Biological apatites composing the inorganic part of many hard tissues have many characteristics differing from mineral and/or synthetic apatites. Before the modern precise analytical technique and methods were introduced to the hard tissue study, the non-stoichiometry of biological apatites was a problem, and the carbonated apatite in bone and tooth was sometimes mistaken for a mixture of calcium carbonates, calcium phosphates, and calcium oxides. Apatite is a mineral group which makes wide ranged solid-solution systems. Although hydroxyapatite is the most stable phase in the mimetic conditions to body system among the calcium phosphates, it can not be successfully precipitated under laboratory conditions. Therefore, some mechanisms have been proposed to crystallize biological apatite in the body conditions. In this review, the history of unveiling the nature of biological apatites is described from a crystallographic viewpoint, and bio-medical applications of calcium phosphates are introduced.

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The objective of the study was to discuss the biocompatibility of VEGF-silk fibroin-chitosan (VEGF-SF-CS) three-dimensional scaffolds in order to offer an ideal scaffold for bone tissue engineering. Bone marrow derived mesenchymal stem cells (BMSCs) were seeded on the VEGF-SF-CS three-dimensional scaffolds and silk fibroin-chitosan (SF-CS) three-dimensional scaffolds. On VEGF-SF-CS and SF-CS three-dimensional scaffolds, the cell adhesion rate was increased as time went on. Scanning electron microscopy: The cells grew actively and had normal multiple fissions, granular and filamentous substrates could be seen around the cells, and cell microfilaments were closely connected with the scaffolds. The cells could not only show attached growth on surfaces of the scaffolds, but could also extend into the scaffolds. CCK-8 and ALP analysis proved that the vascular endothelial growth factor (VEGF) could significantly promote BMSCs growth and proliferation in the SF-CS scaffolds; however, the enhancement of BMSCs cell proliferation and activity by VEGF is dependent on time. Thus, VEGF-SF-CS composite scaffolds represent a promising new type of scaffold for bone tissue engineering.

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During embryonic palatogenesis, development of the secondary palate represents a particularly complex process involving the formation, elevation and midline fusion of the palatal shelves. In recent years, it has been shown that the specific expression of type I collagen and periostin in the palatal aponeurosis results in formation of the soft palate. However, few reports have examined soft palate development in relation to the skeletal muscles connected to the palatal aponeurosis. Thus, in the present study, focusing on the tensor veli palatine muscle and surrounding tissues in embryonic mice, we performed immunohistochemical examination and real-time PCR (RT-PCR) in order to investigate the expression of desmin and vimentin. Low levels of desmin expression were observed in the tensor veli palatine muscle on embryonic day (ED) 12.5, with the levels of expression increasing from ED 13.5 to 15.5. In addition at ED 12.5, desmin was observed to accumulate in the area of the myotendinous junction, and this accumulation remained unchanged up to ED 15.5. Meanwhile, vimentin expression was observed in the tensor veli palatine muscle and surrounding tissue at ED 12.5, and this level of expression did not change up to ED 15.5. Strong expression of vimentin was observed at ED 14.5 only in the medial edge epithelium (MEE). Both immunohistochemical examination and RT-PCR yielded consistent results. In the present study, we found that desmin accumulates in the vicinity of the myotendinous junction at ED 12.5, which is prior to initiation of swallowing movement. From this, we are able to conclude that this accumulation of desmin is caused by factors other than mechanical stress resulting from initial muscle contraction. Furthermore, the elevated expression of vimentin during embryogenesis, and that of desmin after differentiation, suggest that there may be some interaction between the two intermediate filaments in determining muscle cell differentiation.

