Implants

J Korean Assoc Oral Maxillofac Surg. 2016 Feb;42(1):2-8. Epub 2016 Feb 15.

Low-level laser therapy affects osseointegration in titanium implants: resonance frequency, removal torque, and histomorphometric analysis in rabbits.

Kim JR1, Kim SH2, Kim IR3, Park BS3, Kim YD4.
Author information
1Department of Oral and Maxillofacial Surgery, On General Hospital, Busan, Korea.
2Department of Oral and Maxillofacial Surgery, School of Dentistry, Pusan National University, Yangsan, Korea.
3Department of Oral Anatomy, School of Dentistry, Pusan National University, Yangsan, Korea.
4Department of Oral and Maxillofacial Surgery, School of Dentistry, Pusan National University, Yangsan, Korea.; Institute of Translational Dental Sciences and Dental Research Institute, Pusan National University Dental Hospital, Yangsan, Korea.
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Abstract
OBJECTIVES:
The purpose of this study was to investigate the effects of low-level laser therapy (LLLT) with a diode gallium-aluminum-arsenide (Ga-Al-As) low-level laser device on the healing and attachment of titanium implants in bone.
MATERIALS AND METHODS:
Thirteen New Zealand white male rabbits weighing 3.0±0.5 kg were used for this study. Dental titanium implants (3.75 mm in diameter and 8.5 mm in length, US II RBM plus fixture; Osstem, Seoul, Korea) were implanted into both femurs of each rabbit. The rabbits were randomly divided into a LLLT group and a control group. The LLLT was initiated immediately after surgery and then repeated daily for 7 consecutive days in the LLLT group. Six weeks and 12 weeks after implantation, we evaluated and compared the osseointegration of the LLLT group and control group, using histomorphometric analysis, removal torque testing, and resonance frequency analysis (RFA). The results were statistically significant when the level of probability was 0.05 or less based on a non-parametric Mann-Whitney U-test.
RESULTS:
The implant survival rate was about 96%. Histologically and histomorphometrically, we observed that the titanium implants were more strongly attached in LLLT group than in control group. However, there was no significant difference between the LLLT group and control group in removal torque or RFA.
CONCLUSION:
Histologically, LLLT might promote cell-level osseointegration of titanium implants, but there was no statistically significant effects.
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Lasers Med Sci.  2012 Jul 24. [Epub ahead of print]

Biomechanical effect of one session of low-level laser on the bone-titanium implant interface.

Boldrini C, de Almeida JM, Fernandes LA, Ribeiro FS, Garcia VG, Theodoro LH, Pontes AE.

Source

Master of Science Course, Educational Foundation of Barretos, UNIFEB, Rua Prof. Roberto Frade Monte 389, Bairro Aeroporto, 14783-226, Barretos, SP, Brazil.

Abstract

Low-level laser (LLL) has been used on peri-implant tissues for accelerating bone formation. However, the effect of one session of LLL in the strength of bone-implant interface during early healing process remains unclear. The present study aims to evaluate the removal torque of titanium implants irradiated with LLL during surgical preparation of implant bed, in comparison to non-irradiation. Sixty-four Wistar rats were used. Half of the animals were included in LLL group, while the other half remained as control. All animals had the tibia prepared with a 2 mm drill, and a titanium implant (2.2?×?4 mm) was inserted. Animals from LLL group were irradiated with laser (gallium aluminum arsenide), with a wavelength of 808 nm, a measured power output of 50 mW, to emit radiation in collimated beams (0.4 cm(2)), for 1 min and 23 s, and an energy density of 11 J/cm(2). Two applications (22 J/cm(2)) were performed immediately after bed preparation for implant installation. Flaps were sutured, and animals from both groups were sacrificed 7, 15, 30, and 45 days after implant installation, when load necessary for removing implant from bone was evaluated by using a torquimeter. In both groups, torque values tended to increase overtime; and at 30 and 45 days periods, values were statistically higher for LLL group in comparison to control (ANOVA test, p?<?0.0001). Thus, it could be suggested that a single session of irradiation with LLL was beneficial to improve bone-implant interface strength, contributing to the osseointegration process.

J Oral Implantol.  2011 May 2. [Epub ahead of print]

Effect of surface roughness and low-level laser therapy(LLLT) on removal torque of implants placed in rat femurs.

Primo BT, Cordeiro da Silva R, Grossmann E, Quevedo Miguens Júnior SA, Gonzalez Hernandez PA, Silva Júnior AN.

Source

Universidade Luterana do Brasil, Oral and Maxillofacial Surgery, Universidade Luterana do Brasil.

