Effects of diode and Nd:YAG laser irradiation on titanium discs: a scanning electron microscope examination

BACKGROUND: Dental lasers have been recommended for uncovering submerged implants as well as decontaminating implant surfaces when treating peri-implantitis. The aim of this study was to show the possible alterations in titanium disc surfaces using an Nd:YAG or a diode laser. METHODS: Three different titanium discs were used (sandblasted, titanium plasma-sprayed [TPS], and hydroxyapatite [HA] coated) to determine the effects of laser irradiation on these surfaces using a scanning electron microscope (SEM). The discs were either irradiated with a pulsed Nd:YAG laser with a contact handpiece and power settings of 2.0, 4.0, and 6.0 W or with a diode laser at 5.0, 10.0, and 15.0 W power settings and continuous wave (cw) in the contact handpiece. Irradiated areas were compared with control titanium sites which were not lased. The specimens were prepared for SEM examination after the disc irradiation. RESULTS: The SEM examination demonstrated extensive melting in all of the Nd:YAG laser irradiated areas. Damage was seen in all TPS- and HA-coated discs even at the lowest power setting. Loss of porosity, coating microfractures, and a relatively smooth surface were observed. In contrast, the diode laser did not cause any damage or modify the disc surface. Regardless of the power setting, there was no visible difference between lased and non-lased surfaces after cw irradiation with the diode laser. CONCLUSIONS: From these findings, it was concluded that the diode laser (980 nm) does not damage titanium surfaces, which should be of value when uncovering submerged implants and treating peri-implantitis.     

脉冲Nd：YAG激光照射对牙本质通透性的影响

本实验用不同能量参数的脉冲Ｎｄ：ＹＡＧ激光；分别照射牙本质窝洞底部，电镜观察和测定牙本质通透性，研究激光对牙本质的作用，初步探讨Ｎｄ：ＹＡＧ激光脱敏的机制。结果显示：０．６Ｗ（４０ｍＪ、１５Ｈｚ）组的牙本质通透性与对照组无统计学差异；０．９Ｗ（６０ｍＪ、１５Ｈｚ）和１．２Ｗ（８０ｍＪ，１５Ｈｚ）组的牙本质通透性明显增加。ＳＥＭ示所有激光组牙本质融熔、牙本质小管口模糊不清，洞底小管口部分被融熔物质阻塞。提示Ｎｄ：ＹＡＧ激光脱敏，可能存在其他的生物学脱敏机制。     

Titanium deposition after peri-implant care with the carbon dioxide laser

PURPOSE: Titanium endosseous implants are becoming increasingly important in dentistry because of their excellent long-term results. However, it has been reported that these implants may lead to higher concentrations of titanium, especially in the lungs and kidneys. The purpose of this study, therefore, was to determine whether CO2 laser-assisted decontamination of exposed implant surfaces is associated with an increase in titanium release. MATERIALS AND METHODS: In 6 beagle dogs, a total of 60 implants were placed. After osseointegration and second-stage surgery, peri-implantitis was induced by cotton floss ligatures for 12 weeks. Surgical treatment consisted of granulation tissue removal, including decontamination of the implant surface with 3 different methods. Twenty implants were decontaminated conventionally by an air-powder abrasive for 60 seconds. Another 20 implants were decontaminated by laser treatment alone. The last 20 implants were treated conventionally by air-powder abrasive and then lased. Four months later, fresh tissue samples of various tissues were evaluated by histologic and chemical analysis. RESULTS: Quantitative analysis indicated that titanium accumulation could be detected, especially in the spleen, liver, oral mucosa, regional lymph nodes, lung, and kidney in the beagle dog model. DISCUSSION: The concentrations found did not exceed those previously reported in the literature. CONCLUSION: These results support the hypothesis that CO2 laser-assisted therapy of ailing implants will not result in excessive titanium concentrations in tissues. Accordingly, CO2 lasers appear suitable and safe for peri-implant gingival surgery.     

