Retention of permanent incisors by mesiodens: a family affair

Comparative proteomic analysis of dental pulp from supernumerary and normal permanent teeth

OBJECTIVES

To obtain and compare the protein profiles of supernumerary and normal permanent dental pulp tissues.

MATERIALS AND METHODS

Dental pulp tissues were obtained from supernumerary and normal permanent teeth. Proteins were extracted and analyzed by liquid chromatography-tandem mass spectrometry (LC/MS-MS). Protein identification and quantification from MS data was performed with MaxQuant. Statistical analysis was conducted using Metaboanalyst to identify differentially expressed proteins (DEPs) (P-value < 0.05, fold-change > 2). Gene Ontology enrichment analyses were performed with gProfiler.

RESULTS

A total of 3,534 proteins were found in normal dental pulp tissue and 1,093 in supernumerary dental pulp tissue, with 174 DEPs between the two groups. This analysis revealed similar functional characteristics in terms of cellular component organization, cell differentiation, developmental process, and response to stimulus, alongside exclusive functions unique to normal permanent dental pulp tissues such as healing, vascular development and cell death. Upon examination of DEPs, these proteins were associated with the processes of wound healing and apoptosis.

CONCLUSIONS

This study provides a comprehensive understanding of the protein profile of dental pulp tissue, including the first such profiling of supernumerary permanent dental pulp. There are functional differences between the proteomic profiles of supernumerary and normal permanent dental pulp tissue, despite certain biological similarities between the two groups. Differences in protein expression were identified, and the identified DEPs were linked to the healing and apoptosis processes.

CLINICAL RELEVANCE

This discovery enhances our knowledge of supernumerary and normal permanent pulp tissue, and serves as a valuable reference for future studies on supernumerary teeth.

Non-syndromic supernumerary teeth and association with a self-reported family history of cancer

BACKGROUND

Supernumerary teeth are an alteration of dental developmental and result in the formation of teeth above the usual number. Epidemiologic studies suggested that patients with dentofacial anomalies and their family members may present an increased risk of developing cancer, including female breast cancer and gynecologic cancers. These observations indicate that genetic alterations that result in dental anomalies may be related to cancer development. Thus, the aim of the present study was to evaluate the association between supernumerary teeth and a family history of female breast cancer and gynecologic cancers.

METHODS

The diagnosis of supernumerary teeth was based on clinical and radiographic examinations. For data collection, a questionnaire asking for information regarding ethnicity, age, gender, and self-reported family history of cancer up to the second generation was used. Statistical analysis was performed using the Χ2 test and Fisher's exact test with an established α of 5%.

RESULTS

A total of 344 patients were included; 47 of them had one or more non-syndromic supernumerary teeth (not associated with any syndrome or cleft lip and palate) and 297 were control patients. Age, ethnicity, and gender distribution were not statistically different between the group with supernumerary teeth and the control group (p > 0.05). The supernumerary teeth were most commonly observed in the incisors area. Breast cancer (n = 17) was the most commonly self-reported type of cancer, followed by uterine cervical (n = 10), endometrial (n = 2), and ovarian (n = 1) cancers. Endometrial cancer was significantly associated with the diagnosis of supernumerary teeth (p = 0.017).

CONCLUSION

This study suggests that patients with supernumerary teeth possess a higher risk of having family members with endometrial cancer.

Genetic Variants in Protein Tyrosine Phosphatase Non-Receptor Type 23 Are Responsible for Mesiodens Formation

A mesiodens is a supernumerary tooth located in the midline of the premaxilla. In order to investigate the genetic etiology of mesiodens, clinical and radiographic examination and whole exome sequencing (WES) were performed in 24 family members of a two-generation Hmong family and additionally in two unrelated Thai patients with mesiodens. WES in the Hmong family revealed a missense mutation (c.1807G>A;p.Glu603Lys) in PTPN23 in seven affected members and six unaffected members. The mode of inheritance was autosomal dominance with incomplete penetrance (53.84%). Two additional mutations in PTPN23, c.2248C>G;p.Pro750Ala and c.3298C>T;p.Arg1100Cys were identified in two unrelated patients with mesiodens. PTPN23 is a regulator of endosomal trafficking functioning to move activated membrane receptors, such as EGFR, from the endosomal sorting complex towards the ESCRT-III complex for multivesicular body biogenesis, lysosomal degradation, and subsequent downregulation of receptor signaling. Immunohistochemical study and RNAscope on developing mouse embryos showed broad expression of PTPN23 in oral tissues, while immunofluorescence showed that EGFR was specifically concentrated in the midline epithelium. Importantly, PTPN23 mutant protein was shown to have reduced phosphatase activity. In conclusion, mesiodens were associated with genetic variants in PTPN23, suggesting that mesiodens may form due to defects in endosomal trafficking, leading to disrupted midline signaling.

Deep learning-based identification of mesiodens using automatic maxillary anterior region estimation in panoramic radiography of children

OBJECTIVES

The purpose of this study is to develop and evaluate the performance of a model that automatically sets a region of interest (ROI) and diagnoses mesiodens in panoramic radiographs of growing children using deep learning technology.

