Epithelial-specific deletion of FAM20A leads to short root defects

Short Root Defects defined by a reduced ratio of root to crown, may culminate in root resorption and subsequent tooth loss, in spite of the absence of apparent symptoms. Such defects present considerable impediments to orthodontic treatment and restoration. Recent identification of Fam20a, an emergent pseudokinase, has been associated with enamel development and tooth eruption, yet its definitive role in root formation and eruption remains ambiguous. In this research, we initially ascertained that the targeted knockout of Fam20a within the epithelium led to truncated tooth roots, irregular breaks in the epithelial root sheath initiation of the WNT signaling pathway, and decreased expression of the cell polarity-related transcription factor Cdc42 in murine models. This was concomitant with the participation of the associated epithelial root sheath developmental pathways BMP2, Gli1, and Nfic. Furthermore, we observed that Fam20a predominantly affects the intraosseous eruption phase of tooth emergence. During this phase, the osteoclast peak around the mandibular first molar in cKO mice is delayed, leading to a slower formation of the eruption pathway, ultimately resulting in delayed tooth eruption in mice. The findings of this study enrich the extant knowledge regarding the role of Fam20a, suggesting its potential regulatory function in tooth root development through the WNT/β-catenin/Cdc42 pathway.

The Dynamic Interactions of a Multitargeting Domain in Ameloblastin Protein with Amelogenin and Membrane

The enamel matrix protein Ameloblastin (Ambn) has critical physiological functions, including regulation of mineral formation, cell differentiation, and cell-matrix adhesion. We investigated localized structural changes in Ambn during its interactions with its targets. We performed biophysical assays and used liposomes as a cell membrane model. The xAB2N and AB2 peptides were rationally designed to encompass regions of Ambn that contained self-assembly and helix-containing membrane-binding motifs. Electron paramagnetic resonance (EPR) on spin-labeled peptides showed localized structural gains in the presence of liposomes, amelogenin (Amel), and Ambn. Vesicle clearance and leakage assays indicated that peptide-membrane interactions were independent from peptide self-association. Tryptophan fluorescence and EPR showed competition between Ambn-Amel and Ambn-membrane interactions. We demonstrate localized structural changes in Ambn upon interaction with different targets via a multitargeting domain, spanning residues 57 to 90 of mouse Ambn. Structural changes of Ambn following its interaction with different targets have relevant implications for the multifunctionality of Ambn in enamel formation.

MicroRNA-145 regulates the proliferation of the human gastric cancer cells by targeting tuftelin 1 (TUFT1)

MicroRNA-145 (miR-145) has been shown to regulate the development of different human cancer. However, the role of miR-145 via modulation of tuftelin 1 (TUFT1) expression has not been studied in gastric cancer. TUFT1The results showed that gastric cancer tissues and cell lines exhibit significant (P<0.05) downregulation of miR-145. Overexpression of miR-145 significantly (P<0.05) inhibited the viability and colony formation of the MGC-803 gastric cancer cells. Annexin V/PI staining revealed that miR-145 exerts its tumor-suppressive effects via induction of apoptosis. The apoptotic cell percentage increased from 5.75% in negative control to 22.95% in miR-145 overexpressing MG-803 cells. This was also accompanied by upregulation of Bax and downregulation of Bcl-2 expression. TargetScan analysis and the dual luciferase assay revealed TUFT1 as the functional target of miR-145. The expression of TUFT1 was significantly (P<0.05) upregulated in gastric cancer tissues and cell lines. However, overexpression of miR-145 causes inhibition of the TUFT1 expression. Silencing of TUFT1 mimicked the tumor-suppressive effects of miR-145. However, tuftelin 1 overexpression attenuated the tumor-suppressive effect of miR-145 in MGC-803 gastric cancer cells. Taken together, the results of the present study indicate that miR-145 targets TUFT1 at translational level to exert its tumor suppressive effects in gastric cancer.

Amyloid-like amelogenin nanoribbons template mineralization via a low-energy interface of ion binding sites

Protein scaffolds direct the organization of amorphous precursors that transform into mineralized tissues, but the templating mechanism remains elusive. Motivated by models for the biomineralization of tooth enamel, wherein amyloid-like amelogenin nanoribbons guide the mineralization of apatite filaments, we investigated the impact of nanoribbon structure, sequence, and chemistry on amorphous calcium phosphate (ACP) nucleation. Using full-length human amelogenin and peptide analogs with an amyloid-like domain, films of β-sheet nanoribbons were self-assembled on graphite and characterized by in situ atomic force microscopy and molecular dynamics simulations. All sequences substantially reduce nucleation barriers for ACP by creating low-energy interfaces, while phosphoserines along the length of the nanoribbons dramatically enhance kinetic factors associated with ion binding. Furthermore, the distribution of negatively charged residues along the nanoribbons presents a potential match to the Ca–Ca distances of the multi-ion complexes that constitute ACP. These findings show that amyloid-like amelogenin nanoribbons provide potent scaffolds for ACP mineralization by presenting energetically and stereochemically favorable templates of calcium phosphate ion binding and suggest enhanced surface wetting toward calcium phosphates in general.

The Outcomes of Enamel Matrix Derivative on Periodontal Regeneration under Diabetic Conditions

Background and Objectives: Enamel matrix derivative (EMD) is a biomaterial used for periodontal regenerative therapy due to its properties of stimulating cementum development and bone synthesis. Diabetes is a chronic condition that affects healing and predisposes to infection. The aim of this review was to evaluate the current studies available on the application and results of EMD for periodontal regenerative therapy under diabetic conditions. Materials and Methods: Five databases (PubMed, ResearchGate, Scopus, Web of Science and Google Scholar) were searched for relevant articles, using specific keywords in different combinations. The inclusion criteria were clinical trials, case reports, case studies, and animal studies published in English, where periodontal treatment for bone defects includes EMD, and it is performed under diabetic conditions. Results: Of the 310 articles resulted in search, five studies published between 2012 and 2020 met the inclusion criteria and were selected for the current review. In human studies, the use of EMD in infrabony defects showed favorable results at follow-up. In animal studies, periodontal regeneration was reduced in diabetic rats. Conclusions: EMD might promote bone healing when used under diabetic conditions for the regenerative periodontal therapy. Due to limited number of studies, more data are required to sustain the effects of EMD therapy in diabetic settings.

[Effect of enamel matrix protein on osteogenic and adipogenic differentiation of dental pulp stem cells of deciduous teeth through miR-32]

PURPOSE

To explore the effect of enamel matrix proteins(EMPs) on osteogenesis and adipogenesis of stem cells from human exfoliated deciduous teeth SHED), and explore its molecular mechanism.

METHODS

SHEDs were used to detect the expression of its surface antigens CD73, CD146, CD34 and CD45 by flow cytometry. SHED was induced by OB osteogenic induction liquid, and then the osteogenic differentiation ability was measured by alizarin red staining. SHEDs were divided into 4 groups, NC group had invalid sequence shRNA interfered with SHED, EMPs group had invalid sequence shRNA interfered with SHED. Then 100 μg/L EMPs was used to interfere with SHED. In miR-32 inhibitor group, miR-32 shRNA plasmid was used to interfere with SHED; while in EMPs+miR-32 inhibitor group, 100 μg/L EMP was used to intervene SHED after silencing miR-32. QPCR was used to detect the expression of miR-32, dentin sialophosphoprotein (DSPP), dentin matrix protein 1, DMP-1, peroxisome proliferators-activated receptor γ (PPARγ) and CCAAT enhancer binding protein α (C/EBPα) gene expression; Western blot was used to detect the expression of DSPP, DMP-1, PPARγ and C/EBPα protein expression; Alizarin red staining was used to detect SHED osteogenic capacity; Oil red O staining was used to detect adipogenetic capacity of SHED.

