Papers by Friedrich Lampert
In a 16S rRNA gene-directed multiplex PCR, Prevotella intermedia- and Bacteroides forsythus-speci... more In a 16S rRNA gene-directed multiplex PCR, Prevotella intermedia- and Bacteroides forsythus-specific reverse primers were combined with a single conserved forward primer. A 660-bp fragment and an 840-bp fragment that were specific for both species could be amplified simultaneously. A total of 152 clinical samples, subgin- gival plaque and swabs of three different oral mucosae, from 38 periodontitis patients were
Objectives: his study aimed to verify the possibility of introducing ultra-short pulsed lasers (U... more Objectives: his study aimed to verify the possibility of introducing ultra-short pulsed lasers (USPL) in Restorative Dentistry by establishing laser parameters compatible to clinical use, as well as assessing microtensile bond strength of resin composite to irradiated dentin. Methods: Enamel and dentin were irradiated with USLP by varying laser wavelength (355, 532, 1,045, and 1,064 nm), pulse duration (pico and femtoseconds) and irradiation protocols (scanning speed, cooling, pulse repetition rate). Temperature increase, ablation rate and surface morphology were evaluated. The most favorable laser parameters were used for the microtensile bond strength of resin composite to irradiated dentin by using etch-and-rinse and self-etch adhesive systems with different bonding protocols (Clearfil SE Bond with and without Primer, Adper Single Bond with and without acid etching). Results: Dentin and enamel irradiated with infrared pico- and femtosecond lasers presented rough surface without c...
Objective: The aim of this pilot study was to investigate the influence of ascorbic acid on tooth... more Objective: The aim of this pilot study was to investigate the influence of ascorbic acid on tooth discoloration after the use of antimicrobial photodynamic therapy (aPDT) in deep carious lesions. Method: Human extracted carious molars were collected and the ones presenting caries involving at least 2/3 of the dentin depth in X-rays, were included in the study. The teeth were then randomly divided into 3 groups (n=5) receiving different treatments after stepwise caries excavation: G1, standard aPDT treatment; G2, aPDT treatment followed by ascorbic acid (60% w/v solution) application and a negative control group; G3, no treatment. For aPDT, the photosensitizer (blue, phenotiazine chloride) was applied in the cavity for 1min, washed-out with air-water spray (10s) and then laser activated. Laser irradiation (660nm) was done at 6 different points (60s/point, 100 mW/cm2) covering the whole cavity bottom. Standardized images of the remaining dentin were obtained from all samples, using a ...
Journal of dental education, 2013
The aim of this study was to evaluate a recently developed preclinical injection and cavity prepa... more The aim of this study was to evaluate a recently developed preclinical injection and cavity preparation model in local anesthesia. Thirty-three dental students administered an inferior alveolar nerve block injection in the model, followed by preparation on a tooth. The injection was evaluated by three observers, and the feedback from the model was registered. After completion of the practical session, the opinion of the dental students was explored with a ten-item questionnaire. Thirty dental students (91 percent) performed the injection correctly according to the feedback of the model, and twenty-eight students (85 percent) did so according to the expert opinion. The agreement between feedback from the training model and the expert opinion was high. The students were very satisfied with the opportunity to practice with the training model, as indicated by the high scores on each item of the questionnaire. These results suggest that use of this preclinical training model in anesthesi...
Objectives: The aim of the study was to pre-evaluate the potential of the CO2 laser to prevent ca... more Objectives: The aim of the study was to pre-evaluate the potential of the CO2 laser to prevent caries in an animal model. Methods: 16 pathogen-free Sprague-Dawley rats aged 22 days were obtained and divided into 5 groups: G1 (positive control, n=5): receiving antimicrobials, then inoculum of 2x109 Streptococcus mutans cells (4 days) and caries-inducing diet; G2 (negative control, n=2): no antimicrobial pre-treatment, no Streptococcus mutans and no caries-diet; G3 (n=2): as G1 but without antimicrobials prior inoculation; G4 (fluoride, n=3): as G1 but with fluorides; G5 (laser, n=4): as G1 but with CO2 laser irradiation. Antimicrobials: chlorhexidine-digluconate (0.12%, 1st day) and amoxicillin/clavulanic acid (300/75 mg/kg/d, 3 consecutive days). Cariogenic diet: 63% of sucrose. The laser treatment was performed with pulsed CO2 laser (λ=10.6m) at 1J/cm2 (226Hz, 5s) and fluoride treatment with NaF varnish (2.3%F), both on 8th day. Caries was scored by the methods of Keyes, plaque by ...
