Biomedical subjects

F García-Godoy

Publications and source records attributed to F García-Godoy.

At least 19 recordsLinked to original sources

PubMed2003

Effect of one-year water storage on the surface microhardness of resin-modified versus conventional glass-ionomer cements.

OBJECTIVES: Conventional and resin-modified glass-ionomer cements (GIC, RM-GIC) are available for clinical use as restorative materials or as liners and bases. This study was conducted to compare the effect of a 12-month storage period in water on the surface microhardness, measured in Vickers units (VH), between a GIC and a RM-GIC group and to determine if the addition of resins improved the GIC microhardness. METHOD: VH microhardness was assessed in three GIC: Ketac-Fil, Ketac-Molar and Ketac-Silver (KF, KM, KS) and three RM-GIC: Photac-Fil, Fuji II LC and Vitremer (PF, FU, VI) stored in distilled water at 37 degrees C for 12 months. Measurements were taken at 1, 7, 15, 30, 90, 180 and 365 days. The statistical evaluation was done by means of one-way analysis of variance (ANOVA) and Tukey's multiple comparison tests. RESULTS: There are significant VH differences among the materials studied and within each material over storage time. GICs, except for KS, showed a higher VH throughout the study period. Among the RM-GIC, VI showed a significantly higher VH at 12 months than at 1 day. The VH of PF diminished in the final stage of the study, whereas that of FU stabilized. SIGNIFICANCE: The results suggest that the addition of resins to the GIC did not appear to improve the surface microhardness of these materials. Furthermore, the surface microhardness of both the conventional and resin-modified glass-ionomers suffered variations over time. However, these materials should not be deemed inadequate for use in clinical applications. Probably, conventional and resin-modified GICs placed in the oral environment would not be affected to the same extent as in in vitro tests.

Analysis of Variance↗

PubMed2002

A nanoleakage perspective on bonding to oxidized dentin.

The mechanism responsible for sodium-hypochlorite-induced reduction in dentin bond strength and its reversal with reducing agents is unknown. This study examined the relationship between nanoleakage and reversal of compromised bonding to oxidized dentin. Acid-etched dentin was completely depleted of demineralized collagen matrix when sodium hypochlorite was used. Specimens were bonded with two single-bottle dentin adhesives. They were immersed in ammoniacal silver nitrate for 24 hrs before being processed for transmission electron microscopy. For both adhesives, tensile bond strengths of acid-etched dentin were significantly reduced after sodium hypochlorite treatment, but were reversed when sodium ascorbate was used. After sodium hypochlorite application, reticular nanoleakge patterns in hybrid layers were replaced by vertical, shag-carpet-like patterns along the demineralization front. This type of nanoleakage was completely eliminated after sodium ascorbate treatment with the materials tested. Residual sodium hypochlorite within the porosities of mineralized dentin may result in incomplete resin polymerization, and hence compromised bond strength.

Acid Etching, Dental↗

PubMed2001

The safety and efficacy of a children's power toothbrush and a manual toothbrush in 6-11 year-olds.

PURPOSE: To evaluate and compare the oral hard and soft tissue safety and the plaque-removing efficacy of a children's power toothbrush (Braun Oral-B Kids' Power Toothbrush-D10) and a manual toothbrush in children from a general population. MATERIALS AND METHODS: Seventy children aged 6-11 yrs were enrolled into a single-blind, randomized, parallel-design study. At baseline, oral hard and soft tissues were evaluated and plaque was assessed on buccal and lingual surfaces of all fully erupted permanent and primary teeth using the Turesky Modification of the Quigley-Hein Plaque Index. Eligible subjects were randomized to use either a Braun Oral-B children's power toothbrush (D10) or a manual toothbrush for the duration of the study. Subjects were instructed to brush their teeth at home twice daily for 1 min each day for the 30-day study period. At baseline and after 15 and 30 days, plaque was assessed following 12-18 hrs of no oral hygiene. In addition, at each visit single-use plaque removal was evaluated after subjects had brushed their teeth for 1 min under supervision. Oral hard and soft tissues were assessed for safety before and after the supervised 1-min brushing at each visit. RESULTS: There were no pre-brushing oral hard and soft tissue abnormalities or post-brushing changes in oral tissues in either group. There were statistically significant reductions in mean plaque index for the whole mouth (P< 0.006), buccal surfaces (P < 0.0001) and anterior teeth (P< 0.008) from day 0 to day 30 in the D10 group, but not in the manual group. Greater mean changes in whole mouth plaque reduction were seen for the D10 group as compared to the manual group at days 15 and 30 (P< 0.05). Results from the single-use supervised brushing at each visit revealed that reductions in mean whole mouth plaque were statistically significant in both groups at each visit (P< 0.0001). There was statistically significantly greater plaque removal after a single brushing at day 0 in the D10 group compared with the manual group (P< 0.002), but the difference was not significant at days 15 and 30.