RESULTS

The results of flow cytometry showed that SHED had positive expression of CD146 and CD73, and negative expression of CD34 and CD45, which was consistent with the characteristics of stem cell surface markers. Alizarin red staining and oil red O staining showed mineralized nodules and oil droplets increased significantly, consistent with the multi-directional differentiation characteristics of stem cells. Compared with NC group, the expression of miR-32 gene in EMPs group was significantly increased(P<0.05), and the expression of miR-32 in miR-32 inhibitor group and EMPs+miR-32 inhibitor group was significantly decreased(P<0.05). Compared with NC group, the expression of DSPP and DMP-1, the number of mineralized nodules in EMPs group were significantly increased(P<0.05), the expression of PPARγ and C/EBPa and the number of lipid droplets were significantly decreased (P<0.05), while the result of miR-32 inhibitor group was the opposite (P<0.05). Compared with miR-32 inhibitor group, there was no significant difference in the expression of DSPP, DMP-1, PPARγ and C/EBPα, number of mineralized nodules and oil droplets in EMPs+miR-32 inhibitor group(P>0.05). Compared with EMPs group, the expression of DSPP and DMP-1 and the number of mineralized nodules in EMPs+miR-32 inhibitor group were significantly reduced(P<0.05), while the expression of PPARγ and C/EBPα and the number of lipid droplets were significantly increased(P<0.05).

CONCLUSIONS

EMPs can regulate osteogenic and adipogenic differentiation of SHED by promoting the expression of miR-32.

The apically incised coronally advanced surgical technique (AICAST) for periodontal regeneration in isolated defects: a case series

OBJECTIVES

The aim of this retrospective case series was to report the performance up to 5 years of an innovative surgical design (the apically incised coronally advanced surgical technique [AICAST]) for the regenerative treatment of one- or two-walled intrabony periodontal lesions.

METHOD AND MATERIALS

After completion of standard step I to II periodontal therapy, nine isolated periodontal defects were treated through AICAST. The following clinical outcome measurements were collected before the surgical intervention and at the last available follow-up: probing pocket depth (PPD), recession depth (REC), and clinical attachment level (CAL). Periapical radiographs of the treated teeth were also taken at baseline and at the last available follow-up (18 months or 5 years postoperatively).

RESULTS

A mean (± standard deviation) PPD reduction of 6.05 ± 1.76 mm (P < .01), REC reduction of 1.15 ± 1.97 mm (P = .119), and CAL gain of 7.20 ± 2.13 mm (P < .01) were attained when comparing preoperative results with the last follow-up visit. CAL gain of 6 mm or more was reached in eight out of nine treated cases (88.9%), with a residual PPD of 2 to 3 mm in all the cases. Complete radiographic fill of the intrabony component was present in all the defects, while detectable suprabony radiographic filling was identified in two cases.

CONCLUSION

AICAST represents an innovative surgical design for the treatment of deep intrabony defects and the eventual reduction of the associated gingival recessions. Preliminary results show good performance in terms of clinical attachment gains and maintenance of the marginal tissues.

Boron as Boric Acid Induces mRNA Expression of the Differentiation Factor Tuftelin in Pre-Osteoblastic MC3T3-E1 Cells

The effects of boron on the formation and maintenance of mineralized structures at the molecular level are still not clearly defined. Thus, a study was conducted using MC3T3-E1 cells to determine whether boron affected mRNA expressions of genes associated with bone/alveolar bone formation around the teethMC3T3-E1 (clone 4) cells were cultured in media treated with boric acid at concentrations of 0, 0.1, 10, 100, or 1000 ng/ml. Total RNAs of each group were isolated on day 3. Gene expression profiles were determined by using RT² Profiler PCR micro-array that included 84 genes associated with osteogenic differentiation. Tuftelin1 mRNA expression was upregulated by all boron treatments. The upregulation was confirmed by quantitative RT-PCR using the tuftelin probe. While 100 ng/ml had no effect on the integrin-α2 (Itga2) transcript and 1 ng/ml boric acid induced Itga2 mRNA expression (2.1-fold), 0.1, 10, and 1000 ng/ml boric acid downregulated the integrin-α2 gene transcript 2.2-, 1.5-, and 2.1-fold respectively. While 0.1 ng/ml boric acid induced BMP6, increased BMP1r mRNA expression (1.5 fold) was observed in 1000 ng/ml boric acid treatment. The findings suggest that boron affects the regulation of the tuftelin1 gene in osteoblastic cells. Further studies are needed to establish that the beneficial actions of boron on alveolar bone and tooth formation and maintenance include an effect on the expression of the tuftelin1 gene.

The impact of supportive periodontal treatment on the outcome of regenerative surgical therapy in aggressive periodontitis patients

Objective: The aim was to evaluate the efficacy of periodontal regenerative therapy using enamel matrix derivatives (EMDs) in aggressive periodontitis patients, and to determine the contribution of maintenance via periodic supportive periodontal treatment. Method and materials: In total, 28 patients were evaluated, comprising 74 intrabony sites. In 50 sites EMD gel was applied, and in 24 sites EMD was combined with deproteinized bovine xenograft. Patients were assigned to a supportive periodontal treatment program; 18 patients fulfilled the program, defined as the well-maintained (WM) group; 10 did not comply, defined as the nonmaintained (NM) group. Probing depth (PD), clinical attachment level (CAL), and radiographic bone level (BL) were recorded. Data were compared presurgically (T0), 6 months postsurgery (T1), and 3 to 10 years posttreatment (T2). Results: Both surgical modalities achieved similar PD reduction, CAL gain, and BL gain, maintained over time. T1 to T2 showed a mean gain/loss of 0.21 ± 0.5 mm and 0.04 ± 1.1 mm, and -0.65 ± 3.0 mm and -0.73 ± 3.0 mm for PD and CAL, respectively, at the WM/NM groups, respectively. BL gain was 21.6% and 11.5% for the WM/NM groups, respectively (P < .05). The courses of the PD, CAL, and BL differed between the WM and NM groups during the observation periods (P < .05). Conclusion: Periodontal regeneration via EMD with/without the combination of deproteinized bovine xenograft can be maintained in aggressive periodontitis cases. It appears that periodic supportive periodontal treatment is a determinant factor in achieving this task.

Interactions with the aquaporin 5 gene increase the susceptibility to molar-incisor hypomineralization

OBJECTIVE

The aim of this study was to evaluate whether individual genetic factors involved in amelogenesis, the immune response and water channel proteins may increase the susceptibility to Molar-Incisor Hypomineralization (MIH) in Chinese children.

DESIGN

DNA samples were collected from 86 cases with MIH cases and 344 controls. Sixteen single-nucleotide polymorphisms (SNPs) were investigated. Logistic regression analysis was performed to assess association between SNPs and the risk of MIH.

