Potential Association of Molar-Incisor Hypomineralization (MIH) with Dental Agenesis and Infraoccluded Deciduous Molars: Is MIH Related to Dental Anomaly Pattern (DAP)? An Observational Cross-Sectional Study

Background: Dental Anomaly Pattern (DAP) is a collection of morphologic, numeric, and eruptive anomalies of teeth that are often observed together, suggesting a potential genetic relationship. Our objective was to assess the potential associations of Molar-Incisor Hypomineralization (MIH), a common developmental defect of enamel mineralization with a controversial etiology, with two specific components of DAP: (1) agenesis (AG) and (2) infraoccluded deciduous molars (IODM). Establishing such an association between MIH and one or both anomalies would provide evidence supporting a genetic link between MIH and DAP. Methods: We examined pretreatment intraoral standardized photographies and panoramic radiographs from 574 children aged 8-14 years, 287 having MIH and 287 without MIH, comparing the frequencies of AG and IODM in both groups. The subject samples were sourced from the databases of the orthodontic department at a university hospital. Results: The frequencies of AG in the MIH and non-MIH groups were 7% and 8%, respectively (p = 0.751). The corresponding frequencies of IODM were 27% and 19.2%, respectively (p = 0.082). That is, children with MIH did not exhibit an increased frequency of AG or IODM compared to those without MIH. Conclusions: These findings do not support the inclusion of MIH in DAP. Nevertheless, further analysis of possible associations is necessary to definitively validate or invalidate this hypothesis.

The Prevalence of Congenitally Missing Permanent Teeth in a Sample of Orthodontic and Non-Orthodontic Caucasian Patients

BACKGROUND

Hypodontia represents a notable clinical and public health concern.

OBJECTIVE

To assess the prevalence of congenitally missing permanent teeth in a sample of orthodontic/dental patients of Caucasian origin originating from the Greek island of Lesvos.

MATERIALS AND METHODS

Panoramic X-rays from 621 children and adolescents, aged 9 to 16 years (average age 12.5 years), 521 seeking orthodontic care (orthodontic group) and 100 seeking dental care (non-orthodontic group) were examined to identify congenitally missing permanent teeth.

RESULTS

The orthodontic group exhibited a 5.5% prevalence of congenitally missing permanent teeth (2.8% females; 2.7% males), while the non-orthodontic group showed a prevalence of 4% (3% females; 1% males). The descending order of prevalence for missing tooth types was as follows: lower second premolars, upper laterals, lower central incisors, lower canines, upper second premolars, and lower second molars. Among orthodontic patients with missing teeth, 62% presented with an Angle's Class II malocclusion. Hypodontia was most frequently observed in the mandible. No statistically significant differences were observed between the orthodontic and non-orthodontic groups in terms of the percentage of children and types of congenitally missing teeth.

CONCLUSIONS

Congenitally missing teeth were observed in about 4-5% of the studied population with a female predilection. The lower second premolar was the most commonly absent tooth, followed by the maxillary lateral incisors. An Angle's Class II malocclusion was present in the majority of orthodontic patients with hypodontia, mostly in the mandible.

Mandibular Second Premolar Agenesis: A Retrospective Cross-sectional Study from Palestine

Objectives

This retrospective study aimed to determine the prevalence of congenitally missing mandibular second premolars.

Materials and Methods

A total of 1,843 radiographs were collected from five different cities in Palestine. Two experienced dentists independently examined the panoramic radiographs and demographic data (age and gender).

Results

Among the 1,843 radiographs, 1,039 were for females (57.37%) and 804 were for males (43.63%); 13 cases had at least one congenitally mandibular second premolar. The prevalence of congenitally missing mandibular second premolars in the study population was 0.7%. There was no significant association between gender and mandibular second premolar agenesis. Unilateral agenesis was more common than bilateral, and the left side had more cases of congenitally missing mandibular second premolars than the right side.

Conclusions

The prevalence of congenitally missing mandibular second premolars in this study population was 0.7%, within the range reported in other populations.

Three-dimensional changes in the cranial base associated with soft-diet feeding

BACKGROUND

Masticatory activity affects the morphology of the maxillo-mandibular complex, however, its influence on the cranial base remains to be elucidated. The recent integration of quantitative morphometric analysis with 3D imaging enabled a comprehensive and high-resolution morphological characterization of the craniofacial complex. We aimed to investigate the influence of masticatory activity on the morphology of the growing cranial base by three-dimensional (3D) geometric morphometric approach using micro-CT.

METHODS

The micro-CT data was reanalyzed to illustrate the 3D shape of the cranial base, and wireframe models were generated by connecting landmarks on the images. In the original study, mice were fed a soft diet (SD) of powdered pellets or a conventional hard diet (HD) for 6 weeks from 3 to 9 weeks of age, immediately after weaning. A principal component (PC) analysis analyzed shape variations and assessed their significance, while canonical variate (CV) analysis facilitated the comparison and differentiation of groups based on shape, unveiling meaningful shape distinctions.

RESULTS

Three PCs were extracted that significantly separated the SD and HD groups among those explaining variations in shape. These PCs were related to the length of the sphenoid bone, the width of the anterior part of the sphenoid bone, and the length of the cranial base. Furthermore, one CV effectively distinguished SD from HD, and CV analysis showed that the sphenoid was shortened in the length and narrowed at the border of the temporal bone in SD mice.

CONCLUSIONS

Masticatory loading affects the skeletal development of the cranial base. The morphology of the sphenoid bone was affected in both the sagittal and transverse axes.

Rare Pediatric Genetic Case Report of X-linked Hypohidrotic Ectodermal Dysplasia Type 1

Ectodermal dysplasia (ED) is a rare disorder that appears differently in clinical cases and can present with a variety of combinations and severities of abnormalities that can involve a variety of tissues. The disease might appear clinically as hypotrichosis, hypohidrosis, or hypodontia, among other clinical manifestations. The patient, a five-year-old boy, was seen at the Taibah University Dental Clinic and was diagnosed with X-linked hypohidrotic ectodermal dysplasia type 1 based on clinical radiographic and genetic findings. Although there is no base data for reporting this case, the present case presentation could alert dental practitioners and expand scientific database knowledge on the dental and/or oral characteristics of this abnormality.

Rehabilitation with implant-supported overdentures in preteens patients with ectodermal dysplasia: A cohort study

INTRODUCTION

Hypohidrotic ectodermal dysplasia (HED) patients suffering of oligo-anodontia require early dental treatment to improve oral functions and reduce social impairment. The aim of this study was to evaluate the skeletal growth, implant and prosthetic survival rate, success, and complications after the rehabilitation with a maxillary denture and an implant-supported overdenture provided by a sliding bar in case of severe hypodontia/anodontia related to HED.

MATERIALS AND METHODS

This retrospective cohort study began in 2009. Nine patients over 7 years old with HED and associated oligo-anodontia who presented at the University of Bologna for dental treatment were included in the study. They were first treated with conventional dentures and then with a maxillary denture and an implant-supported overdenture with a sliding bar connected to two implants placed in the anterior mandible. The subjects treated were followed for 3-12 years. In each case, orthopanoramic and lateral cephalometric radiographic exam were taken before implant placement and annually after prosthetic load. Vertical and transverse dimensions of the mandible in the symphysis area at implant sites were taken on the lateral cephalometric radiography at the time of implant placement and after 5 years from the prosthetic loading to assess the presence or absence of an anterior mandibular growth. Biologic and mechanical complications were also recorded at every visit.

RESULTS

A mandibular vertical growth under the implant apex, at the implant neck, and a sagittal growth of the symphysis after 5 years from the prosthetic loading were observed and measured. Implant and prosthetic success and survival rates were 100% after 8.1 years (mean) follow-up period. No complications were reported except in one patient, where the repositioning of a retentive cap on the counter bar in the superstructure was necessary after 3 years from the prosthetic loading.

CONCLUSIONS

The present study suggests that the growth of the mandible near implant sites continues even after their positioning. Implants can be successfully placed and provide support for prosthetic rehabilitation in preteens patients with HED.