METHODS

Out of 988 panoramic radiographs, 489 patients with mesiodens were classified as an experimental group, and 499 patients without mesiodens were classified as a control group. This study consists of two networks. The first network (DeeplabV3plus) is a segmentation model that uses the posterior molar space to set the ROI in the maxillary anterior region with the mesiodens in the panoramic radiograph. The second network (Inception-resnet-v2) is a classification model that uses cropped maxillary anterior teeth to determine the presence of mesiodens. The data were divided into five groups and cross-validated. Deep learning model were created and trained using Inception-ResNet-v2. The performance of the segmentation network was evaluated using accuracy, Intersection over Union (IoU), and MeanBFscore. The overall network performance was evaluated using accuracy, precision, recall, and F1-score.

RESULTS

Segmentation performance using posterior molar space in panoramic radiographs was 0.839, IoU 0.762, and MeanBFscore 0.907. The mean values of accuracy, precision, recall, F1-score, and area under the curve for the diagnosis of mesiodens using automatic segmentation were 0.971, 0.971, 0.971, 0.971, and 0.971, respectively.

CONCLUSIONS

The diagnostic performance of the deep learning system using posterior molar space on the panoramic radiograph was sufficiently useful. The results of the deep learning system confirmed the possibility of complete automation of the classification of mesiodens.

Non-Syndromic Familial Mesiodens: Presentation of Three Cases

Mesiodens are the most common supernumerary teeth and are detected incidentally during routine radiographic examination, so late diagnosis complications are very common. The dentist must make a timely diagnosis and thus avoid clinical complications. Despite advances in knowledge of dental morphogenesis and differentiation, the etiology of mesiodens remains unclear. Therefore, several theories have been postulated to explain how and why they develop. It was described in the literature that heredity could play an important role in the appearance of supernumerary teeth, with a higher rate of appearance in relatives of those affected. This article reports three cases, a mother and two children, who present mesiodens, which shows that supernumerary teeth may involve a genetic factor. In addition, a literature review was carried out to assess the importance of the genetic factor as a possible cause of mesiodens. The relevance and implications of timely diagnosis in clinical practice to avoid manifestations of clinical complications are discussed. Therefore, the identification of the genetic risk factors responsible for the formation of supernumerary teeth is essential for developing a screening tool to determine an individual’s genetic risk.

Clinical Analysis of Approach Selection of Extraction of Maxillary Embedded Mesiodens in Children

Objective

To analyze the relationship between the position of embedded mesiodens in maxilla and surgical approach in children and thus provide reference materials for surgical design.

Methods

According to the preoperative cone-beam computed tomography (CBCT) examination, the location and surgical approach characteristics of 625 children aged 4-16 years old who presented with embedded mesiodens in maxilla and were diagnosed in our department from January 2016 to December 2021 were statistically analyzed.

Results

There were 877 embedded mesiodens in 625 children. The selected cases were classified according to the axial angle relationship between mesiodens and adjacent normal teeth or tooth germs, including 84 cases of acute angle type (including the same direction) (13.4%), 66 cases of vertical type (10.6%), 114 cases of obtuse angle type (18.2%), 271 cases of inverted type (43.4%), and 90 cases of mixed type (14.4%). The palatal gingival margin approach was the most selected surgical approach for the cases of acute angle (including synclastic), obtuse angle, and inverted type, and the palatal gingival margin approach and the combined labial-palatal approach were the most selected surgical approach for the cases of vertical and mixed type.

Conclusion

Palatal gingival margin approach was the most common surgical approach for various types of embedded mesiodens in maxilla in children. Surgeons should classify the case of mesiodens according to the preoperative imaging examination and design the surgical approach reasonably.

Biological characteristics of dental pulp stem cells and their potential use in regenerative medicine

BACKGROUND

Regenerative medicine has emerged as a multidisciplinary field with the promising potential of renewing tissues and organs. The main types of adult stem cells used in clinical trials are hematopoietic and mesenchymal stem cells (MSCs). Stem cells are defined as self-renewing clonogenic progenitor cells that can generate one or more types of specialized cells.

HIGHLIGHT

MSCs form adipose, cartilage, and bone tissue. Their protective and regenerative effects, such as mitogenic, anti-apoptotic, anti-inflammatory, and angiogenic effects, are mediated through paracrine and endocrine mechanisms. Dental pulp is a valuable source of stem cells because the collection of dental pulp for stem cell isolation is non-invasive, in contrast to conventional sources, such as bone marrow and adipose tissue. Teeth are an excellent source of dental pulp stem cells (DPSCs) for therapeutic procedures and they can be easily obtained after tooth extraction or the shedding of deciduous teeth. Thus, there is increased interest in optimizing and establishing standard procedures for obtaining DPSCs; preserving well-defined DPSC cultures for specific applications; and increasing the efficiency, reproducibility, and safety of the clinical use of DPSCs.

CONCLUSION

This review comprehensively describes the biological characteristics and origins of DPSCs, their identification and harvesting, key aspects related to their characterization, their multilineage differentiation potential, current clinical applications, and their potential use in regenerative medicine for future dental and medical applications.

