

As a result, while all M3 teeth were present in 76.71% of the population studied in the province of Izmir, agenesis of one or more than one M3 tooth was found in the other 23.29% of the patients studied.

The prevalence and distribution of hypodontia in a sample of Qatari patients

OBJECTIVE

The aims of this study were to determine the prevalence of hypodontia in the permanent dentition in a sample of Qatari patients attending a dental center and to compare the results with the reported findings of other populations.

MATERIALS AND METHODS

Orthodontic files including orthopantomographs of 1000 patients (655 females and 345 males, 11-36-year-old) were examined and inspected for evidence of hypodontia.

RESULTS

The prevalence of hypodontia in the present Qatari sample was 7.8%; 6.9% was in males and 8.2% in females. Hypodontia was found more frequently in the maxilla than in the mandible. The distribution of missing teeth was noticed in the left side more than the right side. The most frequently missing teeth were the maxillary lateral incisors followed by the mandibular second premolars, maxillary second premolars, and mandibular left lateral incisor. The majority of patients with hypodontia had one or two teeth missing, but rarely more than four teeth were missing in the same patient. Bilateral missing teeth in the current study was commonly seen in the maxillary lateral incisor (14.1%) followed by mandibular second premolar (12.8%) and maxillary second premolar (6.4%).

CONCLUSIONS

The prevalence of hypodontia in a sample of Qatari individuals was within the range reported in the literature for other populations. The incidence of hypodontia in the anterior segment requires multidisciplinary team approach (orthodontic and prosthodontic) to restore the esthetic and function and improve patient self-esteem.

Prevalence of hypodontia and associated factors: a systematic review and meta-analysis

OBJECTIVES

To determine the prevalence and factors associated with hypotonia.

DESIGN

Systematic review and meta-analysis.

DATA SOURCE

A search strategy was developed along with inclusion criteria and run in MEDLINE and EMBASE (published from 2002 to August 2012) databases to reveal all studies on the prevalence of hypodontia or associated factors. A hand search of reference lists and a Google search aimed to improve the sensitivity of the literature search.

SELECTION CRITERIA

All studies on the prevalence of hypodontia or associated factors published from 2002 onwards were included. Abstracts of non-English papers were also analyzed.

DATA SELECTION AND EXTRACTION

All potential articles were checked against the inclusion criteria independently, and in duplicate by two investigators. A checklist was used to assess the quality of selected studies.

MAIN OUTCOME

Prevalence of hypodontia, excluding third molars.

RESULTS

The overall prevalence of hypodontia was found to be 6.4% (95% CI: 5.7, 7.2). There was a statistically significant difference in the prevalence of hypodontia by continent (Q = 34.18, P<0.001). Prevalence of hypodontia was the highest in Africa: 13.4% (95% CI: 9.7, 18.0), followed by Europe (7% CI: 6.0-8.0%), Asia (6.3% CI: 4.4, 9.1) and Australia (6.3% CI: 5.3, 7.4) with a lower prevalence in North America (5.0% CI: 4.1-5.9) and Latin America and Caribbean (4.4% CI: 3.2-6.1). Females were found to have a higher prevalence than males (combined OR 1.22; 95% CI: 1.14, 1.30). The most commonly affected teeth were mandibular second premolars followed by maxillary lateral incisors and maxillary second premolars. The prevalence of mild, moderate and severe hypodontia was found to be 81.6, 14.3 and 3.1% respectively.

CONCLUSIONS

There was a high variation in the prevalence of hypodontia between the studies. African populations were found to have a higher risk for tooth agenesis and there was an increased risk for females to have hypodontia than males.

