Application of cryopreservation to tooth germ transplantation for root development and tooth eruption.

We cryopreserved mouse tooth germs with widely open cervical margins of the enamel organ to overcome difficulties in cryoprotectant permeation and tested their efficacy by transplanting them into recipient mice. The upper right first molar germs of 8-day-old donor mice were extracted and categorized into the following four groups according to cryopreservation time: no cryopreservation, 1 week, 1 month, and 3 months. The donor tooth germs were transplanted into the upper right first molar germ sockets of the 8-day-old recipient mice. The upper left first molars of the recipient mice were used as controls. The outcome of the transplantation was assessed at 1, 2, and 3 weeks after transplantation. Stereomicroscopic evaluation revealed that most of the transplanted teeth erupted by 3 weeks after transplantation. Micro-computed tomography analysis revealed root elongation in the transplanted groups as well as in the controls. There was no significant difference between the cryopreserved and non-cryopreserved transplanted teeth, but the roots of the cryopreserved teeth were significantly shorter than those of the control teeth. Histological examination revealed root and periodontal ligament formations in all the transplanted groups. These results suggest that the transplantation of cryopreserved tooth germs facilitates subsequent root elongation and tooth eruption.

The Dual Effects of Reactive Oxygen Species on the Mandibular Alveolar Bone Formation in SOD1 Knockout Mice: Promotion or Inhibition.

The status of reactive oxygen species (ROS) correlates closely with the normal development of the oral and maxillofacial tissues. Oxidative stress caused by ROS accumulation not only affects the development of enamel and dentin but also causes pathological changes in periodontal tissues (periodontal ligament and alveolar bone) that surround the root of the tooth. Although previous studies have shown that ROS accumulation plays a pathologic role in some oral and maxillofacial tissues, the effects of ROS on alveolar bone development remain unclear. In this study, we focused on mandibular alveolar bone development of mice deficient in superoxide dismutase1 (SOD1). Analyses were performed using microcomputerized tomography (micro-CT), TRAP staining, immunohistochemical (IHC) staining, and enzyme-linked immunosorbent assay (ELISA). We found for the first time that slightly higher ROS in mandibular alveolar bone of SOD1(-/-) mice at early ages (2-4 months) caused a distinct enlargement in bone size and increased bone volume fraction (BV/TV), trabecular thickness (Tb.Th), and expression of alkaline phosphatase (ALP), Runt-related transcription factor 2 (Runx2), and osteopontin (OPN). With ROS accumulation to oxidative stress level, increased trabecular bone separation (Tb.Sp) and decreased expression of ALP, Runx2, and OPN were found in SOD1(-/-) mice at 6 months. Additionally, dosing with N-acetylcysteine (NAC) effectively mitigated bone loss and normalized expression of ALP, Runx2, and OPN. These results indicate that redox imbalance caused by SOD1 deficiency has dual effects (promotion or inhibition) on mandibular alveolar bone development, which is closely related to the concentration of ROS and the stage of growth. We present a valuable model here for investigating the effects of ROS on mandibular alveolar bone formation and highlight important roles of ROS in regulating tissue development and pathological states, illustrating the complexity of the redox signal.

A study on the morphologic change of palatal alveolar bone shape after intrusion and retraction of maxillary incisors.

The purpose of this study is to evaluate the changes in the palatal alveolar bone thickness and find the factors related to the resorption of the palatal alveolar bone caused by tooth movement after the maxillary incisors were retracted and intruded during orthodontic treatment. The study group comprised of 33 skeletal Class II malocclusion patients who underwent extraction for orthodontic treatment. Palatal alveolar bone thickness changes and resorption factors were identified and analyzed. The changes of maxillary central incisors and palatal alveolar bone thickness were measured, and the corresponding sample t test was performed using SPSS (IBM SPSS version 22). The amount of palatal alveolar bone resorption was measured and various parameters were analyzed to determine which factors affected it. Correlation analysis adopting the amount of palatal alveolar bone resorption as a dependent variable demonstrated that the SNB, mandibular plane angle, and the inclination of the maxillary central incisor were significantly correlated with before treatment. On the other hand, mandibular plane angle, angle of convexity, the inclination of the upper incisor, and the occlusal plane (UOP, POP) were significantly correlated with post-treatment. In addition, the variables related to palatal contour (PP to PAS, SN to PAS, palatal surface angle) and occlusal planes (UOP/POP) were significantly correlated with the difference in palatal bone resorption. During initial diagnosis, high angle class II with normal upper incisor inclination can be signs of high-risk factors. In addition, maintaining the occlusal plane during treatment helps to prevent palatal bone loss.

