Journal of Hard Tissue Biology Vol. 26(2017) No. 3

Considering existing similarities of bones and teeth formation and following mineralization, the aim of the study was to evaluate biochemical bone metabolism markers in growing Polish Merino sheep and their relationships with morphometric, densitometric and mechanical properties of deciduous mandibular teeth and mandible. Blood samples were collected from 28-day and 150-day-old sheep to determine serum concentrations of insulin-like growth factor I (IGF-I), bone-specific alkaline phosphatase (BAP), osteocalcin, C-terminal propeptide of type I procollagen (CICP), C-terminal telopeptides of type I collagen (CTX-I) and C-terminal telopeptides of type II collagen (CTX-II). Bone and tooth samples were collected from 150-day-old sheep and were evaluated morphologically, densitometrically and mechanically. Serum concentrations of BAP, OC and CTX-II were significantly lower in 150-day-old sheep when compared to the measurements performed 4 months earlier (P < 0.01). Negative correlation between CTX-I and OC concentrations in 150-day-old sheep was stated (P < 0.05). Majority of the significant correlations between tooth properties and serum biochemical bone metabolism indices were found in 28-day-old sheep indicating more intensive odontogenesis process of deciduous teeth than 4 months later. Positive correlations between morphological and densitometric properties of mandible and serum CICP dominated in 28-day-old sheep, while 4 months later CTX-II was the only one marker positively correlated with morphological, densitometric and mechanical properties of mandible (P < 0.05). Evaluation of bone and cartilage metabolism markers in serum may be utilized in further studies on regulation of dental and skeletal metabolism with environmental, physiological, pharmacological, nutritional and toxicological factors influencing mineralized tissue metabolism.

Various biochemical researches have been conducted for bone defects in the head, neck and maxillofacial region. Guided Bone Regeneration (GBR), which does not require any graft material, has focused on. However, GBR has been considered to be difficult to be used for critical-sized bone defects. In recent years, it has been made possible to make three-dimensional (3D) structures by additive manufacturing, which titanium (Ti) powders are successively melted and solidified (Selective Laser Melting technique; SLM). Using this technique, Ti devices in various shapes have been made available for practical use. In this study, we used Ti meshes prepared by SLM in a rat calvaria bone defect model, and examined the bone formation process at the bone defect site. Observations of undecalcified ground samples showed that the amount of new bone formation in 2 weeks postoperatively in the SLM-prepared Ti mesh group was significantly greater than that in the control group. This result suggests that SLM-prepared Ti meshes have a high osteogenic potential in vivo.

In the present study, experimental periodontitis was induced by ligature in Wistar rats that were not on high-fat or high-carbohydrate diet. The metabolic and inflammatory parameters in the serum were examined in order to assess the effect of periodontitis-induced inflammation on metabolic syndrome in individual without the genetic and dietary risk factors. Ligature-induced experimental periodontitis increased monocyte chemoattractant protein-1 and triglyceride levels in the serum, as well as homeostasis model assessment of insulin resistance, based on the concentration of serum glucose and insulin in Wistar rats. Furthermore, elevated triglyceride levels and altered expression of genes associated with glucose and lipid metabolism were also observed in the liver of rats with experimental periodontitis, suggesting that the onset of periodontitis induced metabolic syndrome independent of genetic and dietary risk factors.

The cervical lymph node metastasis of Oral Squamous Cell Carcinoma (OSCC) has been considered to be the main causes of death. The aim of our study was to clarify the expression pattern of ABCG2 and podoplanin in OSCC tissues and corresponding cervical lymph node, and evaluate the diagnostic value of ABCG2 and podoplanin in OSCC for tumorigenesis, histological stage and clinical prognosis. ABCG2 showed a mixed membranous and cytoplasmic pattern of staining in specific regions of stratum corneum and the center of well differentiated cancer nest, while only expressed in cytoplasm of poorly differentiated tumor nests. Podoplanin showed strong staining in LV endothelia, the periphery of well differentiated cancer nests, and tumor stromal fibroblasts surrounding tumor nests. The expression of ABCG2, especially cytoplasmic ABCG2, and podoplanin protein showed significantly higher tendency to lymph node metastasis (P<0.05). Meanwhile, podoplanin positive rate increased with the decreasing degree of histological differentiation (P<0.05). ABCG2 and podoplanin expression pattern is correlated with lymph node metastasis of OSCC. This result suggested that cytoplasmic ABCG2 with podoplanin have clinical potential in reliable molecule diagonsis for OSCC.

