Per-implant care of ailing implants with the carbon dioxide laser.

One of the many applications for which lasers have been proposed in implant dentistry is for the decontamination process. The purposes of this study were to assess possible alterations in titanium implants in vitro and in vivo by use of the carbon dioxide (CO2) laser and to determine whether new bone formation can occur on previously contaminated implants. In vitro, temperature changes at the bone-titanium implant interface were recorded during use of a CO2 laser-scanning system (Swiftlase). Additionally, the effects of laser irradiation on titanium implants at various power settings were examined. In 6 beagle dogs, a total of 60 implants and bony defects resulting from plaque accumulation were treated by air-powder abrasive (the conventional treatment), laser irradiation, or both. Depending on the parameters chosen, melting and other surface alterations were seen in vitro, especially in the superpulse mode. Otherwise, no alterations were found, even at high power settings in the continuous mode. In vivo, corresponding histologic examination of 4-month sections showed evidence of new direct bone-to-implant contact after laser-assisted therapy, especially when the implants had been treated concomitantly with submerged membranes. These results support the hypothesis that peri-implant defects can be treated successfully by laser decontamination without damaging the surrounding tissues in the dog model. Nevertheless, further investigations will be required to determine the clinical efficacy of the treatment.     

Conventional versus CO2 laser-assisted treatment of peri-implant defects with the concomitant use of pure-phase beta-tricalcium phosphate: a 5-year clinical report

PURPOSE: Recently, histologic studies in the beagle dog model demonstrated that CO2 laser-assisted implant decontamination can result in reosseointegration. Consequently, the purpose of this study was to assess the efficacy of CO2 laser-assisted therapy as compared with conventional therapy, with the concomitant use of beta-tricalcium phosphate, in humans. MATERIALS AND METHODS: The study included 32 patients with 73 ailing implants. In the laser group, 22 implants were treated with soft tissue resection following laser decontamination; whereas in 17 implants, bone augmentation was performed. In the control group, soft tissue resection after conventional decontamination was performed in 19 implants, augmentation in 15 implants. Results were evaluated 4 months after surgery and in May 2004. RESULTS: Four months after therapy, there were no significant differences in distance from implant shoulder to the first bone contact (ie, DIB values) between implants undergoing laser decontamination and soft tissue resection and implants treated with conventional decontamination followed by soft tissue resection. At the end of the study, there was a statistically significant difference between these 2 groups. Four months after therapy, DIB values after laser decontamination and augmentation were significantly more favorable than after conventional decontamination and augmentation. This difference was no longer detectable at the end of the study. CONCLUSION: Based on the results of this study, it may be concluded that the treatment of peri-implantitis may be accelerated by using a CO2 laser concomitant with soft tissue resection. However, with respect to long-term results in augmented defects, there seems to be no difference between laser and conventional decontamination.     

Bone regeneration after peri-implant care with the CO2 laser: a fluorescence microscopy study

PURPOSE: The carbon dioxide (CO2) laser has been shown to be suitable for the treatment of ailing implants. However, comparatively little is known about bone regeneration after laser treatment. Therefore, the purpose of this study was to determine the course of bone regeneration after peri-implant care with the CO2 laser. MATERIALS AND METHODS: In 6 beagle dogs, a total of 60 implants and bony defects were treated either conventionally by air-powder abrasive (group 1), by laser irradiation alone (group 2), or by a combination of the 2 (group 3). After therapy, polychrome sequence labeling was performed using 4 different markers. Four months later, after sacrifice, histologic sections were photographed and scanned. In each specimen, the 4 stained areas were detected with special software and indicated as a percentage of the standardized measurement frame. Lastly, the time-course of the bone regeneration was determined for each of the 3 therapy groups. RESULTS: Fluorescence microscopy demonstrated maximum bone regeneration after 8 weeks in all 3 therapy groups. In this period, groups 2 and 3 showed significantly greater amounts of newly formed bone than group 1 (P < .03 and P < .05, respectively). However, there was no difference in bone regeneration between groups 2 and 3. DISCUSSION: Using fluoresence microscopy, it was possible to analyze and interpret the bone regeneration processes during all 4 application phases of the 3 groups. CONCLUSIONS: These results support the hypothesis that CO2 laser irradiation renders significantly more new bone formation, especially 5 to 8 weeks postoperatively, than conventional decontamination in the dog model. Further investigation will be required to determine the clinical efficacy.     