Abstract

Abstract The present study measured removal torque and bone-implant interface resistance of machined implants, acid etched implants, or machined implants irradiated around the implant area with infrared low-level laser therapy (LLLT; 830 nm) immediately after surgery. There were statistically significant differences between Groups A (control) and B (rough surface) (p=0.03). Implants with a rough surface seem to add resistance to the bone-implant interface when compared with smooth titanium implants or implants treated with LLLT.

Braz Dent J. 2010;21(6):491-498.

Effects of low-level laser therapy on human osteoblastic cells grown on titanium.

Petri AD, Teixeira LN, Crippa GE, Beloti MM, Oliveira PT, Rosa AL.

Cell Culture Laboratory, Ribeirão Preto Dental School, University of São Paulo, Ribeirão Preto, SP, Brazil.

Abstract

The aim of this study was to investigate the effects of low-level laser therapy (LLLT) by using gallium aluminum arsenide (GaAlAs) diode laser on human osteoblastic cells grown on titanium (Ti). Osteoblastic cells were obtained by enzymatic digestion of human alveolar bone and cultured on Ti discs for up to 17 days. Cells were exposed to LLLT at 3 J/cm2 (wavelength of 780 nm) at days 3 and 7 and non-irradiated cultures were used as control. LLLT treatment did not influence culture growth, ALP activity, and mineralized matrix formation. Analysis of cultures by epifluorescence microscopy revealed an area without cells in LLLT treated cultures, which was repopulated latter with proliferative and less differentiated cells. Gene expression of ALP, OC, BSP, and BMP-7 was higher in LLLT treated cultures, while Runx2, OPN, and OPG were lower. These results indicate that LLLT modulates cell responses in a complex way stimulating osteoblastic differentiation, which suggests possible benefits on implant osseointegration despite a transient deleterious effect immediately after laser irradiation.Este estudo teve como objetivo investigar o efeito do laser diodo de gálio-alumÃ-nio-arsênio (GaAlAs) em células osteoblásticas humanas cultivadas sobre discos de Ti. Para tanto, células osteoblásticas foram obtidas por digestão enzimática de osso alveolar humano e cultivadas sobre discos de Ti por 17 dias. As células foram submetidas à irradiação no 3º e 7º dias na dose de 3 J/cm2 e comprimento de onda de 780 nm e células não irradiadas foram usadas como controle. A irradiação não alterou a proliferação celular, atividade de ALP e formação de matriz mineralizada. Microscopia por epifluorescência indicou que após 24 h da aplicação do laser, as culturas irradiadas apresentaram áreas sem células, que mais tarde foram repovoadas por células em fase de proliferação e menos diferenciadas. O laser aumentou a expressão gênica relativa da ALP, OC, BSP e BMP-7 e reduziu a de RUNX2, OPN e OPG. Os resultados indicam que a terapia com laser modula de forma complexa as respostas celulares, estimulando a diferenciação osteoblástica. Assim, é possÃ-vel sugerir possÃ-veis benefÃ-cios do laser na osseointegração de implantes de Ti apesar do efeito deletério às células imediatamente após a irradiação.

Lasers Med Sci. 2010 Apr 15. [Epub ahead of print]

 

Mechanical evaluation of the influence of low-level laser therapy in secondary stability of implants in mice shinbones.

Maluf AP, Maluf RP, da Rocha Brito C, França FM, de Brito RB Jr.

São Leopoldo Mandic Dental Research Institute, Campinas, SP, Brazil, alemaluf@terra.com.br.

Abstract

The present work evaluates mechanically the bone-implant attachment submitted or not to low-level laser therapy, with wavelength of 795 nm, in a continuous way, with power of 120 mW. The implant was placed in one of the shinbones of 24 mice, randomly distributed into two groups. The experimental group was submitted to six laser applications, divided into four points previously established, two lateral and two longitudinal, six times 8 J/cm(2) with an interval of 2 days, totaling the dose of 48 J/cm(2). The control group did not receive laser therapy. The interval between applications was 48 h and the irradiations began immediately after the end of the implant surgeries. The two groups were killed on the 14th day and a bone block of the area was removed where the implant was inserted. A torque machine was used to measure the torque needed for loosening the implants. A statistically significant difference was observed between the two groups. The experimental group presented larger difficulty for breaking up the implant interface with the bone block than the control group. It can be concluded that with the animal model and the protocol of irradiation present in this study, the laser therapy demonstrated capacity to increase the attachment bone implant.

J Mater Sci Mater Med. 2009 Nov 27. [Epub ahead of print]

Low level laser therapy does not modulate the outcomes of a highly bioactive glass-ceramic (Biosilicate((R))) on bone consolidation in rats.

Oliveira P, Ribeiro DA, Pipi EF, Driusso P, Parizotto NA, Renno AC.

Department of Physiotherapy, Federal University of São Carlos, Rodovia Washington Luís (SP-310), Km 235, São Carlos, SP, Brazil.