Prevalence of Dental Anomalies Among Orthodontic Patients: A Retrospective Study in Saudi Arabia

BACKGROUND

Odontogenic anomalies encompass deviations in dental morphology, orientation, or spatial positioning within the mandibular structures. This study probed the frequency of such dental malformations among orthodontic patients receiving treatment in Riyadh City, Saudi Arabia. Furthermore, the study sought to discern variations in the manifestation of these dental anomalies related to gender and nationality.

MATERIALS AND METHODS

A retrospective analysis was conducted on 384 panoramic radiographs belonging to orthodontic patients (comprising 222 males and 162 females) who sought treatment at orthodontic clinics of a privately owned university hospital in Riyadh City between 2017 and 2019. The patient records were scrutinized for various dental abnormalities, including but not limited to dilacerated teeth, supernumerary teeth, congenital absence of teeth, impactions, hyperdontia, hypodontia, taurodontism, tooth rotation, and amelogenesis imperfecta. The Chi-square test was employed to assess the correlation between the prevalence of dental anomalies and variables such as gender and nationality. A p-value of less than 0.05 was deemed statistically significant for all tests.

RESULTS

Among the assessed sample size of orthodontic patients, dental impactions emerged as the most prevalent dental anomaly, affecting 246 patients (64.1%). This was followed by the occurrence of supernumerary teeth in 31 patients (8.1%), hyperdontia in 29 patients (7.6%), and congenital absence of teeth in 28 patients (7.3%). Other less frequently observed dental irregularities included dilacerated teeth in 23 patients (6%), amelogenesis imperfecta in 12 patients (3.1%), taurodontism in 12 patients (3.1%), and tooth rotations in five patients (1.3%). A statistically significant gender-based disparity was observed, with dental impactions being more prevalent among males (n=154; 69.4%) than females (n=92; 56.8%). Conversely, supernumerary teeth were more prevalent among females (n=24; 14.8%) than males (n=7; 3.2%). No significant variation in the prevalence of dental anomalies was discernible across different nationalities.

CONCLUSION

Impactions and the presence of supernumerary teeth were the predominant dental anomalies detected among the studied orthodontic patient population. The prevalence of dental anomalies exhibited discernible variations based on gender but not nationality. These disparities could potentially influence orthodontic outcomes, underscoring the necessity for meticulous examination and tailored orthodontic treatment planning.

The genetic and environmental contributions to variation in the permanent dental arch form: a twin study

OBJECTIVE

The objective of this study was to examine the relative contributions of genetic and environmental influences on variation in dental arch form in individuals who have largely completed their craniofacial growth.

MATERIAL AND METHODS

The subjects of this study comprised dental casts of 50 monozygotic twins and 24 dizygotic twins from the collection of records of twins housed at the Adelaide Dental School, Australia. The subjects were of Western European descent, with an average age of 20.93 ± 5.58 years. Dental casts were scanned using a 3D scanner to analyse the dental arch form. Landmark-based inter-arch and intra-arch measurements were performed. Structural equation modelling was employed to analyse the quantitative data using the normal assumptions of the twin model.

RESULTS

Genetic modelling revealed that additive genetic and unique environmental factors best explained the observed variation for all occlusal traits measured, except for mandibular intercanine width. High heritability was observed for most intra-arch occlusal variables (0.61-0.85) including the maxillary and mandibular intercanine and intermolar widths, arch depth and perimeter. In contrast, moderate heritability was found for inter-arch occlusal variables (0.52-0.59) such as overjet and overbite. Sexual dimorphism was evident, with males displaying larger posterior arch width than females (P < 0.05).

LIMITATIONS

Our sample was limited to individuals of Western European ancestry.

CONCLUSION

The predominant source of occlusal variation within this group of Australian twins of Western European descent was controlled by genetic effects, and most were highly heritable. Generally, intra-arch occlusal variables showed greater heritability compared with inter-arch occlusal variables.

The prevalence and risk factors of dental disease found in 100 miniature horses

Introduction

Dental disease is a common condition affecting horses. Its prevalence and characteristics among most of the common breeds of horses and donkeys have been investigated and described in the literature, but information about the prevalence and etiology of dental disease of miniature horses is sparse.

Methods

To determine the prevalence and characteristics of dental disease of miniature horses, we performed oral and dental radiographic examinations on 100 miniature horses. The findings of these examinations were analyzed to determine the prevalence of dental disease and its correlation to age, sex, weight, body condition score, height at the withers, head length and head width. Older horses had a higher prevalence of dental disease, diastemata and crown elongations.

Results

The most common dental diseases detected in this population were crown elongation, oral mucosal ulceration, diastemata, class 1 malocclusion and hypodontia. Horses with a high body condition score had an increased likelihood of having a class 1 malocclusion. Horses with wider heads had a higher prevalence of dental disease and class 1 malocclusions.

Conclusion

Frequent oral examinations, starting at an early age, should be prioritized as a part of miniature horse preventive health care to decrease morbidity and slow progression of dental disease.

LRP4 mutations, dental anomalies, and oral exostoses

BACKGROUND

In order to generate a normal set of teeth, fine-tuning of Wnt/β-catenin signaling is required, in which WNT ligands bind to their inhibitors or WNT inhibitors bind to their co-receptors. Lrp4 regulates the number of teeth and their morphology by modulating Wnt/β-catenin signaling as a Wnt/β-catenin activator or inhibitor, depending on its interactions with the partner proteins, such as Sostdc1 and Dkk1.

AIM

To investigate genetic etiologies of dental anomalies involving LRP4 in a Thai cohort of 250 children and adults with dental anomalies.

DESIGN

Oral and radiographic examinations and whole exome sequencing were performed for every patient.

RESULTS

Two novel (p.Leu1356Arg and p.Ala1702Gly) and three recurrent (p.Arg263His, p.Gly1314Ser, and p.Asn1385Ser) rare variants in low-density lipoprotein receptor-related protein 4 (LRP4: MIM 604270) were identified in 11 patients. Oral exostoses were observed in five patients.

CONCLUSION

Antagonism of Bmp signaling by Sostdc1 requires the presence of Lrp4. Mice lacking Lrp4 have been demonstrated to have alteration of Wnt-Bmp-Shh signaling and an abnormal number of incisors. Therefore, the LRP4 mutations found in our patients may disrupt Wnt-Bmp-Shh signaling, thereby resulting in dental anomalies and oral exostoses. Root maldevelopment in the patients suggests an important role of LRP4 in root morphogenesis.

Global Trends and Hotspots in Research on Tooth Agenesis: A 20-Year Bibliometric Analysis

Tooth agenesis, one of the most common developmental defects in humans, not only impairs oral function but can also lead to craniofacial deformities. Bibliometric analysis can reveal significant shifts in research and publishing trends within specific fields. This study aims to provide a comprehensive overview of the research hotspots in tooth agenesis and predict future trends through bibliometric analysis. We searched for English-language publications related to tooth agenesis from 2001 to 2021 on the Web of Science. The publications were limited to original and review articles, and bibliometric parameters such as publication year, country, institution, author, journal, citations, and keywords were extracted and analyzed using VOSviewer, Microsoft Excel 2010, and CiteSpace. A total of 2,287 papers were ultimately selected. The results show that the USA holds a leading position in the field of tooth agenesis research. A total of 9,803 authors participated in these studies, with Alexandre R Vieira from the USA being the most prolific and most cited author. This study indicates that multidisciplinary management has become the consensus first choice for treating dental agenesis. Gene mutations related to tooth agenesis continue to be a research hotspot attracting scholarly attention. Exploring the relationship between tooth agenesis and cancer may be a future research direction. These findings contribute to potential collaborations among experts in future research on the genetic causes of tooth agenesis and tumor development and to assist the scientific community by identifying research gaps in this field.

