Safety and mechanism of action of noninvasive radiofrequency treatment for vaginal laxity: Histological study in the swine vaginal model.

BACKGROUND: Structural changes in collagen and elastin fiber density have been previously evaluated by qualitative histological studies; however, quantitative evaluations are lacking. AIM: To evaluate quantitative changes in collagen and elastin fibers in the vaginal wall in a porcine model after volumetric radiofrequency heating with an intravaginal applicator. METHODS: An animal model was used (domestic pig, multipara: 5.67 ± 0.94 deliveries, 3 years of age). Three pigs under general anesthesia were treated (8-minute, vaginal canal area) once per week for the course of three weeks. There were 2 follow-up evaluations at one and four weeks. Histology specimens were obtained via punch biopsy under ultrasound control. Ultrasound video measurements of the vaginal wall thickness were also obtained. Tissue samples were stained by H&E as well as stains for collagen and elastin fibers. RESULTS: Elastin (P < .001) and collagen (P < .01) fiber density increased after every treatment. The measured increase in fibers was highest at the one-week follow-up. Elastin accounted on average for 51.46 ± 16.86% of the tissue examined (increase of 36.8% points), while collagen accounted on average for 44.83 ± 18.92% (increase of 17.1% points). The number of synthetically active cells was increased by 16%. While vaginal wall thickness did show an increase of 1.66 mm (32%), this tendency was not statistically significant (P > .05). CONCLUSION: Results suggest that volumetric heating of vaginal tissue produced quantitative improvement in the connective tissue organization in a porcine study. Neocollagenesis and neoelastogenesis were observed with an increased number of synthetically active cells.

Evaluation of the Effects of Er:YAG Laser for the De-Epithelialization of the Palatal Graft in the Treatment of Multiple Gingival Recessions: A Randomized Clinical Trial.

Objective: The purposes of this split-mouth pilot study were to investigate the efficacy of the Er:YAG laser use for the de-epithelialization of the palatal graft in the treatment of the multiple gingival recessions using the bilaminar procedure and also to evaluate the patient-reported esthetic outcomes after 6 months. Materials and methods: Five systemically healthy participants with total 28 bilateral-multiple adjacent maxillary Miller I recessions were included. The treatment was performed with the bilaminar technique [coronally advanced flap (CAF)+de-epithelialized free gingival graft]. De-epithelialization procedure was done with scalpel (control site) or Er:YAG laser (Versawave, Hoya ConBio, San Francisco, CA; 40 hz, 50 mJ/pulse), under water irrigation, noncontact mode (∼1 mm away from the target tissue) in sweeping motion with chisel-type laser (test site). Root coverage and patient-reported outcomes were evaluated at 6 months after the operations. Results: Clinical outcomes of the both treatment sites did not show any statistically significant differences except for the gingival thickness parameter. However, patient-reported outcomes regarding the esthetic appearance of the gingiva was detected in favor of the Er:YAG laser applied sites. Conclusions: Within the limits of the study, it can be concluded that both de-epithelialization techniques were highly effective at 6 months. However, Er:YAG laser-applied grafted sites revealed more uniform and esthetic gingival appearance compared with scalpel-used grafted sites.

Stroma in normal and cancer wound healing.

It is currently believed that stroma, the connective framework of biological tissues, plays a central role in normal wound healing and in cancer. In both these contexts, stromal cellular components such as activated fibroblasts interact with complex protein networks that include growth factors, structural protein or proteinases in order to initiate and sustain an extensive remodelling process. However, although this process is usually spatially and temporally self-limited, it is unregulated in the case of cancer and leads to uncontrolled cell proliferation and invasion within tissues, metastasis and therapeutic resistance. In this review, we outline the role of stroma in normal healing, cancer and post radiotherapy, with a particular focus on the crosstalk between normal or cancer cells and fibroblasts. Understanding these mechanisms is particularly important as several stromal components have been proposed as potential therapeutic targets.

Alveolus soft and bone tissue regeneration after laser biomodulation - a histological study.

