Solitary median maxillary central incisor, short stature, choanal atresia/midnasal stenosis (SMMCI) syndrome

Use of an Orthodontic and Otolaryngological Approach in an Infant with Holoprosencephaly

Holoprosencephaly is a complex human brain malformation resulting from incomplete cleavage of the prosencephalon into both hemispheres. Congenital nasal pyriform aperture stenosis (CNPAS) is sometimes found in patients with mild forms of holoprosencephaly. Surgical treatment is required. Low-invasive surgical approaches involve balloon dilation of the pyriform opening. We present the case of an 8-day-old girl diagnosed with holoprosencephaly, CNPAS, and the presence of a solitary median maxillary central incisor. Once examined by neonatologist, geneticist, pneumologist, otolaryngologist, and pediatric dentist, a combined otolaryngological-orthodontic approach was used. The obstruction of the right nasal cavity was treated by widening the nasal cavities and stabilizing them with a balloon dilation technique. After surgery, the respiratory space was increased by applying a neonatal palatal expander plate (NPEP) considering the palatal deformity: ogival shaped, anterior vertex growth direction, reduction of transverse diameters. The NPEP promoted distraction of the median palatine suture and assisted the nasal dilation. Therefore, after the insertion of NPEP, the physiological sucking-swallowing mechanism was activated. In infants with CNPAS, NPEP can be useful to ensure the safe stability of nasal dilation. A multidisciplinary approach is fundamental. In our experience, the close collaboration between an otolaryngologist and orthodontist is essential for the management of the patient with CNPAS.

Solitary Median Maxillary Central Incisor Syndrome: A Case Report of a Unique Dental Anomaly

Solitary median maxillary central incisor (SMMCI) syndrome is complex and usually develops 35-38 days postconception during the intrauterine period. A noteworthy discovery is that just one central incisor in the maxillary alveolus, found exactly on the centerline, is present in both deciduous and permanent dentitions with other congenital anomalies. Around one in every 50,000 live babies exhibits this abnormality. This report describes the case of a 13-year-old female patient with SMMCI syndrome with a complaint about an unsightly appearance due to a single large upper front tooth. We underline the importance of increasing clinician awareness of SMMCI syndrome and the need for a multidisciplinary approach to its care.

Solitary Median Maxillary Central Incisor Syndrome: A Case Report

Aim

This report intends to present a case of solitary median maxillary central incisor syndrome (SMMCI) and its multidisciplinary team approach for diagnosis of other associated anomalies, with special emphasis on their management.

Background

Solitary median maxillary central incisor syndrome is a unique developmental condition characterized by only maxillary central incisor and a series of developmental defects, appearing as a syndrome. The appearance of a single incisor may take place due to the union of two incisor teeth or the absence of tooth germs. The mechanism of the fusion is still uncertain.

Case description

A 9-year-old female child reported with a chief complaint of pain in the right lower back tooth for the past 10 days. The presence of a single maxillary central incisor was an incidental finding. Then a detailed history and multidisciplinary evaluations revealed the diagnosis of SMMCI syndrome.

Conclusion

The effort in diagnosing and managing this syndrome had a strong impact on the child's life of which the parent was highly motivated and got a better understanding of associated problems of overall development.

Clinical significance

In SMMCI syndrome, the patient requires a multidisciplinary health team in order to improve their quality of life. It is of greater importance to diagnose the syndrome and treatment of these median line deformities.

How to cite this article

Balasubramanian S, Haridoss S, Swaminathan K. Solitary Median Maxillary Central Incisor Syndrome: A Case Report. Int J Clin Pediatr Dent 2022;15(4):458-461.

Solitary Median Maxillary Central Incisor Syndrome: An Exploration of the Pathogenic Mechanism

This study aimed to identify the genetic cause of one Chinese family with solitary median maxillary central incisor (SMMCI) and explore the relationship between genotype and its phenotype. One Chinese family with clinical diagnosis of SMMCI was collected. Single Nucleotide Polymorphism (SNP) array was performed and identified variation was confirmed by whole-genome sequencing (WGS). The reported chromosomal abnormalities and pathogenic genes in patients with SMMCI in literature were reviewed and summarized. The proband was an 8-year-old boy presenting a typical solitary median maxillary central incisor with a range of other phenotypic anomalies, including ptosis. SNP array revealed a 14.3 Mbp heterozygous deletion at chromosome 18p11.32-p11.21 in the proband but not in the unaffected parents. WGS further confirmed the identified deletion. 194 genes were involved in the chromosome region. Among them, 12 genes had been shown to be associated with diseases, including TGIF1, a reported SMMCI gene. The de novo 18p deletion resulted in SMMCI in the present study. Our results provide new genetic evidence that structural abnormality in chromosome 18p contributes to solitary median maxillary central incisor.

CT findings of congenital neonatal pyriform aperture stenosis

Congenital neonatal pyriform aperture stenosis (CNPAS) is a rare but potentially lethal condition that causes respiratory distress. The characteristic narrowing of the pyriform aperture along with other associated craniofacial dysmorphism is diagnosed using cross-sectional imaging such as computed tomography (CT) and magnetic resonance imaging. CT scan is the imaging of choice for confirming and characterizing CNPAS. Infants are obligate nasal breathers in the first 5 months of life. Hence, a high degree of clinical suspicion, prompt imaging diagnosis and adequate respiratory support is critical to help reduce the morbidity of this condition.

