Aetiology of supernumerary teeth: a literature review

Minimally invasive intraoral removal of mesiodens via a transnasal, non-endoscopic approach: a systematic review on the purpose of 10 cases

Mesiodens, which emerge towards the nasal cavity, often require consultation in maxillofacial practice. Typically accessed through wide palatal flaps with ostectomy, this method involves limited visibility and poses the risk of damaging the roots and apex of adjacent dental structures. This study advocates a minimally invasive technique that involves vestibulotomy between the central incisors, facilitating direct and rapid access through nasal floor dissection, minimizing comorbidities. A systematic review was performed, following the PRISMA guidelines, apropos on ten clinical cases reported in this study. The MEDLINE/Pubmed and Web of Science databases were searched. Several variables were considered and are presented comprehensively in tables and figures. Additionally, 10 case reports with mesiodens in the maxilla were submitted to surgical treatment using a minimally invasive intraoral transnasal disinclusion. The initial literature search resulted in 37 articles, of which 9 met the inclusion criteria for the analysis. Regarding postoperative complications, no bone exposure, incisor root damage, extensive surgical approach, palatal or vestibular hematoma, or palatal necrosis was observed. However, 10% experienced superficial damage to the nasopalatine neurovascular, while 80% and 20% presented mild and moderate postoperative facial edema, respectively. Hypoesthesia in 20% of patients recovered in the first week, 40% in the first month and 40% at 3 months. The minimally invasive intraoral, transnasal, non-endoscopic approach emerges as a safe and predictable alternative to conventional surgical techniques. Presumes minimal postoperative complications, mitigating the risk of excessive bone removal and damage to adjacent structures.

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

BACKGROUND

Pattern of dental anomalies encountered in cleft patients shows subtle signs of genetic involvement. This study aimed to evaluate the prevalence and pattern of tooth agenesis and supernumerary teeth in Thai cleft population according to the cleft type.

METHODS

Data collected from patients with cleft lip and palate, who had been treated at Tawanchai Cleft Center, Khon Kaen University, Thailand, available during year 2012-2022, were investigated. Records from 194 patients with non-syndromic clefts met the inclusion criteria. Standard dental records, and at least either orthopantomogram (OPG) or cone beam computed tomography (CBCT), were examined. Statistical analysis was performed using chi-square and binominal test (p ≤ 0.05).

RESULTS

Prevalence of tooth agenesis was higher (77.3%) than that of supernumerary teeth (5.7%) and was more common in bilateral cleft lip and palate (BCLP) (88.1%) than in unilateral cleft lip and palate (UCLP) (72.6%) (p = 0.017). The upper lateral incisor was more frequently affected (46.4%), followed by the upper second premolar. The number of missing teeth observed on the left side was significantly higher. Patients with left UCLP (ULCLP) had the highest prevalence of tooth agenesis. A total of 41 tooth agenesis code (TAC) patterns was found. The prevalence of supernumerary teeth was comparable with 6.6% of ULCLP, 5.1% of BCLP, and 4.5% of URCLP. Tooth-number anomalies were observed more often in the BCLP and were most likely to occur on the left side of the maxilla. Both types of anomalies could be featured in a small proportion of cleft patients.

CONCLUSIONS

More than half of the patients with non-syndromic cleft lip and palate in this study, presented with tooth-number anomalies. Tooth agenesis was approximately 10-time more prevalent than supernumerary teeth. Tooth agenesis was likely to appear on the left-side of the maxilla regardless of the laterality of the cleft.

Post-surgical complications of supernumerary teeth in the mandibular premolar area: A systematic review

In the mandibular premolar area, supernumerary teeth are a rare disorder that are rarely documented in the literature. The purpose of this study was to evaluate the post-surgical problems associated with the buccal and lingual techniques used to treat the extra teeth in this area. Using PubMed, PubMed Central, Science Direct, Cochrane, Wiley, and manual search, a thorough search was done to locate and identify cases and case series with extra teeth in the mandibular premolar region. For every study that was included, data on the surgical technique and postoperative problems were documented. Seven studies involving 90 patients were included. Supernumerary teeth in the mandibular premolar region were predominantly found in male patients (65.55 %), with most cases occurring in the right mandibular region (77.16 %). Postoperative complications after removing supernumerary teeth using buccal and lingual approaches were similar, with only one complication reported among the 90 cases reviewed. Although the findings suggest that surgical management of supernumerary teeth in the mandibular premolar region is relatively safe, caution is advised due to the limited sample size. Detailed pre-operative evaluation, a comprehensive treatment plan, and regular follow-up can minimize postoperative complications.

Effects of single unilaterally impacted mesiodens on maxillary central incisors: A 3D quantitative assessment based on cone-beam computed tomography

BACKGROUND

Mesiodens usually lead to the malposition and abnormal morphology of maxillary central incisors.

AIM

To evaluate the detrimental effects of single unilaterally impacted mesiodens on the three-dimensional positions and morphology of the maxillary central incisor using cone-beam computed tomographic (CBCT) examinations.

DESIGN

A total of 321 patients aged 5-17 years with single unilaterally impacted mesiodens were included and divided into two groups: mixed dentition group (5-10 years) and early permanent dentition group (11-17 years). CBCT data for these patients were retrospectively analyzed to compare the inclination, rotation, angulation, and morphology of maxillary central incisors between the affected and contralateral control sides. The morphology, orientation, and spatial location of mesiodens were also assessed.

RESULTS

Central incisors on the affected side showed significant palatal crown inclination, shorter root, shorter tooth, and greater crown-to-root ratio in both groups, whereas significant mesial crown angulation was only observed in the mixed dentition group.

CONCLUSION

Impacted mesiodentes result in the displacement and impaired root development of central incisors, strongly suggesting timely clinical management of these abnormal teeth, such as the early removal of mesiodens and orthodontic treatments.

