Systemic disorders and their influence on the development of dental hard tissues: a literature review

Oral health and related outcomes in children and adolescents with cystic fibrosis: a scoping review

PURPOSE

Good oral health is important for children and adolescents with cystic fibrosis (CF). The purpose of this scoping review is to describe the existing evidence base regarding oral health in children and adolescents with CF and provide recommendations for future research.

METHODS

Using a scoping review framework, a comprehensive search was undertaken using medline, embase, and PubMed. The search strategy included broad terms relating to CF, oral health, and children and adolescents and included only papers written in English.

RESULTS

61 articles were included. Topics investigated included dental caries, enamel defects, periodontal health, dental staining, oral health related quality of life, dental management, and dental development of children and adolescents with CF.

CONCLUSION

Dental outcomes of children and adolescents with CF differ from the healthy population. The current literature describing dental health in children and adolescents with CF includes predominately descriptive analyses. A shift to hypothesis-based studies to explore causal relationships that explain the differences in dental outcomes seen in the CF population offers an opportunity to better understand the problems faced by children and adolescents with CF. Research that actively engages stakeholders, including children and adolescents with CF and their families will enable evidence-based recommendations to improve their oral health.

The Diagnosis and Initial Management of Children Presenting With Premature Loss of Primary Teeth Associated With a Systemic Condition

Background and objective Pediatric dentists face a serious challenge when encountering cases of primary teeth lost too soon due to systemic disorders such as diabetes mellitus, congenital heart disease, and chronic kidney disease. Prompt identification and treatment are necessary to minimize problems in these patients. This study aimed to better understand and enhance clinical outcomes in pediatric dentistry treatment by investigating diagnostic modalities and early therapy methods for kids who lose their primary teeth too soon because of systemic disorders. Methodology We conducted a retrospective observational study to examine the early loss of primary teeth in children aged 6-10 years with a history of systemic diseases at Naseer Teaching & MMC-General Hospital, Peshawar; Hayatabad Medical Complex, Peshawar; DHQ Teaching Hospital, Kohat; and Fauji Foundation Hospital, Multan from January to December 2022. After carefully gathering data from medical records, a sample of 360 patients meeting the inclusion criteria was examined. SPSS Statistics version 27 (IBM Corp., Armonk, NY) was used for the statistical analysis. Demographic characteristics, clinical manifestations, and management approaches were compiled using descriptive statistics. For categorical data, frequency distributions and percentages were determined, and for continuous variables, means and standard deviations (SD) were calculated. Regression analysis was conducted to analyze relationships between related variables and treatment outcomes. A p-value <0.05 was considered statistically significant. Results The majority of patients were aged between six and eight years, and the cohort had an equal gender distribution. Dental problems including malocclusion (n=175, 48.61%) and early tooth loss (n=245, 68.06%) were common, as were systemic illnesses like genetic disorders (n=45, 12.50%) and endocrine abnormalities (n=67, 18.61%). Diagnostic procedures were often carried out, such as radiographic exams (n=256, 71.11%) and blood tests (n=123, 34.17%). Dietary supplements (n=60, 16.67%) and dental procedures (n=75, 20.83%) constituted the bulk of the treatment. Significant treatment outcomes that demonstrated the efficacy of the therapies were as follows: high patient satisfaction (n=213, 59.17%), improved oral health (n=255, 70.83%), and symptom relief (n=187, 51.94%). Conclusion Our findings highlight the significant impact of certain practical methods for identifying and treating early tooth loss in pediatric patients with systemic illnesses, leading to patient satisfaction in terms of symptom relief and enhanced dental health.

Prenatal exposure to environmental toxins and comprehensive dental findings in a population cohort of children

Environmental toxins are known to have many impacts on growth and development in humans, starting in utero. Alterations in amelogenesis, caused by chemical and physical trauma that occur during the antenatal, perinatal and postnatal time periods, may result in developmental defects in deciduous and permanent tooth enamel, as demonstrated in animal studies. These defects can be clinically visible and result in a variety of morphological and functional problems in the dentition. Since enamel does not remodel after formation, it may serve as a permanent record of insults during organ development.Our primary purpose was to investigate any possible relationship between intrauterine exposure to endocrine disrupting chemicals (phenols and phthalates) and developmental defects in enamel in children, while also accounting for fluoride exposure. Our secondary purpose was to report descriptively on findings from comprehensive dental examinations performed on 356 children that were drawn from the general paediatric population. A cohort of children from the Utah Children's Project (N = 356) that had full medical exams, comprehensive medical and family histories and available biospecimens were given extraoral and intraoral examinations. They also completed an oral health questionnaire. Standardized intraoral photographs were taken of the teeth and viewed by standardised examiners and the dental observations were recorded for a full inventory of findings, including: tooth morphology, caries, restorations, colorations, attrition, erosion, fractures and hypomineralization. Perinatal maternal urine samples were assessed for the concentration of fluoride, phenols and phthalates, including bisphenol A (BPA).Pairwise statistical analyses were done to correlate the dental findings with one another and with the presence of environment chemicals found in the urine samples. Hypomineralization was the most common finding (96% of children; 37% of deciduous teeth, 42% of permanent teeth), consistent with molar incisor hypomineralization (MIH) described in other human populations. No consistent correlations were seen between dental findings and the presence of phenols and phthalates in prenatal urine, but the number of samples available for the assessment was limited (n = 35).In conclusion, we found a high proportion of dental hypomineralization in a population based paediatric cohort, but did not find an association with prenatal exposure to phenols and phthalates.

The Oral Health of a Group of 19th Century South Australian Settlers in Relation to Their General Health and Compared with That of Contemporaneous Samples

The aims of this study are to determine the oral health status of a rare sample of 19th-century migrant settlers to South Australia, how oral conditions may have influenced their general health, and how the oral health of this group compares with contemporaneous samples in Australia, New Zealand, and Britain. Dentitions of 18 adults and 22 subadults were investigated using non-destructive methods (micro-CT, macroscopic, radiographic). Extensive carious lesions were identified in seventeen adults and four subadults, and from this group one subadult and sixteen adults had antemortem tooth loss. Sixteen adults showed evidence of periodontal disease. Enamel hypoplastic (EH) defects were identified in fourteen adults and nine subadults. Many individuals with dental defects also had skeletal signs of comorbidities. South Australian individuals had the same percentage of carious lesions as the British sample (53%), more than other historic Australian samples, but less than a contemporary New Zealand sample. Over 50% of individuals from all the historic cemeteries had EH defects, suggesting systemic health insults during dental development were common during the 19th century. The overall oral health of the South Australian settlers was poor but, in some categories, (tooth wear, periapical abscess, periodontal disease), better than the other historic samples.