Sequencing analysis of exons 5 and 6 in RUNX2 in non-syndromic patients with supernumerary tooth in Kelantan, Malaysia

OBJECTIVE

The aim of this study is to do a sequencing analysis of RUNX2 in non-syndromic patients with supernumerary tooth.

MATERIALS AND METHODS

Fifty-three patients with supernumerary tooth were identified retrospectively from 1,275 radiographic reviews who attended the Hospital Universiti Sains Malaysia (USM) Dental Clinic. Informed consent was obtained from the patients prior to the study. Blood samples were collected from 41 patients and DNA extractions were performed out of which 10 samples were chosen randomly for PCR amplification using designated primers for RUNX2 followed by DNA sequencing analysis.

RESULTS

This study involved 28 male patients (68.3%) and 13 female patients (31.7%) with a gender ratio of 2.2:1 and mean age of 15.9 ± 6.2 years. DNA extraction yielded ~ 40 ng/μl of concentrated DNA, and each DNA sample had more than 1500 bp of DNA length. The purity ranged between 1.8 and 2.0. DNA sequencing analysis did not reveal any mutations in exons 5 and 6 of RUNX2.

CONCLUSION

This study did not reveal any mutations in exons 5 and 6 of RUNX2 in non-syndromic patients with supernumerary tooth.

CLINICAL RELEVANCE

Analysis of mutations in RUNX2 is important to enhance the understanding of tooth development in humans.

Genetics of Dentofacial and Orthodontic Abnormalities

The development of craniofacial complex and dental structures is a complex and delicate process guided by specific genetic mechanisms. Genetic and environmental factors can influence the execution of these mechanisms and result in abnormalities. An insight into the mechanisms and genes involved in the development of orofacial and dental structures has gradually gained by pedigree analysis of families and twin studies as well as experimental studies on vertebrate models. The development of novel treatment techniques depends on in-depth knowledge of the various molecular or cellular processes and genes involved in the development of the orofacial complex. This review article focuses on the role of genes in the development of nonsyndromic orofacial, dentofacial variations, malocclusions, excluding cleft lip palate, and the advancements in the field of molecular genetics and its application to obtain better treatment outcomes.

Epidemiological Features and Clinical Repercussions of Supernumerary Teeth in a Multicenter Study: A Review of 518 Patients with Hyperdontia in Spanish Population

OBJECTIVES

 The aim of this study was to establish the prevalence of supernumerary teeth (ST) in a sector of the population of Madrid, as well as possible complications associated with the presence of these teeth.

MATERIALS AND METHODS

 The study investigated patients (n = 28,114) who sought dental care at the Oral Surgery Service of three different centers between May 2005 and April 2018. Cases that did not present this numeric dental developmental variation were discarded, registering only those presenting ST.

STATISTICAL ANALYSIS

 Statistical analysis consisted of univariate analysis (mean, standard deviation, median, etc.), bivariate analysis applying the chi-squared test, whereby statistical significance was established with a confidence interval (CI) of 95% (p < 0.05), and multivariate analysis by means of classification and decision trees.

RESULTS

 The study found ST in 518 patients, representing a prevalence of 1.84%. The 518 patients presented a total of 726 ST. Distomolars were the most common, representing 37.7% of the sample, followed by premolars (20.1%). About 70.5% of the sample were located in the maxilla and 78% of ST were impacted. Radiographs revealed that 39.7% of STs were associated with disorders. Supplementary morphology appeared in 52.1% of the sample.

CONCLUSIONS

 Although mesiodens is considered the most common ST, the present study found distomolars and supernumerary premolars to be the most frequently occurring. Pathology was associated with 39.7% of the ST sample. Early diagnosis allows optimal patient management and treatment planning, with intervention at an appropriate time to prevent complications in development and so reduce later treatment need.

Analysis of the distribution of supernumerary teeth and the characteristics of mesiodens in Bengbu, China: a retrospective study

OBJECTIVES

To evaluate the distribution of supernumerary teeth (ST) and the characteristics of mesiodens.

METHODS

Panoramic radiographs of 48,700 outpatients were used to assess the distribution of ST. A total of 142 cone beam computed tomography (CBCT) images were used to evaluate the characteristics of mesiodens.

RESULTS

A total of 1.24% of individuals aged from 1 to 98 years were diagnosed with ST among 48,700 outpatients, and males had a higher percentage of ST than females (2.94:1); patients aged 6-12 years were the most frequently diagnosed. More females had ST impacted in bone than males. The percentages of patients with 1 and 2 ST were 0.949 and 0.290%, respectively. The most frequent location, crown direction, and morphology of mesiodens were palatal, inverted, and conical, respectively. The tooth lengths of mesiodens in males and of erupted mesiodens were longer than that those in females and of unerupted mesiodens, respectively. Inverted mesiodens had the shortest tooth length compared with vertical and horizontal mesiodens. These results were statistically significant.

CONCLUSIONS

The distribution of ST and mesiodens were both related to gender, and patients aged 6-12 years were the most frequently detected. The length of the mesiodens was associated with the growth direction and mesiodens eruption.

