Heredity, Genetics and Orthodontics - How Much Has This Research Really Helped?

A longitudinal study of the probability of developing malocclusion in children using a Bayesian analysis

INTRODUCTION

This study evaluated the probability of developing malocclusions in mixed dentition.

METHODS

A longitudinal study was conducted with 598 children (aged 5 years) in deciduous dentition. The children were followed for 3 years until mixed dentition (aged 8 years). Overjet, overbite, and transversal relations were evaluated. Bayesian models were used to analyze the data and estimate the parameters.

RESULTS

The parameter θ was used for the distributions, indicating the probability of presenting a given condition with a credibility index (ICr) of 95%. After 3 years of follow-up, 121 children were reevaluated. The results showed that children have a high probability of malocclusion in mixed dentition. There was a higher probability of developing an increased overjet in the mixed dentition of 20.5% (ICr 95%, 13.6-28.4) to 48.3% (ICr 95%, 39.1-57.7) and a higher probability of having a normal overbite in the deciduous dentition and a lower probability in the mixed dentition (ICr 95%, 9.2-21.3).

CONCLUSIONS

Considering the probabilistic model of Bayesian analysis, children with normal overjet in the deciduous dentition may show an increased overjet in the mixed dentition. Concerning overbite, children may present an anterior open bite during the transition between deciduous and mixed dentition, as well as self-correction of deep overbite in mixed dentition. Furthermore, they may present a posterior crossbite during the mixed dentition when there is a normal transverse relationship in the deciduous dentition.

Primary Failure Eruption: Genetic Investigation, Diagnosis and Treatment: A Systematic Review

AIM

The aim of this systematic review is to explore the pathology, diagnosis, treatment, and genetic basis of Primary Failure of Eruption (PFE) in the field of pediatric dentistry and orthodontics.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for this review. The databases PubMed, Science Direct, Scopus, and Web of Science were searched from 1 July 2013 to 1 July 2023, using keywords "primary failure of tooth eruption" OR "primary failure of eruption" OR "tooth eruption failure" OR "PFE" AND "orthodontics". The study selection process involved screening articles based on the inclusion and exclusion criteria.

RESULTS

A total of 1151 results were obtained from the database search, with 14 papers meeting the inclusion criteria. The review covers various aspects of PFE, including its clinical features, diagnosis, treatment options, and genetic associations with mutations in the PTH1R gene. Differentiation between PFE and Mechanical Failure of Eruption (MFE) is crucial for accurate treatment planning. Orthodontic and surgical interventions, along with multidisciplinary approaches, have been employed to manage PFE cases. Genetic testing for PTH1R mutations plays a significant role in confirming the diagnosis and guiding treatment decisions, although some cases may not be linked to this mutation.

CONCLUSIONS

This systematic review provides valuable insights into the diagnosis, treatment, and genetic basis of PFE. Early diagnosis and personalized treatment planning are crucial for successful management. Genetic testing for PTH1R mutations aids in accurate diagnosis and may influence treatment decisions. However, further research is needed to explore the complex genetic basis of PFE fully and improve treatment outcomes for affected individuals.

Gender and age effects on dental and palatal arch dimensions among full siblings

PURPOSE

This study was conducted to investigate the dental and palatal arch dimensions of male and female siblings in relation to gender and age, using three-dimensional (3D) digital casts.

METHODS

This study involved 54 subjects (27 pairs) of male-female siblings aged 15 to 45 years. Dental casts were digitized and analyzed for tooth size (TS), arch width (AW), arch length (AL), arch length discrepancy (ALD), and palatal arch dimensions (PAD). The data obtained were subjected to t-tests, and the palatal curvature (PC) was modeled using a fourth-order polynomial.

RESULTS

Significant differences (P < 0.05) between the sexes were found in the mesiodistal TS, particularly in all canines, as well as 16, 36, 46, and 41. Maxillary AW and AL were also significantly (P < 0.05) influenced by sexes. Most arch parameters were more prominent in male siblings, and the effect of age on PC differed between the sexes. In addition, the PC of adolescent females was mostly superimposed on adult females relative to males.

CONCLUSION

Among siblings, males were found to have significantly larger dental arch dimensions than females. Furthermore, PC showed some differences between the sexes in both the frontal and sagittal planes.