A Conservative Approach towards Aesthetic, Functional, and Psychological Management of Non-Syndromic Oligodontia Patient: A Case Report with 12-Year Follow-up

Dental agenesis is the most common developmental aberration in humans, and it is typically linked with a variety of other oral anomalies. Oligodontia, anodontia, and hypodontia are the words used in the literature to denote missing teeth. Although tooth agenesis is not a serious public health problem, it can cause speech, masticatory, aesthetic, and functional problems. A multidisciplinary approach is necessary to establish comprehensive treatment planning, counselling sessions, and frequent follow-ups, to obtain stable, functional, and psychological rehabilitation, which will eventually improves the patient's quality of life. In this case study, after considering the young age and growth of the patient and also his financial status, a conservative approach to rehabilitate the non-syndromic oligodontia patient with a 12-year follow-up and fabrication of maxillary overlay denture and mandibular conventional complete denture has been discussed.

Orthodontic Management of Severe Hypodontia and Impacted Maxillary Second Molars in a Patient with Sotos Syndrome

Sotos syndrome is a genetic disorder characterized by distinct craniofacial features, overgrowth in childhood, and impaired intellectual development. We herein report the successful orthodontic treatment of a 14-year-old boy with Sotos syndrome caused by a heterozygous mutation in the NSD1 gene. He showed severe hypodontia, impaction of the maxillary second molars and a skeletal Class III jaw-base relationship. Orthodontic management, including space control by protraction of the maxillary first molars and traction of the impacted molars, was performed using fixed appliances and miniscrews. As a result, acceptable occlusion was obtained without any discernible relapse 18 months postretention.

Identification of potential key variants in mandibular premolar hypodontia through whole-exome sequencing

Determining genotype-phenotype correlations in patients with hypodontia is important for understanding disease pathogenesis, although only a few studies have elucidated it. We aimed to identify genetic variants linked to non-syndromic bilateral mandibular second premolar hypodontia in a Korean population for the first time by specifying the phenotype of hypodontia. Twenty unrelated individuals with non-syndromic bilateral mandibular second premolar hypodontia were enrolled for whole-exome sequencing. Using a tooth agenesis gene set panel consisting of 112 genes based on literature, potential candidate variants were screened through variant filtering and prioritization. We identified 13 candidate variants in 12 genes, including a stop-gain variant (c.4750C>T) in LAMA3. Through the functional enrichment analysis of the prioritized genes, several terms related to tooth development were enriched in a protein-protein interaction network of candidate genes for mandibular premolar hypodontia. The hypodontia group also had approximately 2-fold as many mutated variants in all four genes related to these key terms, which are CDH1, ITGB4, LAMA3, LAMB3, as those in the 100 healthy control group individuals. The relationship between enriched terms and pathways and mandibular premolar hypodontia was also investigated. In addition, we identified some known oligodontia variants in patients with hypodontia, strengthening the possibility of synergistic effects in other genes. This genetic investigation may be a worthwhile preliminary attempt to reveal the pathogenesis of tooth agenesis and sets a background for future studies.

The quality and reliability of the Internet as a source of information for hypodontia patients

OBJECTIVES

The aim of this study was to determine the quality, reliability and usability of information on the Internet regarding hypodontia.

METHOD

A survey of patients with hypodontia revealed seven key search terms favoured by patients: Hypodontia; Congenitally missing teeth; Missing teeth; Gaps in teeth; Cure of missing teeth; Information on missing teeth; and Treatment of missing teeth. These were entered into four search engines: Google; Ask; Wikipedia; and NHS Choices. Relevant websites were assessed for their overall demographics, author type, country of origin and rank within the search engine. They were then analysed using five validated assessment tools. Intra-examiner reliability was assessed, and statistical analysis of the data was undertaken.

RESULTS

Good intra-examiner reliability was observed. A total of 48 websites were included for analysis from an initial 1718. There was no relationship between the ranking of a website on a search engine and the quality of information it contained. When medical search terminology was used, it resulted in websites of better quality than layperson search terms. Most websites were produced by general dental or specialist dental practices but the quality of these was poorer than those developed by private companies and medical organisations. The country of origin was primarily the USA and UK; however, this had no relationship to website quality. Overall, the majority of websites scored poorly for the validated tools and none scored well across multiple tools. A statistical analysis showed a positive relationship between the LIDA and DISCERN instruments but no other correlation between other validated tools was found.

CONCLUSION

The quality and reliability of information on the Internet regarding hypodontia is generally poor. There is a need for a reliable online hypodontia resource that can be recommended for patient use.

Permanent Tooth Eruption Patterns in Nigerian Local Pigs

Pigs are diphyodonts with heterodont dentition and have been used in studies involving teeth and jawbone regeneration, and dental implants. Patterns of tooth eruption are used to age animals and determine the effects of environmental and genetic influences on occurrence of variations. As with other species, variations exist in the tooth eruption pattern in pigs. The aim of this study was to determine the permanent teeth eruption patterns of Nigerian local pigs. Twenty-six healthy pigs were observed throughout the study period. Pigs were firmly held in dorsal or lateral recumbency and their mouths gently held open to visually examine all quadrants of the dental arches (right and left maxillary, right and left mandibular). Observations were recorded from 16 weeks of age, until the last permanent tooth erupted. Results obtained from the study showed that males had lower mean values for eruption time (54%) of examined teeth in comparison to females. The mean values of eruption time for the maxillary third incisor, the mandibular and maxillary canines, and the mandibular fourth premolar teeth were statistically significant in the males (P = .0017, P = .0088, P = .0002 and P = .0244, respectively). Sixty-nine percent of the adult pigs did not have eruption of the mandibular first premolar, while polydontia was observed in the maxillary and mandibular incisors. These results show that intra-breed and inter-breed variations exist in the dental eruption pattern in pigs. The data obtained from this study can be used for comparative dental studies and can aid further research on the developmental anatomy of Nigerian local pigs.

Availability of Third Molars as Donor Teeth for Autotransplantation to Replace Congenitally Absent Second Premolars in Children and Young Adults

The aim of the study was to assess the presence and distribution of third molars (M3) regarding their autotransplantation in patients with congenital absence of second premolars (PM2). Additionally, M3 development in relation to patients' age and gender was investigated. Panoramic radiographs of non-syndromic patients with at least one congenitally absent PM2 were used to assess the localization and number of missing PM2 and the presence or absence of M3 (minimum age 10 years). The alternate logistic regression model was applied to analyze associations between the presence of PM2 and M3. A total of 131 patients with PM2 agenesis were identified (82 females, 49 males). At least one M3 was present in 75.6% and all M3 were present in 42.7% of patients. A statistically significant association between the number of PM2 and M3 agenesis was found; the effects of age and gender were not significant. More than half of M3 in patients between 14-17 years old had completed ¼ of their root development. The congenital absence of maxillary PM2 was associated with the absence of maxillary PM2, M3, and no correlation was found in the mandible. In patients with PM2 agenesis, at least one M3 is often present and can be considered as a donor tooth for autotransplantation.

Chitosan Hydrogel-Delivered ABE8e Corrects PAX9 Mutant in Dental Pulp Stem Cells

Hypodontia (dental agenesis) is a genetic disorder, and it has been identified that the mutation C175T in PAX9 could lead to hypodontia. Cas9 nickase (nCas9)-mediated homology-directed repair (HDR) and base editing were used for the correction of this mutated point. This study aimed to investigate the effect of HDR and the base editor ABE8e in editing PAX9 mutant. It was found that the chitosan hydrogel was efficient in delivering naked DNA into dental pulp stem cells (DPSCs). To explore the influence of the C175T mutation in PAX9 on the proliferation of DPSCs, hydrogel was employed to deliver PAX9 mutant vector into DPSCs, finding that the PAX9-containing C175T mutation failed to promote the proliferation of DPSCs. Firstly, DPSCs stably carrying PAX9 mutant were constructed. Either an HDR or ABE8e system was delivered into the above-mentioned stable DPSCs, and then the correction efficiency using Sanger sequencing and Western blotting was determined. Meanwhile, the ABE8e presented significantly higher efficiency in correcting C175T compared with HDR. Furthermore, the corrected PAX9 presented enhanced viability and differentiation capacity for osteogenic and neurogenic lineages; the corrected PAX9 even possessed extremely enhanced transcriptional activation ability. In summary, this study has powerful implications for studies into base editors, chitosan hydrogel, and DPSCs in treating hypodontia.

