[Computer aided design and three-dimensional printing for apicoectomy guide template].

OBJECTIVE: To establish an apicoectomy guide template design and manufacturing method, based on multi-source data fusion, computer aided design (CAD) and fused deposition modeling (FDM). The feasibility of the guide template was preliminary evaluated by the in vitro model experiment. METHODS: An extracted upper anterior tooth, after root canal treatment, was optical scanned, after which the extracted upper anterior tooth was poured in an apicoectomy plaster model. Cone-beam computed tomography (CBCT) scanning of the apicoectomy plaster model was performed, after which optical scanning of the plaster model for apical resection surgery was carried out. All of the relevant CBCT and optical scanning data of the extracted upper anterior tooth and the apicoectomy plaster model were introduced into the Geomagic Studio 2012 software. The multi-source data fusion technology was used to virtually simulate the three-dimensional positional relationship of the extracted tooth, the dentition, the alveolar bone and the gingival, based on which, the three-dimensional design of the apicoectomy guide template was completed in the Geomagic Studio 2012 software. With the technology of fused deposition modeling, the apical resection surgical guide template was three-dimensionally printed with the material of polylactic acid (PLA). Under the guidance of the surgical guide template, the root apical resection was performed on the plaster model. After the apicoectomy, the extracted upper anterior tooth was taken off from the apicoectomy plaster model and then was given the optical scanning. The apical resection length and angle were calculated by the function of distance measurement and angle measurement, and the results were compared with the preset values. RESULTS: The length of the apical resection was 2.88 mm along the direction of the long axis of the tooth, which was 0.12 mm lower than the preset 3 mm. The included angle between the apical resection plane and the long axis of the tooth was 77.9°, 12.1° lower than the preset 90°. CONCLUSION: This study successfully established a digital design and production method of apicoectomy guide template by combing the multi-source data fusion, CAD and FDM technology. The design route and the production method are feasible. The study will provide a technology and methodology reference for the development of domestic special software for the digital design of apicoectomy guide template.

Effect of dietary roughage level on chewing activity, ruminal pH, and saliva secretion in lactating Holstein cows.

Increasing dietary roughage level is a commonly used strategy to prevent subacute ruminal acidosis. We hypothesized that high-roughage diets could promote chewing activity, saliva secretion, and hence more alkaline to buffer rumen pH. To verify the hypothesis, 12 multiparous Holstein cows in mid lactation were randomly allocated to 4 treatments in a triplicated 4 × 4 Latin square experiment with one cow in each treatment surgically fitted with a ruminal cannula. Treatments were diets containing 40, 50, 60, or 70% of roughage on a DM basis. Increasing dietary roughage level decreased DM, CP, OM, starch, and NEL intake, increased ADF intake, and decreased milk yield linearly. Intake of NDF was quite stable across treatments and ranged from 7.8 to 8.1 kg/d per cow. Daily eating time increased linearly with increased roughage level. The increase in eating time was due to increased eating time per meal but not number of meals per day, which was stable and ranged from 8.3 to 8.5 meals per day across treatments. Increasing dietary roughage level had no effect on ruminating time (min/d), the number of ruminating periods (rumination periods per d), and chewing time per ruminating period (min/ruminating period). Ruminating time per kilogram of NDF intake and total chewing time per kilogram of ADF intake were similar across treatments (57.4 and 183.8 min/kg, respectively). Increasing dietary roughage level linearly increased daily total chewing time; linearly elevated the mean, maximum, and minimum ruminal pH; and linearly decreased total VFA concentration and molar proportion of propionate in ruminal fluid. Saliva secretion during eating was increased, the secretion during rumination was unaffected, but the secretion during resting tended to decrease with increased dietary roughage level. As a result, total saliva secretion was not affected by treatments. In conclusion, the results of the present study did not support the concept that high-roughage diets elevated ruminal pH through increased salivary recycling of buffering substrates.

CpG ODN-induced matrix metalloproteinase-13 expression is mediated via activation of the ERK and NF-κB signalling pathways in odontoblast cells.