Dual role of phosphatidylserine and its receptors in osteoclastogenesis.

Fusion and apoptosis share a breakdown of the membrane phospholipids asymmetry, modes of which are largely unknown in osteoclastogenesis. Here, we investigated the externalization of phosphatidylserine (PS) and its receptors, and their biological functions in osteoclastogenesis. Strong immunoreactivities in vivo for the PS receptors TIM4, BAI1, and STAB2 were observed in the TRAP-positive multinucleated cells in the alveolar bone that was being remodeled around the developing dental follicles in rats. These receptors were significantly upregulated during M-CSF/RANKL-induced in vitro osteoclastogenesis using mouse bone marrow-derived cells. PS externalization in preosteoclasts was increased by the M-CSF/RANKL treatment. Multinucleation of preosteoclasts was markedly inhibited by antibodies against PS and its receptors. Among the investigated lipid transporter proteins, floppases (Abcb4, Abcc5, and Abcg1) were upregulated, whereas flippases (Atp11c and Atp8a1) downregulated during osteoclastogenesis. Preosteoclast fusion was markedly blocked by the ATPase inhibitor Na3VO4 and siRNAs against Abcc5 and Abcg1, revealing the importance of these lipid transporters in PS externalization. Further, the levels of Cd47 and Cd31, don't-eat-me signal inducers, were increased or sustained in the early phase of osteoclastogenesis, whereas those of AnnexinI and Mfg-e8, eat-me signals inducers, were increased in the late apoptotic phase. In addition, Z-VAD-FMK, a pan caspase inhibitor, had no effect on preosteoclast fusion in the early phase of osteoclastogenesis, whereas Abs against PS, TIM4, and BAI1 decreased osteoclast apoptosis during the late phase. These results suggest that PS externalization is essential for the whole process of osteoclastogenesis and share PS receptors and transporters in the early stage fusion and late stage apoptosis. Therefore, modulation of PS and its receptors could be a useful strategy to develop anti-bone resorptive agents.

Comparison of morphological quantitative characteristics of the newly formed alveolar bone after the application of demineralized bone matrix and cortical bone allografts / Comparación de las características morfológicas cuantitativas del hueso alveolar recién formado después de la aplicación de matriz ósea desmineralizada y aloinjertos de hueso cortical

The allografts were used to obtain sufficient alveolar bone tissue for proper dental implant placement. The objective of the present study was to evaluate the morphological and quantitative characteristics (cellular and collagen densities) of the newly formed alveolar bone with the application of cortical bone (CB) and demineralized bone matrix (DBM) allografts. Six samples of alveolar bone tissue from 5 patients (50 ± 6.3 years) were obtained after 6 months of application of the allografts and immediately before the placement of the dental implants. The samples were fixed (buffered formaldehyde, pH7.2), decalcified (EDTA 10 %) and histologically processed (HE and Picro-Sirius) for histologic analysis. Morphological analysis revealed presence of osteocytes and trabeculae in neoformed bone tissue near the allografts and absence of inflammatory and allergic cells; the remnants of CB were located mainly in the periphery of the bone tissue and the remnants of DBM were more incorporated into the tissue. Osteogenitor cells were observed around the remaining material. The cell density was not modified in newly formed bone tissue with the application of both allografts as compared to mature bone tissue. The density of the type I and III collagens present in the osteoids interspersed with the remainder of the materials showed a tendency to increase in the samples treated with DBM. It was concluded that by the histological characteristics observed both grafts were biocompatible, however the bone treated with DBM presented better incorporation and a tendency of increase of the collagen content in the remnant region of the allografts.