Functional and esthetic recovery of the patient after tooth extraction is a concern in the nowadays-dental medicine. Immediate implant placement in fresh sockets in posterior sides of the jaws is difficult because of the high amount of bone loss and the disparity between the diameter of the alveolus and the implant. The objective is to evaluate the effect of laser biomodulation alveolar socket healing process of healthy patients. A number of 36 molars have been extracted due to advanced caries lesions from the same dental arch but on opposite sites. Laser irradiation was performed on one side after extraction; the other side was used as control. An Epic-X laser diode (Biolase) Indium-Gallium-Arsenide-Phosphorus (In-Ga-As-P) 940 nm was used in a continuous mode, 0.9 W, 36 J for 80 seconds, daily exposure, in the first seven days after extraction. Specimens of soft and hard tissue were surgically incised and removed by a 4.4 mm diameter trepan from the extraction sites, eight weeks after the surgical procedure. The specimens were prepared by use of two staining procedures: Hematoxylin-Eosin (HE) and Mallory's trichrome. The prepared slides were examined under Leica DM750 optical microscope, 5× and 10× magnification. Laser biomodulation therapy accelerates bone formation by increasing osteoblastic activity. The histological study demonstrates early new bone formation, the regeneration effects in fresh intact bony alveolus compared with the soft and bone regeneration level of non-treated fresh alveolus. Laser biomodulation therapy accelerates soft tissue regeneration and bone formation.

High doses of laser phototherapy can increase proliferation in melanoma stromal connective tissue.

It is well established that laser phototherapy (LP) is contraindicated directly over cancer cells, due to its bio modulatory effects in cell and blood vessel proliferation. The aim of the present study was to analyze the influence of typical low-level laser therapy (LLLT) and high intensity laser therapy (HILT) and an in-between dose of 9 J on collagen fibers and blood vessels content in melanoma tumors (B16F10) implanted in mice. Melanoma tumor cells were injected in male Balb C mice which were distributed in four groups: control (no irradiated) or irradiated by 3, 9, or 21 J (150; 450, or 1050 J/cm2). LP was performed in daily sessions for 3 days with a InGaAlP-660 nm (mean output: 50 mW, spot size: 2 mm2). Tumor volume was analyzed using (1) picrosirius staining to quantify collagen fibers content and (2) Verhoeff's method to quantify blood vessels content. Tumor growth outcome measured in the 3-J group was not significantly different from controls. Nine and 21-J groups, presented significant and dose-dependent increases in tumor volume. Quantitative analysis of the intensity of collagen fibers and their organization in stroma and peri-tumoral microenvironment showed significant differences between irradiated and control group. Blood vessels count of 21-J group outnumbered the other groups. High doses (≥ 9 J) of LP showed a dose-dependent tumor growth, different collagen fibers characteristics, and eventually blood vessel growth, while a typical LLLT dose (3 J) appeared harmless on melanoma cell activity.

Effect of photobiomodulation on connective tissue remodeling and regeneration of skeletal muscle in elderly rats.

The purpose of this study was to evaluate the effects of low-level laser therapy (LLLT) on morphological aspects, IL-6 and IL-1ß expressions, as well as the distribution and organization of collagen in the tibialis anterior (TA) muscle of elderly rats submitted to cryoinjury. Histological photomicrographs were taken of TA muscles stained with HE and picrosirius red. Immunohistochemistry was used for the evaluation of IL-6 and IL-1ß. Male Wistar rats, aged 20 months, were distributed into three groups: (1) control animals not injured or treated with LLLT (n = 5), (2) cryoinjury without LLLT treatment (n = 15), and (3) cryoinjury treated with infrared LLLT (n = 15). LLLT was applied to the TA 2 h after of the injury induction and consisted of daily applications until the sacrifice (1, 3, and 7 days). The following parameters were used: λ = 780 nm, power density 1 W/cm2, output power 40 mW, 10 s per point, 8 points, and 3.2 J of total energy. In the histomorphological analysis, the treated group exhibited a significant decrease in inflammatory infiltrate (p < 0.001) as well as an increase immature fibers and new blood vessels at 7 days compared to the untreated group (p < 0.05). Furthermore, treatment induced a better collagen distribution and organization at 7 days in comparison to the untreated group (p < 0.05). In conclusion, LLLT demonstrated a modulatory effect on the muscle repair process in elderly animals with regard to the collagen remodeling and morphological aspects of muscle tissue.

