This PDF file contains the front matter associated with SPIE Proceedings Volume 6843, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

Background and Objective: 6.05-μm-laser is strongly absorbed by means of both the OH bending of water and the amide-I of proteins. In order to prove the usefulness of dentin ablation by laser irradiation with λ = 6.05 μm, we investigated an ablative behavior of bovine dentin without a water spray. Study Design/Materials and Methods: The dehydrated bovine dentin was irradiated without a water spray by the mid-infrared Free Electron Laser at λ = 6.05 μm and λ = 9.7 μm, while varying the laser parameters, such as the incident fluence and the number of pulse. We observed the configurational changes in the irradiated dentin surface using a scanning electron microscope and estimated the removed volume using a laser confocal microscope. Also, we measured the temperature rise using a radiation thermometer and the emission spectrum using a fiber optics spectrometer during laser irradiation. Results: We found the followings: (1) the dentin was ablated by the evaporation of proteins at the maximum temperature rise of ~400 degC; (2) the irradiated dentin surface had dentinal tubules and was not melted; (3) the extent of the ablative behavior was proportional to the laser parameters used; (4) the tensile bonding strength between the irradiated dentin surface and the composite resin was significantly higher than that for Er:YAG laser irradiation. Conclusion: We can conclude that 6.05-μm-laser can thermo-mechanically excise dentin by the evaporation of proteins even without a water spray. We showed the applicability of a 6.05-μm-laser to a non-invasive laser treatment.

Near-IR (NIR) imaging can be used to view the formation of ablation craters during laser ablation since the enamel of the tooth is almost completely transparent near 1310-nm1. Laser ablation craters can be monitored under varying irradiation conditions to assess peripheral thermal and transient-stress induced damage, measure the rate and efficiency of ablation and provide insight into the ablation mechanism. There are fundamental differences in the mechanism of enamel ablation using erbium lasers versus carbon dioxide laser systems due to the nature of the primary absorber and it is necessary to have water present on the tooth surface for efficient ablation at erbium laser wavelengths. In this study, sound human tooth sections of approximately 2-3-mm thickness were irradiated by free running and Q-switched Er:YAG & Er:YSGG lasers under varying conditions with and without a water spray. The incision area in the interior of each sample was imaged using a tungsten-halogen lamp with a band-pass filter centered at 1310-nm combined with an InGaAs area camera with a NIR zoom microscope. Obvious differences in the crater evolution were observed between CO2 and erbium lasers. Ablation stalled after a few laser pulses without a water spray as anticipated. Efficient ablation was re-initiated by resuming the water spray. Micro-fractures were continuously produced apparently driven along prism lines during multi-pulse ablation. These fractures or fissures appeared to merge together as the crater evolved to form the leading edge of the ablation crater. These observations support the proposed thermo-mechanical mechanisms of erbium laser involving the strong mechanical forces generated by selective absorption by water.

Ceramic brackets are an aesthetic substitute for conventional stainless steel brackets in orthodontic patients. However, ceramic brackets are more brittle and have higher bond strengths, which can lead to bracket breakage and enamel damage during classical type of debonding. This study examined the possibility of laser radiation ceramic brackets removing as well as the possible damage of a surface structure of hard dental tissue after this procedure. Two types of lasers were used for the experiments - a laser diode LIMO HLU20F400 generating a wavelength of 808 nm with the maximum output power 20W at the end of the fiber (core diameter 400 &mgr;m, numerical aperture 0.22). As a second source, a diode-pumped Tm:YAP laser system generating a wavelength of 1.9 &mgr;m, with up to 3.8 W maximum output power was chosen. For the investigation, extracted incisors with ceramic brackets were used. In both cases, laser radiation was applied for 0.5 minute at a maximum power of 1 W. Temperature changes of the irradiated tissue was registered by camera Electrophysics PV320. After the interaction experiment, the photo-documentation was prepared by the stereomicroscope Nikon SMZ 2T, Japan. The surface tissue analysis was processed in "low vacuum" (30 Pa) regime without desiccation. This technique was used to record back-scattered electron images. Selecting the appropriate laser, resin, and bracket combination can minimize risks of enamel degradation and make debonding more safe.