The purpose of this study was to assess the level of accuracy that can be achieved in patients undergoing orbital reconstruction for orbital floor defect accompanied by midfacial fracture using an unsintered hydroxyapatite particles/poly-L-lactide composite plate system with and without the use of intraoperative navigation. Eight consecutive patients treated using the u-HA/PLLA mesh plate system between 2014 and 2016 were included in this retrospective study. We analyzed the clinical and radiological data of these patients with orbital floor defect and midfacial fracture extending to the orbit. We examined the patients’ postoperative healing status, including visual activity, diplopia, and enophthalmos. The overall volume of the orbit was calculated in cubic millimeters and was compared between the reconstructed orbit and the uninjured orbit for with and without the use of navigation groups. No patients complained of visual problems, and no further treatment was required postoperatively. Except for one patient with persistence of slight supraversion diplopia in the group without navigation, all the preoperative diplopia symptoms postoperatively improved, and none of the patients complained of problems in daily living. There was a significant difference (p < 0.05) in the mean reconstructed orbital volume accuracy between with and without navigation. In conclusion, complex orbital reconstruction using optimal bioactive/resorbable material with intraoperative navigation is an accurate and reliable method of reconstruction.

We examined the subcutaneous tissue reactions in rats to bioabsorbable suture thread using histopathological methods. Using Wister rats, Vicryl^®, a bioabsorbable suture thread, was embedded into the subcutaneous tissue and histopathological examination was carried out after 4 weeks. Cholesterin crystals were used for the control. Furthermore, immunohistochemistry for CD68 was done. Histopathological examination showed proliferation of granulation tissues in both experimental and control groups. The majority of cells in the granulation tissues were macrophages and giant cells. Fibroblasts were also observed in the proliferating granulation tissues surrounding the embedded bioabsorbable suture thread. Immunohistochemistry revealed that macrophages and giant cells were positive to CD68. The results suggest that the embedded bioabsorbable suture thread is not only fabricated to undergo absorption but also for phagocytosis by macrophages and foreign body giant cells.

Calcium hydroxide is mainly used for dental pulp capping and it is thought that it induces hard tissue formation far better than other materials. Experimentally verifying this fact, Nishikawa et al revealed that bone-like dentin corresponding to tertiary dentin is rapidly formed when calcium hydroxide is applied directly to the pulp. Utilizing the same experimental system, histochemical study of the newly formed hard tissue (reparative dentin) was carried out and the results thereof were reported. Thick and irregular reparative dentin was formed in the pulp cavity and partial narrowing of the root canal was observed in m-CT. Histopathologically, the irregular reparative dentin increased its thickness obliterating the root canal having a different Azan staining of aniline blue compared to primary dentin. Numerous cellular inclusion bodies were also trapped inside the thick dentin. Furthermore, with Schmorl’s thionine picric acid staining, thick reparative dentin was noted around the pulp cavity and dentin. The dentin was densely stained with picric acid with different staining ability from the surrounding dentin. In addition, it was clearly confirmed that many cells were trapped in reparative dentin. The results of the experiment suggest that the characteristics of the newly formed reparative dentin is comparable to tertiary dentin.

Dental implants are the best choice to replace missing teeth. However, to place an implant sufficient bone around the implant is needed. Sometimes, the height or the thickness of the natural bone where an implant should be placed is not sufficient. For such cases bone grafting is recommended. In order to succeed bone grafting, it is necessary to achieve a good stability of the graft, enough vascularisation, and a tension free closure of the flap. The use of screwed bone block may solve the stability problem. However, it is hard to shape it, time consuming and it oblige the surgeon to open a second site to harvest the bone. Till today it is recommended to use particles in grafting for small bone defects, because the particles are not stable and it is hard to keep it in place under the chewing forces and movements. The Mineralized Plasmatic Matrix solves this problem, and opens a new age for the use of particles grafting, because by using the fibrin network, it gathers all the particles and offers a very good stability for the graft.

