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

Dental anomalies in craniofacial microsomia and condylo-mandibular dysplasia: A retrospective study of 103 patients

INTRODUCTION

Craniofacial microsomia (CFM) and camel-hump condylo-mandibular dysplasia (CMD) are developmental disorders affecting the mandible that share common clinical features. This study aimed to investigate and compare the dental anomalies (DA) between the two entities for differential diagnosis and to propose appropriate treatment.

METHODS

This retrospective cross-sectional study was based on panoramic radiographs of patients diagnosed with CFM or CMD. DA were evaluated using the classification reported by Bilge. Delayed tooth eruption on the affected side was noted based on a comparison with the contralateral side. Nolla's stages of tooth calcification were used to assess dental development.

RESULTS

A total of 103 patients were included, 80 subjects (77.7 %) in CFM group and 23 patients (22.3 %) in CMD group. The prevalence of DA among CFM and CMD-affected patients were 80.0 % and 95.7 %, respectively. Tooth ectopia, tooth impaction, dental development delay, and delayed tooth eruption on the affected side exhibited a significant association with the two craniofacial malformations. The overall affected teeth (molars, premolars, canines) differed between the two craniofacial malformations. Dental abnormalities such as oligodontia, hyperdontia, dentin dysplasia, and anomalies of shape were seen only in subjects affected by CFM.

CONCLUSION

DA were widely observed in patients with CFM and CMD. The global distribution of affected teeth differed between the two conditions and some DA were detected only in CFM patients. When clinical diagnosis remains uncertain, some specific radiological characteristics of DA can be used to differentiate CFM from CMD.

Prevalence and characteristics of and risk factors for impacted teeth with ankylosis and replacement resorption - a retrospective, 3D-radiographic assessment

BACKGROUND

Large variation in the prevalence of ankylosis and replacement resorption (ARR) is reported in the literature and most studies have relatively small patient numbers. The present retrospective study aimed to provide an overview on prevalence, location of, and associated risk factors with ARR based on a large sample of computed tomography (CT) / cone beam computed tomography (CBCT) scans of impacted teeth. The results should allow clinicians to better estimate the risk of ARR at impacted teeth.

METHODS

The CT/CBCT scans of 5764 patients of a single center in Central Europe were screened with predefined eligibility criteria. The following parameters were recorded for the finally included population: gender, age, tooth type/position, number of impacted teeth per patient, and presence/absence of ARR. For teeth with ARR the tooth location in reference to the dental arch, tooth angulation, and part of the tooth affected by ARR were additionally registered.

RESULTS

Altogether, 4142 patients with 7170 impacted teeth were included. ARR was diagnosed at 187 impacted teeth (2.6%) of 157 patients (3.7%); 58% of these patients were female and the number of teeth with ARR per patient ranged from 1 to 10. Depending on the tooth type the prevalence ranged from 0 (upper first premolars, lower central and lateral incisors) to 41.2% (upper first molars). ARR was detected at the crown (57.2%), root (32.1%), or at both (10.7%). After correcting for confounders, the odds for ARR significantly increased with higher age; further, incisors and first/second molars had the highest odds for ARR, while wisdom teeth had the lowest. More specifically, for 20-year-old patients the risk for ARR at impacted incisors and first/second molars ranged from 7.7 to 10.8%, but it approximately tripled to 27.3-35.5% for 40-year-old patients. In addition, female patients had significantly less often ARR at the root, while with increasing age the root was significantly more often affected by ARR than the crown.

CONCLUSION

ARR at impacted teeth is indeed a rare event, i.e., only 2.6% of 7170 impacted teeth were ankylosed with signs of replacement resorption. On the patient level, higher age significantly increased the odds for ARR and on the tooth level, incisors and first/second molars had the highest odds for ARR, while wisdom teeth had the lowest.

Association of parent-reported timing of first tooth emergence and ECC: a secondary analysis of a case-control study

PURPOSE

Tooth eruption is a dynamic process. Appearance of any part of the cusp through gingiva may be a clinical marker of eruption. Early childhood caries (ECC) is a public health problem globally. This study aimed to assess the relationship between parent-reported timing of first tooth emergence and ECC in toddlers.

METHODS

This study is a secondary data analysis of 627 toddlers involved in a case-control study on sleep-time feeding practises in children. The children were categorised into four groups based on the parent-reported timing of first primary tooth emergence (G1-when the first primary tooth emerged before 6 months of age, G2-between 7 and 9 months; G3-10 to 12 months and G4-when the first primary tooth emerged after 12 months of age). Univariate binary logistic regression analysis was performed to evaluate the association between timing of first tooth emergence and ECC.

RESULTS

The mean age of the children was 24.4 ± 7.3 months (cases, that is children with ECC-25.4 ± 6.9 months, controls, that is children without ECC-23.6 ± 7.5 months). Of 60 children, whose first tooth erupted before 6 months of age, 35 (12%) were cases compared to 25(8%) controls. Amongst the cases, boys had more caries than girls (p < 0.05). Of the anterior teeth, 22% of the emerged teeth were decayed in the first group, followed by 19%, 16% and 10% in the second, third and fourth groups, respectively (p < 0.05). Analysis of the posterior teeth showed a lower percentage of decayed teeth with delayed emergence of the first primary tooth (p < 0.05). Children whose teeth emerged before 6 months of age had an odds ratio of 3.5 (95% CI 1.49, 8.42) (p = 0.004).

CONCLUSION

This study concluded that the early emergence of the first primary tooth, as reported by the parent, was associated with an increased risk of developing ECC.

Metabolic Bone Diseases Affecting Tooth Eruption: A Narrative Review

Tooth eruption is an essential process for the development of the oral and maxillofacial system. Several inherited and acquired diseases might affect this tightly regulated process, resulting in premature, delayed, or even failed tooth eruption. The purpose of this article is to review the literature and the clinical parameters of metabolic bone diseases that affect tooth eruption. It examines the physiological aspects of tooth eruption and the pathophysiological changes induced by metabolic bone diseases, including changes in bone metabolism, density, and structure. The search strategy for this review included an electronic search in PubMed, Google Scholar, Medline, Scopus, and the Cochrane Library using the following keywords: "metabolic bone diseases", "tooth eruption", "delayed tooth eruption", and each reported disease in combination with "tooth eruption disorders", covering publications up to March 2024 and limited to English-language sources. Understanding the influence of metabolic bone diseases on tooth eruption is crucial for managing both dental and skeletal manifestations associated with these disorders. This review suggests that a multidisciplinary approach to treatment may significantly improve oral outcomes for patients suffering from such conditions. Clinicians should be aware of the specific dental abnormalities that may arise and consider comprehensive evaluations and individualized treatment plans. These findings underscore the need for further research into targeted therapies that address these abnormalities.

Prevalence and Distribution of Dental Anomalies in Schoolchildren in Kuwait

OBJECTIVE

Dental anomalies (DA) can affect paediatric patients' aesthetics, function, and psychological well-being. There is a lack of data about the prevalence of DA in children in Kuwait. This study aimed to investigate the prevalence and distribution of DA amongst schoolchildren aged 8 to 12 years.

METHODS

A retrospective study was conducted using panoramic digital radiographs of children who attended a single dental center. All radiographs were evaluated by 2 calibrated and trained examiners.

