Association of Three Genetic Loci with Molar Incisor Hypomineralization in Polish Children.

BACKGROUND: Molar incisor hypomineralization (MIH) is a qualitative, demarcated enamel defect of hypomineralization affecting one to four first permanent molars, often with incisor involvement. Its etiology is complex. However, evidence suggests the influence of genetic factors, potentially including the single nucleotide polymorphisms (SNPs) rs2889956, rs4811117 and rs13058467, which were previously linked to MIH in a genome-wide association study of German children. The aim was to replicate analyses of possible associations between the SNPs and molar incisor hypomineralization in Polish children. METHODS: The final study group consisted of 778 children aged 126-168 months old. Saliva samples were taken, and genomic DNA was extracted and genotyped using beadchip microarrays. RESULTS: Among the 778 subjects, there were 68 (8.7%) subjects with MIH and 710 (91.3%) subjects without MIH. There were no significant differences in distributions in age, sex, or the frequency of caries in permanent dentition between the MIH and non-MIH groups. The rs2889956, rs4811117, and rs13058467 genotype distributions in the studied group conformed to the expected Hardy-Weinberg equilibria, and there were no significant differences in the distributions of their alleles or genotypes between the MIH and non-MIH groups. CONCLUSION: Our replication study did not confirm highly significant associations between the single nucleotide polymorphisms rs2889956, rs4811117, and rs13058467 with molar incisor hypomineralization in Polish children.

Evaluation of Gingival Phenotype in the Early Transitional Dentition Phase in Children-Comparison of Three Non-Invasive Methods.

Gingival phenotype (GP) is determined based on the thickness and width of the gingival tissue. An evaluation of GP is essential for adequate treatment planning and outcome monitoring, including orthodontic treatments in a paediatric population. The present study aimed to compare the reliability of the visual and TRAN methods with that of the ultrasound biometer measurements in the early transitional dentition phase. One hundred ninety three generally healthy, 7-year-old children were examined. An assessment of GP was performed by a paedodontist and a periodontist. The average thickness of the gingiva was 0.76 ± 0.36 mm, which was classified as a thin GP. The agreement between a visual assessment and the biometric ultrasound measurements reached the highest (94%) level when assessing a very thin GP (Spearman's rank correlation coefficient r = 0.37, p < 0.01). Similarly, 99% agreement in the diagnosis of a thin GP was recorded for the TRAN and ultrasound methods (Spearman's rank correlation coefficient r = 0.49, p < 0.001). In total, 86% of cases diagnosed as having a thick GP using the TRAN method turned out to be thin according to the ultrasound measurements. The dentist's specialization and professional experience in the assessment of GP were irrelevant (Spearman's rank correlation coefficient r = 0.49, p < 0.001). All methods tested in the present study were proven to be easy to perform and well accepted by the children. The visual assessment and TRAN methods, despite the fact that they enabled the diagnosis of a thin GP (crucial for treatment planning), cannot be recommended during the teeth replacement period. A misdiagnosis of thick GP may deprive a young at-risk patient of special supervision, which may develop into mucogingival deformities. A biometric ultrasound, although expensive, allows for reliable assessment of the gingiva thickness when needed.

Gingival Phenotype Changes and the Prevalence of Mucogingival Deformities during the Early Transitional Dentition Phase-A Two-Year Longitudinal Study.

Thin gingival phenotype (GPh) may contribute to periodontal tissue breakdown and recession development. Thus, the early identification of thin GPh in children can allow proper preventive care and the identification of children at risk during orthodontic treatment. The present long-term study aimed to monitor GPh changes, i.e., thickness (GT) and width of attached gingiva (AGW) during the early transitional dentition phase, as well as its potential associations with the mucogingival deformities. MATERIALS AND METHODS: 83 systematically healthy children were examined twice with an interval of 2 years. Probing depth, GT and AGW at mandibular incisors, vestibular depth, type of lower lip frenum attachment and mucogingival defects were recorded. RESULTS: 95.2% of participants at baseline and 93.9% at 2-year examination expressed thin GPh. During the transition from the deciduous to permanent dentition, GT and AGW declined, but the GT of permanent incisors already erupted at the baseline examination increased in the observation period. CONCLUSIONS: Gingival phenotype undergoes changes in the early transitional dentition phase. In spite of the thin gingival phenotype, only single pseudo-recessions and primary shallow vestibule were noticed.

Multidisciplinary Management of a Double Immature Permanent Tooth: A Case Report.