Congenitally missing teeth (hypodontia): A review of the literature concerning the etiology, prevalence, risk factors, patterns and treatment

Congenitally missing teeth (CMT), or as usually called hypodontia, is a highly prevalent and costly dental anomaly. Besides an unfavorable appearance, patients with missing teeth may suffer from malocclusion, periodontal damage, insufficient alveolar bone growth, reduced chewing ability, inarticulate pronunciation and other problems. Treatment might be usually expensive and multidisciplinary. This highly frequent and yet expensive anomaly is of interest to numerous clinical, basic science and public health fields such as orthodontics, pediatric dentistry, prosthodontics, periodontics, maxillofacial surgery, anatomy, anthropology and even the insurance industry. This essay reviews the findings on the etiology, prevalence, risk factors, occurrence patterns, skeletal changes and treatments of congenitally missing teeth. It seems that CMT usually appears in females and in the permanent dentition. It is not conclusive whether it tends to occur more in the maxilla or mandible and also in the anterior versus posterior segments. It can accompany various complications and should be attended by expert teams as soon as possible.

Evaluation of tooth number anomalies in a subpopulation of the North-East of Turkey

Objective:

The aim was to evaluate the prevalence and distribution of tooth number anomalies in a Turkish subpopulation.

Materials and Methods:

A population of 2722 patients (1532 females and 1190 males; mean age, 12.33 ± 2.5 years) was retrospectively examined to determine the prevalence and distribution of the hypodontia, oligodontia, and hyperdontia using panoramic radiographs. All permanent teeth were investigated except thirds molars and the data obtained were recorded as unilateral (left or right) or bilateral according to gender. Pearson's Chi-squared and Fisher exact tests were used for difference comparisons (P < 0.05).

Results:

Permanent tooth anomalies were found in at least 132 (4.84%) of 2722 patients with no statistically difference between the genders, consists of 4.63% females and 5.12% males. Distribution of hyperdontia was statistically significant difference between genders, whereas distribution of hypodontia and oligodontia was no significant difference between genders. Hypodontia was the most frequently observed anomaly (3.67%), followed by hyperdontia (0.96%), and oligodontia (0.21%). Oligodontia and hypodontia were more frequent in females (3.98% and 0.26%, respectively), whereas hyperdontia was more frequently observed in males (1.68%). Maxillary lateral incisors were most common missing teeth (2.27%), while the frequency of hyperdontia was most common in premolars.

Conclusion:

The prevalence of teeth number anomalies was 4.84% of dental patients. Maxillary lateral incisors were most common missing teeth, while the frequency of hyperdontia was most common in premolars.

Assessment of hypodontia in the Turkish patients referring to the orthodontic clinic: A retrospective study

OBJECTIVE

The aim of this retrospective study was to assess the prevalence and distribution of hypodontia in the permanent dentition in a sample of Turkish patients who referred to the Ankara Dental Hospital for orthodontic treatment.

MATERIALS AND METHODS

The pre-treatment orthodontic records of 2530 patients, 1382 girls (54.62%) and 1148 boys (45.38%) between the chronological ages of 7 and 16 years, were examined for evidence of hypodontia. The third molars were excluded in this study.

RESULTS

The prevalence of hypodontia in the inspected population was 5% (3.05% for girls, 1.95% for boys). The average number of the congenitally missing teeth per patient was 2.03 (1.08 for girls, 0.95 for boys). The prevalence of the congenitally missing permanent teeth was 34% for the upper laterals, 30% for the lower second premolars, 12.5% for the upper second premolars and 23.5% for the other teeth. Most patients with hypodontia (84.9%) (57.13% for girls, 27.77% for boys) had got missing either one tooth (45.23%) or two teeth (39.67%).

CONCLUSIONS

The prevalence of hypodontia in girls was higher than in boys in this sample of the Turkish patients. The upper laterals and lower second premolars were consecutively the most symmetrically absent teeth. The prevalence of advanced hypodontia was lower than single and symmetrical hypodontia.

Complex analysis of multiple single nucleotide polymorphisms as putative risk factors of tooth agenesis in the Hungarian population

OBJECTIVES

The role was studied of multiple single nucleotide polymorphisms in tooth agenesis in the Hungarian population using a complex approach.