Different Dental Manifestations in Sisters with the Same ALPL Gene Mutation: A Report of Two Cases

Hypophosphatasia (HPP) is an inherited disease caused by mutation of the alkaline phosphatase (ALPL) gene in an autosomal dominant or an autosomal recessive manner. The main symptoms of HPP are bone hypomineralization and early exfoliation of the primary teeth. Some of the mutations identified in autosomal dominant families are reported to have dominant negative effects. In addition, the penetrance can vary among patients with the same variant even within the same family, resulting in various phenotypes of systemic symptoms. However, differences in dental symptoms between patients with HPP and carriers with the same ALPL variant have not been reported. Herein, we report on two sisters who had the same heterozygous ALPL variant with dominant negative effects. The older sister had bone and dental symptoms and was diagnosed with childhood HPP. In contrast, the younger sister was a carrier with no bone and dental symptoms. It can be inferred that this phenomenon was caused by the difference in penetrance. This case revealed that carriers with the ALPL mutation may have no dental symptoms characteristic of HPP. Because HPP is sometimes progressive, it is very important to carefully monitor carriers to detect the possible onset of dental and systemic symptoms.

Clinical and Radiographical Evaluation of Non-syndromic Dental Anomalies in Turkish Children

AIM: The aim of this study was to investigate the frequency and distribution of non-syndromic developmental dental anomalies in Turkish children in different age groups. SUBJECTS AND METHODS: A sample of 516 children aged 3–17 years who attended the Pediatric Dentistry Department of Istanbul Aydin University were evaluated clinically and radiographically for the existence of any structural, shape, and number anomalies of the developing dentition, and the most prevalent anomalies were compared according to gender and age groups. RESULTS: The most observed dental anomaly was Molar Incisor Hypomineralization (MIH) and tooth agenesis by a percentage of 14.3% and 4.8%, respectively. The incidence of MIH was higher in 7–8 and 9–10 years of age groups. There were no anomalies detected in 361 (70%) of the patients; meanwhile, only one anomaly was observed in 110 (21.3%), two different anomalies at the same time were observed in 33 (6.4%), and more than two anomalies were observed in 12 (2.3%) in the study group. STATISTICS: The statistical analysis of the results was obtained using the IBM SPSS Statistics 22 (IBM SPSS, Inc USA) program. p < 0.05 was considered to be statistically significant. CONCLUSION: Although there are no known systemic disturbances, at least, one dental anomaly was observed in 21.3% of the children. The most observed anomalies were MIH and tooth agenesis. An increase in the MIH prevalence throughout the world may lead to the suggestion that more investigations should be made on environmental predisposing factors. Besides, there might be common genetic factors and genes (PAX9, AXIN2, MSX1) affecting both tooth development and tumor formation which may be a potential risk marker for future cancer development.

Factors and Mechanisms Involved in Acquired Developmental Defects of Enamel: A Scoping Review

BACKGROUND

Developmental Defects of Enamel (DDE) is a pathology of the teeth that can greatly alter the quality of life of patients (hypersensitivity, esthetic issues, loss of function, etc.). The acquired DDE may occur as a result of a wide range of acquired etiological factors and his prevalence of this pathology may reach up to 89.9%. The main objective of this research was to identify and analyze, in current literature, the factors related to acquired DDE, in order to propose a general theory about the mechanisms involved.

METHODS

The search of the primary literature was conducted until [December 31, 2021]. Our search strategy uses the Pubmed/MEDLINE database and was structured around 3 terms ["Development," "Defect," and "Enamel"]. To be included, references had to be primary studies, written in English. Exclusion criteria were reviews, in vitro, animal, genetic or archeology studies, and studies focused on clinical management of DDE. One hundred and twenty three articles were included in this scoping review: 4 Randomized clinical trials, 1 letter, 5 cases reports, 2 fundamentals studies, and 111 observational studies (33 Cross-sectional studies, 68 Cohort study and 10 Case-control study). The quality of evidence was assessed using the PEDro scale for clinical trials, the Newcastle-Ottawa scale for observational studies, and a published tool to assess the quality of case reports and case series.

RESULTS

A scoping review of the literature identified 114 factors potentially involved in acquired DDE. The most frequently encountered pathologies are those causing a disorder of calcium homeostasis or a perturbation of the ARNT pathway in mother or child. The link between the ARNT pathway and metabolism deficiency in uncertain and needs to be defined. Also, the implication of this mechanism in tissue impairment is still unclear and needs to be explored.

CONCLUSIONS

By identifying and grouping the risk factors cited in the literature, this taxonomy and the hypotheses related to the mechanism allow health practitioners to adopt behaviors that limit the risk of developing aDDE and to set up a prevention of dental pathology. In addition, by reviewing the current literature, this work provides guidance for basic research, clinical studies, and literature searches.

Case Report: Crown Resorption in a Patient With Junctional Epidermolysis Bullosa and Amelogenesis Imperfecta With LAMB3 Gene Mutations

Background: Epidermolysis bullosa (EB) corresponds to a series of conditions characterized by extreme fragility of the skin and/or mucous membranes. Of the four main types of EB, junctional EB (JEB) is the most associated with alterations in the teeth. The purposes of this study were to determine the clinical, histopathological, and ultrastructural characteristics of teeth with amelogenesis imperfecta (AI) in a patient with JEB, and compare them with control teeth, and correlate the findings with the mutations present in the patient.

Case Report: The study was conducted on a 10-year-old patient with JEB carrier of two recessive mutations in the LAMB3 gene and absence of the laminin-332 protein (LM-332), determined by immunofluorescence on a skin biopsy. The patient presents hypoplastic AI with very thin and yellow-brown colored enamel. Extraction of two permanent molars was performed due to pain and soft tissue covering the crown, resembling pulp polyp or hyperplastic gingiva. Light and scanning electron microscopy (SEM) revealed very thin enamel varying from complete absence to 60 μm, absence of normal prismatic structure, and presence of a cross-banding with a laminated appearance. The histopathological study revealed granulation tissue causing external crown resorption.

Conclusion: Although coronary resorption has been reported in patients with syndromic and non-syndromic AI, this is the first clinicopathological report of coronary resorption in partially erupted teeth in patients with JEB with mutations in the LAMB3 gene and hypoplastic AI. In patients with this condition, the presence of partially erupted teeth with soft tissue covering part of the crown, without a periodontal pocket, and with a radiographic image of partial coronal radiolucency should lead to suspicion of external coronary resorption.

