Effects on Bone Tissue After Osteotomy with Different High-Energy Lasers: An Ex Vivo Study.

OBJECTIVE: The purpose of this study was to evaluate the application of Er:YAG and Er,Cr:YSGG lasers during osteotomy in bovine bone blocks. BACKGROUND DATA: Er:YAG/Er,Cr:YSGG lasers for osteotomy procedures have been used to induce tissue ablation without thermal damage. However, even these lasers can induce thermal damages, which can cause a delay on the bone healing. MATERIALS AND METHODS: Sixty standardized bovine bone mandible samples were divided into three groups with 20 samples each: Group 1, Bur; Group 2, Er:YAG laser; and Group 3, Er,Cr:YSGG laser. Two irradiations/cuts were made in each sample. The first was performed until the sample was completely separated into two fragments, and the time required for this procedure was recorded in seconds. The second irradiation/cut was made the same way as the first one; however, it was made partially, without separating the sample into two fragments, but rather making sulci ∼1.5-2 mm deep. Ten samples in each group were used to evaluate the surface morphology of the osteotomy by scanning electron microscopy (SEM), while the other 10 samples were submitted to descriptive histological analysis. RESULTS: The bur was the instrument that performed the osteotomy in the shortest amount of time (p < 0.05). All the instruments caused thermal damage; however, the Er,Cr:YSGG laser was the only type that induced carbonization. CONCLUSIONS: The Er:YAG laser induced the lowest degree of thermal damage in bone tissue after osteotomy; however, a shorter clinical time was required to perform the osteotomy in the bur group.

Effect of Er,Cr:YSGG laser application in the treatment of experimental periodontitis.

The purpose of this study was to evaluate the influence of an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser in the absence or presence of manual scaling and root planning (SRP) for the treatment of induced periodontitis in rats. Ligatures were placed in the subgingival region of the maxillary first molar. After a 7-day period, the ligatures were removed, and 40 rats were randomly divided into four groups (G), as follows: (GI) no treatment, (GII) scaling and root planning (SRP) with curettes, (GIII) Er,Cr:YSGG laser irradiation and (GIV) SRP with curettes followed by Er,Cr:YSGG laser irradiation. Seven and 30 days after the treatment, the animals were sacrificed and histologic, histometric and immunohistochemistry analyses were performed. All groups showed similar histopathological characteristics during the evaluation period. The histometric analysis was confirmed using Bonferroni and paired t tests. At 7 and 30 days, groups II, III and IV exhibited greater bone formation in the furcation area when compared to group I (p < 0.0001; p < 0.05). During the 7-day period, the groups irradiated with the laser (III and IV) showed a statistically larger new bone area than the group treated with SRP (II) (p < 0.01). Immunohistochemistry analysis revealed that the control group exhibited a higher expression of tartrate-resistant acid phosphatase (TRAP) and the receptor activator of nuclear factor κΒ ligand (RANKL) when compared to groups II, III and IV (p < 0.05). All treatments were able to reduce the inflammatory processes, consequently enabling the repair of periodontal tissues. The results achieved with the application of the Er,Cr:YSGG laser suggest that this laser can stimulate greater bone formation, especially over a shorter period of time.

Effects of the Er,Cr:YSGG laser on bone and soft tissue in a rat model.

The purpose of this study was to investigate the histological changes that occur in rat soft and hard tissues after Er,Cr:YSGG laser surgery. Each of 20 rats was submitted to four procedures which were randomly distributed to the right and left sides of the animal: procedure 1 dorsal incision with a scalpel; procedure 2 dorsal incision with a 2.0-W Er,Cr:YSGG laser; procedure 3 skull defect created with a diamond bur; procedure 4 skull defect created with a 3.0-W Er,Cr:YSGG laser. The animals were killed 3, 7, 15 and 30 days after surgery, and histological examinations were performed. The histometric analysis of the bone defects was evaluated using an unpaired t-test. Initially, the dorsum showed more histological signs of repair following procedure 1, although similar healing responses following procedures 1 and 2 were seen on day 30 after surgery. By day 30 the bone formation observed following procedure 4 was much more evident than following procedure 3. The unpaired t-test identified significant differences in bone formation on day 30 (p = 0.01), whereas a greater bone percentage was seen following procedure 4 than following procedure 3 (79.96 ± 10.30% and 58.23 ± 9.99%, respectively). Thus, histological repair of the Er,Cr:YSGG laser wounds was similar to that of the scalpel wounds. However, skull defects created with the Er,Cr:YSGG laser showed greater bone formation than defects created with the bur. Within the limitations of this study, we can conclude that the Er,Cr:YSGG laser is a promising surgical instrument in vivo, particularly for bone surgery.

Avaliação da reparação de feridas cutâneas e ósseas realizadas por técnicas convencionais e com laser de Er, Cr:YSGG: estudo em ratos / Histological evaluation of incisions produced by Er, Cr: YSGG laser in rat soft and hard tissues