Orthodontic space closure in a young female patient with solitary median maxillary central incisor syndrome

A solitary median maxillary incisor can occur as a rare single dental anomaly or a symptom of the early-intrauterine developmental brain disorder of holoprosencephaly. The few published case reports about orthodontic treatment for this disorder have only described space opening for prosthodontic replacement of a central incisor. In contrast, the present patient was treated with extraction of the solitary median maxillary central incisor and orthodontic space closure with subsequent minimally invasive restorations in order to avoid looming esthetic or periodontal sequelae associated with any type of fixed bridgework or implant-borne crowns in the sensitive maxillary anterior area-which is especially indicated in young girls with a hyperdivergent growth pattern.

Single median maxillary central incisor syndrome and variant in SMO gene associated with SHH pathway

Solitary median maxillary central incisor syndrome (SMMCI) is a rare congenital oronasal-dental midline anomaly. The aim of this paper is a presentation of a patient with SMMCI without other visible dentofacial anomalies, with a potentially new molecular etiology consisting of a gene-gene reaction and conservative therapeutic approach to nasal obstruction. Potentially pathogenic variants in the SMO gene (p.Gly422Glu) and in P2RY13 gene (p.Trp205*) inherited from the probant's father, and in the PLD2 gene (p.Gln319fs), inherited from the mother were found. A multidisciplinary approach is necessary for the management of patients with SMMCI, including a genetic consultation with genetic tests.

Solitary median maxillary central incisor syndrome: A rare entity

Solitary median maxillary central incisor (SMMCI) syndrome is a complex disorder and a rare dental anomaly, which is estimated to occur in approximately 1:50,000 live births. It is a unique developmental abnormality which involves the central incisor tooth germs, occurring with or without systemic involvement; hence, its early diagnosis is of great importance. The objective of this study was to discuss a case of SMMCI syndrome and various dental treatment alternatives available in management of such cases. Due to the possible association of this syndrome with other developmental problems, an early diagnosis and management becomes important. Moreover, when it is associated with other developmental malformation and defects, the management becomes multidisciplinary.

Solitary Median Maxillary Central Incisor due to Nasal Pyriform Aperture Stenosis in Fetus: The First Prenatal Ultrasound Case Report

Background

The single median incisor is a rare dental abnormality that could be isolated or could be part of many different syndromes or syndromic association with poor prognosis.

Case description

We report the first prenatal ultrasound description of a 31-year-old patient, gravida 1, para 0, whose male fetus was diagnosed at 25 weeks’ gestation with a single median incisor suggestive of nasal pyriform aperture stenosis in Montpellier University Hospital (France). A fetal magnetic resonance imaging (MRI) performed at 30 weeks’ gestation retrieved no intracranial midline cerebral anomalies and confirm nasal pyriform aperture stenosis suspicion. Amniocentesis, performed at 31 weeks, found a normal fetal karyotype (46XY) and a normal comparative genomic hybridization (CGH) array. After term vaginal delivery, clinical and radiological examination confirmed the diagnosis of an isolated single median maxillary central incisor linked to nasal pyriform aperture stenosis.

Conclusion

Prenatal diagnosis of a single median incisor due to nasal pyriform aperture stenosis is feasible and enables close postnatal follow-up.

How to cite this article

Fuchs F, Chadelle M, Captier G, et al. Solitary Median Maxillary Central Incisor due to Nasal Pyriform Aperture Stenosis in Fetus: The First Prenatal Ultrasound Case Report. Int J Clin Pediatr Dent 2020;13(3):295–298.

Clinical Evaluation of Solitary Median Maxillary Central Incisor Syndrome

Solitary median maxillary central incisor (SMMCI) is a rare dental anomaly. It is estimated to occur in 1 : 50,000 live births. The SMMCI tooth differs from the normal central incisor in that the crown form is symmetric and it develops and erupts precisely in the midline of the maxillary dental arch in both primary and permanent dentitions. The presence of SMMCI with hemifacial microsomia (HFM) is a very rare clinical condition. We report a case of SMMCI in a female of African ethnic origin, who presented with SMMCI in permanent dentition with mild nasal stenosis. An early diagnosis of SMMCI is important, since it may be a sign for other severe congenital or developmental abnormalities. Therefore, systematic follow-up and close monitoring of the growth and development of SMMCI patients are crucial.

The solitary median maxillary central incisor (SMMCI) syndrome: Associations, prenatal diagnosis, and outcomes

Solitary median maxillary central incisor (SMMCI) syndrome is a complex disorder consisting of multiple, developmental defects involving midline structures of the head, which includes the cranial bones, the maxilla, and its container dentition (specifically the central incisor tooth germ), together with other midline structures of the body. SMMCI may appear as an isolated trait or in association with other midline developmental anomalies. We describe the case of a patient with SMMCI. He presented with a solitary median maxillary incisor, short stature, corpus callosum anomalies and a microform of holoprosencephaly (HPE), diabetes insipidus, and neurodevelopmental delay. The diagnosis was performed postnatally based on clinical features, radiological imaging, and a comprehensive genetic study. SMMCI can be diagnosed during the prenatal or neonatal periods or during infancy. Evaluation of the superior maxillary bone is important for prenatal diagnosis. Direct evaluation through bidimensional ultrasound or the use of multiplanar ultrasound or tridimensional reconstruction should be performed in cases of brain or face malformations. Early diagnosis can contribute to improved prenatal assessment and postnatal management.