RESULTS

DA were present in 110 (20.1%) out of the 546 panoramic radiographs examined: 53.6% in females and 46.4% in males. The mean age of children with DA (9.83 ± 1.29) was similar to that of children with no anomalies (9.96 ± 1.46). The most prevalent anomaly was dental agenesis (9.3%), followed by taurodontism (6.6%) and ectopic eruption (EE, 2%). DA were more common in the maxilla (58.2%) compared to the mandible (41.8%, P = .042). Congenitally missing teeth were significantly more frequent in the mandible (56.9%) than in the maxilla (43.1%, P = .003). EE was significantly more common in the maxilla (90.9%) than in the mandible (9.1%, P = .024). Microdontia and root dilacerations were only present in males, whilst supernumerary teeth, transposition, and impacted teeth were noted in females only.

CONCLUSIONS

The prevalence of DA amongst schoolchildren in Kuwait was considered to be relatively high. Certain DA were associated with gender. The significant prevalence of DA highlights the need for early diagnosis using panoramic radiographs, particularly during the ages of 9 and 10, in order to ensure effective patient management.

Local factors relating to mandibular canine impaction: A retrospective study

INTRODUCTION

This study aimed to investigate the characteristics of impacted and transmigrated mandibular canines and the association existing between them and some local factors, such as degrees of axial inclination of mandibular incisors, skeletal Class, and mandibular symphysis width.

METHODS

A retrospective observational study was performed on the medical records and radiographic examination (panoramic radiographs and lateral cephalograms) of 102 orthodontic patients divided into a study group, with at least 1 impacted mandibular canine (51 subjects) and a control group, without mandibular impaction (51 subjects). A chi-square test, t test, and analysis of variance test analysis were used to analyze the data.

RESULTS

Unilateral and buccal impaction and the presence of the deciduous canine were the more prevalent characteristics of impacted canines, whereas 39.2% presented transmigration. Furthermore, the persistence of the deciduous canine on the impaction side (P <0.0001) and the mesial axial inclination of the impacted canine (P <0.0001) were found to be statistically significant characteristics. A statistically significant association was found between the impaction of the mandibular canine and mandibular incisor to the mandibular plane angle (IMPA) (IMPA, 95.8°; P = 0.009). An additional statistically significant association was found with transmigrated canines (IMPA, 96.8°; P = 0.024).

CONCLUSIONS

The mesialization of the canine cusp and the persistence of the mandibular deciduous canine are characteristics frequently found in the impaction of the mandibular canine. An accentuated vestibular inclination of the mandibular incisors is significantly associated with mandibular canine impaction.

Survival of retained permanent canines after autotransplantation: A retrospective cohort study

INTRODUCTION

After third molars, canines are the teeth most commonly affected by displacement and impaction. Although orthodontic surgical treatment represents the standard method for realignment of canines, autotransplantation (autoTX) functions as the second-line therapy if orthodontic alignment does not succeed in treating impaction and severe displacement. This retrospective cohort study aimed to identify clinical predictors for postoperative survival and endodontic treatment needs after autoTX of severely displaced and impacted canines.

METHODS

The study cohort comprised patients who received canine autoTX in a single surgical center between 2006 and 2018. Canines with severe displacement and retention were surgically treated using a standardized protocol. Statistical analysis of survival probability was performed with the Kaplan-Meier method, and bivariate data were analyzed using logistic regression and the Pearson chi-square test. Nonparametric continuous variables were analyzed using the Mann-Whitney U test.

RESULTS

Data from 319 patients with 378 canine grafts were available for analysis after a mean follow-up of 54.7 ± 36.5 months on the patient level (range, 0.3-181.8 months). With 25 lost autotransplants, the cumulative survival rate was 93.4%. Patient age at surgery, the state of the apical foramen, endodontic treatment need, and persistence of deciduous teeth at the implantation site had a significant negative impact on autotransplant survival (P <0.05). Endodontic treatment need was significantly related to the patient's age at surgery, the state of the apical foramen, and preoperative orthodontic traction (P <0.05). Thus, these independent variables were identified as clinical predictors for the survival of both the autotransplant and the dental pulp. Gender, ischemia time, postoperative ankylosis, or site of autoTX did not influence any of the outcome variables.

CONCLUSIONS

The high survival rates of autotransplanted permanent canines make this treatment a promising option, especially in patients with severe tooth displacement, in which orthodontic treatment alone cannot provide predictable alignment, irrespective of the patient's age. Interpreting age and preoperative orthodontic traction as delaying the onset of autoTX and state of apex, time-dependent aspects seem to be of great importance for postoperative complications leading to endodontic treatment or graft loss. Therefore, early implementation of autoTX as a treatment modality for impacted, severely displaced, and vain exposed canines in daily surgical practice should be encouraged.

Dental abnormalities in rare genetic bone diseases: Literature review

Currently, over 500 rare genetic bone disorders are identified. These diseases are often accompanied by dental abnormalities, which are sometimes the first clue for an early diagnosis. However, not many dentists are sufficiently familiar with phenotypic abnormalities and treatment approaches when they encounter patients with rare diseases. Such patients often need dental treatment but have difficulties in finding a dentist who can treat them appropriately. Herein we focus on major dental phenotypes and summarize their potential causes and mechanisms, if known. We discuss representative diseases, dental treatments, and their effect on the oral health of patients and on oral health-related quality of life. This review can serve as a starting point for dentists to contribute to early diagnosis and further investigate the best treatment options for patients with rare disorders, with the goal of optimizing treatment outcomes.

TMEM119 (c.G143A, p.S48L) Mutation Is Involved in Primary Failure of Eruption by Attenuating Glycolysis-Mediated Osteogenesis

Primary failure of eruption (PFE) is a rare oral disease with an incidence rate of 0.06%. It is characterized by abnormal eruption mechanisms that disrupt tooth eruption. The underlying pathogenic genetic variant and mechanism of PFE remain largely unknown. The purpose of this study was to explore the role of a novel transmembrane protein 119 (TMEM119) mutation in two PFE patients in a Chinese family. Information collection was performed on the family with a diagnosis of PFE, and blood samples from patients and healthy family members were extracted. Whole-exome sequencing was performed. Bioinformatics analysis revealed that a heterozygous variant in the TMEM119 gene (c.G143A, p.S48L) was a disease-associated mutation in this family. Recombinant pcDNA3.1 plasmid-containing wild-type and mutant TMEM119 expression cassettes were successfully constructed and transfected into MC3T3-E1 cells, respectively. The results of in vitro analysis suggested that the subcellular distribution of the TMEM119 protein was transferred from the cell cytoplasm to the nucleus, and the ability of cells to proliferate and migrate as well as glycolytic and mineralized capacities were reduced after mutation. Furthermore, rescue assays showed that activating transcription factor 4 (ATF4) overexpression rescued the attenuated glycolysis and mineralization ability of cells. Results of in vivo analysis demonstrated that TMEM119 was mainly expressed in the alveolar bone around the mouse molar germs, and the expression level increased with tooth eruption, demonstrated using immunohistochemistry and immunofluorescence. Collectively, the novel TMEM119 mutation is potentially pathogenic in the PFE family by affecting the glucose metabolism and mineralized function of osteoblasts, including interaction with ATF4. Our findings broaden the gene mutation spectrum of PFE and further elucidate the pathogenic mechanism of PFE.

Forced eruption in impacted teeth: analysis of failed cases and outcome of re-operation

BACKGROUND

Forced eruption of an impacted tooth usually requires surgical and orthodontic interventions to successfully bring the tooth into the dental arch. The clinical time required for a forced eruption is difficult to predict before treatment begins and success rates are affected by several factors before and after an eruption. This study was conducted to identify factors that affect the success of forced eruption, the duration of orthodontic treatment of impacted teeth, and the reasons for re-operation and forced eruption failure in a various teeth and cases.

