Silicate Cement Restorations Research Articles

Data mining of clinical oral health documents for analysis of the longevity of different restorative materials in Finland

Evidence-based dentistry has shown that different restorative materials have different survival times. Our primary hypothesis is that this should be revealed from normal dental records by the use of data mining technique and a practice-based dentistry approach analysed in a scientifically sound way. Dental records from 1626 patients and altogether 19,892 restorations in three Finnish age cohorts were analysed. Survival curves (Kaplan–Meier) were drawn for each of the restorative materials. Median survival times for amalgam and resin-based composites were more than 15 years in older cohorts. More than 60% of silicate cement restorations were replaced within 5 years, and more than 50% of glass ionomers within 7 years. There was a significant reduction in the longevity of amalgams in the 1980 cohort. Data mining of digital oral heath documents would be a useful tool to analyse survival curves of new restorative materials in a practice-based manner in real-life conditions.

Placement and longevity of tooth-colored restorations in Denmark

A survey has been made of the use of materials and the reasons for placement of 2542 tooth-colored restorations in Denmark. In adults 38% of all the restorations were inserted because of primary caries, and 62% were replacements of failed restorations. In children primary caries was the reason for placing 68% of the restorations in deciduous teeth and 77% of those in permanent teeth. Resin-based materials were the most frequently used tooth-colored restorative, except in the treatment of deciduous teeth, for which glass ionomer cement was used preferentially. Silicate cement was used for less than 2% of the tooth-colored restorations, and the few old silicate cement restorations were most often replaced with resin materials. The reasons for replacement of resin restorations were dependent on dentition, age of the patient, and type of restoration. Secondary caries, fracture of restoration, and loss of fillings were the most frequently recorded failures. The age of the resin restorations replaced ranged from 0 to 19 years, and half of the failed restorations in adults were more than 6 years old. In permanent teeth in children half of the failed resin restorations were replaced within 2 years, whereas half of those in primary teeth were replaced within 1 year.

Restorative treatment pattern and longevity of amalgam restorations in Denmark.

A survey has been made of the reasons for placement and replacement of 6052 amalgam restorations in Denmark. In patients more than 16 years of age 48% of all restorations were made because of primary caries, and 52% were replacements of failed restorations. In primary teeth 64% and in permanent teeth of children 83% of the restorations were made because of primary caries. The reasons for replacement of restorations were dependent on dentition, age of the patient, and type of restoration. Secondary caries was the most frequent reason for replacement of failed restorations in permanent teeth, comprising a third of all replacements. Marginal discrepancies and bulk fracture of fillings were the other two major reasons. In primary teeth fracture and loss of fillings were the two major reasons for replacement of amalgam restorations, whereas secondary caries caused less than a quarter of all restorations to be replaced. The age of the restorations replaced ranged from 0 to 38 years, and half of the restorations replaced in permanent teeth of adults were less than 7 years old. A shorter longevity of failed restorations was noted in primary teeth and permanent teeth of children.

Bacteria and pulpal reactions under silicate cement restorations

Silicate cement was inserted in deep unlined cavities in 70 human teeth; 35 cavities were cleaned with an antibacterial cleanser, and the other 35 cavities in the contralateral teeth were treated with water spray only. In all teeth, invasion of bacteria from the tooth surface was prevented with a surface seal. Histologic examinations after 4 weeks revealed bacterial growth on dentinal walls in 9 of the uncleaned and in 2 cleaned cavities. Only in these 11 teeth was an inflammatory reaction seen in the pulp. Under eight cavities without bacterial growth and with silicate cement placed directly on an exposed pulp, no serious injury and no inflammatory reactions were observed. It was concluded that silicate cement per se does not seriously irritate the pulp. Infection of cavity walls should be avoided, not only by removing grinding debris and antibacterial cleansing, but also by use of a liner to prevent invasion of bacteria from the surface of the tooth.

Penetration of ions from silicate cement restorations into Copalite® - covered cavity walls

This study aimed to asses the effect of silicate cement on Copalite -covered cavity walls in extracted human teeth. Class V cavities were prepared in 24 premolars and filled with silicate cement (Bio-Trey). Four cavities were unlined, the rest of the cavities were lined with 1 or 2 layers of Copalite before insertion of the restorations. After 6 months, 70-100 microns thick longitudinal sections of the teeth were studied by polarized light microscopy, microradiography and electron probe microanalysis. When imbibed in water or quinoline, a subsurface zone of altered birefringence was noticed in nearly all cavity walls. Nearly half of the cavity walls in the experimental groups showed a surface zone of increased radiopacity. In a few instances a subsurface radiolucent zone was present. By electron probe microanalysis F (0,4-3% by weight), Zn (1-4%) and Al (0,2-6%) were measured in the outer 10-60 microns of the cavity walls. The study shows that even with a double layer of Copalite, known to prevent microleakage, a desirable uptake of F and Al from silicate restorations into cavity walls can take place. Copalite does not prevent a phosphoric acid effect on the cavity walls.