Three-dimensional evaluation of dental characteristics in patients with Cleidocranial dysplasia

BACKGROUND

Cleidocranial dysplasia (CCD) is an autosomal dominant hereditary disorder. Besides skeletal abnormalities, CCD is often associated with dental complications, such as multiple supernumerary teeth and permanent teeth impaction or delayed eruption.

METHODS

Supernumerary teeth of axial, sagittal and coronal CBCT view was characterized in detail and 3D image reconstruction was performed. Number and location of teeth, morphology of supernumerary teeth, positional relationship between supernumerary and adjacent permanent teeth, direction of supernumerary teeth in CCD patients were analyzed.

RESULTS

The mean age of the 3 CCD patients in this study was 16.7 years. Among 36 supernumerary teeth, the majority of them were identified as apical side located and lingual side located. Normal orientation was the most common type in this study, followed by sagittal orientation, and horizontal orientation. Horizontal orientation teeth were all distributed in the mandible. Supernumerary teeth exhibited significantly shorter crown and dental-root lengths, as well as smaller crown mesiodistal and buccolingual diameters (P < 0.01). There was no difference in the number of supernumerary teeth between the maxilla and mandible, and the premolars region had the largest number of supernumerary teeth and the incisor region had the smallest number.

CONCLUSIONS

This study compares number and location of teeth, morphology of supernumerary teeth, positional relationship between supernumerary and adjacent permanent teeth and direction of supernumerary teeth, this study also provides a reference for the comprehensive evaluation of CCD patients before surgery.

On the dentition, tooth replacement, and taxonomic status of Charruodon tetracuspidatus Abdala & Ribeiro, 2000: A bizarre cynodont from the middle upper Triassic of southern Brazil

Among the living tetrapods, mammals present a unique tooth replacement pattern, diphyodonty. Therefore, studying the dentition of mammalian ancestors is relevant to a better understanding of how this remarkable feature evolved. However, little is known about the postcanine tooth replacement pattern among Triassic cynodonts. Here, we applied the nondestructive method of microcomputed tomography (microCT) to analyze the dentition of the enigmatic Upper Triassic sectorial-toothed cynodont Charruodon tetracuspidatus (MCP 3934 PV, holotype) from the Candelaria Sequence, Santa Maria Supersequence, Brazil. The microCT-scan data allowed visualization of the replacement dentition and roots of the functional teeth, which provided information to inform interpretations of the ontogenetic stage and taxonomy of the species. A combination of dental and mandibular traits, as well as the small size of the specimen MCP 3934 PV, suggest an early ontogenetic stage. Additionally, the specimen could potentially be an ontogenetically immature form of another taxon, or a yet unknown species of probainognathian cynodont. Therefore, Charruodon tetracuspidatus is here designated as a nomen dubium, given the challenges of maintaining the species as valid.

Clinical features of non-syndromic late developing supernumerary teeth: a sign of the third dentition?

OBJECTIVES

This study aimed to summarize the clinical features of non-syndromic late developing supernumerary teeth (LDST) and comparisons with common supernumerary teeth (ST) and explore the association between LDST and the third dentition.

MATERIALS AND METHODS

This study retrospected cone-beam computed tomography (CBCT) and medical history of 41,903 consecutive patients from January to December 2021. Comparisons between ST and LDST were evaluated by Chi-square test or Fisher exact test. Correlation between chronological age and dental stage age was evaluated by Spearman's rank correlation coefficient. Binary logistic regression analysis was used to explore the features of LDST originating from the third dentition.

RESULTS

Sixty patients with 126 non-syndromic LDST and 1602 patients with 1988 non-syndromic ST were identified. The prevalence of ST and LDST was 3.82% and 0.14%, respectively, with a male-female ratio of 1.78:1 and 1.31:1. LDST patients mainly had LDST in multiple (58.33%) and bilaterally (41.67%), with an average of 2.1/patient. Most LDST were normal-shaped (84.13%), vertically oriented (71.43%), located in the mandible (80.16%), and distributed in the premolar region (82.54%). The study also indicated that the development of LDST was correlated with permanent teeth, with LDST developing 6.48 to 10.45 years later. In this study, 72.22% of LDST met the clinical criteria for the third dentition.

CONCLUSIONS

LDST manifested different clinical features from common ST. LDST might be closely related to the third dentition.

CLINICAL RELEVANCE

This work would help to comprehend LDST from a clinical perspective, and may be complementary to the criteria of the third dentition.

Supernumerary Tooth Patterns in Non-Syndromic White European Subjects

Supernumerary teeth form at an incidence of about 3% in the population, with differences among races and various clinical consequences. Information on detailed patterns, and especially on white subjects, is scarce in the literature. Therefore, we aimed to investigate the patterns of non-syndromic permanent supernumerary teeth in a white European population. A record review was performed in different orthodontic clinics and identified 207 eligible individuals with 258 supernumerary teeth. Approximately 80% of the subjects had one supernumerary tooth, while 15% had two. Supernumerary tooth formation was more often evident in males (male/female: 1.65). However, there was no sexual dimorphism in its severity. The following pattern sequences, with decreasing prevalence order, were observed in the maxilla: 21 > 11 > 12 > 18 > 28 and in the mandible: 34 > 44 > 35 > 45 > 42. Supernumerary teeth were most often unilaterally present, without sexual dimorphism. In the maxilla, they were more often anteriorly present, whereas in the mandible, an opposite tendency was observed. Supernumerary teeth were consistently more often observed in the maxilla than in the mandible; 74% were impacted, 80% had normal orientation (13% horizontal, 7% inverted), and 53% had normal size. The present thorough supernumerary tooth pattern assessment enables a better understanding of this condition with clinical, developmental, and evolutionary implications.