Los aloinjertos son utilizados para obtener tejido óseo alveolar apropiado para la colocación correcta del implante dental. El objetivo de este trabajo fue evaluar las características morfológicas y cuantitativas (densidades celulares y de colágeno) del hueso alveolar recién formado con la aplicación de aloinjertos de hueso cortical (CB) y matriz desmineralizada de hueso (DBM). Seis muestras de tejido óseo alveolar fueron obtenidas de 5 pacientes (50 ± 6,3 años) después de 6 meses de aplicación de los aloinjertos e inmediatamente antes de la colocación de los implantes dentales. Las muestras fueron fijadas (formaldehído tamponado, pH 7,2), descalcificadas (EDTA al 10%) y procesadas histológicamente (HE y Picro-Sirius) para el análisis histológico. El análisis morfológico reveló la presencia de osteocitos y trabéculas en el tejido óseo neoformado cerca de los aloinjertos y la ausencia de células inflamatorias y alérgicas; los remanentes de CB se ubicaron principalmente en la periferia del tejido óseo y los remanentes de DBM se incorporaron más en el tejido. Se observaron células osteogenitoras alrededor del material restante. La densidad celular no se modificó en el tejido óseo recién formado con la aplicación de ambos aloinjertos en comparación con el tejido óseo maduro. La densidad de los colágenos de tipo I y III presentes en los osteoides intercalados con el resto de los materiales mostró una tendencia a aumentar en las muestras tratadas con DBM. Se concluyó que, debido a las características histológicas observadas, ambos injertos fueron biocompatibles, sin embargo, el hueso tratado con DBM presentó una mejor incorporación y una tendencia al aumento del contenido de colágeno en la región remanente de los aloinjertos.

Growth-dependent phenotype in FasL-deficient mandibular/alveolar bone.

FASL (CD178) is known for its role in triggering apoptosis, mostly in relation with immune cells but additional functions have been reported more recently, including those in bone development. Examination of postnatal FasL-deficient mice (gld) showed an increased bone deposition in adult mice when compared with wild types. However, a different phenotype was observed prenatally, when the gld bone was underdeveloped. The aim of the following investigation was to evaluate this indication for an growth-dependent bone phenotype of gld mice and to search for the 'switch point'. This study focused on the mandibular/alveolar bone as an important structure for tooth anchorage. In vivo micro-computed tomography (CT) analysis was performed at different stages during the first month (6, 12 and 24 days) of postnatal bone development. In 6-day-old gld mice, a decrease in bone volume/tissue volume (BV/TV), trabecular thickness and trabecular number was revealed. In contrast, the 12-day-old gld mice showed an increased BV/TV and trabecular thickness in the alveolar bone. The same observation applied for bone status in 24-day-old gld mice. Therefore, changes in the bone phenotype occurred between day 6 and 12 of the postnatal development. The switch point is likely related to the changing proportion of bone cells at these stages of development, when the number of osteocytes increases. Indeed, the immunohistochemical analysis of FASL localized this protein in osteoblasts, whereas osteocytes were mostly negative at examined stages. The impact of FASL particularly on osteoblasts would agree with an earlier in vivo observed effect of FASL deficiency on expression of Mmp2, typical for osteoblasts, in the gld mandibular/alveolar bone. Notably, an age-dependent bone phenotype was reported in Mmp2-deficient mice.

New Bone Formation Using an Extracted Tooth as a Biomaterial: A Case Report with Histologic Evidence.

This case report aims to demonstrate the regenerative potential of particles obtained from a crushed extracted tooth. Following tooth removal, the clean root was ground and the dentin and cementum granules were grafted into a fresh extraction socket for a ridge preservation procedure. After 24 weeks, a successful implant placement was allowed. Tissue healing was evaluated by histologic and radiologic analysis. The volume of the ridge was preserved. Histologically, a dentin-bone complex was reported. New bone formation was evident, with an intimate contact between bone and both dentin/cementum. This novel procedure suggests the use of tooth particles as graft material.