METHODS

In this retrospective study, the records regarding the forced eruption of 468 teeth in 371 patients from June 2006 to May 2020 at the Advanced General Dentistry Department of Yonsei University Dental Hospital were initially examined. The records of 214 teeth in 178 patients who completed orthodontic treatment were included in the analysis. Data on patient demographics, tooth characteristics, orthodontic treatment duration, re-operations, and failures were collected from electronic medical records.

RESULTS

There was a significant difference in age between the success and failure forced eruption. Factors significantly affecting treatment duration were apex formation, position, rotation, and re-operation. Re-operation had a 96% success rate. The average orthodontic treatment duration was 29.99 ± 16.93 months, but the average orthodontic treatment duration for teeth that undergone re-operation was 20.36 ± 11.05 months, which was approximately 9 months shorter. Additionally, there was an interaction effect between rotation and re-operation on the duration of orthodontic treatment. The causes for failure of forced eruption in 6 cases were ankyloses (3 cases), incomplete alignment with the normal dental arch (2 cases), and a significant deviation in the impacted tooth's location (1 case).

CONCLUSIONS

To increase the success rate of forced eruption, age should be considered as a priority, and in order to predict the treatment period, the apex formation status, position in the arch, and rotation should be considered in addition to age. When determining re-operation, considering factors such as ankylosis, root curvature, and apex formation can help in the success of orthodontic treatment.

Mini-Implant Insertion Using a Guide Manufactured with Computer-Aided Design and Computer-Aided Manufacturing in an Adolescent Patient Suffering from Tooth Eruption Disturbance

Due to dental diseases, anatomical restrictions, and mixed dentition, the reduction in the number of teeth and the displacement of tooth germs pose challenges in orthodontic treatment, limiting anchorage options. The presented case demonstrates an advanced treatment solution using digital CAD/CAM-technologies and medical imaging for the creation of a mini-implant template. A 12-year-old male patient experiencing delayed tooth eruption, multiple impacted germs, and maxillary constriction underwent intraoral scanning and CBCT. Utilizing coDiagnostiXTM Version 10.2 software, the acquired data were merged to determine the mini-implant placement and to design the template. The template was then manufactured through stereolithography using surgical-guide material. Mini-implants were inserted using the produced appliance, enabling safe insertion by avoiding vital structures. Surgically exposed displaced teeth were aligned using a Hyrax screw appliance anchored on the mini-implants for rapid palatal expansion (RPE) and subsequently used as fixed orthodontics to align impacted teeth. The screw was activated daily for 10 weeks, resulting in a 7 mm posterior and 5 mm anterior maxillary transversal increase. Skeletal anchorage facilitated simultaneous RPE and tooth alignment, ensuring accuracy, patient safety, and appliance stability. The presented case shows a scenario in which computer-aided navigation for mini-implant positioning can enhance precision and versatility in challenging anatomical cases.

Appropriate timing of treatment contributes to better root development of impacted anterior teeth in children

INTRODUCTION

This study investigated the effects of different timings of orthodontic treatment on the root development of impacted anterior teeth in children.

METHODS

The cone-beam computed tomography (CBCT) data of 45 children with impacted anterior teeth were divided into unformed root (UR) group or basically formed root (BFR) group to evaluate root length (RL) and root growth length (RGL) of impacted teeth and contralateral nonimpacted teeth pretreatment and posttreatment. In addition, 22 patients with impacted dilaceration were selected to assess the effects of the crown-root angle and root development stage on RL and RGL. The Student t test, Wilcoxon test, analysis of variance, and multiple linear regression analysis were used for statistical evaluations.

RESULTS

The RL of treated impacted teeth pretreatment and posttreatment was significantly shorter than contralateral nonimpacted teeth values (P <0.05). Posttreatment, the RL and RGL of impacted teeth of the UR group were significantly greater than those of the BFR group (P <0.05). The RGL of the dilacerated root in the UR group was considerably higher than in the BFR group (P <0.05). The larger crown-root angle group had a longer posttreatment RL (P <0.05). Multiple linear regression analysis revealed that the Nolla stage of impacted teeth and RL of contralateral teeth pretreatment significantly influenced the RL of impacted teeth posttreatment.

CONCLUSIONS

Prompt orthodontic treatment is necessary for children with impacted anterior teeth to release the impacted state and achieve better root development. The root length of a dilacerated tooth continued to develop under treatment, but the crown-root angle partly constrained it.

Delayed eruption of permanent maxillary first molars among Saudi children: A cross-sectional study

Aim

This retrospective cross-sectional study aimed to determine the prevalence of delayed development and eruption of permanent maxillary first molars (U6) and associated dental anomalies in a sample of Saudi children.

Material and methods

In total, 10,232 panoramic radiographs from 9,672 patients were screened for delayed U6 eruption. Radiographs showing delayed U6 eruption were further examined for associated dental anomalies. The dental age of participants was estimated using The London Atlas of Human Tooth Development and Eruption.

Result

Twenty cases of delayed U6 eruption were found, with a prevalence of 0.2%. Of these patients, 3 and 17 were males and females, respectively; 9 and 11 cases were unilateral and bilateral, respectively. Congenital absence of the adjacent permanent second molar was observed in 8 cases, and the congenital absence of permanent teeth, except the adjacent second permanent molar and third molar, was observed in 6 cases. Peg-shaped lateral incisors were observed in 6 females. No significant associations were observed between delayed U6 eruption and dental anomalies. Overall, the average delayed U6 eruption was 2.3 years for males and 2.8 years for females.

Conclusion

Among a sample of Saudi children, the prevalence of delayed U6 eruption was 1 in 483 (0.2%) and five times higher in females. No significant associations were found between delayed U6 eruption and dental anomalies; however, congenital absence of the adjacent permanent second molar was observed in 40% of cases.

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.

Dental Maturation in Two Groups of Children Born in 1969-1973 and 2005-2010

This study compared differences in dental maturation and dental age in Scandinavian children born in 1969-1973 and 2005-2010. The study was based on 130 ethnic Scandinavian children, who were divided in two groups corresponding to the time periods and matched on age and sex. Each group consisted of 65 children (30 girls, 35 boys, mean age 9.29 years and 9.30 years, respectively). Dental maturation was analysed by orthopantomographs, in accordance with Demirjian and Haavikko. Dental age was analysed by orthopantomographs in accordance with Demirjian. Boys and girls were analysed separately by linear regression analysis adjusted for age. For the children born in 2005-2010, teeth matured significantly earlier (Demirjian: 0.21 maturities, CI 95% 0.11-0.31, p < 0.000. Haavikko: maxilla: 0.39 maturities, CI 95% 0.21-0.56, p < 0.000. Mandible: 0.42 maturities, CI 95% 0.17-0.67, p = 0.001) and the dental age was significantly higher (Demirjian: 6.04 months, CI 95% 0.23-0.77, p < 0.000) in comparison with the children born in 1969-1973. In conclusion, the teeth of Scandinavian children born 2005-2010 matured significantly earlier than those of children born in 1969-1973. The results may prove valuable in forensic dentistry, pedodontics, and for the timing of pedodontic and orthodontic treatment.

Timing of Primary Tooth Eruption in Infants Observed by Their Parents

BACKGROUND

The timing of primary teeth eruption is a visible indicator of infant physical growth other than body weight or height. It also reflects neurological integrity and development as well as nutrition, socioeconomic state, or underlying diseases. Therefore, the timing of primary teeth eruption is one of the major concerns for parents in health checkups for infants and children. However, the detailed developmental timing of teeth eruption differs depending on the survey methodology, country, or generation. We hypothesized that the timing of primary teeth eruption differs between the medical checkup by dentists and the daily records by parents.