Effects of an air-powder abrasive system on plasma-sprayed titanium implant surfaces: an in vitro evaluation

The purpose of this study was to conduct an in vitro evaluation of the effects of an air-powder abrasive system, commonly used in clinical dentistry for periodontal maintenance, on the surfaces of plasma-sprayed titanium dental implants. Twenty-eight plasma-coated titanium implant specimens were divided into a sterile water-treated control group and an air-powder-abrasive-treated test group. All specimens were subjected to three different in vitro testing conditions and post-treatment evaluations by scanning electron microscopy (SEM): (1) Topographical features of implant surfaces were studied before and after direct exposure to the abrasive; (2) biocompatibility of treated implant surfaces was evaluated and compared with those of control specimens via in vitro fibroblast attachment studies; and (3) the attachment of a common oral microbe to the implant surface and its subsequent removal by exposure to the air-powder abrasive were also evaluated. Results indicate that exposure of implant specimens to the air-powder abrasive for various periods resulted in only slight changes in surface topography, i.e., rounding of angles and edges of the plasma-spray coating and occasional surface pitting. Examination by SEM and a statistical comparison of the difference between the mean numbers of attached fibroblasts between control and test groups revealed no statistical significance. In both specimen groups, fibroblasts exhibited uniform attachment over the entire implant surface. A comparison of test and control groups demonstrated 100% removal of bacteria from the surfaces of test specimens exposed to the air-powder abrasive and approximately a 75% removal from control specimens exposed to sterile water.     

The effect of a decontamination protocol on contaminated titanium dental implant surfaces with different surface topography in edentulous patients

Objectives: To investigate if it is possible to achieve complete decontamination of dental implant surfaces with different surface characteristics.

Materials and methods: Twelve implant pieces with an Osseotite^® surface and 12 implant pieces with a Ti-Unite^® surface were attached on to the complete lower dentures of six patients and were allowed to accumulate plaque for 30 days. When retrieved, the implant decontamination protocol used, involved both mechanical (PeriBrush?) and chemical (3% H₂O₂) decontamination. The number of colony forming units per millilitre was determined and the dominant micro-organisms in selected samples was identified by 16s rRNA gene amplicon sequencing. The effect of the titanium brush on the implant surface was examined by SEM.

Results: Complete decontamination was achieved in five out of 24 implants (four Osseotite^® and one Ti-Unite^®). The mean CFU/ml detected after decontamination were 464.48 for Osseotite^® and 729.09 for Ti-Unite^® implants. On the surface of the implants in which complete decontamination was not achieved, all of the predominant bacteria identified were streptococci except for one which was identified as micrococcus. SEM images revealed that the surface features of the decontaminated implants were not significantly altered.

Conclusions: Mechanical decontamination using a titanium brush supplemented with chemical treatment for one minute (3% H₂O₂) can achieve complete decontamination of implant surfaces in edentulous patients.     

Detoxification of endotoxin-contaminated titanium and hydroxyapatite-coated surfaces utilizing various chemotherapeutic and mechanical modalities.

The surgical repair of the ailing implant may be complicated by the surface effects of pathogenic bacteria and their products. This study evaluated the ability of various chemotherapeutic modalities to detoxify endotoxin-contaminated titanium alloy and hydroxyapatite-coated test strips. Grit-blasted titanium alloy and hydroxyapatite-coated test strips were contaminated with purified outer membranes of Escherichia coli labeled with radioactive 14C. The titanium alloy strips were treated with citric acid, stannous fluoride, tetracycline HCl, chlorhexidine gluconate, hydrogen peroxide, chloramine T, sterile water, a plastic sonic scaler tip, and an air-powder abrasive unit. Hydroxyapatite-coated strips were treated with chloramine T, citric acid, or burnished with sterile water on cotton pellets. Residual lipopolysaccharide levels were measured by liquid scintillation spectrometry. The air-powder abrasive unit removed significantly greater amounts of lipopolysaccharide than all other treatment modalities on titanium samples (P < 0.05). A 60-second burnish with sterile water was able to remove significant amounts of lipopolysaccharide when compared with untreated controls (P < 0.05). Citric acid was superior in the removal of lipopolysaccharide from hydroxyapatite-coated surfaces when compared with the controls or chloramine T (P < 0.01). Detoxification of an implant infected surface may be beneficial when surgical repair of the ailing implant is indicated.     

