Removal of oral soft tissue pathology with the CO2 laser

As the CO2 laser becomes more widely available in hospitals, the oral and maxillofacial surgeon will have greater opportunity to use it for the treatment of soft tissue pathologies of the mouth. This paper considers the advantages and disadvantages of the instrument together with indications for its use and reviews 118 patients who had 130 oral lesions removed with the CO2 laser.     

Ex vivo microscopic assessment of factors affecting the quality of apical seal created by root-end fillings

AIM: (i) To evaluate the incidence of microcracks around root-end preparations completed with ultrasonic tips and their relationship with the root filling technique and thickness of surrounding dentine. (ii) To investigate the effect of rapid exposure to a water-soluble dye of Intermediate Restorative Material (IRM), Super Ethoxybenzoic Acid (sEBA) and Mineral Trioxide Aggregate (MTA), on the marginal adaptation and microleakage of root-end fillings. (iii) To describe the microstructure of the surface of root-end filling materials. METHODOLOGY: Ninety-two single-rooted teeth were divided into two groups (n = 46) according to the root canal instrumentation/filling techniques. Group 1 consisted of specimens in which canal preparation was completed using a crown-down technique and then filled with the Thermafil system (TF group); Group 2 consisted of specimens in which canal preparation was completed using a step-back technique and lateral condensation (LC group). Following root-end resection and ultrasonic cavity preparation, the samples were further divided into three subgroups (n = 24) for root-end filling with IRM, sEBA or MTA. The ultrasonic preparation time was recorded. Eight teeth were kept as positive and 12 as negative controls. Following immersion in Indian ink for 7 days, all resected root surfaces were evaluated for the presence of microcracks and the cross-sectional area of root-end surface and root-end filling were measured to evaluate the thickness of the dentinal walls. Thereafter, the samples were sectioned longitudinally so as to assess the depth of dye penetration and marginal adaptation of root-end fillings. Negative controls longitudinally sectioned were used to describe microstructural characteristics of the root-end filling materials using scanning electron microscopic (SEM) techniques. RESULTS: Although the thickness of dentinal walls between groups 1 and 2 was similar, the ultrasonic preparation time and number of microcracks were significantly higher (P < 0.001) in the TF group. Both groups had a significant correlation between microcracks and ultrasonic preparation time (P < 0.001). sEBA and IRM had better adaptation and less leakage compared with MTA. A SEM analysis displayed microstructural differences between the root-end filling materials. CONCLUSION: Microcracks can occur independently of the thickness of dentinal walls and may be associated with the prolonged ultrasonic preparation time required for the removal of the root filling during root-end cavity preparation. Although sEBA and IRM had better behaviour than MTA regarding microleakage and marginal adaptation, it is possible that exposure of MTA to a water-soluble dye before achieving full set and its porous microstructure contributed to the results.     

半导体激光手术切除老年患者口腔粘液腺囊肿的临床观察

目的:对比观察半导体激光治疗和普通手术方式治疗老年口腔粘液腺囊肿的疗效.方法:101例患者,随机数法分为试验组和对照组,试验组应用半导体激光手具(波长970nm,6W,10Hz,320μm光纤直径)接触式,局麻下沿肿物包膜外微创切割口腔黏膜表层,完整剥离肿物,局部止血后应用半导体激光低能量疗法(Low Level La...     

Use of the 810 nm diode laser: soft tissue management and orthodontic applications of innovative technology.

Innovative technologies such as the diode laser have provided considerable benefit to dental patients and professionals. Facilitating efficient cutting of tissue and subsequent coagulation, the soft tissue laser enhances tissue healing and can reduce postsurgical complications. Due to the conservative nature of treatment accomplished with the laser this technology is very useful in orthodontic procedures. The diode laser is utilized in both esthetic enhancement of the smile, and treatment management of soft tissue issues that impede efficient orthodontic treatment. Its clinical application will be illustrated in a series of orthodontic cases.     

