Effects of Er:YAG laser and ultrasonic treatment on fibroblast attachment to root surfaces: an in vitro study

BACKGROUND: The aim of this study was to analyze the effects of erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser and ultrasonic treatment on fibroblast attachment to periodontally diseased root surfaces. METHODS: Thirty single-rooted human periodontally involved teeth were included in this study. A total of 60 specimens were obtained from all selected teeth and were randomly assigned to the following three groups: group A, untreated control group; group B, ultrasonic group; and group C, Er:YAG laser at 160 mJ/pulse at 10 Hz group. All of the specimens were incubated in petri dishes with fibroblast suspension and observed by scanning electron microscopy. RESULTS: Laser-treated specimens showed a significantly higher cell density number, with a mean+/-SD of 3,720+/-316 cells/mm2. The ultrasonically treated group showed a lower cell density number, with a mean+/-SD of 658+/-140 cells/mm2. The untreated control group showed the lowest cell density number, with a mean+/-SD of 130+/-80 cells/mm2. Differences between all groups were significant (P<0.0001). CONCLUSION: The results of the study indicate that untreated control surfaces and ultrasonically treated surfaces exhibited a significantly lower number of attached cells compared to laser-treated specimens, which showed a significantly higher cell density number.     

Ultrastructural study of initial attachment by human fibroblast-like cells on tooth roots in vitro

The purpose of this study was to determine the longitudinal effect of demineralized treatment of root surfaces on initial attachment, growth and differentiation of human periodontal ligament fibroblast-like cells in vitro. Cementum and dentin fragments were prepared from intact extracted human teeth for orthodontic reason. The root fragments of one group were not demineralized. Those of the other groups were demineralized by either citric acid (pH = 1.0, 3 min) or EDTA (pH = 7.4, 30 min). Plastic sheets served as controls. Human periodontal ligament fibroblast-like cells were incubated on root fragments and plastic sheets. After incubation, the root fragments and plastic sheets were examined by electron microscopy. The collagen fibers were exposed to the root surface by demineralized root surface. The exposed collagen fibers showed an effect on the cell attachment and growth, and the cells produced collagen fibers in the extra-cellular space of the root surface. Demineralization of dentin fragments were more strongly affected in cell attachment, growth and differentiation than demineralization of cementum fragments. Citric acid demineralization of dentin fragments had a greater effect on cell attachment, growth and differentiation than EDTA demineralization of dentin fragments. The results suggest that citric acid demineralization of dentin fragments may provide the most effective dental surface for the establishment of connective tissue attachment after periodontal treatment.     

釉基质蛋白对人牙周膜细胞粘附、伸展的影响

目的：了解釉基质蛋白对人牙周膜细胞黏附，伸展的影响。方法：改良组织块法培养人牙周膜细胞，固相结合分析方法观察釉基质蛋白对人牙周膜细胞黏附，伸展的影响。结果：实验组PDLC黏附率与对照组无差别，实验组PDLC伸展率高于对照组。结论：EMPs对PDLC黏附无影响，但可促进其伸展。     

An in vitro study of non-axial forces upon the retention of an O-ring attachment

Objective: The purpose of this study was to evaluate the retention force of an O-ring attachment system in different inclinations to the ideal path of insertion, using devices to compensate angulations.
Material and methods: Two implants were inserted into an aluminum base, and ball attachments were screwed to implants. Cylinders with O-rings were placed on ball attachments and connected to the test device using positioners to compensate implant angulations (0°, 7°, and 14°). Plexiglass bases were used to simulate implant angulations. The base and the test device were positioned in a testing apparatus, which simulated insertion/removal of an overdenture. A total of 2900 cycles, simulating 2 years of overdenture use, were performed and 36 O-rings were tested. The force required for each cycle was recorded with computer software. Longitudinal sections of ball attachment–positioner–cylinder with O-rings of each angulation were obtained to analyze the relationship among them, and O-ring sections tested in each angulation were compared with an unused counterpart. A mixed linear model was used to analyze the data, and the comparison was performed by orthogonal contrasts (α=0.05).
Results: At 0°, the retention force decreased significantly over time, and the retention force was significantly different in all comparisons, except from 12 to 18 months. When the implants were positioned at 7°, the retention force was statistically different at 0 and 24 months. At 14°, significant differences were found from 6 and 12 to 24 months.
Conclusions: Within the limitations of this study, it was concluded that O-rings for implant/attachments perpendicular to the occlusal plane were adequately retentive over the first year and that the retentive capacity of O-ring was affected by implant inclinations despite the proposed positioners.     