Choanal atresia and stenosis: Development and diseases of the nasal cavity

Proper craniofacial development in vertebrates depends on growth and fusion of the facial processes during embryogenesis. Failure of any step in this process could lead to craniofacial anomalies such as facial clefting, which has been well studied with regard to its molecular etiology and cellular pathogenesis. Nasal cavity invagination is also a critical event in proper craniofacial development, and is required for the formation of a functional nasal cavity and airway. The nasal cavity must connect the nasopharynx with the primitive choanae to complete an airway from the nostril to the nasopharynx. In contrast to orofacial clefts, defects in nasal cavity and airway formation, such as choanal atresia (CA), in which the connection between the nasal airway and nasopharynx is physically blocked, have largely been understudied. This is also true for a narrowed connection between the nasal cavity and the nasopharynx, which is known as choanal stenosis (CS). CA occurs in approximately 1 in 5,000 live births, and can present in isolation but typically arises as part of a syndrome. Despite the fact that CA and CS usually require immediate intervention, and substantially affect the quality of life of affected individuals, the etiology and pathogenesis of CA and CS have remained elusive. In this review I focus on the process of nasal cavity development with respect to forming a functional airway and discuss the cellular behavior and molecular networks governing this process. Additionally, the etiology of human CA is discussed using examples of disorders which involve CA or CS. This article is categorized under: Signaling Pathways > Cell Fate Signaling Comparative Development and Evolution > Model Systems Birth Defects > Craniofacial and Nervous System Anomalies.

Congenital midnasal stenosis - A novel technique for management

Neonates are obligate nasal breathers and nasal obstruction in a neonate is an emergency. Here we report two cases of congenital mid-nasal stenosis, discuss its presentation and diagnosis with description of a novel method of management.

The natural course of congenital nasal pyriform aperture stenosis

OBJECTIVES/HYPOTHESIS

Patients with congenital nasal pyriform aperture stenosis (CNPAS) may become less symptomatic with age. Therefore, we aimed to develop a growth curve of the pyriform aperture so that a more comprehensive plan can be designed for CNPAS patients who show little response to conservative treatment.

STUDY DESIGN

A single-institution study, retrospective review of CNPAS patients during the period November 1997 to December 2014.

METHODS

We measured the distances between the bilateral nasal processes of the maxilla (interprocess distance [IPD]) on three-dimensional computed tomography images and then divided the patients into five different age groups. A growth curve of the pyriform aperture was then constructed based on the distance-age relationship.

RESULTS

Fifty-four IPD measurements were included. The mean IPD was 3.57 mm in neonates < 1 month old, 4.08 mm in infants aged 1 to 3 months, 5.19 mm in the 4-month to 11-month age group, 6.61 mm in the 12-month to 36-month age group, and 9.20 mm in children > 36 months of age. We found that the cubic curve was the most appropriate growth curve, and that growth tended to be slower from 3.5 years to 6 years of age.

CONCLUSIONS

The growth curve of the pyriform aperture in children with CNPAS developed in this study can aid in treatment planning and predict clinical outcome of CNPAS patients. Although CNPAS patients may become less symptomatic with age, when the observed IPD falls progressively farther from the curve, more aggressive intervention should be considered, such as changing the management strategy from observation to conservative treatment or from conservative treatment to surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 126:2399-2402, 2016.

Two patients with small chromosome 22q11.21 alterations and central nervous system abnormalities

BACKGROUND

Central nervous system features have been rarely described to be associated with the small deletion or duplication of chromosome 22q11.21.

CASE PRESENTATION

We report two patients with chromosome 22q11.21 alterations and central nervous system abnormalities. Features described include semilobar holoprosencephaly in the patient with the small deletion and Chiari I malformation in the patient with the small duplication.

CONCLUSIONS

This report will aid in the characterization of the clinical significance of interstitial duplications and deletions on the long-arm of chromosome 22. Areas of future research would benefit from additional analysis of the described regions with inclusion of the phenotypic findings described in this case report to provide additional insight into the pathogenicity of the described alterations.

Genotypic and phenotypic variation in six patients with solitary median maxillary central incisor syndrome

Solitary Median Maxillary Central Incisor occurs in 1 of 50,000 live births. It is the mildest manifestation of the holoprosencephaly spectrum and is genetically heterogeneous. Here we report six patients with solitary median maxillary central incisor, and a range of other phenotypic anomalies with different degrees of severity, varying from mild signs of holoprosencephaly to associated intellectual disability, and with different genetic background. Using array comparative genomic hybridization, pathogenic copy number variants were found in three of the six patients. Two patients had a deletion at the 18p11 chromosomal region that includes TGIF1 while the other patient had a deletion at 7q36, including the SHH gene. In one patient, a mutation in SIX3 was detected with exome sequencing, while in the two remaining patients all known holoprosencephaly genes were excluded using multiplex ligation-dependent probe amplification and sequencing, and remain unsolved. One of the two latter patients had isolated solitary median maxillary central incisor without other visible dentofacial anomalies, while the other had clinical features not part of the known holoprosencephaly spectrum.