RESULTS

Our results showed that the risk of MIH in the rs13115627-AA genotype carriers and the rs1784418-TT genotype carriers were significantly higher than that among those with the rs13115627-GG genotype (OR (95 % CI)) = 4.942 (0.658-37.131) and the rs1784418-CT genotype (OR (95 % CI)) = 2.023 (1.63-3.521). The population with the rs1800972-CC genotype and the rs1800972-C allele had a higher risk to develop MIH, OR (95 % CI) = 2.284 (1.267-4.115), OR (95 % CI) = 2.427 (1.493-3.953) respectively. In the Aquaporin 5(AQP5) gene, we individually analyzed two SNPs, rs1996315 and rs923911. We found no significant associations between them and MIH. However, in the analysis of the gene-gene interactions, we discovered a significant two-locus model (P = 0.023) involving rs1996315 and rs923911. Participants with the rs1996315-AG and rs923911-AC genotypes had the highest MIH risk, compared to participants with the rs1996315-GG and rs923911-CC genotypes, OR (95 % CI) = 3.603 (1.147-11.318).

CONCLUSION

This study showed that genetic variants in the AMBN, MMP20 and DEFB1 genes may contribute to MIH in the permanent dentition of children. Moreover, interactions among AQP5 gene may also increase the MIH susceptibility.

Early wound healing outcomes after regenerative periodontal surgery with enamel matrix derivatives or guided tissue regeneration: a systematic review

BACKGROUND

Proper wound healing after regenerative surgical procedures is an essential issue for clinical success. Guided tissue regeneration (GTR) and application of enamel matrix derivatives (EMD) are common means to regenerate periodontal tissues. Both methods bear considerable advantages due to their special characteristics, but also go along with certain disadvantages. Today, there is no consensus in the literature whether GTR or EMD show better results regarding early wound healing, which is considered a crucial stage in periodontal regeneration. Therefore, the aim of the present systematic review was to compare the early wound healing after regenerative periodontal surgery with either EMD or GTR treatment.

METHODS

An electronic literature search in PubMed was performed to identify randomized clinical trials (RCTs) or clinical trials (CTs) comparing regenerative surgery employing EMD and/or GTR in patients with chronic periodontitis. Among the finally included studies, a qualitative and quantitative data extraction regarding early wound healing parameters was performed. Primary outcome parameters were early wound healing index (EWH), flap dehiscence, membrane exposure, suppuration and abscess formation during the first 6 weeks. As secondary parameters, swelling and allergic reactions were assessed.

RESULTS

Seven studies reporting 220 intrabony periodontal defects in 199 patients were analysed. Flap dehiscence was observed in two studies in 12% of the GTR treated sites and in 10.3% of those treated with EMD. Membrane exposure was evaluated in five studies and was registered in the 28.8% of the defects, while no dehiscence was reported on the EMD group. Swelling was reported only in one study in 8/16 GTR sites and 7/16 EMD sites. Due to considerable heterogeneity of parameters no meta-analysis was possible.

CONCLUSIONS

Due to considerable heterogeneity of the published studies a clear beneficial effect of the EMD on the early wound healing outcomes after surgical treatment of periodontal intrabony defects cannot be confirmed. Standardized RCT studies are needed in order to allow for proper comparison of early wound healing after both types of surgical approaches.

Enamel biomimetics-fiction or future of dentistry

Tooth enamel is a complex mineralized tissue consisting of long and parallel apatite crystals configured into decussating enamel rods. In recent years, multiple approaches have been introduced to generate or regenerate this highly attractive biomaterial characterized by great mechanical strength paired with relative resilience and tissue compatibility. In the present review, we discuss five pathways toward enamel tissue engineering, (i) enamel synthesis using physico-chemical means, (ii) protein matrix-guided enamel crystal growth, (iii) enamel surface remineralization, (iv) cell-based enamel engineering, and (v) biological enamel regeneration based on de novo induction of tooth morphogenesis. So far, physical synthesis approaches using extreme environmental conditions such as pH, heat and pressure have resulted in the formation of enamel-like crystal assemblies. Biochemical methods relying on enamel proteins as templating matrices have aided the growth of elongated calcium phosphate crystals. To illustrate the validity of this biochemical approach we have successfully grown enamel-like apatite crystals organized into decussating enamel rods using an organic enamel protein matrix. Other studies reviewed here have employed amelogenin-derived peptides or self-assembling dendrimers to re-mineralize mineral-depleted white lesions on tooth surfaces. So far, cell-based enamel tissue engineering has been hampered by the limitations of presently existing ameloblast cell lines. Going forward, these limitations may be overcome by new cell culture technologies. Finally, whole-tooth regeneration through reactivation of the signaling pathways triggered during natural enamel development represents a biological avenue toward faithful enamel regeneration. In the present review we have summarized the state of the art in enamel tissue engineering and provided novel insights into future opportunities to regenerate this arguably most fascinating of all dental tissues.

Treatment of Periodontal Intrabony Defects Using Enamel Matrix Derivative: Surgical Reentry After an Observation Period of at Least 5 Years

The purpose of this study was to assess the healing of periodontal intrabony defects treated using enamel matrix derivative (EMD) after at least 5 years of follow-up. Six patients with seven intrabony defects were included in the study. Treatment with EMD yielded a mean clinical attachment level gain of 4.3 ± 2.4 mm, a mean probing depth reduction of 4.7 ± 2.1 mm, and a mean gingival recession increase of 0.7 ± 1.8 mm. Reentry measurements showed a complete resolution of the intrabony defect in five cases, while in two cases a residual intrabony component was recorded. The present study indicates that treatment using EMD provided good clinical outcomes maintained in most cases over a period of at least 5 years.

[In vitro study on the properties of guided bone regeneration of new type chitosan-based thermosensitive hydrogel membranes]

PURPOSE

To prepare chitosan/β-glycerophosphate salt (CS/β-GP) thermosensitive hydrogel membranes loaded enamel matrix proteins and detect the guided bone regeneration properties.

METHODS

A newly membrane was synthesized using thermal phase inversion property of the CS/ββ-GP system. The membrane was synthesized and added with protein BSA. The concentration of protein was detected at different time points by enhanced protein assay kit, and the protein release curve was drawn. CS/β-GP membrane added EMPs (1.0 g) as group A, CS/β-GP (1.0 g) membrane as group B and nothing as blank control group (group C). They were co-cultured with ST2 cells. The mechanical properties of the membranes were tested in vitro, and the compatibility properties were detected by MTT method. The activity of ALP was assayed by PNPP method. The data was analyzed by SPSS 16.0 software package.

RESULTS

Membranes with different concentration of CS/β-GP could release protein slowly more than 12 days, and the total quantity of the released protein increased with the concentration of the β-GP. The changes of mechanical properties of the membranes were not significant (P>0.05). The OD value of group A, B and C had statistically significant difference in the MTT test. The values of group A and B were higher than that of group C, while the value of group A was higher than that of group B (P<0.05). The activities of ALP were different in the three groups. The activities of group A and B were higher than that of the blank control group (P<0.05).The difference in expression of ALP between group A and B was also statistically significant. The expression in group A was higher than that in group B (P<0.05).

CONCLUSIONS

The new type CS/β-GP membrane shows property of guided bone regeneration in vitro, which have the potentials for clinical use.