Oral health-related Quality of Life in patients with Oligodontia: a FACE-Q assessment

OBJECTIVES

The present study aimed to investigate the impact of oligodontia on appearance and on the functional and psychosocial aspects of oral health-related quality of life (OHrQoL) in patients aged 8-29 years.

METHODS

62 patients with oligodontia that were registered at -REDACTED- were included. A control group included 127 patients that were referred for a first orthodontic consultation. Participants completed the FACE-Q Dental questionnaire. Regression analyses were performed to explore relationships between OHrQoL and patient-identified gender, age, the number of congenitally missing teeth, active orthodontic treatment, and previous orthodontic treatment.

RESULTS

The only clear significant difference between the oligodontia and control groups was that patients with oligodontia scored lower in the domain, 'eating and drinking' (p<0.001). It was found that, in oligodontia the greater the number of agenetic teeth, the more difficulties eating and drinking. In fact, the Rasch score was reduced by 1.00 (95% CI: 0.23-1.77; p=0.012) for each extra agenetic tooth. Older children scored significantly lower than younger ones on five out of nine scales: appearance of the face, smile, and jaws; social function; and psychological function. Females scored significantly lower than males on four scales: appearance of the face, appearance distress, social function, and psychological function.

CONCLUSION

These findings suggested that, when treating patients with oligodontia, the number of agenetic teeth, age, and gender should be taken into account. These factors could have negative effects on their self-assessment of appearance, their facial function, and their quality of life.

CLINICAL SIGNIFICANCE

The increased difficulty with eating and drinking associated with more agenetic teeth highlighted the importance of functional (re)habilitation.

Unexplained Fever in Infancy: Report of a Rare Case of Hypohidrotic Ectodermal Dysplasia in an Infant

Hypohidrotic ectodermal dysplasia (HED) is a genetic condition that affects structures derived from the ectoderm during embryonic development. These structures include the outermost layer of the primary germ layers, which give rise to various body parts such as the ears, eyes, lips, and mucous membranes of the nose and mouth. Due to the impact on these structures, hypohidrotic ectodermal dysplasia can manifest differently in various age groups. However, the three primary characteristics typically associated with this condition are hypotrichosis, hypohidrosis, and hypodontia or anodontia. Here, we present a case of a male infant, aged 2 months, who was brought to our attention due to symptoms of unexplained fever and irritability. The child's family history was noteworthy, as an older sibling had distinctive features of ectodermal dysplasia. This information led us to consider the possibility of this diagnosis. This case report aims to highlight the distinctive features of such cases that facilitate the identification of this condition and its related complications. By sharing this case, we intend to raise awareness and encourage timely detection, diagnosis, and proper treatment of patients with this condition.

Non-syndromic Oligodontia in Primary Dentition: A Report of a Rare Case

The congenital absence of teeth is the most common dental anomaly affecting 2.2% to 10% of the population. It could be present in the form of anodontia, hypodontia, or oligodontia, excluding wisdom teeth. Oligodontia is most commonly associated with several syndromes like ectodermal dysplasia, Down syndrome, and Van der Woude syndrome that involve the mutation of the MSX-1 and PAX-1 genes. Few cases have been reported in the literature on how oligodontia affects primary dentition. In this case report, a total of 17 primary teeth were missing. This case report investigates whether the features of non-syndromic oligodontia are present in the primary dentition in a two-year-old boy.

An International Investigation of Molar Incisor Hypomineralisation (iMIH) and Its Association with Dental Anomalies: Development of a Protocol

BACKGROUND

Molar incisor hypomineralisation (MIH) is a common disorder of tooth development, which has recently been found to be associated with a higher prevalence of hypodontia. The aim of this international multicentre study is to determine the association between MIH and other developmental anomalies in different populations.

METHODS

Investigators were trained and calibrated for the assessment of MIH and dental anomalies and ethical approvals obtained in each participating country. The study aimed to recruit 584 children with MIH and 584 children without MIH. Patients aged 7-16 years who attend specialist clinics will be invited to participate. Children will undergo a clinical examination to determine the presence and severity of MIH, using an established index. The presence of any other anomalies, affecting tooth number, morphology, or position, will be documented. Panoramic radiographs will be assessed for dental anomalies and the presence of third permanent molars. Statistical analysis, using a chi squared test and regression analysis, will be performed to determine any differences in dental anomaly prevalence between the MIH and non-MIH group and to determine any association between dental anomalies and patient characteristics.

CONCLUSION

This large-scale study has the potential to improve understanding about MIH with benefits for patient management.

PAX9 mutations and genetic synergism in familial tooth agenesis

Familial tooth agenesis (FTA) is one of the most common craniofacial anomalies in humans. Loss-of-function mutations in PAX9 and WNT10A have been known to cause FTA with various expressivity. In this study, we identified five FTA kindreds with novel PAX9 disease-causing mutations: p.(Glu7Lys), p.(Val83Leu), p.(Pro118Ser), p.(Ser197Argfs*23), and c.771+4A>G. Concomitant PAX9 and WNT10A pathogenic variants found in two probands with severe phenotypes suggested an effect of mutational synergism. All overexpressed PAX9s showed proper nuclear localization, excepting the p.(Pro118Ser) mutant. Various missense mutations caused differential loss of PAX9 transcriptional ability. PAX9 overexpression in dental pulp cells upregulated LEF1 and AXIN2 expression, indicating a positive regulatory role for PAX9 in canonical Wnt signaling. Analyzing 176 cases with 63 different mutations, we observed a distinct pattern of tooth agenesis for PAX9-associated FTA: Maxillary teeth are in general more frequently affected than mandibular ones. Along with all second molars, maxillary bicuspids and first molars are mostly involved, while maxillary lateral incisors and mandibular bicuspids are relatively less affected. Genotypically, missense mutations are associated with fewer missing teeth than frameshift and nonsense variants. This study significantly expands the phenotypic and genotypic spectrums of PAX9-associated disorders and reveals a molecular mechanism of genetic synergism underlying FTA variable expressivity.

Hypohidrotic ectodermal dysplasia: a case report

Hypohidrotic ectodermal dysplasia (HED) is a rare heterogeneous genetic congenital disorder affecting at least 1 in 5000-10,000 newborns. This disorder has a wide range of clinical manifestations; it affects organs originating from the embryonic ectoderm.

Case presentation

We present a case of a 2-year-old boy diagnosed with HED, the boy was suffering from absence of sweating since birth, dry skin, recurrent episodes of hyperpyrexia, sparse and light-colored hair on the scalp, absent eyebrows, and delayed eruption of abnormally shaped teeth.

Clinical discussion

The are no diagnostic criteria guidelines for HED, we diagnosed the disorder by the clinical manifestations and the family history. The management of patients with HED is palliative.

Conclusion

This disorder needs multidisciplinary contribution to improve the general health of those patients, quality of life, and decrease morbidity and mortality.

CACNA1S mutation-associated dental anomalies: A calcium channelopathy

OBJECTIVES

To identify the molecular etiology of distinct dental anomalies found in eight Thai patients and explore the mutational effects on cellular functions.

MATERIALS AND METHODS

Clinical and radiographic examinations were performed for eight patients. Whole exome sequencing, mutant protein modelling, qPCR, western blot analysis, scratch assays, immunofluorescence, confocal analysis, in situ hybridization, and scanning electron micrography of teeth were done.

RESULTS

All patients had molars with multiple supernumerary cusps, single-cusped premolars, and a reduction in root number. Mutation analysis highlighted a heterozygous c.865A>G; p.Ile289Val mutation in CACNA1S in the patients. CACNA1S is a component of the slowly inactivating L-type voltage-dependent calcium channel. Mutant protein modeling suggested that the mutation might allow leakage of Ca²⁺ or other cations, or a tightening, to restrict calcium flow. Immunohistochemistry analysis showed expression of Cacna1s in the developing murine tooth epithelium during stages of crown and root morphogenesis. In cell culture, the mutation resulted in abnormal cell migration of transfected CHO cells compared to wildtype CACNA1S, with changes to the cytoskeleton and markers of focal adhesion.

