Agenesis of second premolars and delayed dental maturation

Does third molar agenesis influence the second lower molar mineralization?

Different studies have established that the mineralization stages of the second mandibular molar can be used in forensic age estimation. Nowadays, the estimate's accuracy is an ethical concern, producing as few false positives (individuals incorrectly classified as older than a determined threshold) and false negatives (individuals incorrectly classified as younger than a determined threshold) as possible. Some have hypothesized that changes in teeth number may influence tooth mineralization, altering the age estimate process. This paper analyzes whether third molar agenesis affects the second mandibular molar mineralization time frame. To do so, 355 orthopantomograms were evaluated for third molar agenesis, and the second mandibular molar mineralization stage was assessed using the Demirjian stages. Student's t-test was used to compare the difference in the mean age at which the various stages of 37 mineralization were reached in the groups with and without third molar agenesis. The level of statistical significance was set at 5%. The results pointed to a delay in second mandibular molar mineralization in the case of agenesis, suggesting the need to consider this when estimating age using dental techniques.

Mesiodistal angulation and developmental stages of unerupted mandibular second premolars in nonsyndromic oligodontia

INTRODUCTION

Oligodontia is a serious developmental dental anomaly that requires long-term multidisciplinary treatment, but its clinical characteristics are not well understood because it is rare. This study evaluated the mesiodistal angulation and developmental stages of unerupted mandibular second premolars (MnP2s) in orthodontic patients with nonsyndromic oligodontia.

METHODS

Thirty-seven patients with oligodontia with at least 1 unerupted MnP2 in Demirjian's developmental stages between D and G were selected. Age- and sex-matched patients without tooth agenesis, excluding third molars, were selected as the control group. Mesiodistal angulation between the long axis of the available MnP2 and the mandibular plane was measured on panoramic radiographs.

RESULTS

The MnP2 was significantly more distally angulated in the oligodontia group than in the control group. The developmental stage of the MnP2 in the oligodontia group was significantly delayed (1.04 ± 0.26 years; 95% confidence interval, 0.53-1.55 years). No correlation between the mesiodistal angulation and the developmental stage of the MnP2 was found in both groups.

CONCLUSIONS

Significant distal angulation and delayed developmental stages of MnP2s were found in patients with nonsyndromic oligodontia compared with age- and sex-matched patients without agenesis of permanent teeth, excluding third molars. However, no significant correlation was found between them. Regardless of the severity of the distal angulation of MnP2, observing delayed dental development in each patient is important.

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.

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.

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.

Dental management of a pediatric patient with progressive familial intrahepatic cholestasis having dental anomalies: a case report and brief review of the literature

BACKGROUND

Progressive familial intrahepatic cholestasis is a heterogeneous group of disorders, leading to intrahepatic cholestasis, with the possibility of chronic liver failure and biliary cirrhosis. Oligodontia is either the manifestation of a specific syndrome or is non-syndromic. To the best of our knowledge, this is the first case report of type 3 progressive familial intrahepatic cholestasis and concurrent oligodontia, craniosynostosis, dens in dente, taurodontism, and delayed permanent dentition in the medical and dental literature.

CASE PRESENTATION

We present the dental and medical histories and comprehensive dental management of a girl with type 3 progressive familial intrahepatic cholestasis and several dental anomalies, who was referred to a dental clinic due to severe dental caries and pain.

CONCLUSION

Our findings suggest that PFIC with manifestations as oligodontia, craniosynostosis, dens in dente, taurodontism, and delayed permanent dentition, might indicate an unknown syndrome; otherwise, the craniofacial anomalies are the manifestations of an independent disease coinciding with PFIC. Moreover, our case is a good example of the importance of timely medical and dental care in confining further health-related complications. The patient was able to ingest without any pain or discomfort after receiving proper dental management.

Association between dental agenesis and delay in dental development: a preliminary study in a Spanish paediatric population in relation with Dental Anomaly Pattern (DAP)

Background

The association between dental anomalies has been studied, giving rise to the concept of Dental Anomaly Pattern (DAP). Tooth agenesis has been associated with alterations such as molar infracclusion, taurodontism and delayed dental development. The aim of this study was to evaluate the dental development pattern in patients with non-syndromic dental agenesis, in comparison with a control group.