Pregnane X receptor knockout mice display aging-dependent wearing of articular cartilage

Steroid and xenobiotic receptor (SXR) and its murine ortholog, pregnane X receptor (PXR), are nuclear receptors that are expressed at high levels in the liver and the intestine where they function as xenobiotic sensors that induce expression of genes involved in detoxification and drug excretion. Recent evidence showed that SXR and PXR are also expressed in bone tissue where they mediate bone metabolism. Here we report that systemic deletion of PXR results in aging-dependent wearing of articular cartilage of knee joints. Histomorphometrical analysis showed remarkable reduction of width and an enlarged gap between femoral and tibial articular cartilage in PXR knockout mice. We hypothesized that genes induced by SXR in chondrocytes have a protective effect on articular cartilage and identified Fam20a (family with sequence similarity 20a) as an SXR-dependent gene induced by the known SXR ligands, rifampicin and vitamin K2. Lastly, we demonstrated the biological significance of Fam20a expression in chondrocytes by evaluating osteoarthritis-related gene expression of primary articular chondrocytes. Consistent with epidemiological findings, our results indicate that SXR/PXR protects against aging-dependent wearing of articular cartilage and that ligands for SXR/PXR have potential role in preventing osteoarthritis caused by aging.

[Localization of enamelin in developing rat incisor by immunofluorescence]

PURPOSE

To investigate the expression of enamelin in developing rat incisor.

METHODS

Immunofluorescence staining for the specimens of developing rat incisor was used to localize the expression of enamelin.

RESULTS

Enamelin was not detected at the proliferation phase, and early differentiation phase in preameloblasts. At the advanced differentiation phase, enamelin expressed weakly in ameloblasts and odotoblasts. At the early maturation phase enamelin was detected in ameloblasts and odotoblasts. Enamelin expressed strongly in ameloblasts and enamel matrix but strongly in odotoblasts at the intermediate maturation phase and weakly at the advanced maturation phase. Enamelin was not found in the other stages and position.

CONCLUSION

Enamelin,involved in enamel and dentin matrix formation, may play an important role in signal transduction of matrix formation. Supported by Project of the "Tenth-Five Year" Science Support Plans and Project "211" of Tongji University (Grant No.1504102011).

A transgenic mouse line with a 58-kb fragment deletion in chromosome 11E1 that encompasses part of the Fam20a gene and its upstream region shows growth disorder

Growth disorder is an umbrella term for a range of abnormal growth patterns, such as unusually fast or slow growth in infants or children. The causes of growth disorder include hormonal irregularities, chronic disease, complications during pregnancy or genetic conditions. A complex trait such as body size is influenced by multiple genes as well as environmental factors, giving rise to a continuous spectrum of phenotypes. This causal complexity makes discovery of the genetic determinants of growth disorder rather difficult. We here report our discovery of a transgenic mouse line exhibiting growth disorder, which we happened to discover in the course of generating transgenic mice expressing a viral gene. Although these mice did not express any corresponding viral mRNA or protein due to a deletion in the transgene, they showed slow growth in the 5 weeks after birth and ceased growing thereafter, while maintaining a weight equivalent to that of 3-week-old normal mice. Histopathological analysis of the organs of these mice revealed that malnutrition and metabolic disorder occurred at 5 weeks after birth in the liver. Genetic analysis has revealed that the growth disorder is associated with a 58-kb fragment deletion in chromosome 11E1 that encompasses part of the Fam20a gene and part of its upstream region. The present study thus points out for the first time the possible link between Fam20a mutation and growth disorder.

[Effect of enamel matrix proteins on the growth of apatite coating on chemically modified titanium]

PURPOSE

To evaluate the effects of enamel matrix proteins(EMPs) on the growth of apatite coatings on dual thermo-etching or alkali heat-treated pure titanium(Ti).

METHODS

EMPs were extracted from porcine tooth germs and identified by SDS-PAGE. Dual thermo-etching treated or alkali-heat treated Ti samples, then, were exposed in a blank or EMPs containing(150microg/mL) modified simulated body fluid(m-SBF) at 37degrees centigrade for 7 days. SEM, EDS, XRD and FTIR were employed to observe or analyze the morphologies, element components and crystal structures of the apatite coatings.

RESULTS

In dual thermo-etching-treated groups, almost no calcium-phosphate deposits were found on the titanium surfaces of control group and some amount of calcium-phosphate deposits with the main element components of Ca, P, O and C, however, formed on those of experimental group. But in alkali heat-treated groups, the apatite coatings proved to be carbonate hydroxyapatite formed on the titanium surfaces of both control group and experimental group, and the apatite coatings of the latter were found porous(300-600nm) and uneven.

CONCLUSIONS

Alkali heat-treatment is in favor of apatite deposition, and EMPs can promote apatite deposition on both dual thermo-etching and alkali heat-treated pure titanium surfaces.

[Enamel matrix proteins in the treatment of intrabony defects: A cochrane systematic review]

PURPOSE

The purpose of this study was to systematically review the evidence for efficacy of enamel matrix proteins (EMPs) in comparison with guided tissue regeneration(GTR) for the treatment of intrabony defects.

METHODS

The selected studies were pooled from seven major electronic databases from 1997 to 2008 for randomized controlled trials(RCTs) with at least 6 months of follow-up. Several English journals were hand-searched. In addition, a Meta-analysis was presented regarding the clinical results during regeneration with EMPs or GTR. Outcome measures were probing depth(PD) reduction, clinical attachment level (CAL) gain, and gingival recession(GR).

RESULTS

A meta-analysis showed that the baseline between the two groups were comparative, but there were no statistical significant differences in PD reduction and CAL gain and GR was observed between the two regenerative treatments.

CONCLUSIONS

There is no evidence of important differences between EMPs and GTR in PD reduction, CAL gain and GR. EMPs can gain the similar clinical effects as GTR when treated with intrabony defects. Supported by Research Project of Education Bureau of Liaoning Province (Grant No.20061021).

A comparative study of the long term results of root coverage with connective tissue graft or enamel matrix protein: 24-month results

BACKGROUND

The objective of this study was to compare the 24 month results of coronally advanced flap + enamel matrix derivates (EMD+CAF) and CAF+ connective tissue graft (CTG+CAF) in the treatment of Miller Class I recession defects.

METHODS

Twelve patients with bilateral gingival recessions were treated with EMD+CAF or CTG+CAF. Vertical recession depth (VRD), keratinized tissue width (KTW), clinical attachment level (CAL), and clinical probing depth (CPD) were measured preoperatively, 1 and 2 years post surgery. A paired t-test and independent t-test were used to compare differences for the measured characters within and between groups, respectively.

RESULTS

After 24 months, a significant decrease in VRD was observed in CAF + EMD (3.33+/- 0.30 mm) and CAF + CTG (4.5 +/- 0.28 mm) treated sites. There was also a significant increase in KTW (0.83+/- 0.23 mm versus 2.08+/- 0.14 mm in EMD+CAF and CTG+CAF sites, respectively). The gain in CAL was 3.54 +/- 0.38 mm and 4.45+/- 0.30 mm in the EMD+CAF and CTG+CAF groups, respectively. There were significant differences between the treatments for VRD, CAL, and KTW at the end of study.

CONCLUSIONS

The CTG+CAF procedure seems to provide better long-term results than the EMD+CAF in obtaining root coverage, increasing the KTW and CAL gain.

