Lecture Five: Failure of Composite Restoration PDF

Lecture Five Failure of composite restoration Dr kale masoud causes and potential solutions  The following list indicates the cause-s of common problems associated with some composite restorations, as well as potential solutions to those problems. 1-Poor isolation o...

Lecture Five Failure of composite restoration Dr kale masoud causes and potential solutions  The following list indicates the cause-s of common problems associated with some composite restorations, as well as potential solutions to those problems. 1-Poor isolation of the operating area: Causes:  No rubber dam or leaking rubber dam  Inadequate cotton roll isolation  Carless technique  Preparation so deep gingivally that cannot be isolated Potential solutions:  Better technique.  Use of matrix to help isolation.  Use of a non-bonded restorative material.  Repeat bonding procedures (if the area is contaminated). 2-White line or halo around the enamel margin: The following factors cause microfructure of marginal enamel:  Traumatic contouring or finishing techniques.  Inadequate etching and bonding of that area.  High-intensity light-curing resulting in excessive polymerization stress. Potential solutions:  Re-etch, prime, and bond the area.  Conservatively remove the fault and re-restore.  Use atraumatic finishing techniques (e.g. light intermittent pressure) Use low-start polymerization technique 3-Voids:  Causes:  Mixing of self-cured composite.  Spaces left between increments during insertion.  Tacky composite pulling away from the preparation during insertion.  Potential solutions:  More careful technique Repair of marginal voids be preparing the area and re-restoration 1 4-Weak or missing proximal contacts (classes II, III, and IV): Causes:  Inadequately contoured matrix band.  Inadequate wedging both preoperatively and during the composite insertion.  Matrix band movement during composite insertion, or matrix band not in direct contact with the adjacent proximal surface.  A circumferential matrix being when used when restoring only one contact.  Tacky composite pulling away from matrix contact area during insertion.  Matrix band too thick. Potential solutions:  Properly contour the matrix band.  Have matrix in contact with adjacent tooth.  Use firm preoperative and insertion wedging technique.  Use a matrix system that places matrix only around the proximal surface to be restored.  Use a hand instrument to hold the matrix against the adjacent tooth while curing the incremental placements of composite. Be very careful with insertion technique 5-Incorrect shade: Causes:  Inappropriate operator lighting while selecting the shade.  Selecting the shade after the tooth is dried.  Shade tab not matching the actual composite shade.  Wrong shade selection. Potential solutions:  Use natural light if possible.  Select the shade before isolating the tooth.  Preoperatively place some of the selected shade on the tooth and cure (then remove).  Do not shine operating light directly in the area during shade selection.  Understand the typical zones of different shades of natural teeth. 2 6-Poor retention: Causes:  Inadequate preparation form.  Contamination of operating area.  Poor bonding technique.  Intermingling of bonding materials from different systems. Potential solutions:  Prepare the tooth with appropriate bevels or flares and secondary retention feature, when necessary.  Keep the area isolated while bonding.  Follow the manufacturer's directions.  Do not inter mingle bonding materials from different system 7-Contouring and finishing problems:  Causes:  Injuring adjacent unprepared tooth structure.  Over-contouring the restoration.  Under-contouring the restoration.  Ditching cementum.  Creating inadequate anatomic tooth form. Potential solutions:  Be careful with use of rotary instruments to not adversely affect adjacent tooth structure or teeth.  Have a proper matrix with appropriate axial and line angle contours.  Create embrasures to match the adjacent tooth embrasure form.  Do not use rotary instruments that leave roughened surfaces.  Use a properly shaped contouring instrument for the area being contoured.  Remember the outline form of the preparation. View the restoration from all angles as it is contoured 3