Lack of biological mortality bias in the timing of dental formation in contemporary children: Implications for the study of past populations

OBJECTIVES

Biological mortality bias is the idea that individuals who perish (non-survivors) are biologically distinct from those who survive (survivors). If biological mortality bias is large enough, bioarchaeological studies of nonsurvivors (skeletal samples) cannot accurately represent the experiences of the survivors of that population. This effect is particularly problematic for the study of juvenile individuals, as growth is particularly sensitive to environmental insults. In this study, we test whether biological mortality bias exists in one dimension of growth, namely dental development.

MATERIALS AND METHODS

Postmortem computed tomography scans of 206 children aged 12 years and younger at death were collected from two institutions in the United States and Australia. The sample was separated into children dying from natural causes as proxies for non-survivors and from accidental causes as proxies for survivors. Differences in the timing of dental development were assessed using sequential logistic regressions between dental formation stages and residual analysis of dental minus chronological age.

RESULTS

No consistent delay in age of attainment of dental stages was documented between survivors and non-survivors. Delays between survivors and non-survivors in dental relative to chronological age were greatest for infants, and were greater for females than for males.

DISCUSSION

Lack of biological mortality bias in dental development reinforces confidence in juvenile age estimates and therefore in skeletal growth profiles and growth studies. As dental development is known to be less environmentally sensitive than skeletal growth and development, further studies should examine biological mortality bias in long bone length.

Egyptian Propolis-Loaded Nanoparticles as a Root Canal Nanosealer: Sealing Ability and in vivo Biocompatibility

Background

Successful endodontic therapy is mainly governed by the satisfactory sealing ability of the applied root canal sealer. Also, tolerability of root canal structure to accommodate the presence of a sealer participates in the efficiency of the treatment. Hence, this study was aimed to extrapolate our previous one that was concerned with the preparation and evaluation of novel nature-based root canal sealers. Our current work is focused on the evaluation of sealing ability and in vivo biocompatibility.

Materials and Methods

Egyptian propolis was extracted (ProE) and encapsulated in polymeric nanoparticles (ProE-loaded NPs). Two root sealers, PE sealer and PE nanosealer, were fabricated by incorporating ProE and ProE-loaded NPs, respectively. The sealing ability of the developed sealers was tested by a dye extraction method. An in vivo biocompatibility study was conducted using a subcutaneous implantation method for two and four weeks. At the same time, a model sealer (AH Plus®) was subjected to the same procedures to enable accurate and equitable results.

Results

The teeth treated with PE sealer exhibited weak sealing ability which did not differ from that of unfilled teeth. PE nanosealer enhanced the sealing ability similarly to the model sealer with minimal apical microleakage. Studying in vivo biocompatibility indicated the capability of the three tested sealers to induce cell proliferation and tissue healing. However, PE nanosealer had superior biocompatibility, with higher potential for cell regeneration and tissue proliferation.

Conclusion

PE nanosealer can be presented as an innovative root canal sealer, with enhanced sealing ability as well as in vivo biocompatibility. It can be applied as a substitute for the currently available sealers that demonstrate hazardous effects.

Dental Anomalies in Rare, Genetic Ciliopathic Disorder-A Case Report and Review of Literature

Background: Primary ciliary dyskinesia (PCD) is a rare, ciliopathic disorder. In many ciliopathies, dental anomalies are observed alongside other symptoms of the disease. To date, there are no published reports concerning the dental developmental problems that are associated with ciliary defects in PCD patients. Methods: Patients suffering from PCD underwent dental clinical examination, which included the assessment of developmental disorders regarding the number and morphological structure of the teeth (size and shape) as well as developmental disorders of mineralised dental tissues. Then, three-dimensional radiographic examination was performed utilising Cone Beam Computed Tomography (CBCT). Results: Four PCD patients, aged 31-54, agreed to enter the study. Dental examinations showed the presence of dental developmental disorders in three of them. Additionally, CBCT showed abnormalities in those patients. Conclusions: 1. The dental phenotype in PCD patients seems to be heterogeneous. Tooth developmental disorders resulting from abnormal odontogenesis may be a symptom of PCD that is concomitant with other developmental abnormalities resulting from malfunctioning primary cilia. 2. Patients with ciliopathies are likely to develop dental developmental defects. Therefore, beginning in early childhood, they should be included in a targeted specialised dental programme to enable early diagnosis and to ensure dedicated preventive and therapeutic measures.

A Study of Enamel Defects and Dental Caries of Permanent Dentition in School Children with Intellectual Disability

Data concerning the prevalence of developmental enamel defects and their association with dental caries in individuals with intellectual disability are scarce. This paper aims to evaluate the prevalence and distribution of developmental enamel defects and dental caries in the permanent dentition of special-care school children from Poznan (Poland). Out of 1091 students attending all special-care schools in the city, the study covered 268 subjects with intellectual disability (mild, moderate, severe, and profound) with permanent dentition, aged 10-20. One calibrated dentist performed dental examinations. The Statistica Software v10 was used for statistical analysis, assuming the level of statistical significance p ≤ 0.05. Among the subjects of the study, 19.40% presented developmental enamel defects. The number of teeth with changes ranged from 1 to 28, with maxillary incisors most frequently affected. Students without developmental enamel defects had more teeth observed with active caries compared to those with such changes (10.92% vs. 7.82%, p < 0.01). The highest number of students with developmental defects of enamel was observed in the group of individuals with mild intellectual disabilities. The present study revealed that in special-care students from Poznan, enamel defects and dental caries were frequently observed. However, individuals with developmental enamel defects did not show higher dental caries indices.

Clinical Practice Guidelines for Hypophosphatasia

Hypophosphatasia (HPP) is a rare bone disease caused by inactivating mutations in the ALPL gene, which encodes tissue-nonspecific alkaline phosphatase (TNSALP). Patients with HPP have varied clinical manifestations and are classified based on the age of onset and severity. Recently, enzyme replacement therapy using bone-targeted recombinant alkaline phosphatase (ALP) has been developed, leading to improvement in the prognosis of patients with life-threatening HPP. Considering these recent advances, clinical practice guidelines have been generated to provide physicians with guides for standard medical care for HPP and to support their clinical decisions. A task force was convened for this purpose, and twenty-one clinical questions (CQs) were formulated, addressing the issues of clinical manifestations and diagnosis (7 CQs) and those of management and treatment (14 CQs). A systematic literature search was conducted using PubMed/MEDLINE, and evidence-based recommendations were developed. The guidelines have been modified according to the evaluations and suggestions from the Clinical Guideline Committee of The Japanese Society for Pediatric Endocrinology (JSPE) and public comments obtained from the members of the JSPE and a Japanese HPP patient group, and then approved by the Board of Councils of the JSPE. We anticipate that the guidelines will be revised regularly and updated.