The main purpose of the present work was to evaluate if low level laser therapy (LLLT) can improve the effects of novel fully-crystallized glass-ceramic (Biosilicate((R))) on bone consolidation in tibial defects of rats. Forty male Wistar rats with tibial bone defects were used. Animals were divided into four groups: group bone defect control (CG); group bone defect filled with Biosilicate((R)) (BG); group bone defect filled with Biosilicate((R)), irradiated with LLLT, at 60 J cm(-2) (BG 60) and group bone defect filled with Biosilicate((R)), irradiated with LLLT, at 120 J cm(-2) (BG 120). A low-energy GaAlAs 830 nm, CW, 0.6 mm beam diameter, 100 W cm(-2), 60 and 120 J cm(-)(2) was used in this study. Laser irradiation was initiated immediately after the surgery procedure and it was performed every 48 h for 14 days. Fourteen days post-surgery, the three-point bending test revealed that the structural stiffness of the groups CG and BG was higher than the values of the groups BG60 and BG120. Morphometric analysis revealed no differences between the control group and the Biosilcate((R)) group. Interestingly, the groups treated with Biosilicate((R)) and laser (BG 60 and BG120) showed statistically significant lower values of newly formed bone in the area of the defect when compared to negative control (CG) and bone defect group filled with Biosilicate (CB). Our findings suggest that although Biosilicate((R)) exerts some osteogenic activity during bone repair, laser therapy is not able to modulate this process.

Photomed Laser Surg. 2009 Oct 27. [Epub ahead of print]

Low-Level Laser Therapy for Implants Without Initial Stability.

Campanha BP, Gallina C, Geremia T, Loro RC, Valiati R, Hübler R, de Oliveira MG.

1 School of Dentistry, Universidade Federal de Minas Gerais , Belo Horizonte, Brazil .

Abstract Objective: This study evaluated the effect of low-level infrared laser on removal torque values of implants with poor initial stability inserted in rabbit tibias. Background Data: It is important to analyze the effects of laser radiation on bone repair when low-quality bone and implants with poor initial stability are used. Materials and Methods: Thirty male white New Zealand rabbits (Oryctolagus Cuniculus) about 2 mo old and weighing 1.5-2.0 kg were used. Machined implants with poor initial stability were inserted in the tibia of each animal. Animals were randomly divided into two groups: laser irradiated and laser nonirradiated. Each group was further divided into three subgroups, according to the day the animals were killed: 15, 30, or 45 d. Torque values were measured with an axial digital torquemeter that applied counter-torque. The Student’s t-test was used to calculate means and standard deviations for the comparisons between laser and control groups. Results: A significant increase (p = 0.050) in removal torque values was found in the group of laser-irradiated implants at 15 and 30 d when compared with the control groups. At 45 d, no significant differences were found. Conclusion: In this study, low-level laser therapy promoted the osseointegration of implants with poor initial stability, particularly in the initial stages of bone healing.

Int J Oral Maxillofac Implants. 2009 Jan-Feb;24(1):47-51.

The effect of low-intensity laser therapy on bone healing around titanium implants: a histometric study in rabits.

Pereira CL, Sallum EA, Nociti FH Jr, Moreira RW.

Division of Oral and Maxillofacial Surgery, Piracicaba Dental School, Campinas State University, Piracicaba, São Paulo, Brazil.

Abstract

PURPOSE: This study aimed to histometrically evaluate the influence of low-intensity laser treatment on bone healing around titanium implants placed in rabbit tibiae. MATERIALS AND METHODS: Each tibia of 12 adult rabbits received a 3.3 x 6-mm titanium implant. The implants placed in the right tibiae were irradiated with a gallium-aluminum-arsenide diode low-intensity laser every 48 hours for 14 days postoperatively, and the left tibiae were not irradiated. After 3 or 6 weeks, the animals were sacrificed (six animals per period), and nondecalcified sections were obtained and analyzed for bone-to-implant contact (BIC) and bone area within the implant threads. Data were subjected to statistical analysis using analysis of variance (ANOVA) and the Tukey test. RESULTS: BIC was significantly increased in the laser-treated group at both 3 weeks and 6 weeks. BIC did not increase significantly with time (3 weeks versus 6 weeks). Conversely, bone area within the threads was significantly increased with time (3 weeks versus 6 weeks), regardless of whether the laser was used. Considering bone area within the threads, no significant difference was found for treatment, eg, with or without laser. CONCLUSION: Low-intensity laser therapy did not affect the area of bone formed within the threads, but it may improve BIC in rabbit tibiae.

Clin Oral Implants Res. 2006 Dec;17(6):638-43.

Neodymium:yttrium aluminum garnet laser irradiation with low pulse energy: a potential tool for the treatment of peri-implant disease.

