Putatively, tooth agenesis was attributed to the initiation failure of tooth germs, though little is known about the histological and molecular alterations. To address if constitutively active FGF signaling is associated with tooth agenesis, we activated Fgf8 in dental mesenchyme with Osr-cre knock-in allele in mice (Osr2-creKI; Rosa26R-Fgf8) and found incisor agenesis and molar microdontia. The cell survival assay showed tremendous apoptosis in both the Osr2-creKI; Rosa26R-Fgf8 incisor epithelium and mesenchyme, which initiated incisor regression from cap stage. In situ hybridization displayed vanished Shh transcription, and immunostaining exhibited reduced Runx2 expression and enlarged mesenchymal Lef1 domain in Osr2-creKI; Rosa26R-Fgf8 incisors, both of which were suggested to enhance apoptosis. In contrast, Osr2-creKI; Rosa26R-Fgf8 molar germs displayed mildly suppressed Shh transcription, and the increased expression of Ectodin, Runx2 and Lef1. Although mildly smaller than WT controls prenatally, the Osr2-creKI; Rosa26R-Fgf8 molar germs produced a miniature tooth with impaired mineralization after a 6-week sub-renal culture. Intriguingly, the implanted Osr2-creKI; Rosa26R-Fgf8 molar germs exhibited delayed odontoblast differentiation and accelerated ameloblast maturation. Collectively, the ectopically activated Fgf8 in dental mesenchyme caused incisor agenesis by triggering incisor regression and postnatal molar microdontia. Our findings reported tooth agenesis resulting from the regression from the early bell stage and implicated a correlation between tooth agenesis and microdontia.

Focal microdontia is a dental anomaly characterized by the presence of a single abnormally small anterior or posterior tooth. The objective of this article is to provide an updated review of the literature on the advanced restorative management of focal microdontia, and to document a clinical case where the reviewed advanced restorative approaches were applied to treat a young adult presenting with a non-syndromic asymmetrical focal microdontia.We conducted a preliminary examination of the existing literature on the advanced restorative management of focal microdontia. Additionally, we presented a minimally invasive approach to the treatment of an 18-year-old female patient with non-syndromic asymmetrical focal microdontia. The primary advantage of adhesive dentistry is that it can better preserve the structure of smaller teeth. A review of literature reveals a paucity of reports on localized microdontia in the maxillary anterior region of the mouth. However, novel minimally invasive restorative procedures satisfy patients\' aesthetic and functional preferences. Well-executed additive diagnostic wax-ups and intraoral mock-ups can serve as a permanent restoration blueprint, providing predictable results for focal dental anomalies in the aesthetic zone. In conclusion, the use of minimally invasive dental approaches in young patients with focal microdontia can result in long-term satisfactory aesthetic outcomes.

BACKGROUND: Mutations 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.
METHODS: This 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.
RESULTS: The 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.
CONCLUSIONS: Our 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.

Weyers acrofacial dysostosis (WAD) is a rare skeletal dysplasia, which is autosomal-dominant, and the clinical symptoms are presented as dental anomalies, polydactyly, nail dystrophy, and short physical stature. It is also termed \"Curry‑Hall syndrome\" and reported to be linked to genetic mutations mapped on chromosome 4p16, the region reported being commonly associated with a similar genetic syndrome, Ellis-van Creveld (EVC) syndrome. Most individuals with EVC have congenital heart abnormalities, most often atrial septal defects, unlike WAD. In this case, a 15‑year‑old girl presented with onychodystrophy and polydactyly observed in the hands and feet, microdontia, or agenesis of teeth, which were conical in shape, with a short stature. The patient had dystrophy of nails since birth, and physical growth in terms of height did not match the normal growth parameters with respect to age. The patient also had abnormal dentation with conical-shaped teeth, with the rest of the clinical presentations suggestive of WAD.

Restorative treatment of microdontia teeth is often considered as the final step of post-orthodontic treatment. Based on digital workflow, this clinical report presents pre-orthodontic reshaping of anterior teeth in the smile disharmony of a young patient using bilayering composite injection technique. Transparent silicone indexes for dentin and enamel fillings were fabricated from three-dimensional-printed models of the digital wax-up. This noninvasive, simple and straightforward injection technique was able to provide semipermanent reversible aesthetic restorations while awaiting for adulthood and definitive prosthodontic solution. Closure of diastemas before orthodontic treatment were carried out to restore functional contact point and to guide future teeth movements.