Two Rare Cases of Non-Syndromic Paramolars with Family Occurrence and a Review of Literature

Supernumerary teeth (or hyperdontia) are teeth that exceed the normal number of deciduous or permanent teeth in the oral cavity. The occurrence of supernumerary teeth without any associated syndrome has been frequently reported and many case reports have been published. This article reports two rare cases of familial occurrence of multiple paramolars without the presence of any other syndrome for two consecutive generations. Limited cases of bilateral maxillary or mandibular paramolars have been reported. In addition, prevalence, classification, etiology, complications, diagnosis and therapeutic strategies that may be adopted when supernumeraries occur are discussed. A review of similar cases published in the literature is included as well.

The prevelance of mesiodens in a group of non-syndromic Turkish children: a radiographic study

Purpose

The aim of the present study is to determine the prevelance and clinical status of mesiodens in a group of non-syndromic Turkish children, with an analysis of the associated clinical-eruptive complications.

Materials and Methods

This study sample consists of 58142 pediatric patients'. Standard equipment and films were used in the suspected patients. The examination of all radiographs was performed under standard conditions by two pediatric dentists with over 10 years experience. Age, gender, number of mesiodens, morphology and clinical status were recorded in forms.

Results

A total of 83 mesiodentes were diagnosed in 59 children with ages ranging from 6-14 years. The prevelance of mesiodens was estimated as 0.1%. Males were more frequently affected than females in the ratio of 2.3:1. Of the 83 mesiodentes, 48.2% were conical, 31.3% were tuberculate and 20.5% were incisor like, 22.9% were inverted, and 68.7% were fully impacted. The number of mesiodens was one in 36 cases (61.0%), two in 22 cases (37.3%) and three in one case (1.7%). The mean age at the time of diagnosis of the mesiodens was 9.5 years. The main complication associated with the mesiodens was displacement or rotation of the permanent teeth (73.3%).

Conclusion

This study presents 0.1% prevelance of mesiodens in a group of Turkish children sample. The majority of the mesiodentes were unilateral located in the premaxillary region, were conical shaped, and remained unerupted. The mean age at the time of diagnosis of the mesiodens in this study was 9.5 years, with this period being later than the eruption time of the maxillary central incisor.

Histological and chemical analyses of mesiodens development and mineralization

OBJECTIVE

This study aimed to compare the developmental timing and mineralization quality of mesiodentes, i.e., supernumerary teeth located mainly in the midline of the maxilla between the central incisors, with the developmental timing and mineralization quality of permanent and primary central incisors.

DESIGN

Sixteen mesiodentes, nine permanent and seven primary central incisors were collected. The location of the neonatal line was determined using a light microscope at 10× or 20× enlargements. Chemical composition of the enamel at two locations was analyzed using energy dispersive X-ray spectrometer.

RESULTS

Neonatal lines were observed in eight out of 16 mesiodentes, in all primary central incisors and in none of the permanent central incisors. Chemical analyses showed that mesiodentes mineralization was impaired, resulting in higher amount of organic ions and reduced inorganic ions. Discriminant analysis showed minimal overlap of mesiodentes with either primary or permanent centrals.

CONCLUSIONS

Mesiodentes development begins before birth in 50% of the cases but later than the primary centrals. Mineralization of mesiodens is impaired with less mineral content and higher organic content. The results showed that mesiodentes are a special group of teeth with defective morpho-differentiation and mineralization, with little similarity to primary or permanent central incisors.

Genetic alterations in mesiodens as revealed by targeted next-generation sequencing and gene co-occurrence network analysis

OBJECTIVE

Mesiodens is the most common type of supernumerary tooth which includes a population prevalence of 0.15%-1.9%. Alongside evidence that the condition is heritable, mutations in single genes have been reported in few human supernumerary tooth cases. Gene sequencing methods in tradition way are time-consuming and labor-intensive, whereas next-generation sequencing and bioinformatics are cost-effective for large samples and target sizes.

MATERIALS AND METHODS

We describe the application of a targeted next-generation sequencing (NGS) and bioinformatics approach to samples from 17 mesiodens patients. Subjects were diagnosed on the basis of panoramic radiograph. A total of 101 candidate genes which were captured custom genes were sequenced on the Illumina HiSeq 2500. Multistep bioinformatics processing was performed including variant identification, base calling, and in silico analysis of putative disease-causing variants.

RESULTS

Targeted capture identified 88 non-synonymous, rare, exonic variants involving 42 of the 101 candidate genes. Moreover, we investigated gene co-occurrence relationships between the genomic alterations and identified 88 significant relationships among 18 most recurrent driver alterations.

CONCLUSION

Our search for co-occurring genetic alterations revealed that such alterations interact cooperatively to drive mesiodens. We discovered a gene co-occurrence network in mesiodens patients with functionally enriched gene groups in the sonic hedgehog (SHH), bone morphogenetic proteins (BMP), and wingless integrated (WNT) signaling pathways.

Diagnosis and Surgical Management of Nonsyndromic Nine Supernumerary Teeth and Leong's Tubercle

Nonsyndromic multiple supernumerary teeth (ST) and Leong's tubercle are a condition with a very low prevalence and a multidisciplinary approach is required to restore function and aesthetics. So, this case report aimed at presenting a rare case of nonsyndromic nine supernumerary teeth and Leong's tubercle in a pediatric patient, without any evident familial history, showing its diagnosis and surgical management.

