ABSTRACT
Objective: To compare the effect of three surface treatment protocols and two intermediate agents on repairing aged composite, regarding microtensile bond strength (µTBS) and mode of fracture, at two time intervals. Material and methods: Six-monthaged microhybrid composite blocks, were randomly distributed into three groups, subjected to; Fine, Super Fine grit diamond burs or Erbium- Yag Laser surface treatment. Each block had both One Coat bond SL (Bond) and Brilliant Flow flowable composite (Flow) intermediate agents, alongside. Blocks were incrementally repaired using nanohybrid composite, cut into beams, then randomly subjected either immediately (IM) to µTBS test or after thermocycling (TC) for 5000 cycle. Mode of failure was determined using stereomicroscope. Data were analyzed through three-way ANOVA followed by pairwise comparison with Bonferroni correction. Kruskal Wallis test compared groups for failure mode analysis (α=0.05) Results: Super Fine grit showed the highest mean µTBScompared to control for both intermediate agents, IM and after TC at P<0.05. No difference between Fine grit and Laser application for all groups (P>0.05). IM, Bond showed the highest µTBS compared to TC, Flow for all tested groups. Beams roughened with Fine and Super Fine burs showed significantly lower adhesive failures than those roughened with Laser. Flow suffers significantly higher adhesive failure than those with Bond. For TC tested groups; beams with Super Fine bur and Bond showed significantly lower adhesive failure at P=0.029. Conclusion: Super Fine grit and Bond provide the highest µTBS and the least adhesive failure; moreover TC resulted in significant decrease in µTBS (AU)
Objetivo: Comparar o efeito de três protocolos de tratamento de superfície e dois agentes intermediários no reparo de compósito envelhecido, quanto à resistência à microtração (µTBS) e modo de fratura, em dois intervalos de tempo. Material e métodos: Blocos de compósito microhíbrido envelhecidos por seis meses, foram distribuídos aleatoriamente em três grupos, submetidos a; Pontas diamantadas de granulação Fina, Superfina ou tratamento de superfície com laser de Erbio-Yag. Cada bloco tinha ambos os agentes intermediários One Coat bond SL (Adesivo) ao lado de Brilliant Flow (Resina Fluida). Os blocos foram reparados de forma incremental usando compósito nanohíbrido, cortados em palitose, em seguida, submetidos aleatoriamente imediatamente (IM) ao teste de µTBS ou após termociclagem (TC) por 5000 ciclos. O modo de falha foi determinado usando estereomicroscópio. Os dados foram analisados por meio de ANOVA de três fatores, seguida de comparação pareada com correção de Bonferroni. O teste de Kruskal Wallis comparou os grupos para análise do modo de falha (α = 0,05). Resultados: a granulação Super fina apresentou a maior média de µTBS em comparação com o controle para ambos os agentes intermediários, IM e após TC (P <0,05). Não houve diferença entre granulação fina e aplicação de laser para todos os grupos (P> 0,05). IM, Adesivo apresentou a µTBS mais alta em comparação com TC, Resina Fluida para todos os grupos testados. Os palitos asperizados com pontas de granulações Fina e Superfina apresentaram falhas adesivas significativamente menores do que as asperizadas com Laser. Resina Fluida sofreu falhas adesivas significativamente maiores do que aquelas com Adesivo. Para grupos testados TC; palitos tratados com ponta Superfina e Adesivo apresentaram falha adesiva significativamente menor com P = 0,029. Conclusão: a granulação Superfina e o Adesivo fornecem a maior µTBS e o mínimo de falha adesiva; além disso, o TC resultou em uma diminuição significativa da µTBS. (AU)
Subject(s)
Statistics, Nonparametric , Composite Resins , Resin Cements , LasersABSTRACT
BACKGROUND: Treatment of congenital melanocytic nevi (CMN) with intense pulsed light (IPL) has recently produced promising results. OBJECTIVE: To evaluate the clinical and histological outcomes of small-to-medium sized CMN treated with IPL alone and in combination with erbium: yttrium-aluminum-garnet (Er: YAG) laser. METHODS: We performed a retrospective chart review of 26 small-to-medium sized CMN treated as described above. The reduction in visible pigmentation, signs of recurrence and any adverse skin changes were evaluated by two independent clinicians. RESULTS: Seventeen patients completed treatment and were followed-up. Nine were not able to complete treatment due to work, change in residence, and treatment related stress. Ten patients received IPL alone (mean: 10.5 sessions) and 7 underwent treatment with IPL (mean: 7.7 sessions) and Er: YAG/IPL combination therapy (mean: 4.7 sessions). The initial treatment outcome was cleared in 5 patients and excellent in 12. Fourteen patients (82.4%) showed CMN recurrence one year after treatment completion. The histological results from a patient with an excellent clinical outcome showed remnant nevus cells nests in the deep dermis. CONCLUSION: IPL treatment alone and in combination with Er: YAG laser are not definitive treatments for CMN and should not be considered as first-line treatment.