不同表面形态种植体与种植体周围炎的相关性

目的初步探讨不同表面形态的种植体与种植体周围炎发病的相关性,为进一步寻找一种更有利于种植义齿长期稳定性的种植体表面形态设计奠定基础。方法对2307例（3652枚）种植体进行追踪观察0．5～10年．分析比较不同表面形态种植体之间种植体周围炎的发病率．考虑患者年龄、性别,种植体长度因素。结果发生种植体周围炎35例,发生率0．96％。其中负重前发生种植体周围炎26例,负重后发生种植体周围炎9例。大颗粒喷砂酸蚀（SLA）表面、钛易耐（TiUnite）表面及可吸收性喷砂介质（RBM）表面形态的种植体其种植体周围炎发生率明显低于光滑表面形态的种植体．差异具有统计学意义（P=0．02）。年龄和性别对于种植体周围炎发生率的影响差异无统计学意义（X^2=2．97,P=0．08）。10～12mm种植体显示出了更高的种植体周围炎发生率。结论在可能的情况下,尽量选择粗糙表面形态的种植体;年龄、性别对种植体周围炎的发生无明显相关性：目前的研究并不能认为种植体的长度与种植体周围炎的发生具有相关性。     

Effect of Nd:YAG, Ho:YAG, Er:YAG, CO2, and GaAIAs laser irradiation on surface properties of endosseous dental implants

PURPOSE: To analyze potential surface alterations in endosseous dental implants induced by irradiation with common dental lasers. MATERIALS AND METHODS: Sandblasted and acid-etched, plasma-sprayed, hydroxyapatite-coated, and smooth titanium discs were irradiated using Nd:YAG, Ho:YAG, Er:YAG, CO2, and GaAIAs lasers at various power settings. The specimens were examined by scanning electron microscopy and energy dispersive spectroscopy. Results: In an energy-dependent manner, the pulsed YAG lasers induced partial melting, cracking, and crater formation on all 4 surfaces. Within the energy range applied, the CO2 laser caused surface alterations on the hydroxyapatite and plasma coatings as well as in the acid-etched surface. GaAIAs laser irradiation did not damage any of the surfaces. Energy dispersive spectroscopy revealed an altered chemical compound of the surfaces with regard to titanium, oxygen, and silicon. DISCUSSION: The clinical application of most common dental laser systems can induce implant surface alterations. Relevant factors are not only the laser system and power setting, but also the application system. CONCLUSION: The results of the study indicate that Nd:YAG and Ho:YAG lasers are not suitable for use in decontamination of implant surfaces, irrespective of the power output. With the Er:YAG and CO2 laser, the power output must be limited so as to avoid surface damage. The GaAIAs laser seems to be safe as far as possible surface alterations are concerned.     

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.     

Nd��YAG�����������ֲ�����ṹ���¶ȵ�Ӱ���о�

??Objective     To investigate the effect of irradiation with Nd??YAG laser on the surface microstructure and temperature change of dental implants in vitro??in order to provide the reference for clinical parameter setting and operation method. Methods    The titanium discs were irradiated by Nd??YAG laser with different parameter setting. The surface microstructure was observed by scanning electron microscope?? and the temperature elevation was measured by thermocouple. The time to reach a 10?? increase in temperature was recorded as well. Results    ??1??Local areas with surface melting on 0.2W ??20 mJ??10 Hz??and significant melting with crackson 1W setting ??100 mJ??10 Hz or 50 mJ??20 Hz?? were observed after Nd??YAG laser irradiation without cooling??while the surface of the titanium disk is still molten with water vapor cooling.??2??The temperature elevation of titanium discs were less than 10?? with low power setting or water cooling conditions of Nd??YAG laser irradiation for 30 seconds. It took 13.8??6.2 and 7.8 seconds??respectively??to reach a 10?? increase threshold in temperature after being irradiated with 0.5 W ??50 mJ??10 Hz??and 1W??100 mJ??10 Hz or 50 mJ??20 Hz??without cooling conditions. Conclusion    Direct and prolonged exposure to Nd:YAG laser leads to microstructure change of implant surface??and may produce a risk of thermal damage to surrounding tissue. The reasonable parameter setting??mobile radiation mode and cooling are suggested.     

Heat generation by superpulsed CO2 lasers on plasma-sprayed titanium implants: an in vitro study.

