Prevalence of short-root anomaly in healthy young adults

Comparative assessment of orthodontic clear aligner versus fixed appliance for anterior retraction: a finite element study

BACKGROUND

The aim of this study is to conduct a comparative evaluation of different designs of clear aligners and examine the disparities between clear aligners and fixed appliances.

METHODS

3D digital models were created, consisting of a maxillary dentition without first premolars, maxilla, periodontal ligaments, attachments, micro-implant, 3D printed lingual retractor, brackets, archwire and clear aligner. The study involved the creation of five design models for clear aligner maxillary anterior internal retraction and one design model for fixed appliance maxillary anterior internal retraction, which were subsequently subjected to finite element analysis. These design models included: (1) Model C0 Control, (2) Model C1 Posterior Micro-implant, (3) Model C2 Anterior Micro-implant, (4) Model C3 Palatal Plate, (5) Model C4 Lingual Retractor, and (6) Model F0 Fixed Appliance.

RESULTS

In the clear aligner models, a consistent pattern of tooth movement was observed. Notably, among all tested models, the modified clear aligner Model C3 exhibited the smallest differences in sagittal displacement of the crown-root of the central incisor, vertical displacement of the central incisor, sagittal displacement of the second premolar and second molar, as well as vertical displacement of posterior teeth. However, distinct variations in tooth movement trends were observed between the clear aligner models and the fixed appliance model. Furthermore, compared to the fixed appliance model, significant increases in tooth displacement were achieved with the use of clear aligner models.

CONCLUSIONS

In the clear aligner models, the movement trend of the teeth remained consistent, but there were variations in the amount of tooth displacement. Overall, the Model C3 exhibited better torque control and provided greater protection for posterior anchorage teeth compared to the other four clear aligner models. On the other hand, the fixed appliance model provides superior anterior torque control and better protection of the posterior anchorage teeth compared to clear aligner models. The clear aligner approach and the fixed appliance approach still exhibit a disparity; nevertheless, this study offers a developmental direction and establishes a theoretical foundation for future non-invasive, aesthetically pleasing, comfortable, and efficient modalities of clear aligner treatment.

Presentation of a Case of Short Root Anomaly in an 11-Year-Old Child

Short root anomaly (SRA) is a developmental anomaly in which the affected teeth present morphologically normal crowns and short, round roots. The exact cause of SRA is unknown. A case of an 11-year-old female patient with SRA is described. The patient presented short, round roots of all permanent teeth but first molars. Maxillary lateral incisors presented severe root resorption and mobility. Treatment plan included preservation of the maxillary lateral incisors by splinting them to their adjacent teeth using a stainless steel coaxial wire. A custom mouthguard for dental trauma protection was also constructed using a computer-aided design - computer-aided manufacturing (CAD-CAM) system in order to fabricate 3D-printed dental casts. At 2-year follow-up, the mobility of maxillary lateral incisors decreased, and the patient's dentition remained stable. Considerations regarding differential diagnosis, orthodontic management, and treatment options after an eventual loss of teeth are thoroughly discussed.

Oral characteristics in adult individuals with periodontal Ehlers-Danlos syndrome

AIM

Periodontal Ehlers-Danlos syndrome (pEDS) is a monogenic type of Ehlers-Danlos syndrome characterized by periodontal destruction at a young age. The present study aimed to document the oral phenotype of pEDS based on prospective clinical investigations.

MATERIALS AND METHODS

Thirty-five adult individuals from 13 families with a clinically and genetically confirmed diagnosis of pEDS underwent a systematic oral assessment.

RESULTS

Periodontitis stage 3 or 4 or edentulism due to periodontal destruction were diagnosed in 94% of the individuals. First permanent tooth loss was reported at the age of 21.5 years (median; range 13-43 years). Deep periodontal pockets were infrequent, with 94% measuring <4 mm. However, there was increased clinical attachment loss (CAL) averaging 8 mm (range 4-13 mm), and the probability of being edentate between the age of 35 and 44 years was 28-47% compared with less than 0.25% of the general population. Radiographic anomalous findings were only found in a portion of subjects and consisted of fused roots of maxillary second molars (81%), root hypoplasia (57%), taurodontism (26%) and tooth rotation of premolars (67%). As such, radiographic findings are not considered common characteristics of pEDS.