Methods

Dental and chronological age was analysed in a sample size of 204 orthopantomographs divided into a study group (n = 104) and a control group (n = 100) with the Demirjian Method. Intra and intergroup differences in chronological and dental age, and the correlation between them were calculated by statistical analysis with a 95% confidence level (p < 0.05).

Results

Dental age exceeded chronological age both in the control group and in the study group. Statistically significant differences (p = 0.004) were found when comparing the difference between chronological and dental age in the study (-0.16 ± 1.12) and control group (-0.58 ± 0.90). Regarding sex and age intergroup differences, the results were only statistically significant in the girls’ group (p = 0.017), and the age over 8 years old (p < 0.05). There were no significant differences in tooth development depending on the number of missing teeth or the affected tooth group, but there was a delay in the development of the homologous tooth contralateral to the absent one in 14.9% of patients.

Conclusions

The difference between chronological and dental age in permanent dentition is significantly lower in Spanish children with non-syndromic agenesis compared to a control group, presenting a lower dental age than chronological age than children without non-syndromic agenesis.

Comparison of three methods to estimate dental age in children

OBJECTIVES

In 1973, Demirjian and colleagues introduced a staging for tooth mineralization. Staging of the teeth of the left mandible generates a dental maturity score and an estimate of dental age. An update of this method was published in 2001 by Willems and colleagues. The London Atlas (2008) is another method used to assess dental age. This study compared the precision of these three methods for forensic age estimation.

MATERIALS AND METHODS

A total of 500 panoramic images of 251 boys and 249 girls aged 6-16 years had dental maturity evaluated by the same observer using the London Atlas and the methods of Demirjian and Willems. Individuals with syndromes potentially affecting dental maturation were excluded. The three methods were compared with respect to their precision in estimating chronological age.

RESULTS

Age estimates using Willems' method were significantly more precise than those obtained using Demirjian's method, while estimates obtained using the London Atlas method were comparable with both the others. The highest precision was obtained using the average of age estimates from Willems' method and the London Atlas.

CONCLUSIONS

To estimate age in individuals suspected of being below 16 years of age, we suggest first applying the London Atlas then computing age from the Demirjian stages of particular teeth using Willems' method, and finally using the average age estimate of both methods.

CLINICAL RELEVANCE

Combining the London Atlas and Willems' scoring method provides more precise estimates of dental age than the current practice of applying a single preferred method.

Prediction of agenesis of the mandibular second premolar using the developmental stages of the mandibular canine, first premolar, and second molar

OBJECTIVE

The aim in this study was to suggest a standard for early diagnosis of agenesis of the mandibular second premolars (L5) by estimating the developmental stages of the mandibular canines (L3), first premolars (L4), and second molars (L7).

DESIGN

Among all 5136 pediatric patients aged 5-11 years who received panoramic radiographs between June 2008 and December 2009 at Seoul National University Dental Hospital, 215 control patients and 74 agenesis patients who met inclusion criteria were analyzed. The developmental stages of all L3, L4, L5, and L7 of control and agenesis patients were estimated using the method proposed by Demirjian. To identify the tooth (L3, L4, L7) with the developmental pattern most similar to that of L5, Kendall rank correlation coefficients and Bootstrap method were used. To verify that patients with agenesis of L5 show delayed development, Wilcoxon rank sum test was used. To identify the stages in which to diagnose agenesis of L5, we performed survival analysis.

RESULTS

There was a significant correlation between the developmental stages of L3, L4, L7 and L5. The developmental stages of those three teeth in the agenesis group were delayed compared with those in the control group at certain ages. If the developmental stages of at least two of those three teeth reach Demirjian stage D without the calcification of L5, agenesis of L5 can be confirmed.

CONCLUSIONS

Agenesis of L5 can be confirmed when two of the three teeth (L3, L4, L7) reach Demirjian stage D.