Histology of natural secondary caries associated with silicate cement restorations in human teeth

Sections from 70 human permanent teeth with silicate restorations were studied by polarized light microscopy and microradiography. Both frequency and degree of secondary caries appeared low compared with previous findings in respect of amalgam. Both the tooth surface, surrounding the fillings and the cavity walls had acquired a high degree of caries resistance caused by fluorides released from the silicate material. The lesions observed displayed the same pattern as in corresponding previous experimental studies. Increased radiopacity of cavity walls in enamel and dentine relative to normal tissue was relatively frequent, as was retrograde secondary caries.

Correlation of laboratory testing to three-year clinical behavior of silicate cements

A study was carried out to evaluate the correlation between the results of laboratory tests and clinical behavior of silicate cement restorations. Three techniques for placing silicate cement restorations were used. These techniques brought different results when tested for strength and solubility. Changes in surface and marginal integrity of restorations were observed at evaluations made after one and three years of service. At both time intervals, clinically observed changes could not be related to the differences demonstrated by laboratory tests. When considering the specific silicate cement and the specific techniques used in this study, it can be concluded that the differences demonstrated in the laboratory tests of transverse strength and solubility did not predict clinical performance.

Influence of silicate cement restorations on gingiva

Anterior silicate restorations in 210 patients were examined to determine the effect of this material on gingival health. The following clinical observations were made. 1. Thirty-one per cent of the silicate restorations were found to be detective. 2. Silicate cement is a poor material for restoring contact. 3. The material should not be used in cavity preparations extending close to or beneath the free gingiva. 4. Silicate restorations that have undergone erosion in the oral fluids encourage the accretion of bacterial plaque. 5. There is a low incidence of recurrent caries adjacent to silicate cement restorations. 6. The principle of extension for prevention in cavity preparations designed for silicate cements should be re-evaluated in light of the adverse effects this material can have on gingival tissue health.

Quality of Service Provided by Dental Therapists in an Experimental Program at the University of Alabama

Because of the disparity between the need for dental service and the availability of such service, studies have been made at the University of Alabama School of Dentistry on the expanded use of auxiliary personnel. Recent experiments have been conducted over a period of eight months to evaluate the quality of service provided by dental therapists. Six dentists in private practice, two clinical instructors from the department of operative dentistry, and four dental therapists participated in the research. The six clinical procedures investigated included inserting amalgam restorations, finishing amalgam fillings, finishing silicate cement restorations, inserting temporary restorations, and placing matrix bands for amalgam fillings. Evaluations were made by dental practitioners who were unaware whether the dentists or therapists had completed the procedure. Various aspects were evaluated; only a few of the differences were statistically significant. Because of the disparity between the need for dental service and the availability of such service, studies have been made at the University of Alabama School of Dentistry on the expanded use of auxiliary personnel. Recent experiments have been conducted over a period of eight months to evaluate the quality of service provided by dental therapists. Six dentists in private practice, two clinical instructors from the department of operative dentistry, and four dental therapists participated in the research. The six clinical procedures investigated included inserting amalgam restorations, finishing amalgam fillings, finishing silicate cement restorations, inserting temporary restorations, and placing matrix bands for amalgam fillings. Evaluations were made by dental practitioners who were unaware whether the dentists or therapists had completed the procedure. Various aspects were evaluated; only a few of the differences were statistically significant.

The Protection of Silicate Cement Restorations Immediately after Insertion in a Cavity

In this test of different protective layers, petrolatum and varnish or varnish alone was shown to protect silicate cement restorations during the first four to six hours after they are inserted. In this test of different protective layers, petrolatum and varnish or varnish alone was shown to protect silicate cement restorations during the first four to six hours after they are inserted.

A technique for placing facial silicate cement restorations

A technique has been described which offers the dentist the advantage of a high quality silicate restoration with a minimum of finishing. It also frees the dentist to do other things during the setting periods.

