General Dentistry/ Matrix Systems Chapters 48 & 49

Restorative Dentistry Indicated when teeth must be restored to their original structure by the use of direct or indirect restorative materials. Conditions that determine the need for restorative dentistry: Initial or recurring decay Replacement of failed restorations Abrasion or wearing away of tooth structures Erosion of tooth structure

Esthetic Dentistry Primarily devoted to improving the appearance of teeth by either restoring imperfections with direct or indirect restorative materials Specific conditions that initiate a need for esthetic treatment include the following Discoloration due to extrinsic or intrinsic staining Anomalies caused by developmental distrubances Abnormal spacing between teeth trauma

Cavity Preparation Process of removing unhealthy tooth structure while leaving a limited amount of healthy tooth structure for the tooth to maintain a restoration Two stages: Initial preparation Access to decay Outline form Primary resistance form

Final preparation Remove any remaining enamel in the prep Additional resistance and retention Place protective materials

Terminology Cavity Wall: Internal wall: External wall: Internal surface of tooth prepared for the restoration Internal wall: Cavity wall/surface that does not extend to the external tooth surface External wall: Surface of the tooth preparation that extends to the external tooth surface, named according to the tooth surface involved; distal, mesial, facial, lingual, gingival

Axial wall: Pulpal wall: Internal wall/surface of the prepared tooth that runs parallel to the long axis of the tooth Pulpal wall: Internal wall/surface of a prepared tooth that is perpendicular to the long axis of the tooth; also known as the pulpal floor

Line angle: Angle formed by the junction of two walls/surface in a cavity preparation (such as a corner) The names of the two walls are combined and form a new angle. Such as mesial and lingual, and becomes mesiolingual angle.

Classifications Class I Class II Class III Small and involves the pits and fissures of teeth Class II Extension of Class I, into the proximal surface(s) of premolars and molars Class III Affects the interproximal surface (mesial or distal) of incisors and canines

Class IV Involves larger surface area, that includes the incisal edge and the interproximal surface of incisors and canines Class V Smooth surface restorations Gingival third of the facial or lingual surfaces of any tooth

Complex Restorations When the loss of the tooth structure becomes greater than the remaining natural tooth that is left. Decision has to be made whether to restore with a crown or direct restoration (such as amalgam or composite) If a direct restoration is decided upon, Retention Pins may be needed. Pins provide stronger system for retaining and supporting the restoration other than retentive grooves or bonding materials

Retention Pins May be required when tooth decay has extended into the distolingual cusp, undermining the enamel and dentin. One pin would be placed for each missing cusp

Veneers A thin layer of tooth colored material that is applied to the facial surface of a prepared tooth. Can be used for more than one tooth Improves appearance, (such as) Slightly abraded Eroded Dicolored (intrinsic stains or after endo treatment) Alignment (diastema)

Tooth Whitening Also known as Vital bleaching Noninvasive method of lightening of teeth In office and at-home methods Three primary indications for use Extrinsic stains from foods, smoking, coffee or tea Aged teeth Intrinsic stains (tetracycline stains and mild fluorosis

Typical Amalgam Tray Set-up Basic set-up Hand cutting instruments Condenser Ball burnisher Carvers Amalgam carrier Articulating paper/holder

Set-Up Cont. HVE/saliva ejector Handpieces Burs Dental floss Cotton rolls/holder Misc. Matrix band/retainer Guaze squares Anesthetic set-up Dental dam set-up

Matrix Systems Creates a temporary wall for amalgam, composite resin or IRM material Posterior Matrix systems Tofflemire retainer Know the parts of the retainer and their function Band Made of thin flexible stainless steel Center of the band must be contoured(shaped) in the proximal surfaces for contact

Matrix Cont. Wedges Class II restoration require wedges Placed on lingual embrasure Various sizes and forms, wood or plastic

Anterior Matrix Clear plastic Used with composite resin or glass ionomer Stainless steel matrix can scratch or mark the composite resin material Also referred to as celluloid strip or Mylar strip.

Automatrix System Alternative to the use of Tofflemire system Does not use retainer to hold in place Bands are already formed

Matrix Systems for Primary Teeth T-bands Copper band in shape of a T When formed the top of the band allows the straight portion to adjust and fit the circumference of the primary molar.