The alkalizing properties of calcium hydroxide compounds

Calcium hydroxide compounds are available in various forms, such as in aqueous suspensions or as cements, liners, pastes or filled resins. When such compounds are exposed to water, the calcium hydroxide dissociates and the pH value shifts to the basic. In this study the compounds Pulpdent, Dycal, Hydroxyline, Gangraena Merz and Prisma VLC-Dycal were subjected to analysis, including quantitative measurement of the amount and the chronological course of ion release following exposure to water, qualitative analysis of the alkalizing effects at the dentin surface and examination of antimicrobial properties. The results showed that calcium hydroxide compounds differed greatly. The strongest degree of ion release, combined with definite antimicrobial properties, was found for the aqueous calcium hydroxide suspension (Pulpdent). The cement (Dycal) demonstrated significantly weaker activity. The liner and the paste (Hydroxyline and Gangraena Merz), as well as the calcium hydroxide filled resin (Prisma VLC-Dycal), were largely lacking in both ion release and antimicrobial properties under the experimental conditions.     

The alkalizing properties of calcium hydroxide compounds

Abstract Calcium hydroxide compounds are available in various forms, such as in aqueous suspensions or as cements, liners, pastes or filled resins. When such compounds are exposed to water, the calcium hydroxide dissociates and the pH value shifts to the basic. In this study the compounds Pulpdent®, Dycal®, Hydroxyline®, Gangraena Merz® and Prisma VLC-Dycal® were subjected to analysis, including quantitative measurement of the amount and the chronological course of ion release following exposure to water, qualitative analysis of the alkalizing effects at the dentin surface and examination of antimicrobial properties. The results showed that calcium hydroxide compounds differed greatly. The strongest degree of ion release, combined with definite antimicrobial properties, was found for the aqueous calcium hydroxide suspension (Pulpdent). The cement (Dycal) demonstrated significantly weaker activity. The liner and the paste (Hydroxyline and Gangraena Merz), as well as the calcium hydroxide filled resin (Prisma VLC-Dycal), were largely lacking in both ion release and antimicrobial properties under the experimental conditions.     

Compatibility of a composite resin with pulp insulating materials. A scanning electron microscope study

A scanning electron microscope investigation of the interface between Adaptic and pulp insulating materials was conducted. The surface roughness, as caused by insulated materials, was observed to decrease in the sequence ZOE, Dycal, ZPC, and Copalite. Uncured Adaptic dissolved a cavity varnish. The clinical significance of these observations has been discussed.     

The interaction between lining materials and composite resin restorative materials

The effects of four lining materials, Dycal, Procal, Cavitec and Poly F cement on Adaptic and Concise have been investigated in vitro. The parameters studied were surface roughness, hardness and colour both with and without an intermediate (or bonding) resin being present between the restorative material and the liner. The effects of the four liners on the composites varied both between the lining materials themselves and with the composite resin. Two materials, Procal and Dycal, had little interaction with the composites, provided an intermediate resin was used with the latter. Cavitec appeared to have an adverse reaction with the composites and Poly F, whilst having no effect on the colour of the composites, did increase surface roughness. The adverse effects of linig materials were ascribed to minor constituents, particularly methyl salicylate, present in the formulation.     

Physical properties of calcium hydroxide and glass-ionomer base and lining materials

Compressive, diametral tensile and flexural strengths, moduli of elasticity, pH, and acid solubility values were compared for six calcium hydroxide cements, seven glass-ionomer cements, and one calcium aluminate cement. Results indicated that the glass-ionomer materials were generally stronger than the calcium hydroxide liners. Prisma VLC Dycal showed the lowest value for modulus of elasticity and the least acid solubility. The glass-ionomer materials were initially acidic, reaching a final pH between 5.4 and 7.3, whereas the calcium hydroxide and calcium aluminate cements were strongly alkaline at all time intervals.     

A clinical and histological evaluation of conservative pulpal therapy in human teeth.

Three intermediary base materials, a zinc oxide-eugenol (Cavitec) and two calcium hydroxide liners (Life and Dycal), were selected at random for use as a base beneath amalgam or composite restorations on humans following complete caries removal. Life and Dycal, selected at random, were also used as direct and indirect pulp capping agents as clinically indicated. Clinical evaluations of signs and symptoms were made before treatment and at one-week, six-month, and one-year intervals following treatment. Histological evaluations were performed on three complete caries removal teeth and 18 direct pulp capping teeth six months following treatment. No significant differences in clinical symptomatology resulted between the materials in the complete caries removal group or the indirect and direct pulp capping groups.     

