Patterns Of Tooth Agenesis Research Articles

Novel MSX1 Gene Variants in Chinese Children with Non-Syndromic Tooth Agenesis: A Clinical and Genetic Analysis

Background: Tooth agenesis is the most frequently occurring genetic developmental anomaly in clinical dentistry. The MSX1 gene, essential for tooth development, has been associated with non-syndromic tooth agenesis. This study aims to identify novel MSX1 variants associated with this condition and to understand their impact on tooth development. Methods: This study involved the genetic analysis of two children presenting with non-syndromic tooth agenesis. Conservation analysis and 3D structural modeling were conducted to assess the pathogenicity of these variants. Additionally, a review of 108 patients with known MSX1 variants was performed to identify patterns of tooth agenesis. Results: We discovered two novel MSX1 variants, c.823 T>G and c.890 A>G, located in the second exon of the MSX1 gene. The identified MSX1 variants, c.823 T>G and c.890 A>G, were predicted to be pathogenic. Conservation analysis showed that the impacted amino acids are highly conserved across species, and 3D structural analysis indicated potential disruptions to protein function. Among the 108 patients reviewed, a consistent pattern of tooth agenesis was observed, with the most frequently missing teeth being the maxillary second premolars, the mandibular second premolars, and the maxillary first premolars. Conclusions: This research broadens the known range of MSX1 gene variants and deepens our comprehension of the genetic foundations of non-syndromic tooth agenesis. The findings provide valuable insights for genetic counseling and future research into tooth development, emphasizing the importance of MSX1 in dental anomalies.

Patterns of Congenital Tooth Agenesis and Crown Width in Patients with Alveolar Clefts in Guizhou, China: A Retrospective Study

Objective This study aimed to investigate the prevalent pattern of congenital tooth agenesis and the development of crown width in patients with alveolar clefts in Guizhou, China. Methods The imaging data and complete medical record information of 222 patients who met the criteria were studied. The rate of tooth agenesis, tooth agenesis patterns, type of cleft, gender, and crown width in patients with alveolar cleft were counted. Results Twenty-two congenital tooth agenesis patterns were statistically identified in patients with alveolar clefts by the tooth agenesis code method. The rate of congenital tooth agenesis in patients with alveolar cleft was 72.5%, and the most common missing teeth were lateral incisors. The rate of tooth agenesis was higher in bilateral alveolar cleft (87.1%) than in unilateral alveolar cleft (67.4%). No correlation was found between gender and tooth agenesis patterns, tooth agenesis rate, or number of missing teeth. Crown width in patients with alveolar clefts is less than normal. No correlation was found between the number of missing teeth and crown width. Conclusions The congenital tooth agenesis patterns and tooth agenesis rates in patients with alveolar clefts in Guizhou, China, were related to the type of cleft, independent of gender. The crown widths in patients with alveolar clefts were smaller than normal, irrespective of the number of tooth agenesis.

Prevalence of tooth agenesis and supernumerary teeth related to different Thai cleft lip and cleft palate populations

BackgroundPattern of dental anomalies encountered in cleft patients shows subtle signs of genetic involvement. This study aimed to evaluate the prevalence and pattern of tooth agenesis and supernumerary teeth in Thai cleft population according to the cleft type.MethodsData collected from patients with cleft lip and palate, who had been treated at Tawanchai Cleft Center, Khon Kaen University, Thailand, available during year 2012–2022, were investigated. Records from 194 patients with non-syndromic clefts met the inclusion criteria. Standard dental records, and at least either orthopantomogram (OPG) or cone beam computed tomography (CBCT), were examined. Statistical analysis was performed using chi-square and binominal test (p ≤ 0.05).ResultsPrevalence of tooth agenesis was higher (77.3%) than that of supernumerary teeth (5.7%) and was more common in bilateral cleft lip and palate (BCLP) (88.1%) than in unilateral cleft lip and palate (UCLP) (72.6%) (p = 0.017). The upper lateral incisor was more frequently affected (46.4%), followed by the upper second premolar. The number of missing teeth observed on the left side was significantly higher. Patients with left UCLP (ULCLP) had the highest prevalence of tooth agenesis. A total of 41 tooth agenesis code (TAC) patterns was found. The prevalence of supernumerary teeth was comparable with 6.6% of ULCLP, 5.1% of BCLP, and 4.5% of URCLP. Tooth-number anomalies were observed more often in the BCLP and were most likely to occur on the left side of the maxilla. Both types of anomalies could be featured in a small proportion of cleft patients.ConclusionsMore than half of the patients with non-syndromic cleft lip and palate in this study, presented with tooth-number anomalies. Tooth agenesis was approximately 10-time more prevalent than supernumerary teeth. Tooth agenesis was likely to appear on the left-side of the maxilla regardless of the laterality of the cleft.

