The classification as well as the clinical manifestations of hereditary malformations of dentin are of great concern and have been deeply elucidated. The understanding of its genetic basis also increases progressively. Dentin sialophosphoprotein (DSPP) is the pathogenic gene of dentinogenesis imperfecta type Ⅱ, dentinogenesis imperfecta type Ⅲ and dentin dysplasia type Ⅱ. In this article, the classification of DSPP mutations as well as the resultant dysfunction of the mutant DSPP are summarized respectively and the corresponding clinical manifestations are analyzed. This work will provide a reference for the diagnosis and treatment of hereditary malformations of dentin.
Humans ; Dentinogenesis Imperfecta/pathology* ; Mutation ; Extracellular Matrix Proteins/genetics* ; Phosphoproteins/genetics* ; Sialoglycoproteins/genetics* ; Dentin/pathology*

A splicing mutation in VPS4B can cause dentin dysplasia type I (DD-I), a hereditary autosomal-dominant disorder characterized by rootless teeth, the etiology of which is genetically heterogeneous. In our study, dental follicle cells (DFCs) were isolated and cultured from a patient with DD-I and compared with those from an age-matched, healthy control. In a previous study, this DD-I patient was confirmed to have a loss-of-function splicing mutation in VPS4B (IVS7 + 46C > G). The results from this study showed that the isolated DFCs were vimentin-positive and CK14-negative, indicating that the isolated cells were derived from the mesenchyme. DFCs harboring the VPS4B mutation had a significantly higher proliferation rate from day 3 to day 8 than control DFCs, indicating that VPS4B is involved in cell proliferation. The cells were then replenished with osteogenic medium to investigate how the VPS4B mutation affected osteogenic differentiation. Induction of osteogenesis, detected by alizarin red and alkaline phosphatase staining in vitro, was decreased in the DFCs from the DD-I patient compared to the control DFCs. Furthermore, we also found that the VPS4B mutation in the DD-I patient downregulated the expression of osteoblast-related genes, such as ALP, BSP, OCN, RUNX2, and their encoded proteins. These outcomes confirmed that the DD-I-associated VPS4B mutation could decrease the capacity of DFCs to differentiate during the mineralization process and may also impair physiological root formation and bone remodeling. This might provide valuable insights and implications for exploring the pathological mechanisms underlying DD-I root development.
ATPases Associated with Diverse Cellular Activities ; genetics ; Case-Control Studies ; Cell Differentiation ; genetics ; Cells, Cultured ; Dental Sac ; cytology ; Dentin Dysplasia ; genetics ; pathology ; physiopathology ; Endosomal Sorting Complexes Required for Transport ; genetics ; Humans ; Mutation ; genetics ; Osteogenesis ; genetics ; RNA Splicing ; genetics

Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin (PA) for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin-dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2% chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.
Chlorhexidine ; chemistry ; pharmacology ; Collagenases ; pharmacology ; Dental Bonding ; Dental Cements ; chemistry ; Dental Stress Analysis ; instrumentation ; Dentin ; drug effects ; ultrastructure ; Dentin-Bonding Agents ; chemistry ; Gelatinases ; pharmacology ; Humans ; Hydroxyproline ; analysis ; Matrix Metalloproteinase 8 ; pharmacology ; Matrix Metalloproteinase Inhibitors ; chemistry ; pharmacology ; Proanthocyanidins ; chemistry ; pharmacology ; Stress, Mechanical ; Surface Properties ; Tensile Strength ; Tooth Demineralization ; pathology ; physiopathology

Deletion or mutation of dentin matrix protein 1 (DMP1) leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate (Pi) or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmp1-null (Dmp1(-/-)), Klotho-deficient (kl/kl), Dmp1/Klotho-double-deficient (Dmp1(-/-)/kl/kl) and wild-type (WT) mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography (μCT), scanning electron microscopy (SEM), histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmp1(-/-) (a low Pi level) or kl/kl (a high Pi level) mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice (a high Pi level) displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment (a high Pi level).
Ameloblasts ; pathology ; Amelogenesis ; physiology ; Animals ; Apoptosis ; physiology ; Cell Differentiation ; physiology ; Dental Enamel ; pathology ; Dental Pulp ; pathology ; physiology ; Dental Pulp Cavity ; pathology ; Dentin ; abnormalities ; pathology ; Dentinogenesis ; physiology ; Extracellular Matrix Proteins ; genetics ; physiology ; Glucuronidase ; genetics ; Homeostasis ; physiology ; Hyperphosphatemia ; physiopathology ; Immunohistochemistry ; Mice ; Mice, Knockout ; Microscopy, Electron, Scanning ; Odontoblasts ; pathology ; Odontogenesis ; physiology ; Ossification, Heterotopic ; genetics ; pathology ; Phosphates ; physiology ; Tooth Calcification ; physiology ; X-Ray Microtomography