Antimicrobial Agents Used in the Treatment of Peri‐Implantitis Alter the Physicochemistry and Cytocompatibility of Titanium Surfaces

Background: Chemotherapeutic agents (ChAs) are considered an integral part of current treatment protocols for the decontamination of titanium implants with peri‐implantitis, based on their antimicrobial effect. Despite the proven antimicrobial effect of ChAs on titanium‐bound biofilms, previous studies have elucidated an unexpected disassociation between bacterial reduction and biologically acceptable treatment outcomes. In this study, the authors hypothesize that ChAs residues alter titanium physicochemistry and thus compromise cellular response to decontaminated surfaces. Methods: Grit‐blasted acid‐etched titanium disks were contaminated with multispecies microcosm biofilms grown from in vivo peri‐implant plaque samples. To simulate implant decontamination, the contaminated disks were burnished with 0.12% chlorhexidine, 20% citric acid, 24% EDTA/1.5% NaOCl, or sterile saline and assessed surface physicochemical properties. Sterile untreated surfaces were the controls. The biologic effects of decontamination were assessed via cell proliferation and differentiation assays. Results: Bacterial counts after decontamination confirmed that the ChAs were antimicrobial. X‐ray photoelectron spectroscopy invariably detected elemental contaminants associated with each ChA molecule or salt that significantly altered wettability compared with controls. Notably, all surfaces with ChA residues showed some cytotoxic effect compared with controls (P <0.05). Increased cell counts were consistently found in the saline‐treated group compared with chlorhexidine (P = 0.03). Interestingly, no association was found between antimicrobial effect and cell counts (P >0.05). Conclusions: ChA‐specific residues left on the titanium surfaces altered titanium physical properties and adversely affected the osteoblastic response irrespective of their observed antimicrobial effect. Chlorhexidine may compromise the biocompatibility of titanium surfaces, and its use is not recommended to detoxify implants. Sterile saline, citric acid, and NaOCl‐EDTA may be proposed for use in the treatment of peri‐implantitis. Contrary to previous studies that recommended the selection of ChAs for the decontamination of titanium implants according to their antimicrobial effects, the present study demonstrated that the restoration of the biocompatibility of contaminated titanium surfaces is also contingent on the preservation of titanium material properties.     

Implant surface preparation in the surgical treatment of experimental peri-implantitis with autogenous bone graft and ePTFE membrane in cynomolgus monkeys

The aim of the present investigation was to assess the effect of four implant surface preparation methods used in the surgical treatment of experimental peri-implantitis with autogenous bone graft and expanded polytetrafluoroethylene (ePTFE) membrane. The methods were air-powder abrasive unit+citric acid, air-powder abrasive unit, gauze soaked in saline+citric acid, and gauze soaked alternately in chlorhexidine and saline. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was placed in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month period with plaque control, experimental peri-implantitis was induced. A bone loss of 4-6 mm was established after 9-17 months and plaque control was re-implemented. The peri-implantitis defects were surgically exposed, granulation tissue was removed, and each implant surface was prepared by one of the above-mentioned procedures. The defects were then filled with autogenous bone graft particles and covered by an ePTFE membrane. The animals were sacrificed after 6 months. Evaluation by clinical parameters, radiography including quantitative digital subtraction radiography, histology, and stereology did not reveal significant differences between the methods. Almost total bone regeneration and considerable re-osseointegration were obtained irrespective of the method applied. A mean bone-to-implant contact of 39-46% was observed within the defects. Therefore, the present study of implants with a TPS surface in cynomolgus monkeys indicates that the simplest method involving gauze soaked alternately in chlorhexidine and saline should be the preferred implant surface preparation method in the surgical treatment of peri-implantitis involving autogenous bone graft and ePTFE membrane.     