Patterns of tooth agenesis in individuals with Down syndrome: A secondary analysis using the Tooth Agenesis Code.

Tooth agenesis (TA) is common in Down syndrome (DS). It is unknown whether this agenesis occurs in specific patterns, which is important regarding treatment planning and aetiological research. This study aimed to aggregate and analyze patterns of TA, excluding third molars, in individuals with DS using the tooth agenesis code (TAC). The study was designed as a secondary analysis, following STROSA guidelines. The search (MEDLINE-PubMed) and selection process resulted in six included studies encompassing 241 individuals with DS. TA data were systematically converted into TACs and analyzed per dentition, per jaw, and per tooth type. Symmetry was evaluated. The prediction was calculated for oligodontia. In the 155 cases with TA 86 distinct Overall-TAC patterns were identified. The most common patterns were bilateral maxillary lateral incisor agenesis (TAC002.002.000.000;10.3%), bilateral mandibular second premolar agenesis (TAC000.000.016.016;5.8%), and unilateral left maxillary lateral incisor agenesis (TAC000.002.000.000;5.2%). Symmetry in TA patterns was observed in 49.6% of TA cases in the maxilla and 52.3% in the mandible. The simultaneous absence of both mandibular central incisors had a large predictive value for oligodontia (OR12.44;95% CI:4.97-31.84; p<.001). Predominant TA patterns exist in DS. Observation of mandibular central incisor agenesis can promote early diagnosis of oligodontia in DS.

“Examining the link between tooth agenesis and papillary thyroid cancer: is there a risk factor?” Observational study

BackgroundMutations in one or multiple genes can lead to hypodontia and its characteristic features. Numerous studies have shown a strong genetic influence on the occurrence of hypodontia, and identified several genes, including AXIN2, EDA, FGF3, FGFR2, FGFR10, WNT10A, MSX1, and PAX9, that are directly associated with dental agenesis and carcinogenesis. The objective of this study was to investigate the occurrence and pattern of tooth agenesis, microdontia, and palatally displaced canine (PDC) in women diagnosed with papillary thyroid cancer (PTC), compared to a control group of women without any malignancy or thyroid disease.Materials and methodsThis case–control study was carried at the Department of Orthodontics, School of Dental Medicine University of Zagreb, and Department of Oncology and Nuclear Medicine Sestre Milosrdnice University Hospital Centre. The study involved a clinical examination and evaluation of dental status, panoramic X-ray analysis, and assessment of medical and family history of 116 female patients aged 20–40 with PTC, as well as 424 females in the control group who were of similar age.ResultsThe prevalence of hypodontia, microdontia, and PDC was statistically higher in women with PTC than in the control group. The prevalence rate of hypodontia was 11.3% in the experimental group and 3.5% in the control group. The experimental group showed a higher occurrence of missing upper lateral incisors, lower left central incisors, and all the third molars (except the upper left) compared to the control group. Women with PTC showed the prevalence of PDC significantly higher than the control group (3.5%, 0.7%, p = 0.002). The probability of hypodontia as a clinical finding increases 2.6 times, and microdontia occurs 7.7 times more frequently in women with PTC.ConclusionOur study suggests a possible link between odontogenesis and PTC. The absence of permanent teeth may increase the likelihood of PTC in women. Leveraging the age-7 orthopantomogram to identify women at high risk for PTC within a critical early detection window could significantly improve oral health outcomes and PTC prognosis through proactive interventions.

Clinical analysis of nonsyndromic oligodontia phenotypes.

