Effects of an Er,Cr:YSGG Laser on Bone Regeneration in Critical-Sized Calvarial Defects of Rats Exposed to Inhalation of Cigarette Smoke.

Objective: To evaluate the effect of the Er,Cr:YSGG laser on healing of critical-sized calvarial defects (CSDs) in rats submitted to inhalation of cigarette smoke. Background: Smoking has been implicated with the delay in the bone healing after osteotomy procedures, then the use of the Er,Cr:YSGG laser for osteotomy in smokers could be an alternative to the conventional drills. Methods: One hundred animals were randomly allocated into four groups: trephine-the CSDs were made with a trephine drill in healthy rats; Er,Cr:YSGG-the CSDs were made with the Er,Cr:YSGG laser in healthy rats; Trephine-S-the CSDs were made with a trephine drill in rats exposed to cigarette smoke; and Er,Cr:YSGG-S-the CSDs were made with the Er,Cr:YSGG laser in rats exposed to cigarette smoke. The inhalation of cigarette smoke started 7 days before the surgical procedure until euthanasia (immediately, 7, 15, 30, or 60 days after the surgical procedure). A histometric analysis and a histological description were performed to evaluate (1) the residual linear lengths and bone formation in the CSDs; (2) the quality of bone healing. Results: The use of Er,Cr:YSGG laser induces more bone formation compared with the trephine in smokers; however, the closure of the CSD was only superior in the Er,Cr:YSGG-S group compared to the Trephine-S group at the 60-day period. Conclusions: The use of the Er,Cr:YSGG laser stimulated the bone repair process after osteotomy procedures in animals submitted to exposure of inhalation of cigarette smoke.

Treatment of periodontal disease with an Er,Cr:YSGG laser in rats exposed to cigarette smoke inhalation.

The purpose of this study was to evaluate the erbium, chromium:yttrium-scandiumgallium-garnet (Er,Cr:YSGG) laser irradiation in the treatment of periodontitis in rats exposed to cigarette smoke inhalation (CSI). Ligatures were placed in the maxillary second molars. After a 15-day period, the ligatures were removed and 180 animals were randomly divided into six groups: (1) CSRP group--CSI and manual scaling and root planing (SRP) treatment; (2) CL group--CSI and Er,Cr:YSGG laser irradiation; (3) CSRP + L group-CSI, SRP, and Er,Cr:YSGG irradiation; (4) SRP group-manual SRP; (5) L group--Er,Cr:YSGG irradiation; (6) SRP + L group--SRP and Er,Cr:YSGG irradiation. At 7, 15, and 30 days after treatments, animals were euthanized and histologic, histometric, immunohistochemistry, and real-time PCR analyses were performed. Histometrically, no differences were observed in the SRP, L, and SRP + L groups exposed to CSI. The CSRP group showed more bone formation at 30 days than at 15 days (p < 0.01) but less bone at 30 days than the CL group at 30 days (p < 0.05). Immunohistochemical staining was positive for osteoblasts, fibroblasts, and osteoclasts. Real-time PCR showed more (vascular endothelial growth factor) VEGF expression in the L (p < 0.05) and SRP + L (p < 0.01) groups at 30 days than at 15 days and less VEGF expression in the CSRP group at 30 days than at 15 days (p < 0.05). There was no difference in fibroblast growth factor (FGF) expression. The Er,Cr:YSGG laser irradiation promotes favorable conditions for tissue repair even in animals exposed to CSI, with similar results as those achieved from manual scaling and root planing.

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.

Avaliação dos efeitos do laser Er, Cr: YSGG em defeitos ósseos críticos e no tratamento de doença periodontal induzida em ratos submetidos a inalação de fumaça de cigarro / Evaluation of the effects of Er, Cr: YSGG laser in critical bone defects and treatment of periodontal disease induced in rats subjected to inhalation of cigarette smoke