Influence of different implant surfaces on peri-implant osteogenesis: histomorphometric analysis in sheep

BACKGROUND: The present study investigated peri-implant osteogenesis and implant biologic fixation in different zirconia sandblasted endosseous titanium surfaces (SLA-60 and SLA-120) and a turned titanium surface (T) 2 and 4 weeks after surgery. METHODS: Seventy-two implant screws were implanted in tibia of six sheep. Histologic sections of implants (2 and 4 weeks after surgery) were analyzed with light microscopy for histomorphometric analysis of bone-to-implant contact (BIC), bone ingrowth (BI), and bone surface (BS/BV). Histologic blocks were used to perform bone microhardness studies next to the implants. Some implants were also observed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). RESULTS: In general, the highest values of BIC, BI, BS/BV, and Vickers hardness number (HV) were measured in SLA-60 samples, followed by SLA-120 and T implants. Two weeks after surgery, all the implants appeared biologically fixed by a newly formed woven bone arranged in thin bone trabeculae and filling the gap between implant and host bone. Four weeks after implantation, the thickness of the woven bone trabeculae had increased, especially around the SLA-60 and SLA-120 implants by a gradual deposition of parallel-fiber bone. CONCLUSIONS: Our results suggest that, in the early period of peri-implant healing, the implant surface morphology that seemed to influence the increase of peri-implant osteogenesis, bone turnover, and peri-implant bone maturation was SLA-60. We suggest that this surface, characterized by moderately deep titanium cavities very similar to the osteocyte lacunae, could act as a microscopic scaffold for mesenchymal and/or osteoblast-like cells adhesion.     

Comparison of healed tissues adjacent to submerged and non‐submerged unloaded titanium dental implants. A histometric study in beagle dogs.

This study involved histometry of the healed tissues around submerged and nonsubmerged dental implants in beagle dogs. In a split‐mouth design, 19 submerged and 19 nonsubmerged commercially pure titanium implants, titanium plasma‐sprayed in the bone anchoring part and smooth in the transmucosal portion were placed in the mandibles of 6 dogs. Oral hygiene was performed 3 times weekly. After 3 months of healing, transmucosal abutments were inserted in the submerged implants. Six weeks after second stage surgery, the dogs were sacrificed and specimens obtained and processed for histology and histometry. Using a light microscope and a digitizing pad, the distance from implant top to mucosa border (DIM), the extent of epithelial downgrowth (ED), the attachment level (AL). the length of connective tissue contact (CTC) and the distance of the first coronal alveolar bone contact from the implant top (DIB) were measured at the mesial and distal aspects. Means+standard deviations for submerged and nonsubmerged implants were calculated, with the dog being the unit of measure. No statistically significant differences between submerged and nonsubmerged implants here found for DIM, CTC and DIB. However, significant differences were observed for ED and AL. This study in beagle dogs indicates that the apical extension of the peri‐implant epithelium is significantly greater and the attachment level significantly lower adjacent to submerged implants with second‐stage transmucosal abutments than in nonsubmerged, one‐stage implants.     

Decontamination of Anodized Implant Surface With Different Modalities for Peri‐Implantitis Treatment: Lasers and Mechanical Debridement With Citric Acid