Ectopic teeth with disparate migration: A literature review and new case series

Purpose

Ectopic eruption can be defined as the emergence of a tooth in an abnormal location, where the tooth does not follow its typical eruption pathway. While ectopic eruption within the dentate region is well-documented in the literature, ectopic eruption in non-dentate regions is relatively rare. This study aimed to report 6 cases of ectopic teeth and present a systematic review of the English-language literature on ectopic teeth, emphasizing demographic characteristics, radiographic features, potential complications, and treatment options.

Materials and Methods

A literature search was conducted using the PubMed, Medline, Web of Science, and Cochrane databases. The demographic data and radiographic findings of patients presenting with ectopic teeth were recorded.

Results

The literature review yielded 61 cases of ectopic teeth, with patients ranging in age from 3 to 74 years. The findings from these previously reported cases demonstrated that the most common location for ectopic teeth was the maxillary sinus, which is consistent with this case series. The Pearson chi-square test was performed to evaluate the correlation between age and location of ectopic teeth, and the results were found to be statistically significant (P<0.05). However, no statistically significant relationship was observed between sex and the location of ectopic teeth.

Conclusion

The distinct features of these cases warrant reporting. This study presents the first case of supernumerary teeth in the condyle without any associated pathosis. Another notable characteristic is the pre-eruptive resorption of 2 inverted supernumerary teeth ectopically located in the palate, which predisposes to sinus opacification.

Extraction of high inverted mesiodentes via the labial, palatal and subperiostal intranasal approach：A clinical prospective study

The aim of this study is to provide criteria for the choice of the surgical approach for extraction of high inverted mesiodens. The operation statistics, life quality of postoperative patients, and the operative injury/recovery were compared and analysed. The laser Doppler blood flowmetry, laser speckle contrast imaging, and electric pulp testing were explored to detect the postoperative pulp and gingiva blood supply of adjacent teeth. For the clinician's primary concerns, the surgical time, the volume of osteotomy, and the amount of bleeding in the labial approach group (The p values are 0.0001, <0.0001, and 0.0131, respectively.) and intranasal approach group (All p values were <0.0001.) were significantly less than that in the palatal approach group. However, from the patient's perspective, the postoperative swelling in the labial approach was far more than that in the intranasal approach group (p =0.0044), with unsurprisingly lower satisfaction (p <0.0001). There were no significant differences in pulp and gingival blood supply of adjacent teeth and jaw development. Trauma was manageable in all patients. Within the limitations of the study it seems that extraction of mesiodens by the intranasal approach achieves a delicate balance between reducing surgical trauma and optimizing postoperative recovery.

Heterozygous Variants in FREM2 Are Associated with Mesiodens, Supernumerary Teeth, Oral Exostoses, and Odontomas

BACKGROUND

Supernumerary teeth refer to extra teeth that exceed the usual number of dentitions. A mesiodens is a particular form of supernumerary tooth, which is located in the premaxilla region. The objective of the study was to investigate the genetic etiology of extra tooth phenotypes, including mesiodens and isolated supernumerary teeth.

METHODS

Oral and radiographic examinations and whole-exome sequencing were performed on every patient in our cohort of 122 patients, including 27 patients with isolated supernumerary teeth and 94 patients with mesiodens. A patient who had multiple supernumerary teeth also had odontomas.

RESULTS

We identified a novel (c.8498A>G; p.Asn2833Ser) and six recurrent (c.1603C>T; p.Arg535Cys, c.5852G>A; p.Arg1951His, c.6949A>T; p.Thr2317Ser; c.1549G>A; p.Val517Met, c.1921A>G; p.Thr641Ala, and c.850G>C; p.Val284Leu) heterozygous missense variants in FREM2 in eight patients with extra tooth phenotypes.

CONCLUSIONS

Biallelic variants in FREM2 are implicated in autosomal recessive Fraser syndrome with or without dental anomalies. Here, we report for the first time that heterozygous carriers of FREM2 variants have phenotypes including oral exostoses, mesiodens, and isolated supernumerary teeth.

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. To investigate the genetic cause of mesiodens, clinical and radiographic examination were performed on 23 family members of a two-generation Hmong family. Whole exome sequencing (WES) or Sanger sequencing were performed in 22 family members and 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.

Rare Genetic Variants in Human APC Are Implicated in Mesiodens and Isolated Supernumerary Teeth

The activation of Wnt/β-catenin signalling is a prerequisite for odontogenesis. APC, a member of the AXIN-CK1-GSK3β-APC β-catenin destruction complex, functions to modulate Wnt/β-catenin signalling to establish regular teeth number and positions. APC loss-of-function mutations are associated with the over-activation of WNT/β-catenin signalling and subsequent familial adenomatous polyposis (FAP; MIM 175100) with or without multiple supernumerary teeth. The ablation of Apc function in mice also results in the constitutive activation of β-catenin in embryonic mouse epithelium and causes supernumerary tooth formation. The objective of this study was to investigate if genetic variants in the APC gene were associated with supernumerary tooth phenotypes. We clinically, radiographically, and molecularly investigated 120 Thai patients with mesiodentes or isolated supernumerary teeth. Whole exome and Sanger sequencing identified three extremely rare heterozygous variants (c.3374T>C, p.Val1125Ala; c.6127A>G, p.Ile2043Val; and c.8383G>A, p.Ala2795Thr) in APC in four patients with mesiodentes or a supernumerary premolar. An additional patient with mesiodens was compound as heterozygous for two APC variants (c.2740T>G, p.Cys914Gly, and c.5722A>T, p.Asn1908Tyr). Rare variants in APC in our patients are likely to contribute to isolated supernumerary dental phenotypes including isolated mesiodens and an isolated supernumerary tooth.

Identification of a novel missense mutation in non-syndromic familial multiple supernumerary teeth

OBJECTIVE

This study intended to evaluate the involvement of genetic factors in the etiology of non-syndromic multiple supernumerary teeth.