A retrospective study of deep sedation with concomitant administration of sedative agents in children undergoing surgical removal of a mesiodens

BACKGROUND

Pediatric dentists face challenges when young patients require a mesiodens extraction. General anesthesia may be a burden to the child as well as the parent due to dental fears and costs. The aim of this study was to evaluate oral and intravenous sedation in the outpatient setting as a safe and effective means of managing patients who require a mesiodens extraction.

METHODS

Records were reviewed retrospectively to find patients who underwent a mesiodens removal procedure from January 2013 to September 2014 in the Department of Pediatric Dentistry at Ajou University Hospital (Suwon, Gyeonggi-do, Republic of Korea). A total of 81 patients (62 male and 19 female) between 4 and 11 years of age (mean [± SD] 81.6 ± 14.1 months) were studied, with a mean weight of 22.9 ± 3.3 kg (16 kg to 30 kg). Vital signs, sedation drug dosage, and sedation time were studied.

RESULTS

Mean doses of 63.7 ± 2.5 mg/kg chloral hydrate and 1.36 ± 0.22 mg/kg hydroxyzine were used for oral sedation. Nitrous oxide/oxygen was administrated for 40.0 ± 2.1 min. The mean dose of midazolam administered intravenously was 0.14 ± 0.06 mg/kg (2.38 ± 0.97 times). In all cases, the mesiodens was removed successfully.

CONCLUSIONS

Intravenous sedation combined with oral sedation and nitrous oxide/oxygen inhalation can be an alternative to general anesthesia when administrated and monitored properly.

A comparative analysis of patients with mesiodenses: a clinical and radiological study

Objectives

A mesiodens appears most commonly as a supernumerary tooth impacted in the anterior maxilla. The purpose of this study is analyze mesiodens clinically.

Materials and Methods

Gender, crown form, direction of impaction, relation to permanent incisors, and chief complaints of patients with extracted mesiodens were analyzed.

Results

Patients were analyzed for motivation to visit the hospital; 85.4% of the patients were referred from other hospitals. Mesiodens was more common in males than in females (3.7:1), and 70.1% of patients had only one mesiodens, while 29.6% had two mesiodenses. Of the mesiodenses, 61.4% were of the aconical form, and the most common direction was upward (62.4%), followed by the normal position (26.0%) and the horizontal position (11.6%). The mesiodenses caused orthodontic problems with the permanent incisors in 46.3% of cases. Mesiodens associated with dentigerous cyst was rarely observed in our patient group.

Conclusion

Mesiodens is more common in males than in females and often affects the permanent incisors. Thus, careful clinical and radiological evaluations of mesiodenses are important.

Prevalence of mesiodens in orthodontic patients with deciduous and mixed dentition and its association with other dental anomalies

OBJECTIVE

To determine the prevalence of mesiodens in deciduous and mixed dentitions and its association with other dental anomalies.

MATERIAL AND METHODS

Panoramic radiographs of 1,995 orthodontic patients were analyzed retrospectively, obtaining a final sample of 30 patients with mesiodens. The following aspects were analyzed: gender; number of mesiodens; proportion between erupted and non-erupted mesiodens; initial position of the supernumerary tooth; related complications; treatment plan accomplished; and associated dental anomalies. The frequency of dental anomalies in the sample was compared to reference values for the general population using the chi-square test, with a significance level set at 5%.

RESULTS

The prevalence of mesiodens was 1.5% more common among males (1.5:1). Most of the mesiodens were non-erupted (75%) and in a vertical position, facing the oral cavity. Extraction of the mesiodens was the most common treatment. The main complications associated with mesiodens were: delayed eruption of permanent incisors (34.28%) and midline diastema (28.57%). From all the dental anomalies analyzed, only the prevalence of maxillary lateral incisor agenesis was higher in comparison to the general population.

CONCLUSIONS

There was a low prevalence of mesiodens (1.5%) in deciduous and mixed dentition and the condition was not associated with other dental anomalies, except for the maxillary lateral incisor agenesis.

Mirror imaging of impacted and supernumerary teeth in dizygotic twins: A case report

Background: Mesiodens is the most common type of supernumerary tooth found in the premaxilla. It might be discovered by the clinical examination by chance on a radiograph or as the cause of an unerupted maxillary central incisor. The genetic transmission of supernumerary and impacted teeth is poorly understood. Mirror imaging in twins has been reported frequently in relation to several unilateral dental anomalies including mesiodens. This phenomenon is the appearance of an asymmetrical feature or anomaly occurring on the right side of one twin but on the left side of the other twin. The event of mesiodens mirror imaging in monozygotic twins has been described in literature. Results: This is the first reported case of mesiodens mirror images in dizygotic twins. The de-scribed mesiodens caused the eruption failure of maxillary permanent incisors. The super-numerary teeth were removed to facilitate the spontaneous eruption of the impacted perma-nent maxillary incisors. Clinical Implications: Studies related to supernumerary teeth can be useful to clinicians in the early diagnosis of this anomaly. Clinical and radiographic examinations provide a correct therapeutic approach.

Key words:Supernumerary teeth, twins, dental development.