CONCLUSIONS

The malformations observed in our patients suggest a role for calcium signaling in organization of both cusps and roots, affecting cell dynamics within the dental epithelium.

Enhanced socket preparation during autotransplantation: a new treatment protocol

OBJECTIVE

Tooth autotransplantation (AT) is a viable option for the replacement of unrestorable or missing teeth. Recently, the use of a 3D replica of a donor tooth constructed from CBCT scans was described. The model is made to assess the recipient site's size and minimize the required extraoral time of the donor tooth after extraction. The aim of the paper was to describe a new technique for AT using the 3D replica as a socket preparation tool.

CASE REPORT

A 13-year-old boy who presented with hypodontia was referred for consultation and treatment. The treatment plan included combined orthodontic treatment and AT of the mandibular left second premolar into the site of the congenitally missing maxillary right canine. A titanium 3D model of the donor tooth was printed by a direct metal laser 3D printer utilizing the model from the CBCT scan. An intrasulcular flap was elevated, and the edentulous maxillary ridge was prepared using implant trephine burs with increasing diameters. A surgical mallet was utilized to apply vertical forces to the 3D-printed model, which was inserted into the prepared socket to allow a perfect fit for the donor tooth. After atraumatic extraction of the mandibular left second premolar, the donor tooth was inserted into the ready socket and splinted. Follow-up examinations at 1, 3, and 6 months, and 1 year after surgery demonstrated a successful outcome.

CONCLUSION

The titanium replica was successfully used for precise preparation of the recipient site, minimizing the extraoral time of the procedure to 4 minutes, and thereby improving the expected outcome. (Quintessence Int 2023;54:142-148; doi: 10.3290/j.qi.b3649031).

Genetic and Morphological Variation in Hypodontia of Maxillary Lateral Incisors

(1) Background: Hypodontia has a multifactorial aetiology, in which genetic factors are a major component. Associated with this congenital absence, the formed teeth may show differences in size and shape, which may vary with the specific genetic variants and with the location of the missing teeth. The aims of the present study were to investigate a specific variant of MSX1, derive morphometric tooth measurements in a sample of patients with isolated maxillary lateral incisor agenesis and matched controls, and model the findings. (2) Methods: Genotyping of the MSX1 rs8670 genetic variant and morphometric measurements with a 2D image analysis method were performed for 26 hypodontia patients and 26 matched controls. (3) Results: The risk of upper lateral incisor agenesis was 6.9 times higher when the T allele was present. The morphometric parameters showed significant differences between hypodontia patients and controls and between the unilateral and bilateral agenesis cases. The most affected crown dimension in the hypodontia patients was the bucco-lingual dimension. In crown shape there was significant variation the Carabelli trait in upper first molars. (4) Conclusions: The MSX1 rs8670 variant was associated with variations in morphological outcomes. The new findings for compensatory interactions between the maxillary incisors indicate that epigenetic and environmental factors interact with this genetic variant. A single-level directional complex interactive network model incorporates the variations seen in this study.

WNT10A and RUNX2 mutations associated with non-syndromic tooth agenesis

The goal of this study was to examine the prevalence of WNT10A and RUNX2 mutations and assess their potential impact on the phenotype of non-syndromic tooth agenesis. The study included 30 participants with non-syndromic tooth agenesis, divided into hypodontia (n = 24) and oligodontia forms (n = 6), and 42 unaffected family members. Genomic DNA from buccal epithelial cells was used for polymerase chain reaction amplification of functionally important exons of the WNT10A and RUNX2 genes. Direct sequencing reactions were performed to confirm the presence of mutations. The trend of increasing prevalence of WNT10A mutations and a slight increase in the prevalence of RUNX2 mutations were revealed in tooth agenesis cases compared to unaffected family members. There was a higher prevalence of hypodontia than oligodontia, increased frequency of females over males with missing teeth, and a wide phenotypic variability was observed in individuals and families analyzed. The common missense mutations (p.Phe228Ile, p.Arg113Cys, p.Asp217Asn, and p.Gly165Arg) and c.114-56T>C in the WNT10A gene and in-frame-deletion/insertions (11A, 24Q, 30Q), synonymous variant c.240G>A, and 424-33dupC in the RUNX2 gene were identified. These findings highlight an important role of WNT10A and RUNX2 mutations in the genetic etiology of non-syndromic tooth agenesis.

Comparison of craniofacial morphology in individuals with and without hypodontia with a special focus on the number of congenitally missing teeth

Background

Hypodontia might negatively affect dental function and esthetics, what might affect patients' self-esteem, communication behavior, professional performance and thus quality of life. The aim of this study was to estimate the influence of number of congenital missing teeth on dentofacial features.

Methods

Lateral cephalograms of 60 individuals with hypodontia (study group) and 40 individuals without hypodontia (control group) were analyzed. Patients in the study group were divided into two subgroups according to the number of missing teeth (group A with hypodontia 1 to 4 teeth and group B with hypodontia 5 or more teeth). Cephalometric data were compared among the study and control groups and statistically analyzed.

Results

The results in the present study revealed a significantly shorter and more retrognathic maxilla, more prognathic chin position, more retruded incisors in both jaws, large interincisal angle, straighter facial convexity as well as more retruded upper and lower lips in the group B compared with the control group. In the group A only chin position was significantly more prognathic compared with the control group.

Conclusions

According to the results of present study impact of hypodontia on the craniofacial morphology and consequently on facial esthetics was found statistically significantly greater in patients with 5 or more congenitally missing teeth.

Novel Candidate Genes for Non-Syndromic Tooth Agenesis Identified Using Targeted Next-Generation Sequencing

Non-syndromic tooth agenesis (ns-TA) is one of the most common dental anomalies characterized by the congenital absence of at least one permanent tooth (excluding third molars). Regarding the essential role of genetic factors in ns-TA aetiology, the present study aimed to identify novel pathogenic variants underlying hypodontia and oligodontia. In a group of 65 ns-TA patients and 127 healthy individuals from the genetically homogenous Polish population, the coding sequences of 423 candidate genes were screened using targeted next-generation sequencing. Pathogenic and likely pathogenic variants were identified in 37 (56.92%) patients, including eight nucleotide alternations of genes not previously implicated in ns-TA (CHD7, CREBBP, EVC, LEF1, ROR2, TBX22 and TP63). However, since only single variants were detected, future research is required to confirm and fully understand their role in the aetiology of ns-TA. Additionally, our results support the importance of already known ns-TA candidate genes (AXIN2, EDA, EDAR, IRF6, LAMA3, LRP6, MSX1, PAX9 and WNT10A) and provide additional evidence that ns-TA might be an oligogenic condition involving the cumulative effect of rare variants in two or more distinct genes.

Evaluating the Prevalence and Distribution of Dental Anomalies in the Permanent Dentition of Patients Seeking Dental Care

BACKGROUND

 Disturbances seen during tooth formation result in developmental dental anomalies presenting in the oral cavity. These anomalies manifest as discrepancies in the number, color, size, and shape of the teeth. These dental anomalies can either be acquired, congenital, or developmental. Their early detection and management are necessary as they affect aesthetics and occlusion. The study had the aim of gauging the prevalence of developmental anomalies in the permanent dentition of Indian subjects.

METHODS

A total of 1192 participants recruited from the institute for study purposes, comprising males and females, were examined clinically and radiographically, and their dental casts were also evaluated. These subjects were assessed for anomalies in position, structure, number, and/or shape. Anomalies in the position include transmigration, transportation, and/or ectopic position; anomalies in the structure, including dentinogenesis imperfecta or amelogenesis imperfecta; anomalies in number, including hyperdontia or hypodontia; and anomalies in shape, including peg laterals, taurodontism, fusion, dens evaginatus, talon cusp, and/or microdontia.

RESULTS

A statistically significant difference was seen in unilateral microdontia and dentinogenesis imperfecta between males and females, with attained p-values of 0.003 and 0.06, respectively. The results of the present study showed that 9.89% (n = 118) study subjects, whereas 1% (n = 12) study subjects had two dental anomalies in their permanent dentitions, with no subject presenting more than two dental anomalies, showing that various dental anomalies have a low prevalence in the Indian population.