OBJECTIVE: The purpose of this study was to record the generation of heat in selected titanium implants while exposing them to a superpulsed CO(2) laser mode. These results can be compared with previous studies in which continuous and pulsed CO(2) laser modes were used. STUDY DESIGN: Titanium implants with cover screws were used in this study. The length of exposure time ranged from 2 to 15 seconds, and the wattage ranged from 3 to 15 W. A thermocoupler with a module recorder was used to record temperature changes at the implant-cover screw interface with the implant in a 37 degrees C water bath. Temperature changes were documented during the exposure phase, as well as after termination of the exposure. Statistical analysis consisted of analysis of variance (P <.05) for statistically significant differences among the exposure time-wattage pairs. RESULTS: Temperature increases were directly related to wattage and exposure time. All temperatures returned to baseline within 1 minute. CONCLUSION: Superpulsed CO(2) lasers generate significantly less heat with the 15-second, 15-W trial as compared with continuous and pulsed laser modes. Peak temperature increases with similar exposure and wattage times are comparable to those of the pulsed-laser mode.     

A comparison of the morphological changes after Nd-YAG and CO2 laser irradiation of dentin surfaces

The purpose of this study was to compare the morphological changes after Nd-YAG and CO2 laser irradiation on dentin surfaces with or without the smear layer. Eighty-one 3-mm-thick dentin specimens collected from the middle third of molar crowns were used. The dentin surfaces were ground to #320, #400, and #600 grit in series to create a smear layer. Half of the specimens were treated with 14% EDTA for 2 min to remove the smear layers. The lasers were applied on each specimen perpendicularly with 1-mm focus distance to the dentin surface for 4 s. The parameters for the Nd-YAG laser were 50 mJ, 100 mJ, and 150 mJ at 10 pps, 20 pps, and 30 pps, and for the CO2 laser were 2 W, 3 W, and 4 W at 5 ms x 20 pps, 10 ms x 10 pps, 20 ms x 20 pps, 50 ms x 2 pps, 100 ms x 2 pps, and 200 ms x 2 pps. The results showed that the Nd-YAG laser caused crater and melting of the dentin surface, especially in dentin specimens with smear layers. The CO2 laser produced extensive cracking lines on dentin surfaces with a smear layer, whereas surface erosion and crater formation were found on specimens without a smear layer. In conclusion, both the laser types and smear layer have a significant influence on the morphological changes of dentin surfaces irradiated by lasers.     

Ex vivo study of the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG and Nd : YAG lasers

AIM: To evaluate the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG or Nd : YAG laser at various parameters. METHODOLOGY: Ninety maxillary canine teeth were sectioned transversely at the cemento-enamel junction and at the root tip to leave an 8-mm-long cylinder. The tooth specimen was centred in a metallic ring (16 mm diameter and 8 mm height) and embedded in acrylic resin. The root canals were prepared using a low-speed handpiece and a conical diamond bur, which was attached to a paralleling device. This bur was lowered to a depth previously determined by a silicone stop. Specimens were divided into nine groups: group I, dentine was treated with 2 mL of 17% EDTAC for 5 min. Groups II-V were irradiated with Er : YAG laser at the following parameters: group II - 8 Hz and 200 mJ input (120 mJ output); group III - 8 Hz and 400 mJ input (240 mJ output); group IV - 16 Hz and 200 mJ input (120 mJ output); group V - 16 Hz and 400 mJ input (240 mJ output). Groups VI-IX were irradiated with Nd : YAG laser at the following parameters: group VI - 10 Hz and 1 W input (0.4 W output); group VII - 10 Hz and 2 W input (0.8 W output); group VIII - 15 Hz and 1 W input (0.4 W output); group IX - 15 Hz and 2 W input (0.8 W output). The root canals were filled with an epoxy-based root canal sealer and submitted to a push-out test. RESULTS: Statistical analysis showed significant differences (P < 0.01) between Er : YAG and Nd : YAG laser treatments at the higher frequencies compared with 17% EDTAC. Greater adhesion values were obtained for groups IV and V (Er : YAG laser) and groups VIII and IX (Nd : YAG laser), which were statistically different from groups II and III (Er : YAG laser) and groups VI and VII (Nd : YAG laser). Treatment with only 17% EDTAC had the lowest adhesion values. CONCLUSIONS: An increase in frequency, independent of power settings, of the lasers used in this study increased adhesion of an epoxy-based root canal sealer.     