To provide references, this study investigated the clinical characteristics of patients with nonsyndromic oligodontia. The information of 178 patients with oligodontia was collected, including histories, oral examinations, and panoramic radiographs. Tooth agenesis characteristics were calculated and evaluated. All the data were statistically analyzed with SPSS 24.0 software. No significant difference in the number of missing teeth was found between sexes nor between the right and left sides, and congenitally missing teeth affected the maxillary arch (P<0.05). The highest prevalence of tooth agenesis was observed in the mandibular second premolars. In the maxillary arch, the most common pattern of tooth agenesis was agenesis of the bilateral first and second premolars. The agenesis of the bilateral second premolars was observed in the mandibular arch. The prevalence of a symmetric pattern between the right and left quadrants was significantly higher than that of matched patterns between the maxillary and mandibular antagonistic quadrants. Approximately 16.85% of patients with nonsyndromic oligodontia were affected by other tooth-related anomalies. The common patterns of tooth agenesis were successfully identified in patients with nonsyndromic oligodontia. Dentists need to provide multidisciplinary treatments for patients with nonsyndromic oligodontia because of variations in occluding and full-mouth tooth agenesis patterns.

Patterns and sexual dimorphism of non-syndromic hypodontia among a French orthodontic population

ObjectivesThis retrospective study aimed to estimate the prevalence of non-syndromic congenitally missing teeth (CMT) and to explore the frequency of CMT patterns in a French orthodontic population. In addition, the study sought to assess sex-based differences in CMT patterns. DesignPanoramic radiographs of 4569 orthodontic patients between 9 and 21 years-old performed over a 16-year period (2006–2022) were examined to identify non-syndromic tooth agenesis, excluding third molars. A chi-square test or a Fisher exact test were used to determine the difference in the prevalence of tooth agenesis between sex and between arches. ResultsTooth agenesis was observed in 7.3% of the sample (7.9% for females and 6.6% for males). Approximately 86% of the included subjects presented 1 or 2 missing teeth. Single tooth agenesis was significantly more frequent in females than males (p = 0.002, χ2). In total, 23 of the 67 different patterns of CMT observed, were present more than once. 75.5% of male patients and 79.5% of female patients presented one or both missing lateral incisors or second premolars, rarely affected at the same time. This study showed no sex difference in the patterns of tooth agenesis. LimitationsThis study has limitations due to its retrospective nature and our findings apply solely to an orthodontic population from a white ethnic background. ConclusionsClinicians should be aware of this particular incisor/premolar phenotype regardless of biological sex. Issues associated with congenitally missing teeth can be managed more effectively with early teenage diagnosis.

PAX9 mutations and genetic synergism in familial tooth agenesis.

Familial tooth agenesis (FTA) is one of the most common craniofacial anomalies in humans. Loss-of-function mutations in PAX9 and WNT10A have been known to cause FTA with various expressivity. In this study, we identified five FTA kindreds with novel PAX9 disease-causing mutations: p.(Glu7Lys), p.(Val83Leu), p.(Pro118Ser), p.(Ser197Argfs*23), and c.771+4A>G. Concomitant PAX9 and WNT10A pathogenic variants found in two probands with severe phenotypes suggested an effect of mutational synergism. All overexpressed PAX9s showed proper nuclear localization, excepting the p.(Pro118Ser) mutant. Various missense mutations caused differential loss of PAX9 transcriptional ability. PAX9 overexpression in dental pulp cells upregulated LEF1 and AXIN2 expression, indicating a positive regulatory role for PAX9 in canonical Wnt signaling. Analyzing 176 cases with 63 different mutations, we observed a distinct pattern of tooth agenesis for PAX9-associated FTA: Maxillary teeth are in general more frequently affected than mandibular ones. Along with all second molars, maxillary bicuspids and first molars are mostly involved, while maxillary lateral incisors and mandibular bicuspids are relatively less affected. Genotypically, missense mutations are associated with fewer missing teeth than frameshift and nonsense variants. This study significantly expands the phenotypic and genotypic spectrums of PAX9-associated disorders and reveals a molecular mechanism of genetic synergism underlying FTA variable expressivity.