DESIGN

We filtered the single nucleotide polymorphisms (SNPs) of the proband and his mother with similar phenotypes through whole-genome sequencing (WGS). By integrating multiple databases related to human genome mutations and disease information for mutation annotation, we excluded the SNPs of people without supernumerary teeth. Subsequently, the bioinformatics analysis tools (Sorting Intolerant From Tolerant (SIFT) < 0.05, Polymorphism Phenotyping (PolyPhen) > 0.90) were used to screen out the most correlated SNPs of the disease, besides, Gene Ontology (GO) analysis (P<0.05, FDR<0.05) and Sanger sequencing was applied to further verify the candidate pathogenic mutation point.

RESULTS

A novel heterozygous variant in fer-1 like family member 6 (FER1L6) gene likely denoted pathogenicity in non-syndromic familial multiple supernumerary teeth. We identified a cohort of 3499 non-synonymous SNPs (nsSNPs), and only 142 nsSNPs with the score of SIFT < 0.05 and PolyPhen > 0.90 were retained. Then we got 54 nsSNPs from 31 candidate genes through GO analysis. Sanger sequencing revealed a missense variant in exon 31 of the FER1L6 gene, causing a transition from guanine to adenine in position 1447 of protein kinase C conserved region 2.

CONCLUSIONS

We identified a novel heterozygous chromosome 8q24.13 mutation of FER1L6, which was a new mutation site identified in non-syndromic familial multiple supernumerary teeth through genetic analysis of a Chinese family.

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.

Assessment of risk factors and molecular biomarkers in children with supernumerary teeth: a single-center study

Background

Supernumerary teeth are considered one of the commonly observed dental anomalies in children. Several theories have been proposed to explain the presence of supernumerary teeth, including environmental and genetic factors. This study aimed to identify the different risk factors and molecular biomarkers in patients presented with supernumerary teeth.

Methods

This case–control study included 240 children, 6 to 12-year-old. They were divided into a test group (n = 120 children presented with supernumerary teeth) and a control group (n = 120 children with no supernumerary teeth). Questionnaires were distributed to assess demographics and exposure to several environmental factors. Ten extracted supernumerary teeth from the test group were processed for histopathological analysis.

Results

Male gender, dental history of severe oral infection or medical history of chemotherapy treatment, previous history of taking medication or illness during pregnancy, family history of neoplastic disorders, use of electronic devices, and living beside agricultural fields or industrial areas were found to be statistically significant associated with the risk of supernumerary teeth development. Immunohistochemistry panel revealed that supernumerary teeth showed enhanced expression of wingless (Wnt) and sonic hedgehog (SHH) proteins as well as a reduced expression of adenomatous polyposis coli (APC) protein, denoting molecular derangement in a group of pathways classically believed to be involved in its pathogenesis.

Conclusions

Males were more frequently affected by supernumerary teeth than females. Several risk factors were notably correlated with the existence of supernumerary teeth. Additionally, molecular biomarkers assessment demonstrated a high expression level of pro-tumorigenic proteins such as Wnt and SHH in patients with supernumerary teeth.

The Human Genetics of Dental Anomalies

The development of tooth is a highly complex procedure and mastered by specific genetic programs. Genetic alterations, environmental factors, and developmental timing can disturb the execution of these programs, and result in various dental anomalies like hypodontia/oligodontia, and supernumerary teeth, which are commonly seen in our clinical practice. Advances in molecular research enabled the identification of various genes involved in the pathogenesis of dental anomalies. In the near future, it will help provide a more accurate diagnosis and biological-based treatment for these anomalies. In this article, we present the molecular phenomenon of tooth development and the genetics of various dental anomalies.

Ancient anomalies: Twinned and supernumerary incisors in a medieval Nubian

During the analysis of a skeletal assemblage from a medieval cemetery in Nubia (c. AD 500-1550), a young adult female with abnormally developed maxillary incisors was discovered. The possible causes of the two dental anomalies found in this individual and their archaeological context are discussed. The remains are from a medieval assemblage from the Fourth Cataract region of Nubia, which forms part of the Nubian collection curated at the British Museum. The left central incisor has a twinned crown with two root canals, and a supernumerary tooth is present on the right side between the central incisor and lateral incisors. Although two different dental anomalies are present, the bilateral expression suggests that the same biological mechanism could be responsible.

Evolutionary implications of dental anomalies in bats

The gain or loss of anatomical features is an important mechanism of morphological evolution and ecological adaptation. Dental anomalies-the loss or gain of teeth-are widespread and a potential source of craniodental specialization among mammals, yet their macroevolutionary patterns have been rarely explored. We present the first phylogenetic comparative study of dental anomalies across the second largest mammal Order, Chiroptera (bats). We conducted an extensive literature review and surveyed a large sample of museum specimens to analyze the types and prevalence of dental anomalies across bats, and performed phylogenetic comparative analyses to investigate the role of phylogenetic history and dietary specialization on incidence of dental anomalies. We found dental anomalies have a significant phylogenetic signal, suggesting they are not simply the result of idiosyncratic mutations or random developmental disorders, but may have ancestral genetic origins or result from shared developmental pathways among closely related species. The incidence of dental anomalies was not associated with diet categories, suggesting no effect of craniodental specialization on dental anomalies across bats. Our results give insight into the macroevolutionary patterns of dental anomalies in bats, and provide a foundation for investigating new hypotheses underlying the evolution of dental variation and diversity in mammals.

Prevalence of hyperdontia, hypodontia, and concomitant hypo-hyperdontia

Background/purpose

Anomalies in human dentition are some of the most common occurrences of congenital abnormalities. Present study aimed to determine the prevalence of hypodontia, hyperdontia and concomitant hypo-hyperdontia (CHH) among patients attending the University of Nevada, Las Vegas (UNLV) School of Dental Medicine clinics.

Materials and methods

Retrospective search was conducted on patients’ clinical notes in AxiUm™. Search included using keywords such as “hypodontia”, “hyperdontia”, “supernumerary teeth” and “congenitally missing”. Panoramic radiographs were used to confirm the hyperdontia, hypodontia or CHH for patients attending the UNLV SDM clinics from 2010 to 2018. Collected data were analyzed using the chi-square test.