Giannini R, Vassalli M, Chellini F, Polidori L, Dei R, Giannelli M.

Department of Anatomy, Histology and Forensic Medicine, University of Florence, Florence, Italy.

Bacterial contamination may seriously compromise successful implant osteointegration in the clinical practice of dental implantology. Several methods for eliminating bacteria from the infected implants have been proposed, but none of them have been shown to be an effective tool in the treatment of peri-implantitis. In the present study, we investigated the efficacy of pulsed neodymium:yttrium aluminum garnet laser irradiation (Nd:YAG) in achieving bacterial ablation while preserving the surface properties of titanium implants. For this purpose, suspensions of Escherichia coli or Actinobacillus (Haemophilus) actinomycetemcomitans were irradiated with different laser parameters, both streaked on titanium implants, and in broth medium. It was found, by light and atomic force microscopy, that Nd:YAG laser, when used with proper working parameters, was able to bring about a consistent microbial ablation of both aerobic and anaerobic species, without damaging the titanium surface.

Swed Dent J Suppl. 2005;(172):1-63.

The effect of low level laser irradiation on implant-tissue interaction. In vivo and in vitro studies.

Khadra M.

Department of Oral Surgery and Oral Medicine, Faculty of Dentistry, University of Oslo, Norway.

Low-level laser therapy (LLLT) is increasingly used in medicine and dentistry. It has been suggested that LLLT may be beneficial in the management of many different medical conditions, including pain, wound healing and nerve injury. The present thesis is based on a series of in vivo and in vitro experimental studies investigating whether LLLT has the potential to enhance titanium-implant interaction. Information about LLLT effect on bone healing is fundamental to understand whether LLLT may improve implant-tissue interaction. Thus in the initial study (I), the effect of LLLT on bone healing and growth in rat calvarial bone defects was investigated. It was found that LLLT may accelerate metabolism and/or mineralization during early bone healing. Based on these findings, study II explored the hypothesis that LLLT can enhance implant integration in the rabbit tibial bone. It was shown that LLLT stimulated the mechanical strength of the interface between the implant and bone after a healing period of 8 weeks. Histomorphometrical and mineral analyses showed that the irradiated implants had greater bone-to-implant contact than the controls. In the in vitro experiments, cellular responses to LLLT were studied in two cell types: primary cultures of human gingival fibroblasts and human osteoblast-like cells, with special reference to attachment, proliferation, differentiation and production of transforming growth factor beta1 (TGF-beta1). The objectives of studies III & IV were to develop a standardized, reproducible in vitro model for testing a GaAlAs diode laser device and to document the influence of single or multiple doses of LLLT, as a guide to defining the optimal laser dose for enhancing cell activity. A further objective was to investigate the effect of LLLT on initial attachment and subsequent behaviour of human gingival fibroblasts cultured on titanium. While both multiple doses (1.5 and 3 J/cm2) and a single dose (3 J/cm2) enhanced cellular attachment, proliferation increased only after multiple doses (1.5 and 3 J/cm2). Study V concerned the response to LLLT of osteoblast-like cells, derived from human alveolar bone cultured on titanium implant material. In this study LLLT significantly enhanced cellular attachment. Greater cell proliferation in the irradiated groups was observed first after 96 h indicating that the cellular response is dose dependent. Osteocalcin synthesis and TGF-beta1 production were significantly stimulated on the samples exposed to 3 J/cm2. The following conclusions are drawn from the results of these five studies: LLLT can promote bone healing and bone mineralization and thus may be clinically beneficial in promoting bone formation in skeletal defects. It may be also used as additional treatment for accelerating implant healing in bone. LLLT can modulate the primary steps in cellular attachment and growth on titanium surfaces. Multiple doses of LLLT can improve LLLT efficacy, accelerate the initial attachment and alter the behaviour of human gingival fibroblasts cultured on titanium surfaces. The use of LLLT at the range of doses between 1.5 and 3 J/cm2 may modulate the activity of cells interacting with an implant, thereby enhancing tissue healing and ultimate implant success..

Clin Oral Implants Res. 2004 Jun;15(3):325-32.

Low-level laser therapy stimulates bone-implant interaction: an experimental study in rabbits.

Khadra M, Rønold HJ, Lyngstadaas SP, Ellingsen JE, Haanaes HR.

