Patterns of missing teeth in a population of oligodontia patients

PURPOSE: The purpose of this study was to characterize a population of oligodontia patients and identify patterns of tooth agenesis. MATERIALS AND METHODS: A total of 116 patients with nonsyndromic oligodontia were studied, and the Tooth Agenesis Code (TAC) per quadrant was calculated. Oligodontia was defined as the congenital absence of 6 or more permanent teeth, excluding the third molars. The TAC is a unique number, consistent with a specific pattern of tooth agenesis. The authors suggest the use of an overall TAC with which the dentition throughout the mouth can be presented by a single number. Frequency analysis was used to study the prevalence of various patterns. RESULTS: There was a great diversity of TACs. In the maxilla, agenesis of both premolars and the lateral incisor or the presence of only the central incisor and first molar were the most common patterns. In the mandible, agenesis of the second premolar or both premolars occurred most frequently. CONCLUSIONS: No single pattern of agenesis occurred more than twice when the full mouth was viewed. Hence, the presentation of the dentition in oligodontia is very heterogeneous. Evaluation of treatment strategies in oligodontia patients is a methodologic challenge because homogenous, comparable subgroups of patients are not available.     

Tooth agenesis code (TAC) in complete unilateral and bilateral cleft lip and palate patients

The objective of this study is to characterize and compare tooth agenesis codes and their prevalence in a population of Spanish patients with unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP), and to determine if the extent of the cleft (BCLP or UCLP) was associated with the number of absent teeth. This retrospective cross-sectional human study included 118 patients with complete BCLP (29) or UCLP (89) and permanent dentition from first molar to first molar. Congenitally missing teeth were identified on panoramic radiographs using the tooth agenesis code (TAC) to identify agenesis codes. Agenesis prevalence was 50.6 and 51.7% for UCLP and BCLP patients, respectively. The lateral upper incisor was the most frequently absent tooth, especially in the cleft quadrant. Numbers of absent teeth ranged from 1 to 6. This study represents a different approach from previous agenesis investigations in cleft patients. These Spanish patients showed a high number of ageneses, presenting nineteen different tooth agenesis codes. A total of five TACs were unique, in other words, observed in a single patient in the sample. No statistically significant relationship was found between the extent of the cleft and the number of absent teeth. The TAC system makes it possible to identify agenesis codes with simultaneous absence of teeth not detected in general prevalence studies.     

Tooth agenesis patterns in bilateral cleft lip and palate

Bartzela TN, Carels CEL, Bronkhorst EM, Rønning E, Rizell S, Kuijpers-Jagtman AM. Tooth agenesis patterns in bilateral cleft lip and palate. Eur J Oral Sci 2010; 118: 47–52. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci
Individuals with cleft lip and palate present significantly more dental anomalies, even outside the cleft area, than do individuals without clefts. Our aim was to evaluate the prevalence of tooth agenesis and patterns of hypodontia in a large sample of patients with complete bilateral cleft lip and palate (BCLP). Serial panoramic radiographs (the first radiograph was taken at 10.5–13.5 yr of age) of 240 patients with BCLP (172 male patients, 68 female patients) were examined. Third molars were not included in the evaluation. Agenesis of at least one tooth was present in 59.8% of patients. Upper laterals and upper and lower second premolars were missing most frequently. Using the tooth agenesis code (TAC), 52 different agenesis patterns were identified, of which simultaneous agenesis of 12, 22, 15, 25, 35, and 45 was the most frequent pattern. Nine of the 240 patients showed combined BCLP and oligodontia.     

