Agenesis Of Other Teeth Research Articles

Sexual Dimorphism in Third Molar Agenesis in Humans with and without Agenesis of Other Teeth.

Sexual dimorphism in the human dentition is of interest from a developmental, evolutionary, and clinical point of view. Here, we investigated sexual dimorphism in third molar agenesis patterns and severity in non-syndromic white European individuals with (group A: 303 individuals) and without agenesis (group B: 303 individuals) of teeth other than the third molars. There was no sexual dimorphism in the patterns or the severity of third molar agenesis within groups. Both sexes showed a higher number of third molar agenesis per individual in group A than in group B. The most common third molar agenesis pattern was that of no third molars. For both females and males, bilateral third molar agenesis was approximately three times more frequent in group A than in group B (p < 0.001), whereas no difference was detected for unilateral agenesis. These findings indicate a strong genetic control of the developmental process of tooth formation, with any disruptions affecting both sexes in a similar manner. Overall, the higher vulnerability of third molar formation could be associated with the evolutionary trend in humans towards a reduced number of molar teeth, which seems to show no sex-related differences.

Dental and skeletal features in subjects with missing maxillary lateral incisors: a case control retrospective study.

The aim of this study was to investigate the relationship between missing maxillary lateral incisors and the mesio-distal (MD) diameters of the teeth. Occlusal and skeletal characteristics of the patients have been analyzed. Seventy-nine patients were included in the study (permanent dentition, mean age: 13.7): 30 subjects with uni- or bilateral maxillary lateral incisors agenesis (study group, SG) and 49 patients with no maxillary lateral incisors agenesis (control group, CG). Orthopanoramics, plaster models and cephalometric analysis were used to perform the evaluations. Compared to the CG, in the SG, most of the teeth had smaller MD diameter. In the bilateral agenesis subgroup, the average differences between teeth diameters were lower than those found by comparing them to the unilateral agenesis subgroup and to the SG. Overjet was reduced on average in the SG. In the SG were found less cases of cross-bite and scissor-bite, less frequency of impaction of at least one tooth and agenesis of other teeth, crowding only in the lower arch, square or ovoid arch shape in the upper arch and square in the lower arch, increased interincisal angle and decreased SN^GoMe. Upper lateral incisors agenesis, especially in cases of unilateral agenesis, is associated with MD teeth reduction. The agenesis of the upper lateral incisors is associated with a greater probability of agenesis affecting other teeth, molar and canine class II, reduced overjet and overbite, square or ovoid upper arch shapes, increased interincisal angle and reduced total divergence.

Third molar agenesis in modern humans with and without agenesis of other teeth.

BackgroundThe number of teeth in the human dentition is of interest both from developmental and evolutionary aspects. The present case-control study focused on the formation of third molars in modern humans aiming to shed more light on the most variable tooth class in the dentition.Materials and MethodsFor this reason, we investigated third molar formation in a sample of 303 individuals with agenesis of teeth other than third molars (agenesis group) and compared it to a sex and age matched control group of 303 individuals without agenesis of teeth other than third molars.ResultsThe prevalence of third molar agenesis in the agenesis group was 50.8%, which is significantly higher than the 20.5% in the control group (p < 0.001). The chance of a missing third molar in the agenesis group was increased by 38.3% (p < 0.001), after controlling for the agenesis in other teeth factor. When considering the amount of missing third molars per individual, a clear tendency towards more missing third molars was evident in the agenesis group compared to the control group. The frequency of bilaterally missing third molars in the agenesis group was 29% in the maxilla, as well as in the mandible, which is about three times higher than the frequency of unilaterally missing third molars (p < 0.001). In the control group, bilaterally missing third molars occurred in 8.6% in the maxilla and 8.9% in the mandible.ConclusionThe present results indicate that genetic factors involved in tooth agenesis affect also the dentition as a whole. Furthermore, the third molars are more vulnerable to factors involved in agenesis of other teeth and they are more often affected as a whole. These findings seem to be associated with the evolutionary trend in humans towards reduced molar number.

Agenesia de terceros molares y su asociación con otras anomalías dentales en una población peruana.