METHODS

Eight SNPs, PAX9 -912 C/T, PAX9 -1031 A/G, MSX1 3755 A/G, FGFR1 T/C rs881301, IRF6 T/C rs764093, AXIN2-8150 A/G, AXIN2-8434 A/G and AXIN2-30224 C/T, were studied in 192 hypodontia and 17 oligodontia cases and in 260 healthy volunteers. Case-control analysis was performed to test both allelic and genotypic associations as well as associations at the level of haplotypes. Multivariate exploratory Bayesian network-based multi-level analysis of relevance (BN-BMLA) as well as logistic regression analysis were performed.

RESULTS

Conventional statistics showed that PAX9 SNP -912 C/T and the MSX1 SNP changed the incidence of hypodontia, although after Bonferroni correction for multiple hypothesis testing, the effects were only borderline tendencies. Using a statistical analysis better suited for handling multiple hypotheses, the BN-BMLA, PAX9 SNPs clearly showed a synergistic effect. This was confirmed by other multivariate analyses and it remained significant after corrections for multiple hypothesis testing (p < 0.0025). The PAX9-1031-A-PAX9-912-T haplotype was the most relevant combination causing hypodontia. Interaction was weaker between PAX9 and MSX1, while other SNPs had no joint effect on hypodontia.

CONCLUSION

This complex analysis shows the important role of PAX9 and MSX1 SNPs and of their interactions in tooth agenesis, while IRF6, FGFR1 and AXIN2 SNPs had no detectable role in the Hungarian population. These results also reveal that risk factors in hypodontia need to be identified in various populations, since there is considerable variability among them.

Meta-analysis and systematic review of factors biasing the observed prevalence of congenitally missing teeth in permanent dentition excluding third molars

No meta-analyses or systematic reviews have been conducted to evaluate numerous potential biasing factors contributing to the controversial results on congenitally missing teeth (CMT). We aimed to perform a rather comprehensive meta-analysis and systematic review on this subject. A thorough search was performed during September 2012 until April 2013 to find the available literature regarding CMT prevalence. Besides qualitatively discussing the literature, the meta-sample homogeneity, publication bias, and the effects of sample type, sample size, minimum and maximum ages of included subjects, gender imbalances, and scientific credit of the publishing journals on the reported CMT prevalence were statistically analyzed using Q-test, Egger regression, Spearman coefficient, Kruskal-Wallis, Welch t test (α=0.05), and Mann-Whitney U test (α=0.016, α=0.007). A total of 111 reports were collected. Metadata were heterogeneous (P=0.000). There was not a significant publication bias (Egger Regression P=0.073). Prevalence rates differed in different types of populations (Kruskal-Wallis P=0.001). Studies on orthodontic patients might report slightly (about 1%) higher prevalence (P=0.009, corrected α=0.016). Non-orthodontic dental patients showed a significant 2% decline [P=0.007 (Mann-Whitney U)]. Enrolling more males in researches might significantly reduce the observed prevalence (Spearman ρ=-0.407, P=0.001). Studies with higher minimums of subjects' age showed always slightly less CMT prevalence. This reached about -1.6% around the ages 10 to 13 and was significant for ages 10 to 12 (Welch t test P<0.05). There seems to be no limit over the maximum age (Welch t test P>0.2). Studies' sample sizes were correlated negatively with CMT prevalence (ρ=-0.250, P=0.009). It was not verified whether higher CMT rates have better chances of being published (ρ=0.132, P=0.177). CMT definition should be unified. Samples should be sex-balanced. Enrolling both orthodontic and dental patients in similar proportions might be preferable over sampling from each of those groups. Sampling from children over 12 years seems advantageous. Two or more observers should examine larger samples to reduce the false negative error tied with such samples.

