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.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66895/2/10.1177_00220345910700010901.pd

Clinical evaluation of chairside Computer Assisted Design/Computer Assisted Machining nano‐ceramic restorations: Five‐year status

ObjectivesThis investigation was a longitudinal, randomized clinical trial to measure the clinical performance of a nano‐ceramic material (Lava Ultimate/3M) for chairside Computer Assisted Design/Computer Assisted Machining (CAD/CAM) fabricated restorations.Materials and MethodsOne hundred and twenty chairside CAD/CAM onlays were restored with a CEREC system randomly assigned to 60 leucite‐reinforced ceramic (IPS EmpressCAD/Ivoclar Vivadent AGBendererstrasse 2FL‐9494 SchaanLiechtenstein) onlays and 60 nano‐ceramic (Lava Ultimate/3M) onlays. Equal groups of onlays were cemented using a self‐etch and a total etch adhesive resin cement. The onlays were recalled for a period of 5 years.ResultsAt 1 week postoperatively, 10% of the onlays cemented with both the self‐etch and total etch adhesive resin cements were reported as slightly sensitive. However, all patients were asymptomatic by the 4th week without treatment. Four leucite‐reinforced onlays and one nano‐ceramic onlay fractured and required replacement.ConclusionsAdhesive retention with a self‐etch or total etch cementation technique resulted in a similar clinical outcome with no reported debonds. The nano‐ceramic onlays had a lower incidence of fracture compared to the leucite‐reinforced ceramic onlays with both having a very low risk of fracture. Nano‐ceramic onlays performed equally as well as glass ceramic onlays over 5 years of clinical service.Clinical SignificanceCeramic materials have been a mainstay for chairside CAD/CAM restorations for the past 30 years and a new category of resilient ceramics with a resin matrix has been introduced reported to offer ceramic‐like durability and esthetics with resin‐like efficiency in handling. There are no long‐term clinical studies on the performance of these materials. This is a 5‐year randomized clinical trial on the performance of nano‐ceramic onlays.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154462/1/jerd12516.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154462/2/jerd12516_am.pd

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 evaluated 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.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74743/1/j.1600-0714.1976.tb01759.x.pd

Histopathologic Evaluation of three Ultraviolet-Activated Composite Resins on Monkey pulps

The pulpal responses of three ultraviolet-activated composite resins, Nuva-Fil®, Experimental UV #1® and Experimental UV #2®, were tested on adult monkey teeth using silicate and zinc oxide eugenol (ZOE) as positive and negative controls. All materials were placed in Class V cavity preparations in Rhesus monkey teeth using approximately 48 anterior and 63 posterior teeth of both the maxillary and mandibular arches. A total of 111 teeth were utilized and all materials were evaluated at 3 days, 5 and 8 weeks. Following left ventricular perfusion, the teeth were prepared for microscopic evaluation using routine histological procedures. The 3-day pulpal response of all the ultraviolet-activated composites was slight with some disruption and vacuolization in the odontoblastic layer and a slight inflammatory response. At 5 weeks there was a reduction of the inflammatory response and the formation of reparative dentin was noted for all ultraviolet composites. The 8-week pulp response was slight, characterized by a minimal inflammatory response adjacent to the zone of reparative dentin. Generally, ZOE produced the mildest response while silicate produced the most severe response at the three time intervals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74732/1/j.1600-0714.1977.tb01797.x.pd

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.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66484/2/10.1177_00220345800590020101.pd