New therapeutic option in genitourinary syndrome of menopause: pilot study using microablative fractional radiofrequency / Nova opção terapêutica na síndrome geniturinária da menopausa: estudo piloto utilizando radiofrequência fracionada microablativa

ABSTRACT Objective: To evaluate the clinical response of patients with symptoms of genitourinary syndrome of menopause after application of microablative fractional radiofrequency in the vagina and vaginal introitus. Methods: Fourteen patients with symptoms of genitourinary syndrome of menopause underwent three applications of microablative fractional radiofrequency with a 30-day interval, using the Wavetronic 6000HF-FRAXX device and a fractional vaginal electrode. The questionnaires World Health Organization Quality of Life (for quality of life evaluation), Female Sexual Function Index and Quality of Life Adapted Questionnaire in the Domain of Sexual Satisfaction (for sexual function and satisfaction evaluation) were administered before and after the applications (30 to 60 days after the last procedure), in addition to the satisfaction questionnaire after procedure. Results: There was an increase in almost all dimensions on average in quality of life, with statistical significance only in the health domain. There was a significant improvement in the sexual domains in almost all dimensions. All patients stopped using lubricant during intercourse after treatment. In the satisfaction questionnaire after treatment, we observed that the vast majority felt cured or much better (29% and 64%, respectively, total of 92.6%) and were very satisfied or satisfied (43 and 57%, respectively, total of 100%). The only patient who reported little improvement had an 18-year postmenopausal history and was treatment naïve. Conclusion: Microablative fractional radiofrequency was effective in treating symptoms of vaginal dryness and dyspareunia, and eliminated the use of vaginal lubricant during the period observed. Since this is a pilot study with a small number of patients, further studies are required to corroborate our findings and evaluate the long-term effects of microablative fractional radiofrequency on the vaginal tissue.

RESUMO Objetivo: Avaliar resposta clínica de pacientes com sintomas da síndrome geniturinária da menopausa após aplicação de radiofrequência fracionada microablativa na vagina e no introito vaginal. Métodos: Quatorze pacientes com sintomas de síndrome geniturinária da menopausa foram submetidas a três aplicações de radiofrequência fracionada microablativa com intervalo de 30 dias, utilizando aparelho Wavetronic 6000HF-FRAXX e eletrodo vaginal fracionado. Foram aplicados os questionários World Health Organization Quality of Life (para avaliar qualidade de vida), Female Sexual Function Index e Quality of Life Adapted Questionnaire in the Domain of Sexual Satisfaction (para verificar função sexual e satisfação) antes e depois das aplicações (30 a 60 dias após último procedimento), além do questionário de satisfação após procedimento. Resultados: Na qualidade de vida, houve aumento na média em geral, com significância estatística apenas no quesito saúde. No domínio sexual, houve melhora significativa em quase todas as dimensões. Todas as pacientes cessaram o uso de lubrificante na relação sexual após o tratamento. No questionário de satisfação após tratamento, a maioria se sentiu curada ou muito melhor (29 e 64%, respectivamente; total de 92,6%) e estava muito satisfeita ou satisfeita (43 e 57%, respectivamente; total de 100%). A única paciente que relatou pouca melhora tinha história de 18 anos de pós-menopausa e era virgem de tratamento. Conclusão: Radiofrequência fracionada microablativa foi efetiva em tratar sintomas de ressecamento vaginal e dispareunia, e eliminou o uso de lubrificante vaginal durante o período observado. Por se tratar de estudo piloto com pequena quantidade de pacientes, mais estudos são necessários para corroborar estes achados e avaliar os efeitos a longo prazo da radiofrequência fracionada microablativa no tecido vaginal.

