Biomedical subjects

M A Latta

Publications and source records attributed to M A Latta.

At least 19 recordsLinked to original sources

PubMed2001

Localized wear of compomer restorative materials.

PURPOSE: To determine and compare the localized wear of six compomer restorative materials. MATERIALS AND METHODS: Ten specimens of Dyract, Dyract AP, F2000, Compoglass F, Elan and Hytac were prepared in a custom fixture and polished. A pretest surface profile was generated using an MTS 3-D surface profilometer and the specimens were subjected to 400,000 cycles in a Leinfelder wear machine equipped with a conical stylus tip to simulate localized wear. A post-test profile was generated and the before and after profiles were fitted and analyzed using AnSur 3-D software. The total volume loss and depth of the wear facet on each specimen was calculated and statistical analysis was accomplished (ANOVA and Tukey's test). RESULTS: Volume loss (mm3) was as follows: F2000, 0.027 +/- 0.002; Hytac, 0.007 +/- 0.023; Elan, 0.054 +/- 0.013; Compoglass F, 0.135 +/- 0.006; Dyract AP, 0.135 +/- 0.023; Dyract, 0.185 +/- 0.032. Maximum depth of the wear facets (microm) was as follows: F2000, 112.2 +/- 10.2; Hytac, 132.8 +/- 9.3; Elan, 144.3 +/- 23. 1; Compoglass F, 168.3 +/- 13.0; Dyract AP, 194.0 +/- 19.7; Dyract, 220.6 +/- 15.8. There was not a difference (P > 0.05) in volumetric loss between F2000 and Hytac or between Hytac and Elan. The volume loss and maximum depth of the wear facets of F2000, Hytac and Elan was significantly less (P< 0.05) than Compoglass F, Dyract AP and Dyract The results of this study indicate that there are significant differences in the in vitro wear rates of compomer materials.

Analysis of Variance↗

PubMed2000

Fast-curing lights.

Explore the source record for details and available documents.

Composite Resins↗

PubMed2000

Approaches for intraoral repair of ceramic restorations.

Ceramic-based restorations are an important part of a dentist's armamentarium for durability and esthetics. Because of the brittle nature of ceramic materials, these restorations have the potential to fracture. Repairing ceramic-based restorations can increase the clinical longevity of failed restorations and offer the dentist and patient a cost-effective alternative to replacement. Newer porcelain repair systems show excellent adhesion durability of resin-based composites to the fractured ceramic and exposed metal surfaces. This article reviews the basic principles of ceramic repair and details the use of five intraoral porcelain repair systems.

Ceramics↗

PubMed1998

Dental adhesives in contemporary restorative dentistry.

Significant progress has been made in the area of adhesives in restorative dentistry. With respect to composite restoratives, bond strengths greater than the targeted 17 MPa are now routinely achieved by modern dentin bonding systems in laboratory tests. Each adhesive system must be handled according to the manufacturer's instructions and with careful attention to the details of application for maximal success. Clinical documentation of the success of the modern systems is limited. This especially true for the multipurpose applications often advocated by the product instructions or clinicians lecturing from personal anecdotal experience. The confirmation of laboratory results with controlled clinical trials often occurs late or not at all. A thorough understanding of the in vivo performance is needed to gain the knowledge necessary to further the technologic advances in this area.

Adhesives↗

PubMed1996

Bond strength of an adhesive polymerized under nitrogen.

PURPOSE: To evaluate the use of nitrogen, in conjunction with visible light polymerization, for improving composite-to-dentin bond strengths. MATERIALS AND METHODS: Composite cylinders were bonded to dentin with Scotchbond Multi-Purpose. Immediate (Groups 1-4) and 24-hour (Groups 5-8) strengths were determined for the following two adhesive application and two polymerization techniques: Groups 1 & 5: gentle air thinning of adhesive and polymerization with conventional visible light curing (VLC) unit; Groups 2 and 6: aggressive air thinning of adhesive and conventional VLC; Groups 3 and 7: gentle air thinning of adhesive and polymerization in nitrogen environment with modified VLC unit; and Groups 4 and 8: aggressive air thinning of adhesive and polymerization in nitrogen environment with modified VLC unit. RESULTS: The immediate bond strengths (MPa) were: Group 1: 15.1 +/- 1.8, Group 2: 6.1 +/- 2.1, Group 3: 17.8 +/- 3.1, Group 4: 15.8 +/- 2.0. The 24-hour strengths were: Group 5: 26.7 +/- 4.4, Group 6: 13.5 +/- 7.5, Group 7: 24.1 +/- 5.7, Group 8: 26.4 +/- 4.3. Visible light polymerization of a thinned layer of adhesive resin in a nitrogen environment produced significantly higher immediate and 24-hour bond strengths than when compared to visible light polymerization in ambient air.