METHODS

We conducted a questionnaire survey on the date of eruption of primary teeth as an adjunct study among Miyagi Regional Center participants in the Japan Environment and Children's Study (JECS), a large-scale birth cohort study. A total of 1695 responses (3793 participants) were analyzed.

RESULTS

The median ages of eruption were 7.1 months (male) and 7.6 months (female) for mandibular primary central incisors, 8.7 months (male) and 9.2 months (female) for maxillary primary central incisors, 10.0 months (male) and 10.3 months (female) for maxillary primary lateral incisors, and 10.4 months (male) and 10.8 months (female) for mandibular primary lateral incisors, which were earlier than the reported timings based on dental check-ups. Comparing the eruption time of preterm and term infants, the eruption time was earlier in preterm infants in the corrected ages.

CONCLUSIONS

The eruption timing observed and described by the parents is earlier than that examined by dentists at regular check-ups. In addition to examining the primary teeth eruption of full-term birth children, we also examined that of preterm birth children because of the increasing number of premature births. To the best of our knowledge, this is the first report from a large cohort study to clarify the eruption time of primary teeth monitored by parents.

Trends in Primary Tooth Emergence Pattern and Associated Factors in Japanese Infants

OBJECTIVE

The purposes of this study were to analyse trends in primary tooth emergence patterns and to identify physical factors potentially associated with them.

METHODS

The participants were 27,454 infants who underwent routine 18-month-old health examinations in Ebetsu City, Japan, between 1980 and 2012. This study was conducted using data from infants' 18-month-old health examinations over a 33-year period. The mean number of emerged primary teeth was analysed by sex using a general linear model. For logistic regression analysis, the proportion of infants with 16 emerged teeth or more at 18 months old was used as a dependent variable. Examination year; birth order; birth weight; weight, height, and chest girth at 18 months old; number of fused teeth; and mother's age were used as independent variables.

RESULTS

The mean number of emerged primary teeth decreased over the 33-year period. Birth weight and weight and height at 18 months old decreased, and the proportion of low-birth-weight (<2500 g) infants increased over the 33-year period. On general linear model analysis, the yearly change in the mean number of emerged primary teeth was -0.0188 for boys and -0.0181 for girls. Birth weight and weight and height at 18 months old were significantly associated with the presence of 16 emerged primary teeth or more, according to the logistic regression analysis.

CONCLUSIONS

The results demonstrated that, over the 33-year period examined, the mean number of emerged primary teeth decreased and birth weight and weight and height at 18 months old were associated with the pattern of tooth emergence.

Fluctuating asymmetry in third molar agenesis as an aid to estimate socioeconomic status

Traditionally, dental identification techniques are used to establish identity or assist in reconstructing an individual's biological profile. However, other aspects of identity, namely socioeconomic status (SES), can be estimated through teeth. This work aims to evaluate the influence of SES on third molar agenesis in a Portuguese population. X-rays from 448 subjects (223 belonging to a high and 225 to a low socioeconomic status) were assessed and demographic data (age, sex) and dental history were registered. Frequencies and associations between the variables were analyzed using the chi-square test. For each group, differences between third molar agenesis were studied using the Wilcoxon test. The significance level was 5%. X-rays displaying at least one agenesis were more common in females (in both SES groups). Differences between socioeconomic status were found in female subjects' upper right and lower left third molars, with a higher frequency of agenesis in the lower SES group. Agenesis of lower third molars displayed fluctuant asymmetry in both groups, whereas agenesis of upper third molars was also present in the lower SES group. These results suggest that socioeconomic status can affect third molar agenesis prevalence, and fluctuant asymmetry seems more prevalent in the lower SES, as it affects all third molars.

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.

Association between dental and skeletal maturation in Scandinavian children born between 2005 and 2010

OBJECTIVE

The aim of this cross-sectional study was to analyse the association between dental and skeletal maturation in children born between 2005 and 2010.

MATERIALS AND METHODS

Dental and skeletal maturation of 117 ethnic Scandinavian children born between 2005 and 2010 (70 girls, 47 boys, mean age 11.48 years) was analysed. Dental maturation (DM) was assessed on orthopantomographs (OPs) by using Demirjian's and Haavikko's methods while skeletal maturation was assessed on hand-wrist radiographs by use of Helm's method. The correlation between skeletal and DM was analysed using Spearman's rho (Rs). Additionally, the most frequent DM stage in relation to the skeletal maturation stage was analysed by logistic regression adjusted for age and sex.

RESULTS

The correlation between dental and skeletal maturation was significant for all teeth (Rs = 0.071-0.562; p < .000-p = .035) except for the first incisor and the first molar. Logistic regression analysis showed that when the mandibular and maxillary canines are ¾ mineralized, this is significantly associated with the beginning of the adolescent period before peak height velocity (PHV) (PP2= p < .005-< .05). Likewise, when the mandibular second premolars are ¾ mineralized, this is significantly associated with the maturation stage PP2= or S (PP2= p < .05, S: p < .005-< .05), both of which are before PHV at the beginning of the adolescent period.

LIMITATIONS

Limited sample size and the X-rays were taken before orthodontic treatment, which may have introduced a selection bias.

CONCLUSIONS

When the root of the canines or second premolars is ¾ mineralized, it may indicate the beginning of the adolescent period with increased skeletal growth intensity.

Novel Genetic Determinants of Dental Maturation in Children

Dental occlusion requires harmonious development of teeth, jaws, and other elements of the craniofacial complex, which are regulated by environmental and genetic factors. We performed the first genome-wide association study (GWAS) on dental development (DD) using the Demirjian radiographic method. Radiographic assessments from participants of the Generation R Study (primary study population, N1 = 2,793; mean age of 9.8 y) were correlated with ~30 million genetic variants while adjusting for age, sex, and genomic principal components (proxy for population stratification). Variants associated with DD at genome-wide significant level (P < 5 × 10-8) mapped to 16q12.2 (IRX5) (lead variant rs3922616, B = 0.16; P = 2.2 × 10-8). We used Fisher's combined probability tests weighted by sample size to perform a meta-analysis (N = 14,805) combining radiographic DD at a mean age of 9.8 y from Generation R with data from a previous GWAS (N2 = 12,012) on number of teeth (NT) in infants used as proxy of DD at a mean age of 9.8 y (including the ALSPAC and NFBC1966). This GWAS meta-analysis revealed 3 novel loci mapping to 7p15.3 (IGF2BP3: P = 3.2 × 10-8), 14q13.3 (PAX9: P = 1.9 × 10-8), and 16q12.2 (IRX5: P = 1.2 × 10-9) and validated 8 previously reported NT loci. A polygenic allele score constructed from these 11 loci was associated with radiographic DD in an independent Generation R set of children (N = 703; B = 0.05, P = 0.004). Furthermore, profiling of the identified genes across an atlas of murine and human stem cells observed expression in the cells involved in the formation of bone and/or dental tissues (>0.3 frequency per kilobase of transcript per million mapped reads), likely reflecting functional specialization. Our findings provide biological insight into the polygenic architecture of the pediatric dental maturation process.

