Influence of Er, Cr: YSGG laser on root dentin submitted to erosive and/or abrasive challenges

Abstract This study evaluated how Er,Cr:YSGG laser, associated or not with 5% fluoride varnish, influences the surface roughness and volume loss of bovine root dentin submitted to erosive and/or abrasive wear. One hundred and twenty dentin specimens were divided into the groups: without preventive treatment (WPT), 5% fluoride varnish (FV); Er,Cr:YSGG laser irradiation (L), and varnish combined with laser (FV + L). The specimens (n = 10) were subdivided into: 1 = erosion (E); 2 = abrasion (A); and 3 = erosion followed by abrasion (E + A). The erosive solution used was a soft-drink (pH = 2.42 at 4ºC) applied in 5-min cycles twice a day for 10d. Abrasive wear involved brushing for 60s with an electric brush (1,600-oscillations/s) at a load of 2.0N. Surface roughness and volume loss were evaluated using a laser scanning confocal microscope. Roughness data were submitted to one-way ANOVA and Tukey post-hoc test. For volume loss, the Kruskal-Wallis and Dunn's post-hoc tests were used (α = 5%). The lowest values of roughness were found in the control areas of all subgroups (p > 0.05). In the experimental area, the [(WPT) + (E+A)] subgroup had a significantly higher roughness (5.712 ± 0.163 μm 2 ) than the other subgroups (p < 0.05). The L and (FV + L) groups had statistically similar roughness, regardless of the type of wear. The (FV + L) group had the lowest volume loss, regardless of the type of wear performed: [(FV + L) + (E)] = 7.5%, [(FV + L) + (A) = 7.3%, and [(FV + L) + (E + A)] = 8.1%. The subgroup [(WPT) + (E + A)] had the highest volume loss (52.3%). The proposed treatments were effective in controlling dentin roughness. Laser irradiation can be an effective method to increase root dentin resistance after challenges and limit problems related to non-carious lesions.

Can Nd: YAG laser irradiated on dentin with non-polymerized adhesives influence the durability of bond strength and micromorfology of hybrid layer? / Pode o laser Nd:YAG irradiado sobre a dentina impregnada com adesivos não polimerizados influenciar na durabilidade da resistência de união e micromorfologia da camada híbrida?

Objetivo: Este estudo avaliou a durabilidade da resistência de união à dentina utilizando adesivo convencional (Single Bond/SB) e auto condicionante(Clearfil SE Bond/CSEB) associados a irradiação do Nd: YAG laser sobre os adesivos não-polimerizados. Esse estudo também avaliou mudanças micromorfológicas da camada híbrida após armazenagem por 12 meses em água. Material e Métodos: incisivos bovinos foram desgastados para expor uma área de dentina e foram divididos em 4 grupos (n = 15): Grupo 1 (controle) - SB + fotopolimerização; Grupo 2 (Controle) - CSEB + fotopolimerização; Grupo 3 (experimental/laser) - SB + laser Nd:YAG (149,28 J/cm2) + fotopolimerização; Grupo 4 (experimental/ laser) - CSEB + laser Nd:YAG (149,28 J/cm2) + fotopolimerização. Os dentes foram restaurados com resina composta e armazenados por 24 h ou 12 meses(12 m), seccionados em palitos e submetidos s a testes de resistência de união à microtração. Dois dentes de cada grupo (n = 2) foram preparados para análise em MEV. Os resultados foram analisados por ANOVA três-fatores (Adesivo, Técnica e Armazenamento) e teste de Tukey (0,05). Resultados: Resultados para interação Adesivo X Técnica X Armazenamento (valores médios MPa): SB/Controle/24 h = 34,05 (± 6,14) a; CSEB/Controle/24 h = 32,12 (± 5,26)a; SB/laser/24 h = 30,54 (± 5,94) a; CSEB/laser/24 h = 29,45 (± 5,11) a; SB/Controle/12 m = 29,36 (± 5,57) a; CSEB/Controle/12 m = 29,09 8,84) a; SB/laser/12 m = 22,06 (± 3,77) b; CSEB/ laser/12 m = 13,35 (± 3,35) c. Conclusão: Análise de MEV mostrou áreas evidentes de alterações micromorfológicas em amostras irradiadas após 12 meses de armazenamento de água com a degradação acelerada da camada híbrida....