Analysis of Variance↗

PubMed2001

Nanoleakage at the composite-dentin interface: a review.

The term "nanoleakage" was introduced to describe a specific type of leakage within the dentin margins of restorations. Nanoleakage appears as a consequence of the acid etching procedure allowing the penetration of oral and pulpal liquids such as acids into porosities within or adjacent to the hybrid layer. Nanoleakage is independent from microleakage. The amount of penetration depends on the type of bonding agent and on different parameters of the application technique (e.g. etching time, dentin moisture). Nanoleakage is much less extensive than microleakage and has probably no short-term clinical relevance. The long-term stability of the adhesive bond between dentin and restorative material, however, might be adversely affected. Nevertheless, based on the knowledge to date, acid etching prior to dentin bonding should be performed.

Acid Etching, Dental↗

PubMed2001

ER-YAG laser pretreatment effect on in vitro secondary caries formation around composite restorations.

PURPOSE: This in vitro study determined if Er-YAG laser used in instead of acid-etching influenced artificial secondary caries formation in enamel and root surfaces. MATERIALS AND METHODS: Class V cavities were prepared in buccal and lingual surfaces of 10 extracted caries-free molars, with cervical margins in the root surface and occlusal margins in enamel. The specimens were randomly assigned to 2 groups: Group 1: Enamel and dentin etched with 35% phosphoric acid gel (Scotchbond 15s, rinse 10s; n=5 teeth with 2 cavities per specimen, 10 occlusal and 10 root surface margins at caries risk). Group 2: Enamel and dentin surfaces conditioned using a pulsed Er-YAG laser (KAVO) with 2.94 microm wavelength, 250 micros pulse duration, 300 mJ for enamel and 250 mJ for root surface pulse energy, 2 Hz repetition rate, and water cooling (n=5 teeth with 2 cavities per specimen, 10 occlusal and 10 root surface margins at caries risk). The cavity preparations were restored with a wet-bonding technique (Scotchbond 1 adhesive system) and a hybrid resin, light-cured composite (Z100, A3 shade), according to the manufacturer's instructions. Acid-resistant varnish was applied leaving the restoration and a 1 mm rim of adjacent surface enamel and root surface exposed. The specimens were thermocycled (5-50 degrees C, 500 cycles, dwell time 30s). Following artificial caries formation (2.2 mM calcium, 2.2 mM phosphate, 50 mM acetic acid, 5.0 mg/L fluoride, pH 4.25, 10 days), longitudinal sections (3/tooth, 30 occlusal and cervical caries risk sites per group) were taken for polarized light microscopic examination (water imbibition). Primary surface lesion depth and wall lesion frequency was determined and compared between groups (Student's t-test). RESULTS: Er-YAG laser irradiation resulted in a 56% reduction in primary enamel surface lesion depth (116 microm mean depth) when compared with the acid-etched group (263 microm mean depth), and a 39% decrease in root surface lesion depth (194 microm mean depth) compared with that (316 microm mean depth) for acid-etching pretreatment (P< 0.05). Wall lesion frequency was similar (P>0.05) between treatment groups.

Acetates↗

PubMed2000

Effect of a sodium hypochlorite gel on dentin bonding.

UNLABELLED: It has been suggested that the hybrid layer (HL) does not play any important role in the mechanism of adhesion to dentin. To substantiate this hypothetical insignificance of the HL, sodium hypochlorite (NaOCl) has been used to remove collagen from etched dentin prior to bonding. OBJECTIVES: The present study was conducted to determine the effect of a commercial 10% NaOCl gel on the dentin shear bond strengths and HL ultra-morphology of two simplified dentin adhesives. The null hypothesis tested was that treatment of etched dentin collagen with NaOCl would not compromise dentin bonding. METHODS: The labial surface of eighty bovine incisors was polished to expose middle dentin. The specimens were randomly assigned to two total-etch adhesive systems (N = 40): Prime&Bond NT (Dentsply Caulk); and Single Bond (3M Dental Products Division). After rinsing off the etchant, one drop of 10% NaOCl (AD Gel, Kuraray Ltd.) was applied to the etched dentin surface and left for 0 (control), 15, 30, or 60 s. The gel was rinsed off with water and the dentin surface kept visibly moist prior to the application of the adhesive as per manufacturer's instructions. The respective composite resin was subsequently applied and light-cured. After 24 h in water at 37 degrees C, the specimens were thermocycled for 500 cycles in baths kept at 5 and 55 degrees C and the shear bond strengths measured. The data were analyzed with two-way ANOVA. For TEM, sixteen dentin disks were taken from middle dentin of extracted human third molars, assigned to the eight treatment sequences, and observed. RESULTS: The increase in the NaOCl application time resulted in a progressive decrease in shear bond strengths for both dentin adhesives. For Single Bond, the application of AD Gel for 60 s resulted in a reduction of bond strengths to 38% of that obtained for the control. For Prime&Bond NT, the mean bond strength obtained when AD Gel was applied for 60 s was 31% of that obtained for the control. The application of AD Gel resulted in distinct morphology for each one of the two adhesives tested. For Single Bond, the general morphology of the collagen network was maintained, regardless of the deproteinization time. The interfibrillar space within the collagen network increased with increasing deproteinization times. For Prime&Bond NT, the general appearance of the HL was maintained for deproteinization times of 15 and 30 s. When the NaOCl gel was applied for 60 s, the morphological appearance of the HL lost its fibrillar arrangement. While remnants of the collagen fibers were observed in one of the dentin disks, the other specimen showed an amorphous structure without any discernible HL morphological features. SIGNIFICANCE: The integrity of the collagen fibrils left exposed upon acid-etching plays a major role in the mechanism of adhesion of the specific adhesive systems tested in this study. The intermingling of the adhesive monomers with the filigree of collagen fibers or HL should still be considered the paramount dentin bonding mechanism.

Acid Etching, Dental↗

PubMed2000

Microleakage and SEM interfacial micromorphology of amalgam restorations using three adhesive systems.

OBJECTIVE: This study evaluated the microleakage and interfacial micromorphology of Class V cervical amalgam restorations lined with OptiBond, AElitebond, or Panavia 21. METHODS: Unlined amalgams served as control. Cavities were treated with each dentin bonding system according to the manufacturers' instructions and restored with Tytin non-gamma 2 spherical amalgam. After one week of storage in tap water at 37 degrees C, the specimens were thermocycled (1000 cycles, 6-60 degrees C, 30s dwell time). Microleakage was assessed by means of basic fuchsin dye penetration and recorded according to an ordinal scale. RESULTS: None of the systems tested in this study completely eliminated microleakage. Kruskal-Wallis one-way ANOVA and Mann-Whitney U test found that on the occlusal wall, Panavia 21 and the control group had the least leakage (P<0.05). No statistically significant differences were found at dentin margins (P>0.05). Wilcoxon matched pairs signed rank test found that Panavia 21 and the control group had less leakage at the occlusal than at the dentin margins (P<0.05); when AElitebond and OptiBond groups were evaluated, microleakage at the enamel and at the dentin margins was similar for each group. With the adhesive systems, perhaps the hydrophilic bonding agents incorporated the dye during specimen immersion and/or sectioning. CONCLUSIONS: The use of adhesives may not be as worthy as resin cements for sealing and bonding amalgam restorations to enamel and dentin.

Adhesives↗

PubMed2000

The clinical performance of laboratory-fabricated crowns placed on first permanent molars with developmental defects.

BACKGROUND: Young permanent molars with developmental enamel defects commonly are treated with stainless steel crowns. However, allergic reactions to nickel and chromium have been reported by some patients. The literature contains no evaluations of alternative treatments. METHODS: In a retrospective study, the authors evaluated the clinical performance of cast gold crowns and tooth-colored composite or ceramic crowns placed on first permanent molars with developmental defects in children 6 to 8 years of age. A total of 41 molars were prepared. After crown preparation, an impression was made, and crowns of cast gold, Artglass (J.F. Jelenko & Co.) composite or Empress (Ivoclar) leucite-containing ceramic were fabricated and clinically evaluated every six months for a period ranging from two to five years postoperatively (mean three years). RESULTS: After two to five years, all crowns were fully retained. The marginal adaptation of 39 of the 41 crowns was rated excellent, and the marginal adaptation of the remaining two crowns (both gold) received acceptable ratings. In two cast gold crowns, the margins were subgingival at cementation; the remaining 39 crowns had supragingival margins at the time of luting. By the end of the second year, all margins were supragingival. All teeth were vital and asymptomatic at all evaluation points. No secondary caries was recorded. Neither gingival inflammation nor loss of vertical dimension was recorded in any case. All crowns were well-accepted by the patients and their parents. CONCLUSIONS: Laboratory-fabricated crowns can be used for the treatment of young permanent molars with developmental defects. CLINICAL IMPLICATIONS: Cast gold, composite or ceramic crowns can be used successfully to treat developmental defects of first permanent molars in children.

Child↗

PubMed2000

Infant oral health.

According to the United Nations' Convention on "The Rights of the Child," articles 2 and 24, all children should have the same rights and have right to health and medical service. Early childhood caries is a lifestyle disease with biologic, behavioral, and social determinants. An early screening of all children at around 1 year of age is an excellent opportunity for early detection of risk factors and risk indicators that may increase the possibilities for its prevention. The caries risk evaluation should form the base for appropriate recommendations of preventive measures. The preventive care must be coordinated with an eventual operative care and should be based on education of prospective and new parents as well as professional and home-based measures. The various interventions must be developed further and evaluated in prospective studies in terms of effectiveness and efficiency for this specific age group. This is an urgent task for dental professionals and all societies with the ambition of providing good dental care for all young children.

Child↗

PubMed2000

Principles of diagnosis and treatment of high-caries-risk subjects.

The aim of this article is to highlight the main goals and to describe the clinical impact of the procedures used for the identification of high-caries-risk subjects. The techniques for the correction of caries risk level and their influence on restorative treatment are also described to enable the dental team to offer patients the most appropriate and successful treatment, and to meet an up-to-date and high-quality dental care standard.

Anti-Infective Agents, Local↗

PubMed2000

Resin-based composites and compomers in primary molars.

Resin-based composite resins and polyacid-modified resin-based composites (compomers) have become popular for the restoration of primary anterior and posterior teeth. In some European countries, resin-based composites or glass-ionomers are the materials of choice for primary teeth because of the controversy over dental amalgam and its alleged adverse health effects resulting from the release of mercury, although a clear correlation between amalgam restorations and health has not been determined. Another reason for the worldwide increased use of resin-based composites and glass-ionomers in pediatric dentistry could be attributed to the growing demand from parents to provide esthetic restorations to their children. More conservative preparations can be performed maintaining more tooth structure because of the adhesive properties of the composites and compomers. The most conservative treatment planning and meticulous care in the placement of the resin-based composites and compomers would produce long-term satisfactory results. These restorations should be placed in patients with low-to-moderate caries risk, and after placement the restorations should be monitored carefully to avoid complications mainly produced by recurrent caries and wear.

Adhesives↗

PubMed2000

Treatment of trauma to the primary and young permanent dentitions.

An overview of the various possibilities for trauma to the primary and young permanent dentition has been presented. Appropriate treatment procedures have been described. Advances in dental science have been great, and dental materials have become superior to what they were just a few years ago. The dentist must never forget the variabilities of human responses to any of the treatment techniques, however, and the dentist must never be dogmatic in approach. The dentist should be able to diagnose, interpret, and alter any of the treatment techniques as more scientific evidence is obtained.