Air↗

PubMed1995

4-year clinical study of castable ceramic crowns.

PURPOSE: To evaluate the 4-year clinical performance of castable glass ceramic crowns used to restore teeth in the posterior segments. MATERIALS AND METHODS: 101 castable ceramic (Dicor) full++ crown restorations were placed in 61 molar and 40 premolar teeth using a bonded resin cement. RESULTS: After 4 years of clinical performance, 15 of the original 101 restorations were known to have failed with 13 of those failures affecting molar restorations. All serviceable restorations were rated as excellent for color match, margin adaptation, proximal contact and gingival health. Cavosurface margin discoloration received a 93.5% alfa response. The results of this study show that Dicor crowns meet the esthetic and biological requirements for posterior restorations. The incidence of fracture of molar restorations in this study indicated that when used for restoring molars, careful case selection and caution must be employed.

Adult↗

PubMed1994

Bond strength of a resin cement to a cured composite inlay material.

Although resin cements have been effectively bonded to mineralized tooth structures, bonding to a cured composite material has remained a challenge. This study evaluated the shear bond strength of a resin cement bonded to a cured composite inlay material by use of a variety of composite surface treatments: (1) hydrofluoric acid/60 seconds, (2) ammonium bifluoride/60 seconds, (3) resin adhesive, (4) microabrasion with 50 microns aluminum oxide, and (5) microabrasion with 50 microns aluminum oxide and application of a resin adhesive. The resin cement was also bonded to human enamel that was etched with phosphoric acid. Scanning electron microscopy examinations were completed to evaluate the effects of the composite surface treatments. The results indicated that microabrasion of a cured composite enhances bonding of a resin cement. The bond strength of a resin cement to a composite surface that was air abraded with aluminum oxide, with or without the application of a resin adhesive, was higher than surface treatments with hydrofluoric acid or ammonium bifluoride. Scanning electron microscopy indicated that an irregular surface on the composite was created with aluminum oxide air abrasion.

Acid Etching, Dental↗

PubMed1993

Wear rates of artificial denture teeth opposed by natural dentition.

The wear rate of polymeric or composite-based artificial denture teeth on fixed, removable and implant prostheses is important in the maintenance of cuspal form, masticatory efficiency and occlusal stability. A servo-hydraulic based artificial mouth in which an occlusion was established between artificial denture teeth, and the palatal cusp of a human maxillary third molar was established and used to assess the wear resistance of 5 artificial denture tooth materials. Volumetric wear was determined for Dentsply Trublend SLM, Dentsply IPN, Vita Vitapan, Ivoclar Orthotyp and Ivoclar Orthosit denture teeth. Scanning electron microscopy was also done to assess the textural character of the wear facets of each denture tooth sample. The lowest volume loss was observed for Trublend SLM followed by IPN, Orthotyp, Vitapan and Orthosit. Textural assessment of the materials was consistent with the objective wear data.

Acrylic Resins↗

PubMed1992

Clinical evaluation of castable ceramic veneers.

Laboratory fabricated veneering of discolored or malformed anterior teeth is becoming a widely used technique. Etched Dicor and Dicor Plus ceramic veneers cemented with Dicor Light Activated Cement with Fluoride is one technique available to the practitioner. The purpose of this study was to evaluate the clinical effectiveness of castable ceramic veneers and the cementation system. Forty-three Dicor and 18 Dicor Plus veneers were placed in 12 patients. An intraenamel preparation was completed with a bullet-nosed diamond bur in an ultra-speed handpiece with air-water spray, and a polyvinylsiloxane impression was made. All veneers were fabricated on dies by the same laboratory technician and placed by one practitioner. The restorations were examined by two evaluators at baseline, 3 months, and 1 year, using modified Ryge criteria.

Ceramics↗

PubMed1992

Scanning electronic microscopic analysis of the local effects of a periodontal scaling gel on selected surfaces.