Dental agenesis patterns of permanent teeth in Apert syndrome

Dental agenesis may either occur as an isolated trait (non-syndromic) or as a component in a congenital syndrome. The aim of the present study was to identify the prevalence of dental agenesis for each type of tooth and to look for dental agenesis patterns in persons with Apert syndrome. Serial panoramic radiographs of 23 individuals (five male patients and 18 female patients) were examined. Third molars were excluded. The prevalence of agenesis for at least one tooth was 34.8%. Up to two missing teeth were found for individuals with Apert syndrome. Maxillary lateral incisors and mandibular second premolars were the most frequently missing teeth. Four different dental agenesis patterns of the entire dentition were identified by using the tooth agenesis code (TAC). Two patterns occurred more frequently, both of which were symmetrical. One involved the simultaneous absence of teeth 12 and 22, and the other showed agenesis of teeth 35 and 45. In conclusion, patients with Apert syndrome were found to exhibit a high prevalence of dental agenesis. All dental agenesis patterns in which more than one tooth was missing were symmetrical.     

Location and Presence of Permanent Teeth in a Complete Bilateral Cleft Lip and Palate Population

Objective:To describe the location and presence of permanent teeth in nonsyndromic complete bilateral cleft lip and palate patients from the Manitoba Centre for Craniofacial Difference.Materials and Methods:Records of 1570 patients dating back to 1958 were assessed in this retrospective chart review.Results:Thirty-eight patients met the inclusion criteria, providing 76 cleft site teeth: A tooth on each side of the cleft was considered to have developed from a single lateral incisor tooth bud. The pattern M was assigned when a tooth was found mesial to the cleft, D when distal, MD when mesial and distal and AB if none was found. Pattern M was noted 9.2% of the time; D, 47.4%; MD, 5.3%; and AB, 38.2%. Teeth outside the cleft site: In the maxilla, agenesis occurred in 11.9% of second premolars and 10.5% of central incisors. In the mandible, agenesis occurred in 4.0% of second premolars, 2.6% of lateral incisors, 2.6% of central incisors, and 2.6% of second molars.Conclusions:The lateral incisor was most commonly found distal to the cleft. Agenesis of the lateral incisor and teeth outside the cleft were more common than in noncleft populations.     

Dental agenesis patterns in Crouzon syndrome

Dental agenesis may be present in an isolated familiar manner, or occur as a part of a syndrome.To date, this clinical trait seems to have been overlooked in patients with Crouzon syndrome.The aim of the present study was to investigate dental agenesis and dental agenesis patterns in a population of persons with Crouzon syndrome in Sweden. Serial panoramic radiographs of 26 individuals with Crouzon syndrome (20 males, 6 females) were examined.Third molars were excluded from the assessment. The prevalence of agenesis for at least one tooth was 42.3%. Each affected patient was found to have up to 5 missing teeth. Upper and lower second premolars were the most frequently congenitally missing teeth. Eleven dental agenesis patterns of the entire dentition were identified, as described by the tooth agenesis code (TAC). All patterns were unique and asymmetric,with only one exception, a symmetric pattern of the maxillary and mandibular second premolars. In conclusion, persons with Crouzon syndrome were found to have a high prevalence of dental agenesis and a remarkable variability of dental agenesis patterns. It is important to be aware of this clinical situation, especially when orthodontic treatment planning for these patients is performed as early as in the mixed dentition.     

Isolated oligodontia: a case presentation and review of the literature

Tooth agenesis is a common developmental anomaly that appears in 2.2-10% of the general population (excluding agenesis of third molars). Congenital tooth agenesis can be either Hypodontia (agenesis of fewer than six teeth excluding third molars) or Oligodontia (agenesis of more than six teeth excluding third molars). Oligodontia can occur either as an isolated condition (non-syndromic oligodontia) or be associated with cleft lip\palate and other genetic syndromes (syndromatic oligodontia). The purpose of this article is to present an unusual case of non-syndromic oligodontia and describe the dental treatment for this condition. The patient was a 25 years old healthy male with a chief complaint of multiple teeth agenesis and TMJ dysfunction. The family history revealed that the mother, grandmother and siblings have also multiple teeth agenesis. Clinical examination revealed missing of nine teeth in the maxilla (12,13, 15,15, 17, 23, 24, 25, 27) and 10 teeth in the mandible (32, 33, 34, 35, 37, 42, 43, 44, 45, 47). The patient's dental treatment plan included preparing provisional over-dentures, orthodontic treatment and dental implants (after extractions of the deciduous teeth). In the discussion of the article the pathology and the genetics of oligodontia are reviewed.     