Results

1101 patients were populated using the keywords. From these populated patients, 186 had hyperdontia, 23 hypodontia, and 3 presented with CHH. The distribution of males and females was 54.7% and 45.3% respectively. Hispanics, African Americans, Asians, Caucasians and ethnically unspecified patients represented 43.39%, 14.25%, 3.30%, 8.02%, and 31.13%, respectively, of those patients with a dental anomaly. Hyperdontia was most common amongst Hispanic patients with 39.24%, followed by the unspecified patients at 32.8% as well as amongst males at 56.45% (P value of 0.03). Unidentifiable supplemental teeth were overall the greatest in number with the lower right premolars, tooth 44, being the most common. This was demonstrated in the Hispanic patients whereas within the African American patients a 4th molar was in excess.

Conclusion

Hispanic patient population has a significant link to dental anomalies, specifically hyperdontia while the presence of the fourth molar was prominent among African American patients.

Oncostatin M enhances osteogenic differentiation of dental pulp stem cells derived from supernumerary teeth

Supernumerary tooth (ST) may arise from uncertain developmental abnormalities or underlying genetic causes, and the extraction at the early age is recommended. Dental pulp stem cells (DPSCs) are the valuable resource for the regeneration of tooth and related craniofacial structures. DPSCs isolated from ST (sDPSCs) have not been fully characterized despite the potential in the applications. The objectives of this study are the efficient isolation of sDPSCs and the analysis of the properties as stem cells. sDPSCs were established by hammer-cracking and separation of the intact pulp from ST. sDPSCs in the culture were examined by light microscope and flow cytometer for the morphology and the surface marker expression. sDPSCs exhibited the cellular morphology of typical mesenchymal stem cells and expressed CD44, CD73, CD90, CD105 and CD166, but not CD14, CD34 or CD45. sDPSCs showed the differentiation potential toward osteogenic, chondrogenic and adipogenic lineages. During osteogenic differentiation, the stimulation by Oncostatin M enhanced the differentiation and significantly increased the expression of genes involved in the hard tissue repair, such as BMP2, BMP4, BMP6 and RUNX2. sDPSCs can be effectively derived from ST and displays the characteristics of mesenchymal stem cells in the maintenance and the differentiation. sDPSCs satisfies the quality as DPSCs thus provide the valuable resource to the regenerative therapy.

Process of ectopic tooth formation in the maxillary sinus: follow-up observation of one case

Objective

This study was performed to investigate the process of ectopic tooth formation.

Methods

A patient with an ectopic tooth was followed for 6 years. The tooth size and mineralization were evaluated by paranasal sinus computed tomography every 3 years.

Results

The ectopic tooth was present in the nasal crest of the maxilla and did not change significantly during the 6-year follow-up period. However, the patient developed a new ectopic tooth in the maxillary sinus (ETm). This tooth, located in the posterior wall of the left maxillary sinus, initially appeared as a small region of soft tissue on computed tomography. After 3 years, the area of mixed density had significantly increased, and some of it had significantly mineralized to form an ETm. After 6 years, the ETm had further mineralized and enlarged in situ. The width between the left and right sides of the ETm in 2018 (9.08 ± 2.09 mm) was significantly larger than that in 2015 (7.51 ± 2.18 mm), indicating that ETm formation is a gradual process of mineralization.

Conclusion

Ectopic teeth can gradually form by in situ mineralization after adolescence, suggesting that ectopic teeth are genetically regulated and result from a programmed formation process occurring at a specific time point.

Prevalence and presentation of hyperdontia in a non-syndromic, mixed Nigerian population

BACKGROUND

Although there have been studies on the prevalence and pattern of hyperdontia in sub-Saharan African subjects with similar cultural backgrounds, based on our search, none have been able to consider these epidemiological parameters in a multiethnic black population, which is expected to add substantial knowledge to what is available.

MATERIAL AND METHODS

This is a retrospective study on the panoramic radiographs of subjects who presented at two dental centres in Abuja, Nigeria between June 2013 and June 2018. Radiographic interpretations were carried out by three independent observers, trained on computer assisted radiographic image interpretation. Data were collected and analyzed using Statistical package for the Social sciences (SPSS) version 22 (IBM Corp, Armonk, USA).

RESULTS

One thousand eight hundred and thirty seven (1837) panoramic radiographs were studied. Subject comprised males and females between ages 12 - 95 years with an average of 35.0 years. The prevalence of unilateral hyperdontia was 1.47% while an occurrence rate of 0.27 was observed for bilateral and multiple hyperdontia. For maxillary hyperdontia, a prevalence of 1.09% was recorded which was significantly more common than the mandibular type (0.65). Of note is that all the supernumerary teeth types were commonly observed in the maxilla except the parapremolar type, with a mandibular occurrence rate of 76.9%.

CONCLUSIONS

From this study, we can conclude that the prevalence of hyperdontia (across different black ethnicities) is low. Although, follicular epithelium around the tooth and root resorption of the enlargement around the adjacent teeth was observed, most were asymptomatic (87.0%) and required no intervention. Key words:Hyperdontia, panoramic radiographs, Sub-Saharan Africa, supernumerary teeth.

Non-syndromic cleft lip with or without palate-susceptible SNPs is associated with hyperdontia

BACKGROUND

Non-syndromic supernumerary teeth (NSST) or hyperdontia may share common genetic determinants with non-syndromic cleft lip with or without palate (NSCL/P). The aim of this study was to test the associations between five genome-wide-associated NSCL/P-susceptible single nucleotide polymorphisms (SNPs) (rs2235371, rs7078160, rs8049367, rs4791774, and rs13041247) and the occurrence of NSST.