O laser cirúrgico de Er,Cr:YSGG (érbio, impregnado por cromo: ítrio, scandio, gálio, garnet) tem sido utilizado no tratamento cirúrgico periodontal, embora poucos estudos histológicos sejam encontrados na literatura. O objetivo deste estudo foi comparar histologicamente a utilização do laser de Er-Cr: YSGG em tecido mole e ósseo em relação à técnicas cirúrgicas convencionais. Foram utilizados 20 ratos, divididos aleatoriamente em 3, 7, 15 e 30 dias, com 5 animais por período. Em cada animal foram realizados os procedimentos (P) nas regiões de dorso e calota, respectivamente: PI) Incisão no dorso com bisturi de lâmina no 15; PII) Incisão no dorso com Laser Er,Cr:YSGG (150mJ de energia, 2.0W de potência), PIII) Defeito ósseo na calota com fresa diamantada esférica em baixa rotação sob refrigeração; PIV) Defeito ósseo na calota com Laser Er,Cr:YSGG (150mJ de energia, 3.0W de potência). Os procedimentos foram randomicamente distribuídos entre lado direito e esquerdo de cada animal. A análise histológica foi avaliada de acordo com a intensidade da resposta inflamatória, presença de áreas necróticas e processo de regeneração tecidual. A análise histométrica dos defeitos ósseos foi confirmada pelo teste estatístico paramétrico ANOVA e complementado pelo teste Bonferroni. Para os procedimentos na região de dorso pode-se observar que nos períodos iniciais houve melhor resposta histológica para o PI, embora no período de 30 dias os procedimentos I e II apresentavam resultados semelhantes. A análise histométrica confirmou uma maior formação óssea na calota com o uso do laser de Er,Cr:YSGG aos 30 dias (79.96±10.30%) em relação ao procedimento com fresa aos 15 (62.05±4.84%) e 30 dias (58.23±9.99%). Na análise histológica em tecido duro, observou-se necrose óssea superficial no PIV em todos os períodos, mas aos 30 dias a formação óssea foi mais evidente no PIV comparado ao PIII. Pode-se concluir que a utilização do laser de Er,Cr:YSGG em tecido mole acarreta atraso na cicatrização, mas que após 30 dias não há diferença entre PI e PII. Aos 30 dias a formação óssea foi estatisticamente maior no PIV quando comparado ao PIII

The Er,Cr:YSGG (Erbium, Chromium:Yttrium­Scandium­Gallium­Garnet) surgical laser has been demonstrated as an useful instrument on dentistry since its wavelength (2,78m) is strongly absorbed by water and hydroxyapatite. The aim of this study was to histologically compare the in vivo healing process that occurs in soft and hard tissues incisions made by Er,Cr:YSGG laser or conventional periodontal surgeries techniques. Twenty rats were used and divided into 4 groups of 5 different periods. On each animal was performed the following procedures (P) in the soft and hard tissue: PI) dorsum incision with scalpel number 15; PII) dorsum irradiation with 2.0W Er,Cr:YSGG laser; PIII) skull defect made by a diamond spherical bur with water refrigeration; PIV) skull defect created by 3.0W Er,Cr:YSGG laser. The procedures were randomly distributed into right and left side of each animal. After sacrifice 3, 7, 15 and 30 days post-surgery the histological examinations were performed. Histometric analysis of the bone defects was confirmed by the parametric statistic test ANOVA and complemented by the Bonferroni test. In the first periods, the histological findings in the dorsum were better in the PI group, although by day 30 PI and PII showed similar healing response. The procedures in the skull revealed superficial necrosis in all periods in the PIV group, although this group had much more evidence of bone formation at day 30 than PIII. The histometric analysis also confirmed a better tissue response for laser application in the skull than conventional techniques, with 79.96±10.30% bone formation by day 30 with Er,Cr:YSGG laser and 62.05±4.84% by day 15 and 58.23±9.99% by day 30 with bur. The utilization of Er,Cr:YSGG laser in soft tissue caused a minimal delay in the healing initial periods but the subsequent tissue remodeling was favorable. Its use on hard tissue revealed statistically greater bone formation than conventional surgeries techniques. Thus, the Er,Cr:YSGG laser is a promising surgical instrument with minimal thermal damage to adjacent tissues in vivo

Aplicação do laser ER, CR: YSGG em periodontia e implantodontia: revisão de literatura / Er, Cr:YSGG laser in periodontics and implant dentistry: review of literature

Os lasers são ferramentas amplamente utilizadas em diversas modalidades terapêuticas em áreas médicas podendo ser divididos em lasers de baixa e alta intensidade. Para o tratamento da doença periodontal, os lasers de baixa intensidade estão relacionados com redução no número de bactérias, propriedades analgésicas e antiinflamatórias e os de alta intensidade podem ser aplicados em procedimentos cirúrgicos, melhorando a hemostasia, promovendo cortes mais precisos, remoção de cálculos dentários, além de interações termomecânicase fotoquímicas com os tecidos. O laser de alta intensidade Érbio impregnado por Cromo: YSGG tem demonstrado resultados satisfatórios quando aplicado em tratamentos endodônticos, restauradores, cirúrgicos e como terapia coadjuvante ao tratamento básico periodontal. O objetivo dessa revisão de literatura foi avaliar os estudos que pesquisaram sobre os efeitos do laser de Er,Cr :YSGG sobre a morfologia e biocompatibilidade de superfícies radiculares e de titânio irradiadas com esse lasers, além do efeito do mesmo no tratamento da doença periodontal e periimplantar.

Lasers are widely used tools in many therapeutic modalities in medical lasers and can be divided into low and high intensity. For the treatment of periodontal disease, lowintensity lasers are related to reduce the number of bacteria and to induce inflammatory and analgesic properties. The high intensity lasers can be used in surgical procedures, improving hemostasis, promoting more accurate cuts, removal of dental calculus as well as thermomechanical and photochemical interactions with tissue. The high-intensity laser Erbium impregnated with chromium: YSGG laser has shown satisfactory results when applied in endodontic, restorative denstistry, surgical procedures and non-surgical periodontal treatment. The purpose of this review is to evaluate the studies that investigated the effects of Er, Cr: YSGG laser on the morphology and biocompatibility of titanium and rootsurfaces irradiated with these lasers, even beyond the effect on the treatment of periodontitis and periimplantitis.