CONCLUSIONS

Characteristic oral traits of pEDS in adults are severe CAL with shallow probing depths and marked gingival recession. This is complemented by a lack of attached gingiva. These indications need to be paralleled by genetic analyses to diagnose pEDS unambiguously.

Interventive dental therapy in Ancient Egypt (ca. 2686 BCE - AD 323): A critical review

OBJECTIVE

This paper critically reviews the history of research concerning ancient Egyptian interventive dental therapy between the Old Kingdom - Graeco-Roman Period (c. 2686 BCE-AD 323), concentrating on the published osteological evidence.

MATERIALS

Eight osteological examples reportedly exhibiting markers of interventive dental therapy, including a mandible presenting purported evidence for a drilling procedure for the relief of an abscess; four dental bridges; a maxilla with multiple teeth extracted; and two carious lesion fillings.

METHODS

Previous claims are critically reviewed using a qualitative research method involving collecting and critiquing published data, both primary evidence and relevant secondary literature.

CONCLUSIONS

Without further scientific analysis, only four specimens can currently be plausibly attributed to ancient Egyptian interventive dental therapy including the Tura el-Asmant Bridge, the enucleation described for a Graeco-Roman child, and two carious lesion fillings identified in the mummified individuals known as the 'Redpath Mummy' (RM2718) and 'Sekhem' (AIG3343).

SIGNIFICANCE

Several enduring historiographical and museological problems within the discourse are identified, revising our understanding of the nature and scope of ancient Egyptian interventive dental therapy based on currently known osteological evidence.

LIMITATIONS

This review relies on the published documentation for each osteological example, namely images, which in several cases are poor quality.

SUGGESTIONS FOR FURTHER RESEARCH

There is significant opportunity for further scientific analysis of the osteological evidence discussed. In each case, specific potential methods to improve our understanding and interpretation have been identified.

Prevalence of Developmental Dental Anomalies of Number and Size in Indian Population According to Age and Gender

Introduction

Dental anomalies arise due to genetic and environmental factors in the morphodifferentiation stage of odontogenesis lead to alteration in the number and size of the tooth as well as the root.^1–3 The knowledge of their prevalence and the extent of involvement can provide valuable information for phylogenic and genetic studies and also help in the understanding of differences among the population and between various population groups.⁴ We aim to identify the prevalence and distribution of such anomalies according to age and gender. The acquired details of cases will further help the dental clinicians to understand their etiology which can further facilitate their diagnosis and effective management. Also, timely intervention can be achieved.

Materials and methods

Retrospective study of 4,000 subjects (equal proportion of males and female) of age range from 10 to 40 years were studied. Their radiographs, dental casts, and clinical findings were evaluated for number and size developmental dental anomaly.

Results

Incidence of overall 331 cases (8.27%) of number and size developmental dental anomalies were recorded with 173 (8.6%) males and 158 (7.9%) females. Hypodontia was the most frequently found dental anomaly in both males (4.9%) and females (4.4%) followed by hyperdontia and supernumerary roots. Microdontia was the most frequently found size anomaly in both males (1.6%) and females (1.9%).

Conclusion

Hypodontia (4.7%) is the most frequently found numeral anomaly in both males and females. Intergroup study shows a significant statistical difference in cases of hypodontia in the 10–25 years of age-group (6.2%) with a p value ≤ 0.00001.

How to cite this article

Jain A, Saxena A, Jain S, et al. Prevalence of Developmental Dental Anomalies of Number and Size in Indian Population According to Age and Gender. Int J Clin Pediatr Dent 2021;14(4):531–536.