Objective: This study evaluated the durability of bond strength to dentin using total-etch (Single Bond /SB) and self-etch (Clearfil SE Bond/CSEB adhesives associated with Nd:YAG laser irradiation through the unpolymerized adhesives. Also, this study evaluated micromorfological chances in hybrid layer after 12 months water storage.Material and Methods: Bovine incisors were worn to expose a dentin area and were divided into 4 groups (n = 15): Group 1 (Control) – SB + photopolymerization; Group 2 (Control) – CSEB + photopolymerization; Group 3 (experimental/laser) - SB + Nd:YAG laser (149.28 J/cm2) + photopolymerization; Group 4 (experimental/laser) – CSEB + Nd:YAG (149.28 J/cm2) + photopolymerization. Composite blocks were fabricated; intact teeth were stored for 24 h or12 months (12 m), sectioned into beams and submitted to microtensile bond strength tests Two teeth from each group (n = 2) were prepared forSEM analysis. Results: For interaction Adhesive X Technique X Storage time the mean values (MPa) were: SB/Control/24h = 34.05(± 6.14)a; CSEB/Control/24h = 32.12(± 5.26)a; SB/laser/24h = 30.54(±5.94)a; CSEB/laser/24 h = 29.45(±5.11)a; SB/Control/12 m = 29.36(± 5.57)a; CSEB/Control/12 m = 29.09(± 8.84)a; SB/laser/12m= 22.06(±3.77)b; CSEB/laser/12 m = 13.35(±3.35)c. Conclusions: SEM showed evident areas o micromorphological alterations on lased samples after 12 months water storage with accelerated degradation of the hybrid layer. Bond strength decreased when dentin irradiated with the Nd:YAG laser through unpolymerized adhesives was storedin water for 12 months.

Localized flap melt after Nd-YAG laser treatment in recurrent post-LASIK epithelial ingrowth / Derretimento localizado de flap após o tratamento por Nd-YAG laser para crescimento epitelial recorrente pós-LASIK

ABSTRACTNeodymium: Yttrium-Aluminum-Garnet (Nd-YAG) laser treatment of epithelial ingrowth was found promising with high success rates in cases of primary post-LASIK epithelial ingrowth. However, the application range of this procedure is not well-known. For the first time, the authors report the outcome of a patient treated with Nd-YAG laser for multiple recurrences of post-laser in situ keratomileusis epithelial ingrowth.

RESUMOO tratamento com laser de neodímio: Ítrio-Alumínio-Granada (do inglês, Nd-YAG Laser) para o crescimento epitelial primário pós-LASIK demonstrou altas taxas de sucesso. No entanto, os limites deste procedimento não são completamente conhecidos. Pela primeira vez, os autores relatam os resultados de um olho tratado com Nd-YAG laser para múltiplo crescimento epitelial pós-LASIK recorrente que desenvolveu um derretimento localizado do flap.

Clinical observation on Nd:YAG laser for treating high-risk patients with anterior capsule contraction after cataract operation / 重庆医学

Objective To observe the clinical effect of anterior capsule relaxing incisions with Nd:YAG laser in treating postop-erative anterior capsule contraction in high-risk cataract patients.Methods 120 high-risk cataract patients with postoperative ante-rior capsule contraction collected from December 2010 to November 2012 were divided into experimental group(performed the ante-rior capsule relaxing incisions on postoperative 3 d)and control group.The anterior capsule opening area was measured immediately after laser operation(baseline),in postoperative 1,3,6 months by using the Scheimpflug video photogeaphy system,and the descent rate of the opening area was simultaneously calculated.The decentration degree and tilt of intraocular lens(IOL),posterior capsule opacification and other complications were also assessed.Results Of the observed 120 cases,40 cases were pseudo posterior capsule stripping syndrome,40 cases were primary angle closure and 40 cases were diabetic retinopathy.There was no statistically signifi-cant difference in the baseline value of the opening area between the experimental group and the control group(P>0.05).In the ca-ses of primary angle closure 1,3,6 months after operation,the anterior capsule opening area in the experimental group was signifi-cantly increased compared with the control group(P0.05),the descent rate of the opening area was significantly diminished(P<0.05).No significant differences were found in the aspects of IOL decen-tration and tilt,posterior capsule opacity,or other complications.Conclusion YAG laser anterior capsule relaxing incisions in the early period after cataract surgery is safe and effective in preventing anterior capsule contraction in high-risk patients.