Forensic age estimation based on development of third molars: a staging technique for magnetic resonance imaging

BACKGROUND

The development of third molars can be evaluated with medical imaging to estimate age in subadults. The appearance of third molars on magnetic resonance imaging (MRI) differs greatly from that on radiographs. Therefore a specific staging technique is necessary to classify third molar development on MRI and to apply it for age estimation.

AIM

To develop a specific staging technique to register third molar development on MRI and to evaluate its performance for age estimation in subadults.

MATERIALS AND METHODS

Using 3T MRI in three planes, all third molars were evaluated in 309 healthy Caucasian participants from 14 to 26 years old. According to the appearance of the developing third molars on MRI, descriptive criteria and schematic representations were established to define a specific staging technique. Two observers, with different levels of experience, staged all third molars independently with the developed technique. Intra- and inter-observer agreement were calculated. The data were imported in a Bayesian model for age estimation as described by Fieuws et al. (2016). This approach adequately handles correlation between age indicators and missing age indicators. It was used to calculate a point estimate and a prediction interval of the estimated age. Observed age minus predicted age was calculated, reflecting the error of the estimate.

RESULTS

One-hundred and sixty-six third molars were agenetic. Five percent (51/1096) of upper third molars and 7% (70/1044) of lower third molars were not assessable. Kappa for inter-observer agreement ranged from 0.76 to 0.80. For intra-observer agreement kappa ranged from 0.80 to 0.89. However, two stage differences between observers or between staging sessions occurred in up to 2.2% (20/899) of assessments, probably due to a learning effect. Using the Bayesian model for age estimation, a mean absolute error of 2.0 years in females and 1.7 years in males was obtained. Root mean squared error equalled 2.38 years and 2.06 years respectively. The performance to discern minors from adults was better for males than for females, with specificities of 96% and 73% respectively.

CONCLUSION

Age estimations based on the proposed staging method for third molars on MRI showed comparable reproducibility and performance as the established methods based on radiographs.

Prevalence of delayed tooth development and its relation to tooth agenesis in Korean children

OBJECTIVE

The aim of this study was to investigate the epidemiology of delayed tooth development (DTD) and the link between DTD and tooth agenesis (TA).

DESIGN

The dental maturity of all of the developing permanent teeth of 4611 children (2417 males and 2194 females) was evaluated from panoramic radiographs. The prevalence of DTD and TA was analyzed, and gender difference for DTS and TA was investigated. The correlation of DTD and TA was investigated in intra-fields and inter-fields.

RESULTS

The total prevalence of DTD among the 4611 children was 3.40%. The maxillary second premolar was the most frequently delayed tooth (1.02%), followed by the maxillary second molar (0.88%) and the mandibular second premolar (0.74%). DTD significantly correlated with TA in both intra-fields and inter-fields (p<0.05).

CONCLUSIONS

The field of delayed development exhibited a significant correlation with that of TA.

Dental development in patients with agenesis

AIM

Recent research concerning tooth development and dental agenesis suggests that specific genes are associated with agenesis, and that these genetic factors could also cause delayed dental development of the remaining teeth. The objective of this study was to evaluate whether dental development of patients with agenesis is delayed, compared to a control group.

SUBJECTS AND METHOD

Panoramic radiographs of 1145 patients with dental agenesis were collected (452 males, 693 females) aged 6.2 to 24.8 years. The control group included 2032 panoramic radiographs (977 males, 1055 females) aged 6.0 to 24.4 years. A total of 3177 orthopantomograms were staged according to Demirjian. All left permanent teeth present in the mandible (except third molars) were considered. In order to evaluate the difference between patients with and without agenesis, a developmental score (DS) was calculated. The association between the DS and the number of agenetic teeth was evaluated with a Spearman correlation.

RESULTS

Based on the DS, patients with agenesis have a delayed development compared to patients in the control group (p < 0.0001). Within the agenesis group, there is a weak relation between the number of agenetic teeth and the DS: the higher the number of teeth with agenesis, the lower the DS (p < 0.0001 and p = 0.06 for females and males, respectively).

CONCLUSION

The obtained results can be an important factor for treatment planning in patients with dental agenesis. Moreover, the presence of agenesis needs to be taken into account when using age estimation methods based on permanent tooth development.