Use of third molar eruption based on Gambier's criteria in assessing dental age

The biological aspects of determining the dental age of subadults represent an important interdisciplinary scientific link with applications in criminal law and in forensic anthropology and dentistry. In criminal procedural law, it is necessary to determine the exact age of an undocumented person in view of the application of the provisions on juvenile offenders and minor victims. Chronological age can be estimated from the development of the third molars, as these are the only teeth that develop at the age of 18. The aim of this study was to verify the applicability of the Gambier method based on the eruption of the third permanent molars in the mandible and maxilla, to contribute to forensic age assessment. The analyzed group that met the criteria consisted of 811 orthopantomograms (OPGs) (339 females and 472 males) between the ages of 13 and 25 years. The OPGs were retrospectively analyzed according to the method of Gambier et al. (Int J Legal Med 133:625-632, 29), which refers to the eruption stages of the third molar. Differences between eruption stages of maxillary and mandibular third molars were statistically significant in both biological sexes. Intersexual differences in mean age were significant only at stage 3 for any M3 tooth and at stage 1 for mandibular M3. There were no statistically significant differences between the left and right mandibular and maxillary third molars, respectively. Differences between mandibular and maxillary M3 were significant only for stage 1 in males on the left side and for stage 2 in both sexes and sides. The method used allowed the best classification of individuals into minor and adult groups (based on phase D-90.41% of individuals, based on the third stage of the mandibular left third molar-86.29%). Based on the results obtained, we can assume that the method cannot be used alone in the initial examination of living individuals, since all four third molars must be assessed and there are no additional findings from practice.

Complete Pseudo-Anodontia in an Adult Woman with Pseudo-Hypoparathyroidism Type 1a: A New Additional Nonclassical Feature?

Pseudo-anodontia consists in the clinical, not radiographic, absence of teeth, due to failure in their eruption. It has been reported as part of an extremely rare syndrome, named GAPO syndrome. Pseudo-hypoparathyroidism type 1a (PHPT-1a) is a rare condition, characterized by resistance to the parathyroid hormone (PTH), as well as to many other hormones, and resulting in hypocalcemia, hyperphosphatemia, and elevated PTH. We report here the case of a 32-year-old woman with a long-standing history of non-treated hypocalcemia, in the context of an undiagnosed PHPT-1a. She had an intellectual disability, showed clinical features of the Albright hereditary osteodystrophy (AHO) and presented signs of multiple hormone resistances. She received treatment for seizures since the age of six. Examination of her mouth revealed a complete absence of teeth. Treatment of hypocalcemia and hormone deficiencies were started only at 29 years of age. Genetic testing demonstrated the presence of a frameshift variant in the GNAS gene in the proband as well as in her mother. A Single Nucleotide Polymorphism (SNP) array analysis failed to demonstrate pathogenic copy number variants (CNVs) but showed several regions with loss of heterozygosity (LOHs) for a final percentage of 1.75%, compatible with a fifth degree of relationship. Clinical exome sequencing (CES) ruled out any damaging variants in all the teeth agenesis-related genes. In conclusion, although we performed an extensive genetic analysis in search of possible additional gene alterations that could explain the presence of the peculiar phenotypic characteristics observed in our patient, we could not find any additional genetic defects. Our results suggest that the association of genetically confirmed PHPT-1a and complete pseudo-anodontia associated with persistent patchy alopecia areata is a new additional nonclassical feature related to the GNAS pathogenic variant.

Prevalence of Delayed Eruption of Permanent Upper Central Incisors at a Tertiary Hospital in Riyadh, Saudi Arabia

Tooth eruption is defined as the axial movement of the tooth from its site of development in the alveolar bone to its functional position in the oral cavity. A delay in eruption can directly affect the accurate diagnosis, overall treatment planning, and timing of treatment. Thus, Delayed Tooth Eruption can have a significant impact on a patient’s proper health care. This study aimed to estimate the prevalence of delayed eruptions of permanent upper central incisors in Riyadh, Saudi Arabia. A retrospective study assessed panoramic radiographs of children between the ages of 6–10 years old who attended the Dental University Hospital clinics at King Saud University in Riyadh, Saudi Arabia between 2014 and 2020. The radiographs were collected and examined to detect any delayed eruption of the permanent upper central incisors. Panoramic radiographs with delayed erupted permanent upper central incisors were identified by tooth developmental stages and eruption sequence. Of the 745 radiographs, 23 (3.09%) presented at least one delayed erupted permanent upper central incisor of which boys and girls comprised 16 (69.5%) and 7 (30.4%), respectively. Retained primary teeth was the most causative factor of delayed eruption (43.4%), followed by the early loss of primary teeth (21.7%) and insufficient arch space. The present study is the first to assess the prevalence of delayed eruption of the permanent upper central incisors on a Saudi population. Boys were found to have more prevalence of delayed eruption of the permanent upper central incisors compared to girls. Clinicians should be aware of such a condition as early diagnosis of delayed eruption is essential for providing optimal dental care.

Prevalence of Dental Anomalies in Taiwanese Children with Cleft Lip and Cleft Palate

The aim of this study was to investigate the prevalence of tooth agenesis, tooth malformation, and eruption patterns of upper canines/first premolars in Taiwanese children. A total of 132 cleft lip and cleft palate (CLCP) patients (82 boys and 50 girls) underwent alveolar bone grafting (ABG) between 2012 and 2022. The patients' dental records and X-ray images were inspected. We examined dental anomalies, including congenital missing teeth, microdontia, and transposition from the upper canines to the upper first premolars in these CLCP patients. Additionally, we investigated the mean ABG operation age (9.27 ± 0.76 years) of our patient; 40.9% of them received pre-ABG orthodontic treatment at 8.72 ± 0.70 years. Among the 132 cleft subjects, the prevalence of tooth agenesis is 73.5% (97/132). The most frequently missing teeth are the maxillary lateral incisors (right side: 46.2%; left side: 47.0%). In this study, microdontia are found in all the upper incisors, of which the highest percentage (18.9%) is observed in the upper left lateral incisors. The prevalence of upper canine and first premolar transposition is 10.6%. The pattern of tooth agenesis and microdontia of the upper lateral incisors shows a strong correlation with the cleft sites of these CLCP patients in our study. These results may support the idea that the patterns of dental anomalies in CLCP patients are region-specific.

Dental Caries and Dental Anomalies in Children Undergoing Chemotherapy for Malignant Diseases

Purpose

The study aims to evaluate the prevalence of dental caries and anomalies in pediatric patients undergoing chemotherapy or those who have completed chemotherapy.

Methods

A total of 250 pediatric patients within the age group of 6 months to 17 years, either admitted to hospitals for chemotherapy or on follow-up, were included as a part of the study. Complete oral examination inclusive of the diet history, oral hygiene methods, past dental history, the decayed, missing, and filled teeth (DMFT), def score, and any dental anomaly was diagnosed clinically and radiographically using an orthopantomogram. The samples were further categorized under type of malignancies and duration of chemotherapeutic drug usage groups (from 6 months to 10 years and more than 10 years) to establish a correlation of these variables with the prevalence of dental caries and dental anomalies.

Results

Among all patients, 108 (43.2%) had completed the treatment (chemotherapy), while 142 (56.8%) were undergoing the treatment. Forty-three (17.2%) patients showed positive findings for dental anomalies.

Conclusion

The present study confirms the strong positive correlation between long-term exposure to chemotherapeutic agents and the prevalence of dental anomalies and dental caries in children.

How to cite this article

Talekar AL, Musale PK, Kothare SS. Dental Caries and Dental Anomalies in Children Undergoing Chemotherapy for Malignant Diseases. Int J Clin Pediatr Dent 2022;15(4):428-432.