Influence of titanium surface roughness on attachment of Streptococcus sanguis: an in vitro study

The purpose of the present study was to investigate the efficacy of the decontamination protocol for bacterial removal in titanium surfaces with three different levels of roughness using a high-pressure sodium bicarbonate device for 1 minute under aseptic conditions. Group 1 was composed of 10 as-machined titanium sheets and Groups 2 and 3 of titanium sheets blasted with aluminum oxide (Al2O3, alumina) particles with different diameters: Group 2 was blasted with 65-microm particles and Group 3 with 250-microm particles. The titanium specimens were sterilized and incubated in tubes containing a suspension of Streptococcus sanguis. The colony-forming units were counted before and after the application of the decontamination protocol. The arithmetic mean roughness (R(a)) per group was: Group 1, 0.17 microm +/- 0.01; Group 2, 1.14 microm +/- 0.15; and Group 3, 3.17 microm +/- 0.23. After the contamination period, Group 1 remained with 49 x 10(3) bacterial cells, and the bacterial concentrations of Groups 2 and 3 were 11 x 10(4) and 35 x 10(5), respectively. After the application of the decontamination protocol, no viable bacteria were detected. With the increase of the surface roughness, an exponential increase in bacterial cells was observed. The results showed that the decontamination protocol treatment with a high-pressure sodium bicarbonate device efficiently removed all bacterial cells in all surfaces tested. This indicates that high-pressure sodium bicarbonate spray should be used in the maintenance phase of implant treatment.     

牙骨质附着蛋白对猴骨髓基质细胞增殖和矿化能力的影响

目的观察牙骨质附着蛋白（CAP）对体外培养的猴骨髓基质细胞增殖及矿化能力的影响。方法抽取猴髂骨骨髓，全血培养法获得骨髓基质细胞。培养液中CAP的浓度分别为0．125、0．25、0．5、1、2μg／ml，以不加CAP为空白对照。MTF法测定各组细胞的增殖活性，同时检测细胞内碱性磷酸酶活性。采用SAS6．12软件对实验数据行单因素方差分析。结果从第3天开始，0．5、1、2μg／ml CAP组与对照组相比能显著促进细胞增殖。对照组与不同浓度CAP实验组对细胞内碱性磷酸酶合成差异无统计学意义。结论0．5～2μg／ml的CAP都能显著促进体外培养的猴BMSCs增殖，但各浓度组CAP对细胞内碱性磷酸酶合成无影响。     

Influence of attachment and bone loss on the mobility of incisors and canine teeth

Abstract

Objective. The purpose of this clinical study was to evaluate the correlation between tooth mobility (TM), crown-to-root ratio (CRR) and clinical attachment loss (CAL) in periodontally-compromised participants. Materials and methods. While slowly biting on a load cell, the mobility of the upper incisors and canine teeth of 20 volunteers was measured using a photogrammetric measurement technique. An automated software program recorded the force-related three-dimensional TM at 3-N intervals. CAL was assessed clinically and CRR values were assessed radiographically. For each contralateral pair of teeth (central, lateral incisor, canine) and for each main level of force, the Pearson product-moment correlation coefficient between TM and CRR and between TM and CAL was computed. Correlations were considered statistically significant at p < 0.05. Results. Statistically significant positive correlations were found between TM and CRR for incisors and canines for each main level of force, whereas canines had the lowest correlation. Statistically significant positive correlations were also found between TM and CAL for the central and lateral incisors at each main level of force. Canines showed no significant correlation between CAL and TM, regardless of force level. Conclusion. The loss of attachment and bone seem to have more influence on the mobility of incisors than canines.     

Effects of the Nd:YAG laser and combined treatments on in vitro fibroblast attachment to root surfaces

Abstract The purpose of this in vitro study was to evaluate the effects of the Nd:YAG laser either alone or in combination with root planning or air-powder abrasive treatment on fibroblast attachment to non-diseased root surfaces. 28. 4x4 mm root specimens and four disc-shaped root specimens 6 mm in diameter were obtained from unreputed 3rd molars. The root segments were randomly assigned to 4 treatment groups: (1) control: (2) laser-only treated: (3) laser treated followed by root planning; (4) laser treated followed by air-powder abrasive treatment. Laser-treated root specimens were exposed for 1 min with the Nd:YAG laser calibrated at an energy setting of 75 mJ at 20 pulses/s using a 320 μm contact fiber. The contact fiber was held parallel to the root segments and the root segments were kept moist with distilled water. Following the prescribed treatments, the root specimens were incubated with fibroblast cultures and then prepared for SEM examination. Results of cell counts of fibroblasts attached to specimens within each treatment group yielded the following means and standard deviations: control groups. 181.64 ± 44.74; lased only, 78.57 ± 21.35; lased and root planed 125.35 ± 26.13: and lased followed by an air-powder abrasive, 177.28 ± 55.71. Application of ANOVA followed by the Dunn Multiple Comparison test revealed significant differences (p<0.01) in the number of attached cells between the control and laser-only treated groups: and between the laser-only and laser/air-powder abrasive treated groups. The decreased fibroblast attachment observed in the laser-only treated group suggests a laser-induced bio in compatibility of the root surface. Several surface alterations including ablation of cementum with exposure of dentinal tubules and crater formation were observed. Increased numbers of fibroblasts were seen attached to the lased root segments after root planning or after exposure to an air-powder abrasive, indicating that the laser-induced bioincompatibility is reversible and most likely a surface phenomena. A pilot study using pholoacoustic Fourier transform infrared spectroscopy revealed reductions in the intensity of the Amide II band between 1500–1550 cm-1, suggesting the laser exposure denatures surface protein which, in turn, may contribute to inhibition of fibroblast attachment.     

