Maxillary Hypodontia Research Articles

MON-257 Axenfeld Rieger Syndrome: An Uncommon Cause of Growth Hormone Deficiency

Axenfeld-Rieger syndrome (ARS) is an autosomal dominant disorder presenting with abnormal eye development, which leads to glaucoma related blindness in 50% of individuals. Associated mutations affect the transcription factors pituitary homeobox 2 gene (PITX2) and forkhead box C1 gene (FOXC1). Three types of ARS have been described. PITX2 mutation causes ARS type I, which is associated to systemic malformations, including dental hypoplasia, redundant periumbilical skin, and growth hormone deficiency (GHD).This is the case of a 28-year-old male diagnosed with GHD during childhood. He was referred to a pediatric-endocrinologist at age 10 due to short stature. Evaluation showed a height-for-age curve below the 10th percentile. Physical examination with prominent forehead, decrease visual acuity, maxillary hypodontia, umbilical hernia, and delayed sexual maturity. Testing with reduced IGF-1 and delayed bone age. Clonidine GH stimulation confirmed the diagnosis of GDH. He was treated with somatropin, until linear growth decreased to ½ inch per year at age 16. GHD etiology was never established. At age 26, he developed progressive decrease in visual acuity. Ophthalmology evaluation disclosed polycoria, megalocornea and increase intraocular pressure, suggestive of ARS. Patient was referred to our endocrinology clinics for follow up of previous diagnosis of GHD. Based on clinical findings and history, sequence analysis and deletion/duplication testing of FOXC1, PAX6 and PITx2 were performed, with results positive for pathogenic variant PITX2, Exon 5, c.363_364delinsAA. Assessment of pituitary hormone axis was normal, and no persistent GHD found. No family members exhibited clinical signs of ARS.Axenfeld-Rieger syndrome is a rare genetic disease. PITX homeodomain transcription factors are critical for the development of the anterior segment of the eye and pituitary. Most mutations in PITX2 affect DNA binding and transactivation that leads to defects in cell proliferation and differentiation of the Rathke’s pouch. As a result, GHD may ensue. ARS patients are usually diagnosed during childhood after the development of vision abnormalities. The diagnosis remains primarily clinical upon identification of ocular abnormalities in the iris and cornea, and increased intraocular pressure. Systemic changes are rare findings in ARS, but may include face and tooth abnormalities and isolated growth hormone deficiency. Genetic diagnosis is based on identification of mutations. An adequate management of ARS requires a multidisciplinary approach. Although ophthalmologists usually diagnose this condition, some patients initially present with isolated growth impairment. This may lead to a delay in ophthalmologic evaluation and management. Thus, in patients with GHD of unknown etiology, it is important to have a high index of suspicion of ARS in order to decrease morbidity from vision loss.

Dental and craniofacial anomalies associated with Axenfeld–Rieger syndrome

Axenfeld–Rieger syndrome (ARS) is a rare, autosomal dominant disorder with genetic and morphologic variability and characterized by ocular and nonocular clinical findings. Midface hypoplasia and maxillary hypodontia are classical presenting features of this syndrome. This case report describes a dental condition, immediate treatment required and a long-term treatment approach toward a patient 5-year-of-age with ARS, who presented with significant ocular and dental anomalies.

Associations between tooth agenesis and displaced maxillary canines: a cross-sectional radiographic study

BackgroundThe aim of present study was to test the association between hypodontia and displaced maxillary canine when compared with a control group.MethodsThe study group was composed of 336 subjects with a mean age of 10.7 ± 1.2 years, presenting with at least one missing tooth. Exclusion criteria included syndromes, craniofacial malformations, extractions and trauma history and previous orthodontic treatment. The control group consisted of 336 subjects with a mean age of 10.7 ± 1.2 years, without agenesis. Stepwise multiple logistic regression using the backwards elimination and the Wald test method was performed to identify the best combination of hypodontia and displaced maxillary canine (P < 0.05).ResultsThe most represented category in study group consisted in mild agenesis (86.9%); moderate and severe agenesis groups respectively represented the 11.7 and 1.4% of study group. Agenesis was diagnosed in both arches in 46 subjects. Maxillary hypodontia and mandibular hypodontia was respectively detected in 156 and 134 subjects. The most frequent missing teeth were mandibular second premolars (45.8%), lateral incisors (41.7%) and maxillary second premolars (17.8%). A significant correlation between agenesis and displaced maxillary canine was observed in the study group (P < 0.05). Only the agenesis of maxillary lateral incisors remained in the final model during backward stepwise deletion. Significant association between the severity of dental agenesis and prevalence of displaced maxillary canine was not assessed.ConclusionsThe outcomes revealed no difference related to the severity of dental agenesis and prevalence of displaced maxillary canine. Only the agenesis of maxillary lateral incisors should be considered directly connected with displaced maxillary canine.