Journal of Endodontics, 1997
The study evaluates a 16S rDNA directed polymerase chain reaction (PCR) to detect and differentia... more The study evaluates a 16S rDNA directed polymerase chain reaction (PCR) to detect and differentiate bacteria in necrotic root canal samples. The examination focused on species that are fastidious concerning culture or are difficult to differentiate after culturing by biochemical methods. In the described PCR assay, a universal 16S rDNA directed forward primer in combination with a highly specific reversed one was used to amplify taxon specific gene fragments of 230 to 950 bp length. A similar PCR reaction using a universal 16S rDNA reversed primer was also established to demonstrate bacteria in root canal specimens in general. A first application of this method revealed the presence of Actinomycetales-species, Fusobacterium nucleatum, "Streptococcus milleri," and, presumably for the first time described in infected root canals, Bacteroides forsythus. The identity of amplificons was confirmed by generating sequence information and comparison to gene databanks.
Head & Face Medicine, 2010
Background: Quantitative sensory testing (QST) is applied to evaluate somatosensory nerve fiber f... more Background: Quantitative sensory testing (QST) is applied to evaluate somatosensory nerve fiber function in the spinal system. This study uses QST in patients with sensory dysfunctions after oral and maxillofacial surgery.
The aim of this study was to investigate the antibacterial effect of a diode laser in deep root c... more The aim of this study was to investigate the antibacterial effect of a diode laser in deep root canal dentine. The microbial colonization of root canal dentine can lead to failures in conventional endodontic treatment if only an inadequate bacterial reduction is achieved through canal treatment and chemical disinfection. 100 micrometer, 300 micrometer and 500 micrometer bovine dentine slices obtained by longitudinal sections were sterilized and inoculated on one side with an Enterococcus faecalis suspension. Laser radiation was performed on the opposite side with the diode laser, emits light at 810 nm and operates in the continuous wave mode (cw). Radiation was performed using a 400 micrometer tapered fiber tip at an angle of approx. 5 degrees to the surface over a period of 30 s. The output power at the distal end of the tip was 0.6 watt. The bacteria were then eluted through vibration and cultured on blood agar plates. The colony count reflected the antibacterial effect of laser r...
Journal of Clinical Laser Medicine <html_ent glyph="@amp;" ascii="&"/> Surgery, 2004
The aim of this in vitro study was to investigate the antibacterial depth effect of continuous wa... more The aim of this in vitro study was to investigate the antibacterial depth effect of continuous wave laser irradiation with a wavelength of 980 nm in the root canal wall dentin of bovine teeth. Background Data: The long-term success of an endodontic therapy often fails due to remaining bacteria in the root canal or dentin tubules, which cannot be sufficiently eliminated through the classical root canal preparation technique nor through rinsing solutions. Materials and Methods: A total of 102 slices of bovine root dentin of different thicknesses (100, 300 and 500 µm) were prepared. The samples were inoculated from one side with 5 µL of an enterococcus faecalis suspension of defined concentration. Four slices per slice thickness served as a control group; the rest of the 30 slices per thickness were subjected to laser irradiation-10 each of these slices were irradiated with distal outputs of 1.75, 2.3, and 2.8 Watts (W). After drying them for 30 sec, the back of the inoculated dentin slice was irradiated for 32 seconds with a 200-µm fiber optical waveguide under constant movement of the fibers. The remaining bacteria were then detached in NaCl under vibration. The eluate produced by this was-taking account of the degree of dilution-plated out on sheep blood agar plates. After 24 h of incubation, the grown bacterial colonies were able to be counted out and evaluated. By doing so, they were compared with the non-irradiated, but otherwise identically treated control group. Results: With a slice thickness of 100 µm, the 980-nm diode laser achieved a maximum bacterial reduction of 95% at 1.75 W, 96% at 2.3 W, and 97% at 2.8 W. With a slice thickness of 300 µm, a maximum of 77% of the bacteria was destroyed at 1.75 W, 87% at 2.3 W, and 89% at 2.8 W. The maximum bacterial reduction with a slice thickness of 500 µm was 57% at 1.75 W, 66% at 2.3 W, and 86% at 2.8 W. Conclusion: The results of this research show that the 980-nm diode laser can eliminate bacteria that have immigrated deep into the dentin, thus being able to increase the success rate in endodontic therapy. 9 Bactericidal Effect of Diode Laser in Root Canal Wall Dentin 13 FIG. 8. Preparation of the specimen: inoculation with the bacteria suspension. FIG. 9. Laser application on the dentin slides.