Department of Oral Surgery and Oral Medicine, Faculty of Dentistry, University of Oslo, Oslo, Norway. maawan@odont.uio.no

Abstract

The aim of the present study was to investigate the effect of low-level laser therapy (LLLT) with a gallium-aluminium-arsenide (GaAlAs) diode laser device on titanium implant healing and attachment in bone. This study was performed as an animal trial of 8 weeks duration with a blinded, placebo-controlled design. Two coin-shaped titanium implants with a diameter of 6.25 mm and a height of 1.95 mm were implanted into cortical bone in each proximal tibia of twelve New Zealand white female rabbits (n=48). The animals were randomly divided into irradiated and control groups. The LLLT was used immediately after surgery and carried out daily for 10 consecutive days. The animals were killed after 8 weeks of healing. The mechanical strength of the attachment between the bone and 44 titanium implants was evaluated using a tensile pullout test. Histomorphometrical analysis of the four implants left in place from four rabbits was then performed. Energy-dispersive X-ray microanalysis was applied for analyses of calcium and phosphorus on the implant test surface after the tensile test. The mean tensile forces, measured in Newton, of the irradiated implants and controls were 14.35 (SD+/-4.98) and 10.27 (SD+/-4.38), respectively, suggesting a gain in functional attachment at 8 weeks following LLLT (P=0.013). The histomorphometrical evaluation suggested that the irradiated group had more bone-to-implant contact than the controls. The weight percentages of calcium and phosphorus were significantly higher in the irradiated group when compared to the controls (P=0.037) and (P=0.034), respectively, suggesting that bone maturation processed faster in irradiated bone. These findings suggest that LLLT might have a favourable effect on healing and attachment of titanium implants.

Clin Oral Implants Res. 2002 Jun;13(3):288-92.

Effect of low-power laser irradiation on bony implant sites.

Dörtbudak O, Haas R, Mailath-Pokorny G.

Department of Oral Surgery, Dental School, University of Vienna, Austria. orhun.doerbudak@univie.ac.at

Abstract

This study was designed to examine the effects of low-energy laser irradiation on osteocytes and bone resorption at bony implant sites. Five male baboons with a mean age of 6.5 years were used in the study. Four holes for accommodating implants were drilled in each iliac crest. Sites on the left side were irradiated with a 100 mW low-energy laser (690 nm) for 1 min (6 Joule) immediately after drilling and insertion of four sandblasted and etched (Frialit-2 Synchro) implants. Five days later, the bone was removed en bloc and was evaluated histomorphometrically. The mean osteocyte count per unit area was 109.8 cells in the irradiated group vs. 94.8 cells in the control group. As intra-individual cell counts varied substantially, osteocyte viability was used for evaluation. In the irradiated group, viable osteocytes were found in 41.7% of the lacuna vs. 34.4% in the non-irradiated group. This difference was statistically significant at P < 0.027. The total resorption area, eroded surface, was found to be 24.9% in the control group vs. 24.6% in the irradiated group. This difference was not statistically significant. This study showed that osteocyte viability was significantly higher in the samples that were subjected to laser irradiation immediately after implant site drilling and implant insertion, in comparison to control sites. This may have positive effects on the integration of implants. The bone resorption rate, in contrast, was not affected by laser irradiation.

J Clin Laser Med Surg. 2001 Oct;19(5):261-5.

 

Optimal dosing of intravascular low-power red laser light as an adjunct to coronary stent implantation: insights from a porcine coronary stent model.

De Scheerder IK, Wang K, Zhou XR, Szilard M, Verbeken E, Ping QB, Yanming H, Jianhua H, Nikolaychik V, Moses JW, Kipshidze N, Van de Werf F.

University Hospitals, Leuven, Belgium.

BACKGROUND: It is believed that restenosis following coronary interventions is the result of endothelial denudation that leads to thrombus formation, vascular remodeling, and smooth muscle cell proliferation. Low-power red laser light (LPRLL) irradiation enhances endothelial cell growth in vitro and in vivo, and reduces restenosis in animal models. The present study investigated the optimal dose of intravascular LPRLL therapy in the prevention of in-stent stenosis in a porcine coronary stent model. METHODS AND RESULTS: Selected right coronary artery segments were pretreated with a LPRLL balloon, delivering a dose of 0 mW during 1 min (group 1, n = 10), 50 mW during 1 min (group II, n = 10), or 100 mW during 1 min (group III, n = 10) before stenting. Quantitative coronary analysis of the stented vessel was performed before stenting, immediately after stenting, and at 6 weeks follow-up. The pigs were sacrificed, and histologic and morphometric analyses were conducted. At 6 weeks, minimal luminal stent diameter was significantly narrower in the control group compared to the 50-mW dose group (p < 0.05). These results were confirmed by morphometric analysis. Neointimal area was also significantly decreased in the 50-mW dose group. CONCLUSIONS: Intravascular LPRLL contributes to reduction of angiographic in-stent restenosis and neointimal hyperplasia in this animal model. The optimal dose using the LPRLL balloon system seems to be approximately 5 mW delivered during 1 min.

J Invasive Cardiol. 1998 Nov;10(9):534-538.

 

Intravascular Red Light Therapy after Coronary Stenting N Angiographic and Clinical Follow-up Study in Humans.