The overall objective of our studies is to establish laser conditions that can be used clinically for the prevention or treatment of early carious lesions in dental enamel and dentin. Previous studies have shown that laser irradiation of dental enamel by specific carbon dioxide laser conditions can inhibit subsequent acid dissolution of the dental enamel surface. The purpose of this study was to determine whether irradiation of dentin by a continuous wave 10.6 µm carbon dioxide laser would inhibit acid dissolution. Blocks of human dentin roots (3x3 mm2) were irradiated at 10.6 µm wavelength with power settings of 0.5, 0.75, 1.0, 1.5 and 2.0 watts. A motion controller system was used to ensure uniform irradiation of the entire dentin surface. Surface acid dissolution profiles following irradiation were acquired for the irradiated groups and a non-irradiated control group. Dissolution rates for 0.5 and 0.75 watts were not statistically significant (p>0.05) from the control group, whereas irradiation at 1.0 watts and higher significantly (p<0.05) increased the acid dissolution rate. Considerable surface damage occurred at these higher powers. This study demonstrated that irradiation of dentin by a continuous wave 10.6 µm carbon dioxide but did not decrease the acid dissolution rate, and was detrimental at powers of 1.0 watts and above.

The effect of pulsed CO₂-laser treatments on the microstructure and nanomechanical properties was studied using atomic force microscopy and nanoindentation. The microstructure and roughness of dentin specimens treated by a 9.3 μm CO₂ laser at fluences of 0.5; 0.75; 1.0; and 1.5 J/cm² were evaluated and the elastic modulus and hardness before and after a nine days demin/remin application for laser treatments at 0.75 and 1.5 J/cm² were determined. The hypothesis that CO₂-laser-treatments reduce or inhibit the demineralization process was tested. Surface cracks were observed at fluences of 0.75 J/cm² and higher. Surface roughness increased strongly after laser irradiation and was about 10 times higher at maximum fluence. Mechanical properties profiles from the laser treated surface to sound dentin showed increased modulus and hardness values at dentin surfaces treated, indicating removal of organic phases and reinforcement of the tissue by increased mineral content. Mechanical properties decreased after demin/remin application in all groups and the hardened surface layer disappeared for samples treated at 0.75 J/cm². While increased properties were still observed in the laser affected surface zone for treatments at 1.5 J/cm², demineralization was severe underneath these layers as indicated by a sharp drop in properties. The depth of demineralization was slightly decreased in the laser-treated group compared to the untreated controls. We conclude that CO₂-laser treatments produce dentin surfaces with increased nanomechanical properties. These surface layers do not, however, provide protection against demineralization due to surface cracking and possible delamination. Moreover, the surface cracks induced by the laser-irradiation raise concerns about a clinical potential for caries inhibition in dentin.

In multiple well-controlled laboratory studies enhancing caries resistance of enamel has been successfully reported using short-pulsed 9.6 µm CO2 laser irradiation. The aim of this study was to prove in a short term clinical pilot trial that the use of the CO2 laser will significantly inhibit the formation of carious lesions around orthodontic brackets in vivo in comparison to a non-irradiated control area. Twelve subjects scheduled for extraction of premolars for orthodontic treatment reasons with an average age of 14.6 years were recruited for the 4-week study. Orthodontic brackets were placed on those premolars with a conventional composite resin (Transbond XT, 3M Unitek, REF 712-035) and a defined area next to the bracket was irradiated with a CO2 laser, Pulse System, Inc (PSI) (Model #LPS-500, Los Alamos, New Mexico), wavelength 9.6 &mgr;m, pulse duration 20 &mgr;s, pulse repetition rate 20 Hz, beam diameter 1,100 &mgr;m, average fluence 4.31 +/- 0.11 J/cm2, 20 laser pulses per spot. Premolars were extracted after four weeks for a quantitative assessment of demineralization by cross sectional microhardness testing. The relative mineral loss &Dgr;Z (vol% x µm) for the laser treated enamel was 402 +/- 85 (SE) while the control area showed a significantly higher mineral loss (mean &Dgr;Z 738 +/- 131; P=0.04, unpaired t-test). The laser treatment produced a 46% demineralization inhibition around the orthodontic brackets in comparison to the non-laser treated areas. This study showed, for the first time that a pulsed 9.6 µm CO2 laser works for the prevention of dental caries in the enamel in vital teeth in human mouths.