Histological differences in the adherence of connective tissue to laser-treated abutments and standard abutments for dental implants. An experimental pilot study in humans

Background: The goal of the current study is to assess the difference in connective tissue adherence to laser microtextured versus machined titanium abutments. Material and Methods: Six patients were selected and each of them received 2 implants, one combined with a laser treated abutment and one with a machined abutment. After three months, the abutments were retrieved together with their surrounding gingival tissue for histological analysis. Qualitative and quantitative evaluation of microscopical images was performed to assess the presence or absence of adherence between the soft tissues and the abutment, and the percentage of soft tissue adhered to the two different surfaces. Results: Intimate adherence between connective tissue and the laser treated abutments, while on machined abutments no adherence was detected. A significant difference was found in the percentage of surface in contact with soft tissue between both implant abutments p=0.03. Conclusions: Within the limitation of the current study, it can be concluded that connective tissues show enhanced adherence to microtextured abutments compared to machined abutments (AU)

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Lasers in Apicoectomy: A Brief Review.

Since the invention of laser, various applications for lasers in endodontics have been proposed, such as disinfection of the root canal system, canal shaping, pulp diagnosis, and apico-ectomy. One of the major applications of laser in endodontics is apicoectomy. The aim of this article is to review the benefits and drawbacks of laser applications in apicoectomy, including effect on apical seal, effect on dentin permeability, effect on postsurgery pain, effect on crack formation, effect on root-end morphology, effect on treatment outcome, and connective tissue response to laser-treated dentin.

New therapeutic option in genitourinary syndrome of menopause: pilot study using microablative fractional radiofrequency.

OBJECTIVE: To evaluate the clinical response of patients with symptoms of genitourinary syndrome of menopause after application of microablative fractional radiofrequency in the vagina and vaginal introitus. METHODS: Fourteen patients with symptoms of genitourinary syndrome of menopause underwent three applications of microablative fractional radiofrequency with a 30-day interval, using the Wavetronic 6000HF-FRAXX device and a fractional vaginal electrode. The questionnaires World Health Organization Quality of Life (for quality of life evaluation), Female Sexual Function Index and Quality of Life Adapted Questionnaire in the Domain of Sexual Satisfaction (for sexual function and satisfaction evaluation) were administered before and after the applications (30 to 60 days after the last procedure), in addition to the satisfaction questionnaire after procedure. RESULTS: There was an increase in almost all dimensions on average in quality of life, with statistical significance only in the health domain. There was a significant improvement in the sexual domains in almost all dimensions. All patients stopped using lubricant during intercourse after treatment. In the satisfaction questionnaire after treatment, we observed that the vast majority felt cured or much better (29% and 64%, respectively, total of 92.6%) and were very satisfied or satisfied (43 and 57%, respectively, total of 100%). The only patient who reported little improvement had an 18-year postmenopausal history and was treatment naïve. CONCLUSION: Microablative fractional radiofrequency was effective in treating symptoms of vaginal dryness and dyspareunia, and eliminated the use of vaginal lubricant during the period observed. Since this is a pilot study with a small number of patients, further studies are required to corroborate our findings and evaluate the long-term effects of microablative fractional radiofrequency on the vaginal tissue.

Effects of 2100 MHz radio frequency radiation on ductus epididymis tissue in rats.

PURPOSE: The use of mobile phones is widespread since the beginning of 1990s. A great debate exists about the possible damage that the Radio Frequency - RF radiation from mobile phones exerts on different organs. The objective of this study was to investigate the possible histopathological effects of 2100 MHz RF radiation on rat ductus epididymis tissue using a light microscopy and immunohistochemical method after one or two month exposure. MATERIALS AND METHODS: The study was performed on 36 adult Wistar albino rats. 2100 MHz RF radiation was used with a specific absorption rate (SAR) of 0.36 W/kg for 30 min/day, 6 days per week for one or two months. There were 3 groups (n = 6 for each group): one month RF exposed group, two months RF exposed group, and the control group. RESULTS: At the end of the study, the structural changes in ductus epididymis tissue were evaluated. In both 2100 MHz RF exposed groups, the rat ductus epididymis sperm were not observed in some channels, a reduction in sperm density in some of the channels drew an attention. The loss of connective tissue and edematous areas were observed in cross channel interstitial connective tissue. In addition, it was observed that vascularization was highly increased with respect to the control group in cross-channel interstitial connective tissue. CONCLUSION: 2100 MHz RF exposure resulted in some structural changes in the male genital ducts of rats (Tab. 1, Fig. 5, Ref 20).