Objective: The purpose of the present study was to determine the association between agenesis of the third molar and other dental anomalies. Materials and Methods: This was an observational, retrospective, cross-sectional and analytical study. The sample included 367 patients, aged 14 to 20 years old with adequate digital panoramic radiography. Patients with syndromes, who had extractions of any third molar and with orthodontic treatment prior to panoramic radiographic examination, were excluded. For data collection, each radiograph was recorded with patient code, sex and age. Results: The prevalence of third molar agenesis was 20.71%. Subsequently, patients were divided into two groups, with agenesis of at least one third molar and a control group; the prevalence of other dental anomalies was 48.69% of third molar agenesis group and 21.31% in the control group. A highly significant association was found between the presence of third molar agenesis and the presence of other tooth abnomalities (p= 0.0000; contingency coefficient = 0.2425).The most frequent dental anomaly was dental inclusion with 20.44% of the population studied; followed by the agenesis of other teeth (7.90%) and finally the presence of supernumerary teeth (1.63%). Conclusions: This study demonstrates that there is an association between third molar agenesis and other dental abnormalities, with a higher prevalence of dental abnormalities in patients with third molar agenesis.

Third molar agenesis: Prevalence and Association with agenesis of other teeth in a Turkish population.

Tooth agenesis is the congenital lack of one or more primary or permanent teeth and it is the most frequently seen dental anomaly. The prevalence of third molar agenesis is significantly higher than the agenesis of other teeth varying from 10% to 40% and shows geographical variance. The aim of this study was to investigate the prevalence of third molar agenesis and its association with other tooth agenesis of jaws. A total of 594 Turkish subjects with or without agenesis of third molars (M3) were included in the study. Dental records and panoramic radiographs were evaluated for M3 agenesis, hypodontia and hyperdontia. Significant differences in the prevalence rate of M3 agenesis between genders among with evaluation of coexistence of M3 and other tooth agenesis were determined by Fisher's exact test. The prevalence of M3 agenesis was determined as 28.7% with no statistically significant gender or location difference. Most common form of M3 agenesis involved one molar followed by two, four and three molars. Agenesis of other teeth was seen among both patient groups with and without M3 agenesis, without significant difference. Turkish population with M3 agenesis did not show increased prevalence of other tooth agenesis, indicating no association between occurrence of agenesis of other teeth and M3.

Association between skeletal morphology and agenesis of all four third molars in Japanese orthodontic patients

The purpose of this study was to clarify differences in skeletal morphologies between male and female orthodontic patients with and without agenesis of all four third molars. A total of 64 patients (32 males and 32 females) with agenesis of all four third molars without agenesis of other teeth were selected as the third molars agenesis group (group 1). In addition, 64 patients (32 males and 32 females) with all these teeth were selected as controls (group 2). Lateral cephalograms taken between the ages of 14 and 30 years were used to compare skeletal morphology between groups 1 and 2 and between sexes. Maxillary length (P < 0.001), lower facial height (P < 0.05), gonial angle (P < 0.001) and mandibular plane angle (P < 0.001) were significantly smaller in group 1 than in group 2. Irrespective of the presence or absence of all four third molars, males had significantly smaller lower facial height (P < 0.01) and mandibular plane angle (P < 0.001) and significantly greater total mandibular length (P < 0.001), mandibular body length (P < 0.001) and mandibular ramus height (P < 0.001) than females. Japanese orthodontic patients with agenesis of all four third molars had significantly small maxillary length, lower facial height, gonial angle and mandibular plane angle.

Dental anomalies in an orthodontic patient population with maxillary lateral incisor agenesis.

ABSTRACTIntroduction: The purpose of this study was to evaluate the prevalence of dental anomalies in a subpopulation of orthodontic patients with agenesis of maxillary lateral incisors (MLI). Methods:The material of the present study included the records of the 1964 orthodontic patients. Panoramic radiographs and dental casts were used to analyze other associated eight dental anomalies, including agenesis of other teeth, dens invaginatus, dens evaginatus, peg shaped MLI, taurodontism, pulp stone, root dilaceration and maxillary canine impaction. Results: Out of the 1964 patients examined, 90 were found to have agenesis of MLI, representing a prevalence of 4.6%. The most commonly found associated-anomalies were agenesis of other teeth (23.3%), peg-shaped MLIs (15.6%), taurodontism (42.2%), and dilacerated teeth (18.9%). Conclusion:Permanent tooth agenesis, taurodontism, peg-shaped maxillary lateral incisor, and root dilacerations are frequently associated with maxillary lateral incisor agenesis.

Symmetrical agenesis of the mandibular third molars and agenesis of other teeth in a Japanese orthodontic population.