Association between Smoking during Pregnancy and Short Root Anomaly in Offspring

Short root anomaly (SRA) is a dental anomaly with short dental roots and its pathogenesis is poorly understood. This study investigated the association between maternal smoking during pregnancy and SRA in offspring. A survey was conducted on 558 children aged 8–16 years from two public schools in Ulaanbaatar, Mongolia. SRA was diagnosed using cases with a root-crown ratio of maxillary central incisors of ≤1.0. A questionnaire survey was conducted to assess maternal lifestyle habits. Multiple logistic regression was used to analyse the association between maternal smoking during pregnancy and SRA in offspring after adjusting for possible confounders. The prevalence of SRA in these children was 14.2%. Children whose mothers smoked from pregnancy to date were found to be 4.95 times (95% confidence interval [CI]: 1.65–14.79) more likely to have SRA than those whose mothers never smoked, after adjusting for possible confounders. Additionally, children whose mothers had been exposed to passive smoking during pregnancy were found to be 1.86 times (95% CI: 1.02–3.40) more likely to have SRA than those whose mothers had not been exposed to passive smoke. Our population-based study suggests that maternal and passive smoking exposure during pregnancy can affect tooth root formation in children.

Long-Term Effects of Childhood Cancer Treatment on Dentition and Oral Health: A Dentist Survey Study from the DCCSS LATER 2 Study

Simple Summary

We aimed to identify the prevalence of and independent risk factors for dental and oral problems in childhood cancer survivors (CCSs). This cross-sectional study is part of the Dutch Childhood Cancer Survivor Study (DCCSS) LATER 2. Our study included survey data on 154 CCSs, on whom information from dentists on oral health data was received (71.3%). In total, 36.3% of survivors were reported to have at least one dental developmental disorder (DDD). The most prevalent DDDs were short-root anomaly (14.6%), agenesis (14.3%), and microdontia (13.6%). Risk factors for at least one DDD were younger age at diagnosis (<3 years vs. 5+ years) and dose-dependent alkylating agent therapy. This study provides more insight into risk factors for oral health problems in Dutch CCSs. This information is essential in order to improve early detection, prevention, and dental care of oral health problems in CCSs.

Abstract

Objectives: The aim of this study was to identify the prevalence of and independent risk factors for long-term effects of childhood cancer treatment on the dentition and oral health in childhood cancer survivors (CCSs). Methods: This cross-sectional study is part of the Dutch Childhood Cancer Survivor Study (DCCSS) LATER 2. CCSs were diagnosed with cancer between 1963 and 2001. This study focuses on survey data of 154 CCSs on whom information about their oral health was received from their dentists (71.3%). Descriptive statistics and univariable and multivariable Poisson regression analyses were performed to determine the association between treatment characteristics and oral health data. Results: Of the study group, 36.3% had at least one DDD. The most prevalent DDDs were short-root anomaly (14.6%), agenesis (14.3%), and microdontia (13.6%). Risk factors for at least one DDD were younger age at diagnosis (<3 years) and dose-dependent alkylating agent therapy. Conclusions: This study provides more insight into risk factors for oral health problems in Dutch CCSs. This information is essential in order to improve early detection, prevention, dental care, and quality of life. Further studies are needed in order to better define dose-related radiotherapy exposure of the developing teeth in correlation with oral health problems.

Effect of orthodontic forces on root length of immature mandibular second premolars: a split-mouth randomized clinical trial

Objective:

To assess the effect of orthodontic forces on changes in root length of immature mandibular second premolars.

Methods:

Sixty-four mandibular second premolars (MSP) with immature apices (left and right sides) of 32 patients aged between 10 and 13 years were evaluated. Orthodontic treatment was started after obtaining periapical radiographs (T₁) from the MSPs of each patient. Brackets were bonded, except the ones of MSPs (left or right by random as control MSP, and the other side as test MSP). After 9-12 months, a second periapical radiograph (T₂) was obtained from the MSPs of each patient. Then, brackets were bonded to the control MSPs, which were not bonded before. After 18 ± 3 months, a third periapical radiograph (T₃) was obtained. Changes in root length were evaluated by using a new formula. The test and control MSPs at T₁, T₂ and T₃ were compared using repeated measures ANOVA and parametric tests. P-value smaller than 0.05 was statistically significant.