Influence of low-level laser therapy on the healing process of autogenous bone block grafts in the jaws of systemically nicotine-modified rats: A histomorphometric study.

OBJECTIVE: To analyze the influence of low-level laser therapy (LLLT) on the bone healing process of autogenous bone block grafts installed in nicotine systemically modified rats. METHODS: Seventy-two rats (Wistar) were randomly assigned into 4 groups (n=18). SS-BG: saline application+bone graft. SS-BG/LLLT: saline application+bone graft+LLLT. NIC-BG: nicotine application+bone graft. NIC-BG/LLLT: nicotine application+bone graft+LLLT. After 30days of application of solutions, all animals received autogenous bone block graft in the jaw, with the donation from the parietal bone's calvarial area. Treatment with LLLT was in bed-graft interface, after accommodation of the graft. The animals in each group were sacrificed at 7, 14, and 28days after graft surgery. RESULTS: The histologic analyses of NIC-BG group depicted a delay of osteogenic activity in the recipient bed-graft interface and the irradiation of tissue with LLLT provided better bone healing. The histometric analysis revealed that SS-BG/LLLT and NIC-BG/LLLT groups showed increased bone formation compared to BG-SS and NIC-BG groups, after 14days (SS-BG 24.94%±13.06% versus SS-BG/LLLT 27.53%±19.07% and NIC-BG 14.27%±2.22% versus NIC-BG/LLLT 24.37%±11.93%) and 28days (SS-BG 50.31%±2.69% versus SS-BG/LLLT 58 19%±12.32% and NIC-BG 36.89%±8.40% versus NIC-BG/LLLT 45.81%±6.03%). CONCLUSION: Nicotine harms bone formation in the bed-graft interface and LLLT action can mitigate this.

Prediction of tissue thermal damage.

This paper presents a method to characterize tissue thermal damage by taking into account the thermal-mechanical effect of soft tissues for thermal ablation. This method integrates the bio-heating conduction and non-rigid motion dynamics to describe thermal-mechanical behaviors of soft tissues and further extends the traditional tissue damage model to characterize thermal-mechanical damage of soft tissues. Simulations and comparison analysis demonstrate that the proposed method can effectively predict tissue thermal damage and it also provides reliable guidelines for control of the thermal ablation procedure.

Quantification of adipose volume reduction with a prospective study analyzing the application of external radiofrequency energy and high voltage ultrashort pulse duration electrical fields.

To date, there have been no objective measurements of subcutaneous volume loss following treatments with a noninvasive radiofrequency (RF)-based device. Twenty female patients were treated with a suction-coupled bipolar RF device using external RF energy combined with pulsed electromagnetic RF energy for subcutaneous fat reduction. Parameters followed included weight, Vectra measurements of abdominal circumference and torso volume, and high-definition ultrasound measurements of fat thickness. Measurements were taken before treatment and three times following treatment. Analysis of the measured parameters showed that mean circumference reduction of 2.30 cm was noted at three months post-treatment. Independent volumetric analysis showed a mean subcutaneous volume reduction of 428 cc three months following RF treatment. High-resolution ultrasound fat thickness was reduced by a mean of 39.6% three months following the final BodyFX treatment. Independent and paired-sample t-tests showed a p value of < 0.05. Repeated measures of analysis of covariance (ANCOVA) adjusted for differences in age, as well as height and weight (proxy for body mass index) to minimize individual differences and control for extraneous variables that may affect the pre- and post-treatment results were analyzed. No confounding variables were found. All analyses were conducted using IBM SPSS 21.0.

Comparison of the Effects of Low-Level Laser Therapy and Ozone Therapy on Bone Healing.

