PURPOSE:To evaluate argon laser irradiation (AL), light-emitting diode exposure (LED), and acidulated phosphate fluoride treatment (APF) in vitro effects on caries-like enamel caries formation. METHODS:Sound teeth (n = 18) were divided into four tooth quarters and coated with an acid-resistant varnish, leaving an enamel window exposed per tooth quarter. The tooth quarters were assigned to: (1) no treatment (control, mesiobuccal); (2) 1.23% APF (4 minutes, distolingual); (3) LED (Ultradent Ultra-Lume LED2 20 seconds, mesiolingual); and (4) AL (HGM Model 8, 11.5 J/cm2, 231 mW, 5mm beam size, 10 seconds, distobuccal). Following caries-like lesion formation (modified ten Cate solution), longitudinal sections (three per tooth quarter, 54 lesions per group) were obtained and evaluated for mean lesion depths (water imbibition, polarized light microscopy, ANOVA, DMR). RESULTS:Mean lesion depths were: 198 +/- 21 microm for controls; 186 +/- 17 microm for LED; 117 +/- 19 microm for AL; and 104 +/- 23 microm for APF. Lesion depths were statistically significantly decreased for AL (41%) and APF (47%) groups (P < 0.05), compared with controls. A slight lesion depth reduction for LED (6%) was present compared with controls; however this was not statistically significantly different (P > 0.05).

OBJECTIVEThis clinical pilot study was conducted to investigate the effectiveness of argon laser irradiation to reduce demineralization or loss of tooth structure in vivo.SUMMARY BACKGROUND DATAIn vitro research previously demonstrated the ability of argon laser irradiation to reduce demineralization or loss of tooth structure.METHODSUsing the Ogaard model of producing demineralization, the experimental teeth were irradiated with argon laser of 250 mW (producing approximately 12 J/cm2) prior to banding. Polarized light evaluation of the sectioned, extracted teeth was used to determine the amount of demineralization.RESULTSResults showed a 29.1% reduction in demineralization in the experimental teeth as compared to the bilateral control teeth.CONCLUSIONLow-power argon laser irradiation significantly reduced demineralization clinically.

This in vitro study compared the effects of visible light and argon laser polymerization of pit and fissure sealants on surface topography and the enamel-sealant interface. Twenty caries-free human molars and premolars underwent soft tissue debridement and a fluoride-free prophylaxis. Fluoride-releasing sealant (UltraSeal XT Plus, South Jordan, UT 84095) was placed on the occlusal surfaces per the manufacturer's instructions, but underwent either visible-light polymerization for 30s (n = 10), or argon laser polymerization (0.231 J/cm2) for 10s (n = 10). The sealed teeth were thermocycled (500 cycles, 5 degrees to 50 degrees C) in artificial saliva. Surface morphology was evaluated by SEM. The teeth were sectioned for polarized light and SEM evaluation of the enamel-sealant interface, with two sections per tooth prepared for SEM. Phosphoric acid was used to unmask the enamel-sealant interface with one section; while the other section was not exposed to the phosphoric acid. Surface morphology of the sealant material was similar with both visible light and argon laser polymerization; however, there was a tendency for occasional areas of mild, focal cratering of the sealant surface with laser-curing. The junction between sealant and adjacent unsealed enamel was a relatively smooth transition without gaps, microspaces, crazing, exfoliative changes, or microfractures with both visible light and laser cured sealants. Acid treatment of the sections revealed resin tags which extended into the adjacent enamel for a considerable distance on SEM examination. The resin tas were similar in length and morphology with both visible light and argon laser curing. The enamel-sealant interface with visible light and laser curing showed intimate contact between the sealant and etched occlusal enamel with close apposition of the sealant. No microspaces were identified between the sealant and the occlusal enamel. An intact, interdigitating interface between a sealant and the adjacent etched enamel provides the first line of defense against a cariogenic challenge. Visible-light and argon laser curing allows for an intimate enamel-sealant interface without microspaces and protects sealed enamel from cariogenic challenges. The benefit of argon laser polymerization, fluoride release and mechanical protection of sealant material may provide improved caries resistance in sealed pits and fissures and adjacent nonsealed enamel surfaces.

OBJECTIVEThe purpose of this in vitro scanning electron microscopy (SEM) study was to evaluate the effects of combining low fluence argon laser (AL) irradiation and acidulated phosphate fluoride (APF) treatment on the surface morphology of sound human root surfaces.SUMMARY BACKGROUND DATAPrevious in vitro investigations have shown that combined APF and AL irradiation of root surfaces provided a protective effect against cariogenic challenges.MATERIALS AND METHODSTwelve extracted human molars were sectioned into quarters, and each quarter assigned to 1 of 4 treatment groups: (1) no treatment/control; (2) low fluence (11.5 J/cm2) AL irradiation; (3) 1.23% APF for 4 minutes; (4) APF treatment followed by low fluence AL irradiation. Surface morphology alterations were compared among groups using SEM techniques.RESULTSAL irradiation alone produced irregular textured surfaces with adherent globular material and fine microporsities in the background. APF treatment, alternatively, only created relatively smooth surface coatings that masked the original underlying root surface. Combining APF treatment followed by AL irradiation resulted in a surface coating composed of relatively small (2 to 3 microns) spherical to avoid precipitates, morphologically resembling calcium fluoride.CONCLUSIONCombining APF with AL irradiation may create a more reactive surface that possesses fluoride-rich mineral deposits and protects the underlying root surface from cariogenic challenges.