Results:

There was no significant difference between the test and control groups in the mean root length of MSP at T₁ (p= 0.48) and T₃ (p= 0.078). The root length at T₂ (p= 0.001) was significantly different between test and control MSPs, and the test group showed longer root length than the control group.

Conclusions:

Orthodontic force applied for leveling and alignment of immature MSPs may not have destructive effects on the roots, and may accelerates root formation in short-term. Normal root length was achieved at the end of root development.

Molecular mechanisms for short root anomaly

Short root anomaly (SRA) is a dental disorder that presents an abnormal root morphology with short and blunt dental roots. In this situation, many dental treatments face a difficult challenge, especially orthodontic and prosthodontic treatments. Therefore, an understanding of how SRA develops is urgently needed. Here we describe that the abnormal expression of nuclear factor I C-type (Nfic), osterix (Osx), hedgehog (Hh), bone morphogenetic proteins (BMPs), transforming growth factor-β (TGF-β), Smad, Wnt, β-catenin, and dickkopf-related protein 1 (DKK1) leads to SRA. These factors interact with each other and constitute complicated signaling network in tooth formation. Specifically, BMP signaling inhibits the activity of Wnt/β-catenin directly or by inducing Osx via Runx2-dependent and Runx2-independent pathways. And Osx is a main inhibitor of Wnt/β-catenin signaling. In return, Wnt/β-catenin signaling has an antagonistic action of BMP pathway and a stimulation of Runx2. We highlight the importance of Wnt/β-catenin signaling in the pathological mechanisms. Either suppression or overactivation of this signaling influences the normal odontogenesis. Finally, we list rescue experiments on animal models, which have been reported to restore the interrupted cell differentiation and impaired tooth formation. We hope to find potential treatments for SRA based on these evidences in the future.

Orthodontic management of a patient with short root anomaly and impacted teeth

Short root anomaly (SRA) is a rare familial dental condition that is often misdiagnosed. Orthodontic treatment of patients with SRA is challenging because it is difficult to diagnose, it may be accompanied by other dental anomalies, and it has been reported to contribute to additional susceptibility to root resorption during orthodontic treatment. In this article, we describe a methodical and evidence-based means of diagnosing and orthodontically managing a patient with SRA. The patient had additional challenges, including impacted and ectopic teeth. An individualized treatment plan that incorporated efficient and effective mechanics led to a well seated occlusion and an esthetic smile.

ADAM28 dramatically regulates the biological features of human gingival fibroblasts

This study was to explore the effects of a disintegrin and metalloproteinase 28 (ADAM28) on the proliferation, differentiation, and apoptosis of human gingival fibroblasts (HGFs) and probable mechanism. After ADAM28 antisense oligodeoxynucleotide (AS-ODN) and sense oligodeoxynucleotide (S-ODN) were transfected into HGFs by Lipofectamine 2000, respectively, the expression discrepancies of ADAM28 among various groups were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and Western-blotting. Methabenzthiazuron (MTT) and cell-cycle assays were used to test the HGFs proliferation activity. Annexin V fluorescein isothiocyanate (FITC)/propidium iodide (PI) and alkaline phosphatase (ALP) analysis were performed separately to measure apoptosis and the cytodifferentiation standard. Immunocytochemistry and Western-blotting were carried out to determine the influence of ADAM28 AS-ODN on HGFs expressing core binding factor α1 (Cbfα1), cementum protein 1 (CEMP1), osteopontin (OPN) and dentin matrix protein 1 (DMP1). The AS-ODN group displayed the lowest expression level in HGFs, meanwhile the ADAM28 S-ODN group showed the highest. Furthermore, blocking of ADAM28 could inhibit the proliferation of HGFs, enhance HGFs differentiation and induce apoptosis of HGFs. Whereas, overexpression of ADAM28 generated the opposite effects and inhibited apoptosis. ADAM28 AS-ODN was able to notably suppress the expressions of Cbfα1 and CEMP1, and ADAM28 had positive correlations with cbfα1 and CEMP1. These provided conspicuous evidence that ADAM28 may play a crucial role in root development as a potential regulator of growth, differentiation, and apoptosis of HGFs.