Subject(s)
Humans , Dermis , Erbium , Intense Pulsed Light Therapy , Lasers, Solid-State , Nevus , Nevus, Pigmented , Pigmentation , Recurrence , Retrospective Studies , Skin , Treatment OutcomeABSTRACT
BACKGROUND: Treatment of congenital melanocytic nevi (CMN) with intense pulsed light (IPL) has recently produced promising results. OBJECTIVE: To evaluate the clinical and histological outcomes of small-to-medium sized CMN treated with IPL alone and in combination with erbium: yttrium-aluminum-garnet (Er: YAG) laser. METHODS: We performed a retrospective chart review of 26 small-to-medium sized CMN treated as described above. The reduction in visible pigmentation, signs of recurrence and any adverse skin changes were evaluated by two independent clinicians. RESULTS: Seventeen patients completed treatment and were followed-up. Nine were not able to complete treatment due to work, change in residence, and treatment related stress. Ten patients received IPL alone (mean: 10.5 sessions) and 7 underwent treatment with IPL (mean: 7.7 sessions) and Er: YAG/IPL combination therapy (mean: 4.7 sessions). The initial treatment outcome was cleared in 5 patients and excellent in 12. Fourteen patients (82.4%) showed CMN recurrence one year after treatment completion. The histological results from a patient with an excellent clinical outcome showed remnant nevus cells nests in the deep dermis. CONCLUSION: IPL treatment alone and in combination with Er: YAG laser are not definitive treatments for CMN and should not be considered as first-line treatment.
Subject(s)
Humans , Dermis , Erbium , Intense Pulsed Light Therapy , Lasers, Solid-State , Nevus , Nevus, Pigmented , Pigmentation , Recurrence , Retrospective Studies , Skin , Treatment OutcomeABSTRACT
Background: Striae distensae or stretch marks are atrophic linear dermal scars with epidermal atrophy. There are many therapeutic options for management, but no consistently effective modality is available yet. Objective: We compared the efficacy of 1064 nm long pulse (LP) Nd: YAG laser and 2940 nm variable square pulse (VSP) erbium: YAG laser in the treatment of striae distensae. Methods: Twenty female volunteers (Fitzpatrick skin types II-V) aged between 20 and 40 years with striae (3 patients with the rubra type and 17 with the alba type) were enrolled in the study. The duration of striae ranged from 4 months to 12 years. Lesions were located on the abdomen in all patients except one patient who had striae on the arms and two patients with striae in the lumbar region. Treatments were randomly allocated to both sides of the body in each patient, one side being treated with VSP erbium: YAG laser and the opposite side with LP Nd: YAG laser. All subjects were treated monthly for a total of three treatments. Two 3-mm punch biopsies were obtained from six subjects, both of the same striae, one before the first treatment and one 4 weeks after the last session. Results: Response was evaluated clinically by photographic comparison and was found to be poor in 17 subjects, both on the LP Nd: YAG laser treated side and VSP erbium YAG laser treated side. All these patients had mature lesions (striae distensae alba). Three subjects had a moderate response on both sides; these patients' striae were immature (striae distensae rubra). Histologically, elastic fibers were slightly increased in post-treatment samples compared with pretreatment skin biopsies. Conclusion: We observed no satisfactory clinical improvement in striae distensae alba lesions although histopathological changes were seen. We suggest that variable square pulse Er: YAG and long pulse Nd: YAG lasers are not useful in the treatment of striae distensae alba.