Pulsed carbon dioxide lasers operating at the highly absorbed 9.3 and 9.6-μm wavelengths with pulse durations in the microsecond range are ideally suited for dental hard tissue modification and removal. The purpose of these studies was to demonstrate that a low cost 9.3-μm CO₂ laser system utilizing low-energy laser pulses (1-5 mJ /pulse) delivered at a high repetition rate (400-Hz) is feasible for removing dental hard tissues. The laser beam was focused to a small spot size to achieve ablative fluence and an integrated/programmable optical scanner was used to scan the laser beam over the desired area for tissue removal. Pulse durations of 35, 60 and 75-μs were employed and the enamel and dentin ablation rate and ablation efficiency was measured. Laser irradiated human and bovine samples were assessed for peripheral thermal and mechanical damage using polarized light microscopy. The heat accumulation during rapid scanning ablation with water-cooling at 400-Hz was monitored using micro-thermocouples. The laser was able to ablate both enamel and dentin without excessive peripheral thermal damage or heat accumulation. These preliminary studies suggest that a low-cost RF excited CO₂ laser used in conjunction with an integrated scanner has considerable potential for application to dental hard tissues.

Laser Welding is an advantageous method of connecting or repairing metal prosthetic frameworks because there are fewer effects of heating on the area surrounding the spot to be welded, and no further procedures, such as those used for conventional soldering, are necessary. Laser welding has been increasingly applied for fabricating the metal frameworks of prostheses and for other procedures, such as recovering the metal ridge and cusp, blocking holes on the occlusal surfaces after excess occlusal adjustment, thickening the metal framework, or adding contact points after excess grinding and adjusting of the crown margins. The objective of this study are represented by investigation and evaluation of three types of soldering compare to laser welding. The method is represented by the laser welding with a pulsed Nd-Yag Laser equipment. Other joints were produced, using three different soldering techniques. These joining areas were investigated for their quality and their corrosion properties. Corrosion attack was confirmed by electron microscopy. The investigations confirm the quality of laser welding. The investigated different laser welding methods revealed minimal corrosion and offers clear-cut advantages compared to the other soldering methods. Dental alloys are subjected to functional influences in the oral cavity and interact with the intraoral enviroment.

Thermal monitoring during laser-irradiated hard tissues is fundamental to enable real time feedback control and automated adjustment of laser power to maintain a constant, predetermined tissue temperature. We present an experimental technique to produce thermal wave generated in human tooth by irradiation of a high power Q-switched Nd:YAG laser operating at 1064 nm, with variable pulse energy in the range of 50-250 mJ/pulse providing laser fluences of 0.4-2 J/cm² for the laser beam with diameter of less than 1 mm, and short pulse duration down to 100 μsec (or 0.1 ms) at FWHM. A comparison of the measured time-dependent thermal wave for normal and carious human tooth using infrared thermal detector is investigated, simultaneously we have measure the photoacoustic response of the sample using piezoelectric transducer. Calculations of the results demonstrate that the faster temperature decay is for caries one with higher thermal conductivity and thermal diffusivity than the normal one. So the normal tooth has the largest absorption coefficient causing a purely surface heating effect, but for the carious one, the heat source resulting from the relatively low absorption coefficient does not resemble surface heating, but describes a heating effect extending some distance into the irradiated material. These results are in good agreement with the simultaneous measured photoacoustic response, so we can differentiate between the normal and carious ones.

The analysis of the surface of teeth is an important field of research and technological development due to the importance of dental pieces in health and aesthetics. The presence of cracks as well as the etching effects on teeth surface, due to different chemical agents, affects not only the appearance of teeth but its integrity. In this work, laser thermography analysis of dental pieces with damage in the form of cracks is presented. The technique consists in the illumination of the surface at the center of the sample, using a 300 mW pulsed solid state laser beam focused with a gradium lens, and monitoring the spatial and temporal distribution of the temperature field. The heating of the sample is monitored using a focal plane array infrared camera, sensitive in the spectral range 7.5-13 μm with a noise equivalent temperature difference of 0.12°C. The data acquisition was performed by the PC firewire port using a PCI-8254R card and a home-made program in Labview 8.0 was used for data acquisition. The images were processed in a home-made linux program to obtain the experimental table values. Our results are compared with position and frequency scans obtained by infrared photothermal radiometry. It is shown that the crack in the tooth appears as an increase in the photothermal signal. In contrast, the thermographic image shows a more detailed structure in which close to the crack the temperature increases, but at the crack the signal falls.