Background: Although oral rehabilitation with dental implants is a very promising and effective procedure, peri‐implantitis is an emerging concern. Surgical and non‐surgical methods have been applied to treat peri‐implantitis together with various implant surface decontamination methods. However, there is no consensus concerning the most effective treatment for peri‐implantitis. The aim of the present study is to evaluate the effects of erbium‐doped:yttrium, aluminum, and garnet (Er:YAG) laser, photodynamic therapy (PDT), and titanium bur with and without citric acid on ligature‐induced peri‐implantitis around an anodized implant surface. Methods: Thirty dental implants with anodized surface (3.3 × 10 mm) were installed in the mandibles of five beagle dogs. After 3 months, peri‐implantitis was induced by applying cotton ligatures subgingivally. After ligature removal (baseline), the implants were divided into the following treatment groups: 1) Er:YAG laser, 2) PDT, 3) titanium bur alone, and 4) titanium bur with citric acid. Animals were sacrificed after 3 months, and clinical, radiologic, histologic, and histomorphometric evaluations were conducted for all treatment modalities. The data were analyzed using one‐way analysis of variance and Tukey test. A value of P <0.05 was considered statistically significant. Results: The titanium bur with citric acid group exhibited statistically significantly greater improvement in vertical bone height than the Er:YAG laser group and significantly better bone‐to‐implant contact than the PDT group and the bur‐alone group. Conclusion: Within the limits of the study, the combination of mechanical and chemical treatment proved to be the most effective treatment for disinfection of the anodized implant surface.     

不同去污方法对种植体表面处理的体外研究

目的    评估不同去污方法对污染种植体的清洁效果和表面形态的影响，为临床中种植体表面清洁方案的选择提供依据。方法　研究样本为收集自重度种植体周炎病例的8颗离体种植体，随机分为4组，每组2颗种植体，分别使用钛刮治器（刮治组）、钛刷（钛刷组）、喷砂（喷砂组）和铒激光（激光组）对种植体表面进行清洁并记录清洁时长，使用扫描电镜和X射线能谱仪对种植体表面进行成像和元素分析。结果     清洁效果：①刮治组、钛刷组和喷砂组的组间清洁时长差异无统计学意义（均P > 0.05），激光组用时明显高于刮治组（P < 0.05）；②低倍电镜图显示喷砂组与钛刷组的清洁程度相当，残留沉积物明显少于刮治组，而激光组去污前后沉积物量无明显变化；③元素分析显示仅喷砂组钛元素占比明显高于刮治组和基线（P < 0.05）。表面形态：高倍电镜图显示激光去污和喷砂去污对蜂窝结构无影响，刮治组轻微改变，而钛刷组破坏严重。结论    钛刮治器清洁污染种植体的能力有限，喷砂清洁有一定优势。目前单一的机械去污仍无法实现彻底清洁，需进一步探究更有效的去污方案。     

The effect of titanium implant abutment surface irregularities on plaque accumulation in vivo.

The purpose of this study was 2-fold to: 1) evaluate in vitro the surface texture of titanium implant abutments after exposure to plastic scalers, an air-powder abrasive system, rubber cup polishing with flour of pumice, and untreated control abutments; and 2) compare plaque accumulation in humans on abutments treated with the above methods. In part I, 5.5 mm abutments were instrumented for 30 seconds per 90 degrees segment with the respective methods. The surface character was compared to untreated controls using SEM at 260X magnification. The control abutments revealed prominent milling marks and small pits; plastic scalers slightly smoothed the milling marks and created microscratches; the air-powder abrasive largely obliterated the milling marks and caused some surface pitting; the rubber cup with flour of pumice removed the milling marks and created a smooth swirl pattern. None of the instrumentation appeared to roughen the surface. In the clinical experiment (part II), four abutments, one of each type, were placed in 12 patients for a period of 7 days, during which the patients performed no oral hygiene. At the end of 7 days, the abutments were retrieved and processed for SEM. A digitizer and software program were used to determine the percent of total abutment surface area covered by plaque. The demarcation of supragingival and subgingival plaque was well delineated. The total mean percent surface area of plaque ranged from 52.06% for the air-powder abrasive to 55.29% for the plastic scalers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Peri-implant hard and soft tissue integration to dental implants made of titanium and gold