Kaul U, Singh B, Sudan D, Ghose T, Kipshidze N.

Director, Interventional Cardiology, Batra Hospital and Medical Research Centre 1, Tughlakabad Institutional Area, Mehrauli Badarpur Road, New Delhi-110 062, India.

In animal models of coronary restenosis, intravascular red light therapy (IRLT) using a diode laser source has been shown to reduce neointimal hyperplasia following balloon-induced injury and coronary stenting. We studied the safety and efficacy of catheter-based IRLT for preventing restenosis after coronary stenting in 22 patients with angina pectoris. IRLT was performed using a diode laser (650 nm) at an energy level of 10 megawatts delivered through a rapid exchange balloon system containing the fiberoptics. The procedure was successful in all patients, with no procedural or in-hospital complications. Two patients with recurrence of symptoms had angiography at 3 and 4.1 months respectively. Angiographic follow-up was also done after 6 months in the 20 remaining asymptomatic patients. The mean minimal lumen diameter (MLD) for the whole group at 6 months follow-up was 2.57 +/- 0.62 mm. The calculated late lumen loss was 0.49 +/- 1.12 mm with a late loss index of 0.21 +/- 0.54. Four patients (2 symptomatic and 2 asymptomatic) in the series developed angiographic restenosis. Clinical events at follow-up of 10.9 +/- 3.5 months were repeat angioplasty in 2 patients for symptomatic restenosis with a 91% event free survival. These preliminary results demonstrate that IRLT after coronary artery stenting is safe and feasible; it is associated with low rates of angiographic indices of restenosis

Int J Oral Maxillofac Implants. 2009 Jan-Feb;24(1):47-51.

The effect of low-intensity laser therapy on bone healing around titanium implants: a histometric study in rabbits.

Pereira CL, Sallum EA, Nociti FH Jr, Moreira RW.

Division of Oral and Maxillofacial Surgery, Piracicaba Dental School, Campinas State University, Piracicaba, São Paulo, Brazil.

PURPOSE: This study aimed to histometrically evaluate the influence of low-intensity laser treatment on bone healing around titanium implants placed in rabbit tibiae. MATERIALS AND METHODS: Each tibia of 12 adult rabbits received a 3.3 x 6-mm titanium implant. The implants placed in the right tibiae were irradiated with a gallium-aluminum-arsenide diode low-intensity laser every 48 hours for 14 days postoperatively, and the left tibiae were not irradiated. After 3 or 6 weeks, the animals were sacrificed (six animals per period), and nondecalcified sections were obtained and analyzed for bone-to-implant contact (BIC) and bone area within the implant threads. Data were subjected to statistical analysis using analysis of variance (ANOVA) and the Tukey test. RESULTS: BIC was significantly increased in the laser-treated group at both 3 weeks and 6 weeks. BIC did not increase significantly with time (3 weeks versus 6 weeks). Conversely, bone area within the threads was significantly increased with time (3 weeks versus 6 weeks), regardless of whether the laser was used. Considering bone area within the threads, no significant difference was found for treatment, eg, with or without laser. CONCLUSION: Low-intensity laser therapy did not affect the area of bone formed within the threads, but it may improve BIC in rabbit tibiae.

Biomaterials. 2005 Jun;26(17):3503-9

Effect of laser therapy on attachment, proliferation and differentiation of human osteoblast-like cells cultured on titanium implant material.

Khadra M, Lyngstadaas SP, Haanaes HR, Mustafa K.

Department of Oral Surgery and Oral Medicine, Faculty of Dentistry, University of Oslo, P.O.Box 1109 Blindern, N-0317 Oslo, Norway. maawan@odont.uio.no

The aim of this in vitro study was to investigate the effect of low-level laser therapy (LLLT) on the attachment, proliferation, differentiation and production of transforming growth factor-ss(1) (TGF-beta(1)) by human osteoblast-like cells (HOB). Cells derived from human mandibular bone were exposed to GaAlAs diode laser at dosages of 1.5 or 3 J/cm(2) and then seeded onto titanium discs. Non-irradiated cultures served as controls. After 1, 3 and 24h, cells were stained and the attached cells were counted under a light microscope. In order to investigate the effect of LLLT on cell proliferation after 48, 72 and 96 h, cells were cultured on titanium specimens for 24h and then exposed to laser irradiation for three consecutive days. Specific alkaline phosphatase activity and the ability of the cells to synthesize osteocalcin after 10 days were investigated using p-nitrophenylphosphate as a substrate and the ELSA-OST-NAT immunoradiometric kit, respectively. Cellular production of TGF-beta(1) was measured by an enzyme-linked immunosorbent assay (ELISA), using commercially available kits. LLLT significantly enhanced cellular attachment (P<0.05). Greater cell proliferation in the irradiated groups was observed first after 96 h. Osteocalcin synthesis and TGF-beta(1) production were significantly greater (P<0.05) on the samples exposed to 3 J/cm(2). However, alkaline phosphatase activity did not differ significantly among the three groups. These results showed that in response to LLLT, HOB cultured on titanium implant material had a tendency towards increased cellular attachment, proliferation, differentiation and production of TGF-beta(1), indicating that in vitro LLLT can modulate the activity of cells and tissues surrounding implant material.