Hypophosphatasia: Canadian update on diagnosis and management

Hypophosphatasia (HPP) is a rare inherited disorder of bone and mineral metabolism caused by loss of function mutations in the ALPL gene. The presentation in children and adults can be extremely variable and natural history is poorly understood particularly in adults. Careful patient evaluation is required with consideration of pharmacologic intervention in individuals meeting criteria for therapy.

INTRODUCTION

The purposes of this review are to present current evidence regarding the diagnosis and management of hypophosphatasia in children and adults and provide evidence-based recommendations for management.

METHOD

A MEDLINE, EMBASE, and Cochrane database search and literature review was completed. The following consensus recommendations were developed based on the highest level of evidence as well as expert opinion.

RESULTS

Hypophosphatasia is a rare inherited disorder of bone and mineral metabolism due to loss of function mutations in the tissue non-specific alkaline phosphatase (ALPL) gene causing reductions in the activity of the tissue non-specific isoenzyme of alkaline phosphatase (TNSALP). Deficient levels of alkaline phosphatase result in elevation of inhibitors of mineralization of the skeleton and teeth, principally inorganic pyrophosphate. The impaired skeletal mineralization may result in elevations in serum calcium and phosphate. Clinical features include premature loss of teeth, metatarsal and subtrochanteric fractures as well as fragility fractures. Poor bone healing post fracture has been observed. Myalgias and muscle weakness may also be present. In infancy and childhood, respiratory and neurologic complications can occur.

CONCLUSIONS

HPP is associated with significant morbidity and mortality. Pharmacologic intervention can result in significant clinical improvement. This Canadian position paper provides an overview of the musculoskeletal, renal, dental, respiratory, and neurologic manifestations of hypophosphatasia. The current state of the art in the diagnosis and management of hypophosphatasia is presented.

Oral health in patients with Prader-Willi syndrome: current perspectives

Prader-Willi syndrome (PWS) is a rare complex multisystem disorder and presents several aspects related to dentistry. The purpose of this review is to present current perspectives about oral health in patients with PWS. Delay development, hyperphagia, foamy and highly viscous saliva raise the risk of caries and contribute to tooth wear. Cariogenic foods uncontrolled consumption allows to obesity and dental problems progress worsening systemic disorders. These factors can be controlled. The success in follow-ups with caries free and oral health controlled demonstrate the importance of multidisciplinary team intervention corroborated by support at home from birth to adulthood. Thereby, current perspective on the disease is that there is possibility of proper maintenance of oral health in PWS patients. Guided care interferes positively with the overall well-being and quality of life of the individual with PWS and their family. A multidisciplinary team with a focus on teaching patients and family members will help minimize eventual problems.

Age estimation using pulp/enamel volume ratio of impacted mandibular third molars measured on CBCT images in a northern Chinese population

The present study aims to evaluate the relation between chronological age and the ratio of pulp volume (PV) to enamel volume (EV) of impacted mandibular third molars (IMTMs) by using cone-beam computed tomography (CBCT) images and an improved 3D image segmentation technique. A sample of CBCT images of IMTM was collected from 414 northern Chinese subjects (214 male and 200 female clinical patients) ranging in age from 20 to 65 years. The GrowCut effect image segmentation (GCEIS) module algorithm was used to calculate the PV and EV from CBCT images. The total sample was divided into a training group and validation group in a ratio of 7 to 3. The PV/EV ratio (PEr) in the training sample was used to develop a mathematical formula for age estimation as follows: age = - 5.817-21.726 × Ln PEr (p < 0.0001) (Ln, natural logarithm). The mean absolute error (MAE) and root mean square error (RMSE) were used to determine the precision and accuracy of the mathematical formula in the validation group and all samples. The MAEs in the male, female, and pooled gender samples were 9.223, 7.722, and 8.41, respectively, and the RMSEs in the male, female, and pooled gender samples were 10.76, 9.58, and 9.986, respectively. The precise and accurate results indicate that the PEr of IMTM in CBCT images is a potential index for dental age estimation and is possible to be used in forensic medicine.

Epidemiological Profile of the Pathologies of the Oral Cavity in a Peruvian Population: A 9-Year Retrospective Study of 18,639 Patients

Aim

To determine the epidemiological profile of oral diseases in a marginal urban Peruvian population.

Methods

A 9-year retrospective study was conducted, analysing 18,639 clinical records from the María Auxiliadora Hospital between 2006 and 2015 with diagnoses of oral lesions using ICD-10 criteria. Clinical records were analysed for sex, tumour, periapical abscess and sinus, cysts of the oral region, other lesions of the oral mucosa and cavity, gingivitis and periodontal disease, dentofacial anomalies, diseases of pulp, etc.

Results

Of 18,639 cases, the prevalence was higher in women for the following pathologies: unspecified dental caries (30.6%); impacted tooth in the category of disorders of tooth development and eruption (2.0%); pulpitis (6.8%) in the category of diseases of pulp and periapical tissues; temporomandibular joint (TMJ) disorders (1.5%) in the category of dentofacial anomalies; acute gingivitis (7.5%); radicular cyst (0.3%) in the category of cysts of the oral region; and periapical abscess without sinus (2.0%).

Conclusions

We found a significant association between sex and different types of dental caries, disturbances in tooth eruption, diseases of pulp and periapical tissues, and dentofacial anomalies. The study also shows a statistically significant association between sex and gingivitis, periodontal disease, and periodontal abscess and sinus.

Hypophosphatasia: oral cavity and dental disorders

Dental anomalies exist in every subtype of hypophosphatasia (HPP), from the most severe to the most moderate, called odontohypophosphatasia. The forms are defined by the age at onset of the initial symptoms. These anomalies affect all dental mineralized tissues from enamel, dentin and cementum to alveolar bone in a gradient proportional to the severity of the disease. Early loss of the deciduous teeth, before 3 years of age, and then possibly of the permanent teeth, is due to an abnormality of the cementum, the tissue attaching the teeth to alveolar bone, and is the most frequent abnormality. Tooth loss is a very important diagnostic sign and needs to be recognized. Patients with HPP need specialized oral and dental care in coordination with the reference and expert centers. The oral and dental signs and their treatment remain poorly known. The recording of the abnormalities and their treatment in a registry is indispensable in order to enhance patient management and oral and dental health.