Patterns of non-syndromic permanent tooth agenesis in a large orthodontic population

ObjectiveThe aim of this study is to explore patterns of non-syndromic permanent tooth agenesis in a large orthodontic patient group.DesignA record review was performed in various orthodontic clinics to identify white patients with non-syndromic permanent tooth agenesis, excluding 3rd molars. Four hundred and fourteen subjects fulfilled the inclusion criteria.ResultsIn the 414 subjects with tooth agenesis, approximately 70% presented 1–2 missing teeth. Symmetric agenesis patterns were often observed in the sample (by jaw, by side, or crossed quadrants), with prevalence approaching 30% for cases with contralateral tooth agenesis within a jaw. In cases with 1 or 2 missing teeth, from the total number of potential tooth agenesis patterns in the sample, a certain part was evident, limiting the variation to 27.8% (44/158). In the entire sample, both in the maxilla and the mandible a certain incisor/premolar agenesis phenotype was observed in 59.0% of cases in isolated form.ConclusionsAlthough there was variation in the tooth agenesis patterns, our findings suggest the involvement of particular genetic, epigenetic, and/or environmental factors in the formation of the entire dentition, which often lead to specific tooth agenesis phenotypes in cases where this process is disrupted.The present study provides a comprehensive categorization of orthodontic cases with tooth agenesis and can assist in planning future epidemiological and genetic studies.     

A numeric code for identifying patterns of human tooth agenesis: a new approach

Human tooth agenesis involves the absence of one or more teeth and often refers to a genetic or a developmental disorder. Identifying whether certain patterns of tooth agenesis are more prevalent than others may prove valuable for treatment planning, as well as for genetic research into its etiology and development. In the present article a method is described where unique values are assigned to patterns of tooth agenesis. Using the idea of binary arithmetic, the absence or presence of teeth are represented by 1 and 0, and translated into corresponding unique values, the Tooth Agenesis Code (TAC). This procedure has an advantage over existing methods in that it allows for easier data analysis. The method described in this article can advance genetic research towards the etiology of tooth agenesis, allows researchers to communicate unequivocally the phenotypes of their studied cases and it can be used in other areas of oral pathology that also require pattern recognition.     

Third molar agenesis as a potential marker for craniofacial deformities

The identification of clinical patterns of tooth agenesis in individuals born with craniofacial deformities may be a useful tool for risk determination of these defects. We hypothesize that specific craniofacial deformities are associated with third molar agenesis.ObjectiveThe aim of this study was to identify if third molar agenesis could have a relation with other craniofacial structure alterations, such as cleft lip and palate, skeletal malocclusion, or specific growth patterns in humans.DesignData were obtained from 550 individuals ascertained as part of studies aiming to identify genetic contributions to oral clefts. 831 dental records of patients aged over eight years seeking orthodontic treatment were also included. SN-GoGn angle were used to classify the growth pattern (hypo-divergent, normal and hyper-divergent), and the ANB angle was used to verify the skeletal malocclusion pattern (Class I, II and III). Panoramic radiographs were used to determine third molar agenesis.ResultsA high frequency of third molar agenesis among individuals born with cleft lip with or without cleft palate (55%), as well as among their relatives (93.5%) was found. Third molar agenesis was not associated to skeletal malocclusion or growth pattern.ConclusionIt appears that third molar agenesis is associated with the disturbances that lead to cleft lip and palate.     

Prevalence of abnormalities in dental structure, position, and eruption pattern in a population of unilateral and bilateral cleft lip and palate patients.