Patterns of nonsyndromic tooth agenesis and sexual dimorphism

BackgroundSex dimorphism has been implicated in oral health differences and the pathogenesis of oral diseases, such as tooth agenesis, periodontal disease, dental caries, and tooth loss. Tooth agenesis (TA) is one of the most common developmental anomalies in humans, and its prevalence and patterns are different across ethnic groups. The aim of this study was to investigate the phenotypes and sex-associated patterns of nonsyndromic tooth agenesis (TA) in Thai dental patients.MethodsOne thousand ninety panoramic radiographs were examined. One hundred and one subjects (37 males, 64 females, 15–20 years-old) with nonsyndromic TA were evaluated. Differences in TA prevalence between groups were analyzed using the chi-square or Fisher exact test.ResultsThe TA prevalence, excluding third molars, was 9.3% and more frequently found in the mandible compared with the maxilla. The maxilla demonstrated a higher prevalence of first premolar agenesis than the mandible (P = 0.012), while the mandible had a higher prevalence of second premolar agenesis than the maxilla (P = 0.031). There were significantly more males missing one tooth than females, however, there were more females missing two or more teeth than males (P = 0.042). A missing maxillary left lateral incisor was significantly more frequent in males (P = 0.019), while a missing mandibular right lateral incisor was more frequent in females (P = 0.025). In females, the pattern of two mandibular lateral incisors agenesis was the most common and significantly present in females more than males (P = 0.015). In contrast, the pattern of one mandibular left lateral incisor agenesis was only observed in males and significantly found in males more than females (P = 0.047).ConclusionsWe demonstrate sex-associated differences in nonsyndromic tooth agenesis. The prevalence of single tooth agenesis was higher in males, while that of two or more teeth agenesis was higher in females. We found different patterns of lateral incisor agenesis between males and females.

Dose Dependence Effect in Biallelic WNT10A Variant-Associated Tooth Agenesis Phenotype.

The goal of this study was to identify the pathogenic gene variants in patients with odonto-onycho-dermal dysplasia syndrome (OODD) or nonsyndromic tooth agenesis. Four unrelated individuals with tooth agenesis and their available family members were recruited. Peripheral blood was collected from four probands and five family members. Whole-exome sequencing (WES) and Sanger sequencing were used to identify the pathogenic gene variants. The harmfulness of these variations was predicted by bioinformatics. We identified four biallelic variants of the WNT10A gene in four patients, respectively: the proband#660: c.1176C &gt; A (p.Cys392*) and c.812G &gt; A (p.Cys271Tyr); the proband#681: c.637G &gt; A (p.Gly213Ser) and c.985C &gt; T (p.Arg329*); the proband#829: c.511C &gt; T (p.Arg171Cys) and c.637G &gt; A (p.Gly213Ser); and the proband#338: c.926A&gt; G (p.Gln309Arg) and c.511C &gt; T (p.Arg171Cys). Among them, two variants (c.812G &gt; A; p.Cys271Tyr and c.985C &gt; T; p.Arg329*) were previously unreported. Bioinformatics analysis showed that the pathogenicity of these six variants was different. Tertiary structure analysis showed that these variants were predicted to cause structural damage to the WNT10A protein. Genotype-phenotype analysis showed that the biallelic variants with more harmful effects, such as nonsense variants, caused OODD syndrome (#660 Ⅱ-1) or severe nonsyndromic tooth agenesis (NSTA) (#681 Ⅱ-1); the biallelic variants with less harmful effects, such as missense variants, caused a mild form of NSTA (#829 Ⅱ-2 and #338 Ⅱ-1). Individuals with a heterozygous variant presented a mild form of NSTA or a normal state. Our results further suggest the existence of the dose dependence of WNT10A pathogenicity on the tooth agenesis pattern, which broadens the variation spectrum and phenotype spectrum of WNT10A and could help with clinical diagnosis, treatment, and genetic counseling.

Oral rehabilitation of tooth agenesis frequently starts in paediatric dentistry. A retrospective analysis of 625 patients.

As oral rehabilitation of tooth agenesis usually begins at a very young age, it is important to plan the therapy in advance in order to prepare the patient for the final treatment after the end of skeletal and dental growth. The diverse patterns of tooth agenesis require interdisciplinary oral rehabilitation adapted to individual factors like patient's age, number of missing teeth, and alveolar-bone development. The aim of the present high volume single-center study was to provide an overview of the management of patients with tooth agenesis, in terms of treatment approaches, associations, and long-term implant survival, over a period of 30 years. Descriptive analyses were performed to analyse treatment approaches and and how they reated to severity of agenesis as well as patients' gender and age. Kaplan-Meier survival curves and log-rank-tests were used to investigate implant survival over time. Treatment starts usually in childhood or adolescence; orthodontic therapy was the most common treatment. All treatment options showed similar high survival rates. External bone augmentation might be a risk-factor for implant loss.