Dental amalgam is being increasingly replaced by Light-activated resin-based dental composites. However, these materials are limited by inefficient setting reactions as a function of depth, constraining the maximum extent of cure and reducing biocompatibility. In this paper we demonstrate a novel metrological tool for dynamic monitoring of refractive index and thickness change through curing resins using spectral-domain optical coherence tomography. We present real-time measurements from pre- to post-cure of a series of un-filled bisphenol-A diglycidyl ether dimethacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA) resins with different inhibitor concentrations. Our results demonstrate that refractive index measurements are sensitive to the extent of cure of such resins and that the inhibitor concentration strongly affects the cure dynamics and final extent of cure.

Scanning, also called digitizing, is the process of gathering the requisite data from an object. Many different technologies are used to collect three dimensional data. They range from mechanical and very slow, to radiation-based and highly-automated. Each technology has its advantages and disadvantages, and their applications and specifications overlap. The aims of this study are represented by establishing a viable method of digitally representing artifacts of dental casts, proposing a suitable scanner and post-processing software and obtaining 3D Models for the dental applications. The method is represented by the scanning procedure made by different scanners as the implicated materials. Scanners are the medium of data capture. 3D scanners aim to measure and record the relative distance between the object's surface and a known point in space. This geometric data is represented in the form of point cloud data. The contact and no contact scanners were presented. The results show that contact scanning procedures uses a touch probe to record the relative position of points on the objects' surface. This procedure is commonly used in Reverse engineering applications. Its merits are represented by efficiency for objects with low geometric surface detail. Disadvantages are represented by time consuming, this procedure being impractical for artifacts digitization. The non contact scanning procedure implies laser scanning (laser triangulation technology) and photogrammetry. As a conclusion it can be drawn that different types of dental structure needs different types of scanning procedures in order to obtain a competitive complex 3D virtual model that can be used in CAD/CAM technologies.

In root canal therapy, complications frequently arise as a result of root fracture or imperfect cleaning of fins and invaginations. To date, there is no imaging method for nondestructive in vivo evaluation of the condition of the root canal, during or after treatment. There is a clinical need for a technique to detect defects before they give rise to complications. In this study we evaluate the ability of optical coherence tomography (OCT) to image root canal walls, and its capacity to identify complicating factors in root canal treatment. While the potential of OCT to identify caries has been explored before, endodontic imaging has not been reported. We imaged extracted lower front teeth after endodontic preparation and correlated these images to histological sections. A 3D OCT pullback scan was made with an endoscopic rotating optical fiber probe inside the root canal. All oval canals, uncleaned fins, risk zones, and one perforation that were detected by histology were also imaged by OCT. As an example of an area where OCT has clinical potential, we present a study of vertical root fracture identification with OCT.

Introduction: New technologies in dental practice, such as laser, have enabled new strategies to be established in dental education. The aim of this study was to analyze the difficulties that dental students encountered with performing surgical incisions using Er:YAG laser (LE), and the morphology of these incisions. Material and Methods: Sixteen undergraduate dental students and ten dental professionals (DP) enrolled at The Master of Science Program in Laser Dentistry were asked to perform 15 incisions using an LE and 15 with a conventional scalpel. The incisions were compared, based on the shape factor (relation between area and perimeter), which was obtained by a digital image system and by a morphometry software. Data was submitted to statistical analysis of variance (p 0.05). Results: Considering the incisions performed by scalpel, DP showed statistically significant differences (p < 0.01) in relation to control group (CG). Considering the LE, all groups showed significant differences (p<0.0001) in relation to CG, especially the DP group. The main laser technical failures were performing an incision that was not in a straight line, without defined borders, using an inconstant cutting speed, and absence of suction and water jet appliances. None of the groups performed adequate incisions using LE. Conclusion: Greater emphasis is required in relating laser therapy practice to the physical properties of laser, particularly for dental professionals that specialize in laser.

Laser removal of dental hard tissue can be combined with optical, spectral or acoustic feedback systems to selectively ablate dental caries and restorative materials. Near-infrared (NIR) imaging has considerable potential for the optical discrimination of sound and demineralized tissue. Last year we successfully demonstrated that near-IR images can be used to guide a CO2 laser ablation system for the selective removal of artificial caries lesions on smooth surfaces. The objective of this study was to test the hypothesis that two-dimensional near-infrared images of natural occlusal caries can be used to guide a CO2 laser for selective removal. Two-dimensional NIR images were acquired at 1310-nm of extracted human molar teeth with occlusal caries. Polarization sensitive optical coherence tomography (PS-OCT) was also used to acquire depth-resolved images of the lesion areas. An imaging processing module was developed to analyze the NIR imaging output and generate optical maps that were used to guide a CO2 laser to selectively remove the lesions at a uniform depth. Post-ablation NIR images were acquired to verify caries removal. Based on the analysis of the NIR images, caries lesions were selectively removed with a CO2 laser while sound tissues were conserved. However, the removal rate varied markedly with the severity of decay and multiple passes were required for caries removal. These initial results are promising but indicate that the selective removal of natural caries is more challenging than the selective removal of artificial lesions due to varying tooth geometry, the highly variable organic/mineral ratio in natural lesions and more complicated lesion structure.

