Enamel hypoplasia is an exclusive ectodermal disturbance, related to alterations in the organic enamel matrix which can cause white flecks, narrow horizontal bands, lines of pits, grooves, and discoloration of the teeth. It can result in compromised oral health that causes physiological and psychological disturbances. Management of enamel hypoplasia not only includes esthetic and functional rehabilitation of the patient but also requires a positive rapport building with the patient due to psychosocial issues. The present case reports elucidate step-by-step management of 16-year-old female patient who presented with localized enamel hypoplasia with severely decayed anterior teeth, poor dental esthetics, and oligodontia of the lower teeth.

Enamel hypoplasia (EH) is a qualitative defect, and it can have a significant impact on oral health. The aim of this study was to evaluate the prevalence of enamel hypoplasia in urban area in Albania.
METHODS: In total, 234 children of both sexes aged 8-12 years old were randomly selected in five schools in Tirana, Albania. They underwent an intra-oral examination. Diagnostic criteria were in accordance with a European meeting on MIH held in Athens, 2003, and the FDI. Medical history was retrieved using questionnaires, and data obtained from clinical examination were recorded.
RESULTS: The prevalence of enamel hypoplasia was 12.8%. The most commonly occurring enamel hypoplasia was the mild type (58.62%). The mandibular first molar showed the highest prevalence of enamel hypoplasia (19.5%), and the maxillary canines and premolars were the least affected (2.3%). In this study, medical story did not have a significant effect on enamel hypoplasia.
CONCLUSIONS: The prevalence of enamel hypoplasia remains high at 12.8%. Interestingly, the features of enamel hypoplasia were consistent across both sexes, with no correlation found between them. The predominant occurrence of mild enamel hypoplasia underscores the importance of implementing oral hygiene strategies in schools to mitigate its progression.

OBJECTIVE: Dental fluorosis is a developmental disturbance of dental enamels, caused by successive exposures to high concentrations of fluoride during odontogenesis, leading to enamels with lower mineral content and increased porosity. The objective of the present study was to assess the prevalence and severity of developmental defects and their relationship to fluoride levels in drinking water.  Methods: Ten villages were selected from Fazilka district, Punjab, India. A total of 1000 (519 males, 481 females) school children aged 12-15 years formed the study population. Eutech ION 2700 (Thermo Fisher Scientific, Waltham, Massachusetts, United States) was used for the estimation of fluoride levels in water. Developmental defects were screened and assessed using the modified Developmental Defects of Enamel (DDE) Index. Statistical evaluation was done using Karl Pearson\'s coefficient of correlation and the Chi-square test with IBM SPSS Statistics for Windows, Version 23, (Released 2015; IBM Corp., Armonk, New York, United States).
RESULTS: The fluoride concentration in drinking water ranged from 0.5 to 2.0 ppm. The prevalence of developmental defects among the study population was 73.4% (range 59% to 100%). The most commonly observed type of defect was diffuse opacity (score 4) in 22.8% of the children. The premolars were the most commonly affected teeth. There was a significant positive correlation between the type (r=0.95; p<0.001) and extent (r=0.82; p<0.001) of developmental defects to the fluoride levels in drinking water.  Conclusion: The drinking water from about 50% of the villages had fluoride levels of 1 ppm or >1 ppm. A significant positive correlation between the severity of enamel defects and increased fluoride levels in water was deciphered. Thus, a simple, effective, and inexpensive method of de-fluoridation of drinking water should be prioritized if alternative sources of drinking water are not made available.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), also known as autoimmune polyglandular syndrome type 1 (APS-1), is a rare genetic disorder caused most often by biallelic mutations in the AIRE gene. Classic clinical findings of the disease are chronic mucocutaneous candidiasis and autoimmunity that primarily targets endocrine tissues, such as hypoparathyroidism and adrenal insufficiency. Recently, however, it has been appreciated that enamel hypoplasia, together with intestinal malabsorption and a characteristic APECED rash, is a prominent early disease manifestation of APECED which can aid in the diagnosis of disease before other potentially life-threatening disease manifestations occur. To demonstrate this point, we present data from a cohort of APECED patients, approximately 70% of who present with enamel dysplasia at an early age. Importantly, early life presentation with enamel dysplasia was predictive of likelihood of development of a subsequent APECED diagnosis. Furthermore, we present a case of a patient with APECED and severe enamel defects and discuss the utility of medical-dental professional co-operation in the diagnosis and management of this complex disorder.