A Novel Fluoride Containing Bioactive Glass Paste is Capable of Re-Mineralizing Early Caries Lesions

White-spot-lesions (WSL) are a common complication associated with orthodontic treatment. In the current study, the remineralization efficacy of a BiominF^® paste was compared to the efficacy of a fluoride gel. Methods: Orthodontic brackets were bonded to 60 human premolars buccal surfaces, which were covered with varnish, except a small treatment area (3 mm²). All specimens were challenged by a demineralization solution for 4 days. Specimens were assigned into 4 groups: BiominF^® paste, Fluoride (4-min application), fluoride (twenty four hours application), and the control (n = 15). After cross-sectioning, enamel slabs having a thickness of approximately 100–120 μm were obtained. A TMR (Transverse Micro Radiography) technique was used to observe the sub-surface enamel lesions’ depth and mineral density, and their response to the remineralization protocols. One way ANOVA was used to analyze the results (α = 0.05). The top and the cross-sectional surfaces were observed using SEM/EDS. Results: Specimens treated with BiominF^® paste showed significant decrease in delta z values, however lesion depth showed no significant difference when compared to the other three groups (p < 0.05). SEM/EDS observation showed the formation of crystal like structures on top of enamel demineralized surfaces, when treated with BiominF^® paste. In conclusion BiominF^® paste can be considered an effective remineralizing agent for white spot Lesions.

Interrelationships Between Morphometric, Densitometric, and Mechanical Properties of Teeth in 5-Month-Old Polish Merino Sheep

Interrelationships between morphological, densitometric, and mechanical properties of deciduous mandibular teeth (incisors, canine, second premolar) were investigated. To perform morphometric, densitometric, and mechanical analyses, teeth were obtained from 5-month-old sheep. Measurements of mean volumetric tooth mineral density and total tooth volume were performed using quantitative computed tomography. Microcomputed tomography was used to measure total enamel volume, volumetric enamel mineral density, total dentin volume, and volumetric dentin mineral density. Maximum elastic strength and ultimate force of teeth were determined using 3-point bending and compression tests. Pearson correlation coefficients were determined between all investigated variables. Mutual dependence was observed between morphological and mechanical properties of the investigated teeth. The highest number of positive correlations of the investigated parameters was stated in first incisor indicating its superior predictive value of tooth quality and masticatory organ function in sheep. Positive correlations of the volumetric dentin mineral density in second premolar with final body weight may indicate predictive value of this parameter in relation with growth rate in sheep. Evaluation of deciduous tooth properties may prove helpful for breeding selection and further reproduction of sheep possessing favorable traits of teeth and better masticatory organ function, leading to improved performance and economic efficiency of the flock.

Multiplex epithelium dysfunction due to CLDN10 mutation: the HELIX syndrome

PurposeWe aimed to identify the genetic cause to a clinical syndrome encompassing hypohidrosis, electrolyte imbalance, lacrimal gland dysfunction, ichthyosis, and xerostomia (HELIX syndrome), and to comprehensively delineate the phenotype.MethodsWe performed homozygosity mapping, whole-genome sequencing, gene sequencing, expression studies, functional tests, protein bioinformatics, and histological characterization in two unrelated families with HELIX syndrome.ResultsWe identified biallelic missense mutations (c.386C>T, p.S131L and c.2T>C, p.M1T) in CLDN10B in six patients from two unrelated families. CLDN10B encodes Claudin-10b, an integral tight junction (TJ) membrane-spanning protein expressed in the kidney, skin, and salivary glands. All patients had hypohidrosis, renal loss of NaCl with secondary hyperaldosteronism and hypokalemia, as well as hypolacrymia, ichthyosis, xerostomia, and severe enamel wear. Functional testing revealed that patients had a decreased NaCl absorption in the thick ascending limb of the loop of Henle and a severely decreased secretion of saliva. Both mutations resulted in reduced or absent Claudin-10 at the plasma membrane of epithelial cells.ConclusionCLDN10 mutations cause a dysfunction in TJs in several tissues and, subsequently, abnormalities in renal ion transport, ectodermal gland homeostasis, and epidermal integrity.

Molar incisor hypomineralization in HIV-infected children and adolescents

The objective was to determine the prevalence of molar incisor hypomineralization (MIH) among individuals between 7 and 15 years old infected or noninfected with human immunodeficiency virus (HIV). The study was conducted with 33 HIV-infected individuals (study group; SG) and 66 non-HIV-infected schoolchildren (control group; CG), paired by gender and age. Data collection was based on medical records (SG), a questionnaire for caregivers and oral examination for diagnosis of MIH (European Academy of Pediatric Dentistry criteria) and caries (DMFT index and ICDAS). Data were analyzed with Mann-Whitney, chi-square, and Fisher's exact tests and logistic regression. In SG, MIH (45.5%) and caries (87.9%) had higher prevalence. MIH was associated with use of protease inhibitors in SG (OR: 2.14; 95% CI: 1.21 to 3.77) and incubator need in CG (OR: 2.80; 95% CI: 1.71 to 9.10). HIV-infected patients had a higher prevalence of MIH and dental caries in the permanent dentition.

Clinical Comparative Study of the Effects of Helicobacter Pylori Colonization on Oral Health in Children

OBJECTIVE

To isolate Helicobacter pylori (HP) from the dental plaque of a selected group of children and to compare the oral and salivary findings of patients with those of a healthy control group.

METHODS

A total of 70 children aged 5-15 years were included in this study. An intraoral examination was performed for each patient, and dental plaque and saliva specimens were collected for analysis. Oral health conditions, nutritional habits, tooth brushing frequency, saliva pH levels, flow velocity, and buffering capacities were noted. The Kruskal-Wallis test was used for comparison of the DMFT and dft index. The significance level was set at p=0.05.

RESULTS

The prevalence of HP in dental plaque was higher in study group than controls (p<0.05). There were no significant differences between groups with respect to DMFT and dft scores, nutritional habits, tooth brushing frequency, saliva pH level or flow velocity (p>0.05). Meanwhile, the buffering capacity of saliva was lower in HP gastritis patients (p<0.05).

CONCLUSION

There was a high prevalence of HP in dental plaque; thus, the oral cavity may be an important reservoir for HP. Good oral hygiene could be a positive contributor to the treatment of gastritis.

Dental enamel development defects in children and adolescents with HIV infection: case-control study

To determine the frequency of Enamel Development Defects (DDE) and associated factors in children and adolescents infected with HIV. A case-control study was conducted in HIV-infected patients (n = 52), aged 3 to 15, and a control group formed by preschool and schoolchildren (n = 104) matched according to gender, age and household income. Data on medical history, neonatal and maternal conditions were obtained. For diagnosis of enamel defects was used modified DDE Index. DDE frequency was 61.5% in the case group and 58.7% in the control group (p = 0.569). Infection of the genitourinary tract and maternal hemorrhage were factors associated with DDE in the case and control groups, respectively. An association was observed between the use of antiretroviral regimens with protease inhibitors or efavirenz and DDE in the permanent dentition. Children and adolescents HIV-infected showed a DDE frequency similar to healthy patients, but factors associated with this condition were different between the groups.