O objetivo deste trabalho foi avaliar as influências do laser Er,Cr:YSGG na criação e reparo de defeitos críticos e no tratamento de doença periodontal em ratos submetidos a inalação de fumaça de cigarro. Utilizou-se 180 ratos, divididos em 6 grupos: Fumante Raspagem (FRAR) - inalação de fumaça de cigarro (IFC), indução da doença periodontal (IDP), e tratamento com raspagem e alisamento radicular (RAR); Fumante Laser (FL) - IFC, IDP e irradiação com o laser de Er,Cr:YSGG (Laser); Fumante Raspagem + Laser (FRAR+L) - IFC, IDP e tratamento com RAR+Laser; Raspagem (RAR) ­ IDP e RAR; Laser (L) ­ IDP e Laser; Raspagem + Laser (RAR+L) ­ IDP e RAR+ Laser. Os resultados histométricos mostraram que em todos os grupos avaliados houve tendência a formação óssea ao longo dos períodos, no entanto essa diferença foi significante apenas no grupo FRAR, comparando os períodos de 15 e 30 dias (p<0,05). A comparação intergrupos mostrou que no período de 15 dias, grupo FL a porcentagem de área óssea foi maior no grupo FL em relação ao grupo FRAR. Nenhuma diferença significante foi observada nos grupos não expostos a inalação de fumaça de cigarro. Na reação por PCR-tempo real, os grupos L e RAR+L mostraram maior expressão de VEGF aos 30 dias (p<0,05) comparados aos 15 dias (p<0,01). O grupo FRAR mostrou menor expressão de VEGF aos 30 dias (p<0,05) em relação aos 15 dias. Para criação dos defeitos, 100 ratos foram divididos em 4 grupos: GT: criação do defeito com trefina; GL: defeito criado com o laser; GFT: IFC e criação do defeito com trefina; GFL: IFC e criação de defeito com o laser. Histometricamente, o defeito foi menor no grupo trefina aos 30 e 60 dias em relação ao período inicial (p<0,05). No grupo laser essa diminuição ocorreu aos 15, 30 e 60 dias comparados ao período inicial (p<0,05, p<0,01, p<0,001) e aos 30 e 60 dias em relação aos 7 dias (p<0,05 e p<0,01). Nos animais expostos a inalação de fumaça de cigarro, houve maior reparo no grupo laser comparado ao trefina no período de 60 dias (p<0,001), dentro do grupo trefina houve diminuição no comprimento do defeito aos 30 dias comparado aos 7 dias (p<0.05) e no grupo laser essa diminuição foi observada nos períodos de 15 (p<0.05), 30 (p<0.05) e 60 dias (p<0.01) em relação aos períodos de 0 e 7 dias. Concluiu-se que o laser de Er,Cr:YSGG associado ou não a raspagem e alisamento radicular (RAR) promoveu condições favoráveis ao reparo tecidual e quando utilizado na criação dos defeitos críticos em calota, este laser proporcionou cortes precisos sem causar danos térmicos aos tecidos subjacentes, favorecendo o reparo na região, independente da exposição a fumaça de cigarro

The aim of this study was to evaluate the influence of the Er, Cr: YSGG laser in criticalsize defects and in the treatment of periodontal disease in rats subjected to cigarette smoke inhalation. It was used 180 rats divided into 6 groups: Cigarette Smoke scaling (CSRP) - cigarette smoke inhalation (CSI), induction of periodontal disease (IPD) and scaling and root planing (SRP); Cigarette Smoke Laser (CL) ­ CSI, IPD and Er,Cr:YSGG laser irradiation; Cigarette Smoke SRP+Laser (CSRP+L) ­ CSI, IPD and RAR + Laser; Scaling and root planning (SRP) IPD, SRP; Laser (L) ­ IPD and Laser; Scaling and root planning + Laser (SRP+L) ­ IPD and SRP followed by Laser. The histometric results showed that in all groups analyzed it was observed a tendency to bone formation over the periods, however this difference was only significant in the CSRP comparing 15 and 30 days (p<0,05). The intergroup comparison showed that the 15-day period, the percentage of bone area was greater in the FL group compared to FRAR group. No difference was observed in the groups not exposed to cigarette smoke inhalation. In reaction by real-time PCR, L and SRP + L groups showed higher expression of VEGF at 30 days (p <0.05) compared to 15 days (p <0.01). The FRAR group showed lower expression of VEGF at 30 days (p<0.05) compared to 15 days. For creation of the defects, 100 rats were divided into 4 groups: GT: creation of the defect with trephine; GL: defect created with the laser; GFT: IFC and creation of defect with trephine; GFL: IFC and creating defect with the laser. The results showed that histometrically, the defect was lower in the trephine group at 30 and 60 days compared to the initial period (p <0.05). In the laser group this decrease occurred at 15, 30 and 60 days compared to the initial period (p <0.05, p <0.01, p <0.001) and at 30 and 60 days compared to 7 days (p <0, 05 and p <0.01). In animals exposed to cigarette smoke inhalation, there was a higher repair in the laser group compared to trephine in 60 days (p <0.001). Intragroupu analysis showed that in the trephine group there was a decrease in the length of the defect at day 30 compared to day 7 (p <0.05). This decrease in the laser group was observed at 15 (p <0.05), 30 (p <0.05), and 60 days (p <0, 01) compared to 0 and 7 days. It was concluded that the Er, Cr: YSGG laser with or without scaling and root planing (SRP) promoted favorable conditions for tissue repair and when used in the critical size defects creation, this laser provided precise cuts without causing thermal damage to surrounded tissues, favoring the repair in the region, regardless of exposure to cigarette smoke inhalation