MATERIALS AND METHODS

A total of 163 cases and 326 controls were recruited and their genomic DNA was extracted from blood samples. Five NSCL/P-susceptible SNPs (rs2235371, rs7078160, rs8049367, rs4791774, and rs13041247) were genotyped by TaqMan method. Odds ratio (OR) and 95% confidence interval (CI) were used to estimate the associations between the SNPs and the risk of NSST by PLINK software.

RESULTS

Rs4791774 (A > G) and rs13041247 (T > C) were associated with risk of NSST (rs4791774: P_add  = 0.011, OR, 95% CI = 0.62, 0.43-0.90; rs13041247: P_homo  = 0.031, OR, 95% CI = 1.79, 1.05-3.05) and one supernumerary tooth (rs4791774: P_dom  = 0.009, OR, 95% CI = 0.56, 0.36-0.87; rs13041247: P_homo  = 0.034, OR, 95% CI = 1.82, 1.05-3.15). Rs4791774 (A > G) was also showed association with risk of upper arch supernumerary teeth only (P_add  = 0.010, OR, 95% CI = 0.60, 0.41-0.89).

CONCLUSION

Non-syndromic cleft lip with or without palate-susceptible loci rs4791774 (A > G) and rs13041247 (T > C) were associated with the risk of supernumerary teeth.

A Review of Supernumerary Teeth in the Premolar Region

Supernumerary teeth in the premolar region, unlike other supernumeraries, occur more often in the mandible where they are generally of the supplemental type. Occasionally, they are conical or smaller than normal, particularly in the upper premolar regions. They might occur singly or in multiples, be erupted or impacted, but the majority have been found to be unerupted and asymptomatic. The prevalence of supernumerary teeth in the premolar region has been demonstrated to be between 0.01 and 1 percent depending on the population studied. Interestingly, populations from the East or Africa are known to be the most affected. Various theories have been suggested to explain the etiology of supernumerary teeth in general including both genetic and environmental factors. Furthermore, it has been suggested that supernumerary premolar teeth belong to a third (postpermanent) series, developing from extensions of the dental lamina. Several consequences can result from the presence of supernumerary premolars, especially in the mandible, such as cyst formation, transposition, and other clinical scenarios.

Dental Abnormalities and Oral Pathology of the Pataud 1 Upper Paleolithic Human

We have re-evaluated the dental abnormalities and oral pathology evident on the Mid-Upper Paleolithic Pataud 1 skeleton, including additional remains recently excavated for this individual, in an effort to expand current knowledge of Pleistocene human paleopathology, in light of current clinical and paleopathological assessments of oral variation and diseases. The young adult female Pataud 1 presents an impacted right M3, widespread periodontitis, large retromolar voids, double right maxillary supernumerary (paramolar) teeth, and new bone deposition on the medial mandibular rami and posterior maxillae. The Pataud 1 remains thus join a substantial sample of Pleistocene humans with congenital/developmental abnormalities, some of which (as in Pataud 1) consequently resulted in secondary abnormalities. M3impaction and supernumerary teeth are known in a couple of other Mid-Upper Paleolithic individuals, and mild to moderate periodontal disease appears to have been widespread. However, such marked resorption of the alveolar margin in a young adult is unusual, and the secondary inflammation (possibly septicemia) leading to new bone deposition is otherwise unknown in the sample and may have led to her death.

Investigation of SOSTDC1 gene in non-syndromic patients with supernumerary teeth

Background

The etiology of supernumerary teeth is still unclear however heredity is believed to be a major factor and this idea was supported by several case reports. Recently, a relationship between supernumerary tooth formation and deficiency of Uterine Sensitization Associated Gene-1 (Usag-1), a rat gene that is expressed in sensitized endometrium, was reported in mice. The human homolog gene for Usag-1, Sclerostin Domain Containing 1 (SOSTDC1), shows 85% identity with mouse Usag-1. The present study aimed to investigate SOSTDC1 coding regions in non-syndromic patients with one or more supernumerary teeth.

Material and Methods

Twenty-five non-syndromic patients (21 male and 4 female) aged 5-15 years, with one or more supernumerary teeth were included in the study. Saliva samples were collected from patients and DNA samples were isolated and analyzed using PCR.

Results

Eight phenotypes of supernumerary tooth formation were observed in the study. From the DNA analysis, 2 novel and 3 previously identified sequence alterations were identified however, in investigating the Usag-1 homolog SOSTDC1 gene, the present study could not find any phenotype-genotype relationship.

Conclusions

There are many SOSTDC1 homolog genes in the human genome and future studies should investigate these candidate genes. Also studies in larger case groups including family members may reveal the hereditary pattern.

Key words:Genetics, Usag-1, mesiodens, DNA sequencing, pediatric dentistry, PCR.

Nonsyndromic Bilateral Posterior Maxillary Supernumerary Teeth: A Report of Two Cases and Review

Supernumerary tooth/hyperdontia is defined as those teeth which are present in excess of the usual distribution of twenty deciduous and thirty-two permanent teeth. It can be seen in both syndromic and nonsyndromic patients. In Nepalese population, prevalence of supernumerary tooth is documented to be 1.6%. To the best of our knowledge, no studies from Nepal have reported the incidence of bilateral maxillary paramolars or the combination of unilateral maxillary paramolar and distomolar till date. Hence, we are reporting these two cases with a brief review of literature to put emphasis on incidence, prevalence, proposed hypothesis for etiology, and management of supernumerary teeth.

Supernumerary Molars and Wisdom Tooth Shape Alterations in Patients with Neurofibromatosis Type 1

Objectives

The purpose of the present study was the systematic investigation of numerical and morphological aberrations of teeth in the wisdom teeth region in neurofibromatosis type 1 patients.

Material and Methods

The panoramic radiographs of 179 patients were analysed for supernumerary molars and dysplastic wisdom teeth with special reference to facial tumour type. The results were compared to radiographic findings obtained in panoramic radiographs of age- and sex-matched controls.