Subject(s)
Adult , Biopsy , Erythema/etiology , Female , Humans , Lasers, Solid-State/therapeutic use , Skin/pathology , Striae Distensae/pathology , Striae Distensae/surgery , Young AdultABSTRACT
BACKGROUND: Hypopigmentation is one of the complications developed after laser resurfacing. There have been few data about hypopigmentation developed after Er: YAG laser resurfacing, especially in darker skin. OBJECTIVE: The objective of this study was to assess the clinical and histopathologic features of hypopigmentation developed after Er: YAG laser resurfacing. METHODS: One hundred and ninety patients have been included in this study. Ninety seven patients were treated with short pulsed Er: YAG laser, 2mm spot sized handpiece at the setting of 12.5-15.0J/cm2. Fifty two patients were treated with variable pulsed Er: YAG laser, 5mm spot sized handpiece at the setting of 7.0-7.5J/cm2 and 7msec pulse duration. Forty one patients were treated with dual mode Er: YAG laser, 4mm spot sized scanner at the setting of 17.5J/cm2 ablation mode and 3.15J/cm2 coagulation mode. Incidence, time of onset, duration of hypopigmentation were evaluated throughout the medical charts and serially checked photographs. Skin biopsy was performed in four patients at the hypopigmentation site for histopathologic and electron microscopic examinations with informed consents. RESULTS: Hypopigmentation was observed in twenty six patients; eight in short pulsed Er: YAG laser, eight in variable pulsed Er: YAG laser, ten in dual mode Er: YAG laser. According to the time of onset of hypopigmentation, twelve patients developed hypopigmentation within one month, five patients in two months, three patients within three months, three patients within four months, two patients within five months, and one patient within six months. Twenty out of twenty six patients recovered skin coloration within six months, and two patients within twelve months. On the other hand, four patients had persisted hypopigmentation for more than one year. Melanosome appeared to be decreased but melanocytes appeared to be present in normal numbers on the histopathologic and electron microscopic examinations. CONCLUSION: Although hypopigmentation is one of the frequent complicaions of Er: YAG laser resurfacing, it is temporary in most cases. Thermal damage due to long pulse duration of laser seems to be a very important factor in inducing hypopigmentation.
Subject(s)
Incidence , BiopsyABSTRACT
BACKGROUND: Laser resurfacing of cutaneous scars, rhytides, and photodamaged skin has become very popular. Pulsed erbium:YAG laser resurfacing has recently come into favor for the treatment of pitted acne scars. OBJECTIVE: This study was designed to investigate the efficacy and safety of pulsed erbium:YAG laser in cutaneous resurfacing of pitted acne scars. METHODS: 100 patients with pitted acne scars were enrolled in this study. All patients were treated by means of a pulsed erbium:YAG laser with a 2 mm handpiece at the setting of 500 to 1000mJ/pulse and fluences used varied between 5-15J/cm2. Photographs of the face were obtained at baseline and 2 week postoperatively. Two weeks after treatment, postoperative care such as applying hydroquinone 4% and tretinoin 0.05% was recommended for 2 to 4 weeks. RESULTS: Out of 100 patients, 20% of patients showed an excellent response, 50% a good response, 21% a fair response and 9% a poor response. After 6 months, erythema had developed in two patients and and three patients had developed postinflammatory hyperpigmentation, hypopigmentation and delayed contact dermatitis. CONCLUSION: Treatment with pulsed erbium:YAG laser shows high efficacy and low morbidity in pitted acne scar resurfacing.
Subject(s)
Humans , Acne Vulgaris , Cicatrix , Dermatitis, Contact , Erythema , Hyperpigmentation , Hypopigmentation , Postoperative Care , Skin , TretinoinABSTRACT
BACKGROUND: Laser resurfacing has beneficial effects for the treatment of several skin conditions. Recently, the pulsed erbium:YAG laser has been shown to be a highly effective treatment for several kinds of pitted facial scars. OBJECTIVE: The purpose of this study was to assess the efficacy and safety of pulsed erbium:YAG laser skin resurfacing at the setting of low or high energy for pitted acne scars. METHODS: 65 patients with pitted acne scars were included in this study. All patients had skin types III or IV. All patients were instructed to use tretinoin cream 0.05% nightly for 2-4 weeks prior to the laser treatment. The pulsed erbium:YAG laser with a 2 mm handpiece at the setting of 500 mJ/pulse, 3.5-5 W in 45 patients and 1,000 mJ/pulse, 7-10 W in 20 patients was used. Two weeks after laser treatment, topical application of hydroquinone 4%, tretinoin 0.05%, and hydrocortisone 1% cream was recommended for 2-4 weeks. Facial photographs were obtained at baseline and 2 week intervals postoperatively. The results of treatment were evaluated for the changes of skin texture and color at 1 month, 3 months, and 6 months. RESULTS: In 45 cases treated with 500 mJ/pulse energy, pitted acne scars were improved about 46.7 % on average and no erythema and postinflammatory hyperpigmentation was observed after 6 months. In 20 cases treated with 1,000 mJ/pulse energy, pitted acne scars were improved about 64% on average and erythema in two patients and postinflammatory hyperpigmentation in one patient were observed after 6 months. CONCLUSION: The results of laser treatment for pitted facial acne scars at the setting of high energy are better than those of laser treatment at the setting of low energy.