This study aims to compare the effect of low-level laser therapy (LLLT) and ozone therapy on the bone healing. Thirty-six adult male Wistar albino rats were used for this study. Monocortical defects were shaped in right femur of all rats. Defects were filled with nano-hydroxyapatite graft. The animals were divided into 3 groups and each group was than divided into 2 subgroups. Then, LLLT with a diode laser was applied to the first group (G1), ozone therapy was applied to the second group (G2), and no treatment was applied to the third group as a control group (G3). Animals were sacrificed after 4th and 8th weeks and the sections were examined to evaluate the density of the inflammation, the formation of connective tissue, the osteogenic potential, and osteocalcin activity. As a result, there were no significant differences among the groups of 4 weeks in terms of new bone formation. In the immunohistochemical assessment, the number of osteocalcin-positive cells was higher in the laser group compared to the other group of 4 weeks; this difference was statistically significant in the LLLT and ozone groups (P < 0.05). Histomorphometric assessment showed that the new bone areas were higher in the LLLT and ozone groups; furthermore, there was a statistically significant difference in the LLLT in comparison with the control group at 8th week (P < 0.05). At the same time immunohistochemical assessment showed that osteocalcin-positive cells were considerably higher in G2 than G1 at 8th week (P < 0.05). The findings of this study may be the result of differences in the number of treatment sessions. Further studies are therefore needed to determine the optimal treatment modality.

A rat model of radiation injury in the mandibular area.

BACKGROUND: Radiation technology focuses on delivering the radiation as precisely as possible to the tumor, nonetheless both acute and long-term damage to surrounding normal tissue may develop. Injuries to the surrounding normal tissue after radiotherapy of head and neck cancer are difficult to manage. An animal model is needed to elucidate good treatment modalities. The aim of this study was to establish a rat model where a certain radiation dose gives reproducible tissue reactions in the mandibular area corresponding to injuries obtained in humans. METHOD: The left mandible of male Sprague Dawley rats was irradiated by external radiotherapy (single fraction 15 Gy, total dose 75 Gy) every second week five times. Endpoint was six weeks after last radiation treatment, and the test group was compared to non-irradiated controls. Morphological alterations of the soft tissues, bone and tooth formation, as well as alterations of salivation, vascularity and collagen content were assessed. An unpaired, non-parametric Mann-Whitney test was used to compare the statistical differences between the groups. RESULTS: Analysis of the soft tissues and mandible within the radiation field revealed severe unilateral alopecia and dermatitis of the skin, extensive inflammation of the submandibular gland with loss of serous secretory cells, hyperkeratinization and dense connective fiber bundles of the gingival tissue, and disturbed tooth development with necrosis of the pulp. Production of saliva and the vascularity of the soft tissues were significantly reduced. Furthermore, the collagen fibril diameter was larger and the collagen network denser compared to non-irradiated control rats. CONCLUSION: We have established an animal model of radiation injury demonstrating physiological and histological changes corresponding to human radiation injuries, which can be used for future therapeutic evaluations.

Oxidation events and skin aging.

The rate of skin aging, or that of tissue in general, is determined by a variable predominance of tissue degeneration over tissue regeneration. This review discusses the role of oxidative events of tissue degeneration and aging in general, and for the skin in particular. The mechanisms involved in intrinsic and extrinsic (photo-) aging are described. Since photoaging is recognized as an important extrinsic aging factor, we put special emphasize on the effects of UV exposure on aging, and its variable influence according to global location and skin type. We here summarise direct photochemical effects of UV on DNA, RNA, proteins and vitamin D, the factors contributing to UV-induced immunosuppression, which may delay aging, the nature and origin of reactive oxygen species (ROS) and reactive nitrogen species (RNS) as indirect contributors for aging, and the consequences of oxidative events for extracellular matrix (ECM) degradation, such as that of collagen. We conclude that conflicting data on studies investigating the validity of the free radical damage theory of aging may reflect variations in the level of ROS induction which is difficult to quantify in vivo, and the lack of targeting of experimental ROS to the relevant cellular compartment. Also mitohormesis, an adaptive response, may arise in vivo to moderate ROS levels, further complicating interpretation of in vivo results. We here describes how skin aging is mediated both directly and indirectly by oxidative degeneration.This review indicates that skin aging events are initiated and often propagated by oxidation events, despite recently recognized adaptive responses to oxidative stress.