Effect of water spray on lining materials and their adhesion to composite and dentin cavity walls.

The effect of an air-water spray on the adhesion of lining materials to both overlying composite restorations and cavity walls was evaluated. An in vitro study was performed on extracted molar teeth: Two resinous light-cured liners and one calcium hydroxide, chemically activated liner were compared. Teeth were restored with composite materials and subjected to cyclic thermal changes so that microleakage could be evaluated. Results indicated that adaptation between the restorative material and the liner was effective, regardless of whether the oxygen-inhibited layer was removed by being rinsed. A definite gap was detected between the liners tested and the dentin cavity walls.     

In vitro evaluation of pH changes induced by calcium hydroxide liners.

OBJECTIVES: Since the highly alkaline pH of calcium hydroxide is considered by many to be responsible for its biologic activity, the possible variations of pH induced by the different calcium hydroxide liners are accepted as a major concern. The aim of the present study was to determine the pH changes of five different calcium hydroxide liners and variations of pH levels at different time intervals. METHOD AND MATERIALS: The materials tested were Dycal, Life, Calic, Dycal VLC, and Calcident 450. Samples were prepared according to manufacturer instructions and by using plastic molds; five standard samples from each material were prepared. The samples were then placed in separate vials, containing 10 mL deionized water (pH 7.0), and stored at room temperature (200C). The pH measurements were taken 1 hour, 24 hours, 3 days, and 7 days after mixing. The pH variations of each material at the given time intervals were recorded, and the means were calculated. RESULTS: Statistical analysis showed significantly high differences between the mean pH values induced by each material at all time intervals. The highest value for the first-hour measurement was for Dycal VLC, and the highest values for the other time intervals were for Calcident 450. The pH values of the materials exhibited statistically significant differences among all the time intervals. CONCLUSION: All materials changed the pH of deionized water toward alkaline.     

Effect of load-cycling on bond between composite fillings and dentin established by Gluma and various resins

Cylindrical dentin cavities, pretreated with Gluma and various resins, were filled with Silux, P-30, or Concise. Marginal integrity was in most instances obtained when experimental resins containing propionic aldehyde were used. The bond between composite and dentin established in this way was tested by load-cycling. Cervical located cavities in extracted human teeth, approximately one-half of the margins in dentin, were etched and treated as above. Fillings made of Silux, P-30, or Concise exhibited margins without stain upon axial loading in most cases. The frequency of staining increased when Dycal was used as cavity liner, but were absent in all cases when Concise was used as filling material. The content of propionic aldehyde in the intermediary resin layer may reduce the oxygen tension at the interface and thereby increase the rate of the polymerization at this location.     

Direct capping with four different materials in humans: histological analysis of odontoblast activity

Pulp inflammation in restored teeth is mainly due to the presence of bacteria or bacterial products introduced by microleakage around the restoration or to the material toxicity. Recent knowledge has permitted a precise identification of the risks for pulpal irritation associated with adhesive materials and procedures. The purpose of this work was to evaluate the cellular events that occur in direct pulp exposure capped using different materials. Twenty-four vital teeth without caries, scheduled for extraction for orthodontic reasons, were selected. After a control of the hemostasis, each pulp was directly capped with a different material. The samples were randomly divided into four groups of six specimens each: group I: dental-bonding agent (Solist) followed by resin composite (Ecusit); group II: dental adhesive (Prompt) and resin composite (Pertac II); group III: traditional calcium hydroxide (Dycal) plus resin composite (Ecusit); group IV: light-curing calcium hydroxide (Ultrablend Plus) and amalgam (Dentsply). After 15 days the teeth were extracted, immediately fixed in 10% buffered formalin, embedded in resin (7200 Technovit), and prepared for thin ground sections with Precise 1 System. In the specimens of all groups, there were active odontoblasts near the composite resins and no newly formed dentin. Small quantities of inflammatory cells were present. A 1- to 3-microm layer zone of necrosis was present. In conclusion, all materials tested in this study induced similar tissue responses.     

An in vitro evaluation of pH variations in calcium hydroxide liners

The purpose of this present study was to determine the pH changes of five different commercially available calcium hydroxide liners and variations of pH at different time intervals. The following commercially available materials were investigated: Dycal (LD Caulk); Calcimol (Vocco Products); calcium hydroxide powder (Deepti Products); Calcimol LC (Vocco Products); Lime-Lite (Pulpdent Corporation). Five samples were prepared from each liner. The pH measurements were recorded at time intervals of 1 h, 24 h, 3 days and 7 days after mixing of the liner. The pH variations of each material at the given time intervals were recorded and the means were calculated. Comparison of the mean values at all time intervals with the statistical analysis showed significantly high differences (P < 0.001) between pH values induced by each material at all time intervals. Among the water-insoluble products, Dycal had the strongest alkaline effect after 7 days interval. The materials that chemically hardened produced higher pH values than materials that hardened by a visible light source after 7 days.     