Previous studies have shown that laser irradiation of dental enamel by specific carbon dioxide laser conditions can inhibit subsequent acid dissolution of the dental enamel surface. The purpose of this study was to determine whether similar carbon dioxide laser conditions would have a protective effect on dentin. Blocks of human dentin roots (3x3 mm2) were irradiated at 9.3 µm wavelength with a 15-18 µs pulse duration laser and fluences of 0.50-1.50 J/cm2. A motion controller system was used to ensure uniform irradiation of the entire dentin surface. Surface acid dissolution profiles following irradiation were acquired for the five study groups, control group (Non-irradiated) and four laser-treated groups. Dissolution profiles of low fluence groups (0.50 and 0.75 J/cm2) exhibited similar profiles to the control group. Dissolution profiles of higher fluence groups (1.0 and 1.5 J/cm2) showed an increased dissolution rate over the control group, but these differences were not statistically significant (p>0.05). This study demonstrated that the application of carbon dioxide laser irradiation significantly alters the surface of dentin but did not decrease the acid dissolution rate.

A wavelet multi-component decomposition algorithm has been used for data analysis of micro-Raman spectra from human biological samples. In particular, measurements have been performed on some samples of oral tissue and blood serum from patients affected by pemphigus vulgaris at different stages. Pemphigus is a chronic, autoimmune, blistering disease of the skin and mucous membranes with a potentially fatal outcome. The disease is characterized histologically by intradermal blisters and immunopathologically by the finding of tissue bound and circulating immunoglobulin G (IgG) antibody directed against the cell surface of keratinocytes. More than 150 spectra were measured by means of a Raman confocal microspectrometer apparatus using the 632.8 nm line of a He-Ne laser source. A discrete wavelet transform decomposition method has been applied to the recorded Raman spectra in order to overcome related to low-level signals and the presence of noise and background components due to light scattering and fluorescence. The results indicate that appropriate data processing can contribute to enlarge the medical applications of micro-Raman spectroscopy.

The tooth enamel, because of its hydroxyapatite composition, must present a Raman spectrum with strong polarization anisotropy. Carious lesions of the enamel will produce an alteration of local symmetry and will increase much more scattering of light. This will reduce the anisotropy of the Raman spectra. Because of the difference between high sensitivity to polarization of the 959 cm^-1 Raman peak in sound enamel and low sensitivity in carried enamel, Raman polarized spectroscopy could be a useful method to early detect teeth caries.

The purpose of this study was to assess the potential of polarization sensitive optical coherence tomography (PS-OCT) to measure non-destructively the severity of natural and artificial caries lesions in dentin and determine the efficacy of intervention with anti-caries agents. Although several studies have demonstrated the utility of PS-OCT to image caries lesions in enamel and quantify the lesion severity, only a few studies have focused on lesions in dentin. In this study images of natural root caries lesions on extracted human teeth were acquired with PS-OCT. In addition artificial lesions were produced in dentin after 12 days of exposure to a demineralization solution at a pH of 5.0. Before exposure, three incisions were made on the sample surfaces using Er:YAG laser irradiation and selected areas were treated with topical fluoride. PS-OCT images were acquired using a high power (45-mw) 1310-nm superluminescent diode with a bandwidth of 35-nm. PS-OCT was able to measure demineralization in dentin to a depth of ~ 1 mm. Polarized light microscopy and microradiography were used to measure lesion severity on histological thin sections for comparison. PS-OCT successfully measured the inhibition of demineralization by topical fluoride. Er:YAG laser irradiation did not significantly increase or decrease the rate of dentin demineralization.

