Bone-Implant Interaction

Lasers Med Sci.  2012 Jul 26. [Epub ahead of print]

The efficacy of the use of IR laser phototherapy associated to biphasic ceramic graft and guided bone regeneration on surgical fractures treated with wire osteosynthesis: a comparative laser fluorescence and Raman spectral study on rabbits.

Pinheiro AL, Santos NR, Oliveira PC, Aciole GT, Ramos TA, Gonzalez TA, da Silva LN, Barbosa AF, Silveira L Jr.

Source

Center of Biophotonics, School of Dentistry, Federal University of Bahia, Av. Araújo Pinho, 62, Canela, Salvador, BA, 40110-150, Brazil, albp@ufba.br

Abstract

The aim of the present study was to assess, by Raman spectroscopy and laser fluorescence, the repair of surgical fractures fixed with wire osteosynthesis treated or not with infrared laser (780 nm, 50 mW, 4×4 J/cm(2)=16 J/cm(2), =0.5 cm(2), CW) associated or not to the use of hydroxyapatite and guided bone regeneration. Surgical tibial fractures were created under general anesthesia on 15 rabbits that were divided into five groups, maintained on individual cages, at day/night cycle, fed with solid laboratory pelted diet, and had water ad libitum. The fractures in groups II, III, IV, and V were fixed with wires. Animals in groups III and V were grafted with hydroxyapatite (HA) and guided bone regeneration (GBR) technique used. Animals in groups IV and V were irradiated at every other day during 2 weeks (4×4 J/cm(2), 16 J/cm(2)=112 J/cm(2)). Observation time was that of 30 days. After animal death, specimens were taken and kept in liquid nitrogen and used for Raman spectroscopy. The Raman results showed basal readings of 1,234.38±220. Groups WO+B+L showed higher readings (1,680.22±822) and group WO+B the lowest (501.425±328). Fluorescence data showed basal readings of 5.83333±0.7. Groups WO showed higher readings (6.91667±0.9) and group WO+B+L the lowest (1.66667±0.5). There were significant differences between groups on both cases (p<0.05). Pearson correlation was negative and significant (R ( 2 ) =-0.60; p <0.001), and it was indicative that, when the Raman peaks of calcium hydroxyapatite (CHA) are increased, the level of fluorescence is reduced. It is concluded that the use of near-infrared lasertherapy associated to HA graft and GBR was effective in improving bone healing on fractured bones as a result of the increasing deposition of CHA measured by Raman spectroscopy and decrease of the organic components as shown by the fluorescence readings.

Lasers Med Sci.  2012 Apr 24. [Epub ahead of print]

The efficacy of the use of IR laser phototherapy associated to biphasic ceramic graft and guided bone regeneration on surgical fractures treated with miniplates: a Raman spectral study on rabbits.

Pinheiro AL, Santos NR, Oliveira PC, Aciole GT, Ramos TA, Gonzalez TA, da Silva LN, Barbosa AF, Junior LS.

Source

Center of Biophotonics, School of Dentistry, Federal University of Bahia, Av. Araújo Pinho, 62, Canela, Salvador, Bahia, CEP:40110-150, Brazil, albp@ufba.br.

Abstract

The aim of the present study was to assess, by Raman spectroscopy, the repair of surgical fractures fixed with internal rigid fixation (IRF) treated or not with IR laser (?780 nm, 50 mW, 4×4 J/cm(2)=16 J/cm(2), =0.5 cm(2), CW) associated or not to the use of hydroxyapatite and guided bone regeneration (GBR). Surgical tibial fractures were created under general anesthesia on 15 rabbits that were divided into five groups, maintained on individual cages, at day/night cycle, fed with solid laboratory pelted diet and had water ad libitum. The fractures in groups II, III, IV and V were fixed with miniplates. Animals in groups III and V were grafted with hydroxyapatite and GBR technique used. Animals in groups IV and V were irradiated at every other day during 2 weeks (4×4 J/cm(2), 16 J/cm(2)=112 J/cm(2)). Observation time was that of 30 days. After animal death, specimens were taken and kept in liquid nitrogen and used for Raman spectroscopy. Raman spectroscopy showed significant differences between groups (p<0.001). Basal readings showed mean value of 1,234±220.1. Group internal rigid fixation + biomaterial + laser showed higher readings (3,521±2,670) and group internal rigid fixation + biomaterial the lowest (212.2±119.8). In conclusion, the results of the present investigation are important clinically as spectral analysis of bone component evidenced increased levels of CHA on fractured sites by using the association of laser light to a ceramic graft.