Investigation of the maxillary lateral incisor agenesis and associated dental anomalies in an orthodontic patient population

Objectives: The aim of this study was to investigate the prevalence of maxillary lateral incisor (MLI) agenesis and associated dental anomalies as well as skeletal patterns in an orthodontic population, and then to compare it with the prevalence of these anomalies in the general population. Study Design: The material of the present study included the records of the 3872 orthodontic patients. The followings were recorded for each subject with the agenesis of MLI: Age, sex, unilateral or bilateral absence, anterior-posterior skeletal relationship of the maxilla and mandible, and presence of associated dental anomalies. The occurrence of these anomalies was compared with data previously reported for the general populations. Results: Of the 3872 patients examined, 94 were found to have agenesis of the MLI, representing a prevalence of 2.4 per cent, with females being more frequently observed. The most commonly found associated anomalies were ectopic eruption of maxillary canines and reduced or peg- shaped contralateral incisor with the frequencies of 21.3 per cent and 20.2 per cent respectively. Conclusions: Patients with agenesis of MLI showed a significantly higher prevalence of skeletal Class III malocclusion compared with the general population. The prevalence of ectopic eruption, transposition, and transmigration of the maxillary canine and reduced or peg- shaped MLIs were significantly increased.

Key words:Hypodontia, missing laterals, associated dental anomalies.

Diagnostic tools used to predict the prevalence of supernumerary teeth: a meta-analysis

OBJECTIVES

This study sought to (i) determine the variations in prevalence figures based on the diagnostic tools employed, and (ii) provide an insight into the prevalence of supernumerary teeth.

METHODS

A comprehensive literature search of the prevalence reports on supernumerary teeth was conducted using two databases. Two independent observers rated these articles according to exclusion and inclusion criteria. 28 papers were included in the analysis to determine the variations in the prevalence figures in relation to the method of diagnosis, and 14 studies were included to estimate the prevalence figures for supernumerary teeth. Statistical analysis was computed using analysis of variance (ANOVA), Student Neumann-Keuls (SNK) test and multiple regression analysis.

RESULTS

Statistically significant differences were evident in the prevalence figures based only on a clinical examination compared with groups that also employed radiographs (p < 0.05, ANOVA, SNK). The prevalence figures for supernumerary teeth ranged from 0% to 3%. The mean prevalence value for the European white population [1.6% (±0.6)] was lower than that of the southern Chinese population [2.7% (±0.14)]. The overall prevalence of supernumerary teeth for males was significantly higher than for females [relative risk = 1.37 (1.13-1.50)].

CONCLUSIONS

Clinical examination plus some types of radiograph(s) are essential for determining the prevalence of supernumerary teeth; nevertheless, it is still underestimated. Several disparities in the prevalence reports make the available data on supernumerary teeth questionable.

Dental development in children with mild-to-moderate hypodontia

INTRODUCTION

The aim of this study was to compare dental development in a group of children with mild-to-moderate hypodontia with a matched group.

METHODS

A study group of 70 children (43 girls, 27 boys) with hypodontia, aged 5.3 to 12.5 years, was matched for race, age, and sex with 140 healthy, normal control subjects. The children's dental ages were calculated by using a modified dental-age estimation method. Differences between dental and chronologic ages were analyzed by t tests, and the correlations between differences in dental and chronologic ages and the numbers of missing teeth were analyzed with the Spearman correlation test.

RESULTS

Dental development in children with mild-to-moderate hypodontia was significantly delayed compared with the control group (P <0.05); however, the mean difference did not exceed 0.3 years in either sex. No correlation was observed between the differences in dental and chronologic age and the severity of hypodontia.

CONCLUSIONS

Children with mild-to-moderate hypodontia had delayed dental development of a few months; this was statistically significant. Because of individual variations, each patient should be carefully examined.