Relationship between crazing of acrylic resin fillings and times of finishing and polishing

S ELF-CURING acrylic resin has unique properties as a filling material. Inserted with the brush-on technique, the material is well suited to restore even class V cavity preparations, wedge shaped defects and, by the use of a wire skeleton,lJ more complex preparations. The cumulative result of past investigations has eliminated many disadvantages of the self-cured resins .3-12 Today the clinical results surpass those of silicate cement restorations.13J4

Biologic Considerations in the Selection and Use of Restorative Materials

Restorative materials must satisfy certain physical and chemical requirements before they can be certified for use in patients. They must also satisfy certain biologic requirements. Stated briefly, restorative materials must not be injurious to the living tissues by virtue of their chemical action or marginal leakage, since these may inhibit sclerosis of the dentinal tubules and reparative dentin formation. Since few restorative materials now available can fully satisfy these requirements, properly selected liners and bases should be carefully considered for use under most, if not all, restorations. This is particularly true under silicate cement restorations, under which a calcium hydroxide liner should be used (especially in young teeth), and under amalgam restorations, where a copal resin varnish tends to seal the margins, reduces galvanic action and corrosion and prevents darkening of the underlying dentin by penetration of mercuric ions.

Effects of prednisolone on the thermal sensitivity and pulpal reactions of silicate-restored teeth

A combined clinical and histologic study was carried out to determine the effects of prednisolone on the postoperative thermal sensitivity and pulpal reactions of teeth restored with Class V silicate cement restorations. Blinded and coded determinations of sensitivity to heat and cold, vitality tests, and histologic examinations of serial sections were performed. Based on a comparison between pairs of experimental and control teeth within the same patients, prednisolone was more effective in reducing thermal sensitivity than a placebo, and also resulted in a milder inflammatory reaction in the pulp. The use of prednisolone to reduce postoperative sensitivity should be an adjunct and not a substitute for other means of pulpal protection usually employed in restorative dentistry. The histologic portion of this study was carried out with the technical assistance of Miss Edna M. Preader.

An improved self-curing acrylic restoration and comparison with silicate cement restorations

Many disadvantages of the self-curing acrylic resin restoration have been corrected by an improved technique of cavity preparation, insertion, finishing, and polishing. In a clinical test, acrylic resin surpassed the silicate cement in the significant qualities of discoloration, surface loss, fracture, adaptation, recurrent caries, and pulp injury. Marginal adaptation was superior in the silicate cement restorations. The present advantages of acrylic resin broaden the indications for use. The brush-on method permits insertion of several restorations simultaneously. This study establishes that, although acrylic resin does not fulfill all the requirements of an ideal restorative material, it offers more advantages than the silicate cement.

Pulp reactions to open cavities later restored with silicate cement.

Some early reports have indicated that silicate cements are highly irritating to the pulp.'Yet Barker5 has reported that the reactions that took place under silicate were not sufficiently severe to indicate that death of the pulp might result. Shroff6 has considered that the placement of a properly mixed synthetic porcelain did not produce complete pulp necrosis in the common instance, provided that due care was exercised during cavity preparation and that the cavity was not of exceptional depth. Van Huysen and Boyd7 have concurred. More recently, investgators8 using rats' incisors have reported that the effect of silicate cement on the pulp was always severe. Mitchell,9 using the subcutaneous implantation technique in rats, has reported a moderate to severe soft-tissue reaction to silicate cement. Kozam and Burnett,10 using windows cut in rats' incisors, have suggested that if the acidic components in the cement were to affect the pulp significantly, they would have to be in sufficient excess in a deep cavity as to soften the dentin between the cement and the pulp. Mitchell, Buonocore, and Shazer, using monkeys, have reported a mild or minimal reaction to three silicate cements when the cavity floor was thicker than 400 [t, and that the reaction increased as the floor thickness decreased to 50 pt or pulp exposure. Most research in this field has been done by inserting silicate cement into freshly prepared cavities cut in sound teeth of human beings or animals. In actual practice, carious teeth that may have developed dentinal sclerosis and secondary dentin are usually restored, and it is assumed by most that this protects the pulp from the irritating effect of the restorative material. A study by Weider, Schour, and Mohammed'2 has indicated that cavity depth was the most significant factor in determining the amount of secondary dentin formed in rat molars. Less significant were the different filling materials or exposure to the oral fluids. Zander and Pejkol3 had earlier suggested a 3-month interval be allowed prior to placing silicate cement in order to permit irregular dentin formation for pulp protection. It was the purpose of this study to induce and study the development, amount, and morphology of secondary dentin formed beneath deep cavities in deciduous and permanent teeth prepared and left unrestored for 3 months, also to study the modifying effect of the accumulated secondary dentin on pulp irritation due to silicate cement restorations after 1and 2-week periods. As controls, and to evaluate earlier studies in

Penetration of isotopes through liners and bases under silicate cement restorations

Penetration of isotopes through liners and bases under silicate cement restorations

Temperature and Humidity Control With Silicate Cement Restorations

Temperature and Humidity Control With Silicate Cement Restorations

The Cold Slab in Silicate Cement Restorations

The Cold Slab in Silicate Cement Restorations