OBJECTIVE:The purpose of this in vitro scanning electron microscopy (SEM) study was to evaluate the effect of low fluence (energy density of 11.5 J/cm2 and 100 J/cm2) argon laser irradiation on the surface morphology of sound root surfaces.SUMMARY BACKGROUND DATA:Previous laboratory investigations have shown that argon laser irradiation of root surfaces provided a protective effect against in vitro cariogenic challenges.METHODS:Root surfaces of extracted human molars were sectioned into treatment quarters: 1) mesiobuccal--no treatment control; 2) mesiolingual--low fluence argon laser irradiation (0.231 Watts, 11.5 J/cm2 for 10 seconds); 3) distobuccal--no treatment control; and 4) distolingual--higher fluence argon laser irradiation (2.0 Watts, 100 J/cm2 for 10 seconds). All surfaces were critical-point dried, coated with platinum and paladium under vacuum, and evaluated qualitatively for intactness, surface morphology, surface deposits, and porosities in a blinded fashion by scanning electron microscope.RESULTS:The argon lased root surfaces demonstrated alterations of root surfaces with creation of surface globular particulate material, microporosities, and depressions. Both low- and high-fluence lased root surfaces showed areas with plaque-like plates with fine punctuate oval particulate material on their surfaces.CONCLUSIONS:Argon laser irradiated root surfaces produce surface granular to globular deposits that may provide readily mobilized tooth mineral, which may become redeposited into the underlying root surface during a cariogenic challenge and enhance resistance to caries formation. In addition, microporosities created by the argon laser may provide a means for bonding fluoride-releasing restorative and preventive materials to root surfaces and further improve the root surfaces' ability to resist cariogenic challenges.

Because the numbers of dentate elderly are increasing, root caries prevention has become a great concern to the dental profession. This in vitro study evaluates the influence of combining low fluence argon laser treatment and acidulated phosphate fluoride treatment on caries initiation and progression in human root surfaces. The combination of low energy laser treatment and fluoride treatment increased the caries resistance of root surfaces when compared with no treatment and with laser irradiation treatment alone.

Argon laser irradiation (ALI) at relatively low fluences (energy densities) enhances the caries resistance of sound enamel. The purpose of this SEM study was to compare the effects of argon laser irradiation at relatively low fluences (11.5 Joules/cm2 and 100 Joules/cm2) on enamel surface morphology. Following a fluoride-free prophylaxis, 12 extracted caries-free human molars were sectioned into tooth quarters. Tooth quarters were treated as follows: 1) Mesiobuccal-ALI at 11.5 J/J/cm2 for 10; 2) Distobuccal-Control; 3) Mesiolingual-ALI at 100 J/J/cm2 for 10; and 4) Distolingual-Control. Enamel surface morphology was compared among the two argon laser irradiation groups and matched non-treated control enamel surfaces by SEM. Argon laser treatment resulted in considerable alterations in the surface morphology compared with matched controls. Control enamel surfaces showed relatively smooth contours with occasional termination of enamel prisms at the surface. Both argon laser treatment groups had intact enamel surfaces lacking prism end markings and cratering of the enamel surface. A discontinuous granular surface permeated by numerous microporosities of < 1.0 micron in diameter was created with both argon laser treatment groups. Globular deposits of approximately 0.5 to 2 microns in maximum dimension composed the surface coatings. These deposits were admixed with areas of fine microporosities. Argon laser irradiation at relatively low fluences produces surface coatings which may act as reservoirs for mineral phases during an acidogenic attach of the enamel and may provide a certain degree of protection against a cariogenic challenge.

The purpose of this in vitro study was to determine the combined effects of argon laser irradiation (ArI) and acidulated phosphate fluoride treatment (APF) on caries-like lesion formation in human enamel. Each specimen was divided into tooth quarters with each quarter assigned to one of four groups: 1) control; 2) ArI Only; 3) ArI before APF treatment; 4) APF treatment before ArI. After a fluoride-free prophylaxis, acid-resistant varnish was applied to the tooth quarters, leaving sound enamel windows exposed on buccal and lingual surfaces. Argon laser irradiation was at 2 watts for 10s (100J/cm2). APF treatment was with a 1.23% APF gel for 4 min. Lesions were created in sound enamel windows with an acidified gel. After lesion formation, sections were obtained and imbibed with water for polarized light study. Body of the lesion depths were determined and compared among the four groups. Lesion depths were: 195 +/- 23 microns for control; 129 +/- 17 microns for ArI only; 96 +/- 14 microns for ArI before APF; and 88 +/- 11 microns for APF before ArI. Significant differences (P < 0.05) were found between the control group and all treatment groups, and between the ArI only group and both combined APF and ArI groups. Significant difference (P > 0.05) was not found between the ArI before APF and the APF before ArI groups. Laser irradiation alone reduced lesion depth by 34% compared with control lesions. When ArI was combined with APF treatment, lesion depth decreased by more than 50% compared with control lesions, and by 26 to 32% when compared with lased-only lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