Solitary median maxillary central incisor: A case report of a rare dental anomaly

The solitary median maxillary central incisor (SMMCI) syndrome is a rare dental anomaly and has an incidence of 1:50,000 live births. In SMMCI, there is only one central incisor present, and it develops exactly at the midline. SMMCI occurrence has been described with growth hormone deficiency or other structural anomalies in the midline of the body. In this case, the 8-year-old female patient reported a single median maxillary central incisor with missing maxillary and mandibular frena, with apparently no other abnormalities. Early diagnosis and recognition of SMMCI are important for all practicing Orthodontists, as it may be a sign of other severe congenital or developmental abnormalities.

Premolar transplantation in a patient with solitary median maxillary central incisor syndrome

This case report describes the orthodontic treatment of an 11-year-old girl with solitary median maxillary central incisor syndrome, a presumed microform of holoprosencephaly. Because both second premolars were missing in the maxilla, deciduous molar extraction and orthodontic space opening were performed, moving the solitary median maxillary central incisor electively off-center. A mandibular second premolar was transplanted to replace the missing incisor. The resulting spaces could be orthodontically closed in both arches. Prosthodontic reshaping of the transplanted tooth after debonding completed the dental treatment.

Clinical course and implications of congenital nasal pyriform stenosis and solitary median maxillary central incisor in a newborn: a case report

Introduction

Congenital nasal pyriform aperture stenosis and solitary median maxillary central incisor are uncommon anomalies and are associated with further malformations. Solitary median maxillary central incisor itself has initially no impact on a child’s health, but congenital nasal pyriform aperture stenosis is a potentially life-threatening condition.

Case presentation

A Caucasian baby boy showed severe dyspnoea and was intubated orotracheally. Multiple anomalies were detected, including urogenital and craniofacial malformations. Computed tomography scans revealed congenital nasal pyriform aperture stenosis with a diameter of 4.9mm and a solitary median maxillary central incisor. A 3.0mm tube was inserted in his left nasal cavity, and the baby was able to breathe sufficiently and spontaneously. The nasal tube was removed after seven days, and the baby was discharged under application of decongestant drops. After seven months, the baby was readmitted with respiratory distress, and surgery was carried out using an intraoral sublabial approach. The stenotic area of the pyriform aperture was widened, and 3.0mm tubes were inserted in both nasal cavities for 10 days. Over a period of six months, no further respiratory distress has occurred.

Conclusions

The decision to perform surgery was delayed since the baby’s nasal breathing was adequate as a result of the insertion of a nasal tube. Since treatment depends on the severity of symptoms, it is appropriate in some cases to take a conservative approach at first, and to keep surgery as a last resort. Once a conservative approach has been selected for congenital nasal pyriform aperture stenosis, awareness of the life-threatening nature of the condition should be kept in mind, and a surgical approach must still be taken into account.

Developmental disorders of the dentition: an update

Dental anomalies are common congenital malformations that can occur either as isolated findings or as part of a syndrome. This review focuses on genetic causes of abnormal tooth development and the implications of these abnormalities for clinical care. As an introduction, we describe general insights into the genetics of tooth development obtained from mouse and zebrafish models. This is followed by a discussion of isolated as well as syndromic tooth agenesis, including Van der Woude syndrome (VWS), ectodermal dysplasias (EDs), oral-facial-digital (OFD) syndrome type I, Rieger syndrome, holoprosencephaly, and tooth anomalies associated with cleft lip and palate. Next, we review delayed formation and eruption of teeth, as well as abnormalities in tooth size, shape, and form. Finally, isolated and syndromic causes of supernumerary teeth are considered, including cleidocranial dysplasia and Gardner syndrome.

Solitary median maxillary central incisor syndrome (SMMCI) with congenital nasal puriform aperture stenosis: literature review and case report with comprehensive dental treatment and 14 years follow-up

BACKGROUND

Solitary median maxillary central incisor syndrome [SMMCI] is an extremely rare anomaly, especially when no other abnormalities are present. The defect is often found together with various nasal abnormalities and short stature with or without decreased levels of growth hormone. In more severe cases, SMMCI has been associated with holoprosencephaly, the CHARGE and the VACTERL association. Also, published sporadic cases have been related with rare variants of ectodermal dysplasia, chromosomal abnormalities, precocious puberty, hypothalamic hamartoma, congenital heart defects, physical/mental retardation, genital hypoplasia and ear abnormalities. For these reasons when the initial diagnosis is made by the paediatric dentist, ENT, neurological and paediatric evaluations are essential.

CASE REPORT

A 4-year-old boy with SMMCI was referred for dental treatment. Clinical/radiographic examination revealed a symmetrical primary and permanent SMMCI, a skeletal Class I and a unilateral crossbite. Medical history indicated respiratory distress and surgery soon after birth due to congenital nasal puriform aperture stenosis. Gradual orthodontic treatment started at the age of 4 years and completed at the age of 13 years. Following maxillary expansion, upper lateral segments were moved backwards and anterior space was created for accommodating a second central incisor. Retainers with a supplementary acrylic incisor were provided for aesthetic and functional replacement until the age of 16 years, when a fixed Maryland ceramic bridge was placed.