OBJECTIVES: The aim of the study is to compare the peri-implant hard and soft tissue integration around dental implants made of commercially pure (c.p.) titanium or a gold alloy but with the same shape and surface roughness. MATERIAL AND METHODS: In four beagle dogs, all mandibular premolars were extracted. Three months later, four experimental non-submerged implants were placed in each edentulous premolar region. Each implant comprised three different zones: zone A (coronal), zone B (central) and zone C (apical). Each zone was made of either c.p. titanium or a gold alloy. Four different combinations of metal and zone were used. A plaque control program was initiated and 6 months later, the animals were sacrificed and biopsies were obtained. The biopsies including the implant and the surrounding tissues were processed for ground sectioning. RESULTS: The height of the peri-implant mucosa and the length of the barrier epithelium were similar at the four experimental sites. The marginal bone level in the different metal combinations was located between 4.5 and 4.8 mm apical of the implant rim. The percent of mineralized bone that was in direct contact with the implant surface (BIC%) was consistently greater in the marginal than in the apical portion of the implants. The BIC% for the marginal and apical zone were consistently greater for implant portions made of titanium than for portions made of gold alloy (zone B: 42.7% vs. 36.5%, zone C: 33.2% vs. 19%). CONCLUSIONS: Osseointegration was achieved to surfaces made of both c.p. titanium and a gold alloy. BIC% was higher at titanium than at gold surfaces. Moreover, the peri-implant soft tissue dimensions were not influenced by the metal used in the 'marginal' zone of the implant.     

Temperature increases during surface decontamination of titanium implants using CO2 laser

The purpose of the present in vitro investigation was to measure temperature changes at the implant surface when using pulsed CO2 laser in a simulated implant surface decontamination protocol. Six threaded titanium implants were placed in a fresh resected pig mandible. A 4 x 4 mm defect was created buccally to each implant in order to expose the implant head and approximately 5 threads. Temperature changes were monitored by two thermocouples placed near the dehiscence and at the apical part of the implant. Several setting combinations of the CO2 laser with regard to output power, pulse width, pulse repetition rate and irradiation time were tested on dry and wet (distilled water) surfaces. Only minor temperature increases were measured when lasing wet titanium surfaces, while the temperature at dry surfaces exceeded the proposed thresholds for bone damage at clinically relevant settings. It is concluded that the CO2 laser when used on a wet implant surface in a pulsed mode at 8 W/10 ms/20 hz during 5 s induces a temperature increase of less than 3 degrees C. This would minimize the risk of temperature induced tissue damage as a result of lasing implant surfaces.     

A histomorphometric and biomechanical study of the effect of delayed titanium implant placement in irradiated rabbit bone

Background: The time interval from irradiation to implant surgery has been considered an impact factor for implant integration in irradiated bone and the importance of a long interval between the radiation trauma and reconstructive bone surgery has been suggested. Purpose: The present study was undertaken to histomorphometrically and biomechanically analyze the effect of delayed implant placement on bone healing around titanium implants in irradiated bone. Materials and Methods: Rabbits were given a single dose of 15 Gy Cobalt⁶⁰ radiation to one hind leg, the other hind leg serving as a control. Titanium screws were inserted into the femur and tibia directly and at 12 weeks and 52 weeks after irradiation. The implants were evaluated after a healing time of 8 weeks. The torques necessary for removal of the implants were measured. Histomorphometry with respect to bone‐metal contact and amount of bone surrounding the implants was performed. Results: The biomechanical force necessary to unscrew the titanium implants in the irradiated bone was significantly increased after a resting period of 1 year between irradiation and implant placement, compared to direct implant placement. The histornorphometric evaluation showed an improvement of bone healing around the implants in the irradiated bone, both after a resting period of 12 weeks and after 1 year compared to direct implant placement. Conclusions: It is concluded that a relatively long interval between irradiation and reconstructive bone surgery will improve osseointegration of titanium implants in irradiated rabbit bone.     