The causes of enamel discoloration can vary, leading to aesthetic concerns for patients. Injuries to primary teeth can lead to developmental issues in permanent successors, with enamel hypoplasia, commonly referred to as Turner\'s tooth. Diverse methods are available for addressing tooth discoloration. A case of an 11-year-old pediatric patient with a brown patch on the upper left central incisor was reported to the Pediatric Dentistry Department. A well-demarcated, yellowish-brown lesion was present on the labial surface of 21 and was diagnosed as Turner\'s hypoplasia. Resin infiltration was done using the Icon Smooth Surface (DMG America Company, Englewood, NJ) resin infiltration kit. The resin infiltration technique provides an approach to meet aesthetic requirements. In this case, the resin infiltration technique was successfully utilized to address the discoloration of the left maxillary central incisor, which was affected by Turner\'s hypoplasia.

OBJECTIVE: This study aimed to identify a DLX3 gene mutation in a family with atypical clinical manifestations of tricho-dento-osseous syndrome (TDO) and its impact on tooth enamel thickness, microhardness, structure and formation.
METHODS: Whole-exome sequencing detected DLX3 mutations in the family. Micro-CT, Vickers hardness tester, energy dispersive spectrometer and scanning electron microscopy were performed on the deciduous teeth of the proband and controls. In vitro experiments preliminarily verified the effect of this mutation on ameloblast differentiation and suggested possible molecular mechanisms.
RESULTS: We found a new DLX3 frame-shift mutation (NM_005220.3: c.604_605del: p. S202 *) in this family. Compared with control teeth, the mutant enamel showed a significant decrease in thickness, hardness and calcium content and an increase in magnesium content. The enamel structure appeared disordered. In an immortalized ameloblast-lineage cell (ALC) line, this mutation affected ameloblast differentiation and downregulated the expression levels of enamel matrix protein (EMP) genes (Amelx, Tuft1, Klk4, Ambn, Odam). A luciferase reporter assay demonstrated that this mutation significantly reduced the transactivation activity of DLX3 on Amelx/Odam/Klk4.
CONCLUSIONS: We found a new DLX3 mutation in a Chinese family with enamel dysplasia and that this mutation may affect ameloblast differentiation by inhibiting the transcriptional activity of Amelx/Odam/Klk4, thereby interfering with enamel formation. Our findings further expand the variation spectrum and enrich the evidence of molecular genetics of DLX3 mutations.

BACKGROUND: Metabolic bone disease causes significant morbidity and mortality, especially when misdiagnosed. With genetic testing, multiple disease pathologies can be analyzed.
METHODS: A 5-year and 9-month-old otherwise healthy Yemeni girl presented to her Yemen physician for evaluation of inward bending of her right knee and short stature. After extensive medical testing, she was given a diagnosis of hypophosphatemic rickets and growth hormone deficiency and started on treatment. Despite appropriate treatment, however, her condition continued to progress, prompting her family to pursue additional workup including genetic testing outside of Yemen. Genetic testing ultimately revealed a variation of unknown significance associated with amelogenesis imperfecta.
CONCLUSIONS: Hypophosphatemic rickets secondary to renal tubular acidosis was the working diagnosis. However, the patient\'s condition did not improve. Further genetic testing revealed a variation of unknown significance associated with amelogenesis imperfecta. We aim to present this case, provide an overview of the causes, and diagnostic metabolic bone health evaluation.