CONCLUSION

The present study has led to the conclusion that the prevalence of dental anomalies is low in Indian subjects. However, these anomalies should be detected and treated early to prevent them from causing further complications.

Tooth Agenesis Patterns in Orofacial Clefting Using Tooth Agenesis Code: A Meta-Analysis

Individuals with orofacial clefting (OFC) have a higher prevalence of tooth agenesis (TA) overall. Neither the precise etiology of TA, nor whether TA occurs in patterns that differ by gender or cleft type is yet known. This meta-analysis aims to identify the spectrum of tooth agenesis patterns in subjects with non-syndromic OFC and controls using the Tooth Agenesis Code (TAC) program. An indexed search of databases (PubMed, EMBASE, and CINAHL) along with cross-referencing and hand searches were completed from May to June 2019 and re-run in February 2022. Additionally, unpublished TAC data from 914 individuals with OFC and 932 controls were included. TAC pattern frequencies per study were analyzed using a random effects meta-analysis model. A thorough review of 45 records retrieved resulted in 4 articles meeting eligibility criteria, comprising 2182 subjects with OFC and 3171 controls. No TA (0.0.0.0) was seen in 51% of OFC cases and 97% of controls. TAC patterns 0.2.0.0, 2.0.0.0, and 2.2.0.0 indicating uni- or bi-lateral missing upper laterals, and 16.0.0.0 indicating missing upper right second premolar, were more common in subjects with OFC. Subjects with OFC have unique TA patterns and defining these patterns will help increase our understanding of the complex etiology underlying TA.

MSX1 Drives Tooth Morphogenesis Through Controlling Wnt Signaling Activity

Tooth agenesis is a common structural birth defect in humans that results from failure of morphogenesis during early tooth development. The homeobox transcription factor Msx1 and the canonical Wnt signaling pathway are essential for "bud to cap" morphogenesis and are causal factors for tooth agenesis. Our recent study suggested that Msx1 regulates Wnt signaling during early tooth development by suppressing the expression of Dkk2 and Sfrp2 in the tooth bud mesenchyme, and it demonstrated partial rescue of Msx1-deficient molar teeth by a combination of DKK inhibition and genetic inactivation of SFRPs. In this study, we found that Sostdc1/Wise, another secreted Wnt antagonist, is involved in regulating the odontogenic pathway downstream of Msx1. Whereas Sostdc1 expression in the developing tooth germ was not increased in Msx1-/- embryos, genetic inactivation of Sostdc1 rescued maxillary molar, but not mandibular molar, morphogenesis in Msx1-/- mice with full penetrance. Since the Msx1-/-;Sostdc1-/- embryos exhibited ectopic Dkk2 expression in the developing dental mesenchyme, similar to Msx1-/- embryos, we generated and analyzed tooth development in Msx1-/-;Dkk2-/- double and Msx1-/-;Dkk2-/-;Sostdc1-/- triple mutant mice. The Msx1-/-;Dkk2-/- double mutants showed rescued maxillary molar morphogenesis at high penetrance, with a small percentage also exhibiting mandibular molars that transitioned to the cap stage. Furthermore, tooth development was rescued in the maxillary and mandibular molars, with full penetrance, in the Msx1-/-;Dkk2-/-;Sostdc1-/- mice. Together, these data reveal 1) that a key role of Msx1 in driving tooth development through the bud-to-cap transition is to control the expression of Dkk2 and 2) that modulation of Wnt signaling activity by Dkk2 and Sostdc1 plays a crucial role in the Msx1-dependent odontogenic pathway during early tooth morphogenesis.

Distribution of congenitally missing teeth and treatment options for the lower second premolars in patients referred to special care

OBJECTIVE

The aim was to evaluate the distribution of congenitally missing teeth and the treatment provided for congenitally missing lower second premolars in an eleven-year cohort of patients referred to a publicly funded source of specialist care.

MATERIAL AND METHODS

This was a retrospective, register-based cohort study. Search for patients referred to a publicly funded source of specialist care based on ICD10 diagnosis code K00.00 (partial anodontia) and treatment codes EBA00, EBA05, EBA10, EBA12, EBB10 and EBB20 during the period 1.1.2009-27.10.2019 yielded 232 patients (151 females, 81 males), of whom 218, born in 1941-2009, were eligible. Data collected from medical files were presented in the form of descriptive statistics and analysed using Fisher's exact test.

RESULTS

The 218 subjects possessed 876 congenitally missing teeth (males 307, females 569) (third molars excluded). The most common missing teeth were upper second premolars and lateral incisors, and lower second premolars and central incisors. No difference in laterality was found. Statistically significant associations were found between the choice of treatment and both the patient's age at referral and the patient's year of birth. Most common treatment for adult patients (age 18-56 years) was placement of an implant (67%), while autotransplantation (11%) was the preferred option for children at the mixed dentition stage (age 9-15 years).

CONCLUSIONS

The congenitally missing teeth most commonly involved in referrals of patients to publicly funded specialist care were lower second premolars. The most frequent treatment was insertion of an implant for adults and autotransplantation at the mixed dentition stage.

Mutations in LRP5 and BMP4 are associated with mesiodens, tooth agenesis, root malformation, and oral exostoses

WNT/β-catenin and BMP signaling pathways play important roles in the process of tooth development. Dysregulation of WNT/β-catenin and BMP signaling is implicated in a number of human malformations, including dental anomalies. Whole exome and Sanger sequencing identified seven patients with LRP5 mutations (p.Asn1121Asp, p.Asp856Asn, p.Val1433Met, and p.Val1245Met) and six patients with BMP4 mutations (p.Asn150Lys, p.Gly168Arg, p.Arg269Gln, and p.Ala42Glu). All patients were affected with isolated dental anomalies (dental anomalies with no other structural defects), including mesiodens, tooth agenesis, unseparated roots, narrow roots, shortened and tapered roots, and taurodontism. Five and a patients with LRP5 and BMP4 mutations had oral exostoses, respectively. Protein models of LRP5 mutations indicate the possible functional effects of the mutations. Here we report for the first time that mutations in LRP5 are associated with dental anomalies. LRP5 appears to be the first gene related to pathogenesis of mesiodens. We also show for the first time that in addition to tooth agenesis, mutations in BMP4 are also implicated in root maldevelopment and torus mandibularis. Sharing the phenotypes of the patients with LRP5 and BMP4 mutations, which include root maldevelopment, tooth agenesis, and torus mandibularis, implicates cross-talks between WNT/β-catenin and BMP signaling pathways, especially during root development.

Patterns of molar agenesis associated with p.P20L and p.R77Q variants in PAX9

Nonsyndromic tooth agenesis is associated with variants in several genes. There are numerous genotype-phenotype publications involving many patients and kindreds. Here, we identified six Thai individuals in two families with nonsyndromic tooth agenesis, performed exome sequencing, and conducted functional experiments. Family 1 had four affected members carrying the heterozygous PAX9 variant, c.59C>T (p.Pro20Leu). The p.Pro20Leu was previously reported in two families having four and three affected members. These seven cases and Proband-1 had agenesis of at least three third molars. Family 2 comprised two affected members with agenesis of all 12 molars. Both individuals were heterozygous for c.230G>A (p.Arg77Gln) in PAX9, which has not been reported previously. This variant is predicted to be damaging, evolutionarily conserved, and resides in the PAX9 linking peptide. The BMP4 RNA levels in Proband-1's leukocytes were not significantly different from those in the controls, whereas BMP4 levels observed in Proband-2 were significantly increased. Moreover, the p.Arg77Gln variant demonstrated nuclear localization similar to the wild-type but resulted in significantly impaired transactivation of BMP4, a PAX9 downstream gene. In conclusion, we demonstrate that the PAX9 p.Pro20Leu is highly associated with absent third molars, while the novel PAX9 p.Arg77Gln impairs BMP4 transactivation and is associated with total molar agenesis.