This study was conducted to investigate the association between symmetrical agenesis of the mandibular third molars and agenesis of other teeth in Japanese orthodontic patients. A sample of 64 patients with symmetrical agenesis of the mandibular third molars and without agenesis of the maxillary third molars was selected as the third molar agenesis group. In addition, 585 patients with all 4 third molars were selected as controls. The main materials examined for diagnosis of tooth agenesis were panoramic radiographs. The prevalence rate of tooth agenesis was compared between the groups using the chi-squared or Fisher's test, and the odds ratio. Significantly increased occurrence of overall agenesis of the maxillary lateral incisors, and overall and symmetrical agenesis of other teeth including the maxillary and mandibular second premolars and mandibular first molars were observed in the patients with symmetrical agenesis of the mandibular third molars and without agenesis of the maxillary third molars. Irrespective of the presence or absence of symmetrical agenesis of the mandibular third molars, no significant differences in the prevalence rates of overall or symmetrical agenesis of other teeth and specific teeth were noted between the sexes or between the right and left sides of the jaws in the patients without maxillary third molar agenesis. (J Oral Sci 58, 171-176, 2016).

Patterns of bilateral agenesis of maxillary third molars and agenesis of other teeth.

The purpose of this study was to investigate the patterns of bilateral agenesis of maxillary third molars and other tooth agenesis in Japanese orthodontic patients. A group of 262 subjects with bilateral agenesis of maxillary third molars (group A) was divided into three subgroups: group 1A consisting of 114 subjects without agenesis of mandibular third molars; group 2A, 31 subjects with unilateral agenesis of mandibular third molars; and group 3A, 117 subjects with agenesis of all third molars. As controls, 926 other subjects without third molar agenesis were selected (group C). Panoramic radiographs were mainly used to examine for tooth agenesis. The Chi square test and odds ratio were used to make statistical comparisons. The prevalence rates of agenesis of maxillary lateral incisors, mandibular incisors and maxillary and mandibular second premolars, and bilateral agenesis of maxillary lateral incisors and second premolars were significantly higher in any one of the third molar agenesis groups than in the control group. Characteristically, no significant increase in occurrence of bilateral agenesis of mandibular second premolars was demonstrated by the subjects with bilateral agenesis of maxillary third molars. Irrespective of whether unilateral or bilateral agenesis of mandibular third molars is present or not, the Japanese orthodontic patients with bilateral agenesis of maxillary third molars exhibited a significantly increased occurrence of unilateral or bilateral agenesis of maxillary lateral incisors, mandibular incisors and maxillary and mandibular second premolars, except for bilateral agenesis of mandibular incisors and second premolars.

Distribution of permanent canine agenesis in Down syndrome: 15 cases from a Centre for Special Care Dentistry.

The purpose of this study was to investigate the distribution of permanent canine agenesis in subjects with Down syndrome (DS). Subjects with canine agenesis were determined by means of panoramic radiographs from 150 DS subjects attending a center for special care dentistry. Our results confirm the high prevalence of agenetic canines in DS (21 canines, 14%). We found specific effects on the distribution both of phenotype and of location (jaw). In subjects with a mild expression of hypodontia (phenotype nonoligodontia) agenetic canines primarily occurred in the mandibula, whereas in subjects with severe hypodontia (phenotype oligodontia) agenetic canines virtually only occurred in the maxilla. In both phenotypes cooccurrence of an agenetic lateral incisor with an agenetic canine was observed in the maxilla. It was striking that canine agenesis in the mandibula did not cooccur with agenesis of other teeth. These results can be important for treatment planning.

Association between third molar agenesis patterns and agenesis of other teeth in a Japanese orthodontic population

The purpose of this study was to investigate the patterns of third molar agenesis and incidence of agenesis of other permanent teeth in a Japanese orthodontic patient group. A total of 417 Japanese subjects (134 males and 283 females) with agenesis of one or more third molars were divided into four groups according to the agenesis pattern, and 874 other Japanese subjects (302 males and 572 females) without third molar agenesis were assigned to a control group. Panoramic radiographs and medical and dental records were used to examine for tooth agenesis. The Chi-square test and odds ratio were used to make statistical comparisons. The prevalence of third molar agenesis worked out at 32.3% with no statistically significant gender difference. A high prevalence rate of agenesis of third molars, unilateral or bilateral, could be considered characteristic of the Japanese orthodontic population. Significant increases in occurrence of oligodontia, and unilateral or bilateral agenesis of other teeth, including maxillary lateral incisors and maxillary and mandibular second premolars, were observed in all or almost all of the third molar agenesis groups, compared with the controls. A significantly increased prevalence rate of mandibular lateral incisor agenesis was observed in almost all of the third molar agenesis groups. The Japanese patients with third molar agenesis had a significantly increased occurrence of oligodontia, and unilateral or bilateral agenesis of maxillary and mandibular lateral incisors and second premolars, except for bilateral agenesis of mandibular lateral incisors.