Medicina Oral Patología Oral y Cirugia Bucal, 2012
Lasers in Surgery and Medicine, 2001
If there is insufficient bonding to the enamel, the shrinkage of composites that occurs during po... more If there is insufficient bonding to the enamel, the shrinkage of composites that occurs during polymerization can result in a gap between the filling material and the cavity wall. This gap permits the passage of bacteria or their metabolic products and also of various molecules and ions. This leads to hypersensitivity or secondary caries and is thus one of the causes of the failures encountered in composite restorations. The aim of this study was to examine the quality of the margins of composite fillings in Er,Cr:YSGG laser-prepared cavities by means of dye penetration. The results were compared with those of restoration in conventionally prepared and conditioned cavities. To this end, 45 class II cavities in extracted molars were prepared. The teeth were divided into three groups. The first group served as a control group. The cavities were prepared in the classical manner by using a diamond, beveled and subsequently conditioned by the etching method. In group 2, the cavities were prepared and conditioned exclusively with the Er,Cr:YSGG laser. In group 3, laser preparation was supplemented by conditioning of the cavity with phosphoric acid. No significant difference could be found between the classical preparation technique in combination with etching and the laser preparation method with supplementary etching (group 3). The degree of dye penetration was highest in the group undergoing laser-prepared restoration without additional etching (group 2) (Wilcoxon test, P &lt; 0.017). Although it was found in previous studies that there is no significant difference between bond strength of acid etched enamel and Er,Cr:YSGG laser etched enamel, the dye penetration rate differs. On the basis of the results of our study, the additional use of etching after Er,Cr:YSGG laser preparation is recommended as it is used in the classical cavity preparation technique.
Lasers in Surgery and Medicine, 1998
The clinical applications of Nd:YAG lasers on oral soft tissues include a wide field of surgical ... more The clinical applications of Nd:YAG lasers on oral soft tissues include a wide field of surgical and periodontal procedures. This in vitro study focuses on the histological effects of Nd:YAG-laser irradiation on a fibroblast monolayer cell culture especially with regard to thermal damage and cell necrosis. The results of this basic research study provide us with clear power settings for a safe soft tissue laser treatment. Two hundred forty multiwell cell cultures and 24 micro-slide Leighton tubes were laser treated. Laser irradiation was performed with a commercial free-running pulse Nd:YAG laser and a quartz fiber with a diameter of 200 microns on L-929 fibroblast cell cultures. The variable parameters were pulse energy (30-120 mJ), pulse rate (20-100 Hz), power output (1.5-3.0 W), and time of irradiation (10-60 s). The cultures were analyzed with help of vital staining, autoradiography, and cytomorphology examination. Depending on the different settings the laser irradiation caused inhibitions of the DNA metabolism rate and the cell division rate, a degeneratively changed cytomorphology up to cell pyknosis. An increasing pulse energy, pulse rate, or an increased time of irradiation created an extended diameter of the pyknotic cell zone. The laser beam creates an exactly bordered damage between cells. The cells had a very good inherent mobility, but the border between eliminated and unloaded cell zone was sharp, even after an incubation of 24 h. These stable results prove that the laser can be applied up to a micrometer distance. With the help of cell clusters it was proved that the laser beam is also able to eliminate exactly one monolayer. Cells which had been covered by another cell layer (in a cluster) were not eliminated.