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The influence of high glucose on proliferation and expression of correlation factors including TNF related apoptosis inducing ligand (TRAIL), osteoprotegerin (OPG) and osteoprotegerin ligand (OPGL) of MG63 osteoblasts was detected in the present study. The relationship between the high concentration blood glucose and the physiological functions of human osteoblasts was studied. Then the pathogenesis of diabetes mellitus with chronic periodontitis was discussed. MG63 cells were cultured in different concentrations (5.5 mmol/l, 8 mmol/l, 11 mmol/l, 20 mmol/l, 30 mmol/l) medium for 24 hours. Cell proliferation was detected by MTT measurement. Flow cytometry was used to detect cell cycles. The mRNA expressions of TRAIL, OPG, and OPGL were detected by reverse transcription polymerase chain reaction (RT-PCR). The results showed that a low concentration of glucose has no significant influence on the proliferation of MG63 cells and other biological activity. With the increase of glucose concentration, the proliferation of MG63 cells was inhibited. The percentage of G1 phase cells was increased, the proportion of S phase kept unchanged and the percentage of G2 phase cells was decreased. With the increase of glucose concentration, the mRNA expressions of TRAIL and OPGL of MG63 cells showed an increasing trend while OPG showed an opposite trend. In conclusion, high glucose can inhibit the proliferation of MG63 and lead to the increasing mRNA expression of TRAIL and OPGL of human osteoblasts. However, the mRNA expression of OPG of human osteoblasts was decreased.

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The aim of this study was to investigate the effects of local administration of fluvastatin-gelatin complex on the healing of bone defects in low-turnover osteoporosis mice. Gelatin was used as a carrier of the fluvastatin. A fluvastatin-gelatin complex solution was created by dissolving each concentration of fluvastatin in a 75mg/mL gelatin solution. The gelatin solution was mixed with air, then lyophilized for 1 day and cross-linked by dry heating to make a fluvastatin-gelatin complex sponge. After crosslinking, the complex sponge was cut into pieces 1 mm diameter × 1 mm high to fit the bone defect area. The amount of fluvastatin in the sponge was adjusted to control (0 nmol), 0.1 nmol, 0.2 nmol, and 0.4 nmol. Using 20-week-old low-turnover osteoporosis model mice (SAMP6) and normal model mice (SAMR1), cylindrical and bone defects were made in sites 1.0 mm in diameter and depth, 1 mm of 3 mm from both sides of the distal end of the femur. The complex sponge was then inserted into each site, and the wound was closed. Radiographic analysis and histologic examinations were then performed. In SAMP6, the bone volumes of the bone defect areas in the 0.1nmol and 0.2nmol groups were significantly higher compared with those of the control and 0.4nmol groups at 14 and 21 days. Histological observation showed that the volume of newly formed bone increased in the 0.1nmol and 0.2nmol groups compared to those in the control and 0.4nmol groups at 14 and 21 days. The bone volumes of newly formed bone in SAMR1 were higher than were those in SAMP6, and the optimum concentration of fluvastatin was different between SAMP6 and SAMR1. The present study suggests that local administration of a fluvastatin-gelatin complex sponge provides improvement in bone healing in low-turnover osteoporosis.

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In order to establish standard normsfor the Pakistani population, we investigated the geomorphometrics of tooth size and arch dimension using a conventional digital caliper (DC) and a digital stereomicroscope (SM). The sample consisted of 128 subjects ranging in age from 18 to 24 years. A total of 44,155 variables were measured. Dental models of each subject for maxillary and mandibular arches were scanned via Hirox digital stereomicroscope for the fabrication of the digital models, and the geomorphometrics of tooth size and arch dimensions were measured via SM scanned digital models. All the measurements were also carried out via DC on plaster dental models. Sex differences and changes associated with methods were assessed, and interrelationships between different variables were explored within the study group. For the data obtained by DC and SM techniques, the men had significantly larger arch dimensions and geomorphometrics of tooth size than the women did. There were no significant disparities observed between the techniques. The developed norms for the mesiodistal, buccolingual, diagonal tooth sizes and arch dimension had significantly greater values for males in relation to females (*pd” 0.05 to ***pd” 0.001). This study has established a new reference database of tooth size and arch dimensions via both DC and digital SM for first time on Pakistani population. These norms will be helpful for clinical treatment planning in dentistry. Contemporaneously, the norms will be of great value to forensic dentists and dental anthropologists for making comparisons within and between different populations.