Numerical investigations of bone remodelling around the mouse mandibular molar primordia.

The formation of the alveolar bone, which houses the dental primordia, and later the roots of tooth, may serve as a model to approach general questions of alveolar bone formation. In this respect, this study aimed to investigate the potential interactions between the alveolar bone formation and tooth eruption by using finite element (FE) methods, and to figure out whether the expanding tooth systems induce shear stresses that lead to alveolar bone formation. 3D geometric surface models were generated from the 3D histological data of the heads of mice (C57 Bl/6J) ranging from stages embryonic (E) to postnatal (P) stages E15 to P20 using the reconstruction software 3-Matic. Bone, dentin, enamel and dental follicle around the primordia were generated and converted into 3D FE models. Models were imported into the FE software package MSC.Marc/Mentat. As material parameters of embryonic dentine, pulp, enamel, dental follicle, and bony structures basically are unknown, these were varied from 1% to 100% of the corresponding known material parameters for humans and a sensitivity analysis was performed. Surface loads were applied to the outside surface of dental follicle ranging from 0.1 to 5.0N/mm2. The validity of the model was analysed by comparing the activity pattern of the alveolar bone as determined in the histological study with the loading pattern from the numerical analysis. The results show that when varying the surface loads, the distribution of shear stresses remained same, and while varying the material properties of the hard tissues, the location of highest shear stresses remained stable. Comparison of the histologically determined growth regions with the distribution of shear stresses computed in the numerical model showed a very close agreement. The results provide a strong proof to support Blechschmidt's hypothesis that the bone in general is created under the influence of shear forces.

Overexpression of αCGRP promotes osteogenesis of periodontal ligament cells by regulation of YAP signaling.

Human periodontal ligament cells (hPDLCs) are considered as an ideal cell type for periodontal tissue engineering as hPDLCs own mesenchymal stem cell-like properties. Additionally, it is suggested that α-calcitonin gene-related peptide (αCGRP) plays a pivotal role in the pathogenesis of periodontitis. However, the specific role of αCGRP on the regulation of alveolar bone regeneration which is essential for treatment of periodontitis remains unclear. In this study, lentiviral αCGRP expression vector was first transfected into hPDLCs. αCGRP expression and the osteogenesis-related gene (ALP, RUNX2, OCN, and BSP) expressions were detected. The results showed that expressions of osteogenic phenotypes were upregulated in αCGRP-transfected hPDLCs combined with an increased expression of Yes-associated protein (YAP), which is the key downstream effectors of Hippo pathway. Our observations suggest that αCGRP-mediated hPDLCs' osteogenesis might relate with the activity of YAP signaling. These observations may reflect intrinsic functions of αCGRP in hPDLCs' osteogenesis and its promising role in the treatment of bone deficiency in periodontal regeneration.

Efficacy of Alveolar Ridge Preservation after Maxillary Molar Extraction in Reducing Crestal Bone Resorption and Sinus Pneumatization: A Multicenter Prospective Case-Control Study.

AIM: To evaluate, with three-dimensional analysis, the effectiveness of alveolar ridge preservation (ARP) after maxillary molar extraction in reducing alveolar bone resorption and maxillary sinus pneumatization when compared to unassisted socket healing. METHODS: Patients were included in the study following inclusion criteria and underwent minimally traumatic maxillary molar extraction followed by ARP using synthetic nanohydroxyapatite (Fisiograft Bone, Ghimas, Italy) (test group) or unassisted socket healing (control group). Cone-beam computerized tomographies (CBCT) were performed immediately after tooth extraction (T0) and 6 months postoperatively (T1). CBCTs were superimposed by using a specific software (Amira, Thermo Fisher Scientific, USA) and the following items were analyzed in both groups: (i) postextractive maxillary sinus floor expansion in coronal direction and (ii) postextractive alveolar bone dimensional changes (both vertical and horizontal). All data were tested for normality and equality of variance and subsequently analyzed by independent samples T-test and Mann-Whitney test. RESULTS: Thirty patients were treated by three centers and twenty-six (test n=13; control n=13) were included in the final analysis. Mean sinus pneumatization at T1 was 0.69±0.48 mm in the test group and 1.04±0.67 mm in the control group (p=0.15). Mean vertical reduction of the alveolar bone at T1 was 1.62±0.49 mm in the test group and 2.01±0.84 mm in the control group (p=0.08). Mean horizontal resorption of crestal bone at T1 was 2.73±1.68 mm in test group and 3.63±2.24 mm in control group (p=0.24). CONCLUSIONS: It could be suggested that ARP performed after maxillary molar extraction may reduce the entity of sinus pneumatization and alveolar bone resorption, compared to unassisted socket healing. This technique could decrease the necessity of advanced regenerative procedures prior to dental implant placement in posterior maxilla.

