ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00418.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

PurposeThe in vivo wear resistance of 12 composite resins were compared with an amalgam control using the Latin Square experimental design. Sixteen edentulous patients wearing specially designed complete dentures formed the experimental population.Materials and MethodsThe Michigan Computer Graphics Measurement System was used to digitize the surface of the control and composite resin samples before and after 3‐month test periods to obtain wear data. The 12 composite resins selected for this investigation based on their published composite classification types were seven fine particle composites, three blends, and two microfilled composite resins. The Latin Square experimental design was found to be valid with the factor of material being statistically different at the 5% level of significance. Wear was computed as volume loss (mm3/mm2), and all of the composites studied had more wear than the amalgam control (P= .001).ResultsAfter 3 months, the mean (error) of wear of the amalgam was 0.028 (0.006). Means (error) of wear for the 12 composites were ranked from most to least wear by mean wear volume loss.ConclusionsThe absence of any relationship between mean wear volume loss and the volume percentage filler was confirmed by the correlation coefficientr= ‐0.

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00419.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

This article addresses the complex nature of retention in a removable partial denture. Retentive features range from magnets and springs to clips, clasps, and interfacial surface tension. The retentive quality of an extracoronal clasp varies with the alloy, physical form, location on the abutment, and positional relationship to other elements. Surveying to identify both occlusogingival and mesiodistal undercuts when the path of random dislodging forces are not definitely controlled is needed for effective retention. Augmentation of ineffective retention in existing clasps should concentrate on methods of deepening the undercut or increasing the suprabulge. Tightening of clasps already in contact with a tooth frequently produces adverse changes.

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00420.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

PurposeThis study compared the stress distribution of three porcelain‐fused‐to‐metal labial margins on a central incisor under simulated occlusal force.Materials and MethodsThe margin designs were rounded‐shoulder, rounded‐shoulder with a bevel, and a chamfer.ResultsEvaluation of mean equivalent Mises tensile stress did not show any difference at the cement‐dentin and metal‐cement interfaces of the three margins. The mean equivalent Mises tensile stress at the porcelain‐metal interface was found to be significantly higher for rounded‐shoulder when compared with the chamfer. There was no significant difference in the axial stresses along the three interfaces among the three margin designs. Statistically significant differences in radial stresses at some interfaces of the three margin designs were found.ConclusionsThe change of cement thickness of the chamfer margin is significantly greater than that of either the rounded‐shoulder or the bevel

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00421.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

PurposeThis investigation compared the stress production characteristics of five abutment angulations for a specific implant system.Materials and MethodsPhotoelastic resin was cast directly to a 3.75 × 10‐mm Branemark fixture (Nobelpharma USA, Inc, Chicago, IL) in a 50 × 70 × 13‐mm mold. A strain gauge rosette was also incorporated in the resin to allow precise determination of normal stresses at a specific point. Each 4‐mm abutment (15°, 25°, and 35° from Implant Innovations (West Palm Beach, FL) and 0° and 30° from Nobelpharma) was assembled on the fixture, subjected to 178N load, and viewed with a circular polariscope. Observed fringes were photographed and strain indicator readings were recorded.ResultsMean observed fringe order and mean principal stress and strain at the location of the rosette were determined.ConclusionsAt the location of the rosette, all five of the abutments produced principal strains (compressive and tensile) within the physiological zone for bone. The rosette was located approximately 4 mm away from the fixture. Higher stresses and strains can be expected in regions closer t

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00422.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

PurposeImplantation of commercially pure titanium dental implants can be obtained predictably and consistently. The initial research focused on the edentulous population, with most of the fixtures being placed into the anterior mandibular area. There has been increased use of dental implants for partially edentulous patients.Materials and MethodsThis study reports the results of 169 consecutively treated patients with 673 fixtures. Patients were observed for 7 months to 8 years following occlusal loading.ResultsImplant osseointegration was 89.1% in the anterior maxillae; 71.4% in the posterior maxillae; 96.7% in the anterior mandible; and 98.7% in the posterior mandible.ConclusionsOsseointegration may be most dependent on anatomical location in the jaws.

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00423.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

PurposeIn the American National Standards Institute/American Dental Association specification no. 19, compatibility of impression materials with dental stones is assessed by the presence of a 20μm‐wide line reproduced on an unmodified calcium sulfate dihydrate cast. In actual dental practice, modified type IV dental stones are used, although little is known of their compatibility with polysulfide impression materials. This study evaluated the compatibility of 6 polysulfide impression materials and 11 modified type IV dental stones.Materials and MethodsA line 20 μm wide was etched on four glass dies. Four samples of each combination of impression material and dental stone were prepared according to the manufacturer's directions with an additional 3 minutes for the final setting time. Compatibility was determined by the presence of the reproduced line on the dental stones, as observed under low angle 10 × magnification by four rater groups.ResultsThe line was reproduced on all of the impression specimens, and the examiners recorded 66 positive identifications of the line on the stone casts out of a possible 1,056 ratings for a total of 6.25% of the specimens. Out of a possible 66 impression‐stone combinations, only 18 reproduced the 20‐μm line. The combinations reproducing the lines most frequently (75%) were Neoplex with Blue Die Stone (Columbus Dental, St Louis, MO) and Coeflex with Indic Die Stone (Coe Lab Inc, Chicago, IL).ConclusionsThe study showed that many combinations of polysulfide impression materials and modified type IV dental stones did not reproduce the 20‐μm line; therefore, not every polysulfide is compatible with every type IV

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00424.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

An increasing number of head and neck cancer patients are undergoing radiotherapy along or in conjunction with other treatment modalities. Radiotherapy extending over a period of weeks produces a variety of clinical manifestations. This article discusses the physiological changes that occur due to radiotherapy to elucidate the changes seen clinically.

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00425.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

A temporomandibular disorder (TMD) conference was convened in 1982 by the president of the American Dental Association. One of the objectives was to develop guidelines for a brief screening history and examination relative to TMD in order to determine whether there is a need for a more comprehensive evaluation, Based on these guidelines and under the auspices of the American College of Prosthodontists, this article discusses a simplified TMD screening and examination form that requires minimum time for both the patient (history) and health care provider (examination) to complete. Succinct recommendations are also presented to enable the health care provider to quickly determine if a more detailed TMD history and examination are warranted.

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00426.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Does the undergraduate dental curriculum devote the appropriate amount of time to those areas of dentistry that are relevant to today's general dental practice? In a survey of dentists who graduated between 1980 and 1985, it was determined that they felt curriculum offerings in orthodontics, research, endodontics, periodontics, oral surgery, fixed prosthodontics, and occlusion had not been extensive enough. However, graduates also reported that their educational experiences in biochemistry, dental laboratory procedures, gross anatomy, microbiology, and occlusion were too extensive.

ISSN:1059-941X    

DOI:10.1111/j.1532-849X.1992.tb00427.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY