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Biomedical subjects

F Garcia-Godoy

Publications and source records attributed to F Garcia-Godoy.

At least 37 records · Page 2Linked to original sources
PubMed1997

Caries progression of white spot lesions sealed with an unfilled resin.

This study evaluated the artificial caries resistance provided to white spot lesions by sealing with an unfilled resin. Twenty extracted molar teeth were coated with an acid-resistant varnish (ARV), except for two 5 mm x 2 mm enamel windows (mesial and distal), and immersed for 5 weeks in an acidified gel brought to a pH of 4.2 with lactic acid. White spot lesions (not frank caries) were created in each window. The teeth were removed from the gel, rinsed and dried. One window was divided into two equal parts; one half was covered with the ARV (Group 1); the other half was not covered (Group 2). The other window was treated with 37% phosphoric acid for 20 sec, rinsed with water for 20 sec, dried and sealed with Prisma Universal Bond 2 Adhesive (Group 3). The teeth were reimmersed in the acidified gel for 40 days until frank caries was induced in Group 2. Specimens were then removed from the gel, rinsed, and sectioned occlusogingivally. Sections were polished to approximately 100 microns, imbibed in water, and analyzed using polarized light microscopy. Depth of demineralization was evaluated in the varnished, sealed and frankly carious areas. The mean (SD) lesion depths were as follows: Group 1 (under ARV) 366 microns (103 microns); Group 2 (frank caries) 746 microns (219 microns); Group 3 (under sealed area) 298 microns (111 microns). ANOVA and Student-Newman-Keuls procedure were used to compare group means. The mean depths of demineralization under the ARV (Group 1) and the unfilled resin sealant (Group 2) were significantly less than for the unprotected enamel (Group 2) (p > 0.0001). Results indicate the potential effectiveness of sealing white spot lesions with an unfilled resin to prevent further demineralization.

Analysis of Variance↗
PubMed1997

Fluoride release from fissure sealants.

This 30-day study, compared the amounts and patterns of fluoride release from 5 commercially available fluoride-containing pit and fissure sealants: FluroShield, Helioseal-F, Ultraseal XT, Baritone L3, and Teethmate-F; Delton without fluoride, was used as control. Disc-shaped samples of each sealant were immersed in distilled water and the fluoride release was measured periodically until day 30. All the fluoridated sealants tested released measurable fluoride throughout the test period in a similar pattern: the greatest amount of fluoride was released in the first 24 hours after mixing, fell sharply on the second day and decreased slowly for the last days. On day one, Baritone L3 released significantly more fluoride than all other materials. Teethmate-F released the highest amount of fluoride during all the other time intervals from day 2, until day 30.

Analysis of Variance↗
PubMed1996

Antibacterial activity of fluoride release sealants on mutans streptococci.

This study was conducted to study the antibacterial activity of sealants on mutans streptococci. The antibacterial effect of fluoride release sealants was estimated by using agar plates infected with several strains of S. mutans and S. sobrinus. Both bacterial groups were sensitive to sealant antibacterial activity, there was not statistical difference in the inhibition between both groups. The Teethmate-F was the only active material in this study and showed more than four times fluoride release than FluoroShield. The inhibition activity was associated with sealant fluoride release after the setting of this material.

Anti-Infective Agents, Local↗
PubMed1996

Fissure micromorphology and sealant adaptation after occlusal enameloplasty.

This study evaluated fissure micromorphology after enameloplasty, and the effect of thermocycling on the adaptation of enamel surfaces of filled and unfilled sealants after different occlusal surface treatments. A total of 150 human noncarious extracted molars were cleaned with a water slurry of fine flour of pumice using Crescent Snap-On pointed brushes in a slow-speed handpiece. The teeth were divided at random into six groups of 20 teeth each: Group 1: Pumice prophylaxis and PrismaShield filled sealant; Group 2: Pumice prophylaxis and Delton opaque unfilled sealant; Group 3: Treatment with a diamond fissure bur (Sorensen Ponta K.G. 2137 F) and PrismaShield sealant; Group 4: Treatment with a diamond fissure bur (Sorensen Ponta K.G. 2137 F) and Delton opaque sealant; Group 5: Treatment with a 1/4 round carbide bur and PrismaShield sealant; Group 6: Treatment with a 1/4 round carbide bur and Delton opaque sealant. Before sealant placement, the enamel occlusal surfaces were acid-etched for 30 seconds using disposable brushes, rinsed and dried. The sealants were light-cured for 40 seconds. Immediately after curing the sealant, all teeth were placed in distilled water for 48 hours. Sixty teeth were thermocycled (x 500, 5 degrees C-55 degrees C, 30-second dwell time) and 60 teeth were not thermocycled. For each treatment modality, five additional teeth served as controls and did not receive the sealant. The results revealed a superior sealant adaptation to enamel when the enameloplasty technique was used. There was no difference in penetration capabilities and adaptation between the filled and the unfilled sealants or between the thermocycled or not thermocycled groups.

Dental Bonding↗
PubMed1995

Resin bonding efficacy of Gluma 2000 to dentine of primary teeth: an in vitro study.

The aim of this study was to investigate (i) the effect of Gluma 2000 conditioning solution on the dentine of primary teeth, (ii) the penetration of Gluma 2000 adhesive resin into the etched dentine, (iii) the shear bond strength of a composite resin restorative material (Pekafill) bonded with Gluma 2000 to dentine, and (iv) the depth of penetration of adhesive resin into the etched dentine as a function of the conditioning time. Dentine surfaces conditioned for 15, 30, 60 and 120 seconds were examined by scanning electron microscopy. The smear layer was totally removed and, with the longer conditioning times, a fine crystalline precipitation, presumably calcium oxalate, was formed. After Gluma 2000 bonding of composite resin and dissolution of the teeth the resin interface showed excellent penetration into the etched dentine. Shear bond strengths of composite resin bonded with the adhesive resin were similar following conditioning for 15, 30, 60 and 120 seconds. Microphotographs of debonded specimens indicated that the mode of failure was cohesive within the resin. The depth of penetration of resin into etched dentine was determined by scanning electron microscopy, and a linear relationship was found between the thickness of the resin-impregnated layer and conditioning time. It was therefore concluded that depth of resin penetration and shear bond strength are not correlated. The study shows that the Gluma 2000 bonding system produces reliable adhesion of composite resin to dentine of primary teeth.

Acid Etching, Dental↗
PubMed1995

Clinical evaluation of the retention and wear of a light-cured pit and fissure glass ionomer sealant.

The purpose of this study was to evaluate the 12-month retention and wear of an experimental light-cured glass ionomer for pit and fissure sealing. A total of 25 patients 7-14 years-old were selected from the Pediatric Dentistry Clinic at the University of Texas Health Science Center at San Antonio. The patients resided in areas without fluoridated water. Each tooth was isolated with cotton rolls, dried with oil-free compressed air and GC Dentin Conditioner applied with a small disposable brush to the pits and fissures for 20 seconds. The teeth were rinsed with water and gently air dried using an air/water syringe. The teeth were not desiccated. GC experimental glass ionomer for pit and fissures was used. The powder/liquid ratio was dispensed at 1.4 gm/1.0 gm (one level spoonful of powder to one drop of liquid). The powder was mixed for 15-20 seconds. An explorer was used to apply the mixed sealant to the tooth and teased into all pits and fissures. The sealant was then cured for 20 seconds. Occlusion was corrected after the sealant was light-cured. Immediately, a color slide and a vinyl polysiloxane impressions were taken. The impressions were poured in epoxy resin. Color slides, impressions and epoxy models were also made at 3, 6, 9 and 12-month recalls. A total of 95 sealants were placed and follow-up for 12 months. The results showed that with the clinical visual inspection all sealants were present at 3 and 6 months postoperatively. At 12 months, only 20% of the sealants were clinically evident.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Acidulated phosphate fluoride treatment and formation of caries-like lesions in enamel: effect of application time.

The aim of this study was to evaluate the effect of acidulated phosphate fluoride (APF) application time (1 and 4 minutes) on caries-like lesion formation in enamel. Following a fluoride-free prophylaxis, the specimens (10 extracted human molars) were divided into tooth quarters and assigned to treatment groups: 1) Distobuccal and Distolingual Quarters--1 minute APF; 2) Mesiobuccal and Mesiolingual Quarters--4 minute APF. Acid-resistant varnish was applied to the tooth quarters, leaving sound enamel windows exposed on buccal and lingual surfaces. Following treatment, the APF gel (Oral-B Minute Gel) was removed by air-water spray rinsing, followed by a 24-hour water rinse. Sound enamel windows protected from APF treatment by acid-resistant varnish were created adjacent to APF-treated sound enamel windows and served as paired controls. Lesions were created in APF-treated and paired control 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 measured and compared statistically. Mean body of the lesion depths were: 186 +/- 28 microns for control lesions, 117 +/- 12 microns for APF-1min; and 111 +/- 14 microns for APF-4min. Significant differences (p < 0.05) were found between paired control and APF groups. No difference (p > 0.05) was found between APF-1min and APF-4min groups. APF treatment prior to lesion formation resulted in a significant reduction in lesion depth, regardless of whether a 1 or 4 minute APF treatment period was used. The 1 minute APF treatment provided the same degree of caries protection as the longer treatment period.

Acidulated Phosphate Fluoride↗
PubMed1995

Shear strength of ceramic brackets bonded to etched or unetched enamel.

The purpose of this study was to compare the shear bond strengths and enamel surface morphology after debonding a polycrystalline ceramic bracket (Transcend 2000) bonded with a light-cured resin cement (Transbond) without enamel etching or by etching for 15 seconds with 10% or 37% phosphoric acid and 10% maleic acid. Forty extracted noncarious human premolars were used. The buccal enamel surfaces were used and the teeth randomly divided in to four groups of 10 teeth each: Group 1: No enamel etching; Group 2: Enamel etching for 15 seconds with 10% phosphoric acid; Group 3: Enamel etching for 15 seconds with 37% phosphoric acid; and Group 4: Enamel etching for 15 seconds with 10% maleic acid. The brackets were bonded to the etched enamel surfaces according to manufacturers' instructions except the etching time variations. All specimens were stored in distilled water for 24 hours and then thermocycled for 300 cycles between 5 degrees C and 55 degrees C. The specimens were mounted in dental stone and placed in the Instron at a crosshead speed of 0.5 mm/min using a knife-edged blade. Immediately after debonding, the enamel surface and bracket-enamel interface were evaluated visually and with a stereomicroscope. Representative samples were then examined with the SEM. ANOVA and Student-Newman-Keuls tests were performed. The results (in MPa) were: Group 1:11.83 (+3.9); Group 2: 28.80 (+12.6); Group 3: 26.25 (+5.3); Group 4: 18.06 (+6.9). Groups 2 and 3 were statistically significantly different (p<0.0001) from Groups 1 and 4. Groups 2 vs. 3 or 1 vs. 4 were not statistically different. Debonding occurred mainly at the bracket-resin interface in all groups, except Group 2 which displayed two samples with enamel cohesive failures and two fracturing the bracket. The SEM evaluation revealed that after debonding, the group etched with the 37% phosphoric acid gel had the roughest enamel surface and was the only group to present enamel fractures. Bracket bonding with unetched enamel and enamel etched with 10% phosphoric acid gel should be clinically investigated using the products tested.

Acid Etching, Dental↗
PubMed1995

Restoration of primary molars with Compoglass.

The initial glass-ionomer cements have become well-known restorative materials and have achieved success in a variety of procedures. The newest generation of glass-ionomer cements contain more resin, have higher cohesive strengths, and are light cured, compared with previous generations. Other fluoride-releasing resins with glass-ionomer properties have been developed, and they are called "compomers." One such recently introduced material is discussed in this article. A clinical case report is presented, illustrating the utilization of this material in the restoration of a mandibular second primary molar.

Composite Resins↗
PubMed1994

Shear bond strength of orthodontic brackets cemented with a zinc oxide-polyvinyl cement.

The purpose of this study was to compare the shear bond strengths and enamel surface structure after debonding a conventional metal bracket and a polycrystalline ceramic bracket bonded with a bipolar zinc oxide-polyvinyl cement (F-21) or a light-cured resin cement (Transbond). Forty extracted human premolars were used. The buccal enamel surfaces were used, and the teeth randomly divided into four groups of 10 teeth each: group 1: conventional metal bracket (Unitek) bonded with Transbond; group 2: metal bracket bonded with F-21; group 3: ceramic bracket (Transcend 2000) bonded with Transbond; and group 4: ceramic bracket bonded with F-21. The brackets were bonded to the etched enamel surfaces according to manufacturer's instructions. All specimens were stored in distilled water for 24 hours and then thermocycled for 300 cycles between 5 degrees C and 55 degrees C. The specimens were mounted in dental stone and placed in the Instron at a crosshead speed of 0.5 mm/min with a knife-edged blade. Immediately after debonding, the enamel surface and bracket-enamel interface were evaluated visually and with a stereomicroscope. Representative samples were then examined with the scanning electron microscope. The analysis of variance and Student-Newman-Keuls tests were performed. The results in megapascals were Group 1: 19,6 (+/- 9,6); group 2: 14,3 (+/- 4,6); group 3: 28,8 (+/- 12,6); and group 4: 18,5 (+/- 7,5). Group 3 was statistically significantly different (P < 0.008) from all other groups. Groups 1, 2, and 4 were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Bicuspid↗
PubMed1994

The effect of etching time with Gluma 2000 conditioning solution on shear bond strength of a composite resin and on micromorphology of the enamel.

The purpose of this study was to assess the effect of etching time with Gluma 2000 conditioning agent on, first, the shear bond strength of composite resin to tooth enamel and, secondly, the micromorphology of the enamel. In the first part of the study flat enamel surfaces were prepared with 600-grit silicon carbide paper on 40 primary and 40 permanent teeth. Ten specimens of each group were etched for 15, 30, 60 or 120 seconds before applying bonding resin and restorative composite resin. After 24 hours' storage in water, the shear bond strength of each specimen was tested. Analysis of variance indicated a significant difference between the eight groups. However, the Student-Newman-Keuls test indicated that the only differences that were significant were the greater bond strengths of the 15-second primary tooth specimens compared with the 15- and 30-second permanent tooth specimens. In most cases the debonded specimens showed cohesive failure in resin close to the coupling interface. In the second part of the study the morphology of the enamel etching patterns in 96 other teeth was studied by scanning electron microscopy. The patterns were similar in primary and permanent teeth, and the longer the etching time the more pronounced was the pattern. The patterns produced in ground enamel were more uniform and predictable than those in pumiced enamel. Examination of bonded resin surfaces after dissolution of the teeth showed complete reproduction of the etched enamel surfaces, indicating excellent flow of the resin into the etched enamel.

Acid Etching, Dental↗
PubMed1994

Shear bond strength of a resin composite to enamel etched with maleic or phosphoric acid.

The purpose of this study was to evaluate the effect of 10 per cent maleic and 37 per cent phosphoric acid on the shear bond strength of Z100 composite resin with Scotchbond Multi-Purpose adhesive to primary and permanent tooth enamel. Four groups of 20 teeth each were established: 1, permanent teeth, 10 per cent maleic acid etched for 15 seconds; 2, permanent teeth, 10 per cent maleic acid etched for 30 seconds; 3, permanent teeth, 37 per cent phosphoric acid etched for 15 seconds; 4, primary teeth, 10 per cent maleic acid etched for 15 seconds. Five teeth from each group were randomly assigned for SEM examination of the etched enamel surface. Scotchbond Multi-Purpose primer and adhesive were applied to the etched enamel surface of the remaining 15 teeth and cured following the manufacturer's instructions. Z100 composite resin was placed in a nylon cylinder and cured for two 40 second intervals. Following thermocycling, the specimens were sheared on an universal testing machine and debonded areas were examined visually with a stereo microscope and with SEM. The mean shear bond strengths in MPa were: 1, 17.00; 2, 14.58; 3, 14.66; 4, 11.18. ANOVA and Student-Newman-Keuls analyses revealed no statistically significant difference among the groups. SEM examination showed the majority of specimens fractured at the adhesive-resin interface.

Acid Etching, Dental↗
PubMed1994

Enhancement of fissure sealant penetration and adaptation: the enameloplasty technique.

The purpose of this study was to evaluate with the scanning electron microscope (SEM) the effects of mechanically enlarging the occlusal fissures with a bur in regards to: (1) fissure micromorphology; (2) sealant penetration into fissures; and (3) micromorphology of the fitting surface of sealants. The technique is described as EST, for Enameloplasty Sealant Technique. The conventional sealant technique is referred to as CST. A total of 30 extracted permanent molars were used and divided into four groups: (1) pumice prophylaxis, no sealant; (2) same as Group 1 but with FluoroShield sealant; (3) EST, no sealant; (4) EST followed by FluoroShield. Subgroups were instituted to evaluate the sealant-enamel interface and the sealant fitting surface. The bur used in this, study was specifically designed for this purpose. Some samples were replicated in epoxy resin and all samples were evaluated with the SEM. The results demonstrated that the EST allowed a deeper sealant penetration and a superior sealant adaptation than the CST. An increased surface area for sealant retention was readily evident in all samples treated with the EST.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1994

Effect of APF gel on light-cured glass ionomer cements: an SEM study.

This SEM study evaluated the micro morphological effect of a 1.23% acidulated phosphate fluoride gel (Oral-B)(APF) on the surface of VariGlass and Vitrebond light-cured glass ionomer cements with or without Ketac Glaze protective surface glazing. Glass ionomer (GI) cylinders (area 6.69 mm) were prepared and divided into six groups of 10 specimens each: Group 1: VariGlass; Group 2: VariGlass + APF gel for 4 minutes; Group 3: VariGlass + Ketac Glaze; Group 4: VariGlass + Ketac Glaze + APF for 4 minutes; Group 5: Vitrebond; Group 6: Vitrebond + APF gel for 4 minutes; Group 7: Vitrebond + Ketac Glaze; Group 8: Vitrebond + Ketac Glaze + APF for 4 minutes. The cements were handled according to manufactures' instructions, except for the groups using the glaze after light-curing the GI. The Ketac Glaze resin was painted with a brush over the GI surface and cured with visible light (Demetron) for 30 seconds. The fluoride gel was left in contact with the surface for 4 minutes, rinsed and dried. All specimens were then mounted on aluminum stubs, coated and evaluated under the SEM. The results indicated that the APF gel etches both GI surfaces considerably and that the unfilled resin glaze protects the GIs from the erosive effects of the APF gel.

Acidulated Phosphate Fluoride↗
PubMed1993

Microleakage of resin-modified glass ionomer cement restorations: an in vitro study.

Microleakage of two resin-modified glass ionomer cement (GIC) restorative materials was compared with that of two conventional GIC restorative materials. Forty-five noncarious extracted human molars were prepared with standardized Class V cavity outlines on the buccal and lingual surfaces. The occlusal margin was in enamel and the gingival margin was in dentin/cementum. All were restored according to the manufacturers' instructions. After thermocycling, 30 teeth were placed in 2% basic fuchsin dye for 24 h, sectioned and viewed with a stereomicroscope to assess microleakage. The other 15 teeth were sectioned, replicated and prepared for marginal gap evaluation using a SEM. Differences in microleakage scores between materials were compared using Kruskal-Wallis and Mann-Whitney U tests. One resin-modified GIC restorative material showed significantly less microleakage against enamel and dentin/cementum compared to the conventional GIC restorative (p < 0.01). Marginal gap formation for both resin-modified GIC restorations was limited to the axial wall of the restorations.

Analysis of Variance↗
PubMed1993

Effect of a resin lining and rebonding on the marginal leakage of amalgam restorations.

This in vitro study compared microleakage in Class V amalgam restorations with three different lining agents and with no lining agent, with and without resin rebonding of the margins. Eight groups of ten molars were divided into four pairs of groups. Class V preparations were cut in the facial surfaces of each molar so that the occlusal margin was in enamel and the gingival margin in dentine. The preparations in one pair of groups received no lining agent; the preparations in the remaining three pairs of groups were lined with one of the following: Copalite, Universal Bond 3 (UB3) Primer and Adhesive, or UB3 Primer only. The enamel walls of the preparations receiving the UB3 Primer and Adhesive were etched prior to applying the lining material. Amalgam was hand condensed into each preparation. In one of each pair of groups, the margins of restorations were treated with 37% phosphoric acid gel, rinsed and dried, and UB3 Adhesive was applied over amalgam and tooth margins and polymerized (rebonded). Specimens were thermocycled, stained and sectioned. Microleakage was graded using a stereomicroscope. Mean microleakage scores for occlusal and gingival margins were calculated and analysed. At enamel margins, non-rebonded Copalite and all rebonded specimens showed less microleakage than the other non-rebonded groups. The group lined with UB3 Primer only and rebonded showed significantly less (P < 0.01) microleakage at enamel margins than all the other groups except the group lined with Copalite and rebonded. At cementum/dentine margins, restorations lined with UB3 Primer and rebonded showed significantly less microleakage than the other groups.

Acid Etching, Dental↗
PubMed1993

Bond strength of resin-reinforced glass ionomer cements after enamel etching.

This study evaluated the shear bond strength of resin-reinforced glass ionomers to enamel etched or unetched. Human, non-carious extracted permanent molars stored in distilled water were used. Flat buccal and lingual enamel surfaces were ground wet on 600-grit silicon carbide paper. The teeth were then distributed at random into six groups of 5 teeth (10 surfaces) each: Group 1: Fuji II LC, no enamel etching; Group 2: Fuji II LC, enamel etched with 10% phosphoric acid for 10 seconds; Group 3: Dyract, no enamel etching; Group 4: Dyract, enamel etched with 10% phosphoric acid for 10 seconds; Group 5: Photac-Fil, no enamel etching; Group 6: Photac-Fil, enamel etched with 10% phosphoric acid for 10 seconds. Cylindrical samples of the glass ionomers were prepared in plastic molds and bonded to the enamel surface according to the manufacturers' instructions. All samples were placed in distilled water for 24 hours, and sheared with an Instron at a crosshead speed of 0.5 mm/minute. The results (in MPa) were: Group 1: 11.29 +/- 4.84; Group 2: 19.64 +/- 5.43; Group 3: 8.26 +/- 3.61; Group 4: 22.04 +/- 5.40; Group 5: 2.05 +/- 3.05; Group 6: 9.12 +/- 6.61. ANOVA and Student-Newman-Keuls procedure revealed that on etched enamel, Fuji II LC and Dyract had a significantly higher bond strength than all the other groups tested (P < 0.0001), but not significantly different between each other. With these two groups, cohesive failure within the material was recorded in all samples while in the unetched samples, all specimens displayed an adhesive failure (glass ionomer-enamel interface). All samples with Photac-Fil, with or without enamel etching had adhesive failures.

Acid Etching, Dental↗