The objectives are to investigate the association between dental caries and H. pylori, the association between dental caries and smoking among Saudi students, and to investigate the association between smoking and H. pylori among students with dental caries. The present cross sectional study included 120 male students from Aljouf University. Participating students were clinically examined for dental caries. Urine samples were tested for cotinine and stool samples were tested for H. pylori. Both cotinine and H. pylori was tested using strips especially prepared based on antigen-antibody reaction (COT, Innovacon Inc., USA, Helicobacter antigen Quick, GA Inc, Germany). Statistical analysis was done using Chi-Square test. The mean age of study participants was 22.37±1.50 years. The mean of teeth with caries was 9.57±4.68. There were 93 (77.5%) students positive for H. pylori, and 100 (83.3%) positive for cotinine. There was a significant relationship between cotinine and caries (P=0.000), and H. pylori and dental caries (P=0.000). The co-existence of H. pylori and cotinine was also significant among cases with caries (P=0.000). The present study showed that cotinine and H. pylori were significantly associated with dental caries. The co-existence of both among cases with dental caries may be a new finding and may work synergistically with each other.

This study estimates and quantifies the prevalence of soft tissue calcifications using CBCT scans of patients. CBCT scans of 624 patients were viewed for evidence of visible soft tissue calcifications of orofacial region. Axial, coronal and sagittal orthogonal CBCT views were analyzed. Data regarding age of the patient, gender, presence or absence of calcification and type of calcification were recorded. The data was analyzed by using unpaired t test and chi-square test. The number of CBCT scans with the evidence of calcification was 159 (25.48%). Most common calcifications were arteriosclerosis (45.91%) and calcified atherosclerotic plaques (31.45%). Females had more percentage of calcifications which was statistically significant. CBCT may prove to be a helpful and early diagnostic tool in detecting soft tissue calcifications.

Mandibular fractures have a high incidence among maxillofacial fractures. Intermaxillary fixation (IMF) is used to treat mandibular fractures and one common procedure involves fixation using steel wire and a splint (wire fixation). This wire fixation offers strong fixing force, but often requires in-hospital management for potential response to the complications such as vomiting. Other difficulties include invasiveness to the patient and the large burden placed on the surgeon during wire fixation. We had been performing IMF using a bilayer thermoforming plate (BTP), and we have good results. This type of IMF employs a bite plate that reproduces the occlusal pattern prior to injury on the basis of models of the maxilla and mandible, and it can be detached on its own. Sufficient fixation was achieved during IMF without bone separation or occlusal deviation. IMF using a removable BTP might be a treatment option that prevents a decrease in quality of life and allows well-maintained oral hygiene without lowering the quality of meals.

Epidermoid cyst often arises in the floor of oral cavity; however, it is relatively rare to arise subcutaneously in the mental region. We reported characteristics of clinical and imaging findings of epidermoid cysts under the skin of the mental region. The patient was a 53-year-old male. He complained of a subcutaneous mass without pain in the left mental region. A palpable soft and movable thumb-sized mass without pain was observed at the first examination. Ultrasound examination revealed a well-demarcated mass with heterogenous hyper-echoic internal echo and posterior echo enhancement. On power Doppler sonography, a small amount of blood supply was found around the periphery of the mass. Plain CT scan revealed a globular soft-tissue mass with peripheral high and central low CT values area. The mass was removed under local anesthesia using intraoral approach. A histopathologic diagnosis was epidermoid cyst. Recurrence is not observed 2 years after surgery. There were only 3 reports of epidermoid cysts in the mental region, including our case in Japan, clinically characteristics of age ranging 20 to 66 years of age and the mean age of 46 years, with 2 males and 1 female. The size was from 20 mm to 12 mm in diameter and from the tip of a thumb up to the tip of a small finger. Ultrasound images of the inside of epidermoid cysts that we experienced this time showed enhancement of relatively uniform hyperechoic image and posterior echo, which was characteristically slightly different from findings of epidermoid cysts generally reported.