Age estimation based on pulp cavity/chamber volume of 13 types of tooth from cone beam computed tomography images

AIM

The aims of this study are to identify which type of tooth has the strong relationship between age and pulp cavity/chamber volume among 13 types of tooth from the same dentition and to determine whether the inclusion of multiple types of tooth may improve the accuracy of age estimation.

MATERIALS AND METHODS

Cone beam computed tomography (CBCT) images from 115 females and 125 males aged between 16 and 63 years were analyzed. The DICOM data of all the images were imported into ITK-SNAP 2.4 for the calculation of pulp cavity/chamber volumes. Logarithmic regression analysis and multiple linear regression analysis were applied to establish the relationship between age and pulp cavity/chamber volumes.

RESULTS

Among the 13 types of tooth, maxillary second molars have the largest R (2) (0.491, 0.642, and 0.498) and the smallest SEE (8.119, 6.754, and 8.022) in male, female, and pooled gender samples, respectively. The multiple linear regression analysis for the combination of multi-types of tooth indicated that a larger R (2) (0.627, 0.701, and 0.631) and smaller SEE (7.100, 6.258, and 6.970) than the counterpart calculated from the logarithmic regression analysis of a single type of tooth in male, female, and pooled gender samples, respectively.

CONCLUSION

The pulp chamber volume of the maxillary second molars has the largest correlation coefficient with age. Using multiple types of tooth may improve the accuracy of age estimation compared with only one type of tooth used.

Distinguishing between enamel fluorosis and other enamel defects in permanent teeth of children

Background. The inconsistent prevalence of fluorosis for a given level of fluoride in drinking water suggests developmental defects of enamel (DDEs) other than fluorosis were being misdiagnosed as fluorosis. The imprecise definition and subjective perception of fluorosis indices could result in misdiagnosis of dental fluorosis. This study was conducted to distinguish genuine fluorosis from fluorosis-resembling defects that could have adverse health-related events as a cause using Early Childhood Events Life-grid method (ECEL).

Methods. A study was conducted on 400 9-year-old children from areas with high, optimal and low levels of fluoride in the drinking water of Fars province, Iran. Fluorosis cases were diagnosed on the standardized one view photographs of the anterior teeth using Dean’s and TF (Thylstrup and Fejerskov) Indices by calibrated dentists. Agreements between examiners were tested. Early childhood health-related data collected retrospectively by ECEL method were matched with the position of enamel defects.

Results. Using both Dean and TF indices three out of four dentists diagnosed that 31.3% (115) children had fluorosis, 58.0%, 29.1%, and 10.0% in high (2.12–2.85 ppm), optimal (0.62–1.22 ppm), and low (0.24–0.29 ppm) fluoride areas respectively (p < 0.001). After matching health-related events in the 115 (31.3%) of children diagnosed with fluorosis, 31 (8.4%) of children had fluorosis which could be matched with their adverse health-related events. This suggests that what was diagnosed as fluorosis were non-fluoride related DDEs that resemble fluorosis.

Discussion. The frequently used measures of fluorosis appear to overscore fluorosis. Use of ECEL method to consider health related events relevant to DDEs could help to differentiate between genuine fluorosis and fluorosis-resembling defects.

Hypophosphatasia: an overview of the disease and its treatment

This review presents the current knowledge on hypophosphatasia, a rare genetic disease of very variable severity (from lethal to mild) and clinical presentation, caused by defective production of tissue-non-specific alkaline phosphatase (TNSALP). Hypophosphatasia can affect babies in utero as well as infants, children, and adults. The article first presents the genetics of TNSALP and its many known mutations underlying the disease. Then, it presents the epidemiology, classification, and clinical presentation of the six different forms of the disease (perinatal lethal, prenatal benign, infantile, childhood, adult, and odontohypophosphatasia) as well as the essential diagnostic clues. The last section on treatment presents a survey of the therapeutic approaches, up to the ongoing phase 2 studies of enzyme replacement therapy.

Age estimation based on pulp chamber volume of first molars from cone-beam computed tomography images

AIM

To establish a method that can be used for human age estimation on the basis of pulp chamber volume of first molars and to identify whether the method is good enough for age estimation in real human cases.

MATERIALS AND METHODS

CBCT images of 373 maxillary first molars and 372 mandibular first molars were collected to establish the mathematical model from 190 female and 213 male patients whose age between 12 and 69 years old. The inclusion criteria of the first molars were: no caries, no excessive tooth wear, no dental restorations, no artifacts due to metal restorative materials present in adjacent teeth, and no pulpal calcification. All the CBCT images were acquired with a CBCT unit NewTom VG (Quantitative Radiology, Verona, Italy) and reconstructed with a voxel-size of 0.15mm. The images were subsequently exported as DICOM data sets and imported into an open source 3D image semi-automatic segmenting and voxel-counting software ITK-SNAP 2.4 for the calculation of pulp chamber volumes. A logarithmic regression analysis was conducted with age as dependent variable and pulp chamber volume as independent variables to establish a mathematical model for the human age estimation. To identify the precision and accuracy of the model for human age estimation, another 104 maxillary first molars and 103 mandibular first molars from 55 female and 57 male patients whose age between 12 and 67 years old were collected, too. Mean absolute error and root mean square error between the actual age and estimated age were used to determine the precision and accuracy of the mathematical model. The study was approved by the Institutional Review Board of Peking University School and Hospital of Stomatology.

RESULTS

A mathematical model was suggested for: AGE=117.691-26.442×ln (pulp chamber volume). The regression was statistically significant (p=0.000<0.01). The coefficient of determination (R(2)) was 0.564. There is a mean absolute error of 8.122 and root mean square error of 5.603 between the actual age and estimated age for all the tested teeth.

CONCLUSION

The pulp chamber volume of first molar is a useful index for the estimation of human age with reasonable precision and accuracy.

Caries in adolescents in relation to their skeletal status

OBJECTIVE

Despite well-known evidence of association of caries with bone metabolic diseases, there are only a small number of studies about caries and bone mineral density (BMD) on pediatric population. We evaluated the possibility of bone mineralization and metabolism disturbances in children with caries and compared them with healthy individuals.