Lasers in Medical Science, 2009
The exact mechanism of the ablation of tooth hard tissue with most common wavelengths, which are ... more The exact mechanism of the ablation of tooth hard tissue with most common wavelengths, which are 2,940 nm and 2,780 nm, is not yet clear. There are several different theories, but none of them has yet been established. Concepts and methods of looking at these mechanisms have been based on heat formation and transformation, and mathematical calculations evaluating the outcome of ablation, such as looking at the shape of cuts. This study provides a new concept, which is the monitoring of the direct interactions between laser light, water and enamel, with a high-speed camera. For this purpose, both the above-mentioned wavelengths were examined. Bovine anterior teeth were prepared as thin slices. Each imaged slice had a thickness close to that of the beam diameter so that the ablation effect could be shown in two dimensional pictures. The single images were extracted from the video-clips and then were animated. The following steps, explaining the ablation procedures during each pulse, were seen and reported: (1) low-output energy intensity in the first pulses that did not lead to an ablative effect; (2) bubble formation with higher output energy density; (3) the tooth surface during the pulse was covered with the plume of vapour (comparable with a cloud), and the margins of ablation on the tooth were not clear; (4) when the vapour bubble (cloud) was collapsing, an additional ablative process at the surface could be seen.
Lasers in Medical Science, 2013
This study aimed to evaluate the possibility of introducing ultra-short pulsed lasers (USPL) in r... more This study aimed to evaluate the possibility of introducing ultra-short pulsed lasers (USPL) in restorative dentistry by maintaining the well-known benefits of lasers for caries removal, but also overcoming disadvantages, such as thermal damage of irradiated substrate. USPL ablation of dental hard tissues was investigated in two phases. Phase 1--different wavelengths (355, 532, 1,045, and 1,064 nm), pulse durations (picoseconds and femtoseconds) and irradiation parameters (scanning speed, output power, and pulse repetition rate) were assessed for enamel and dentin. Ablation rate was determined, and the temperature increase measured in real time. Phase 2--the most favorable laser parameters were evaluated to correlate temperature increase to ablation rate and ablation efficiency. The influence of cooling methods (air, air-water spray) on ablation process was further analyzed. All parameters tested provided precise and selective tissue ablation. For all lasers, faster scanning speeds resulted in better interaction and reduced temperature increase. The most adequate results were observed for the 1064-nm ps-laser and the 1045-nm fs-laser. Forced cooling caused moderate changes in temperature increase, but reduced ablation, being considered unnecessary during irradiation with USPL. For dentin, the correlation between temperature increase and ablation efficiency was satisfactory for both pulse durations, while for enamel, the best correlation was observed for fs-laser, independently of the power used. USPL may be suitable for cavity preparation in dentin and enamel, since effective ablation and low temperature increase were observed. If adequate laser parameters are selected, this technique seems to be promising for promoting the laser-assisted, minimally invasive approach.
Lasers in Medical Science, 2008
Different ideas have been presented to describe the mechanism of augmented laser ablation of dent... more Different ideas have been presented to describe the mechanism of augmented laser ablation of dental enamel with different shapes by adding water to the working environment. In this study, the influence of water-laser interaction on the surface of enamel during ablation was investigated at a wavelength of 2.94 μm with different distances between the laser tip and the enamel surface. A motion-control system was used to produce linear incisions uniformly on flat enamel surfaces of bovine anterior teeth, with free-running Er:YAG laser very short pulses (pulse length=90-120 μs, repetition rate=10 pulses per second). Four different output energies (100, 200, 300 and 400 mJ) were radiated on samples under distilled water from different distances (0.5, 0.75, 1, 1.25, 1.75 and 2.00 mm). The tooth slices were prepared with a cutting machine, and the surfaces of the ablated areas were measured with software under a light microscope. The average and standard deviation of all cut areas in different groups were reported. There was no significant difference when using a different pulse ablation speed (cm 3 /J) and a water-layer thickness between the tip and enamel surface of 0.5-1.25 mm with energy densities of 30-60 J/cm 2 (200-400 mJ). However, using an output energy of 15 J/cm 2 (100 mJ) and a thicker water layer than 1 mm, a linear ablation did not take place. This information led to a clearer view of the efficiency of Er:YAG laser in the conditions of this study. There are several hypotheses which describe a hydrokinetic effect of Er,Cr:YSGG. These basic studies could guide us to have a correct attitude regarding hydromechanical effects of water, although the wavelength of 2.78 μm has a better absorption in hydroxyl branch of water molecules. Therefore, our results do not directly interrupt with the series of investigations done with Er,Cr: YSGG. Water propagation and channel formation under water are investigated during the ablation of tooth enamel with the Er:YAG laser from different distances. Comparing the results of this study with the same research done with water/air spray concludes that the bubble formation and channel propagation in water with this wavelength leads to a more symmetric (linear) ablation process with cavitypreparation-recommended parameters.