The present study aims to evaluate the effect of Galla chinensis compounds on the remineralization of two artificial root lesions morphous in vitro. Sixty bovine dentine blocks were divided into two groups and individually treated with two levels of demineralization solutions to form erosive and subsurface artificial carious lesions in vitro. Each group was then divided into three subgroups, each of which were treated with a remineralization solution (positive control), deionized water (negative control), or 4 000 mg⋅L(-1) aqueous solutions of Galla chinensis extract. The dentine blocks were then subjected to a pH-cycling regime for 7 days. During the first 4 days, the daily cycle included 21-h deal and 3-h demineralization applications. The dentine blocks were dealt with the entire day during the remaining 3 days. Two specimens from each of the treatment groups were selected and observed under a polarized light microscope. Data collected using a laser scanning confocal microscope were computerized and analyzed. Galla chinensis extract clearly enhanced the remineralization of both erosive lesion and subsurface lesion patterns in the specimens (P<0.05). The level of remineralization of the erosive lesion by Galla chinensis extract was lower than that of the subsurface lesion (P<0.05). In addition, the remineralization of the subsurface lesion by Galla chinensis extract was higher than that of the remineralization solution (P<0.05). No significant difference between the remineralization of erosive lesions by Galla chinensis extract and the remineralization solution was observed (P>0.05). So Galla chinensis extract has the potential to improve the remineralization of artificial root lesions under dynamic pH-cyclic conditions, indicating its potential use as a natural remineralization medicine.
Animals ; Cariostatic Agents ; therapeutic use ; Cattle ; Dentin ; pathology ; Drugs, Chinese Herbal ; chemistry ; therapeutic use ; Gallic Acid ; therapeutic use ; Hydrogen-Ion Concentration ; Hydrolyzable Tannins ; therapeutic use ; Microscopy, Confocal ; Microscopy, Polarization ; Polyphenols ; therapeutic use ; Random Allocation ; Root Caries ; drug therapy ; Tooth Remineralization

To obtain the caries experience and, plaque accumulation severity and pit and fissure morphology in first permanent molars in 7-8 children in Wuhan, as a reasonable prediction of caries risk and preventive attention in the future, a convenient sample of five primary schools in the vicinity of the Wuhan University School and Hospital of Stomatology was drawn. Two calibrated examiners orally examined all present grade 2 children in the classroom, using standard caries plaque and tooth morphology criteria. Dental caries was scored at enamel (D(2)) and dentine (D(3)) for tooth and surface level. Independent variables were age, gender and school. Data analysis used analysis of variance and t-test. The sample comprised 1 043 7- and 8-year-olds. The prevalence of dental caries in permanent dentition was 8.7% and in primary dentition, 68.7%. Mean Decayed, Missing, Filled Teeth/S (DMFT/S) scores were 0.11 and 0.14, respectively. Mean dmft/s scores were 2.8 and 5.0. The d-component constituted 75% of the d(3)mft index, while enamel carious lesions constituted 36% of the total number of carious lesions (d(2,3)-component). Prevalence of medium and deep pits and fissures was 84.6%. Prevalence of medium and severe plaque accumulation was 67.4%. Prevalence of dental caries in the deciduous and permanent dentitions of 7- to 8-year-old children was high. Deep pits and fissures in high caries risk children should be sealed.
Child ; China ; epidemiology ; DMF Index ; Dental Caries ; epidemiology ; prevention & control ; Dental Enamel ; pathology ; Dental Fissures ; pathology ; Dental Plaque Index ; Dentin ; pathology ; Dentition, Permanent ; Female ; Humans ; Male ; Molar ; pathology ; Prevalence ; Tooth, Deciduous

OBJECTIVETo evaluate the nanoleakage and ultramorphology of four self-etching adhesives.

METHODSSixteen freshly extracted, caries-free human third molars were selected. A flat dentin surface was exposed by removing occlusal enamel. All teeth were randomly divided into four groups acorrding to four different self-etch adhesive: Adper Prompt (A), iBond (B), Xeno III (C) and SE Bond (D). The dentin were bonded with dentin adhesive system according to manufacturer's directions. Composite layers were built up incrementally. The specimens were sectioned longitudinally across the resin-dentin interface into 4.0 mm×0.9 mm sticks and then traced with ammoniacal silver solution. Epoxy resin-embedded sections were prepared for transmission electron microscope (TEM) to observe nanoleakage. The images were qualitatively compared by NIH software, and data was analyzed by SPSS.