Prevalence and Patterns of Permanent Tooth Agenesis among Orthodontic Patients—Treatment Options and Outcome

(1) Background: tooth agenesis is a very common dental anomaly of the human dentition most often affecting the maxillary anterior region, mandibular and maxillary premolar regions. (2) Purpose: the present study was aimed to evaluate the prevalence and patterns between bilateral and unilateral tooth agenesis among orthodontic individuals and to illustrate the treatment options for missing teeth and the outcome. (3) Materials and methods: Pre-treatment records, photographs and radiographs, of 3000 consecutively treated orthodontic individuals from the post-graduate clinic of Tel Aviv University were surveyed to detect permanent tooth agenesis in either dental arch. The data was recorded according to gender, and location and quantified between unilateral and bilateral agenesis. Descriptive and comparative statistical analysis were performed with t-test and Chi-square test (p &lt; 0.05). (4) Results: permanent teeth agenesis, excluding third molars, was found in 326 individuals (11%), 139 males (43%) and 187 females (57%). Of them, 59% were missing in the maxilla and (41%) were missing in the mandible. A higher prevalence rate of bilateral missing lateral incisors in the maxilla (62 cases), followed by bilateral missing second premolars in the mandible (44 cases) compared with unilateral missing teeth. (5) Conclusions: this study found an overall prevalence of missing permanent teeth in orthodontic patients to be 11%. The female: male prevalence ratio was roughly 3:2, with a greater tendency in the maxilla than in the mandible. A higher prevalence of bilateral missing maxillary lateral incisors and mandibular second premolar than unilateral missing teeth.

Prevalence of Dental Anomalies in Taiwanese Children with Cleft Lip and Cleft Palate

The aim of this study was to investigate the prevalence of tooth agenesis, tooth malformation, and eruption patterns of upper canines/first premolars in Taiwanese children. A total of 132 cleft lip and cleft palate (CLCP) patients (82 boys and 50 girls) underwent alveolar bone grafting (ABG) between 2012 and 2022. The patients’ dental records and X-ray images were inspected. We examined dental anomalies, including congenital missing teeth, microdontia, and transposition from the upper canines to the upper first premolars in these CLCP patients. Additionally, we investigated the mean ABG operation age (9.27 ± 0.76 years) of our patient; 40.9% of them received pre-ABG orthodontic treatment at 8.72 ± 0.70 years. Among the 132 cleft subjects, the prevalence of tooth agenesis is 73.5% (97/132). The most frequently missing teeth are the maxillary lateral incisors (right side: 46.2%; left side: 47.0%). In this study, microdontia are found in all the upper incisors, of which the highest percentage (18.9%) is observed in the upper left lateral incisors. The prevalence of upper canine and first premolar transposition is 10.6%. The pattern of tooth agenesis and microdontia of the upper lateral incisors shows a strong correlation with the cleft sites of these CLCP patients in our study. These results may support the idea that the patterns of dental anomalies in CLCP patients are region-specific.

Tooth Agenesis Patterns in Orofacial Clefting Using Tooth Agenesis Code: A Meta-Analysis.

Individuals with orofacial clefting (OFC) have a higher prevalence of tooth agenesis (TA) overall. Neither the precise etiology of TA, nor whether TA occurs in patterns that differ by gender or cleft type is yet known. This meta-analysis aims to identify the spectrum of tooth agenesis patterns in subjects with non-syndromic OFC and controls using the Tooth Agenesis Code (TAC) program. An indexed search of databases (PubMed, EMBASE, and CINAHL) along with cross-referencing and hand searches were completed from May to June 2019 and re-run in February 2022. Additionally, unpublished TAC data from 914 individuals with OFC and 932 controls were included. TAC pattern frequencies per study were analyzed using a random effects meta-analysis model. A thorough review of 45 records retrieved resulted in 4 articles meeting eligibility criteria, comprising 2182 subjects with OFC and 3171 controls. No TA (0.0.0.0) was seen in 51% of OFC cases and 97% of controls. TAC patterns 0.2.0.0, 2.0.0.0, and 2.2.0.0 indicating uni- or bi-lateral missing upper laterals, and 16.0.0.0 indicating missing upper right second premolar, were more common in subjects with OFC. Subjects with OFC have unique TA patterns and defining these patterns will help increase our understanding of the complex etiology underlying TA.

