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.

Microleakage of three cement bases.

The purpose of this study was to evaluate the ability of a glass-ionomer cement-base material to prevent bacterial penetration along the dentin interface and to compare it with two conventional cement-base materials. A total of 107 Class 5 restorations was placed in Rhesus monkey teeth by means of three test materials [zinc oxide-eugenol (ZOE), copalite varnish + zinc phosphate cement base (V + ZP), and a glass-ionomer lining cement (GI)], with unetched and unbonded resin composite used alone as a control material and as a final restoration over the test base materials. Following disinfection, Class 5 cavities were prepared on the buccal surfaces of the teeth to the inner one-half of dentin. A sterile filter-paper disk was then placed on the axial wall and covered with a Teflon disk. Next, the cavities were based to the dento-enamel junction with one of the test base materials and finally restored with unetched and unbonded resin composite. After five and 16 weeks, the filter-paper disks were retrieved and cultivated for the presence and type of bacteria. The five-week results showed positive growth in two groups: the composite-only controls and the V + ZP group. The 16-week results showed growth in all of the test groups, but only one of nine teeth showed growth in the zinc oxide-eugenol group and one of 16 teeth in the glass-ionomer group. The results of this study indicate that under the conditions tested, a glass-ionomer base was capable of minimizing bacterial penetration along the material-tooth interface.

Healing of primate dental pulps capped with Teflon.

The pulps of Rhesus monkey teeth were exposed and capped with three materials: Teflon, a commercial hard-set calcium hydroxide (Ca(OH)2) material, and Ca(OH)2 plus saline. Experimental test periods were 3, 10, and 21 days, and 5 and 8 weeks. After treatment, the teeth were removed and processed for routine histologic evaluation. Teeth treated with the two Ca(OH)2 materials showed resolution of the inflammatory response and hard tissue formation at the exposure site as early as 10 days postoperatively, with consistent healing at 21 days and longer. Teflon had a similar soft tissue healing pattern but at a slower rate. Hard tissue formation at the exposure site in the teeth treated with Teflon was infrequent at the early time periods and present in only 20% of the teeth treated for 5 and 8 weeks. By evaluating the soft and hard tissue responses of the Ca(OH)2-capped and Teflon-capped teeth it may be possible, in future studies, to identify events unique to odontoblast differentiation during pulpal healing.

An evaluation of a glass ionomer luting agent: bacterial leakage.

This study quantitatively evaluates the bacterial leakage beneath crowns cemented with a glass ionomer cement compared with those cemented with a polycarboxylate cement or a varnish plus zinc phosphate cement. Bacterial samples were taken from beneath full crowns cemented with the test luting agents 3, 10, and 56 days after cementation. Two-way analysis of variance of the resultant data showed a significant increase in bacterial counts for zinc phosphate, a significant decrease for polycarboxylate, and no change for glass ionomer. These findings suggest that bacterial leakage may not be the reason for the reported poor clinical response associated with glass ionomer luting agents.

An evaluation of a glass ionomer luting agent: pulpal histological response.

Pulpal histological response after crown cementation with a glass ionomer luting agent was evaluated and compared with the response to a polycarboxylate cement or a varnish plus zinc phosphate cement. Pulpal histological response was evaluated on teeth that had full crowns cemented with the test luting agents 3, 10, and 56 days after cementation. No statistically significant differences were found in pulpal histological response between the materials tested during all periods. These findings suggest that factors other than pulpal inflammation are contributing to the reported hypersensitivity after cementation associated with glass ionomer luting agents.

Quality assessment of amalgam and inlay restorations on posterior teeth: a retrospective study.