ACVR1 is essential for periodontium development and promotes alveolar bone formation.

OBJECTIVE: To explore the role of a BMP type I receptor (ACVR1) in regulating periodontium development, Acvr1 was conditionally disrupted in Osterix-expressing cells. METHODS: Mandibles from both control (Acvr1 fx/+; Osterix-Cre (+)/(-)) and cKO (Acvr1 fx/-; Osterix-Cre (+)/(-)) mice at postnatal day 21 (PN21) were scanned by micro-CT, followed by decalcification and histological observations. Distributions and levels of differentiation markers of fibroblasts, osteoblasts and cementocytes in the periodontium were detected by immunohistochemical (IHC) staining. RESULTS: Micro-CT results showed that bone mass and bone mineral density of the alveolar bones in the cKO mice were lower than those in the controls. Histomorphometry within the alveolar bones revealed that the lower bone mass observed in the cKO mice was caused by increased numbers and resorption activities of osteoclasts. The markers for osteoblast differentiation, Col I and DMP1, were reduced and the signals of the RANKL/OPG ratio were increased in the alveolar bones of the cKO mice compared to those of the control mice. The periodontal ligament in the cKO mice exhibited disorganized collagen fibers with weaker signals of Col I and periostin. However, there was no difference in terms of the cellular cementum between the two groups. CONCLUSION: ACVR1 is essential for normal periodontium development. ACVR1 in the osteoblasts negatively regulates osteoclast differentiation in association with the RANKL/OPG axis and thus promotes alveolar bone formation.

Impact of obesity and aging on crestal alveolar bone height in mice.

Obesity and aging are associated with periodontitis, which represents a chronic inflammatory disease of the tooth-supporting tissues, i.e. the periodontium. However, if both risk factors also have a negative impact on crestal alveolar bone in a clinically healthy periodontium, has yet to be elucidated and was analyzed in this in-vivo study. Eight C57BL/6 mice were fed a normal diet during the entire study. Half of these mice were sacrificed at week 19 (group 1: younger lean mice), whereas the other half of the animals were sacrificed at week 25 (group 2: older lean mice). In addition, four mice were fed a high-fat diet until their sacrifice at week 19 (group 3: younger obese mice). Mandibles and maxillae were scanned by micro-computed tomography and, subsequently, the distance between the cementoenamel junction and alveolar bone crest (CEJ-ABC) at all molars was determined. Levels of interleukin-6, cyclooxygenase-2, visfatin and adiponectin in gingival samples were quantified by real-time PCR. For statistical analyses, the Mann-Whitney-U test was applied (p<0.05). As compared to lean mice, obese animals presented a significantly increased CEJ-ABC distance, i.e. reduced alveolar bone crest height, at week 19. The alveolar bone loss was mainly found at the first molars of the mandibles. In animals fed a normal diet, the alveolar bone crest height in the mandibles and maxillae was significantly lower in the older mice as compared to the younger animals. Furthermore, gingival cyclooxygenase-2 and visfatin expressions were higher in the obese versus lean mice and in the older versus younger mice. This in-vivo investigation shows that obesity and older age can result in reduced alveolar bone crest height and suggests that they represent risk factors even in a clinically healthy periodontium.