Short Root Anomaly - A Potential "Landmine" for Orthodontic and Orthognathic Surgery Treatment of Patients

Short root anomaly (SRA) is a poorly understood developmental disorder and can significantly compromise the patient's dental treatment. This case report describes the treatment of a 15-year-old girl with SRA and discusses the implication of this disorder on orthodontic and orthognathic treatment of patients.

Dental anomalies in an orthodontic patient population with maxillary lateral incisor agenesis

Introduction:

The purpose of this study was to evaluate the prevalence of dental anomalies in a subpopulation of orthodontic patients with agenesis of maxillary lateral incisors (MLI).

Methods:

The material of the present study included the records of the 1964 orthodontic patients. Panoramic radiographs and dental casts were used to analyze other associated eight dental anomalies, including agenesis of other teeth, dens invaginatus, dens evaginatus, peg shaped MLI, taurodontism, pulp stone, root dilaceration and maxillary canine impaction.

Results:

Out of the 1964 patients examined, 90 were found to have agenesis of MLI, representing a prevalence of 4.6%. The most commonly found associated-anomalies were agenesis of other teeth (23.3%), peg-shaped MLIs (15.6%), taurodontism (42.2%), and dilacerated teeth (18.9%).

Conclusion:

Permanent tooth agenesis, taurodontism, peg-shaped maxillary lateral incisor, and root dilacerations are frequently associated with maxillary lateral incisor agenesis.

Stunted root development: A rare dental complication of Stevens-Johnson syndrome

Stevens-Johnson syndrome (SJS) is a severe cutaneous reaction seen rarely in clinical practice. Most often, it occurs as an adverse reaction to certain drugs. When it affects children at a very young age, arrested tooth root development may also be seen. We present a case of a 13 year old boy who suffered from SJ syndrome at the age of 7 years. Incomplete root development was observed in all teeth, as demonstrated by panaromic radiography. Clinical features of this condition and its management are further discussed. We aim to emphasise on the need for dental practitioners to be aware of the potential dental complications of SJS and enable them to recognise and manage the condition at the earliest so as to avoid any undesirable sequelae.

Key words:Adverse drug reaction, amoxycillin, arrested root development, Stevens-Johnson syndrome.

Dental Anomalies as Late Adverse Effect among Young Children Treated for Cancer

Purpose

The aim of this study was to compare the incidence of dental complications in childhood cancer survivors with that of healthy control subjects, and to determine the possible influence of various factors associated with patient and treatment.

Materials and Methods

Sixty-one panoramic radiographs of the dentition of cancer survivors were compared with 521 radiographs of healthy patients at a similar age, between 5 and 18 years. The mean period from termination of therapy was 4.9 years (58.9±34.3 months), and 51 children (83.60%) were under age 5 when therapy began.

Results

Dental anomalies were found in 38 cancer survivors (62.29%) and 69 control subjects (13.24%) (p < 0.001). Agenesis of teeth was found in 19 cancer patients (31.14%) and in 48 control subjects (9.21%). Microdontic teeth were found in 22 cancer survivors (36.06%) and 15 control subjects (2.87%) (p < 0.001), whereas teeth with short roots were found in seven cancer patients (11.47%) and 15 control subjects (2.87%) (p < 0.01). Dental anomalies in cancer patients were more common in some tooth groups and were not observed in others. The frequency of dental anomalies did not show correlation with age at the beginning or termination or time of therapy.

Conclusion

Children under the age of 5 are in a high risk group for dental complications after anticancer treatment. Rudimentary chemotherapy has a considerable impact on the occurrence of dental anomalies.

Orthodontic movement of teeth with short root anomaly: Should it be avoided, faced or ignored?

INTRODUCTION

Short Root Anomaly (SRA) is an uncommon disease and a challenge for orthodontic treatment as it tends to increase the risk of root resorption.