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This study investigates the effects of the Wnt signaling pathway on the osteogenic differentiation of human adipose-derived stem cells (hASCs) under tensile stress. hASCs cultured in vitro were divided into 4 groups: Group A, hASCs; Group B, Wnt5a RNAi-treated hASCs; Group C, hASCs under tensile stress; and Group D, Wnt5a RNAi-treated hASCs under tensile stress. Five days after treatment, the genes associated with the Wnt/β-catenin and Wnt/Ca²⁺ pathways were analyzed in all groups by real-time RT-PCR; the Wnt10b, Wnt5a, RUNX2 and SPP1 proteins were analyzed by western blot analysis. Compared with the expression in Groups A and B, all the genes and proteins in Groups C and D had higher expression, except for Wnt5ain Group D. Compared with Group C, Wnt5a, RhoA ,RUNX2 and ALPL had lower expression in Group D, but the markers associated with Wnt/β-catenin had higher expression. The results suggest that tensile stress can promote maturation and osteogenic differentiation in hASCs and also activate the Wnt/β-catenin and Wnt/Ca²⁺ pathways. The Wnt/Ca²⁺ pathway may have the potential to inhibit the Wnt/β-catenin pathway. Wnt5a knock down seemed to increase the expression of the Wnt/β-catenin pathway, which is activated by Wnt10b.

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Oral lichen planus (OLP) can undergo malignant transformation and become squamous cell carcinoma (SCC). Oral infection with human papillomavirus (HPV) is associated with a significant risk of developing oral cancer. Although HPV DNA is detected more often in OLP tissue than in normal oral mucosa, there is as yet no firm evidence that HPV is a causative factor of malignant transformation in OLP. The objective of the present investigation was to assess HPV-genotype distribution in OLPs of Japanese patients and additionally to clarify the relationship between malignant transformation in OLP and HPV infection using PCR, in situ hybridization, and immunohistochemistry. DNA of 200 formalin-fixed, paraffin-embedded biopsy and surgical specimens of OLP was extracted. HPV infection was first detected by PCR using consensus HPV primers. Positive PCR samples were then further analyzed by PCR using HPV type-specific primers (HPV-6, -11, -16, -18 and -33). Eighty-three samples (41.5 %) out of the total 200 OLP specimens analyzed were HPV positive. In the HPV type-specific PCR assay, the most frequent type of HPV was HPV-16 (25.5 %), which is a high-risk type of HPV that is associated with malignant disorders and is often detected in SCC. The highest HPV-16 positive rate was obtained for the erosive type of OLP (28.3 %). Positive staining for HPV DNA by in situ hybridization was observed in the nuclei of cells in all layers of the epithelium in all HPV PCR positive samples. Immunohistochemically, nuclei of cells in the upper layer of the epithelium in all HPV PCR positive samples stained positive for the anti-HPV antibody. These results indicated that HPV-16 was often present in OLP of Japanese patients, especially in the erosive type of OLP, and suggested that HPV infection is a risk factor for malignant transformation in OLP lesions.

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Low-intensity pulsed ultrasound (LIPUS) is known to promote bone defect healing. The frequency of the LIPUS is known to influence directivity and depth of penetration, but the differences on bone healing remains unknown. This study was to investigate the effect of LIPUS with different frequencies on bone defect healing. Bone defects of 1.6 mm in diameter were created in femurs of ten-week-old male Long-Evans rats (n=36). Experimetal groups were exposed LIPUS (intensity: 30 mW/cm2, burst width: 200 μs, time: 15 min/day) and divided into a low frequency (LF, 1.5 MHz) group and a high frequency (HF, 3.0 MHz) group. Non-exposed LIPUS group were used as control. After 3, 5, 7, and 10 days, femurs were removed and radiological, histomorphological and molecular biological evaluations were conducted. Micro-CT images showed that the depression in cortical bone was reduced in LF and HF groups. 3D bone morphological analysis at 10 days revealed that LIPUS increased cortical bone volume / tissue volume (BV/TV) and decreased BV/TV in the lower layer of cancellous bone (P<0.05). Histomorphologically, clot retraction was seen in the both LIPUS groups but not in the control group at 3 days. These effects were observed at a deeper layer in the LF group than in the HF group. No significant difference in osteopontin (OPN) gene expression was observed. However, osteocalcin (OCN) gene expression was significantly elevated in the HF group relative to the control group at 10 days (P<0.05). Immunohistochemical staining revealed that newly formed bone exhibited a positive reaction to OPN and OCN in both LIPUS groups. Healing of the bone defect area was noted in both LIPUS groups, but there was no clear difference in histomorphology between the LF and HF groups. LIPUS frequencies of 1.5 MHz and 3.0 MHz promote increased cortical bone mass and remodeling of cancellous bone in rat femurs with bone defects.

