The effect of mechanical loading on the cusp defection of premolars restored with direct and indirect techniques.

Abstract

AIM:

This study assessed the effect of fatigue load cycling on human premolars restored with MOD restorations (direct and indirect approaches) on cuspal defection, compared to intact teeth (unprepared) and unrestored teeth with an inlay preparation.

MATERIALS AND METHODS:

MOD inlay preparations were performed on sixty premolars with their roots embedded in acrylic resin. These teeth were divided into six groups (n = 10): (1) intact teeth; (2) unrestored and prepared teeth; (3) teeth restored with direct composite resin; (4) teeth restored with an indirect composite resin; (5) teeth restored with injected ceramic inlays (IPS Empress 2 (Ivoclar); (6) teeth restored with CAD/CAM inlays made of feldspathic ceramic (Vita Mark II). All of the indirect restorations were adhesively cemented. Strain-gauges were bonded to the buccal and lingual surfaces of the specimens. Compressive axial loading of 100N was applied on the occlusal face of the specimens to measure the cuspal deflection (microstrain) under compressive loading. These measurements were obtained before and after mechanical cycling (1 Hz, 37°C, 100,000x).

RESULTS:

Comparing the results obtained before and after fatiguing, the cuspal defection increased only in the CAD/CAM approach. The prepared tooth group had the highest cuspal defection, before and after mechanical cycling.

CONCLUSION:

The evaluated restoring approaches decrease the cuspal defection, consequently appear to improve the cuspal reinforcement.

• Authors: Sandra Costa Zamboni, Lafayette Nogueira, Marco Antonio Bottino, Lourenço Correr Sobrinho, Luiz Felipe Valandro
• Journal: The journal of contemporary dental practice (J Contemp Dent Pract) Vol. 15 Issue 1 Pg. 75-81 (Jan 01 2014) ISSN: 1526-3711 [Electronic] India
• PMID: 24939269 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Aluminum Silicates
• Composite Resins
• Dental Materials
• Empress 2
• Lithium Compounds
• Polymethacrylic Acids
• Potassium Compounds
• RelyX ARC
• Resin Cements
• Scotchbond Multi-Purpose
• Sinfony composite resin
• filtek Z350
• Dental Porcelain
• feldspar
• Polyethylene Glycols
• Bisphenol A-Glycidyl Methacrylate
• Glass ceramics

Topics

• Acid Etching, Dental (methods)
• Aluminum Silicates (chemistry)
• Bicuspid (pathology)
• Bisphenol A-Glycidyl Methacrylate (chemistry)
• Ceramics (chemistry)
• Composite Resins (chemistry)
• Computer-Aided Design
• Dental Cavity Preparation (classification)
• Dental Materials (chemistry)
• Dental Porcelain (chemistry)
• Dental Restoration, Permanent (classification)
• Dental Stress Analysis (instrumentation)
• Humans
• Inlays
• Light-Curing of Dental Adhesives (instrumentation)
• Lithium Compounds (chemistry)
• Polyethylene Glycols (chemistry)
• Polymethacrylic Acids (chemistry)
• Potassium Compounds (chemistry)
• Resin Cements (chemistry)
• Stress, Mechanical
• Temperature
• Tooth Crown (pathology)