Biomedical subjects

K H Kunzelmann

Publications and source records attributed to K H Kunzelmann.

40 records · Page 3Linked to original sources

PubMedDate not supplied

Physical properties and gap formation of light-cured composites with and without 'softstart-polymerization'.

OBJECTIVES: Recently it has been pointed out that light-initiated prepolymerization at low intensity followed by a post-light-cure at full intensity ('softstart-polymerization') may lead to light-cured composite fillings with improved marginal adaptation. The aim of this study was to examine the influence of this procedure with different initial cure conditions on physical material properties like flexural modulus, flexural strength and Vickers microhardness of different composites. Additionally, an in vitro study was carried out to investigate the influence of different initial cure conditions on the marginal quality of composite restorations in cases of Class V cavities with a cemento-enamel junction. METHODS: Physical properties of composite materials Tetric (Vivadent, Liechtenstein) and Charisma (Kulzer, Germany) were evaluated. Three hundred specimens were made for the flexural tests performed similar to EN 24049:1993. Microhardness was measured with a Vickers indenter. For the in vitro study of Class V composite fillings, cavities of 32 extracted teeth were filled with Tetric and analysed by quantitative marginal gap analysis and dye penetration test before and after thermocycling. RESULTS: The results indicate that initial cure with decreased light intensity followed by final cure with high light intensity has no influence on microhardness and increases flexural modulus and flexural strength. With the low-level initial cure/high-level final cure regime the marginal integrity was significantly better compared with the high light intensity curing system. CONCLUSION: Therefore, initial cure with low light intensity followed by final cure with high light intensity significantly improves the marginal integrity of light-cured composite fillings and also the material properties.

Chemical Phenomena↗

PubMedDate not supplied

Tooth-colored filling materials for the restoration of cervical lesions: a 24-month follow-up study.

The recently developed resin-modified glass ionomer cements and the polyacid-modified composites are promising alternatives to conventional materials for restoring cervical defects. This clinical study evaluated the clinical condition of cervical fillings 24 months following placement. The study subjects were 197 cervical restorations placed on incisors, canines and premolars in 37 patients for restoration of erosion/non-carious lesions (69 cases), primary carious lesions (57 cases) and the replacement of deficient restorations (71 cases). The teeth were randomly divided into four groups for restoration with either Tetric (composite, Group A: n = 36), Dyract (compomer, Group B: n = 79), Fuji II LC (resin-modified glass ionomer cement, Group C: n = 51) or Photac-Fil (resin-modified glass ionomer cement, Group D: n = 31). The evaluation was done single-blind at baseline, 8 and 24 months after the placement of the fillings, according to a modified USPHS rating scale. The assessment criteria were color stability, anatomical form, surface texture, marginal integrity, marginal discoloration and loss of filling. Statistical analysis was completed using Pearson chi-square and Fisher's exact test at a significance level of 5% (p < 0.05). After the 24-month period, the composite restorations showed superior results. The compomer fillings demonstrated conditions that were only slightly worse. A substantial number of the resin-modified glass-ionomer fillings were evaluated with bravo or even charlie scores in respect to at least one of the criteria assessed.

Adult↗

PubMedDate not supplied

Marginal quality of tooth-colored restorations in class II cavities after artificial aging.

This in vitro study compared the proximal marginal adaptation of direct composite restorations with composite and ceramic inlays inserted with different resin cements. Standardized MOD Class II inlay cavities with one proximal box extending below and the other above the CEJ were cut in 48 extracted human molars and randomly assigned to six groups (n=8). Incrementally layered direct composite restorations (P60), composite inlays (P60) and ceramic inlays (Empress; Cerec Vitablocs Mark II) were placed in the cavities. Three different resin cements (RelyX ARC; Variolink II high viscosity; Panavia 21) were used for luting the composite inlays. All ceramic inlays were cemented with RelyX ARC. After finishing and polishing, the teeth were stored for 24 hours in Ringer solution at 37 degrees C before they were subjected to thermal and mechanical loading (5/55 degrees C, 2000x; 50 N vertical load, 50000x). Margins were evaluated on epoxy replicas using a scanning electron microscope at X200 magnification. Statistical analysis was performed with non-parametric test methods (alpha=0.05). The adhesive interfaces to enamel exhibited high percentages of perfect margins for all groups (91.8% to 96%) and a maximum of 5.2% marginal gap formation. Dentin-limited cavity segments demonstrated more marginal openings and less perfect margins than enamel-bound areas; however, this was only statistically significant for direct composite restorations and composite inlays inserted with Variolink II and Panavia 21. RelyXARC showed a significantly better adaptation to P60 inlays compared with the leucite-reinforced Empress ceramic but not the Vitablocs Mark II ceramic.

Aluminum Silicates↗

PubMedDate not supplied

Experience with midazolam as sedative in the dental treatment of uncooperative children.

Shortage of capacity, and the limited range of therapies available for dental treatment of uncooperative children involve obvious problems which have given rise to new developments in treatment. Over the last two years, 83 children have been treated in 181 sessions after sedation with Midazolam. Rectal application is clearly superior to giving the drug orally. The results, and the good amnestic effect of Midazolam show that sedation employing this drug, while not a substitute for general anaesthesia in every case, does constitute an important alternative in the treatment of uncooperative children.

Administration, Oral↗