OBJECTIVE

Assess the current status of the diagnosis, etiology and orthodontic management of teeth with SRA, and present case reports.

METHODS

A literature review was carried out in PubMed, SciELO, LILACS, Scopus and Web of Science databases.

RESULTS

A differential diagnosis of SRA should be conducted for teeth with incomplete root formation, external apical root resorption, dentin dysplasia type I and post dental trauma root hypoplasia. SRA is genetically determined and orthodontic movement requires changes in clinical and radiographic management in order to restrict damage.

CONCLUSIONS

Orthodontic movement of teeth with SRA is contraindicated in extreme cases, only. Caution at all stages could minimize attachment loss and lead to long-term stability.

Regulatory mechanisms of Hertwig׳s epithelial root sheath formation and anomaly correlated with root length

Teeth are composed of two domains, the enamel-covered crown and cementum-covered root. The mechanism for determining the transition from crown to root is important for understanding root anomaly diseases. Hertwig׳s epithelial root sheath (HERS) is derived from the dental epithelium and is known to drive the growth of root dentin and periodontal tissue. Some clinical cases of hypoplastic tooth root are caused by the cessation of HERS development. Understanding the mechanisms of HERS development will contribute to the study of the disease and dental regenerative medicine. However, the developmental biology of tooth root formation has not been fully studied, particularly regarding HERS formation. Here, we describe the mechanisms of HERS formation on the basis of analysis of cell dynamics using imaging and summarize how the growth factor and its receptor regulate cell behavior of the dental epithelium.

Case reports of orthodontic treatment of maxillary central incisors with short roots

Maxillary central incisors with short roots are occasionally encountered during orthodontic diagnosis. From an esthetic point of view, the central incisors occupy the most noticeable position in the maxillary and mandibular arches, and whether or not to extract them marks a major turning point in the planning of orthodontic treatment. In deciding a treatment strategy in this situation, there are two options to be considered: 1) treatment without extraction due to esthetic considerations; or 2) extraction, taking risk and prognosis into account. Whichever strategy is adopted, however, it will still be necessary to bear in mind that the treatment and prognosis will differ from that in normal orthodontic treatment. If no extraction is to be carried out, care must be taken that no further shortening occurs during the course of active treatment and that stable retention is preserved. On the other hand, if the central incisors are to be extracted, care must be taken to ensure that this has no negative esthetic impact, either during or after orthodontic treatment.

Generalised stunting of roots in an epileptic child: is long-term phenytoin therapy the cause?

Long-term phenytoin therapy is known to cause disturbance in calcium and bone homeostasis. Dental tissues being calcified tissues can also be affected by this derangement of mineral metabolism, especially during developmental phases. This report describes a case of an epileptic child who presented with short roots, enlarged pulp chambers, blunt apices and delayed eruption of permanent dentition, which might be attributed to long-term phenytoin therapy. The purpose of this case report is to increase awareness among the clinicians about its possible dental implications and emphasise upon the need of regular dental check-ups in epileptic children.

Permanent mandibular incisor with multiple anomalies - report of a rare clinical case

Permanent mandibular central incisor is rarely affected by tooth shape anomalies of crown and root. Co-occurrence of multiple anomalies in a permanent mandibular central incisor is extremely rare. This paper reports an unusual concurrent combination of multiple dental anomalies affecting both the crown and root of a permanent mandibular left central incisor - talon cusp, dens invaginatus, short root anomaly and macrodontia -, which has not previously been reported together. Case management is described and implications are discussed. The dentist should be aware of these rare entities in order to provide an accurate diagnosis and management for which detailed examination of the tooth both clinically and radiographically is very important.

Crown-root ratio of permanent teeth in cleft lip and palate patients

OBJECTIVES

To determine root lengths of fully developed permanent teeth of cleft lip and palate (CLP) patients and to define their crown-root (C/R) ratios.

METHOD

Crown height and root length of permanent teeth were measured from panoramic radiographs of 44 CLP patients and 37 controls. A total of 1397 teeth were measured, and C/R ratios were calculated.