Several studies have shown that lasers can be used to modify the surface morphology and chemical composition of tooth enamel to render it less soluble. Other studies have shown that Polarization Sensitive Optical Coherence Tomography (PS-OCT) can be used to non-destructively measure the efficacy of fluoride in inhibiting the development of artificial caries lesions. The purpose of this study was to determine if PS-OCT can be used to measure inhibition of enamel demineralization after CO₂ laser irradiation. Polarized light microscopy and microradiography were used to measure lesion severity on histological thin sections for comparison. PS-OCT was able to measure a significant reduction in the integrated reflectivity due to inhibition by the laser even though the laser modification of the enamel surface caused a slight increase in reflectivity. This study shows that the PS-OCT is well-suited for in vivo measurements of caries inhibition after laser treatments.

The method of laser micro spectral analysis is a method of punctual method of analysis, which permits to investigate small quantity of material, around 0.1 μg. This method permits to establish the content of atoms and molecules. The method permits to make semi-quantitative and quantitative analysis. By this method it is possible to establish trace elements, with concentration of order ppm (parts per million). For atomic UV spectral analysis, intense spectra are produced by the transitions of the metals. The halogens have poor spectra in the UV region. The method is low cost and can be made also with devices adapted for this kind of measurement. By this method we established the curves of concentration distribution for Ca, Mg, P and Zn. These distributions are different of the direction amalgam-nerve duct and on a perpendicular direction to the direction amalgam-nerve duct. We must underline that the method of laser micro spectral analysis gives the possibility to measure the infiltration of due substances in the porous regions of filled tooth.

The microleakage at the interface between the metal infrastructure and the veneering part of the fixed partial dentures are a common problem of aesthetic dentistry. It is possible to use the method of laser microspectral analysis for investigations of microleakage at the metal-veneering material interfaces in fixed partial prostheses. The laser microspectral analysis device LMA-10 (Carl Zeiss, Jena) was used equipped with a diffraction spectrometer PGS-2 (Carl Zeiss, Jena). Different fixed partial dentures were used to determine the microleakage between the metal infrastructure and the veneering material. The distribution of chemical elements at interface infiltration was investigated, making a series of craters and establishing the spectra of the vapours emitted from the craters. Data was gathered in various tables of chemical elements showing the quality and the quantity of microleakage. The laser microspectral analysis is a punctual method of analysis, which allows to investigate small quantities of materials of around 0.1 μg. This method allows to establish the content of atoms and molecules and to perform semi-quantitative and quantitative analysis. By this method it is possible to establish trace elements, i. e. with concentration of ppm (parts per million).

The complete dentures are currently made using different technologies. In order to avoid deficiencies of the prostheses made using the classical technique, several alternative systems and procedures were imagined, directly related to the material used and also to the manufacturing technology. Thus, at the present time, there are several injecting systems and technologies on the market, that use chemoplastic materials, which are heat cured (90-100°C), in dry or wet environment, or cold cured (below 60°C). There are also technologies that plasticize a hard cured material by thermoplastic processing (without any chemical changes) and then inject it into a mold. The purpose of this study was to analyze the existence of possible defects in several dental prostheses using a non invasive method, before their insertion in the mouth. Different dental prostheses, fabricated from various materials were investigated using en-face optical coherence tomography. In order to discover the defects, the scanning was made in three planes, obtaining images at different depths, from 0,01 μm to 2 mm. In several of the investigated prostheses we found defects which may cause their fracture. These defects are totally included in the prostheses material and can not be vizualised with other imagistic methods. In conclusion, en-face OCT is an important investigative tool for the dental practice.

Previous studies have demonstrated that Polarization Sensitive Optical Coherence Tomography (PS-OCT) can be used to image the remineralization of early artificial caries lesions. However, the depth resolution of the imaging system employed in those previous studies was limited and the outer surface structure of the lesions were not resolved as clearly as desired. The purpose of this study was to repeat the earlier remineralization study using a broadband light-source of higher resolution to determine if there can be improved resolution of the remineralized surface zones of the lesions. An all polarization-maintaining fiber based PS-OCT system operating at 1310-nm was used to acquire polarization resolved images of bovine enamel surfaces exposed to a demineralizing solution at pH-4.9 followed by a fluoride containing remineralizing solution at pH-7.0 containing 2-ppm fluoride. The structure of surface zones could be clearly resolved in the samples that remineralized using PS-OCT. PS-OCT measured a significant (p<0.05) reduction in the integrated reflectivity between the severity of the lesions that were exposed to the remineralization solution and those that were not. The lesion depth and mineral loss was also measured with polarized light microscopy and transverse microradiography after sectioning the enamel blocks. These results show that PS-OCT can be used to non-destructively monitor the remineralization potential of anti-caries agents.