[Effects of enamel matrix proteins loaded in chitosan thermosensitive hydrogel on bone marrow stromal cells in vitro]

PURPOSE

To investigate the effects of enamel matrix proteins (EMPs ) on proliferation, alkaline phosphate (ALP) activity of bone marrow stromal cells (BMSCs) seeded on the scaffold of chitosan thermosensitive hydrogel.

METHODS

Chitosan thermosensitive hydrogel was prepared and its slow-releasing effect of EMPs was checked by coomassie blue staining kit. Rat BMSCs were obtained from rat bone marrow aspiration and cultured in DMEM medium with 10% fetal bovine serum (FBS). Rat BMSCs were exposed to various concentrations of EMPs (0,50,100 and 150 microg/mL) and their proliferation rates were assessed by MTT assay. The proliferation rates and ALP activity of rat BMSCs were examined by MTT assay and ALP kit when BMSCs cultured on the scaffolds of chitosan thermosensitive hydrogel loading with or without 100 microg/mL EMPs .The data was statistically analyzed with SPSS11.0 software package for a parametric one-way analysis of variance (ANOVA) and two-sample t test.

RESULTS

The release of EMPs in chitosan thermosensitive hydrogel lasted for more than 3 weeks. In DMEM medium, 50 microg/mL EMPs significantly enhanced BMSCs proliferation from day 3 over the experiment(P<0.01). In chitosan thermosensitive hydrogel scaffolds loading 100 microg/mL EMPs, both the proliferation at day 3 and 5 (P<0.05)and the ALP activity at day 7 (P<0.05) and 9(P<0.01) of BMSCs in the experiment were promoted.

CONCLUSION

EMPs loaded on the chitosan thermosensitive hydrogel exhibits significant effects on proliferation and ALP activity of rat BMSCs.

[Effects of enamel matrix proteins on attachment, proliferation and pre-mRNA of type I collagen synthesis of human dermal fibroblast cells in vitro]

OBJECTIVE

To investigate the influence of enamel matrix proteins (EMPs) on the attachment, proliferation and pre-mRNA of type I collagen synthesis of cultured human dermal fibroblast cells.

METHODS

Human dermal fibroblast cells were obtained from human acrobystia and cultured in DMEM medium with 10% FBS. The 3rd to 6th passage cells were used. Ninety-six-well plates and 6-well plates were pre-coated with different concentrations of EMPs (50, 100, 150 and 200 microg/mL). (1) The cell attachment experiment: 0.2 mL cells suspension at the concentration of 1 x 10(6)/mL was added to the pre-coated 96-well plates as the experimental groups (groups A, B, C and D based on different concentrations of EMPs). At 1.5, 3.0, and 4.5 hours after inoculation, the attached cells were measured by MTT method. (2) The cell proliferation experiment: 0.2 mL cells suspension at the concentration of 5 x 10(4)/mL was added to the pre-coated 96-well plates as the experimental groups (groups A1, B1, C1 and D1 based on the different concentrations of EMPs). At 2, 4, 6 and 8 days after inoculation, the cells were measured by MTT method. (3) The synthesis experiment of pre-mRNA: 2 mL cells at the concentration of 1 x 10(6)/mL was added to the pre-coated 6-well plates as the experimental groups (groups A2, B2, C2 and D2 based on different concentrations of EMPs). At 5 days after inoculation, the synthesis of pre-mRNA was measured by RT-PCR method. Human dermal fibroblast cells were added to the un-coated plates as the control groups.

RESULTS

(1) The cell attachment experiment: There were significant differences in attachment cells between the control group, group A and the groups B, C and D (P < 0.05). There were no significant difference between group A and control group (P < 0.05). (2) The cell proliferation experiment: At 2 days, there were no significant differences in absorbance between the control group and the experimental groups (P > 0.05); at 4 days and 6 days, the absorbance of groups B1 (0.598 +/- 0.020 and 0.639 +/- 0.016 ), C1 (0.582 +/- 0.017 and 0.641 +/- 0.020) and D1 (0.574 +/- 0.021 and 0.635 +/- 0.021) was significantly higher than that of the control group (0.548 +/- 0.021 and 0.605 +/- 0.019, P < 0.05); at 8 days, the absorbance of group B1 (0.629 +/- 0.012) and group C1 (0.631 +/- 0.014) was significantly higher than that of the control group (0.606 +/- 0.031, P < 0.05). (3) The synthesis experiment of pre-mRNA: The synthesis of type I collage pre-mRNA of groups B2, C2 and D2 was significantly higher than that of the control group.

CONCLUSION

EMPs stimulate human dermal fibroblast cell attachment, proliferation and synthesis of type I collage pre-mRNA, and its maximal effect can be achieved at the concentration of 100 microg/mL.

[Osteoplastic materials in the treatment of parodontosis]

Efficiency of bioactive osteoplastic composition HA-phage at a surgical stage of combined treatment of chronic generalized periodontitis was examined. The results obtained in the control and experimental groups proved that HA-phage allows reducing the time of treatment and to achieve remission of the disease. Out of 92 patients with chronic generalized periodontitis 52 undertook microplasmic scalpel-irradiator in complex treatment. The treatment course comprises 3-5 procedures. The quantity of manipulations is determined by the pathological process. Before and after the treatment the radiographic investigations were carried out in persons of both groups. 18 months later after the operation a bone regeneration was shown in 87,8% cases in the investigated group and 60,1%--in the control group patients. The therapy has shown positive results. So, the new method of treatment of chronic generalized periodontitis may prove to be more practical in clinical dentistry. Currently, it is possible to isolate highly purified BMSSCs from bone marrow using STRO-1. The management of periodontal defects has been an ongoing challenge in clinical periodontics. This is mainly a result of the fact that the tissues which comprise the periodontium, the periodontal ligament, and the cementum and alveolar bone represent three unique tissues in their own right. Thus, reconstruction of the periodontium is not just a simple matter of regenerating one tissue but involves at least three quite diverse and unique tissues. Taking into account the results of recent studies we hypothesize that mesenchymal stem cells transplantation should be a perspective approach in the treatment of periodontal defects. For this purpose we plan to perform an experimental investigations which will include an induction of periodontitis, purification of the bone marrow stem cells and their transplantation.

[Effect of boron and fluoride on the expression of enamelin in rat incisor]

OBJECTIVE

To investigate the effects of overdose fluoride, boron and two factors on the expression of enamelin in rat incisor.

METHODS

32 Wistar rats were randomly divided into 4 groups. Group I: The distilled water was given. Group II: 220 mg/L NaF were given. Group III: 382 mg/L Na2B4O2.10H2O were given. Group IV: 220 mg/L NaF and 382 mg/L Na2B4O2.10H2O were given. The rats were sacrificed in the eighth week. HE staining was used to observe the morphology of ameloblasts. Immunohistochemical staining was used for study the expression of enamelin in rat incisors.

RESULTS

The results showed that the expression of enamelin was reduced in the group II (P<0.01). Compared with group I, the expression of enamelin in group IV had no significant difference. The expression of enamelin in group IV and group II had significant difference (P<0.01).

CONCLUSION

The overdose fluoride can inhibit the expression of enamelin. The effection was weaken when boron added. Boron reduced the toxicity of fluoride on teeth.