RESULTS

Higher C/R ratios were found in CLP patients; this was statistically significant for both maxillary and mandibular incisors and canines. Bilateral CLP subjects showed higher C/R ratios in general than unilateral CLP subjects. Roots of maxillary incisors, canines, and some other teeth were significantly shorter in CLP patients than in controls.

CONCLUSIONS

CLP patients should be considered to have unfavorable C/R ratios, which could be the result of short root lengths for some teeth.

Orthodontic force accelerates dentine mineralization during tooth development in juvenile rats

Malocclusion, the improper positioning of the teeth and jaws, is among the most important global oral health burdens. People with malocclusion may require orthodontic treatment to correct the problem. Orthodontic treatment is a way of straightening or moving teeth, to improve the appearance of the teeth and how they work. It is generally best carried out in children aged 9 to 12 years, whose teeth are mainly young permanent teeth with incomplete root formation. However, the relationship between orthodontic force and tooth development has not been fully understood. In this study, we sought to investigate the effects of orthodontic force on dentine formation and mineralization during the development of young permanent teeth. Standardized orthodontic tooth movement was performed with the orthodontic appliance in five-week-old rats. To obtain longitudinal assessment of dentine formation, tetracycline was administered on the operation day and 1, 3, 7, 14 or 21 days afterward. We found that the distance between two tetracycline stripes, which indicates the amount of dentine formation during orthodontic treatment, increased with time. Importantly, no significant difference was detected in dentine formation between treated and control rats. In contrast, immunohistochemical analysis showed that the expression of dentin sialoprotein, a marker of odontoblast differentiation and mineral apposition, was significantly elevated in crown and root dentine after orthodontic treatment. In conclusion, orthodontic treatment does not affect the dentine formation of young permanent teeth, but it promotes the activation of odontoblasts and accelerates the dentine mineralization. These results suggest the safety of early orthodontic treatment.

Influence of ADAM28 on biological characteristics of human dental follicle cells

OBJECTIVES

The aim of this study was to investigate the effects of a disintegrin and metalloproteinase 28 (ADAM28) on the biological characteristics of human dental follicle cells (HDFCs) and possible action mechanism.

METHODS

Eukaryotic expression plasmid containing ADAM28 coding region and ADAM28 antisense oligodeoxynucleotides (AS-ODN) with FITC labelling were constructed and synthesised by gene clone and recombination. Then we respectively transfected them into HDFCs by Lipofectamine 2000 system and detected their effects on proliferation, differentiation and apoptosis of HDFCs by MTT assay, cell cycle detection, ALP activity and Annexin V-FITC/PI analysis. Finally we observed the effects of ADAM28 AS-ODN on HDFCs expressing extracellular matrix (ECM) proteins by immunocytochemical staining.

RESULTS

ADAM28 eukaryotic plasmid was constructed and identified successfully, and could be correctly translated and expressed in HDFCs, furthermore overexpression of ADAM28 promoted the HDFCs proliferation and inhibited specific differentiation of HDFCs, while inhibition of ADAM28 exerted the opposite effects and induced apoptosis. Moreover ADAM28 could significantly inhibit the secretion of OPN and type III collagen of HDFCs.

CONCLUSIONS

ADAM28 might actively participate in the network regulation which associates HDFCs proliferation, differentiation, apoptosis with matrix mineralisation during tooth development by interacting with multiple signal molecules.

Prevalence of dental anomalies in various malocclusions

INTRODUCTION

The purpose of this study was to evaluate the prevalence of dental anomalies in different orthodontic malocclusions.

METHODS

Based on pretreatment diagnostic records, 900 orthodontic patients were classified as Class I (n = 358), Class II (n = 325), Class II Division 2 (n = 51), or Class III (n = 166). The occurrence rates of each dental anomaly were calculated as percentages of the total sample. Differences in incidence rates of each dental anomaly by sex and malocclusion were analyzed by using chi-square, Fisher exact, and z tests. The Mann-Whitney U test was used to determine whether there were significant differences in the occurrence of dental anomalies by age.