Dental trauma in primary teeth can cause irreversible changes in the development of permanent tooth germs, including enamel hypoplasia, crown dilaceration, and root dilaceration. This article discusses multidisciplinary treatment of enamel hypoplasia and root dilaceration in the maxillary left central incisor of an 11-year-old girl. A 10-year follow-up is reported to demonstrate the long-term clinical outcomes. At the initial presentation, the patient\'s mother reported that the child had an accident at the age of 2 years, resulting in intrusive luxation of the primary maxillary left central incisor. After the accident, the patient was monitored for eruption of the permanent successor tooth, and different approaches were proposed during each period of the patient\'s development on the basis of the clinical diagnosis of root dilaceration and enamel hypoplasia. The crown was restored with composite resin, and the root defect was restored with resin-modified glass ionomer cement. After 10 years, the clinical outcomes highlight that the multidisciplinary approach was successful in preserving the natural tooth with good periodontal health conditions.

Many geographical areas of the world are polluted by both fluoride and sulfur dioxide (SO2). However, the effects of simultaneous exposure to fluoride and SO2 on teeth are unknown. Fibroblast growth factor-9 (FGF9) and transforming growth factor-β1 (TGF-β1) are key signaling molecules in enamel development. The purpose of the study was to explore the effects of co-exposure to fluoride and sulfur dioxide on enamel and to investigate the role and mechanism of FGF9 and TGF-β1. First, sodium fluoride (NaF) and SO2 derivatives were used to construct rat models and evaluate the enamel development of rats. Then, TGF-β1 (cytokine) treatment, SIS3 (inhibitor) treatment and FGF9 gene knockdown were used to explore the mechanism of enamel damage in vitro. The results showed that enamel column crystals in the exposed group were characterized by enamel hypoplasia, as indicated by alterations such as disarrangement of enamel column crystals, space widening and breakage. Ameloblasts also showed pathological changes such as ribosome loss, mitochondrial swelling, nuclear fragmentation and chromatin aggregation. The protein expression of FGF9 was higher and the protein expression of AMBN, TGF-β1 and p-Smad2/3 protein was lower in the groups treated with fluoride and SO2 individually or in combination compared with the control group. Further studies showed that TGF-β1 significantly upregulated p-Smad2/3 and AMBN protein expression and reduced the inhibitory effects of fluoride and SO2; furthermore, SISI blocked the effect of TGF-β1. In addition, knockdown of FGF9 upregulated TGF-β1 protein expression, further activated Smad2/3 phosphorylation, eliminated the inhibitory effects of fluoride and SO2, and increased the protein expression of AMBN. In brief, the study confirms that co-exposure to fluoride and SO2 can result in enamel hypoplasia in rats and indicates that the underlying mechanism may be closely related to the effect of FGF9 on enamel matrix protein secretion through inhibition of the TGF-β1/Smad signaling pathway.

Nablus mask-like facial syndrome (NMLFS) (OMIM: 608156) is an extremely rare genetic syndrome first reported by Ahmad Teebi in 2000. Although it is a rare condition, it is characterized by distinctive facial features such as, expressionless facial appearance, tight, glistening facial skin, low anterior hairline, sparse eyebrows, small palpebral fissures (blepharophimosis), hypertolerism, bulbous nose with prominent columella, abnormally short nose and flat nasal bridge, abnormal ear configuration, bilateral longitudinal cheek dimples, everted lower lip, long philtrum, and maxillary hypoplasia. In addition, a happy and friendly disposition is considered to be the common symptom of this syndrome. Previous studies revealing the intraoral findings of this rare symptom are inadequate and the present report is the first one that presents a dental case involving Nablus syndrome in detail. The aim of this report is to contribute to the current literature through our oral findings in an NMFLS patient, presented at our clinic with toothache and through our treatment approach.