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The purpose of this study was to examine the potential application of a tetrapod-shaped artificial bone, Tetrabone (TB), along with collagen, in bone regeneration. Nine-week-old male Wistar rats (n = 60) were used. An 8 mm-diameter defect was filled with TB, collagen, or a combination mixture of TB and collagen, and left untreated in the control group. The results showed higher volumes of the newly formed bones in the combination group than in the TB group or control group at each time point by micro-CT analysis (P < 0.05). The TB group showed bone formation that extended from the existing bone. In contrast, the collagen group showed disseminated bone formation in the defect. Runx2- and TGF-β-positive cells were identified at collagen and TB surfaces. The bone formation of the combination group had characteristics of both TB and collagen groups. The combination group showed bone formation from the existing bone edge and in the entire part of the defect. Thus, the combinatorial use of TB and collagen would be an effective strategy for the treatment of bone defect.

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The temporomandibular joint (TMJ) disc plays an important role in mandibular motion. Once the TMJ disc perforates, spontaneous recovery does not occur. The aim of this study was to induce regeneration of the TMJ disc through an in situ tissue engineering method. Japanese white rabbits weighing 2.5-3.0 kg were used in this study. The TMJ was surgically exposed and a round full-thickness perforation of diameter 1.6 mm was made in the center of the disc. Animals were divided into A and B groups. In group A, a collagen sponge scaffold (1.6 mm in diameter with a height of 1.0 mm) was placed in the perforation. In group B, a collagen sponge scaffold mixed with autologous bone marrow was placed in the perforation. In both groups, a control perforation was made on the opposite side and left unfilled. The TMJ discs with surrounding tissues were collected 2, 4 and 8 weeks after surgery and were subjected to histological evaluation. In group A, after 4 weeks the size of perforation was reduced, but after 8 weeks, the perforation had still not completely closed. In group B, after 2 weeks, regeneration of the disc was seen and the site of the perforation was completely filled by new connective tissue. In the controls, after 8 weeks, the size of perforation was reduced, but it had not completely closed. The results indicate that collagen sponge scaffold with autologous bone marrow may have the potential to induce regeneration of a damaged TMJ disc.

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Osteosynthetic bone fixation devices made from composites of uncalcined and unsintered hydroxyapatite (u-HA) particles and poly-L-lactide (PLLA) are widely adopted for clinical use because of their bioresorbability and osteoconductive properties. However, how the plate systems constituting these devices change during long-term use in vivo is unknown. In this study, we present cases of two patients fitted with u-HA/PLLA devices for >5 years after surgery and evaluate the resorption process on the basis of the residual versus the resorbed material. In both cases, the majority of the degraded plates and screws had been replaced by bone. In post-operative three-dimensional (3D) CT imaging, plate and screws were maintained until two years after surgery, and then they were degraded and replaced to bone in 4-6 years after surgery. Examination of the aggregation of hydroxyapatite and decrease in molecular weight suggested that the residual material was in the final stages of resorption. The plate system examined demonstrated stable degradation without foreign body reactions in vivo. Although complete resorption is a lengthy process, it is possible to follow its progress using CT.

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The normal position of maxillary sinus is imperative in the field of oral surgery, endodontics and orthodontics. In oral surgery, intermaxillary fixation (IMF) screws need to be positioned away from the maxillary sinus. The apices of the posterior maxillary teeth lie in close proximity to the sinus. This study aimed to correlate the position of the maxillary sinus to the alveolar crest as imaged by Cone Beam Computerized Tomography (CBCT) in a relatively larger sample of a particular race (Malaysian Malay). The CBCT volumetric data of 98 patients was used. Malay patients who had a complete set of dentition except third molars were selected for this study. A straight line was drawn from the alveolar crest to the sinus floor. The relationship between the maxillary sinus and the alveolar crest was evaluated by using the images from the sagittal view. The paired t test was used to compare the differences in the right and left quadrants. Sinus height between 2^nd and 1^st molar and 1^st molar and 2^nd molar shows significant difference (P<0.05) when compared between right and left quadrants. The 3D sinus height knowledge is imperative for multidiscipline purpose.

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