Regenerative therapy of deep peri-implant infrabony defects after CO2 laser implant surface decontamination

The treatment of a peri-implant infrabony defect is difficult because of contamination of the implant surface and adjacent tissues. This case series addresses the ability of a carbon dioxide (CO2) laser to decontaminate failing implants in 15 patients. Clinical and radiologic data are presented with regard to using the laser in combination with bone grafting and a barrier. Augmentation with autogenous bone grafting material (n = 10) or a xenogenic bone grafting material (BioOss) (n = 9) was used, and bone grafts were covered with a collagen membrane. Clinical and radiologic parameters were evaluated postoperatively. After an observation period of 27 months (+/- 17.83), almost complete bone fill in the peri-implant defect was accomplished. These preliminary clinical and radiologic findings suggest that decontamination of the implant surfaces with the CO2 laser in combination with augmentative techniques can be an effective treatment method for peri-implantitis.     

脉冲Nd:YAG激光影响复合树脂修补烤瓷粘接强度实验研究

目的：评价激光进行瓷面处理对复合树脂修补烤瓷的粘接效果。方法：分别用８％氢氟酸及３组能量参数的脉冲Ｎｄ：ＹＡＧ激光（１５Ｈｚ、４０ｍＪ、０．６Ｗ;１５Ｈｚ、６０ｍＪ、０．９Ｗ;１５Ｈｚ、８０ｍＪ、１．２Ｗ）对烤瓷牙粘接表面进行照射,照射时间均为１ｍｉｎ,涂硅烷液及活化剂后,粘接复合树脂。应用电子万能试验机测试复合树脂－烤瓷的抗剪切粘接强度。采用扫描电镜观察瓷处理面的形貌特征。结果：激光０．６Ｗ组、０．９Ｗ组、１．２Ｗ组及酸蚀组的抗剪切粘接强度分别为８．６１、１４．０７、１１．２２及１３．４７ＭＰａ,激光０．６Ｗ组明显低于酸蚀组,两者具有统计学差异,而０．９Ｗ组及１．２Ｗ组与酸蚀组则无显著性差异。扫描电镜显示经激光处理的瓷面粗糙不平,呈浅凹状及火山口状结构。结论：在适当能量参数下,脉冲Ｎｄ：ＹＡＧ激光可代替酸蚀进     

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.     

CO2, ER:YAG AND ND:YAG LASERS IN ENDODONTIC SURGERY

Objectives:

CO₂, Er:YAG and Nd:YAG lasers have been used in endodontic surgery. This in vitro study evaluated 1% Rhodamine B dye penetration using computer-assisted morphometry (ImageTool Software®) of 108 endodontically treated human permanent canines.

Material and methods:

Teeth were divided into 9 groups according to the technique used: A: 90-degree apicoectomy with bur, root-end cavity preparation with ultrasound and filled with MTA; B: 90-degree apicoectomy with bur, root-end cavity prepared with ultrasound and filled with MTA, and treatment of apical surface with CO₂ laser (1 W, CW/CW); C: 90-degree apicoectomy with bur, and treatment of apical surface with Nd:YAG laser (150 mJ, 10 Hz); D: 90-degree apicoectomy with bur, and treatment of apical surface with CO₂ laser (1 W, CW/CW); E: apicoectomy with Er:YAG laser (400 mJ, 10 Hz), root-end cavity prepared with ultrasound and filled with MTA; F: apicoectomy with Er:YAG laser (400 mJ, 10 Hz) and treatment of apical surface with Nd:YAG laser (150 mJ, 10Hz); G: apicoectomy with CO₂ laser (5W, CW/SP), root-end cavity prepared with ultrasound and filled with MTA; H: irradiation of apical end with CO₂ laser (1 W, CW/CW); I: irradiation of apical end with Nd:YAG laser (150 mJ, 10 Hz).

Results:

Dye penetration was found in all specimens at different rates, the lowest penetration occurring in groups C (16.20%), B (17.24%) and F (17.84%).

Conclusions:

Groups B, C and F represent the best technical sequences to perform endodontic surgery.     