Fused or geminated teeth require complex and multi-faceted treatment to maintain their health, functionality, and appearance. The current paper describes the multidisciplinary/minimally invasive treatment of fused immature permanent teeth. A 9-year-old-girl with an abnormally large left permanent maxillary lateral incisor was referred to the Paediatric Outpatient Clinic. The treatment plan of the referring orthodontist included the extraction of left maxillary lateral incisor, which was fused to a supernumerary tooth, followed by subsequent orthodontic and prosthetic treatments. In the paraclinic evaluation, cone-beam computed tomography (CBCT) showed two separate roots and two root canals, with communication between the pulp chambers of the double teeth. The modified treatment plan was to section the geminated tooth, remove the supernumerary and save the lateral incisor. During the sectioning procedure, the pulp of the remaining tooth was inevitably exposed. Direct pulp capping with Biodentine™ was performed. Next, glass-ionomer cement was applied as a temporary restoration and the supernumerary tooth was removed. The distal surface of the tooth was restored two weeks later so as to re-establish the original shape of the lateral incisor. Clinical and radiographic control examinations revealed that the tooth was symptom-free. Follow-up appointments after 3, 6, 12 and 18 months included standard clinical examinations and sensivity tests including electric pulp testing, which showed a fully functional, healthy tooth with apical maturation. Careful clinical and radiographic evaluations/examinations are essential for determining the correct treatment of a double tooth. The proposed multidisciplinary and minimally invasive treatment of the double tooth using a bioactive cement may facilitate the maturation of immature teeth and result in a desirable aesthetics and function.

Factors affecting the outcomes of direct pulp capping using Biodentine.

INTRODUCTION: This study aimed to evaluate the prognostic value of factors with regard to the treatment outcome of direct pulp capping using Biodentine (Septodont, Saint-Maur-des-Fossés, France), in permanent teeth in which the pulps were exposed during caries removal. METHODS: Between 2010 and 2014, 112 teeth with deep carious lesions underwent direct pulp capping. The patients were followed up at 2-3 months and 1-1.5 years with a routine examination on both recall visits. Periapical radiographs were taken at 1-1.5 years. Lack of patient complaints, positive reactions to cold and electric testing, no sensitivity to percussion, and no widening of the periapical ligament indicated success. The Fisher exact test was used for statistical analysis. The significance level was P = .05. RESULTS: Eighty-six teeth were available for 1-1.5 years follow-up. The overall success rate was 82.6%. Only age had a significant effect on the pulpal survival rate: the success rate was 90.9% in patients younger than 40 years and 73.8% in patients 40 years or older (P = .0480). Sex, initial or secondary caries treatment, occlusal or cervical/proximal caries, delayed placement of permanent filling, tooth position, and arch type did not influence the outcome. CONCLUSIONS: A patient's age influenced the outcome of direct pulp capping using this new calcium silicate cement. CLINICAL RELEVANCE: Asymptomatic vital permanent teeth with cariously exposed pulp can be treated successfully by direct pulp capping using Biodentine.

Molecular Routes to Group IV Magnesium and Calcium Nanocrystalline Ceramics.

The effect of alkaline-earth-metal alkoxides on the protonolysis of Cp2M'Cl2 (M' = Ti, Zr, Hf; Cp = cyclopentadiene) was investigated. This approach enabled the design of compounds with well-defined molecular structures to generate high-purity binary metal oxides. Single-source molecular precursors with structures of [M2M'2(µ3-OEt)2(µ-OEt)4(OEt)6(EtOH)4] with M = Mg and M' = Ti (1), Zr (2), and Hf (3), [Ca6Ti4(µ6-O)2(µ4-O)2(µ3-OEt)12(OEt)12(EtOH)6Cl4] (4), and [M2M'2(µ4-O)(µ-OEt)5(OEt)4(EtOH)4Cl]n with M = Ca and M' = Zr (5) and Hf (6) were prepared via elimination of the cyclopentadienyl ring from Cp2M'Cl2 as CpH in the presence of M(OEt)2 and ethanol (EtOH) as a source of protons. Meanwhile, similar reactions involving the initial substitution of Cl ligands by OEt groups in Cp2M'Cl2 (M' = Ti, Zr, Hf) resulted in the formation of [M2M'2(µ3-OEt)2(µ-OEt)4(OEt)6(EtOH)4] with M = Ca and M' = Ti (7), Zr (8), and Hf (9). The precursors were characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray structural analysis. Magnesium compounds 1-3 decomposed at 750-850 °C to give MgTiO3 along with small amounts of Mg2TiO4, Mg2Zr5O12, or Mg2Hf5O12 binary metal oxides. The thermolysis of calcium compounds 4 and 7-9 led to highly pure CaTiO3, CaZrO3, or CaHfO3 perovskite-like oxide particles with diameters of 20-30 nm.