Root coverage with Emdogain/AlloDerm: a new way to treat gingival recessions

The recession of the gingival margin is becoming a more prominent condition in the oral situation of many patients and should be treated at its earliest detection. The multifactorial etiology, decision modality, and current trends in the treatment of gingival recession are discussed in this article. The surgical technique of choice depends on several factors, but among the different surgical protocols available, the clinician should select one that will minimize surgical trauma and achieve predictable esthetic results. All of the approaches described in this article can effectively treat deep and shallow Class I or II buccal recessions. Recently, as an alternative to autogenous gingival grafts in root coverage procedures, enamel matrix derivative (Emdogain) and acellular dermal matrix allograft (AlloDerm) were utilized to correct these gingival defects, negating the morbidity and the requirement for a second palatal surgical procedure. Emdogain or AlloDerm materials used alone or in combination are a predictable treatment for root coverage, are relatively easy to perform (although they are technique sensitive), present low patient morbidity, offer a significant increase in the percentage of root coverage and amount of keratinized tissue, and should be part of the periodontal plastic surgery armamentarium.

[Exclusion of candidate genes in a family with amelogenesis imperfecta]

OBJECTIVE

To localize the gene (s) responsible for autosomal dominant hypocalcified amelogenesis imperfecta in a Chinese family.

METHODS

A Chinese family which was diagnosed as autosomal dominant hypocalcified amelogenesis imperfecta (AD) was studied. Venous blood from nineteen family members was collected and genomic DNA was extracted from the blood. Eight short tandem repeats (STRs) spanning five hereditary AI candidate genes were selected and linkage analysis between the genetic markers and the disease loci was performed.

RESULTS

Genotype of the eight STRs were acquired, the linkage analysis result can not support that the gene for AI pedigrees was linked to ENAM, AMBN, TUF1, KLK4 or MMP-20.

CONCLUSION

The results can not support all proposed candidate gene regions as causal for autosomal dominant hypocalcified AI in this family. These linkage findings provide further evidence for genetic heterogeneity among families with autosomal dominant AI and indicate that, at least, some forms of autosomal dominant AI are not caused by a gene in the five most commonly reported AI candidate genes.

[Effects of EMPs on growth and attachment of human BMSCs]

PURPOSE

The present study is to evaluate the effects of enamel matrix proteins(EMPs) on the attachment, spreading and proliferation of human bone marrow stromal cells(hBMSCs) in vitro.

METHODS

Human BMSCs were obtained from human bone marrow aspiration and cultured in DMEM medium with 10% fetal bovine serum (FBS). EMPs was added into medium in several concentrations (50,100, 200, 300 microg/ml) as experimental groups. BMSCs were cultured without EMPs as control group. Attachment ability of hBMSCs was detected by counting cell number. Cell spreading rates were performed at various culture times by analysis of micrographs taken at predetermined sites of each wells. Cell proliferation rates were assessed by MTT assay. Data was statistically analyzed with SAS6.12 software for one-way ANOVA.

RESULTS

It was shown that BMSCs were cultured successfully in vitro. There was no significant change between the control group and experimental groups in cell attachment and cell spreading rate. However, the proliferation of BMSCs was significantly stimulated by EMPs in a dose- and time-dependent manner. EMPs at a concentration of 200 microg/ml significantly enhanced BMSCs proliferation (P < 0.05).

CONCLUSION

EMPs could promote the proliferating ability of human BMSCs, but have no effects on its attachment and spreading.Supported by National "863" Project (Grant No. 2002AA205013), Shanghai Municipal Education Development Fund(Grant No.2002-02) and Research Fund of Science and Technology Committee of Shanghai Municipality (Grant No.04dz05601).

[Effect of overdose fluoride on the expression of enamelin in rat mandibular incisor]

OBJECTIVE

To observe the effect of overdose fluoride on the expression of enamelin in rat mandibular incisor.

METHODS

Twenty Wistar rats were divided randomly into two groups. Animals were maintained in standard environment with free access to food and distilled water (control group) or water added with 100 mg/L F-(experimental group). The rats were killed in the eighth week. HE staining was used to observe the morphology of ameloblasts. Immunohistochemical staining was adopted to study the expressions of enamelin in rat incisor.

RESULTS

The ameloblasts of the treated rat were arranged in multi-layer. The ameloblasts in group II were thinner than those in group I. The structure of enamel matrix was in disorder. The expressions of enamelin in ameloblasts and odontoblasts were obviously inhibited in group II (P < 0.01).

CONCLUSION

The overdose fluoride inhibits the secretion of enamelin and leads to the abnormal development of enamel matrix.

[Preparation of enamel matrix proteins controlled release microspheres and their biological effects on the proliferation and differentiation of human periodontal ligament cells in vitro]

OBJECTIVE

To prepare enamel matrix proteins (EMPs) loaded dextran-based hydrogel microspheres (EMPs-dex-MPs), and to evaluate their EMPs controlled release property and their biological effects on the proliferation and differentiation of human periodontal ligament cells (PDLCs) in vitro.

METHODS

Using dimethylbenzene as the oil phase, EMPs-dex-MPs were achieved by emulsion-chemical crosslinking technique. The process of the recombination preparation was optimized by orthogonal factorization method. The configuration and size of EMPs-dex-MPs were determined by scanning electron microscope. The EMPs loading content and encapsulation rate of EMPs-dex-MPs, and their biodegradation characteristic were studied by routine analysis methods. Dynamic dialysis method was used to determine the release characteristic of EMPs-dex-MPs in vitro and its influencing factors. The proliferation of cultured PDLCs was measured by MTF method and the differentiation of PDLCs was measured by their alkaline phosphatase (ALP) activities.

RESULTS

The results showed that EMPs-dex-MPs were homogenous and stable with the average diameter 25 microm, and the EMPs loading content was (32.8 +/- 1.2)%, the encapsulation rate was (78.9 +/- 1.0)%. Under 9% physiological saline solution contained a very thimbleful quantity of dextranase EMPs-dex-MPs could be biodegraded completely during about 40 days. The in vitro experiments showed that about 80% of EMPs could be released out in 20 days. Using EMPs-dex-MPs could enhance the proliferation responses and ALP activities of PDLCs more than 12 days.

CONCLUSION

As a new sustained release system of growth factors, the dex-MPs is stable, workable and biodegradable. EMPs-dex-MPs, whose drug release can be controlled by preparation technique, may be more effective in promoting periodontal tissue regeneration.

Effect of GBR in combination with deproteinized bovine bone mineral and/or enamel matrix proteins on the healing of critical-size defects

OBJECTIVES

To evaluate the effect of guided bone regeneration (GBR) in combination with or without deproteinized bovine bone mineral (DBBM) and/or an enamel matrix derivative (EMD) on the healing of critical-size calvarial defects.

MATERIAL AND METHODS

Forty rats were used. In all animals, a standardized critical-size calvarial defect was created surgically. The animals were randomly allocated into 4 groups of 10 animals each. Group A: One calvarial defect was left untreated, while the galeal and the cerebral aspect of the contralateral defect were covered with a bioresorbable membrane (GBR). Group B: One calvarial defect was filled with EMD, while the contralateral defect was treated with GBR and EMD. Group C: One defect was filled with DBBM, while the contralateral defect was treated with combination of GBR and DBBM. Group D: One defect was filled with DBBM combined with EMD, while the contralateral defect was treated with combination of GBR, DBBM and EMD. The healing period was 4 months. Five specimens from each group were macerated and the length, the width and the vertical dimension (thickness) of the remaining defect were evaluated by a stereomicroscope. The remaining specimens in each group were analyzed histologically.