Child↗

PubMed2000

Clinical evaluation of fiber-reinforced epoxy resin posts and cast post and cores.

PURPOSE: This retrospective study evaluated treatment outcome of cast post and core and Composipost systems after 4 yrs of clinical service. MATERIALS AND METHODS: 200 patients were included in the study. They were divided in two groups of 100 endodontically treated teeth restored with a post. Group 1: Composipost systems were luted into root canal following the manufacturer's instructions. Group 2: Cast post and cores were cemented into root canal preparations with a traditional technique. The patients were recalled after 6 months, 1, 2 and 4 yrs and clinical and radiographic examinations were completed. Endodontic and prosthodontic results were recorded. RESULTS: Group 1: 95% of the teeth restored with Composiposts showed clinical success; 3% of these samples were excluded for noncompliance and 2% showed endodontic failure. Group 2: Clinical success was found with 84% of teeth restored with cast post and core. 2% of these samples were excluded for noncompliance, 9% showed root fracture, 2% dislodgment of crown and 3% endodontic failure. Statistical evaluation showed significant differences between Groups 1 and 2 (P < 0.001). The results of this retrospective study indicated that the Composipost system was superior to the conventional cast post and core system after 4 yrs of clinical service.

Boron Compounds↗

PubMed2000

Clinical results and new developments of direct posterior restorations.

PURPOSE: To (1) review the literature and analyze the longevity and reasons for failure of direct resin-based composite (RBC), amalgam, and glass-ionomer cement (GIC) restorations in stress-bearing posterior cavities and (2) to assess new material developments and treatment techniques to restore these cavities. MATERIALS AND METHODS: This work reviewed the dental literature predominately of the last decade for longitudinal, controlled clinical studies and retrospective cross-sectional studies. Only studies investigating the clinical performance of restorations in permanent teeth were included. Annual failure rates of direct resin-based composite, amalgam, and GIC restorations were determined and failure reasons were discussed. RESULTS: Annual failure rates in posterior stress-bearing cavities were determined to be: 0-9% for direct RBC restorations, 0-7% for amalgam restorations, and 1.9-14.4% for GIC restorations. The median annual failure rate of longitudinal studies for amalgam was calculated with 1.1%, for RBCs 2.1% and for GICs 7.7%. GIC is significantly worse compared with amalgam and RBC. Main reasons for failure were secondary caries, marginal deficiencies, fracture, and wear. Longitudinal studies showed a strong trend towards a higher longevity compared with cross-sectional investigations.

Composite Resins↗

PubMed2000

Compomer materials and secondary caries formation.

PURPOSE: To evaluate the role of compomers in secondary caries formation in vitro. MATERIALS AND METHODS: 36 human teeth with caries-free enamel (coronal) and root surfaces underwent a fluoride-free prophylaxis. Class V cavities were prepared in buccal and lingual coronal and root surfaces. The teeth were divided into two groups with 3 treatment subdivisions [12 teeth per restorative material (6 with coronal restorations and 6 with root surface restorations)]). The preparations were restored with: (1) filled composite (Filtek Z250 with Single Bond), (2) fluoride-releasing compomer [Hytac with Prompt L-Pop (fluoride-releasing water-based adhesive)]; or (3) fluoride-releasing compomer [Dyract AP with Prime & Bond NT (fluoride-releasing acetone-based adhesive)]. 24 cavities (6 teeth with 2 cavities/tooth) were available with each treatment. The teeth were thermocycled (500 cycles at 5-50 degrees C) in synthetic saliva prior to artificial caries formation. After lesion formation, 5 longitudinal sections were taken from each specimen for polarized light evaluation. Mean surface lesion depths and wall lesion frequencies were determined. RESULTS: The Filtek Z250 group had significantly (P < 0.05, ANOVA, DMR) greater mean body of the lesion depths in coronal (205 microm) and root surfaces (221 microm) than either the Hytac (119 microm coronal and 161 microm root surfaces) or the Dyract AP (127 microm coronal and 149 microm root surfaces) groups. Likewise, wall lesion frequency was significantly higher (P < 0.05, ANOVA, DMR) for the Filtek Z250 group (41% coronal and 37% root surfaces) compared with either the Hytac (31% coronal and 25% root surfaces) or Dyract AP (26% coronal and 21% root surfaces) groups. No differences in outer body of the lesion depths or wall lesion frequencies were found between Hytac and Dyract AP for coronal and root surface restorations (P > 0.05, ANOVA, DMR).

