组织工程用于修复慢性牙周组织缺损的动物实验研究

目的:应用细胞型和/或非细胞型组织工程化牙周组织移植修复慢性牙周缺损的动物实验,探讨其用于牙周再生治疗的可行性。方法:人工构建5只成年杂种狗慢性牙周缺损病变模型,分别随机采用:引导组织再生治疗术+富血小板血浆+B ioOss(GTR+PRP+B ioOss)、引导组织再生治疗术+富血小板血浆+B ioOss+自体牙周膜细胞(GTR+PRP+B ioOss+PDLCs)、引导组织再生治疗术+自体牙周膜细胞(GTR+PDLCs)和GTR治疗,其中GTR组6颗牙,其余3组各为8颗牙。12周后作病理切片,HE染色观察牙周组织再生情况。结果:动物实验发现GTR组的新生牙槽骨、牙骨质和牙周组织高度分别为(0.52±0.21)mm、(0.8±0.13)mm、(1.9±0.10)mm。而另外3组的新生牙槽骨、牙骨质和牙周组织高度分别为GTR+PRP+B ioOss组:(1.36±0.17)mm、(1.92±0.18)mm、(2.62±0.16)mm;GTR+PRP+B ioOss+PDLCs组:(1.42±0.22)mm、(2.07±0.19)mm、(2.68±0.20)mm;GTR+PDLCs组:(1.39±0.19)mm、(1.82±0.16)mm、(2.55±0.12)mm,这3组牙槽骨、牙骨质和牙周组织的修复再生效果均明显优于GTR组(P<0.05),而它们之间的差别无显著性。结论:应用GTR技术结合组织工程可显著促进狗牙周组织缺损的再生。     

羟基磷灰石涂层热处理晶化工艺研究

目的：通过热处理方法提高羟基磷灰石（HA）涂层的结晶度、使脱落的羟基得到恢复。方法：通过等离子喷涂和热处理试验，利用X射线衍射（XRD）和红外吸收光普分析等手段研究了热处理对羟基磷石涂层相组成的影响。结果：热处理可使涂层中的非晶相发生晶化，并使羟基得到恢复；随着热处理温度的提高，涂层的结晶度提高，α－TCP等热分解相逐步转变为羟基磷灰石。保温时间达到2小时后，延长保温时间并不能提高涂层的结晶工。结论：在大气环境下，涂层的最佳热处理工艺是在700℃下保温2小时。     

血小板血浆对人牙髓细胞增殖的影响

目的：观察血小板血浆及其细化成分对人牙髓细胞增殖的影响。方法：使用因正畸而拔除的人牙的牙髓细胞，用细胞定量测定试剂盒测定细胞增殖情况。结果：5％的多血小板血浆（platelet-rich plasma，PRP）、5％和10％的洗净血小板（washed platelet，WPLT）均明显地促进了人牙髓细胞的增殖，而且WPLT的作用较PRP更显著。乏血小板血浆（platelet-poor plasma，PPP）呈浓度依赖性地抑制了人牙髓细胞增殖，5％WPLT促进人牙髓细胞增殖的作用。结论：去除血浆成分的WPLT对培养的人牙髓细胞增殖有明显的促进作用；血浆中可能存在对抗血小板生长因子作用的因子。     

Professional oral hygiene as a therapeutic option for pediatric patients with plasma cell gingivitis: preliminary results of a prospective case series

Background: Plasma cell gingivitis (PCG) is a rare, benign inflammatory condition of unclear etiology with no definitive standard of care ever reported to our knowledge. The aim of this case series is to ascertain the clinical efficacy of professional oral hygiene and periodontal therapy in younger individuals with a histologically confirmed diagnosis of PCG. Methods: All patients received non‐surgical periodontal therapy, including oral hygiene instructions, and thorough supragingival scaling and polishing with the removal of all deposits and staining combined with the use of antimicrobials in a 9‐week cohort study. Clinical outcome variables were recorded at baseline and 4 weeks after the intervention and included, as periodontal parameters, full‐mouth plaque scores (FMPS), full‐mouth bleeding scores (FMBS), the clinical extension of gingival involvement, and patient‐related outcomes (visual analog score of pain). Results: A total of 11 patients (six males and five females; mean age: 11 ± 0.86 years) were recruited. Four weeks after finishing the oral hygiene and periodontal therapy protocol, a statistically significant reduction was observed for FMPS (P = 0.000), FMBS (P = 0.000), reported pain (P = 0.003) and clinical gingival involvement (P = 0.003). Conclusion: Standard, professional oral hygiene procedures and non‐surgical periodontal therapy including antimicrobials were associated with a marked improvement of clinical and patient‐related outcomes in pediatric cases of PCG.     