Synthesis of Aluminosilicates Containing a Ba(Sr)-O-Al-O-Si Arrangement of Natural Feldspar Mineral.

We report a facile route to multicomponent complexes of [M{(µ-ddbfo)2Al(OSiR3)2}2] (M = Ba, Sr; ddbfoH = 2,3-dihydro-2,2-dimethylbenzofuran-7-ol; R = Ph, OtBu) as new efficient single-source routes to barium and strontium celsian feldspar Ba(Sr)Al2Si2O8. The resulting complexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction. These compounds calcined at 1100 °C to give porous material Ba(Sr)Al2Si2O8·2SiO2 as an amorphous silica matrix containing spherical oxide nanocrystals of celsian feldspar of ca. 5 nm diameter, as evidenced by transmission and scanning electron microscopies.

Unexpected Reactions between Ziegler-Natta Catalyst Components and Structural Characterization of Resulting Intermediates.

In this work, we investigated precursors and procatalysts with well-defined crystal structures and morphologies in Ziegler-Natta systems to improve our understanding of the nature of the active metal sites. Molecular cluster precursors such as [Mg4Ti3(µ6-O)(µ3-OH)3(µ-OEt)9(OEt)3(EtOH)3Cl3], [Mg4Ti3(µ6-O)(µ3-OH)(µ3-OEt)2(µ-OEt)9(OEt)3(EtOH)3Cl3], and [Mg6Ti4(µ6-O)2(µ3-OH)4(µ-OEt)14(OEt)4(EtOH)2Cl2] were prepared via simple elimination of the cyclopentadienyl ring from Cp2TiCl2 as CpH in the presence of magnesium metal and ethanol. Titanocene dichloride acts as both a source of titanium and a magnesium-chlorinating agent. The resulting novel complexes were characterized using single-crystal X-ray diffraction. In these compounds, Ti(OEt)4 molecules are grafted onto Mg4 and Mg6 ethoxide cubane-like surfaces; this strongly affects the procatalyst morphology, which is transferred to the polymer. Mg4(OR)8 units act as carriers for the AlR3 co-catalyst, resulting in return of alkyl functions to the Ti center.

Alkaline Earth Metal Zirconate Perovskites MZrO3 (M=Ba(2+), Sr(2+), Ca(2+)) Derived from Molecular Precursors and Doped with Eu(3+) Ions.

The effect of alkaline earth metal alkoxides on the protonation of zirconocene dichloride was investigated. This approach enabled the design of compounds with preset molecular structures for generating high-purity binary metal oxide perovskites MZrO3 (M=Ba(2+), Sr(2+), Ca(2+)). Single-source molecular precursors [Ba4 Zr2 (µ6 -O)(µ3 ,η(2)-OR)8 (OR)2(η(2) -HOR)2 (HOR)2 Cl4], [Sr4 Zr2 (µ6 -O)(µ3 ,η(2)-OR)8 (OR)2 (HOR)4 Cl4], [Ca4 Zr2 (µ6-O)(µ3 ,η(2)-OR)8 (OR)2 Cl4], and [Ca6 Zr2 (µ2 ,η(2)-OR)12 (µ-Cl)2 (η(2) -HOR)4 Cl6 ]⋅8 CH2 Cl2 were prepared via elimination of the cyclopentadienyl ring from Cp2 ZrCl2 as CpH in the presence of M(OR)2 and alcohol ROH (ROH=CH3OCH2 CH2OH) as a source of protons. The resulting complexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction. The compounds were then thermally decomposed to MCl2 /MZrO3 mixtures. Leaching of MCl2 from the raw powder with deionized water produced highly pure perovskite-like oxide particles of 40-80 nm in size. Luminescence studies on Eu(3+)-doped MZrO3 revealed that the perovskites are attractive host lattices for potential applications in display technology.

Transformation of barium-titanium chloro-alkoxide compound to BaTiO3 nanoparticles by BaCl2 elimination.