Analysis of Variance↗

PubMed2000

Dentin bond strength of packable composites using one-bottle adhesives.

PURPOSE: To evaluate the shear bond strength to dentin of packable composites using their respective one-bottle adhesives. MATERIALS AND METHODS: Human, noncarious extracted permanent molars stored in distilled water were used. Flat buccal and lingual dentin surfaces were ground wet on 600-grit silicon carbide paper. The teeth were then distributed at random into four groups of 8 teeth (16 surfaces) each: Group 1: Gluma Comfort Bond/Solitaire II; Group 2: Bond 1/Alert; Group 3: Prime & Bond NT/Surefil; Group 4: OptiBond Solo/Prodigy Condensable. Group 5: Single Bond/Z250 (control) Cylindrical samples of the materials were prepared in plastic molds and bonded to the dentin surface according to the manufacturers' instructions. All samples were placed in distilled water for 24 hrs, thermocycled for 500 cycles in distilled water at 6 degrees C and 60 degrees C and sheared with a universal testing machine at a crosshead speed of 0.5 mm/min. RESULTS: In MPa: Group 1: 24.39 +/- 3.54; Group 2: 28.96 +/- 4.62; Group 3: 30.77 +/- 4.71; Group 4: 30.82 +/- 3.29; Group 5: 24.93 +/- 5.14. ANOVA revealed that Groups 1 and 2 were statistically significantly different from the other groups; there was no statistically significant difference between Groups 2, 3 and 4.

Adhesives↗

PubMed1999

Microleakage of Class V resin-modified glass ionomer and compomer restorations.

STATEMENT OF PROBLEM: Resin-modified glass ionomers and polyacid-modified resin composites (compomers) have been introduced to provide esthetic restorations. However, there is concern about the marginal sealing ability of these materials, especially at the dentin (cementum) aspects of restorations. PURPOSE: This in vitro study evaluated the microleakage of Class V restorations made with resin-modified glass ionomers or a compomer. MATERIAL AND METHODS: Thirty noncarious human molar teeth were used. Standardized kidney-shaped Class V cavity preparations were placed in the buccal and lingual surfaces at the cementoenamel junction. Teeth were randomly assigned to 3 experimental groups of 10 teeth each and restored as follows: group 1, Fuji II LC; group 2, Vitremer; and group 3, Dyract. In all cases, the manufacturers' instructions were strictly followed. All materials were placed in a single increment. Unfinished restorations were immediately coated with the respective manufacturers' sealer or varnish and this was either light cured for 20 seconds or allowed to air-dry. After 24 hours, teeth were finished to contour and to the cavosurface margins, coated with nail varnish except for 1 mm around the restoration margin, thermocycled (1000x, 5-55 degrees C) and placed in a solution of 2% basic fuchsin dye for 24 hours at room temperature. The staining along the tooth restoration interface was recorded. RESULTS: Kruskal-Wallis 1-way analysis of variance revealed significant differences among all restorative materials for the overall, occlusal, and gingival scores (P =.03, P =.01, P =.01, respectively). Occlusal and gingival scores for each matched pair of restorative materials using the Wilcoxon test showed statistically significant differences between Fuji II LC glass ionomer cement and Dyract composite, both for the occlusal (P =.005) and gingival (P =.005) margins and also as an overall evaluation (P =.01), with Fuji II LC showing the least dye penetration. Vitremer revealed dye penetration scores not significantly different from Fuji II LC glass ionomer cement or Dyract composite. CONCLUSION: Resin-modified glass ionomers showed less or similar microleakage than the polyacid-modified composite resin tested.

Analysis of Variance↗

PubMed1999

Esthetic restoration of primary incisors.

A simple and esthetic technique for restoring cariously involved primary maxillary incisors is described. The technique includes mini-pins, a preformed celluloid crown and resin-based composite.

Child, Preschool↗