AIM: To investigate the effects of CpG ODN (CpG oligodeoxynucleotides) to model the action of bacterial challenge on pulpal matrix metalloproteinase-13 (MMP-13) expression and elucidate the associated intracellular signalling pathways. METHODOLOGY: Real-time PCR was used to detect the effects of CpG ODN on MMP-13 mRNA expression levels in a murine odontoblast-lineage cell line (OLCs). The possible involvement of TLR9/MyD88, NF-κB or MAPK pathways involved in the CpG ODN-induced MMP-13 expression was examined by real-time PCR, transient transfection, luciferase activity assay and ELISA. Western blotting was performed to assay the phosphorylation of ERK at a range of time points. RESULTS: MMP-13 was constitutively expressed in OLCs, and their exposure to CpG ODN significantly increased MMP-13 expression. Pre-treatment of OLCs with the inhibitory peptide MyD88, or chloroquine, attenuated the CpG ODN-induced expression of MMP-13. Treatment of the OLCs with CpG ODN increased NF-κB-luciferase activity. This activity was decreased by the over-expression of a nondegrading mutant of IκBα (IκBαSR), although enhanced by the over-expression of NF-κB p65. MMP-13 expression induced by CpG ODN was markedly suppressed by NF-κB inhibitors (pyrrolidine dithiocarbamate, PDTC), IκBα phosphorylation inhibitors (Bay 117082) or IκB protease inhibitor (L-1-tosylamido-2-phenylethyl chloromethyl ketone, TPCK). The inhibitor of ERK1/2, U0126, but not inhibitors of p38 MAPK and JNK, SB203580 and SP600125, decreased CpG ODN-mediated MMP-13 expression. CONCLUSION: The CpG ODN-induced MMP-13 expression in OLCs is mediated through TLR9, NF-κB and the ERK pathway indicating that potentially the recognition of CpG ODN by TLR9 on odontoblasts may regulate the remodelling of injured dental pulp and hard tissues by inducing MMP-13 expression.

Efficacy of liposomal bupivacaine vs. traditional anaesthetic infiltration for pain management in total hip arthroplasty: a systematic review and meta-analysis.

In this review, we assess the effectiveness of liposomal bupivacaine against the traditional bupivacaine infiltration in the postoperative management of total hip arthroplasty (THA). Various databases including PubMed Central, Medline, Scopus, Embase, Google Scholar, Cochrane library and ScienceDirect (inception date till August 2020) were searched. The quality of published trials was assessed using Cochrane risk of bias tool, and a random-effects model was used for meta-analysis. We report pooled Risk ratios (RR) or pooled Standardized Mean difference (SMD) with 95% confidence intervals (CIs). We analyzed a total of 13 studies with 62,582 participants. The majority of the studies were retrospective with lower bias risks. Liposomal bupivacaine was significantly associated with the reduction in opioid requirement at 48 hours (SMD = -0.25; 95% CI: -0.40 to -0.09; p=0.002) and length of hospital stay (SMD = -0.25; 95% CI: -0.43 to -0.07, p=0.006) following THA compared with the control group. However, there was no statistically significant difference between the effect of liposomal bupivacaine and other agents for pain score (24 and 48 hours), opioid requirement at 24 hours and incidence of nausea. Liposomal bupivacaine has selective benefits in terms of opioid consumption and length of hospital stay against the traditional bupivacaine among the patients undergoing THA.

[Three-dimensional finite element analysis of cantilever fixed bridge supported by implants with mandibular central incisor].

Objective: To investigate effect of the contact surface between the bridge and the adjacent teeth on the stress distribution of the implant and bone tissue and the displacement of the prosthesis in the cantilever fixed implant bridge restoring missing mandibular central incisors. Methods: Two-dimensional images of the mandible and dentition in healthy adults were obtained using CT data. A three-dimensional finite element model of cantilever fixed bridge supported by implants with mandibular central incisor was established by computer reconstruction technique.The contact surface between the bridge and the adjacent natural tooth was designed as "oval" and "trapezoid". The "trapezoid" has a slightly smaller median diameter on the labial side and a slightly larger medial diameter on the lingual side. Loading of 120 N was applied on the tangential margin of the middle line of the long axis of the bridge 41. The direction was set at 0°, which was parallel to the long axis of the tooth and downward. The buccal to lingual and downward angles were 30°, 45° and 60°, respectively, perpendicular to the long axis of the tooth and 90° to the lingual side.The stress distribution of the implant and surrounding bone tissue and the displacement of the prosthesis were compared between the two models. Results: Under axial and buccolingual loading, the maximum equivalent stress peak in the implant and surrounding bone tissue in the cantilever with trapezoidal contact surface design and the maximum displacement of the prosthesis were lower. Moreover, the distribution of stress was more balanced and the concentration range of stress was smaller. With the loading angle increasing, this trend was more obvious. When loading angle increased to 90°, the maximum equivalent stress and the maximum displacement of the elliptic contact surface model implant and surrounding bone tissue were 196 and 101 MPa and 0.196 mm, respectively, while the trapezoidal contact surface model were 157 and 72 MPa and 0.164 mm, respectively. Conclusions: The trapezoidal contact surface of the bridge and the adjacent teeth in the cantilever fixed bridge supported by implants with mandibular central incisor is beneficial to reduce the impact of the leverage on the implant and surrounding bone tissue.