MATERIALS AND METHODS

A total of 123 patients with caries (63 boys and 60 girls), aged 12-15 years, were included. The children were divided according caries stage: the decayed, missing, and filled tooth (DMFT) group (n=73) and the initial caries (IC) group (n=50), which have clinically active initial caries lesions on the enamel ("white spots"). Caries-free (CF) children (n=42) were the healthy controls. Bone mineralization was measured in all children with caries and healthy controls by dual-energy X-ray absorptiometry of the lumbar spine (L1-L4). For the assessment of bone metabolism, osteocalcin, carboxy terminal telopeptide of type I collagen (CTX), parathyroid hormone, Ca²⁺, inorganic phosphate, and total alkaline phosphatase were used.

RESULTS

Children with DMFT have low BMD and BMD Z score in association with low osteocalcin and high CTX levels, compared with IC (p=0.008 and p=0.0001, respectively) and CF children (p<0.0000 and p=0.0001, respectively). In DMFT, Ca²⁺ was significantly higher compared with IC (p=0.01) and CF (p=0.003). Caries stages negatively correlated with BMD (r=-0.86, p<0.001). A differently directed correlation between CTX and osteocalcin was detected: CTX was negatively related to osteocalcin in the DMFT group (r=-0.22, p=0.043) and positively related in the IC (r=0.42, p=0.002) and CF children (r=0.58, p=0.0000).

CONCLUSIONS

Children with any caries stage have decreased BMD accompanied with increased bone resorption. We consider that caries could be a marker of impact bone mineralization and metabolism.

Er:YAG Laser Dental Treatment of Patients Affected by Epidermolysis Bullosa

Aim. The purpose of this study was to evaluate the efficacy of Er:YAG laser used for treating hard dental tissue in patients with epidermolysis bullosa (EB). Methods. We report two cases of EB in which an Er:YAG laser was used for conservative treatments. In the first case, the Er:YAG laser (2,940 μm, 265 mJ, 25 Hz) was used to treat caries on a deciduous maxillary canine in an 8-year-old male patient affected by dystrophic EB. In the second case, we treated a 26-year-old female patient, affected by junctional EB, with generalized enamel hypoplasia, and an Er:YAG laser (2,940 μm, 265 mJ, 25 Hz) was used to remove the damaged enamel on maxillary incisors. Results. The use of the Er:YAG laser, with the appropriate energy, was effective in the selective removal of carious tissue and enamel hypoplasia. During dental treatment with the Er:YAG laser, patients required only a few interruptions due to the absence of pain, vibration, and noise. Conclusions. Laser treatment of hard dental tissues is a valuable choice for patients affected by EB since it is less invasive compared to conventional treatment, resulting in improved patient compliance.

Deciduous teeth structure changes in congenital heart disease: Ultrastructure and microanalysis

OBJECTIVES

Oral manifestations recorded for congenital heart disease (CHD) patients include teeth hypoplasia and high caries incidence. These observations suggested that the enamel and dentin of the teeth may be altered, increasing the risk for caries incidence. This study was designed to investigate the effect of CHD on the ultrastructure and composition of deciduous sound teeth.

METHODS

Thirty sound exfoliated human deciduous incisor teeth were selected for this study. They were divided into three groups, Group I (control) from healthy children (n = 6), Group II from acyanotic CHD children (n = 12) and Group III from cyanotic CHD children (n = 12). Each tooth was longitudinally sectioned, providing enough specimens for ultrastructure and chemical analysis using ESEM/EDAX. The results of ESEM/EDAX and dentin image analysis were statistically analyzed using one-way ANOVA test followed by Tukey's test.

RESULTS

Enamel of groups II and III showed increased dissolution and irregular orientation of enamel prisms. Orifices of dentinal tubules demonstrated widening and irregular outlines, also lateral branching increased markedly. Image analysis of dentin ESEM photomicrographs showed a highly significant increase in surface area of dentinal tubules. Decrease in calcium (Ca) and phosphorus (P) levels was statistically significant (P < 0.05).

CONCLUSION

CHDs affect the structure and chemical composition of deciduous teeth.

Morphological alterations in the dentition of type I diabetes mellitus patients

Introduction:

Type 1 diabetes mellitus (DM) is an endocrine disorder that occurs commonly in an age group, where the development of primary and permanent dentition takes place. As altered endocrine functions may affect the shape and size of teeth leading to dental anomalies, this study was conducted to look for the occurrence of any dental anomalies in type I DM patients.

Materials and Methods:

A diabetic camp was conducted at Alur Chandrashekharappa Memorial Hospital, Davangere, where 30 diabetic patients were examined and the impressions of their maxillary and mandibular arches were recorded. Age and sex matched controls were selected randomly, and similar recordings were done.

Results:

Type I diabetic patients showed statistically significant (P < 0.001) morphological alterations of total number of cusps, including presence of 6^th cusp in mandibular molars and extra cusps in mandibular premolars. Other alterations such as microdontia, flower shaped mandibular molars, prominent cusp of carabelli, and oblique ridge in maxillary molars were also noted. Severe attrition was found in 11 (36.6%) of the diabetic patients, whereas the control group showed attrition only in 2 (6.8%) patients.

Conclusion:

Remarkable morphological alterations do occur in the dentition of type I DM patients.

Dental complications of rickets in early childhood: case report on 2 young girls

Vitamin D is an essential hormone for calcium gut absorption. It is also involved in child growth, cancer prevention, immune system responses, and tooth formation. Due to inadequate vitamin D intake and/or decreased sunlight exposure, vitamin D deficiency has resurfaced in developed countries despite known inexpensive and effective preventive methods. Vitamin D deficiency is a common cause of rickets, a condition that affects bone development in children and that can have serious dental complications. Deficiency during pregnancy can cause enamel hypoplasia of primary teeth. Enamel regeneration is currently impossible; hypoplasia is therefore irreversible, and once affected, teeth are prone to fast caries development. Deficiency during early childhood can affect permanent teeth and ensuing caries can sometimes lead to tooth loss at a young age. Oral manifestations of rickets should be diagnosed early by both physicians and dentists to prevent severe dental complications. This case study presents 2 young girls with rickets in early childhood who suffered from subsequent serious tooth decay.

Related factors of dental caries and molar incisor hypomineralisation in a group of children with cystic fibrosis

AIM

To investigate dental caries and molar incisor hypomineralisation (MIH)-related factors such as treatment, diet, brushing and salivary factors in children with cystic fibrosis (CF) compared with healthy peers.

STUDY DESIGN

A cohort study was performed.

METHODS

This study was performed on 30 CF children comprising patients at the Faculty of Medicine and 30 control children recruited from the Dental School. Salivary factors, dental caries, MIH, daily diet, brushing habits were analysed. Statistical analysis was calculated by SPSS for Windows.