Effect of diode laser irradiation on the attachment rate of periodontal ligament cells: an in vitro study.

BACKGROUND: The present study is part of a basic research program investigating the cellular effects of an 810 nm GaAlAs-diode laser on human periodontal tissues. The aim of the investigation was to evaluate the effects of laser treatment of root surface specimens on the attachment of periodontal ligament (PDL) cells in vitro. METHODS: Root specimens were prepared from periodontally diseased teeth. PDL cells were obtained from human third molar ligaments. Cells were cultured under simple, standardized, and reproducible experimental conditions. One hundred fifty root specimens were scaled and root planed with curets followed by air-powder abrasive treatment; 75 were then lased and 75 served as controls. The irradiation time was 20 seconds at a power output of 1 W. The root segments were placed into culture dishes, covered with a solution of PDL cells, and incubated for 72 hours. The specimens were then washed with phosphate buffer to remove cells not attached to the surface, and the adherent cells were stained with methylene blue. Cells were counted using a reflected light microscope and the cell density per mm2 was calculated. RESULTS: The analysis of 150 specimens revealed no significant differences between the groups (P = 0.347, Wilcoxon test). The cell numbers, however, were slightly higher on laser specimens. The mean was 66 cells/mm2 in the laser group and 63.7 cells/mm2 in the control group. CONCLUSIONS: The application of the diode laser at the parameters used did not have a substantially positive effect on the new attachment of PDL cells on the tooth specimens. It remains to be investigated whether the difference detected is really clinically relevant.     

釉基质蛋白对猪骨髓基质细胞黏附、伸展及增殖的影响

目的：研究釉基质蛋白（enamel matrix proteins,EMPs）对体外培养的猪骨髓基质细胞（bone marrow stromal cells,BMSCs）黏附、伸展和增殖活性的影响。方法：抽取猪髂骨骨髓．全血培养法获得骨髓基质细胞。培养液中EMPs的浓度分别为25、50、100、200μg／ml,以不加EMPs为对照。用比色法检测不同浓度EMPs对BMSCs黏附的影响。通过计数预定视野中伸展的细胞数,计算BMSCs在培养1h、3．5h、6、5h后的伸展率。MTT法测定各组细胞的增殖活性。对实验数据行单因素方差分析和SNK法组间比较。结果：猪BMSCs在含有EMPs的培养液中生长良好。对照组以及不同浓度EMPs实验组对细胞黏附的影响无统计学差异。在1h、3．5h、6．5h．各组细胞的伸展率无显著不同。EMPs对BMSCs的促增殖作用呈浓度和时间依赖性．200μg／ml浓度的EMPs从实验的第3天开始．显著促进猪BMSCs的增殖。结论：EMPs对体外培养的猪BMSCs的黏附和伸展无显著影响．200μg／ml浓度的EMPs可显著促进猪BMSCs增殖,为联合应用EMPs和BMSCs修复牙周组织缺损提供了理论依据。     

In vitro study of collagen coating of titanium implants for initial cell attachment

The aim of this study was to examine the influence of collagen coating on titanium on the initial attachment of human gingival fibroblasts for the development of the implant with periimplant soft tissue attachment. The morphological changes of cultured human gingival fibroblasts were investigated by scanning electron microcopy (SEM). Four different surfaces, i.e. non-coated mirror-polished titanium, collagen-coated titanium, non-coated tissue-culture polystyrene, and collagen-coated polystyrene were examined. Collagen coating of titanium was effective for enhancing the initial cell attachment. It is expected that collagen coating of titanium implants will improve the attachment of the peri-implant soft tissue to titanium at early stages after the implantation. SEM observation revealed the morphological effect of collagen coating on both titanium and polystyrene surfaces. Many lamellipodia and filopodia were recognized on collagen-coated titanium or polystyrene. Collagen coating improved the activity of human gingival fibroblasts.     