Photomed Laser Surg. 2010 Oct;28 Suppl 2:S89-97. Epub 2010 Oct 7.

Raman spectroscopy validation of DIAGNOdent-assisted fluorescence readings on tibial fractures treated with laser phototherapy, BMPs, guided bone regeneration, and miniplates.

Pinheiro AL, Lopes CB, Pacheco MT, Brugnera A Jr, Zanin FA, Cangussú MC, Silveira L Jr.

Center of Biophotonics, School of Dentistry, Federal University of Bahia, Salvador, BA, Brazil. albp@ufba.br

Abstract

OBJECTIVES: We aimed to assess through Raman spectroscopy and fluorescence the levels of calcium hydroxyapatite (CHA) and lipids and proteins in complete fractures treated with internal rigid fixation (IRF) treated or not with laser phototherapy (LPT) and associated or not with bone morphogenetic proteins (BMPs) and guided bone regeneration (GBR).

BACKGROUND: Fractures have different etiologies and treatments and may be associated with bone losses. LPT has been shown to improve bone healing.

METHODS: Tibial fractures were created on 15 animals and divided into five groups. LPT started immediately after surgery, repeated at 48-h intervals. Animal death occurred after 30 days.

RESULTS: Raman spectroscopy and fluorescence were performed at the surface. Fluorescence data of group IRF + LPT + Biomaterial showed similar readings to those of the group IRF-no bone loss. Significant differences were seen between groups IRF + LPT + Biomaterial and IRF + LPT; IRF + LPT + Biomaterial; and IRF + Biomaterial; and between IRF + LPT + Biomaterial and IRF. CH groups of lipids and proteins readings showed decreased levels of organic components in subjects treated with the association of LPT, biomaterial, and GBR. Pearson correlation showed that fluorescence readings of both CHA and CH groups of lipids and proteins correlated negatively with the Raman data.

CONCLUSIONS: The use of both methods indicates that the use of the biomaterials associated with infrared LPT resulted in a more-advanced and higher quality of bone repair in fractures treated with miniplates and that the DIAGNOdent may be used to perform optical biopsy on bone.

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 Sep;25(5):693-8.

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

Maluf AP, Maluf RP, Brito Cda R, 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/cm2 with an interval of 2 days, totaling the dose of 48 J/cm2. 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.

Photomed Laser Surg. 2010 Jun;28(3):365-9.

Low-level laser therapy for implants without initial stability.

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

MG.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.

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.

Lasers Med Sci. 2009 Jul;24(4):527-33. Epub 2008 Jul 15.

Effect of soft laser and bioactive glass on bone regeneration in the treatment of bone defects (an experimental study).

AboElsaad NS, Soory M, Gadalla LM, Ragab LI, Dunne S, Zalata KR, Louca C.

Department of Oral Medicine and Periodontology, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.

Abstract

This study aimed to investigate the influence of low-power gallium-aluminium-arsenide (GaAlAs) laser [830 nm, continuous wave (CW), 40 mW and fluence 4 J/cm(2)] on the healing of surgically created bone defects in rats treated with bioactive glass graft material. Surgical bone defects were created in the mandibles of 36 Wistar rats divided into two groups, each consisting of 18 rats. Group I was treated with bioactive glass plus laser irradiation. Group II was treated with graft material only. The animals were killed at 4 weeks, 8 weeks and 12 weeks postoperatively for histological examination. Laser irradiation had significantly accelerated bone healing at 4 weeks and 8 weeks in comparison with that at the sites not irradiated. However at 12 weeks, complete healing of the defects had occurred with no difference detected. Our results have confirmed the positive effect of soft laser in accelerating bone regeneration.