Subphenotypes in Non-Syndromic Orofacial Cleft Patients Based on the Tooth Agenesis Code (TAC).

Background: It was the aim of this study to investigate tooth agenesis patterns, which are expressed to different subphenotypes according to the TAC method in a spectrum of non-syndromic orofacial cleft patients. Methods: A total of 183 orofacial cleft patient records were assessed for tooth agenesis and TAC patterns. The association between TAC and sex, and cleft type was examined, and logistic regression models were additionally applied. Additionally, the distribution of missing teeth by cleft type and the tooth agenesis inter-quadrant association were examined. Results: The most frequent cleft type was CLPL (n = 72; 39.3%), while the maxillary left lateral incisor was the most frequently missing tooth that was strongly dependent on the cleft type (29.5%, p < 0.001). Of the 31 TAC patterns identified, four were the most prevalent and occurred in 80.8% of the sample, while 20 TAC patterns were unique. Cleft type contrary to sex (p = 0.405) was found to play a significant role in TAC distribution (p = 0.001). The logistic regression’s results suggested that overall, neither sex nor cleft type were associated with tooth agenesis. Prevalence of tooth agenesis in each quadrant clearly depended on cleft type; and there was a strong association found between tooth agenesis in different quadrants. Conclusions: Thirty-one different subphenotypes were identified in TAC patterns. The first four TAC patterns accounted for the 80.8% of the sample’s variability while twenty of the patterns were unique. A strong association was present between TAC pattern and cleft type. No association was found between the sex of the patient, tooth agenesis and TAC patterns. Tooth agenesis depended strongly on the cleft type, and the most frequently missing tooth was the maxillary left lateral incisor. The interquadrant association for tooth agenesis found suggests a genetic link in the etiology of clefts.

Sexual dimorphism in the consecutive tooth agenesis patterns of patients with non-syndromic oligodontia

ABSTRACT Purpose To compare consecutive tooth agenesis (CTA) patterns between female and male patients with non-syndromic oligodontia. Materials and Methods Panoramic radiographs of 311 orthodontic patients (194 females and 117 males) with non-syndromic oligodontia were evaluated, and permanent teeth excluding third molars were examined. The number and prevalence of tooth agenesis and the number of agenetic teeth associated with CTA were calculated for each tooth. Numbers of CTAs in each dental arch and per patient, and numbers of agenetic teeth associated with the longest CTA were evaluated and compared between the female and male patients. The CTA type of each dental arch was categorized as follows: (I) anterior teeth only; (II) posterior teeth only; (IIIA) continuously in anterior and posterior teeth; (IIIB) separated in anterior and posterior teeth; and (IV) multiple types. The types were then compared between the female and male patients. Results Male patients more frequently had at least one CTA than female patients. The prevalence of Types I and IIIA in the mandibular arch was significantly higher in males than in females. Conclusion Although there was no significant sex difference in the overall severity, males with non-syndromic oligodontia were more likely than females to have CTA indicating local severity in the mandibular anterior teeth.

Rare phenotype: Hand preaxial polydactyly associated with LRP6-related tooth agenesis in humans

Low-density lipoprotein receptor-related protein 6 (LRP6) is a pathogenic gene of selective tooth agenesis-7 (OMIM#616724). Although the malformation of the digits and fore- and hindlimbs has been reported in Lrp6-deficient mice, it has been rarely discovered in humans with LRP6 mutations. Here, we demonstrate an unreported autosomal dominant LRP6 heterozygous mutation (c.2840 T > C;p.Met947Thr) in a tooth agenesis family with hand polydactyly, and another unreported autosomal dominant LRP6 heterozygous mutation (c.1154 G > C;p.Arg385Pro) in a non-syndromic tooth agenesis family. Bioinformatic prediction demonstrated the deleterious effects of the mutations, and LRP6 structure changes suggested the corresponding functional impairments. Analysis on the pattern of LRP6-related tooth agenesis demonstrated the maxillary lateral incisor was the most affected. Our study report that LRP6 mutation might be associated with hand preaxial polydactyly in humans, which broaden the phenotypic spectrum of LRP6-related disorders, and provide valuable information on the characteristics of LRP6-related tooth agenesis.