Craniofacial characteristics of children with mild hypodontia.

The aim of our study was to evaluate the craniofacial characteristics of children with mild hypodontia using conventional and principal component (PC) analysis. We used radiographic images of 124 children (8-12years old) with up to 4 missing teeth (55 boys, 69 girls) and of 676 reference children (365 boys, 311 girls) from the Rotterdam Generation R Study and the Nijmegen Growth Study in The Netherlands. Fifteen cephalometric measurements of children with hypodontia were compared with those of the reference children. Moreover, cephalometric parameters were combined into standardized PC scores using PC analysis, and the components were compared between the 2 groups. PC analysisshowed common dental characteristics for all types of hypodontia: a significant increase of the interincisal angle, and decreases of the maxillary and mandibular incisor angles. Other findings were consistent when both methods were applied: (1) anterior hypodontia was significantly associated with the high-angle (hyperdivergent) craniofacial pattern, (2) the tendency toward a Class III malocclusion was identified in maxillary hypodontia, and (3) we observed a significant reduction of lower posterior facial height in children with posterior and mandibular hypodontia. Our findings suggest that children with mild hypodontia have distinctive skeletal and dental features.

Residents’ journal review

Residents’ journal review

Prevalence and patterns of permanent tooth agenesis in Down syndrome and their association with craniofacial morphology

To (1) document the prevalence and patterns of hypodontia (permanent tooth agenesis) in Down syndrome (DS) and (2) explore whether maxillary or mandibular hypodontia or simultaneous agenesis of all third molars was associated with differential alterations of the craniofacial morphology. Longitudinal panoramic radiographs of 25 white patients with DS (12 male, 13 female; mean age, 15.1 years) treated at The Hospital for Sick Children, Toronto, Ontario, Canada, were evaluated to document hypodontia. Cephalometric measurements of subjects with maxillary or mandibular hypodontia or agenesis of all third molars were compared with those of subjects without hypodontia in these regions using analysis of covariance adjusted for age, gender, and proportion of other missing teeth in the total number of missing teeth. Hypodontia was seen in 92% of the sample when third molars were considered and in 56% when third molars were not considered. Hypodontia was more prevalent and severe in females. The most frequently agenetic teeth were maxillary and mandibular third molars > maxillary lateral incisors > mandibular second premolars > mandibular incisors > maxillary second premolars > maxillary second molars. Simultaneous agenesis of all third molars was seen in 52% of the sample. Maxillary hypodontia was not associated with significant regional craniofacial differences, while mandibular hypodontia was associated with decreased mandibular length and increased ramus∶body ratio. Agenesis of all third molars was not associated with significant craniofacial differences. Hypodontia is widely prevalent in DS. The effect of the syndrome appears to be stronger than that of regional hypodontia in differentially altering the craniofacial morphology.

ARTICLE: Axenfeld-Rieger Syndrome (ARS): A review and case report

Axenfeld-Rieger syndrome (ARS) is a rare, autosomal dominant condition characterized by ocular, craniofacial, dental, and periumbilical abnormalities. Relatively little information exists on this syndrome within the dental literature despite the fact that midface hypoplasia and maxillary hypodontia are classical presenting features of this syndrome. This is a case report of a 7-year-old Caucasian female with ARS who presented with significant ocular and dental anomalies. She was also found to have osteopenia. Her dental condition is described, her immediate treatment is shown, and her long-term treatment needs are discussed.

Dysplasie ectodermique anhidrotique. Réhabilitation

Anhidrotic ectodermal dysplasia (EAD) is an inherited syndrome with an incidence of one per 100,000 live births and is characterized by hypotrichosis, anhidrosis or hypohidrosis, and oligodontia. Various treatment options for the dental rehabilitation of children presenting with this disease have been published. There is however no consensus on what age implants should be placed. Our purpose was to describe the disease and rehabilitation with early implants through two case reports. Our two patients, a brother and sister, aged 14 and 15 years respectively, presented with EAD, maxillary hypodontia, and mandibular anodontia. They benefited from an orthodontic surgical treatment followed by prosthetic treatment. We designed a removable prosthesis on mandibular implants for the boy when he was 14, which was later replaced by a fixed prosthesis on implants. We shifted the lateral maxillary incisors orthodontically to a canine position, then performed autologous bone grafting for the placement of six implants. The same bone graft technique was used for the sister to insert four maxillary implants. The follow-up after implant placement was 7 and 4years, respectively. On the latest follow-up, the results were stable, functional, and esthetic. Dental implants are a reliable oral rehabilitation treatment for children presenting with ectodermal dysplasia.