Under your nose: a rare finding during dissection provides insights into maxillary supernumerary teeth

BACKGROUND

A supernumerary tooth was found during anatomical dissection. The position of this tooth, still impacted in the maxilla, and the associated pathology make this a rare case.

METHODS

During dissection by dental students of the sagittally-sectioned head of a cadaver, a supernumerary tooth was identified in the mid-palatal area. Further dissection revealed a swelling with a thin bony covering related to the crown of the tooth. The maxilla was removed en bloc and radiographic examination, CT scanning, electron microscopy and histology were undertaken.

RESULTS

The tooth had a crenulated occlusal surface and a single root. It was 25 mm posterior to the root apex of the permanent upper central incisor. The swelling, confirmed by radiographs and CT imaging to be associated with the crown, occupied approximately one-third of the maxillary sinus. The 3D shape of the cystic lesion was visualized by a composite digital movie.

CONCLUSIONS

The crown form, position of the tooth and the associated dentigerous cyst suggested it was a palatally developing supernumerary premolar which had been displaced to the palatal midline by the expanding cyst. This rare case highlights the learning and teaching opportunities available during dissection, showing important variations in both development and clinical anatomy.

An unusual double supernumerary maxillary mesiodens in a Middle Iron Age skeleton from South Uist, Western Isles, Scotland

OBJECTIVE

Bilaterally occurring and fully erupted mesiodens occur infrequently in the modern population and have been little documented from past populations. This research presents an unusual case of a double maxillary mesiodens in the permanent dentition occurring in skeletal remains dating to the Middle Iron Age (250-410 AD) from South Uist, Western Isles of Scotland.

METHODS

Osteological analysis of an adult male included the inventory of teeth present/absent and analysis of dental pathologies (caries, calculus, periodontal disease, ante-mortem tooth loss, periapical abscesses), developmental defects and orthodontic anomalies (enamel hypoplastic defects, malposition, rotation, crowding, agenesis and supernumerary teeth).

RESULTS

An unusual expression of double, fully erupted, mesiodens in the anterior permanent maxillary dentition representing supernumerary central incisors exists. The complete eruption had contributed to anterior displacement of one central incisor alveolar socket similar to documented modern clinical cases. Shallow sockets also implied an associated stunted development of the original central maxillary incisor roots. Occlusal enamel wear indicated the mesiodens had been abraded during mastication.

CONCLUSION

Current clinical data suggest there is a much higher tendency for single mesiodens to exist rather than double and examples often fail to fully erupt into the dentition. This relative rarity may account for the few previous reports of this dental anomaly from past human remains and especially of this date. The fully erupted double example from South Uist contributes to the known evidence for orthodontic anomalies in the past.

Aetiology of supernumerary teeth: a literature review

BACKGROUND

Supernumerary teeth are teeth, or tooth-like structures that have either erupted or remain unerupted in addition to the 20 primary and 32 permanent teeth.

AIMS

This paper attempts to (a) provide an overview of the proposed hypotheses and the current understanding of the aetiology of supernumerary teeth, and (b) review the published cases of supernumerary teeth occurring in families.

REVIEW

No studies have been able to distinguish between different aetiologies for the different locations of supernumerary teeth, while, from a developmental or molecular perspective, the proposed hypotheses may be plausible and explains the origin of different types of supernumerary teeth.

CONCLUSION

The only clearly evident feature, based on the existing published reports, is that it is logical to state that supernumerary teeth have a genetic component in their aetiology.

Genetics and presence of non-syndromic supernumerary teeth: A mystery case report and review of literature

Presence of supernumerary teeth is well-recognized clinical phenomenon. However, it is uncommon to find multiple supernumeraries in individuals with no other associated disease or syndrome. Presence of multiple supernumerary teeth is thought to have genetic component. We report a rare case where multiple supernumerary teeth were seen without presence of any other syndrome in 3 generations; father, son, and two grandsons. We also present a review of similar cases published in literature till date. The role of genetics in development of supernumerary teeth is highlighted.

Bilateral Mesiodens in Monozygotic Twins: 3D Diagnostic and Management

Mesiodens is the most frequent type of supernumerary tooth and may occur in several forms, causing different local disorders, such as impaction of the anterior permanent teeth. High-resolution three-dimensional (3D) images have improved the diagnosis and treatment plan of patients with impacted and supernumerary teeth. The purpose of this paper was to report a case of two mesiodens in monozygotic twin boys with appropriate 3D diagnostic and treatment plan.

Nonsyndromic multiple hyperdontia in a series of 13 patients: epidemiologic and clinical considerations

BACKGROUND

The authors conducted a retrospective-casuistic study to determine the prevalence of nonsyndromic multiple hyperdontia in a sample of the population of Madrid, as well as possible complications associated with the presence of such supernumerary teeth.

METHODS

The study included a data assessment of all patients seeking dental care at a hospital's department of oral surgery across four years. The authors studied data from patients who had nonsyndromic multiple hyperdontia. We used univariate and bivariate analysis to make comparisions between variables.

RESULTS

The authors identified nonsyndromic multiple hyperdontia in the records of 13 patients (0.1 percent) of the total population studied. These patients had 55 supernumerary teeth. Premolars were the most frequently seen type of supernumerary tooth and constituted 45.5 percent of the sample.