Mandibular Molar Uprighting Using Skeletal Anchorage: A Novel Approach

Background: The management of eruption anomalies affecting second molars, although quite uncommon, may represent a real challenge for the clinician. The aim of this study is to present a novel technique that combines the surgical and orthodontic approach in order to obtain the retrieval of impacted second molars through a complex distalizing movement and skeletal anchorage. Methods: Nineteen consecutive patients with impacted second molars were treated according to this technique, which involved extraction of the third molar followed by the placement of a distally positioned screw, and the subsequent use of a coil spring to connect the screw to an eyelet directly bonded on the second molar. In selected cases, it proved to be necessary to reposition the second molar through traditional orthodontics. All of the parameters were recorded: the time required for completing the treatment, the initial angle between the second molar and the adjacent tooth, and treatment related-complications. Results: Twenty impacted second molars were correctly repositioned. The mean initial angle of the second molar was 55.7° (SD 22.6°, min 13.3°, max 104.8°). The mean treatment time was 10 months. There were no major complications. Conclusions: Given that periodontal tissues were minimally affected, the temporary anchorage device was fully controlled, and there was no unwanted movement of adjacent teeth, the presented technique not only proved effective but also minimally invasive.

Evaluation of the Relationship between the BMI and the Sequence and Chronology of Eruption in Permanent Dentition in Spanish Population

The aim was to analyze the relationship between BMI (body mass index) and the sequence and chronology of the eruption of permanent teeth in a sample of Spanish children. Methods: The study design was descriptive, cross-sectional, observational, and epidemiological. Patients of pediatric age were included. Emerged teeth, and patient’s age, race, and sex were recorded. The nutritional status of the child was assessed by calculating the BMI, according to the WHO parameters. Statistical analysis was carried out with a confidence interval of 95%. A prediction model with logistic regression models was obtained. Results: A total of 725 pediatric patients between 4 and 14 years old were analyzed. BMI acts as a predictor variable for eruption symmetry, as it was most frequent in overweight children (p < 0.001). The probability of symmetry in dental eruption increases for South American children, for an extra month of age, and each meter of height. BMI had an influence in the first tooth to appear only in the fourth quadrant. BMI did not seem to influence present teeth, and the sequence of permanent dental eruption was not influenced by the BMI category. Conclusions: Age, weight, height, and BMI act as significant predictors for eruption symmetry. BMI does not produce alterations in the eruption sequence of the permanent dentition.

Teeth Eruption Disorders: A Critical Review

Dental eruption refers to the vertical displacement of a tooth from its initial non-functional towards its functional position. Tooth eruption disorders may be expressed in various clinical conditions, which may be grouped as “primary retention” and “secondary retention”. The purpose of this article is to review the literature and the clinical parameters of the various conditions related to tooth eruption disorders. Materials and Methods: The search strategy of this critical review included keywords in combination with MeSH terms in Medline, Scopus, and Cochrane Library until February 2022 and only in English. Results: “Primary Failure of Eruption” (PFE) occurs during the eruption process and includes clinical characteristics of both primary and secondary retention, which make diagnosis difficult. PFE is distinguished by Types I and II. In Type I, the defect in the eruption process occurs in all the relative teeth at the same time, whilst in Type II, the clinical expressions vary in multiple quadrants of the mouth, and the second molars erupt more. The variability of the PFE’s clinical spectrum seems to be connected to a genetic origin. The differential diagnosis among single ankylosis, secondary retention, and PFE is based on the occlusal relationship between the upper and the lower teeth distally, most commonly the first molar, which has not yet fully erupted. The treatment approach depends on many factors and combines surgical and orthodontic techniques.

Dimensional and morphologic characteristics of unilateral impacted maxillary central incisors

INTRODUCTION

This cross-sectional study aimed to investigate the crown and root characteristics of impacted central incisors compared with spontaneously erupted contralateral incisors and the influence of etiologic and local factors on their dimensions.

METHODS

Forty-five patients (22 boys, 23 girls) who underwent orthodontic treatment for unilateral impaction of maxillary central incisors were referred for cone-beam imaging. Dimensions of the impacted and contralateral incisors were assessed using Dolphin 3D software (Dolphin Imaging & Management Solutions, Chatsworth, Calif). Paired t test and linear regression were used to compare the characteristics of the impacted and contralateral teeth.

RESULTS

Contralateral and impacted central incisors showed statistically significant differences for root length (95% confidence interval [CI], 2.32-3.46; P <0.001), mesiodistal crown-root angulation (95% CI, 4.09-15.95; P = 0.001), and labiolingual crown-root angulation (95% CI, -18.69 to -4.70; P = 0.002). Etiologic factors did not alter the dimensions of incisors (95% CI, -1.17 to 0.76; P = 0.672). According to the multiple linear regression the independent variables associated with root length of contralateral and impacted incisors were sex (β = -0.904; 95% CI, -1.62 to - 0.19; P = 0.014) and the presence of impaction (β = -2.87; 95% CI, -3.67 to -2.07; P <0.001).

CONCLUSIONS

Regardless of their etiology, the impacted incisors showed roots that were 2.89 mm shorter than the contralateral incisors and had greater angulation in the mesiodistal and labiolingual directions. Girls showed a reduction of 0.904 mm (7.6%) on the lengths of roots of both impacted and contralateral central incisors. The presence of impaction led to a reduction of 25% in incisor root lengths. Approximately 30% of the impacted teeth showed crown-root angulations >20° resulting in an increased distal and labial angulation of the root apical portion.

Inborn errors of metabolism and their impact in paediatric dentistry

The management of paediatric patients with inborn errors of metabolism (IEM) presents an unparalleled challenge for paediatric dentists owing to the multiplex of interrelated dental manifestations and metabolic management necessitating modifications to dental care. Inborn errors of metabolism describe a largely heterogenous group of genetic disorders namely attributable to a single gene defect essential for a specific metabolic pathway. Approximately 400 disorders have been described with an overall incidence of 1 in 5000 live births worldwide. Clinical presentation is classically inconspicuous and insidious in the neonatal period with pathophysiology attributable to accumulation of toxic by-products which interfere with normal function, or insufficient synthesis of essential compounds. This paper aims to discuss the primary oral and maxillofacial manifestations across the scope of inborn errors of metabolism, whilst also considering how metabolic treatment has the propensity to complicate dental management.

A new mammal from the Lower Cretaceous Jehol Biota and implications for eutherian evolution

Here we report on a new Early Cretaceous eutherian represented by a partial skeleton from the Jiufotang Formation at Sihedang site, Lingyuan City, Liaoning Province that fills a crucial gap between the earliest eutherians from the Yixian Formation and later Cretaceous eutherians. The new specimen reveals, to our knowledge for the first time in eutherians, that the Meckelian cartilage was ossified but reduced in size, confirming a complete detachment of the middle ear from the lower jaw. Seven hyoid elements, including paired stylohyals, epihyals and thyrohyals and the single basihyal are preserved. For the inner ear the ossified primary lamina, base of the secondary lamina, ossified cochlear ganglion and secondary crus commune are present and the cochlear canal is coiled through 360°. In addition, plesiomorphic features of the dentition include weak conules, lack of pre- and post-cingula and less expanded protocones on the upper molars and height differential between the trigonid and talonid, a large protoconid and a small paraconid on the lower molars. The new taxon displays an alternating pattern of tooth replacement with P3 being the last upper premolar to erupt similar to the basal eutherian Juramaia. Parsimony analysis places the new taxon with Montanalestes, Sinodelphys and Ambolestes as a sister group to other eutherians. This article is part of the theme issue 'The impact of Chinese palaeontology on evolutionary research'.