Lasers in dentistry

Clinical lasers are of two types; soft lasers are essentially an aid to healing with relatively few rigorous studies available to support their use. Surgical hard lasers, however, can cut both hard and soft tissues and replace the scalpel and drill in many areas. From initial experiments with the ruby laser most clinicians are using Argon, CO2 and now NdYAG systems. The first dental laser based on a NdYAG engine provides handpieces of similar size to conventional instrumentation and, being fed by a fibre-optic 'cable', has the flexibility for intra-oral use that the CO2 lasers, widely used in oral surgery, lack. Furthermore, extensive clinical investigation has demonstrated their safety in clinical practice and the fact that procedures can usually be performed without a local anaesthetic is obviously seen as a considerable advantage by patients. Sterilising as it cuts, the NdYAG laser promises to find uses not only in caries removal and soft tissue surgery, but also in endodontics and gingival curettage.     

Scanning electron microscopy and Fourier transformed infrared spectroscopy analysis of bone removal using Er:YAG and CO2 lasers

BACKGROUND: A thorough analysis of laser-ablated bone tissue is required before applying the technique to osseous surgery. In this study, we examine the morphological features and chemical composition of the bone surface after Er:YAG and CO2 lasers ablation. METHODS: Six Wistar rats were used. An Er:YAG laser was used for ablation at an output energy of 100 mJ/pulse and a pulse rate of 10 Hz (1 W). Continuous CO2 laser irradiation was performed at an output energy of 1 W. Sites drilled using a conventional micromotor were used as controls. Analysis using scanning electron microscopy (SEM) and Fourier transformed infrared (FTIR) spectroscopy was performed. RESULTS: Er:YAG laser ablation produced a groove with similar dimensions to that produced by bur drilling, whereas the CO2 laser produced only a charred line with minimal tissue removal. SEM observations revealed that the groove produced by the Er:YAG laser had well-defined edges and a smear layer-free surface with a characteristically rough appearance and with entrapped fibrin-like tissue. The melting and carbonization produced by the CO2 laser were not observed on sites irradiated by the Er:YAG laser. FTIR spectroscopy revealed that the chemical composition of the bone surface after Er:YAG laser ablation was much the same as that following bur drilling. The production of toxic substances that occurred after CO2 laser irradiation was not observed following Er:YAG laser irradiation or bur drilling. CONCLUSION: These results suggest that the use of Er:YAG laser ablation may become an alternative method for oral and periodontal osseous surgery.     

Er:YAG laser in defocused mode for scaling of periodontally involved root surfaces: an in vitro pilot study

BACKGROUND: The Er:YAG laser may be used on periodontally involved teeth in combination with conventional periodontal therapy in order to improve the efficacy of root instrumentation. The aim of this study was to compare the effect of hand instrumentation on root surfaces of periodontally involved teeth with Er:YAG laser application. METHODS: Thirty freshly extracted, non-carious, single-rooted, periodontally diseased human teeth from adult humans with advanced periodontal disease were used in this study. The teeth were divided into three groups of 10 specimens each. Group A was treated with scaling and root planing (SRP) with curets only (control). In group B, the root surfaces were scaled with curets and then lased with an Er:YAG laser (wavelength 2.94 microm). A handpiece with a water spray was used in non-contact mode (defocused) at a distance of 1 cm from root surface. Laser parameters were set at energy of 100 to 200 mJ/pulse, with 10 Hz of frequency. In group C, the root surfaces were lased only with power settings 250 to 300 mJ/pulse and 10 Hz frequency. An epon-araldite plastic embedding technique was used for light microscopic investigation. RESULTS: Histologic findings showed significant differences between the test and control sites. In control sites, after hand instrumentation, the surface was smooth, without a cementum layer, and the dentin layer presented opened tubules. Defects on the dentin layer were also present along root surfaces. In the test sites (B, C) root surfaces revealed no thermal damage; no cracking or tissue carbonization were observed. The superficial layers of lased surfaces appeared smooth and melted without alterations. CONCLUSION: Based on these findings, it appears that it may be feasible to use the Er:YAG laser for root instrumentation without prior root planing if the proper parameters are followed.     