Histopathologic study on pulp response to single-bottle and self-etching adhesive systems

This study compared the pulp response to seven adhesive resins (three single-bottle and four self-etching primers) and their companion resin composite systems with a commercial calcium hydroxide material when applied to exposed monkey pulps. The control group was capped with Dycal (DY), while the experimental groups were capped with one of the following adhesive resin systems: AQ Bond (AQ), Single Bond (SB), Imperva Fluorobond (IF), One Step (OS), Prime&Bond NT (PBNT), Perme Bond F (PBF) and One-up Bond F (OBF). Histopathologic evaluation of pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation and bacterial penetration at the 3rd, 30th and 90th post-operative days was done using light microscopy. Data were analyzed using the Kruskal-Wallis test followed by the Least Significant Difference Test to determine differences between the control group and the experimental groups at each observation period. The correlation of inflammatory cell infiltration and bacterial presence was investigated by the Kendall correlation analysis. All tests were performed at a 95% level of confidence. The pulpal responses of groups DY, SB, OS, PBF and OBF were generally characterized by none-to-mild pulp tissue disorganization and inflammatory cell infiltration. Also, initiation of reparative dentin formation was found earlier in Group DY, resulting in more complete dentin bridges at the 30- and 90-day observation periods. Groups AQ, IF and PBNT had significantly more inflammatory cell infiltration and a lower incidence of reparative dentin formation than Group DY. A significant correlation was detected between inflammatory cell infiltration and the presence of bacteria. It is concluded that the pulp response to SB, OS, PBF and OBF is not significantly different from the calcium hydroxide preparation. However, calcium hydroxide capping resulted in a higher incidence and faster rate of reparative dentin formation.     

Marginal leakage in occlusally loaded, etched, class-II composite resin restorations

Microleakage was studied in class-II cavities restored with a calcium hydroxide liner and an adhesive system combined with two different posterior composite resins. The restorations were exposed to repeated loading when immersed in dye solution. The teeth were cut, and microleakage along the cavity walls and into dentin was evaluated by light microscopy. Dye penetration at the interface between the cavity and the restoration was recorded in 61% of the loaded and in 30% of the unloaded teeth. The difference between loaded and unloaded was greater for the teeth lined with Life than with Gluma dentin bonding.     

Reactionary dentinogenesis after applying restorative materials and bioactive dentin matrix molecules as liners in deep cavities prepared in nonhuman primate teeth

OBJECTIVE: The aim of this in vivo study was to evaluate the response of the pulp-dentin complex following application of resin-modified glass-ionomer cement, calcium hydroxide hard-setting cement and EDTA-soluble preparation of dentine matrix proteins (ESDP) in deep cavities prepared in non-human primate teeth. METHODS: Eighteen deep Class V buccal cavities were prepared in premolars of four capuccin monkeys. In Groups 1 and 2, the cavity floor was lined with ESDP or a resin-modified glass-ionomer cement (Vitrebond - 3M ESPE), respectively. In Group 3 (control), the cavity was lined with a hard setting calcium hydroxide cement (Dycal - Dentsply). The cavities were subsequently filled with amalgam. After 6 months, the animals were sacrificed and the teeth were prepared for microscopic assessment. Six-micron thick serial sections were stained with H/E, Masson's trichrome and Brown & Brenn techniques. RESULTS: No inflammatory pulpal response was observed for all experimental and control Groups. However, the amount of reactionary dentin deposition differed between groups in the rank order ESDP (Group 1) > calcium hydroxide (Group 3) > resin-modified glass-ionomer (Group 2). These differences were statistically significant. CONCLUSIONS: All materials were biocompatible when applied in deep cavities. ESDP stimulated higher deposition of reactionary dentin matrix than Vitrebond and Dycal.     

Effect of the tenure dentin bonding system on leakage of light-activated liners

This study investigated the effect of the Tenure dentin bonding system on the sealing properties of four light-activated liners. Dentinal slot preparations were made in extracted human molars and "restored" with Cavalite, TimeLine, VLC Dycal, and Zionomer liners. Samples were immersed in 0.05 percent crystal violet solution for 2 hours, then embedded in clear casting resin, sectioned, and examined with an optical microscope. Our results indicated that the Tenure dentin bonding system reduced dye penetration around each of the light-activated liners tested. The Tenure/VLC Dycal system provided a more effective seal than the other liners.     