The aim of this study was to evaluate the effect of low fluence argon laser (AL) and acidulated phosphate fluoride (APF) treatment on caries initiation (CI) and progression (CP) in human enamel. Twenty caries-free molars were divided into tooth quarters. Tooth quarters from each specimen were assigned to one of four groups: 1) Control; 2) AL Only; 3) AL before APF; 4) APF before AL. AL was at 0.25 watts for 10 seconds (12.0 +/- 0.5 J/cm2). APF treatment was with a 1.23% gel for 4 minutes. Lesions were created in two treated, sound enamel windows per tooth quarter with an acidified gel. After CI and CP, sections were obtained and imbibed with water for polarized light study. Mean body of the lesion (BL) depths were determined and compared among groups (ANOVA & DMR). After CI, BL depths were: 189 +/- 29 micrometers for Control, 133 +/- 23 micrometers for AL only; 91 +/- 17 micrometers for AL before APF; and 83 +/- 14 micrometers for APF before AL. After CP, BL depths were: 321 +/- 43 micrometers for Control, 206 +/- 35 micrometers for AL only; 118 +/- 21 micrometers for AL before APF; and 114 +/- 19 micrometers for APF before AL. After CI and CP, argon laser irradiation alone resulted in significant reductions in lesion depth when compared with controls (p<0.05). APF treatment before or after argon laser exposure resulted in a significant reduction in lesion depth when compared with AL alone or control groups (p<0.05). Caries initiation and progression in vitro are affected to a significant extent when low fluence (energy) argon laser irradiation of sound enamel alone or in conjunction with APF treatment is done. This caries-protective effect occurs at an argon laser fluence (energy) that is capable of polymerizing visible light-cured resins.

PURPOSE:To determine the effects of argon laser irradiation (ArI) and topical acidulated phosphate fluoride (APF) treatment on artificial caries formation in root surfaces. MATERIALS AND METHODS:After soft tissue debridement and fluoride-free prophylaxis, the teeth were divided into quarters and acid-resistant varnish was applied, leaving windows of sound root surface exposed. Each tooth received four separate treatments: (1) Control-mesiobuccal quarter; (2) ArI only--mesiolingual quarter; (3) ArI followed by APF- distobuccal quarter; (4) APF followed by ArI-distolingual quarter. ArI was for 10 seconds at 2W (100J/cm2) and APF treatment was for 4 minutes. After artificial lesion formation, sections were prepared and evaluated with polarized light. Mean lesion depths were determined and compared (ANOVA & DMR for a paired design). RESULTS:Mean lesion depths were: 347 +/- 41 microns--controls; 263 +/- 32 microns--ArI only; 158 +/- 21 microns--ArI followed by APF; and 149 +/- 17 microns -APF followed by ArI. Lesion depths were significantly different (P < 0.05) between the control group and each treatment group, and between ArI only group and either combined APF and ArI groups. No lesion depth difference (P > 0.05) was present between the combined APF and ArI groups. Argon laser irradiation significantly enhanced the resistance of root surfaces to demineralization. Combination of APF treatment with argon laser irradiation provided added protection against a constant artificial caries attack.

Recent research shows that laser irradiation can improve enamel's resistance to caries. This invitro study examines the effects of argon laser irradiation on root surface caries. Treated surfaces seemed more resistant to an artificial caries medium than control surfaces.

This study evaluated and compared the effects of argon laser and visible light polymerization of a pit and fissure sealant material on caries-like lesion initiation and progression. Following the lesion initiation period, the primary surface lesion depth was significantly less (P < 0.05) for the argon laser-cured group (97 microns) when compared with that for the visible light-cured group (151 microns). Wall lesion occurrence was 5% for both treatment groups. Following lesion progression, the primary surface lesion depth was significantly less (P < 0.05) for the argon laser-cured group (129 microns) when compared with that for the visible light-cured group (232 microns). Wall lesion occurrence was 15% and 5% for visible light-cured and argon laser-cured groups, respectively (P < 0.05). Argon laser-curing of sealant material may enhance the caries resistance of the enamel forming the enamel-resin interface and result in a reduction in caries formation adjacent to sealants.

There has been a recent resurgence of interest in the role of lasers in prevention and treatment of enamel and dentinal caries. At relatively high energy levels, it is possible to produce a surface melt and effectively seal an enamel or dentinal surface, while producing only a 4-degrees-C increase in pulpal temperature. In this study the depth of the body of the lesion was reduced by 41 percent for those lesions exposed to argon laser irradiation.