Relationship Between Orthodontic Force Applied by Monoblock and Salivary Levels of Alkaline Phosphatase and Lactate Dehydrogenase Enzymes.

AIM: The current study was aimed to determine the relationship between the orthodontic force applied by monobloc and the salivary level of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) enzymes, considering the time factor after insertion of the appliance and whether there is a correlation between these enzymes. MATERIALS AND METHODS: A sample of 28 growing patients requiring orthodontic treatment with myofunctional appliance (Monoblock) was taken for the current study with an age range 9 to 12 years,all patients had Angle's class II division 1 mal-occlusion with no or mild crowding, the sample was selected using simple random sampling. Only 16 subjects (10 males and 6 females) were included who follow certain inclusion criteria. Unstimulated saliva was collected from the patients before monoblock insertion, then 1 hour after insertion, followed by 14 days and 28 days. Salivary levels of ALP and LDH were measured using a spectrophotometer and compared with the base line. RESULTS: The results revealed that ALP and LDH levels increased with increasing time after monoblock insertion, and there was the statistically insignificant difference after 1-hour post-insertion for ALP enzyme level, but highly significant after 14 and 28 days. While for LDH level,there was the statistically significant difference after 1-hour post-insertion, but highly significant difference after 14 and 28 days post-insertion. In this regard to the relation between salivary ALP and LDH enzymes levels at different time intervals, showed that there were no significant correlations between the enzymes using Pearson's correlation test. CONCLUSION: The ALP and LDH salivary enzymes activity is affected by mechanical forces generated by monobloc activator and these enzymes activities can also be increased during the rapid growth phase of childhood such as late infancy and early puberty where the age of subjects was selected in the current study. CLINICAL SIGNIFICANCE: The determination of ALP and LDH salivary enzymes activities during the skeletal maturity is crucial for the success of myofunctional monobloc treatment; therefore, saliva can be used as a noninvasive diagnostic tool for determination of chemical biomarkers for detection of bone remodeling process during myofunctional monoblock treatment Keywords: Alkaline phosphatase (ALP), Lactate dehydrogenase (LDH), Monoblock, Orthodontic force, Salivary levels.

Modified Activation Technique for Nasal Stent of Nasoalveolar Molding Appliance for Columellar Lengthening in Bilateral Cleft Lip/Palate.

Bilateral cleft lip/cleft palate is associated with nasal deformities typified by a short columella. The presurgical nasoalveolar molding (NAM) therapy approach includes reduction of the size of the intraoral alveolar cleft as well as positioning of the surrounding deformed soft tissues and cartilages. In a bilateral cleft patient, NAM, along with columellar elongation, eliminates the need for columellar lengthening surgery. Thus the frequent surgical intervention to achieve the desired esthetic results can be avoided. This article proposes a modified activation technique of the nasal stent for a NAM appliance for columellar lengthening in bilateral cleft lip/palate patients. The design highlights relining of the columellar portion of the nasal stent and the wire-bending of the nasal stent to achieve desirable results within the limited span of plasticity of the nasal cartilages. With this technique the vertical taping of the premaxilla to the oral plate can be avoided.

Evaluating of Platelet-Rich Fibrin in the Treatment of Alveolar Cleft With Iliac Bone Graft By Means of Volumetric Analysis.

The purpose of this study was to evaluate the efficiency of platelet-rich fibrin usage in the treatment of alveolar cleft with iliac bone graft by means of volumetric analysis. In this study, 22 patients with alveolar clefts-including 13 unilateral and 9 bilateral-were treated with anterior iliac crest bone grafts. Patients were divided into 2 groups as control (group A) and platelet-rich fibrin (group B) groups. Cone beam computed tomography (CBCT) scans were obtained preoperatively and 6 months postoperatively. Three-dimensional reconstructions of CBCT images were created by using Mimics software. Preoperative alveolar cleft volume and postoperative newly formed bone volume were assessed volumetrically. The percentages of preoperative alveolar cleft volume ranged from 0.51 to 2.04 cm, with a mean volume of 0.98 ±â€Š0.33 cm. The percentages of newly formed bone in group B ranged from 50.70% to 80.09%, with a mean percentage of 68.21 ±â€Š10.80%. In Group A, the percentages of bone formation ranged from 47.02% to 79.23%, with a mean percentage of 64.62 ±â€Š9.49%. Platelet-rich fibrin can be used in the treatment of alveolar cleft with corticocancellous bone graft harvested from the anterior iliac crest, but in this study, there was no statistically significant difference between the groups for postoperative newly formed bone volume (P > 0.05).