Effect of the Tenure Dentin Bonding System on Leakage of Light-Activated Liners

This study investigated the effect of the Tenure dentin bonding system on the sealing properties of four light-activated liners. Dentinal slot preparations were made in extracted human molars and "restored" with Cavalite, TimeLine, VLC Dycal, and Zionomer liners. Samples were immersed in 0.05 percent crystal violet solution for 2 hours, then embedded in clear casting resin, sectioned, and examined with an optical microscope. Our results indicated that the Tenure dentin bonding system reduced dye penetration around each of the light-activated liners tested. The Tenure/VLC Dycal system provided a more effective seal than the other liners.     

Protective effect of different lining materials placed under composite resin restorations in monkeys

abstract — The protective qualities of the cavity lining materials Tubulitec®, Dycal®, Dycal+Tubulitec and De Trey® phosphate cement were tested beneath the composite resin Addent Concise® in 153 monkey teeth. Insufficient pulpal protection was obtained from restorations lined with the phosphate cement, while the three other lining procedures gave good protection.     

Effect of load-cycling on bond between composite fillings and dentin established by Gluma and various resins

Abstract – Cylindrical dentin cavities, pretreated with Gluma and various resins, were filled with Silux, P-30, or Concise. Marginal integrity was in most instances obtained when experimental resins containing propionic aldehyde were used. The bond between composite and dentin established in this way was tested by load-cycling. Cervical located cavities in extracted human teeth, approximately one-half of the margins in dentin, were etched and treated as above. Fillings made of Silux, P-30, or Concise exhibited margins without stain upon axial loading in most cases. The frequency of staining increased when Dycal was used as cavity liner, but were absent in all cases when Concise was used as filling material. The content of propionic aldehyde in the intermediary resin layer may reduce the oxygen tension at the interface and thereby increase the rate of the polymerization at this location.     

The response of four calcium hydroxides on monkey pulps

Abstract Dentinal bridge formation and pulpal responses of four calcium hydroxide materials, pulp capping medicaments, MFC®, Experimental MFC-12, Dycal® and Pulpdent®, were evaluated in primary and permanent monkey teeth. A total of 60 primary and 60 permanent teeth were used with each material placed in a Class V cavity exposure in Rhesus monkey teeth. The materials were placed on the exposed pulp tissue and were histologically evaluated at 3 days, 5 weeks and 8 weeks. After perfusion the teeth were processed using routine histological procedures. The 3-day pulpal responses in both primary and permanent teeth were moderate, characterized by disruption of the pulpal tissue directly beneath the exposure site and a zone of acute inflammation and hemorrhage in the underlying pulp. The 5-week response showed histological differences between the four medicaments, with Dycal producing the least amount of pulpal irritation with reparative dentin bridges occurring in 50% of the permanent teeth. Experimental MFC-12 stimulated one reparative dentin bridge, while Pulpdent and MFC showed no evidence of bridge formation. Pulpal responses to Dycal were moderate and moderate to severe for the other calcium hydroxide compounds. No reparative dentin bridges were seen in the primary teeth at 5 weeks with any of the materials, and the pulpal responses were of a moderate degree at that time. Eight-week responses were similar to the 5-week responses. Dycal provoked a slight to moderate pulpal response with 50% success at bridging. Experimental MFC-12 initiated pulpal responses in the moderate to severe range with some bridging evident. Pulpdent incited moderate to severe histological responses with three teeth demonstrating bridge formation, and MFC provoked severe pulpal responses with no bridging. Primary teeth showed some bridging for all compounds except those treated with MFC, in which no evidence of bridging occurred, and moderate to severe pulpal responses were present.     

MTA用于犬牙直接盖髓术的组织学观察

目的 通过组织学观察，比较MTA（Mineral Trioxide Aggregate)和氢氧化钙制剂(Dycal)在直接盖髓时对牙髓的影响。方法 3条健康杂种犬尖牙12颗，随机分为2组：MTA，Dycal。用裂钻在尖牙唇侧颈部穿髓后以MTA和Dycal盖髓，GIC修复牙体缺损。4个月后将犬处死取下尖牙，常规制作组织切片，观察牙髓炎症反应和牙本质桥形成情况。结果 MTA盖髓的实验组中，5／6无炎症或仅有轻度炎症反应，该组所有标本均有牙本质桥形成。Dycal盖髓的对照组牙髓均有轻度或中度的炎症反应，只有2例出现了牙本质桥。结论 MTA具有良好的生物相容性，适用于直接盖髓术，有望替代现有的盖髓材料。