A study of in vitro attachment of Streptococcus sanguis and Actinomyces viscosus to saliva-treated titanium

This study examined the initial attachment of Streptococcus sanguis G9-B and Actinomyces viscosus T14V to saliva-treated powdered enamel and titanium surfaces. Using an in vitro adherence model, significantly lower numbers of Actinomyces viscosus T14V bound to the saliva-treated titanium surface when compared to that of the similarly treated enamel. The binding of Streptococcus sanguis G9-B to titanium or enamel did not vary significantly. A comparison of the percentage of cells bound to the titanium surface revealed that S sanguis cells attached in significantly higher numbers when compared to the A viscosus cells.     

釉基质蛋白对猪骨髓基质细胞增殖和根面附着生长的影响

目的:研究釉基质蛋白(enamel matrix proteins,EMPs)对体外培养的猪骨髓基质细胞(bone marrowstrom alcells,BMSCs)增殖和在根面附着生长的影响,为EMPs联合应用BMSCs修复牙周组织缺损提供理论依据。方法:抽取猪髂骨骨髓,全血培养法获得骨髓基质细胞。培养液中EMPs的浓度分别为25、50、100、200μg/ml,以不加EMPs为对照。MTT法测定各组细胞的增殖活性。对实验数据行单因素方差分析和SNK法组间比较,检验水准为α=0.05。制备猪自体牙根片,以200μg/mlEMPs处理组为实验组,对照组不用EMPs处理。接种BMSCs后培养7d,HE染色和扫描电镜观察。选取800倍下标准视野,计数每个视野中的细胞数,取4个视野均值。采用配对t检验法作统计学分析,检验水准为α=0.05。结果:猪BMSCs在含有EMPs的培养液中生长良好。EMPs对BMSCs的促增殖作用呈浓度和时间依赖性,200μg/ml浓度的EMPs从实验的第3天开始显著促进猪BMSCs增殖。HE染色显示BMSCs在根片表面附着良好。扫描电镜观察表明实验组附着生长的BMSCs数量较多,与对照组相比具有显著差异。结论:EMPs在200μg/ml浓度时可显著促进猪BMSCs增殖,并促进其在根面的附着生长,提示EMPs和BMSCs可以联合应用以修复牙周组织缺损。     

Initial attachment of osteoblasts to various guided bone regeneration membranes: an in vitro study

OBJECTIVE AND BACKGROUND: Guided bone regeneration (GBR) has proved to be a suitable and somehow predictable technique for promoting bone regeneration. A variety of synthetic and naturally derived GBR barriers have been used in clinics to facilitate bone regeneration. These barriers may differ in composition and structure and these may affect the outcomes of GBR. Therefore, the present study was undertaken to evaluate the in vitro ability of osteoblasts (MC3T3-E1) to attach to various GBR membranes. MATERIALS AND METHODS: Six GBR/GTR (guided tissue regeneration) membranes [BioMend (BM), Resolut (RL), Guidor (GD), EpiGuide (EG), Gore-Tex (GT) and Millipore filter (MP)] were tested. For controls, cells were directly plated on culture dishes (CD). Each test membrane was secured to the bottom of a culture dish with a double-sided adhesive tape. All samples were triplicate. At 1.5 and 24 h after plating of 2 ml (5 x 10(4) cells/ml) of MC3T3-E1 (passage 7) cells, the specimens were rinsed with phosphate-buffered saline to wash out any unattached cells and then fixed with a 10% buffered formalin solution for 1 d. After washing with distilled water, the cells were stained with hematoxylin. The number of attached cells was counted under a light microscope equipped with an ocular-micrometer in a unit area of 0.25 mm(2) (five areas on each membrane). In addition, cell morphology attached to the membranes was evaluated under scanning electron microscope. RESULTS: Data were presented as mean +/- standard error and analyzed for statistical difference using a generalized Wilcoxon's test. Cell attachment at 1.5 h was as follows: MP (27.5 +/- 2.1) > RL (17.0 +/- 1.4) approximately equals BM (14.5 +/- 1.4) approximately equals EG (11.4 +/- 1.0) > GD (5.2 +/- 0.8) approximately equals GT (3.1 +/- 0.6); and at 24 h was: MP (67.6 +/- 3.6) > RL (35.8 +/- 1.8) > BM (15.4 +/- 0.9) approximately equals EG (13.3 +/- 1.3) > GD (5.9 +/- 0.7) approximately equals GT (5.6 +/- 1.3). At 24 h, the scanning electron microscope finding revealed that cells attached on MP, RL, BM and EG were flatter in shape, like cells on CD, than cells on GD and GT, where cells were rather round. CONCLUSIONS: Results from this study suggested that MP, BM, RL and EG enhanced the early osteoblast attachment. However, the true benefit of this observation in clinic remains to be determined.