Lasers in Medical Science, 2010
The aim of this study was to determine the amount of intra-canal dentine removed with an erbium, ... more The aim of this study was to determine the amount of intra-canal dentine removed with an erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser using different endodontic tips and different power settings. Ninety intact extracted bovine teeth were selected as samples. After sectioning the roots and preparing the testing cylinders, we divided the samples into three main groups (A, B, C), with further subdivision of each group to be irradiated with three different powers (1500 mW, 1750 mW and 2000 mW). An Er, Cr:YSGG laser system (2.78 μm, 140 μs, 20 Hz and 65% water to 35% air ratio) was used for irradiation, and the loss of intra-canal dentine mass was calculated by the difference between the initial and final sample masses. Data were analysed with Kolmogorov-Smirnov, analysis of variance (ANOVA) and Tukey tests. At a significance level of α=1%, the results showed statistically significant differences (P< 0.0001) between different tip groups, regarding both the ablation rate and the ablation efficiency criteria. With regard to the three irradiation power settings, statistically significant difference were recorded only between groups C and A, for the ablation rate criteria. The intra-canal ablation ability of the Er,Cr:YSGG laser improved with increasing power and/ or tip diameter. The latter exhibited a stronger influence on ablation rate and efficiency. Laser intra-canal ablation is an important addition to the field of endodontics; nevertheless, further investigations and system improvements are required.
Lasers in Medical Science, 2007
Dentin hypersensitivity (DH) is one of the most common complications that affect patients after p... more Dentin hypersensitivity (DH) is one of the most common complications that affect patients after periodontal therapy. So far, many investigators have successfully used different types of laser on DH treatment. The aim of this study was to evaluate the comparative effect of Nd: YAG laser and Er:YAG laser on human teeth desensitization. A group of nine patients with a total of 63 chronic hypersensitive teeth were selected. Each one of them should at least have three hypersensitive teeth. These teeth were randomly allocated into three groups. Group 1, Nd: YAG laser (1 W, 15 Hz, 60 s, two times); group 2, Er:YAG laser (100 mJ, 3 Hz, 60 s, two times); and group 3 serves as control group without any treatment. Assessment of pain was performed by a visual analysing scale (VAS) after stimulation of sensitive tooth by using the sharp tip of an explorer. This test was performed before treatment, immediately after that and at 1-, 3-and 6-month intervals after treatment by one blinded examiner. Analysis of VAS score between the three groups at the time of treatment did not show any significant difference (p=0.506). However, by using repeated-measurement analysis of variance test, significant differences were seen in the three groups between before-treatment VAS score and after treatment (p<0.0005). This statistically significant difference in the control group demonstrated a placebo effect. However, the effect of using Nd:YAG and Er:YAG lasers was stronger than this placebo effect, so that after removing the effect of the placebo, differences immediately after, 1, 3 and 6 months post treatment between all three groups still were statistically highly significant (p<0.0005). Compared to the Er:YAG laser group, using Nd:YAG laser resulted in a significant reduction of VAS score at each follow-up examination (p<0.0005). Although using Nd:YAG and Er: YAG laser in desensitization of hypersensitive teeth showed a placebo effect limited to a short time, results of this study demonstrated that both of these lasers have an acceptable therapeutic effect. The observed effects seemed to last for at least 6 months. It was concluded that Nd:YAG laser is more effective than Er:YAG laser in reduction of patients' pain.
