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Biomedical subjects

J W Curtis

Publications and source records attributed to J W Curtis.

30 records · Page 2Linked to original sources
PubMedDate not supplied

Retrofitting an esthetic post and core to salvage a six-unit fixed partial denture.

Teeth restored with post and core restorations present a clinical dilemma if they fracture. An individual with a maxillary anterior six-unit fixed partial denture had one of the canine abutment teeth fracture. The other abutment debonded and the post separated from the core. The fixed partial denture was salvaged by retrofitting a porcelain-fused-to-metal post and core restoration in the fractured abutment.

Cuspid↗
PubMedDate not supplied

Cariostatic and ultraconservative sealed restorations: nine-year results among children and adults.

The objective of this clinical study was to evaluate the long-term efficacy of placing sealed posterior composite restorations for arresting active caries. The tooth preparation for this bonded and sealed restoration was limited to placing a bevel in the enamel only, without the removal of the carious lesion. The radiographic and clinical performance of these ultraconservative sealed composite restorations placed over caries (CompS/C) was compared over a period of nine years with: 1) ultraconservative, localized sealed amalgam (AGS) restorations with no extension for prevention, and 2) traditional, unsealed amalgam restorations (AGU) with the usual extension for prevention outline form. Sealant retention with > 50 percent to 100 percent of the margins occurred in 64 percent of CompS/C and 82.5 percent of AGS restorations. After nine years the cumulative failure rates were 16 percent for CompS/C, 2.5 percent for AGS, and 17.1 percent for AGU restorations. Thus, the clinical performance of CompS/C restorations was slightly superior to that of the traditional AGU restorations. The AGS restorations were definitely superior to the traditional AGU restorations and to the CompS/C restorations in both children and adults alike. Complete sealant retention over CompS/C and AGS restorations was equivalent between children and adults (P = 0.14 and 0.74, respectively). A higher percentage of open margins in CompS/C restorations was seen, however, in children (17.4 percent) than adults (1.94 percent). This study has shown that Class I caries can be arrested by the CompS/C restoration.

Adolescent↗
PubMedDate not supplied

A predictive model for the polymerization of photo-activated resin composites.

This study investigated the relative significance of irradiation duration (20, 40, 60, or 80 seconds) and intensity; filler type (Silux Plus, a microfill or P-50, a hybrid); and shade (Universal or Gray) on the polymerization of resin composite within the depth of a simulated photopolymerized restoration. From the data, a mathematical model that predicts the extent of resin polymerization based upon the above stated variables was generated. The monomer conversion of specimens was determined by infrared spectroscopy. The results are of great clinical use and indicate that the most significant factor influencing resin composite polymerization is thickness of overlying resin composite. Both duration of exposure and light intensity demonstrate high and equal impact. Color and filler type have only minimal influence. The predictive model for resin composite polymerization provided a very good fit (r2 = .949).

Analysis of Variance↗
PubMedDate not supplied

Effect of light intensity and exposure duration on cure of resin composite.

Of the many factors under their control, clinicians can manipulate light-exposure duration but must deal with a set intensity of light emitted from the dental curing unit. This research investigates the interdependence of exposure duration and source intensity on resin cure at various depths within a simulated light-cured resin composite restoration. This wafers of composite were obtained from a simulated cylindrical restoration such that the wafer could be removed from the top or from a distance of 1, 2, and 3 mm beneath the surface. The composites used in this study were a microfill and hybrid of Universal and Gray shades. All the data concerning filler type and shade were pooled so that generalized statements could be made regarding curing of light-activated composite in general. Specimens were cured using various source intensities and for different durations at each level within the cured cylinder. The cure of the specimens resulting from the different treatments was determined using infrared spectroscopy. The results indicate a dramatic effect of depth on the cure of composite. At depths greater than 2 mm, poor cure results, and polymerization is very susceptible to changes in light intensity and exposure duration. From these results, routine exposure times of 60 seconds are recommended using light-source intensities of at least 400 mW/cm2 as measured with a commercial dental light intensity meter. Incremental layer thickness should not exceed 2 mm, with 1 mm being ideal. Sources with intensity values less than 233 mW/cm2 should not be used because of their poor cure characteristics.

Absorption↗
PubMedDate not supplied

Implant placement and restoration following bone marrow transplantation for chronic leukemia: a case report.

Bone marrow transplantation is used with increasing frequency to treat various hematologic diseases, particularly the leukemias. A case involving dental implant therapy in a woman who had undergone successful allogeneic bone marrow transplantation for treatment of chronic myelogenous leukemia is presented to illustrate specific considerations in treatment planning, surgical management, and overall prosthetic rehabilitation. Five mandibular endosseous implants were placed in November 1991 and subsequently restored with a fixed detachable prosthesis. The patient experienced no complications related to the implants or prosthesis during the 3 years after restoration.

Adult↗