CONCLUSIONS

Nonsyndromic multiple hyperdontia usually is diagnosed as a coincidental radiographic finding in the course of routine examination rather than as the result of an associated disease. However, the authors found a higher percentage of comorbidity than they initially expected; mechanical or obstructive pathology was associated with 20.0 percent of the supernumerary teeth and enlargement of the follicular sac of more than 3 millimeters was present in 23.6 percent of the sample.

CLINICAL IMPLICATIONS

The early diagnosis and follow-up of patients with multiple supernumerary teeth should help clinicians prevent the diseases associated with this kind of hyperodontia.

Supernumerary teeth: Report of four unusual cases

Supernumerary tooth denotes duplication of tooth in the normal series. It is a developmental anomaly and has been argued to arise from multiple etiologies. These teeth may remain embedded in the alveolar bone or can erupt into the oral cavity. The supernumerary tooth might cause esthetic and/or functional problems, especially if it is situated in the maxillary anterior region. Complications reported were delayed or prevented eruption of succedaneous teeth, displacement or rotation, crowding of the affected region, abnormal diastema, dilacerations, cystic formation, and sometime eruption into the nasal cavity. In this case report, four unusual cases of supernumerary teeth that resulted in varying degrees of disturbances in permanent dentition are presented. Conservative surgical intervention and light orthodontic forces were used to bring the teeth into normal position with minimal disturbance to the surrounding oral structures.

Clinical epidemiological analysis of 173 supernumerary molars

OBJECTIVES

To determine the prevalence of supernumerary molars in a sector of the population of Madrid, as well as the possible complications associated with the presence of hypergenetic molars.

MATERIALS AND METHODS

A retrospective, descriptive study was carried out, which included a data assessment of all patients (13557) seeking dental care at a hospital's department of oral surgery across 4 years. The proposed methodology consisted of preparing a medical record in order to obtain data on the medical record number, age and sex of the patient, radiological findings such as location and type of supernumerary molar, retained/erupted molar, related accidents and tooth morphology.

RESULTS

Supernumerary molars were found to be present in 130 patients, representing a prevalence of 0.96% of the total population studied. These patients had a total of 173 hypergenetic molars, consisting of 137 distomolars and 36 paramolars Mechanical-obstructive pathology was associated with 28.9%, whereas enlargement of the follicular sack bigger than 3 mm was present in 16.2% of the sample.

CONCLUSION

Supernumerary molars are usually diagnosed as a coincidental radiological finding without any associated pathology. However a higher percentage of comorbidity was found than initially expected.

Multiple supernumerary teeth associated with an impacted maxillary central incisor: Surgical and orthodontic management

Various anomalies in the size, shape, number, structure and eruption of the teeth are often observed clinical conditions. Supernumerary teeth can be found in almost any region of the dental arch, and most of the times they are asymptomatic, and are routinely found during radiographic evaluation. The most common cause of impacted maxillary incisors is the presence of the supernumerary teeth. This paper describes a case of multiple supernumerary teeth associated with an impacted permanent maxillary central incisor in an 11-year old child along with its surgical and orthodontic management.

Management of Delayed Eruption of Permanent Maxillary Incisor associated with the Presence of Supernumerary Teeth: A Case Report

A supernumerary tooth is one that is additional to the normal series and can be found in almost any region of the dental arch. Clinically, supernumerary teeth are able to cause different local disorders. It is important for the dentist to be aware of the clinical complications of supernumerary teeth, the most common being the delayed eruption of permanent teeth. Early diagnosis and management of supernumerary teeth is important to prevent the need for more complex surgical and orthodontic treatment. This case report highlights the problem of delayed eruption of permanent maxillary left central incisor in a 9-year-old boy due to two supernumerary teeth, one tuberculate type and other impacted inverted mesiodens.

Molecular genetics of supernumerary tooth formation

Despite advances in the knowledge of tooth morphogenesis and differentiation, relatively little is known about the aetiology and molecular mechanisms underlying supernumerary tooth formation. A small number of supernumerary teeth may be a common developmental dental anomaly, while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans. Mice, which are commonly used for studying tooth development, only exhibit one dentition, with very few mouse models exhibiting supernumerary teeth similar to those in humans. Inactivation of Apc or forced activation of Wnt/β(catenin signalling results in multiple supernumerary tooth formation in both humans and in mice, but the key genes in these pathways are not very clear. Analysis of other model systems with continuous tooth replacement or secondary tooth formation, such as fish, snake, lizard, and ferret, is providing insights into the molecular and cellular mechanisms underlying succesional tooth development, and will assist in the studies on supernumerary tooth formation in humans. This information, together with the advances in stem cell biology and tissue engineering, will pave ways for the tooth regeneration and tooth bioengineering.

A clinical epidemiologic analysis of a sample of 73 supernumerary premolars

BACKGROUND

The authors conducted a retrospective study to determine the prevalence of supernumerary premolars in sample of patients from Madrid, as well as the possible complications associated with the presence of such supernumerary premolars.

METHODS

The study included a data assessment of all patients seeking dental care at a hospital's department of oral surgery across four years. The authors studied data from patients who had supernumerary premolars.