Treatment of ankylosed deciduous molars with or without permanent successors in children and adolescents: a systematic review

INTRODUCTION

The aim of this systematic review was to provide guidelines for decision-making during orthodontic treatment planning of infra-occluded deciduous molars with or without their successors in children and adolescents.

EVIDENCE ACQUISITION

Computerized search was conducted on Medline via PubMed, and Cochrane Library. Articles published until 2020 in English language were analyzed following the Preferred Reporting Items for Systematic Reviews (PRISMA) Checklist. Observational and interventional longitudinal studies reporting the treatment of ankylosed deciduous molars with or without successor tooth in 3 to 15-year-old patients were included.

EVIDENCE SYNTHESIS

In case of ankylosis with presence of successor, exfoliation took place in 77% of teeth, while extraction involved 23%. Infra-occlusion happened in 53% of teeth (worsening in 52%), alveolar bone loss in 37%, mesial tipping of first permanent molar in 5%, and over-eruption of antagonist in no cases (after exfoliation and eruption of successor). In case of ankylosis without successor, exfoliation took place in 1% of teeth, progression of infra-occlusion in 42%, progression of root resorption in 58%, development of mesial tipping of first permanent molars in 25%, while no case of antagonist over-eruption was reported.

CONCLUSIONS

When the permanent tooth is present and the ankylosed tooth is slightly or moderately infra-occluded, observation is appropriate. In case of severe infra-occlusion or absence of successor, tooth extraction may be considered together with orthodontic space closure, transplantation, or prosthetic replacement. Alternatively, nonextraction and a prosthetic build-up may be considered.

Lack of association between delayed tooth emergence and single nucleotide polymorphisms in estrogen receptors

The purpose of the study was to investigate the association between single nucleotide polymorphisms (SNPs) in genes encoding estrogen receptors (ESR1 and ESR2, respectively) and delayed tooth emergence (DTE). This cross-sectional study was composed of biological unrelated children of both sexes, age ranging from 11 to 13 years old. DTE was defined when the successor primary tooth was still present in the oral cavity after its exfoliation time or the absence of the permanent tooth emergence into the oral cavity. Children were diagnosed with DTE when they had at least one delayed permanent tooth, according to age of exfoliation of each tooth proposed by The American Dental Association. Genomic DNA from saliva was used to evaluate the SNPs in ESR1 (rs9340799 and rs2234693) and ESR2 (rs1256049 and rs4986938) using Real-Time PCR. Chi-square or Fisher exact tests and Logistic Regression adjusted by age and gender were performed. SNP-SNP interaction was accessed by multifactor dimensionality reduction (MDR) analysis also adjusted by gender and age. The established alpha of this study was 5%. Among 537 included children, 296 (55%) were in the "DTE" group and the 241 (45%) were in the "Control" group. Age and gender were not statistically different among the groups (p>0.05). Genotype distribution of the SNPs rs9340799, rs2234693, rs1256049 and rs4986938 were not associated with DTE (p> 0.05). The models elected by MDR were not statistically significant either. Conclusions: The studied SNPs in ESR1 and ESR2 were not associated with permanent DTE.

Alveolar bone pathology associated with delayed permanent tooth eruption in a cat – a case study

A young cat was presented with oral discomfort, gingival swelling and delayed eruption of the permanent dentition. Radiography confirmed the presence of unerupted teeth and identified alveolar bone pathology. Operculotomy was performed to expose the embedded teeth. Eruption and the potential etiology of disturbances to normal dental eruption are discussed.

Validating clinical characteristic of primary failure of eruption (PFE) associated with PTH1R variants

BACKGROUND

Primary failure of eruption (PFE) is a hereditary condition, and linkage with variants in the PTH1R gene has been demonstrated in many cases. The clinical severity and expression of PFE is variable, and the genotype-phenotype correlation remains elusive. Further, the similarity between some eruption disorders that are not associated with PTH1R alterations is striking. To better understand the genotype-phenotype correlation, we examined the relationship between the eruption phenotype and PTH1R genotype in 44 patients with suspected PFE and 27 unaffected relatives. Sanger sequencing was employed to analyze carefully selected PFE patients. Potential pathogenicity of variants was evaluated against multiple genetic databases for function prediction and frequency information.

RESULTS

Mutational analysis of the PTH1R coding sequence revealed 14 different variants in 38 individuals (30 patients and 8 first-degree relatives), 9 exonic and 5 intronic. Their pathogenicity has been reported and compared with the number and severity of clinical signs. In 72.7% of patients with pathogenic variants, five clinical and radiographic criteria have been found: involvement of posterior teeth, involvement of the distal teeth to the most mesial affected, supracrestal presentation, altered vertical growth of the alveolar process and posterior open-bite. In cases with mixed dentition (3), the deciduous molars of the affected quadrant were infraoccluded.

DISCUSSION

The probability of an affected patient having a PTH1R variant is greater when five specific clinical characteristics are present. The likelihood of an eruption defect in the absence of specific clinical characteristics is rarely associated with a PTH1R mutation.

CONCLUSIONS

We report here that systematic clinical and radiographic observation using a diagnostic rubric is highly valuable in confirming PFE and offers a reliable alternative for accurate diagnosis.

Oral manifestations of congenital Zika virus infection in children with microcephaly: 18-month follow-up case series

AIMS

To describe oral manifestations in children born with microcephaly attributed to congenital Zika virus syndrome (CZS).

METHODS

Data was collected in semiannual intervals from 2017 to 2019, by oral exams of the children and interview with caregivers at a Public Dental Center in Rio de Janeiro, Brazil. A single calibrated examiner performed clinical examinations.

RESULTS

Of 38 eligible children, 34 were followed-up from 12 to 30 months of age, 20 boys and 14 girls. The mean age of emergence of their first primary tooth was 12.4 months (SD = 2.9). By 30 months of age only 14.7% (n = 5) had complete primary dentition. Alteration in the sequence of tooth emergence was observed in 41.1% (n = 14). Radiographic examination demonstrated dental agenesis (14.7% n = 5). Dental developmental alterations (38.2%, n = 13), enamel defects (14.7%, n = 5), eruption cysts/hematoma (23.5%, n = 8), gingival bleeding (55.8%, n = 19), narrow palate, and bruxism (64.7%, n = 22) were also observed. No child had dental caries.

CONCLUSION

Children with microcephaly attributed to CZS presented oral manifestations early in life.

The Correlation between Impacted Third Molar and Blood Group

Background

Blood type is among the most important genetical characteristics of any individual and is shown to be correlated with the development of a variety of illnesses including dental diseases. Finding the association of ABO and Rh blood groups and impacted tooth is important in order to predict which population is more vulnerable to grow impacted third molars that could lead to making better intervention. The present investigation tried to take a small step in that regard, by evaluating the correlation between ABO and Rh blood groups and the most commonly impacted tooth, bony impacted third molars among Iranian individuals.

Methods

The investigation was done retrospectively on patients who were referred to the Department of Oral Radiology, Shiraz University of Medical Science, Shiraz, Iran. The patients were classified according to their blood groups, and 40 patients were randomly selected for each blood type. Therefore, the impaction of their third molars was evaluated, and statistical analyses were done in order to find any association.