Non-syndromic hypodontia in an Iranian orthodontic population

To investigate the prevalence, characteristics (ie, malocclusion, location, type), and sex distribution of hypodontia in an Iranian orthodontic population. A retrospective study was conducted using periapical and panoramic radiographs and study models of 1,751 subjects attending university orthodontic clinics (870 females, 881 males, age 9-27 years). The Chi-square test was used to analyze differences in the distribution of hypodontia, after stratification by sex and malocclusion type. A total of 197 congenitally missing teeth were observed in 160 patients (9.1%; 74 boys and 86 girls); there were no statistically significant differences between sexes (Chi-square = 0.832, P = 0.36). Hypodontia was more common in patients with Class III malocclusion (45.2%), and was more prevalent in the maxilla (71%) than in the mandible (29%). Maxillary lateral incisors (35.6%) and maxillary second premolars (13.0%) were the most commonly missing teeth, followed by mandibular lateral incisors (9.6%) and mandibular second premolars (8.2%). The prevalence of missing teeth was higher in the anterior segment (incisors and canines) than in the posterior segment (premolars and molars). The prevalence of oligodontia was 0.34%. The prevalence and characteristics of the most frequently missing teeth accorded with the findings of most studies conducted in other countries.

Investigation of hypodontia as clinically related dental anomaly: prevalence and characteristics

Objective. Patients with hypodontia are relatively common in clinical dentistry. This study was performed to determine the prevalence of hypodontia of permanent teeth in Korean orthodontic patients and whether such prevalence is associated with the type of dental clinic, patient gender, or the type of malocclusion. Materials and Methods. Over a five-year period, we evaluated 3,055 patients (mean age, 15.1 years; range 9~30) from two geographically separated orthodontic clinics: 1,479 from University Hospital and 1,576 from a private clinic. Hypodontia was diagnosed using panoramic radiographs, clinical examination, and dental casts. Results. The overall prevalence of hypodontia, excluding the third molars, was 11.3%, and there was no statistically significant association with the type of dental clinic, gender, or malocclusion patterns. The most commonly missing teeth were the mandibular second premolars (44.2%), followed by the mandibular lateral incisors (36.6%), and the maxillary second premolars (34.0%). In both sexes, 86.0% of patients with hypodontia were missing one or two teeth. Conclusion. The relatively high prevalence of hypodontia emphasizes the importance of dental examination in early childhood with radiographic screening for hypodontia as standard public oral health policy and warrants further investigation of the orthodontic treatment strategies to prevent resultant oral health impairments of hypodontia.

Supernumerary teeth in a Turkish population

INTRODUCTION

Our aim in this study was to investigate the frequency, distribution, sex differences, and characteristics of supernumerary teeth in a referred Turkish population.

METHODS

A total of 2599 patients' panoramic radiographs (1360 girls, 1239 boys) were evaluated, including children in both the mixed and the permanent dentitions. Their mean age was 8.6 +/- 0.23 years. Number, location, classification, side, and impaction of supernumerary teeth were evaluated. Furthermore, the development of these teeth was evaluated.

RESULTS

Eighty-four supernumerary teeth were found on 69 radiographs; 9 were deciduous and 75 were permanent teeth. Most supernumerary teeth were in the premaxillary region (67%). Mesiodens (n = 43) was the most frequent supernumerary tooth (51.2%). This was followed by the maxillary lateral incisor (15.5%), the mandibular premolar (14.3%), the maxillary canine (9.5%), the maxillary premolar (6%), the mandibular lateral incisor (2.4%), and the mandibular canine (1.2%). Sixty-two (73.8%) supernumerary teeth were impacted. The male-female ratio was 1.13:1, which was not statistically significant.

CONCLUSIONS

The prevalence of supernumerary teeth in Turkish children was 2.7% in this study.

Problems of supernumerary teeth, hyperdontia or dentes supernumerarii

Supernumerary teeth are extra teeth or toothlike structures which may have either erupted or unerupted in addition to the 20 deciduous teeth and the 32 permanent teeth. This article provides an overview of frequency, distribution and classification of supernumerary teeth. The etiology of supernumerary teeth is still unknown, yet various theories have been presented based on epidemiological studies. Four clinical cases representing the possible manifestations of supernumerary teeth are discussed.

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.