Subject(s)
Humans , Acne Vulgaris , Cicatrix , Erbium , Erythema , Hydrocortisone , Hyperpigmentation , Lasers, Solid-State , Skin , TretinoinABSTRACT
Presently, Erbium:YAG laser, which is known as laser for osteotomy, is considered to have good resection effects and to bring about minimum thermal damage. Since studies on this has never been done within the country and left as a field still unexplored, I expect to use this study as experimental data on future use of laser on hard tissue. In this report, both surgical bur(diameter 0.5mm carbide roun bur) and Erbium:YAG laser(100mJ/pulse, 10pulse/sec) was used each on the femur of white mouse and after the same amount of osteotomy, the effect of bone healing on the light microscope was observed and comparative study was made histology. The results are as follows : 1. In the first group (1st day, 3rd day), the osteotomic bone portion of the experimental group was irregular with bone resorption and showed more blood cell infiltration, compared with the control group. 2. At 1 week, bone matrix and immature bone was formed in the peripheral and center of the resection area in the control group. But inthe experimental group, more bone formation was initiated in the peripheral than in the center and showed more infiltration of blood cells and inflammatory cells. 3. At 2 week, bone matrix became mature to have similar density with compact bone and showed new formed vessels in the control group. But in the experimental group, bone formation with decreased density was initiated and new formed vessels together with mature bones was observed. 4. At 3 week, mature bone with equal density and regular trabecular pattern was observed in the control group. But in the experimental group, the continuity between the new bone and old bone was rather loose with decreased maturity, but on the other hand, had even bone formation pattern. 5. At 4 week, both the control and experimental group showed perfect bone healing features. From the results above, I can observe that in osteotomy with Erbium:YAG laser bone healing is rather delayed in each step but if, effective percentage of resection could obtained it would be valuable to substitute mechnical bur or saw and bring about much progress and development in the area of oral and maxillofacial surgery. For this, more studies on bone resection and biomechanical strength of bone tissue after bone healing should be done on various animals.
Subject(s)
Animals , Mice , Blood Cells , Bone and Bones , Bone Matrix , Bone Resorption , Erbium , Femur , Hand , Lasers, Solid-State , Osteogenesis , Osteotomy , Surgery, OralABSTRACT
BACKGROUND: Laser resurfacing has beneficial effects in the treatment of several skin problems such as acne and chicken pox scars. Recently pulsed erbium YAG laser has been used for skin resurfacing, but not enough is known about the scientific basis of such treatment. OBJECTIVE: The purpose of the study was to assess the macroscopic and microscopie changes after irradiation with the pulsed Er-YAG laser. METHODS: We did two tests on guinea pig skin, First, the laser was used to irradiate the skin of a guinea pig with the intensity of 500 mJ, 5 watt until pinpoint bleeding began. Skin biopsies were performed immediately, one, two and four weeks after the irradiation. Second, the laser was used to irradiate the skin of a guinea pig with the intensity of 300mJ(3watt), 500mJ(5watt), 700mJ(7watt) until pinpoint bleeding began, Skin biopsies were examined immediately, one, two and four weeks after the irradiation. RESULTS: 1. Histological changes to the dermis over time after laser irradiation with 500 mJ, 5 watt are as follows: After one week, complete reepithelization and proliferation of the blood vessels within the dermis occured. A reaction of th dermis which consisted of newly formed collagen and was distinguisbed from the lower dermis was also examined. The reaction was rnost active after two weeks and lasted up to four weeks. 2. Histological changes to the dermis over time after laser irradiations with different intensities of 300 mJ(3watt), 500 mJ(5watt), and 700 mJ(7watt) are as follows : In all the cases of laser irradiation with different intensities, edema, neovascularization and fine collagen fiber in the upper dermis were observed. At higher intensities, the dermal reactions were stronger and were sustained for a longer time. CONCLUSION: Pulsed erbium YAG laser had effects on the epidermis and dermis. Therefore, pulsed erbium YAG laser can be used for skin resurfacing effectively and safely.
Subject(s)
Animals , Acne Vulgaris , Biopsy , Blood Vessels , Chickenpox , Cicatrix , Collagen , Dermis , Edema , Epidermis , Erbium , Guinea Pigs , Guinea , Hemorrhage , Lasers, Solid-State , SkinABSTRACT
The present study investigates the effects of the new Erbium:YAG(yttrium aluminum garnet) laser sclerostomy in eight rabbits eyes. The energy was set at 10mJ per pulse with the frequeny of 10Hz, and the total energy for the full thickness sclerostomy procedure was rated at 90 to 150ml. Following the procedure, the mean intraocualar pressure was significantly reduced for up to 7 days, and the histopathological observation at day 7 revealed clearly demarcated wound margins at the resected sites. The sesults suggest that te Erbium:YAG laser sclerostomy may be a good supportive procedures to conventional treatment of glaucoma.