A comparative study of wound healing following incision with a scalpel,diode laser or Er,Cr:YSGG laser in guinea pig oral mucosa: A histological and immunohistochemical analysis

Abstract

Objective. This study compared wound healing following incisions with either a scalpel, a diode laser or an Er,Cr:YSGG laser in guinea pig oral mucosa. Material and methods. Three types of wound were made randomly with either a stainless-steel scalpel, a diode laser or an Er,Cr:YSGG laser in the buccal mucosa of 24 guinea pigs. Five guinea pigs were sacrificed on each of Days 1, 3, 5 and 7 post-surgery. Four guinea pigs were sacrificed on Day 14 post-surgery. Biopsy samples from each oral mucosa wound were examined using light microscopy and the expression of tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β1 was determined by immunohistochemical staining. The expression of TNF-α and TGF-β1 was evaluated by calculating the percentage of positively stained cells and immunostaining intensity was evaluated using a scale ranging from 0 to 3. Results. Infiltration of inflammatory cells decreased rapidly at Day 5 post-surgery in all three groups of animals. The highest level of TNF-α expression was found at Day 1 post-surgery for the diode laser wounds. The intensity of TNF-α immunostaining was highest at Day 3 post-surgery and lowest at Day 7 post-surgery for all three groups of animals. For the scalpel wounds, a lower level of TGF-β1 expression was seen until Day 3 post-surgery and a higher level from Day 7 post-surgery compared to laser wounds. The intensity of TGF-β1 immunostaining was highest at Day 1 post-surgery for the diode laser wounds. Conclusions. The diode laser is considered a good cutting device for oral mucosa; however, more tissue damage occurs than with the use of a scalpel or an Er,Cr:YSGG laser. Larger studies will be needed before fully endorsing the widespread use of the diode laser.     

Use of soft laser in the treatment of oral symptoms

Due to insufficient casual therapy of oral symptoms of dyniae and pyrosis, we applied infrared soft laser in treatment of patients with those oral symptoms. The laser had a wavelength of 904 nm and a radiation strength of 20 W. The tests were performed on 40 persons with stomatopyrosis and stomatodiniae symptoms, under application of laser through 5 days consecutively with radiation of mucosa lasting 3 minutes on 1 cm2. The testing group was represented by persons exclusively under the laser therapy and the control group was represented by 30 persons, who were under a medicamentose therapy with vasodilatator applied with iontophoresis. By persons with stomatopyrosis and stomatodiniae symptoms analgetic effect was attained through the therapy with the laser already after the first application, and the pain and aches intensity was relieved every day during the therapy, by stomatodinae to complete healing. The obtained differences in the intensity of symptoms before and after the therapy were statistically important. The thermoestesiometric determination of laser efficiency by vasodilatation showed differences which were not important, although the temperature during the therapy has slightly increased for 0.1 degrees C. The soft laser can be used as an effective remedy in the treatment of oral symptoms of stomatopyrosis and stomatodinae.     

Thermal increase in the oral mucosa and in the jawbone during Nd:YAG laser applications. Ex vivo study

Objective: Literature reports bactericidal and biostimulant effects for Nd:YAG laser procedures on bone and oral mucosa but the possible overheating can cause damage to anatomical structures. The aim of the study is the evaluation of thermal increase in different levels of oral tissues: mucosa, periosteum and bone during defocused application of Nd:YAG laser at different parameters. Study Design: Superficial thermal evaluation was performed in pig jaws with a thermal camera device; deep thermal evaluation was realized by 4 thermocouples placed at a subperiosteal level and at 1,2 and 4 mm depth in the jaw bone. Laser applications of 1 minute were performed 5 times (with a pause of 1 minute) on a surface of 4 cm2 with a Nd:YAG laser (VSP mode, 320 micrometer fiber, defocused mode) with different parameters. Temperatures were recorded before and after laser applications and after each pause in order to evaluate also the thermal relaxation of tissues. Results: At submucosal level, mean thermal increase was between 1.1°C and 13.2°C, at 1 mm depth between 1.1°C and 8.5°C, at 2 mm depth between 1.1°C and 6.8°C, at 4 mm depth between 1.0°C and 5.3°C. Temperature decrease during the rest time period was variable between 0°C and 2.5°C. Conclusions: Temperatures reached during clinical procedures with parameters reported in the literature in biostimulation protocols (1.25-2 Watts) for the five minutes of application are not dangerous for biological structures. The decrease in temperature during the rest time period is less considerable in the bone in comparison to oral mucosa. Key words:Nd:YAG laser, thermal increase, thermocouple, thermal camera, low level laser therapy.     