RESULTS

It was found that 40.3% of patients (n = 363) had at least 1 dental anomaly. Agenesis was the most common (21.6%), followed by dens evaginatus (6.2%), invaginatus (5.0%), pulp stones (4.2%), and impaction (2.9%). No statistically significant correlations were found between dental anomaly and type of malocclusion, with the exception of impaction and short or blunt roots (P <0.01 and P <0.05, respectively). The Mann-Whitney U test indicated no significant difference in dental anomalies by age.

CONCLUSIONS

A remarkably high rate of dental anomalies was recorded in orthodontic patients; therefore, orthodontists should carefully examine pretreatment records for dental anomalies to include their management in the treatment planning.

Long root of deciduous anterior teeth

A 24-year-old female Japanese patient presented with remarkably long roots of retained deciduous anterior teeth and permanent anterior teeth in the upper and lower jaw. Four lower anterior teeth were extracted for esthetic reasons. The patient had no apparent clinical syndrome related to the teeth or jaw, nor did there appear to be a family history of this condition. The extracted teeth and their lengths were as follows: the lower right deciduous lateral incisor was 25.55 mm long (root length, 18.95 mm); the lower left deciduous lateral incisor was 22.10 mm long (root length, 17.25 mm); the lower right deciduous canine was 27.95 mm long (root length, 20.60 mm); and the lower left deciduous canine was 23.90 mm long (root length, 17.65 mm).

NficGene Disruption Inhibits Differentiation of Odontoblasts Responsible for Root Formation and Results in Formation of Short and Abnormal Roots in Mice

BACKGROUND

Nuclear factor I genes play an important role in the development of the brain, lung, and roots of teeth. We had reported that Nfic-deficient mice form normal crowns, but abnormal roots of molar teeth. However, the mechanism by which the disruption of Nfic gene causes abnormal root formation remains unknown.

METHODS

To understand this mechanism, the root formation in Nfic-deficient mice was examined and compared to that of wild-type mice by morphological, immunohistochemical, and in situ hybridization analyses.

RESULTS

Nfic-deficient mice formed normal Hertwig's epithelial root sheath (HERS) but severely disrupted odontoblast differentiation, leading to the formation of aberrant odontoblasts in the early stage of root formation. They became dissociated and polygonal in shape, lost their orientation and polarity, and did not express dentin sialophosphoprotein. The abnormal roots contained trapped aberrant odontoblasts, thereby resembling osteodentin in overall morphology. No osteoclasts were associated with abnormal roots. Further, the abnormal roots exhibited a decreased number of cementoblasts and cementum formation on the root surface.

CONCLUSIONS

The loss of Nfic did not interfere with the formation of HERS, but it caused disrupted odontoblast differentiation, which resulted in the formation of short and abnormal roots, and decreased cementum. This finding suggests that root dentin is required for normal cementum formation. Therefore, Nfic may be a key regulator of root odontoblast differentiation and root formation.

Short root anomaly associated with Rothmund-Thomson syndrome

A case of short root anomaly in a patient with Rothmund-Thomson syndrome is reported. The syndrome is a rare genodermatosis characterized by poikilodermatous rash starting in infancy, associated with juvenile cataracts, small stature, skeletal abnormalities, dental malformations, and predisposition to skin and bone cancers. In this case, abnormally short roots were detected during radiographic examination, affecting a complete permanent dentition including partially erupted third molars. The report contains a short review of the current literature on Rothmund-Thomson syndrome.

An unusual combination of idiopathic generalized short-root anomaly associated with microdontia, taurodontia, multiple dens invaginatus, obliterated pulp chambers and infected cyst: a case report

Generalized diminished root formation is a rare condition leading to early loss of teeth. This report describes an unusual case of generalized short roots associated with microdontia, taurodontism of posterior teeth, and multiple dens invaginatus along with short stature in a 20-year-old man, who had lost several teeth because of spontaneous exfoliation.