A laboratory study was conducted to evaluate the effects of a periodontal scaling gel on mineralized tooth surfaces and selected dental restorative materials. SofScale Scaling Gel (Ash/Dentsply) was applied on enamel and dentin surfaces of freshly extracted human teeth. These surfaces were evaluated before and after a gel treatment. The gel was also applied to glass ceramic, amalgam, hybrid composite, feldspathic porcelain, glass ionomer, gold alloy, silver palladium alloy, and non-precious alloy. The contact times with these materials and substances ranged from two minutes to sixteen hours. Scanning electron microscopy (SEM) was employed to evaluate differences between treated and control surfaces. Intact enamel and dentin surfaces appeared cleaner without obvious morphological changes with gel contact times up to twelve minutes. When treated for sixteen hours, the enamel exhibited an etch pattern characteristic of a surface treated for sixty seconds with 37% phosphoric acid. No morphological changes were observed on the surface of the restorative materials evaluated with contact times up to twelve minutes. Scanning electron microscopy indicates that SofScale Scaling Gel does not alter the morphological structure of restorative materials, intact enamel and dentin with gel contact times up to twelve minutes.

Cellulose↗

PubMed1992

A clinical evaluation of the effects of a periodontal scaling gel.

This research evaluated the in vivo effects of a periodontal scaling gel used in routine prophylaxis. Fifteen adult patients with moderate to heavy calculus were selected for full mouth hand scaling and prophylaxis using a split mouth design, employing SofScale Scaling Gel in experimental quadrants. Patients and operators were asked to evaluate differences between control and treated quadrants. The following parameters were evaluated during and after treatment: Gingival effects, tooth sensitivity, ease of calculus removal, and overall patient comfort. In addition pre- and post-treatment tooth surfaces were evaluated with scanning electron microscopy using a replicate technique. No tooth sensitivity or soft tissue irritation was observed in any control or experimental quadrants. Calculus removal was independently judged by operators to be easier in the gel treated quadrants when compared to untreated control quadrants. Scanning electron microscopy revealed cleaner enamel and root surfaces with no obvious morphological changes in mineralized tissues. The results of this study demonstrate the safety of the scaling gel and the increased effectiveness of calculus removal during hand scaling of teeth treated with this gel.

Adult↗

PubMed1989

Comparison of two light cured reline systems.

Two commercially available visible light cured reline materials and curing units were compared by in vitro tests. Flexural strength, impact strength, stain resistance, and blanching were measured. Triad VLC Reline Material used with the Triad II Curing Unit (Triad system) exhibited superior properties when compared to Astron LC used with the Astron XL curing unit (Astron system). When alternate combinations of materials and curing units were tested for strength and stain resistance (measure of completeness of cure), the Astron XL curing unit was unable to completely cure Triad VLC Reline Material.

Dental Stress Analysis↗

PubMedDate not supplied

Shear bond strength of Dicor using resin adhesive systems and light activated cement.

A laboratory study was conducted to determine the shear bond strength to dentin of etched and silane-treated Dicor castable ceramic glass using a resin cement and newer generation adhesive systems. Scanning electron microscopy (SEM) examinations were also completed to evaluate the failure sites. The mean shear bond strength of the control (resin cement only, no adhesive system) was 2.1 +/- 1.2 MPa. The shear bond strength values determined for the adhesive systems and resin cement are as follows: Prisma Universal Bond 2, 18.7 +/- 2.9; XR Primer/XR Bond, 16.9 +/- 6.4; Scotchbond 2, 15.8 +/- 6.2; Tenure Solution, 15.4 +/- 4.5; and Gluma, 14.8 +/- 5.5 MPa. SEM examinations of the debonded specimens attached with Prisma Universal Bond 2 and Tenure Solution showed a complex failure pattern with cohesive failure in the glass ceramic material and adhesive failure between the resin cement and the etched and silane-treated glass surface. The debonding pattern of specimens attached with XR Primer/XR Bond, Scotchbond 2 and Gluma were primarily adhesive between the dentin and resin materials. The results of this study support the use of an adhesive system in conjunction with a resin cement for placement of Dicor castable ceramic restorations.

Ceramics↗

PubMedDate not supplied

Bond strength of composite to enamel and dentin using Prime & Bond 2.1.

A laboratory study was conducted to determine the bond strength of composite to enamel and dentin using a one-component dental adhesive system (Prime & Bond 2.1) with three application regimens ranging from four to seven procedural steps. In addition, the effect of acid conditioning of dentin on bond strength was evaluated. Enamel bond strengths ranged from 29.2 to 29.8 MPa, and dentin bond strengths ranged from 18.6 to 21.3 MPa. Enamel bond strengths were significantly higher (P = 0.000) than dentin values. There was no significant difference (P > 0.05) among the bond strengths in either the enamel or dentin groups using the three application regimens. Nor did acid conditioning of dentin increase bond strengths (P = 0.683).