Pediatric esthetic dentistry is a sensitive technique, as children can be less cooperative; hence, minimal appointments are preferred. The most conservative treatment modality for anterior esthetic rehabilitation is using direct composite veneer restorations. In many instances, esthetic improvements using composite resin are the only possible option until the growth phase of the pediatric patient is complete. In this article, we present three different case scenarios in young teenagers with different treatment needs requiring esthetic restorations. The first case report is a patient with amelogenesis imperfecta, the second is with generalized spacing, and the third is with localized microdontia. All three patients were followed up for six months post direct composite veneering and were highly satisfied with their treatment outcomes, which boosted their self-confidence.

Sex 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.
One 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.
The 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).
We 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.

Treatment of pediatric patients with partial anodontia is a challenge requiring interdisciplinary approach. Growth period, reduced vertical dimension, microdontia, and unacceptable esthetics present difficulties at various stages of prosthetic rehabilitation. Congenital absence of teeth impairs the nutritional status of the growing child and causes a psychological setback. This article describes the prosthetic management of a patient suffering from partial anodontia done over a period of 10 years. Considering the age and psychological and financial requirements of the patient, removable and fixed prostheses were fabricated at different phases of the treatment. The ultimate aim was restoration of function, improvement of esthetics, and overall psychological upliftment of the patient which was achieved by maxillary metal ceramic bridge and mandibular implant retained hybrid prosthesis.

BACKGROUND:  Disturbances seen during tooth formation result in developmental dental anomalies presenting in the oral cavity. These anomalies manifest as discrepancies in the number, color, size, and shape of the teeth. These dental anomalies can either be acquired, congenital, or developmental. Their early detection and management are necessary as they affect aesthetics and occlusion. The study had the aim of gauging the prevalence of developmental anomalies in the permanent dentition of Indian subjects.
METHODS: A total of 1192 participants recruited from the institute for study purposes, comprising males and females, were examined clinically and radiographically, and their dental casts were also evaluated. These subjects were assessed for anomalies in position, structure, number, and/or shape. Anomalies in the position include transmigration, transportation, and/or ectopic position; anomalies in the structure, including dentinogenesis imperfecta or amelogenesis imperfecta; anomalies in number, including hyperdontia or hypodontia; and anomalies in shape, including peg laterals, taurodontism, fusion, dens evaginatus, talon cusp, and/or microdontia.
RESULTS: A statistically significant difference was seen in unilateral microdontia and dentinogenesis imperfecta between males and females, with attained p-values of 0.003 and 0.06, respectively. The results of the present study showed that 9.89% (n = 118) study subjects, whereas 1% (n = 12) study subjects had two dental anomalies in their permanent dentitions, with no subject presenting more than two dental anomalies, showing that various dental anomalies have a low prevalence in the Indian population.
CONCLUSIONS: The present study has led to the conclusion that the prevalence of dental anomalies is low in Indian subjects. However, these anomalies should be detected and treated early to prevent them from causing further complications.

To investigate the distribution of dental anomalies between non-syndromic orofacial cleft patients and their association with the cleft type and gender.
Retrospective cross-sectional study involving examination of intraoral dental records and radiographs.
300 non-syndromic orofacial cleft patients included (161 males and 139 females, mean age: 10.23 ± 2.3 years).
Variables analyzed: tooth agenesis, microdontia, and supernumerary teeth. Data analysis: Chi-square and Fisher\'s exact tests to investigate the correlation between dental anomalies, cleft type, and gender.
Agenesis occurred in 66% of the subjects, supernumerary teeth in 19.6%, and microdontia in 18.3%. In females with unilateral left cleft lip and palate (CLP), agenesis was significantly higher compared to males. Both genders presented significant agenesis of maxillary lateral incisors and right central incisor. Significant agenesis of central incisor, canine and second premolar on the upper left side and lower second premolars were observed only in males, with significant microdontia for maxillary lateral incisors and left central incisor. Significant agenesis of maxillary first premolars was seen only in females. Agenesis in maxillary quadrants was significant for patients with unilateral right and left CLP, and bilateral CLP. In mandibular quadrants, agenesis was substantially higher for patients with isolated CP.
Results suggest that tooth agenesis and microdontia might not be directly associated with the cleft area\'s anatomical irregularity but are affected by gender and other genetic factors that regulate the development of the anomaly and the orofacial clefting mutually.