Craniofacial height in relation to cross-sectional maxillary and mandibular morphology.

BACKGROUND: In order to gain a better understanding of how growth of the alveolar bone is linked to the vertical development of the face, the purpose of this study was to investigate if there is an association between the cross-sectional morphology of the maxillary and mandibular bodies with the craniofacial height, using images from cone beam computed tomography (CBCT). METHODS: From 450 pre-treatment CBCT scans, 180 were selected to be included in the study. Lateral head images were generated from the CBCT scans and were used to categorise subjects into three groups based on their vertical craniofacial height. Cross-sectional images from CBCT volumes were reformatted of the maxillary and mandibular bodies at five locations in the maxilla and five in the mandible. Each image was measured at one height and two width measurements. Statistical analysis performed was the one-way analysis of variance with a Tukey post hoc test. A significance level of 5% was used in all comparisons. RESULTS: Patients with large vertical craniofacial height had a significantly higher cross-sectional area both in the maxilla and in the mandible. In the same group, the cross-sectional area was significantly thinner in the mandible compared with the other two groups, especially in the anterior region. CONCLUSIONS: This study further highlights the close relationship between craniofacial height and alveolar bone dimensions and contributes with important knowledge for planning and follow-up of comprehensive dental- and orthodontic treatments.

Dentoalveolar Effects of Early Orthodontic Treatment in Patients With Cleft Lip and Palate.

No agreement exists on the most appropriate timing of orthodontic treatment in patients with cleft lip and palate. The aim of this study is to investigate the effect of early orthodontic treatment on development of the dental arches and alveolar bone.A dental casts analysis was performed on 28 children with cleft lip and palate before orthodontic treatment (T0; mean age, 6.5 ±â€Š1.7) and at the end of active treatment (T1; mean age, 9.2 ±â€Š2.1 years). The considered variables were: intercanine and intermolar distances; dental arch relationships, evaluated according to the modified Huddart/Bodenham system.The study group was divided into 2 samples according to the age at T0: Group A (age < 6 years) and Group B (age ≥ 6 years). A statistical comparison of the treatment effects between the 2 samples was performed.Patients in Group A exhibited a greater increase of intercanine distance (8 mm versus 2.7 mm; P<0.001), intermolar distance (7.2 mm versus 5 mm; P = 0.06), and Huddart/Bodenham score (7.1 versus 3; P < 0.05) when compared with patients in Group B.Early orthodontic treatment strongly improved the dental arch relationship, since subjects starting the therapy before the age of 6 had a better response in terms of anterior maxillary expansion.

Effects of vascular formation during alveolar bone process morphogenesis in mice.

The alveolar bone process is the thickened ridge of bone that bears the teeth and is known to have dynamic functional interactions with surrounding tissues. However, the detailed morphological changes that occur during alveolar bone process development and the underlying molecular mechanisms behind this morphogenesis have not been elucidated. In this study, we examined the detailed morphological changes of the alveolar bone process during mouse development using HE and MTC staining. In addition, we evaluated the precise localization pattern of various signaling molecules involved in blood vessel formation including CD31, α-SMA, VEGF, periostin, and TGF-ß. Innervation of the alveolar bone process was examined following injection of the nerve terminal dye AM1-43. The morphological and immunohistochemical data suggested that there is an intimate relationship between alveolar bone process development and blood vessel formation. To more closely examine the role of blood vessels in alveolar bone process formation, we microinjected mice with a clinically available anti-VEGF antibody, bevacizumab, at PN5 and analyzed the effects 5 days later. Compared to the control animals, anti-VEGF treated animals showed a disruption of the integration of bony tissues to form the alveolar bone process structures, which should contain the periodontal ligaments. Based on these data, we conclude that specific morphogenesis of the alveolar bone process is closely associated with blood vessel formation.