Microscopic and ultrastructural modifications of postmenopausal atrophic vaginal mucosa after fractional carbon dioxide laser treatment.

Vaginal atrophy occurring during menopause is closely related to the dramatic decrease in ovarian estrogens due to the loss of follicular activity. Particularly, significant changes occur in the structure of the vaginal mucosa, with consequent impairment of many physiological functions. In this study, carried out on bioptic vaginal mucosa samples from postmenopausal, nonestrogenized women, we present microscopic and ultrastructural modifications of vaginal mucosa following fractional carbon dioxide (CO2) laser treatment. We observed the restoration of the vaginal thick squamous stratified epithelium with a significant storage of glycogen in the epithelial cells and a high degree of glycogen-rich shedding cells at the epithelial surface. Moreover, in the connective tissue constituting the lamina propria, active fibroblasts synthesized new components of the extracellular matrix including collagen and ground substance (extrafibrillar matrix) molecules. Differently from atrophic mucosa, newly-formed papillae of connective tissue indented in the epithelium and typical blood capillaries penetrating inside the papillae, were also observed. Our morphological findings support the effectiveness of fractional CO2 laser application for the restoration of vaginal mucosa structure and related physiological trophism. These findings clearly coupled with striking clinical relief from symptoms suffered by the patients before treatment.

Effects of gamma irradiation on collagen damage and remodeling.

PURPOSE: To evaluate the dose-time dependences of structural changes occurring in collagen within 24 hours to three months after gamma-irradiation at doses from 2-40 Gy in vivo. MATERIALS AND METHODS: Rat's tail tendon was chosen as in vivo model, with its highly ordered collagen structure allowing the changes to be interpreted unambiguously. Macromolecular level (I) was investigated by differential scanning calorimetry (DSC); fibers and bundles level (II) by laser scanning microscopy (LSM), and bulk tissue microstructural level (III) by cross-polarization optical coherence tomography (CP-OCT). RESULTS: For (I), the formation of molecular cross-links and breaks appeared to be a principal mechanism of collagen remodeling, with the cross-links number dependent on radiation dose. Changes on level (II) involved primary, secondary and tertiary bundles splitting in a day and a week after irradiation. Bulk collagen microstructure (III) demonstrated early widening of the interference fringes on CP-OCT images observed to occur in the tendon as result of this splitting. At all three levels, the observed collagen changes demonstrated complete remodeling within ∼ a month following irradiation. CONCLUSION: The time course and dose dependencies of the observed collagen changes at different levels of its hierarchy further contribute to elucidating the role of connective tissue in the radiotherapy process.

Effectiveness of Er:YAG laser-aided fiberotomy and low-level laser therapy in alleviating relapse of rotated incisors.

INTRODUCTION: In this study, we compared the effectiveness of laser-aided circumferential supracrestal fiberotomy (CSF) and low-level laser therapy (LLLT) with conventional CSF in reducing relapse of corrected rotations. METHODS: The study included 24 patients who were at the finishing stage of orthodontic treatment and had at least 1 maxillary incisor with 30° to 70° of rotation before starting therapy. The subjects were divided into 4 groups by treatment: conventional CSF, Er:YAG laser-aided CSF, LLLT, and control. After alginate impressions were taken, the archwire was sectioned from the experimental incisors, and they were allowed to relapse. The second impression was taken 1 month later, and the degree and percentage of relapse were calculated in photographs taken from the dental models. Gingival recession, pocket depth, and pain were also measured in the CSF groups. RESULTS: The mean percentages of relapse were 9.7% in the conventional CSF, 12.7% in the Er:YAG laser-aided CSF, 11.7% in the LLLT, and 27.8% in the control groups. Relapse was significantly greater in the control than the experimental groups (P <0.05), which were not statistically different from each other. The changes in sulcus depth and gingival recession were small and not significantly different among the CSF groups (P >0.05), but pain intensity was greater in subjects who underwent conventional CSF (P = 0.003). CONCLUSIONS: Er:YAG laser-aided CSF proved to be an effective alternative to conventional CSF in reducing rotational relapse. LLLT with excessively high energy density was also as effective as the CSF procedures in alleviating relapse, at least in the short term.