The Co-film-thickness dependent lateral photoeffect in Co-SiO2-Si metal-oxide-semiconductor structures.

We report a transient lateral photoeffect (LPE) in thin metallic Co films deposited on n-type Si substrates with native SiO(2) surfaces. Under the nonuniform irradiation of a laser beam, the lateral phtovoltage (LPV) shows high sensitivity to the laser position in the metal film plane. This effect can be interpreted by the metal-semiconductor (MS) junction formed between metal and semiconductor. The LPV depends significantly on the thickness of Co film. The position sensitivity shows a peak value of 42.6 mV/mm for Co(2.8mn)-SiO(2)-Si and decreases greatly with the increase of the Co film thickness. We explain that by the shorting effect of the metallic film.

[Surface roughness and gloss of novel flowable composites after polishing and simulated brushing wear].

Objective: To investigate surface properties of novel flowable composites after polishing and simulated brushing wear, compared to their pasty counterpart. Methods: Composites employed in this study were: three flowable composites (A1: Clearfil Majesty ES Flow; B1: Beautifil Flow Plus F00; C1: Filtek Bulk Fill) and three paste composites (A2: Clearfil Majesty; B2: Beautifil; C2: Filtek Z350. Eleven disk-shaped specimens were made for each material. The specimens were cured, then subjected to sandpaper finishing for 20 s, one-step polishing for 30 s, finally subjected to simulated brushing for 10 000 cycles. Surface roughness and glossiness were measured before finishing, after finishing, after polishing, after 5 000 brushing cycles and after 10 000 brushing cycles, respectively. Data obtained were analyzed using two-way ANOVA method. Scanning electron microscope was employed to examine the microscopic appearance of each material. Results: Surface roughness (0.11~0.22 µm) and glossiness (74.25~86.48 GU) of each material were similar after one-step polishing. After brushing simulation, roughness increased significantly and glossiness decreased significantly for each material (P<0.05). Group A1 presented the best gloss ([50.68±1.58] GU) after final wear (P<0.05). Flowable composites of group A1 and B1 tested in the present setup showed better surface properties compared to their pasty counterpart (group A2 and B2). Conclusions: Within the limit of this study, flowable composites tested in the present research can obtain similar surface polish or even better than the paste composite counterpart.

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-based scaffolds for tissue engineering.

Development and selection of an ideal scaffold is of importance for tissue engineering. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a biocompatible bioresorbable copolymer that belongs to the polyhydroxyalkanoate family. Because of its good biocompatibility, PHBHHx has been widely used as a cell scaffold for tissue engineering. This review focuses on the utilization of PHBHHx-based scaffolds in tissue engineering. Advances in the preparation, modification, and application of PHBHHx scaffolds are discussed.

Surface functionalization of polycaprolactone films via surface-initiated atom transfer radical polymerization for covalently coupling cell-adhesive biomolecules.