TLR2 Signaling Pathway in Alveolar Bone Osteogenesis Induced by Aloe vera and Xenograft (XCB)

Abstract The aim of this study was to find the role of TLR2 signaling pathway in reducing osteoclast activity and promoting osteoblast growth by inducing a combination of Aloe vera and cancellous bovine xenograft (XCB) into dental extraction socket. Forty-eight Cavia cobayas were used. They were divided into eight groups (n=6). For control group, their mandibular incisors were extracted and filled with PEG. For treatment groups, they were extracted and filled with XCB, Aloe vera and the combination of Aloe vera and XCB. The first four groups were sacrificed after 7 days and the other groups after 30 days. Immunohistochemistry and histopathology examination were conducted to examine TLR2, TNFa, OPG, collagen-1, and the osteoblast and osteoclast expressions. The expressions of TLR2, OPG and Collagen-1, as well as the number of osteoblast were increased. Meanwhile, the expressions of TNFa and osteoclast were decreased. The study finding was that TLR2 signaling pathway influenced alveolar bone osteogenesis process by reducing osteoclast activity and stimulating osteoblast growth induced by the combination of Aloe vera and XCB.

Resumo O objetivo deste estudo foi investigar o papel da via de sinalização de TLR2 na redução da atividade osteoclástica e na promoção do crescimento de osteoblastos, induzindo uma combinação de Aloe vera e enxerto de osso esponjoso bovino (EOEB) em alvéolo de extração dentária. Quarenta e oito Cavia cobayas foram utilizados e divididos em 8 grupos (n = 6). Para o grupo de controle, seus incisivos mandibulares foram extraídos e preenchidos com polietilenoglicol (PEG). Para grupos de tratamento, os dentes foram extraídos e preenchidos com EOEB, Aloe vera e a combinação de Aloe vera e EOEB. Os primeiros quatro grupos foram sacrificados após 7 dias e os outros grupos após 30 dias. As análises de imunohistoquímica e histopatologia foram realizada para examinar TLR2, TNFa OPG, colágeno-1 e as expressões de osteoblastos e osteoclastos. Houve maior expressão de TLR2, FGF2, OPG e colágeno-1, bem como maior número de osteoblastos. Enquanto isso, a expressão de TNFa e osteoclastos estava diminuída. O principal achado do estudo foi que a via de sinalização de TLR2 influenciou o processo de osteogênese do osso alveolar, reduzindo a atividade dos osteoclastos e estimulando o crescimento de osteoblastos induzido pela combinação de Aloe vera e EOEB.

Age estimation from structural changes of teeth and buccal alveolar bone level.

Forensic odontology plays a vital role in the identification and age estimation of unknown deceased individuals. The purpose of this study is to estimate the chronological age from Cone-Beam Computed Tomography (CBCT) images by measuring the buccal alveolar bone level (ABL) to the cemento-enamel junction and to investigate the possibility of employing the age-related structural changes of teeth as studied by Gustafson. In addition, this study will determine the forensic reliability of employing CBCT images as a technique for dental age estimation. A total of 284 CBCT images of Malays and Chinese patients (150 females and 134 males), aged from 20 years and above were selected, measured and stages of age-related changes were recorded using the i-CAT Vision software. Lower first premolars of both left and right side of the jaw were chosen and the characteristics described by Gustafson, namely attrition, secondary dentine formation and periodontal recession were evaluated. Linear regression analysis was performed for the buccal bone level and the R values obtained were 0.85 and 0.82 for left and right side respectively. Gustafson's characteristics were analysed using multiple regression analysis with chronological age as the dependent variable. The results of the analysis showed R values ranged from 0.44 to 0.62. Therefore it can be safely concluded that the buccal bone level highly correlated with the chronological age and is consequently the most suitable age-related characteristic for forensic age estimation.