Results

The total number of dysplastic or supernumerary molars was 21 (17 individuals, 4.75%) and predominantly a finding of the maxilla (maxilla: 15, mandible: 1, maxilla and mandible: 1). Differences of dental findings between neurofibromatosis type 1 (NF1) patients (n = 15) and the control group (n = 2) were statistically significant (P < 0.01). All individuals with supernumerary molars were diagnosed as being affected with NF1. This difference achieved statistical significance when it was considered that the event may occur at least once per quadrant, and thus the individual potentially needs to be considered four times (P = 0.0038).

Conclusions

This investigation revealed that supernumerary molars and aberrations in wisdom tooth form are more common in patients than in age- and sex-matched controls. There is no association between these findings and a specific feature of the disease, id est facial manifestation of a trigeminal nerve sheath tumour (plexiform neurofibroma). The cause of this phenomenon is unknown. A review of these dental findings on other neurofibromatosis type 1 study groups should be attempted.

Genetic basis of dentigerous cysts associated with supernumerary teeth: A narrative review

In the present study, we sought to: (a) analyze the p53 gene status in dentigerous cysts (DC) associated with supernumerary teeth (ST) in a pair of siblings with ST, of whom one developed a DC; and (b) conduct a narrative review of the literature on ST associated with DC. Blood samples were obtained, and the isolated DNA was used to amplify exons 4-8 of the p53 gene using specific primers, and subsequently sequenced. No mutations were identified in the coding regions of the p53 gene. A review of the literature revealed a prevalence of DC associated with ST to be as high as 13.6%, and that 83% of the case reports performed enucleation of DC and removal of ST. Dentigerous cysts associated with ST in one sibling demonstrated that variations in phenotypes exist, and the absence of mutations cannot eliminate the potential influence of genetic risk factors.

Favorable outcome of a maxillary supplemental premolar

Hyperdontia/additional teeth are the commonly used synonyms for supernumerary tooth/teeth (ST). They occur due to the disturbances during the initiation stage of tooth development. They can be noticed in any region of oral cavity and may be single, double, or multiple; unilateral or bilateral; erupted or unerupted. This report presents a case of impacted single ST in the maxillary premolar region in a 14-year-old boy. Usually, ST are extracted, but there are some conditions where ST could be used beneficially. The present case is an example where ST played a beneficial role.

A novel mutation of adenomatous polyposis coli (APC) gene results in the formation of supernumerary teeth

Supernumerary teeth are teeth that are present in addition to normal teeth. Although several hypotheses and some molecular signalling pathways explain the formation of supernumerary teeth, but their exact disease pathogenesis is unknown. To study the molecular mechanisms of supernumerary tooth‐related syndrome (Gardner syndrome), a deeper understanding of the aetiology of supernumerary teeth and the associated syndrome is needed, with the goal of inhibiting disease inheritance via prenatal diagnosis. We recruited a Chinese family with Gardner syndrome. Haematoxylin and eosin staining of supernumerary teeth and colonic polyp lesion biopsies revealed that these patients exhibited significant pathological characteristics. APC gene mutations were detected by PCR and direct sequencing. We revealed the pathological pathway involved in human supernumerary tooth development and the mouse tooth germ development expression profile by RNA sequencing (RNA‐seq). Sequencing analysis revealed that an APC gene mutation in exon 15, namely 4292‐4293‐Del GA, caused Gardner syndrome in this family. This mutation not only initiated the various manifestations typical of Gardner syndrome but also resulted in odontoma and supernumerary teeth in this case. Furthermore, RNA‐seq analysis of human supernumerary teeth suggests that the APC gene is the key gene involved in the development of supernumerary teeth in humans. The mouse tooth germ development expression profile shows that the APC gene plays an important role in tooth germ development. We identified a new mutation in the APC gene that results in supernumerary teeth in association with Gardner syndrome. This information may shed light on the molecular pathogenesis of supernumerary teeth. Gene‐based diagnosis and gene therapy for supernumerary teeth may become available in the future, and our study provides a high‐resolution reference for treating other syndromes associated with supernumerary teeth.

The epidemiology of supernumerary teeth and the associated molecular mechanism

Supernumerary teeth are common clinical dental anomalies. Although various studies have provided abundant information regarding genes and signaling pathways involved in tooth morphogenesis, which include Wnt, FGF, BMP, and Shh, the molecular mechanism of tooth formation, especially for supernumerary teeth, is still unclear. In the population, some cases of supernumerary teeth are sporadic, while others are syndrome-related with familial hereditary. The prompt and accurate diagnosis of syndrome related supernumerary teeth is quite important for some distinctive disorders. Mice are the most commonly used model system for investigating supernumerary teeth. The upregulation of Wnt and Shh signaling in the dental epithelium results in the formation of multiple supernumerary teeth in mice. Understanding the molecular mechanism of supernumerary teeth is also a component of understanding tooth formation in general and provides clinical guidance for early diagnosis and treatment in the future.

Dental anomalies: prevalence and associations between them in a large sample of non-orthodontic subjects, a cross-sectional study

Background

To analyze the prevalence and associations between dental anomalies detectable on panoramic radiographs in a sample of non-orthodontic growing subjects.

Methods

For this cross-sectional study, digital panoramic radiographs of 5005 subjects were initially screened from a single radiographic center in Rome. Inclusion criteria were: subjects who were aged 8–12 years, Caucasian, and had good diagnostic quality radiographs. Syndromic subjects, those with craniofacial malformation, or orthodontic patients were excluded and this led to a sample of 4706 subjects [mean (SD) age = 9.6 (1.2) years, 2366 males and 2340 females]. Sample was subsequently divided into four subgroups (8, 9, 10, and 11–12 year-old groups). Two operators examined panoramic radiographs to observe the presence of common dental anomalies. The prevalence and associations between dental anomalies were also investigated.