Application of a CO2 laser for oral soft tissue surgery in children in Sri Lanka--introduction of a laser through activities of aid to a developing country

The objective of this study was to clarify the effect of CO2 laser irradiation on oral tissue problems in children in Sri Lanka, through the activities of aid to a developing country by the Japan International Cooperation Agency. This study took about six months, during two times periods: from November 2000 to February 2001, and from July 2001 to October 2001, in the paedodontic clinic of the Faculty of Dental Science, University of Peradeniya, in Sri Lanka. A CO2 laser was used on 48 subjects (51 cases), aged between 1 and 15 years, having main indications for labial frenectomy, frenectomy in ankyloglossia, and excision of mucocele. The results indicated that the CO2 laser had the following advantages. 1. Soft tissue cutting was efficient, with no bleeding, giving a clear operative field during operation. 2. There was no need to use sutures. 3. The surgery itself was simple and less time-consuming. Hence, there was no need for general anesthesia for such cases as tongue tie operation in small children. 4. There was no postsurgical infection. As a result, there was no need for analgesics or antibiotics, as post-surgical pain and infection were prevented. 5. Wound contraction and scarring were decreased or eliminated. Considering the above advantages, the use of a CO2 laser proved to be very safe and effective for soft tissue surgery, especially for children in developing countries such as Sri Lanka.     

The clinical use of the Nd:YAG laser in paediatric dentistry for the removal of oral soft tissue

This article considers the clinical use of the Nd:YAG laser for soft tissue surgery in paediatric dentistry. If the claims made about its performance and properties are true then the Nd:YAG laser should be a very useful additional clinical tool for dentists treating children.     

Effect of radiant heat induced by a diode laser (445 nm) on setting process of glass-ionomer cements monitored by Fourier transform infrared spectroscopy

ObjectivesThe aim of this study was to investigate the effect of thermal energy induced by a diode laser (445 nm) on the setting reactions of conventional glass ionomer cements (GICs) by using Fourier transform infrared spectroscopy (FTIR) and to compare it with that induced by a LED device.MethodsFour GICs were investigated in this study (GlassIonomer FX Ultra, Ketac Universal Aplicap, Equia Fill, and Riva Self Cure). The experimental groups of the study were as follows (n = 5): Group 1 (control) – the specimens after mixing were left to set without any treatment; Group 2 – the specimens were irradiated for 60 s using a LED (Valo?) at 1400 mW/cm² (fluence ～ 1.4 J/cm²); Group 3 – the specimens were also irradiated for 60 s using a diode laser (SIROLaser Blue), which emits at 445 ± 5 nm with average output power of 0.7 W (fluence ～ 1.4 J/cm²). FTIR analysis of the GIC specimens was followed to assess the changes in the COO-/CO ratios of the setting reaction and its progress in time.ResultsBoth laser and LED treatments improved the setting reactions of the GICs compared to the control group (p < 0.05). However, this phenomenon was not observed in all materials implying that it may be material dependent.SignificanceRadiant heat treatments using diode laser or LED may be beneficial for the rate and progress of setting reaction of the conventional GICs. The composition and handling of the materials may be crucial for their final properties and the overall clinical behavior.     

Assessing the outcome of orthognathic surgery by three-dimensional soft tissue analysis

Studies of orthognathic surgery often focus on pre-surgical versus post-surgical changes in facial shape. In contrast, this study provides an innovative comparison between post-surgical and control shape. Forty orthognathic surgery patients were included, who underwent three different types of surgical correction: Le Fort I maxillary advancement, bilateral sagittal split mandibular advancement, and bimaxillary advancement surgery. Control facial images were captured from volunteers from local communities in Glasgow, with patterns of age, sex, and ethnic background that matched those of the surgical patients. Facial models were fitted and Procrustes registration and principal components analysis used to allow quantitative analysis, including the comparison of group mean shape and mean asymmetry. The primary characteristic of the difference in shape was found to be residual mandibular prognathism in the group of female patients who underwent Le Fort I maxillary advancement. Individual cases were assessed against this type of shape difference, using a quantitative scale to aid clinical audit. Analysis of the combined surgical groups provided strong evidence that surgery reduces asymmetry in some parts of the face such as the upper lip region. No evidence was found that mean asymmetry in post-surgical patients is greater than that in controls.