A Rare Case of Hypohidrotic Ectodermal Dysplasia in a Seven-Year-Old Child

Ectodermal dysplasias (EDs) encompass a large group of inherited disorders that affects two or more ectodermally derived structures. Hair, sweat glands, teeth, and nails are the most common ectodermal derivates affected. Other ectodermal structures that may be affected are ears, eyes, lips, and mucous membranes of the mouth or nose. During embryonic development, the ectoderm forms the outermost layer of the primary germ layers that give rise to the several structures that are commonly affected in ED. Therefore, ED manifests differently among patients, depending on the abnormality's combination and severity. Out of 150 distinctive syndromes, the most common syndromes within this group are hypohidrotic (defective sweat glands) and hidrotic (normal sweat glands). In addition, different types of inheritance patterns are found in ED; X-linked inheritance is by far the most common mode of inheritance. We present here the clinical case of hypohidrotic (anhidrotic) ED in a seven-year-old boy.

A novel removable appliance for canine retraction: a case report

This case report outlines the use of a modified Leighton's retractor as a method for canine retraction in a patient with severe hypodontia, a history of aggressive periodontitis with tooth loss and idiopathic root resorption affecting multiple teeth. Treatment involved an upper removable appliance in combination with a lower sectional fixed appliance with the aim of improving aesthetics and function for the patient, whilst balancing the need to minimise treatment duration and modify treatment mechanics to reduce the orthodontic risks.

A rare occurrence of nonsyndromic focal microdontia of primary teeth with hypodontia of permanent teeth in a pediatric patient

Dental anomalies in human dentition consist of a considerable variation in size, number, position, shape and structure of the tooth. Microdontia is defined as a condition in which teeth are abnormally smaller in size. Hypodontia is defined as developmental absence of 1–5 teeth excluding third molars. Simultaneous occurrence of multiple dental anomalies is most commonly seen in patients with some abnormality or syndrome; it can also occur in nonsyndromic patients. This case report describes about an unusual simultaneous occurrence of dental anomalies such as localized microdontia of primary teeth and hypodontia in a nonsyndromic 10-year-old male patient. Simultaneous occurrence of multiple dental anomalies in a nonsyndromic patient is rare. As the treatment of such cases involves multiple phases, identification and proper timely management is important to help the patient lead a better quality life.

The prevalence and management of patients with hypodontia: A cross -sectional study

BACKGROUND

Hypodontia is one of the most common anomalies in dentistry. Hypodontia has a negative impact on oral health-related quality of life with patients best seen in a multidisciplinary clinic to improve treatment outcomes.

AIM

To investigate the prevalence of hypodontia and its association with other dental anomalies, as well as malocclusion, and to investigate the treatment planned for patients attending the clinic and whether the type of missing teeth affected the proposed treatment.

MATERIALS AND METHODS

Analysis of consecutive patients attending the hypodontia clinic at a dental hospital between February and November 2020. A total of 100 patients who met the inclusion criteria were identified. Data collected included the following: age/sex; number and type of missing teeth; pre-treatment occlusion; presence of other dental anomalies; and planned treatment.

RESULTS

A total of 100 patients (55% female; age range = 7-41 years; mean age = 18 years) were included. Of the cohort, 47% had a class I skeletal relationship and participants were significantly less likely to have a class III skeletal or incisor relationship; 45% had another dental anomaly with the most common being microdontia. Space opening was the preferred treatment option for those managed by orthodontic treatment with resin-bonded bridges most likely to be used for restoration of spaces, 86%.

CONCLUSION

Lower second premolars were the most commonly missing teeth. Participants were significantly less likely to have a class III incisor or skeletal relationship than class I or II. Space opening was the favoured approach for orthodontic treatment, particularly for maxillary lateral incisors.

Rehabilitation of ectodermal dysplasia patient with a telescopic denture in the maxilla and mandibular implant assisted overdenture: A case report

Hypohidrotic ectodermal dysplasia is a heritable disease, characterized by hypodontia, hypotrichosis, and anhidrosis. This clinical report demonstrates prosthetic rehabilitation of a patient complaining of impaired mastication and the odd appearance of her jaws. Maxillary telescopic overdenture and implant-supported mandibular prostheses were fabricated to improve mastication, speech, and esthetics of the patient.

Evaluation of the effects of hypodontia on the morphology of craniofacial structures

OBJECTIVE

The study aimed to investigate the effects of hypodontia on the sagittal and vertical dimensions of the jaws, dentition and the related soft tissue.

MATERIALS AND METHODS

The hypodontia group included 111 patients whose growth was completed with one or more congenitally missing teeth (CMT). Sixty additional patients with skeletal and dental class I relationship, without CMT, and who completed growth, were included as the control group. The hypodontia group was divided into three subgroups according to the intermaxillary (maxillary or mandibular) location, intramaxillary (anterior or posterior) location and the severity of hypodontia (mild: 1-2 CMT or moderate: 3-6 CMT). Twenty-three measurements were performed on lateral cephalograms of the patients. The one-way and Kruskal-Wallis Analysis of Variance tests were used for the statistical analysis. The false discovery-rate analysis was applied for the multiple comparison adjustment.

RESULTS

No significant difference was found in the skeletal measurements between all hypodontia subgroups and the control (P > .05). Upper incisors were found to be retroclined in the anterior hypodontia group. The upper lip was found to be protruded in the mandibulary hypodontia group compared to the control (P < .05).

CONCLUSION

The mild-to-moderate hypodontia did not produce a significant skeletal effect. However, hypodontia can affect the incisors, especially when CMT is in the anterior region. Besides, the effects of severe hypodontia could not be evaluated due to the insufficient number of oligodontia patients.

Synergistic Mutations of LRP6 and WNT10A in Familial Tooth Agenesis

Familial tooth agenesis (FTA), distinguished by developmental failure of selected teeth, is one of the most prevalent craniofacial anomalies in humans. Mutations in genes involved in WNT/β-catenin signaling, including AXIN2 WNT10A, WNT10B, LRP6, and KREMEN1, are known to cause FTA. However, mutational interactions among these genes have not been fully explored. In this study, we characterized four FTA kindreds with LRP6 pathogenic mutations: p.(Gln1252*), p.(Met168Arg), p.(Ala754Pro), and p.(Asn1075Ser). The three missense mutations were predicted to cause structural destabilization of the LRP6 protein. Two probands carrying both an LRP6 mutant allele and a WNT10A variant exhibited more severe phenotypes, suggesting mutational synergism or digenic inheritance. Biallelic LRP6 mutations in a patient with many missing teeth further supported the dose-dependence of LRP6-associated FTA. Analysis of 21 FTA cases with 15 different LRP6 loss-of-function mutations revealed high heterogeneity of disease severity and a distinctive pattern of missing teeth, with maxillary canines being frequently affected. We hypothesized that various combinations of sequence variants in WNT-related genes can modulate WNT signaling activities during tooth development and cause a wide spectrum of tooth agenesis severity, which highlights the importance of exome/genome analysis for the genetic diagnosis of FTA in this era of precision medicine.

Sella Turcica Abnormalities, Dental Age and Dental Abnormalities in Polish Children

The frequency of some sella turcica abnormalities on cephalometric radiographs is age related. Chronological age might not overlap with growth; however, no studies could be found on the association between sellar morphology and dental age. Although an association exists between sella turcica bridging and dental abnormalities, no studies have been found correlating sellar abnormalities other than bridging with dental abnormalities. The aim of this study was to find any correlations between sella turcica abnormalities and dental age or dental abnormalities. Methods: Lateral cephalograms and panoramic radiographs of 206 children aged 6–15 years were analyzed for sela turcica abnormalities, Demirijan dental age, and dental abnormalities. Results: The prevalence of dental abnormalities in patients with sela turcica abnormalities was 16.98%, while in those with normal sella, it was 3%. The differences between dental and chronological age were higher in patients with sella turcica abnormalities (p = 0.002). Dental abnormalities were more prevalent (p = 0.001) in patients with sellar abnormalities other than sellar bridging than in those with sellar bridging or normal sella. Conclusions: Sella turcica abnormalities are correlated with delayed dental age. Dental abnormalities are more frequent in patients with sellar abnormalities. Dental abnormalities are less frequent in subjects with sellar bridges compared to those with other sellar abnormalities.