Chitosan-based biomaterials used in critical-size bone defects: radiographic study in rat's calvaria / Biomateriais a base de quitosana na correção de defeitos ósseos críticos criados em calvaria de ratos: avaliação radiográfica

Objetivo: Este estudo avaliou através de imagens radiográficas digitais, a ação de biomateriais de quitosana e de cloridrato de quitosana, com baixo e alto peso molecular, utilizados na correção de defeitos ósseos de tamanho crítico (DOTC)em calvária de ratos. Material e MétodoO: DOTCs com 8 mm de diâmetro foram criados cirurgicamente na calvária de 50 ratos Holtzman. Em 10 animais o defeito foi preenchido foram preenchidos com coágulo sanguíneo (controle negativo). Os 40 animais restantes foram divididos de acordo com o biomaterial utilizado no preenchimento do defeito (quitosana de baixo peso e de alto peso molecular, e cloridrato de quitosana de baixo e de alto peso molecular), e foram avaliados em dois períodos experimentais (15 e 60 dias), totalizando 5 animais/biomaterial/período de avaliação. Resultado: A avaliação radiográfica foi feita utilizando duas radiografias digitais do crânio do animal: uma tomada logo após o defeito ósseo ser criado e a outra no momento do sacrifício. Nessas imagens, foi avaliada a densidade óssea radiográfica inicial e a final na área do defeito, que foram comparadas. As análises na densidade óssea radiográfica indicaram aumento da densidade óssea radiográfica dos DOTCs tratados para todos os biomateriais testados, em ambos os períodos. Resultados semelhantes foram encontrados no grupo controle. Conclusão: Conclui-se que os biomateriais de quitosana testados não foram capazes de aumentar a densidade radiográfica em DOTC realizados em calvária de ratos.

Objective: This study evaluated, using digital radiographic images, the action of chitosan and chitosan hydrochloride biomaterials, with both low and high molecular weight, used in the correction of critical-size bone defects (CSBD's) in rat's calvaria. Material and Method: CSBD's with 8 mm in diameter were surgically created in the calvaria of 50 Holtzman rats and these were filled with a blood clot (Control), low molecular weight chitosan, high molecular weight chitosan, low molecular weight chitosan hydrochloride and high molecular weight chitosan hydrochloride, for a total of 10 animals, which were divided into two experimental periods (15 and 60 days), for each biomaterial. The radiographic evaluation was made using two digital radiographs of the animal's skull: one taken right after the bone defect was created and the other at the moment of the sacrifice, providing the initial and the final radiographic bone density in the area of the defect, which were compared. Result: Analysis of radiographic bone density indicated that the increase in the radiographic bone density of the CSBD's treated with the proposed biomaterials, in either molecular weight, in both observed periods, where similar to those found in control group. Conclusion: Tested chitosan-based biomaterials were not able to enhance the radiographic density in the CSBD's made in rat's calvaria.

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.

Influence of the angle of irradiation of the Er,Cr:YSGG laser on the morphology, attachment of blood components, roughness, and root wear: in vitro study.

BACKGROUND AND OBJECTIVES: To evaluate the influence of the working tip angulation of the Er,Cr:YSGG laser on the morphology, attachment of blood components, roughness, and wear on irradiated root surfaces compared to scaling and root planing (SRP). STUDY DESIGN/MATERIALS AND METHODS: The present study used 45 teeth, of which 25 were used for the analysis of the morphology and the attachment of blood components and 20 were used for the analysis of the roughness and of the root wear. The teeth were randomly divided into five groups according to the treatment applied: (G1) Laser Er,Cr:YSGG-30°; (G2) Laser Er,Cr:YSGG-45°; (G3) Laser Er,Cr:YSGG-60°; (G4) Laser Er,Cr:YSGG-90°; and (G5) SRP. RESULTS: The root surfaces irradiated with the Er,Cr:YSGG laser working angulation tip of 45° and 60°, and the samples scaled with manual instruments presented greater attachment of blood components than the group where the Er,Cr:YSGG laser irradiated at working tip angulation of 30° and 90° (P<0.05). The samples irradiated with the Er,Cr:YSGG laser were rougher than the samples scaled with manual instruments (P<0.05). The group that was irradiated with the Er,Cr:YSGG laser at an angle of 30° presented the least wear in comparison to all the other treatments (P<0.01). CONCLUSIONS: The irradiated root surfaces proved to be rougher than those scaled with manual instruments; however, irradiation at working tip angulations of 45° and 60° produced results of attachment of blood components and root wear comparable with those obtained with manual instrumentation.