In this Article, we present how the molecular precursor of binary oxide material having an excess of alkali earth metal can be transformed to the highly phase pure BaTiO3 perovskite. Here, we synthesized and compared two barium-titanium complexes with and without chloride ligands to determine the influences of different ligands on the phase purity of binary oxide nanoparticles. We prepared two barium-titanium complexes, i.e., [Ba4Ti2(µ6-O)(OCH2CH2OCH3)10(HOCH2CH2OCH3)2(HOOCCPh3)4] (1) and [Ba4Ti2(µ6-O)(µ3,η2-OCH2CH2OCH3)8(µ-OCH2CH2OCH3)2(µ-HOCH2CH2OCH3)4Cl4] (2). The barium-titanium precursors were characterized using elemental analysis, infrared and nuclear magnetic resonance spectroscopies, and single-crystal X-ray structural analysis, and their thermal decomposition products were compared. The complex 1 decomposed at 800 °C to give a mixture of BaTiO3 and Ba2TiO4, whereas 2 gave a BaCl2/BaTiO3 mixture. Particles of submicrometer size (30-50 nm) were obtained after leaching of BaCl2 from the raw powder using deionized water. Preliminary studies of barium titanate doped with Eu(3+) sintered at 900 °C showed that the dominant luminescence band arose from the strong electric dipole transition, (5)D0-(7)F2.

Cyclopentadienyl/alkoxo ligand exchange in group 4 metallocenes: a convenient route to heterometallic species.

A simple and efficient strategy for the synthesis of nonorganometallic heterometallic clusters from cheap organometallic precursors is reported. This unique synthetic method involves elimination of the cyclopentadienyl ring from Cp(2)MCl(2) (M = Ti, Zr, Hf) as CpH in the presence of M'L(2) or M'L'(2) (M' = Ca, Sr, Mn; CH(3)OCH(2)CH(2)OH = LH or (CH(3))(2)NCH(2)CH(2)OH = L'H) in an alcohol as a source of protons. In the reactions presented, a series of compounds, [Ca(4)Ti(2)(mu(6)-O)(mu(3),eta(2)-L)(8)(eta-L)(2)Cl(4)] (1), [Sr(4)Hf(2)(mu(6)-O)(mu(3),eta(2)-L)(8)(eta-L)(2)(eta-LH)(4)Cl(4)] (2), [Ca(4)Zr(2)(mu(6)-O)(mu-Cl)(4)(mu,eta(2)-L)(8)Cl(2)] (3), [Sr(4)Ti(2)(mu(6)-O)(mu(3),eta(2)-L)(8)(eta-L)(2)(eta-LH)(2)Cl(4)] (4), [Ca(4)Zr(2)Cp(2)(mu(4)-Cl)(mu-Cl)(3)(mu(3),eta(2)-L)(4)(mu,eta(2)-L)(4)Cl(2)] (5), [CaTiCl(2)(mu,eta(2)-L')(3)(eta-L'H)(3)][L'] (6), [Ca(2)Ti(mu,eta(2)-L')(6)Cl(2)] (7), [Mn(4)Ti(4)(mu-Cl)(2)(mu(3),eta(2)-L)(2)(mu,eta(2)-L)(10)Cl(6)] (8), and [Mn(10)Zr(10)(mu(4)-O)(10)(mu(3)-O)(4)(mu(3),eta(2)-L)(2)(mu,eta(2)-L)(16)(mu,eta-L)(4)(eta-L)(2)Cl(8)] (9), were obtained in good yield. All of the complexes were characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray structural analysis. Complex 8 belongs to a group of magnetic clusters that consists of Mn(4) subunits held together by two mu-Cl bridges. Compounds 6 and 7 underwent thermal decomposition, yielding an alternative source for some heterometallic oxides, which were analyzed by X-ray powder diffraction.

Unexpected cyclopentadienyl/alkoxo ligand exchange in titano- and zirconocene. New opportunities.

A simple new route to access heterometallic alkoxo precursors for a wide range of materials is reported. This unique synthetic method comprises elimination of the cyclopentadienyl ring from Cp2MCl2 (M = Ti, Zr) as CpH in the presence of M'(OR)2 (M' = Ca, Mn; OR = OCH2CH2OCH3 or OEt) in an alcohol as a source of protons. In one-pot reactions, we have prepared four different compounds with Ti2Ca4(mu6-O), Cp2Zr2Ca4(mu4-Cl), Zr10Mn10(mu3-O) 14, and Cp3Ti2(mu-OEt)2 motifs. The compounds were characterized by single-crystal X-ray structural analysis and NMR spectroscopy.