Acid Etching, Dental↗

PubMedDate not supplied

Effect of air abrasion and acid etching on sealant retention: an in vitro study.

PURPOSE: This in-vitro study evaluated shear bond strength and analyzed, via scanning electron microscopy, enamel prepared for pit and fissure sealant placement. Various surface pretreatment methods were conducted prior to short-term (72-hour) and long-term (120-day) analysis. METHOD: Six treatment groups of 14 teeth, having 28 bonding surfaces (buccal and lingual) were treated. Cylinders of Delton pit and fissure sealant were placed on the prepared buccal and lingual surfaces and light-cured for 60 seconds. One-half of each group's specimens were stored in distilled water for 72 hours and the other half were stored in water distilled for 120 days followed by thermocycling. All specimens were subjected to shear bond strength analysis as determined on an Instron testing machine. RESULTS: All acid treated groups were equivalent and greater than air abrasion alone after 72 hours of water storage. Scanning electron microscopy of air-abraded and combination treated enamel surfaces revealed a more detailed retentive pattern in the combination treatment than in either treatment alone. CONCLUSION: Based on in-vitro shear bond strength values, air abrasion with 50 micron alumina is an effective pre-etch treatment for sealant placement and in concert with phosphoric acid treatment significantly enhanced the long-term bond of a sealant to enamel. The clinical relevance of this has not been established.

Acid Etching, Dental↗

PubMedDate not supplied

Comparison of composite resin-to-porcelain bond strength with three adhesives.

Three resin-based adhesives were evaluated for suitability for porcelain repair with composite resin, as measured by shear bond strength of attachment. Photo Bond and SE Bond were associated with significantly greater shear bond strengths than their respective controls at both time periods investigated. Single Bond did not have shear bond strengths greater than its control and its values were significantly lower than those obtained with the other resins.

Acid Etching, Dental↗

PubMedDate not supplied

Physical properties of three packable resin-composite restorative materials.

This study evaluated selected physical properties of three packable resin composites (Alert, SureFil and Solitaire) and compared them to two conventional hybrid materials (Prodigy and Z-100). The specific properties investigated were diametral tensile strength, transverse strength, elastic modulus and fracture toughness. Following photopolymerization, specimens for each composite material were stored in deionized water at 37 degrees C for 35 days. A one-way ANOVA and Tukey's post-hoc test were employed for each property to determine whether significant differences occurred with respect to specific restorative materials. All materials had statistically similar diametral tensile strengths. Alert had the highest mean fracture toughness and elastic modulus but had a low mean transverse-strength value. SureFil exhibited good mean physical property values compared to both the conventional and packable materials. Solitaire had low mean fracture toughness, transverse strength and elastic modulus values, which could cause concern regarding use in posterior restorations. The packable resin composites tested had a wide range of mean values for the physical properties investigated. Generally, Alert and SureFil were superior to Solitaire and comparable to the hybrid materials Prodigy and Z-100, but clear discrimination among performance of these materials requires clinical testing.

Analysis of Variance↗

PubMedDate not supplied

Laboratory evaluation of a metal-priming agent for adhesive bonding.

OBJECTIVE: The purpose of this laboratory study was to determine the bond strength of a base metal alloy to a high-noble alloy and amalgam when a new chemical adhesion promoter was used in conjunction with a resin cement. METHOD AND MATERIALS: Specimens of high-noble alloy and amalgam were prepared in epoxy-filled rings. Base metal cylinders were cast. The ends of the cylinders and the metal bonding substrates were wet ground and air abraded with aluminum oxide. The base metal cylinders were cemented with Panavia 21 resin cement after application of 1 of the following to the high-noble and amalgam metal surfaces: (1) Alloy Primer, (2) ED Primer, (3) Alloy Primer and ED Primer, or (4) tin plating. Bond values were determined after 24 hours' storage and after 3 months' storage and thermocycling. RESULTS: At both 24 hours and 3 months, tin plating yielded the highest bond strengths to a high-noble alloy, but the value for the Alloy Primer groups was not significantly lower. There was no statistically significant difference between the 24-hour and 3-month values within the 4 treatment regimens. CONCLUSION: Treatment of amalgam or high-noble alloy with either tin plating or Alloy Primer before bonding with Panavia 21 resin cement yielded equivalent bond strengths to a base metal alloy. ED Primer was not an effective metal primer. There was no advantage to combining Alloy Primer and ED Primer.

Adhesives↗