Gene Mutations of the Three Ectodysplasin Pathway Key Players (EDA, EDAR, and EDARADD) Account for More than 60% of Egyptian Ectodermal Dysplasia: A Report of Seven Novel Mutations

Ectodermal dysplasia (ED) is a diverse group of genetic disorders caused by congenital defects of two or more ectodermal-derived body structures, namely, hair, teeth, nails, and some glands, e.g., sweat glands. Molecular pathogenesis of ED involves mutations of genes encoding key proteins of major developmental pathways, including ectodysplasin (EDA) and wingless-type (WNT) pathways. The most common ED phenotype is hypohidrotic/anhidrotic ectodermal dysplasia (HED) featuring hypotrichosis, hypohidrosis/anhidrosis, and hypodontia. Molecular diagnosis is fundamental for disease management and emerging treatments. We used targeted next generation sequencing to study EDA, EDAR, EDARADD, and WNT10A genes in 45 Egyptian ED patients with or without hypohidrosis. We present genotype and phenotype data of 28 molecularly-characterized patients demonstrating genetic heterogeneity, variable expressivity, and intrafamilial phenotypic variability. Thirteen mutations were reported, including four novel EDA mutations, two novel EDARADD, and one novel EDAR mutations. Identified mutations congregated in exons encoding key functional domains. EDA is the most common gene contributing to 85% of the identified Egyptian ED genetic spectrum, followed by EDARADD (10%) and EDAR (5%). Our cohort represents the first and largest cohort from North Africa where more than 60% of ED patients were identified emphasizing the need for exome sequencing to explore unidentified cases.

From Child to Adulthood, a Multidisciplinary Approach of Multiple Microdontia Associated with Hypodontia: Case Report Relating a 15 Year-Long Management and Follow-Up

Oral rehabilitation of patients presenting multiple microdontia is a real therapeutic challenge. These alterations in size, often associated with other dental anomalies, have aesthetic and functional repercussions for patients and can lead to significant psycho-social consequences. We report here the case of an 11-year-old patient with bilateral sectorial microdontia and agenesis of teeth numbers 13 and 23. She also presented staturo-ponderal delay and a history of acute coronary syndrome with a lower coronary occlusion of unknown aetiology. At first, additive coronoplasties and an orthodontically retained interim prosthesis answered the aesthetic and functional need during childhood and adolescence. Once she reached adulthood, a multidisciplinary meeting was conducted and a treatment plan was established. The decision was made to rehabilitate the upper arch with a permanent bridge and the lower arch with indirect adhesive restorations. This solution solved the problem of the bilateral lateral infraocclusions and tooth agenesis, restoring both aesthetics and function. This paper presents 15 years of management and treatment of a patient presenting multiple microdontia associated with hypodontia. Both the multidisciplinary approach and coordination between the different medical team members was essential to maintain the existing dentition while preparing, planning, and carrying out a personalized treatment plan once maxillofacial growth was complete.

Gastrointestinal symptoms in patients with isolated oligodontia and a Wnt gene mutation

OBJECTIVE

Since Wnt signaling plays an important role in both tooth agenesis and altered intestine homeostasis, the aim was to compare gastrointestinal symptoms in patients with isolated oligodontia caused by a Wnt pathway gene mutation and controls.

METHODS

A case-control study was designed to compare self-reported gastrointestinal symptoms among patients with isolated oligodontia, caused by a Wnt signaling gene mutation, and fully dentate controls. The Gastrointestinal Symptom Rating Scale (GSRS) was used to assess gastrointestinal symptoms. Prevalence and severity of gastrointestinal symptoms among patients and age- and gender-matched controls were evaluated.

RESULTS

Twenty patients with isolated oligodontia and a pathogenic variant in the wnt pathway genes WNT10A, LRP6, or PAX9 participated. The prevalence of gastrointestinal symptoms was higher in the oligodontia patients compared to their controls (Χ² (1) = 87.33, p = .008). Mean GSRS total scores (p = .011) and domain scores for "abdominal pain" (p = .022), "reflux" (p = .003) and constipation (p = .030) were higher for these oligodontia patients compared to their controls.

CONCLUSION

Gastrointestinal symptoms are more prevalent and more severe in patients with isolated oligodontia and a deficiency in a Wnt pathway-related gene, when compared to controls without tooth agenesis.

A novel report of dental development pattern in a 3-year-old girl with three congenitally missing primary canines: A review of the literature and a case study

Dentists may encounter patients with numerical dental anomalies in clinical practice and understanding of these conditions would allow early detection as well as intervention. The absence of one or more teeth congenitally is referred as hypodontia. This dental anomaly is rarely reported in primary dentition and the most commonly affected teeth in the primary dentition are mandibular lateral incisors and primary canines are remarkably very rare and this entity has not been often reported. This case study was aimed to report a 3-year-old Indian girl with the absence of three canines primary dentition and also evaluate the overall dental development pattern of developing permanent teeth. Furthermore, a new finding for pediatric dentists that the development of permanent canines in case of missing primary canines.

How Does Hypodontia Compare in Nonsyndromic Pierre Robin Sequence Versus Isolated Cleft Palate and Isolated Cleft Lip?

OBJECTIVE

To assess the prevalence and patterns of hypodontia in nonsyndromic Pierre Robin sequence (PRS) and compare it with hypodontia in nonsyndromic isolated cleft palates and isolated cleft lips.

DESIGN

Retrospective cohort study.

SETTING

Alder Hey Children's Hospital, United Kingdom.

PATIENTS

Patients with nonsyndromic PRS (group 1), isolated cleft palate (group 2), and isolated cleft lip (group 3).

MAIN OUTCOME MEASURES

Hypodontia in the permanent dentition assessed from orthopantomographs.

RESULTS

A total of 154 patients were included. Group 1 had the highest incidence of hypodontia with 47% having at least one tooth congenitally absent. Groups 2 and 3 had reduced rates of hypodontia with 27% and 19% of the groups missing teeth, respectively; 93% of cases of hypodontia in group 1 involved the absence of at least one second premolar. Of these patients, there was found to be bilateral agenesis of second premolars in 50% of cases.

CONCLUSIONS

Patients with PRS and cleft palates are more likely to have hypodontia than those with isolated cleft palates or unilateral cleft lips. Patients with PRS have more severe hypodontia than those with isolated cleft palates or unilateral cleft lips. Bilateral agenesis of lower second premolars is a commonly seen pattern among patients with PRS. In this large UK study, a similar prevalence and pattern of hypodontia to other nonsyndromic PRS populations worldwide has been demonstrated.

Ectodermal Dysplasia-Syndactyly Syndrome with Toe-Only Minimal Syndactyly Due to a Novel Mutation in NECTIN4: A Case Report and Literature Review

Ectodermal dysplasia-syndactyly syndrome 1 (EDSS1) is characterized by cutaneous syndactyly of the toes and fingers and abnormalities of the hair and teeth, variably associated with nail dystrophy and palmoplantar keratoderma (PPK). EDSS1 is caused by biallelic mutations in the NECTIN4 gene, encoding the adherens junction component nectin-4. Nine EDSS1 cases have been described to date. We report a 5.5-year-old female child affected with EDSS1 due to the novel homozygous frameshift mutation c.1150delC (p.Gln384ArgfsTer7) in the NECTIN4 gene. The patient presents brittle scalp hair, sparse eyebrows and eyelashes, widely spaced conical teeth and dental agenesis, as well as toenail dystrophy and mild PPK. She has minimal proximal syndactyly limited to toes 2-3, which makes the phenotype of our patient peculiar as the overt involvement of both fingers and toes is typical of EDSS1. All previously described mutations are located in the nectin-4 extracellular portion, whereas p.Gln384ArgfsTer7 occurs within the cytoplasmic domain of the protein. This mutation is predicted to affect the interaction with afadin, suggesting that impaired afadin activation is sufficient to determine EDSS1. Our case, which represents the first report of a NECTIN4 mutation with toe-only minimal syndactyly, expands the phenotypic and molecular spectrum of EDSS1.