Results

The overall prevalence of dental anomalies was 20.9%. Approximately, 17.9% showed only one anomaly, 2.7% two anomalies, while only 0.3% had more than two anomalies. The most frequent anomalies were the displacement of maxillary canine (7.5%), hypodontia (7.1%), impacted teeth (3.9%), tooth ankylosis (2.8%), and tooth transposition (1.4%). The lower right second premolar was the most frequent missing teeth; 3.7% had only one tooth agenesis, and 0.08% had six or more missing tooth (Oligodontia). Mesiodens was the most common type of supernumerary tooth (0.66%). Two subjects had taurodontic tooth (0.04%). Tooth transpositions and displacement of maxillary canine were seen in 1.4 and 7.5%, retrospectively (approximately 69 and 58% were in the 8 and 9 year-old groups, retrospectively). Significant associations were detected between the different dental anomalies (P < .05).

Conclusions

The results of our study revealed significant associations among different dental anomalies and provide further evidences to support common etiological factors.

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-017-0352-y) contains supplementary material, which is available to authorized users.

Professional dental prophylaxis increases salivary cortisol in children with dental behavioural management problems: a longitudinal study

Background

Dental procedures may cause stress and increase the salivary cortisol levels. It is important to known if apparently simple procedures such as professional dental prophylaxis at low speed (DP) are stressful for children with dental behaviour management problems (DBMP) to help with behaviour guidance strategies. This longitudinal study aimed to evaluate if DP changes a physiological marker of stress (salivary cortisol) in children with DBMP who were referred to dental treatment under sedation.

Methods

One paediatric dentist carried out a DP with rubber cup and pumice followed by dental examination in 39 children aged 2–5 years, prior to the dental sedation appointment. Children’s saliva was collected at three different moments: upon waking (UW), on arrival at the dental office reception area (RA) and 25 min after the dental prophylaxis (DP). The saliva samples were analysed using an enzyme immunoassay kit. The Wilcoxon test was used in paired comparison (P < 0.05).

Results

Salivary cortisol levels decreased from UW (0.34; 0.15–0.54) to RA (0.14; 0.08–0.56) (P = 0.019) and increased from RA to DP (0.25; 0.06–1.48) (P = 0.008). Higher salivary cortisol levels were observed at DP when compared to RA in children who did not have previous dental treatment (P = 0.007), had toothache (P = 0.006), presented some protest behaviour during DP (P = 0.008), or needed protective stabilisation by parents for the dental examination (P = 0.005).

Conclusions

Paediatric dentists should be aware that even simple procedures such as professional dental prophylaxis are related to stress in young children.

Genetic background of supernumerary teeth

Supernumerary teeth (ST) are odontostomatologic anomaly characterized by as the existence excessive number of teeth in relation to the normal dental formula. This condition is commonly seen with several congenital genetic disorders such as Gardner's syndrome, cleidocranial dysostosis and cleft lip and palate. Less common syndromes that are associated with ST are; Fabry Disease, Ellis-van Creveld syndrome, Nance-Horan syndrome, Rubinstein-Taybi Syndrome and Trico–Rhino–Phalangeal syndrome. ST can be an important component of a distinctive disorder and an important clue for early diagnosis. Certainly early detecting the abnormalities gives us to make correct management of the patient and also it is important for making well-informed decisions about long-term medical care and treatment. In this review, the genetic syndromes that are related with ST were discussed.

Idiopathic resorption of impacted mesiodentes: a radiographic study

BACKGROUND

Although a large number of mesiodentes are left in situ, only a few are found in radiographs from epidemiological studies of adult populations. This leads to the development of a hypothesis that mesiodentes may be resorbed and disappear over time. The aim of this study was to radiographically investigate the frequency of resorptions and pathologies in relation to mesiodentes left in situ.

METHODS

The study population consisted of 44 individuals, with 49 mesiodentes left in situ at an early age. The individuals were 18-38 years old when re-examined. The inclusion criteria were that the mesiodentes had been diagnosed in childhood and left in situ, and that each individual was over 18 years of age at the time of re-examination. Either digital or analogue intraoral radiographs were used at the re-examination and compared with earlier analogue radiographs.

RESULTS

Forty-one per cent of the impacted mesiodentes showed resorptions-from limited to nearly complete resorption. No pathologies in connection to the mesiodentes were found.

CONCLUSION

About half of the mesiodentes examined displayed resorption. No pathologies caused by the mesiodentes were recorded.

Psychometric and biohormonal indices of dental anxiety in children. A prospective cohort study

The stress of dental treatment often elicits negative emotions in children, expressed as dental fear or anxiety. Highly anxious children obstruct treatment and avoid therapy, further amplifying oral health problems. The aim of this study was to examine the neuroendocrine and autonomic nervous system responses to dental treatment and their possible interactions and associations with psychometric indices of anxiety, caries, previous dental experience, anesthesia, age and gender in school children. Upon informed consent, saliva was obtained from 97 children (59% males, mean age ±  SD: 89.73 ± 15 months) in the Clinic of pediatric dentistry before treatment, immediately post-treatment and at the recall visit to determine cortisol and salivary alpha-amylase (sAA) levels. Dental and general anxiety was assessed through specific questionnaires completed by the children. Compared to pre-treatment, cortisol levels were increased following treatment, while sAA levels were higher at the recall. Pre- and post-treatment cortisol and sAA responses were positively correlated. Dental and general anxiety questionnaire scores were also significantly correlated with each other. The integrated autonomic and neuroendocrine responses prior to treatment were correlated with state anxiety and those following treatment with dental anxiety. However, univariable and multivariable linear regression analysis associated post-treatment cortisol, but not sAA, levels with dental anxiety. No associations of cortisol or sAA responses with caries, age, gender, previous dental experience or anesthesia were detected. These data provide some evidence that both sAA and cortisol levels are altered in children in anticipation or during dental treatment, but only cortisol levels are associated to dental anxiety.