Lasers Med Sci. 2009 May;24(3):387-95. Epub 2008 Jun 26.

Effect of soft laser and bioactive glass on bone regeneration in the treatment of infra-bony defects (a clinical study).

AboElsaad NS, Soory M, Gadalla LM, Ragab LI, Dunne S, Zalata KR, Louca C.

Department of Oral Medicine and Periodontology, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.

Abstract

This study aimed to investigate the influence of low-power 830 nm gallium-aluminium-arsenide (GaAlAs) laser [continuous wave (CW) 40 mW and fluence 4 J/cm(2), with total energy density of 16 J/cm(2)] on the healing of human infra-bony defects treated with bioactive glass graft material. Twenty patients with chronic periodontitis and bilateral infra-bony defects were included. Using a split mouth design, we treated 20 defects with bioactive glass plus laser irradiation during surgical procedures and on days 3, 5, 7 postoperatively; 20 contra-lateral defects were treated with bioactive glass only. Clinical probing pocket depths, clinical attachment levels and standardized periapical radiographs were recorded at baseline and at 3 months and 6 months postoperatively. At 3 months there was a statistically significant difference between the laser and non-laser sites in the parameters investigated. However, at 6 months, no difference was observed. Our results have confirmed the positive effect of soft laser in accelerating periodontal wound healing.

Lasers Med Sci. 2009 May;24(3):447-51. Epub 2008 Jun 20.

Influence of low-level laser therapy on biomaterial osseointegration: a mini-review.

Obradovi? RR, Kesi? LG, Pesevska S.

Department of Oral Medicine and Periodontology, Dental Clinic, Faculty of Medicine, University of Nis, Bul. Nikole Tesle 45/19, 18000, Nis, Serbia. dr.rada@yahoo.com

Abstract

The aim of this paper is to provide an overview of the available literature on low-level laser therapy (LLLT) and its influence on bone repair and the osseointegration of biomaterials. Extensive studies of alveolar bone repair, a common problem in periodontal therapy, have been conduced worldwide. The utility of LLLT in biomaterial osseointegration is still unanswered, due to lack of literature and poorly understood mechanisms. It is still difficult for one to compare studies about the action of LLLT on the osseointegration of biomaterials because the experimental models and duration of treatments are very distinct. However, it could be concluded that LLLT may offer advantages in terms of periodontal and bone functional recovery and biomaterial osseointegration.

J Oral Implantol. 2009;35(1):5-11.

The use of laser technology (Er;Cr:YSGG) and stereolithography to aid in the placement of a subperiosteal implant: case study.

Kusek ER.

University of South Dakota, USA. implantdental@midconetwork.com

Abstract

The use of laser technology has helped this clinician to provide treatment with less postoperative pain and increased healing. The subperiosteal implant is a modality that has been used for several decades, although its popularity has declined in favor of endosseous dental implants. In some instances, however, it remains the treatment of choice, specifically in the atrophic mandible (where placement of endosseous implants is not possible) or when placement would increase the chances of jaw fracture. This article reports the case of a patient rehabilitated using a simplified surgical protocol involving laser surgery and stereolithography.

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 on 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.

Clin Oral Implants Res. 2007 Aug;18(4):517-24. Epub 2007 Apr 19.

Influence of low-level laser treatment on bone regeneration and osseointegration of dental implants following sinus augmentation. An experimental study on sheep.

Jakse N, Payer M, Tangl S, Berghold A, Kirmeier R, Lorenzoni M.

Department of Oral Surgery and Radiology, School of Dentistry, Medical University Graz, Graz, Austria.

Abstract

OBJECTIVES: The aim of this experimental study was to evaluate if low-level laser treatment (LLLT) enhances bone regeneration and osseointegration of dental implants in a sinus graft model.

MATERIAL AND METHODS: Twelve sheep underwent a bilateral sinus floor elevation procedure with cancellous bone from the iliac crest. Implant insertion followed 4 weeks (six sheep) and 12 weeks (six sheep) later. Sixteen weeks after second-stage surgery, animals were sacrificed. Unilaterally, the grafted sinus and during the second-stage surgery the implant sites were irradiated intraoperatively and three times during the first postoperative week with a diode laser (75 mW, 680 nm). The overall energy density per irradiation was 3-4 J/cm(2). Biopsies of the augmented area were obtained during implant insertion and after scarification.

