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Biomedical subjects

D R Haselton

Publications and source records attributed to D R Haselton.

5 recordsLinked to original sources
PubMed2001

Shear bond strengths of 2 intraoral porcelain repair systems to porcelain or metal substrates.

STATEMENT OF PROBLEM: When clinical fractures of the ceramic veneer on ceramometal can be repaired, the need for remake can be eliminated or postponed. A number of ceramic repair materials are available; bond strength data would be useful for predicting the success of a given repair system. PURPOSE: This in vitro study evaluated shear bond strengths of 2 porcelain repair systems intended for intraoral bonding of resin to porcelain and metal. MATERIAL AND METHODS: Sixty cylindrical specimens were fabricated with feldspathic porcelain and/or a high noble alloy: 20 porcelain (P), 20 porcelain and metal (PM), and 20 metal (M). Specimens were divided into subgroups of 10, and resin composite cylinders were bonded with 1 of 2 systems: CoJet-System (CJ) or Ceramic Repair (CR). Bonded specimens were stored in 37 degrees C distilled water for 24 hours before being thermocycled at 5 degrees C to 55 degrees C for 300 cycles with a 30-second dwell time. The specimens then were stored for an additional 8 days before being subjected to shear force in a universal testing machine at a crosshead speed of 5 mm/min. Stress at failure was calculated in MPa, and mode of failure was recorded. Analysis of variance (ANOVA) was applied to the data. Comparisons between substrates were made with the Duncan multiple range test (P <.05), and differences between the 2 repair systems within like substrate groups were examined with the Student t test. RESULTS: Bonding groups exhibited the following values in megapascals: PM-CR = 19.3 +/- 4.1; PM-CJ = 25.0 +/- 3.1; M-CR = 14.3 +/- 4.9; M-CJ = 23.0 +/- 2.3; P-CR = 18.3 +/- 4.2; P-CJ = 22.4 +/- 5.6. The ANOVA results showed significant differences between the CJ and CR groups. The Student t test revealed that the mean data for the CJ groups were significantly higher than for the CR groups (P <.05). The Duncan multiple range test demonstrated significant differences between the PM and M groups (P <.05) for the CR system only. CONCLUSION: Under the conditions of this study, CJ achieved significantly higher bond strengths to PM and M substrates. Significant differences in strength were found between PM and M, but only within the CR system.

Acid Etching, Dental↗
PubMed2000

Clinical assessment of high-strength all-ceramic crowns.

STATEMENT OF PROBLEM: All-ceramic crowns are being used extensively. Little data are available on their clinical performance. PURPOSE: This study evaluated the clinical performance of In-Ceram (Vita Zahnfabrik) crowns. MATERIAL AND METHODS: Forty-one patients (16 men, 25 women; mean age 47.3 years, range 18 to 77 years) were examined with a total of 80 In-Ceram all-ceramic crowns fabricated at the University of Iowa College of Dentistry from 1994 to 1997. The percentage distribution for crowns included: 67% anterior single crowns, 26% posterior single crowns, 6% anterior implant crowns, and 1% posterior implant crowns. This study documented the integrity of the junction between crown and tooth, color match to adjacent teeth, secondary dental caries, wear of crown and opposing dentition, and visible cracks in the crown. Alpha, Bravo, and Charlie ratings were assigned with a modified USPHS criteria. The patients were also surveyed with respect to oral hygiene and satisfaction of treatment. Estimations of 4-year success rates and corresponding confidence intervals were calculated by fitting a constant hazard function model with the SAS procedure GENMOD. RESULTS: Marginal integrity for 88% of artificial crowns was rated Alpha or Bravo. Shade match for 99% was Bravo or better. Only 1% of the crowns were carious, and 1 crown exhibited occlusal wear. One premolar crown had a small fracture of veneering porcelain. One molar crown was remade after core fracture. All patients (100%) expressed satisfaction with their crowns. The estimated 4-year success rates (Alpha or Bravo), with 95% confidence intervals in parentheses were calculated as: 83.5% (65.7%-94.6%) for marginal integrity, 95.8% (82.9%-99.8%) for shade match, and 95.5% (81.6%-99.7%) for secondary caries, 100% (88%-100%) for wear, and 100% (88%-100%) for cracks.

Adolescent↗
PubMed2000

A comparison of the effects of two burs on endodontic access in all-ceramic high lucite crowns.

OBJECTIVE: The purpose of this study was to examine and compare the effects of diamond and tungsten carbide burs with respect to the preparation of access through all-ceramic crowns. STUDY DESIGN: Thirty extracted maxillary premolars were restored with all-ceramic crowns. Each specimen was assigned to one of two groups: (1) access opening prepared with a round diamond bur; (2) access opening prepared with a carbide fissure bur. Access preparations were scanned by means of scanning electron microscopy; observed were defects categorized as edge chipping, microcracks, and fractures. RESULTS: Edge chipping around the access was universal. Significant chipping (x > or = 0.1 m) was seen in 43% of access peripheries. Eleven percent of the crowns fractured. chi(2) analysis (P <.05) demonstrated no statistical difference between the bur groups. Results of a t test revealed no statistical difference in edge chipping between the two bur types. CONCLUSIONS: All-ceramic crowns bonded to extracted maxillary premolars may experience edge chipping, microcracks, and fractures at equal rates whether access is prepared with a round medium coarse diamond bur or a tungsten carbide fissure bur.

Bicuspid↗
PubMed1999

Current status of luting agents for fixed prosthodontics.

STATEMENT OF THE PROBLEM: The long-term clinical outcome of fixed prosthodontic treatment depends, in part, on the use of adhesives that can provide an impervious seal between the restoration and the tooth. There are several types of available luting agents, each possessing unique properties and handling characteristics. No one product is ideal for every type of restoration. PURPOSE: The purpose of this article is to review available dental luting agents, discuss improvements and drawbacks in newly formulated adhesives, and present the indications for their use. RESULTS: Each cement type is physically and chemically unique. A single adhesive will not suffice in modern day clinical practice.

Adhesives↗