Treatment of intrabony periodontal defects with platelet-rich plasma versus platelet-poor plasma combined with a bovine-derived xenograft: a controlled clinical trial

Background: The purpose of this study is to assess the healing outcomes of intrabony defects after treatment with platelet‐rich plasma (PRP) versus platelet‐poor plasma (PPP) combined with bovine‐derived xenograft (BDX). Methods: Using a split‐mouth design, a total of 79 intrabony defects with an intrabony component of ≥3 mm in 20 patients were treated either with PRP/BDX (group 1) or PPP/BDX (group 2). At baseline and 12 months after surgery, plaque and sulcus bleeding indices, probing depth (PD), relative attachment level, recession, and probing and radiographic bone levels were recorded. Results: After 12 months, groups 1 and 2 presented a mean PD reduction of 3.87 ± 0.86 and 3.76 ± 0.80 mm, recession of 1.35 ± 0.68 and 1.58 ± 0.54 mm, attachment gain of 2.51 ± 0.97 and 2.18 ± 0.87 mm, clinical bone gain of 2.18 ± 0.86 and 2.09 ± 0.89 mm, and radiographic bone gain of 2.11 ± 0.87 and 2.19 ± 0.96 mm, respectively. Intergroup differences were found to be insignificant. Conclusions: Within its limits, these results suggest that the outcomes of the treatment after PRP/BDX and PPP/BDX applications in intrabony defects are similar. When the platelet counts are taken into consideration, PPP seems to demonstrate similar clinical efficacy as the PRP.     

Plasma catecholamine and haemodynamic responses to surgical endodontic anaesthetic protocols

The effects of varying clinically relevant patterns of anaesthetic-vasoconstrictor combinations used for peri-radicular surgery on plasma concentrations of catecholamines and haemodynamic responses was studied in the canine model. Five mongrel dogs were anaesthetized with sodium pentobarbital. A femoral canula was inserted to measure central blood pressure and an ECG was used to monitor heart rate and any associated arrhythmias. Femoral venous blood samples were drawn before initial injection and at 3 and 10 min after injections. Plasma catecholamine concentrations were determined using high pressure liquid chromatography (HPLC). Injection protocols used three time periods, 30, 60 and 90s, with solutions containing 1:100000 and 1:50000 adrenaline. No significant changes in heart rates or presence of arrythymias were noted over the experimental protocol. Catecholamine levels in pico moles mL^-1 were within the normal range at the 3-min sample level. At the 10-min sample time there was a more erratic range of concentrations, with most samples within the normal range. This may have been due to endogenous release of catecholamines in specific animals. The data identified trends in both the haemodynamic parameters and plasma catecholamine levels that can legitimately support the careful use of higher levels of a vasoconstrictor when patient profiles and surgical needs dictate.     

Sinus floor elevation applied tissue-engineered bone. Comparative study between mesenchymal stem cells/platelet-rich plasma (PRP) and autogenous bone with PRP complexes in rabbits

In the present study, we compared bone regeneration ability in sinus floor elevation between a tissue engineering method using mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP), and a promising new method using particulate cancellous bone and marrow (PCBM) and PRP. Bilateral sinus floor elevation procedures were performed in 18 adult Japanese white rabbits. MSCs/PRP or PCBM/PRP complexes were grafted to each maxillary sinus in the same rabbits. The MSCs were isolated from rabbit iliac crest marrow, and PRP was obtained from peripheral blood. PCBM were collected from the rabbit iliac crest and mixed with PRP. The animals were sacrificed at 2, 4, and 8 weeks after transplantation, and the bone formation ability of each implant was evaluated histologically and histometrically. According to the histological observations, both sites (MSCs/PRP and PCBM/PRP) showed well newly formed bone and neovascularization at 2 and 4 weeks. However, at 8 weeks, the lamellar bone was observed to be occupied by fatty marrow in large areas in both sites. There was no significant difference in bone volume or augmented height between MSCs/PRP and PCBM/PRP groups each week, but there were significant differences in bone volume and augmented height between 2 and 8 weeks in PCBM/PRP or MSCs/PRP groups and in bone volume between 4 and 8 weeks in the PCBM/PRP group (P<0.05). These results suggest that the MSCs/PRP complex may well be used for bone regeneration in sinus floor elevation, compared with the PCBM/PRP complex.     