RESULTS: Bone regeneration within the grafted sinus histomorphometric analysis hardly differed between control and test side both 4 and 12 weeks after sinus grafting. Osseointegration measurements resulted in a significantly higher bone/implant contact (BIC) on the test side (P=0.045). Further evaluation of peri-implant bone tends to amount in significant higher percentage on the laser side (P=0.053).

CONCLUSION: The presented experimental study on sheep did not confirm a positive LLLT effect on bone regeneration within a cancellous sinus graft. Nevertheless, LLLT possibly has a positive effect on osseointegration of dental implants inserted after sinus augmentation.

Lasers Surg Med. 2007 Jun;39(5):441-50.

Effect of low-level laser treatment after installation of dental titanium implant-immunohistochemical study of RANKL, RANK, OPG: an experimental study in rats.

Kim YD, Kim SS, Hwang DS, Kim SG, Kwon YH, Shin SH, Kim UK, Kim JR, Chung IK.

Department of Oral and Maxillofacial Surgery, School of Dentistry, Pusan National University, Busan, Korea.

Abstract

BACKGROUND AND OBJECTIVES: This experiment using an animal experimental model was conducted in order to investigate the effect of low-level laser therapy (LLLT) on the healing of the dental titanium implant.

STUDY DESIGN/MATERIALS AND METHODS: The experimental group received LLLT for a week and the control group did not. Each group consisted of 10 rats. Two rats from the groups were euthenized on the days 1, 3, 7, 14, and 21 of the experiment. The expression of receptor activator of nuclear factor kB ligand (RANKL), osteoprotegerin (OPG), and receptor activator of nuclear factor kB (RANK) were investigated.

RESULTS: The expression of RANKL was observed from the initial stage of the installation of the implant for both the experimental and control groups. However, the degree of expression was higher in the experimental group. The degree of expression of OPG increased remarkably in the experimental group, while in the control group the degree of expression increased only slightly. In the experimental group, the expression of RANK was observed from the first day, but in the control group, it was weakly observed after day 3. The overall expression within the bone was slight on day 7 in the control group, while an active expression was observed in the experimental group. Bone density after installation of dental titanium implant during osseointegration in the experimental group was higher than the control group. The surface and structure of the titanium implant was not damaged by low-level laser (LLL).

CONCLUSIONS: From the above results, the expression of OPG, RANKL, and RANK during the osseointegration of the dental titanium implant was observed within bone tissue. The application of the LLL influenced the expression of OPG, RANKL, and RANK, and resulted in the expansion of metabolic bone activity and increased the activity of bone tissue cells.

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.

J Biomed Mater Res A. 2005 Apr 1;73(1):55-62.

Determining optimal dose of laser therapy for attachment and proliferation of human oral fibroblasts 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

Abstract

The purpose of this study was to investigate the influence of single or multiple doses of low-level laser therapy (LLLT) on attachment and proliferation of human gingival fibroblasts in a standardized, reproducible in vitro model. Titanium discs were randomly allotted to one of three groups: group I served as a control, group II was exposed to a single laser dose of 3 J/cm2, and the three subgroups in group III were exposed to laser doses of 0.75, 1.5, and 3 J/cm2. To examine the possible thermal effects of laser exposure on the cell culture, the temperature in the Petri dish was measured for every dose used, before and during irradiation. For attachment assays, groups II and III were exposed to laser irradiation and then seeded onto titanium discs. In group III, the exposures were repeated after 3 and 6 h. Cells were cultured for 6 and 24 h and stained with Hoechst and Propidium. Attached cells were counted under a light microscope. To investigate the effect of LLLT on cell proliferation after 48 h, 72 h, and 7 days, cells were cultured on titanium discs for 24 h and then exposed to laser irradiation for 1 day and 3 consecutive days, respectively. Cell proliferation was determined by counting cells under the microscope and by a cell proliferation enzyme-linked immunosorbent assay system. No increase of temperature of the cell cultures occurred before or during laser exposure at any of the doses tested. Both single and multiple doses of LLLT significantly enhanced cellular attachment (p<0.05). The proliferation assays showed higher cell proliferation (p<0.05) in group III at doses of 1.5 and 3 J/cm2 after 72 h and 7 days, with agreement between staining and enzyme-linked immunosorbent assay. It is concluded that, in this cellular model, the attachment and proliferation of human gingival fibroblasts are enhanced by LLLT in a dose-dependent manner.