Clin Oral Implants Res. 2004 Jun;15(3):325-32.

 

Low-level laser therapy stimulates bone-implant interaction: an experimental study in rabbits.

Khadra M, Ronold HJ, Lyngstadaas SP, Ellingsen JE, Haanaes HR.

Department of Oral Surgery and Oral Medicine, Faculty of Dentistry, University of Oslo, Oslo, Norway. maawan@odont.uio.no

The aim of the present study was to investigate the effect of low-level laser therapy (LLLT) with a gallium-aluminium-arsenide (GaAlAs) diode laser device on titanium implant healing and attachment in bone. This study was performed as an animal trial of 8 weeks duration with a blinded, placebo-controlled design. Two coin-shaped titanium implants with a diameter of 6.25 mm and a height of 1.95 mm were implanted into cortical bone in each proximal tibia of twelve New Zealand white female rabbits (n=48). The animals were randomly divided into irradiated and control groups. The LLLT was used immediately after surgery and carried out daily for 10 consecutive days. The animals were killed after 8 weeks of healing. The mechanical strength of the attachment between the bone and 44 titanium implants was evaluated using a tensile pullout test. Histomorphometrical analysis of the four implants left in place from four rabbits was then performed. Energy-dispersive X-ray microanalysis was applied for analyses of calcium and phosphorus on the implant test surface after the tensile test. The mean tensile forces, measured in Newton, of the irradiated implants and controls were 14.35 (SD+/-4.98) and 10.27 (SD+/-4.38), respectively, suggesting a gain in functional attachment at 8 weeks following LLLT (P=0.013). The histomorphometrical evaluation suggested that the irradiated group had more bone-to-implant contact than the controls. The weight percentages of calcium and phosphorus were significantly higher in the irradiated group when compared to the controls (P=0.037) and (P=0.034), respectively, suggesting that bone maturation processed faster in irradiated bone. These findings suggest that LLLT might have a favourable effect on healing and attachment of titanium implants.

Biomaterials. 2005 Jun;26(17):3503-9.

Effect of laser therapy on attachment, proliferation and differentiation of human osteoblast-like cells cultured on titanium implant material.

Khadra M, Lyngstadaas SP, Haanaes HR, Mustafa K.

Department of Oral Surgery and Oral Medicine, Faculty of Dentistry, University of Oslo, P.O.Box 1109 Blindern, N-0317 Oslo, Norway. maawan@odont.uio.no

The aim of this in vitro study was to investigate the effect of low-level laser therapy (LLLT) on the attachment, proliferation, differentiation and production of transforming growth factor-ss(1) (TGF-beta(1)) by human osteoblast-like cells (HOB). Cells derived from human mandibular bone were exposed to GaAlAs diode laser at dosages of 1.5 or 3 J/cm(2) and then seeded onto titanium discs. Non-irradiated cultures served as controls. After 1, 3 and 24h, cells were stained and the attached cells were counted under a light microscope. In order to investigate the effect of LLLT on cell proliferation after 48, 72 and 96 h, cells were cultured on titanium specimens for 24h and then exposed to laser irradiation for three consecutive days. Specific alkaline phosphatase activity and the ability of the cells to synthesize osteocalcin after 10 days were investigated using p-nitrophenylphosphate as a substrate and the ELSA-OST-NAT immunoradiometric kit, respectively. Cellular production of TGF-beta(1) was measured by an enzyme-linked immunosorbent assay (ELISA), using commercially available kits. LLLT significantly enhanced cellular attachment (P<0.05). Greater cell proliferation in the irradiated groups was observed first after 96 h. Osteocalcin synthesis and TGF-beta(1) production were significantly greater (P<0.05) on the samples exposed to 3 J/cm(2). However, alkaline phosphatase activity did not differ significantly among the three groups. These results showed that in response to LLLT, HOB cultured on titanium implant material had a tendency towards increased cellular attachment, proliferation, differentiation and production of TGF-beta(1), indicating that in vitro LLLT can modulate the activity of cells and tissues surrounding implant material.

Clin Oral Implants Res. 2004 Jun;15(3):325-32.

Low-level laser therapy stimulates bone-implant interaction: an experimental study in rabbits.

Khadra M, Ronold HJ, Lyngstadaas SP, Ellingsen JE, Haanaes HR.