RESULTS

The defects of the macerated specimens that were left untreated or were treated only by EMD, DBBM and combination of EMD and DBBM did not present predictably complete healing of the defects. All the defects where GBR was applied alone or combined with DBBM and/or EMD presented always complete healing (P<0.05). The combined use of GBR with EMD and/or DBBM did not offer any significant advantage above GBR alone in terms of healing of the length and the width of the defect. However, the vertical dimension of the defect was significantly higher (P<0.05) in the GBR-treated specimens of Groups C and D. The histological analysis supported these findings.

CONCLUSION

The predictability of bone formation in critical-size defects depends mainly on the presence or absence of barrier membranes (GBR). The combined use with deproteinized bovine bone mineral and/or enamel matrix proteins did not significantly enhance the potential for complete healing provided by the GBR procedure.

[Clinical comparison between guided tissue regeneration and induced tissue regeneration]

AIM

The aim of the present study was to evaluate, over a period of 1 y, 3 different surgical methods for the treatment of periodontal bone defects.

METHODS

Thirty-six infrabone defects, at least 4 mm in depth, in non-smokers were enrolled in the study. Of these, 12 were treated with guided tissue regeneration (GTR) using a resorbable membrane with collagen, 12 with enamel matrix derivative (EMD) gel and 12 with a modified Widman flap (MWF). The pocket depth, attachment loss and gingival recession both before commencement of therapy and after an interval of 1 y are reported.

RESULTS

The reduction in pocket depth was 4 mm, 4.4 mm, and 4.5 mm, respectively, for the control group, GTR group and EMD group. The attachment gain for the respective treatments was: MWF, 2 mm; GTR, 2.8 mm; EMD, 2.9 mm. Gingival recession was: MWF, 1.8 mm; GTR, 1.5 mm; EMD, 1.1 mm.

CONCLUSION

These findings show the efficacy of the 3 methods in the treatment of bone defects, but none of the 3 emerges as being statistically superior to the others 2.

Porcine enamel matrix derivative enhances the formation of reparative dentine and dentine bridges during wound healing of amputated rat molars

We examined the biological effects of porcine enamel matrix derivative (EMD; Emdogain) on the formation of reparative dentine and dentine bridges in rat molars after pulp amputation. The pulp chambers of upper molars of Wistar rats were perforated and the amputated pulp surfaces were directly capped with either EMD or its carrier propylene glycol alginate (PGA) as control. The cavities were then restored with glass-ionomer cement. On post-amputation days 4-30, the dissected maxillae were examined by light and electron microscopy. In PGA-capped pulp, reparative dentine had been formed over the dentine walls under the prepared cavity on day 7 post-amputation and its thickness extended until day 30. On day 30, as well as reparative dentine formation, diffuse calcification had occurred beneath the amputated wound surfaces. Dentine bridge formation under the amputated coronal pulp surface was observed in 18.2% of amputated pulp on day 30. In EMD-capped pulp, reparative dentine had already been formed by odontoblast-like cells over the dentine walls, already on day 4 post-amputation, and its thickness extended until day 30. The Ca and P weight % and Ca/P ratio of reparative dentine matrix were similar to those of pre-existing dentine matrix, and these values were not different between PGA and EMD-capped pulp. Dentine bridge formation was observed in 27.3% of EMD-capped pulp on day 30. Our results suggest that EMD enhances the formation of both reparative dentine and dentine bridges during wound healing of amputated rat molar pulp.

Evaluation of PCR-based beef sexing methods

Analysis of the sex of beef meat by fast and reliable molecular methods is an important measure to ensure correct allocation of export refunds, which are considerably higher for male beef meat. Two PCR-based beef sexing methods have been optimized and evaluated. The amelogenin-type method revealed excellent accuracy and robustness, whereas the bovine satellite/Y-chromosome duplex PCR procedure showed more ambiguous results. In addition, an interlaboratory comparison was organized to evaluate currently applied PCR-based sexing methods in European customs laboratories. From a total of 375 samples sent out, only 1 false result was reported (female identified as male). However, differences in the performances of the applied methods became apparent. The collected data contribute to specify technical requirements for a common European beef sexing methodology based on PCR.

Clinical evaluation of an enamel matrix protein derivative (Emdogain) combined with a bovine-derived xenograft (Bio-Oss) for the treatment of intrabony periodontal defects in humans

The purpose of the present study was to compare the treatment of deep intrabony defects with a combination of an enamel matrix protein derivative (EMD; Emdogain) and a bovine-derived xenograft (BDX; Bio-Oss) to BDX alone. Twenty-four healthy patients, each of whom displayed one intrabony defect, were randomly treated with a combination of EMD + BDX (test) or with BDX alone (control). Soft tissue measurements were made at baseline and 1 year following the therapy No differences in any of the investigated parameters were observed at baseline between the two groups. No adverse healing response was observed in any of the patients. At 1 year after therapy, the sites treated with EMD + BDX showed a reduction in probing pocket depth (PPD) from 10.0 +/- 1.5 mm to 4.3 +/- 1.4 mm and a change in clinical attachment level (CAL) from 10.9 +/- 2.0 mm to 6.2 +/- 1.9 mm (P <.0001). In the group treated with BDX, the PPD was reduced from 9.7 +/- 2.4 mm to 3.2 +/- 0.7 mm and the CAL changed from 10.1 +/- 2.3 mm to 5.2 +/- 1.2 mm (P <.0001). Hard tissue fill was observed radiographically in all defects. Both treatments resulted in significant improvements of PPD and CAL. However, no statistically significant differences in any of the investigated parameters were observed between the test and control groups. Both therapies led to significant improvements of the investigated clinical parameters.

Y-STR DNA amplification as biological evidence in sexually assaulted female victims with no cytological detection of spermatozoa

Identification of spermatozoa is the biological evidence most often sought in specimens from rape victims. Absence of spermatozoa usually terminates biological investigations, and the victim's testimony can be contested. We assessed the utility and reliability of PCR amplification using Y-chromosomal STR polymorphisms in specimens from female victims of sexual assault with negative cytology. One hundred and four swabs without spermatozoa detected by cytology were collected from 79 alleged sexually assaulted female victims and amplification of Y-STR and of amelogenin was performed.Overall, Y-chromosome was detected and evidenced sexual penetration in 28.8% of swabs. In the population of victims examined more than 48 h after the sexual assault, Y-STR were still evidenced in 30% of the cases. These results show that swabs should be taken from victims for Y-chromosome DNA typing even after long delays between sexual assault and medical examination.

Identifying sex chromosome abnormalities in forensic DNA testing using amelogenin and sex chromosome short tandem repeats

Forensic DNA laboratories worldwide have begun using multiplexed STR systems to decrease analysis time and increase sample throughput. The loci used in these systems are basically "nonsense" regions of human DNA. However, due to the chromosome on which some of these loci are located, various genetic abnormalities can sometimes be detected. This paper will show one such abnormality--Klinefelter's Syndrome--and the process used to show the possibility of this defect in two undiagnosed males using peak height ratios at the Amelogenin locus, and X-Y STRs.