Platelets stimulate proliferation of bone cells: involvement of platelet-derived growth factor,microparticles and membranes

Platelets have been implicated in accelerated bone regeneration in grafting applications. The beneficial effects of platelets may involve their ability to stimulate the proliferation of osteoblasts. We therefore determined the mitogenic response of human trabecular bone-derived cells to human platelets and supernatants of thrombin-activated platelets. We can show a approximately 50-fold increase in DNA-synthesis of bone cells (BC) cultured in the presence of platelets as determined by [3H]-thymidine incorporation. Preventing cell-to-cell contact by a membrane filter did not abrogate the stimulatory effect, indicating the release of soluble factor(s) that are mitogenic for BC. The lipid fraction of the platelets had no effect on [3H]-thymidine uptake into the DNA of BC. Platelet-released supernatant (PRS) increased the rate of [3H]-thymidine incorporation to approximately 20-fold and retained 56% of their activity after incubation at 56 degrees C, and 27% at 100 degrees C, respectively. Neutralizing antibodies raised against platelet-derived growth factor (PDGF) partially suppressed the mitogenic potential of PRS. Gel exclusion chromatography analysis showed that molecules ranging from 25 kDa to more than 70 kDa within the PRS can stimulate BC proliferation. The highest amount of PDGF was detected in fractions corresponding to a molecular weight of 28-37 kDa as determined by immunoassay. The mitogenic activity was not restricted to soluble growth factors because microparticles in the PRS and platelet membranes also increased BC proliferation. Our data indicate that native platelets, the respective PRS, microparticles, and platelet membranes can stimulate the mitogenic activity of BC, thereby contributing to the regeneration of mineralized tissue.     

Effect of platelet-rich plasma on the healing of intrabony defects treated with an enamel matrix protein derivative and a natural bone mineral

Background: Regenerative periodontal surgery utilizing a combination of an enamel matrix protein derivative (EMD) and a natural bone mineral (NBM) and platelet‐rich plasma (PRP) has been shown to enhance the outcomes of regenerative surgery significantly. At present, it is unknown whether root conditioning with EMD, followed by defect fill with a combination of NBM+PRP may additionally enhance the clinical results obtained with EMD+NBM. Aim: To compare clinically the treatment of deep intrabony defects with either EMD+NBM+PRP or EMD+NBM. Material and Methods: Twenty‐six patients suffering from advanced chronic periodontitis, and each of whom displayed one advanced intrabony defect were randomly treated with either EMD+NBM+PRP (test) or EMD+NBM (control). The following clinical parameters were evaluated at baseline and at 1 year after treatment: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR) and clinical attachment level (CAL). The primary outcome variable was CAL. Results: Healing was uneventful in all patients. At 1 year after therapy, the test sites showed a reduction in mean PD from 8.8±1.9 mm to 3.1±0.9 mm ( p<0.001) and a change in mean CAL from 10.8±2.0 mm to 6.0±1.5 mm ( p<0.001). In the control group the mean PD was reduced from 8.8±2.0 mm to 2.8±1.6 mm ( p<0.001) and the mean CAL changed from 10.5±1.6 mm to 5.5±1.4 mm ( p<0.001). CAL gains of 4 mm were measured in 77% (i.e. in 10 out of 13 defects) of the cases treated with EMD+NBM+PRP and in 100% (i.e. in all 13 defects) treated with EMD+NBM. No statistically significant differences in any of the investigated parameters were observed between the two groups. Conclusions: Within its limits, the present study has shown that (i) 1 year after regenerative surgery, both treatments resulted in statistically significant PD reductions and CAL gains and (ii) the use of PRP failed to enhance the results obtained with EMD+NBM.     

Evaluation of sinus floor elevation using a composite bone graft mixture

BACKGROUND: The performance of implant surgery in the posterior maxilla often poses a challenge due to insufficient available bone. Sinus floor elevation was developed to increase needed vertical height to overcome this problem. The present study described and reported a simple, safe and predictable bone graft mixture for the sinus lifting procedure. MATERIAL AND METHODS: Seventy patients were recruited for this study and underwent a sinus lift procedure. All sites were treated with a composite graft of cortical autogenous bone, bovine bone and platelet-rich plasma (PRP). A total of 263 implants (171 Astra Tech and 92 Microdent) were placed either simultaneously or delayed. All sites were clinically and radiographically evaluated 24 months after their prosthetic loading. Biopsy samples were taken from 16 delayed implant placement sites at the time of their implant placement. RESULTS: A 100% implant success rate was found after 24 months of functioning. Only two Microdent implants failed before loading, which translates to a 99% overall implant success rate. No statistically significant differences were found between simultaneous and delayed implant placement. Image processing revealed 34+/-6.34% vital bone, 49.6+/-6.04% connective tissue and 16.4+/-3.23% remaining Bio-Oss particles. However, the histomorphometric analysis showed that the bovine bone was incorporated into new bone formation. CONCLUSION: The results showed that a composite graft comprised of cortical autogenous bone, bovine bone and PRP mixture can be successfully used for sinus augmentation.