Department of Oral Surgery and Oral Medicine, Faculty of Dentistry, University of Oslo, Oslo, Norway. maawan@odont.uio.no

The aim of the present study was to investigate the effect of low-level laser therapy (LLLT) with a gallium-aluminium-arsenide (GaAlAs) diode laser device on titanium implant healing and attachment in bone. This study was performed as an animal trial of 8 weeks duration with a blinded, placebo-controlled design. Two coin-shaped titanium implants with a diameter of 6.25 mm and a height of 1.95 mm were implanted into cortical bone in each proximal tibia of twelve New Zealand white female rabbits (n=48). The animals were randomly divided into irradiated and control groups. The LLLT was used immediately after surgery and carried out daily for 10 consecutive days. The animals were killed after 8 weeks of healing. The mechanical strength of the attachment between the bone and 44 titanium implants was evaluated using a tensile pullout test. Histomorphometrical analysis of the four implants left in place from four rabbits was then performed. Energy-dispersive X-ray microanalysis was applied for analyses of calcium and phosphorus on the implant test surface after the tensile test. The mean tensile forces, measured in Newton, of the irradiated implants and controls were 14.35 (SD+/-4.98) and 10.27 (SD+/-4.38), respectively, suggesting a gain in functional attachment at 8 weeks following LLLT (P=0.013). The histomorphometrical evaluation suggested that the irradiated group had more bone-to-implant contact than the controls. The weight percentages of calcium and phosphorus were significantly higher in the irradiated group when compared to the controls (P=0.037) and (P=0.034), respectively, suggesting that bone maturation processed faster in irradiated bone. These findings suggest that LLLT might have a favourable effect on healing and attachment of titanium implants.

Clin Oral Implants Res. 2003 Apr;14(2):226-32.

Osseointegration of endosseous ceramic implats after postoperative low-power laser stimulation: an in vivo comparative study.

Guzzardella GA, Torricelli P, Nicoli-Aldini N, Giardino R.

Department of Experimental Surgery/Codivilla-Putti Research Institute, Rizzoli Orthopaedic Institute, Bologna, Italy. gaetanoantonio.guzzardella@ior.it
Stimulation with low-power laser (LPL) can enhance bone repair as reported in experimental studies on bone defects and fracture healing. Little data exist concerning the use of LPL postoperative stimulation to improve osseointegration of endosseous implants in orthopaedic and dental surgery. An in vivo model was used for the present study to evaluate whether Ga-Al-As (780 nm) LPL stimulation can improve biomaterial osseointegration. After drilling holes, cylindrical implants of hydroxyapatite (HA) were placed into both distal femurs of 12 rabbits. From postoperative day 1 and for 5 consecutive days, the left femurs of all rabbits were submitted to LPL treatment (LPL group) with the following parameters: 300 J/cm2, 1 W, 300 Hz, pulsating emission, 10 min. The right femurs were sham-treated (control group). Three and 6 weeks after implantation, histomorphometric and microhardness measurements were taken. A higher affinity index was observed at the HA-bone interface in the LPL group at 3 (P<0.0005) and 6 weeks (P<0.001); a significant difference in bone microhardness was seen in the LPL group vs. the control group (P<0.01). These results suggest that LPL postoperative treatment enhances the bone-implant interface.

Clin Oral Implants Res. 2002 Jun;13(3):288-92.

Effect of low-power laser irradiation on bony implant sites.

Dortbudak O, Haas R, Mailath-Pokorny G.

Department of Oral Surgery, Dental School, University of Vienna, Austria. orhun.doerbudak@univie.ac.at

This study was designed to examine the effects of low-energy laser irradiation on osteocytes and bone resorption at bony implant sites. Five male baboons with a mean age of 6.5 years were used in the study. Four holes for accommodating implants were drilled in each iliac crest. Sites on the left side were irradiated with a 100 mW low-energy laser (690 nm) for 1 min (6 Joule) immediately after drilling and insertion of four sandblasted and etched (Frialit-2 Synchro) implants. Five days later, the bone was removed en bloc and was evaluated histomorphometrically. The mean osteocyte count per unit area was 109.8 cells in the irradiated group vs. 94.8 cells in the control group. As intra-individual cell counts varied substantially, osteocyte viability was used for evaluation. In the irradiated group, viable osteocytes were found in 41.7% of the lacuna vs. 34.4% in the non-irradiated group. This difference was statistically significant at P < 0.027. The total resorption area, eroded surface, was found to be 24.9% in the control group vs. 24.6% in the irradiated group. This difference was not statistically significant. This study showed that osteocyte viability was significantly higher in the samples that were subjected to laser irradiation immediately after implant site drilling and implant insertion, in comparison to control sites. This may have positive effects on the integration of implants. The bone resorption rate, in contrast, was not affected by laser irradiation.