FOLLOW-UP

Two years recall, at the age of 18 years, revealed a satisfactory and stable aesthetic and functional result.

CONCLUSION

Successful dental management of SMMCI patients is possible, following a detailed long-lasting treatment plan requiring multidisciplinary paediatric dental, orthodontic and prosthetic approach.

Concomitant solitary median maxillary central incisor and fused right mandibular incisor in primary dentition

Solitary median maxillary central incisor (SMMCI) is a unique developmental anomaly in primary dentition. It involves central incisor tooth germs and may or may not be associated with other anomalies. Its presence, concomitant with fusion of right mandibular incisors has not previously been reported. A 5-year-old girl was presented with a single symmetrical primary maxillary incisor at the midline, with the absence of labial frenulum, an indistinct philtrum and a prominent midpalatal ridge. There was an associated fused tooth in the right incisor region and radiographic examination confirmed only one maxillary central incisor in both the dentitions. Family history revealed that the father of the girl also had a similar anomaly providing probable evidence of etiological role for heredity in SMMCI.

Dental development and tooth agenesis in children with velocardiofacial syndrome

BACKGROUND. Variations in dental development and tooth agenesis have been reported in children with velocardiofacial syndrome (VCFS). AIM. The aim was to evaluate the dental development and missing permanent teeth in children with VCFS. DESIGN. Forty-five children (23 girls) with VCFS who had visited the cleft palate and craniofacial centre were studied retrospectively from orthopantomograms taken at the mean age of 7.9 years (range 5.8-12.9). Thirteen of the children with VCFS had palatal clefts. The deletion of 22q11 was verified by FISH techniques. The dental stages were assessed by the method of Demirjian, and the dental age was calculated according to the Finnish dental maturity reference values. A paired Student's t-test was used in the statistical analysis. RESULTS. Eight children (17%), four with palatal clefts, had tooth agenesis. Four children (9%) had agenesis of mandibular incisors. The missing teeth (n = 19) were mainly mandibular incisors (n = 6), maxillary lateral incisors (n = 2), and maxillary second premolars (n = 4). The dental age of the children with VCFS was not different from their chronological age, but there was great individual variation. CONCLUSIONS. A high prevalence of missing permanent teeth, especially mandibular incisors, was observed. The need for thorough clinical and radiological dental examination in children with VCFS is emphasized.

Solitary median maxillary central incisor in association with hemifacial microsomia: A rare case report and review of literature

Solitary median maxillary central incisor (SMMCI) is a rare dental anomaly. It is estimated to occur in 1:50,000 live births. The SMMCI tooth differs from the normal central incisor in that the crown form is symmetric and it develops and erupts precisely in the midline of the maxillary dental arch in both primary and permanent dentitions. Presence of SMMCI with hemifacial microsomia (HFM) is a very rare clinical condition. We report a case of HFM in a male of Indian origin who presented with SMMCI in both primary and permanent dentitions. The association of HFM with SMMCI may be due to defective development of neural crest cells and/or lack of space in maxilla.

Solitary median maxillary central incisor and congenital nasal pyriform aperture stenosis combined with asymmetric crying facies and postaxial lower limb reduction defects: a unique combination of features

We report a boy with asymmetric crying facies and bilateral absence of the 5th ray of the feet. In addition, craniofacial computed tomography showed a solitary median maxillary central incisor in combination with a narrow apertura piriformis. To our knowledge this intriguing combination of congenital abnormalities has not been described before.

Palatal expansion in a patient with solitary median maxillary central incisor syndrome

The objective of this article was to report a clinical case of a patient with solitary median maxillary central incisor syndrome. He was treated with rapid maxillary expansion and evaluated with computed tomography. The boy, aged 6 years 7 months, had a single maxillary central incisor in the midline, posterior crossbite, prominent midpalatal ridge, indistinct philtrum, no incisive papilla, and no labial frenulum. No other systemic anomalies were found. Posteroanterior cephalometric radiography showed skeletal atresia of the maxilla that was corrected with rapid maxillary expansion. A Haas expander was used and activated twice per day (quarter turn per activation) for 15 days. The procedure was monitored with computed tomography to evaluate any effect on the intermaxillary suture and tooth. Although the crossbite was clinically corrected after the expansion, radiographs and tomographs showed no opening of the midpalatal suture. Rapid maxillary expansion resulted in neither midpalatal suture opening nor transverse increase of the maxillary skeletal base in this patient.