OBJECTIVE: To evaluate the dental characteristics of patients subjected to a protocol that included early secondary gingivoalveoloplasty (ESGAP). DESIGN: Panoramic radiographs of 87 patients with unilateral cleft lip and palate (UCLP) and 29 with bilateral cleft lip and palate (BCLP) were evaluated. Missing and supernumerary teeth were also quantified on the cleft and noncleft side and in the maxilla and mandible. Crown and root malformations and tooth rotations were quantified. A subsample in permanent dentition was extrapolated to analyze canine eruption patterns. RESULTS: A total of 48.8% of the UCLP patients presented with missing permanent lateral incisors in the cleft area and 6.1% contralaterally. A total of 4.9% presented with missing second maxillary premolars on the cleft site and 1.2% contralaterally. A total of 7.3% presented with supernumerary lateral incisors, and 45% of the BCLP cleft sites presented with missing lateral incisors, while 25% of the cleft sites presented second maxillary premolars agenesis. Five percent of the cleft sites presented with supernumerary lateral incisors. Evaluation of the subsample in permanent dentition showed that 15.5% had a canine retention and 4.4% of the canines had to be surgically exposed. A significant association was observed between canine inclination and retention but not with absence of the lateral incisor. CONCLUSIONS: The frequency of dental anomalies in this sample was similar to other cleft populations. As surgical trauma has been suggested to damage forming teeth, the results of this study indicated that ESGAP has no detrimental influence on subsequent dental development.     

Prevalence and patterns of permanent tooth agenesis in individuals with Down syndrome: a meta‐analysis

The aims of the present study were to evaluate the prevalence and patterns of permanent tooth agenesis in individuals with Down syndrome, using meta‐analysis methodology. Two independent investigators carried out a literature search to locate articles pertaining to permanent tooth agenesis in individuals with Down syndrome. The outcomes of interest were the prevalence and pattern of permanent tooth agenesis. Thirteen articles were selected for inclusion. The estimated overall prevalence of permanent tooth agenesis, excluding third molars, was 54.6% (95% CI: 44–66%). Considerable heterogeneity was present across the studies. Among subjects with tooth agenesis, approximately half had three or more missing teeth. The permanent teeth with the highest prevalence of agenesis were the maxillary lateral incisor (27%), mandibular second premolar (21%) and maxillary second premolar (18%). The single most commonly absent tooth, however, was the mandibular left second mandibular premolar (19.9%), followed by the maxillary left lateral incisor (19.4%). Little data describing specific tooth‐agenesis patterns were available. In conclusion, individuals with Down syndrome display high prevalence rates and severity of agenesis of permanent teeth. Proper and timely diagnosis of missing permanent teeth is thus necessary, to allow a more comprehensive long‐term treatment plan and a more favorable prognosis in these individuals.     

Is missing maxillary lateral incisor in complete cleft lip and palate a product of genetics or local environment

Objective:To test the null hypothesis: Subjects with isolated complete unilateral cleft lip and palate (UCLP) show no differences in overall frequency of tooth agenesis (hypodontia), comparing a subsample with cleft-side maxillary lateral incisor (MxI2) agenesis to a subsample without cleft-side MxI2 agenesis. Findings could clarify the origins of cleft-side MxI2 agenesis.Materials and Methods:Tooth agenesis was identified from dental radiographs of 141 subjects with UCLP. The UCLP cohort was segregated into four categories according to the status and location of MxI2 in the region of the unilateral cleft: group M: subjects with one tooth, located on the mesial side of the alveolar cleft; group D: subjects with one tooth, located on the distal side of the alveolar cleft; group MD: subjects with two teeth present, one mesial and one distal to the cleft; and group ABS: subjects with lateral incisor absent (agenesis) in the cleft area.Results:The null hypothesis was rejected. Among UCLP subjects, there was a twofold increase (P < .0008) in overall frequency of tooth agenesis outside the cleft region in a subsample with cleft-side MxI2 agenesis (ABS), compared to a subsample presenting with no agenesis of the cleft-side MxI2 (M+D+MD).Conclusions:Cleft-side MxI2 agenesis in CLP subjects appears to be largely a genetically controlled anomaly associated with cleft development, rather than a collateral environmental consequence of the adjacent cleft defect, since increased hypodontia involving multiple missing teeth observed remote from a cleft clearly has a significant genetic basis.     