Velocardiofacial syndrome with single central incisor

Three siblings and their mother are reported who all had cytogenetically proven velocardiofacial syndrome (VCFS). One boy had normal dental and craniofacial findings, except for an increased cranial base angle. His sister had only one central incisor in the maxilla. One central incisor had also been missing in the primary dentition. She had no labial frenulum present. Cephalometry showed a small maxillary unit length indicating mild maxillary hypoplasia, an increased anterior face height, steep mandibular plane angle, retruded chin, and a large cranial base angle. Dental measurements showed retroclined lower incisors and increased interincisal angle. A second sister had a cleft of the secondary palate. All permanent teeth were present with the exception of a missing central incisor in the lower jaw: the single lower central incisor was situated in the midline. Her cephalometry showed similar findings as in her sister. All three siblings required palate surgery for speech. Mother was not available for detailed dental and other oral investigations. A single maxillary central incisor has previously been reported in VCFS, but to our knowledge a single central incisor in the mandible has not been reported previously in this entity.

A meta-analysis of the prevalence of dental agenesis of permanent teeth

OBJECTIVE

To gain more insight into the prevalence of dental agenesis.

METHODS

Data from Caucasian populations in North America, Australia and Europe were included in a meta-analysis. For the prevalence of African American, Chinese and Arab groups only indications could be reported because of a limited number of studies.

RESULTS

Agenesis differs by continent and gender: the prevalence for both sexes was higher in Europe (males 4.6%; females 6.3%) and Australia (males 5.5%; females 7.6%) than for North American Caucasians (males 3.2%; females 4.6%). In addition, the prevalence of dental agenesis in females was 1.37 times higher than in males. The mandibular second premolar was the most affected tooth, followed by the maxillary lateral incisor and the maxillary second premolar. The occurrence of dental agenesis was divided into three main groups: common (P2(i) > I2(s) > P2(s)), less common (I1(i) > I2(i) & P1(s) > C(s) & M2(i)) and rare (M2(s) & M1(s) > C(i) > M1(i) & I1(s)). Unilateral occurrence of dental agenesis is more common than bilateral occurrence. However, bilateral agenesis of maxillary lateral incisors is more common than unilateral agenesis. The overall prevalence of agenesis in the maxilla is comparable with that in the mandible, but a marked difference was found between both jaws regarding tooth type. Absence of one or two permanent teeth is found in 83% of the subjects with dental agenesis. A practical application of the results of the meta-analysis is the estimation of dental treatment need.

Supernumerary teeth: review of the literature and a survey of 152 cases

INTRODUCTION

A review of the literature relating to supernumerary teeth is presented along with a survey of 152 cases.

METHODS

The study population consisted of 152 children who visited the department of Paediatric Dentistry at the Jordan University Hospital. Patients ranged in age from 5 to 15 years. Supernumeraries were detected by clinical examination and radiographs.

RESULTS

Males were affected more than females with a sex ratio of 2.2 : 1. Seventy-seven percent of the patients had one supernumerary tooth, 18.4% had double teeth, and 4.6% had three or more supernumeraries. Ninety percent of the supernumerary teeth occurred in the premaxilla, of which 92.8% were in the central incisor region and of these latter 25% were located in the midline. The other 10.4% of the supernumeraries were located in the premolar, canine, molar, and lower central incisor regions. Two cases were of non-syndrome supernumerary teeth. Seventy-five percent of the supernumeraries were conical, 83.1% were in the normal vertical position and 26.5% were erupted. Conical-shaped supernumerary teeth had a significantly higher rate of eruption compared to the tuberculate type.

Severe dental aberrations in familial steroid dehydrogenase deficiency: a new association

Severe numerical dental aberrations are rare, and are most often seen as a part of certain syndromes. We here report on a Saudi Arabian family where first-cousin marriages have caused numerical and structural dental abnormalities linked to autosomal recessively inherited liver diseases. The two latest affected children in this family have had their liver defect successfully treated with fat-soluble vitamins and chenodeoxycholic acid, enabling us to study their dental development. One boy exhibits 11 supernumerary teeth, a general hypomineralisation and enamel hypoplasia, while an affected cousin successfully diagnosed at an early age, so far, only suffers from structural enamel defects. The children are otherwise healthy. There is no resemblance to any known syndromes. We suggest that the supernumerary teeth and the liver disease are caused by the same genetic defect, and represent a new association. The hypomineralisation, however, is most likely to result from vitamin deficiency secondary to malabsorption during the first years of life, before successful treatment was instituted.