Results

A total of 320 participants contributed to the study; 136 (42%) were males and 184 (57%) were females. The mean age was 29 ± 6 years. Among all participants, 205 (64%) had no impacted third molar, 26 (8%) had one impacted third molar, 43 (13%) had 2 impacted third molars, 5 (1%) had 3 impacted third molars, and 41 (12%) had 4 impacted molars.

Conclusion

According to the results of the present study, nearly one out of three individuals has at least an impacted third molar in the Iranian population, being more prevalent in individuals between 20 and 30 years old. The evaluation of the relationship between the blood group and impacted third molar revealed that blood groups have no association with the impacted third molars. However, more studies with higher and diversified participants should be done to find comprehensive results.

Vitamin D deficiency is a risk factor for delayed tooth eruption associated with persistent primary tooth

OBJECTIVE

To verify the association between 25(OH)D level and polymorphisms in the vitamin D receptor gene (VDR) with the disturbance in the dental development and eruption.

DESIGN

A total of 183 children from two datasets were evaluated. The first dataset was a case-control (15:15) designed to assess if persistent primary tooth (PPT) is associate with serum 25(OH)D level and with genetic polymorphisms in VDR. The second dataset of genomic DNA samples from 54 children with delayed tooth eruption (DTE) and 99 controls were analysed to verify if genetic polymorphisms in VDR (rs2228570 and rs739837) are associated with DTE. The 25(OH)D and the genotyping/allele distribution were analysed using the T-test and chi-square test, respectively.

RESULTS

The level of 25(OH)D in the PPT group (24.9 ± 6.4 mg/mL) was significantly lower than the control (30.0 ± 7.0 mg/mL) (p=.047). Our data show that children with 25(OH)D deficiency are more likely to present PPT (OR = 2.36; 95%CI: 1.51, 3.70). The rs739837 and rs2228570 polymorphisms were not associated with DTE (OR = 1.44; 95%CI: 0.87, 2.39 and OR = 0.80; 95%CI: 0.45, 1.44, respectively).

CONCLUSIONS

Vitamin D deficiency is a risk factor for PPT.

An assessment of root stage of canine and premolar teeth at alveolar eruption

OBJECTIVE

The primary aim was to evaluate the degree of root development of permanent canines at the time of alveolar eruption. We also aimed to assess whether differences in the degree of root development at alveolar eruption exist between permanent canines and premolars and between maxilla and mandible.

DESIGN

A cross-sectional study.

SETTING

Barts and The London School of Medicine and Dentistry, Queen Mary University of London.

PARTICIPANTS

Two hundred dental panoramic radiographs taken as part of routine dental care.

METHODS

Radiographs were assessed for canine and premolar root development stage and eruption level with calibration and repeat measurements undertaken.

RESULTS

Two hundred and sixty teeth were identified as being at the level of alveolar eruption. The majority of maxillary canines reached alveolar eruption when root formation was complete. Most premolars and mandibular canines reached alveolar eruption when roots were three-quarters developed. At alveolar eruption, canines were statistically more mature than premolars (p<0.001) and maxillary teeth were more mature than mandibular teeth (p<0.05).

CONCLUSIONS

Root development appears to be particularly advanced for maxillary permanent canines, being essentially root-complete at alveolar eruption, while premolars and mandibular permanent canines appear to have three-quarters root development at this stage. This information may be used to inform whether and when to extract primary teeth for orthodontic reasons.

Revisiting the human dental follicle: From tooth development to its association with unerupted or impacted teeth and pathological changes

Dental follicles are involved in odontogenesis, periodontogenesis, and tooth eruption. Dental follicles are unique structures, considering that their remnants can persist within the jawbones after odontogenesis throughout life if the tooth does not erupt. Pathological changes may occur in these tissues as individuals age. The changes range from benign to life threatening. Thus, the assessment of age-related changes in dental follicles associated with unerupted teeth is of paramount importance. In this review, we summarize the physiological roles and changes in dental follicles in odontogenesis, tooth eruption, and aging, in addition to the pathological changes associated with these structures. We encourage investigators to consider this peculiar tissue as a unique model and explore its potential to clarify its importance from the viewpoints of developmental biology, tissue physiology, and pathology.

Overview of Radiological Studies on Visualization of Gubernaculum Tracts of Permanent Teeth

The eruption pathway from the dental follicle to the gingiva for permanent teeth is known as the gubernaculum tract (GT), a physiologic structure thought to play a role in tooth eruption. Cone beam computed tomography and multi-detector computed tomography have recently been used to visualize the GT, with the results indicating that this structure might be related to the normal eruption of teeth. By contrast, curved and/or constricted GTs may lead to abnormal tooth eruption. In addition, complex odontomas have been reported from within the GT or dental sac of unerupted permanent teeth. If an odontoma occurs within the GT, the tooth will not erupt normally. Moreover, the imaging characteristics of the GT from the top of the odontogenic mass to the alveolar crest are extremely useful for making a differential pathological diagnosis and for differentiating between odontogenic and non-odontogenic masses. Therefore, radiological studies on the GT have been attracting increasing attention. Given this background, the present review aims to clarify the imaging characteristics and review recent studies on the GT considering the importance of the research.

Observing the Eruption of Canine After Secondary Alveolar Bone Grafting

PURPOSE

Alveolar bone grafting is undertaken to provide stability to the dental arch and facilitate the eruption of permanent canine as teeth in the line of cleft usually have an altered pattern of eruption. The purpose of this study was to assess the eruption status and the change in the position and pattern of canine eruption after secondary alveolar bone grafting.

METHODS

An ambispective cohort study was conducted in patients operated for alveolar bone grafting with unilateral/bilateral alveolar cleft between the age of 9 to 13 years using autogenous iliac crest bone graft. The predictor variables of interest include the preoperative eruption status of canine (completely erupted/partially erupted/unerupted), stage of root development (one-third/two-third/more than two-third/complete) and position (vertical/lateral/buccopalatal) of the canine. The primary outcome variable is the eruption status of the canine (completely erupted/partially erupted/unerupted) at 6 months postoperatively. Secondary outcome variables include the stage of root development, change in the vertical, lateral and buccopalatal position of the canine observed in the first 6 months postoperatively with follow-up at 1 and 3 months. Another secondary outcome variable was the status of bone graft at 6 months postoperatively. Statistical analysis was done using Spearman's rank correlation and ANOVA chi-square test.

RESULT

The study sample consisted of 30 non-syndromic alveolar cleft patients with a mean age of 11.9 years, out of which partial and complete eruption of canine was seen in 43.33 and 36.67%, respectively. The canine was unerupted in 20% of the cases (P = .001). There was evidence of continued root development through the grafted bone. No significant change in the angulation of canine was observed in the postoperative period.

CONCLUSION

Significant change in the eruption status and root development of canine with no statistically significant change in the vertical and lateral angulation during eruption was observed. Identifying these risk factors by continuous postoperative monitoring will help in identifying the malposition at an early stage.

Phenotypic Plasticity in Vertebrate Dentitions

Vertebrates interact directly with food items through their dentition, and these interactions with trophic resources could often feedback to influence tooth structure. Although dentitions are often considered to be a fixed phenotype, there is the potential for environmentally induced phenotypic plasticity in teeth to extensively influence their diversity. Here, we review the literature concerning phenotypic plasticity of vertebrate teeth. Even though only a few taxonomically disparate studies have focused on phenotypic plasticity in teeth, there are a number of ways teeth can change their size, shape, or patterns of replacement as a response to the environment. Elucidating the underlying physiological, developmental, and genetic mechanisms that generate phenotypic plasticity can clarify its potential role in the evolution of dental phenotypes.