The morphology of the sella turcica in velocardiofacial syndrome suggests involvement of a neural crest developmental field

We described the morphology of the sella turcica in individuals with velocardiofacial syndrome (VCFS), also known as chromosome 22q11.2 deletion syndrome, and compared the morphology with that of a control group of individuals from the Oslo University Craniofacial Growth Archive. The aim was to measure the cranial base angles in individuals with VCFS and, if possible, to discover the developmental field that may be involved in the condition. The study included 33 patients with VCFS from the Copenhagen Cleft Palate Center, Denmark. The genotype was confirmed by fluorescence in situ hybridization. The morphology of the sella turcica was described and measurements of the cranial base angles were performed on lateral cephalometric radiographs. The VCFS individuals had larger deviations in the morphology of the sella turcica compared to individuals from the Oslo University Craniofacial Growth archive. The deviations were mostly in the posterior part of the dorsum sellae. Individuals with VCFS had increased cranial base angles. The results of this study combined with the information in the literature on the main defects in VCFS (palatal abnormalities, cardiac anomalies, thymic hypoplasia or aplasia, hypothyroidism, and posterior brain abnormality), suggest involvement of a specific developmental field.

A case of solitary median maxillary central incisor (SMMCI) syndrome with bilateral pyriform aperture stenosis and choanal atresia

Solitary median maxillary central incisor syndrome is a rare disorder involving midline abnormalities. It may present with life threatening respiratory distress in the neonate secondary to nasal malformations. These include pyriform aperture stenosis and choanal atresia. We present the first reported case of simultaneous choanal atresia and pyriform aperture stenosis in a neonate with solitary median maxillary central incisor syndrome. The clinical presentation and the management of congenital pyriform aperture stenosis are discussed.

Síndrome do incisivo central superior solitário: relato de caso

INTRODUÇÃO: a presença de um incisivo central superior solitário é um evento bastante incomum na população. A prevalência da chamada Síndrome do Incisivo Central Superior Solitário (SICSS) é verificada em 1:50.000 nascimentos, sendo registrado um maior acometimento no sexo feminino. Essa alteração no desenvolvimento da oclusão dentária é caracterizada por más formações estruturais, sobretudo na região de linha média do paciente. O diagnóstico precoce e o tratamento adequado dessa síndrome são de grande importância, pois essa condição talvez seja um indicativo de que o paciente pode apresentar outras más formações congênitas severas, não devendo ser a SICSS considerada uma simples anomalia dentária. Os procedimentos ortodônticos, nesses casos, variam dependendo do grau de comprometimento das estruturas ósseas da maxila, da oclusão em si, e principalmente da sutura palatina mediana. OBJETIVO: discutir, baseado em evidências científicas, aspectos importantes relacionados à SICSS, bem como apresentar um caso clínico de paciente do sexo feminino com SICSS, que foi submetida a tratamento ortodôntico na Clínica Odontológica Integrada Infantil da Universidade Federal de Santa Maria / RS. CONCLUSÃO: pela análise crítica da literatura, verifica-se ser muito importante o diagnóstico correto e precoce acerca dessa síndrome, visto que há possibilidade da mesma estar associada a outros problemas de desenvolvimento. Além disso, o paciente acometido pela SICSS deve ser assistido por uma equipe multidisciplinar de saúde, de forma a otimizar os resultados clínicos e devolver-lhe qualidade de vida.

Solitary median maxillary central incisor syndrome occurring together with oromandibular-limb hypogenesis syndrome type 1: a case report of this previously unreported combination of syndromes

BACKGROUND

Solitary median maxillary central incisor syndrome is a unique developmental abnormality, involving the central incisor tooth germs, occurring with and without systemic involvement. This syndrome has been recorded in association with many other midline developmental anomalies and several known syndromes. Its presence, together with oromandibular-limb hypogenesis syndrome type 1, has not previously been reported.

CASE REPORT

A 3-year-old girl was presented with early childhood caries and a solitary median maxillary central incisor. She had a median submucosal cleft palate and severe micrognathia with hypoglossia. In addition, she had short stature, eating difficulty, and hearing and speech problems. Comprehensive dental treatment for severe early childhood caries was accomplished with a 3-month follow-up appointment to monitor the oral health. The multidisciplinary consultation important for further management has been established.

CONCLUSION

The results suggested that when a solitary median maxillary incisor tooth presents, a paediatrician and a geneticist should be asked to carefully examine the patient for other craniofacial malformations and especially midline systemic problems.

Beware the solitary maxillary median central incisor

The incidence of a solitary maxillary median central incisor (SMMCI) tooth in the general population is low, in either the primary or secondary dentition. The most common cause of a missing maxillary central incisor is trauma, or more rarely hypodontia. However, SMMCI is also a recognized genetic anomaly and affected individuals can be carriers for a potentially more serious condition affecting midline development of the brain and face, holoprosencephaly (HPE). The presence of an SMMCI of unknown aetiology is therefore considered a risk factor for HPE, even in the absence of any other clinical signs. The orthodontist may be responsible for diagnosing cases of SMMCI with no obvious cause, and in these subjects due consideration should be given to referral for the appropriate genetic testing and counselling.

Single median maxillary central incisor: new data and mutation review

BACKGROUND

Single median maxillary central incisor (SMMCI) is a rare anomaly that may occur alone or associated with other conditions, frequently as part of the holoprosencephaly (HPE) spectrum. However, it has been suggested that SMMCI alone, or associated with some midline defects, may be considered a different entity from HPE (OMIM: 147250). Families with SMMCI, without HPE cases, are difficult to counsel for the risk of HPE in future generations because the same midline defects described as part of the "SMMCI syndrome" can also be part of the HPE spectrum.

METHODS

We screened five cases of SMMCI for mutations in three HPE genes, SHH, TGIF, and SIX3.