RESULTS

The authors identified supernumerary premolars in the records of 43 patients (0.32 percent) of the total population studied. These patients had 73 hyperdontic premolars (65 mandibular premolars [89 percent] and eight maxillary premolars [11 percent]).

CONCLUSIONS

Supernumerary premolars usually are diagnosed as a coincidental radiographic finding without an associated pathology. However, the authors found a higher percentage of comorbidity than they initially expected.

CLINICAL IMPLICATIONS

Mechanical or obstructive pathology was associated with 2.7 percent of the premolars, and enlargement of the follicular sac of more than 3 millimeters was present in 26.0 percent of the sample.

Prevalence of dental anomalies in various malocclusions

INTRODUCTION

The purpose of this study was to evaluate the prevalence of dental anomalies in different orthodontic malocclusions.

METHODS

Based on pretreatment diagnostic records, 900 orthodontic patients were classified as Class I (n = 358), Class II (n = 325), Class II Division 2 (n = 51), or Class III (n = 166). The occurrence rates of each dental anomaly were calculated as percentages of the total sample. Differences in incidence rates of each dental anomaly by sex and malocclusion were analyzed by using chi-square, Fisher exact, and z tests. The Mann-Whitney U test was used to determine whether there were significant differences in the occurrence of dental anomalies by age.

RESULTS

It was found that 40.3% of patients (n = 363) had at least 1 dental anomaly. Agenesis was the most common (21.6%), followed by dens evaginatus (6.2%), invaginatus (5.0%), pulp stones (4.2%), and impaction (2.9%). No statistically significant correlations were found between dental anomaly and type of malocclusion, with the exception of impaction and short or blunt roots (P <0.01 and P <0.05, respectively). The Mann-Whitney U test indicated no significant difference in dental anomalies by age.

CONCLUSIONS

A remarkably high rate of dental anomalies was recorded in orthodontic patients; therefore, orthodontists should carefully examine pretreatment records for dental anomalies to include their management in the treatment planning.

Surgical management of palatal placed, inverted, dilacerated and impacted mesiodens

Teeth may vary in size, shape and number. Mesiodens is the most commonly occurring supernumerary tooth, usually seen between upper two central incisors which may be impacted or erupted. The present paper describes a rare case of palatal placed, inverted, severely dilacerated and impacted mesiodens which was detected on radiographic examination for some other problem.

Problems of supernumerary teeth, hyperdontia or dentes supernumerarii

Supernumerary teeth are extra teeth or toothlike structures which may have either erupted or unerupted in addition to the 20 deciduous teeth and the 32 permanent teeth. This article provides an overview of frequency, distribution and classification of supernumerary teeth. The etiology of supernumerary teeth is still unknown, yet various theories have been presented based on epidemiological studies. Four clinical cases representing the possible manifestations of supernumerary teeth are discussed.

A non-syndrome case with bilateral supernumerary canines: report of a rare case

Supernumerary teeth are described as the teeth formed in excess of the normal dental formula. Prevalence of supernumerary teeth varies between 0.1% and 3.8% in general Caucasian population. They have been reported in both the primary and the permanent dentition. Supernumerary teeth may occur in any region of the dental arch. However, a supernumerary tooth in the canine region is a rare condition and to our knowledge, a non-syndrome case with bilateral supplemental maxillary canines did not exist in the literature. It was the aim of this report to evaluate this rare case in view of both oral radiology and orthodontics.

Delayed tooth eruption: pathogenesis, diagnosis, and treatment. A literature review

Delayed tooth eruption (DTE) is the emergence of a tooth into the oral cavity at a time that deviates significantly from norms established for different races, ethnicities, and sexes. This article reviews the local and systemic conditions under which DTE has been reported to occur. The terminology related to disturbances in tooth eruption is also reviewed and clarified. A diagnostic algorithm is proposed to aid the clinician in the diagnosis and treatment planning of DTE. The sequential and timely eruption of teeth is critical to the timing of treatment and the selection of an orthodontic treatment modality. This review addresses the need for a more in-depth understanding of the underlying pathophysiology of DTE and gives the clinician a methodology to approach its diagnosis and treatment.

Supernumerary teeth: review of the literature and a survey of 152 cases

INTRODUCTION

A review of the literature relating to supernumerary teeth is presented along with a survey of 152 cases.

METHODS

The study population consisted of 152 children who visited the department of Paediatric Dentistry at the Jordan University Hospital. Patients ranged in age from 5 to 15 years. Supernumeraries were detected by clinical examination and radiographs.

RESULTS

Males were affected more than females with a sex ratio of 2.2 : 1. Seventy-seven percent of the patients had one supernumerary tooth, 18.4% had double teeth, and 4.6% had three or more supernumeraries. Ninety percent of the supernumerary teeth occurred in the premaxilla, of which 92.8% were in the central incisor region and of these latter 25% were located in the midline. The other 10.4% of the supernumeraries were located in the premolar, canine, molar, and lower central incisor regions. Two cases were of non-syndrome supernumerary teeth. Seventy-five percent of the supernumeraries were conical, 83.1% were in the normal vertical position and 26.5% were erupted. Conical-shaped supernumerary teeth had a significantly higher rate of eruption compared to the tuberculate type.