不同功率水冷激光对不同表面处理种植体结构影响的研究

目的:探索不同功率的水冷激光对于不同种植体表面的影响。方法:收集临床上因种植体周围炎而拔除的不同表面种植体,分别用2、3、4 W 3种不同参数的水冷激光处理,通过扫描电镜(SEM)进行观察比较。结果:SLA^?非亲水表面和INICELL^?表面3~4 W的激光处理既能很好的去污又不会造成表面损伤;Tiunite^?表面和国产MDIC种植体微弧氧化表面在2 W时去污效果欠佳,而3 W与4 W去污效果相当,4 W时会导致表面损伤。结论:随着功率的增大,水冷激光去污效果逐渐加强。不同激光参数对于不同种植体表面的影响不同,其中氧化类表面更易崩解,而喷砂酸蚀表面耐受激光的能力更强。     

Osseointegration of commercial microstructured titanium implants incorporating magnesium: a histomorphometric study in rabbit cancellous bone

Objective: Recent studies have suggested that magnesium (Mg) ions exert a beneficial effect on implant osseointegration. This study assessed the osseointegration of nanoporous titanium (Ti) surface incorporating the Mg produced by hydrothermal treatment in rabbit cancellous bone to determine whether this surface would further enhance bone healing of moderately rough‐surfaced implants in cancellous bone, and compared the result with commercially available micro‐arc oxidized Mg‐incorporated implants. Material and methods: The Mg‐incorporated Ti surfaces (RBM/Mg) were obtained by hydrothermal treatment using an alkaline Mg‐containing solution on grit‐blasted moderately rough (RBM) implants. Untreated RBM and recently introduced Mg‐incorporated microporous Ti implants produced by micro‐arc oxidation (M) were used controls in this study. The surface characteristics were evaluated by scanning electron microscopy, X‐ray photoelectron spectroscopy and optical profilometry. Twenty‐four threaded implants with a length of 10 mm (eight RBM implants, eight RBM/Mg implants and eight M implants) were placed in the femoral condyles of 12 New Zealand White rabbits. Histomorphometric analysis was performed 4 weeks after implantation. Results: Hydrothermally treated and untreated grit‐blasted implants displayed almost identical surface morphologies and R_a values at the micron‐scale. The RBM/Mg implants exhibited morphological differences compared with the RBM implants at the nano‐scale, which displayed nanoporous surface structures. The Mg‐incorporated implants (RBM/Mg and M) exhibited more continuous bone apposition and a higher degree of bone‐to‐implant contact (BIC) than the untreated RBM implants in rabbit cancellous bone. The RBM/Mg implants displayed significantly greater BIC% than untreated RBM implants, both in terms of the all threads region and the total lateral length of implants (P<0.05), but no statistical differences were found between the RBM/Mg and M implants except BIC% values in total lateral length. Conclusion: These results indicate that a nanoporous Mg‐incorporated surface may be effective in enhancing the osseointegration of moderately rough grit‐blasted implants by increasing the degree of bone?implant contact in areas of cancellous bone. To cite this article :
Park J‐W, An C‐H, Jeong S‐H, Suh J‐Y. Osseointegration of commercial microstructured titanium implants incorporating magnesium: a histomorphometric study in rabbit cancellous bone.
Clin. Oral Impl. Res. 23 , 2012; 294–300.
doi: 10.1111/j.1600‐0501.2010.02144.x     

The effect of CO(2) laser irradiation on failed implant surfaces

The aim of this investigation was to evaluate the cleaning effect of CO(2) on surface topography and composition of failed dental implant surfaces. Ten failed dental implants were retrieved from nine patients (mean age, 46.33 +/- 5.81 years) as a result of early or late failure. The implants were divided into two parts: one side of the implant was irradiated with a CO(2) laser (test side), while the other side did not receive irradiation (control side). The CO(2) laser was operated at 1.2 W in a continuous wave for 40 seconds (40 J energy). The handpiece of the CO(2) laser was kept at a distance of 30 mm from the implant surface, resulting in a spot area of 0.031415 cm (38.20 W/cm; 1559 J/cm) in scanning mode (cervical-apical). One unused dental implant was used as a negative control for both groups. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) for element analysis. SEM showed that the surface of the test sides consisted of different degrees of organic residues, appearing mainly as dark stains similar to those observed on the control sides. None of the test surfaces presented alterations such as crater-like alterations, lava-like layers, or melting compared with the nonirradiated surfaces. Foreign elements such as carbon, oxygen, sodium, calcium, and aluminum were detected on both sides. These results suggest that CO(2) laser irradiation does not modify the implant surface, although the cleaning effect was not satisfactory.