Surgical technique for treatment of infrabony defects with enamel matrix derivative (Emdogain): 3 case reports

A surgical protocol is described for the placement of Emdogain enamel matrix derivative during new attachment procedures. Three cases with infrabony defects were treated and a significant probing attachment level (PAL) gain, probing depth reduction, and bone fill were evident on clinical probing and during reentry procedures. The first patient presented a combined one-walled and circumferential defect at a maxillary central incisor. After 1 year the PAL gain was 7 mm. The second case showed a 3-walled defect distal to a maxillary canine. After 1 year the PAL gain was 8 mm, and a reentry procedure showed an almost total fill of the defect. The third patient presented a combined one- and 3-walled defect in the most apical part of the mesial aspect of a maxillary central incisor. One year after the surgical procedure, an orthodontic treatment was performed in this patient. After 6 more months the soft tissue showed a very good esthetic appearance, the papilla height was fully maintained, and there was a PAL gain of 5 mm; 18 months after surgery, reentry showed a significant regeneration of hard tissue that was impossible to probe. Because of these encouraging clinical results, further studies should be initiated to investigate the efficacy of the enamel matrix derivative in new attachment procedures.

Treatment of intrabony periodontal defects with an enamel matrix protein derivative (Emdogain): a report of 32 cases

Enamel matrix proteins, including Emdogain, have been proposed as a new modality for regenerative periodontal treatment. However, limited information is available concerning the clinical applicability and therapeutic results with Emdogain. The aim of the present study was therefore to evaluate the clinical outcome following the application of Emdogain in the treatment of intrabony periodontal defects. Twenty-eight patients with marginal periodontitis (thirty-two 2- and 3-walled intrabony defects) were included in this study. The following parameters were evaluated prior to treatment and 8 months after treatment: probing pocket depth, recession of the gingival margin, and clinical attachment level. The postoperative healing phase was uneventful in all cases. There were no complications such as allergic reactions, abscess formation, or infections throughout the entire study period. The mean probing pocket depth was reduced from 8.7 +/- 1.5 mm at baseline to 4.3 +/- 1.6 mm after 8 months (P < 0.001), the mean gingival recession increased from 1.8 +/- 1.2 mm to 3.3 +/- 0.9 mm, and the mean clinical attachment level changed from 10.6 +/- 1.9 mm to 7.6 +/- 1.8 mm (P < 0.001). New hard tissue formation was radiographically observed in 26 of the 32 defects. The present results suggest that the treatment of intrabony periodontal defects with Emdogain may lead to significant improvements of all of the investigated clinical parameters. However, controlled histologic and clinical trials are needed to compare this treatment modality with other conventional and regenerative periodontal surgical methods.

Enamel matrix derivative for periodontal reconstructive surgery: technique and clinical and histologic case report

This paper describes a step-by-step technique for the application of Emdogain, a new enamel matrix derivative (EMD) graft material, for periodontal reconstructive surgery. A case report is presented with a 1-year follow-up. The rationale for use and advantages and disadvantages of EMD are discussed. An additional human histologic case report demonstrates that the formation of new bone, cementum, and periodontal ligament is possible following the use of EMD.

DYS19 and amelogenin in artificial blood stains with defined amounts of male and female cells

The sensitivity of the DYS19 and the amelogenin STR systems for amplifying Y-specific fragments was assayed using artificial bloodstains with varying amounts of male and female (non-template) DNA in different ratios. The study confirmed the high sensitivity of both systems in detecting male-specific PCR fragments in stains containing 10-25 template molecules even in the presence of large amounts of female DNA in the mixture by silver-stain detection. However, blood mixtures which contain less than 10% male cells could be reliably typed only when at least 100 template molecules were present in the artificial bloodstain, due to increasing amounts of hemoglobin from the female blood which is a PCR inhibitor.

Ancient DNA in human bone remains from Pompeii archaeological site

aDNA extraction and amplification procedures have been optimized for Pompeian human bone remains whose diagenesis has been determined by histological analysis. Single copy genes amplification (X and Y amelogenin loci and Y specific alphoid repeat sequences) have been performed and compared with anthropometric data on sexing.

Studies on the changes in developing enamel caused by ingestion of high levels of fluoride in the rat

Exposure to chronic high levels of fluoride results in the formation of fluorosed enamel. Although enamel may be more susceptible to fluorotic effects at certain stages of development, fluoride at sufficiently high levels may affect enamel at all stages of formation. Careful study of the changes in enamel caused by chronic fluoride ingestion is needed to understand more fully the mechanisms involved in the formation of fluorotic enamel. This paper discusses the various studies we have completed to define the changes, in developing enamel of the rat incisor, caused by long-term ingestion of fluoride in drinking water. Fluoride has been found to inhibit secretion of enamel proteins. Changes in the maturation stage of enamel formation include the retention of amelogenin proteins during early maturation. The various mechanisms which have been investigated in the formation of fluorosed enamel include a direct effect of fluoride on the enamel organ, and specific interactions of fluoride with the extracellular enamel matrix. Although the same amount of protease appears to be secreted in fluorosed and control enamel, a delay in the digestion of amelogenin protein occurs. This suggests that fluoride may directly or indirectly inhibit the protease present in fluorosed enamel to slow the proteolysis of amelogenins.

Selective adsorption of porcine-amelogenins onto hydroxyapatite and their inhibitory activity on hydroxyapatite growth in supersaturated solutions

The selective adsorption of amelogenins onto synthetic hydroxyapatite (HA) and their inhibitory activity on the seeded HA crystal growth were investigated using enamel proteins obtained from the outer layer of immature porcine-enamel (soft, cheeselike in consistency) of developing permanent incisors. Special interests were paid to the effect of a postsecretory degradation of the original amelogenin(s) on their adsorption and inhibitory activity. In the adsorption studies, it was apparent that the originally secreted amelogenin (25 K), proline, and histidine-rich protein (2a), as well as the higher molecular weight components (60-90 K), showed a strong adsorption affinity onto the HA. This adsorption of protein 2a was related to its inhibition of the crystal growth of seeded HA in a dilute supersaturated solution. On the other hand, the partially degraded product (20 K) of amelogenins, protein 2b, lost the high adsorption affinity onto the HA, and consequently showed no significant inhibitory activity. The observed selective adsorption of protein 2a onto HA was apparent at pH 6.0 and pH 7.4 even in the presence of dissociative solvents, such as 3 M urea or 2 and 4 M guanidine-HCl; however, this selective behavior was sensitive to changes in pH, and was not displayed at pH values of 7.8 or 10.8. The results suggest that the originally secreted amelogenin 2a may play an active role in amelogenesis, and that enamel mineralization could be regulated by the secretion of amelogenins and their inactivation through partial enzymic degradation, prior to their complete removal.

Studies of the secondary structures of amelogenin from bovine tooth enamel

Circular dichroism and Fourier transform infrared spectroscopic studies of the major amelogenin protein of developing bovine tooth enamel in solution and in the solid state suggest a unique secondary structure containing beta-sheet and repetitive beta-turn structures. The repetitive beta-turn structure at the C-terminal end results from the unique primary structure of amelogenin.

Protein conformation in rat tooth enamel

Orientated 0.47 nm reflections in X-ray diffraction patterns of developing rat tooth enamel were confirmed using a wide range of specimen preparations and experimental conditions. This indicates that some of the organic matrix proteins adopt a beta-sheet conformation.