Tooth abnormalities and soft tissue alterations in patients with G/BBB syndrome

Objective: The G/BBB syndrome is an X‐linked recessive disorder characterized by eye anomalies, laryngotracheoesophageal cleft, congenital heart disease, genitourinary anomalies and gastrointestinal disorders. Patients may also present cleft lip and palate, high‐arched palate and thin upper lip. This study aimed to investigate the occurrence of tooth abnormalities and soft tissue changes in patients with G/BBB syndrome. Design: Cross‐sectional. Subjects and methods: Twenty‐one patients with G/BBB syndrome were analyzed as to the presence of tooth abnormalities and soft tissue alterations. Main outcome measures: The prevalence of tooth agenesis and supernumerary teeth was compared to patients without morphofunctional alterations, matched for gender and age. Results: All patients had complete cleft lip and palate; 95.23% of patients presented tooth abnormalities, mainly hypoplastic alterations, with predominance of alterations of number, followed by alterations of structure, shape and position. The frequency of tooth agenesis and supernumerary teeth was significantly higher compared with the control group; 11 patients presented incisiform supernumerary teeth in the mandibular anterior region. Ankyloglossia was observed in 11 of 21 patients. Conclusion: The presence of mandibular anterior supernumerary teeth and ankyloglossia should be investigated in the clinical evaluation of patients with suspected diagnosis of the G/BBB syndrome.     

Sexual dimorphism,pattern of third molar and mandibular second premolar agenesis in Indian paediatric orthodontic patients

Objective

To determine and compare the prevalence and pattern of agenesis of third molar and mandibular second premolar in paediatric orthodontic patients of age group 9–15 for sexual dimorphism.

Tooth loss in a selected population in Saskatoon

Tooth mortality in a population can provide information about the prevalence of dental disease, availability of dental care and attitudes about tooth extraction. The tooth mortality of patients presenting for treatment at the University Dental Clinic (Saskatoon, Canada) during the school terms 1981-1986 was determined to provide base-line data during a time when the dentist-to-population ratio has been increasing, and to compare the results with similar studies carried out in Britain and Greece. The data were analyzed according to the same quinquennial age groups as in the other studies. There were no statistically significant differences between the two time periods at all ages and therefore the data were pooled. Totally edentulous persons were excluded from the analysis for comparison purposes. The prevalence of tooth loss increased with age with a rapid period of tooth loss encompassing the mean ages of 34 to 47 years, a slowing of further loss up to the mean age of 62 and thereafter, a further increase. The initial rapid loss was most apparent for molar teeth and least apparent for mandibular incisor teeth. With the exception of first molars, more teeth were lost in the maxilla than in the mandible. The present data are similar to the findings reported in British and Greek studies.     

同源异型盒基因-1与非综合征型多数牙先天性缺失

牙缺失是常见的颌面发育异常之一,在恒牙列中的发病率高达20%,而其表现程度也存在较大差异.在过去的数十年中,遗传连锁和分子生物学研究使得部分综合征和非综合征型牙缺失的基因突变得以定位.尽管作用机制尚未明了,但现已知其中所涉及的重要突变因子包括了编码转录因子的同源异型盒基因(msx)-1、双链复合蛋白基因(pax)-9和轴抑制基因(axin)-2.下面从近年来国内外有关先天性牙缺失的病例报告、致病基因分析以及分子生物学和生物化学等研究方面就msx-1基因与非综合征型牙缺失的关系进行综述.     

Prevalence and genetic basis of tooth agenesis

Tooth agenesis or hypodontia is one of the most common anomalies of the human dentition, characterized by the developmental absence of one or more teeth. Many studies have reported that the prevalence of congenital absence of permanent teeth varies from 3% to 11% among European and Asian populations. Recent advances in the fields of molecular biology and human genetics have improved our understanding of the cause of tooth agenesis. In this review, we assess the previous literature on prevalence of tooth agenesis comparing the Japanese with other racial populations, and describe the recent genetic studies associated with hypodontia in human and mouse models.