RESULTS

A missense mutation c.686C>T was found in the gene SIX3 of one patient, which did not differ from the accepted 20% of known HPE gene mutations among all HPE cases. Our results and an extensive literature review of gene mutations in patients with SMMCI showed that 27/28 of them were in HPE genes: SHH (n = 21), SIX3 (n = 3), TGIF (n = 1), GLI2 (n = 1), and PTCH (n = 1), and only one in the SALL4 gene.

CONCLUSIONS

The clinical findings in patients with SMMCI without HPE in families with mutations in HPE genes cannot be distinguished from the findings reported in the SMMCI syndrome. Therefore, persons with SMMCI and their relatives should be carefully investigated for related midline disorders, especially of the HPE spectrum, and all known HPE genes screened.

Solitary median maxillary central incisor in association with Goldenhar's syndrome: a case report

Goldenhar's syndrome is a rare disorder characterized by several anomalies that include dermal epibulbar cysts, auricular appendices and malformations and vertebral anomalies. In this article, the authors report a case of Goldenhar's syndrome in a 10-year-old child who presented with the classical signs of this condition and a solitary median maxillary central incisor (SMMCI).

A new technique for symmetry determination in tooth morphology using image analysis: Application in the diagnosis of solitary maxillary median central incisor

OBJECTIVE

To develop a new technique for determining symmetry in tooth morphology and to evaluate this in the investigation of a patient with a solitary maxillary median central incisor (SMMCI) and a control group.

DESIGN

A 9-year-old Caucasian female presented with SMMCI. Clinically the tooth appeared symmetrical. Morphology measurements of the maxillary central incisor were made using an image analysis system. Symmetry was determined by outlining the tooth from labial and axial views. These images were block filled, duplicated, flipped horizontally and then superimposed on the original image. The coincident area and perimeter of the two images from both views were measured. The method was repeated for the maxillary central incisors of 20 sets of control study models for young adult patients from which reference intervals for comparison with the SMMCI case were prepared.

RESULTS

From the labial view, the area and perimeter of the two images of the SMMCI tooth were 98.85% and 98.97% coincident, respectively. From the axial view the area of the two images was 96.17% coincident, while the perimeter was 99.03% coincident. In all but one comparison for coincidence the SMMCI was above the upper limit of the reference range from the control group.

CONCLUSIONS

This new technique is a valid method of assessing symmetry and is a useful clinical tool in cases of SMMCI.

Solitary median maxillary central incisor (SMMCI) syndrome

Solitary median maxillary central incisor syndrome (SMMCI) is a complex disorder consisting of multiple, mainly midline defects of development resulting from unknown factor(s) operating in utero about the 35th-38th day(s) from conception. It is estimated to occur in 1:50,000 live births. Aetiology is uncertain. Missense mutation in the SHH gene (I111F) at 7q36 may be associated with SMMCI. The SMMCI tooth differs from the normal central incisor, in that the crown form is symmetric; it develops and erupts precisely in the midline of the maxillary dental arch in both primary and permanent dentitions. Congenital nasal malformation (choanal atresia, midnasal stenosis or congenital pyriform aperture stenosis) is positively associated with SMMCI. The presence of an SMMCI tooth can predict associated anomalies and in particular the serious anomaly holoprosencephaly. Common congenital anomalies associated with SMMCI are: severe to mild intellectual disability, congenital heart disease, cleft lip and/or palate and less frequently, microcephaly, hypopituitarism, hypotelorism, convergent strabismus, oesophageal and duodenal atresia, cervical hemivertebrae, cervical dermoid, hypothyroidism, scoliosis, absent kidney, micropenis and ambiguous genitalia. Short stature is present in half the children. Diagnosis should be made by eight months of age, but can be made at birth and even prenatally at 18-22 weeks from the routine mid-trimester ultrasound scan. Management depends upon the individual anomalies present. Choanal stenosis requires emergency surgical treatment. Short stature may require growth hormone therapy. SMMCI tooth itself is mainly an aesthetic problem, which is ideally managed by combined orthodontic, prosthodontic and oral surgical treatment; alternatively, it can be left untreated.

Solitary median maxillary central incisor and normal stature: a report of three cases

Solitary median maxillary central incisor (SMMCI) is a rare finding. Growth deficiency or other systemic abnormalities may or may not be seen in children with this anomaly. Nevertheless, the growth and development of all children with SMMCI should be closely monitored. This article reports the dental findings of three Chinese girls with SMMCI, but no growth deficiency or other systemic involvement.

Velocardiofacial syndrome with single central incisor

Three siblings and their mother are reported who all had cytogenetically proven velocardiofacial syndrome (VCFS). One boy had normal dental and craniofacial findings, except for an increased cranial base angle. His sister had only one central incisor in the maxilla. One central incisor had also been missing in the primary dentition. She had no labial frenulum present. Cephalometry showed a small maxillary unit length indicating mild maxillary hypoplasia, an increased anterior face height, steep mandibular plane angle, retruded chin, and a large cranial base angle. Dental measurements showed retroclined lower incisors and increased interincisal angle. A second sister had a cleft of the secondary palate. All permanent teeth were present with the exception of a missing central incisor in the lower jaw: the single lower central incisor was situated in the midline. Her cephalometry showed similar findings as in her sister. All three siblings required palate surgery for speech. Mother was not available for detailed dental and other oral investigations. A single maxillary central incisor has previously been reported in VCFS, but to our knowledge a single central incisor in the mandible has not been reported previously in this entity.