This study was designed to assess and compare the quality of posterior proximo-occlusal amalgam and inlay restorations relative to type of restoration (material, surfaces involved, and cusp protection) and length of service of the restorations. A clinical evaluation system based on operationally defined and clinically important criteria was used. Clinically and statistically significant differences were found between overall ratings for amalgam and inlay restorations and between small (two-surface) amalgam and inlay restorations, as well as between larger (three-surface) amalgam and inlay restorations. In all cases, inlay restorations were of higher quality. A not acceptable rating for marginal integrity was the most frequent reason for not acceptable overall ratings. There was no difference in satisfactory/not acceptable ratings for inlay restorations with or without protected cusps (p = .95).

Pulp capping of dental pulp mechanically exposed to oral microflora: a 1-2 year observation of wound healing in the monkey.

Four adult Rhesus monkeys provided 120 teeth for buccal Class V cavities. Twenty-nine were non-exposed controls and 91 were exposed for 3 intervals. All 120 teeth were capped with a hard set Ca(OH)2 medicament, restored with amalgam, 57 evaluated after 1 year and 63 after 2 years. Of the 91 exposed pulps, 45 showed complete healing, 25 showed pulpal inflammation varying from acute to chronic, 12 showed severe pulpal breakdown and abscess formation and 9 were necrotic. No difference was observed in the healing response between the 3 exposure times. New hard tissue formed at, or subjacent to, the medicament in 77 of 91 exposed pulps with a tunnel defect frequently present, running from the medicament interface to the pulp. This study demonstrates that recurring pulp inflammation observed after 1 & 2 year direct pulp capping, is associated with bacterial contamination.

Capping of the dental pulp mechanically exposed to the oral microflora -- a 5 week observation of wound healing in the monkey.

The healing capacity of mechanically exposed and bacterially contaminated dental pulps was assessed in monkeys after capping with 2 commercial Ca(OH)2 containing compounds. One hundred eighty teeth in 7 monkeys were employed, 45 as untreated controls and 135 as treated exposures. Class V buccal cavity preparations resulting in pulpal exposure were prepared, left open to the oral cavity for 0, 1, 24 h or 7 days and employed as controls, or debrided, capped, restored with amalgam and left undisturbed for 5 weeks as treated exposures. Zero and 1 h untreated exposures presented damage from the mechanical trauma only, whereas 24 h and 7 day pulp wounds exhibited pronounced infiltrations of polymorphonuclear and mononuclear leukocytes. In addition, the 7 day exposures demonstrated several teeth with partial and total necrosis. Treated 0, 1 and 24 h exposures demonstrated wound healing, minimal pulp tissue inflammation, reorganization of soft tissue and formation of new hard tissue at the exposure site in 86 of 99 teeth. Treated 7 day exposures healed less frequently, showing signs of dentin bridging in 15 of 27 teeth. This study indicated that mechanically exposed and orally contaminated dental pulps in monkeys have a high capacity to resolve inflammation and initiate healing with new dentin formation at the exposure site when treated as described.

Histological considerations of direct pulp capping agents.

The results from this study showed a variety of pulpal responses to various calcium hydroxide materials when placed directly on the dental pulp. Two of the materials proved to be more successful at stimulating reparative dentin bridging and healing of the underlying pulp tissue. The remainder of the pulp capping agents were ineffective at healing the pulp and forming a reparative dentin bridge. When teeth were capped with these other agents, the pulp showed necrosis and chronic inflammation.

The response of four calcium hydroxides on monkey pulps.

Dentinal bridge formation and pulpal responses of four calcium hydroxide materials, pulp capping medicaments, MPC, Experimental MPC-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 MPC-12 stimulated one reparative dentin bridge, while Pulpdent and MPC 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 MPC-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 MPC provoked severe pulpal responses with no bridging. Primary teeth showed some bridging for all compounds except those treated with MPC, in which no evidence of bridging occurred, and moderate to severe pulpal responses were present.

The effect of various restorative materials on the microhardness of reparative dentin.

This study showed a statistically significant difference between the microhardness of reparative and primary dentin at both five-and eight-week intervals. Reparative dentin from occlusal trauma is harder than reparative dentin underlying a cavity preparation at the 99% level. No statistical difference was noted in the hardness of reparative dentin underlying different materials, but trends were observed.