The ability to manipulate and control the surface properties, without altering the substrate properties, is of crucial importance in the designing of biomedical materials. In this work, surface-initiated atom transfer radical polymerization (ATRP) is employed to tailor the functionality of polycaprolactone (PCL) film surfaces in a well-controlled manner. Functional polymer brushes of glycidyl methacrylate (GMA) were prepared via surface-initiated ATRPs from the PCL film surfaces. Kinetics study revealed that the chain growth from the PCL films was consistent with a controlled process. The dense and reactive epoxide groups of the grafted P(GMA) brushes were used for the direct coupling of cell-adhesive collagen and Arg-Gly-Asp-Ser (RGDS) peptides to improve the cell-adhesion properties of the PCL film surface. These modified surfaces were evaluated by culturing of a cell line, 3T3 fibroblasts. The cell attachment and proliferation were improved remarkably on the collagen (or RGDS) functionalized PCL film surfaces. The adhesion results also indicated that the collagen-coupled PCL film surface is better for the cell-adhesion process. With the versatility of surface-initiated ATRP and the good biocompatibility nature of biomolecules, the PCL films with desirable surface functionalities can be precisely tailored to cater to various biomedical applications.

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-based scaffolds for tissue engineering

Development and selection of an ideal scaffold is of importance for tissue engineering. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a biocompatible bioresorbable copolymer that belongs to the polyhydroxyalkanoate family. Because of its good biocompatibility, PHBHHx has been widely used as a cell scaffold for tissue engineering. This review focuses on the utilization of PHBHHx-based scaffolds in tissue engineering. Advances in the preparation, modification, and application of PHBHHx scaffolds are discussed.

[Clinical analysis of 40 cases of malignant tumor of the floor of the mouth]

This is a retrospective review for 40 patients with malignant tumour of the floor of mouth.In the group,squamous carinoma is 62.5%.adenoid cystic carcinoma is 22.5%.Both of them are the major type,stage III.IV were 72.5%,Generally ipsilateral;radical mandibular and neck dissection was performed sellectively.65% of patient were given preoprative chemotherapy.Total 5 years survival rate was 50%,for stage I-III were 78.6%.Although preoperative chemotherapy was given that the group of lower pathological differetiation was still in lower survival rate,higher recurrence and mortality than those given surgery alone. Survival rate for squamous carcinoma was higher than that for adenoid cystic carcinoma.

[A comparison of the effects of 180kv X-ray radiation and cobalt-60 radiation on the jaws of the guinea pigs]

OBJECTIVE: Study of the effects of 180kv x-ray and cobalt-60 radiation on jaws and enhance the understanding of pathology of osteroradionecrosis of jaws(ORNJ).METHODS: 128 guinea pigs were grouped according to different irradiation sources and doses.Fractioned radiation from both sources was delivered in right mandible.The teeth extractions were conducted one week prior to radiation and 1,3,5 months after radiation respectively.Following radiation,the guinea pigs were examined by gross observation, x-ray film and histopathological examination at regular interval. RESULTS: Bone resorption occured within 1 month after irradiation as result of osteoblast inhibition and osteoclast activation.From 2 to 4 month afterwards,the number of osteocytes reduced and pyknosis, empty lacunae as well as obliteration of small vessels in periodontal membrane were commonly seen.The teeth extractions conducted at 3 months,5 months after radiation lead to ORNJ in 7 amimals (14.6%).CONCLUSION: 180kv x-ray radiation was far more damaging to jaws than cobalt-60 radiation.The dental extraction is an important factor inducint the development of ORNJ.

Experimental study of radiation effect on the mandibular microvasculature of the guinea pig.

OBJECTIVE: This experimental study was performed to explore the intraosseous microvascular alterations in the irradiated mandible and to increase understanding of the pathogenesis of osteoradionecrosis. METHODS: One hundred twenty-eight guinea pigs were grouped according to different radiation sources and dosages. Fractioned radiation was delivered to the right mandibles. Dental extractions were conducted at 1, 3, and 5 months respectively, after radiation. One month later, the animals were examined by means of gross observation, histopathology, and microvascular corrosion castings. RESULTS: Histologic evaluation showed bone absorption within 2 months following radiation. Four months later, the number of osteocytes decreased and pyknosis and empty lacunae were commonly seen. The casting specimens revealed under scanning electron microscopy that capillary disconnection and obliteration with subsequent vein shrinkage aggravated over time. In the nonhealing dental extraction site, a large-scale vascular network defect presented with focal capillary proliferation around. CONCLUSIONS: The capillary is the part most vulnerable to the damage caused by radiation in the vascular system of the mandible. On the basis of "hypovascular, hypoxic, hypocellular" structure, local microcirculation failure induced by the trauma-repairing process leads to occurrence of osteoradionecrosis of jaws.