Third molar agenesis in human prehistoric populations of the Canary Islands

The occurrence of third molar agenesis was recorded in a sample of 1,492 maxillary and 1,718 mandibular arches belonging to the prehistoric settlers of the Gan Canaria, Tenerife, and La Gomera Islands (Canary Islands). There were significant sex differences only in the Tenerife sample for the maxilla, the incidence in females being higher than in males. In the Gran Canaria sample, the total frequency (male and female combined) of third molar agenesis (individual count method) was 8.7% for the maxilla and 9.3% for the mandible. In the Tenerife and La Gomera samples, the frequencies were 11.1% and 10.7% for the maxilla and 14.6% and 13.3% for the mandible. In the Tenerife sample, the differences between both jaws were statistically significant. The incidence of missing third molars in the mandible was significantly higher in Tenerife than in Gran Canaria, but the other sample differences were statistically nonsignificant. Bilateral absence of third molars was observed in about two-thirds of the specimens examined. Some correlation between both jaws for the occurrence of third molar agenesis was found. The hypotheses that have been proposed in order to explain third molar agenesis in man are discussed. It is suggested that the loss of the third molar in Homo sapiens could be produced by a heterochronic phenomenon of postdisplacement, as a consequence of the phylogenetic tendency toward the delay of the onset of the third molar formation, and that the genetic factors responsible for the absence of these teeth could be related to the general process of delay in tooth formation.

Duplication of the premolar dentition

Multiple supernumerary teeth, often associated with various syndromes, is a relatively uncommon isolated dental anomaly. We present a case of a 9-year-old black male patient with complete duplication of the premolar dentition and premolarization of the permanent canines.

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%.

Congenital defects of the upper lateral incisors (ULI): condition and measurements of the other teeth, measurements of the superior arch, head and face

We surveyed a French male population for the incidence of missing or reduced upper lateral incisors (ULI). In 5,738 subjects, we observed an incidence of 1.59% with one or two reduced ULI (the other normal) and 1.90% with one or two missing ULI (the other normal or reduced), altogether, 3.49% affected subjects. Furthermore, 250 random controls were observed. Agenesis of other teeth is more frequent in propositi. Missing thir molars were 12.4% in controls, 24.0% in propositi with reduced ULI and 39.6% in propositi with two missing ULI. Furthermore, agenesis of incisors, canines and premolars ranges from 0.4% in controls to 1.3% in propositi having reduced ULI and 5.0% in propositi with two missing ULI. So, propositi with reduced ULI are intermediate between the controls and the propositi with missing ULI with respect to the freeuency of agenesis of other teeth. On the other hand, a different ranking is observed with respect to the teeth measurements: reduction of tooth size is more marked in propositi with reduced ULI than in propositi with missing ULI. The reduction mainly affects canines, incisors and to a lesser degree, premolars. Arch length and interpremolar diameters are smaller in propositi with missing ULI, compared with controls.

Variables and criteria in prevalence studies of dental anomalies of number, form and size

Prevalence studies of dental anomalies of number, form and size have varied greatly in their findings. The purpose of this paper is to demonstrate from published studies the effect of variables in sampling techniques and examination methods and to suggest diagnostic criteria. In sampling the ethnic background, the sex distribution, age and derivation of the group studied are shown to be important, but the consumption of near optimum concentrations of fluoride in drinking water does not appear to influence findings. For the examination, a dental history is important and full radiographic coverage essential. Findings should be recorded separately for each dentition, while these anomalies should be studied as a group rather than singly. Diagnostic criteria are proposed for supernumerary teeth, hypodontia, invaginated teeth, double teeth, megadontia and microdontia.

Inheritance of a peculiar type of hypodonitia

A peculiar type of hypodontia is described in two opposite sexed siblings and considered to be inherited as an autosomal recessive trait.