Effect of toothbrushing with different manual toothbrushes on the shear bond strength of orthodontic brackets.

The aim of this study was to evaluate the effect of brushing with a Colgate 360º or Oral B Indicator 35 toothbrush on the shear bond strength of orthodontic brackets bonded to extracted human teeth. The bristle wear and bristle tip morphology were also examined after simulated tooth-brushing. Orthodontic brackets (Roth-P/1st and 2nd premolar S/D- Slot 0.18") were bonded (Transbond XT) to the smoothest surface of each of 45 extracted human molar and premolar teeth. Test specimens were randomly divided into three groups: Group 1, control group with no brushing; Group 2, brushing with the Oral B Indicator 35; Group 3, brushing with the Colgate 360º. Samples were adapted to a machine that simulated tooth-brushing. The bond strength of each bracket to each tooth was assessed with a mechanical testing machine. The bristle wear and bristle tip morphology indices were also assessed. Statistically significant differences were defined for p < 0.05. The average bond strengths (range: 90.18-90.89 kgf/cm²) did not differ among the three groups. The Colgate 360º showed less bristle wear and a better bristle tip morphology than the Oral B Indicator 35 toothbrush. However, use of either toothbrush did not decrease the bond strength of the orthodontic brackets. Therefore, patients undergoing orthodontic therapy can safely use either toothbrush.

Effect of toothbrushing with different manual toothbrushes on the shear bond strength of orthodontic brackets

The aim of this study was to evaluate the effect of brushing with a Colgate 360º or Oral B Indicator 35 toothbrush on the shear bond strength of orthodontic brackets bonded to extracted human teeth. The bristle wear and bristle tip morphology were also examined after simulated tooth-brushing. Orthodontic brackets (Roth-P/1st and 2nd premolar S/D- Slot 0.18") were bonded (Transbond XT®) to the smoothest surface of each of 45 extracted human molar and premolar teeth. Test specimens were randomly divided into three groups: Group 1, control group with no brushing; Group 2, brushing with the Oral B Indicator 35; Group 3, brushing with the Colgate 360º. Samples were adapted to a machine that simulated tooth-brushing. The bond strength of each bracket to each tooth was assessed with a mechanical testing machine. The bristle wear and bristle tip morphology indices were also assessed. Statistically significant differences were defined for p < 0.05. The average bond strengths (range: 90.18-90.89 kgf/cm²) did not differ among the three groups. The Colgate 360º showed less bristle wear and a better bristle tip morphology than the Oral B Indicator 35 toothbrush. However, use of either toothbrush did not decrease the bond strength of the orthodontic brackets. Therefore, patients undergoing orthodontic therapy can safely use either toothbrush.

Histological evaluation of chitosan-based biomaterials used for the correction of critical size defects in rat's calvaria.

Chitosan, a biopolymer obtained from chitin, and its derivates, such as chitosan hydrochloride, has been reported as wound healing accelerators and as possible bone substitutes for tissue engineering, and therefore these substances could be relevant in dentistry and periodontology. The purpose of this investigation was to make a histological evaluation of chitosan and chitosan hydrochloride biomaterials (gels) used in the correction of critical size bone defects made in rat's calvaria. Bone defects of 8 mm in diameter were surgically created in the calvaria of 50 Holtzman (Rattus norvegicus) rats and filled with blood clot (control), low molecular weight chitosan, high molecular weight chitosan, low molecular weight chitosan hydrochloride, and high molecular weight chitosan hydrochloride, numbering 10 animals, divided into two experimental periods (15 and 60 days), for each biomaterial. The histological evaluation was made based on the morphology of the new-formed tissues in defect's region, and the results indicated that there was no statistical difference between the groups when the new bone formation in the entire defect's area were compared (p > 0.05) and, except in the control groups, assorted degrees of inflammation could be seen. In conclusion, chitosan and chitosan hydrochloride biomaterials used in this study were not able to promote new bone formation in critical size defects made in rat's calvaria.

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.