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.

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.

Abstract

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.

Photomed Laser Surg. 2005 Feb;23(1):27-31.

Infrared laser light reduces loading time of dental implants: a Raman spectroscopic study.

Lopes CB, Pinheiro AL, Sathaiah S, Duarte J, Cristinamartins M.

IP&D and Department of Dentistry, FCS, UNIVAP, S. J. Campos, São Paulo, Brazil.

Abstract

OBJECTIVE: The aim of this study was to assess, through near-infrared Raman spectroscopy (NIRS), the incorporation of hydroxyapatite of calcium (CHA; approximately 960 cm(1))–on the healing bone around dental implants submitted or not to low-level laser therapy (LLLT) (lambda830 nm).

BACKGROUND DATA: The process of maturation of the bone is important for the success of dental implants, as it improves the fixation of the implant to the bone, allowing the wearing of a prosthesis. LLLT has been suggested as a mean of improving bone healing because of its biomodulatory capabilities.

METHODS: Fourteen rabbits received a titanium implant on the tibia; eight of them were irradiated with lambda830-nm laser (seven sessions at 48-h intervals, 21.5 J/cm(2) per session, 10 mW, phi approximately 0.0028 cm(2), 85 J/cm(2) treatment dose), and six acted as control. The animals were sacrificed at 15, 30, and 45 days after surgery. Specimens were routinely prepared for Raman spectroscopy. Twelve readings were taken on the bone around the implant.

RESULTS: The results showed significant differences in the concentration of CHA on irradiated and control specimens at both 30 and 45 days after surgery (p < 0.001). Conclusion: It is concluded that LLLT does improve bone healing, and this can be safely assessed by Raman spectroscopy.

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

 

Low-level laser therapy stimulates bone-implan interaction: an experimental study on 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 implants with 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.

Effects of low-power laser irradiation on bone 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.

Int J Artif Organs. 2001 Dec;24(12):898-902.

Laser technology in orthopedics: preliminary study on low power laser therapy to improve the bone-biomaterial interface.

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

Experimental Surgery Department, Research Institute Codivilla Putti, Bologna, Italy. gaetanoantonio.guzzardella@ior.it

Abstract

Low Power Laser (LPL) seems to enhance the healing of bone defects and fractures. The effect of LPL in other orthopedic areas such as osteointegration of implanted prosthetic bone devices is still unclear. In the present study, 12 rabbits were used to evaluate whether Ga-Al-As (780 nm) LPL stimulation has positive effects on osteointegration. Hydroxyapatite (HA) cylindrical nails were drilled into both distal femurs of rabbits. From postoperative day 1 and for 5 consecutive days, the left femura of all rabbits were given LPL treatment (Laser Group-LG) with the following parameters: 300 Joule/cm2, 1 Watt, 300 Hertz, pulsating emission, 10 minutes. The right femura were sham-treated (Control Group-CG). At 4 and 8 weeks after implantation, histologic and histomorphometric investigations evaluated bone-biomaterial-contact. Histomorphometry showed a higher degree of osteointegration at the HA-bone interface in the LG Group at 4 (p < 0.0005) and 8 weeks (p < 0.001). These preliminary positive results seem to support the hypothesis that LPL treatment can be considered a good tool to enhance the bone-implant interface in orthopedic surgery.

Int J Oral Maxillofac Implants. 2001 Sep-Oct;16(5):659-67.

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

Deppe H, Horch HH, Henke J, Donath K.

Department of Oral and Maxillofacial Surgery, University of Technology, Munich, Germany. hd@mkg.med.tu-muenchen.de

Abstract

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.