Anatomical consideration of the congenital nasal pyriform aperture stenosis: localized dysostosis without interorbital hypoplasia

Congenital nasal pyriform aperture stenosis may be isolated or associated with other midline anomalies. The aim of the study was to describe the measurements and features of the interorbital structure and midface in congenital nasal pyriform aperture stenosis. The computed tomography scans of eight patients (two girls and six boys) were retrospectively reviewed. Several distances were obtained at the orbital and midface levels and compared with normative data. The average width of the pyriform aperture was 5.5 mm +/- 1.6, and there was overgrowth of the pyriform aperture rim (nasal process of the maxilla). No skeletal anomalies were present other than the congenital nasal pyriform aperture stenosis. It was associated with a single median maxillary central incisor in two cases. The anterior and lateral interorbital distances were normal (17.4 mm and 65.4 mm, respectively). The midface was not hypoplastic. There was no brain malformation. Congenital nasal pyriform aperture stenosis is a localized dysostosis of the pyriform aperture rim without interorbital or midface hypoplasia. It may be associated with a single median maxillary central incisor but cannot be viewed as a minor form of holoprosencephaly.

Solitary median maxillary central incisor, Duane retraction syndrome, growth hormone deficiency and duplicated thumb phalanx: a case report

A 4-year-old Italian child with the association of a solitary median maxillary central incisor, growth hormone deficiency, Duane retraction syndrome and a duplicated thumb phalanx is described.

Eruption of the central incisor, the intermaxillary suture, and maxillary growth in patients with a single median maxillary central incisor

The occurrence of a single median maxillary central incisor (SMMCI) is a very rare condition and might be a sign of a more severe midline defect, which could be a mild degree of holoprosencephaly. Absence of the internasal and partial absence of the intermaxillary suture has been observed in a fetus with holoprosencephaly. The purpose of this study was to evaluate the intermaxillary suture, the eruption pattern of the single central incisor in the SMMCI condition, and the growth of the maxilla in a group of patients with SMMCI. A similar study was not found in the scientific literature. The material included orthopantomographs, dental radiographs, and lateral cephalometric radiographs from 11 patients with an SMMCI. The orthopantomographs and dental radiographs showed that the intermaxillary suture was abnormal anterior to the incisive foramen; however, the SMMCI erupted within the expected time interval. Superimposition on stable structures on lateral cephalometric radiographs from two untreated patients, in which growth analysis was possible, showed that the horizontal and vertical growth of the maxilla was normal. Due to the sutural midline defect it is suggested that a transversal growth analysis is included in all treatment planning of SMMCI patients.

SHH mutation is associated with solitary median maxillary central incisor: a study of 13 patients and review of the literature

Solitary median maxillary central incisor (SMMCI) or single central incisor is a rare dental anomaly. It has been reported in holoprosencephaly (HPE) cases with severe facial anomalies or as a microform in autosomal dominant HPE (ADHPE). In our review of the literature, we note that SMMCI may also occur as an isolated finding or in association with other systemic abnormalities. These anomalies include short stature, pituitary insufficiency, microcephaly, choanal atresia, midnasal stenosis, and congenital nasal pyriform aperture stenosis. SMMCI can also be a feature of recognized syndromes or associations or a finding in patients with specific chromosomal abnormalities. We performed a molecular study on a cohort of 13 SMMCI patients who did not have HPE. We studied two genes, Sonic Hedgehog (SHH) and SIX3, in which mutations have been reported in patients showing SMMCI as part of the HPE spectrum. A new missense mutation in SHH (I111F), segregating in one SMMCI family, was identified. Our results suggest that this mutation may be specific for the SMMCI phenotype since it has not been found in the HPE population or in normal controls. Published 2001 Wiley-Liss, Inc.

Prenatal traces of aberrant neurofacial growth

The interrelation between the development of the brain/peripheral nerves and that of the surrounding bone tissue is termed neuro-osteology. In orthodontic and pediatric practice the development of the hard tissues is evaluated radiographically, but the development of the neural tissue within the bone tissue is not evaluated. In this review the emphasis is placed on two neuro-osteologic interrelations that can be observed on profile radiographs and orthopantomograms, respectively. One is the connection between the pituitary gland of the central nervous system and the sella turcica (profile radiograph), and the other is the association between the peripheral nerves and the development of the dentition (orthopantomogram). Pituitary gland/sella turcica: The correlation between prenatal malformation in the pituitary gland/sella turcica and the postnatal morphology of the sella turcica in holoprosencephaly, spina bifida/myelomeningocele, and cri-du-chat syndrome is demonstrated. Peripheral nerves/dentition: The prenatal innervation of the dentition is presented. Agenesis and tooth malformation occur in constant patterns within the dental arch fields that share the same innervation. The findings demonstrate that in postnatal diagnosis of the cranium and the teeth, traces of prenatal aberrations can be found that are important for neurofacial growth.