PREMOLAR AGENESİS PREVALENCE AND PATTERNS IN A SAMPLE OF TURKISH CHILDREN

Objective: The aim of this study was to evaluate the characteristics of premolar tooth agenesis patterns in Turkish children and confirm a valid cutoff age.&#x0D; Methods: Included in this study were panoramic radiographs of 3637 Turkish pediatric patients aged 7–12 years (1819 males and 1818 females), whose panoramic radiographs were taken. . The prevalence of premolar hypodontia, sex distribution, distribution of premolar hypodontia in the maxilla and mandible, unilateral/bilateral incidences and cutoff ages were examined in radiographs.&#x0D; Results: The prevalence rate of agenesis of one or more premolars was 3.1% (n = 111) for both sexes combined, and 1.4% for boys and 1.6% for girls, with no significant difference between the sexes (p = 0.498). No significant difference was observed between younger and older groups at the cutoff ages examined&#x0D; Conclusion: An early diagnosis of premolar agenesis enables ideal and conservative treatment planning, which may involve less invasive treatment options for patients diagnosed in the early period. For these reasons, the awareness of dentists regarding these treatments should be enhanced. Therefore, there is a need for more studies regarding the prevalence of this condition, which will provide important clinical value in the timely diagnosis of hypodontia.

Prevalence and patterns of tooth agenesis among patients aged 12-22 years: A retrospective study.

ObjectiveThis study aimed to establish the prevalence and patterns of nonsyndromic tooth agenesis in patients referred to a tertiary health care facility.MethodsThe intraoral records and panoramic radiographs of 9,874 patients aged 12–22 years were evaluated. The study group included 716 patients (371 male, 345 female) with non-syndromic agenesis of at least one tooth (except the third molars). The study data were assessed using descriptive statistics, chi-square test, and Mann–Whitney U test, while patterns were evaluated using a tooth agenesis code (TAC) tool.ResultsA total of 1,627 congenitally missing teeth, were found in patients with non-syndromic tooth agenesis, with an average of 2.27 missing teeth per patient. The prevalence of tooth agenesis was 7.25%, and the most commonly missing teeth were the left mandibular second premolars (10.17%). The age group comparison revealed no significant difference in the median number of missing teeth per patient according to the cutoff values for ages between 12 and 22 years. When the missing teeth were examined separately according to quadrants, 114 different tooth agenesis patterns (upper right quadrant = 28, upper left quadrant = 27, lower left quadrant = 31, and lower right quadrant = 28) were identified, and 81 of these patterns appeared only once.ConclusionsThis study highlights the benefits of applying the TAC tool in a large sample population. The application of the TAC tool in such studies will enable the development of template treatment plans by determining homogenous patterns of tooth agenesis in certain populations.

Consecutive tooth agenesis patterns in non-syndromic oligodontia.

Agenesis of two or more consecutive adjacent permanent teeth (consecutive tooth agenesis, CTA) is a serious manifestation of oligodontia requiring long-term, multi-disciplinary treatment. Therefore, the present study investigated the characteristics of the CTA pattern in orthodontic patients with non-syndromic oligodontia. Using panoramic radiographs, the number of agenetic permanent teeth excluding third molars in non-syndromic orthodontic patients was evaluated, and patients with six or more agenetic teeth (oligodontia group, n = 97) and with one to five agenetic teeth (hypodontia group, n = 107) were selected. The numbers of CTA including third molars in each quadrant and in each patient were compared between the groups. Each quadrant with CTA of patients was categorized into one of the following four types: (I) involves anterior teeth only; (II) involves posterior teeth only; (IIIA) includes anterior and posterior teeth; and (IIIB) separate in the anterior and posterior teeth. CTA in at least one quadrant was found in 91.8 and 4.7% of patients in the oligodontia and hypodontia groups, respectively. The highest frequency CTA patterns included agenesis of the first and second premolars and of the second and third molars in the oligodontia and hypodontia groups, respectively. In the oligodontia group, type IIIA was significantly more frequent in the maxillary than in the mandibular quadrant. Most oligodontia patients who visit orthodontic clinics have CTA. A rare but severe CTA pattern that continues from the anterior to posterior segments is more frequent in the maxillary than in the mandibular quadrant.