Histopathologic and bacterial evaluation of conventional and new copper amalgams.

In vivo pulpal responses in monkeys and in vitro bacterial inhibition studies were completed on new copper amalgams, Sybraloy, Dispersalloy, Tytin and a conventional Spheraloy amalgam. Amalgams were placed in cavities lined with ZOE and in unlined cavities. Silicate and ZOE were used as controls. A total of 165 adult monkey teeth were evaluated at 3 days, 5 and 8 weeks. At 3 days the pulpal responses elicited by the copper amalgams appeared similar to conventional Spheraloy, all showing a slight to moderate response. At 5 weeks the majority of amalgams exhibited a slight pulpar response with a tubular reparative dentin under each restoration. The 8 week pulpal response showed a reduction of the inflammatory response characterized by a tubular reparative dentin with a uniform zone of predentin. Lined ZOE controls exhibited a slight response while silicate showed a moderate response with some persistent chronic inflammation. In vitro bacterial tests revealed that the various amalgams had little to no inhibitory effect on the three serotypes of S. mutans that are most prominent in humans.

The histological effects of composite resin materials on the pulps of monkey teeth.

Pulpal response of three bis glycol methacrylate composite resins, Smile, Simulate and Experimental Composite no. 2 were tested on primary and permanent monkey teeth using zinc oxide eugenol (ZOE) and silicate as controls. All materials were placed in Class V cavity preparations in Rhesus monkey teeth and evaluated at 3 days and 5 and 8 weeks. The materials were randomly placed in anterior and posterior teeth utilizing 75 primary and 75 permanent teeth. Following perfusion the teeth were prepared by routine histological procedures. The 3 day response of the composite resins was moderate, characterized by disruption of the odontoblasts, vacuolization and mild inflammatory response underlying the cavity. At 5 weeks the formation of reparative dentin and a decrease in the inflammatory response was similar for all resins observed. At 8 weeks a slight increase in reparative dentin and continued decrease in inflammation was noted when compared to the 5 weeks responses. At all time intervals ZOE produced the least pulpal response while silicate produced the most severe response.

Histopathologic evaluation of the effects of four calcium hydroxide liners on monkey pulps.

Pulpal response of four calcium hydroxide liners, MPC 10, MPC 12, Dycal and Pulpdent were tested on primary and permanent teeth with zinc oxide and eugenol (ZOE) and silicate as controls. Responses of the pulps were evaluatedi in Rhesus monkeys, utilizing Class V cavity preparations at 3 days, 5 and 8 weeks. An equivalent number of anterior and posterior teeth were studied for all compounds. The Ca(OH)2 liners, zinc oxide and eugenol (ZOE) and silicate controls were placed in 80 primary and 80 permanent teeth. Following perfusions the teeth were prepared utilizing routine histological procedures. The 3 day response of the calcium hydroxides was moderate with some disruption in the odontoblasts, vacuolization and mild inflammation underlying the cavity except Pulpdent which was more severe. At 5 weeks a decrease in inflammatory response and the formation of reparative dentin was similar for all calcium hydroxides tested at this time period. At 8 weeks more reparative dentin was noted with slight to moderate pulpal responses. At all time periods ZOE produced the least pulpal response while silicate produced the most severe response at 5 and 8 weeks. This study reports the biological responses of four calcium hydroxide compounds used as cavity liners in non-exposures in a series of primary and permanent teeth of monkeys using ZOE and silicate as controls. Responses to the four Ca(OH)2 compounds were moderate for all the experimental compounds except Pulpdent which was more severe at the early time period tested. ZOE produced a milder and silicate a severe response at all periods. All of these compounds were placed by random selection in anterior and posterior teeth of both arches and five teeth were evaluated in both primary and permanent teeth at 3 days, 5 and 8 weeks.