RESULTS

Decay missing filled teeth (DMF-T) score was 4.6 ± 4.0 in CF and 7.7 ± 2.7 in control (p = 0.001). 43% of CF children with MIH were found to use antibiotics, but no significant difference in the caries experience was found with antibiotic usage (p > 0.05). DMF-T of CF adolescents (23%) who use Tobramycin was 7 ± 3.5. DMF-T of CF children (20%) who take other antibiotics was 2.5 ± 3.5, but no statistical difference was found (p = 0.054). Saliva pH, salivary flow rate, and buffering capacity were not found statistically significant (p > 0.05).

STATISTICS

Percentage arithmetic mean value, standard deviation, independent sample t test, Fisher's exact test, Chi-square test and Mann-Whitney U test were used, while a p value of <0.05 was considered statistically significant.

CONCLUSIONS

Medication and diet could be considered as a risk factor for dental caries and factors such as salivary pH, good oral hygiene could play a protective role for oral health CF children. MIH frequency and lower caries experience seen in CF children could be due to salivary factors or pharmacological treatment they take. The multidisciplinary approach team would be advantageous in the management of children with CF and oral health should be under control during early years of life by paediatric dentists.

An in vivo investigation of salivary properties, enamel hypomineralisation, and carious lesion severity in a group of Iraqi schoolchildren

BACKGROUND

Hypomineralised enamel is a prevalent, congenital defect vulnerable to deteriorate post-eruptively particularly in the presence of an unfavourable oral environment.

AIMS

To assess the influence of salivary characteristics on the clinical presentation of hypomineralisation lesions diagnosed in first permanent and second primary molars and to evaluate caries severity in relation to the defect's clinical presentation.

DESIGN

Recruitment consisted of 445 seven- to nine-year-old participants, of whom 152 were diagnosed as having molar hypomineralisation (MH); the remaining unaffected subjects (N = 293) were considered their controls for saliva analysis. Dental caries status was assessed in 300 subjects of saliva sub-sample, equally divided as MH-affected and non-affected children. The International Caries Detection and Assessment System was used for caries detection. Salivary flow rates, viscosity, pH, and buffering capacity were determined.

RESULTS

Molar hypomineralisation-affected children have significantly higher mean caries scores compared to the non-affected group. Dentinal carious lesions were ten times more frequent in teeth with post-eruptive breakdown (PEB) than with teeth with opacities only. Low salivary flow rates (LSFR), moderately viscous saliva, and low pH were significantly more common in the affected group. LSFR and moderate and highly acidic saliva were more likely associated with PEB.

CONCLUSION

Demarcated hypomineralised enamel is a dynamic defect highly influenced by individual characteristics of the oral environment.

Hereditary dentine diseases resulting from mutations in DSPP gene

OBJECTIVES

This review groups the newest results of molecular analyses of DSPP gene for patients diagnosed either with dentinogenesis imperfecta type II/III or dentine dysplasia and tries to link the phenotypes with specific mutations in the DSPP gene.

DATA

The review includes biochemical data introducing a specificity of DSPP protein which justifies it as a critical factor for dentine mineralization and maturation. The majority of the review analyzes mutations in the DSPP gene which result in phenotypes of dentinogenesis imperfecta types II or/and III or dentine dysplasia.

SOURCES

An electronic search was conducted in the databases of Pub Med and supplemented by manual study of relevant references.

STUDY SELECTION

52 out of 108 references were finally selected for the review based on the novelty and/or originality of data.

CONCLUSION

Hereditary dentine disorders dentinogenesis imperfecta type II/III and dentine dysplasia are currently proposed to be one disease with distinct clinical manifestations reflecting various mutations in the same DSPP gene. For years both disorders were linked exclusively to mutations in the DSP code but a growing number of papers describe mutations which manifest a similar phenotype but are localized in the strongly repetitive sequence of the 3' terminus of the DSPP which codes DPP protein. Our search suggests that the localization of mutation in the sequence of the DSPP gene might result in a different phenotype due to the diverse cellular fate of the mutated protein. Thus comprehensive research on the cellular fate and processing of both normal and mutated DSPP is still required.

Requirements for ion and solute transport, and pH regulation during enamel maturation

Transcellular bicarbonate transport is suspected to be an important pathway used by ameloblasts to regulate extracellular pH and support crystal growth during enamel maturation. Proteins that play a role in amelogenesis include members of the ABC transporters (SLC gene family and CFTR). A number of carbonic anhydrases (CAs) have also been identified. The defined functions of these genes are likely interlinked during enamel mineralization. The purpose of this study is to quantify relative mRNA levels of individual SLC, Cftr, and CAs in enamel cells obtained from secretory and maturation stages on rat incisors. We also present novel data on the enamel phenotypes for two animal models, a mutant porcine (CFTR-ΔF508) and the NBCe1-null mouse. Our data show that two SLCs (AE2 and NBCe1), Cftr, and Car2, Car3, Car6, and Car12 are all significantly up-regulated at the onset of the maturation stage of amelogenesis when compared to the secretory stage. The remaining SLCs and CA gene transcripts showed negligible expression or no significant change in expression from secretory to maturation stages. The enamel of CFTR-ΔF508 adult pigs was hypomineralized and showed abnormal crystal growth. NBCe1-null mice enamel was structurally defective and had a marked decrease in mineral content relative to wild-type. These data demonstrate the importance of many non-matrix proteins to amelogenesis and that the expression levels of multiple genes regulating extracellular pH are modulated during enamel maturation in response to an increased need for pH buffering during hydroxyapatite crystal growth.

Enamel pathology resulting from loss of function in the cystic fibrosis transmembrane conductance regulator in a porcine animal model

Cystic fibrosis (CF) is caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR), a phosphorylation- and ATP-regulated anion channel. CFTR expression and activity is frequently associated with an anion exchanger (AE) such as AE2 coded by the Slc4a2 gene. Mice null for Cftr and mice null for Slc4a2 have enamel defects, and there are some case reports of enamel anomalies in patients with CF. In this study we demonstrate that both Cftr and AE2 expression increased significantly during the rat enamel maturation stage versus the earlier secretory stage (5.6- and 2.9-fold, respectively). These qPCR data im- ply that there is a greater demand for Cl(-) and bicarbonate (HCO₃⁻) transport during the maturation stage of enamel formation, and that this is, at least in part, provided by changes in Cftr and AE2 expression. In addition, the enamel phenotypes of 2 porcine models of CF, CFTR-null, and CFTR-ΔF508 have been examined using backscattered electron microscopy in a scanning electron microscope. The enamel of newborn CFTR-null and CFTR-ΔF508 animals is hypomineralized. Together, these data provide a molecular basis for interpreting enamel disease associated with disruptions to CFTR and AE2 expression.