RESULTSDifferent thickness of hybrid layer and adhesives layer were observed for each adhesive. The hybrid layer of A, C was thicker than that of B, D, and adhesive layer of D was thicker than the others. The extent of nanoleakage varied among different adhesives: A (45.02 ± 9.49), B (43.97 ± 8.55), C (27.02 ± 10.86), D (12.94 ± 2.07). D presented significantly less silver deposition than any of the others did (P < 0.05).

CONCLUSIONSThe thickness of hybrid layer and adhesive layer vary among the four adhesives. The shape and extent of nanoleakage of each adhesive are also different. Two-step system shows less nanoleakage than one-step systems do.

Acid Etching, Dental ; Adhesives ; chemistry ; Dental Leakage ; pathology ; Dentin ; ultrastructure ; Dentin-Bonding Agents ; chemistry ; Humans ; Methacrylates ; chemistry ; Microscopy, Electron, Transmission ; Molar, Third ; Resin Cements ; chemistry

OBJECTIVETo investigate the clinical characteristics and risk factors of dentine hypersensitivity in smaller cities and rural area in Sichuan province.

METHODSThe examinee aged 20 - 69 years old were interviewed and divided into five age groups (20 - 29, 30 - 39, 40 - 49, 50 - 59 and 60 - 69). The random sampling methods were performed in this study. A total of eight spots were survied, including 4 communities and 4 spots in rural area of Sichuan province. The information about the examinee's age, gender, occupation, education level, tooth brushing methods, the frequencies of eating fresh fruits and fruit juices and so on, were asked and recorded. All subjects were further diagnosed by a blast of air from a triple syringe connected to an air compressor at a pressure of 4 atm under room temperature of about 19 - 24°C.

RESULTSThe premolars were the most commonly affected, followed by the first molar. The exposed root surface was the most commonly affected position [63.87% (663/1038)]. The first premolar had the greatest number of teeth with dentine hypersensitivity [29.96% (311/1038)]. Different tooth had different sensitive position. Female, too much time of using a tooth brush, and hydrochloric acid in gastric juice were risk factors for dentine hypersensitivity (OR value = 2.175, 1.157, 1.760).

CONCLUSIONSDentine hypersensitivity is influenced by multiple factors. Prevention and treatment need be performed by improving general oral health and periodontal conditions.

Adult ; Aged ; Bicuspid ; pathology ; China ; Cross-Sectional Studies ; Cuspid ; pathology ; Dentin Sensitivity ; epidemiology ; pathology ; Feeding Behavior ; Female ; Gingival Recession ; complications ; Humans ; Hydrochloric Acid ; adverse effects ; Male ; Middle Aged ; Molar ; pathology ; Oral Health ; Periodontal Attachment Loss ; complications ; Prevalence ; Risk Factors ; Rural Population ; Sex Factors ; Surveys and Questionnaires ; Tooth Root ; pathology ; Toothbrushing ; Young Adult

Animals ; Collagenases ; metabolism ; Dental Bonding ; Dental Caries ; enzymology ; Dentin ; enzymology ; pathology ; Gelatinases ; metabolism ; Humans ; Matrix Metalloproteinase 14 ; metabolism ; Matrix Metalloproteinase 20 ; metabolism ; Matrix Metalloproteinase 3 ; metabolism ; Matrix Metalloproteinases ; metabolism ; Sclerosis

OBJECTIVETo observe the influence of chemomechanical caries removal on dentin adhesion by scanning electron microscope.

METHODSThe ultrastructure of dentin surfaces and adhesives-dentin bonding interfaces after caries removal by chemomechanical method or drilling were observed.

RESULTSLess smear layer in dentin surface, resin tags in the interface between dentin and Prime&Bond NT/compomer and numerous resin tags and more uniform and closer hybrid layer in the interface between dentin and Adper Prompt-L-Pop/composite were found in chemomechanical preparation than in drilling preparation.

CONCLUSIONSChemomechanical caries removal can benefit dentin adhesion.

Acid Etching, Dental ; Dental Bonding ; Dental Caries ; pathology ; therapy ; Dental High-Speed Equipment ; Dentin ; drug effects ; ultrastructure ; Dentin-Bonding Agents ; pharmacology ; Humans ; Microscopy, Electron, Scanning ; Surface Properties