Genetic Polymorphisms of Estrogen Receptors α and β are Associated with Craniofacial Measurements in Patients With Dentofacial Deformity

Dentofacial deformities are characterized by abnormalities in craniofacial development that affects the individual's skeletal and occlusion, often causing functional and esthetic problems. In literature, there is an involvement of polymorphisms in estrogen receptor 1 (ESR1) and estrogen receptor 2 (ESR2) genes in craniofacial measurements. The aim of this study was to evaluate a possible association between polymorphisms in ESR1 (rs2234693 and rs9340799) and ESR2 (rs1256049 and rs4986938) genes with cephalometric measurements in individuals with dentofacial deformities. This cross-sectional study was performed with 158 individuals in the preoperative period of orthognathic surgery. The cephalometric measurements obtained through lateral cephalogram using Dolphin Imaging software. For genetic analysis, the DNA extracted from epithelial cells of the oral mucosa and were genotyped using the real-time polymerase chain reaction. The data found submitted to statistical analysis, through the Kolmogorov-Smirnov, Mann-Whitney, and Kruskal-Wallis tests, using the IBM SPSS software version 24.0. Considered a significance level of 0.05. We found association between polymorphisms and cephalometric measurements just in the female sex. The polymorphisms ESR1/rs9340799 ( P= 0.003), ESR1/rs2234693 ( P= 0.026), and ESR2/rs1256049 ( P= 0.046) were associated with the upper gonial angle (Ar-Go-N). The polymorphism ESR2/rs1256049 was also associated with the facial axis-rickets (NBa-PtGn) ( P= 0.004), anterior cranial base (SN) ( P= 0.036), and Y-axis (SGn-SN) ( P= 0.031).

Primary failure of eruption: occlusal and dentoalveolar characteristics in mixed and permanent dentition. A study with cone beam computed tomography

Background

The main objective of this study was to describe the dentoalveolar and occlusal characteristics of subjects with primary failure of eruption (PFE) in cone beam computed tomography (CBCT) and compare them with a control group without the anomaly.

Material and Methods

This retrospective and comparative study evaluated CBCT images of 80 permanent molars divided into 2 groups of 40 molars each, which had or did not have PFE characteristics. Using CBCT a calibrated orthodontist performed 23 measurements related to the distances of the cusps to the occlusal, palatal and mandibular planes and measured the buccal-palatal and mesiodistal widths of the molar crowns and their root lengths. Independent Student’s t or Mann-Whitney U tests were used to compare occlusal and dentoalevolar characteristics between groups according to the normality of the data. P<0.05.

Results

Molars affected by PFE were smaller in coronal dimensions in the PFE compared to the non-PFE group (Buccal-palatal crown width 11.60±0.95mm vs. 12.21±1.09 mm; p<0.001; and mesiodistal crown width 10.81± 1.07 mm vs. 11.84±1.32mm, respectively; p<0.001). The distal and mesial root lengths were approximately 2 mm smaller in the PFE group (p<0 .001). The three-dimensional bony position was more convergent with respect to the palatal plane, i.e., the crown was more inclined palatally and distally in the PFE compared to the non-PFE group.

Conclusions

Patients with molars affected by PFE present smaller bucco-palatal, mesio-distal coronal widths and mesial and distal root lengths than those without PFE and in these teeth the crowns are more inclined palatally and distally in upper molars. These specific characteristics may be pathognomonic of PFE and should be considered by clinicians when evaluating or treating patients with this condition.

Key words:Occlusal characteristics, primary failure of eruption, cone-beam CT.

Adverse pregnancy outcomes and occlusal traits in the primary dentition: A prospective cohort (BRISA)

OBJECTIVES

This study aimed to analyse the relationship between adverse pregnancy outcomes (APO) and occlusal traits in the primary dentition, checking for different mediation paths.

SETTING AND SAMPLE POPULATION

Children evaluated at birth (T1), between 12 and 24 months (T2), and between 24 and 36 months (T3) were included. Two hundred and seventeen children who participated in T1 and T2 were randomly selected to perform the occlusion examination.

MATERIALS AND METHODS

This is a prospective cohort study (BRISA). The theoretical model was tested by structural equation modelling (SEM), estimating standardized coefficients (Coeff.) (α = 0.05). The primary exposure was APO-a latent variable manifested from three health problems at birth: low birthweight (LBW), pre-term birth (PTB) and intrauterine growth restriction (IUGR), evaluated in T1. The outcomes were four different occlusal traits assessed in T3: overjet, anterior and posterior crossbite, and crowding. Each outcome's direct and indirect effects were tested, mediated by growth, breathing, breastfeeding, and pacifier use.

RESULTS

There was no direct association between APO and any of the outcomes: overjet (Coeff. = -0.163, P = .241), anterior crossbite (Coeff. = -0.696, P = .065), posterior crossbite (Coeff. = -0.087, P = .589) and crowding (Coeff. = 0.400, P = .423). The indirect (total and specifics) effects tested also showed no association (P > .05). However, APO was associated with lower child growth in all models; breastfeeding was associated with higher child growth in all models, and pacifier use was associated with overjet (Coeff. = 0.184, P < .001) and posterior crossbite (Coeff. = 0.373, P = .011).