显微CT与硬组织切片技术在评价牙种植体骨结合中应用的对比研究

目的 :探讨最佳反映牙种植体表面骨结合情况的检测方法。方法 :4只beagle犬下颌骨延期植入40枚种植体,在2周和4周时取样进行显微CT检测和硬组织切片制作,对比两种检测方法的效果和特点。结果:显微CT具有连续性和完整性的优势,可以宏观地观察到种植体周围骨质情况,但是由于金属伪影的存在,它对种植体-骨界面成骨现象显示不够清晰。硬组织切片是一种单层组织切片,制作过程较复杂,但其对种植体-骨界面的细微情况显示较清晰。结论:显微CT更适用于对种植体周围总体成骨的评估,而种植体表面成骨的细微变化宜采用硬组织切片。     

Effect of an air-powder abrasive system on root surfaces in periodontal surgery

The purpose of this study was to compare the effectiveness of an air-powder abrasive technique to conventional root planing during periodontal surgery. 7 patients scheduled for multiple extractions of periodontally-involved teeth were selected. Full thickness mucoperiosteal flaps were reflected, and proximal surfaces of 32 teeth were either ultrasonically scaled and exposed to the air-powder abrasive, or ultrasonically scaled and then manually root planed. Following extraction, teeth were stained for residual plaque and photographed, or prepared for scanning electron microscopy. The air-powder abrasive technique used for surgical root preparation was found to produce a root surface favorably comparable to manual root planing with regard to removal of plaque, calculus, and exposed cementum. A mean of 80 micron of cementum was abraded away after 40 s of exposure to the air-powder spray. The air-powder abrasive spray demonstrated an advantageous ability to remove plaque and cementum from areas of difficult access, such as furcations and root flutings.     

The soft tissue barrier at implants and teeth

In the present animal experiment. analyses and comparisons were made between the structure and composition of clinically healthy supraalveolar soft tissues adjacent to implants and teeth. 5 beagle dogs were used. The right mandibular premolar region was selected in each dog for placement of titanium implants. while the left mandibular premolar region served as control. Extractions of the mandibular premolars were performed. healing allowed, following which titanium fixtures were installed in the edentolous premolar region. Abutment connection was carried out 3 months later. After another 2 months of healing. plaque control was initiated and maintained for 8 weeks. At the end of the plaque control period. clinical examinations were performed and biopsies harvested from the implant site and the contralateral premolar tooth region. Following fixation and decalcification, all tissue samples were embedded in EPON and examined by histometric and morphometric means. The result from the analyses demonstrated that the peri‐implant mucosa which formed at titanium implants following abutment connection had many features in common with gingival tissue at teeth. Thus, like the gingiva. the peri‐implant mucosa established a cuff‐like barrier which adhered to the surface of the titanium abutment. Further. both the gingiva and the peri-implant mucosa had a well‐keratinized oral epithelium which was continuous with a junctional epithelium that faced the enamel or the titanium surface. In the periimplant mucosa. the collagen fibers appeared to commence at the marginal bone and were parallel with the abutment surface. All gingival and peri‐implant units examined were free from infiltrates of inflammatory cells. It was suggested that under the conditions of study. both types of soft tissues. gingiva and peri‐implant mucosa. have a proper potential to prevent subgingival I plaque formation.     

Improvement of osseointegration of titanium dental implant surfaces modified with CO ions: a comparative histomorphometric study in beagle dogs

The aim of this study was to compare carbon-oxygen (CO) ion implantation as a surface treatment with diamond-like carbon and commercially treated implants, including double acid-etched (Osseotite), oxidized (TiUnite) and sandblasted and acid-etched (SLA), using machine-turned titanium implants as control. A total of 72 dental implants divided into 6 groups were placed in the mandibles of 12 beagle dogs. Evaluation was performed by conventional light transmission microscopy and environmental scanning electron microscopy (ESEM). The histological results obtained via ESEM demonstrated bone-implant contact percentage (%BIC) for implants treated with CO ion implantation of 61% and 62% at 3 and 6 months, respectively. At the same time points, the values were 48% and 45% for double acid-etched, 46% and 52% for sandblasted and acid-etched, 55% and 46% for oxidized, and 33% and 49% for machine-turned titanium control implants. Values of %BIC were statistically significantly higher in implants treated with CO ion implantation compared to the commercially treated implant group (p=0.002 and p=0.025) and the control implants (p=0.001 and p=0.032) at 3 and 6 months, respectively. No significant differences were observed between the three groups of commercially treated implants. The larger %BIC of the ion-implanted group was observable at an early stage.