Patterns of third-molar agenesis and associated dental anomalies in an orthodontic population

The aim of this study was to investigate the frequency of dental anomalies in orthodontic patients with different patterns of third-molar agenesis, comparing them with patients without third-molar agenesis. A sample of 374 patients with agenesis of at least 1 third molar was divided into 4 groups according to the third-molar agenesis pattern, and a control group of 98 patients without third-molar agenesis was randomly selected from the patient archives. Panoramic radiographs and cast models were used to determine the associated dental anomalies, such as hypodontia, hyperdontia, impaction, dilaceration, microdontia, ectopic eruption, transposition, and transmigration. The Pearson chi-square and Fisher exact tests were used to determine the differences in the distribution of the associated dental anomalies among the groups. The prevalence of agenesis of other teeth (11.2%, n = 42) was significantly greater in our study sample (groups 1-4) than in the control group (group 5) (4.1%, n = 4; P <0.05). When we compared the groups according to the various third-molar agenesis patterns, we found that agenesis of other teeth was more common in patients with agenesis of 3 and 4 third molars. In addition, the patients with agenesis of 4 third molars exhibited maxillary lateral-incisor microdontia more frequently. Another important finding was a higher prevalence of total dental anomalies in patients with agenesis of 3 and 4 third molars compared with the control group. Permanent tooth agenesis, microdontia of maxillary lateral incisors, and total dental anomalies are more frequently associated with agenesis of 4 third molars than with the presence of third molars.

Genetic Factors in the Etiology of Palatally Displaced Canines

Palatal displacement of maxillary canines (palatally displaced canines [PDCs]) can be associated with agenesis of the ipsilateral (adjacent) permanent lateral incisor, suggesting a developmental sequence secondary to a genetic influence on permanent maxillary lateral incisor development. They can also occur with small or normal ipsilateral permanent lateral incisors and or agenesis of other teeth, suggesting an overall effect on the dentition that may be primarily mediated to some degree by genetic factors. PDCs tend to cluster in some families, with segregation analysis suggesting a single gene having a dominant effect with low penetrance. The marked propensity to skip generations and variable presentation also suggests the possibility of a complex etiology with multiple genetic or environmental factors. Studies of linkage or association of specific DNA polymorphisms with the trait in multiple families and/or in large population samples are needed to not only demonstrate a genetic influence but to ultimately determine what those genetic influences are and how they interact with environmental factors. It is time for large clinical studies of patients with PDCs with the use of modern genotyping techniques to test the hypotheses of if, which, and how genetic factors influence this developmental anomaly to ultimately better understand its etiology and treatment. Palatal displacement of maxillary canines (palatally displaced canines [PDCs]) can be associated with agenesis of the ipsilateral (adjacent) permanent lateral incisor, suggesting a developmental sequence secondary to a genetic influence on permanent maxillary lateral incisor development. They can also occur with small or normal ipsilateral permanent lateral incisors and or agenesis of other teeth, suggesting an overall effect on the dentition that may be primarily mediated to some degree by genetic factors. PDCs tend to cluster in some families, with segregation analysis suggesting a single gene having a dominant effect with low penetrance. The marked propensity to skip generations and variable presentation also suggests the possibility of a complex etiology with multiple genetic or environmental factors. Studies of linkage or association of specific DNA polymorphisms with the trait in multiple families and/or in large population samples are needed to not only demonstrate a genetic influence but to ultimately determine what those genetic influences are and how they interact with environmental factors. It is time for large clinical studies of patients with PDCs with the use of modern genotyping techniques to test the hypotheses of if, which, and how genetic factors influence this developmental anomaly to ultimately better understand its etiology and treatment.

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.

Relationship between tooth size and third molar agenesis.

ABSTRACT – The hypothesis that third molar agenesis influences crown size of other permanent teeth was tested on a random sample of 300 children in the age group 14–16 years. The individuals were divided into four groups: Group A, full complement of teeth; B, a‐genesis of one or more third molars; C, agenesis of one or more third molars combined with agenesis of other teeth; D, agenesis of teeth other than third molars. Comparison of mesio‐distal crown diameter showed no significant differences between the groups of boys. In girls, differences in mesiodistal crown diameter were lestricted mainly to Groups A and D and thus were not influenced by the third molar. Calculation of asymmetry revealed no significant differences between groups with and without third molars, nor did the anterior ratio differ between these groups.