CONCLUSION

APO was not a risk factor for overjet, crossbite and crowding in an early stage of the primary dentition by direct and indirect pathways. However, growth has been lower in children with APO and higher in children breastfed. Also, the harmful effects of using a pacifier in dental occlusion are highlighted.

[Health relevance of malocclusions and their treatment]

Zahn- und Kieferfehlstellungen gehören zu den häufigsten Mundgesundheitsbeeinträchtigungen beim Menschen. Der vorliegende Beitrag gibt eine Übersicht zu deren Ursachen, Häufigkeit und Folgen. Er zeigt die präventiven und kurativen Möglichkeiten kieferorthopädischer Behandlungen auf und gibt Informationen zu deren rechtlichen Rahmenbedingungen in Deutschland. Inanspruchnahme und Qualität der kieferorthopädischen Versorgung werden im internationalen Vergleich dargestellt.

Bei den Ursachen für Zahn- und Kieferfehlstellungen spielen genetische, epigenetische, funktionelle und umweltbedingte Faktoren eine Rolle, die individuell meist nicht eindeutig feststellbar sind. Bisher zeigen nur kleinere Querschnittsstudien, dass bis zu 80 % der Kinder in Deutschland betroffen sind. Essen, Trinken, Kauen, Sprechen und Atmen können beeinträchtigt sein, die Neigung zu Parodontalerkrankungen sowie Überlastungsschäden von Kiefergelenk und Kaumuskulatur sind erhöht. Bei einer Proklination der oberen Schneidezähne steigt die Gefahr von Frontzahntraumata. Fehlstellungen können zudem negative psychosoziale Folgen oder Einschränkungen der Lebensqualität zur Folge haben. Kieferorthopädische Behandlungen leisten in Kooperation mit anderen (zahn-)medizinischen Fachdisziplinen einen wichtigen präventiven bzw. kurativen Beitrag zur Verbesserung der Mundgesundheit, der Allgemeingesundheit und der Lebensqualität.

Die Kieferorthopädie bietet ein erhebliches Potenzial für die Stärkung der zahnärztlichen Prävention im Gesundheitswesen, zumal die gesetzliche Krankenversicherung (GKV) eine breitflächige Versorgung der Bevölkerung mit kieferorthopädischen Leistungen auf international anerkanntem, hohem Niveau ermöglicht. Um die Prävention weiter zu verbessern, wird die Einführung eines kieferorthopädischen Screenings im 7.–8. Lebensjahr als systematische Vorsorge empfohlen.

Genetics of Dentofacial and Orthodontic Abnormalities

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

[Primary failure of eruption: a French prospective survey among the orthodontists from the Grand Est and Bourgogne-Franche-Comté regions]

INTRODUCTION

 Primary failure of eruption (PFE) can be defined as the partial or complete failure of eruption of at least one posterior tooth, without any mechanical obstacle; isolated and syndromic forms exist. PFE results from an abnormal dental eruption process that can affect temporary teeth and / or permanent teeth. Molars are the main affected teeth, inducing posterior infraclusions. Orthodontists are the specialists most often concerned by this rare pathology. Unsuccessful orthodontic-surgical traction therapies are commonly reported.

MATERIALS AND METHODS

 The aim of our study using a prospective survey was to evaluate the level of knowledge reported by the orthodontists and the therapeutic difficulties they reported. An anonymous questionnaire was submitted to practitioners practicing in north-eastern France (Grand Est and Bourgogne-Franche-Comté regions).

RESULTS

 The participation rate was 33.5%. In France, until 2015, specialization in orthodontics was obtained thanks to a local qualification, the Certificat d'Etudes Cliniques Spéciales - Mention Orthodontie (CECSMO), which has now been replaced by specialization following a national ranking competition. Most respondents obtained their qualification between 1980 and 2009 (80%), via the CECSMO (87%). Eighty-six per cent were aware of PFE but only 20% of them knew that PTHR1 (Parathyroid Hormone Receptor 1) gene could be involved in this pathology. The wide range of proposed therapies and the variable satisfaction rates highlight the difficulties encountered by practitioners.

DISCUSSION

 Phenotypic variability complicates the diagnosis and makes any therapeutic systematization uncertain.

CONCLUSION

 New clinical research projects, particularly in the field of molecular diagnosis, may improve understanding of genotype-phenotype correlations, and may potentially pilot therapeutic management.