Lasers in Medical Science, 2007
It has been emphasized that one of the most valuable treatment objectives in dental practice is t... more It has been emphasized that one of the most valuable treatment objectives in dental practice is to afford the patient a pain-free treatment. By the evolution of the laser applications, the dental committee aimed to achieve this goal without analgesic drugs and painful methods. Orthodontic treatment is one of these concerns, that one of the major components of patient to reject this treatment is the pain accompanied during the different treatment phases. Another great concern of the patient is not to get through prolonged periods of treatment. The aim of this study is to evaluate the effect of the low-level (GaAlAs) diode laser (809 nm, 100 mW) on the canine retraction during an orthodontic movement and to assess pain level during this treatment. A group of 15 adult patients with age ranging from 14 to 23 years attended the orthodontic department at Dental School, Damascus University. The treatment plan for these patients included extraction of the upper and lower first premolars because there was not enough space for a complete alignment or presence of biprotrusion. For each patient, this diagnosis was based on a standard orthodontic documentation with photographs, model casts, cephalometric, panorama, and superior premolar periapical radiographies. The orthodontic treatment was initiated 14 days after the premolar extraction with a standard 18 slot edgewise brackets [Rocky Mountain Company (RMO)]. The canine retraction was accomplished by using prefabricated Ricketts springs (RMO), in both upper and lower jaws. The right side of the upper and lower jaw was chosen to be irradiated with the laser, whereas the left side was considered the control without laser irradiation. The laser was applied with 0-, 3-, 7-, and 14-day intervals. The retraction spring was reactivated on day 21 for all sides. The amount of canine retraction was measured at this stage with a digital electronic caliper (Myoto, Japan) and compared each side of the relative jaw (i.e., upper left canine with upper right canine and lower left canine with lower right canine). The pain level was prompted by a patient questionnaire. The velocity of canine movement was significantly greater in the lased group than in the control group. The pain intensity was also at lower level in the lased group than in the control group throughout the retraction period. Our findings suggest that low-level laser therapy can highly accelerate tooth movement during orthodontic treatment and can also effectively reduce pain level.
Lasers in Medical Science, 2009
This preliminary study was to investigate in vitro the Er,Cr:YSGG laser ablation capability, both... more This preliminary study was to investigate in vitro the Er,Cr:YSGG laser ablation capability, both range (enlargement aspects of laser tips corresponded to conventional endodontic files) and quality (removing of smear layer and opening of dentinal tubules) to clean and shape the root canal for final obturation step. The crowns of 15 extracted multi-rooted posterior human teeth were resected, and then 15 canals were prepared by an Er,Cr:YSGG laser up to 1.5 W (actual power output) using the step-back technique, while the other 15 canals (control) were enlarged conventionally by K-flex file. The results revealed that posterior root-canal preparation could be achieved by laser beam transmitted to the canal using endodontic tips. At a chosen significance level of α=1%, the results showed no significant statistical difference between the two groups (P>0.01). Considering the results of this current study, laser-based root-canal preparation still shows certain limitations, and further improvements are mandatory for higher achievement and better preparation outcomes.
Lasers in Medical Science, 2013
The aim of this study was to analyze the effect of CO(2) laser (10.6 μm) irradiation with 5-μs pu... more The aim of this study was to analyze the effect of CO(2) laser (10.6 μm) irradiation with 5-μs pulse width in prevention of enamel erosion due to citric acid exposure in vitro. One hundred forty-four bovine enamel samples were cut into 5 × 5 × 2-mm-size slabs and polished to obtain plane surfaces. Enamel surfaces were covered with acid-resistant varnish, except for a central area of 2.5 mm in diameter. The samples were divided into four groups (n = 12/group/day): C-control, no treatment; L-CO(2) laser irradiation (0.3 J/cm(2), 5 μs, 226 Hz); F-topical fluoride treatment, 1.25%F(-) (AmF/NaF) for 3 min; and FL-fluoride treatment + CO(2) laser. For erosive demineralization, samples were immersed in 40 ml of citric acid (0.05 M, pH 2.3) for 20 min two times per day during 5 days. After 1, 3, and 5 days, surface loss was measured by digital profilometer. According to the repeated measure ANOVA and post hoc comparisons, all the treatments showed statistically significant reduction of enamel loss as compared to control group, in all investigated times (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001): L (52%,31%,37%); F (28%,24%,29%); FL (73%,55%,57%). Both CO(2) laser irradiation alone (L) and the combined laser-fluoride treatment (FL) caused less enamel loss than the fluoride group (F) in all days (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001 for L in all times; and p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001, p = 0.0220 and p = 0.0051 for F, respectively, at days 1, 3, and 5). Under the conditions of this study, CO(2) laser irradiation (0.3 J/cm(2), 5 μs, 226 Hz) could effectively reduce enamel surface loss due to citric acid exposure, in vitro. This effect was still observed after 5 days of repeated acid exposures.
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Papers by Friedrich Lampert